GENERATION OF HEPATIC STELLATE CELLS BY DIRECTED DIFFERENTIATION OF HUMAN PLURIPOTENT STEM CELLS

Hepatic stellate cells (HSC) are the main stromal cell component of the liver. In healthy liver, quiescent HSC participate in the homeostasis of extracellular matrix (ECM) and store vitamin A. Liver injury causes HSC activation, where they participate in the wound-healing response, by producing ECM components as well as cytokines involved in liver regeneration and inflammation. Moreover, HSC are the main cell type responsible for fibrosis progression. The lack of homogeneous cultures and renewable sources of human HSC has limited the studies of the role of HSC in liver injury, repair anf fibrosis. Here we report a procedure to direct the differentiation of human pluripotent stem cells (PSC) to HSC. The HSC–like population (iPS-HSC) was enriched in PDGFRβ positive cells that expressed key HSC markers. Whole genome transcriptomic analysis revealed that iPS-HSC displayed features intermediate to quiescent and activated HSC. Functional analysis demonstrated that iPS-HSC accumulated retinyl esters into lipid droplets and responded to injury mediators. Moreover, when cultured with HepaRG hepatocytes as aggregates, iPS-HSC support long-term hepatocyte metabolic function and respond to hepatocyte toxicity by activating and promoting organoid fibrogenesis. The genome wide transcriptome of 3 freshly isolated iPS-HSC cells (iHSC), 3 iPS-HSC cells at passage 1 iHSC_p1), 3 iPSC samples harvested from the differentiation plate on day 0, (IPSC) and finally, 3 parental BJ1 fibroblast (hfibro) samples were assessed using Affymetrix HG-U219 genechips (Affymetrix)