Macrophage-specific promoter SP146-C1 enhances vascular endothelial growth factor C expression in atherosclerotic mice

Li Sijin; Feng Xiaoteng; Wang Yiru; Liu Ping

doi:10.12307/2024.392

Abstract：BACKGROUND:The expression efficiency of recombinant adeno-associated virus serotype 9(rAAV9)carrying the macrophage-specific promoter synthetic promoter 146-C1(SP146-C1)and the exogenous gene vascular endothelial growth factor C(VEGFC)in atherosclerosis is uncertain. OBJECTIVE:To investigate the expression efficiency of rAAV9-SP146-C1-VEGFC in atherosclerotic mice and its effect on lymphangiogenesis. METHODS:Thirty ApoE-/-mice were fed high-fat diet for 12 weeks to establish atherosclerosis models and were randomly divided into six groups,five in each group:7-,14-,21-,28-,and 35-day transfection groups and control group.The mice in the transfection groups were transfected with 5.0×1011 vg rAAV9-SP146-C1-VEGFC by caudal vein injection.In the control group,the mice were injected with the same amount of control virus rAAV9-SP146-C1-Scramble.Animals in the first five groups were killed under anesthesia at 7,14,21,28 and 35 days after transfection,respectively,and those in the control group were killed under anesthesia at 7 days.Serum,femur,tibia,heart and aorta tissue samples were collected and retained in each group.The femur and tibia of mice in each group were used to extract bone marrow-derived macrophages.The gene expression of vascular endothelial growth factor C(VEGFC),vascular endothelial growth factor receptor 3(VEGFR3),Podoplanin and lymphatic vessel endothelial hyaluronan receptor-1(LYVE-1)in bone marrow-derived macrophages and the aorta were detected by RT-qPCR.VEGFC protein expression levels in bone marrow-derived macrophages and the aorta were detected by western blot,serum level of VEGFC was detected by ELISA,and VEGFC expression in the aortic sinus and LYVE-1 expression around the aorta and in the myocardium was detected by immunofluorescence. RESULTS AND CONCLUSION:The serum level of VEGFC,the mRNA expression of VEGFC,VEGFR3,Podoplanin,and LYVE-1 in bone marrow-derived macrophages and the aorta,the protein expression of VEGFC in bone marrow-derived macrophages,and the fluorescence intensity of VEGFC in aortic sinus plaques were significantly increased in the 7-day transfection group compared with the control group(P＜0.05,P＜0.01).Serum VEGFC level of mice transfected with rAAV9-SP146-C1-VEGFC gradually increased with time and began to decrease at 28 days.mRNA levels of VEGFC,VEGFR3,Podoplanin and LYVE-1 in mouse aorta and bone marrow-derived macrophages,VEGFC protein level in bone marrow-derived macrophages,VEGFC fluorescence intensity in aortic sinus plaques,LYVE-1 fluorescence intensity around the aortic sinus and in the myocardium gradually increased with time(P＜0.05).In addition,the mRNA level of LYVE-1 in the aorta and the fluorescence intensity of LYVE-1 around the aortic sinus and in the myocardium were the highest at 28 days(P＜0.05),and gradually decreased(P＜0.05).The expression of the other indicators reached the peak at 21 days.To conclude,rAAV9-SP146-C1-VEGFC could effectively transfect bone marrow-derived macrophages and promote lymphatic hyperplasia in atherosclerotic mice.