Ginsenoside-Rb₁ Promotes Adipogenesis Through Regulation of PPARγ and MicroRNA-27b

Abstract

Ginsenoside-Rb₁ (Rb₁), one of the bioactive components in ginseng extract, is recently reported to be able to promote adipogenesis and peroxisome proliferator-activated receptor gamma (PPARγ) expression. Meanwhile, microRNA-27b (miR-27b) is also identified to regulate adipogenesis by targeting PPARγ2. In the present study, we attempted to link up the Rb₁-promoted adipogenesis with PPARγ binding and miR-27b regulation. First, we demonstrated that GW9662, an antagonist of PPARγ, could block Rb₁-induced 3T3-L1 differentiation with little toxicity towards cell proliferation. Then, expression levels for both of miR-27b and its primary transcript, pri-mir-27b, were found to decrease upon Rb₁ treatment. Again, GW9662 could attenuate the inhibitory effect of Rb₁ on both miR-27 and pri-mir-27b expression. Since Rb₁ was demonstrated to have binding activity towards PPARγ, we thus speculate that Rb₁ may act though PPARγ to downregulate mir-27b gene transcription and mature miR-27b activity, which in turn promotes PPARγ expression and adipogenesis. Enhancement on adipogenesis of adipose tissues is expected to prevent lipotoxicty in nonadipose tissues. Our data may give a better illustration to explain the antidiabetic effect of Rb₁ and provide a hint on treatment of lipid related metabolic diseases in the future.

Key words

ginsensoside-Rb₁ - PPARγ - adipogenesis - miR-27b - 3T3-L1 adipocytes

*

^*  These authors contributed equally to this manuscript.

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