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Effect of miR-34a in regulating steatosis by targeting PPARα expression in nonalcoholic fatty liver disease.

Ding J, Li M, Wan X, Jin X, Chen S, Yu C, Li Y - Sci Rep (2015)

Bottom Line: The upregulation of miR-34a resulted in the downregulation of hepatic PPARα and SIRT1 that are the direct targets of miR-34a.Activation of the central metabolic sensor AMPK was also increased.The miR-34a inhibitor suppressed lipid accumulation and improved the degree of steatosis.

View Article: PubMed Central - PubMed

Affiliation: Department of Infectious Diseases, Hangzhou First People's Hospital, No. 261 Huansha Road, Hangzhou 310006, Zhejiang Province, China.

ABSTRACT
MicroRNA-34a (miR-34a) is thought to be involved in nonalcoholic fatty liver disease (NAFLD). However, the association between altered expression of miR-34a and the pathophysiological features of NAFLD remains unclear. Here, we investigated the mechanisms by which miR-34a influences NAFLD through the PPARα-related pathway. Real-time quantitative PCR, western blotting and other assays kit were used to investigate the expression and function of miR-34a in an NAFLD model. Cultured cells transfected with miR-34a inhibitor and C57BL/6 mice injected with the miR-34a inhibitor through vein tail were conducted for the effects of miR-34a on its target. MiR-34a levels were significantly upregulated in steatosis-induced hepatocytes and in liver tissues of high-fat diet-fed mice. The upregulation of miR-34a resulted in the downregulation of hepatic PPARα and SIRT1 that are the direct targets of miR-34a. Silencing miR-34a led to an initially increased expression of PPARα, SIRT1 and PPARα's downstream genes. Activation of the central metabolic sensor AMPK was also increased. The miR-34a inhibitor suppressed lipid accumulation and improved the degree of steatosis. Taken together, our data indicated that decreased expression of miR-34a potentially contributes to altered lipid metabolism in NAFLD. Downregulation of miR-34a may be a therapeutic strategy against NAFLD by regulating its target PPARα and SIRT1.

No MeSH data available.


Related in: MedlinePlus

Activated AMPK pathway in L02 cells and mouse liver tissues.Western blotting for phospho-AMPKα1 catalytic subunit in liver extracts from mice treated with miR-34 inhibitor or NC in vitro for 24 hours or in vivo for 4 weeks. The miR-34a inhibitor activated the AMPK pathway. The results were standardized to the control group and presented as the mean ± standard deviation of three independent experiments. The blots were cropped and the gels were run under the same experimental conditions. *P < 0.05.
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f5: Activated AMPK pathway in L02 cells and mouse liver tissues.Western blotting for phospho-AMPKα1 catalytic subunit in liver extracts from mice treated with miR-34 inhibitor or NC in vitro for 24 hours or in vivo for 4 weeks. The miR-34a inhibitor activated the AMPK pathway. The results were standardized to the control group and presented as the mean ± standard deviation of three independent experiments. The blots were cropped and the gels were run under the same experimental conditions. *P < 0.05.

Mentions: To elucidate the mechanism by which the miR-34a inhibitor reduced TG accumulation in L02 cells, we assessed the effect of miR-34a on lipid metabolism pathways. Increased AMPK phosphorylation is associated with enhanced lipid metabolism, especially increased fatty acid β-oxidation2223. We found that AMPK phosphorylation was significantly reduced, with the pAMPK/AMPKα1 ratio reduced by about 27% in FFA induced cells compared with control cells (Fig. 5A). The miR-34a inhibitor increased the pAMPK/AMPKα1 ratio compared with the NC. These data suggested a role for AMPK in miR-34a’s effects on fat accumulation in vitro.


Effect of miR-34a in regulating steatosis by targeting PPARα expression in nonalcoholic fatty liver disease.

Ding J, Li M, Wan X, Jin X, Chen S, Yu C, Li Y - Sci Rep (2015)

Activated AMPK pathway in L02 cells and mouse liver tissues.Western blotting for phospho-AMPKα1 catalytic subunit in liver extracts from mice treated with miR-34 inhibitor or NC in vitro for 24 hours or in vivo for 4 weeks. The miR-34a inhibitor activated the AMPK pathway. The results were standardized to the control group and presented as the mean ± standard deviation of three independent experiments. The blots were cropped and the gels were run under the same experimental conditions. *P < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4557122&req=5

f5: Activated AMPK pathway in L02 cells and mouse liver tissues.Western blotting for phospho-AMPKα1 catalytic subunit in liver extracts from mice treated with miR-34 inhibitor or NC in vitro for 24 hours or in vivo for 4 weeks. The miR-34a inhibitor activated the AMPK pathway. The results were standardized to the control group and presented as the mean ± standard deviation of three independent experiments. The blots were cropped and the gels were run under the same experimental conditions. *P < 0.05.
Mentions: To elucidate the mechanism by which the miR-34a inhibitor reduced TG accumulation in L02 cells, we assessed the effect of miR-34a on lipid metabolism pathways. Increased AMPK phosphorylation is associated with enhanced lipid metabolism, especially increased fatty acid β-oxidation2223. We found that AMPK phosphorylation was significantly reduced, with the pAMPK/AMPKα1 ratio reduced by about 27% in FFA induced cells compared with control cells (Fig. 5A). The miR-34a inhibitor increased the pAMPK/AMPKα1 ratio compared with the NC. These data suggested a role for AMPK in miR-34a’s effects on fat accumulation in vitro.

Bottom Line: The upregulation of miR-34a resulted in the downregulation of hepatic PPARα and SIRT1 that are the direct targets of miR-34a.Activation of the central metabolic sensor AMPK was also increased.The miR-34a inhibitor suppressed lipid accumulation and improved the degree of steatosis.

View Article: PubMed Central - PubMed

Affiliation: Department of Infectious Diseases, Hangzhou First People's Hospital, No. 261 Huansha Road, Hangzhou 310006, Zhejiang Province, China.

ABSTRACT
MicroRNA-34a (miR-34a) is thought to be involved in nonalcoholic fatty liver disease (NAFLD). However, the association between altered expression of miR-34a and the pathophysiological features of NAFLD remains unclear. Here, we investigated the mechanisms by which miR-34a influences NAFLD through the PPARα-related pathway. Real-time quantitative PCR, western blotting and other assays kit were used to investigate the expression and function of miR-34a in an NAFLD model. Cultured cells transfected with miR-34a inhibitor and C57BL/6 mice injected with the miR-34a inhibitor through vein tail were conducted for the effects of miR-34a on its target. MiR-34a levels were significantly upregulated in steatosis-induced hepatocytes and in liver tissues of high-fat diet-fed mice. The upregulation of miR-34a resulted in the downregulation of hepatic PPARα and SIRT1 that are the direct targets of miR-34a. Silencing miR-34a led to an initially increased expression of PPARα, SIRT1 and PPARα's downstream genes. Activation of the central metabolic sensor AMPK was also increased. The miR-34a inhibitor suppressed lipid accumulation and improved the degree of steatosis. Taken together, our data indicated that decreased expression of miR-34a potentially contributes to altered lipid metabolism in NAFLD. Downregulation of miR-34a may be a therapeutic strategy against NAFLD by regulating its target PPARα and SIRT1.

No MeSH data available.


Related in: MedlinePlus