Intravenous injection of microvesicle-delivery miR-130b alleviates high-fat diet-induced obesity in C57BL/6 mice through translational repression of PPAR-γ.

BACKGROUND: We have shown previously that microvesicle (MV)-delivered miR-130b (miR-130b-MV) is able to target PPAR-γ and subsequently reduce the lipid accumulation in vitro. However, the in vivo effect of miR-130b on fat deposition and glucose homeostasis remains unknown. RESULTS: Three-week-old C57BL/6 mice were fed a high-fat diet for 8 weeks and then intravenously injected with MV-packaged scrambled control microRNA (miRNA) or miR-130b every other day for 10 days. Glucose tolerance test was performed and body weight, epididymal fat weight, as well as the expression of lipid metabolic genes were determined. We showed that mice fed on high-fat diet for 8 weeks demonstrated significantly higher body weight, elevated blood glucose and impaired glucose tolerance. miR-130b-MV injection significantly reduced body weight and epididymal fat weight and partly restored glucose tolerance. miR-130b expression was significantly increased in the epididymal fat after miR-130b-MV injection while the protein content of its target gene PPAR-γ was significantly suppressed, together with a significant up-regulation of the lipolysis genes, hormone sensitive lipase, monoglyceride lipase and leptin. Moreover, miR-130b-MV injection increased the expression of miR-378a and miR-378-3p that are reported to participate in the regulation of fat deposition. CONCLUSION: Our results indicate that miR-130b-MV is able to reduce the epididymal fat deposition and partly restore glucose tolerance, through translational repression of PPAR-γ in a high-fat diet-induced obese mouse model.