Modulation of MRP1-like efflux activity in human erythrocytes caused by membrane perturbing agents

Area of Science:

• Biochemistry
• Cell Biology
• Pharmacology

Background:

• The efflux of molecules from cells is crucial for drug transport and detoxification.
• Multi-drug resistance protein 1 (MRP1, ABCC1) is an important transporter involved in cellular efflux.
• Understanding how membrane-perturbing agents affect transporter activity is vital for drug development.

Purpose of the Study:

• To investigate the impact of various amphiphiles on the efflux of 2', 7'-bis-(carboxypropyl)-5(6)-carboxyfluorescein (BCPCF) from human erythrocytes.
• To determine the structural features of amphiphiles responsible for modulating BCPCF efflux.
• To elucidate the role of MRP1 in amphiphile-mediated inhibition of BCPCF efflux.

Main Methods:

• Studied the efflux of the fluorescent probe BCPCF from human erythrocytes at 37°C for 60 minutes.
• Utilized a range of anionic, zwitter-ionic, non-ionic, and cationic amphiphiles as membrane-perturbing agents.
• Determined the IC50 values for inhibitory amphiphiles and assessed the effects of other agents like MbetaCD and diamide.

Main Results:

• Anionic amphiphiles significantly inhibited BCPCF efflux, with IC50 values ≤ 40 μM.
• C12-homologues were the most effective aliphatic inhibitors.
• Zwitter-ionic, non-ionic, and cationic amphiphiles showed minimal or no inhibitory effects, while some increased efflux.
• Hexanol, ethanol, MbetaCD, and diamide did not influence BCPCF efflux.
• Amphiphile-mediated inhibition was dependent on negative charge and modulated by alkyl chain length.

Conclusions:

• Amphiphiles modulate MRP1 activity, affecting BCPCF efflux from human erythrocytes.
• The inhibitory effect of amphiphiles on MRP1 is dependent on their negative charge and alkyl chain length.
• MRP1-mediated BCPCF efflux is relatively resistant to non-specific modifications of the plasma membrane.