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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 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] [What about the content of this article? (0)] [Affiliation(s)] [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] [What about the content of this article? (0)] [Affiliation(s)] [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] [What about the content of this article? (0)] [Affiliation(s)] [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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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. Adv Sci (Weinh) 2022; 9:e2105211. [PMID: 35064774 PMCID: PMC8922095 DOI: 10.1002/advs.202105211] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [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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Jaffredo M, Bertin E, Pirog A, Puginier E, Gaitan J, Oucherif S, Lebreton F, Bosco D, Catargi B, Cattaert D, Renaud S, Lang J, Raoux M. Dynamic Uni- and Multicellular Patterns Encode Biphasic Activity in Pancreatic Islets. Diabetes 2021; 70:878-888. [PMID: 33468514 DOI: 10.2337/db20-0214] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 01/11/2021] [Indexed: 11/13/2022]
Abstract
Biphasic secretion is an autonomous feature of many endocrine micro-organs to fulfill physiological demands. The biphasic activity of islet β-cells maintains glucose homeostasis and is altered in type 2 diabetes. Nevertheless, underlying cellular or multicellular functional organizations are only partially understood. High-resolution noninvasive multielectrode array recordings permit simultaneous analysis of recruitment, of single-cell, and of coupling activity within entire islets in long-time experiments. Using this unbiased approach, we addressed the organizational modes of both first and second phase in mouse and human islets under physiological and pathophysiological conditions. Our data provide a new uni- and multicellular model of islet β-cell activation: during the first phase, small but highly active β-cell clusters are dominant, whereas during the second phase, electrical coupling generates large functional clusters via multicellular slow potentials to favor an economic sustained activity. Postprandial levels of glucagon-like peptide 1 favor coupling only in the second phase, whereas aging and glucotoxicity alter coupled activity in both phases. In summary, biphasic activity is encoded upstream of vesicle pools at the micro-organ level by multicellular electrical signals and their dynamic synchronization between β-cells. The profound alteration of the electrical organization of islets in pathophysiological conditions may contribute to functional deficits in type 2 diabetes.
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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
| | - Eléonore Bertin
- University of Bordeaux, CNRS, Institute of Chemistry and Biology of Membranes and Nano-objects, UMR 5248, Pessac, France
| | - Antoine Pirog
- University of Bordeaux, CNRS, Institut National Polytechnique de Bordeaux, Laboratoire de l'Intégration du Matériau au Système, UMR 5218, Talence, France
| | - Emilie Puginier
- University of Bordeaux, CNRS, Institute of Chemistry and Biology of Membranes and Nano-objects, UMR 5248, Pessac, France
| | - Julien Gaitan
- University of Bordeaux, CNRS, Institute of Chemistry and Biology of Membranes and Nano-objects, UMR 5248, Pessac, France
| | - Sandra Oucherif
- University of Bordeaux, CNRS, Institute of Chemistry and Biology of Membranes and Nano-objects, UMR 5248, Pessac, France
| | - Fanny Lebreton
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals, University of Geneva, Geneva, Switzerland
| | - Domenico Bosco
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals, University of Geneva, Geneva, Switzerland
| | - Bogdan Catargi
- University of Bordeaux, CNRS, Institute of Chemistry and Biology of Membranes and Nano-objects, UMR 5248, Pessac, France
- University of Bordeaux, Hôpital Saint-André, Endocrinology and Metabolic Diseases, Bordeaux, France
| | - Daniel Cattaert
- University of Bordeaux, CNRS, Aquitaine Institute for Cognitive and Integrative Neuroscience, UMR 5287, Bordeaux, France
| | - Sylvie Renaud
- University of Bordeaux, CNRS, Institut National Polytechnique de Bordeaux, Laboratoire de l'Intégration du Matériau au Système, UMR 5218, Talence, France
| | - Jochen Lang
- University of Bordeaux, CNRS, Institute of Chemistry and Biology of Membranes and Nano-objects, UMR 5248, Pessac, France
| | - Matthieu Raoux
- University of Bordeaux, CNRS, Institute of Chemistry and Biology of Membranes and Nano-objects, UMR 5248, Pessac, France
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Salinas G, Villarroel Marquez A, Idir M, Shinde S, Frontana‐Uribe BA, Raoux M, Lang J, Cloutet E, Kuhn A. Sodium‐Ion Selectivity Study of a Crown‐Ether‐Functionalized PEDOT Analog. ChemElectroChem 2020. [DOI: 10.1002/celc.202000693] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Gerardo Salinas
- Univ. Bordeaux ISM, CNRS UMR 5255 Bordeaux INP, F 33607 Pessac France
| | - Ariana Villarroel Marquez
- Univ. Bordeaux LCPO, CNRS UMR 5629 Bordeaux INP F-33615 Pessac France
- Univ. Bordeaux CBMN, CNRS UMR 5248 Bordeaux INP F-33600 Pessac France
| | - Maël Idir
- Univ. Bordeaux LCPO, CNRS UMR 5629 Bordeaux INP F-33615 Pessac France
| | - Shekhar Shinde
- Univ. Bordeaux LCPO, CNRS UMR 5629 Bordeaux INP F-33615 Pessac France
| | - Bernardo A. Frontana‐Uribe
- Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM Km 14.5 Carretera Toluca-Atlacomulco 50200 Toluca México
- Instituto de Química, UNAM Circuito Exterior Ciudad Universitaria 04510 CDMX, México
| | - Matthieu Raoux
- Univ. Bordeaux CBMN, CNRS UMR 5248 Bordeaux INP F-33600 Pessac France
| | - Jochen Lang
- Univ. Bordeaux CBMN, CNRS UMR 5248 Bordeaux INP F-33600 Pessac France
| | - Eric Cloutet
- Univ. Bordeaux LCPO, CNRS UMR 5629 Bordeaux INP F-33615 Pessac France
| | - Alexander Kuhn
- Univ. Bordeaux ISM, CNRS UMR 5255 Bordeaux INP, F 33607 Pessac France
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Villarroel Marquez A, Salinas G, Abarkan M, Idir M, Brochon C, Hadziioannou G, Raoux M, Kuhn A, Lang J, Cloutet E. Design of Potassium‐Selective Mixed Ion/Electron Conducting Polymers. Macromol Rapid Commun 2020. [DOI: 10.1002/marc.202070030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Villarroel Marquez A, Salinas G, Abarkan M, Idir M, Brochon C, Hadziioannou G, Raoux M, Kuhn A, Lang J, Cloutet E. Design of Potassium‐Selective Mixed Ion/Electron Conducting Polymers. Macromol Rapid Commun 2020; 41:e2000134. [DOI: 10.1002/marc.202000134] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/07/2020] [Accepted: 04/20/2020] [Indexed: 12/22/2022]
Affiliation(s)
- Ariana Villarroel Marquez
- University of BordeauxCNRS, Bordeaux INP LCPO, UMR 5629 Pessac F‐33615 France
- Prof. J. LangUniversity of BordeauxCNRS, Bordeaux INP CBMN, UMR 5248 Pessac F‐33600 France
| | - Gerardo Salinas
- University of BordeauxCNRS, Bordeaux INP ISM, UMR 5255 Pessac F‐33607 France
| | - Myriam Abarkan
- Prof. J. LangUniversity of BordeauxCNRS, Bordeaux INP CBMN, UMR 5248 Pessac F‐33600 France
| | - Maël Idir
- University of BordeauxCNRS, Bordeaux INP LCPO, UMR 5629 Pessac F‐33615 France
| | - Cyril Brochon
- University of BordeauxCNRS, Bordeaux INP LCPO, UMR 5629 Pessac F‐33615 France
| | | | - Matthieu Raoux
- Prof. J. LangUniversity of BordeauxCNRS, Bordeaux INP CBMN, UMR 5248 Pessac F‐33600 France
| | - Alexander Kuhn
- University of BordeauxCNRS, Bordeaux INP ISM, UMR 5255 Pessac F‐33607 France
| | - Jochen Lang
- Prof. J. LangUniversity of BordeauxCNRS, Bordeaux INP CBMN, UMR 5248 Pessac F‐33600 France
| | - Eric Cloutet
- University of BordeauxCNRS, Bordeaux INP LCPO, UMR 5629 Pessac F‐33615 France
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12
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Abarkan M, Gaitan J, Lebreton F, Perrier R, Jaffredo M, Mulle C, Magnan C, Raoux M, Lang J. The glutamate receptor GluK2 contributes to the regulation of glucose homeostasis and its deterioration during aging. Mol Metab 2019; 30:152-160. [PMID: 31767166 PMCID: PMC6807305 DOI: 10.1016/j.molmet.2019.09.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/04/2019] [Accepted: 09/27/2019] [Indexed: 01/23/2023] Open
Abstract
OBJECTIVE Islets secrete neurotransmitters including glutamate which participate in fine regulation of islet function. The excitatory ionotropic glutamate receptor GluK2 of the kainate receptor family is widely expressed in brain and also found in islets, mainly in α and γ cells. α cells co-release glucagon and glutamate and the latter increases glucagon release via ionotropic glutamate receptors. However, neither the precise nature of the ionotropic glutamate receptor involved nor its role in glucose homeostasis is known. As isoform specific pharmacology is not available, we investigated this question in constitutive GluK2 knock-out mice (GluK2-/-) using adult and middle-aged animals to also gain insight in a potential role during aging. METHODS We compared wild-type GluK2+/+ and knock-out GluK2-/- mice using adult (14-20 weeks) and middle-aged animals (40-52 weeks). Glucose (oral OGTT and intraperitoneal IPGTT) and insulin tolerance as well as pyruvate challenge tests were performed according to standard procedures. Parasympathetic activity, which stimulates hormones secretion, was measured by electrophysiology in vivo. Isolated islets were used in vitro to determine islet β-cell electrical activity on multi-electrode arrays and dynamic secretion of insulin as well as glucagon was determined by ELISA. RESULTS Adult GluK2-/- mice exhibit an improved glucose tolerance (OGTT and IPGTT), and this was also apparent in middle-aged mice, whereas the outcome of pyruvate challenge was slightly improved only in middle-aged GluK2-/- mice. Similarly, insulin sensitivity was markedly enhanced in middle-aged GluK2-/- animals. Basal and glucose-induced insulin secretion in vivo was slightly lower in GluK2-/- mice, whereas fasting glucagonemia was strongly reduced. In vivo recordings of parasympathetic activity showed an increase in basal activity in GluK2-/- mice which represents most likely an adaptive mechanism to counteract hypoglucagonemia rather than altered neuronal mechanism. In vitro recording demonstrated an improvement of glucose-induced electrical activity of β-cells in islets obtained from GluK2-/- mice at both ages. Finally, glucose-induced insulin secretion in vitro was increased in GluK2-/- islets, whereas glucagon secretion at 2 mmol/l of glucose was considerably reduced. CONCLUSIONS These observations indicate a general role for kainate receptors in glucose homeostasis and specifically suggest a negative effect of GluK2 on glucose homeostasis and preservation of islet function during aging. Our observations raise the possibility that blockade of GluK2 may provide benefits in glucose homeostasis especially during aging.
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Affiliation(s)
- Myriam Abarkan
- Chimie et Biologie des Membranes et Nano-objets, UMR CNRS 5248, Université de Bordeaux, Pessac, France
| | - Julien Gaitan
- Chimie et Biologie des Membranes et Nano-objets, UMR CNRS 5248, Université de Bordeaux, Pessac, France
| | - Fanny Lebreton
- Chimie et Biologie des Membranes et Nano-objets, UMR CNRS 5248, Université de Bordeaux, Pessac, France
| | - Romain Perrier
- Chimie et Biologie des Membranes et Nano-objets, UMR CNRS 5248, Université de Bordeaux, Pessac, France
| | - Manon Jaffredo
- Chimie et Biologie des Membranes et Nano-objets, UMR CNRS 5248, Université de Bordeaux, Pessac, France
| | - Christophe Mulle
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Université de Bordeaux, Bordeaux, France
| | - Christophe Magnan
- Unité de Biologie Fonctionnelle et Adaptative, UMR 8251, CNRS, Université de Paris, Paris, France
| | - Matthieu Raoux
- Chimie et Biologie des Membranes et Nano-objets, UMR CNRS 5248, Université de Bordeaux, Pessac, France
| | - Jochen Lang
- Chimie et Biologie des Membranes et Nano-objets, UMR CNRS 5248, Université de Bordeaux, Pessac, France.
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Pirog A, Bornat Y, Perrier R, Raoux M, Jaffredo M, Quotb A, Lang J, Lewis N, Renaud S. Multimed: An Integrated, Multi-Application Platform for the Real-Time Recording and Sub-Millisecond Processing of Biosignals. Sensors (Basel) 2018; 18:E2099. [PMID: 29966339 PMCID: PMC6069272 DOI: 10.3390/s18072099] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 06/23/2018] [Accepted: 06/27/2018] [Indexed: 12/30/2022]
Abstract
Enhanced understanding and control of electrophysiology mechanisms are increasingly being hailed as key knowledge in the fields of modern biology and medicine. As more and more excitable cell mechanics are being investigated and exploited, the need for flexible electrophysiology setups becomes apparent. With that aim, we designed Multimed, which is a versatile hardware platform for the real-time recording and processing of biosignals. Digital processing in Multimed is an arrangement of generic processing units from a custom library. These can freely be rearranged to match the needs of the application. Embedded onto a Field Programmable Gate Array (FPGA), these modules utilize full-hardware signal processing to lower processing latency. It achieves constant latency, and sub-millisecond processing and decision-making on 64 channels. The FPGA core processing unit makes Multimed suitable as either a reconfigurable electrophysiology system or a prototyping platform for VLSI implantable medical devices. It is specifically designed for open- and closed-loop experiments and provides consistent feedback rules, well within biological microseconds timeframes. This paper presents the specifications and architecture of the Multimed system, then details the biosignal processing algorithms and their digital implementation. Finally, three applications utilizing Multimed in neuroscience and diabetes research are described. They demonstrate the system’s configurability, its multi-channel, real-time processing, and its feedback control capabilities.
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Affiliation(s)
- Antoine Pirog
- Laboratoire de l'Intégration du Matériau au Système (IMS), University of Bordeaux, Bordeaux INP, CNRS UMR 5218, F-33400 Talence, France.
| | - Yannick Bornat
- Laboratoire de l'Intégration du Matériau au Système (IMS), University of Bordeaux, Bordeaux INP, CNRS UMR 5218, F-33400 Talence, France.
| | - Romain Perrier
- Signalisation et physiopathologie cardiovasculaire, INSERM S-1180, University of Paris Sud, F-92296 Châtenay-Malabry, France.
| | - Matthieu Raoux
- Institut de Chimie et Biologie des Membranes et des Nano-objets (CBMN), University of Bordeaux, CNRS UMR 5248, F-33600 Pessac, France.
| | - Manon Jaffredo
- Institut de Chimie et Biologie des Membranes et des Nano-objets (CBMN), University of Bordeaux, CNRS UMR 5248, F-33600 Pessac, France.
| | - Adam Quotb
- Laboratoire d'Analyse et d'Architecture des Systèmes (LAAS), Federal University of Toulouse Midi-Pyrénées, CNRS UMR 8001, F-31031 Toulouse, France.
| | - Jochen Lang
- Institut de Chimie et Biologie des Membranes et des Nano-objets (CBMN), University of Bordeaux, CNRS UMR 5248, F-33600 Pessac, France.
| | - Noëlle Lewis
- Laboratoire de l'Intégration du Matériau au Système (IMS), University of Bordeaux, Bordeaux INP, CNRS UMR 5218, F-33400 Talence, France.
| | - Sylvie Renaud
- Laboratoire de l'Intégration du Matériau au Système (IMS), University of Bordeaux, Bordeaux INP, CNRS UMR 5218, F-33400 Talence, France.
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14
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Perrier R, Pirog A, Jaffredo M, Gaitan J, Catargi B, Renaud S, Raoux M, Lang J. Bioelectronic organ-based sensor for microfluidic real-time analysis of the demand in insulin. Biosens Bioelectron 2018; 117:253-259. [PMID: 29909196 DOI: 10.1016/j.bios.2018.06.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 06/04/2018] [Accepted: 06/06/2018] [Indexed: 12/31/2022]
Abstract
On-line and real-time analysis of micro-organ activity permits to use the endogenous analytical power of cellular signal transduction algorithms as biosensors. We have developed here such a sensor using only a few pancreatic endocrine islets and the avoidance of transgenes or chemical probes reduces bias and procures general usage. Nutrient and hormone-induced changes in islet ion fluxes through channels provide the first integrative read-out of micro-organ activity. Using extracellular electrodes we captured this read-out non-invasively as slow potentials which reflect glucose concentration-dependent (3-15 mM) micro-organ activation and coupling. Custom-made PDMS-based microfluidics with platinum black micro-electrode arrays required only some tens of islets and functioned at flow rates of 1-10 µl/min which are compatible with microdialysis. We developed hardware solutions for on-line real-time analysis on a reconfigurable Field-Programmable Gate Array (FPGA) that offered resource-efficient architecture and storage of intermediary processing stages. Moreover, real-time adaptive and reconfigurable algorithms accounted for signal disparities and noise distribution. Based on islet slow potentials, this integrated set-up allowed within less than 40 μs the discrimination and precise automatic ranking of small increases (2 mM steps) of glucose concentrations in real time and within the physiological glucose range. This approach shall permit further development in continuous monitoring of the demand for insulin in type 1 diabetes as well as monitoring of organs-on-chip or maturation of stem-cell derived islets.
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Affiliation(s)
- R Perrier
- Laboratoire de Chimie et Biologie des Membranes et des Nano-Objets (CBMN), UMR CNRS 5248, Univ. Bordeaux, 18 Av Geoffroy St Hilaire, 33600 Pessac, France
| | - A Pirog
- Laboratoire d'Intégration du Matériau au Système (IMS), UMR CNRS 5218, Univ. Bordeaux, Bordeaux INP, 33400 Talence, France
| | - M Jaffredo
- Laboratoire de Chimie et Biologie des Membranes et des Nano-Objets (CBMN), UMR CNRS 5248, Univ. Bordeaux, 18 Av Geoffroy St Hilaire, 33600 Pessac, France
| | - J Gaitan
- Laboratoire de Chimie et Biologie des Membranes et des Nano-Objets (CBMN), UMR CNRS 5248, Univ. Bordeaux, 18 Av Geoffroy St Hilaire, 33600 Pessac, France
| | - B Catargi
- Laboratoire de Chimie et Biologie des Membranes et des Nano-Objets (CBMN), UMR CNRS 5248, Univ. Bordeaux, 18 Av Geoffroy St Hilaire, 33600 Pessac, France; Hôpital St André, Bordeaux University Hospital, Univ. Bordeaux, 1 rue Jean Burguet, 33000 Bordeaux, France
| | - S Renaud
- Laboratoire d'Intégration du Matériau au Système (IMS), UMR CNRS 5218, Univ. Bordeaux, Bordeaux INP, 33400 Talence, France
| | - M Raoux
- Laboratoire de Chimie et Biologie des Membranes et des Nano-Objets (CBMN), UMR CNRS 5248, Univ. Bordeaux, 18 Av Geoffroy St Hilaire, 33600 Pessac, France
| | - J Lang
- Laboratoire de Chimie et Biologie des Membranes et des Nano-Objets (CBMN), UMR CNRS 5248, Univ. Bordeaux, 18 Av Geoffroy St Hilaire, 33600 Pessac, France.
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Abstract
Control of transport across membranes, whether natural or synthetic, is fundamental in many biotechnology applications, including sensing and drug release. Mutations of naturally existing protein channels, such as hemolysin, have been explored in the past. More recently, DNA channels with conductivities in the nanosiemens range have been designed. Regulating transport across DNA channels in response to external stimuli remains an important challenge. Previous designs relied on steric hindrance to control the inner diameter of the channel, which resulted in unstable electric signatures. In this paper we introduce a new design to control electric channel conductance of a DNA nanopore. The tensegrity driven mechanism inhibits the flux of small analytes while keeping a tightly controlled ionic transport modulated by the addition of specific DNA sequences. Current signals are clearly defined, with no sign of gating, opening new perspectives in single molecule DNA sensing.
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Affiliation(s)
- O Mendoza
- CBMN, UMR5248, 33600 Pessac, France.
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16
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Pedraza E, Karajić A, Raoux M, Perrier R, Pirog A, Lebreton F, Arbault S, Gaitan J, Renaud S, Kuhn A, Lang J. Guiding pancreatic beta cells to target electrodes in a whole-cell biosensor for diabetes. Lab Chip 2015; 15:3880-3890. [PMID: 26282013 DOI: 10.1039/c5lc00616c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We are developing a cell-based bioelectronic glucose sensor that exploits the multi-parametric sensing ability of pancreatic islet cells for the treatment of diabetes. These cells sense changes in the concentration of glucose and physiological hormones and immediately react by generating electrical signals. In our sensor, signals from multiple cells are recorded as field potentials by a micro-electrode array (MEA). Thus, cell response to various factors can be assessed rapidly and with high throughput. However, signal quality and consequently overall sensor performance rely critically on close cell-electrode proximity. Therefore, we present here a non-invasive method of further exploiting the electrical properties of these cells to guide them towards multiple micro-electrodes via electrophoresis. Parameters were optimized by measuring the cell's zeta potential and modeling the electric field distribution. Clonal and primary mouse or human β-cells migrated directly to target electrodes during the application of a 1 V potential between MEA electrodes for 3 minutes. The morphology, insulin secretion, and electrophysiological characteristics were not altered compared to controls. Thus, cell manipulation on standard MEAs was achieved without introducing any external components and while maintaining the performance of the biosensor. Since the analysis of the cells' electrical activity was performed in real time via on-chip recording and processing, this work demonstrates that our biosensor is operational from the first step of electrically guiding cells to the final step of automatic recognition. Our favorable results with pancreatic islets, which are highly sensitive and fragile cells, are encouraging for the extension of this technique to other cell types and microarray devices.
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Affiliation(s)
- Eileen Pedraza
- CNRS UMR 5248, Chimie et Biologie des Membranes et Nano-objets, Allée Geoffroy Saint-Hilaire, Pessac, France
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Lebreton F, Pirog A, Belouah I, Bosco D, Berney T, Meda P, Bornat Y, Catargi B, Renaud S, Raoux M, Lang J. Slow potentials encode intercellular coupling and insulin demand in pancreatic beta cells. Diabetologia 2015; 58:1291-9. [PMID: 25788295 DOI: 10.1007/s00125-015-3558-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 02/23/2015] [Indexed: 11/24/2022]
Abstract
AIMS/HYPOTHESIS Ion fluxes constitute a major integrative signal in beta cells that leads to insulin secretion and regulation of gene expression. Understanding these electrical signals is important for deciphering the endogenous algorithms used by islets to attain homeostasis and for the design of new sensors for monitoring beta cell function. METHODS Mouse and human islets were cultured on multielectrode arrays (MEAs) for 3-13 days. Extracellular electrical activities received on each electrode were continuously amplified and recorded for offline characterisation. RESULTS Differential band-pass filtering of MEA recordings of mouse islets showed two extracellular voltage waveforms: action potentials (lasting 40-60 ms) and very robust slow potentials (SPs, lasting 800-1,500 ms), the latter of which have not been described previously. The frequency of SPs directly correlated with glucose concentration, peaked at 10 mmol/l glucose and was further augmented by picomolar concentrations of glucagon-like peptide-1. SPs required the closure of ATP-dependent potassium channels as they were induced by glucose or glibenclamide but were not elicited by KCl-induced depolarisation. Pharmacological tools and the use of beta cell specific knockout mice showed that SPs reflected cell coupling via connexin 36. Moreover, increasing and decreasing glucose ramps showed hysteresis with reduced glucose sensitivity during the decreasing phase. SPs were also observed in human islets and could be continuously recorded over 24 h. CONCLUSIONS/INTERPRETATION This novel electrical signature reflects the syncytial function of the islets and is specific to beta cells. Moreover, the observed hysteresis provides evidence for an endogenous algorithm naturally present in islets to protect against hypoglycaemia.
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Affiliation(s)
- Fanny Lebreton
- CNRS UMR 5248, Chimie et Biologie des Membranes et Nano-objets, Université de Bordeaux, Batiment B14, Allée Geoffroy St Hilaire, CS90063, 33615, Pessac, France
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18
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Raoux M, Vacher P, Papin J, Picard A, Kostrzewa E, Devin A, Gaitan J, Limon I, Kas MJ, Magnan C, Lang J. Multilevel control of glucose homeostasis by adenylyl cyclase 8. Diabetologia 2015; 58:749-57. [PMID: 25403481 DOI: 10.1007/s00125-014-3445-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 10/28/2014] [Indexed: 01/22/2023]
Abstract
AIMS/HYPOTHESIS Nutrient homeostasis requires integration of signals generated by glucose metabolism and hormones. Expression of the calcium-stimulated adenylyl cyclase ADCY8 is regulated by glucose and the enzyme is capable of integrating signals from multiple pathways. It may thus have an important role in glucose-induced signalling and glucose homeostasis. METHODS We used pharmacological and genetic approaches in beta cells to determine secretion and calcium metabolism. Furthermore, Adcy8 knockout mice were characterised. RESULTS In clonal beta cells, inhibitors of adenylyl cyclases or their downstream targets reduced the glucose-induced increase in cytosolic calcium and insulin secretion. This was reproduced by knock-down of ADCY8, but not of ADCY1. These agents also inhibited glucose-induced increase in cytosolic calcium and electrical activity in primary beta cells and similar effects were observed after ADCY8 knock-down. Moreover, insulin secretion was diminished in islets from Adcy8 knockout mice. These mice were glucose intolerant after oral or intraperitoneal administration of glucose whereas their levels of glucagon-like peptide-1 remained unaltered. Finally, we knocked down ADCY8 in the ventromedial hypothalamus to evaluate the need for ADCY8 in the central regulation of glucose homeostasis. Whereas mice fed a standard diet had normal glucose levels, high-fat diet exacerbated glucose intolerance and knock-down mice were incapable of raising their plasma insulin levels. Finally we confirmed that ADCY8 is expressed in human islets. CONCLUSIONS/INTERPRETATIONS Collectively, our findings demonstrate that ADCY8 is required for the physiological activation of glucose-induced signalling pathways in beta cells, for glucose tolerance and for hypothalamic adaptation to a high-fat diet via regulation of islet insulin secretion.
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Affiliation(s)
- Matthieu Raoux
- Université de Bordeaux, CNRS UMR 5248, Chimie et Biologie des Membranes et Nano-objets, Batiment B14, Allée Geoffrey St Hilaire, CS90063, F-33615, Pessac, France
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Dou H, Wang C, Wu X, Yao L, Zhang X, Teng S, Xu H, Liu B, Wu Q, Zhang Q, Hu M, Wang Y, Wang L, Wu Y, Shang S, Kang X, Zheng L, Zhang J, Raoux M, Lang J, Li Q, Su J, Yu X, Chen L, Zhou Z. Calcium influx activates adenylyl cyclase 8 for sustained insulin secretion in rat pancreatic beta cells. Diabetologia 2015; 58:324-33. [PMID: 25381556 DOI: 10.1007/s00125-014-3437-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 10/08/2014] [Indexed: 01/07/2023]
Abstract
AIMS/HYPOTHESIS Insulin is a key metabolic regulator in health and diabetes. In pancreatic beta cells, insulin release is regulated by the major second messengers Ca(2+) and cAMP: exocytosis is triggered by Ca(2+) and mediated by the cAMP/protein kinase A (PKA) signalling pathway. However, the causal link between these two processes in primary beta cells remains undefined. METHODS Time-resolved confocal imaging of fluorescence resonance energy transfer signals was performed to visualise PKA activity, and combined membrane capacitance recordings were used to monitor insulin secretion from patch-clamped rat beta cells. RESULTS Membrane depolarisation-induced Ca(2+) influx caused an increase in cytosolic PKA activity via activating a Ca(2+)-sensitive adenylyl cyclase 8 (ADCY8) subpool. Glucose stimulation triggered coupled Ca(2+) oscillations and PKA activation. ADCY8 knockdown significantly reduced the level of depolarisation-evoked PKA activation and impaired replenishment of the readily releasable vesicle pool. Pharmacological inhibition of PKA by two inhibitors reduced depolarisation-induced PKA activation to a similar extent and reduced the capacity for sustained vesicle exocytosis and insulin release. CONCLUSIONS/INTERPRETATION Our findings suggest that depolarisation-induced Ca(2+) influx plays dual roles in regulating exocytosis in rat pancreatic beta cells by triggering vesicle fusion and replenishing the vesicle pool to support sustained insulin release. Therefore, Ca(2+) influx may be important for glucose-stimulated insulin secretion.
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Affiliation(s)
- Haiqiang Dou
- Institute of Molecular Medicine, Peking University, 5 Yiheyuan Road, Beijing, 100871, China
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Nguyen QV, Caro A, Raoux M, Quotb A, Floderer JB, Bornat Y, Renaud S, Lang J. A novel bioelectronic glucose sensor to process distinct electrical activities of pancreatic beta-cells. Annu Int Conf IEEE Eng Med Biol Soc 2013; 2013:172-175. [PMID: 24109652 DOI: 10.1109/embc.2013.6609465] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Glucose sensors have improved and facilitated therapy for type 1 diabetes. However, they are still not capable to sense all physiological signals and to act in a closed-loop. Pancreatic β-cells have been shaped during evolution as biological sensors and offer the advantage to integrate all physiological signals in addition to glucose. Moreover, biosensors based on these cells may also serve for non-invasive and continuous long-term characterization of β-cells, drug research, tissue engineering and pre-transplantation quality control. β-cells alter their electrical activity upon exposure to glucose and physiological hormones and we have used these properties to design a biosensor. To this end signals were recorded extracellularly from islet cells kept on multi-electrode arrays. Slow and rapid oscillations were observed, both modulated by glucose. Especially slow oscillations are very robust and have an excellent signal/noise ratio. Signal processing functions were designed to separate the two activities to extract and analyze relevant parameters. These parameters correlate very well with either increasing or decreasing glucose concentrations. An electronic device is under construction, based on an embedded FPGA capable of processing multiple channels in parallel. In the future, such a device shall be used as a portable real-time biosensor regulating insulin delivery from a pump.
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Raoux M, Azorin N, Colomban C, Rivoire S, Merrot T, Delmas P, Crest M. Chemicals inducing acute irritant contact dermatitis mobilize intracellular calcium in human keratinocytes. Toxicol In Vitro 2012; 27:402-8. [PMID: 22906572 DOI: 10.1016/j.tiv.2012.08.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Revised: 04/16/2012] [Accepted: 08/02/2012] [Indexed: 01/30/2023]
Abstract
Intracellular Ca(2+) increase is a common feature of multiple cellular pathways associated with receptor and channel activation, mediator secretion and gene regulation. We investigated the possibility of using this Ca(2+) signal as a biomarker for a reaction to chemical irritants of normal human keratinocytes (NHK) in submerged primary cell culture. We tested 14 referenced chemical compounds classified as strong (seven), weak (four) or non- (three) irritants in acute irritant contact dermatitis. We found that the strong irritant compounds tested at 20-40 mM induced an intracellular Ca(2+) increase measurable by spectrofluorimetry in an automated test. Weak and non-irritant compounds however did not increase intracellular Ca(2+) concentration. We further investigated the mechanisms by which the amine heptylamine, classified as a R34 corrosive compound, increases intracellular Ca(2+). Heptylamine (20mM) induced an ATP release that persisted in the absence of intra- and extra-cellular Ca(2+). In addition, we found that this ATP activates NHK purinergic receptors that subsequently cause the increase in intracellular Ca(2+) from sarcoplasmic reticular stores. We conclude that measuring the intracellular Ca(2+) concentration in NHK is a suitable and easy way of determining any potential reaction to soluble chemical compounds.
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Affiliation(s)
- Matthieu Raoux
- Université de la Méditerranée, Centre National de la Recherche Scientifique UMR 6231, Marseille, France
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Raoux M, Bornat Y, Quotb A, Catargi B, Renaud S, Lang J. Non-invasive long-term and real-time analysis of endocrine cells on micro-electrode arrays. J Physiol 2011; 590:1085-91. [PMID: 22199167 DOI: 10.1113/jphysiol.2011.220038] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Non-invasive high-throughput and long-term monitoring of endocrine cells is important for drug research, phenotyping, tissue engineering and pre-transplantation quality control. Here we report a novel approach to obtain simultaneous long-term electrical recordings of different islet cell types using multi-electrode arrays. We implemented wavelet transforms to resolve the low signal/noise ratio inherent to these measurements and extracted on-line a signature specific of cell activity. The architecture employed allows multiplexing a large number of electrodes for high-throughput screening. This method should be of considerable advantage in endocrine research and may be extended to other excitable cells previously not accessible to the technique.
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Affiliation(s)
- Matthieu Raoux
- Université de Bordeaux, CBMN, UMR 5248, F-33600 Pessac, France
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Azorin N, Raoux M, Rodat-Despoix L, Merrot T, Delmas P, Crest M. ATP signalling is crucial for the response of human keratinocytes to mechanical stimulation by hypo-osmotic shock. Exp Dermatol 2011; 20:401-7. [PMID: 21355886 DOI: 10.1111/j.1600-0625.2010.01219.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Touch is detected through receptors located in the skin and the activation of channels in sensory nerve fibres. Epidermal keratinocytes themselves, however, may sense mechanical stimulus and contribute to skin sensation. Here, we showed that the mechanical stimulation of human keratinocytes by hypo-osmotic shock releases adenosine triphosphate (ATP) and increases intracellular calcium. We demonstrated that the release of ATP was found to be calcium independent because emptying the intracellular calcium stores did not cause ATP release; ATP release was still observed in the absence of external calcium and it persisted on chelating cytosolic calcium. On the other hand, the released ATP activated purinergic receptors and mobilized intracellular calcium stores. The resulting depletion of stored calcium led to the activation of capacitative calcium entry. Increase in cytosolic calcium concentration was blocked by the purinergic receptor blocker suramin, phospholipase C inhibitor and apyrase, which hydrolyses ATP. Collectively, our data demonstrate that human keratinocytes are mechanically activated by hypo-osmotic shock, leading first to the release of ATP, which in turn stimulates purinergic receptors, resulting in the mobilization of intracellular calcium and capacitative calcium entry. These results emphasize the crucial role of ATP signalling in the transduction of mechanical stimuli in human keratinocytes.
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Affiliation(s)
- Nathalie Azorin
- Université de la Méditerranée, Centre National de la Recherche Scientifique (CNRS) UMR6231, Marseille, France
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Roger B, Papin J, Vacher P, Raoux M, Mulot A, Dubois M, Kerr-Conte J, Voy BH, Pattou F, Charpentier G, Jonas JC, Moustaïd-Moussa N, Lang J. Adenylyl cyclase 8 is central to glucagon-like peptide 1 signalling and effects of chronically elevated glucose in rat and human pancreatic beta cells. Diabetologia 2011; 54:390-402. [PMID: 21046358 DOI: 10.1007/s00125-010-1955-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 09/08/2010] [Indexed: 01/19/2023]
Abstract
AIMS/HYPOTHESIS Glucose and incretins regulate beta cell function, gene expression and insulin exocytosis via calcium and cAMP. Prolonged exposure to elevated glucose (also termed glucotoxicity) disturbs calcium homeostasis, but little is known about cAMP signalling. We therefore investigated long-term effects of glucose on this pathway with special regard to the incretin glucagon-like peptide 1 (GLP-1). METHODS We exposed INS-1E cells and rat or human islets to different levels of glucose for 3 days and determined functional responses in terms of second messengers (cAMP, Ca(2+)), transcription profiles, activation of cAMP-responsive element (CRE) and secretion by measuring membrane capacitance. Moreover, we modulated directly the abundance of a calcium-sensitive adenylyl cyclase (ADCY8) and GLP-1 receptor (GLP1R). RESULTS GLP-1- or forskolin-mediated increases in cytosolic calcium, cAMP-levels or insulin secretion were largely reduced in INS-1E cells cultured at elevated glucose (>5.5 mmol/l). Statistical analysis of transcription profiles identified cAMP pathways as major targets regulated by glucose. Quantitative PCR confirmed these findings and unravelled marked downregulation of the calcium-sensitive adenylyl cyclase ADCY8 also in rat and in human islets. Re-expression of ADCY8, but not of the GLP1R, recovered GLP-1 signalling in glucotoxicity in INS-1E cells and in rat islets. Moreover, knockdown of this adenylyl cyclase showed that GLP-1-induced cAMP generation, calcium signalling, activation of the downstream target CRE and direct amplification of exocytosis by cAMP-raising agents (evaluated by capacitance measurement) proceeds via ADCY8. CONCLUSIONS/INTERPRETATION cAMP-mediated pathways are modelled by glucose, and downregulation of the calcium-sensitive ADCY8 plays a central role herein, including signalling via the GLP1R.
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Affiliation(s)
- B Roger
- Université de Bordeaux 1, Institut Européen de Chimie et Biologie, UMR CNRS 5248, 2 Av Robert Escarpit, 33607 Pessac, France
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Raoux M, Rodat-Despoix L, Azorin N, Giamarchi A, Hao J, Maingret F, Crest M, Coste B, Delmas P. Mechanosensor Channels in Mammalian Somatosensory Neurons. Sensors (Basel) 2007; 7:1667-1682. [PMID: 28903189 PMCID: PMC3841838 DOI: 10.3390/s7091667] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Accepted: 08/31/2007] [Indexed: 12/11/2022]
Abstract
Mechanoreceptive sensory neurons innervating the skin, skeletal muscles and viscera signal both innocuous and noxious information necessary for proprioception, touch and pain. These neurons are responsible for the transduction of mechanical stimuli into action potentials that propagate to the central nervous system. The ability of these cells to detect mechanical stimuli impinging on them relies on the presence of mechanosensitive channels that transduce the external mechanical forces into electrical and chemical signals. Although a great deal of information regarding the molecular and biophysical properties of mechanosensitive channels in prokaryotes has been accumulated over the past two decades, less is known about the mechanosensitive channels necessary for proprioception and the senses of touch and pain. This review summarizes the most pertinent data on mechanosensitive channels of mammalian somatosensory neurons, focusing on their properties, pharmacology and putative identity.
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Affiliation(s)
- Matthieu Raoux
- Laboratoire de Neurophysiologie Cellulaire, Centre National de la Recherche Scientifique UMR 6150, Université de la Méditerranée, Marseille, France.
| | - Lise Rodat-Despoix
- Laboratoire de Neurophysiologie Cellulaire, Centre National de la Recherche Scientifique UMR 6150, Université de la Méditerranée, Marseille, France.
| | - Nathalie Azorin
- Laboratoire de Neurophysiologie Cellulaire, Centre National de la Recherche Scientifique UMR 6150, Université de la Méditerranée, Marseille, France.
| | - Aurélie Giamarchi
- Laboratoire de Neurophysiologie Cellulaire, Centre National de la Recherche Scientifique UMR 6150, Université de la Méditerranée, Marseille, France.
| | - Jizhe Hao
- Laboratoire de Neurophysiologie Cellulaire, Centre National de la Recherche Scientifique UMR 6150, Université de la Méditerranée, Marseille, France.
| | - François Maingret
- Laboratoire de Neurophysiologie Cellulaire, Centre National de la Recherche Scientifique UMR 6150, Université de la Méditerranée, Marseille, France.
| | - Marcel Crest
- Laboratoire de Neurophysiologie Cellulaire, Centre National de la Recherche Scientifique UMR 6150, Université de la Méditerranée, Marseille, France.
| | - Bertrand Coste
- Laboratoire de Neurophysiologie Cellulaire, Centre National de la Recherche Scientifique UMR 6150, Université de la Méditerranée, Marseille, France.
| | - Patrick Delmas
- Laboratoire de Neurophysiologie Cellulaire, Centre National de la Recherche Scientifique UMR 6150, Université de la Méditerranée, Marseille, France.
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Raoux M, Colomban C, Delmas P, Crest M. The Amine-Containing Cutaneous Irritant Heptylamine Inhibits the Volume-Regulated Anion Channel and Mobilizes Intracellular Calcium in Normal Human Epidermal Keratinocytes. Mol Pharmacol 2007; 71:1685-94. [PMID: 17384225 DOI: 10.1124/mol.106.033324] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Many amines are skin irritants and cause contact dermatitis. However, little is known about their mechanisms of action in keratinocytes except that they induce the release of the inflammatory mediators cytokines and ATP. Here, we tested whether volume-regulated anion channels (VRACs) in primary cultures of normal human epidermal keratinocytes are modulated by the referenced amine-containing cutaneous irritant heptylamine. Under isotonic conditions, we isolated the VRAC current (I(VRAC)) from other conductances using a high Ca(2+)-buffering internal solution. I(VRAC) ran up after patch rupturing and reached a plateau within 15 min. It was reversibly and dose-dependently inhibited by heptylamine with an IC(50) value of 260 microM. Cell-swelling caused by the application of a hypotonic solution increased 2.7-fold I(VRAC) and reduced the inhibition of VRAC by heptylamine with a dose-response curve shifted approximately 10-fold to the right. In addition, we showed, using cell-attached patch recordings, that adding heptylamine to the bath inhibited VRAC activity. This suggests that heptylamine diffuses into the membrane to inhibit VRAC. Finally, we demonstrated that heptylamine induced Ca(2+)-store depletion and that VRAC inhibition was not caused by the increase in cytosolic Ca(2+). Taken together, these results identify heptylamine as a blocker of VRAC and suggest that Ca(2+)-store depletion may be involved in mechanisms of irritant contact dermatitis caused by heptylamine.
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Affiliation(s)
- Matthieu Raoux
- Laboratoire de Neurophysiologie Cellulaire, CNRS UMR 6150, IFR Jean Roche, Faculté de Médecine, Université de la Méditerranée, Boulevard Pierre Dramard, 13916, Marseille Cedex 20, France
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Giamarchi A, Padilla F, Coste B, Raoux M, Crest M, Honoré E, Delmas P. The versatile nature of the calcium-permeable cation channel TRPP2. EMBO Rep 2006; 7:787-93. [PMID: 16880824 PMCID: PMC1525146 DOI: 10.1038/sj.embor.7400745] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Accepted: 06/02/2006] [Indexed: 12/19/2022] Open
Abstract
TRPP2 is a member of the transient receptor potential (TRP) superfamily of cation channels, which is mutated in autosomal dominant polycystic kidney disease (ADPKD). TRPP2 is thought to function with polycystin 1-a large integral protein-as part of a multiprotein complex involved in transducing Ca(2+)-dependent information. TRPP2 has been implicated in various biological functions including cell proliferation, sperm fertilization, mating behaviour, mechanosensation and asymmetric gene expression. Although its function as a Ca(2+)-permeable cation channel is well established, its precise role in the plasma membrane, the endoplasmic reticulum and the cilium is controversial. Recent studies suggest that TRPP2 function is highly dependent on the subcellular compartment of expression, and is regulated by many interactions with adaptor proteins. This review summarizes the most pertinent evidence about the properties of TRPP2 channels, focusing on the compartment-specific functions of mammalian TRPP2.
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Affiliation(s)
- Aurélie Giamarchi
- Laboratoire de Neurophysiologie Cellulaire, CNRS, UMR 6150, Faculté de Médecine, IFR Jean Roche, Boulevard Pierre Dramard, 13916 Marseille Cedex 20, France
| | - Françoise Padilla
- Laboratoire de Neurophysiologie Cellulaire, CNRS, UMR 6150, Faculté de Médecine, IFR Jean Roche, Boulevard Pierre Dramard, 13916 Marseille Cedex 20, France
| | - Bertrand Coste
- Laboratoire de Neurophysiologie Cellulaire, CNRS, UMR 6150, Faculté de Médecine, IFR Jean Roche, Boulevard Pierre Dramard, 13916 Marseille Cedex 20, France
| | - Matthieu Raoux
- Laboratoire de Neurophysiologie Cellulaire, CNRS, UMR 6150, Faculté de Médecine, IFR Jean Roche, Boulevard Pierre Dramard, 13916 Marseille Cedex 20, France
| | - Marcel Crest
- Laboratoire de Neurophysiologie Cellulaire, CNRS, UMR 6150, Faculté de Médecine, IFR Jean Roche, Boulevard Pierre Dramard, 13916 Marseille Cedex 20, France
| | - Eric Honoré
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, 660, Route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
| | - Patrick Delmas
- Laboratoire de Neurophysiologie Cellulaire, CNRS, UMR 6150, Faculté de Médecine, IFR Jean Roche, Boulevard Pierre Dramard, 13916 Marseille Cedex 20, France
- Tel: +00 33 4 91 69 89 70; Fax: 00 33 4 91 69 89 77
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Delmas P, Padilla F, Osorio N, Coste B, Raoux M, Crest M. Polycystins, calcium signaling, and human diseases. Biochem Biophys Res Commun 2004; 322:1374-83. [PMID: 15336986 DOI: 10.1016/j.bbrc.2004.08.044] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2004] [Indexed: 01/26/2023]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a major, inherited nephropathy affecting over 1:1000 of the worldwide population. It is a systemic condition with frequent hepatic and cardiovascular manifestations in addition to the progressive development of fluid-filled cysts from the tubules and collecting ducts of affected kidneys. The pathogenesis of cyst formation is currently thought to involve increased proliferation of epithelial cells, mild dedifferentiation, and fluid accumulation. In the past decade, study of ADPKD led to the discovery of a unique family of highly complex proteins, the polycystins. Loss-of-function mutations in either of two polycystin proteins, polycystin-1 or polycystin-2, give rise to ADPKD. These proteins are thought to function together as part of a multiprotein complex that may initiate Ca2+ signals, directing attention to the regulation of intracellular Ca2+ as a possible misstep that participates in cyst formation. Here we review what is known about the Ca2+ signaling functions of polycystin proteins and focus on findings that have significantly advanced our physiological insight. Special attention is paid to the recently discovered role of these proteins in the mechanotransduction of the renal primary cilium and the model it suggests.
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Affiliation(s)
- Patrick Delmas
- Laboratoire de Neurophysiologie Cellulaire, CNRS-UMR 6150, Faculté de Médecine, IFR Jean Roche, Bd. Pierre Dramard, 13916 Marseille Cedex 20, France.
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Marescaux J, Doffoel M, Raoux M, Grenier JF. [Surgical treatment of pathologic obesity]. Rev Prat 1982; 32:375-8, 381-5. [PMID: 7058306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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