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Rutter GA, Gresch A, Delgadillo Silva L, Benninger RKP. Exploring pancreatic beta-cell subgroups and their connectivity. Nat Metab 2024:10.1038/s42255-024-01097-6. [PMID: 39117960 DOI: 10.1038/s42255-024-01097-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 07/05/2024] [Indexed: 08/10/2024]
Abstract
Functional pancreatic islet beta cells are essential to ensure glucose homeostasis across species from zebrafish to humans. These cells show significant heterogeneity, and emerging studies have revealed that connectivity across a hierarchical network is required for normal insulin release. Here, we discuss current thinking and areas of debate around intra-islet connectivity, cellular hierarchies and potential "controlling" beta-cell populations. We focus on methodologies, including comparisons of different cell preparations as well as in vitro and in vivo approaches to imaging and controlling the activity of human and rodent islet preparations. We also discuss the analytical approaches that can be applied to live-cell data to identify and study critical subgroups of cells with a disproportionate role in control Ca2+ dynamics and thus insulin secretion (such as "first responders", "leaders" and "hubs", as defined by Ca2+ responses to glucose stimulation). Possible mechanisms by which this hierarchy is achieved, its physiological relevance and how its loss may contribute to islet failure in diabetes mellitus are also considered. A glossary of terms and links to computational resources are provided.
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Affiliation(s)
- Guy A Rutter
- CHUM Research Center and Faculty of Medicine, University of Montréal, Montréal, QC, Canada.
- Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, UK.
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
| | - Anne Gresch
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Luis Delgadillo Silva
- CHUM Research Center and Faculty of Medicine, University of Montréal, Montréal, QC, Canada
| | - Richard K P Benninger
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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2
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Peng X, Ren H, Yang L, Tong S, Zhou R, Long H, Wu Y, Wang L, Wu Y, Zhang Y, Shen J, Zhang J, Qiu G, Wang J, Han C, Zhang Y, Zhou M, Zhao Y, Xu T, Tang C, Chen Z, Liu H, Chen L. Readily releasable β cells with tight Ca 2+-exocytosis coupling dictate biphasic glucose-stimulated insulin secretion. Nat Metab 2024; 6:238-253. [PMID: 38278946 DOI: 10.1038/s42255-023-00962-0] [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: 05/23/2022] [Accepted: 12/05/2023] [Indexed: 01/28/2024]
Abstract
Biphasic glucose-stimulated insulin secretion (GSIS) is essential for blood glucose regulation, but a mechanistic model incorporating the recently identified islet β cell heterogeneity remains elusive. Here, we show that insulin secretion is spatially and dynamically heterogeneous across the islet. Using a zinc-based fluorophore with spinning-disc confocal microscopy, we reveal that approximately 40% of islet cells, which we call readily releasable β cells (RRβs), are responsible for 80% of insulin exocytosis events. Although glucose up to 18.2 mM fully mobilized RRβs to release insulin synchronously (first phase), even higher glucose concentrations enhanced the sustained secretion from these cells (second phase). Release-incompetent β cells show similarities to RRβs in glucose-evoked Ca2+ transients but exhibit Ca2+-exocytosis coupling deficiency. A decreased number of RRβs and their altered secretory ability are associated with impaired GSIS progression in ob/ob mice. Our data reveal functional heterogeneity at the level of exocytosis among β cells and identify RRβs as a subpopulation of β cells that make a disproportionally large contribution to biphasic GSIS from mouse islets.
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Affiliation(s)
- Xiaohong Peng
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China
- Bioland Laboratory, Guangzhou, China
| | - Huixia Ren
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
- Center for Quantitative Biology and Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Lu Yang
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
- The MOE Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Shiyan Tong
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
| | - Renjie Zhou
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Haochen Long
- School of Software and Microelectronics, Peking University, Beijing, China
| | - Yunxiang Wu
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Lifen Wang
- Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yi Wu
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Yongdeng Zhang
- School of Life Sciences, Westlake University, Hangzhou, China
| | - Jiayu Shen
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Junwei Zhang
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Guohua Qiu
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Jianyong Wang
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Chengsheng Han
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Yulin Zhang
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Mengxuan Zhou
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Yiwen Zhao
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Tao Xu
- Guangzhou National Laboratory, Guangzhou, China
- School of Biomedical Engineering, Guangzhou Medical University, Guangzhou, China
| | - Chao Tang
- Center for Quantitative Biology and Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Zhixing Chen
- National Biomedical Imaging Center, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Huisheng Liu
- Bioland Laboratory, Guangzhou, China.
- Guangzhou National Laboratory, Guangzhou, China.
- School of Biomedical Engineering, Guangzhou Medical University, Guangzhou, China.
| | - Liangyi Chen
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China.
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China.
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3
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Briggs JK, Gresch A, Marinelli I, Dwulet JM, Albers DJ, Kravets V, Benninger RKP. β-cell intrinsic dynamics rather than gap junction structure dictates subpopulations in the islet functional network. eLife 2023; 12:e83147. [PMID: 38018905 PMCID: PMC10803032 DOI: 10.7554/elife.83147] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 11/27/2023] [Indexed: 11/30/2023] Open
Abstract
Diabetes is caused by the inability of electrically coupled, functionally heterogeneous β-cells within the pancreatic islet to provide adequate insulin secretion. Functional networks have been used to represent synchronized oscillatory [Ca2+] dynamics and to study β-cell subpopulations, which play an important role in driving islet function. The mechanism by which highly synchronized β-cell subpopulations drive islet function is unclear. We used experimental and computational techniques to investigate the relationship between functional networks, structural (gap junction) networks, and intrinsic β-cell dynamics in slow and fast oscillating islets. Highly synchronized subpopulations in the functional network were differentiated by intrinsic dynamics, including metabolic activity and KATP channel conductance, more than structural coupling. Consistent with this, intrinsic dynamics were more predictive of high synchronization in the islet functional network as compared to high levels of structural coupling. Finally, dysfunction of gap junctions, which can occur in diabetes, caused decreases in the efficiency and clustering of the functional network. These results indicate that intrinsic dynamics rather than structure drive connections in the functional network and highly synchronized subpopulations, but gap junctions are still essential for overall network efficiency. These findings deepen our interpretation of functional networks and the formation of functional subpopulations in dynamic tissues such as the islet.
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Affiliation(s)
- Jennifer K Briggs
- Department of Bioengineering, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Anne Gresch
- Department of Bioengineering, University of Colorado Anschutz Medical CampusAuroraUnited States
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Isabella Marinelli
- Centre for Systems Modelling and Quantitative Biomedicine, University of BirminghamBirminghamUnited Kingdom
| | - JaeAnn M Dwulet
- Department of Bioengineering, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - David J Albers
- Department of Bioengineering, University of Colorado Anschutz Medical CampusAuroraUnited States
- Department of Biomedical Informatics, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Vira Kravets
- Department of Bioengineering, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Richard KP Benninger
- Department of Bioengineering, University of Colorado Anschutz Medical CampusAuroraUnited States
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical CampusAuroraUnited States
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Šterk M, Dolenšek J, Skelin Klemen M, Križančić Bombek L, Paradiž Leitgeb E, Kerčmar J, Perc M, Slak Rupnik M, Stožer A, Gosak M. Functional characteristics of hub and wave-initiator cells in β cell networks. Biophys J 2023; 122:784-801. [PMID: 36738106 PMCID: PMC10027448 DOI: 10.1016/j.bpj.2023.01.039] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 12/22/2022] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
Islets of Langerhans operate as multicellular networks in which several hundred β cells work in synchrony to produce secretory pulses of insulin, a hormone crucial for controlling metabolic homeostasis. Their collective rhythmic activity is facilitated by gap junctional coupling and affected by their functional heterogeneity, but the details of this robust and coordinated behavior are still not fully understood. Recent advances in multicellular imaging and optogenetic and photopharmacological strategies, as well as in network science, have led to the discovery of specialized β cell subpopulations that were suggested to critically determine the collective dynamics in the islets. In particular hubs, i.e., β cells with many functional connections, are believed to significantly enhance communication capacities of the intercellular network and facilitate an efficient spreading of intercellular Ca2+ waves, whereas wave-initiator cells trigger intercellular signals in their cohorts. Here, we determined Ca2+ signaling characteristics of these two β cell subpopulations and the relationship between them by means of functional multicellular Ca2+ imaging in mouse pancreatic tissue slices in combination with methods of complex network theory. We constructed network layers based on individual Ca2+ waves to identify wave initiators, and functional correlation-based networks to detect hubs. We found that both cell types exhibit a higher-than-average active time under both physiological and supraphysiological glucose concentrations, but also that they differ significantly in many other functional characteristics. Specifically, Ca2+ oscillations in hubs are more regular, and their role appears to be much more stable over time than for initiator cells. Moreover, in contrast to wave initiators, hubs transmit intercellular signals faster than other cells, which implies a stronger intercellular coupling. Our research indicates that hubs and wave-initiator cell subpopulations are both natural features of healthy pancreatic islets, but their functional roles in principle do not overlap and should thus not be considered equal.
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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
| | - Jurij Dolenšek
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia; Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | | | | | | | - Jasmina Kerčmar
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Matjaž Perc
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia; Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan; Alma Mater Europaea, Maribor, Slovenia; Complexity Science Hub Vienna, Vienna, Austria; Department of Physics, Kyung Hee University, Dongdaemun-gu, Seoul, Republic of Korea
| | - Marjan Slak Rupnik
- Faculty of Medicine, University of Maribor, Maribor, Slovenia; Alma Mater Europaea, Maribor, Slovenia; Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Andraž Stožer
- Faculty of Medicine, University of Maribor, Maribor, Slovenia.
| | - 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, Slovenia.
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5
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Chabosseau P, Yong F, Delgadillo-Silva LF, Lee EY, Melhem R, Li S, Gandhi N, Wastin J, Noriega LL, Leclerc I, Ali Y, Hughes JW, Sladek R, Martinez-Sanchez A, Rutter GA. Molecular phenotyping of single pancreatic islet leader beta cells by "Flash-Seq". Life Sci 2023; 316:121436. [PMID: 36706832 DOI: 10.1016/j.lfs.2023.121436] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/11/2023] [Accepted: 01/20/2023] [Indexed: 01/26/2023]
Abstract
AIMS Spatially-organized increases in cytosolic Ca2+ within pancreatic beta cells in the pancreatic islet underlie the stimulation of insulin secretion by high glucose. Recent data have revealed the existence of subpopulations of beta cells including "leaders" which initiate Ca2+ waves. Whether leader cells possess unique molecular features, or localisation, is unknown. MAIN METHODS High speed confocal Ca2+ imaging was used to identify leader cells and connectivity analysis, running under MATLAB and Python, to identify highly connected "hub" cells. To explore transcriptomic differences between beta cell sub-groups, individual leaders or followers were labelled by photo-activation of the cryptic fluorescent protein PA-mCherry and subjected to single cell RNA sequencing ("Flash-Seq"). KEY FINDINGS Distinct Ca2+ wave types were identified in individual islets, with leader cells present in 73 % (28 of 38 islets imaged). Scale-free, power law-adherent behaviour was also observed in 29 % of islets, though "hub" cells in these islets did not overlap with leaders. Transcripts differentially expressed (295; padj < 0.05) between leader and follower cells included genes involved in cilium biogenesis and transcriptional regulation. Providing some support for these findings, ADCY6 immunoreactivity tended to be higher in leader than follower cells, whereas cilia number and length tended to be lower in the former. Finally, leader cells were located significantly closer to delta, but not alpha, cells in Euclidian space than were follower cells. SIGNIFICANCE The existence of both a discrete transcriptome and unique localisation implies a role for these features in defining the specialized function of leaders. These data also raise the possibility that localised signalling between delta and leader cells contributes to the initiation and propagation of islet Ca2+ waves.
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Affiliation(s)
- Pauline Chabosseau
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, QC, Canada
| | - Fiona Yong
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom; Lee Kong Chian Imperial Medical School, Nanyang Technological University, Singapore
| | - Luis F Delgadillo-Silva
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, QC, Canada
| | - Eun Young Lee
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, United States; Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, South Korea
| | - Rana Melhem
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, QC, Canada
| | - Shiying Li
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, QC, Canada
| | - Nidhi Gandhi
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Jules Wastin
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, QC, Canada
| | - Livia Lopez Noriega
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Isabelle Leclerc
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, QC, Canada
| | - Yusuf Ali
- Lee Kong Chian Imperial Medical School, Nanyang Technological University, Singapore
| | - Jing W Hughes
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, United States
| | - Robert Sladek
- Departments of Medicine and Human Genetics, McGill University and Genome Quebec Innovation Centre, Montreal, QC, Canada
| | - Aida Martinez-Sanchez
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Guy A Rutter
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, QC, Canada; Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom; Lee Kong Chian Imperial Medical School, Nanyang Technological University, Singapore.
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6
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Gosak M, Yan-Do R, Lin H, MacDonald PE, Stožer A. Ca2+ Oscillations, Waves, and Networks in Islets From Human Donors With and Without Type 2 Diabetes. Diabetes 2022; 71:2584-2596. [PMID: 36084321 PMCID: PMC9750953 DOI: 10.2337/db22-0004] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 09/01/2022] [Indexed: 01/11/2023]
Abstract
Pancreatic islets are highly interconnected structures that produce pulses of insulin and other hormones, maintaining normal homeostasis of glucose and other nutrients. Normal stimulus-secretion and intercellular coupling are essential to regulated secretory responses, and these hallmarks are known to be altered in diabetes. In the current study, we used calcium imaging of isolated human islets to assess their collective behavior. The activity occurred in the form of calcium oscillations, was synchronized across different regions of islets through calcium waves, and was glucose dependent: higher glucose enhanced the activity, elicited a greater proportion of global calcium waves, and led to denser and less fragmented functional networks. Hub regions were identified in stimulatory conditions, and they were characterized by long active times. Moreover, calcium waves were found to be initiated in different subregions and the roles of initiators and hubs did not overlap. In type 2 diabetes, glucose dependence was retained, but reduced activity, locally restricted waves, and more segregated networks were detected compared with control islets. Interestingly, hub regions seemed to suffer the most by losing a disproportionately large fraction of connections. These changes affected islets from donors with diabetes in a heterogeneous manner.
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Affiliation(s)
- Marko Gosak
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
| | - Richard Yan-Do
- Hong Kong Centre for Cerebro-Cardiovascular Health Engineering, Hong Kong Science Park, Department of Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Canada
| | - Haopeng Lin
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Canada
| | - Patrick E. MacDonald
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Canada
| | - Andraž Stožer
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
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7
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McDonald S, Ray P, Bunn RC, Fowlkes JL, Thrailkill KM, Popescu I. Heterogeneity and altered β-cell identity in the TallyHo model of early-onset type 2 diabetes. Acta Histochem 2022; 124:151940. [PMID: 35969910 DOI: 10.1016/j.acthis.2022.151940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 08/02/2022] [Accepted: 08/03/2022] [Indexed: 11/01/2022]
Abstract
A primary underlying defect makes β-cells "susceptible" to no longer compensate for the peripheral insulin resistance and to trigger the onset of type 2 diabetes (T2D). New evidence suggests that in T2D, β-cells are not destroyed but experience a loss of identity, reverting to a progenitor-like state and largely losing the ability to sense glucose and produce insulin. We assessed (using fluorescence microscopy and histomorphometry correlated with the glycaemic status) the main β-cell identity modifications as diabetes progresses in the TallyHo/JngJ (TH) male mice, a polygenic model of spontaneous T2D, akin to the human phenotype. We found that: 1) conversion to overt diabetes is paralleled by a progressive reduction of insulin-expressing cells and expansion of a glucagon-positive population, together with alteration of islet size and shape; 2) the β-cell population is highly heterogeneous in terms of insulin content and specific transcription factors like PDX1 and NKX6.1, that are gradually lost during diabetes progression; 3) GLUT2 expression is altered early and strongly reduced at late stages of diabetes; 4) an endocrine developmental program dependent on NGN3-expressing progenitors is revived when hyperglycaemia becomes severe; and 5) the re-expression of the EMT-associated factor vimentin occurs as diabetes worsens, representing a possible regenerative response to β-cell loss. Based on these results, we formulated additional hypotheses for the β-cell identity alteration in the TH model, together with several limitations of the study, that constitute future research directions.
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Affiliation(s)
- Sarah McDonald
- Barnstable Brown Diabetes Center, University of Kentucky, College of Medicine, 900S. Limestone, CTW 469, Lexington, KY 40536, USA
| | - Phil Ray
- Barnstable Brown Diabetes Center, University of Kentucky, College of Medicine, 900S. Limestone, CTW 469, Lexington, KY 40536, USA; Department of Pediatric Endocrinology, University of Kentucky, College of Medicine, 2195 Harrodsburg Rd., Lexington, KY 40504, USA
| | - Robert C Bunn
- Barnstable Brown Diabetes Center, University of Kentucky, College of Medicine, 900S. Limestone, CTW 469, Lexington, KY 40536, USA; Department of Pediatric Endocrinology, University of Kentucky, College of Medicine, 2195 Harrodsburg Rd., Lexington, KY 40504, USA
| | - John L Fowlkes
- Barnstable Brown Diabetes Center, University of Kentucky, College of Medicine, 900S. Limestone, CTW 469, Lexington, KY 40536, USA; Department of Pediatric Endocrinology, University of Kentucky, College of Medicine, 2195 Harrodsburg Rd., Lexington, KY 40504, USA
| | - Kathryn M Thrailkill
- Barnstable Brown Diabetes Center, University of Kentucky, College of Medicine, 900S. Limestone, CTW 469, Lexington, KY 40536, USA; Department of Pediatric Endocrinology, University of Kentucky, College of Medicine, 2195 Harrodsburg Rd., Lexington, KY 40504, USA
| | - Iuliana Popescu
- Barnstable Brown Diabetes Center, University of Kentucky, College of Medicine, 900S. Limestone, CTW 469, Lexington, KY 40536, USA.
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8
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Stožer A, Šterk M, Paradiž Leitgeb E, Markovič R, Skelin Klemen M, Ellis CE, Križančić Bombek L, Dolenšek J, MacDonald PE, Gosak M. From Isles of Königsberg to Islets of Langerhans: Examining the Function of the Endocrine Pancreas Through Network Science. Front Endocrinol (Lausanne) 2022; 13:922640. [PMID: 35784543 PMCID: PMC9240343 DOI: 10.3389/fendo.2022.922640] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 05/16/2022] [Indexed: 12/12/2022] Open
Abstract
Islets of Langerhans are multicellular microorgans located in the pancreas that play a central role in whole-body energy homeostasis. Through secretion of insulin and other hormones they regulate postprandial storage and interprandial usage of energy-rich nutrients. In these clusters of hormone-secreting endocrine cells, intricate cell-cell communication is essential for proper function. Electrical coupling between the insulin-secreting beta cells through gap junctions composed of connexin36 is particularly important, as it provides the required, most important, basis for coordinated responses of the beta cell population. The increasing evidence that gap-junctional communication and its modulation are vital to well-regulated secretion of insulin has stimulated immense interest in how subpopulations of heterogeneous beta cells are functionally arranged throughout the islets and how they mediate intercellular signals. In the last decade, several novel techniques have been proposed to assess cooperation between cells in islets, including the prosperous combination of multicellular imaging and network science. In the present contribution, we review recent advances related to the application of complex network approaches to uncover the functional connectivity patterns among cells within the islets. We first provide an accessible introduction to the basic principles of network theory, enumerating the measures characterizing the intercellular interactions and quantifying the functional integration and segregation of a multicellular system. Then we describe methodological approaches to construct functional beta cell networks, point out possible pitfalls, and specify the functional implications of beta cell network examinations. We continue by highlighting the recent findings obtained through advanced multicellular imaging techniques supported by network-based analyses, giving special emphasis to the current developments in both mouse and human islets, as well as outlining challenges offered by the multilayer network formalism in exploring the collective activity of islet cell populations. Finally, we emphasize that the combination of these imaging techniques and network-based analyses does not only represent an innovative concept that can be used to describe and interpret the physiology of islets, but also provides fertile ground for delineating normal from pathological function and for quantifying the changes in islet communication networks associated with the development of diabetes mellitus.
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Affiliation(s)
- Andraž Stožer
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Marko Šterk
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
| | - Eva Paradiž Leitgeb
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Rene Markovič
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Institute of Mathematics and Physics, Faculty of Electrical Engineering and Computer Science, University of Maribor, Maribor, Slovenia
| | - Maša Skelin Klemen
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Cara E. Ellis
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | | | - Jurij Dolenšek
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
| | - Patrick E. MacDonald
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - Marko Gosak
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
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9
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10
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Benninger RKP, Kravets V. The physiological role of β-cell heterogeneity in pancreatic islet function. Nat Rev Endocrinol 2022; 18:9-22. [PMID: 34667280 PMCID: PMC8915749 DOI: 10.1038/s41574-021-00568-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/07/2021] [Indexed: 01/03/2023]
Abstract
Endocrine cells within the pancreatic islets of Langerhans are heterogeneous in terms of transcriptional profile, protein expression and the regulation of hormone release. Even though this heterogeneity has long been appreciated, only within the past 5 years have detailed molecular analyses led to an improved understanding of its basis. Although we are beginning to recognize why some subpopulations of endocrine cells are phenotypically different to others, arguably the most important consideration is how this heterogeneity affects the regulation of hormone release to control the homeostasis of glucose and other energy-rich nutrients. The focus of this Review is the description of how endocrine cell heterogeneity (and principally that of insulin-secreting β-cells) affects the regulation of hormone secretion within the islets of Langerhans. This discussion includes an overview of the functional characteristics of the different islet cell subpopulations and describes how they can communicate to influence islet function under basal and glucose-stimulated conditions. We further discuss how changes to the specific islet cell subpopulations or their numbers might underlie islet dysfunction in type 2 diabetes mellitus. We conclude with a discussion of several key open questions regarding the physiological role of islet cell heterogeneity.
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Affiliation(s)
- Richard K P Benninger
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
| | - Vira Kravets
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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11
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Korošak D, Jusup M, Podobnik B, Stožer A, Dolenšek J, Holme P, Rupnik MS. Autopoietic Influence Hierarchies in Pancreatic β Cells. PHYSICAL REVIEW LETTERS 2021; 127:168101. [PMID: 34723613 DOI: 10.1103/physrevlett.127.168101] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
β cells are biologically essential for humans and other vertebrates. Because their functionality arises from cell-cell interactions, they are also a model system for collective organization among cells. There are currently two contradictory pictures of this organization: the hub-cell idea pointing at leaders who coordinate the others, and the electrophysiological theory describing all cells as equal. We use new data and computational modeling to reconcile these pictures. We find via a network representation of interacting β cells that leaders emerge naturally (confirming the hub-cell idea), yet all cells can take the hub role following a perturbation (in line with electrophysiology).
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Affiliation(s)
- Dean Korošak
- Institute of Physiology, Faculty of Medicine, University of Maribor, 2000 Maribor, Slovenia
- Faculty of Civil Engineering, Transportation Engineering and Architecture, University of Maribor, 2000 Maribor, Slovenia
| | - Marko Jusup
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovative Research, Tokyo Institute of Technology, Tokyo 152-8552, Japan
| | - Boris Podobnik
- Faculty of Civil Engineering, University of Rijeka, 51000 Rijeka, Croatia
- Center for Polymer Studies, Boston University, Boston, Massachusetts 02215, USA
- Zagreb School of Economics and Management, 10000 Zagreb, Croatia
- Luxembourg School of Business, 2453 Luxembourg, Luxembourg
- Faculty of Information Studies in Novo mesto, 8000 Novo Mesto, Slovenia
| | - Andraž Stožer
- Institute of Physiology, Faculty of Medicine, University of Maribor, 2000 Maribor, Slovenia
| | - Jurij Dolenšek
- Institute of Physiology, Faculty of Medicine, University of Maribor, 2000 Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, 2000 Maribor, Slovenia
| | - Petter Holme
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovative Research, Tokyo Institute of Technology, Tokyo 152-8552, Japan
| | - Marjan Slak Rupnik
- Institute of Physiology, Faculty of Medicine, University of Maribor, 2000 Maribor, Slovenia
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
- Alma Mater Europaea-European Center Maribor, 2000 Maribor, Slovenia
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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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13
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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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Small subpopulations of β-cells do not drive islet oscillatory [Ca2+] dynamics via gap junction communication. PLoS Comput Biol 2021; 17:e1008948. [PMID: 33939712 PMCID: PMC8118513 DOI: 10.1371/journal.pcbi.1008948] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 05/13/2021] [Accepted: 04/07/2021] [Indexed: 12/16/2022] Open
Abstract
The islets of Langerhans exist as multicellular networks that regulate blood glucose levels. The majority of cells in the islet are excitable, insulin-producing β-cells that are electrically coupled via gap junction channels. β-cells are known to display heterogeneous functionality. However, due to gap junction coupling, β-cells show coordinated [Ca2+] oscillations when stimulated with glucose, and global quiescence when unstimulated. Small subpopulations of highly functional β-cells have been suggested to control [Ca2+] dynamics across the islet. When these populations were targeted by optogenetic silencing or photoablation, [Ca2+] dynamics across the islet were largely disrupted. In this study, we investigated the theoretical basis of these experiments and how small populations can disproportionality control islet [Ca2+] dynamics. Using a multicellular islet model, we generated normal, skewed or bimodal distributions of β-cell heterogeneity. We examined how islet [Ca2+] dynamics were disrupted when cells were targeted via hyperpolarization or populations were removed; to mimic optogenetic silencing or photoablation, respectively. Targeted cell populations were chosen based on characteristics linked to functional subpopulation, including metabolic rate of glucose oxidation or [Ca2+] oscillation frequency. Islets were susceptible to marked suppression of [Ca2+] when ~10% of cells with high metabolic activity were hyperpolarized; where hyperpolarizing cells with normal metabolic activity had little effect. However, when highly metabolic cells were removed from the model, [Ca2+] oscillations remained. Similarly, when ~10% of cells with either the highest frequency or earliest elevations in [Ca2+] were removed from the islet, the [Ca2+] oscillation frequency remained largely unchanged. Overall, these results indicate small populations of β-cells with either increased metabolic activity or increased frequency are unable to disproportionately control islet-wide [Ca2+] via gap junction coupling. Therefore, we need to reconsider the physiological basis for such small β-cell populations or the mechanism by which they may be acting to control normal islet function. Many biological systems can be studied using network theory. How heterogeneous cell subpopulations come together to create complex multicellular behavior is of great value in understanding function and dysfunction in tissues. The pancreatic islet of Langerhans is a highly coupled structure that is important for maintaining blood glucose homeostasis. β-cell electrical activity is coordinated via gap junction communication. The function of the insulin-producing β-cell within the islet is disrupted in diabetes. As such, to understand the causes of islet dysfunction we need to understand how different cells within the islet contribute to its overall function via gap junction coupling. Using a computational model of β-cell electrophysiology, we investigated how small highly functional β-cell populations within the islet contribute to its function. We found that when small populations with greater functionality were introduced into the islet, they displayed signatures of this enhanced functionality. However, when these cells were removed, the islet, retained near-normal function. Thus, in a highly coupled system, such as an islet, the heterogeneity of cells allows small subpopulations to be dispensable, and thus their absence is unable to disrupt the larger cellular network. These findings can be applied to other electrical systems that have heterogeneous cell populations.
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Hogan JP, Peercy BE. Flipping the switch on the hub cell: Islet desynchronization through cell silencing. PLoS One 2021; 16:e0248974. [PMID: 33831017 PMCID: PMC8031451 DOI: 10.1371/journal.pone.0248974] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 03/08/2021] [Indexed: 11/18/2022] Open
Abstract
Pancreatic β cells, responsible for secreting insulin into the bloodstream and maintaining glucose homeostasis, are organized in the islets of Langerhans as clusters of electrically coupled cells. Gap junctions, connecting neighboring cells, coordinate the behavior of the islet, leading to the synchronized oscillations in the intracellular calcium and insulin secretion in healthy islets. Recent experimental work has shown that silencing special hub cells can lead to a disruption in the coordinated behavior, calling into question the democratic paradigm of islet insulin secretion with more or less equal input from each β cell. Islets were shown to have scale-free functional connectivity and a hub cell whose silencing would lead to a loss of functional connectivity and activity in the islet. A mechanistic model representing the electrical and calcium dynamics of β cells during insulin secretion was applied to a network of cells connected by gap junctions to test the hypothesis of hub cells. Functional connectivity networks were built from the simulated calcium traces, with some networks classified as scale-free, confirming experimental results. Potential hub cells were identified using previously defined centrality measures, but silencing them was unable to desynchronize the islet. Instead, switch cells, which were able to turn off the activity of the islet but were not highly functionally connected, were found via systematically silencing each cell in the network.
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Affiliation(s)
- Janita P. Hogan
- Department of Mathematics & Statistics, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
| | - Bradford E. Peercy
- Department of Mathematics & Statistics, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
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Weitz J, Menegaz D, Caicedo A. Deciphering the Complex Communication Networks That Orchestrate Pancreatic Islet Function. Diabetes 2021; 70:17-26. [PMID: 33355306 PMCID: PMC7881851 DOI: 10.2337/dbi19-0033] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 10/01/2020] [Indexed: 12/27/2022]
Abstract
Pancreatic islets are clusters of hormone-secreting endocrine cells that rely on intricate cell-cell communication mechanisms for proper function. The importance of multicellular cooperation in islet cell physiology was first noted nearly 30 years ago in seminal studies showing that hormone secretion from endocrine cell types is diminished when these cells are dispersed. These studies showed that reestablishing cellular contacts in so-called pseudoislets caused endocrine cells to regain hormone secretory function. This not only demonstrated that cooperation between islet cells is highly synergistic but also gave birth to the field of pancreatic islet organoids. Here we review recent advances related to the mechanisms of islet cell cross talk. We first describe new developments that revise current notions about purinergic and GABA signaling in islets. Then we comment on novel multicellular imaging studies that are revealing emergent properties of islet communication networks. We finish by highlighting and discussing recent synthetic approaches that use islet organoids of varied cellular composition to interrogate intraislet signaling mechanisms. This reverse engineering of islets not only will shed light on the mechanisms of intraislet signaling and define communication networks but also may guide efforts aimed at restoring islet function and β-cell mass in diabetes.
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Affiliation(s)
- Jonathan Weitz
- Department of Medicine, University of Miami Leonard M. Miller School of Medicine, Miami, FL
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, FL
| | - Danusa Menegaz
- Department of Medicine, University of Miami Leonard M. Miller School of Medicine, Miami, FL
| | - Alejandro Caicedo
- Department of Medicine, University of Miami Leonard M. Miller School of Medicine, Miami, FL
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, FL
- Department of Physiology and Biophysics, University of Miami Leonard M. Miller School of Medicine, Miami, FL
- Program in Neuroscience, University of Miami Leonard M. Miller School of Medicine, Miami, FL
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Satin LS, Rorsman P. Response to Comment on Satin et al. "Take Me To Your Leader": An Electrophysiological Appraisal of the Role of Hub Cells in Pancreatic Islets. Diabetes 2020;69:830-836. Diabetes 2020; 69:e12-e13. [PMID: 32820057 PMCID: PMC7809710 DOI: 10.2337/dbi20-0027] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Leslie S Satin
- Department of Pharmacology, Brehm Center for Diabetes Research, Medical School, University of Michigan, Ann Arbor, MI
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, and Churchill Hospital, Oxford, U.K
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