The Study Of HCMV-Encoded IE2 Effect On Glucose And Lipid Metabolism In Transgenic Mice

Objective: Domestic and international studies have confirmed that HCMV infection is a major risk factor for atherosclerosis(AS),and HCMV infection is also associated with disorders of glucose and lipid metabolism,such as coronary heart disease,obesity and type 2 diabetes.Several studies have shown that HCMV infection induces lipid production by activating the expression of sterol regulatory element binding protein 1c(SRBP1c).SREBP1 c plays a key role in the development of hepatic steatosis in nonalcoholic fatty liver disease(NAFLD).Recent studies have shown that human cytomegalovirus(HCMV)infection may play a role in the pathogenesis of NAFLD metabolic diseases,but it is unclear whether HCMV-encoded IE2 plays an important role in this process.In recent decades,studies on the mechanism of abnormal lipid metabolism caused by HCMV infection have been conducted mainly at the cellular level in vitro,and have rarely been studied in vivo.In this study,due to the high species specificity of HCMV,we firstly established that UL122 genetically modified mice models that can steadily and continuously express IE2 protein to overcome species-specific diseases.Secondly,we further studied that the IE2 effect on the expression levels of SREBP1 c and on lipid metabolism in the liver of UL122 genetically modified mice.Methods: jUL122 genetically modified mice models that can steadily and continuously express IE2 protein were established.k The establishment of UL122 genetically modified mice was identified by PCR technology.Then,the mice were divided into the experimental group(positive mice identified)and the control group(wild-type mice,n = 16 per group).l Measure the body weight of the mice,take blood from the eyelids,collect serum,and detect the content of clinical glucose and lipid metabolism indicators such as FPG,TG,TC,LDL,HDL.mThe triglyceride content in their livers was measured using a colorimetric assay.n Oil red O-stain method was used to analyze the condition of lipids in liver tissue.oHE staining was used to observe the effect of IE2 on liver tissue structure.pReal-time quantitative PCR was used to detect the expression of SREBP1 c mRNA and IE2 mRNA in the liver of the experimental group.qImmunohistochemistry were performed to detect the expression and distribution of IE2 and SREBP1 c in liver tissue.Results: jPCR results indicate the success of modeling of UL122 transgenic mice.k From 30 weeks,the body weight of the experimental group was significantly higher than that of the control group,and it was statistically significant(P<0.05).The concentration of fasting blood glucose(FPG)and triglyceride(TG)in the experimental group and the control group.There was a significant difference(P<0.05).There was a significant difference(P<0.05).There was no significant difference in total cholesterol(TC),low-density lipoprotein(LDL)and high-density lipoprotein(HDL),and there was no statistical significance(P>0.05).lColorimetric assay results showed that compared with the control group,the content of triglyceride in the experimental group was significantly increased in the experimental group(P<0.05).mOil red O-staining results showed that compared with the control group,the lipid droplets were large and significantly accumulated in the liver tissue of the experimental nHE staining results showed that compared with the control group,the liver tissue structure of the experimental group was disordered,fat vacuoles appeared,and the liver o Real-time Quantitative PCR showed that the level of SREBP1 c mRNA in the liver of the experimental group was significantly higher than the control group(P<0.05).Meanwhile,in the experimental group,SREBP1 c was positively correlated with IE2 at the mRNA level,and the content of SREBP1 c mRNA level increased with the increase of IE2 mRNA level.pImmunohistochemistry results showed that IE2 was positive in the liver of the experimental group and negative in the nucleus of the control group.The expression of SREBP1 c in the liver of the experimental group was significantly increased(P<0.001).Conclusions:In UL122 transgenic mice,the body weight,fasting blood glucose(FPG),and triglyceride(TG)content of mice were higher than wild-type wild C57BL/6 mice.The expression of SREBP1 c was significantly increased in UL122 transgenic mice,and its overexpression in the liver cells can promote triglyceride accumulation and hepatic steatosis.Taken together,our data collectively demonstrate that HCMV infection is highly associated with NAFLD,SREBP1 c overexpression promotes hepatic steatosis,and this up-regulation is most likely mediated by IE2.Therefore,the establishment of the UL122 genetically modified mice model overcame species specificity,an innovation which will contribute to understanding the mechanisms of IE2 inducing diseases,as well as providing a theoretical basis for the prevention and treatment of some diseases.