TNFα-induced up-regulation of miR-155 inhibits adipogenesis by down-regulating early adipogenic transcription factors

Tumor necrosis factor alpha (TNF alpha) is known to inhibit adipogenesis, but the molecular mechanism of this inhibition remains elusive. In the present study, we found that TNF alpha-induced inhibition of adipogenesis mainly occurs when 3T3-L1 preadipocytes are treated with TNF alpha within 2 h induction of adipogenesis. We revealed that TNF alpha treatment results in the up-regulation of miR-155 through the NF kappa B pathway in 3T3-L1 cells. This overexpression of miR-155 may suppress the expression of C/EBP beta and CREB by directly targeting their 3' untranslated regions (3' UTRs). Importantly, anti-miR-155 reduces the TNF alpha-induced inhibition of adipogenesis, whereas exogenous expression of mir-155 inhibits adipogenesis. Taken together, these findings reveal a novel role for TNF alpha in the regulation of anti-adipogenic miRNAs. (C) 2011 Elsevier Inc. All rights reserved.