NORAD exacerbates metabolic dysfunction-associated steatotic liver disease development via the miR-511-3p/Rock2 axis and inhibits ubiquitin-mediated degradation of ROCK2

Background & aims

Abnormal regulation of lncRNA is strongly linked to metabolic dysfunction-associated steatotic liver disease (MASLD). However, the precise molecular mechanisms remain unclear. This study explores the roles of noncoding RNA activated by DNA damage (NORAD)/miR-511-3p/Rho-associated protein kinase 2 (Rock2) axis and the NORAD/ROCK2 interaction in the development of MASLD.

Methods

In vitro and in vivo models of MASLD were created using high-fat diet-fed mice and free fatty acid (FFA)-treated hepatocytes. To examine the relationships between NORAD, miR-511-3p, and ROCK2, we employed bioinformatics, luciferase assays, RNA immunoprecipitation, and biotinylated NORAD pull-down assays. MASLD progression was assessed based on food intake, energy expenditure, insulin resistance, hepatic steatosis, inflammation, white fat growth, and liver fibrosis.

Results

NORAD and ROCK2 were upregulated, while miR-511-3p was downregulated in MASLD liver tissues and FFA-treated hepatocytes. Mechanistically, NORAD competitively interacted with miR-511-3p to modulate Rock2 mRNA expression, and directly stabilized ROCK2 protein by abrogating its ubiquitination degradation. Functionally, liver-specific knockdown of NORAD or overexpression of miR-511-3p significantly slowed MASLD progression. Overexpression of NORAD or ROCK2 partially reversed miR-511-3p-induced inhibition of MASLD. Additionally, ROCK2 knockdown attenuated NORAD-induced worsening of MASLD. Moreover, overexpressing NORAD or ROCK2 or interfering miR-511-3p influenced resmetirom treatment to suppress MASLD development. Finally, metabolic changes in liver driven by the NORAD/miR-511-3p/Rock2 axis and NORAD/ROCK2 interaction also influenced white adipose growth, pancreatic β-cell dedifferentiation, and liver fibrosis.

Conclusions

The NORAD/miR-511-3p/Rock2 axis and the NORAD/ROCK2 interaction play critical roles in MASLD progression, identifying potential therapeutic targets for its treatment.