An involvement of SR-B1 mediated p38 MAPK signaling pathway in serum amyloid A-induced angiogenesis in rheumatoid arthritis.

Serum amyloid A (SAA) has been reported high expression in autoimmune diseases, such as rheumatoid arthritis (RA). However, detailed molecular mechanisms induced by SAA in the pathogenesis of RA are still unclear. Herein, we focused on the role of SAA-SR-B1 mediated p38 MAPK signaling pathway in the process of RA angiogenesis. Our results showed that both SAA and SR-B1 predominantly localized to vascular endothelial cells, lining and sublining layers in RA synovium. In a series of in vitro experiments with human umbilical vein endothelial cells (HUVECs), SAA induced the endothelial cells (ECs) proliferation, migration and tube formation. However, blockage of SR-B1 and p38 MAPK inhibited SAA-induced cells proliferation, migration and tube formation. In conclusion, our data showed a possible molecular mechanism for SAA-SR-B1 induced angiogenesis events via p38 MAPK signaling pathway.