Peroxisome Proliferator-Activated Receptor Agonist IVA337 Alleviates Inflammation and Fibrosis in MASH by Restoring Lipid Homeostasis.

Metabolic dysfunction-associated steatohepatitis (MASH), an advanced stage of metabolic dysfunction-associated steatotic liver disease, is characterized by significant hepatic fibrosis and inflammation. The pan-peroxisome proliferator-activated receptor (pan-PPAR) agonist IVA337 (lanifibranor) has shown potential as an anti-MASH therapeutic, although its mechanisms of action remain incompletely understood. This study explores the effects and mechanisms of IVA337 using two distinct MASH models: two-dimensional (2D) primary human hepatic stellate cells (HSCs) stimulated with transforming growth factor β1 (TGF-β1), and three-dimensional (3D) liver spheroids comprising primary hepatocytes, HSCs, and non-parenchymal cells. In TGF-β1-stimulated HSCs, IVA337 effectively suppressed the expression of fibrosis-related genes, including PAI1, COL1A1, and ACAT2, as well as the inflammatory gene IL6. 3D mouse and human liver spheroid models of MASH, characterized by elevated fibrotic gene expression, were established. IVA337 treatment not only attenuated fibrotic gene expression but also restored lipid content in the MASH spheroids, as evidenced by BODIPY staining. Immunostaining further confirmed a reduction in α-smooth muscle actin and collagen 1 levels after IVA337 treatment. Bulk RNA sequencing and Gene Ontology analysis revealed several lipid metabolism-related genes as key effectors downstream of IVA337. In addition, IVA337 modulated multiple signaling pathways, including IL-17, tumor necrosis factor, NF-κB, phosphatidylinositol 3 kinase/protein kinase B, and mitogen-activated protein kinase. Collectively, these findings show that IVA337 effectively mitigates fibrosis development in both 2D and 3D MASH models by restoring lipid homeostasis and regulating crucial fibrotic and inflammatory pathways.