Using proteomics to discover novel biomarkers for fatty liver development and response to CB1R antagonist treatment in an obese mouse model

Abstract

Over activity of cannabinoid receptor type 1 (CB1R) plays a key role in increasing the incidence of obesity-induced non-alcoholic fatty liver disease. Tissue proteome analysis has been applied to investigate the bioinformatics regarding the mode of action and therapeutic mechanism. The aim of this study was to explore the potential pathways altered with CB1R in obesity-induced fatty liver. Male C57BL/6 mice were fed either a standard chow diet (STD) or a high-fat diet (HFD) with or without 1-week treatment of CB1R inverse agonist AM251 at 5 mg/kg. Then, liver tissues were harvested for 2DE analysis and protein profiles were identified by using MALDI-MS. Results showed that eight of significantly altered protein spots at the level of changes > twofold were overlapped among the three groups, naming major urinary protein 1, ATP synthase subunit β, glucosamine-fructose-6-phosphate aminotransferase 1, zine finger protein 2, s-adenosylmethionine synthase isoform type-1, isocitrate dehydrogenase subunit α, epoxide hydrolase 2 and 60S acidic ribosomal protein P0. These identified proteins were involved in glucose/lipid metabolic process, xenobiotic metabolic system, and ATP synthesized process in mitochondria. Based on the findings, we speculated that CB1R blockade might exert its anti-metabolic disorder effect via improvement of mitochondrial function in hepatic steatosis in HFD condition.

Cyclophilin D deficiency attenuates mitochondrial perturbation and ameliorates hepatic steatosis

“…We noted that the change of CypD was earlier than TG accumulation in the liver. Chen et al detected mitochondrial respiratory dysfunction and TG accumulation in mouse liver at 12 weeks of HFD feeding . To check the exact relationship between CypD and TG contents, we fed mice the HFD for different time periods and confirmed that CypD expression was up‐regulated at the end of the fourth week of HFD feeding and gradually enhanced as time passed.…”

“…Chen et al detected mitochondrial respiratory dysfunction and TG accumulation in mouse liver at 12 weeks of HFD feeding. (31) To check the exact relationship between CypD and TG contents, we fed mice the HFD for different time periods and confirmed that CypD expression was up-regulated at the end of the fourth week of HFD feeding and gradually enhanced as time passed. However, we failed to detect increased TG levels in the liver until the end of 8 weeks, which suggested that HFD-induced hepatic steatosis might be related to CypD expression.…”

Cannabinoid receptor type 1 antagonist inhibits progression of obesity‐associated nonalcoholic steatohepatitis in a mouse model by remodulating immune system disturbances

“…Liver sections were prepared by embedding them in optimal cutting temperature (OCT) solution on dry ice; they were then cut and stained with Oil‐Red O reagent (Sigma‐Aldrich) to visualize fat droplet accumulation. Lipid extraction from the liver tissues was performed according to our previous protocol 21 . Briefly, the liver tissues were homogenized in a 10× volume (w/v) of 2:1 chloroform/methanol, followed by centrifugation at 5000 g at room temperature for 15 minutes.…”

“…Lipid extraction from the liver tissues was performed according to our previous protocol. 21 Briefly, the liver tissues were homogenized in a 10× volume (w/v) of 2:1 chloroform/methanol, followed by centrifugation at 5000g at room temperature for 15 minutes. The lipid layer was washed with a 0.2× volume of 0.9% saline and centrifuged again at 5000g for 5 minutes.…”

Transcriptomic mapping of key reproductive and metabolic tissues and oocytes in mouse models of polycystic ovary syndrome

“…S2). The functional enrichment analyses in these models showed that Mup1 is involved in glucose homeostasis an indicator of insulin sensitivity (Chen et al, 2015). In the 17NF model, functional enrichment of DEGs in the glucose homeostasis displayed upregulation of Insr, Irs1, Ppara, Acacb, Dgal2, and Rorc (Supplementary Fig.…”