Characterization of Pro-Fibrotic Signaling Pathways using Human Hepatic Organoids

Abstract

AbstractDue to the limitations of availablein vitrosystems and animal models, we lack a detailed understanding of the pathogenetic mechanisms and have minimal treatment options for liver fibrosis. To overcome this barrier, we engineered a live cell imaging system that identifies collagen producing cells in a human multi-lineage hepatic organoid. This system was adapted for use as a microwell-based platform (i.e., microHOs) where exposure to PDGF or TGFβ1 induced the formation of thick collagen fibers. Transcriptomic analysis revealed that TGFβ1 exposure converted mesenchymal cells into myofibroblast-like cells, which contribute to the development of liver fibrosis. When pro-fibrotic intracellular signaling pathways were examined using pharmacological probes, the anti-fibrotic effect of receptor-specific tyrosine kinase inhibitors was limited to the fibrosis induced by the corresponding growth factor, which indicates that their anti-fibrotic efficacy would be limited to fibrotic diseases that were solely mediated by that growth factor. In contrast, GSK3β or p38 MAPK inhibitors could prevent TGFβ1- or PDGF- induced fibrosis in microHOs because they block intracellular signaling pathways that are commonly utilized by the TGFβ1 and PDGF receptors. Hence, these studies identified GSK3β and p38 MAPK inhibitors as potential new broad-spectrum therapies for liver fibrosis, and it is likely that other new therapies could subsequently be identified using this microHO system.