The prevalence of nonalcoholic fatty liver disease (NAFLD) has increased with the incidence of obesity; however, the underlying mechanisms are unknown. In this study, high-resolution metabolomics (HRM) along with transcriptomics were applied on animal models to draw a mechanistic insight of NAFLD. Wild type (WT) and catalase knockout (CKO) mice were fed with normal fat diet (NFD) or high fat diet (HFD) to identify the changes in metabolic and transcriptomic profiles caused by catalase gene deletion in correspondence with HFD. Integrated omics analysis revealed that cholic acid and 3β, 7α-dihydroxy-5-cholestenoate along with cyp7b1 gene involved in primary bile acid biosynthesis were strongly affected by HFD. The analysis also showed that CKO significantly changed all-trans-5,6-epoxy-retinoic acid or all-trans-4-hydroxy-retinoic acid and all-trans-4-oxo-retinoic acid along with cyp3a41b gene in retinol metabolism, and α/γ-linolenic acid, eicosapentaenoic acid and thromboxane A2 along with ptgs1 and tbxas1 genes in linolenic acid metabolism. Our results suggest that dysregulated primary bile acid biosynthesis may contribute to liver steatohepatitis, while up-regulated retinol metabolism and linolenic acid metabolism may have contributed to oxidative stress and inflammatory phenomena in our NAFLD model created using CKO mice fed with HFD.

BACKGROUND: Peroxisome proliferators-activated receptor gamma (PPARgamma) is a member of the nuclear hormone receptor superfamily of ligand-activated transcription factors and known to play a role in regulating the expression of numerous genes involved in lipid metabolism, metabolic syndrome, inflammation, and atherosclerosis. The PPARgamma2 Pro12Ala polymorphism has recently been shown to be associated with diabetic nephropathy. In this study, we evaluated the relationship between PPARgamma2 Pro12Ala polymorphism and type 2 diabetic nephropathy whose duration of diabetes was over 10 years. METHODS: We conducted a case-control study, which enrolled 367 patients with type 2 diabetes. Genotyping of PPARgamma2 Pro12Ala polymorphism was performed using polymerase chain reaction followed by digestion with Hae III restriction enzyme. RESULTS: The genotype or allele frequencies of PPARgamma2 Pro12Ala polymorphism were not significantly different in diabetic patients with or without diabetic nephropathy. The genotype frequencies in terms of diabetic retinopathy and macrovascular complications such as coronary artery disease or stroke were not different either. Interestingly, nephropathy patients with Ala/Pro genotype showed lower C-peptide levels than those of Pro/Pro genotype. CONCLUSION: Our results suggest that PPARgamma2 Pro12Ala polymorphism is not associated with diabetic nephropathy in type 2 diabetic patients.
Atherosclerosis ; C-Peptide ; Case-Control Studies ; Coronary Artery Disease ; Diabetic Nephropathies ; Diabetic Retinopathy ; Digestion ; Gene Frequency ; Genotype ; Humans ; Inflammation ; Lipid Metabolism ; Peroxisomes ; Polymerase Chain Reaction ; PPAR gamma ; Stroke ; Transcription Factors