Targeting Intracellular Cholesterol Distribution: Mechanisms and Therapeutic Strategies for Metabolic dysfunction-associated steatotic liver disease (MASLD)

Abstract Hepatic steatosis, characterized by excessive hepatic lipid accumulation, is a major component of metabolic dysfunction-associated steatotic liver disease (MASLD), a growing global health concern. While Aster proteins (Aster-A, -B, and -C) have been implicated in intracellular cholesterol transport, their specific roles in MASLD progress remain incompletely understood. Our preliminary data suggested a potential link between Aster-C and hepatic lipid accumulation; however, mechanistic details require further investigation. Based on reviewer feedback and new preliminary data demonstrating minimal impact of Aster-C loss on intestinal lipid absorption, this revised application focuses specifically on the mechanistic underpinnings of Aster-C’s role in hepatic steatosis. We hypothesize that Aster-C modulates hepatic lipid accumulation through distinct mechanisms involving fatty acid uptake and de novo lipogenesis (DNL). To test this hypothesis, we propose three aims. Aim 1 will investigate the contribution of the Nrf1/Nfe2l1-CD36 pathway to hepatic lipid accumulation in the context of Aster-C deficiency and validate these findings using AAV8-mediated Aster-C overexpression in vivo. Aim 2 will examine the impact of Aster-C loss on DNL in hepatocytes, assessing key lipogenic enzymes and transcriptional regulators. These findings will be further validated in the Aster-C overexpression mouse model. Finally, Aim 3 will prioritize and refine candidate Aster-C modulating compounds (e.g., GSK-1215101A) through comprehensive pharmacokinetic, biodistribution, and toxicity studies. These studies will provide critical mechanistic insights into the role of Aster-C in hepatic lipid metabolism and pave the way for the development of targeted therapeutic strategies for MASLD.