Open AccessmiR-29a Negatively Affects Glucose-Stimulated Insulin Secretion and MIN6 Cell Proliferation via Cdc42/β-Catenin Signaling
Author(s) -
Jing Duan,
Xiaoqin Qian,
Jun Li,
Xiangyu Xiao,
Xiangtong Lu,
Lin-Chen Lv,
Qing-Yun Huang,
Wen Ding,
Hongyan Zhang,
Likuan Xiong
Publication year - 2019
Publication title -
international journal of endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.875
H-Index - 60
eISSN - 1687-8345
pISSN - 1687-8337
DOI - 10.1155/2019/5219782
Subject(s) - medicine , cdc42 , catenin , secretion , insulin , endocrinology , microbiology and biotechnology , cancer research , signal transduction , wnt signaling pathway , biology
Background Diabetes is a progressive metabolic disease characterized by hyperglycemia. Functional impairment of islet β cells can occur to varying degrees. This impairment can initially be compensated for by proliferation and metabolic changes of β cells. Cell division control protein 42 (Cdc42) and the microRNA (miRNA) miR-29 have important roles in β -cell proliferation and glucose-stimulated insulin secretion (GSIS), which we further explored using the mouse insulinoma cell line MIN6.Methods Upregulation and downregulation of miR-29a and Cdc42 were accomplished using transient transfection. miR-29a and Cdc42 expression was detected by real-time PCR and western blotting. MIN6 proliferation was detected using a cell counting kit assay. GSIS under high-glucose (20.0 mM) or basal-glucose (5.0 mM) stimulation was detected by enzyme-linked immunosorbent assay. The miR-29a binding site in the Cdc42 mRNA 3′-untranslated region (UTR) was determined using bioinformatics and luciferase reporter assays.Results miR-29a overexpression inhibited proliferation ( P < 0.01) and GSIS under high-glucose stimulation ( P < 0.01). Cdc42 overexpression promoted proliferation ( P < 0.05) and GSIS under high-glucose stimulation ( P < 0.05). miR-29a overexpression decreased Cdc42 expression ( P < 0.01), whereas miR-29a downregulation increased Cdc42 expression ( P < 0.01). The results showed that the Cdc42 mRNA 3′-UTR is a direct target of miR-29a in vitro . Additionally, Cdc42 reversed miR-29a-mediated inhibition of proliferation and GSIS ( P < 0.01). Furthermore, miR-29a inhibited β -catenin expression ( P < 0.01), whereas Cdc42 promoted β -catenin expression ( P < 0.01).Conclusion By negatively regulating Cdc42 and the downstream molecule β -catenin, miR-29a inhibits MIN6 proliferation and insulin secretion.