The Effect Of Cotl1on Nonalcoholic Fatty Liver Disease Development

Nonalcoholic fatty liver disease includes a series of histological abnormalities in the liver.Its pathological changes range from nonalcoholic fatty liver to nonalcoholic steatohepatitis,and then develop into hepatic fibrosis and cirrhosis.Seriously,it could lead to liver cancer.It is characterized by hepatocyte fat accumulation,vesicular steatosis,balloon hepatocyte,cell necrosis,inflammatory cell infiltration,and is closely related to obesity,diabetes and other metabolic syndrome diseases.At present,the number of NAFLD is increasing day by day,which is the most common cause of chronic liver disease in children and adults in the world,and the global prevalence rate is as high as 25%.In the early stage of the experiment,a candidate protein COTL1 molecule was screened from the differential proteome of NAFLD mouse model induced by methionine cho line deficiency diet,and it was verified that COTL1 might be involved in the occurrence and development of NAFLD.COTL1 molecule is a highly homologous protein of F-actin binding protein.At present,the function of COTL1 molecule has not been deeply studied.There are no reports on the relationship between COTL1 and the occurrence and development of NAFLD.In this study,we established an animal model of NAFLD by constructing liver cell-specific COTL1 knockout mice to explore the mechanism of COTL1 in the occurrence and development of NAFLD.Objective:(1)to confirm the promoting effect of COTL1 on the occurrence and development of NAFLD;(2)to determine which cells in the liver have the function of promoting the occurrence and development of NAFLD;(3)to determine the mechanism by which COTL1 affects the occurrence and development of NAFLD.Through this study,we will deepen the molecular function of COTL1 and its mechanism affecting the occurrence and development of NAFLD,and may open up new therapeutic targets and strategies for the prevention and treatment of NAFLD.Methods:(1)NAFLD mouse model was induced by MCD diet.The expression of COTL1 in liver was down-regulated by adeno-associated virus vector,and the effect of liver-specific COTL1 knockdown on NAFLD was detected.(2)The liver Kupffer cell(KCs)specific COTL1 knockout mice were established by Cre-lox P system.The NAFLD mouse model was induced by high fat diet(HFD),and the phenotype,serum biochemical indexes,pathological sections and fatty acid metabolism of the mice was detected to conform the effect of liver KCs-specific COTL1 knockout mice on the occurrence and development of NAFLD.(3)The liver sinusoidal endothelial cell(LSECs)specific COTL1 knockout mice were established by Cre-lox P system,and the NAFLD mouse model was induced by high fat diet.The effect of liver LSECs-specific COTL1 knockout on the occurrence and development of NAFLD was detected.Results:(1)NAFLD mouse model was successfully induced by MCD diet,and the expression of COTL1 was increased in the liver of NAFLD model mice induced by MCD diet.(2)Liver specific COTL1 knockout mice increased body weight,increased serum transaminase level,decreased lipid droplets,decreased liver fat accumulation and alleviated hepatic steatosis.(3)NAFLD mouse model was successfully induced by HFD diet,and the expression of COTL1 was increased in the liver of NAFLD mice induced by HFD.(4)The expression of COTL1 in Hepatocytes of NAFLD model mice was increased.(5)Liver KCs specific COTL1 knockout mice were successfully constructed.Compared with the control mice,the body weight and liver weight of KCs-specific COTL1 knockout mice induced by high-fat diet were significantly decreased,the levels of serum transaminase,Serum lipid and cholesterol were decreased,the synthesis of fatty acids was decreased,and the oxidation was significantly increased.The level of cytokines and inflammatory factors decreased,the accumulation of liver fat was significantly reduced,the vacuoles of lipid droplets decreased,and the degree of hepatic steatosis was significantly reduced.(6)Liver LSECs-specific COTL1 knockout mice were successfully constructed.Induced by high-fat diet,the body weight and liver weight of LSECs-specific COTL1 knockout mice decreased,the level of ALT transaminase decreased significantly,liver injury alleviated,liver volume decreased,lipid droplet aggregation decreased,fat accumulation improved,and steatosis alleviated.(7)The expression of COTL1 interacting molecule ALOX5 was down-regulated with the decrease of COTL1 expression level.Conclusion: The expression of COTL1 is up-regulated in the liver of NAFLD model mice induced by MCD diet and high-fat diet.Specific knockdown of liver COTL1 expression can reduce hepatic steatosis,COTL1 can promote the occurrence and development of NAFLD.It was found for the first time that both KCs-specific and LSECs-specific knockout COTL1 could significantly reduce hepatic steatosis and slow down the development of simple steatosis to steatohepatitis.The mechanism of COTL1 may be related to ALOX5 and the promoting effect of COTL1 on NAFLD may be regulated by liver parenchymal cells and non-parenchymal cells.