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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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Paradiž Leitgeb E, Kerčmar J, Križančić Bombek L, Pohorec V, Skelin Klemen M, Slak Rupnik M, Gosak M, Dolenšek J, Stožer A. Exendin-4 affects calcium signalling predominantly during activation and activity of beta cell networks in acute mouse pancreas tissue slices. Front Endocrinol (Lausanne) 2024; 14:1315520. [PMID: 38292770 PMCID: PMC10826511 DOI: 10.3389/fendo.2023.1315520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 12/22/2023] [Indexed: 02/01/2024] Open
Abstract
Tight control of beta cell stimulus-secretion coupling is crucial for maintaining homeostasis of energy-rich nutrients. While glucose serves as a primary regulator of this process, incretins augment beta cell function, partly by enhancing cytosolic [Ca2+] dynamics. However, the details of how precisely they affect beta cell recruitment during activation, their active time, and functional connectivity during plateau activity, and how they influence beta cell deactivation remain to be described. Performing functional multicellular Ca2+ imaging in acute mouse pancreas tissue slices enabled us to systematically assess the effects of the GLP-1 receptor agonist exendin-4 (Ex-4) simultaneously in many coupled beta cells with high resolution. In otherwise substimulatory glucose, Ex-4 was able to recruit approximately a quarter of beta cells into an active state. Costimulation with Ex-4 and stimulatory glucose shortened the activation delays and accelerated beta cell activation dynamics. More specifically, active time increased faster, and the time required to reach half-maximal activation was effectively halved in the presence of Ex-4. Moreover, the active time and regularity of [Ca2+]IC oscillations increased, especially during the first part of beta cell response. In contrast, subsequent addition of Ex-4 to already active cells did not significantly enhance beta cell activity. Network analyses further confirmed increased connectivity during activation and activity in the presence of Ex-4, with hub cell roles remaining rather stable in both control experiments and experiments with Ex-4. Interestingly, Ex-4 demonstrated a biphasic effect on deactivation, slightly prolonging beta cell activity at physiological concentrations and shortening deactivation delays at supraphysiological concentrations. In sum, costimulation by Ex-4 and glucose increases [Ca2+]IC during beta cell activation and activity, indicating that the effect of incretins may, to an important extent, be explained by enhanced [Ca2+]IC signals. During deactivation, previous incretin stimulation does not critically prolong cellular activity, which corroborates their low risk of hypoglycemia.
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Affiliation(s)
- Eva Paradiž Leitgeb
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Jasmina Kerčmar
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | | | - Vilijem Pohorec
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Maša Skelin Klemen
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Marjan Slak Rupnik
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- Alma Mater Europaea-European Center Maribor, Maribor, Slovenia
| | - Marko Gosak
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Alma Mater Europaea-European Center Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
| | - Jurij Dolenšek
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
| | - Andraž Stožer
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
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Šterk M, Barać U, Stožer A, Gosak M. Both electrical and metabolic coupling shape the collective multimodal activity and functional connectivity patterns in beta cell collectives: A computational model perspective. Phys Rev E 2023; 108:054409. [PMID: 38115462 DOI: 10.1103/physreve.108.054409] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 10/20/2023] [Indexed: 12/21/2023]
Abstract
Pancreatic beta cells are coupled excitable oscillators that synchronize their activity via different communication pathways. Their oscillatory activity manifests itself on multiple timescales and consists of bursting electrical activity, subsequent oscillations in the intracellular Ca^{2+}, as well as oscillations in metabolism and exocytosis. The coordination of the intricate activity on the multicellular level plays a key role in the regulation of physiological pulsatile insulin secretion and is incompletely understood. In this paper, we investigate theoretically the principles that give rise to the synchronized activity of beta cell populations by building up a phenomenological multicellular model that incorporates the basic features of beta cell dynamics. Specifically, the model is composed of coupled slow and fast oscillatory units that reflect metabolic processes and electrical activity, respectively. Using a realistic description of the intercellular interactions, we study how the combination of electrical and metabolic coupling generates collective rhythmicity and shapes functional beta cell networks. It turns out that while electrical coupling solely can synchronize the responses, the addition of metabolic interactions further enhances coordination, the spatial range of interactions increases the number of connections in the functional beta cell networks, and ensures a better consistency with experimental findings. Moreover, our computational results provide additional insights into the relationship between beta cell heterogeneity, their activity profiles, and functional connectivity, supplementing thereby recent experimental results on endocrine networks.
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Affiliation(s)
- Marko Šterk
- Department of Physics, Faculty of Natural Sciences and Mathematics, Koroška cesta 160, University of Maribor, 2000 Maribor, Slovenia
- Institute of Physiology, Faculty of Medicine, Taborska ulica 8, University of Maribor, 2000 Maribor, Slovenia
- Alma Mater Europaea, Slovenska ulica 17, 2000 Maribor, Slovenia
| | - Uroš Barać
- Department of Physics, Faculty of Natural Sciences and Mathematics, Koroška cesta 160, University of Maribor, 2000 Maribor, Slovenia
| | - Andraž Stožer
- Institute of Physiology, Faculty of Medicine, Taborska ulica 8, University of Maribor, 2000 Maribor, Slovenia
| | - Marko Gosak
- Department of Physics, Faculty of Natural Sciences and Mathematics, Koroška cesta 160, University of Maribor, 2000 Maribor, Slovenia
- Institute of Physiology, Faculty of Medicine, Taborska ulica 8, University of Maribor, 2000 Maribor, Slovenia
- Alma Mater Europaea, Slovenska ulica 17, 2000 Maribor, Slovenia
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Jaffredo M, Krentz NAJ, Champon B, Duff CE, Nawaz S, Beer N, Honore C, Clark A, Rorsman P, Lang J, Gloyn AL, Raoux M, Hastoy B. Electrophysiological characterisation of iPSC-derived human β-like cells and an SLC30A8 disease model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.17.561014. [PMID: 37905040 PMCID: PMC10614917 DOI: 10.1101/2023.10.17.561014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
iPSC-derived human β-like cells (BLC) hold promise for both therapy and disease modelling, but their generation remains challenging and their functional analyses beyond transcriptomic and morphological assessments remain limited. Here, we validate an approach using multicellular and single cell electrophysiological tools to evaluate BLCs functions. The Multi-Electrode Arrays (MEAs) measuring the extracellular electrical activity revealed that BLCs are electrically coupled, produce slow potential (SP) signals like primary β-cells that are closely linked to insulin secretion. We also used high-resolution single-cell patch-clamp measurements to capture the exocytotic properties, and characterize voltage-gated sodium and calcium currents. These were comparable to those in primary β and EndoC-βH1 cells. The KATP channel conductance is greater than in human primary β cells which may account for the limited glucose responsiveness observed with MEA. We used MEAs to study the impact of the type 2 diabetes protective SLC30A8 allele (p.Lys34Serfs*50) and found that BLCs with this allele have stronger electrical coupling. Our data suggest that with an adapted approach BLCs from pioneer protocol can be used to evaluate the functional impact of genetic variants on β-cell function and coupling.
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Affiliation(s)
- Manon Jaffredo
- University of Bordeaux, CNRS, Institute of Chemistry and Biology of Membranes and Nano-objects, UMR 5248, Pessac, France
| | - Nicole A. J. Krentz
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Department of Pediatrics, Stanford School of Medicine, Stanford University, CA, USA
| | - Benoite Champon
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Claire E. Duff
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Sameena Nawaz
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicola Beer
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Anne Clark
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Jochen Lang
- University of Bordeaux, CNRS, Institute of Chemistry and Biology of Membranes and Nano-objects, UMR 5248, Pessac, France
| | - Anna L. Gloyn
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Department of Pediatrics, Stanford School of Medicine, Stanford University, CA, USA
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Matthieu Raoux
- University of Bordeaux, CNRS, Institute of Chemistry and Biology of Membranes and Nano-objects, UMR 5248, Pessac, France
| | - Benoit Hastoy
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
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Raoux M, Lablanche S, Jaffredo M, Pirog A, Benhamou PY, Lebreton F, Wojtusciszyn A, Bosco D, Berney T, Renaud S, Lang J, Catargi B. Islets-on-Chip: A Tool for Real-Time Assessment of Islet Function Prior to Transplantation. Transpl Int 2023; 36:11512. [PMID: 37885808 PMCID: PMC10598278 DOI: 10.3389/ti.2023.11512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 09/28/2023] [Indexed: 10/28/2023]
Abstract
Islet transplantation improves metabolic control in patients with unstable type 1 diabetes. Clinical outcomes have been improving over the last decade, and the widely used beta-score allows the evaluation of transplantation results. However, predictive pre-transplantation criteria of islet quality for clinical outcomes are lacking. In this proof-of-concept study, we examined whether characterization of the electrical activity of donor islets could provide a criterion. Aliquots of 8 human donor islets from the STABILOT study, sampled from islet preparations before transplantation, were characterized for purity and split for glucose-induced insulin secretion and electrical activity using multi-electrode-arrays. The latter tests glucose concentration dependencies, biphasic activity, hormones, and drug effects (adrenalin, GLP-1, glibenclamide) and provides a ranking of CHIP-scores from 1 to 6 (best) based on electrical islet activity. The analysis was performed online in real time using a dedicated board or offline. Grouping of beta-scores and CHIP-scores with high, intermediate, and low values was observed. Further analysis indicated correlation between CHIP-score and beta-score, although significance was not attained (R = 0.51, p = 0.1). This novel approach is easily implantable in islet isolation units and might provide means for the prediction of clinical outcomes. We acknowledge the small cohort size as the limitation of this pilot study.
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Affiliation(s)
- Matthieu Raoux
- University of Bordeaux, CNRS, Institute of Chemistry and Biology of Membranes and Nano-Objects, UMR 5248, Pessac, France
| | - Sandrine Lablanche
- University of Grenoble Alpes, Clinique d’Endocrinologie, Diabétologie, Maladies Métaboliques, CHU Grenoble Alpes, U1055 INSERM, Grenoble, France
| | - Manon Jaffredo
- University of Bordeaux, CNRS, Institute of Chemistry and Biology of Membranes and Nano-Objects, UMR 5248, Pessac, France
| | - Antoine Pirog
- University of Bordeaux, CNRS, Bordeaux INP, Laboratoire de l’Intégration du Matériau au Système, IMS UMR 5218, Talence, France
| | - Pierre-Yves Benhamou
- University of Grenoble Alpes, Clinique d’Endocrinologie, Diabétologie, Maladies Métaboliques, CHU Grenoble Alpes, U1055 INSERM, Grenoble, France
| | - Fanny Lebreton
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals, University of Geneva, Geneva, Switzerland
| | - Anne Wojtusciszyn
- Centre Hospitalier de Montpellier, Service d’Endocrinologie, Université de Montpellier, Montpellier, France
| | - Domenico Bosco
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals, University of Geneva, Geneva, Switzerland
| | - Thierry Berney
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals, University of Geneva, Geneva, Switzerland
| | - Sylvie Renaud
- University of Bordeaux, CNRS, Bordeaux INP, Laboratoire de l’Intégration du Matériau au Système, IMS UMR 5218, Talence, France
| | - Jochen Lang
- University of Bordeaux, CNRS, Institute of Chemistry and Biology of Membranes and Nano-Objects, UMR 5248, Pessac, France
| | - Bogdan Catargi
- Service d’Endocrinologie-Diabétologie, Hôpital St André, CHU de Bordeaux, Bordeaux, France
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Tariq M, de Souza AH, Bensellam M, Chae H, Jaffredo M, Close AF, Deglasse JP, Santos LRB, Buemi A, Mourad NI, Wojtusciszyn A, Raoux M, Gilon P, Broca C, Jonas JC. Prolonged culture of human pancreatic islets under glucotoxic conditions changes their acute beta cell calcium and insulin secretion glucose response curves from sigmoid to bell-shaped. Diabetologia 2023; 66:709-723. [PMID: 36459178 DOI: 10.1007/s00125-022-05842-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 10/18/2022] [Indexed: 12/04/2022]
Abstract
AIMS/HYPOTHESIS The rapid remission of type 2 diabetes by a diet very low in energy correlates with a marked improvement in glucose-stimulated insulin secretion (GSIS), emphasising the role of beta cell dysfunction in the early stages of the disease. In search of novel mechanisms of beta cell dysfunction after long-term exposure to mild to severe glucotoxic conditions, we extensively characterised the alterations in insulin secretion and upstream coupling events in human islets cultured for 1-3 weeks at ~5, 8, 10 or 20 mmol/l glucose and subsequently stimulated by an acute stepwise increase in glucose concentration. METHODS Human islets from 49 non-diabetic donors (ND-islets) and six type 2 diabetic donors (T2D-islets) were obtained from five isolation centres. After shipment, the islets were precultured for 3-7 days in RPMI medium containing ~5 mmol/l glucose and 10% (vol/vol) heat-inactivated FBS with selective islet picking at each medium renewal. Islets were then cultured for 1-3 weeks in RPMI containing ~5, 8, 10 or 20 mmol/l glucose before measurement of insulin secretion during culture, islet insulin and DNA content, beta cell apoptosis and cytosolic and mitochondrial glutathione redox state, and assessment of dynamic insulin secretion and upstream coupling events during acute stepwise stimulation with glucose [NAD(P)H autofluorescence, ATP/(ATP+ADP) ratio, electrical activity, cytosolic Ca2+ concentration ([Ca2+]c)]. RESULTS Culture of ND-islets for 1-3 weeks at 8, 10 or 20 vs 5 mmol/l glucose did not significantly increase beta cell apoptosis or oxidative stress but decreased insulin content in a concentration-dependent manner and increased beta cell sensitivity to subsequent acute stimulation with glucose. Islet glucose responsiveness was higher after culture at 8 or 10 vs 5 mmol/l glucose and markedly reduced after culture at 20 vs 5 mmol/l glucose. In addition, the [Ca2+]c and insulin secretion responses to acute stepwise stimulation with glucose were no longer sigmoid but bell-shaped, with maximal stimulation at 5 or 10 mmol/l glucose and rapid sustained inhibition above that concentration. Such paradoxical inhibition was, however, no longer observed when islets were acutely depolarised by 30 mmol/l extracellular K+. The glucotoxic alterations of beta cell function were fully reversible after culture at 5 mmol/l glucose and were mimicked by pharmacological activation of glucokinase during culture at 5 mmol/l glucose. Similar results to those seen in ND-islets were obtained in T2D-islets, except that their rate of insulin secretion during culture at 8 and 20 mmol/l glucose was lower, their cytosolic glutathione oxidation increased after culture at 8 and 20 mmol/l glucose, and the alterations in GSIS and upstream coupling events were greater after culture at 8 mmol/l glucose. CONCLUSIONS/INTERPRETATION Prolonged culture of human islets under moderate to severe glucotoxic conditions markedly increased their glucose sensitivity and revealed a bell-shaped acute glucose response curve for changes in [Ca2+]c and insulin secretion, with maximal stimulation at 5 or 10 mmol/l glucose and rapid inhibition above that concentration. This novel glucotoxic alteration may contribute to beta cell dysfunction in type 2 diabetes independently from a detectable increase in beta cell apoptosis.
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Affiliation(s)
- Mohammad Tariq
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain, Brussels, Belgium
- Lund University Diabetes Centre, Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Arnaldo H de Souza
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain, Brussels, Belgium
| | - Mohammed Bensellam
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain, Brussels, Belgium
| | - Heeyoung Chae
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain, Brussels, Belgium
| | - Manon Jaffredo
- CNRS, Institute of Chemistry and Biology of Membranes and Nano-objects, UMR 5248, University of Bordeaux, Pessac, France
| | - Anne-Françoise Close
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain, Brussels, Belgium
| | - Jean-Philippe Deglasse
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain, Brussels, Belgium
| | - Laila R B Santos
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain, Brussels, Belgium
- Bio Base Europe Pilot Plant (BBEPP), Ghent, Belgium
| | - Antoine Buemi
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle de chirurgie expérimentale, Université catholique de Louvain, Brussels, Belgium
| | - Nizar I Mourad
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle de chirurgie expérimentale, Université catholique de Louvain, Brussels, Belgium
| | - Anne Wojtusciszyn
- Laboratoire de Thérapie Cellulaire du Diabète, Institut de Médecine Régénérative et Biothérapies, Hôpital St Eloi, CHU Montpellier, Montpellier, France
- Service d'Endocrinologie, Diabétologie et Métabolisme, Centre Hospitalier Universitaire Vaudois and Université de Lausanne, Lausanne, Switzerland
| | - Matthieu Raoux
- CNRS, Institute of Chemistry and Biology of Membranes and Nano-objects, UMR 5248, University of Bordeaux, Pessac, France
| | - Patrick Gilon
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain, Brussels, Belgium
| | - Christophe Broca
- Laboratoire de Thérapie Cellulaire du Diabète, Institut de Médecine Régénérative et Biothérapies, Hôpital St Eloi, CHU Montpellier, Montpellier, France
| | - Jean-Christophe Jonas
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain, Brussels, Belgium.
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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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Čater M, Bombek LK. Protective Role of Mitochondrial Uncoupling Proteins against Age-Related Oxidative Stress in Type 2 Diabetes Mellitus. Antioxidants (Basel) 2022; 11:antiox11081473. [PMID: 36009191 PMCID: PMC9404801 DOI: 10.3390/antiox11081473] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 02/04/2023] Open
Abstract
The accumulation of oxidative damage to DNA and other biomolecules plays an important role in the etiology of aging and age-related diseases such as type 2 diabetes mellitus (T2D), atherosclerosis, and neurodegenerative disorders. Mitochondrial DNA (mtDNA) is especially sensitive to oxidative stress. Mitochondrial dysfunction resulting from the accumulation of mtDNA damage impairs normal cellular function and leads to a bioenergetic crisis that accelerates aging and associated diseases. Age-related mitochondrial dysfunction decreases ATP production, which directly affects insulin secretion by pancreatic beta cells and triggers the gradual development of the chronic metabolic dysfunction that characterizes T2D. At the same time, decreased glucose oxidation in skeletal muscle due to mitochondrial damage leads to prolonged postprandial blood glucose rise, which further worsens glucose homeostasis. ROS are not only highly reactive by-products of mitochondrial respiration capable of oxidizing DNA, proteins, and lipids but can also function as signaling and effector molecules in cell membranes mediating signal transduction and inflammation. Mitochondrial uncoupling proteins (UCPs) located in the inner mitochondrial membrane of various tissues can be activated by ROS to protect cells from mitochondrial damage. Mitochondrial UCPs facilitate the reflux of protons from the mitochondrial intermembrane space into the matrix, thereby dissipating the proton gradient required for oxidative phosphorylation. There are five known isoforms (UCP1-UCP5) of mitochondrial UCPs. UCP1 can indirectly reduce ROS formation by increasing glutathione levels, thermogenesis, and energy expenditure. In contrast, UCP2 and UCP3 regulate fatty acid metabolism and insulin secretion by beta cells and modulate insulin sensitivity. Understanding the functions of UCPs may play a critical role in developing pharmacological strategies to combat T2D. This review summarizes the current knowledge on the protective role of various UCP homologs against age-related oxidative stress in T2D.
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Affiliation(s)
- Maša Čater
- Correspondence: (M.Č.); (L.K.B.); Tel.: +386-2-2345-847 (L.K.B.)
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9
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Guérineau NC, Campos P, Le Tissier PR, Hodson DJ, Mollard P. Cell Networks in Endocrine/Neuroendocrine Gland Function. Compr Physiol 2022; 12:3371-3415. [PMID: 35578964 DOI: 10.1002/cphy.c210031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Reproduction, growth, stress, and metabolism are determined by endocrine/neuroendocrine systems that regulate circulating hormone concentrations. All these systems generate rhythms and changes in hormone pulsatility observed in a variety of pathophysiological states. Thus, the output of endocrine/neuroendocrine systems must be regulated within a narrow window of effective hormone concentrations but must also maintain a capacity for plasticity to respond to changing physiological demands. Remarkably most endocrinologists still have a "textbook" view of endocrine gland organization which has emanated from 20th century histological studies on thin 2D tissue sections. However, 21st -century technological advances, including in-depth 3D imaging of specific cell types have vastly changed our knowledge. We now know that various levels of multicellular organization can be found across different glands, that organizational motifs can vary between species and can be modified to enhance or decrease hormonal release. This article focuses on how the organization of cells regulates hormone output using three endocrine/neuroendocrine glands that present different levels of organization and complexity: the adrenal medulla, with a single neuroendocrine cell type; the anterior pituitary, with multiple intermingled cell types; and the pancreas with multiple intermingled cell types organized into distinct functional units. We give an overview of recent methodologies that allow the study of the different components within endocrine systems, particularly their temporal and spatial relationships. We believe the emerging findings about network organization, and its impact on hormone secretion, are crucial to understanding how homeostatic regulation of endocrine axes is carried out within endocrine organs themselves. © 2022 American Physiological Society. Compr Physiol 12:3371-3415, 2022.
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Affiliation(s)
| | - Pauline Campos
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Paul R Le Tissier
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, Scotland, UK
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Edgbaston, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK.,COMPARE University of Birmingham and University of Nottingham Midlands, UK.,Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Patrice Mollard
- IGF, University of Montpellier, CNRS, INSERM, Montpellier, France
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10
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Abarkan M, Pirog A, Mafilaza D, Pathak G, N'Kaoua G, Puginier E, O'Connor R, Raoux M, Donahue MJ, Renaud S, Lang J. Vertical Organic Electrochemical Transistors and Electronics for Low Amplitude Micro-Organ Signals. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2105211. [PMID: 35064774 PMCID: PMC8922095 DOI: 10.1002/advs.202105211] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Indexed: 06/14/2023]
Abstract
Electrical signals are fundamental to key biological events such as brain activity, heartbeat, or vital hormone secretion. Their capture and analysis provide insight into cell or organ physiology and a number of bioelectronic medical devices aim to improve signal acquisition. Organic electrochemical transistors (OECT) have proven their capacity to capture neuronal and cardiac signals with high fidelity and amplification. Vertical PEDOT:PSS-based OECTs (vOECTs) further enhance signal amplification and device density but have not been characterized in biological applications. An electronic board with individually tuneable transistor biases overcomes fabrication induced heterogeneity in device metrics and allows quantitative biological experiments. Careful exploration of vOECT electric parameters defines voltage biases compatible with reliable transistor function in biological experiments and provides useful maximal transconductance values without influencing cellular signal generation or propagation. This permits successful application in monitoring micro-organs of prime importance in diabetes, the endocrine pancreatic islets, which are known for their far smaller signal amplitudes as compared to neurons or heart cells. Moreover, vOECTs capture their single-cell action potentials and multicellular slow potentials reflecting micro-organ organizations as well as their modulation by the physiological stimulator glucose. This opens the possibility to use OECTs in new biomedical fields well beyond their classical applications.
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Affiliation(s)
- Myriam Abarkan
- UMR CNRS 5248 (CBMN, Chemistry and Biology of Membranes)Univ. BordeauxAv Geoffroy St HilairePessacF‐33600France
| | - Antoine Pirog
- UMR CNRS 5218 (IMS, Integration of Materials into Systems)Univ. BordeauxBordeaux Institut National Polytechnique351 Cours de la LibérationTalenceF‐33405France
| | - Donnie Mafilaza
- UMR CNRS 5218 (IMS, Integration of Materials into Systems)Univ. BordeauxBordeaux Institut National Polytechnique351 Cours de la LibérationTalenceF‐33405France
| | - Gaurav Pathak
- Department of BioelectronicsMines Saint EtienneCMP‐EMSEMOCGardanne13541France
- Linköping UniversityDepartment of Science and Technology (ITN)Laboratory of Organic ElectronicsLinköpingSE‐581 83Sweden
| | - Gilles N'Kaoua
- UMR CNRS 5218 (IMS, Integration of Materials into Systems)Univ. BordeauxBordeaux Institut National Polytechnique351 Cours de la LibérationTalenceF‐33405France
| | - Emilie Puginier
- UMR CNRS 5248 (CBMN, Chemistry and Biology of Membranes)Univ. BordeauxAv Geoffroy St HilairePessacF‐33600France
| | - Rodney O'Connor
- Department of BioelectronicsMines Saint EtienneCMP‐EMSEMOCGardanne13541France
| | - Matthieu Raoux
- UMR CNRS 5248 (CBMN, Chemistry and Biology of Membranes)Univ. BordeauxAv Geoffroy St HilairePessacF‐33600France
| | - Mary J. Donahue
- Department of BioelectronicsMines Saint EtienneCMP‐EMSEMOCGardanne13541France
- Linköping UniversityDepartment of Science and Technology (ITN)Laboratory of Organic ElectronicsLinköpingSE‐581 83Sweden
| | - Sylvie Renaud
- UMR CNRS 5218 (IMS, Integration of Materials into Systems)Univ. BordeauxBordeaux Institut National Polytechnique351 Cours de la LibérationTalenceF‐33405France
| | - Jochen Lang
- UMR CNRS 5248 (CBMN, Chemistry and Biology of Membranes)Univ. BordeauxAv Geoffroy St HilairePessacF‐33600France
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11
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Olçomendy L, Cassany L, Pirog A, Franco R, Puginier E, Jaffredo M, Gucik-Derigny D, Ríos H, Ferreira de Loza A, Gaitan J, Raoux M, Bornat Y, Catargi B, Lang J, Henry D, Renaud S, Cieslak J. Towards the Integration of an Islet-Based Biosensor in Closed-Loop Therapies for Patients With Type 1 Diabetes. Front Endocrinol (Lausanne) 2022; 13:795225. [PMID: 35528003 PMCID: PMC9072637 DOI: 10.3389/fendo.2022.795225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 02/25/2022] [Indexed: 01/01/2023] Open
Abstract
In diabetes mellitus (DM) treatment, Continuous Glucose Monitoring (CGM) linked with insulin delivery becomes the main strategy to improve therapeutic outcomes and quality of patients' lives. However, Blood Glucose (BG) regulation with CGM is still hampered by limitations of algorithms and glucose sensors. Regarding sensor technology, current electrochemical glucose sensors do not capture the full spectrum of other physiological signals, i.e., lipids, amino acids or hormones, relaying the general body status. Regarding algorithms, variability between and within patients remains the main challenge for optimal BG regulation in closed-loop therapies. This work highlights the simulation benefits to test new sensing and control paradigms which address the previous shortcomings for Type 1 Diabetes (T1D) closed-loop therapies. The UVA/Padova T1DM Simulator is the core element here, which is a computer model of the human metabolic system based on glucose-insulin dynamics in T1D patients. That simulator is approved by the US Food and Drug Administration (FDA) as an alternative for pre-clinical testing of new devices and closed-loop algorithms. To overcome the limitation of standard glucose sensors, the concept of an islet-based biosensor, which could integrate multiple physiological signals through electrical activity measurement, is assessed here in a closed-loop insulin therapy. This investigation has been addressed by an interdisciplinary consortium, from endocrinology to biology, electrophysiology, bio-electronics and control theory. In parallel to the development of an islet-based closed-loop, it also investigates the benefits of robust control theory against the natural variability within a patient population. Using 4 meal scenarios, numerous simulation campaigns were conducted. The analysis of their results then introduces a discussion on the potential benefits of an Artificial Pancreas (AP) system associating the islet-based biosensor with robust algorithms.
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Affiliation(s)
- Loïc Olçomendy
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
| | - Louis Cassany
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
| | - Antoine Pirog
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
| | - Roberto Franco
- Tecnológico Nacional de México/I.T. La Laguna, Torreón, Mexico
| | | | | | | | - Héctor Ríos
- Tecnológico Nacional de México/I.T. La Laguna, Torreón, Mexico
- Cátedras CONACYT, Ciudad de México, Mexico
| | | | - Julien Gaitan
- Univ. Bordeaux, CNRS, CBMN, UMR 5248, Pessac, France
| | | | - Yannick Bornat
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
| | - Bogdan Catargi
- Univ. Bordeaux, CNRS, CBMN, UMR 5248, Pessac, France
- Bordeaux Hospitals, Endocrinology and Metabolic Diseases Unit, Bordeaux, France
| | - Jochen Lang
- Univ. Bordeaux, CNRS, CBMN, UMR 5248, Pessac, France
| | - David Henry
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
| | - Sylvie Renaud
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
| | - Jérôme Cieslak
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
- *Correspondence: Jérôme Cieslak,
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12
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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
- *Correspondence: Marko Gosak,
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Kemter E, Müller A, Neukam M, Ivanova A, Klymiuk N, Renner S, Yang K, Broichhagen J, Kurome M, Zakhartchenko V, Kessler B, Knoch KP, Bickle M, Ludwig B, Johnsson K, Lickert H, Kurth T, Wolf E, Solimena M. Sequential in vivo labeling of insulin secretory granule pools in INS- SNAP transgenic pigs. Proc Natl Acad Sci U S A 2021; 118:e2107665118. [PMID: 34508004 PMCID: PMC8449372 DOI: 10.1073/pnas.2107665118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2021] [Indexed: 12/16/2022] Open
Abstract
β cells produce, store, and secrete insulin upon elevated blood glucose levels. Insulin secretion is a highly regulated process. The probability for insulin secretory granules to undergo fusion with the plasma membrane or being degraded is correlated with their age. However, the molecular features and stimuli connected to this behavior have not yet been fully understood. Furthermore, our understanding of β cell function is mostly derived from studies of ex vivo isolated islets in rodent models. To overcome this translational gap and study insulin secretory granule turnover in vivo, we have generated a transgenic pig model with the SNAP-tag fused to insulin. We demonstrate the correct targeting and processing of the tagged insulin and normal glycemic control of the pig model. Furthermore, we show specific single- and dual-color granular labeling of in vivo-labeled pig pancreas. This model may provide unprecedented insights into the in vivo insulin secretory granule behavior in an animal close to humans.
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Affiliation(s)
- Elisabeth Kemter
- Chair for Molecular Animal Breeding and Biotechnology Gene Center, Ludwig Maximilian University of Munich, 81377 Munich, Germany
- Center for Innovative Medical Models, Ludwig Maximilian University of Munich, 81377 Munich, Germany
- German Center for Diabetes Research, 85764 Neuherberg, Germany
| | - Andreas Müller
- German Center for Diabetes Research, 85764 Neuherberg, Germany
- Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich, University Hospital Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Martin Neukam
- German Center for Diabetes Research, 85764 Neuherberg, Germany
- Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich, University Hospital Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Anna Ivanova
- German Center for Diabetes Research, 85764 Neuherberg, Germany
- Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich, University Hospital Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Nikolai Klymiuk
- Chair for Molecular Animal Breeding and Biotechnology Gene Center, Ludwig Maximilian University of Munich, 81377 Munich, Germany
- Center for Innovative Medical Models, Ludwig Maximilian University of Munich, 81377 Munich, Germany
| | - Simone Renner
- Chair for Molecular Animal Breeding and Biotechnology Gene Center, Ludwig Maximilian University of Munich, 81377 Munich, Germany
- Center for Innovative Medical Models, Ludwig Maximilian University of Munich, 81377 Munich, Germany
- German Center for Diabetes Research, 85764 Neuherberg, Germany
| | - Kaiyuan Yang
- German Center for Diabetes Research, 85764 Neuherberg, Germany
- Institute of Diabetes and Regeneration Research, Helmholtz Diabetes Center, Helmholtz Center Munich, 85764 Neuherberg, Germany
| | - Johannes Broichhagen
- Department of Chemical Biology, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
- Chemical Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Mayuko Kurome
- Chair for Molecular Animal Breeding and Biotechnology Gene Center, Ludwig Maximilian University of Munich, 81377 Munich, Germany
- Center for Innovative Medical Models, Ludwig Maximilian University of Munich, 81377 Munich, Germany
| | - Valeri Zakhartchenko
- Chair for Molecular Animal Breeding and Biotechnology Gene Center, Ludwig Maximilian University of Munich, 81377 Munich, Germany
- Center for Innovative Medical Models, Ludwig Maximilian University of Munich, 81377 Munich, Germany
| | - Barbara Kessler
- Chair for Molecular Animal Breeding and Biotechnology Gene Center, Ludwig Maximilian University of Munich, 81377 Munich, Germany
- Center for Innovative Medical Models, Ludwig Maximilian University of Munich, 81377 Munich, Germany
| | - Klaus-Peter Knoch
- German Center for Diabetes Research, 85764 Neuherberg, Germany
- Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich, University Hospital Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Marc Bickle
- Technology Development Studio (TDS), Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Barbara Ludwig
- German Center for Diabetes Research, 85764 Neuherberg, Germany
- Department of Medicine III, University Hospital Carl Gustav Carus, 01307 Dresden, Germany
| | - Kai Johnsson
- Department of Chemical Biology, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Heiko Lickert
- German Center for Diabetes Research, 85764 Neuherberg, Germany
- Institute of Diabetes and Regeneration Research, Helmholtz Diabetes Center, Helmholtz Center Munich, 85764 Neuherberg, Germany
| | - Thomas Kurth
- Center for Molecular and Cellular Bioengineering Technology Platform, Technische Universität Dresden, 01307 Dresden, Germany
| | - Eckhard Wolf
- Chair for Molecular Animal Breeding and Biotechnology Gene Center, Ludwig Maximilian University of Munich, 81377 Munich, Germany;
- Center for Innovative Medical Models, Ludwig Maximilian University of Munich, 81377 Munich, Germany
- German Center for Diabetes Research, 85764 Neuherberg, Germany
| | - Michele Solimena
- German Center for Diabetes Research, 85764 Neuherberg, Germany;
- Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich, University Hospital Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
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Fischer KL, Jaffredo M, Lang J, Raoux M. [Pancreatic α and β cells: Best enemies or partners for life?]. Med Sci (Paris) 2021; 37:752-758. [PMID: 34491183 DOI: 10.1051/medsci/2021111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Diabetes are major metabolic diseases constantly increasing in the population, caused by reduced secretion and action of insulin, the only hormone lowering efficiently the glycaemia. Insulin is secreted by β cells within the pancreatic islets of Langerhans. The islet micro-organs also contain 15 to 35% of α cells, well-known for their opposite effects on glycaemia. Considered until now as potentially harmful in diabetes, α cells are emerging as potent enhancers of β cell activity when studied in physiological nutritional setting and should therefore be reconsidered in a therapeutic point of view. This review summarizes the latest concepts regarding β cell function in physiological states and the involvement of dynamic functional interactions between α and β cells for the regulation of nutrient homeostasis.
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Affiliation(s)
- Karen Leal Fischer
- Institut de chimie et de biologie des membranes et des nano-objets, CBMN, Université de Bordeaux, CNRS UMR 5248, B14 allée Geoffroy Saint Hilaire, F-33600, Pessac, France
| | - Manon Jaffredo
- Institut de chimie et de biologie des membranes et des nano-objets, CBMN, Université de Bordeaux, CNRS UMR 5248, B14 allée Geoffroy Saint Hilaire, F-33600, Pessac, France
| | - Jochen Lang
- Institut de chimie et de biologie des membranes et des nano-objets, CBMN, Université de Bordeaux, CNRS UMR 5248, B14 allée Geoffroy Saint Hilaire, F-33600, Pessac, France
| | - Matthieu Raoux
- Institut de chimie et de biologie des membranes et des nano-objets, CBMN, Université de Bordeaux, CNRS UMR 5248, B14 allée Geoffroy Saint Hilaire, F-33600, Pessac, France
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15
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Olcomendy L, Pirog A, Lebreton F, Jaffredo M, Cassany L, Gucik Derigny D, Cieslak J, Henry D, Lang J, Catargi B, Raoux M, Bornat Y, Renaud S. Integrating an Islet-Based Biosensor in the Artificial Pancreas: In Silico Proof-of-Concept. IEEE Trans Biomed Eng 2021; 69:899-909. [PMID: 34469288 DOI: 10.1109/tbme.2021.3109096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Current treatment of type 1 diabetes by closed-loop approaches depends on continuous glucose monitoring. However, glucose readings alone are insufficient for an artificial pancreas to truthfully restore glucose homeostasis where additional physiological regulators of insulin secretion play a considerable role. Previously, we have developed an electrophysiological biosensor of pancreatic islet activity, which integrates these additional regulators through electrical measurement. This work aims at investigating the performance of the biosensor in a blood glucose control loop, to establish an in silico proof-of-concept. METHODS Two islet algorithm models were identified on experimental data recorded with the biosensor. First, we validated electrical measurement as a means to exploit the inner regulation capabilities of islets for intravenous glucose measurement and insulin infusion. Then, an artificial pancreas integrating the islet-based biosensor was compared to standard treatment approaches using subcutaneous routes. The closed-loop simulations were performed in the UVA/Padova T1DM Simulator where a series of realistic meal scenarios were applied to virtual diabetic patients. RESULTS With intravenous routes, the endogenous islet algorithms successfully restored glucose homeostasis for all patient categories (mean time in range exceeds 90%) while mitigating the risk of adverse glycaemic events (mean BGI < 2). Using subcutaneous routes, the biosensor-based artificial pancreas was as performing as standard treatments, and outperformed them under challenging conditions. CONCLUSION This work validates the concept of using pancreatic islets algorithms in an artificial pancreas in silico. SIGNIFICANCE Pancreatic islet endogenous algorithms obtained via an electrophysiological biosensor successfully regulate blood glucose levels of virtual type 1 diabetic patients.
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16
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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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Zmazek J, Klemen MS, Markovič R, Dolenšek J, Marhl M, Stožer A, Gosak M. Assessing Different Temporal Scales of Calcium Dynamics in Networks of Beta Cell Populations. Front Physiol 2021; 12:612233. [PMID: 33833686 PMCID: PMC8021717 DOI: 10.3389/fphys.2021.612233] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/26/2021] [Indexed: 01/06/2023] Open
Abstract
Beta cells within the pancreatic islets of Langerhans respond to stimulation with coherent oscillations of membrane potential and intracellular calcium concentration that presumably drive the pulsatile exocytosis of insulin. Their rhythmic activity is multimodal, resulting from networked feedback interactions of various oscillatory subsystems, such as the glycolytic, mitochondrial, and electrical/calcium components. How these oscillatory modules interact and affect the collective cellular activity, which is a prerequisite for proper hormone release, is incompletely understood. In the present work, we combined advanced confocal Ca2+ imaging in fresh mouse pancreas tissue slices with time series analysis and network science approaches to unveil the glucose-dependent characteristics of different oscillatory components on both the intra- and inter-cellular level. Our results reveal an interrelationship between the metabolically driven low-frequency component and the electrically driven high-frequency component, with the latter exhibiting the highest bursting rates around the peaks of the slow component and the lowest around the nadirs. Moreover, the activity, as well as the average synchronicity of the fast component, considerably increased with increasing stimulatory glucose concentration, whereas the stimulation level did not affect any of these parameters in the slow component domain. Remarkably, in both dynamical components, the average correlation decreased similarly with intercellular distance, which implies that intercellular communication affects the synchronicity of both types of oscillations. To explore the intra-islet synchronization patterns in more detail, we constructed functional connectivity maps. The subsequent comparison of network characteristics of different oscillatory components showed more locally clustered and segregated networks of fast oscillatory activity, while the slow oscillations were more global, resulting in several long-range connections and a more cohesive structure. Besides the structural differences, we found a relatively weak relationship between the fast and slow network layer, which suggests that different synchronization mechanisms shape the collective cellular activity in islets, a finding which has to be kept in mind in future studies employing different oscillations for constructing networks.
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Affiliation(s)
- Jan Zmazek
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
| | | | - Rene Markovič
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Electrical Engineering and Computer Science, 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
| | - Marko Marhl
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Medicine, 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 Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
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