Liver targeting by microRNA-26b loaded lipid nanoparticles. Image credit: Peters et al. (Created in BioRender, https://BioRender.com/fpdp6hk; CC BY 4.0)
Fatty liver disease is a condition characterized by the abnormal accumulation of fat in the liver. In certain cases, the fatty build-up can lead to inflammation and, in time, scarring. This advanced stage is known as MASH (short for metabolic dysfunction-associated steatohepatitis), and it can increase the risk of liver failure, cancer, and other complications. Yet the underlying mechanisms that initiate inflammation and thereby drive the disease are still poorly understood. Identifying the molecular factors contributing to this transition could aid in discovering new treatment targets.
To explore this question, Peters et al. focus on microRNA-26b, a small molecule involved in many heart and metabolic diseases that helps regulate gene expression. They aimed to clarify the role of microRNA-26b in MASH using mice genetically manipulated to lack this regulatory molecule. The experiments revealed that the animals had larger amounts of fat in their livers, with the organs also showing clear signs of scarring and increased inflammation – including high levels of inflammatory signalling molecules and the presence of immune cells known as macrophages.
Peters et al. then treated the animals with specially designed compounds that can act as microRNA-26b. The molecules were safely delivered to the liver within tiny fat-based spheres known as lipid nanoparticles. Following such treatment, the mice showed decreased levels of liver fat and inflammation. The anti-inflammatory effect of the microRNA-26b ‘mimics’ was also confirmed in human liver samples.
Together, these results show that microRNA-26b plays a protective role in the development of MASH. Future research should focus on confirming whether these molecules could represent a viable therapeutic treatment, in particular when delivered within lipid-based nanoparticles.
