| 1. |
- Aljaibeji, Hayat, et al.
(författare)
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Reduced Expression of PLCXD3 Associates With Disruption of Glucose Sensing and Insulin Signaling in Pancreatic β-Cells
- 2019
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Ingår i: Frontiers in Endocrinology. - : Frontiers Media SA. - 1664-2392. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Previous work has shown that reduced expression of PLCXD3, a member of the phosphoinositide-specific phospholipases (PI-PLC) family, impaired insulin secretion with an unclear mechanism. In the current study, we aim to investigate the mechanism underlying this effect using human islets and rat INS-1 (832/13) cells. Microarray and RNA sequencing data showed that PLCXD3 is among the highly expressed PI-PLCs in human islets and INS-1 (832/13) cells. Expression of PLCXD3 was reduced in human diabetic islets, correlated positively with Insulin and GLP1R expression and inversely with the donor's body mass index (BMI) and glycated hemoglobin (HbA1c). Expression silencing of PLCXD3 in INS-1 (832/13) cells was found to reduce glucose-stimulated insulin secretion (GSIS) and insulin content. In addition, the expression of Insulin, NEUROD1, GLUT2, GCK, INSR, IRS2, and AKT was downregulated. Cell viability and apoptosis rate were unaffected. In conclusion, our data suggest that low expression of PLCXD3 in pancreatic β-cells associates with downregulation of the key insulin signaling and insulin biosynthesis genes as well as reduction in glucose sensing.
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| 2. |
- Taneera, Jalal, et al.
(författare)
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GNAS gene is an important regulator of insulin secretory capacity in pancreatic β-cells
- 2019
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Ingår i: Gene. - : Elsevier BV. - 1879-0038 .- 0378-1119. ; 715
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Type 2 diabetes (T2D) is a complex polygenic disease with unclear mechanism. In an attempt to identify novel genes involved in β-cell function, we harness a bioinformatics method called Loss-of-function tool (LoFtool) gene score. METHODS: RNA-sequencing data from human islets were used to cross-reference genes within the 1st quartile of most intolerant LoFtool score with the 100th most expressed genes in human islets. Out of these genes, GNAS and EEF1A1 genes were selected for further investigation in diabetic islets, metabolic tissues along with their correlation with diabetic phenotypes. The influence of GNAS and EEF1A1 on insulin secretion and β-cell function were validated in INS-1 cells. RESULTS: A comparatively higher expression level of GNAS and EEF1A1 was observed in human islets than fat, liver and muscle tissues. Furthermore, diabetic islets displayed a reduced expression of GNAS, but not of EEF1A, compared to non-diabetic islets. The expression of GNAS was positively correlated with insulin secretory index, GLP1R, GIPR and inversely correlated with HbA1c. Diabetic human islets displayed a reduced cAMP generation and insulin secretory capacity in response to glucose. Moreover, siRNA silencing of GNAS in INS-1 cells reduced insulin secretion, insulin content, and cAMP production. In addition, the expression of Insulin, PDX1, and MAFA was significantly down-regulated in GNAS-silenced cells. However, cell viability and apoptosis rate were unaffected. CONCLUSION: LoFtool is a powerful tool to identify genes associated with pancreatic islets dysfunction. GNAS is a crucial gene for the β-cell insulin secretory capacity.
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| 3. |
- Taneera, Jalal, et al.
(författare)
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Reduced Expression of Chl1 gene Impairs Insulin Secretion by Down-Regulating the Expression of Key Molecules of β-cell Function
- 2021
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Ingår i: Experimental and Clinical Endocrinology and Diabetes. - : Georg Thieme Verlag KG. - 0947-7349 .- 1439-3646. ; 129:12, s. 864-872
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Tidskriftsartikel (refereegranskat)abstract
- Silencing of Chl1 gene expression has been previously reported to reduce insulin secretion. Nevertheless, the mechanism underlying this effect remains unclear. In this study, we performed a serial of studies to investigate how Chl1 affects insulin secretion in INS-1 cells. RNA-sequencing was used to investigate the expression of CHL1 in human adipose, liver, muscle, and human islets. Silencing of Chl1 in INS-1 cells was done to assess its impact on the insulin secretion, content, cell viability, and apoptosis. In addition, gene set enrichment analysis (GSEA) was performed to identify possible molecular signatures that associate with Chl1 expression silencing. RNA sequencing data revealed a high expression of CHL1 in pancreatic islets and adipose tissues compared to liver and muscles tissues. Diabetic islets exhibited a lower expression of CHL1 as compared to non-diabetic islets. CHL1 expression was found to correlate positively with insulin secretory index, GLP1R but inversely with HbA 1cand BMI. Silencing of Chl1 in INS-1 cells markedly reduced insulin content and secretion. The expression of key molecules of β-cell function including Insulin, Pdx1, Gck, Glut2, and Insrβ was down-regulated in Chl1 -silenced cells at transcriptional and translational levels. Cell viability, apoptosis, and proliferation rate were not affected. GSEA showed that the insulin-signaling pathway was influenced in Chl1 -silenced cells. Silencing of Chl1 impairs β-cell function by disrupting the activity of key signaling pathways of importance for insulin biosynthesis and secretion.
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