[Alterations in expression and function of ABC transporters and ERM proteins in inflammation]

Area of Science:

• Pharmacology
• Biochemistry
• Cell Biology

Background:

• Inflammation alters the production of proteins involved in drug absorption, distribution, metabolism, and excretion (ADME).
• Limited information exists on how inflammation affects ATP-binding cassette (ABC) transporter expression and activity.

Purpose of the Study:

• To investigate the effects of acute and chronic inflammation on ABC transporter expression in major rat tissues.
• To explore the role of ezrin/radixin/moesin (ERM) proteins in the altered membrane localization of ABC transporters during inflammation.

Main Methods:

• Adjuvant-induced arthritis (AA) model in rats to simulate inflammation.
• Quantification of mRNA levels for mdr1a and mdr1b (encoding P-glycoprotein).
• Measurement of hepatic protein levels of P-glycoprotein (P-gp), Mrp2, and Bcrp in membrane and homogenate fractions.

Main Results:

• Significant decrease in mdr1a and mdr1b mRNA in the liver of AA rats on day 21.
• Reduced hepatic membrane protein levels of P-gp, Mrp2, and Bcrp in AA rats at both 7 and 21 days.
• Observed decreased membrane localization of ABC transporters without changes in total expression levels, suggesting ERM protein involvement.

Conclusions:

• Acute and chronic inflammation significantly downregulate hepatic ABC transporter expression and membrane localization in rats.
• ERM proteins may play a crucial role in mediating the reduced membrane presence of ABC transporters during inflammation.
• Findings highlight potential implications for drug efficacy and toxicity in inflammatory conditions.