scholarly journals Large-Scale Functional Genomics Screen to Identify Modulators of Human β-Cell Insulin Secretion

Biomedicines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 103
Author(s):  
Iwona Szczerbinska ◽  
Annamaria Tessitore ◽  
Lena Kristina Hansson ◽  
Asmita Agrawal ◽  
Alejandro Ragel Lopez ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Candidate Genes ◽  
Drug Targets ◽  
Large Scale ◽  
Cell Mass ◽  
Β Cell ◽  
Cellular Mechanisms ◽  
Ghrelin Receptor ◽  
Novel Drug

Type 2 diabetes (T2D) is a chronic metabolic disorder affecting almost half a billion people worldwide. Impaired function of pancreatic β-cells is both a hallmark of T2D and an underlying factor in the pathophysiology of the disease. Understanding the cellular mechanisms regulating appropriate insulin secretion has been of long-standing interest in the scientific and clinical communities. To identify novel genes regulating insulin secretion we developed a robust arrayed siRNA screen measuring basal, glucose-stimulated, and augmented insulin secretion by EndoC-βH1 cells, a human β-cell line, in a 384-well plate format. We screened 521 candidate genes selected by text mining for relevance to T2D biology and identified 23 positive and 68 negative regulators of insulin secretion. Among these, we validated ghrelin receptor (GHSR), and two genes implicated in endoplasmic reticulum stress, ATF4 and HSPA5. Thus, we have demonstrated the feasibility of using EndoC-βH1 cells for large-scale siRNA screening to identify candidate genes regulating β-cell insulin secretion as potential novel drug targets. Furthermore, this screening format can be adapted to other disease-relevant functional endpoints to enable large-scale screening for targets regulating cellular mechanisms contributing to the progressive loss of functional β-cell mass occurring in T2D.

Analysis of compensatory β-cell response in mice with combined mutations of Insr and Irs2

2007 ◽  
Vol 292 (6) ◽  
pp. E1694-E1701 ◽  
Author(s):  
Jane J. Kim ◽  
Yoshiaki Kido ◽  
Philipp E. Scherer ◽  
Morris F. White ◽  
Domenico Accili
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Insulin Secretion ◽  
Cell Response ◽  
Cell Mass ◽  
Comprehensive Treatment ◽  
Β Cell ◽  
Cell Dysfunction ◽  
Impaired Insulin

Type 2 diabetes results from impaired insulin action and β-cell dysfunction. There are at least two components to β-cell dysfunction: impaired insulin secretion and decreased β-cell mass. To analyze how these two variables contribute to the progressive deterioration of metabolic control seen in diabetes, we asked whether mice with impaired β-cell growth due to Irs2 ablation would be able to mount a compensatory response in the background of insulin resistance caused by Insr haploinsufficiency. As previously reported, ∼70% of mice with combined Insr and Irs2 mutations developed diabetes as a consequence of markedly decreased β-cell mass. In the initial phases of the disease, we observed a robust increase in circulating insulin levels, even as β-cell mass gradually declined, indicating that replication-defective β-cells compensate for insulin resistance by increasing insulin secretion. These data provide further evidence for a heterogeneous β-cell response to insulin resistance, in which compensation can be temporarily achieved by increasing function when mass is limited. The eventual failure of compensatory insulin secretion suggests that a comprehensive treatment of β-cell dysfunction in type 2 diabetes should positively affect both aspects of β-cell physiology.

scholarly journals A Mathematical Model of the Pathogenesis, Prevention, and Reversal of Type 2 Diabetes

Endocrinology ◽  
2015 ◽  
Vol 157 (2) ◽  
pp. 624-635 ◽  
Author(s):  
Joon Ha ◽  
Leslie S. Satin ◽  
Arthur S. Sherman
Keyword(s):  
Mathematical Model ◽  
Type 2 Diabetes ◽  
Insulin Secretion ◽  
Cell Function ◽  
Cell Mass ◽  
Β Cell ◽  
Metabolic Defects ◽  
Normal Individuals ◽  
Β Cell Function

Abstract Type 2 diabetes (T2D) is generally thought to result from the combination of 2 metabolic defects, insulin resistance, which increases the level of insulin required to maintain glucose within the normal range, and failure of insulin-secreting pancreatic β-cells to compensate for the increased demand. We build on a mathematical model pioneered by Topp and colleagues to elucidate how compensation succeeds or fails. Their model added a layer of slow negative feedback to the classic insulin-glucose loop in the form of a slow, glucose-dependent birth and death law governing β-cell mass. We add to that model regulation of 2 aspects of β-cell function on intermediate time scales. The model quantifies the relative contributions of insulin action and insulin secretion defects to T2D and explains why prevention is easier than cure. The latter is a consequence of a threshold separating the normoglycemic and diabetic states (bistability), which also underlies the success of bariatric surgery and acute caloric restriction in rapidly reversing T2D. The threshold concept gives new insight into “Starling's Law of the Pancreas,” whereby insulin secretion is higher for prediabetics and early diabetics than for normal individuals.

scholarly journals Five stages of progressive β-cell dysfunction in the laboratory Nile rat model of type 2 diabetes

2016 ◽  
Vol 229 (3) ◽  
pp. 343-356 ◽  
Author(s):  
Kaiyuan Yang ◽  
Jonathan Gotzmann ◽  
Sharee Kuny ◽  
Hui Huang ◽  
Yves Sauvé ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Insulin Secretion ◽  
Pancreatic Islet ◽  
Cell Mass ◽  
Β Cell ◽  
High Fiber ◽  
Insulin Resistant ◽  
Cell Dysfunction

We compared the evolution of insulin resistance, hyperglycemia, and pancreatic β-cell dysfunction in the Nile rat (Arvicanthis niloticus), a diurnal rodent model of spontaneous type 2 diabetes (T2D), when maintained on regular laboratory chow versus a high-fiber diet. Chow-fed Nile rats already displayed symptoms characteristic of insulin resistance at 2 months (increased fat/lean mass ratio and hyperinsulinemia). Hyperglycemia was first detected at 6 months, with increased incidence at 12 months. By this age, pancreatic islet structure was disrupted (increased α-cell area), insulin secretion was impaired (reduced insulin secretion and content) in isolated islets, insulin processing was compromised (accumulation of proinsulin and C-peptide inside islets), and endoplasmic reticulum (ER) chaperone protein ERp44 was upregulated in insulin-producing β-cells. By contrast, high-fiber-fed Nile rats had normoglycemia with compensatory increase in β-cell mass resulting in maintained pancreatic function. Fasting glucose levels were predicted by the α/β-cell ratios. Our results show that Nile rats fed chow recapitulate the five stages of progression of T2D as occurs in human disease, including insulin-resistant hyperglycemia and pancreatic islet β-cell dysfunction associated with ER stress. Modification of diet alone permits long-term β-cell compensation and prevents T2D.

scholarly journals Session 7: Early nutrition and later health Early developmental pathways of obesity and diabetes risk

2007 ◽  
Vol 66 (3) ◽  
pp. 451-457 ◽  
Author(s):  
D. B. Dunger ◽  
B. Salgin ◽  
K. K. Ong
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Insulin Secretion ◽  
Weight Gain ◽  
Cell Mass ◽  
Disposition Index ◽  
Β Cell ◽  
Igf I ◽  
The Face

Size at birth and patterns of postnatal weight gain have been associated with adult risk for the development of type 2 diabetes in many populations, but the putative pathophysiological link remains unknown. Studies of contemporary populations indicate that rapid infancy weight gain, which may follow fetal growth restriction, is an important risk factor for the development of childhood obesity and insulin resistance. Data from the Avon Longitudinal Study of Pregnancy and Childhood shows that rapid catch-up weight gain can lead to the development of insulin resistance, as early as 1 year of age, in association with increasing accumulation of central abdominal fat mass. In contrast, the disposition index, which reflects the β-cells ability to maintain insulin secretion in the face of increasing insulin resistance, is much more closely related to ponderal index at birth than postnatal catch-up weight gain. Infants with the lowest ponderal index at birth show a reduced disposition index at aged 8 years associated with increases in fasting NEFA levels. The disposition index is also closely related to childhood height gain and insulin-like growth factor-I (IGF-I) levels; reduced insulin secretory capacity being associated with reduced statural growth, and relatively short stature with reduced IGF-I levels at age 8 years. IGF-I may have an important role in the maintenance of β-cell mass, as demonstrated by recent studies of pancreatic β-cell IGF-I receptor knock-out and adult observational studies indicating that low IGF-I levels are predictive of subsequent risk for the development of type 2 diabetes. However, as insulin secretion is an important determinant of IGF-I levels, cause and effect may be difficult to establish. In conclusion, although rapid infancy weight gain and increasing rates of childhood obesity will increase the risk for the development of insulin resistance, prenatal and postnatal determinants of β-cell mass may ultimately be the most important determinants of an individual's ability to maintain insulin secretion in the face of increasing insulin resistance, and thus risk for the development of type 2 diabetes.

scholarly journals Insulin: The Friend and the Foe in the Development of Type 2 Diabetes Mellitus

2020 ◽  
Vol 21 (5) ◽  
pp. 1770
Author(s):  
Nadia Rachdaoui
Keyword(s):  
Diabetes Mellitus ◽  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
Insulin Secretion ◽  
Cell Mass ◽  
Β Cells ◽  
Β Cell ◽  
Peripheral Insulin Resistance

Insulin, a hormone produced by pancreatic β-cells, has a primary function of maintaining glucose homeostasis. Deficiencies in β-cell insulin secretion result in the development of type 1 and type 2 diabetes, metabolic disorders characterized by high levels of blood glucose. Type 2 diabetes mellitus (T2DM) is characterized by the presence of peripheral insulin resistance in tissues such as skeletal muscle, adipose tissue and liver and develops when β-cells fail to compensate for the peripheral insulin resistance. Insulin resistance triggers a rise in insulin demand and leads to β-cell compensation by increasing both β-cell mass and insulin secretion and leads to the development of hyperinsulinemia. In a vicious cycle, hyperinsulinemia exacerbates the metabolic dysregulations that lead to β-cell failure and the development of T2DM. Insulin and IGF-1 signaling pathways play critical roles in maintaining the differentiated phenotype of β-cells. The autocrine actions of secreted insulin on β-cells is still controversial; work by us and others has shown positive and negative actions by insulin on β-cells. We discuss findings that support the concept of an autocrine action of secreted insulin on β-cells. The hypothesis of whether, during the development of T2DM, secreted insulin initially acts as a friend and contributes to β-cell compensation and then, at a later stage, becomes a foe and contributes to β-cell decompensation will be discussed.

β-Cell compensation concomitant with adaptive endoplasmic reticulum stress and β-cell neogenesis in a diet-induced type 2 diabetes model

2019 ◽  
Vol 44 (12) ◽  
pp. 1355-1366 ◽  
Author(s):  
Hui Huang ◽  
Kaiyuan Yang ◽  
Rennian Wang ◽  
Woo Hyun Han ◽  
Sharee Kuny ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Endoplasmic Reticulum ◽  
Insulin Secretion ◽  
Cell Function ◽  
Cell Mass ◽  
Temporal Association ◽  
Adaptive Responses ◽  
Β Cells ◽  
Β Cell

Insulin-secreting pancreatic β-cells adapt to obesity-related insulin resistance via increases in insulin secretion and β-cell mass. Failed β-cell compensation predicts the onset of type 2 diabetes (T2D). However, the mechanisms of β-cell compensation are not fully understood. Our previous study reported changes in β-cell mass during the progression of T2D in the Nile rat (NR; Arvicanthis niloticus) fed standard chow. In the present study, we measured other β-cell adaptive responses, including glucose metabolism and β-cell insulin secretion in NRs at different ages, thus characterizing NR at 2 months as a model of β-cell compensation followed by decompensation at 6 months. We observed increased proinsulin secretion in the transition from compensation to decompensation, which is indicative of impaired insulin processing. Subsequently, we compared adaptive unfolded protein response in β-cells and demonstrated a positive role of endoplasmic reticulum (ER) chaperones in insulin secretion. In addition, the incidence of insulin-positive neogenic but not proliferative cells increased during the compensation phase, suggesting nonproliferative β-cell growth as a mechanism of β-cell mass adaptation. In contrast, decreased neogenesis and β-cell dedifferentiation were observed in β-cell dysfunction. Furthermore, the progression of T2D and pathophysiological changes of β-cells were prevented by increasing fibre content of the diet. Novelty Our study characterized a novel model for β-cell compensation with adaptive responses in cell function and mass. The temporal association of adaptive ER chaperones with blood insulin and glucose suggests upregulated chaperone capacity as an adaptive mechanism. β-Cell neogenesis but not proliferation contributes to β-cell mass adaptation.

scholarly journals Islet Insulin Secretion, β-Cell Mass, and Energy Balance in a Polygenic Mouse Model of Type 2 Diabetes With Obesity

2014 ◽  
Vol 2 ◽  
pp. 232640981452815 ◽  
Author(s):  
Xia Mao ◽  
Kristy D. Dillon ◽  
Michael F. McEntee ◽  
Arnold M. Saxton ◽  
Jung Han Kim
Keyword(s):  
Type 2 Diabetes ◽  
Insulin Secretion ◽  
Energy Balance ◽  
Mouse Model ◽  
Cell Mass ◽  
Β Cell

Identification of Glucose-Dependent Insulin Secretion Targets in Pancreatic β Cells by Combining Defined-Mechanism Compound Library Screening and siRNA Gene Silencing

2008 ◽  
Vol 13 (2) ◽  
pp. 128-134 ◽  
Author(s):  
Weizhen Wu ◽  
Jin Shang ◽  
Yue Feng ◽  
Chris M. Thompson ◽  
Sarah Horwitz ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Drug Targets ◽  
Target Identification ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Major Bottleneck ◽  
Novel Drug ◽  
Potential Drug Targets ◽  
Novel Drug Targets

Identification and validation of novel drug targets continues to be a major bottleneck in drug development, particularly for polygenic complex diseases such as type 2 diabetes. Here, the authors describe an approach that allows researchers to rapidly identify and validate potential drug targets by combining chemical tools and RNA interference technology. As a proof-of-concept study, the known mechanism Sigma LOPAC library was used to screen for glucose-dependent insulin secretion (GDIS) in INS-1 832/13 cells. In addition to several mechanisms that are known to regulate GDIS (such as cyclic adenosine monophosphate—specific phosphodiesterases, adrenoceptors, and Ca2+ channels), the authors find that several of the dopamine receptor ( DRD) antagonists significantly enhance GDIS, whereas DRD agonists profoundly inhibit GDIS. Subsequent siRNA studies in the same cell line indicate that knockdown of DRD2 enhanced GDIS. Furthermore, selective DRD2 antagonists and agonists also enhance or suppress, respectively, GDIS in isolated rat islets. The data support that the approach described here offers a rapid and effective way for target identification and validation. ( Journal of Biomolecular Screening 2008;128-134)

scholarly journals Assignment of Functional Relevance to Genes at Type 2 Diabetes-Associated Loci Through Investigation of β-Cell Mass Deficits

2016 ◽  
Vol 30 (4) ◽  
pp. 429-445 ◽  
Author(s):  
Elizabeth A. O'Hare ◽  
Laura M. Yerges-Armstrong ◽  
James A. Perry ◽  
Alan R. Shuldiner ◽  
Norann A. Zaghloul
Keyword(s):  
Type 2 Diabetes ◽  
Candidate Genes ◽  
Age Of Onset ◽  
Cell Mass ◽  
Transgenic Zebrafish ◽  
Potential Contribution ◽  
Β Cells ◽  
Β Cell ◽  
Multiple Genes

Type 2 diabetes (T2D) has been associated with a large number of genomic loci, many of which encompass multiple genes without a definitive causal gene. This complexity has hindered efforts to clearly identify functional candidate genes and interpret their role in mediating susceptibility to disease. Here we examined the relevance of individual genes found at T2D-associated loci by assessing their potential contribution to a phenotype relevant to the disease state: production and maintenance of β-cell mass. Using transgenic zebrafish in which β-cell mass could be rapidly visualized in vivo, we systematically suppressed the expression of orthologs of genes found at T2D-associated genomic loci. Overall, we tested 67 orthologs, many of which had no known relevance to β-cell mass, at 62 human T2D-associated loci, including eight loci with multiple candidate genes. In total we identified 25 genes that were necessary for proper β-cell mass, providing functional evidence for their role in a physiological phenotype directly related to T2D. Of these, 16 had not previously been implicated in the regulation of β-cell mass. Strikingly, we identified single functional candidate genes at the majority of the loci for which multiple genes were analyzed. Further investigation into the contribution of the 25 genes to the adaptive capacity of β-cells suggested that the majority of genes were not required for glucose-induced expansion of β-cell mass but were significantly necessary for the regeneration of β-cells. These findings suggest that genetically programmed deficiencies in β-cell mass may be related to impaired maintenance. Finally, we investigated the relevance of our findings to human T2D onset in diabetic individuals from the Old Order Amish and found that risk alleles in β-cell mass genes were associated with significantly younger age of onset and lower body mass index. Taken together, our study offers a functional approach to assign relevance to genes at T2D-associated loci and offers experimental evidence for the defining role of β-cell mass maintenance in genetic susceptibility to T2D onset.

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