Previous research has demonstrated that microRNAs (miRNAs) are endogenously encoded RNAs that regulate the stability or translation of mRNA molecules. Now, new research suggests that these RNAs have diverse roles in normal physiology and disease.
In this issue, two groups investigated the role of the predominant liver miRNA, miR-122. Ann-Ping Tsou and colleagues from National Yang-Ming University in Taiwan, and a team led by Kalpana Ghoshal, from Ohio State University generated mouse models of MiR-122 loss of function, and determined that the molecule was critically involved in modulating fat and cholesterol metabolism, and may also have a tumor suppressive function in hepatocytes. In the accompanying commentary, Jessica Wen and Joshua Friedman of the University of Pennsylvania discuss these findings, and suggest the possibility that miR-122 might be a promising therapeutic target in hepatocellular carcinoma.