SERPINE1 and fibrosis: Previous research has also suggested that CHOP deficiency significantly decreases the expression of the renal fibrosis markers collagen I, fibronectin, α-smooth muscle actin, and plasminogen activator inhibitor-1 in the kidneys of a mouse unilateral ureteral obstruction (UUO) model, and CHOP knockout also ameliorated tubular apoptosis and inflammatory cell infiltration in the UUO kidneys26.