Umeå University's logo

umu.sePublications
Change search
Link to record
Permanent link

Direct link
Publications (10 of 13) Show all publications
Willekens, S. M. A., Morini, F., Mediavilla, T., Nilsson, E., Orädd, G., Hahn, M., . . . Marcellino, D. (2024). An MR-based brain template and atlas for optical projection tomography and light sheet fluorescence microscopy in neuroscience. Frontiers in Neuroscience, 18, Article ID 1328815.
Open this publication in new window or tab >>An MR-based brain template and atlas for optical projection tomography and light sheet fluorescence microscopy in neuroscience
Show others...
2024 (English)In: Frontiers in Neuroscience, ISSN 1662-4548, E-ISSN 1662-453X, Vol. 18, article id 1328815Article in journal (Refereed) Published
Abstract [en]

Introduction: Optical Projection Tomography (OPT) and light sheet fluorescence microscopy (LSFM) are high resolution optical imaging techniques, ideally suited for ex vivo 3D whole mouse brain imaging. Although they exhibit high specificity for their targets, the anatomical detail provided by tissue autofluorescence remains limited.

Methods: T1-weighted images were acquired from 19 BABB or DBE cleared brains to create an MR template using serial longitudinal registration. Afterwards, fluorescent OPT and LSFM images were coregistered/normalized to the MR template to create fusion images.

Results: Volumetric calculations revealed a significant difference between BABB and DBE cleared brains, leading to develop two optimized templates, with associated tissue priors and brain atlas, for BABB (OCUM) and DBE (iOCUM). By creating fusion images, we identified virus infected brain regions, mapped dopamine transporter and translocator protein expression, and traced innervation from the eye along the optic tract to the thalamus and superior colliculus using cholera toxin B. Fusion images allowed for precise anatomical identification of fluorescent signal in the detailed anatomical context provided by MR.

Discussion: The possibility to anatomically map fluorescent signals on magnetic resonance (MR) images, widely used in clinical and preclinical neuroscience, would greatly benefit applications of optical imaging of mouse brain. These specific MR templates for cleared brains enable a broad range of neuroscientific applications integrating 3D optical brain imaging.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2024
Keywords
brain template, LSFM, mesoscopic imaging, MRI, neuroimaging, OPT
National Category
Neurosciences Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:umu:diva-223641 (URN)10.3389/fnins.2024.1328815 (DOI)001198866200001 ()38601090 (PubMedID)2-s2.0-85189910322 (Scopus ID)
Funder
The Kempe FoundationsSwedish Research Council, 2020-06224Swedish Research Council, 2018-05851Swedish Research Council, 2020-02300Novo Nordisk FoundationFamiljen Erling-Perssons Stiftelse
Available from: 2024-04-24 Created: 2024-04-24 Last updated: 2024-04-24Bibliographically approved
Lehrstrand, J., Davies, W. I. L., Hahn, M., Korsgren, O., Alanentalo, T. & Ahlgren, U. (2024). Illuminating the complete ß-cell mass of the human pancreas - signifying a new view on the islets of Langerhans. Nature Communications, 15(1), Article ID 3318.
Open this publication in new window or tab >>Illuminating the complete ß-cell mass of the human pancreas - signifying a new view on the islets of Langerhans
Show others...
2024 (English)In: Nature Communications, E-ISSN 2041-1723, Vol. 15, no 1, article id 3318Article in journal (Refereed) Published
Abstract [en]

Pancreatic islets of Langerhans play a pivotal role in regulating blood glucose homeostasis, but critical information regarding their mass, distribution and composition is lacking within a whole organ context. Here, we apply a 3D imaging pipeline to generate a complete account of the insulin-producing islets throughout the human pancreas at a microscopic resolution and within a maintained spatial 3D context. These data show that human islets are far more heterogenous than previously accounted for with regards to their size distribution and cellular make up. By deep tissue 3D imaging, this in-depth study demonstrates that 50% of the human insulin-expressing islets are virtually devoid of glucagon-producing α-cells, an observation with significant implications for both experimental and clinical research.

Place, publisher, year, edition, pages
Springer Nature, 2024
National Category
Endocrinology and Diabetes Cell and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-223844 (URN)10.1038/s41467-024-47686-7 (DOI)001204844700001 ()38632302 (PubMedID)2-s2.0-85190704494 (Scopus ID)
Funder
The Kempe Foundations, SMK-1455Swedish Research Council, 2017- 01307Swedish Research Council, 2023-02221Swedish Child Diabetes FoundationNovo Nordisk Foundation, NNF21OC0069771Novo Nordisk Foundation, NNF21OC0084520Novo Nordisk Foundation, NNF20OC0063600Insamlingsstiftelsen Diabetes Wellness, PG21-6566Ernfors Foundation, 2023Diabetesfonden, DIA2021-59
Available from: 2024-04-29 Created: 2024-04-29 Last updated: 2024-04-29Bibliographically approved
Hahn, M. & Ahlgren, U. (2023). 3D optical molecular imaging of the rodent pancreas by OPT and LSFM. In: Anna Moore; Ping Wang (Ed.), Type-1 diabetes: methods and protocols (pp. 1-19). New York: Humana Press
Open this publication in new window or tab >>3D optical molecular imaging of the rodent pancreas by OPT and LSFM
2023 (English)In: Type-1 diabetes: methods and protocols / [ed] Anna Moore; Ping Wang, New York: Humana Press, 2023, , p. 19p. 1-19Chapter in book (Refereed)
Abstract [en]

The rodent pancreas is the prevalent model system for preclinical diabetes research. However, due to the compound endocrine–exocrine organization of the gland, with the endocrine islets of Langerhans scattered by the thousands throughout the much greater exocrine parenchyma, stereological assessments of endocrine cell mass, commonly insulin-producing ß-cells, are exceedingly challenging. In recent years, optical mesoscopic imaging techniques such as optical projection tomography (OPT) and light sheet fluorescence microscopy (LSFM) have seen dramatic developments, enabling 3D visualization of fluorescently labeled cells in mm- to cm-sized tissues with μm resolution. Here we present a protocol for 3D visualization and “absolute” quantitative assessments of, for example, islet mass throughout the volume of rodent pancreata with maintained spatial context.

Place, publisher, year, edition, pages
New York: Humana Press, 2023. p. 19
Series
Methods in Molecular Biology, ISSN 1064-3745, E-ISSN 1940-6029 ; 2592
Keywords
Diabetes, Insulin, Islets of Langerhans, Light sheet fluorescence microscopy, Optical clearing, Optical projection tomography, Pancreas, Rodents, Whole mount immunohistochemistry
National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-202060 (URN)10.1007/978-1-0716-2807-2_1 (DOI)36507982 (PubMedID)2-s2.0-85144475952 (Scopus ID)978-1-0716-2806-5 (ISBN)978-1-0716-2809-6 (ISBN)978-1-0716-2807-2 (ISBN)
Available from: 2023-01-03 Created: 2023-01-03 Last updated: 2023-03-23Bibliographically approved
Chotiwan, N., Rosendal, E., Willekens, S. M. A., Schexnaydre, E., Nilsson, E., Lindquist, R., . . . Överby, A. K. (2023). Type I interferon shapes brain distribution and tropism of tick-borne flavivirus. Nature Communications, 14(1), Article ID 2007.
Open this publication in new window or tab >>Type I interferon shapes brain distribution and tropism of tick-borne flavivirus
Show others...
2023 (English)In: Nature Communications, E-ISSN 2041-1723, Vol. 14, no 1, article id 2007Article in journal (Refereed) Published
Abstract [en]

Viral tropism within the brain and the role(s) of vertebrate immune response to neurotropic flaviviruses infection is largely understudied. We combine multimodal imaging (cm-nm scale) with single nuclei RNA-sequencing to study Langat virus in wildtype and interferon alpha/beta receptor knockout (Ifnar-/-) mice to visualize viral pathogenesis and define molecular mechanisms. Whole brain viral infection is imaged by Optical Projection Tomography coregistered to ex vivo MRI. Infection is limited to grey matter of sensory systems in wildtype mice, but extends into white matter, meninges and choroid plexus in Ifnar-/- mice. Cells in wildtype display strong type I and II IFN responses, likely due to Ifnb expressing astrocytes, infiltration of macrophages and Ifng-expressing CD8+ NK cells, whereas in Ifnar-/-, the absence of this response contributes to a shift in cellular tropism towards non-activated resident microglia. Multimodal imaging-transcriptomics exemplifies a powerful way to characterize mechanisms of viral pathogenesis and tropism.

Place, publisher, year, edition, pages
Springer Nature, 2023
National Category
Microbiology in the medical area Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy) Neurosciences
Identifiers
urn:nbn:se:umu:diva-206780 (URN)10.1038/s41467-023-37698-0 (DOI)000967732600009 ()37037810 (PubMedID)2-s2.0-85152115180 (Scopus ID)
Funder
The Kempe Foundations, SMK-1532Knut and Alice Wallenberg Foundation, KAW2015.0284Swedish Research Council, 2018-05851Swedish Research Council, 2017-01307Swedish Research Council, 2020-06224Swedish Research Council, 2021-06602
Available from: 2023-04-24 Created: 2023-04-24 Last updated: 2023-09-05Bibliographically approved
Hahn, M. (2022). Characterizing the pancreatic "isletome": 3D optical imaging to study diabetes. (Doctoral dissertation). Umeå: Umeå University
Open this publication in new window or tab >>Characterizing the pancreatic "isletome": 3D optical imaging to study diabetes
2022 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Tredimensionella analyser av de Langerhanska öarna vid diabetes
Abstract [en]

The pancreas is a specialised multipurpose organ, that can be separated into two major compartments: endocrine and exocrine. The exocrine part makes up the majority of the organ volume and functions to secrete digestive enzymes into the small intestine. Notably, endocrine islets of Langerhans are embedded and scattered in vast numbers throughout the exocrine space. These miniature functional units are composed of different cell types that secrete hormones into the blood stream. The most abundant islet-cell is the insulin-producing β-cell. Highly coordinated, the endocrine cells are the primary regulators of energy homeostasis in the body. Together, the collective islet volume constitutes the pancreatic “isletome”, a synchronised, complex and size-equilibrated system that is able to respond to various metabolic conditions. Indeed, environmental and/or genetic conditions often lead to impaired islet function and/or β-cell destruction leading to elevated blood glucose levels over time and eventually diabetes. 

Diabetes mellitus is a disease that currently affects more than 400 million individuals worldwide. As such, understanding pancreatic disease-related mechanisms is pivotal to the development of new and more effective therapeutic, or even curative, regimens. The deep location of the pancreas in the abdomen and the relatively low resolution of current clinical imaging approaches, however, render the pancreatic islets difficult to study when visually assessing endocrine function. Although non-invasive imaging techniques have yet to reach their full potential, post-mortem studies of the pancreas and rodent disease models offer unique insights into the process of diabetes disease dynamics.

Diabetes induced by streptozotocin (STZ) is a widely used model system in pre-clinical research, where it is generally believed that the b-cells are depleted upon the administration of the drug. Yet, quantification of β-cell volume dynamics and underlying disease mechanisms have not been extensively described. Using optical projection tomography (OPT), light sheet fluorescence microscopy (LSFM) and advanced protocols for ex vivo whole organ three-dimensional (3D) imaging, this study demonstrated that STZ-induced β-cell depletion is modest, primarily affecting large islets, and is not the primary cause for the development of diabetes in STZ-diabetic mice. Combined with islet gene expression studies, the remaining β-cell volume in STZ-diabetic mice displayed a downregulation of glucose transporter type 2 (GLUT2), a transmembrane carrier vital for sensing blood glucose levels. Islet transplantation into the anterior chamber of the eye (ACE) reversed the STZ-induced hyperglycaemia and partially restored islet function, including GLUT2, but did not restore β-cell volume loss. Extensive 3D image datasets were generated as a resource to the research community. The combined results of this study indicated that STZ-induced hyperglycaemia is not caused by β-cell loss, but rather by dysfunctional β-cells and that recovery of islet function is restrained by continuous hyperglycaemia.

3D imaging using OPT has proven to be a reliable technique in quantifying cellular/anatomical features of the mouse pancreas. However, the technique has rarely been applied to patient-derived tissues. Here, a label-free and non-destructive method was developed to assess clinical biopsies within hours of collection. Specifically, this study showed that autofluorescence-based imaging can be used to delineate tumours of the pancreas (pancreatic ductal adenocarcinoma, PDAC) in 3D, which may aid in identifying tumour margins in conjunction with resective surgery. Importantly, the protocol included a reversal pipeline so that other histological workflows could be applied to the same specimen. Furthermore, this study demonstrated that natural fluorescent substances in the endocrine cells provide sufficient contrast when quantifying both the volume and number of islets of Langerhans in the healthy pancreas. Altogether, the developed technique may provide a novel tool for the rapid 3D analysis of pancreatic biopsies that may complement and improve traditional pathological assessments.

With the emergence of islet transplantation networks worldwide, access to fixed pancreatic tissues from diseased donors has dramatically improved. Hereby, the near instant autolysis of the pancreas post-mortem can generally be avoided, which provides the opportunity to quantitatively study the entire gland ex vivo within a conserved spatial context. Yet, mesoscopic 3D imaging of the pancreas (by OPT and/or LSFM) has been limited predominantly due to the obstacle of labelling larger tissue volumes. As such, a simple approach to antibody labelling and cellular imaging was developed in cubic centimetre-sized tissue cuboids that were mapped to the whole organ. By stitching the resultant datasets back into 3D space, this approach demonstrated how essentially any human organ may be analysed in full with high resolution. This technique was applied to pancreata from non-diabetic and type 2 diabetic (T2D) donors, analysing over 200 thousand islets, revealing features of the human pancreas that were not analysed in 3D previously, including high islet dense regions and intra-islet haemorrhaging. Crucially, this new technique may contribute to unveil a wealth of new insights into the complex pathophysiology of the “diabetic pancreas”.

By applying the above method to the entire volume of the human pancreas, the absolute distribution and volume of insulin-positive cells in a pancreas from a donor with longstanding type 1 diabetes (T1D) was demonstrated for the first time. By dividing the 19 cm long organ into smaller pieces, followed by insulin labelling, OPT imaging and reconstruction in 3D space, approximately 173,000 insulin-positive objects were identified. By utilising tissue autofluorescence, the entire organ was reconstructed in 3D, together with blood vessels and ducts. These data indicated several important regional differences in β-cell mass, such as the uncinate process showing the highest density, which potentially reflects key aspects of disease dynamics. Furthermore, regions with a “punctated distribution” of single β-cells in close proximity to each other were identified. Although the significance of these observations needs to be elucidated, we speculate that these regions could be associated with pancreatic regeneration, which might permit the development of new interventions for clinical regenerative processes in the future. Altogether, this study represents the first whole organ account of β-cell distribution at the current level of resolution in an entire organ. As such, it may serve as an important advancement towards detailed whole organ analyses of endocrine cell identity/function, via a wide range of markers, in the study of normal anatomy and pathophysiology of the human pancreas.

Place, publisher, year, edition, pages
Umeå: Umeå University, 2022. p. 92
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 2177
Keywords
3D imaging, fluorescence microscopy, 3D image analysis, technique development, diabetes, Islet of Langerhans, Insulin, β-cell mass, pancreas, anatomy
National Category
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy) Biomedical Laboratory Science/Technology
Research subject
molecular medicine (medical sciences); Medical Biochemistry
Identifiers
urn:nbn:se:umu:diva-193479 (URN)978-91-7855-775-2 (ISBN)978-91-7855-776-9 (ISBN)
Public defence
2022-04-29, Aula Anatomica, BIO.A.206, Biology Building, Umeå University, Umeå, 09:00 (English)
Opponent
Supervisors
Funder
Swedish Research CouncilInsamlingsstiftelsen Diabetes WellnessSwedish Child Diabetes FoundationDiabetesfondenNovo NordiskThe Kempe Foundations
Available from: 2022-04-08 Created: 2022-04-04 Last updated: 2023-04-29Bibliographically approved
Hahn, M., Nord, C., van Krieken, P. P., Berggren, P.-O., Ilegems, E., Cheddad, A. & Ahlgren, U. (2022). Quantitative 3D OPT and LSFM datasets of pancreata from mice with streptozotocin-induced diabetes. Scientific Data, 9, Article ID 558.
Open this publication in new window or tab >>Quantitative 3D OPT and LSFM datasets of pancreata from mice with streptozotocin-induced diabetes
Show others...
2022 (English)In: Scientific Data, E-ISSN 2052-4463, Vol. 9, article id 558Article in journal (Refereed) Published
Abstract [en]

Mouse models for streptozotocin (STZ) induced diabetes probably represent the most widely used systems for preclinical diabetes research, owing to the compound’s toxic effect on pancreatic β-cells. However, a comprehensive view of pancreatic β-cell mass distribution subject to STZ administration is lacking. Previous assessments have largely relied on the extrapolation of stereological sections, which provide limited 3D-spatial and quantitative information. This data descriptor presents multiple ex vivo tomographic optical image datasets of the full β-cell mass distribution in mice subject to single high and multiple low doses of STZ administration, and in glycaemia recovered mice. The data further include information about structural features, such as individual islet β-cell volumes, spatial coordinates, and shape as well as signal intensities for both insulin and GLUT2. Together, they provide the most comprehensive anatomical record of the effects of STZ administration on the islet of Langerhans in mice. As such, this data descriptor may serve as reference material to facilitate the planning, use and (re)interpretation of this widely used disease model.

Place, publisher, year, edition, pages
Nature Publishing Group, 2022
National Category
Endocrinology and Diabetes
Identifiers
urn:nbn:se:umu:diva-193538 (URN)10.1038/s41597-022-01546-5 (DOI)000852384000002 ()36088402 (PubMedID)2-s2.0-85138129001 (Scopus ID)
Funder
Swedish Diabetes AssociationUmeå UniversityFamiljen Erling-Perssons StiftelseEU, FP7, Seventh Framework Programme, 289932EU, FP7, Seventh Framework Programme, 613879Knut and Alice Wallenberg FoundationSwedish Research CouncilNovo Nordisk
Note

Originally included in thesis in manuscript form.

Available from: 2022-04-06 Created: 2022-04-06 Last updated: 2022-10-03Bibliographically approved
Hahn, M., Nord, C., Eriksson, M., Morini, F., Alanentalo, T., Korsgren, O. & Ahlgren, U. (2021). 3D imaging of human organs with micrometer resolution - applied to the endocrine pancreas. Communications Biology, 4(1), Article ID 1063.
Open this publication in new window or tab >>3D imaging of human organs with micrometer resolution - applied to the endocrine pancreas
Show others...
2021 (English)In: Communications Biology, E-ISSN 2399-3642, Vol. 4, no 1, article id 1063Article in journal (Refereed) Published
Abstract [en]

The possibility to quantitatively study specific molecular/cellular features of complete human organs with preserved spatial 3D context would have widespread implications for pre-clinical and clinical medicine. Whereas optical 3D imaging approaches have experienced a formidable revolution, they have remained limited due to current incapacities in obtaining specific labelling within large tissue volumes. We present a simple approach enabling reconstruction of antibody labeled cells within entire human organs with preserved organ context. We demonstrate the utility of the approach by providing volumetric data and 3D distribution of hundreds of thousands of islets of Langerhans within the human pancreas. By assessments of pancreata from non-diabetic and type 2 diabetic individuals, we display previously unrecognized features of the human islet mass distribution and pathology. As such, this method may contribute not only in unraveling new information of the pancreatic anatomy/pathophysiology, but it may be translated to essentially any antibody marker or organ system.

Place, publisher, year, edition, pages
Springer Nature, 2021
National Category
Cell and Molecular Biology Endocrinology and Diabetes
Identifiers
urn:nbn:se:umu:diva-187770 (URN)10.1038/s42003-021-02589-x (DOI)000694906000003 ()2-s2.0-85114856810 (Scopus ID)
Available from: 2021-09-22 Created: 2021-09-22 Last updated: 2023-03-24Bibliographically approved
Davies, W. I. L., Sghari, S., Upton, B. A., Nord, C., Hahn, M., Ahlgren, U., . . . Gunhaga, L. (2021). Distinct opsin 3 (Opn3) expression in the developing nervous system during mammalian embryogenesis. eNeuro, 8(5), Article ID ENEURO.0141-21.2021.
Open this publication in new window or tab >>Distinct opsin 3 (Opn3) expression in the developing nervous system during mammalian embryogenesis
Show others...
2021 (English)In: eNeuro, E-ISSN 2373-2822, Vol. 8, no 5, article id ENEURO.0141-21.2021Article in journal (Refereed) Published
Abstract [en]

Opsin 3 (Opn3) is highly expressed in the adult brain, however, information for spatial and temporal expression patterns during embryogenesis is significantly lacking. Here, an Opn3-eGFP reporter mouse line was used to monitor cell body expression and axonal projections during embryonic and early postnatal to adult stages. By applying 2D and 3D fluorescence imaging techniques, we have identified the onset of Opn3 expression, which predominantly occurred during embryonic stages, in various structures during brain/head development. In ad-dition, this study defines over twenty Opn3-eGFP-positive neural structures never reported before. Opn3-eGFP was first observed at E9.5 in neural regions, including the ganglia that will ultimately form the trigeminal, facial and vestibulocochlear cranial nerves (CNs). As development proceeds, expanded Opn3-eGFP expression coincided with the formation and maturation of critical components of the central and peripheral nervous systems (CNS, PNS), including various motor-sensory tracts, such as the dorsal column-medial lemniscus (DCML) sensory tract, and olfactory, acoustic, and optic tracts. The widespread, yet distinct, detection of Opn3-eGFP already at early embryonic stages suggests that Opn3 might play important functional roles in the developing brain and spinal cord to regulate multiple motor and sensory circuitry systems, including proprio-ception, nociception, ocular movement, and olfaction, as well as memory, mood, and emotion. This study presents a crucial blueprint from which to investigate autonomic and cognitive opsin-dependent neural development and resultant behaviors under physiological and pathophysiological conditions.

Place, publisher, year, edition, pages
Society for Neuroscience, 2021
Keywords
Brain, Development, Encephalopsin, Nervous system, Opn3, OPT
National Category
Neurosciences Developmental Biology
Identifiers
urn:nbn:se:umu:diva-187852 (URN)10.1523/ENEURO.0141-21.2021 (DOI)000704430100013 ()34417283 (PubMedID)2-s2.0-85114912713 (Scopus ID)
Funder
Swedish Research Council, 2017-01430The Kempe Foundations, SMK-1763Swedish Research Council, 2017-01307
Available from: 2021-09-23 Created: 2021-09-23 Last updated: 2023-09-05Bibliographically approved
Serra-Navarro, B., Fernandez-Ruiz, R., García-Alamán, A., Pradas-Juni, M., Fernandez-Rebollo, E., Esteban, Y., . . . Gasa, R. (2021). Gsα-dependent signaling is required for postnatal establishment of a functional β-cell mass. Molecular Metabolism, 53, Article ID 101264.
Open this publication in new window or tab >>Gsα-dependent signaling is required for postnatal establishment of a functional β-cell mass
Show others...
2021 (English)In: Molecular Metabolism, ISSN 2212-8778, Vol. 53, article id 101264Article in journal (Refereed) Published
Abstract [en]

Objective: Early postnatal life is a critical period for the establishment of the functional β-cell mass that will sustain whole-body glucose homeostasis during the lifetime. β cells are formed from progenitors during embryonic development but undergo significant expansion in quantity and attain functional maturity after birth. The signals and pathways involved in these processes are not fully elucidated. Cyclic adenosine monophosphate (cAMP) is an intracellular signaling molecule that is known to regulate insulin secretion, gene expression, proliferation, and survival of adult β cells. The heterotrimeric G protein Gs stimulates the cAMP-dependent pathway by activating adenylyl cyclase. In this study, we sought to explore the role of Gs-dependent signaling in postnatal β-cell development.

Methods: To study Gs-dependent signaling, we generated conditional knockout mice in which the α subunit of the Gs protein (Gsα) was ablated from β-cells using the Cre deleter line Ins1Cre. Mice were characterized in terms of glucose homeostasis, including in vivo glucose tolerance, glucose-induced insulin secretion, and insulin sensitivity. β-cell mass was studied using histomorphometric analysis and optical projection tomography. β-cell proliferation was studied by ki67 and phospho-histone H3 immunostatining, and apoptosis was assessed by TUNEL assay. Gene expression was determined in isolated islets and sorted β cells by qPCR. Intracellular cAMP was studied in isolated islets using HTRF-based technology. The activation status of the cAMP and insulin-signaling pathways was determined by immunoblot analysis of the relevant components of these pathways in isolated islets. In vitro proliferation of dissociated islet cells was assessed by BrdU incorporation.

Results: Elimination of Gsα in β cells led to reduced β-cell mass, deficient insulin secretion, and severe glucose intolerance. These defects were evident by weaning and were associated with decreased proliferation and inadequate expression of key β-cell identity and maturation genes in postnatal β-cells. Additionally, loss of Gsα caused a broad multilevel disruption of the insulin transduction pathway that resulted in the specific abrogation of the islet proliferative response to insulin.

Conclusion: We conclude that Gsα is required for β-cell growth and maturation in the early postnatal stage and propose that this is partly mediated via its crosstalk with insulin signaling. Our findings disclose a tight connection between these two pathways in postnatal β cells, which may have implications for using cAMP-raising agents to promote β-cell regeneration and maturation in diabetes.

Place, publisher, year, edition, pages
Elsevier, 2021
Keywords
cAMP, Cell maturation, Gs, Insulin signaling, Postnatal development, Replication, β-Cell mass
National Category
Endocrinology and Diabetes Cell and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-191152 (URN)10.1016/j.molmet.2021.101264 (DOI)000704022000004 ()34091063 (PubMedID)2-s2.0-85108283081 (Scopus ID)
Available from: 2022-01-10 Created: 2022-01-10 Last updated: 2022-01-10Bibliographically approved
Alanentalo, T., Hahn, M., Willekens, S. M. A. & Ahlgren, U. (2021). Mesoscopic Optical Imaging of the Pancreas: Revisiting Pancreatic Anatomy and Pathophysiology. Frontiers in Endocrinology, 12, Article ID 633063.
Open this publication in new window or tab >>Mesoscopic Optical Imaging of the Pancreas: Revisiting Pancreatic Anatomy and Pathophysiology
2021 (English)In: Frontiers in Endocrinology, E-ISSN 1664-2392, Vol. 12, article id 633063Article, review/survey (Refereed) Published
Abstract [en]

The exocrine-endocrine multipart organization of the pancreas makes it an exceedingly challenging organ to analyze, quantitatively and spatially. Both in rodents and humans, estimates of the pancreatic cellular composition, including beta-cell mass, has been largely relying on the extrapolation of 2D stereological data originating from limited sample volumes. Alternatively, they have been obtained by low resolution non-invasive imaging techniques providing little detail regarding the anatomical organization of the pancreas and its cellular and/or molecular make up. In this mini-review, the state of the art and the future potential of currently existing and emerging high-resolution optical imaging techniques working in the mm-cm range with μm resolution, here referred to as mesoscopic imaging approaches, will be discussed regarding their contribution toward a better understanding of pancreatic anatomy both in normal conditions and in the diabetic setting. In particular, optical projection tomography (OPT) and light sheet fluorescence microscopy (LSFM) imaging of the pancreas and their associated tissue processing and computational analysis protocols will be discussed in the light of their current capabilities and future potential to obtain more detailed 3D-spatial, quantitative, and molecular information of the pancreas.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2021
Keywords
diabetes, light sheet fluorescence microscopy, mesoscopic imaging, optical projection tomography, pancreas
National Category
Endocrinology and Diabetes
Identifiers
urn:nbn:se:umu:diva-182014 (URN)10.3389/fendo.2021.633063 (DOI)000629989000001 ()2-s2.0-85102893401 (Scopus ID)
Available from: 2021-04-06 Created: 2021-04-06 Last updated: 2024-01-17Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-0712-8256

Search in DiVA

Show all publications