RESUMEN
Vascular calcification is commonly observed in chronic kidney disease. The mechanism of how the calcification signal from endothelial cells is transmitted to vascular smooth muscle cells (VSMCs) remains unknown. The aim of the present study was to investigate whether exosomes from HUVECs (HUVECExos) could regulate VSMC calcification and its potential signaling pathway. HUVECExos were isolated from HUVECs under no phosphorus (NP) and high phosphorus (HP) conditions. Alizarin Red S staining and calcium (Ca) content analysis were carried out to detect calcification in VSMCs. Proteomics analysis was carried out to detect the differential expression of exosomal proteins. Protein and mRNA levels were measured by western blot analysis and reverse transcriptionquantitative PCR (RTqPCR). Exosomes derived from HPHUVECs promoted the calcification of VSMCs, as assessed by Alizarin Red S staining, alkaline phosphatase activity assays, Ca content measurements and the increased expression of runtrelated transcription factor 2 and osteopontin. Proteomic analysis detected the upregulation of STAT1 in HPexosomes from HUVECs (HUVECExos) compared with NPHUVECExos, which was also confirmed by western blot analysis and RTqPCR. Inhibition of STAT1 expression in VSMCs using fludarabine or knockdown of STAT1 expression using small interfering RNA alleviated the calcification of VSMCs. Furthermore, lithium chloride (Wnt activator) reversed the protective effect of STAT1 inhibition on VSMC calcification, while Dickkopf1 (Wnt inhibitor) exerted the opposite effect, suggesting that activation of the Wnt/ßcatenin signaling pathway was involved in STAT1mediated VSMC calcification. In conclusion, the present results indicated that exosomal STAT1 derived from HPtreated HUVECs could promote VSMC calcification, and activation of the Wnt/ßcatenin pathway may be a potential mechanism of the VSMC calcification promoted by exosomes.