Multiple studies have reported different methods in treating gestational diabetes mellitus (GDM); however, the relationship between miR-335-5p and GDM still remains unclear. Here, this study explores the effect of miR-335-5p on insulin resistance and pancreatic islet β-cell secretion via activation of the TGFβ signaling pathway by downregulating VASH1 expression in GDM mice. The GDM mouse model was established and mainly treated with miR-335-5p mimic, miR-335-5p inhibitor, si-VASH1, and miR-335-5p inhibitor + si-VASH1. Oral glucose tolerance test (OGTT) was conducted to detect fasting blood glucose (FBG) fasting insulin (FINS). The OGTT was also used to calculate a homeostasis model assessment of insulin resistance (HOMA-IR). A hyperglycemic clamp was performed to measure the glucose infusion rate (GIR), which estimated β-cell function. Expressions of miR-335-5p, VASH1, TGF-β1, and c-Myc in pancreatic islet β-cells were determined by RT-qPCR, western blot analysis, and insulin release by ELISA. The miR-335-5p mimic and si-VASH1 groups showed elevated blood glucose levels, glucose area under the curve (GAUC), and HOMA-IR, but a reduced GIR and positive expression of VASH1. Overexpression of miR-335-5p and inhibition of VASH1 contributed to activated TGFβ1 pathway, higher c-Myc, and lower VASH1 expressions, in addition to downregulated insulin and insulin release levels. These findings provided evidence that miR-335-5p enhanced insulin resistance and suppressed pancreatic islet β-cell secretion by inhibiting VASH1, eventually activating the TGF-β pathway in GDM mice, which provides more clinical insight on the GDM treatment. K E Y W O R D S gestational diabetes mellitus, insulin resistance, microRNA-335-5p, pancreatic islet β-cell secretion, TGF-β pathway, VASH1
Background: Long non-coding RNAs (lncRNAs) have been illustrated to contribute to the development of gestational diabetes mellitus (GDM). In the present study, we aimed to elucidate how lncRNA taurine upregulated gene 1 (TUG1) influences insulin resistance (IR) in a high-fat diet (HFD)-induced mouse model of GDM. Methods: We initially developed a mouse model of HFD-induced GDM, from which islet tissues were collected for RNA and protein extraction. Interactions among lncRNA TUG1/microRNA (miR)-328-3p/sterol regulatory element binding protein 2 (SREBP-2) were assessed by dual-luciferase reporter assay. Fasting blood glucose (FBG), fasting insulin (FINS), homeostasis model assessment of insulin resistance (HOMA-IR), HOMA pancreatic β-cell function (HOMA-β), insulin sensitivity index for oral glucose tolerance tests (ISOGTT) and insulinogenic index (IGI) levels in mouse serum were measured through conducting gain-and loss-of-function experiments. Results: Abundant expression of miR-328 and deficient expression of lncRNA TUG1 and SREBP-2 were characterized in the islet tissues of mice with HFD-induced GDM. LncRNA TUG1 competitively bound to miR-328-3p, which specifically targeted SREBP-2. Either depletion of miR-328-3p or restoration of lncRNA TUG1 and SREBP-2 reduced the FBG, FINS, HOMA-β, and HOMA-IR levels while increasing ISOGTT and IGI levels, promoting the expression of the extracellular signal-regulated kinase (ERK) signaling pathway-related genes, and inhibiting apoptosis of islet cells in GDM mice. Upregulation miR-328-3p reversed the alleviative effects of SREBP-2 and lncRNA TUG1 on IR. Conclusion:Our study provides evidence that the lncRNA TUG1 may prevent IR following GDM through competitively binding to miR-328-3p and promoting the SREBP-2-mediated ERK signaling pathway inactivation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.