Phytic acid-based nanomedicine against mTOR represses lipogenesis and immune response for metabolic dysfunction-associated steatohepatitis therapy.

Abstract

Metabolic dysfunction-associated steatohepatitis (MASH) is one of the most common chronic liver diseases and is mainly caused by metabolic disorders and systemic inflammatory responses. Recent studies have indicated that the activation of the mammalian (or mechanistic) target of rapamycin (mTOR) signaling participates in MASH progression by facilitating lipogenesis and regulating the immune microenvironment. Although several molecular medicines have been demonstrated to inhibit the phosphorylation or activation of mTOR, their poor specificity and side effects limit their clinical application in MASH treatment. Phytic acid (PA), as an endogenous and natural antioxidant in the liver, presents significant anti-inflammatory and lipid metabolism-inhibiting functions to alleviate MASH. In this study, considering the unique phosphate-rich structure of PA, we developed a cerium-PA (CePA) nanocomplex by combining PA with cerium ions possessing phosphodiesterase activity. CePA intervened in the S2448 phosphorylation of mTOR through the occupation effect of phosphate groups, thereby inhibiting the inflammatory response and mTOR-sterol regulatory element-binding protein 1 (SREBP1) regulation axis. The in vivo experiments suggested that CePA alleviated MASH progression and fat accumulation in high-fat diet-fed mice. Mechanistic studies validated that CePA exerts a liver-targeted mTOR repressive function, making it a promising candidate for MASH and other mTOR-related disease treatments.