Rosiglitazone negatively regulates c-Jun N-terminal kinase and toll-like receptor 4Â proinflammatory signalling during initiation of experimental aortic aneurysms

ObjectiveDevelopment and rupture of aortic aneurysms (AA) is a complex process involving inflammation, cell death, tissue and matrix remodelling. The thiazolidinediones (TZDs) including Rosiglitazone (RGZ) are a family of drugs which act as agonists of the nuclear peroxisome proliferator-activated receptors and have a broad spectrum of effects on a number of biological processes in the cardiovascular system. In our previous study we have demonstrated that RGZ has a marked effect on both aneurysm rupture and development, however, the precise mechanism of this is unknown.Methods and resultsIn the present study, we examined possible targets of RGZ action in the early stages of Angiotensin II-induced AA in apolipoprotein E-deficient mice. For this purpose we employed immunoblotting, ELISA and antibody array approaches. We found that RGZ significantly inhibited c-Jun N-terminal kinase (JNK) phosphorylation and down-regulated toll-like receptor 4 (TLR4) expression at the site of lesion formation in response to Angiotensin II infusion in the initiation stage (6-72 h) of experimental AA development. Importantly, this effect was also associated with a decrease of CD4 antigen and reduction in production of TLR4/JNK-dependant proinflammatory chemokines MCP-1 and MIP-1α.ConclusionThese data suggest that RGZ can modulate inflammatory processes by blocking TLR4/JNK signalling in initiation stages of AA development.

► Rosiglitazone has a marked effect on both aneurysm rupture and development. ► Rosiglitazone modulates inflammation by blocking TLR4/JNK signalling. ► Specific antagonists of JNK and TLR4 may be therapeutic for aneurysms.