umu.sePublikasjoner
Endre søk
Begrens søket
12 1 - 50 of 54
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Alfredson, Håkan
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin.
    Lorentzon, Mattias
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin.
    Bäckman, Stina
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Bäckman, Assar
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Lerner, Ulf H
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    cDNA-arrays and real-time quantitative PCR techniques in the investigation of chronic Achilles tendinosis.2003Inngår i: Journal of Orthopaedic Research, ISSN 0736-0266, E-ISSN 1554-527X, Vol. 21, nr 6, 970-975 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aetiology and pathogenesis of chronic painful Achilles tendinosis are unknown. This investigation aimed to use cDNA arrays and real-time quantitative polymerase chain reaction (real-time PCR) technique to study tendinosis and control tissue samples. Five patients (females mean age 57.1+/-4.3 (years+/-SD)) with chronic painful Achilles tendinosis were included. From all patients, one biopsy was taken from the area with tendinosis and one from a clinically normal area (control) of the tendon. The tissue samples were immediately immersed in RNAlater and frozen at -80 degrees C until RNA extraction. Portions of pooled RNA from control and tendinosis sites, respectively, were transcribed to cDNA, radioactively labelled (32P), hybridized to cDNA expression arrays, and exposed to phosphoimager screens over night. Expressions of specific genes, shown to be regulated in the cDNA array analysis, were analyzed in the individual samples using real-time PCR. cDNA arrays showed that gene expressions for matrix-metalloproteinase-2 (MMP-2), fibronectin subunit B (FNRB), vascular endothelial growth factor (VEGF), and mitogen-activated protein kinase p38 (MAPKp38) were up-regulated, while matrix-metalloproteinase-3 (MMP-3) and decorin were down-regulated, in tendinosis tissue compared with control tissue. Using real-time PCR, 4/5 and 3/5 patients showed up-regulation of MMP-2 and FNRB mRNA, respectively. For decorin, VEGF, and MAPKp38, real-time PCR revealed a great variability among patients. Interestingly, the mRNAs for several cytokines and cytokine receptors were not regulated, indicating the absence of an inflammatory process in chronic painful Achilles tendinosis. In conclusion, cDNA-arrays and real-time PCR can be used to study differences in gene expression levels between tendinosis and control tendon tissue.

  • 2. Andersson, MK
    et al.
    Lundberg, Pernilla
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Ohlin, A
    Perry, MJ
    Lie, Anita
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Stark, A
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Effects on osteoclast and osteoblast activities in cultured mouse calvarial bones by synovial fluids from patients with a loose joint prosthesis and from osteoarthritis patients.2007Inngår i: Arthritis Research & Therapy, ISSN 1478-6362, Vol. 9, nr 1, R18- s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aseptic loosening of a joint prosthesis is associated with remodelling of bone tissue in the vicinity of the prosthesis. In the present study, we investigated the effects of synovial fluid (SF) from patients with a loose prosthetic component and periprosthetic osteolysis on osteoclast and osteoblast activities in vitro and made comparisons with the effects of SF from patients with osteoarthritis (OA). Bone resorption was assessed by the release of calcium 45 (45Ca) from cultured calvariae. The mRNA expression in calvarial bones of molecules known to be involved in osteoclast and osteoblast differentiation was assessed using semi-quantitative reverse transcription-polymerase chain reaction (PCR) and real-time PCR. SFs from patients with a loose joint prosthesis and patients with OA, but not SFs from healthy subjects, significantly enhanced 45Ca release, effects associated with increased mRNA expression of calcitonin receptor and tartrate-resistant acid phosphatase. The mRNA expression of receptor activator of nuclear factor-kappa-B ligand (rankl) and osteoprotegerin (opg) was enhanced by SFs from both patient categories. The mRNA expressions of nfat2 (nuclear factor of activated T cells 2) and oscar (osteoclast-associated receptor) were enhanced only by SFs from patients with OA, whereas the mRNA expressions of dap12 (DNAX-activating protein 12) and fcrgamma (Fc receptor common gamma subunit) were not affected by either of the two SF types. Bone resorption induced by SFs was inhibited by addition of OPG. Antibodies neutralising interleukin (IL)-1alpha, IL-1beta, soluble IL-6 receptor, IL-17, or tumour necrosis factor-alpha, when added to individual SFs, only occasionally decreased the bone-resorbing activity. The mRNA expression of alkaline phosphatase and osteocalcin was increased by SFs from patients with OA, whereas only osteocalcin mRNA was increased by SFs from patients with a loose prosthesis. Our findings demonstrate the presence of a factor (or factors) stimulating both osteoclast and osteoblast activities in SFs from patients with a loose joint prosthesis and periprosthetic osteolysis as well as in SFs from patients with OA. SF-induced bone resorption was dependent on activation of the RANKL/RANK/OPG pathway. The bone-resorbing activity could not be attributed solely to any of the known pro-inflammatory cytokines, well known to stimulate bone resorption, or to RANKL or prostaglandin E2 in SFs. The data indicate that SFs from patients with a loose prosthesis or with OA stimulate bone resorption and that SFs from patients with OA are more prone to enhance bone formation.

  • 3. Baldock, PA
    et al.
    Allison, SJ
    Lundberg, Pernilla
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Lee, NJ
    Slack, K
    Lin, EJ
    Enriquez, RF
    McDonald, MM
    Zhang, L
    During, MJ
    Little, DG
    Eisman, JA
    Gardiner, EM
    Yulyaningsih, E
    Lin, S
    Sainsbury, A
    Herzog, H
    Novel role of Y1 receptors in the coordinated regulation of bone and energy homeostasis.2007Inngår i: Journal of Biological Chemistry, ISSN 0021-9258, Vol. 282, nr 26, 19092-19102 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The importance of neuropeptide Y (NPY) and Y2 receptors in the regulation of bone and energy homeostasis has recently been demonstrated. However, the contributions of the other Y receptors are less clear. Here we show that Y1 receptors are expressed on osteoblastic cells. Moreover, bone and adipose tissue mass are elevated in Y1(-/-) mice with a generalized increase in bone formation on cortical and cancellous surfaces. Importantly, the inhibitory effects of NPY on bone marrow stromal cells in vitro are absent in cells derived from Y1(-/-) mice, indicating a direct action of NPY on bone cells via this Y receptor. Interestingly, in contrast to Y2 receptor or germ line Y1 receptor deletion, conditional deletion of hypothalamic Y1 receptors in adult mice did not alter bone homeostasis, food intake, or adiposity. Furthermore, deletion of both Y1 and Y2 receptors did not produce additive effects in bone or adiposity. Thus Y1 receptor pathways act powerfully to inhibit bone production and adiposity by nonhypothalamic pathways, with potentially direct effects on bone tissue through a single pathway with Y2 receptors.

  • 4.
    Belibasakis, Georgios N.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Cellular and molecular responses of periodontal connective tissue cells to Actinobacillus actinomycetemcomitans cytolethal distending toxin2004Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Actinobacillus actinomycetemcomitans is present in elevated proportions and numbers in dental bacterial biofilms of patients with localized aggressive periodontitis. This variant of periodontal disease, occurring in adolescents and young adults, is characterized by rapid and severe destruction of the connective tissues and bone supporting the teeth, eventually culminating in tooth loss. The cytolethal distending toxin (Cdt) is a newly discovered bacterial protein toxin, uniquely present in A. actinomycetemcomitans among all known to-date oral bacterial species. The Cdt has the capacity to inhibit mammalian cell growth, but its putative role in the pathogenesis of the disease is unclear. The aim of this in vitro work has been to study the effects of A. actinomycetemcomitans on periodontal connective tissue cell cultures, and to evaluate the possible involvement of its Cdt.

    A. actinomycetemcomitans inhibited the proliferation of gingival and periodontal ligament fibroblasts, as a result of a combined arrest at the G1 and G2/M phases of the cell cycle. This growth inhibition was non-lethal and the cells remained metabolically active, although their DNA synthesis was reduced. The intoxicated cells exhibited increased size and irregular structure, characterized by distension and elongation. This cellular enlargement occurred in both G1 and G2/M phase arrested cells. The Cdt of A. actinomycetemcomitans was responsible for the observed growth inhibition, as well as the concomitant morphological alterations.

    The possible induction of inflammatory cytokines related to bone resorption was investigated in response to A. actinomycetemcomitans, and the involvement of Cdt was evaluated. Extensive focus was given to the study of receptor activator of NF-κB ligand (RANKL) expression, a membrane-bound ligand that signals osteoclast progenitors to differentiate and fuse into mature osteoclasts, activating bone resorption. It was demonstrated that A. actinomycetemcomitans induced RANKL mRNA and protein expression in the cells studied, but did not affect the expression of its decoy receptor, osteoprotegerin. This induction was solely attributed to its Cdt, as demonstrated by the use of a cdt-knockout A. actinomycetemcomitans strain, purified recombinant Cdt, and antibodies blocking the Cdt. In addition, this event was not mediated by pro-inflammatory cytokines known to stimulate RANKL. Interleukin-6 mRNA and protein expression were also enhanced by A. actinomycetemcomitans, but Cdt had limited involvement in this enhancement.

    In conclusion, two distinct mechanisms by which A. actinomycetemcomitans Cdt may be involved in the pathogenesis of localized aggressive periodontitis are proposed. Firstly, the growth arrest of the resident fibroblasts may impair the physiological connective tissue remodelling equilibrium and lead to connective tissue attachment loss. Secondly, the induction of RANKL by these cells, residing in the proximity of the alveolar bone, may locally stimulate osteoclastogenesis and promote alveolar bone resorption. This work also provides further insights to the understanding of Cdt mechanisms of action, contributing to the global characterization of the toxin’s virulence.

  • 5.
    Belibasakis, Georgios N
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Wang, Y
    Chen, C
    Kalfas, S
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    The cytolethal distending toxin induces receptor activator of NF-κB ligand expression in human gingival fibroblasts and periodontal ligament cells2005Inngår i: Infection and Immunity, ISSN 0019-9567, Vol. 73, nr 1, 342-351 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Actinobacillus actinomycetemcomitans is associated with localized aggressive periodontitis, a disease characterized by rapid loss of the alveolar bone surrounding the teeth. Receptor activator of NF-kappaB Ligand (RANKL) and osteoprotegerin (OPG) are two molecules that regulate osteoclast formation and bone resorption. RANKL induces osteoclast differentiation and activation, whereas OPG blocks this process by acting as a decoy receptor for RANKL. The purpose of this study was to investigate the effect of A. actinomycetemcomitans on the expression of RANKL and OPG in human gingival fibroblasts and periodontal ligament cells. RANKL mRNA expression was induced in both cell types challenged by A. actinomycetemcomitans extract, whereas OPG mRNA expression remained unaffected. Cell surface RANKL protein was also induced by A. actinomycetemcomitans, whereas there was no change in OPG protein secretion. A cytolethal distending toxin (Cdt) gene-knockout strain of A. actinomycetemcomitans did not induce RANKL expression, in contrast to its wild-type strain. Purified Cdt from Haemophilus ducreyi alone, or in combination with extract from the A. actinomycetemcomitans cdt mutant strain, induced RANKL expression. Pretreatment of A. actinomycetemcomitans wild-type extract with Cdt antiserum abolished RANKL expression. In conclusion, A. actinomycetemcomitans induces RANKL expression in periodontal connective tissue cells. Cdt is crucial for this induction and may therefore be involved in the pathological bone resorption during the process of localized aggressive periodontitis.

  • 6.
    Belibasakis, Georgios N
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Wang, Y
    Chen, C
    Lagergård, T
    Kalfas, S
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Cytokine responses of human gingival fibroblasts to Actinobacillus actinomycetemcomitans cytolethal distending toxin2005Inngår i: Cytokine, ISSN 1043-4666, Vol. 30, nr 2, 56-63 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Actinobacillus actinomycetemcomitans is implicated in the pathogenesis of localized aggressive periodontitis, and has the capacity to express a cytolethal distending toxin (Cdt). Gingival fibroblasts (GF) are resident cells of the periodontium, which can express several osteolytic cytokines. The aims of this study were a) to investigate the role of Cdt in A. actinomycetemcomitans-induced expression of osteolytic cytokines and their cognate receptors in GF and b) to determine if the previously demonstrated induction of receptor activator of NFkappaB ligand (RANKL) by A. actinomycetemcomitans is mediated by these pro-inflammatory cytokines or by prostaglandin E(2) (PGE(2)). A. actinomycetemcomitans clearly induced interleukin (IL)-6, IL-1beta, and to a minimal extent, tumor necrosis factor (TNF)-alpha mRNA expression. At the protein level, IL-6 but not IL-1beta or TNF-alpha expression was stimulated. The mRNA expression of the different receptor subtypes recognizing IL-6, IL-1beta and TNF-alpha was not affected. A cdt-knockout strain of A. actinomycetemcomitans had similar effects on cytokine and cytokine receptor mRNA expression, compared to its parental wild-type strain. Purified Cdt stimulated IL-6, but not IL-1beta or TNF-alpha protein biosynthesis. Antibodies neutralizing IL-6, IL-1 or TNF-alpha, and the PGE(2) synthesis inhibitor indomethacin, did not affect A. actinomycetemcomitans-induced RANKL expression. In conclusion, a) A. actinomycetemcomitans induces IL-6 production in GF by a mechanism largely independent of its Cdt and b) A. actinomycetemcomitans-induced RANKL expression in GF occurs independently of IL-1, IL-6, TNF-alpha, or PGE(2).

  • 7.
    Belibasakis, Georgios N
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Mattsson, Anna
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Wang, Ying
    Chen, Casey
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Cell cycle arrest of human gingival fibroblasts and periodontal ligament cells by Actinobacillus actinomycetemcomitans: involvement of the cytolethal distending toxin2004Inngår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), ISSN 0903-4641, Vol. 112, nr 10, 674-685 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The cytolethal distending toxin (Cdt) is produced by several Gram-negative bacterial species and causes growth arrest and morphological alterations in mammalian cells. Actinobacillus actinomycetemcomitans, which is involved in the pathogenesis of localized aggressive periodontitis, also produces a Cdt that affects periodontal connective tissue cells. The aim of this study was to investigate in which phase of the cell cycle these cells are arrested and enlarged when challenged with A. actinomycetemcomitans, and to evaluate the involvement of its Cdt. Human gingival fibroblasts and periodontal ligament cells were challenged with A. actinomycetemcomitans extract, or with purified Cdt, and cell cycle analysis was performed by propidium iodide staining and flow cytometry. Cells exposed to an A. actinomycetemcomitans wild-type strain, or to purified Cdt, were arrested in both G1 and G2/M phases, and appeared enlarged compared to the corresponding controls. The cellular enlargement occurred in both G1 and G2/M arrested cells. In contrast, cells exposed to an A. actinomycetemcomitans cdt-knockout mutant strain showed cell cycle phase distribution and size similar to the controls. In conclusion, A. actinomycetemcomitans causes a combined G1 and G2/M growth arrest and enlargement in periodontal connective tissue cells, which is attributed to its Cdt.

  • 8. Brage, M
    et al.
    Abrahamson, M
    Lindström, V
    Grubb, A
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Different cysteine proteinases involved in bone resorption and osteoclast formation.2005Inngår i: Calcified Tissue International, ISSN 0171-967X, Vol. 76, nr 6, 439-447 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cysteine proteinases, especially cathepsin K, play an important role in osteoclastic degradation of bone matrix proteins and the process can, consequently, be significantly inhibited by cysteine proteinase inhibitors. We have recently reported that cystatin C and other cysteine proteinase inhibitors also reduce osteoclast formation. However, it is not known which cysteine proteinase(s) are involved in osteoclast differentiation. In the present study, we compared the relative potencies of cystatins C and D as inhibitors of bone resorption in cultured mouse calvariae, osteoclastogenesis in mouse bone marrow cultures, and cathepsin K activity. Inhibition of cathepsin K activity was assessed by determining equilibrium constants for inhibitor complexes in fluorogenic substrate assays. The data demonstrate that whereas human cystatins C and D are equipotent as inhibitors of bone resorption, cystatin D is 10-fold less potent as an inhibitor of osteoclastogenesis and 200-fold less potent as an inhibitor of cathepsin K activity. A recombinant human cystatin C variant with Gly substitutions for residues Arg8, Leu9, Val10, and Trp106 did not inhibit bone resorption, had 1,000-fold decreased inhibitory effect on cathepsin K activity compared to wildtype cystatin C, but was equipotent with wildtype cystatin C as an inhibitor of osteoclastogenesis. It is concluded that (i) different cysteine proteinases are likely to be involved in bone resorption and osteoclast formation, (ii) cathepsin K may not be an exclusive target enzyme in any of the two systems, and (iii) the enzyme(s) involved in osteoclastogenesis might not be a typical papain-like cysteine proteinase.

  • 9. Brage, M
    et al.
    Lie, Anita
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Ransjö, Maria
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Kasprzykowski, F
    Kasprzykowska, R
    Abrahamson, M
    Grubb, A
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Osteoclastogenesis is decreased by cysteine proteinase inhibitors2004Inngår i: Bone, ISSN 8756-3282, Vol. 34, nr 3, 412-24 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of cystatin C and other cysteine proteinase inhibitors on osteoclast formation and differentiation have been investigated. Cystatin C decreased osteoclast formation stimulated by parathyroid hormone (PTH), 1,25(OH)2-vitamin D3 or interleukin-6 (IL-6) (in the presence of its soluble receptor) as assessed by the number of tartrate-resistant acid phosphatase (TRAP+) multinucleated cells in mouse bone marrow cultures. The inhibitory effect was associated with decreased mRNA expression for the calcitonin receptor as well as decreased number of specific binding sites for 125I-calcitonin, and without any effect on the mRNA expression of receptor activator of nuclear factor kappaB (NF-kappaB) ligand (RANKL). Similarly, the cysteine proteinase inhibitors leupeptin, E-64 and benzyloxycarbonyl-Phe-Ala-diazomethane (Z-FA-CHN2) decreased PTH-stimulated formation of TRAP+ multinucleated cells and binding of 125I-calcitonin. A peptidyl derivative synthesized to mimic part of the proteinase-binding site of cystatin C (benzyloxycarbonyl-Arg-Leu-Val-Gly-diazomethane, or Z-RLVG-CHN2) also decreased PTH-stimulated osteoclast formation. In a 9-day culture, addition of cystatin C during the last 5 days was sufficient to cause substantial inhibition of osteoclast formation. Cystatin C-induced decrease of osteoclast formation was associated with enhanced number of F4/80-positive macrophages and increased mRNA expression of the macrophage receptor c-fms in the bone marrow culture. Osteoclast formation in mouse bone marrow cultures as well as in mouse spleen cell cultures, stimulated by macrophage colony-stimulating factor (M-CSF) and RANKL was also decreased by different cysteine proteinase inhibitors. In addition, cystatin C inhibited M-CSF/RANKL induction of calcitonin receptor mRNA in spleen cell cultures. The inhibitory effect by cystatin C in spleen cells was associated with decreased mRNA expression of RANK and the transcription factor NFAT2. It is concluded that cysteine proteinase inhibitors decrease formation of osteoclasts by interfering at a late stage of pre-osteoclast differentiation.

  • 10. Brand, HS
    et al.
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Grubb, A
    Beertsen, W
    Nieuw Amerongen, AV
    Everts, V
    Family 2 cystatins inhibit osteoclast-mediated bone resorption in calvarial bone explants.2004Inngår i: Bone, ISSN 8756-3282, Vol. 35, nr 3, 689-696 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Osteoclastic bone resorption depends on the activity of various proteolytic enzymes, in particular those belonging to the group of cysteine proteinases. Biochemical studies have shown that cystatins, naturally occurring inhibitors of these enzymes, inhibit bone matrix degradation. Since the mechanism by which cystatins exert this inhibitory effect is not completely resolved yet, we studied the effect of cystatins on bone resorption microscopically and by Ca-release measurements. Calvarial bone explants were cultured in the presence or absence of family 2 cystatins and processed for light and electron microscopic analysis, and the culture media were analyzed for calcium release. Both egg white cystatin and human cystatin C decreased calcium release into the medium significantly. Microscopic analyses of the bone explants demonstrated that in the presence of either inhibitor, a high percentage of osteoclasts was associated with demineralized non-degraded bone matrix. Following a 24-h incubation in the presence of cystatin C, 41% of the cells were adjacent to areas of demineralized non-degraded bone matrix, whereas in controls, this was only 6%. If bone explants were cultured with both PTH and cystatin C, 60% of the osteoclasts were associated with demineralized non-degraded bone matrix, compared to 27% for bones treated with PTH only (P < 0.01). Our study provides evidence that cystatins, the naturally occurring inhibitors of cysteine proteinases, reversibly inhibit bone matrix degradation in the resorption lacunae adjacent to osteoclasts. These findings suggest the involvement of cystatins in the modulation of osteoclastic bone degradation.

  • 11.
    Brechter, Anna Bernhold
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Persson, Emma
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Lundgren, Inger
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Lerner, Ulf H
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Kinin B1 and B2 receptor expression in osteoblasts and fibroblasts is enhanced by interleukin-1 and tumour necrosis factor-alpha. Effects dependent on activation of NF-kappaB and MAP kinases.2008Inngår i: Bone, ISSN 8756-3282, E-ISSN 1873-2763, Vol. 43, nr 1, 72-83 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Pro-inflammatory mediators formed by the kallikrein-kinin system can stimulate bone resorption and synergistically potentiate bone resorption induced by IL-1 and TNF-alpha. We have shown that the effect is associated with synergistically enhanced RANKL expression and enhanced prostaglandin biosynthesis, due to increased cyclooxygenase-2 expression. In the present study, the effects of osteotropic cytokines and different kinins on the expression of receptor subtypes for bradykinin (BK), des-Arg10-Lys-BK (DALBK), IL-1beta and TNF-alpha have been investigated. IL-1beta and TNF-alpha enhanced kinin B1 and B2 receptor binding in the human osteoblastic cell line MG-63 and the mRNA expression of B1 and B2 receptors in MG-63 cells, human gingival fibroblasts and intact mouse calvarial bones. Kinins did not affect mRNA expression of IL-1 or TNF receptors. EMSA showed that IL-1beta and TNF-alpha activated NF-kappaB and AP-1 in MG-63 cells. IL-1beta stimulated NF-kappaB via a non-canonical pathway (p52/p65) and TNF-alpha via the canonical pathway (p50/p65). Activation of AP-1 involved c-Jun in both IL-1beta and TNF-alpha stimulated cells, but c-Fos only in TNF-alpha stimulated cells. Phospho-ELISA and Western blots showed that IL-1beta activated JNK and p38, but not ERK 1/2 MAP kinase. Pharmacological inhibitors showed that NF-kappaB, p38 and JNK were important for IL-1beta induced stimulation of B1 receptors, and NF-kappaB and p38 for B2 receptors. p38 and JNK were important for TNF-alpha induced stimulation of B1 receptors, whereas NF-kappaB, p38 and JNK were involved in TNF-alpha induced expression of B2 receptors. These data show that IL-1beta and TNF-alpha upregulate B1 and B2 receptor expression by mechanisms involving activation of both NF-kappaB and MAP kinase pathways, but that signal transduction pathways are different for IL-1beta and TNF-alpha. The enhanced kinin receptor expression induced by the pro-inflammatory cytokines IL-1beta and TNF-alpha might be one important mechanism involved in the synergistic enhancement of prostaglandin formation caused by co-treatment with kinins and one of the two cytokines. These mechanisms might help to explain the enhanced bone resorption associated with inflammatory disorders, including periodontitis and rheumatoid arthritis.

  • 12.
    Brechter, Anna
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Bradykinin potentiates cytokine-induced prostaglandin biosynthesis in osteoblasts by enhanced expression of cyclooxygenase 2, resulting in increased RANKL expression2007Inngår i: Arthritis and Rheumatism, ISSN 0004-3591, Vol. 56, nr 3, 910-923 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE: Bradykinin (BK) stimulates bone resorption in vitro and synergistically potentiates interleukin-1 (IL-1)-induced bone resorption and prostaglandin (PG) formation, suggesting that kinins are important in inflammation-induced bone loss. The present study was undertaken to study 1) the role of the kinin B1 and B2 receptors in the synergistic interaction with IL-1 and tumor necrosis factor alpha (TNFalpha), 2) the molecular mechanisms involved in synergistic enhancement of PG formation, and 3) the effects of kinins on cytokine-induced expression of RANKL, RANK, and osteoprotegerin (OPG) (the latter being crucial molecules in osteoclast differentiation). METHODS: Formation of PGs, expression of enzymes involved in arachidonic acid metabolism, and expression of RANKL, RANK, and OPG were assessed in the human osteoblastic cell line MG-63 and in mouse calvarial bones. The role of NF-kappaB and MAP kinases was studied using pharmacologic inhibitors. RESULTS: PGE(2) formation and cyclooxygenase 2 (COX-2) protein expression were induced by IL-1beta and potentiated by kinins with affinity for the B1 or B2 receptors, resulting in PGE(2)-dependent enhancement of RANKL. The enhancements of PGE(2) formation and COX-2 were markedly decreased by inhibition of p38 and JNK MAP kinases, whereas inhibition of NF-kappaB resulted in abolishment of the PGE(2) response with only slight inhibition of COX-2. CONCLUSION: Kinin B1 and B2 receptors synergistically potentiate IL-1- and TNFalpha-induced PG biosynthesis in osteoblasts by a mechanism involving increased levels of COX-2, resulting in increased RANKL. The synergistic stimulation is dependent on NF-kappaB and MAP kinases. These mechanisms might help to explain the enhanced bone resorption associated with inflammatory disorders, including that in rheumatoid arthritis.

  • 13. Conaway, H Herschel
    et al.
    Persson, Emma
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Halén, Marie
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Granholm, Susanne
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Svensson, Olle
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Pettersson, Ulrika
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk farmakologi.
    Lie, Anita
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Lerner, Ulf H
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Retinoids inhibit differentiation of hematopoietic osteoclast progenitors2009Inngår i: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 23, nr 10, 3526-3538 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Whether vitamin A promotes skeletal fragility, has no effect on fracture rate, or protects against bone loss is unclear. In the present study, effects of retinoids on osteoclast differentiation in cultured mouse bone marrow cells (BMCs), bone marrow macrophages (BMMs), spleen cells, and RAW264.7 cells were evaluated by analyzing osteoclast formation and expression of genes important in signal transduction and osteoclast function. All-trans-retinoic acid (ATRA) did not stimulate osteoclastogenesis in BMCs, but inhibited hormone and RANKL-induced gene expression and formation of osteoclasts. In BMMs, spleen cells, and RAW264.7 cells, osteoclast differentiation and formation stimulated by M-CSF/RANKL were inhibited (IC(50) = 0.3 nM) by ATRA. The effect was exerted at an early step of RANKL-induced differentiation. ATRA also abolished increases of the transcription factors c-Fos and NFAT2 stimulated by RANKL and suppressed down-regulation of the antiosteoclastogenic transcription factor MafB. By comparing effects of several compounds structurally related to ATRA, as well as by using receptor antagonists, evaluation pointed to inhibition being mediated by RARalpha, with no involvement of PPARbeta/delta. The results suggest that activation of RARalpha by retinoids in myeloid hematopoietic precursor cells decreases osteoclast formation by altering expression of the transcription factors c-Fos, NFAT2, and MafB.

  • 14.
    Granholm, Susanne
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Lundberg, Pernilla
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Calcitonin inhibits osteoclast formation in mouse haematopoetic cells independently of transcriptional regulation by receptor activator of NF-{kappa}B and c-Fms2007Inngår i: The Journal of Endocrinology, ISSN 1479-6805, Vol. 195, nr 3, 415-427 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of calcitonin (CT) on osteoclast formation and gene expression have been studied in cultured mouse spleen cells and mouse bone marrow macrophages (BMMs). CT inhibited the formation of multinucleated osteoclasts and resorption pits in spleen cell cultures and BMM as well as in CD115(+) CD3(-) CD45R(-)sorted BMM cultures, incubated in the presence of macrophage colony-stimulating factor and receptor activator of NF-kappaB ligand (RANKL). No effect on apoptosis by CT was observed. CT did not affect the mRNA expressions of RANK and c-Fms, or the mRNA expressions of a wide variety of transcription factors and genes important for osteoclast differentiation and activity. CT induced inhibition of tartrate-resistant acid phosphatase (TRAP), positive multinucleated osteoclast formation was not associated with any decrease of total TRAP activity, resulting in a large number of TRAP(+) mononucleated cells in CT-treated cultures. CT did not affect the mRNA expression of dendritic cell-specific transmembrane protein, d2 isoform of vacuolar (H(+)) ATPase v(o) domain, a disintegrin and metalloproteinase domain 8 (ADAM8), ADAM12, DNAX-activating protein or Fc receptor common gamma chain suggested to be involved in fusion of mononucleated osteoclast progenitor cells. The inhibitory effect by CT was mimicked not only by compounds activating cAMP and protein kinase A (PKA) but also by a cAMP analogue activating the exchange protein directly activated by cAMP (Epac) pathway. It is concluded that CT, through cAMP/PKA/Epac cascades, inhibits osteoclast formation and that this effect is not associated with decreased transcription of genes known to be important for osteoclast progenitor cell differentiation, fusion or function.

  • 15.
    Granholm, Susanne
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Lundberg, Pernilla
    Lerner, Ulf H
    Expression of the calcitonin receptor, calcitonin receptor-like receptor, and receptor activity modifying proteins during osteoclast differentiation.2008Inngår i: Journal of cellular biochemistry, ISSN 1097-4644, Vol. 104, nr 3, 920-933 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The expressions of the calcitonin receptor (CTR), the calcitonin receptor-like receptor (CLR), the receptor activity-modifying proteins (RAMP) 1-3, and of the receptor component protein (RCP) have been studied in mouse bone marrow macrophages (BMM) during osteoclast differentiation, induced by treatment with M-CSF and RANKL. Analyses of mRNA showed that CLR and RAMP1-3, but not CTR, were expressed in M-CSF stimulated BMM. RANKL gradually increased CTR mRNA, transiently enhanced CLR and transiently decreased RAMP1 mRNA, but did not affect RAMP2, RAMP3, or RCP mRNA. However, RANKL did not affect protein levels of CLR or RAMP1-3 as assessed by Western blots or FACS analyses, whereas immunocytochemistry showed enhanced CTR protein. Analyses of cAMP production showed that BMM cells expressed functional receptors for calcitonin gene-related peptide (CGRP), amylin, adrenomedullin, and intermedin, but not for calcitonin and calcitonin receptor stimulating peptide (CRSP), but that RANKL induced the expression of receptors for calcitonin and CRSP as well. Calcitonin, CGRP, amylin, adrenomedullin, intermedin, and CRSP all down regulated the CTR mRNA, but none of the peptides caused any effects on the expression of CLR or any of the RAMPs. Our data show that BMM cells express receptors for CGRP, amylin, adrenomedullin, and intermedin and that RANKL induces the formation of receptors for calcitonin and CRSP in these cells. We also show, for the first time, that the CTR is not only down regulated by signaling through the CTR but also by the peptides signaling through CLR/RAMPs.

  • 16. Holmberg, Anders R
    et al.
    Lerner, Ulf H
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Alayia, Ayodele A
    Al-Mohanna, Mai
    Adra, Chaker
    Marquez, Marcela
    Meurling, Lennart
    Nilsson, Sten
    Development of a novel poly bisphosphonate conjugate for treatment of skeletal metastasis and osteoporosis2010Inngår i: International Journal of Oncology, ISSN 1019-6439, Vol. 37, nr 3, 563-567 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Advanced stage prostate and breast cancer frequently metastasize to the skeleton (approximately 75%). An additional complication in these patients, that further affects the bones, is that their hormonal treatment, induces osteoporosis. Bisphosphonates (bpns) are standard drugs against osteoporosis and have been shown to have clinically significant anti-tumor effects. This study describes the development of a new polybisphosphonate conjugate (ODX) with enhanced dual efficacy i.e. with anti-bone resorption and anti-tumor properties. Zoledronic acid (Zometa) was used as a positive control (at equimolar concentrations). Alendronic acid and aminoguanidine were conjugated to oxidized dextran with subsequent reductive amination (on average approximately 8 alendronate and approximately 50 guanidine moieties per conjugate). ODX was tested in a bone resorption assay for its capacity to inhibit bone resorbing osteoclasts (bone organ culture from neonatal mice, 45Ca labelled bone mineral). Tumor cell toxicity was studied on prostate (PC3) and breast cancer (MDA231, MDA453) cell cultures. Two methods were employed, a fluorescent cytotoxicity assay (FMCA) and an apoptosis assay (Annexin V assay). In the bone resorption assay, Zometa and ODX showed very similar potency with 50% osteoclast inhibition at approximately 20 nM and 100% at 0.2 microM. In the FMCA, IC50 for ODX was at approximately 2 microM and 25 microM for Zometa (PC3). In the apoptosis assay, ODX induced approximately 85-97% apoptosis at 10 microM in both cell lines, while Zometa failed to induce any significant apoptosis in any of the cell lines at the tested concentration range (10 nM-10 microM). ODX appears to be a promising drug candidate with high dual efficacy for the treatment of bone metastasis and osteoporosis. It has both potent osteoclast inhibiting properties and enhanced anti-tumor efficacy.

  • 17. Holmlund, A
    et al.
    Hänström, L
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Bone resorbing activity and cytokine levels in gingival crevicular fluid before and after treatment of periodontal disease.2004Inngår i: Journal of Clinical Periodontology, ISSN 0303-6979, Vol. 31, nr 6, 475-482 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: The aim of the present study was to investigate bone resorption activity (BRA), interleukin-1 alpha (IL-1 alpha), IL-1 beta and interleukin-1 receptor antagonist (IL-1ra) in gingival crevicular fluid (GCF) in sites with no signs of periodontal disease and in sites with horizontal or angular loss of periodontal bone. These assessments were performed before and after periodontal treatment. METHODS: GCFs were collected from 10 individuals with filter strips from two healthy sites and four sites with deep pathological periodontal pockets, two of which showed horizontal bone loss and two with angular bone loss. All diseased pockets were treated with flap surgery and systemic Doxyferm. Twelve months later GCF was collected again and treatment outcome evaluated. BRA in GCFs was assessed in a bone organ culture system by following the release of (45)Ca from neonatal mouse calvariae. The amounts of IL-1 alpha, IL-1 beta and IL-1ra in GCFs were quantified by enzyme-linked immunosorbent assay (ELISA). RESULTS: Treatment resulted in reduction of pocket depths with 3.5+/-0.5 mm in sites with angular bone loss and 2.8+/-0.3 mm in sites with horizontal bone loss. Initially, BRA, IL-1 alpha, IL-1 beta and IL-1ra were significantly higher in GCFs from diseased sites compared with healthy sites. No differences in BRA and cytokine levels were seen between GCFs from pockets with horizontal and angular bone losses. The levels of IL-1 alpha, IL-1 beta and IL-1ra were significantly reduced after treatment of diseased pockets. Pocket depths were significantly correlated to BRA only in pre-treatment sites with angular bone loss. BRA was correlated to Il-1 alpha, IL-1 beta, but not to IL-1ra, in diseased sites with angular bone loss, before and after treatment. The reductions of BRA in the individual sites, seen after treatment, were not correlated to the reductions of Il-1 alpha, IL-1 beta or IL-1ra. CONCLUSIONS: These data show that BRA and cytokine levels are increased in GCFs from sites with periodontal disease and that periodontal treatment results in reduction of the cytokines. Our findings further indicate that IL-1 alpha and IL-1 beta play important roles for the BRA present in GCFs, but that other factors also contribute to this activity.

  • 18. Holmlund, Anders
    et al.
    Hedin, Måns
    Pussinen, Pirkko J
    Lerner, Ulf H
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Lind, Lars
    Porphyromonas gingivalis (Pg) a possible link between impaired oral health and acute myocardial infarction2011Inngår i: International Journal of Cardiology, ISSN 0167-5273, E-ISSN 1874-1754, Vol. 148, nr 2, 148-153 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE: To investigate if oral health parameters were impaired in patients with myocardial infarction (MI) and if there was an association with serum antibody levels against the periodontal pathogens Porphyromonas gingivalis (Pg) and Aggregatibacter actinomycetemcomitans (Aa).

    METHODS: A case-control study consisting of 100 patients with MI and 100 age- and sex-matched controls from the same geographic area was investigated regarding oral health.

    RESULTS: The MI group had significantly more periodontal bone loss (PBL), number of deepened pockets (NDP), and bleeding on probing (BOP), and lower number of teeth (NT) than the controls. After adjustment for known cardiovascular risk factors NT, BOP, and NDP still remained significantly related to MI (p=0.014, p=0.02, and p=0.0069, respectively). IgG antibody levels against Pg were higher in subjects with MI (p=0.043), as well as in those with >4 deepened pockets (p=0.05), BOP>20% (p=0.001) and PBL (p=0.0003). However, indicating a causal pathway, the relationship between MI and Pg IgG disappeared when the oral parameters were included in the logistic regression model (p=0.69). No correlation was seen between MI and Aa in the present study.

    CONCLUSION: Patients with MI had an impaired oral health compared to controls. Furthermore, IgG levels against Pg were related to both MI and oral health, suggesting this pathogen as a possible link between oral health and CVD.

  • 19.
    Jonsson, Kent-Olov
    et al.
    Umeå universitet, Medicinsk fakultet, Farmakologi och klinisk neurovetenskap, Farmakologi.
    Persson, Emma
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Fowler, Christopher J
    Umeå universitet, Medicinsk fakultet, Farmakologi och klinisk neurovetenskap, Farmakologi.
    The cannabinoid CB2 receptor selective agonist JWH133 reduces mast cell oedema in response to compound 48/80 in vivo but not the release of beta-hexosaminidase from skin slices in vitro.2006Inngår i: Life Sciences, ISSN 0024-3205, Vol. 78, nr 6, 598-606 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In a recent study so far published in abstract form, it was reported that the CB(2) receptor selective agonist AM1241 diminishes oedema produced as a result of mast cell degranulation in vivo. It is, however, not known whether other structurally different CB(2) agonists share this effect, and whether this is due to a direct effect on mast cell function. In the present study, we have investigated the effects of JWH133, a CB(2) receptor selective agonist, together with the anti-inflammatory agent palmitoylethanolamide and its analogue palmitoylisopropylamide, on compound 48/80-induced oedema and degranulation in vivo and in vitro. JWH133 (20 and 200 microg/mouse i.p.) significantly reduced the ability of compound 48/80 to induce oedema in vivo in the anaesthetised mouse following its injection into the ear pinna. Palmitoylethanolamide (200 microg/mouse i.p) also reduced the response to compound 48/80, whereas no firm conclusions could be drawn for palmitoylisopropylamide (20 and 200 microg/mouse i.p.). The CB(2) selective antagonist/inverse agonist SR144528 (60 microg/mouse i.p.) appeared to produce anti-inflammatory effects per se in this model, making it hard to interpret the effects of JWH133 in terms of CB(2) receptor mediated activation. In contrast to the situation in vivo, neither JWH133 (0.3 and 3 microM) nor palmitoylethanolamide (10 microM) affected mast cell degranulation, measured by following the release of the granular protein beta-hexosaminidase, produced by compound 48/80 in vitro in mouse skin slices. The two compounds were also ineffective in inhibiting the binding of [(3)H]pyrilamine to histamine H(1) receptors in vitro. It is concluded that the ability of JWH133 to affect mast cell dependent inflammation in vivo may be mediated by an indirect action upon the mast cells.

  • 20. Kaneko, H
    et al.
    Mehrotra, M
    Alander, C
    Lerner, Ulf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Pilbeam, C
    Raisz, L
    Effects of prostaglandin E-2 and lipopolysaccharide on osteoclastogenesis in RAW 264.7 cells2007Inngår i: Prostaglandins, Leukotrienes and Essential Fatty Acids, ISSN 0952-3278, E-ISSN 1532-2823, Vol. 77, nr 3-4, 181-186 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Introduction: Prostaglandins (PGs) can act on both hematopoietic and osteoblastic lineages to enhance osteoclast formation.

    Methods: We examined PGE(2) stimulated osteoclastogenesis in RAW 264.7 cells and the role of endogenous PGE2 in lipopolysaccharide (LPS) stimulated osteoclastogenesis.

    Results: RANKL (1-100ng/ml) increased formation of osteoclasts, defined as tartrate resistant acid phosphatase multinucleated cells, with peak effects at 30 ng/ml. Addition of PGE2 (0-01-1.0 mu M) to RANKL (30 ng/ml) dose dependently increased osteoclast number 30-150%. Use of NS-398 (0.1 mu M) or indomethacin (Indo, 1.0 mu M) to block endogenous PG synthesis had little effect on the response to RANKL alone but significantly decreased the response to PGE2. Addition of LPS (100 ng/ml) to RANKL increased osteoclast number 50%, and this response was significantly decreased by NS-398 and Indo. RANKL and PGE2 produced small, additive increases in COX-2 mRNA levels, while LPS produced a larger increase. PG release into the medium was not increased by RANKL and PGE2 but markedly increased by LPS.

    Conclusion: We conclude that RANKL stimulated osteoclastogenesis can be enhanced by PGE2 and LPS though direct effects on the hematopoietic cell lineage and that these effects may be mediated in part by induction of COX-2 and enhanced intracellular PG production.

  • 21.
    Kelk, Peyman
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Claesson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Hänström, L
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Lerner, Ulf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Kalfas, S
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Abundant secretion of bioactive interleukin-1beta by human macrophages induced by Actinobacillus actinomycetemcomitans leukotoxin2005Inngår i: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 73, nr 1, 453-458 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Actinobacillus actinomycetemcomitans produces a leukotoxin that selectively kills human leukocytes. Recently, we reported that macrophages are highly sensitive to leukotoxin and that their lysis involves activation of caspase 1. In this study, we show that leukotoxin also induces the production and release of proinflammatory cytokines from human macrophages. The macrophages were challenged with leukotoxin or lipopolysaccharide (LPS) from A. actinomycetemcomitans or LPS from Escherichia coli, and the production and secretion of interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor alpha (TNF-alpha) were determined at the mRNA and protein levels by reverse transcription-PCR and enzyme-linked immunosorbent assay, respectively. Leukotoxin (1 to 30 ng/ml) induced abundant production and secretion of IL-1beta, while the effects on IL-6 and TNF-alpha production were limited. Leukotoxin (1 ng/ml) caused a 10-times-higher release of IL-1beta than did LPS (100 ng/ml). The secreted IL-1beta was mainly the bioactive 17-kDa protein. At higher concentrations (>30 ng/ml), leukotoxin caused secretion of mainly inactive cytokine, the 31-kDa pro-IL-1beta. The presence of specific antibodies to IL-1beta or of a caspase 1 inhibitor blocked the secretion and production of the cytokine. Supernatants of leukotoxin-challenged macrophages stimulated bone resorption when tested in a mouse calvarial model. The activity could be blocked by an IL-1 receptor antagonist or specific antibodies to IL-1beta. We concluded that A. actinomycetemcomitans leukotoxin can trigger abundant production and secretion of bioactive IL-1beta by human macrophages, which is mediated by activation of caspase 1.

  • 22.
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Bone Remodeling in Post-menopausal Osteoporosis.2006Inngår i: Journal of Dental Research, ISSN 0022-0345, Vol. 85, nr 7, 584-595 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bone mass in the skeleton is dependent on the coordinated activities of bone-forming osteoblasts and bone-resorbing osteoclasts in discrete bone multi-cellular units. Remodeling of bone in these units is important not only for maintaining bone mass, but also to repair microdamage, to prevent accumulation of too much old bone, and for mineral homeostasis. The activities of osteoblasts and osteoclasts are controlled by a variety of hormones and cytokines, as well as by mechanical loading. Most importantly, sex hormones are very crucial for keeping bone mass in balance, and the lack of either estrogen or testosterone leads to decreased bone mass and increased risk for osteoporosis. The prevalence of osteoporotic fractures is increasing dramatically in the Western part of the world and is a major health problem in many countries. In the present review, the cellular and molecular mechanisms controlling bone remodeling and the influence of sex hormones on these processes are summarized. In a separate paper in this issue, the pathogenesis of post-menopausal osteoporosis will be compared with that of inflammation-induced bone remodeling, including the evidence for and against the hypothesis that concomitant post-menopausal osteoporotic disease influences the progression of periodontal disease.

  • 23.
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Deletions of genes encoding calcitonin/alpha-CGRP, amylin and calcitonin receptor have given new and unexpected insights into the function of calcitonin receptors and calcitonin receptor-like receptors in bone.2006Inngår i: Journal of Musculoskeletal & Neuronal Interactions, Vol. 6, nr 1, 87-95 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It has been suggested that skeletal nerves fibers may play important roles in neuro-osteogenic interactions. This view is partly based upon information obtained from immunohistochemical studies, chemical and surgical denervation experiments and clinical observations in patients with stroke and spinal cord injury, indicating the presence of a network of nerve fibers in the skeleton and that defective signalling in skeletal nerve fibers affects remodelling of bone. This view is also supported by data showing that functional receptors for signalling molecules in skeletal nerve fibers are expressed in bone cells and that activation of these receptors leads to profound effects on bone forming osteoblasts and bone resorbing osteoclasts. Convincing evidence for a role of neuronal signalling in bone metabolism has been provided by gene deletion approaches in which it has been shown that leptin-sensitive and neuropeptide Y-sensitive receptors in hypothalamus are important for bone remodelling in mice. Recently, gene deletion experiments have shown that calcitonin gene-related peptide (CGRP), one of the neuropeptides present in skeletal nerve fibers, is an important physiological regulator of bone formation at the level of osteoblast activity. CGRP belongs to the calcitonin (CT) family of peptides also including CT, amylin and adrenomedullin, as well as the recently described intermedin and calcitonin receptor-stimulating peptide. These peptides utilize two seven transmembrane G protein-coupled receptors - the calcitonin receptor (CTR) and the calcitonin receptor- like receptor (CRLR) - which can dimerize with three different single transmembrane proteins, making up the RAMP family. Associations between RAMPs and either CTR or CRLR give rise to seven distinct, molecularly characterized, receptors for CT, CGRP, amylin and adrenomedullin. Deletions of the genes for ligands in the CT family of peptides and for one of the receptors have revealed unexpected findings that have changed our view on the role of these peptides in bone remodelling. It was anticipated that deletions of the CT/alpha-CGRP and CTR genes would lead to bone loss, since CT has been shown to inhibit bone resorption in vitro and in vivo and has been used to treat patients with excessive bone resorption. Surprisingly, it was found that CT/alpha-CGRP-/- and CTR+/- mice have increased bone mass due to increased bone formation. Mice with deletion of the amylin gene, however, exhibited bone loss due to enhanced bone resorption. Selective deletion of the alpha-CGRP gene also leads to bone loss, but due to decreased bone formation. Thus, our understanding of the role of the CT family of peptides has been changed dramatically and much more data have to be gained before we fully understand the roles these peptides have in bone biology.

  • 24.
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Inflammation-induced Bone Remodeling in Periodontal Disease and the Influence of Post-menopausal Osteoporosis.2006Inngår i: Journal of Dental Research, ISSN 0022-0345, Vol. 85, nr 7, 596-607 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    During physiological conditions, the skeleton is remodeled in so-called bone multi-cellular units. Such units have been estimated to exist at 1-2 x 10(6) sites in the adult skeleton. The number and activities of these units are regulated by a variety of hormones and cytokines. In post-menopausal osteoporosis, lack of estrogen leads to increased numbers of bone multi-cellular units and to uncoupling of bone formation and bone resorption, resulting in too little bone laid down by osteoblasts compared with the amount of bone resorbed by osteoclasts. Inflammatory processes in the vicinity of the skeleton, e.g., marginal and apical periodontitis, will affect the remodeling of the nearby bone tissue in such a way that, in most patients, the amount of bone resorbed exceeds that being formed, resulting in net bone loss (inflammation-induced osteolysis). In some patients, however, inflammation-induced bone formation exceeds resorption, and a sclerotic lesion will develop. The cellular and molecular pathogenetic mechanisms in inflammation-induced osteolysis and sclerosis are discussed in the present review. The cytokines believed to be involved in inflammation-induced remodeling are very similar to those suggested to play crucial roles in post-menopausal osteoporosis. In patients with periodontal disease and concomitant post-menopausal osteoporosis, the possibility exists that the lack of estrogen influences the activities of bone cells and immune cells in such a way that the progression of alveolar bone loss will be enhanced. In the present paper, the evidence for and against this hypothesis is presented.

  • 25.
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Skelettet i käkar och annorstädes – en benhård vävnad fylld av liv och rörelse både vid hälsa och sjukdom. III. Obalancerad benremodellering orsakar osteoporossjukdom.2006Inngår i: Tandläkartidningen, ISSN 0039-6982, nr 98, 50-61 s.Artikkel i tidsskrift (Annet vitenskapelig)
  • 26.
    Lerner, Ulf H
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    New molecules in the tumor necrosis factor ligand and receptor superfamilies with importance for physiological and pathological bone resorption2004Inngår i: Critical Reviews in Oral Biology and Medicine, ISSN 1045-4411, E-ISSN 1544-1113, Vol. 15, nr 2, 64-81 s.Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Osteoclasts are tissue-specific polykaryon bone-resorbing cells derived from the monocyte/macrophage hematopoietic lineage with specialized functions required for the adhesion of the cells to bone and the subsequent polarization of the cell membrane, secretion of acid to dissolve mineral crystals, and release of proteolytic enzymes to degrade the extracellular matrix proteins. Most pathological conditions in the skeleton lead to loss of bone due to excess osteoclastic bone resorption, including periodontal disease, rheumatoid arthritis, and osteoporosis. In rare cases, most of them genetic, patients with osteopetrosis exhibit sclerotic bone due either to a lack of osteoclasts or to non-functional osteoclasts. Mainly because of phenotypic findings in genetically manipulated mice or due to spontaneous mutations in humans, mice, and rats, several genes have been discovered as being crucial for osteoclast formation and activation. Recent breakthroughs in our understanding of osteoclast biology have revealed the critical roles in osteoclast differentiation played by RANKL, RANK, and OPG, three novel members of the tumor necrosis factor ligand and receptor superfamilies. The further study of these molecules and downstream signaling events are likely to provide a molecular basis for the development of new drugs for the treatment of diseases with excess or deficient osteoclastic bone resorption.

  • 27.
    Lerner, Ulf H
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Persson, Emma
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Osteotropic effects by the neuropeptides calcitonin gene-related peptide, substance P and vasoactive intestinal peptide2008Inngår i: Journal of Musculoskeletal and Neuronal Interactions - JMNI, ISSN 1108-7161, Vol. 8, nr 2, 154-165 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Immunohistochemical phenotypic characterization of skeletal nerve fibers has demonstrated the expression of a restricted number of neuropeptides, including calcitonin gene-related peptide (CGRP), substance P (SP) and vasoactive intestinal peptide (VIP). According to the neuro-osteological hypothesis, such neuropeptides can be released and exert paracrine biological effects on bone cells present close to the nerve endings expressing these signaling molecules. The existence of such interplay is most convincingly shown by the hypothalamic control of bone formation, in the case of leptin stimulation of hypothalamic nuclei mediated by the sympathetic nervous system and inhibitory beta-adrenergic receptors on osteoblasts. In addition to these receptors, osteoblasts and osteoclasts express functional receptors for CGRP, SP and VIP, which can regulate both bone formation and bone resorption. The evidence for these observations is summarized in the present paper.

  • 28.
    Lerner, Ulf H
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Persson, Emma
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Lundberg, Pernilla
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Kinins and Neuro-osteogenic Factors2008Inngår i: Principles of Bone Biology 3rd Edition / [ed] John P. Bilezikian, Lawrence G. Raisz and T. John Martin, Amsterdam: Elsevier, 2008, 1025-1057 s.Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 29.
    Lerner, Ulf
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Ljunggren, O
    Benvävnadens omsättning. Mekanismer som förklarar uppkomsten av benskörhet och som möjliggör farmakologisk behandling.2006Inngår i: Läkartidningen, ISSN 0023-7205, Vol. 103, nr 40, 2972-2975 s.Artikkel i tidsskrift (Annet vitenskapelig)
  • 30. Liu, Yen-Chun G
    et al.
    Lerner, Ulf H
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Teng, Yen-Tung A
    Cytokine responses against periodontal infection: protective and destructive roles2010Inngår i: Periodontology 2000, ISSN 0906-6713, E-ISSN 1600-0757, Vol. 52, nr 1, 163-206 s.Artikkel i tidsskrift (Fagfellevurdert)
  • 31.
    Lundberg, Pernilla
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Allison, SJ
    Lee, NJ
    Baldock, PA
    Brouard, N
    Rost, S
    Enriquez, RF
    Sainsbury, A
    Lamghari, M
    Simmons, P
    Eisman, JA
    Gardiner, EM
    Herzog, H
    Greater bone formation of Y2 knockout mice is associated with increased osteoprogenitor numbers and altered Y1 receptor expression.2007Inngår i: Journal of Biological Chemistry, ISSN 0021-9258, Vol. 282, nr 26, 19082-19091 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Germ line or hypothalamus-specific deletion of Y2 receptors in mice results in a doubling of trabecular bone volume. However, the specific mechanism by which deletion of Y2 receptors increases bone mass has not yet been identified. Here we show that cultured adherent bone marrow stromal cells from Y2(-/-) mice also demonstrate increased mineralization in vitro. Isolation of two populations of progenitor cell types, an immature mesenchymal stem cell population and a more highly differentiated population of progenitor cells, revealed a greater number of the progenitor cells within the bone of Y2(-/-) mice. Analysis of Y receptor transcripts in cultured stromal cells from wild-type mice revealed high levels of Y1 but not Y2, Y4, Y5, or y6 receptor mRNA. Interestingly, germ line Y2 receptor deletion causes Y1 receptor down-regulation in stromal cells and bone tissue possibly due to the lack of feedback inhibition of NPY release and subsequent overstimulation of Y1 receptors. Furthermore, deletion of Y1 receptors resulted in increased bone mineral density in mice. Together, these findings indicate that the greater number of mesenchymal progenitors and the altered Y1 receptor expression within bone cells in the absence of Y2 receptors are a likely mechanism for the greater bone mineralization in vivo and in vitro, opening up potential new treatment avenues for osteoporosis.

  • 32.
    Lundberg, Pernilla
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Koskinen, Cecilia
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Baldock, Paul A
    Löthgren, Hanna
    Stenberg, Åsa
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Lerner, Ulf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Oldenborg, Per-Arne
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Histologi med cellbiologi.
    Osteoclast formation is strongly reduced both in vivo and in vitro in the absence of CD47/SIRPalpha-interaction2007Inngår i: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 352, nr 2, 444-448 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Physical interaction between the cell surface receptors CD47 and signal regulatory protein alpha (SIRPalpha) was reported to regulate cell migration, phagocytosis, cytokine production, and macrophage fusion. However, it is unclear if the CD47/SIRPalpha-interaction can also regulate macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor (NF)-kappaB ligand (RANKL)-stimulated formation of osteoclasts. Here, we show that functional blocking antibodies to either CD47 or SIRPalpha strongly reduced formation of multinucleated tartrate-resistant acid phosphatase (TRAP)+ osteoclasts in cultures of murine hematopoietic cells, stimulated in vitro by M-CSF and RANKL. In addition, the numbers of osteoclasts formed in M-CSF/RANKL-stimulated bone marrow macrophage cultures from CD47-/- mice were strongly reduced, and bones of CD47-/- mice exhibited significantly reduced osteoclast numbers, as compared with wild-type controls. We conclude that the CD47/SIRPalpha interaction is important for M-CSF/RANKL-stimulated osteoclast formation both in vivo and in vitro, and that absence of CD47 results in decreased numbers of osteoclasts in CD47-/- mice.

  • 33.
    Lundberg, Pernilla
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Morhed-Hultvall, ML
    Twetman, Svante
    Mutans streptococci colonization and longitudinal caries detection with laser fluorescence in fissures of newly erupted 1st permanent molars.2007Inngår i: Acta Odontologica Scandinavica, ISSN 0001-6357, Vol. 65, nr 4, 189-193 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE: To longitudinally apply a laser fluorescence (LF) device (DIAGNOdent) in newly erupted 1st permanent molars over a 3-year period and to relate the findings to mutans streptococci (MS) colonization, fissure morphology, and caries development. MATERIAL AND METHODS: The material consisted of 101 consecutive 5 to 6-year-old children attending a Public Dental Clinic and who volunteered after ethical approval and informed consent had been given. Only fully erupted molars with clinically sound fissures were included. At baseline, the fissures were subjectively categorized as "shallow" or "deep", and, prior to the LF readings, a plaque sample was collected and cultivated for MS using a chair-side kit. The registrations were repeated annually and the microbial samplings after 2 years. The total drop-out rate was 12%. RESULTS: The mean LF values increased significantly (p<0.05) with increasing age from 8.2 to 12.4 in the teeth that remained sound. Thirty-five teeth were decayed or filled during the follow-up and their mean LF values increased from 13.4 to 40.7. The LF readings were significantly higher in molars with "deep" fissures (p<0.05) at all visits. MS colonization at baseline was associated with an increased risk for caries (OR = 11.6, p<0.05) and significantly elevated LF readings. Baseline LF readings > or =12 were not diagnostic for dentin caries or fillings over the study period (sensitivity 0.57; specificity 0.86). CONCLUSION: LF readings could be used to some extent to monitor fissure morphology and caries development in fissures of newly permanent molars over time, but elevated initial values were not predictive for caries development.

  • 34.
    Matemba, Stephen
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Lie, Anita
    Umeå universitet, Medicinsk fakultet, Odontologi.
    Ransjö, Maria
    Umeå universitet, Medicinsk fakultet, Odontologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Regulation of osteoclastogenesis by gap junction communication2006Inngår i: Journal of cellular biochemistry, Vol. 99, nr 2, 528-37 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Receptor activator of NF-kappaB ligand (RANKL) is crucial in osteoclastogenesis but signaling events involved in osteoclast differentiation are far from complete and other signals may play a role in osteoclastogenesis. A more direct pathway for cellular crosstalk is provided by gap junction intercellular channel, which allows adjacent cells to exchange second messengers, ions, and cellular metabolites. Here we have investigated the role of gap junction communication in osteoclastogenesis in mouse bone marrow cultures. Immunoreactive sites for the gap junction protein connexin 43 (Cx43) were detected in the marrow stromal cells and in mature osteoclasts. Carbenoxolone (CBX) functionally blocked gap junction communication as demonstrated by a scrape loading Lucifer Yellow dye transfer technique. CBX caused a dose-dependent inhibition (significant > or = 90 microM) of the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells formed in 7- to 8-day marrow cultures stimulated by parathyroid hormone (PTH; 10 nM) or forskolin (FSK; 1 microM). Furthermore, CBX (100 microM) significantly inhibited prostaglandin E2 (PGE2; 10 microM) and 1,25(OH)2-vitamin D3 stimulated osteoclast differentiation in the mouse bone marrow cultures. Consequently, quantitative real-time polymerase chain reaction (PCR) analysis demonstrated that CBX downregulated the expression of osteoclast phenotypic markers, but without having any significant effects on RANK, RANKL, and osteoprotegerin (OPG) mRNA expression. However, the results demonstrated that CBX significantly inhibits RANKL-stimulated (100 ng/ml) osteoclastogenesis in the mouse bone marrow cultures. Taken together, our results suggests that gap junctional diffusion of messenger molecules interacts with signaling pathways downstream RANKL in osteoclast differentiation. Further studies are required to define the precise mechanisms and molecular targets involved. Copyright 2006 Wiley-Liss, Inc.

  • 35.
    Nordstrand, Annika
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Nilsson, Jonas
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Tieva, Åse
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Wikström, Pernilla
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Lerner, Ulf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Widmark, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Establishment and validation of an in vitro co-culture model to study the interactions between bone and prostate cancer cells2009Inngår i: Clinical & experimental metastasis, ISSN 0262-0898, Vol. 26, nr 8, 945-953 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bone is the preferred site for prostate cancer (PCa) metastases. Once the tumor has established itself within the bone there is virtually no cure. To better understand the interactions between the PCa cells and bone environment in the metastatic process new model systems are needed. We have established a two-compartment in vitro co-culturing model that can be used to follow the trans-activation of bone and/or tumor cells. The model was validated using two PCa tumor cell lines (PC-3; lytic and LNCaP; mixed/osteoblastic) and one osteolytic inducing factor, 1,25-dihydroxyvitamin D(3) (D3). Results were in accordance with the expected bone phenotypes; PC-3 cells and D3 gave osteolytic gene expression profiles in calvariae, with up-regulation of genes needed for osteoclast differentiation, activation and function; Rankl, CathK, Trap and MMP-9, and down-regulation of genes associated with osteoblast differentiation and bone mineralization; Alp, Ocl and Dkk-1. LNCaP cells activated genes in the calvarial bones associated with osteoblast differentiation and mineralization, with marginal effects on osteolytic genes. The results were strengthened by similar changes in protein expression for a selection of the analyzed genes. Furthermore, the osteolytic gene expression profiles in calvarial bones co-cultured with PC-3 cells or with D3 were correlated with the actual ongoing resorptive process, as assessed by the release of collagen fragments from the calvariae. Our results show that the model can be used to follow tumor-induced bone remodeling, and by measuring changes in gene expression in the tumor cells we can also study how they respond to the bone microenvironment.

  • 36.
    Nordström, Anna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin.
    Gerdhem, Paul
    Department of Orthopaedics, Malmö University Hospital, Sweden.
    Brändström, Helena
    Department of Medical Sciences, Uppsala University, Sweden .
    Stiger, Fredrik
    Department of Medical Sciences, Uppsala University, Sweden .
    Lerner, Ulf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Lorentzon, Mattias
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin.
    Obrant, Karl
    Department of Orthopaedics, Malmö University Hospital, Sweden.
    Nordström, Peter
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Geriatrik. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Idrottsmedicin.
    Åkesson, Kristina
    Department of Orthopaedics, Malmö University Hospital, Sweden.
    Interleukin-6 promoter polymorphism is associated with bone quality assessed by calcaneus ultrasound and previous fractures in a cohort of 75-year-old women2004Inngår i: Osteoporosis International, ISSN 0937-941X, E-ISSN 1433-2965, ISSN 0937-941X, Vol. 15, nr 10, 820-826 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Interleukin 6 (IL-6) is a multifunctional cytokine and a potent stimulator of bone resorption and has been implicated in the pathogenesis of osteoporosis in postmenopausal women. The aim of this study was to investigate if a functional IL-6 promoter polymorphism (-174) was related to bone mass and fractures in a cohort consisting of 964 postmenopausal Caucasian women aged 75 years. Bone mineral density (BMD; g/cm2) of the femoral neck, lumbar spine and total body was measured using dual energy X-ray absorptiometry (DXA). Quantitative ultrasound (QUS) was also measured in the calcaneus and quantified as speed of sound (SOS; m/s), broadband ultrasound attenuation (BUA; dB/MHz), and stiffness index (SI). IL-6 genotypes was determined by restriction fragment length polymorphism (RFLP) using the restriction enzyme NlaIII. The frequencies of the different IL-6 genotypes were 27.5% (GG), 47.9% (GC), 24.6% (CC). The IL-6 polymorphism (presence of G) was independently related to a lower stiffness (beta=-0.07; P=0.03) and BUA (beta=-0.08; P=0.02), but not to BMD at any site measured by DXA. In the cohort, 420 subjects (44%) reported at least one fracture during their lifetime, and 349 (36%) reported at least one fracture after the age of 50. Using binary logistic regression, the IL-6 polymorphism (presence of G) was significantly related to an increased risk of a previous fracture during life (odds ratio 1.46, 95% CI 1.08-1.97) and to an increased risk of a fracture occurring after 50 years of age (odds ratio 1.37, 95% CI 1.004-1.88). The risk was further increased for fractures grouped as osteoporotic fractures (odds ratio 1.67, 95% CI 1.14-2.45), including forearm fractures (odds ratio 1.59, 95% CI 1.05-2.40). In conclusion, presence of G allele in the IL-6 promoter polymorphism at position -174 is independently related to previous fractures in postmenopausal women. This association may be related primarily to an altered bone quality identified by QUS and not a lower bone mass. This is also the first demonstration of association of IL-6 gene polymorphism to calcaneal QUS.

  • 37.
    Palmqvist, Py
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Lundberg, Pernilla
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Lundgren, Inger
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Hänström, Lennart
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    IL-1beta and TNF-alpha regulate IL-6-type cytokines in gingival fibroblasts.2008Inngår i: Journal of Dental Research, ISSN 0022-0345, Vol. 87, nr 6, 558-563 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Interleukin-6 (IL-6)-type cytokines are pleiotropic molecules capable of stimulating bone resorption and expressed by numerous cell types. In the present study, we tested the hypothesis that gingival fibroblasts may exert local osteotropic effects through production of IL-6 and related cytokines. IL-6-type cytokine expression and regulation by IL-1beta and tumor necrosis factor-alpha (TNF-alpha) were studied in fibroblasts from the non-inflamed gingiva of healthy individuals. Constitutive mRNA expression of IL-6, IL-11, and leukemia inhibitory factor (LIF), but not of oncostatin M (OSM), was demonstrated, as was concentration-dependent stimulation of IL-6 and LIF mRNA and of protein by IL-1beta and TNF-alpha. IL-11 mRNA and protein were concentration-dependently stimulated by IL-1beta. The signaling pathway involved in IL-6 and LIF mRNA stimulation involved MAP kinases, but not NF-kappaB. The findings support the view that resident cells may influence the pathogenesis of periodontal disease through osteotropic IL-6-type cytokine production mediated by activation of MAP kinases. Abbreviations: IL-1alpha (interleukin-1alpha); IL-1beta (interleukin-1beta); IL-6 (interleukin-6); IL-11 (interleukin-11); LIF (leukemia inhibitory factor); OSM (oncostatin M); alpha(1)-coll. I (alpha(1)-collagen I); ALP (alkaline phosphatase); BMP-2 (bone morphogenetic protein-2); OC (osteocalcin); BSP (bone sialoprotein); TNFR I (tumor necrosis factor receptor I); TNFR II (tumor necrosis factor receptor II); IL-1R1 (interleukin-1 receptor 1); GAPDH (glyceraldehyde-3-phosphate dehydrogenase); RPL13A (ribosomal protein L13A); mRNA (messenger ribonucleic acid); cDNA (complementary deoxyribonucleic acid); PCR (polymerase chain-reaction); BCA (bicinchoninic acid); ELISA (enzyme-linked immunosorbent assay); alpha-MEM (alpha modification of Minimum Essential Medium); and FCS (fetal calf serum).

  • 38.
    Palmqvist, Py
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Kariologi.
    Lundberg, Pernilla
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Persson, Emma
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Lundgren, Inger
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Lie, Anita
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Conaway, HH
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Inhibition of hormone and cytokine-stimulated osteoclastogenesis and bone resorption by interleukin-4 and interleukin-13 is associated with increased osteoprotegerin and decreased RANKL and RANK in a STAT6-dependent pathway2006Inngår i: Journal of Biological Chemistry, ISSN 0021-9258, Vol. 281, nr 5, 2414-2429 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Interleukin (IL)-4 and IL-13 are cytokines that inhibit bone resorption. Data showing an inhibitory effect of IL-4 and IL-13 on RANK mRNA in mouse calvariae were first reported at the 22nd American Society for Bone and Mineral Research Meeting (Lerner, U.H., and Conaway, H. H. 2000) J. Bone Min. Res. 15, Suppl. 1, Abstr. SU 230). In the present study, release of 45Ca from cultured mouse calvarial bones stimulated by different cytokines, peptides, and steroid hormones was inhibited by IL-4 and IL-13. IL-4 and IL-13 decreased receptor activator of nuclear factor-kappaB ligand (RANKL) and RANK mRNA and increased osteoprotegerin (OPG) mRNA in calvariae. Additionally, the cytokines decreased RANKL protein and increased OPG protein in calvarial bones. In osteoblasts isolated from calvariae, both an increase in RANKL mRNA and a decrease in OPG mRNA and protein elicited by vitamin D3 were reversed by IL-4 and IL-13. IL-4 and IL-13 decreased the number of tartrate-resistant acid phosphatase positive multinucleated cells and the mRNA expression of calcitonin receptor, tartrate-resistant acid phosphatase, and cathepsin K in mouse spleen cells and bone marrow macrophages (BMM) treated with macrophage colony-stimulating factor and RANKL. Inhibition of mRNA for RANK and the transcription factor NFAT2 was also noted in spleen cell and BMM cultures treated with IL-4 and IL-13. In addition, RANK mRNA and RANK protein were decreased by IL-4 and IL-13 in RAW 264.7 cells. Osteoblasts, spleen cells, and BMM expressed mRNA for the four proteins making up the IL-4 and IL-13 receptors. No effects by IL-4 on bone resorption and osteoclast formation or on RANKL and RANK mRNA expression were seen in Stat6-/- mice. The data indicate that IL-4 and IL-13, via a STAT6-dependent pathway, inhibit osteoclast differentiation and bone resorption by activating receptors on osteoblasts and osteoclasts that affect the RANKL/RANK/OPG system.

  • 39.
    Palmqvist, Py
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Persson, Emma
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Conaway, HH
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    IL-6, leukemia inhibitory factor, and oncostatin M stimulate bone resorption and regulate the expression of receptor activator of NF-kB ligand, osteoprotegerin, and receptor activator of NF-kB in mouse calvariae2002Inngår i: Journal of Immunology, ISSN 0022-1767, Vol. 169, nr 6, 3353-3362 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    IL-6, leukemia inhibitory factor (LIF), and oncostatin M (OSM) are IL-6-type cytokines that stimulate osteoclast formation and function. In the present study, the resorptive effects of these agents and their regulation of receptor activator of NF-kappaB ligand (RANKL), RANK, and osteoprotegerin (OPG) were studied in neonatal mouse calvaria. When tested separately, neither human (h) IL-6 nor the human soluble IL-6R (shIL-6R) stimulated bone resorption, but when hIL-6 and the shIL-6R were combined, significant stimulation of both mineral and matrix release from bone explants was noted. Semiquantitative RT-PCR showed that hIL-6 plus shIL-6R enhanced the expression of RANKL and OPG in calvarial bones, but decreased RANK expression. Human LIF, hOSM, and mouse OSM (mOSM) also stimulated 45Ca release and enhanced the mRNA expression of RANKL and OPG in mouse calvaria, but had no effect on the expression of RANK. In agreement with the RT-PCR analyses, ELISA measurements showed that both hIL-6 plus shIL-6R and mOSM increased RANKL and OPG proteins. 1,25-Dihydroxyvitamin D3 (D3) also increased the RANKL protein level, but decreased the protein level of OPG. OPG inhibited 45Ca release stimulated by RANKL, hIL-6 plus shIL-6R, hLIF, hOSM, mOSM, and D3. An Ab neutralizing mouse gp130 inhibited 45Ca release induced by hIL-6 plus shIL-6R. These experiments demonstrated stimulation of calvarial bone resorption and regulation of mRNA and protein expression of RANKL and OPG by D3 and IL-6 family cytokines as well as regulation of RANK expression in preosteoclasts/osteoclasts of mouse calvaria by D3 and hIL-6 plus shIL-6R.

  • 40.
    Persson, Emma
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    The neuropeptide VIP and the IL-6 family of cytokines in bone: effects on bone resorption, cytokine expression and receptor signalling in osteoblasts and bone marrow stromal cells2005Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Bone tissue is continuously degraded and rebuilt to respond to the needs of the body. Cells of the osteoblast lineage are responsible for the formation of bone, whereas the resorption of bone tissue is carried out by osteoclasts. To prevent imbalance between bone formation and resorption, these processes are delicately regulated by a complex network of both systemic factors and factors produced locally in the bone microenvironment, including members of the IL-6 family of cytokines. During the last decades, the presence of nerve fibers in skeletal tissue and presence of receptors for several neurotransmitters on both osteoblasts and osteoclasts, have suggested a possible role for neuropeptides in the regulation of skeletal metabolism.

    The overall aim of this study was to investigate the roles of cytokines in the IL-6 family and the neuropeptide VIP in regulation of osteotropic cytokine expression and bone metabolism in vitro.

    In Paper I, stimulation of bone resorption by the cytokine IL-6, in the presence of its soluble receptor sIL-6R, was demonstrated in mouse calvarial bones. OSM and LIF, other members of the IL-6 family of cytokines, were also shown to increase bone resorption. Furthermore, IL-6+sIL-6R, LIF, and OSM increased the expression of RANKL, which by binding to its receptor RANK functions as a crucial inducer of osteoclast formation and activation.

    In Paper II-IV, the effects of the neuropeptide VIP and related peptides on expression of osteotropic cytokines by osteoblasts and bone resorption in vitro have been studied. VIP and PACAP-38 both increased IL-6 production in osteoblasts in a time- and concentration-dependent manner. In contrast, no effect was seen with the related peptide secretin, indicating that the effects were mediated by the VPAC2 receptor. VIP and PACAP, in contrast to secretin, also induced IL-6 promoter activity in osteoblastic MC3T3-E1 cells transfected with an IL-6 promoter/luciferase construct. The effects of VIP on IL-6 were shown to be mediated by several intracellular pathways, including cAMP/PKA/CREB, AP-1, and C/EBP, but not NF-kB or the cAMP-activated Epac pathway. The release of IL-6 from osteoblasts was increased by several pro-inflammatory osteotropic cytokines, including interleukin-1b, an effect that was further potentiated by VIP, indicating a possible neuro-immunomodulatory interaction in the regulation of bone metabolism. VIP and PACAP-38 also increased the osteoblastic expression of RANKL and decreased the expression of OPG and M-CSF, factors crucial in regulation of differentiation and activation of osteoclasts. Although this indicated a possible bone resorptive effect, VIP was found to decrease osteoclast formation and bone resorption by directly targeting osteoclast progenitor cells through an inhibitory mechanism.

    In conclusion, the results in this thesis indicate that several cytokines in the IL-6 family stimulate bone resorption in calvarial bones in vitro, most likely through the RANKL-RANK interaction. Furthermore, expression of the osteotropic cytokine IL-6 in osteoblasts is stimulated by the neuropeptide VIP through VPAC2 receptors via several intracellular pathways, further strengthening the role of neuropeptides as local regulators of bone metabolism.

  • 41.
    Persson, Emma
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    The neuropeptide VIP potentiates IL-6 production induced by proinflammatory osteotropic cytokines in calvarial osteoblasts and the osteoblastic cell line MC3T3-E1.2005Inngår i: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, Vol. 335, nr 3, 705-711 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Skeletal turnover is orchestrated by a complex network of regulatory factors. Lately, regulation of bone metabolism through neuro-osteological interactions has been proposed. Here, we address the question whether IL-6 production can be affected by interactions between the neuropeptide VIP and proinflammatory, bone-resorbing cytokines. By using calvarial osteoblasts, we showed that IL-1beta increased IL-6 production time- and concentration-dependently, and that these effects were potentiated by VIP. Furthermore, IL-1beta stimulated IL-6 promoter activity in the osteoblastic cell line MC3T3-E1 stably transfected with a human IL-6 promoter/luciferase construct, and both VIP, and the related neuropeptide PACAP-38, increased the effect of IL-1beta in a synergistic manner. The IL-6 protein release from calvarial osteoblasts was also stimulated by the osteoclastogenic, proinflammatory cytokines IL-11, LIF, OSM, IL-17, TGF-beta, and TNF-alpha. All effects, except for that of TNF-alpha, were synergistically potentiated by VIP. These findings further support the role of neuropeptides, and the presence of neuro-immunological interactions, in bone metabolism.

  • 42.
    Persson, Emma
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Voznesensky, OS
    Huang, YF
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Increased expression of interleukin-6 by vasoactive intestinal peptide is associated with regulation of CREB, AP-1 and C/EBP, but not NF-kappaB, in mouse calvarial osteoblasts.2005Inngår i: Bone, ISSN 8756-3282, Vol. 37, nr 4, 513-529 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Interleukin-6 (IL-6), and the related cytokines IL-11, leukemia inhibitory factor (LIF) and oncostatin M (OSM), are potent stimulators of osteoclastic bone resorption. In the present study, we have addressed the possibility that the neuropeptide vasoactive intestinal peptide (VIP) may regulate the production of and/or sensitivity to the IL-6 family of cytokines in mouse calvarial osteoblasts. VIP stimulated IL-6 mRNA expression and protein release in a time- and concentration-dependent manner, whereas mRNA expression of the IL-6 receptor, as well as mRNA expressions of IL-11, LIF, OSM and their cognate receptors, were unaffected by VIP. In cells transfected with the IL-6 promoter coupled to luciferase, VIP increased transcriptional activity. The effects of VIP were shared by the related neuropeptide PACAP-38, belonging to the same superfamily of neuropeptides, whereas secretin did not have any effect, indicating that the effects were mediated by VPAC2 receptors. The effects of VIP were potentiated by the cyclic AMP phosphodiesterase inhibitor rolipram and mimicked by forskolin, indicating the involvement of the cyclic AMP/protein kinase A pathway. This was further demonstrated by the facts that the stimulatory effect of VIP on luciferase activity could be reversed by the PKA inhibitors H-89 and KT5720 and was mimicked by cyclic AMP analogues selective for PKA, but not by those selective for Epac. In addition, VIP enhanced the phosphorylation of CREB, as assessed by both immunocytochemical analysis and Western blot. The DNA binding activity of nuclear extracts to C/EBP was increased by VIP, whereas binding to AP-1 was decreased. In contrast, DNA binding to NF-kappaB, as well as nuclear translocation of NF-kappaB and C/EBP, were unaffected by VIP. The mRNA expressions of C/EBPbeta, C/EBPdelta, C/EBPgamma, c-Jun, JunB, c-Fos, Fra-1 and IkappaBalpha and protein level of IkappaBalpha were all unaffected by VIP. These observations, together, demonstrate that VIP stimulates IL-6 production in osteoblasts by a mechanism likely to be mediated by VPAC2 receptors and dependent on cyclic AMP/protein kinase A/CREB activation and also involving the transcription factors C/EBP and AP-1.

  • 43.
    Ransjö, Maria
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Lundgren, Stefan
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Käkkirurgi.
    Det växer fast - om implantat och benbildning.: På bettet hela livet, om  odontologisk vetenskap i Umeå. pp2006Inngår i: På bettet hela livet, om  odontologisk vetenskap i Umeå.: En bok från Forskningens dag 2006, Medicinska fakulteten, Umeå universitet. Författare Svante Twetman / [ed] Medicinska fakulteten vid Umeå universitet, Umeå: Umeå universitet , 2006, 67-82 s.Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 44.
    Ransjö, Maria
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Sahli, J
    Lie, Anita
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Expression of connexin 43 mRNA in microisolated murine osteoclasts and regulation of bone resorption in vitro by gap junction inhibitors.2003Inngår i: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, Vol. 18;303, nr 4, 1179-1185 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Several studies have demonstrated that connexin 43 (Cx43) mediates signals important for osteoblast function and osteogenesis. The role of gap junctional communication in bone resorption is less clear. We have investigated the expression of Cx43 mRNA in osteoclasts and bone resorption cultures and furthermore, the functional importance of gap junctional communication in bone resorption. RT-PCR analysis demonstrated Cx43 mRNA expression in mouse bone marrow cultures and in osteoclasts microisolated from the marrow cultures. Cx43 mRNA was also expressed in bone resorption cultures with osteoclasts and osteoblasts/stromal cells incubated for 48h on devitalized bone slices. An up-regulation of Cx43 mRNA was detected in parathyroid (PTH)-stimulated (0.1 nM) bone resorption. Two inhibitors of gap junction communication, 18alpha-glycyrrhetinic acid (30 microM) and oleamide (100 microM), significantly inhibited PTH- and 1,25-(OH)(2)D(3)-stimulated osteoclastic pit formation. In conclusion, our data indicate a functional role for gap junction communication in bone resorption.

  • 45. Rauch, Alexander
    et al.
    Seitz, Sebastian
    Baschant, Ulrike
    Schilling, Arndt F
    Illing, Anett
    Stride, Brenda
    Kirilov, Milen
    Mandic, Vice
    Takacz, Andrea
    Schmidt-Ullrich, Ruth
    Ostermay, Susanne
    Schinke, Thorsten
    Spanbroek, Rainer
    Zaiss, Mario M
    Angel, Peter E
    Lerner, Ulf H
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    David, Jean-Pierre
    Reichardt, Holger M
    Amling, Michael
    Schütz, Günther
    Tuckermann, Jan P
    Glucocorticoids suppress bone formation by attenuating osteoblast differentiation via the monomeric glucocorticoid receptor2010Inngår i: Cell Metabolism, ISSN 1550-4131, Vol. 11, nr 6, 517-531 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Development of osteoporosis severely complicates long-term glucocorticoid (GC) therapy. Using a Cre-transgenic mouse line, we now demonstrate that GCs are unable to repress bone formation in the absence of glucocorticoid receptor (GR) expression in osteoblasts as they become refractory to hormone-induced apoptosis, inhibition of proliferation, and differentiation. In contrast, GC treatment still reduces bone formation in mice carrying a mutation that only disrupts GR dimerization, resulting in bone loss in vivo, enhanced apoptosis, and suppressed differentiation in vitro. The inhibitory GC effects on osteoblasts can be explained by a mechanism involving suppression of cytokines, such as interleukin 11, via interaction of the monomeric GR with AP-1, but not NF-kappaB. Thus, GCs inhibit cytokines independent of GR dimerization and thereby attenuate osteoblast differentiation, which accounts, in part, for bone loss during GC therapy.

  • 46.
    Sahlin-Platt, Annika
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Örtengren, Ulf
    Mladenovic, Zivko
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Ransjö, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Effects of Dyract AP and released ionic products on periodontal ligament cells and bone marrow cultures2008Inngår i: Dental Materials, ISSN 0109-5641, E-ISSN 1879-0097, Vol. 24, nr 12, 1623-1630 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVES: The aim of this work was to investigate the release of inorganic ionic products from specimens of the polyacid-modified composite resin Dyract AP (DAP) and furthermore, to analyze the biological effect of DAP and the medium extract in human periodontal ligament (PDL) cells and mouse bone marrow cell (BMC) cultures.

    METHODS: Ion release from DAP specimens immersed in cell culture medium was analyzed with inductively coupled plasma optical emission spectroscopy (ICP-OES). Cells were cultured with either DAP specimens or with DAP media extract and effects on cell proliferation, osteoblastic gene expression and mineralization capacity were analyzed with direct-contact tests, neutral red (NR) uptake, quantitative real-time PCR and a bone nodule formation assay.

    RESULTS: ICP-OES analysis of DAP extract demonstrated a significant increase in fluoride, strontium and silica. PDL cells demonstrated normal growth pattern in the direct-contact tests with the material. DAP extracts produced a dose-dependent stimulation of cell proliferation and concomitant inhibition of osteoblast specific markers and nodule formation.

    SIGNIFICANCE: The compomer may have possible bioactive properties due to ions leaching out from the filler component.

  • 47. Schwab, AM
    et al.
    Granholm, S
    Persson, Emma
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Wilkes, B
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Stimulation of resorption in cultured mouse calvarial bones by thiazolidinediones.2005Inngår i: Endocrinology, ISSN 0013-7227, Vol. 146, nr 10, 4349-4361 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dosage-dependent release of 45Ca was observed from prelabeled mouse calvarial bones after treatment with two thiazolidinediones, troglitazone and ciglitazone. Release of 45Ca by ciglitazone was decreased by the osteoclast inhibitors acetazolamide, calcitonin, 3-amino-1-hydroxypropylidene-1,1-bisphosphonate, and IL-4, but not affected by the peroxisome proliferator-activated receptor gamma antagonist, GW 9662, the mitotic inhibitor, hydroxyurea, or indomethacin. Enhanced expression of receptor activator of nuclear factor-kappaB ligand (RANKL) mRNA and protein and decreased osteoprotegerin (OPG) mRNA and protein were noted after ciglitazone treatment of calvariae. Ciglitazone and RANKL each caused increased mRNA expression of osteoclast markers: calcitonin receptor, tartrate-resistant acid phosphatase, cathepsin K, matrix metalloproteinase-9, integrin beta3, and nuclear factor of activated T cells 2. OPG inhibited mRNA expression of RANKL stimulated by ciglitazone, mRNA expression of osteoclast markers stimulated by ciglitazone and RANKL, and 45Ca release stimulated by troglitazone and ciglitazone. Increased expression of IL-1alpha mRNA by ciglitazone was not linked to resorption stimulated by the thiazolidinedione. Ciglitazone did not increase adipogenic gene expression but enhanced osteocalcin mRNA in calvariae. In addition to exhibiting sensitivity to OPG, data indicate that stimulation of osteoclast differentiation and activity by thiazolidinediones may occur by a nonperoxisome proliferator-activated receptor gamma-dependent pathway that does not require cell proliferation, prostaglandins, or IL-1alpha but is characterized by an increased RANKL to OPG ratio.

  • 48. Smith, R
    et al.
    Ransjö, Maria
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Tatarczuch, L
    Song, SJ
    Pagel, C
    Morrison, JR
    Pike, RN
    Mackie, EJ
    Activation of protease-activated receptor-2 leads to inhibition of osteoclast differentiation.2004Inngår i: Journal of Bone and Mineral Research, ISSN 0884-0431, Vol. 19, nr 3, 507-516 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    PAR-2 is expressed by osteoblasts and activated by proteases present during inflammation. PAR-2 activation inhibited osteoclast differentiation induced by hormones and cytokines in mouse bone marrow cultures and may protect bone from uncontrolled resorption. INTRODUCTION: Protease-activated receptor-2 (PAR-2), which is expressed by osteoblasts, is activated specifically by a small number of proteases, including mast cell tryptase and factor Xa. PAR-2 is also activated by a peptide (RAP) that corresponds to the "tethered ligand" created by cleavage of the receptor's extracellular domain. The effect of activating PAR-2 on osteoclast differentiation was investigated. MATERIALS AND METHODS: Mouse bone marrow cultures have been used to investigate the effect of PAR-2 activation on osteoclast differentiation induced by parathyroid hormone (PTH), 1,25 dihydroxyvitamin D3 [1,25(OH)2D3], and interleukin-11 (IL-11). Expression of PAR-2 by mouse bone marrow, mouse bone marrow stromal cell-enriched cultures, and the RAW264.7 osteoclastogenic cell line was demonstrated by RT-PCR. RESULTS: RAP was shown to inhibit osteoclast differentiation induced by PTH, 1,25(OH)2D3, or IL-11. Semiquantitative RT-PCR was used to investigate expression of mediators of osteoclast differentiation induced by PTH, 1,25(OH)2D3, or IL-11 in mouse bone marrow cultures and primary calvarial osteoblast cultures treated simultaneously with RAP. In bone marrow and osteoblast cultures treated with PTH, 1,25(OH)2D3, or IL-11, RAP inhibited expression of RANKL and significantly suppressed the ratio of RANKL:osteoprotegerin expression. Activation of PAR-2 led to reduced expression of prostaglandin G/H synthase-2 in bone marrow cultures treated with PTH, 1,25(OH)2D3, or IL-11. RAP inhibited PTH- or 1,25(OH)2D3-induced expression of IL-6 in bone marrow cultures. RAP had no effect on osteoclast differentiation in RANKL-treated RAW264.7 cells. CONCLUSION: These observations indicate that PAR-2 activation inhibits osteoclast differentiation by acting on cells of the osteoblast lineage to modulate multiple mediators of the effects of PTH, 1,25(OH)2D3, and IL-11. Therefore, the role of PAR-2 in bone may be to protect it from uncontrolled resorption by limiting levels of osteoclast differentiation.

  • 49.
    Souza, PPC
    et al.
    University of Sao Paulo.
    Palmqvist, Py
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Lundgren, Inger
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Lie, Anita
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Costa-Neto, CM
    Lundberg, Pernilla
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Lerner, Ulf H
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Stimulation of IL-6 cytokines in fibroblasts by toll-like receptors 22010Inngår i: Journal of Dental Research, ISSN 0022-0345, E-ISSN 1544-0591, Vol. 89, nr 8, 802-807 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The osteotropic interleukin-6 (IL-6) types of cytokines IL-6, IL-11, and leukemia inhibitory factor (LIF), but not oncostatin M, are expressed by human gingival fibroblasts, and their expressions are regulated by IL-1 and tumor necrosis factor-alpha (TNF-alpha). In the present study, we investigated whether signaling through Toll-like receptor 2 (TLR2) can affect the expression of these cytokines in human gingival fibroblasts. Lipopolysac-charide (LPS) from P. gingivalis was found to stimulate IL-6 and LIF mRNA and protein, but not IL-11 or OSM mRNA. Using two synthetic ligands acting specifically at TLR2 and siRNA knockdown of TLR2, we demonstrated the important role of TLR2 in the stimulation of IL-6 and LIF in gingival fibroblasts. Analysis of these data suggests that signaling through the innate immune system controls the expression of osteotropic cytokines in human gingival fibroblasts.

  • 50. Svensson, Anna C
    et al.
    Johansson, Mattias
    Persson, Emma
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Carchenilla, Marta San Celestino
    Jacobsson, Stig O P
    Umeå universitet, Medicinsk fakultet, Farmakologi och klinisk neurovetenskap, Farmakologi.
    Expression of functional CB1 cannabinoid receptors in retinoic acid-differentiated P19 embryonal carcinoma cells.2006Inngår i: J Neurosci Res, ISSN 0360-4012, Vol. 83, nr 6, 1128-40 s.Artikkel i tidsskrift (Fagfellevurdert)
12 1 - 50 of 54
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf