Functional study of the upregulation of miRNA-27a and miRNA-27b in 3T3-L1 cells in response to berberine.

Berberine is the major active component of Rhizoma Coptidis derived from a traditional Chinese herbal medicine and is known to regulate micro (mi)RNA levels, although the mechanism for this action remains unknown. The present study confirmed that treatment of 3T3‑L1 cells with berberine inhibited cell viability and differentiation in a dose‑ and time‑dependent manner, and significantly increased the mRNA expression levels of miRNA‑27a and miRNA‑27b. In addition, in 3T3‑L1 cells treated with berberine, overexpression of miRNA‑27a and miRNA‑27b improved the berberine-mediated inhibition of cell differentiation and reduction of triglyceride contents. By contrast, miRNA‑27a and miRNA‑27b inhibitors attenuated the berberine‑mediated inhibition of cell differentiation and reduction of triglyceride contents. Additionally, peroxisome proliferator‑activated receptors (PPAR)‑γ was confirmed to be a target of miRNA‑27a in the 3T3‑L1 cells. A dual‑luciferase reporter assay indicated that the expression of PPAR‑γ was negatively regulated by miRNA-27a. These findings may provide novel mechanistic insight into the antiobesity effects of certain compounds in traditional Chinese herbal medicine.