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Ihalin, R., Eneslatt, K. & Asikainen, S. (2018). Peptidoglycan-associated lipoprotein of Aggregatibacter actinomycetemcomitans induces apoptosis and production of proinflammatory cytokines via TLR2 in murine macrophages RAW 264.7 in vitro. Journal of Oral Microbiology, 10, Article ID 1442079.
Öppna denna publikation i ny flik eller fönster >>Peptidoglycan-associated lipoprotein of Aggregatibacter actinomycetemcomitans induces apoptosis and production of proinflammatory cytokines via TLR2 in murine macrophages RAW 264.7 in vitro
2018 (Engelska)Ingår i: Journal of Oral Microbiology, ISSN 2000-2297, E-ISSN 2000-2297, Vol. 10, artikel-id 1442079Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Peptidoglycan-associated lipoprotein (PAL) is a conserved pro-inflammatory outer membrane lipoprotein in Gram-negative bacteria. Compared to systemic pathogens, little is known about the virulence properties of PAL in Aggregatibacter actinomycetemcomitans (AaPAL). The aims of this study were to investigate the cytolethality of AaPAL and its ability to induce pro-inflammatory cytokine production in macrophages. Mouse macrophages were stimulated with AaPAL, and the production of IL-1β, IL-6, TNF-α, and MCP-1 was measured after 6, 24, and 48 h. To investigate which receptor AaPAL employs for its interaction with macrophages, anti-toll-like receptor (TLR)2 and anti-TLR4 antibodies were used to block respective TLRs on macrophages. Metabolic activity and apoptosis of the macrophages were investigated after stimulation with AaPAL. AaPAL induced the production of MCP-1, TNF-α, IL-6, and IL-1β from mouse macrophages in order of decreasing abundance. The pre-treatment of macrophages with an anti-TLR2 antibody significantly diminished cytokine production. Under AaPAL stimulation, the metabolic activity of macrophages decreased in a dose-and time-dependent manner. Furthermore, AaPAL induced apoptosis in 56% of macrophages after 48 h of incubation. Our data suggest that AaPAL can kill macrophages by apoptosis. The results also emphasize the role of AaPAL as a potent pro-inflammatory agent in A. actinomycetemcomitans-associated infections.

Ort, förlag, år, upplaga, sidor
Taylor & Francis, 2018
Nyckelord
Aggregatibacter actinomycetemcomitans, apoptosis, mouse macrophages, pro-inflammatory tokines, peptidoglycan-associated lipoprotein
Nationell ämneskategori
Odontologi
Identifikatorer
urn:nbn:se:umu:diva-146213 (URN)10.1080/20002297.2018.1442079 (DOI)000427075600001 ()29686780 (PubMedID)
Tillgänglig från: 2018-05-08 Skapad: 2018-05-08 Senast uppdaterad: 2018-06-09Bibliografiskt granskad
Ihalin, R., Zhong, D., Karched, M., Chen, C. & Asikainen, S. (2018). Phosphorylcholine is located in Aggregatibacter actinomycetemcomitans fimbrial protein Flp 1. Medical Microbiology and Immmunology, 207(5-6), 329-338
Öppna denna publikation i ny flik eller fönster >>Phosphorylcholine is located in Aggregatibacter actinomycetemcomitans fimbrial protein Flp 1
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2018 (Engelska)Ingår i: Medical Microbiology and Immmunology, ISSN 0300-8584, E-ISSN 1432-1831, Vol. 207, nr 5-6, s. 329-338Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Phosphorylcholine (ChoP) is covalently incorporated into bacterial surface structures, contributing to host mimicry and promoting adhesion to surfaces. Our aims were to determine the frequency of ChoP display among Aggregatibacter actinomycetemcomitans strains, to clarify which surface structures bear ChoP, and whether ChoP-positivity relates to serum killing. The tested oral (N=67) and blood isolates (N=27) represented 6 serotypes. Mab TEPC-15 was used for immunoblotting of cell lysates and fractions and for immunofluorescence microscopy of cell surface-bound ChoP. The lysates were denatured with urea for hidden ChoP or treated with proteinase K to test whether it binds to a protein. Three ChoP-positive and two ChoP-negative strains were subjected to serum killing in the presence/absence of CRP and using Ig-depleted serum as complement source. Cell lysates and the first soluble cellular fraction revealed a<10kDa band in immunoblots. Among 94 strains, 27 were ChoP positive. No difference was found in the prevalence of ChoP-positive oral (21/67) and blood (6/27) strains. Immunofluorescence microscopy corresponded to the immunoblot results. Proteinase K abolished ChoP reactivity, whereas urea did not change the negative result. The TEPC-15-reactive protein was undetectable in flp1 mutant strain. The survival rate of serotype-b strains in serum was 100% irrespective of ChoP, but that of serotype-a was higher in ChoP-positive (85%) than ChoP-negative (71%) strains. The results suggest that a third of rough-colony strains harbor ChoP and that ChoP is attached to fimbrial subunit protein Flp1. It further seems that ChoP-positivity does not enhance but may reduce A. actinomycetemcomitans susceptibility to serum killing.

Ort, förlag, år, upplaga, sidor
Springer, 2018
Nyckelord
Aggregatibacter actinomycetemcomitans, Serotypes, Periodontitis, Phosphorylcholine, Fimbriae, Flp1, C-reactive protein, Serum resistance
Nationell ämneskategori
Mikrobiologi
Identifikatorer
urn:nbn:se:umu:diva-153696 (URN)10.1007/s00430-018-0554-1 (DOI)000447969100008 ()30056510 (PubMedID)
Forskningsfinansiär
Västerbottens läns landsting
Tillgänglig från: 2018-12-05 Skapad: 2018-12-05 Senast uppdaterad: 2018-12-05Bibliografiskt granskad
Organisationer
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0003-4118-0370

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