1
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van Allen KA, Gang N, Hoyeck MP, Perera I, Zhang D, Atlas E, Lynn FC, Bruin JE. Characterizing the effects of Dechlorane Plus on β-cells: a comparative study across models and species. Islets 2024; 16:2361996. [PMID: 38833523 DOI: 10.1080/19382014.2024.2361996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 05/27/2024] [Indexed: 06/06/2024] Open
Abstract
Epidemiological studies consistently link environmental toxicant exposure with increased Type 2 diabetes risk. Our study investigated the diabetogenic effects of a widely used flame retardant, Dechlorane Plus (DP), on pancreatic β-cells using rodent and human model systems. We first examined pancreas tissues from male mice exposed daily to oral gavage of either vehicle (corn oil) or DP (10, 100, or 1000 μg/kg per day) and fed chow or high fat diet for 28-days in vivo. DP exposure did not affect islet size or endocrine cell composition in either diet group. Next, we assessed the effect of 48-hour exposure to vehicle (DMSO) or DP (1, 10, or 100 nM) in vitro using immortalized rat β-cells (INS-1 832/3), primary mouse and human islets, and human stem-cell derived islet-like cells (SC-islets). In INS-1 832/3 cells, DP did not impact glucose-stimulated insulin secretion (GSIS) but significantly decreased intracellular insulin content. DP had no effect on GSIS in mouse islets or SC-islets but had variable effects on GSIS in human islets depending on the donor. DP alone did not affect insulin content in mouse islets, human islets, or SC-islets, but mouse islets co-exposed to DP and glucolipotoxic (GLT) stress conditions (28.7 mM glucose + 0.5 mM palmitate) had reduced insulin content compared to control conditions. Co-exposure of mouse islets to DP + GLT amplified the upregulation of Slc30a8 compared to GLT alone. Our study highlights the importance and challenges of using different in vitro models for studying chemical toxicity.
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Affiliation(s)
- Kyle A van Allen
- Department of Biology & Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | - Noa Gang
- Department of Biology & Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Myriam P Hoyeck
- Department of Biology & Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | - Ineli Perera
- Department of Biology & Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | - Dahai Zhang
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Ella Atlas
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Francis C Lynn
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Jennifer E Bruin
- Department of Biology & Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
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2
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Šterk M, Zhang Y, Pohorec V, Leitgeb EP, Dolenšek J, Benninger RKP, Stožer A, Kravets V, Gosak M. Network representation of multicellular activity in pancreatic islets: Technical considerations for functional connectivity analysis. PLoS Comput Biol 2024; 20:e1012130. [PMID: 38739680 PMCID: PMC11115366 DOI: 10.1371/journal.pcbi.1012130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 05/23/2024] [Accepted: 05/02/2024] [Indexed: 05/16/2024] Open
Abstract
Within the islets of Langerhans, beta cells orchestrate synchronized insulin secretion, a pivotal aspect of metabolic homeostasis. Despite the inherent heterogeneity and multimodal activity of individual cells, intercellular coupling acts as a homogenizing force, enabling coordinated responses through the propagation of intercellular waves. Disruptions in this coordination are implicated in irregular insulin secretion, a hallmark of diabetes. Recently, innovative approaches, such as integrating multicellular calcium imaging with network analysis, have emerged for a quantitative assessment of the cellular activity in islets. However, different groups use distinct experimental preparations, microscopic techniques, apply different methods to process the measured signals and use various methods to derive functional connectivity patterns. This makes comparisons between findings and their integration into a bigger picture difficult and has led to disputes in functional connectivity interpretations. To address these issues, we present here a systematic analysis of how different approaches influence the network representation of islet activity. Our findings show that the choice of methods used to construct networks is not crucial, although care is needed when combining data from different islets. Conversely, the conclusions drawn from network analysis can be heavily affected by the pre-processing of the time series, the type of the oscillatory component in the signals, and by the experimental preparation. Our tutorial-like investigation aims to resolve interpretational issues, reconcile conflicting views, advance functional implications, and encourage researchers to adopt connectivity analysis. As we conclude, we outline challenges for future research, emphasizing the broader applicability of our conclusions to other tissues exhibiting complex multicellular dynamics.
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Affiliation(s)
- Marko Šterk
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Yaowen Zhang
- Department of Pediatrics, Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
| | - Viljem Pohorec
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | | | - Jurij Dolenšek
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Richard K. P. Benninger
- Department of Bioengineering, Barbara Davis Center for Diabetes, Aurora, Colorado, United States of America
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Andraž Stožer
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Vira Kravets
- Department of Pediatrics, Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
- Department of Bioengineering, Jacobs School of Engineering, University of California, San Diego, La Jolla, California, United States of America
| | - Marko Gosak
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Alma Mater Europaea, Maribor
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3
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Cohrs CM, Chen C, Atkinson MA, Drotar DM, Speier S. Bridging the Gap: Pancreas Tissue Slices From Organ and Tissue Donors for the Study of Diabetes Pathogenesis. Diabetes 2024; 73:11-22. [PMID: 38117999 PMCID: PMC10784654 DOI: 10.2337/dbi20-0018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 10/14/2023] [Indexed: 12/22/2023]
Abstract
Over the last two decades, increased availability of human pancreatic tissues has allowed for major expansions in our understanding of islet biology in health and disease. Indeed, studies of fixed and frozen pancreatic tissues, as well as efforts using viable isolated islets obtained from organ donors, have provided significant insights toward our understanding of diabetes. However, the procedures associated with islet isolation result in distressed cells that have been removed from any surrounding influence. The pancreas tissue slice technology was developed as an in situ approach to overcome certain limitations associated with studies on isolated islets or fixed tissue. In this Perspective, we discuss the value of this novel platform and review how pancreas tissue slices, within a short time, have been integrated in numerous studies of rodent and human islet research. We show that pancreas tissue slices allow for investigations in a less perturbed organ tissue environment, ranging from cellular processes, over peri-islet modulations, to tissue interactions. Finally, we discuss the considerations and limitations of this technology in its future applications. We believe the pancreas tissue slices will help bridge the gap between studies on isolated islets and cells to the systemic conditions by providing new insight into physiological and pathophysiological processes at the organ level. ARTICLE HIGHLIGHTS Human pancreas tissue slices represent a novel platform to study human islet biology in close to physiological conditions. Complementary to established technologies, such as isolated islets, single cells, and histological sections, pancreas tissue slices help bridge our understanding of islet physiology and pathophysiology from single cell to intact organ. Diverse sources of viable human pancreas tissue, each with distinct characteristics to be considered, are available to use in tissue slices for the study of diabetes pathogenesis.
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Affiliation(s)
- Christian M. Cohrs
- Institute of Physiology, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- Paul Langerhans Institute Dresden of Helmholtz Munich at the University Hospital and Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Chunguang Chen
- Institute of Physiology, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- Paul Langerhans Institute Dresden of Helmholtz Munich at the University Hospital and Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Mark A. Atkinson
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida Diabetes Institute, Gainesville, FL
| | - Denise M. Drotar
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida Diabetes Institute, Gainesville, FL
| | - Stephan Speier
- Institute of Physiology, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- Paul Langerhans Institute Dresden of Helmholtz Munich at the University Hospital and Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
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4
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Proteomic Profiling of Intra-Islet Features Reveals Substructure-Specific Protein Signatures. Mol Cell Proteomics 2022; 21:100426. [PMID: 36244662 PMCID: PMC9706166 DOI: 10.1016/j.mcpro.2022.100426] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 08/30/2022] [Accepted: 09/04/2022] [Indexed: 11/11/2022] Open
Abstract
Despite their diminutive size, islets of Langerhans play a large role in maintaining systemic energy balance in the body. New technologies have enabled us to go from studying the whole pancreas to isolated whole islets, to partial islet sections, and now to islet substructures isolated from within the islet. Using a microfluidic nanodroplet-based proteomics platform coupled with laser capture microdissection and field asymmetric waveform ion mobility spectrometry, we present an in-depth investigation of protein profiles specific to features within the islet. These features include the islet-acinar interface vascular tissue, inner islet vasculature, isolated endocrine cells, whole islet with vasculature, and acinar tissue from around the islet. Compared to interface vasculature, unique protein signatures observed in the inner vasculature indicate increased innervation and intra-islet neuron-like crosstalk. We also demonstrate the utility of these data for identifying localized structure-specific drug-target interactions using existing protein/drug binding databases.
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5
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Nigi L, Brusco N, Grieco GE, Fignani D, Licata G, Formichi C, Aiello E, Marselli L, Marchetti P, Krogvold L, Jorgensen KD, Sebastiani G, Dotta F. Increased Expression of Viral Sensor MDA5 in Pancreatic Islets and in Hormone-Negative Endocrine Cells in Recent Onset Type 1 Diabetic Donors. Front Immunol 2022; 13:833141. [PMID: 35359976 PMCID: PMC8963204 DOI: 10.3389/fimmu.2022.833141] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 02/17/2022] [Indexed: 01/22/2023] Open
Abstract
The interaction between genetic and environmental factors determines the development of type 1 diabetes (T1D). Some viruses are capable of infecting and damaging pancreatic β-cells, whose antiviral response could be modulated by specific viral RNA receptors and sensors such as melanoma differentiation associated gene 5 (MDA5), encoded by the IFIH1 gene. MDA5 has been shown to be involved in pro-inflammatory and immunoregulatory outcomes, thus determining the response of pancreatic islets to viral infections. Although the function of MDA5 has been previously well explored, a detailed immunohistochemical characterization of MDA5 in pancreatic tissues of nondiabetic and T1D donors is still missing. In the present study, we used multiplex immunofluorescence imaging analysis to characterize MDA5 expression and distribution in pancreatic tissues obtained from 22 organ donors (10 nondiabetic autoantibody-negative, 2 nondiabetic autoantibody-positive, 8 recent-onset, and 2 long-standing T1D). In nondiabetic control donors, MDA5 was expressed both in α- and β-cells. The colocalization rate imaging analysis showed that MDA5 was preferentially expressed in α-cells. In T1D donors, we observed an increased colocalization rate of MDA5-glucagon with respect to MDA5-insulin in comparison to nondiabetic controls; such increase was more pronounced in recent-onset with respect to long-standing T1D donors. Of note, an increased colocalization rate of MDA5-glucagon was found in insulin-deficient-islets (IDIs) with respect to insulin-containing-islets (ICIs). Strikingly, we detected the presence of MDA5-positive/hormone-negative endocrine islet-like clusters in T1D donors, presumably due to dedifferentiation or neogenesis phenomena. These clusters were identified exclusively in donors with recent disease onset and not in autoantibody-positive nondiabetic donors or donors with long-standing T1D. In conclusion, we showed that MDA5 is preferentially expressed in α-cells, and its expression is increased in recent-onset T1D donors. Finally, we observed that MDA5 may also characterize the phenotype of dedifferentiated or newly forming islet cells, thus opening to novel roles for MDA5 in pancreatic endocrine cells.
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Affiliation(s)
- Laura Nigi
- Diabetes Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
- *Correspondence: Laura Nigi,
| | - Noemi Brusco
- Diabetes Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Giuseppina E. Grieco
- Diabetes Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Daniela Fignani
- Diabetes Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Giada Licata
- Diabetes Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Caterina Formichi
- Diabetes Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Elena Aiello
- Diabetes Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Lorella Marselli
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Lars Krogvold
- Paediatric Department, Oslo University Hospital, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Knut Dahl Jorgensen
- Paediatric Department, Oslo University Hospital, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Guido Sebastiani
- Diabetes Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
| | - Francesco Dotta
- Diabetes Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
- Fondazione Umberto Di Mario, c/o Toscana Life Sciences, Siena, Italy
- Tuscany Centre for Precision Medicine (CReMeP), Siena, Italy
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6
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Marcheva B, Weidemann BJ, Taguchi A, Perelis M, Ramsey KM, Newman MV, Kobayashi Y, Omura C, Manning Fox JE, Lin H, Macdonald PE, Bass J. P2Y1 purinergic receptor identified as a diabetes target in a small-molecule screen to reverse circadian β-cell failure. eLife 2022; 11:e75132. [PMID: 35188462 PMCID: PMC8860442 DOI: 10.7554/elife.75132] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 01/21/2022] [Indexed: 12/18/2022] Open
Abstract
The mammalian circadian clock drives daily oscillations in physiology and behavior through an autoregulatory transcription feedback loop present in central and peripheral cells. Ablation of the core clock within the endocrine pancreas of adult animals impairs the transcription and splicing of genes involved in hormone exocytosis and causes hypoinsulinemic diabetes. Here, we developed a genetically sensitized small-molecule screen to identify druggable proteins and mechanistic pathways involved in circadian β-cell failure. Our approach was to generate β-cells expressing a nanoluciferase reporter within the proinsulin polypeptide to screen 2640 pharmacologically active compounds and identify insulinotropic molecules that bypass the secretory defect in CRISPR-Cas9-targeted clock mutant β-cells. We validated hit compounds in primary mouse islets and identified known modulators of ligand-gated ion channels and G-protein-coupled receptors, including the antihelmintic ivermectin. Single-cell electrophysiology in circadian mutant mouse and human cadaveric islets revealed ivermectin as a glucose-dependent secretagogue. Genetic, genomic, and pharmacological analyses established the P2Y1 receptor as a clock-controlled mediator of the insulinotropic activity of ivermectin. These findings identify the P2Y1 purinergic receptor as a diabetes target based upon a genetically sensitized phenotypic screen.
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Affiliation(s)
- Biliana Marcheva
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
| | - Benjamin J Weidemann
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
| | - Akihiko Taguchi
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
- Division of Endocrinology, Metabolism, Hematological Science and Therapeutics, Department of Bio-Signal Analysis, Yamaguchi University, Graduate School of Medicine, 1-1-1YamaguchiJapan
| | - Mark Perelis
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
- Ionis Pharmaceuticals, IncCarlsbadUnited States
| | - Kathryn Moynihan Ramsey
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
| | - Marsha V Newman
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
| | - Yumiko Kobayashi
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
| | - Chiaki Omura
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
| | - Jocelyn E Manning Fox
- Department of Pharmacology, Alberta Diabetes Institute, University of AlbertaEdmonton, ABCanada
| | - Haopeng Lin
- Department of Pharmacology, Alberta Diabetes Institute, University of AlbertaEdmonton, ABCanada
| | - Patrick E Macdonald
- Department of Pharmacology, Alberta Diabetes Institute, University of AlbertaEdmonton, ABCanada
| | - Joseph Bass
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of MedicineChicagoUnited States
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7
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Walker JT, Saunders DC, Brissova M, Powers AC. The Human Islet: Mini-Organ With Mega-Impact. Endocr Rev 2021; 42:605-657. [PMID: 33844836 PMCID: PMC8476939 DOI: 10.1210/endrev/bnab010] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Indexed: 02/08/2023]
Abstract
This review focuses on the human pancreatic islet-including its structure, cell composition, development, function, and dysfunction. After providing a historical timeline of key discoveries about human islets over the past century, we describe new research approaches and technologies that are being used to study human islets and how these are providing insight into human islet physiology and pathophysiology. We also describe changes or adaptations in human islets in response to physiologic challenges such as pregnancy, aging, and insulin resistance and discuss islet changes in human diabetes of many forms. We outline current and future interventions being developed to protect, restore, or replace human islets. The review also highlights unresolved questions about human islets and proposes areas where additional research on human islets is needed.
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Affiliation(s)
- John T Walker
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Diane C Saunders
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Marcela Brissova
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Alvin C Powers
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.,Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,VA Tennessee Valley Healthcare System, Nashville, Tennessee, USA
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8
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Stožer A, Skelin Klemen M, Gosak M, Križančić Bombek L, Pohorec V, Slak Rupnik M, Dolenšek J. Glucose-dependent activation, activity, and deactivation of beta cell networks in acute mouse pancreas tissue slices. Am J Physiol Endocrinol Metab 2021; 321:E305-E323. [PMID: 34280052 DOI: 10.1152/ajpendo.00043.2021] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 07/09/2021] [Indexed: 12/14/2022]
Abstract
Many details of glucose-stimulated intracellular calcium changes in β cells during activation, activity, and deactivation, as well as their concentration-dependence, remain to be analyzed. Classical physiological experiments indicated that in islets, functional differences between individual cells are largely attenuated, but recent findings suggest considerable intercellular heterogeneity, with some cells possibly coordinating the collective responses. To address the above with an emphasis on heterogeneity and describing the relations between classical physiological and functional network properties, we performed functional multicellular calcium imaging in mouse pancreas tissue slices over a wide range of glucose concentrations. During activation, delays to activation of cells and any-cell-to-first-responder delays are shortened, and the sizes of simultaneously responding clusters increased with increasing glucose concentrations. Exactly the opposite characterized deactivation. The frequency of fast calcium oscillations during activity increased with increasing glucose up to 12 mM glucose concentration, beyond which oscillation duration became longer, resulting in a homogenous increase in active time. In terms of functional connectivity, islets progressed from a very segregated network to a single large functional unit with increasing glucose concentration. A comparison between classical physiological and network parameters revealed that the first-responders during activation had longer active times during plateau and the most active cells during the plateau tended to deactivate later. Cells with the most functional connections tended to activate sooner, have longer active times, and deactivate later. Our findings provide a common ground for recent differing views on β cell heterogeneity and an important baseline for future studies of stimulus-secretion and intercellular coupling.NEW & NOTEWORTHY We assessed concentration-dependence in coupled β cells, degree of functional heterogeneity, and uncovered possible specialized subpopulations during the different phases of the response to glucose at the level of many individual cells. To this aim, we combined acute mouse pancreas tissue slices with functional multicellular calcium imaging over a wide range from threshold (7 mM) and physiological (8 and 9 mM) to supraphysiological (12 and 16 mM) glucose concentrations, classical physiological, and advanced network analyses.
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Affiliation(s)
- Andraž Stožer
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
| | - Maša Skelin Klemen
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
| | - Marko Gosak
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
| | | | - Viljem Pohorec
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
| | - Marjan Slak Rupnik
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- Alma Mater Europaea-European Center Maribor, Maribor, Slovenia
| | - Jurij Dolenšek
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
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9
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Westholm E, Wendt A, Eliasson L. Islet Function in the Pathogenesis of Cystic Fibrosis-Related Diabetes Mellitus. CLINICAL MEDICINE INSIGHTS-ENDOCRINOLOGY AND DIABETES 2021; 14:11795514211031204. [PMID: 34345195 PMCID: PMC8280842 DOI: 10.1177/11795514211031204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 06/22/2021] [Indexed: 12/12/2022]
Abstract
Cystic fibrosis-related diabetes mellitus (CFRD) is the most common non-pulmonary
co-morbidity in cystic fibrosis (CF). CF is caused by mutations in the cystic
fibrosis transmembrane conductance regulator gene (CFTR), which
leads to aberrant luminal fluid secretions in organs such as the lungs and
pancreas. How dysfunctional CFTR leads to CFRD is still under debate. Both
intrinsic effects of dysfunctional CFTR in hormone secreting cells of the islets
and effects of exocrine damage have been proposed. In the current review, we
discuss these non-mutually exclusive hypotheses with a special focus on how
dysfunctional CFTR in endocrine cells may contribute to an altered glucose
homeostasis. We outline the proposed role of CFTR in the molecular pathways of
β-cell insulin secretion and α-cell glucagon secretion, and touch upon the
importance of the exocrine pancreas and intra-pancreatic crosstalk for proper
islet function.
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Affiliation(s)
- Efraim Westholm
- Department of Clinical Sciences in Malmö, Islet Cell Exocytosis, Lund University Diabetes Centre, Lund University, Malmö, Sweden
| | - Anna Wendt
- Department of Clinical Sciences in Malmö, Islet Cell Exocytosis, Lund University Diabetes Centre, Lund University, Malmö, Sweden
| | - Lena Eliasson
- Department of Clinical Sciences in Malmö, Islet Cell Exocytosis, Lund University Diabetes Centre, Lund University, Malmö, Sweden
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10
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Šterk M, Križančić Bombek L, Skelin Klemen M, Slak Rupnik M, Marhl M, Stožer A, Gosak M. NMDA receptor inhibition increases, synchronizes, and stabilizes the collective pancreatic beta cell activity: Insights through multilayer network analysis. PLoS Comput Biol 2021; 17:e1009002. [PMID: 33974632 PMCID: PMC8139480 DOI: 10.1371/journal.pcbi.1009002] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 05/21/2021] [Accepted: 04/26/2021] [Indexed: 12/15/2022] Open
Abstract
NMDA receptors promote repolarization in pancreatic beta cells and thereby reduce glucose-stimulated insulin secretion. Therefore, NMDA receptors are a potential therapeutic target for diabetes. While the mechanism of NMDA receptor inhibition in beta cells is rather well understood at the molecular level, its possible effects on the collective cellular activity have not been addressed to date, even though proper insulin secretion patterns result from well-synchronized beta cell behavior. The latter is enabled by strong intercellular connectivity, which governs propagating calcium waves across the islets and makes the heterogeneous beta cell population work in synchrony. Since a disrupted collective activity is an important and possibly early contributor to impaired insulin secretion and glucose intolerance, it is of utmost importance to understand possible effects of NMDA receptor inhibition on beta cell functional connectivity. To address this issue, we combined confocal functional multicellular calcium imaging in mouse tissue slices with network science approaches. Our results revealed that NMDA receptor inhibition increases, synchronizes, and stabilizes beta cell activity without affecting the velocity or size of calcium waves. To explore intercellular interactions more precisely, we made use of the multilayer network formalism by regarding each calcium wave as an individual network layer, with weighted directed connections portraying the intercellular propagation. NMDA receptor inhibition stabilized both the role of wave initiators and the course of waves. The findings obtained with the experimental antagonist of NMDA receptors, MK-801, were additionally validated with dextrorphan, the active metabolite of the approved drug dextromethorphan, as well as with experiments on NMDA receptor KO mice. In sum, our results provide additional and new evidence for a possible role of NMDA receptor inhibition in treatment of type 2 diabetes and introduce the multilayer network paradigm as a general strategy to examine effects of drugs on connectivity in multicellular systems.
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Affiliation(s)
- Marko Šterk
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
| | | | | | - Marjan Slak Rupnik
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- Alma Mater Europaea–ECM, Maribor, Slovenia
| | - Marko Marhl
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Education, University of Maribor, Maribor, Slovenia
| | - Andraž Stožer
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Marko Gosak
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
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Affiliation(s)
- Sally M Marshall
- Diabetes Research Group, Translational and Clinical Research Institute, Faculty of Clinical Medical Sciences, Newcastle University, 4th Floor William Leech Building, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.
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