Objective To investigate the effect of dual-specificity phosphatase 1/optical atrophy 1 (DUSP1/OPA1) signaling pathway on vascular smooth muscle cell (VSMC) calcification.Methods An in vitro model of VSMC calcification was induced by exposure to β-glycerophosphate and calcium chloride.VSMC calcification was assessed by Alizarin Red S staining and calcium content by ELISA.Apoptosis was detected by TUNEL.Western blotting was employed to determine the protein levels of DUSP1,OPA1,Runt-related transcription factor 2 (Runx-2),bone morphogenetic protein 2 (BMP-2),and cysteinyl aspartate-specific proteinase-3 (Caspase-3).The effects of DUSP1 overexpression and OPA1 knockdown on cell calcification were investigated.Results Calcium chloride and β-glycerolphosphate induced VSMC calcification and down-regulated the expression levels of DUSP1 (t=11.951,P<0.001) and OPA1 (t=8.487,P<0.001).DUSP1 overexpression promoted OPA1 expression (t=-8.921,P<0.001),attenuated VSMC calcification,reduced calcium content and apoptosis rate,and down-regulated the expression of Runx-2,BMP-2,and active Caspase-3 (all P<0.001).OPA1 knockdown increased calcium content and apoptosis rate,up-regulated the expression of Runx-2,BMP-2,and active Caspase-3,and promoted VSMC calcification (all P<0.001).Conclusion DUSP1 may inhibit the VSMC calcification through the OPA1 signaling pathway.