Study Of The Pathogenesis Of NAFLD

Part1Study of the effects of CAPON on the pathogenesis of NAFLDObjective To study the association of CAPON rs12742393single nucleotide polymorphism (SNP) with liver gene expression.Methods Western Blot was used to detect CAPON protein expression in human tissues. Steatotic hepatocytes levels were measured by histopathology study. Human Genome4302.0microarrays were performed to identify gene expression levels in liver samples from subjects with AA allele carriers (n=5) and C allele carriers (n=5). Quantitative real time PCR was applied to quantify mRNA expression levels. Microarray data were analyzed using SAM and function analysis.Results CAPON protein was highly expressed in human liver. The proposition of subjects with fatty liver is higher in C allele carriers (69.2%) than that in AA allele carriers (40%)(P<0.05). With a threshold of P<0.05and fold change>1.4or <0.7,164dif-genes were identified. Gene ontology (GO) analysis showed the main component of the GO annotation taken into consideration was metabolic function. Quantitative real time PCR showed that GSTM1, HBA1and HBB mRNA expressions were significantly down-regulated in liver with C allele carriers, whereas PC and PDK4, the two enzymes involving gluconeogenesis, were significantly up-regulated in C allele carriers.Conclusion CAPON rs12742393SNP was associated with decreased expression of genes involving anti-oxidative stress and increased expression of genes in gluconeogenesis. Our data indicated that CAPON might play a role in regulation of liver function in the development of NAFLD. Part2Liver genomics changes in early stage hepatic steatosisObjective Nonalcoholic fatty liver disease (NAFLD) has emerged as a growing public health problem and is associated with obesity and type2diabetes. The pathogenesis of the disorder is not fully clarified. The aim of present study was to evaluate the gene expression in the early stage of NAFLD.Methods The liver tissues were obtained from patients of benign focal hepatic lesions undergoing liver surgery at the Department of Liver Surgery. Affymatrix GeneChip Human Genome U133Plus2.0Array was used to investigate the gene expression in human liver of subjects with early stage liver steatosis (15-25%of hepatocytes with fat) and controls without fatty liver (<5%of hepatocytes with fat). Real-time PCR was used for the confirmation.Results With a threshold of P<0.05and fold change (fatty liver group/control group)>1.4or<0.7, we identified162probes which represent128dif-genes. Among them,53genes were involved in metabolic process by Gene ontology analysis. Pathway analysis showed that genes involved in triglyceride synthesis (AGPAT2, GK) and fatty acid transport (CD36) were unregulated, while genes involved in de novo fatty acid synthesis (ACACA, FASN, ELOVL6) were down-regulated in subjects with fatty liver. Two regulating factors (FGF21and Clorf85) were also up-regulated in subjects with fatty liver. No changes could be found in genes responsible for β-oxidation and VLDL secretion.Conclusion Increased fatty acid transport and triglyceride synthesis might be the earlier step in the development of NAFLD.