Abstract
Background and Objectives: As a key mechanism of metabolic dysfunction-associated steatotic liver disease (MASLD) pathogenesis, inflammation triggered by chronic liver injury and immune cells with macrophages enables MASLD to progress to an advanced stage with irreversible processes such as fibrosis, cell necrosis, and cancer in the liver. The complexity of MASLD, including crosstalk between multiple organs and the liver, makes developing a new drug for MASLD challenging, especially in single-drug therapy. It was reported that upregulation of Notch1 is closely associated with the function of pro-inflammatory macrophages. To leverage this signaling pathway in treating MASLD, we developed a combination therapy. Materials and Methods: We chose Notch1 siRNA (siNotch1) to block the Notch pathway so that phenotypic regulation and functional recovery can be achieved in macrophages, combining with small molecule drug AMD3100. AMD3100 can cut off the migration of inflammatory cells to the liver to impede the development of inflammation and inhibit the CXCL12/CXCR4 biological axis in liver fibrosis to protect against the activation of HSCs. Then, we investigated the efficacy of the combination therapy on resolving inflammation and MASLD. Results: We demonstrated that in liver cells, siNotch1 combined with AMD3100 not only directly modulated macrophages by downregulating multiple pathways downstream of Notch, exerting anti-inflammatory, anti-migration, and switch of macrophage phenotype, but also modulated macrophage phenotypes through inhibiting NET release. The restored macrophages further regulate HSC and neutrophils. In in vivo pharmacodynamic studies, combination therapy exhibits a superior therapeutical effect over monotherapy in MASLD models. Conclusions: These results constitute an siRNA therapeutical approach combined with a small molecule drug against inflammation and liver injury in MASLD, offering a promising therapeutic intervention for MASLD.