HMOX1 and cholestasis: The results showed that heme promoted HO-1 via the NRF2/BACH1 pathway; therefore, cholestasis was reduced in two ways: by stimulating hepatic Mrp3 expression to promote bile flow and increasing urinary bile-acid clearance by up-regulating renal Mrp2/Mrp4 expression or down-regulating renal Mrp3 expression (Muchova et al., 2015).