SET8，a novel regulator to ameliorate vascular calcification via activating PI3K/Akt mediated anti-apoptotic effects.

Previous studies have showed that the apoptosis of vascular smooth muscle cells (VSMCs) underlies the mechanism of pathological calcifications in patients with chronic kidney disease (CKD). SET domain-containing protein 8 (SET8), as an efficient protein has been reported to modulate cell apoptosis in hepatocellular carcinoma cell, esophageal squamous cell and neuronal cell through regulating pathological processes, such as cell-cycle progression and transcription regulation. However, whether SET8 is involved in high phosphorus induced vascular calcification by mediating apoptosis remains undefined. Here, we reported that SET8 was located both in nucleus and cytoplasm, and significantly downregulated in calcification models. SET8 deficiency promoted the apoptosis of VSMCs, which was indicated by the increased Bax/Bcl-2 and cleaved caspase-3/total caspase-3 ratios. Mechanistically, PI3K/Akt pathway was mediated by SET8 and inhibition of PI3K/Akt signaling pathway by giving LY294002 or transfecting Akt phosphorylation inactivated mutation plasmid increased apoptosis and calcification. Akt phosphorylation constitutively activated mutation could reduce apoptosis and calcification of VSMCs. Furthermore, exogenous overexpression of SET8 could reverse the effect of PI3K/Akt inhibition on the apoptosis and calcification of VSMCs. In summary, our researches suggested that SET8 overexpression ameliorated high phosphorus induced calcification of vascular smooth muscle cells via activating PI3K/Akt mediated anti-apoptotic effects.