Mir-21: A Therapeutic Target That Delays Severe Liver Disease and Hepatocellular Carcinoma under High-Fat-diet Conditions

Abstract Liver disease is a major global health concern, claiming approximately 2 million lives worldwide annually, yet curative treatments remain elusive. In our study, we aimed to investigate the role of microRNA-21-5p (miR-21) in metabolic dysfunction-associated steatotic liver disease (previously NAFLD), metabolic-associated steatohepatitis (previously NASH), and hepatocellular carcinoma (HCC) within the context of a Western high-fat diet (HFD) and offering potential therapeutic insights. We found that reduced miR-21 levels correlated with liver disease progression in WT mice fed on HFD, while miR-21 knockout mice showed exacerbated metabolic dysfunction, including obesity, hepatomegaly, hyperglycemia, insulin resistance, steatosis, fibrosis, and HCC. Our study reveals that miR-21 plays a protective role in metabolic syndrome and in the progression of liver disease to cancer. miR-21 directly targets Transforming growth factor beta-induced (Tgfbi), a gene also known to be significantly upregulated and a potential oncogene in HCC. Further, our study showed that intervention with the administration of a miR-21 mimic in WT livers in HFD conditions effectively improves insulin sensitivity, steatosis, fibrosis, tumor burden, as well as Tgfbi expression. These findings indicate that miR-21 could serve as an effective strategy to delay or prevent liver disease in high-fat-diet environments. Citation Format: Urmila Jagtap, Anan Quan, Yuho Ono, Jonathan Lee, Kylie A. Shen, Sergei Manakov, Gyongyi Szabo, Imad Nasser, Frank J. Slack. miR-21: A therapeutic target that delays severe liver disease and hepatocellular carcinoma under high-fat-diet conditions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5689.