scholarly journals Glucolipotoxicity-induced Mig6 desensitizes EGFR signaling and promotes pancreatic beta cell death

2020 ◽  
Author(s):  
Yi-Chun Chen ◽  
Andrew J. Lutkewitte ◽  
Halesha D. Basavarajappa ◽  
Patrick T. Fueger
Keyword(s):  
Cell Death ◽  
Growth Factor ◽  
Beta Cell ◽  
Cell Survival ◽  
Beta Cells ◽  
Cell Mass ◽  
Signaling Cascades ◽  
Egfr Signaling ◽  
Mitogenic Signaling ◽  
Beta Cell Death

ABSTRACTA loss of functional beta cell mass is a final etiological event in the development of frank type 2 diabetes (T2D). To preserve or expand beta cells and therefore treat/prevent T2D, growth factors have been considered therapeutically but have largely failed to achieve robust clinical success. The molecular mechanisms preventing the activation of mitogenic signaling pathways from maintaining functional beta cell mass during the development of T2D remain unknown. We speculated that endogenous negative effectors of mitogenic signaling cascades impede beta cell survival/expansion. Thus, we tested the hypothesis that a stress-inducible epidermal growth factor receptor (EGFR) inhibitor, Mitogen-inducible gene 6 (Mig6), regulates beta cell fate in a T2D milieu. To this end, we determined that: 1) glucolipotoxicity (GLT) induces Mig6, thereby blunting EGFR signaling cascades, and 2) Mig6 mediates molecular events regulating beta cell survival/death. We discovered that GLT impairs EGFR activation, and Mig6 is elevated in human islets from T2D donors as well as GLT-treated rodent islets and 832/13 INS-1 beta cells. Mig6 is essential for GLT-induced EGFR desensitization, as Mig6 suppression rescued the GLT-impaired EGFR and ERK1/2 activation. Further, Mig6 mediated EGFR but not insulin-like growth factor-1 receptor nor hepatocyte growth factor receptor activity in beta cells. Finally, we identified that elevated Mig6 augmented beta cell apoptosis, as Mig6 suppression reduced apoptosis during GLT. In conclusion, we established that T2D and GLT induce Mig6 in pancreatic beta cells. The elevated Mig6 desensitizes EGFR signaling and induces beta cell death. Our findings suggest that Mig6 could be a novel therapeutic target for T2D, as blocking Mig6 could possibly enhance mitogenic signaling cascades in a diabetic milieu to promote beta cell survival and prevent beta cell death.

scholarly journals The Class I Histone Deacetylase Inhibitor MS-275 Prevents Pancreatic Beta Cell Death Induced by Palmitate

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Valérie Plaisance ◽  
Laure Rolland ◽  
Valéry Gmyr ◽  
Jean-Sébastien Annicotte ◽  
Julie Kerr-Conte ◽  
...  
Keyword(s):  
Cell Death ◽  
Beta Cell ◽  
Er Stress ◽  
Beta Cells ◽  
Pancreatic Beta Cell ◽  
Cell Mass ◽  
Beta Cell Mass ◽  
Activating Transcription Factor 3 ◽  
Beta Cell Death ◽  
Stress Markers

Elevation of the dietary saturated fatty acid palmitate contributes to the reduction of functional beta cell mass in the pathogenesis of type 2 diabetes. The diabetogenic effect of palmitate is achieved by increasing beta cell death through induction of the endoplasmic reticulum (ER) stress markers including activating transcription factor 3 (Atf3) and CAAT/enhancer-binding protein homologous protein-10 (Chop). In this study, we investigated whether treatment of beta cells with the MS-275, a HDAC1 and HDAC3 activity inhibitor which prevents beta cell death elicited by cytokines, is beneficial for combating beta cell dysfunction caused by palmitate. We show that culture of isolated human islets and MIN6 cells with MS-275 reduced apoptosis evoked by palmitate. The protective effect of MS-275 was associated with the attenuation of the expression of Atf3 and Chop. Silencing of HDAC3, but not of HDAC1, mimicked the effects of MS-275 on the expression of the two ER stress markers and apoptosis. These data point to HDAC3 as a potential drug target for preserving beta cells against lipotoxicity in diabetes.

scholarly journals A Model for Human Islet Transplantation to Immunodeficient Streptozotocin-Induced Diabetic Mice

2018 ◽  
Vol 27 (11) ◽  
pp. 1684-1691 ◽  
Author(s):  
Elisabet Estil·les ◽  
Noèlia Téllez ◽  
Montserrat Nacher ◽  
Eduard Montanya
Keyword(s):  
Cell Death ◽  
Beta Cell ◽  
Beta Cells ◽  
Islet Transplantation ◽  
Cell Mass ◽  
Human Islet ◽  
Diabetic Mice ◽  
Beta Cell Death ◽  
Human Beta Cells ◽  
Human Islet Transplantation

Streptozotocin (STZ) is a cytotoxic glucose analogue that causes beta cell death and is widely used to induce experimental diabetes in rodents. The sensitivity of beta cells to STZ is species-specific and human beta cells are resistant to STZ. In experimental islet transplantation to rodents, STZ-diabetes must be induced before transplantation to avoid destruction of grafted islets by STZ. In human islet transplantation, injection of STZ before transplantation is inconvenient and costly, since human islet availability depends on organ donation and frail STZ-diabetic mice must be kept for unpredictable lapses of time until a human islet preparation is available. Based on the high resistance of human beta cells to STZ, we have tested a new model for STZ-diabetes induction in which STZ is injected after human islet transplantation. Human and mouse islets were transplanted under the kidney capsule of athymic nude mice, and 10–14 days after transplantation mice were intraperitoneally injected with five consecutive daily doses of STZ or vehicle. Beta-cell death increased and beta-cell mass was reduced in mouse islet grafts after STZ injection. In contrast, in human islet grafts beta cell death and mass did not change after STZ injection. Mice transplanted with rodent islets developed hyperglycemia after STZ-injection. Mice transplanted with human islets remained normoglycemic and developed hyperglycemia when the graft was harvested. STZ had no detectable toxic effects on beta cell death, mass and function of human transplanted islets. We provide a new, more convenient and cost-saving model for human islet transplantation to STZ-diabetic recipients in which STZ is injected after islet transplantation.

scholarly journals The adaptor protein NumbL is involved in the control of glucolipotoxicity-induced pancreatic beta cell apoptosis

2020 ◽  
Author(s):  
Halesha D. Basavarajappa ◽  
Jose M. Irimia ◽  
Patrick T. Fueger
Keyword(s):  
Cell Death ◽  
Beta Cell ◽  
Beta Cells ◽  
Cell Apoptosis ◽  
Molecular Mechanisms ◽  
Pancreatic Beta Cell ◽  
Adaptor Protein ◽  
Beta Cell Apoptosis ◽  
Beta Cell Death ◽  
Egf Signaling

AbstractAvoiding loss of functional beta cell mass is critical for preventing or treating diabetes. Currently, the molecular mechanisms underlying beta cell death are partially understood, and there is a need to identify new targets for developing novel therapeutics to treat diabetes. Previously, our group established that Mig6, an inhibitor of EGF signaling, mediates beta cell death under diabetogenic conditions. The objective of this study was to clarify the mechanisms linking diabetogenic stimuli to beta cell death by investigating Mig6-interacting proteins. Using co-immunoprecipitation and mass spectrometry, we evaluated the binding partners of Mig6 under both normal glucose (NG) and glucolipotoxic (GLT) conditions in beta cells. We identified that Mig6 interacts dynamically with NumbL; whereas Mig6 associates with NumbL under NG, this interaction is disrupted under GLT conditions. Further, we demonstrate that siRNA-mediated suppression of NumbL expression in beta cells prevented apoptosis under GLT conditions by blocking activation of NF-κB signaling. Using co-immunoprecipitation experiments we observed that NumbL’s interactions with TRAF6, a key component of NFκB signaling, are increased under GLT conditions. The interactions among Mig6, NumbL, and TRAF6 are dynamic and context-dependent. We propose a model wherein these interactions activate pro-apoptotic NF-κB signaling while blocking pro-survival EGF signaling under diabetogenic conditions, leading to beta cell apoptosis. These findings indicate that NumbL should be further investigated as a candidate anti-diabetic therapeutic target.

scholarly journals The microRNA Landscape of Acute Beta Cell Destruction in Type 1 Diabetic Recipients of Intraportal Islet Grafts

2021 ◽  
Author(s):  
Geert Antoine Martens ◽  
Geert Stange ◽  
Lorenzo Piemonti ◽  
Jasper Anckaert ◽  
Zhidong Ling ◽  
...  
Keyword(s):  
Cell Death ◽  
Beta Cell ◽  
Beta Cells ◽  
Islet Transplantation ◽  
Beta Cell Death ◽  
Beta Cell Destruction ◽  
Cell Destruction ◽  
Graft Outcome ◽  
Plasma Microrna

Ongoing beta cell death in type 1 diabetes (T1D) can be detected using biomarkers selectively discharged by dying beta cells into plasma. MicroRNA-375 (miR-375) ranks among top biomarkers based on studies in animal models and human islet transplantation. Our objective was to identify additional microRNAs that are co-released with miR-375 proportionate to the amount of beta cell destruction. RT-PCR profiling of 733 microRNAs in a discovery cohort of T1D patients 1 hour before/after islet transplantation indicated increased plasma levels of 22 microRNAs. Sub-selection for beta cell selectivity resulted in 15 microRNAs that were subjected to double-blinded multicenter analysis. This led to identification of 8 microRNAs that were consistently increased during early graft destruction: besides miR-375, these included miR-132/204/410/200a/429/125b, microRNAs with known function and enrichment in beta cells. Their potential clinical translation was investigated in a third independent cohort of 46 transplant patients, by correlating post-transplant microRNA levels to C-peptide levels 2 months later. Only miR-375 and miR-132 had prognostic potential for graft outcome and none of the newly identified microRNAs outperformed miR-375 in multiple regression. In conclusion, this study reveals multiple beta cell-enriched microRNAs that are co-released with miR-375 and can be used as complementary biomarkers of beta cell death.

In vitro profiling of endocrine cell death using UCHL1 and GAD65 as soluble biomarkers

2016 ◽  
Author(s):  
Benedicte Brackeva ◽  
Sarah Roels ◽  
Geert Stangé ◽  
Gamze Ates ◽  
Olivier R. Costa ◽  
...  
Keyword(s):  
Cell Death ◽  
Beta Cell ◽  
Beta Cells ◽  
Islet Transplantation ◽  
High Sensitivity ◽  
Low Grade ◽  
Variable Degree ◽  
Beta Cell Death

AbstractBACKGROUNDPancreatic islet grafts are cultured in vitro prior to transplantation and this is associated to a variable degree of beta cell loss. Optimization of culture conditions is currently hampered by the lack of a specific and sensitive in vitro indicator of beta cell death.METHODSWe developed a high-sensitivity duplex bead-based immunoassay for two protein-type biomarkers of beta cell destruction, GAD65 and UCHL1, and investigated its proficiency for in vitro toxicity profiling on rodent and human beta cells, as compared to a semi-automatic and manual image-based assessment of beta cell death, and in vivo after intraportal islet transplantation.RESULTSBoth GAD65 and UCHL1 were discharged by necrotic and apoptotic beta cells proportionate to the number of dead beta cells as counted by microscopic methods. In vitro, UCHL1 was superior to GAD65, in terms of biomarker stability providing more sensitive detection of low grade beta cell death. In vivo, however, GAD65 was consistently detected after islet transplantation while UCHL1 remained undetectable.CONCLUSIONThe use of soluble biomarkers represents a fast, selective and sensitive method for beta cell toxicity profiling in vitro. UCHL1 is superior to GAD65 in vitro but not in vivo.

scholarly journals Prolactin protects against cytokine-induced beta-cell death by NFκB and JNK inhibition

2018 ◽  
Vol 61 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Tarlliza R Nardelli ◽  
Emerielle C Vanzela ◽  
Keli C Benedicto ◽  
Flora Brozzi ◽  
André Fujita ◽  
...  
Keyword(s):  
Cell Death ◽  
Beta Cell ◽  
Beta Cells ◽  
Target Genes ◽  
Interleukin 1 ◽  
Beta Cell Proliferation ◽  
No Production ◽  
Protective Effects ◽  
Beta Cell Death ◽  
Autoimmune Attack

Type 1 diabetes is caused by an autoimmune assault that induces progressive beta-cell dysfunction and dead. Pro-inflammatory cytokines, such as interleukin 1 beta (IL1B), tumor necrosis factor (TNF) and interferon gamma (IFNG) contribute for beta-cell death, which involves the activation of the nuclear factor kappa B (NFκB) and c- Jun N-terminal kinase (JNK). Prolactin (PRL), a physiological mediator for beta-cell proliferation, was shown to protect beta cells against cytokines pro-apoptotic effects. We presently investigated the mechanisms involved in the protective effects of prolactin against cytokine-induced beta-cell death. The findings obtained indicate that STAT3 activation is involved in the anti-apoptotic role of PRL in rat beta cells. PRL prevents the activation of JNK via AKT and promotes a shift from expression of pro- to anti-apoptotic proteins downstream of the JNK cascade. Furthermore, PRL partially prevents the activation of NFκB and the transcription of its target genes IkBa, Fas, Mcp1, A20 and Cxcl10 and also decreases NO production. On the other hand, the pro-survival effects of PRL do not involve modulation of cytokine-induced endoplasmic reticulum stress. These results suggest that the beneficial effects of PRL in beta cells involve augmentation of anti-apoptotic mechanisms and, at the same time, reduction of pro-apoptotic effectors, rendering beta cells better prepared to deal with inflammatory insults. The better understanding of the pro-survival mechanisms modulated by PRL in beta cells can provide tools to prevent cell demise during an autoimmune attack or following islet transplantation.

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