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Ruiz-Santiago C, Rodríguez-Pinacho CV, Pérez-Sánchez G, Acosta-Cruz E. Effects of selective serotonin reuptake inhibitors on endocrine system (Review). Biomed Rep 2024; 21:128. [PMID: 39070109 PMCID: PMC11273194 DOI: 10.3892/br.2024.1816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 06/10/2024] [Indexed: 07/30/2024] Open
Abstract
Selective serotonin reuptake inhibitors (SSRIs) are typically prescribed for treating major depressive disorder (MDD) due to their high efficacy. These drugs function by inhibiting the reuptake of serotonin [also termed 5-hydroxytryptamine (5-HT)], which raises the levels of 5-HT in the synaptic cleft, leading to prolonged activation of postsynaptic 5-HT receptors. Despite the therapeutic benefits of SSRIs, this mechanism of action also disturbs the neuroendocrine response. Hypothalamic-pituitary-adrenal (HPA) axis activity is strongly linked to both MDD and the response to antidepressants, owing to the intricate interplay within the serotonergic system, which regulates feeding, water intake, sexual drive, reproduction and circadian rhythms. The aim of the present review was to provide up-to-date evidence for the proposed effects of SSRIs, such as fluoxetine, citalopram, escitalopram, paroxetine, sertraline and fluvoxamine, on the endocrine system. For this purpose, the literature related to the effects of SSRIs on the endocrine system was searched using the PubMed database. According to the available literature, SSRIs may have an adverse effect on glucose metabolism, sexual function and fertility by dysregulating the function of the HPA axis, pancreas and gonads. Therefore, considering that SSRIs are often prescribed for extended periods, it is crucial to monitor the patient closely with particular attention to the function of the endocrine system.
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Affiliation(s)
- Carolina Ruiz-Santiago
- Department of Biotechnology, Faculty of Chemistry, Universidad Autónoma de Coahuila, Saltillo Coahuila 25280, México
| | | | - Gilberto Pérez-Sánchez
- Laboratory of Psychoimmunology, National Institute of Psychiatry Ramón de la Fuente Muñíz, México City 14370, México
| | - Erika Acosta-Cruz
- Department of Biotechnology, Faculty of Chemistry, Universidad Autónoma de Coahuila, Saltillo Coahuila 25280, México
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2
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Magnuson MA, Osipovich AB. Ca 2+ signaling and metabolic stress-induced pancreatic β-cell failure. Front Endocrinol (Lausanne) 2024; 15:1412411. [PMID: 39015185 PMCID: PMC11250477 DOI: 10.3389/fendo.2024.1412411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Accepted: 06/10/2024] [Indexed: 07/18/2024] Open
Abstract
Early in the development of Type 2 diabetes (T2D), metabolic stress brought on by insulin resistance and nutrient overload causes β-cell hyperstimulation. Herein we summarize recent studies that have explored the premise that an increase in the intracellular Ca2+ concentration ([Ca2+]i), brought on by persistent metabolic stimulation of β-cells, causes β-cell dysfunction and failure by adversely affecting β-cell function, structure, and identity. This mini-review builds on several recent reviews that also describe how excess [Ca2+]i impairs β-cell function.
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Affiliation(s)
- Mark A. Magnuson
- Department of Molecular Physiology and Biophysics and Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States
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Schlünder K, Cipriano M, Zbinden A, Fuchs S, Mayr T, Schenke-Layland K, Loskill P. Microphysiological pancreas-on-chip platform with integrated sensors to model endocrine function and metabolism. LAB ON A CHIP 2024; 24:2080-2093. [PMID: 38441218 DOI: 10.1039/d3lc00838j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
Pancreatic in vitro research is of major importance to advance mechanistic understanding and development of treatment options for diseases such as diabetes mellitus. We present a thermoplastic-based microphysiological system aiming to model the complex microphysiological structure and function of the endocrine pancreas with concurrent real-time read-out capabilities. The specifically tailored platform enables self-guided trapping of single islets at defined locations: β-cells are assembled to pseudo-islets and injected into the tissue chamber using hydrostatic pressure-driven flow. The pseudo-islets can further be embedded in an ECM-like hydrogel mimicking the native microenvironment of pancreatic islets in vivo. Non-invasive real-time monitoring of the oxygen levels on-chip is realized by the integration of luminescence-based optical sensors to the platform. To monitor insulin secretion kinetics in response to glucose stimulation in a time-resolved manner, an automated cycling of different glucose conditions is implemented. The model's response to glucose stimulation can be monitored via offline analysis of insulin secretion and via specific changes in oxygen consumption due to higher metabolic activity of pseudo-islets at high glucose levels. To demonstrate applicability for drug testing, the effects of antidiabetic medications are assessed and changes in dynamic insulin secretion are observed in line with the respective mechanism of action. Finally, by integrating human pancreatic islet microtissues, we highlight the flexibility of the platform and demonstrate the preservation of long-term functionality of human endocrine pancreatic tissue.
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Affiliation(s)
- Katharina Schlünder
- Department for Microphysiological Systems, Institute of Biomedical Engineering, Eberhard Karls University Tübingen, Tübingen, Germany.
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Madalena Cipriano
- Department for Microphysiological Systems, Institute of Biomedical Engineering, Eberhard Karls University Tübingen, Tübingen, Germany.
| | - Aline Zbinden
- Department for Medical Technologies and Regenerative Medicine, Institute of Biomedical Engineering, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Stefanie Fuchs
- Institute for Analytical Chemistry and Food Chemistry, Graz University of Technology, Graz, Austria
| | - Torsten Mayr
- Institute for Analytical Chemistry and Food Chemistry, Graz University of Technology, Graz, Austria
| | - Katja Schenke-Layland
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
- Department for Medical Technologies and Regenerative Medicine, Institute of Biomedical Engineering, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Peter Loskill
- Department for Microphysiological Systems, Institute of Biomedical Engineering, Eberhard Karls University Tübingen, Tübingen, Germany.
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
- 3R-Center for In vitro Models and Alternatives to Animal Testing, Eberhard Karls University Tübingen, Tübingen, Germany
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4
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Umar AH, Ratnadewi D, Rafi M, Sulistyaningsih YC, Hamim H, Kusuma WA. Drug candidates and potential targets of Curculigo spp. compounds for treating diabetes mellitus based on network pharmacology, molecular docking and molecular dynamics simulation. J Biomol Struct Dyn 2023; 41:8544-8560. [PMID: 36300505 DOI: 10.1080/07391102.2022.2135597] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 10/08/2022] [Indexed: 10/31/2022]
Abstract
Curculigo spp. is a herb that is commonly used in Indonesia to treat diabetes mellitus (DM) . The main active components of Curculigo spp. were identified through our previous metabolomic study and online database platform. However, the biological mechanisms underlying Curculigo spp. activity in treating DM remain unclear. Therefore, in this study, a network pharmacology was used to explore the active compounds of Curculigo spp. and their potential molecular mechanisms for treating DM. Oral bioavailability and drug-likeness from the compounds of Curculigo spp. were screened using Lipinski's rule of five, BBB, HIA + and Caco-2 permeability criteria. A network of compound-target-disease-pathway was then constructed using Cytoscape. The highest degree compounds and targets were then confirmed by molecular docking and molecular dynamics (MD) simulations. The human body can absorb 33 compounds derived from Curculigo spp. In addition, 58 nodes and 62 edges generated a network analysis with the DM target. The highest degree of the compound-target-disease pathway was for orcinol glucoside, AKR1B1, autoimmune diabetes, bile acid and bile salt metabolism. Furthermore, the computational docking method on Curculigo spp. compounds with the highest degree revealed that orcinol glucoside interacted with PTPN1 through a hydrogen bond and resulted in a binding energy of -7.2 kcal mol-1. Through hydrogen bonds, orcinol glucoside in PTPN1 regulates multiple signaling pathways via the adherens junction pathway, which may play a therapeutic role in DM (type 2 diabetes: obesity). In addition, MD simulation confirmed that orcinol glucoside, is suitable for DM treatment by interacting with PTPN1.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Abdul Halim Umar
- Division of Pharmaceutical Biology, College of Pharmaceutical Sciences Makassar (Sekolah Tinggi Ilmu Farmasi Makassar), Makassar, Indonesia
| | - Diah Ratnadewi
- Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University, Bogor, Indonesia
| | - Mohamad Rafi
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, IPB University, Bogor, Indonesia
| | | | - Hamim Hamim
- Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University, Bogor, Indonesia
| | - Wisnu Ananta Kusuma
- Department of Computer Science, Faculty of Mathematics and Natural Sciences, IPB University, Bogor, Indonesia
- Tropical Biopharmaca Research Center, IPB University, Bogor, Indonesia
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Calamita G, Delporte C. Insights into the Function of Aquaporins in Gastrointestinal Fluid Absorption and Secretion in Health and Disease. Cells 2023; 12:2170. [PMID: 37681902 PMCID: PMC10486417 DOI: 10.3390/cells12172170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 08/16/2023] [Accepted: 08/17/2023] [Indexed: 09/09/2023] Open
Abstract
Aquaporins (AQPs), transmembrane proteins permeable to water, are involved in gastrointestinal secretion. The secretory products of the glands are delivered either to some organ cavities for exocrine glands or to the bloodstream for endocrine glands. The main secretory glands being part of the gastrointestinal system are salivary glands, gastric glands, duodenal Brunner's gland, liver, bile ducts, gallbladder, intestinal goblet cells, exocrine and endocrine pancreas. Due to their expression in gastrointestinal exocrine and endocrine glands, AQPs fulfill important roles in the secretion of various fluids involved in food handling. This review summarizes the contribution of AQPs in physiological and pathophysiological stages related to gastrointestinal secretion.
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Affiliation(s)
- Giuseppe Calamita
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy;
| | - Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Faculty of Medicine, Université Libre de Bruxelles, 1070 Brussels, Belgium
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Chen Y, Yao L, Zhao S, Xu M, Ren S, Xie L, Liu L, Wang Y. The oxidative aging model integrated various risk factors in type 2 diabetes mellitus at system level. Front Endocrinol (Lausanne) 2023; 14:1196293. [PMID: 37293508 PMCID: PMC10244788 DOI: 10.3389/fendo.2023.1196293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 05/10/2023] [Indexed: 06/10/2023] Open
Abstract
Background Type 2 diabetes mellitus (T2DM) is a chronic endocrine metabolic disease caused by insulin dysregulation. Studies have shown that aging-related oxidative stress (as "oxidative aging") play a critical role in the onset and progression of T2DM, by leading to an energy metabolism imbalance. However, the precise mechanisms through which oxidative aging lead to T2DM are yet to be fully comprehended. Thus, it is urgent to integrate the underlying mechanisms between oxidative aging and T2DM, where meaningful prediction models based on relative profiles are needed. Methods First, machine learning was used to build the aging model and disease model. Next, an integrated oxidative aging model was employed to identify crucial oxidative aging risk factors. Finally, a series of bioinformatic analyses (including network, enrichment, sensitivity, and pan-cancer analyses) were used to explore potential mechanisms underlying oxidative aging and T2DM. Results The study revealed a close relationship between oxidative aging and T2DM. Our results indicate that nutritional metabolism, inflammation response, mitochondrial function, and protein homeostasis are key factors involved in the interplay between oxidative aging and T2DM, even indicating key indices across different cancer types. Therefore, various risk factors in T2DM were integrated, and the theories of oxi-inflamm-aging and cellular senescence were also confirmed. Conclusion In sum, our study successfully integrated the underlying mechanisms linking oxidative aging and T2DM through a series of computational methodologies.
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Affiliation(s)
- Yao Chen
- Department of Biomedical Engineering, School of Intelligent Medicine, China Medical University, Shenyang, Liaoning, China
| | - Lilin Yao
- Department of Biomedical Engineering, School of Intelligent Medicine, China Medical University, Shenyang, Liaoning, China
| | - Shuheng Zhao
- Department of Biomedical Engineering, School of Intelligent Medicine, China Medical University, Shenyang, Liaoning, China
| | - Mengchu Xu
- Department of Biomedical Engineering, School of Intelligent Medicine, China Medical University, Shenyang, Liaoning, China
| | - Siwei Ren
- Department of Biomedical Engineering, School of Intelligent Medicine, China Medical University, Shenyang, Liaoning, China
| | - Lu Xie
- Shanghai-MOST Key Laboratory of Health and Disease Genomics & Institute for Genome and Bioinformatics, Shanghai Institute for Biomedical and Pharmaceutical Technologies, Shanghai, China
| | - Lei Liu
- Intelligent Medicine Institute, Fudan University, Shanghai, China
| | - Yin Wang
- Department of Biomedical Engineering, School of Intelligent Medicine, China Medical University, Shenyang, Liaoning, China
- Key Laboratory of GI Cancer Etiology and Prevention in Liaoning Province, The First Hospital of China Medical University, Shenyang, China
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Kuwabara R, Qin T, Alberto Llacua L, Hu S, Boekschoten MV, de Haan BJ, Smink AM, de Vos P. Extracellular matrix inclusion in immunoisolating alginate-based microcapsules promotes longevity, reduces fibrosis, and supports function of islet allografts in vivo. Acta Biomater 2023; 158:151-162. [PMID: 36610609 DOI: 10.1016/j.actbio.2022.12.068] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/14/2022] [Accepted: 12/28/2022] [Indexed: 01/06/2023]
Abstract
Immunoisolation of pancreatic-islets in alginate-microcapsules is applied to treat diabetes. However, long-term islet function is limited, which might be due to damaged and lack of contact with pancreatic extracellular matrix (ECM) components. Herein we investigated the impact of collagen IV combined with laminin sequences, either RGD, LRE, or PDSGR, on graft-survival of microencapsulated bioluminescent islets in vivo. Collagen IV with RGD had the most pronounced effect. It enhanced after 8-week implantation in immune-incompetent mice the bioluminescence of allogeneic islets by 3.2-fold, oxygen consumption rate by 14.3-fold and glucose-induced insulin release by 9.6-fold. Transcriptomics demonstrated that ECM enhanced canonical pathways involving insulin-secretion and that it suppressed pathways related to inflammation and hypoxic stress. Also, 5.8-fold fewer capsules were affected by fibrosis. In a subsequent longevity study in immune-competent mice, microencapsulated allografts containing collagen IV and RGD had a 2.4-fold higher functionality in the first week after implantation and remained at least 2.1-fold higher during the study. Islets in microcapsules containing collagen IV and RGD survived 211 ± 24.1 days while controls survived 125 ± 19.7 days. Our findings provide in vivo evidence for the efficacy of supplementing immunoisolating devices with specific ECM components to enhance functionality and longevity of islet-grafts in vivo. STATEMENT OF SIGNIFICANCE: Limitations in duration of survival of immunoisolated pancreatic islet grafts is a major obstacle for application of the technology to treat diabetes. Accumulating evidence supports that incorporation of extracellular matrix (ECM) molecules in the capsules enhances longevity of pancreatic islets. After selection of the most efficacious laminin sequence in vitro, we show in vivo that inclusion of collagen IV and RGD in alginate-based microcapsules enhances survival, insulin secretion function, and mitochondrial function. It also suppresses fibrosis by lowering proinflammatory cytokines secretion. Moreover, transcriptomic analysis shows that ECM-inclusion promotes insulin-secretion related pathways and attenuates inflammation and hypoxic stress related pathways in islets. We show that inclusion of ECM in immunoisolating devices is a promising strategy to promote long-term survival of islet-grafts.
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Affiliation(s)
- Rei Kuwabara
- Section Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, and University Medical Center Groningen, Hanzeplein 1, EA 11, Groningen 9713 GZ, the Netherlands; Department of Biomaterials, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Tian Qin
- Section Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, and University Medical Center Groningen, Hanzeplein 1, EA 11, Groningen 9713 GZ, the Netherlands.
| | - L Alberto Llacua
- Section Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, and University Medical Center Groningen, Hanzeplein 1, EA 11, Groningen 9713 GZ, the Netherlands
| | - Shuxian Hu
- Section Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, and University Medical Center Groningen, Hanzeplein 1, EA 11, Groningen 9713 GZ, the Netherlands
| | - Mark V Boekschoten
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, Wageningen 6708 WE, the Netherlands
| | - Bart J de Haan
- Section Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, and University Medical Center Groningen, Hanzeplein 1, EA 11, Groningen 9713 GZ, the Netherlands
| | - Alexandra M Smink
- Section Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, and University Medical Center Groningen, Hanzeplein 1, EA 11, Groningen 9713 GZ, the Netherlands
| | - Paul de Vos
- Section Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, and University Medical Center Groningen, Hanzeplein 1, EA 11, Groningen 9713 GZ, the Netherlands
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Wang H, Yuan YC, Chang C, Izumi T, Wang HH, Yang JK. The signaling protein GIV/Girdin mediates the Nephrin-dependent insulin secretion of pancreatic islet β cells in response to high glucose. J Biol Chem 2023; 299:103045. [PMID: 36822326 PMCID: PMC10040812 DOI: 10.1016/j.jbc.2023.103045] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 02/10/2023] [Accepted: 02/12/2023] [Indexed: 02/23/2023] Open
Abstract
Glucose-stimulated insulin secretion of pancreatic β cells is essential in maintaining glucose homeostasis. Recent evidence suggests that the Nephrin-mediated intercellular junction between β cells is implicated in the regulation of insulin secretion. However, the underlying mechanisms are only partially characterized. Herein we report that GIV is a signaling mediator coordinating glucose-stimulated Nephrin phosphorylation and endocytosis with insulin secretion. We demonstrate that GIV is expressed in mouse islets and cultured β cells. The loss of function study suggests that GIV is essential for the second phase of glucose-stimulated insulin secretion. Next, we demonstrate that GIV mediates the high glucose-stimulated tyrosine phosphorylation of GIV and Nephrin by recruiting Src kinase, which leads to the endocytosis of Nephrin. Subsequently, the glucose-induced GIV/Nephrin/Src signaling events trigger downstream Akt phosphorylation, which activates Rac1-mediated cytoskeleton reorganization, allowing insulin secretory granules to access the plasma membrane for the second-phase secretion. Finally, we found that GIV is downregulated in the islets isolated from diabetic mice, and rescue of GIV ameliorates the β-cell dysfunction to restore the glucose-stimulated insulin secretion. We conclude that the GIV/Nephrin/Akt signaling axis is vital to regulate glucose-stimulated insulin secretion. This mechanism might be further targeted for therapeutic intervention of diabetic mellitus.
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Affiliation(s)
- Hao Wang
- Beijing Key Laboratory of Diabetes Research and Care, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
| | - Ying-Chao Yuan
- Beijing Key Laboratory of Diabetes Research and Care, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Cong Chang
- College of Biology, Hunan University, Changsha, Hunan, China; Hunan Food and Drug Vocational College, Changsha, Hunan, China
| | - Tetsuro Izumi
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
| | - Hong-Hui Wang
- College of Biology, Hunan University, Changsha, Hunan, China.
| | - Jin-Kui Yang
- Beijing Key Laboratory of Diabetes Research and Care, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
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Cryo-EM structure supports a role of AQP7 as a junction protein. Nat Commun 2023; 14:600. [PMID: 36737436 PMCID: PMC9898259 DOI: 10.1038/s41467-023-36272-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 01/23/2023] [Indexed: 02/05/2023] Open
Abstract
Aquaglyceroporin 7 (AQP7) facilitates glycerol flux across the plasma membrane with a critical physiological role linked to metabolism, obesity, and associated diseases. Here, we present the single-particle cryo-EM structure of AQP7 determined at 2.55 Å resolution adopting two adhering tetramers, stabilized by extracellularly exposed loops, in a configuration like that of the well-characterized interaction of AQP0 tetramers. The central pore, in-between the four monomers, displays well-defined densities restricted by two leucine filters. Gas chromatography mass spectrometry (GC/MS) results show that the AQP7 sample contains glycerol 3-phosphate (Gro3P), which is compatible with the identified features in the central pore. AQP7 is shown to be highly expressed in human pancreatic α- and β- cells suggesting that the identified AQP7 octamer assembly, in addition to its function as glycerol channel, may serve as junction proteins within the endocrine pancreas.
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Mighty J, Rubio-Navarro A, Shi C, Zhou J, Flores-Bellver M, Heissel S, Onwumere O, Einbond L, Gharbaran R, Casper DS, Benito-Martin A, Redenti S. Extracellular vesicles of human diabetic retinopathy retinal tissue and urine of diabetic retinopathy patients are enriched for the junction plakoglo bin protein. Front Endocrinol (Lausanne) 2023; 13:1077644. [PMID: 36686464 PMCID: PMC9854122 DOI: 10.3389/fendo.2022.1077644] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 11/28/2022] [Indexed: 01/07/2023] Open
Abstract
Introduction Diabetic Retinopathy (DR) is a potentially blinding retinal disorder that develops through the pathogenesis of diabetes. The lack of disease predictors implies a poor prognosis with frequent irreversible retinal damage and vision loss. Extracellular Vesicles (EVs) present a novel opportunity for pre-symptomatic disease diagnosis and prognosis, both severely limited in DR. All biological fluids contain EVs, which are currently being studied as disease biomarkers. EV proteins derived from urine have emerged as potential noninvasive biomarkers. Methods In this study, we isolated EVs from DR retinal tissue explants and from DR patients' urine, and characterized the vesicles, finding differences in particle number and size. Next, we performed proteomic analysis on human explanted DR retinal tissue conditioned media, DR retinal EVs and DR urinary EVs and compared to normal human retinal tissue, retinal EVs, and urinary EVs, respectively. Results Our system biology analysis of DR tissue and EV expression profiles revealed biological pathways related to cell-to-cell junctions, vesicle biology, and degranulation processes. Junction Plakoglobin (JUP), detected in DR tissue-derived EVs and DR urinary EVs, but not in controls, was revealed to be a central node in many identified pathogenic pathways. Proteomic results were validated by western blot. Urinary EVs obtained from healthy donors and diabetic patient without DR did not contain JUP. Conclusion The absence of JUP in healthy urinary EVs provide the basis for development of a novel Diabetic Retinopathy biomarker, potentially facilitating diagnosis.
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Affiliation(s)
- Jason Mighty
- Lehman College, City University of New York, Bronx, NY, United States
- Biology Doctoral Program, The Graduate School and University Center, City University of New York, New York, NY, United States
| | - Alfonso Rubio-Navarro
- Weill Center for Metabolic Health, Cardiovascular Research Institute, Division of Cardiology, Department of Medicine, Weill Cornell Medicine, New York, NY, United States
- Instituto de Investigación Biosanitaria ibs GRANADA, University Hospitals of Granada-University of Granada, Granada, Spain
- Excellence Research Unit “Modeling Nature” (MNat), University of Granada, Granada, Spain
| | - Cui Shi
- Biology Doctoral Program, The Graduate School and University Center, City University of New York, New York, NY, United States
| | - Jing Zhou
- Lehman College, City University of New York, Bronx, NY, United States
- Biology Doctoral Program, The Graduate School and University Center, City University of New York, New York, NY, United States
| | - Miguel Flores-Bellver
- CellSight Ocular Stem Cell and Regeneration Program, Department of Ophthalmology, Sue Anschutz- Rodgers Eye Center, University of Colorado, Aurora, CO, United States
| | - Søren Heissel
- Proteomics Resource Center, The Rockefeller University, New York, NY, United States
| | - Onyekwere Onwumere
- Lehman College, City University of New York, Bronx, NY, United States
- Biology Doctoral Program, The Graduate School and University Center, City University of New York, New York, NY, United States
| | - Linda Einbond
- Lehman College, City University of New York, Bronx, NY, United States
| | | | - Daniel S. Casper
- Department of Ophthalmology, Columbia University Vagelos College of Physicians & Surgeons Naomi Berrie Diabetes Center, New York, NY, United States
| | - Alberto Benito-Martin
- Lehman College, City University of New York, Bronx, NY, United States
- Universidad Alfonso X El Sabio, Facultad de Medicina. Unidad de Investigación Biomédica, Madrid, Spain
| | - Stephen Redenti
- Lehman College, City University of New York, Bronx, NY, United States
- Biology Doctoral Program, The Graduate School and University Center, City University of New York, New York, NY, United States
- Department of Ophthalmology, Columbia University Vagelos College of Physicians & Surgeons Naomi Berrie Diabetes Center, New York, NY, United States
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11
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Desmoglein-2 is important for islet function and β-cell survival. Cell Death Dis 2022; 13:911. [PMID: 36309486 PMCID: PMC9617887 DOI: 10.1038/s41419-022-05326-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 10/02/2022] [Accepted: 10/06/2022] [Indexed: 12/01/2022]
Abstract
Type 1 diabetes is a complex disease characterized by the lack of endogenous insulin secreted from the pancreatic β-cells. Although β-cell targeted autoimmune processes and β-cell dysfunction are known to occur in type 1 diabetes, a complete understanding of the cell-to-cell interactions that support pancreatic function is still lacking. To characterize the pancreatic endocrine compartment, we studied pancreata from healthy adult donors and investigated a single cell surface adhesion molecule, desmoglein-2 (DSG2). Genetically-modified mice lacking Dsg2 were examined for islet cell mass, insulin production, responses to glucose, susceptibility to a streptozotocin-induced mouse model of hyperglycaemia, and ability to cure diabetes in a syngeneic transplantation model. Herein, we have identified DSG2 as a previously unrecognized adhesion molecule that supports β-cells. Furthermore, we reveal that DSG2 is within the top 10 percent of all genes expressed by human pancreatic islets and is expressed by the insulin-producing β-cells but not the somatostatin-producing δ-cells. In a Dsg2 loss-of-function mice (Dsg2lo/lo), we observed a significant reduction in the number of pancreatic islets and islet size, and consequently, there was less total insulin content per islet cluster. Dsg2lo/lo mice also exhibited a reduction in blood vessel barrier integrity, an increased incidence of streptozotocin-induced diabetes, and islets isolated from Dsg2lo/lo mice were more susceptible to cytokine-induced β-cell apoptosis. Following transplantation into diabetic mice, islets isolated from Dsg2lo/lo mice were less effective than their wildtype counterparts at curing diabetes. In vitro assays using the Beta-TC-6 murine β-cell line suggest that DSG2 supports the actin cytoskeleton as well as the release of cytokines and chemokines. Taken together, our study suggests that DSG2 is an under-appreciated regulator of β-cell function in pancreatic islets and that a better understanding of this adhesion molecule may provide new opportunities to combat type 1 diabetes.
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12
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Dissanayake WC, Shepherd PR. β-cells retain a pool of insulin-containing secretory vesicles regulated by adherens junctions and the cadherin binding protein p120 catenin. J Biol Chem 2022; 298:102240. [PMID: 35809641 PMCID: PMC9358467 DOI: 10.1016/j.jbc.2022.102240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/16/2022] [Accepted: 06/17/2022] [Indexed: 11/03/2022] Open
Abstract
The β-cells of the islets of Langerhans are the sole producers of insulin in the human body. In response to rising glucose levels, insulin-containing vesicles inside β-cells fuse with the plasma membrane and release their cargo. However, the mechanisms regulating this process are only partly understood. Previous evidence indicated reductions in α-catenin elevate insulin release, while reductions in β-catenin decrease insulin release. α- and β-catenin contribute to cellular regulation in a range of ways but one is as members of the adherens junction complex and these contribute to the development of cell polarity in b-cells. Therefore, we investigated the effects of adherens junctions on insulin release. We show in INS-1E β-cells knockdown of either E- or N-cadherin had only small effects on insulin secretion, but simultaneous knockout of both cadherins resulted in a significant increase in basal insulin release to the same level as glucose-stimulated release. This double knockdown also significantly attenuated levels of p120 catenin, a cadherin binding partner involved in regulating cadherin turnover. Conversely, reducing p120 catenin levels with siRNA destabilized both E- and N-cadherin, and this was also associated with an increase in levels of insulin secreted from INS-1E cells. Furthermore, there were also changes in these cells consistent with higher insulin release, namely reductions in levels of F-actin and increased intracellular free Ca2+ levels in response to KCl-induced membrane depolarization. Taken together, these data provide evidence that adherens junctions play important roles in retaining a pool of insulin secretory vesicles within the cell and establish a role for p120 catenin in regulating this process.
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Affiliation(s)
- Waruni C Dissanayake
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Peter R Shepherd
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
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13
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Wang D, Guo Y, Zhu J, Liu F, Xue Y, Huang Y, Zhu B, Wu D, Pan H, Gong T, Lu Y, Yang Y, Wang Z. Hyaluronic acid methacrylate/pancreatic extracellular matrix as a potential 3D printing bioink for constructing islet organoids. Acta Biomater 2022:S1742-7061(22)00375-0. [PMID: 35803504 DOI: 10.1016/j.actbio.2022.06.036] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 11/01/2022]
Abstract
Islet transplantation has poor long-term efficacy because of the lack of extracellular matrix support and neovascularization; this limits its wide application in diabetes research. In this study, we develop a 3D-printed islet organoid by combining a pancreatic extracellular matrix (pECM) and hyaluronic acid methacrylate (HAMA) as specific bioinks. The HAMA/pECM hydrogel was validated in vitro to maintain islet cell adhesion and morphology through the Rac1/ROCK/MLCK signaling pathway, which helps improve islet function and activity. Further, in vivo experiments confirmed that the 3D-printed islet-encapsulated HAMA/pECM hydrogel increases insulin levels in diabetic mice, maintains blood glucose levels within a normal range for 90 days, and rapidly secretes insulin in response to blood glucose stimulation. In addition, the HAMA/pECM hydrogel can facilitate the attachment and growth of new blood vessels and increase the density of new vessels. Meanwhile, the designed 3D-printed structure was conducive to the formation of vascular networks and it promoted the construction of 3D-printed islet organoids. In conclusion, our experiments optimized the HAMA/pECM bioink composition and 3D-printed structure of islet organoids with promising therapeutic effects compared with the HAMA hydrogel group that can be potentially used in clinical applications to improve the effectiveness and safety of islet transplantation in vivo. STATEMENT OF SIGNIFICANCE: The extraction process of pancreatic islets can easily cause damage to the extracellular matrix and vascular system, resulting in poor islet transplantation efficiency. We developed a new tissue-specific bioink by combining pancreatic extracellular matrix (pECM) and hyaluronic acid methacrylate (HAMA). The islet organoids constructed by 3D printing can mimic the microenvironment of the pancreas and maintain islet cell adhesion and morphology through the Rac1/ROCK/MLCK signaling pathway, thereby improving islet function and activity. In addition, the 3D-printed structures we designed are favorable for the formation of new blood vessel networks, bringing hope for the long-term efficacy of islet transplantation.
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Affiliation(s)
- Dongzhi Wang
- Department of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Nantong University, Nantong, 226006, China; Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong, 226006, China
| | - Yibing Guo
- Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong, 226006, China
| | - Jiacheng Zhu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226007, China
| | - Fang Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226007, China
| | - Yan Xue
- Department of Internal Medicine, Nantong Health College of Jiangsu Province, Nantong, 226010, China
| | - Yan Huang
- Department of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Nantong University, Nantong, 226006, China
| | - Biwen Zhu
- Department of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Nantong University, Nantong, 226006, China; Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong, 226006, China
| | - Di Wu
- Department of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Nantong University, Nantong, 226006, China; Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong, 226006, China
| | - Haopeng Pan
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226007, China
| | - Tiancheng Gong
- Department of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Nantong University, Nantong, 226006, China; Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong, 226006, China
| | - Yuhua Lu
- Department of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Nantong University, Nantong, 226006, China.
| | - Yumin Yang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226007, China.
| | - Zhiwei Wang
- Department of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Nantong University, Nantong, 226006, China.
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14
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Collares-Buzato CB, Carvalho CP. Is type 2 diabetes mellitus another intercellular junction-related disorder? Exp Biol Med (Maywood) 2022; 247:743-755. [PMID: 35466731 DOI: 10.1177/15353702221090464] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Type 2 diabetes mellitus (T2D) is nowadays a worldwide epidemic and has become a major challenge for health systems around the world. It is a multifactorial disorder, characterized by a chronic state of hyperglycemia caused by defects in the production as well as in the peripheral action of insulin. This minireview highlights the experimental and clinical evidence that supports the novel idea that intercellular junctions (IJs)-mediated cell-cell contacts play a role in the pathogenesis of T2D. It focuses on IJs repercussion for endocrine pancreas, intestinal barrier, and kidney dysfunctions that contribute to the onset and evolution of this metabolic disorder.
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Affiliation(s)
- Carla B Collares-Buzato
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, CEP 13083-970, Brazil
| | - Carolina Pf Carvalho
- Department of Biosciences, Federal University of São Paulo (UNIFESP), Santos, SP, CEP 11015-020, Brazil
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15
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Martinez C, Maschio DA, de Fontes CC, Vanzela EC, Benfato ID, Gazarini ML, Carneiro EM, de Oliveira CA, Collares-Buzato CB, de F. Carvalho CP. EARLY DECREASE IN CX36 IS ASSOCIATED WITH INCREASED CELL ADHESION MOLECULES (CAMs) JUNCTIONAL CONTENT IN MOUSE PANCREATIC ISLETS AFTER SHORT-TERM HIGH-FAT DIET FEEDING. Ann Anat 2022; 241:151891. [DOI: 10.1016/j.aanat.2022.151891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 11/29/2022]
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16
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Title AC, Silva PN, Godbersen S, Hasenöhrl L, Stoffel M. The miR-200-Zeb1 axis regulates key aspects of β-cell function and survival in vivo. Mol Metab 2021; 53:101267. [PMID: 34116231 PMCID: PMC8258987 DOI: 10.1016/j.molmet.2021.101267] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/24/2021] [Accepted: 06/03/2021] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE The miR-200-Zeb1 axis regulates the epithelial-to-mesenchymal transition (EMT), differentiation, and resistance to apoptosis. A better understanding of these processes in diabetes is highly relevant, as β-cell dedifferentiation and apoptosis contribute to the loss of functional β-cell mass and diabetes progression. Furthermore, EMT promotes the loss of β-cell identity in the in vitro expansion of human islets. Though the miR-200 family has previously been identified as a regulator of β-cell apoptosis in vivo, studies focusing on Zeb1 are lacking. The aim of this study was thus to investigate the role of Zeb1 in β-cell function and survival in vivo. METHODS miR-200 and Zeb1 are involved in a double-negative feedback loop. We characterized a mouse model in which miR-200 binding sites in the Zeb1 3'UTR are mutated (Zeb1200), leading to a physiologically relevant upregulation of Zeb1 mRNA expression. The role of Zeb1 was investigated in this model via metabolic tests and analysis of isolated islets. Further insights into the distinct contributions of the miR-200 and Zeb1 branches of the feedback loop were obtained by crossing the Zeb1200 allele into a background of miR-141-200c overexpression. RESULTS Mild Zeb1 derepression in vivo led to broad transcriptional changes in islets affecting β-cell identity, EMT, insulin secretion, cell-cell junctions, the unfolded protein response (UPR), and the response to ER stress. The aggregation and insulin secretion of dissociated islets of mice homozygous for the Zeb1200 mutation (Zeb1200M) were impaired, and Zeb1200M islets were resistant to thapsigargin-induced ER stress ex vivo. Zeb1200M mice had increased circulating proinsulin levels but no overt metabolic phenotype, reflecting the strong compensatory ability of islets to maintain glucose homeostasis. CONCLUSIONS This study signifies the importance of the miR-200-Zeb1 axis in regulating key aspects of β-cell function and survival. A better understanding of this axis is highly relevant in developing therapeutic strategies for inducing β-cell redifferentiation and maintaining β-cell identity in in vitro islet expansion.
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Affiliation(s)
- Alexandra C Title
- Institute of Molecular Health Sciences (IMHS), ETH Zürich, Otto-Stern-Weg 7, 8093, Zürich, Switzerland; Competence Center Personalized Medicine, ETH Zürich, Voltastrasse 24, 8044, Zürich, Switzerland
| | - Pamuditha N Silva
- Institute of Molecular Health Sciences (IMHS), ETH Zürich, Otto-Stern-Weg 7, 8093, Zürich, Switzerland
| | - Svenja Godbersen
- Institute of Molecular Health Sciences (IMHS), ETH Zürich, Otto-Stern-Weg 7, 8093, Zürich, Switzerland
| | - Lynn Hasenöhrl
- Institute of Molecular Health Sciences (IMHS), ETH Zürich, Otto-Stern-Weg 7, 8093, Zürich, Switzerland
| | - Markus Stoffel
- Institute of Molecular Health Sciences (IMHS), ETH Zürich, Otto-Stern-Weg 7, 8093, Zürich, Switzerland; Competence Center Personalized Medicine, ETH Zürich, Voltastrasse 24, 8044, Zürich, Switzerland; Medical Faculty, University of Zürich, 8091, Zürich, Switzerland.
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17
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Zhu Y, Chen S, Liu W, Zhang L, Xu F, Hayashi T, Mizuno K, Hattori S, Fujisaki H, Ikejima T. Collagens I and V differently regulate the proliferation and adhesion of rat islet INS-1 cells through the integrin β1/E-cadherin/β-catenin pathway. Connect Tissue Res 2021; 62:658-670. [PMID: 33957832 DOI: 10.1080/03008207.2020.1845321] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Extracellular matrix (ECM) plays an important role in tissue repair, cell proliferation, and differentiation. Our previous study showed that collagen I and collagen V differently regulate the proliferation of rat pancreatic β cells (INS-1 cells) through opposite influences on the nuclear translocation of β-catenin. In this study, we investigated the β-catenin pathway in INS-1 cells on dishes coated with collagen I or V. We found that nuclear translocation of the transcription factor Yes-associated protein (YAP) was enhanced by collagen I and suppressed by collagen V, but had no effect on INS-1 cell proliferation. Morphologically, INS-1 cells on collagen V-coated dishes showed stronger cell-to-cell adhesion, while the cells on collagen I-coated dishes showed weaker cell-to-cell adhesion in comparison with the cells on non-coated dishes. E-cadherin played an inhibitory role in the proliferation of INS-1 cells cultured on collagen I or collagen V coated dishes via regulation of the nuclear translocation of β-catenin. Integrin β1 was enhanced with collagen I, while it was repressed with collagen V. The integrin β1 pathway positively regulated the cell proliferation. Inhibition of integrin β1 pathway restored the protein level of E-cadherin and inhibited the nuclear translocation of β-catenin in the cells on collagen I-coated dishes, but no effect was observed in the cells on collagen V-coated dishes. In conclusion, collagen I enhances the proliferation of INS-1 cells via the integrin β1 and E-cadherin/β-catenin signaling pathway. In INS-1 cells on collagen V-coated dishes, both integrin β1 and E-cadherin/β-catenin signal pathways are involved in the inhibition of proliferation.
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Affiliation(s)
- Yingying Zhu
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, China
| | - Shuaigao Chen
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, China
| | - Weiwei Liu
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, China
| | - Luxin Zhang
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, China
| | - Fanxing Xu
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, China
| | - Toshihiko Hayashi
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, China.,Department of Chemistry and Life Science, School of Advanced Engineering Kogakuin University, 2665-1, Nakanomachi Hachioji, Tokyo, 192-0015, Japan
| | - Kazunori Mizuno
- Nippi Research Institute of Biomatrix, Toride, Ibaraki 302-0017, Japan
| | - Shunji Hattori
- Nippi Research Institute of Biomatrix, Toride, Ibaraki 302-0017, Japan
| | - Hitomi Fujisaki
- Nippi Research Institute of Biomatrix, Toride, Ibaraki 302-0017, Japan
| | - Takashi Ikejima
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, China.,Key Laboratory of Computational Chemistry-Based Natural Antitumor Drug Research & Development, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, China
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18
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Kuo T, Du W, Miyachi Y, Dadi PK, Jacobson DA, Segrè D, Accili D. Antagonistic epistasis of Hnf4α and FoxO1 metabolic networks through enhancer interactions in β-cell function. Mol Metab 2021; 53:101256. [PMID: 34048961 PMCID: PMC8225970 DOI: 10.1016/j.molmet.2021.101256] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/04/2021] [Accepted: 05/12/2021] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE Genetic and acquired abnormalities contribute to pancreatic β-cell failure in diabetes. Transcription factors Hnf4α (MODY1) and FoxO1 are respective examples of these two components and act through β-cell-specific enhancers. However, their relationship is unclear. METHODS In this report, we show by genome-wide interrogation of chromatin modifications that ablation of FoxO1 in mature β-cells enriches active Hnf4α enhancers according to a HOMER analysis. RESULTS To model the functional significance of this predicted unusual enhancer utilization, we generated single and compound knockouts of FoxO1 and Hnf4α in β-cells. Single knockout of either gene impaired insulin secretion in mechanistically distinct fashions as indicated by their responses to sulfonylurea and calcium fluxes. Surprisingly, the defective β-cell secretory function of either single mutant in hyperglycemic clamps and isolated islets treated with various secretagogues was completely reversed in double mutants lacking FoxO1 and Hnf4α. Gene expression analyses revealed distinct epistatic modalities by which the two transcription factors regulate networks associated with reversal of β-cell dysfunction. An antagonistic network regulating glycolysis, including β-cell "disallowed" genes, and a synergistic network regulating protocadherins emerged as likely mediators of the functional restoration of insulin secretion. CONCLUSIONS The findings provide evidence of antagonistic epistasis as a model of gene/environment interactions in the pathogenesis of β-cell dysfunction.
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Affiliation(s)
- Taiyi Kuo
- Department of Medicine and Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, USA.
| | - Wen Du
- Department of Medicine and Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Yasutaka Miyachi
- Department of Medicine and Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Prasanna K Dadi
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - David A Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Daniel Segrè
- Department of Biology, Department of Biomedical Engineering, Department of Physics, Boston University, Boston, MA, USA
| | - Domenico Accili
- Department of Medicine and Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, USA
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19
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A role for PAK1 mediated phosphorylation of β-catenin Ser552 in the regulation of insulin secretion. Biochem J 2021; 478:1605-1615. [PMID: 33605402 DOI: 10.1042/bcj20200862] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/17/2021] [Accepted: 02/18/2021] [Indexed: 12/27/2022]
Abstract
The presence of adherens junctions and the associated protein β-catenin are requirements for the development of glucose-stimulated insulin secretion (GSIS) in β-cells. Evidence indicates that modulation of β-catenin function in response to changes in glucose levels can modulate the levels of insulin secretion from β-cells but the role of β-catenin phosphorylation in this process has not been established. We find that a Ser552Ala version of β-catenin attenuates glucose-stimulated insulin secretion indicating a functional role for Ser552 phosphorylation of β-catenin in insulin secretion. This is associated with alterations F/G actin ratio but not the transcriptional activity of β-catenin. Both glucose and GLP-1 stimulated phosphorylation of the serine 552 residue on β-catenin. We investigated the possibility that an EPAC-PAK1 pathway might be involved in this phosphorylation event. We find that reduction in PAK1 levels using siRNA attenuates both glucose and GLP-1 stimulated phosphorylation of β-catenin Ser552 and the effects of these on insulin secretion in β-cell models. Furthermore, both the EPAC inhibitor ESI-09 and the PAK1 inhibitor IPA3 do the same in both β-cell models and mouse islets. Together this identifies phosphorylation of β-catenin at Ser552 as part of a cell signalling mechanism linking nutrient and hormonal regulation of β-catenin to modulation of insulin secretory capacity of β-cells and indicates this phosphorylation event is regulated downstream of EPAC and PAK1 in β-cells.
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20
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Dwivedi PSR, Khanal P, Gaonkar VP, Rasal VP, Patil BM. Identification of PTP1B regulators from Cymbopogon citratus and its enrichment analysis for diabetes mellitus. In Silico Pharmacol 2021; 9:30. [PMID: 33928007 PMCID: PMC8039068 DOI: 10.1007/s40203-021-00088-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 03/15/2021] [Indexed: 02/07/2023] Open
Abstract
PTP1B is identified as the insulin signaling pathway downregulator; involved in pancreatic β-cell apoptosis. Further, it associates in regulating multiple pathways in diabetes mellitus; kindled us to identify the binding affinity of bioactives from Cymbopogon citratus by targeting PTP1B and identify the probably associated with it; further identifying the probable pathways involved in diabetes mellitus. In this regard, ChEBI database was used to retrieve bio-actives from C. citrates and 3D structures for the same were obtained from the PubChem database. The energy of bioactives was minimized and converted into ligand and the docking was carried using autodock 4.0 against PTP1B. Further, multiple characters of bio-actives like drug-likeness score, ADMET profile, probable adverse effects, and boiled egg model for bioavailability were also studied. Swertiajaponin was predicted for the highest drug-likeness score i.e. 0.26. However, swertiajaponin was predicted with the highest probable side effect of nephrotoxicity with pharmacological activity of 0.478. Similarly, swertiajaponin was predicted for the highest binding affinity with PTP1B with the binding energy of - 8.3 kcal/mol. Likewise, KEGG identified 80 pathways associated with PTP1B modulation in which 7 pathways were involved in diabetes mellitus in which FoxO signaling pathway was predicted to have the least false discovery rate by modulating 7 genes. Swertiajaponin could act as the potent inhibitor of PTP1B; scored highest druglikeness score but possessed minimum GIT absorptivity; further, PTP1B was identified to be linked with multiple pathways that are concerned with diabetes mellitus.
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Affiliation(s)
- Prarambh S. R. Dwivedi
- Department of Pharmacology and Toxicology, KLE College of Pharmacy Belagavi, KLE Academy of Higher Education and Research (KAHER), Belagavi, 590010 India
| | - Pukar Khanal
- Department of Pharmacology and Toxicology, KLE College of Pharmacy Belagavi, KLE Academy of Higher Education and Research (KAHER), Belagavi, 590010 India
| | - Vishakha Parab Gaonkar
- Department of Pharmacognosy and Phytochemistry, KLE College of Pharmacy Belagavi, KLE Academy of Higher Education and Research (KAHER), Belagavi, 590010 India
| | - V. P. Rasal
- Department of Pharmacology and Toxicology, KLE College of Pharmacy Belagavi, KLE Academy of Higher Education and Research (KAHER), Belagavi, 590010 India
| | - B. M. Patil
- Department of Pharmacology and Toxicology, KLE College of Pharmacy Belagavi, KLE Academy of Higher Education and Research (KAHER), Belagavi, 590010 India
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21
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Identification of Candidate Genes and Pathways Associated with Obesity-Related Traits in Canines via Gene-Set Enrichment and Pathway-Based GWAS Analysis. Animals (Basel) 2020; 10:ani10112071. [PMID: 33182249 PMCID: PMC7695335 DOI: 10.3390/ani10112071] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 11/06/2020] [Accepted: 11/06/2020] [Indexed: 02/06/2023] Open
Abstract
The present study aimed to identify causative loci and genes enriched in pathways associated with canine obesity using a genome-wide association study (GWAS). The GWAS was first performed to identify candidate single-nucleotide polymorphisms (SNPs) associated with obesity and obesity-related traits including body weight and blood sugar in 18 different breeds of 153 dogs. A total of 10 and 2 SNPs were found to be significantly (p < 3.74 × 10-7) associated with body weight and blood sugar, respectively. None of the SNPs were identified to be significantly associated with obesity trait. We subsequently followed up the GWAS analysis with gene-set enrichment and pathway analyses. A gene-set with 1057, 1409, and 1243 SNPs annotated to 449, 933 and 820 genes for obesity, body weight, and blood sugar, respectively was created by sub-setting the GWAS result at a threshold of p < 0.01 for the gene-set enrichment analysis. In total, 84 GO and 21 KEGG pathways for obesity, 114 GO and 44 KEGG pathways for blood sugar, 120 GO and 24 KEGG pathways for body weight were found to be enriched. Among the pathways and GO terms, we highlighted five enriched pathways (Wnt signaling pathway, adherens junction, pathways in cancer, axon guidance, and insulin secretion) and seven GO terms (fat cell differentiation, calcium ion binding, cytoplasm, nucleus, phospholipid transport, central nervous system development, and cell surface) that were found to be shared among all the traits. Our data provide insights into the genes and pathways associated with obesity and obesity-related traits.
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22
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Singh R, Cottle L, Loudovaris T, Xiao D, Yang P, Thomas HE, Kebede MA, Thorn P. Enhanced structure and function of human pluripotent stem cell-derived beta-cells cultured on extracellular matrix. Stem Cells Transl Med 2020; 10:492-505. [PMID: 33145960 PMCID: PMC7900592 DOI: 10.1002/sctm.20-0224] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 10/07/2020] [Accepted: 10/09/2020] [Indexed: 12/14/2022] Open
Abstract
The differentiation of human stem cells into insulin secreting beta‐like cells holds great promise to treat diabetes. Current protocols drive stem cells through stages of directed differentiation and maturation and produce cells that secrete insulin in response to glucose. Further refinements are now needed to faithfully phenocopy the responses of normal beta cells. A critical factor in normal beta cell behavior is the islet microenvironment which plays a central role in beta cell survival, proliferation, gene expression and secretion. One important influence on native cell responses is the capillary basement membrane. In adult islets, each beta cell makes a point of contact with basement membrane protein secreted by vascular endothelial cells resulting in structural and functional polarization. Interaction with basement membrane proteins triggers local activation of focal adhesions, cell orientation, and targeting of insulin secretion. This study aims to identifying the role of basement membrane proteins on the structure and function of human embryonic stem cell and induced pluripotent stem cell‐derived beta cells. Here, we show that differentiated human stem cells‐derived spheroids do contain basement membrane proteins as a diffuse web‐like structure. However, the beta‐like cells within the spheroid do not polarize in response to this basement membrane. We demonstrate that 2D culture of the differentiated beta cells on to basement membrane proteins enforces cell polarity and favorably alters glucose dependent insulin secretion.
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Affiliation(s)
- Reena Singh
- Charles Perkins Centre, Discipline of Physiology, School of Medical Sciences, University of Sydney, Camperdown, New South Wales, Australia
| | - Louise Cottle
- Charles Perkins Centre, Discipline of Physiology, School of Medical Sciences, University of Sydney, Camperdown, New South Wales, Australia
| | | | - Di Xiao
- Computational Systems Biology Group, Children's Medical Research Institute, University of Sydney, Westmead, New South Wales, Australia
| | - Pengyi Yang
- Computational Systems Biology Group, Children's Medical Research Institute, University of Sydney, Westmead, New South Wales, Australia.,Charles Perkins Centre, School of Mathematics and Statistics, University of Sydney, Sydney, New South Wales, Australia
| | - Helen E Thomas
- St Vincent's Institute, Fitzroy, Victoria, Australia.,Department of Medicine, St Vincent's Hospital, The University of Melbourne, Fitzroy, Victoria, Australia
| | - Melkam A Kebede
- Charles Perkins Centre, Discipline of Physiology, School of Medical Sciences, University of Sydney, Camperdown, New South Wales, Australia
| | - Peter Thorn
- Charles Perkins Centre, Discipline of Physiology, School of Medical Sciences, University of Sydney, Camperdown, New South Wales, Australia
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α-catenin isoforms are regulated by glucose and involved in regulating insulin secretion in rat clonal β-cell models. Biochem J 2020; 477:763-772. [PMID: 32003420 PMCID: PMC7036346 DOI: 10.1042/bcj20190832] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/29/2020] [Accepted: 01/30/2020] [Indexed: 12/19/2022]
Abstract
The recent finding that β-catenin levels play an important rate-limiting role in processes regulating insulin secretion lead us to investigate whether its binding partner α-catenin also plays a role in this process. We find that levels of both α-E-catenin and α-N-catenin are rapidly up-regulated as levels of glucose are increased in rat clonal β-cell models INS-1E and INS-832/3. Lowering in levels of either α-catenin isoform using siRNA resulted in significant increases in glucose stimulated insulin secretion (GSIS) and this effect was attenuated when β-catenin levels were lowered indicating these proteins have opposing effects on insulin release. This effect of α-catenin knockdown on GSIS was not due to increases in insulin expression but was associated with increases in calcium influx into cells. Moreover, simultaneous depletion of α-E catenin and α-N catenin decreased the actin polymerisation to a similar degree as latrunculin treatment and inhibition of ARP 2/3 mediated actin branching with CK666 attenuated the α-catenin depletion effect on GSIS. This suggests α-catenin mediated actin remodelling may be involved in the regulation of insulin secretion. Together this indicates that α-catenin and β-catenin can play opposing roles in regulating insulin secretion, with some degree of functional redundancy in roles of α-E-catenin and α-N-catenin. The finding that, at least in β-cell models, the levels of each can be regulated in the longer term by glucose also provides a potential mechanism by which sustained changes in glucose levels might impact on the magnitude of GSIS.
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Osipovich AB, Stancill JS, Cartailler JP, Dudek KD, Magnuson MA. Excitotoxicity and Overnutrition Additively Impair Metabolic Function and Identity of Pancreatic β-Cells. Diabetes 2020; 69:1476-1491. [PMID: 32332159 PMCID: PMC7809715 DOI: 10.2337/db19-1145] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 04/20/2020] [Indexed: 12/14/2022]
Abstract
A sustained increase in intracellular Ca2+ concentration (referred to hereafter as excitotoxicity), brought on by chronic metabolic stress, may contribute to pancreatic β-cell failure. To determine the additive effects of excitotoxicity and overnutrition on β-cell function and gene expression, we analyzed the impact of a high-fat diet (HFD) on Abcc8 knockout mice. Excitotoxicity caused β-cells to be more susceptible to HFD-induced impairment of glucose homeostasis, and these effects were mitigated by verapamil, a Ca2+ channel blocker. Excitotoxicity, overnutrition, and the combination of both stresses caused similar but distinct alterations in the β-cell transcriptome, including additive increases in genes associated with mitochondrial energy metabolism, fatty acid β-oxidation, and mitochondrial biogenesis and their key regulator Ppargc1a Overnutrition worsened excitotoxicity-induced mitochondrial dysfunction, increasing metabolic inflexibility and mitochondrial damage. In addition, excitotoxicity and overnutrition, individually and together, impaired both β-cell function and identity by reducing expression of genes important for insulin secretion, cell polarity, cell junction, cilia, cytoskeleton, vesicular trafficking, and regulation of β-cell epigenetic and transcriptional program. Sex had an impact on all β-cell responses, with male animals exhibiting greater metabolic stress-induced impairments than females. Together, these findings indicate that a sustained increase in intracellular Ca2+, by altering mitochondrial function and impairing β-cell identity, augments overnutrition-induced β-cell failure.
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Affiliation(s)
- Anna B Osipovich
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Vanderbilt Center for Stem Cell Biology, Vanderbilt University, Nashville, TN
| | - Jennifer S Stancill
- Vanderbilt Center for Stem Cell Biology, Vanderbilt University, Nashville, TN
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
| | | | - Karrie D Dudek
- Vanderbilt Center for Stem Cell Biology, Vanderbilt University, Nashville, TN
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
| | - Mark A Magnuson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Vanderbilt Center for Stem Cell Biology, Vanderbilt University, Nashville, TN
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
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25
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Alessandra G, Algerta M, Paola M, Carsten S, Cristina L, Paolo M, Elisa M, Gabriella T, Carla P. Shaping Pancreatic β-Cell Differentiation and Functioning: The Influence of Mechanotransduction. Cells 2020; 9:E413. [PMID: 32053947 PMCID: PMC7072458 DOI: 10.3390/cells9020413] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/29/2020] [Accepted: 02/07/2020] [Indexed: 02/08/2023] Open
Abstract
Embryonic and pluripotent stem cells hold great promise in generating β-cells for both replacing medicine and novel therapeutic discoveries in diabetes mellitus. However, their differentiation in vitro is still inefficient, and functional studies reveal that most of these β-like cells still fail to fully mirror the adult β-cell physiology. For their proper growth and functioning, β-cells require a very specific environment, the islet niche, which provides a myriad of chemical and physical signals. While the nature and effects of chemical stimuli have been widely characterized, less is known about the mechanical signals. We here review the current status of knowledge of biophysical cues provided by the niche where β-cells normally live and differentiate, and we underline the possible machinery designated for mechanotransduction in β-cells. Although the regulatory mechanisms remain poorly understood, the analysis reveals that β-cells are equipped with all mechanosensors and signaling proteins actively involved in mechanotransduction in other cell types, and they respond to mechanical cues by changing their behavior. By engineering microenvironments mirroring the biophysical niche properties it is possible to elucidate the β-cell mechanotransductive-regulatory mechanisms and to harness them for the promotion of β-cell differentiation capacity in vitro.
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Affiliation(s)
- Galli Alessandra
- Department of Excellence of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
| | - Marku Algerta
- Department of Excellence of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
| | - Marciani Paola
- Department of Excellence of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
| | - Schulte Carsten
- CIMAINA, Department of Physics, Università degli Studi di Milano, 20133 Milan, Italy
| | - Lenardi Cristina
- CIMAINA, Department of Physics, Università degli Studi di Milano, 20133 Milan, Italy
| | - Milani Paolo
- CIMAINA, Department of Physics, Università degli Studi di Milano, 20133 Milan, Italy
| | - Maffioli Elisa
- Department of Veterinary Medicine, Università degli Studi di Milano, 20133 Milan, Italy
| | - Tedeschi Gabriella
- Department of Veterinary Medicine, Università degli Studi di Milano, 20133 Milan, Italy
| | - Perego Carla
- Department of Excellence of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
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26
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Lammert E, Thorn P. The Role of the Islet Niche on Beta Cell Structure and Function. J Mol Biol 2019; 432:1407-1418. [PMID: 31711959 DOI: 10.1016/j.jmb.2019.10.032] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/25/2019] [Accepted: 10/29/2019] [Indexed: 01/15/2023]
Abstract
The islets of Langerhans or pancreatic islets are pivotal in the control of blood glucose and are complex microorgans embedded within the larger volume of the exocrine pancreas. Humans can have ~3.2 million islets [1] which, to our current knowledge, function in a similar manner to sense circulating blood glucose levels and respond with the secretion of a mix of different hormones that act to maintain glucose concentrations around a specific set point [2]. At a cellular level, the control of hormone secretion by glucose and other secretagogues is well-understood [3]. The key signal cascades have been identified and many details of the secretory process are known. However, if we shift focus from single cells and consider cells within intact islets, we do not have a comprehensive model as to how the islet environment influences cell function and how the islets work as a whole. This is important because there is overwhelming evidence that the structure and function of the individual endocrine cells are dramatically affected by the islet environment [4,5]. Uncovering the influence of this islet niche might drive future progress in treatments for Type 2 diabetes [6] and cell replacement therapies for Type 1 diabetes [7]. In this review, we focus on the insulin secreting beta cells and their interactions with the immediate environment that surrounds them including endocrine-endocrine interactions and contacts with capillaries.
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Affiliation(s)
- Eckhard Lammert
- Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany; Institute for Vascular and Islet Cell Biology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Peter Thorn
- Charles Perkins Centre, School of Medical Sciences, University of Sydney, Camperdown, NSW 2006, Australia.
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27
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McEwen HJL, Cognard E, Ladyman SR, Khant-Aung Z, Tups A, Shepherd PR, Grattan DR. Feeding and GLP-1 receptor activation stabilize β-catenin in specific hypothalamic nuclei in male rats. J Neuroendocrinol 2018; 30:e12607. [PMID: 29752762 DOI: 10.1111/jne.12607] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 05/03/2018] [Indexed: 12/21/2022]
Abstract
β-catenin is a multifunctional protein that can act in the canonical Wnt/β-catenin pathway to regulate gene expression but can also bind to cadherin proteins in adherens junctions where it plays a key role in regulating cytoskeleton linked with these junctions. Recently, evidence has been presented indicating an essential role for β-catenin in regulating trafficking of insulin vesicles in β-cells and showing that changes in nutrient levels rapidly alter levels of β-catenin in these cells. Given the importance of neuroendocrine hormone secretion in the regulation of whole body glucose homeostasis, the objective of this study was to investigate whether β-catenin signalling is regulated in the hypothalamus during the normal physiological response to food intake. Rats were subjected to a fasting/re-feeding paradigm, and then samples collected at specific timepoints for analysis of β-catenin expression by immunohistochemistry and Western blotting. Changes in gene expression were assessed by RT-qPCR. Using immunohistochemistry, feeding acutely increased detectable cytoplasmic levels of β-catenin ('stabilized β-catenin') in neurons in specific regions of the hypothalamus involved in metabolic regulation, including the arcuate, dorsomedial and paraventricular nuclei of the hypothalamus. Feeding-induced elevations in β-catenin in these nuclei were associated with increased transcription of several genes that are known to be responsive to Wnt/β-catenin signalling. The effect of feeding was mimicked by administration of the GLP-1 agonist exendin-4, and was characterized by cAMP-dependent phosphorylation of β-catenin at serine residues 552 and 675. The data suggest that β-catenin/TCF signalling is involved in metabolic sensing in the hypothalamus. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Hayden J L McEwen
- Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
- Department of Anatomy, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, New Zealand
| | - Emmanuelle Cognard
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - Sharon R Ladyman
- Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
- Department of Anatomy, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, New Zealand
| | - Zin Khant-Aung
- Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Alexander Tups
- Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, New Zealand
- Department of Physiology, University of Otago, Dunedin, New Zealand
| | - Peter R Shepherd
- Maurice Wilkins Centre for Molecular Biodiscovery, New Zealand
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - David R Grattan
- Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
- Department of Anatomy, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, New Zealand
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