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Updated: Jun 2, 2025
Method for Measuring the Activity of Deubiquitinating Enzymes in Cell Lines and Tissue Samples
Published on: May 10, 2015
OTUB1 mediates PARP1 deubiquitination to alleviate NAFLD by regulating HMGB1
Shuhua Ai1, Juanli Pan2, Qi Liu3
1Department of Gastroenterology, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang City, 421001, Hunan province, China; Hunan Provincial Key Laboratory of Basic and Clinical Pharmacological Research of Gastrointestinal Cancer, the Second Affiliated Hospital, University of South China, Hengyang, 421001, Hunan, China.
Abstract:
Nonalcoholic fatty liver disease (NAFLD) is a common chronic disease characterized by hepatocyte steatosis, which excludes alcohol, drugs and other definite liver damage-related factors. It has been reported that OTUB1 serves a significant role in the regulation of glucose and lipid metabolism. The present study aimed to investigate the molecular mechanism underlying the effect of OTUB1 on regulating NAFLD. The NAFLD mouse model was induced via high-fat-diet, and glucose and insulin tolerance tests were then performed. In addition, the serum levels of total cholesterol (TC) and triglycerides (TG) were detected. The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were assessed using the corresponding biochemical assays. Hematoxylin and eosin, and periodic acid-Schiff staining was carried out to evaluate the liver pathology in mice. The expression levels of the NAFLD-related genes and inflammatory genes were determined by reverse transcription-quantitative PCR, Western blot analysis and immunofluorescence staining. Furthermore, the regulatory association between OTUB1 and poly (adenosine diphosphate-ribose) polymerase (PARP)-1 was assessed by co-immunoprecipitation assay. The results showed that OTUB1 was significantly upregulated in both in vitro and in vivo NAFLD models. Knockout of OTUB1 significantly improved affected glucose tolerance and insulin sensitivity, decreased TG and TC content, and decreased ALT, AST and ALP levels. In addition, the results show that OTUB1 can regulate the expression of PARP1 by inhibiting the ubiquitination of PARP1, while PARP1 knockout can inhibit liver inflammation by regulating HMGB1, thereby improving NAFLD. Targeting OTUB1 could be a potential therapeutic strategy for the NAFLD.
Insights
Targeting OTUB1, an enzyme upregulated in nonalcoholic fatty liver disease (NAFLD), shows promise. Reducing OTUB1 improves glucose/lipid metabolism and liver health, suggesting it as a potential therapeutic target for NAFLD.
Area of Science:
- Hepatology
- Molecular Biology
- Metabolic Diseases
Background:
- Nonalcoholic fatty liver disease (NAFLD) is a prevalent chronic condition marked by hepatocyte steatosis.
- OTUB1 is implicated in regulating glucose and lipid metabolism, suggesting a role in NAFLD pathogenesis.
Purpose of the Study:
- To elucidate the molecular mechanisms by which OTUB1 influences NAFLD.
- To investigate OTUB1's regulatory role in glucose and lipid metabolism within NAFLD models.
Main Methods:
- Established a high-fat-diet induced NAFLD mouse model.
- Performed glucose and insulin tolerance tests, measured serum lipid profiles (TC, TG) and liver enzymes (ALT, AST, ALP).
- Utilized molecular techniques including RT-qPCR, Western blot, immunofluorescence, and co-immunoprecipitation to assess gene expression, protein interactions, and pathological changes.
Main Results:
- OTUB1 expression was significantly elevated in NAFLD models.
- OTUB1 knockout ameliorated glucose intolerance, insulin resistance, reduced TG and TC levels, and decreased liver enzyme levels.
- OTUB1 regulates PARP1 expression by inhibiting its ubiquitination; PARP1 knockout mitigated liver inflammation via HMGB1, improving NAFLD.
Conclusions:
- OTUB1 plays a crucial role in the pathogenesis of NAFLD.
- Modulating OTUB1 activity, particularly by inhibiting its ubiquitination of PARP1, offers a potential therapeutic strategy for NAFLD.
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