scholarly journals GLP-1 signaling suppresses menin’s transcriptional block by phosphorylation in β cells

2019 ◽  
Vol 218 (3) ◽  
pp. 855-870 ◽  
Author(s):  
Bowen Xing ◽  
Jian Ma ◽  
Zongzhe Jiang ◽  
Zijie Feng ◽  
Sunbin Ling ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Gene Transcription ◽  
Histone Deacetylases ◽  
Cell Function ◽  
Β Cells ◽  
Β Cell ◽  
Histone Modifiers ◽  
Β Cell Function ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

Both menin and glucagon-like peptide 1 (GLP-1) pathways play central yet opposing role in regulating β cell function, with menin suppressing, and GLP-1 promoting, β cell function. However, little is known as to whether or how GLP-1 pathway represses menin function. Here, we show that GLP-1 signaling–activated protein kinase A (PKA) directly phosphorylates menin at the serine 487 residue, relieving menin-mediated suppression of insulin expression and cell proliferation. Mechanistically, Ser487-phosphorylated menin gains increased binding affinity to nuclear actin/myosin IIa proteins and gets sequestrated from the Ins1 promoter. This event leads to reduced binding of repressive epigenetic histone modifiers suppressor variegation 3–9 homologue protein 1 (SUV39H1) and histone deacetylases 1 (HDAC1) at the locus and subsequently increased Ins1 gene transcription. Ser487 phosphorylation of menin also increases expression of proproliferative cyclin D2 and β cell proliferation. Our results have uncovered a previously unappreciated physiological link in which GLP-1 signaling suppresses menin function through phosphorylation-triggered and actin/myosin cytoskeletal protein–mediated derepression of gene transcription.

scholarly journals GPR142 prompts glucagon-like Peptide-1 release from islets to improve β cell function

2018 ◽  
Vol 11 ◽  
pp. 205-211 ◽  
Author(s):  
Hua V. Lin ◽  
Jingru Wang ◽  
Jie Wang ◽  
Weiji Li ◽  
Xuesong Wang ◽  
...  
Keyword(s):  
Cell Function ◽  
Β Cell ◽  
Β Cell Function ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

scholarly journals Basal Receptor Activation by Locally Produced Glucagon-Like Peptide-1 Contributes to Maintaining β-Cell Function

2005 ◽  
Vol 19 (5) ◽  
pp. 1373-1382 ◽  
Author(s):  
Kai Masur ◽  
Elmi C. Tibaduiza ◽  
Ci Chen ◽  
Brooke Ligon ◽  
Martin Beinborn
Keyword(s):  
Cell Function ◽  
Receptor Activation ◽  
Β Cell ◽  
Β Cell Function ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

scholarly journals Emerging role of testosterone in pancreatic β cell function and insulin secretion

2019 ◽  
Vol 240 (3) ◽  
pp. R97-R105 ◽  
Author(s):  
Weiwei Xu ◽  
Jamie Morford ◽  
Franck Mauvais-Jarvis
Keyword(s):  
Insulin Secretion ◽  
Metabolic Regulation ◽  
Cell Function ◽  
Visceral Obesity ◽  
Β Cells ◽  
Β Cell ◽  
Β Cell Function ◽  
Glucagon Like Peptide 1 ◽  
Glucose Stimulated Insulin Secretion

One of the most sexually dimorphic aspects of metabolic regulation is the bidirectional modulation of glucose homeostasis by testosterone in male and females. Severe testosterone deficiency predisposes men to type 2 diabetes (T2D), while in contrast, androgen excess predisposes women to hyperglycemia. The role of androgen deficiency and excess in promoting visceral obesity and insulin resistance in men and women respectively is well established. However, although it is established that hyperglycemia requires β cell dysfunction to develop, the role of testosterone in β cell function is less understood. This review discusses recent evidence that the androgen receptor (AR) is present in male and female β cells. In males, testosterone action on AR in β cells enhances glucose-stimulated insulin secretion by potentiating the insulinotropic action of glucagon-like peptide-1. In females, excess testosterone action via AR in β cells promotes insulin hypersecretion leading to oxidative injury, which in turn predisposes to T2D.

scholarly journals miR-7 Regulates GLP-1-Mediated Insulin Release by Targeting β-Arrestin 1

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1621 ◽  
Author(s):  
Alessandro Matarese ◽  
Jessica Gambardella ◽  
Angela Lombardi ◽  
Xujun Wang ◽  
Gaetano Santulli
Keyword(s):  
Insulin Release ◽  
Cell Function ◽  
Specific Interaction ◽  
Β Cells ◽  
Β Cell Function ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Glucose Stimulated Insulin Secretion ◽  
First Time

Glucagon-like peptide-1 (GLP-1) has been shown to potentiate glucose-stimulated insulin secretion binding GLP-1 receptor on pancreatic β cells. β-arrestin 1 (βARR1) is known to regulate the desensitization of GLP-1 receptor. Mounting evidence indicates that microRNAs (miRNAs, miRs) are fundamental in the regulation of β cell function and insulin release. However, the regulation of GLP-1/βARR1 pathways by miRs has never been explored. Our hypothesis is that specific miRs can modulate the GLP-1/βARR1 axis in β cells. To test this hypothesis, we applied a bioinformatic approach to detect miRs that could target βARR1; we identified hsa-miR-7-5p (miR-7) and we validated the specific interaction of this miR with βARR1. Then, we verified that GLP-1 was indeed able to regulate the transcription of miR-7 and βARR1, and that miR-7 significantly regulated GLP-1-induced insulin release and cyclic AMP (cAMP) production in β cells. Taken together, our findings indicate, for the first time, that miR-7 plays a functional role in the regulation of GLP-1-mediated insulin release by targeting βARR1. These results have a decisive clinical impact given the importance of drugs modulating GLP-1 signaling in the treatment of patients with type 2 diabetes mellitus.

scholarly journals SMAD7 enhances adult β-cell proliferation without significantly affecting β-cell function in mice

2020 ◽  
Vol 295 (15) ◽  
pp. 4858-4869 ◽  
Author(s):  
Anuradha Sehrawat ◽  
Chiyo Shiota ◽  
Nada Mohamed ◽  
Julia DiNicola ◽  
Mohamed Saleh ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Transforming Growth Factor ◽  
Cell Function ◽  
Therapeutic Option ◽  
Transforming Growth Factor Β ◽  
Vital Role ◽  
Negative Effects ◽  
Β Cells ◽  
Β Cell ◽  
Β Cell Function

The interplay between the transforming growth factor β (TGF-β) signaling proteins, SMAD family member 2 (SMAD2) and 3 (SMAD3), and the TGF-β–inhibiting SMAD, SMAD7, seems to play a vital role in proper pancreatic endocrine development and also in normal β-cell function in adult pancreatic islets. Here, we generated conditional SMAD7 knockout mice by crossing insulin1Cre mice with SMAD7fx/fx mice. We also created a β cell–specific SMAD7-overexpressing mouse line by crossing insulin1Dre mice with HPRT-SMAD7/RosaGFP mice. We analyzed β-cell function in adult islets when SMAD7 was either absent or overexpressed in β cells. Loss of SMAD7 in β cells inhibited proliferation, and SMAD7 overexpression enhanced cell proliferation. However, alterations in basic glucose homeostasis were not detectable following either SMAD7 deletion or overexpression in β cells. Our results show that both the absence and overexpression of SMAD7 affect TGF-β signaling and modulates β-cell proliferation but does not appear to alter β-cell function. Reversible SMAD7 overexpression may represent an attractive therapeutic option to enhance β-cell proliferation without negative effects on β-cell function.

scholarly journals Exploiting the antidiabetic properties of incretins to treat type 2 diabetes mellitus: glucagon-like peptide 1 receptor agonists or insulin for patients with inadequate glycemic control?

2008 ◽  
Vol 158 (6) ◽  
pp. 773-784 ◽  
Author(s):  
Luc F Van Gaal ◽  
Stephen W Gutkin ◽  
Michael A Nauck
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
Body Weight ◽  
Cell Function ◽  
Β Cell ◽  
Β Cell Function ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

Type 2 diabetes mellitus is associated with progressive decreases in pancreatic β-cell function. Most patients thus require increasingly intensive treatment, including oral combination therapies followed by insulin. Fear of hypoglycemia is a potential barrier to treatment adherence and glycemic control, while weight gain can exacerbate hyperglycemia or insulin resistance. Administration of insulin can roughly mimic physiologic insulin secretion but does not address underlying pathophysiology. Glucagon-like peptide 1 (GLP-1) is an incretin hormone released by the gut in response to meal intake that helps to maintain glucose homeostasis through coordinated effects on islet α- and β-cells, inhibiting glucagon output, and stimulating insulin secretion in a glucose-dependent manner. Biological effects of GLP-1 include slowing gastric emptying and decreasing appetite. Incretin mimetics (GLP-1 receptor agonists with more suitable pharmacokinetic properties versus GLP-1) significantly lower hemoglobin A1c, body weight, and postprandial glucose excursions in humans and significantly improve β-cell function in vivo (animal data). These novel incretin-based therapies offer the potential to reduce body weight or prevent weight gain, although the durability of these effects and their potential long-term benefits need to be studied further. This article reviews recent clinical trials comparing therapy with the incretin mimetic exenatide to insulin in patients with oral treatment failure, identifies factors consistent with the use of each treatment, and delineates areas for future research.

scholarly journals Exaggerated Glucagon-Like Peptide 1 Response Is Important for Improved β-Cell Function and Glucose Tolerance After Roux-en-Y Gastric Bypass in Patients With Type 2 Diabetes

Diabetes ◽  
2013 ◽  
Vol 62 (9) ◽  
pp. 3044-3052 ◽  
Author(s):  
Nils B. Jørgensen ◽  
Carsten Dirksen ◽  
Kirstine N. Bojsen-Møller ◽  
Siv H. Jacobsen ◽  
Dorte Worm ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Gastric Bypass ◽  
Glucose Tolerance ◽  
Cell Function ◽  
Β Cell ◽  
Β Cell Function ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

Determinants of glucose metabolism and the role of NPY in the progression of insulin resistance in chronic migraine

Cephalalgia ◽  
2017 ◽  
Vol 38 (11) ◽  
pp. 1773-1781 ◽  
Author(s):  
Zeynep Oşar Siva ◽  
Derya Uluduz ◽  
Fatma Ela Keskin ◽  
Feyza Erenler ◽  
Huriye Balcı ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Neuropeptide Y ◽  
Chronic Migraine ◽  
Cell Function ◽  
Episodic Migraine ◽  
Oral Glucose ◽  
Β Cell ◽  
Β Cell Function ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

Background Chronic migraine has a well-documented association with increased insulin resistance and metabolic syndrome. The hypothalamus may play a role in the progression of insulin resistance in chronic migraine through the regulation of orexigenic peptides such as neuropeptide Y. Insulin resistance may lead to increased risk of future type 2 diabetes mellitus in patients with chronic migraine, which is more likely to occur if other pathogenetic defects of type 2 diabetes mellitus, such as impaired pancreatic β-cell functions and defects in intestinal glucagon-like peptide-1 secretion after meals. We studied the relationship of fasting neuropeptide Y with insulin resistance, β-cell function, and glucagon-like peptide-1 secretion in non-obese female chronic migraine patients. We also aimed to investigate glucose-stimulated insulin and glucagon-like peptide-1 secretions as early pathogenetic mechanisms responsible for the development of carbohydrate intolerance. Methods In this cross-sectional controlled study, 83 non-obese female migraine patients of reproductive age categorized as having episodic migraine or chronic migraine were included. The control group consisted of 36 healthy females. We studied glucose-stimulated insulin and glucagon-like peptide-1 secretion during a 75 g oral glucose tolerance test. We investigated the relationship of neuropeptide Y levels with insulin resistance and β-cell insulin secretion functions. Results Fasting glucose levels were significantly higher in migraine patients. Plasma glucose and insulin levels during the oral glucose tolerance test were otherwise similar in chronic migraine, episodic migraine and controls. Patients with chronic migraine were more insulin resistant than episodic migraine or controls ( p = 0.048). Glucagon-like peptide-1 levels both at fasting and two hours after glucose intake were similar in chronic migraine, episodic migraine, and controls. Neuropeptide Y levels were higher in migraineurs. In chronic migraine, neuropeptide Y was positively correlated with fasting glucagon-like peptide-1 levels (r = 0.57, p = 0.04), but there was no correlation with insulin resistance (r = 0.49, p = 0.09) or β-cell function (r = 0.50, p = 0.07). Discussion Non-obese premenopausal female patients with chronic migraine have higher insulin resistance, but normal β-cell function is to compensate for the increased insulin demand during fasting and after glucose intake. Increased fasting neuropeptide Y levels in migraine may be a factor leading to increased insulin resistance by specific alterations in energy intake and activation of the sympathoadrenal system.

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