Fig. 5.
Differentiation of mesothelial cells (MCs) in liver development and fibrosis. (A) During embryogenesis, mesoderm posterior 1 (MESP1)+ mesoderm gives rise to septum transversum mesenchyme (STM) and MCs. The MCs and underlying sub-MCs express Wilms tumor 1 (WT1). Cell-lineage tracing of WT1+ cells demonstrates their migration from the liver surface and differentiation into hepatic stellate cells (HSCs), fibroblasts (FBs) and smooth muscle cells (SMCs) around the blood vessels in mouse liver development. (B) Upon liver injury caused by CCl4 injection or bile duct ligation, MCs differentiate into myofibroblasts (MFs) or HSCs in adult mouse livers. Transforming growth factor β (TGF-β) provokes the mesothelial-mesenchymal transition.