Basic-helix-loop-helix transcription factor DEC2 constitutes negative feedback loop in IFN-β-mediated inflammatory responses in human mesangial cells.

Differentiated embryo-chondrocyte 2 (DEC2), a basic-helix-loop-helix transcriptional factor, is involved in various biological reactions by regulating the expression of its target genes. In the present study, we demonstrated DEC2 expression in response to the treatment with polyinosinic-polycytidylic acid (poly IC), an authentic double-stranded RNA, in cultured human mesangial cells. RNA interference against DEC2 enhanced the poly IC-induced expression of IFN-β and its downstream genes, retinoic acid-inducible gene-I (RIG-I) and CCL5. Knockdown of TLR3 abolished the poly IC-induced DEC2 expression. DEC2 expression may constitute a negative feedback system for the IFN-β/RIG-I/CCL5 pathway in the glomerulus, which may play a role in controlling protracted inflammatory reactions in the kidney.