FSP1 promotes the biofunctions of adventitial fibroblast through the crosstalk among RAGE, JAK2/STAT3 and Wnt3a/β-catenin signalling pathways

Emerging evidence indicates that fibroblast-specific protein 1 (FSP1) provides vital effects in cell biofunctions. However, whether FSP1 influences the adventitial fibroblast (AF) and vascular remodelling remains unclear. Therefore, we investigated the potential role and action mechanism of FSP1-mediated AF bioactivity. AFs were cultured and stimulated with FSP1 and siRNA-FSP1 in vitro. Viability assays demonstrated that siRNA-FSP1 counteracted AFs proliferative, migratory and adherent abilities enhanced with FSP1. Flow cytometry revealed that FSP1 increased AFs number in S phase and decreased cellular apoptosis. Contrarily, siRNA-FSP1 displayed the contrary results. RT-PCR, Western blotting and immunocytochemistry showed that FSP1 synchronously up-regulated the expression of molecules in RAGE, JAK2/STAT3 and Wnt3a/beta-catenin pathways and induced a proinflammatory cytokine profile characterized by high levels of MCP-1, ICAM-1 and VCAM-1. Conversely, FSP1 knockdown reduced the expression of these molecules and cytokines. The increased number of autophagosomes in FSP1-stimulated group and fewer autophagic corpuscles in siRNA-FSP1 group was observed by transmission electron microscope (TEM). Autophagy-related proteins (LC3B, beclin-1 and Apg7) were higher in FSP1 group than those in other groups. Conversely, the expression of p62 protein was shown an opposite trend of variation. Therefore, these pathways can promote AFs bioactivity, facilitate autophagy and induce the expression of the proinflammatory cytokines. Contrarily, siRNA-FSP1 intercepts the crosstalk of these pathways, suppresses AF functions, restrains autophagy and attenuates the expression of the inflammatory factors. Our findings indicate that crosstalk among RAGE, STAT3/JAK2 and Wnt3a/beta-catenin signalling pathways may account for the mechanism of AF functions with the stimulation of FSP1.