OBJECTIVETo investigate the role of Toll-like receptor 4 (TLR4) signaling pathway in the activation of rennin- angiotensin system (RAS) in adipose cells.

METHODS3T3-L1 cells induced with isobutylmethylxanthine, insulin and dexamethasone to differentiate into adipocytes were stimulated by LPS with or without irbesartan pretreatment. The expression levels of TLR4, angiotensinogen (AGT) and angiotensin II receptor type 1 (ATlR) mRNA in 3T3-L1 cells was determined by RT-PCR, and their protein expressions were detected with Western-blotting. Immunofluorescence double staining was used to observe the translocation of NF-κB p65 subunit in the cells.

RESULTSStimulation with LPS dose- and time-dependently increased the mRNA and protein expressions of TLR4, AGT and AT1R. LPS exposure resulted in enhanced translocation of NF-κB p65 subunit in the adipose cells, which was attenuated by irbesartan pretreatment.

CONCLUSIONActivation of TLR4 signaling pathway may trigger the activation of local RAS in adipose cells.