Correlation between insulin-induced estrogen receptor methylation and atherosclerosis.
Hyperinsulinemia and insulin resistance have been recently recognized as an important cause of atherosclerosis. Clinical studies have also found that expression of the estrogen receptor is closely related to the incidence of atherosclerosis. This study investigate the effects of insulin and estrogen receptor α (ER-α) in atherosclerosis.



Double knockout ApoE/Lepr mice were given intraperitoneal injections of insulin, and their aortae were harvested for hematoxylin-eosin staining and immunohistochemical analysis. In addition, vascular smooth muscle cells (VSMCs) were treated with insulin or infected with a lentivirus encoding exogenous ER-α, and changes in gene expression were detected by real-time polymerase chain reaction and western blotting. The methylation levels of the ER-α gene were tested using bisulfite sequencing PCR, and flow cytometry and EdU assay were used to measure VSMCs proliferation.



Our results showed that insulin can induce the formation of atherosclerosis. Gene expression analysis revealed that insulin promotes the expression of DNA methyltransferases and inhibits ER-α expression, while 5-aza-2'-deoxycytidine can inhibit this effect of insulin. Bisulfite sequencing PCR analysis showed that methylation of the ER-α second exon region increased in VSMCs treated with insulin. The results also showed that ER-α can inhibit VSMCs proliferation.



Our data suggest that insulin promotes the expression of DNA methyltransferases, induces methylation of ER-α second exon region and decreases the expression of ER-α, thereby interfering with estrogen regulation of VSMCs proliferation, resulting in atherosclerosis.
Department of Cardiology, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
Jia
J
Min
Department of Cardiology, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
Zhong
Z
Weitian
Department of Cardiology, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
Cai
C
Peng
Department of Cardiology, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
Peng
P
Yan
Department of Medical Genetics, College of Basic Medicine, Third Military, Medical University, Chongqing, 400038, China.
Zhang
Z
Bo
Department of Medical Genetics, College of Basic Medicine, Third Military, Medical University, Chongqing, 400038, China.
Wang
W
Yan
Department of Medical Genetics, College of Basic Medicine, Third Military, Medical University, Chongqing, 400038, China. baiyungene@gmail.com.
Bai
B
Yun
Department of Cardiology, Daping Hospital, Third Military Medical University, Chongqing, 400042, China. wangxuk@163.com.
Wang
W
Xukai
D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D001018:Aortic Diseases / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D001057:Apolipoproteins E / Q000172:deficiency / Q000235:genetics; D050197:Atherosclerosis / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D019175:DNA Methylation; D004195:Disease Models, Animal; D047628:Estrogen Receptor alpha / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D005091:Exons; D005260:Female; D020022:Genetic Predisposition to Disease; D007328:Insulin / Q000633:toxicity*; D018345:Mice, Knockout; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D010641:Phenotype; D051381:Rats; D054411:Receptors, Leptin / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014162:Transfection
D001057:Apolipoproteins E; D047628:Estrogen Receptor alpha; D007328:Insulin; D054411:Receptors, Leptin
DNA methylation; Epigenetics; Estrogen receptor (ER); Insulin; VSMC