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Olsen C, Wang C, Abadpour S, Lundanes E, Hansen AS, Skottvoll FS, Scholz H, Wilson SR. Determination of insulin secretion from stem cell-derived islet organoids with liquid chromatography-tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2023; 1215:123577. [PMID: 36542899 DOI: 10.1016/j.jchromb.2022.123577] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 12/05/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Abstract
Organoids are laboratory-grown 3D organ models, mimicking human organs for e.g. drug development and personalized therapy. Islet organoids (typically 100-200 µm), which can be grown from the patient́s own cells, are emerging as prototypes for transplantation-based therapy of diabetes. Selective methods for quantifying insulin production from islet organoids are needed, but sensitivity and carry-over have been major bottlenecks in previous efforts. We have developed a reverse phase liquid chromatography-tandem mass spectrometry (RPLC-MS/MS) method for studying the insulin secretion of islet organoids. In contrast to our previous attempts using nano-scale LC columns, conventional 2.1 mm inner diameter LC column (combined with triple quadrupole mass spectrometry) was well suited for sensitive and selective measurements of insulin secreted from islet organoids with low microliter-scale samples. Insulin is highly prone to carry-over, so standard tubings and injector parts were replaced with shielded fused silica connectors. As samples were expected to be very limited, an extended Box-Behnken experimental design for the MS settings was conducted to maximize performance. The finale method has excellent sensitivity, accuracy and precision (limit of detection: ≤0.2 pg/µL, relative error: ≤±10%, relative standard deviation: <10%), and was well suited for measuring 20 µL amounts of Krebs buffer containing insulin secreted from islet organoids.
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Affiliation(s)
- Christine Olsen
- Department of Chemistry, University of Oslo, Blindern, Oslo, Norway; Hybrid Technology Hub-Centre of Excellence, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Chencheng Wang
- Hybrid Technology Hub-Centre of Excellence, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway; Department of Transplant Medicine and Institute for Surgical Research, Oslo University Hospital, Oslo, Norway
| | - Shadab Abadpour
- Hybrid Technology Hub-Centre of Excellence, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway; Department of Transplant Medicine and Institute for Surgical Research, Oslo University Hospital, Oslo, Norway
| | - Elsa Lundanes
- Department of Chemistry, University of Oslo, Blindern, Oslo, Norway
| | | | | | - Hanne Scholz
- Hybrid Technology Hub-Centre of Excellence, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway; Department of Transplant Medicine and Institute for Surgical Research, Oslo University Hospital, Oslo, Norway
| | - Steven Ray Wilson
- Department of Chemistry, University of Oslo, Blindern, Oslo, Norway; Hybrid Technology Hub-Centre of Excellence, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway.
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Porter JM, Guerassimoff L, Castiello FR, Charette A, Tabrizian M. INGAP-Peptide Variants as a Novel Therapy for Type 1 Diabetes: Effect on Human Islet Insulin Secretion and Gene Expression. Pharmaceutics 2022; 14:pharmaceutics14091833. [PMID: 36145580 PMCID: PMC9502412 DOI: 10.3390/pharmaceutics14091833] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/24/2022] [Accepted: 08/29/2022] [Indexed: 11/16/2022] Open
Abstract
Islet transplantation offers a long-term cure for Type 1 Diabetes (T1D), freeing patients from daily insulin injections. Therapeutic peptides have shown potential to increase the insulin output of pancreatic islets, maximizing the impact of grafted cells. The islet neogenesis-associated protein (INGAP), and its bioactive core (INGAP-P), stimulate beta-cell function and viability, offering the possibility for islet treatment prior to implant. However, dosing efficacy is limited by low circulation time and enzyme degradation. This proof-of-concept study presents the investigation of novel molecular variants of INGAP-P to find a more bioactive form. Custom-designed peptide variants of INGAP-P were synthesized and tested for their effect on the insulin secretion and gene expression of live human islets. We exposed the live islets of five donors to varying glucose concentrations with INGAP-P variants in solution. We identified four peptide variants (I9, I15Tyr, I19 and I15Cys) which displayed statistically significant enhancements over negative controls (representing a 1.6–2.8-fold increase in stimulation index). This is the first study that has assessed these INGAP-P variants in human islets. It highlights the potential for customized peptides for type 1 diabetes therapy and provides a foundation for future peptide-screening experiments.
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Affiliation(s)
- James M. Porter
- Department of Biological and Biomedical Engineering, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3A 0G4, Canada
| | - Léa Guerassimoff
- Department of Biological and Biomedical Engineering, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3A 0G4, Canada
- Campus MIL, l’Université de Montréal, Montreal, QC H2V 0B3, Canada
| | - Francisco Rafael Castiello
- Department of Biological and Biomedical Engineering, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3A 0G4, Canada
| | - André Charette
- Campus MIL, l’Université de Montréal, Montreal, QC H2V 0B3, Canada
| | - Maryam Tabrizian
- Department of Biological and Biomedical Engineering, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3A 0G4, Canada
- Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC H3A 1G1, Canada
- Correspondence:
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Mechanistic Investigation of GHS-R Mediated Glucose-Stimulated Insulin Secretion in Pancreatic Islets. Biomolecules 2022; 12:biom12030407. [PMID: 35327599 PMCID: PMC8945998 DOI: 10.3390/biom12030407] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/19/2022] [Accepted: 02/27/2022] [Indexed: 02/07/2023] Open
Abstract
Ghrelin receptor, a growth hormone secretagogue receptor (GHS-R), is expressed in the pancreas. Emerging evidence indicates that GHS-R is involved in the regulation of glucose-stimulated insulin secretion (GSIS), but the mechanism by which GHS-R regulates GSIS in the pancreas is unclear. In this study, we investigated the role of GHS-R on GSIS in detail using global Ghsr−/− mice (in vivo) and Ghsr-ablated pancreatic islets (ex vivo). GSIS was attenuated in both Ghsr−/− mice and Ghsr-ablated islets, while the islet morphology was similar between WT and Ghsr−/− mice. To elucidate the mechanism underpinning Ghsr-mediated GSIS, we investigated the key steps of the GSIS signaling cascade. The gene expression of glucose transporter 2 (Glut2) and the glucose-metabolic intermediate—glucose-6-phosphate (G6P) were reduced in Ghsr-ablated islets, supporting decreased glucose uptake. There was no difference in mitochondrial DNA content in the islets of WT and Ghsr−/− mice, but the ATP/ADP ratio in Ghsr−/− islets was significantly lower than that of WT islets. Moreover, the expression of pancreatic and duodenal homeobox 1 (Pdx1), as well as insulin signaling genes of insulin receptor (IR) and insulin receptor substrates 1 and 2 (IRS1/IRS2), was downregulated in Ghsr−/− islets. Akt is the key mediator of the insulin signaling cascade. Concurrently, Akt phosphorylation was reduced in the pancreas of Ghsr−/− mice under both insulin-stimulated and homeostatic conditions. These findings demonstrate that GHS-R ablation affects key components of the insulin signaling pathway in the pancreas, suggesting the existence of a cross-talk between GHS-R and the insulin signaling pathway in pancreatic islets, and GHS-R likely regulates GSIS via the Akt-Pdx1-GLUT2 pathway.
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Gaus B, Brüning D, Groß S, Müller M, Rustenbeck I. The changing view of insulin granule mobility: From conveyor belt to signaling hub. Front Endocrinol (Lausanne) 2022; 13:983152. [PMID: 36120467 PMCID: PMC9478610 DOI: 10.3389/fendo.2022.983152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/11/2022] [Indexed: 11/28/2022] Open
Abstract
Before the advent of TIRF microscopy the fate of the insulin granule prior to secretion was deduced from biochemical investigations, electron microscopy and electrophysiological measurements. Since Calcium-triggered granule fusion is indisputably necessary to release insulin into the extracellular space, much effort was directed to the measure this event at the single granule level. This has also been the major application of the TIRF microscopy of the pancreatic beta cell when it became available about 20 years ago. To better understand the metabolic modulation of secretion, we were interested to characterize the entirety of the insulin granules which are localized in the vicinity of the plasma membrane to identify the characteristics which predispose to fusion. In this review we concentrate on how the description of granule mobility in the submembrane space has evolved as a result of progress in methodology. The granules are in a state of constant turnover with widely different periods of residence in this space. While granule fusion is associated +with prolonged residence and decreased lateral mobility, these characteristics may not only result from binding to the plasma membrane but also from binding to the cortical actin web, which is present in the immediate submembrane space. While granule age as such affects granule mobility and fusion probability, the preceding functional states of the beta cell leave their mark on these parameters, too. In summary, the submembrane granules form a highly dynamic heterogeneous population and contribute to the metabolic memory of the beta cells.
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Affiliation(s)
- Bastian Gaus
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Braunschweig, Germany
| | - Dennis Brüning
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Braunschweig, Germany
| | - Sofie Groß
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Braunschweig, Germany
| | - Michael Müller
- Institute of Dynamics and Vibrations, Technische Universität Braunschweig, Braunschweig, Germany
| | - Ingo Rustenbeck
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Braunschweig, Germany
- *Correspondence: Ingo Rustenbeck,
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Campbell SA, Bégin J, McDonald CL, Vanderkruk B, Stephan TL, Hoffman BG. H3K4 Trimethylation Is Required for Postnatal Pancreatic Endocrine Cell Functional Maturation. Diabetes 2021; 70:2568-2579. [PMID: 34376477 DOI: 10.2337/db20-1214] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 08/03/2021] [Indexed: 11/13/2022]
Abstract
During pancreas development, endocrine progenitors differentiate into the islet cell subtypes, which undergo further functional maturation in postnatal islet development. In islet β-cells, genes involved in glucose-stimulated insulin secretion are activated, and glucose exposure increases the insulin response as β-cells mature. We investigated the role of H3K4 trimethylation in endocrine cell differentiation and functional maturation by disrupting TrxG complex histone methyltransferase activity in mouse endocrine progenitors. In the embryo, genetic inactivation of TrxG component Dpy30 in NEUROG3+ cells did not affect the number of endocrine progenitors or endocrine cell differentiation. H3K4 trimethylation was progressively lost in postnatal islets, and the mice displayed elevated nonfasting and fasting glycemia as well as impaired glucose tolerance by postnatal day 24. Although postnatal endocrine cell proportions were equivalent to controls, islet RNA sequencing revealed a downregulation of genes involved in glucose-stimulated insulin secretion and an upregulation of immature β-cell genes. Comparison of histone modification enrichment profiles in NEUROG3+ endocrine progenitors and mature islets suggested that genes downregulated by loss of H3K4 trimethylation more frequently acquire active histone modifications during maturation. Taken together, these findings suggest that H3K4 trimethylation is required for the activation of genes involved in the functional maturation of pancreatic islet endocrine cells.
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Affiliation(s)
- Stephanie A Campbell
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- Diabetes Research Group, British Columbia Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Jocelyn Bégin
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- Diabetes Research Group, British Columbia Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Cassandra L McDonald
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ben Vanderkruk
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- Diabetes Research Group, British Columbia Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Tabea L Stephan
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
| | - Brad G Hoffman
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
- Diabetes Research Group, British Columbia Children's Hospital Research Institute, Vancouver, British Columbia, Canada
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Gaus B, Brüning D, Hatlapatka K, Rustenbeck I. Changes in granule mobility and age contribute to changes in insulin secretion after desensitization or rest. BMJ Open Diabetes Res Care 2021; 9:9/1/e002394. [PMID: 34620619 PMCID: PMC8499263 DOI: 10.1136/bmjdrc-2021-002394] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 09/14/2021] [Indexed: 12/17/2022] Open
Abstract
INTRODUCTION Functional impairment of the stimulus secretion coupling in pancreatic beta cells is an essential component of type 2 diabetes. It is known that prolonged stimulation desensitizes the secretion of insulin and thus contributes to beta cell dysfunction. Beta cell rest, in contrast, was shown to enhance the secretory response. Here, the underlying mechanisms were investigated. RESEARCH DESIGN AND METHODS To characterize the consequences of desensitization or rest for the number and mobility of submembrane granules, insulin-secreting MIN6 cells were desensitized by 18-hour culture with 500 µM tolbutamide or rested by 18-hour culture with 1 µM clonidine. The granules were labeled by hIns-EGFP or hIns-DsRed E5, imaged by TIRF microscopy of the cell footprint area and analyzed with an observer-independent program. Additionally, the insulin content and secretion were measured. RESULTS Concurrent with the insulin content, submembrane granules were only slightly reduced after desensitization but markedly increased after rest. Both types of pretreatment diminished arrivals and departures of granules in the submembrane space and increased the proportion of immobile long-term resident granules, but desensitization lowered and rest increased the number of exocytoses, in parallel with the effect on insulin secretion. Labeling with hIns-DsRed E5 ('timer') showed that desensitization did not affect the proportion of aged granules, whereas rest increased it. Aged granules showed a high mobility and made up only a minority of long-term residents. Long-term resident granules were more numerous after rest and had a lower lateral mobility, suggesting a firmer attachment to the membrane. CONCLUSION The number, mobility and age of submembrane granules reflect the preceding functional states of insulin-secreting cells. Representing the pool of releasable granules, their quantity and quality may thus form part of the beta cell memory on renewed stimulation.
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Affiliation(s)
- Bastian Gaus
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Braunschweig, Germany
| | - Dennis Brüning
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Braunschweig, Germany
| | - Kathrin Hatlapatka
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Braunschweig, Germany
- DHD-Consulting GmbH, Hildesheim, Germany
| | - Ingo Rustenbeck
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Braunschweig, Germany
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7
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A High-Content Screen for the Identification of Plant Extracts with Insulin Secretion-Modulating Activity. Pharmaceuticals (Basel) 2021; 14:ph14080809. [PMID: 34451906 PMCID: PMC8402219 DOI: 10.3390/ph14080809] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/10/2021] [Accepted: 08/10/2021] [Indexed: 12/18/2022] Open
Abstract
Bioactive plant compounds and extracts are of special interest for the development of pharmaceuticals. Here, we describe the screening of more than 1100 aqueous plant extracts and synthetic reference compounds for their ability to stimulate or inhibit insulin secretion. To quantify insulin secretion in living MIN6 β cells, an insulin–Gaussia luciferase (Ins-GLuc) biosensor was used. Positive hits included extracts from Quillaja saponaria, Anagallis arvensis, Sapindus mukorossi, Gleditsia sinensis and Albizia julibrissin, which were identified as insulin secretion stimulators, whereas extracts of Acacia catechu, Myrtus communis, Actaea spicata L., Vaccinium vitis-idaea and Calendula officinalis were found to exhibit insulin secretion inhibitory properties. Gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) were used to characterize several bioactive compounds in the selected plant extracts, and these bioactives were retested for their insulin-modulating properties. Overall, we identified several plant extracts and some of their bioactive compounds that may be used to manipulate pancreatic insulin secretion.
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Rustenbeck I, Schulze T, Morsi M, Alshafei M, Panten U. What Is the Metabolic Amplification of Insulin Secretion and Is It (Still) Relevant? Metabolites 2021; 11:metabo11060355. [PMID: 34199454 PMCID: PMC8229681 DOI: 10.3390/metabo11060355] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/27/2021] [Accepted: 05/31/2021] [Indexed: 12/24/2022] Open
Abstract
The pancreatic beta-cell transduces the availability of nutrients into the secretion of insulin. While this process is extensively modified by hormones and neurotransmitters, it is the availability of nutrients, above all glucose, which sets the process of insulin synthesis and secretion in motion. The central role of the mitochondria in this process was identified decades ago, but how changes in mitochondrial activity are coupled to the exocytosis of insulin granules is still incompletely understood. The identification of ATP-sensitive K+-channels provided the link between the level of adenine nucleotides and the electrical activity of the beta cell, but the depolarization-induced Ca2+-influx into the beta cells, although necessary for stimulated secretion, is not sufficient to generate the secretion pattern as produced by glucose and other nutrient secretagogues. The metabolic amplification of insulin secretion is thus the sequence of events that enables the secretory response to a nutrient secretagogue to exceed the secretory response to a purely depolarizing stimulus and is thus of prime importance. Since the cataplerotic export of mitochondrial metabolites is involved in this signaling, an orienting overview on the topic of nutrient secretagogues beyond glucose is included. Their judicious use may help to define better the nature of the signals and their mechanism of action.
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Affiliation(s)
- Ingo Rustenbeck
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
- Correspondence: ; Tel.: +49-(0)53-139-156-70
| | - Torben Schulze
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
| | - Mai Morsi
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
- Department of Pharmacology, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt
| | - Mohammed Alshafei
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
| | - Uwe Panten
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (T.S.); (M.M.); (M.A.); (U.P.)
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9
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Früh E, Elgert C, Eggert F, Scherneck S, Rustenbeck I. Glucagonotropic and Glucagonostatic Effects of KATP Channel Closure and Potassium Depolarization. Endocrinology 2021; 162:5892293. [PMID: 32790843 DOI: 10.1210/endocr/bqaa136] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 08/05/2020] [Indexed: 02/08/2023]
Abstract
The role of depolarization in the inverse glucose-dependence of glucagon secretion was investigated by comparing the effects of KATP channel block and of high potassium. The secretion of glucagon and insulin by perifused mouse islets was simultaneously measured. Lowering glucose raised glucagon secretion before it decreased insulin secretion, suggesting an alpha cell-intrinsic signal recognition. Raising glucose affected glucagon and insulin secretion at the same time. However, depolarization by tolbutamide, gliclazide, or 15 mM KCl increased insulin secretion before the glucagon secretion receded. In contrast to the robust depolarizing effect of arginine and KCl (15 and 40 mM) on single alpha cells, tolbutamide was of variable efficacy. Only when applied before other depolarizing agents had tolbutamide a consistent depolarizing effect and regularly increased the cytosolic Ca2+ concentration. When tested on inside-out patches tolbutamide was as effective on alpha cells as on beta cells. In the presence of 1 µM clonidine, to separate insulinotropic from glucagonotropic effects, both 500 µM tolbutamide and 30 µM gliclazide increased glucagon secretion significantly, but transiently. The additional presence of 15 or 40 mM KCl in contrast led to a marked and lasting increase of the glucagon secretion. The glucagon secretion by SUR1 knockout islets was not increased by tolbutamide, whereas 40 mM KCl was of unchanged efficiency. In conclusion a strong and sustained depolarization is compatible with a marked and lasting glucagon secretion. KATP channel closure in alpha cells is less readily achieved than in beta cells, which may explain the moderate and transient glucagonotropic effect.
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Affiliation(s)
- Eike Früh
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Braunschweig, Germany
| | - Christin Elgert
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Braunschweig, Germany
| | - Frank Eggert
- Institute of Psychology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Stephan Scherneck
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Braunschweig, Germany
| | - Ingo Rustenbeck
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, Braunschweig, Germany
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10
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White KL, Singla J, Loconte V, Chen JH, Ekman A, Sun L, Zhang X, Francis JP, Li A, Lin W, Tseng K, McDermott G, Alber F, Sali A, Larabell C, Stevens RC. Visualizing subcellular rearrangements in intact β cells using soft x-ray tomography. SCIENCE ADVANCES 2020; 6:eabc8262. [PMID: 33298443 PMCID: PMC7725475 DOI: 10.1126/sciadv.abc8262] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 10/21/2020] [Indexed: 05/21/2023]
Abstract
Characterizing relationships between cell structures and functions requires mesoscale mapping of intact cells showing subcellular rearrangements following stimulation; however, current approaches are limited in this regard. Here, we report a unique application of soft x-ray tomography to generate three-dimensional reconstructions of whole pancreatic β cells at different time points following glucose-stimulated insulin secretion. Reconstructions following stimulation showed distinct insulin vesicle distribution patterns reflective of altered vesicle pool sizes as they travel through the secretory pathway. Our results show that glucose stimulation caused rapid changes in biochemical composition and/or density of insulin packing, increased mitochondrial volume, and closer proximity of insulin vesicles to mitochondria. Costimulation with exendin-4 (a glucagon-like peptide-1 receptor agonist) prolonged these effects and increased insulin packaging efficiency and vesicle maturation. This study provides unique perspectives on the coordinated structural reorganization and interactions of organelles that dictate cell responses.
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Affiliation(s)
- Kate L White
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA.
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jitin Singla
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA
- Institute for Quantitative and Computational Biosciences, Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Valentina Loconte
- iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jian-Hua Chen
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Axel Ekman
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Liping Sun
- iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xianjun Zhang
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA
| | - John Paul Francis
- Department of Computer Science, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA
| | - Angdi Li
- iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Wen Lin
- Department of Chemistry, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA
| | - Kaylee Tseng
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA
| | - Gerry McDermott
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Frank Alber
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA
- Institute for Quantitative and Computational Biosciences, Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Andrej Sali
- California Institute for Quantitative Biosciences, Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Carolyn Larabell
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Raymond C Stevens
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA.
- iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Department of Chemistry, Bridge Institute, USC Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA
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11
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Müller M, Glombek M, Powitz J, Brüning D, Rustenbeck I. A Cellular Automaton Model as a First Model-Based Assessment of Interacting Mechanisms for Insulin Granule Transport in Beta Cells. Cells 2020; 9:E1487. [PMID: 32570905 PMCID: PMC7348896 DOI: 10.3390/cells9061487] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/16/2020] [Accepted: 06/17/2020] [Indexed: 12/31/2022] Open
Abstract
In this paper a first model is derived and applied which describes the transport of insulin granules through the cell interior and at the membrane of a beta cell. A special role is assigned to the actin network, which significantly influences the transport. For this purpose, microscopically measured actin networks are characterized and then further ones are artificially generated. In a Cellular Automaton model, phenomenological laws for granule movement are formulated and implemented. Simulation results are compared with experiments, primarily using TIRF images and secretion rates. In this respect, good similarities are already apparent. The model is a first useful approach to describe complex granule transport processes in beta cells, and offers great potential for future extensions. Furthermore, the model can be used as a tool to validate hypotheses and associated mechanisms regarding their effect on exocytosis or other processes. For this purpose, the source code for the model is provided online.
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Affiliation(s)
- Michael Müller
- Institute of Dynamics and Vibrations, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (M.G.); (J.P.)
| | - Mathias Glombek
- Institute of Dynamics and Vibrations, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (M.G.); (J.P.)
| | - Jeldrick Powitz
- Institute of Dynamics and Vibrations, Technische Universität Braunschweig, D38106 Braunschweig, Germany; (M.G.); (J.P.)
| | - Dennis Brüning
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany;
| | - Ingo Rustenbeck
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, D38106 Braunschweig, Germany;
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12
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Altered β-Cell Calcium Dynamics via Electric Field Exposure. Ann Biomed Eng 2020; 49:106-114. [PMID: 32323041 DOI: 10.1007/s10439-020-02517-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 04/15/2020] [Indexed: 10/24/2022]
Abstract
Electric field stimulation has long been investigated with results supporting its therapeutic potential; however, its effects on insulin secreting cells has yet to be fully elucidated. Herein we explored the effects of physiological direct current (DC) electric field stimulation on the intracellular calcium dynamics of mouse derived βTC-6 insulinoma cells. This electrical stimulation resulted in an elevation in intracellular calcium along with a rise in calcium spiking activity. Further investigation indicated that the rise in intracellular calcium was mediated by an influx of calcium via L-type voltage gated calcium channels. Additionally, the effects of the electric field stimulation were able to induce insulin secretion in the absence of glucose stimulation. Given these results, DC electric field stimulation could be used as a non-invasive tool to modulate intracellular calcium dynamics and insulin secretion of β-cells for therapeutic application.
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13
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Jennemann R, Kaden S, Volz M, Nordström V, Herzer S, Sandhoff R, Gröne HJ. Gangliosides modulate insulin secretion by pancreatic beta cells under glucose stress. Glycobiology 2020; 30:722-734. [PMID: 32149357 DOI: 10.1093/glycob/cwaa022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 02/18/2020] [Accepted: 03/02/2020] [Indexed: 02/06/2023] Open
Abstract
In pancreatic beta cells, the entry of glucose and downstream signaling for insulin release is regulated by the glucose transporter 2 (Glut2) in rodents. Dysfunction of the insulin-signaling cascade may lead to diabetes mellitus. Gangliosides, sialic acid-containing glycosphingolipids (GSLs), have been reported to modulate the function of several membrane proteins.Murine islets express predominantly sialylated GSLs, particularly the simple gangliosides GM3 and GD3 having a potential modulatory role in Glut2 activity. Conditional, tamoxifen-inducible gene targeting in pancreatic islets has now shown that mice lacking the glucosylceramide synthase (Ugcg), which represents the rate-limiting enzyme in GSL biosynthesis, displayed impaired glucose uptake and showed reduced insulin secretion. Consequently, mice with pancreatic GSL deficiency had higher blood glucose levels than respective controls after intraperitoneal glucose application. High-fat diet feeding enhanced this effect. GSL-deficient islets did not show apoptosis or ER stress and displayed a normal ultrastructure. Their insulin content, size and number were similar as in control islets. Isolated beta cells from GM3 synthase null mice unable to synthesize GM3 and GD3 also showed lower glucose uptake than respective control cells, corroborating the results obtained from the cell-specific model. We conclude that in particular the negatively charged gangliosides GM3 and GD3 of beta cells positively influence Glut2 function to adequately respond to high glucose loads.
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Affiliation(s)
- Richard Jennemann
- Department of Cellular and Molecular Pathology, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg 69120, Germany.,Lipid Pathobiochemistry Group, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg 69120, Germany
| | - Sylvia Kaden
- Department of Cellular and Molecular Pathology, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg 69120, Germany
| | - Martina Volz
- Department of Cellular and Molecular Pathology, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg 69120, Germany
| | - Viola Nordström
- Department of Cellular and Molecular Pathology, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg 69120, Germany
| | - Silke Herzer
- Department of Cellular and Molecular Pathology, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg 69120, Germany
| | - Roger Sandhoff
- Department of Cellular and Molecular Pathology, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg 69120, Germany.,Lipid Pathobiochemistry Group, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg 69120, Germany
| | - Hermann-Josef Gröne
- Department of Cellular and Molecular Pathology, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg 69120, Germany.,Institute of Pharmacology, University of Marburg, Karl-von-Frisch-Straße 2 Marburg 35043, Germany
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14
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Fu J, Githaka JM, Dai X, Plummer G, Suzuki K, Spigelman AF, Bautista A, Kim R, Greitzer-Antes D, Fox JEM, Gaisano HY, MacDonald PE. A glucose-dependent spatial patterning of exocytosis in human β-cells is disrupted in type 2 diabetes. JCI Insight 2019; 5:127896. [PMID: 31085831 DOI: 10.1172/jci.insight.127896] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Impaired insulin secretion in type 2 diabetes (T2D) is linked to reduced insulin granule docking, disorganization of the exocytotic site, and an impaired glucose-dependent facilitation of insulin exocytosis. We show in β-cells from 80 human donors that the glucose-dependent amplification of exocytosis is disrupted in T2D. Spatial analyses of granule fusion, visualized by total internal reflection fluorescence (TIRF) microscopy in 24 of these donors, demonstrate that these are non-random across the surface of β-cells from donors with no diabetes (ND). The compartmentalization of events occurs within regions defined by concurrent or recent membrane-resident secretory granules. This organization, and the number of membrane-associated granules, is glucose-dependent and notably impaired in T2D β-cells. Mechanistically, multi-channel Kv2.1 clusters contribute to maintaining the density of membrane-resident granules and the number of fusion 'hotspots', while SUMOylation sites at the channel N- (K145) and C-terminus (K470) determine the relative proportion of fusion events occurring within these regions. Thus, a glucose-dependent compartmentalization of fusion, regulated in part by a structural role for Kv2.1, is disrupted in β-cells from donors with type 2 diabetes.
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Affiliation(s)
- Jianyang Fu
- Alberta Diabetes Institute and Department of Pharmacology and
| | | | - Xiaoqing Dai
- Alberta Diabetes Institute and Department of Pharmacology and
| | - Gregory Plummer
- Alberta Diabetes Institute and Department of Pharmacology and
| | - Kunimasa Suzuki
- Alberta Diabetes Institute and Department of Pharmacology and
| | | | - Austin Bautista
- Alberta Diabetes Institute and Department of Pharmacology and
| | - Ryekjang Kim
- Alberta Diabetes Institute and Department of Pharmacology and
| | - Dafna Greitzer-Antes
- Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada
| | | | - Herbert Y Gaisano
- Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada
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15
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Nasteska D, Hodson DJ. The role of beta cell heterogeneity in islet function and insulin release. J Mol Endocrinol 2018; 61:R43-R60. [PMID: 29661799 PMCID: PMC5976077 DOI: 10.1530/jme-18-0011] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 04/16/2018] [Indexed: 12/15/2022]
Abstract
It is becoming increasingly apparent that not all insulin-secreting beta cells are equal. Subtle differences exist at the transcriptomic and protein expression levels, with repercussions for beta cell survival/proliferation, calcium signalling and insulin release. Notably, beta cell heterogeneity displays plasticity during development, metabolic stress and type 2 diabetes mellitus (T2DM). Thus, heterogeneity or lack thereof may be an important contributor to beta cell failure during T2DM in both rodents and humans. The present review will discuss the molecular and cellular features of beta cell heterogeneity at both the single-cell and islet level, explore how this influences islet function and insulin release and look into the alterations that may occur during obesity and T2DM.
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Affiliation(s)
- Daniela Nasteska
- Institute of Metabolism and Systems Research (IMSR)University of Birmingham, Edgbaston, UK
- Centre for EndocrinologyDiabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
- COMPARE University of Birmingham and University of Nottingham MidlandsBirmingham, UK
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR)University of Birmingham, Edgbaston, UK
- Centre for EndocrinologyDiabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
- COMPARE University of Birmingham and University of Nottingham MidlandsBirmingham, UK
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