Fig. 5. A schematic view of the model investigated in this study.

ATF4 activates FGF21 transcription by binding to its promoter in the nuclei of HASMCs. Increased FGF21 mRNA levels leads to the upregulation of FGF21 protein expression, which promotes proliferation, migration and phenotype switch of HASMCs. ATF4, activating transcription factor 4; HASMCs, human aortic vascular smooth muscle cells; FGF21, fibroblast growth factor 21.