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-Rb
1
- PPARγ - adipogenesis - miR-27b - 3T3-L1 adipocytes
