Chemerin-induced angiogenesis and adipogenesis in 3 T3-L1 preadipocytes is mediated by lncRNA Meg3 through regulating Dickkopf-3 by sponging miR-21

Purpose: Obesity is often caused by the excess adipogenesis and regulated by long non-coding RNAs (lncRNAs) and microRNAs (miRNAs). We performed this study to investigate the influence of Meg3 expression on adipogenesis and also the Meg3/miR-217/Dkk3 axis-mediated molecular mechanism in adipogenesis and angiogenesis. Methods: 3 T3-L1 preadipocytes were incubated with chemerin and transfected with Meg3-overexpressing (OE-Meg3) and Dkk3-overexpressing (OE-Dkk3) plasmids, siRNAs, and miR-217 mimics, inhibitor and scrambled sequences for 48 h or 72 h. The changes in cell proliferation, adipogenesis and angiogenesis ability in 3 T3-L1 preadipocytes was detected by using the corresponding assay. The expressions of related proteins were detected via western blot. Results: Chemerin decreased miR-217 expression and increased Meg3 expression, meanwhile promoted the proliferation, adipogenesis and angiogenesis in 3 T3-L1 preadipocytes. Besides, OE-Meg3 exerted the synergistic effect on 3 T3-L1 preadipocytes when co-treated with chemerin. The target interactions between Meg3 and miR-217 as well as between miR-217 and Dkk3 were validated using dual-luciferase reporter system. SiMeg3 antagonized chemerin-induced changes, while the addition of miR-217 inhibitor attenuated siMeg3-induced changes in 3 T3-L1 preadipocytes. The proliferation, adipogenesis and angiogenesis in 3 T3-L1 preadipocytes were suppressed by miR-217 mimics, while promoted by the OE-Dkk3 Chemerin promoted the expression of fatty acid binding protein 4 and vascular endothelial growth factor (VEGF) proteins, and decreased the expression of cyclin D1, c-Myc, and beta-catenin proteins. Meanwhile, these effects were further enhanced by OE-Meg3 or OE-Dkk3. However, the transfection of siMeg3, or miR-217 mimics, or siDkk3 reversed the previous changes. Conclusions: Meg3/miR-217/Dkk3 induced adipogenesis and angiogenesis in 3 T3-L1 preadipocytes via activating VEGF signaling pathway and inhibiting Wnt/beta-catenin signaling pathway.