Jagged1 knocking down in endothelial cells accelerates PDGF induced proliferation and migration of vascular smooth muscle cells in rats

AIM:To investigate the effect of Jagged1 expression in endothelial cells(EC)on platelet derived growth factor(PDGF)induced proliferation and migration of vascular smooth muscle cells(VSMC)in rat.METHODS:Rat aorta EC was inoculated in the lower chamber and VSMC were in the upper chamber of the cell coculture system.Three groups were divided:control,sicontrol and siJagged1.The EC Jagged1 protein expression was assayed by Western blotting to evaluate small RNA interfering(RNAi)efficiency.After the cells were cocultured with PDGF for 24 h,the proliferation and migration of VSMC were respectively evaluated by [3H]-TdR incorporation and migrating cells counting.Protein expression of α-SM-actin in VSMC was assayed by Western blotting.RESULTS:The Jagged1 protein expression in EC was significantly lower in siJagged1 group than that in control group(0.26±0.02 vs 0.67±0.02,P0.05),and no statistic significance was observed between control and sicontrol groups.The VSMC [3H]-TdR incorporation and migration were higher in PDGF +siJagged1 group than those in PDGF group [3H]-TdR incorporation(23 074±2 702)counts·min-1·well-1 vs(16 442±1 803)counts·min-1·well-1,n=5,P0.05;migration(27±4)cells/field vs(15±3)cells/field,n=5,P0.05.The α-SM-actin protein in VSMC was lower in PDGF + siJagged1 group than that in PDGF group(0.25±0.06 vs 0.49±0.04,n=3,P0.05).CONCLUSION:Jagged1 knock down in rat EC accelerates PDGF induced proliferation and migration of VSMC.These results suggest that Jagged1 expression in EC plays an important role in maintaining VSMC contract phenotype and inhibiting VSMC overgrowth after arterial injury.