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 expression of long noncoding RNAs 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.