scholarly journals The role of long non-coding RNAs in the regulation of pancreatic beta cell identity

Author(s):  
Maya E. Wilson ◽  
Timothy J. Pullen

Type 2 diabetes (T2D) is a widespread disease affecting millions in every continental population. Pancreatic β-cells are central to the regulation of circulating glucose, but failure in the maintenance of their mass and/or functional identity leads to T2D. Long non-coding RNAs (lncRNAs) represent a relatively understudied class of transcripts which growing evidence implicates in diabetes pathogenesis. T2D-associated single nucleotide polymorphisms (SNPs) have been identified in lncRNA loci, although these appear to function primarily through regulating β-cell proliferation. In the last decade, over 1100 lncRNAs have been catalogued in islets and the roles of a few have been further investigated, definitively linking them to β-cell function. These studies show that lncRNAs can be developmentally regulated and show highly tissue-specific expression. lncRNAs regulate neighbouring β-cell-specific transcription factor expression, with knockdown or overexpression of lncRNAs impacting a network of other key genes and pathways. Finally, gene expression analysis in studies of diabetic models have uncovered a number of lncRNAs with roles in β-cell function. A deeper understanding of these lncRNA roles in maintaining β-cell identity, and its deterioration, is required to fully appreciate the β-cell molecular network and to advance novel diabetes treatments.

2012 ◽  
Vol 14 ◽  
pp. 12-21 ◽  
Author(s):  
C. Guay ◽  
C. Jacovetti ◽  
V. Nesca ◽  
A. Motterle ◽  
K. Tugay ◽  
...  

2021 ◽  
Author(s):  
Chien-Wen Chen ◽  
Bo-Jhih Guan ◽  
Mohammed R Alzahrani ◽  
Zhaofeng Gao ◽  
Long Gao ◽  
...  

Pancreatic β-cells undergo high levels of endoplasmic reticulum (ER) stress due to their role in insulin secretion. Hence, they require sustainable and efficient adaptive stress responses to cope with the stress. Whether duration and episodes of chronic ER stress directly compromises β-cell identity is largely unknown. We show that under reversible, chronic ER stress, β-cells undergo a distinct transcriptional and translational reprogramming. During reprogramming, expression of master regulators of β-cell function and identity and proinsulin processing is impaired. Upon recovery from stress, β-cells regain their identity, highlighting a high-degree of adaptive β-cell plasticity. Remarkably, when stress episodes exceed a certain threshold, β-cell identity is gradually lost. Single cell RNA-seq analysis of islets from type 1 diabetes (T1D) patients, identifies the severe deregulation of the chronic stress-adaptation program, and reveals novel biomarkers for progression of T1D. Our results suggest β-cell adaptive exhaustion (βEAR) is a significant component of the pathogenesis of T1D.


Author(s):  
Xiaoyang Lai ◽  
Xuyang Liu ◽  
Xia Cai ◽  
Fang Zou

Type 1 diabetes (T1D) is a chronic autoimmune disease accompanied by the immune-mediated destruction of pancreatic β-cells. In this study, we aimed to explore the regulatory effects of Vitamin D (VD) supplementation on pancreatic β-cell function by altering the expression of bioinformatically identified cathepsin G (CatG) in T1D model mice. A T1D mouse model was established in non-obese diabetic (NOD) mice, and their islets were isolated and purified. Pancreatic mononuclear cells (MNCs) were collected, from which CD4+ T cells were isolated. The levels of interleukin (IL)-2, IL-10, tumor necrosis factor-α (TNF-α) and interferon-gamma (IFN-γ) in the supernatant of mouse pancreatic tissue homogenate were assessed using ELISA. Immunohistochemistry and TUNEL staining were conducted to evaluate the effects of VD supplementation on pancreatic tissues of T1D mice. The pancreatic beta-cell line MIN6 was used for in vitro substantiation of findings in vivo. VD supplementation reduced glucose levels and improved glucose tolerance in T1D mice. Further, VD supplementation improved pancreatic β-cell function and suppressed immunological and inflammatory reactions in the T1D mice. We documented overexpression of CatG in diabetes tissue samples, and then showed that VD supplementation normalized the islet immune microenvironment through down-regulating CatG expression in T1D mice. Experiments in vitro subsequently demonstrated that VD supplementation impeded CD4+ T activation by down-regulating CatG expression, and thereby enhanced pancreatic β-cell function. Results of the present study elucidated that VD supplementation can down-regulate the expression of CatG and inhibit CD4+ T cell activation, thereby improving β-cell function in T1D.


2017 ◽  
Vol 11 (1) ◽  
Author(s):  
Aashiq H. Mirza ◽  
Simranjeet Kaur ◽  
Flemming Pociot

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mildred Fátima de la Luz Alvarez-Canales ◽  
Sara Stephania Salazar-López ◽  
Diana Farfán-Vázquez ◽  
Yosceline Estrella Martínez-López ◽  
Jessica Noemí González-Mena ◽  
...  

AbstractThe goal of the study was to evaluate the effect of adding linagliptin to metformin and lifestyle on glucose levels and pancreatic β-cell function in patients with persistent impaired glucose tolerance (IGT) after 12 months of metformin and lifestyle. A single center parallel double-blind randomized clinical trial with 6 months of follow-up was performed in patients with persistent IGT after 12 months of treatment with metformin and lifestyle; patients were randomized to continue with metformin 850 mg twice daily (M group, n = 12) or linagliptin/metformin 2.5/850 mg twice daily (LM group, n = 19). Anthropometric measurements were obtained by standard methods and by bioelectrical impedance; glucose was measured by dry chemistry, insulin by chemiluminescence, and pancreatic β-cell function was calculated with the disposition index using glucose and insulin values during oral glucose tolerance test (OGTT) and adjusting by insulin sensitivity. The main outcomes were glucose levels during OGTT and pancreatic β-cell function. Patients in the LM group had a reduction in weight (−1.7 ± 0.6, p < 0.05) and body mass index (BMI, −0.67 ± 0.2, p < 0.05). Glucose levels significantly improved in LM group with a greater reduction in the area under the glucose curve during OGTT (AUCGluc0_120min) as compared to the M group (−4425 ± 871 vs −1116 ± 1104 mg/dl/120 min, p < 0.001). Pancreatic β-cell function measured with the disposition index, improved only in LM group (2.3 ± 0.23 vs 1.7 ± 0.27, p 0.001); these improvements persisted after controlling for OGTT glucose levels. The differences in pancreatic β-cell function persisted also after pairing groups for basal AUCGluc0_120min. The addition of linagliptin to patients with persistent IGT after 12 months of treatment with metformin and lifestyle, improved glucose levels during OGTT and pancreatic β-cell function after 6 months of treatment.Trial registration: Clinicaltrials.gov with the ID number NCT04088461


2015 ◽  
Vol 60 (8) ◽  
pp. 2529-2537 ◽  
Author(s):  
Mohammad S. Siddiqui ◽  
Kai L. Cheang ◽  
Velimir A. Luketic ◽  
Sherry Boyett ◽  
Michael O. Idowu ◽  
...  

2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Linlin Zhang ◽  
Chunxiang Sheng ◽  
Feiye Zhou ◽  
Kecheng Zhu ◽  
Shushu Wang ◽  
...  

AbstractLoss of β cell identity and functional immaturity are thought to be involved in β cell failure in type 2 diabetes. CREB-binding protein (CBP) and its paralogue p300 act as multifunctional transcriptional co-activators and histone acetyltransferases (HAT) with extensive biological functions. However, whether the regulatory role of CBP/p300 in islet β cell function depends on the HAT activity remains uncertain. In this current study, A-485, a selective inhibitor of CBP/p300 HAT activity, greatly impaired glucose-stimulated insulin secretion from rat islets in vitro and in vivo. RNA-sequencing analysis showed a comprehensive downregulation of β cell and α cell identity genes in A-485-treated islets, without upregulation of dedifferentiation markers and derepression of disallowed genes. A-485 treatment decreased the expressions of genes involved in glucose sensing, not in glycolysis, tricarboxylic acid cycle, and oxidative phosphorylation. In the islets of prediabetic db/db mice, CBP/p300 displayed a significant decrease with key genes for β cell function. The deacetylation of histone H3K27 as well as the transcription factors Hnf1α and Foxo1 was involved in CBP/p300 HAT inactivation-repressed expressions of β cell identity and functional genes. These findings highlight the dominant role of CBP/p300 HAT in the maintenance of β cell identity by governing transcription network.


2017 ◽  
Vol 6 (8) ◽  
pp. 811-816 ◽  
Author(s):  
Thozhukat Sathyapalan ◽  
Anne-Marie Coady ◽  
Eric S Kilpatrick ◽  
Stephen L Atkin

Background There is an increased risk of developing T2DM in women with polycystic ovary syndrome (PCOS), and there is evidence that statins improve metabolic parameters in these patients. However, there are some data to show that statins increase the risk of incipient diabetes. Materials and methods We have previously shown that 12 weeks of atorvastatin improves insulin resistance when measured using HOMA-IR. This post hoc analysis was designed to look at the effect of atorvastatin on pancreatic β cell function using HOMA-β in the same study. In this randomised, double-blind placebo controlled study, 40 medication-naïve patients with PCOS were randomised to either atorvastatin 20 mg daily or placebo for 3 months. A 3-month extension study for both groups of patients was undertaken with metformin 1500 mg daily after completing initial 3 months of atorvastatin or placebo. Results There was a significant reduction in HOMA-β (240 ± 3.2 vs 177 ± 2.3; P value <0.01) after 12 weeks of atorvastatin treatment, which was maintained by metformin in the subsequent 12 weeks. There were no changes in HOMA-β after the placebo or after subsequent metformin treatment. There was no linear correlation between reduction in HOMA-β with improvement of free androgen index (FAI) (r2 = 0.02; P = 0.72), testosterone (r2 = 0.13; P = 0.49), SHBG (r2 = 0.22; P = 0.48), hsCRP (r2 = 0.19; P = 0.64), triglycerides (r2 = 0.09; P = 0.12), total cholesterol (r2 = 0.11; P = 0.32) or LDL-C (r2 = 0.19; P = 0.38). Conclusion Treatment with atorvastatin for 12 weeks in women with PCOS significantly reduced HOMA-β. This could be potentially due to fall in β-cell requirement with improvement of insulin resistance rather than a reduction of β-cell function.


2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Dina Mostafa ◽  
Akiko Yanagiya ◽  
Eleni Georgiadou ◽  
Yibo Wu ◽  
Theodoros Stylianides ◽  
...  

AbstractPancreatic β-cells are responsible for production and secretion of insulin in response to increasing blood glucose levels. Defects in β-cell function lead to hyperglycemia and diabetes mellitus. Here, we show that CNOT3, a CCR4–NOT deadenylase complex subunit, is dysregulated in islets in diabetic db/db mice, and that it is essential for murine β cell maturation and identity. Mice with β cell-specific Cnot3 deletion (Cnot3βKO) exhibit impaired glucose tolerance, decreased β cell mass, and they gradually develop diabetes. Cnot3βKO islets display decreased expression of key regulators of β cell maturation and function. Moreover, they show an increase of progenitor cell markers, β cell-disallowed genes, and genes relevant to altered β cell function. Cnot3βKO islets exhibit altered deadenylation and increased mRNA stability, partly accounting for the increased expression of those genes. Together, these data reveal that CNOT3-mediated mRNA deadenylation and decay constitute previously unsuspected post-transcriptional mechanisms essential for β cell identity.


2019 ◽  
Vol 133 (22) ◽  
pp. 2317-2327 ◽  
Author(s):  
Nicolás Gómez-Banoy ◽  
James C. Lo

Abstract The growing prevalence of obesity and its related metabolic diseases, mainly Type 2 diabetes (T2D), has increased the interest in adipose tissue (AT) and its role as a principal metabolic orchestrator. Two decades of research have now shown that ATs act as an endocrine organ, secreting soluble factors termed adipocytokines or adipokines. These adipokines play crucial roles in whole-body metabolism with different mechanisms of action largely dependent on the tissue or cell type they are acting on. The pancreatic β cell, a key regulator of glucose metabolism due to its ability to produce and secrete insulin, has been identified as a target for several adipokines. This review will focus on how adipokines affect pancreatic β cell function and their impact on pancreatic β cell survival in disease contexts such as diabetes. Initially, the “classic” adipokines will be discussed, followed by novel secreted adipocyte-specific factors that show therapeutic promise in regulating the adipose–pancreatic β cell axis.


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