Abstract: Objective To investigate the role of Toll-like receptor 4 (TLR4) signaling pathway in the activation of renninangiotensin
system (RAS) in adipose cells. Methods 3T3-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 traslocation of NF-κB p65 subunit in the cells. Results Stimulation 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. Conclusion
Activation of TLR4 signaling pathway may trigger the activation of local RAS in adipose cells.