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Updated: Jun 5, 2025
Exploring the Regulation of Lipid Droplet Catabolism through Lipophagy
Published on: January 31, 2025
Free fatty acid-induced DDX3 inhibits autophagy via miR-141 upregulation in diet-induced MASLD mice model system
Md Musa Hossain1, Amit K Mishra2, Ajay K Yadav3
1Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, India.
Introduction And Objectives:
Metabolic dysfunction-associated steatotic liver disease (MASLD) is one of the primary causes of chronic liver disease and may lead to liver cirrhosis and hepatocellular carcinoma. Recent reports suggested that DEAD-box RNA helicase (DDX3) acts as a sensor of free fat accumulation and may modulate the pathogenesis via miRNAs. Hence, we hypothesized that DDX3 might modulate MASLD progression via miRNA-141-mediated inhibition of Sirt-1 and autophagy.
Materials And Methods:
RNA and total protein were isolated from free fatty acid-treated HepG2 cells or CDAA-fed C57BL/6 mice (6 mice per group) for 6, 18, 32, or 54 weeks. The cells were transfected with DDX3 or miR-141 or siRNA to DDX3, and Western blots for autophagy markers were performed.
Results:
The FFAs induced the DDX3 and miRNA-141 expression, while downregulating Sirt-1, beclin-1, Atg7, and LC3-II. Overexpression of DDX3 resulted in increased miRNA-141. Overexpression of DDX3 or miRNA-141 downregulated Sirt-1 expression and autophagy marker proteins, while these effects were reversed with siRNA to DDX3. The expression of both DDX3 and miRNA-141 was significantly increased, while autophagy markers were downregulated in CDAA-fed mice.
Conclusions:
These results confirmed that FFA-induced DDX3 induced the expression of miRNA-141, which in turn targeted Sirt-1 and decreased autophagy.
Insights
Free fatty acids induce DEAD-box RNA helicase (DDX3) and miRNA-141, which inhibits Sirt-1 and autophagy, promoting metabolic dysfunction-associated steatotic liver disease (MASLD) progression.
Area of Science:
- Hepatology
- Molecular Biology
- Biochemistry
Background:
- Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major cause of chronic liver disease, potentially leading to cirrhosis and cancer.
- DEAD-box RNA helicase (DDX3) is implicated as a free fat sensor that may influence disease pathways through microRNAs (miRNAs).
Purpose of the Study:
- To investigate the role of DDX3 in MASLD pathogenesis.
- To determine if DDX3 modulates MASLD progression via miRNA-141, targeting Sirt-1 and autophagy.
Main Methods:
- HepG2 cells and C57BL/6 mice were treated with free fatty acids (FFAs) or a choline-deficient amino acid-defined (CDAA) diet.
- Gene and protein expression of DDX3, miRNA-141, Sirt-1, and autophagy markers were analyzed using Western blots and RNA isolation.
- Cell transfection with DDX3, miRNA-141, or siRNA to DDX3 was performed.
Main Results:
- FFA treatment and CDAA diet increased DDX3 and miRNA-141 expression while decreasing Sirt-1 and autophagy markers (beclin-1, Atg7, LC3-II).
- Overexpression of DDX3 elevated miRNA-141 levels, leading to reduced Sirt-1 and autophagy.
- Silencing DDX3 reversed these effects, indicating a causal link.
Conclusions:
- FFA-induced DDX3 upregulates miRNA-141 expression.
- miRNA-141 directly targets Sirt-1, leading to decreased autophagy.
- This pathway contributes to the progression of MASLD.
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