Fig. 3.

Proposed inhibitory role of biliverdin reductase A (BVRA) in fibrogenesis. Hepatic stellate cells (HSCs) are activated by lipopolysaccharide (LPS) binding to toll-like receptor 4 (TLR4) or stimulation by transforming growth factor-β (TGF-β). Activated HSCs increase collagen production as well as several other factors to promote liver fibrogenesis. BVRA can attenuate fibrogenesis through antagonism of TLR4. α-SMA, α-smooth muscle actin; ROS, reactive oxygen species; TIMP-1, tissue inhibitor of metalloproteinases 1.