Up-regulation and cytoprotective role of epithelial multidrug resistance-associated protein 1 in inflammatory bowel disease.

MRP1 (multidrug resistance-associated protein 1) is well known for its role in providing multidrug resistance to cancer cells. In addition, MRP1 has been associated with both pro- and anti-inflammatory functions in nonmalignant cells. The pro-inflammatory function is evident from the fact that MRP1 is a high affinity transporter for cysteinyl-leukotriene C4 (LTC4), a lipid mediator of inflammation.

Decreased P-glycoprotein (P-gp/MDR1) expression in inflamed human intestinal epithelium is independent of PXR protein levels.

Background: Altered P-glycoprotein expression (P-gp/MDR1) and/or function may contribute to the pathogenesis of gastrointestinal inflammatory disorders. Low intestinal mRNA levels of the pregnane X receptor (PXR) have been linked to low MDR1 mRNA levels in patients with ulcerative colitis (UC). Here we compared intestinal MDR1 mRNA and protein expression in uninflamed and inflamed intestinal epithelium (IE) of patients with gastrointestinal inflammatory disorders to healthy controls.

High expression of MDR1, MRP1, and MRP3 in the hepatic progenitor cell compartment and hepatocytes in severe human liver disease.

An increase in bile ductular structures is observed in diverse human liver diseases. These structures harbour the progenitor cell compartment of the liver. Since ATP-binding cassette (ABC) transporters may have a cytoprotective role in liver disease, an immunohistochemical study was performed on human liver specimens from patients with primary biliary cirrhosis (PBC), chronic hepatitis C virus (HCV) infection, submassive cell necrosis, and normal liver.