Expression of P-glycoprotein, encoded by MDR 1 gene, a metabolically active efflux pump in murine mast cells

Area of Science:

• Immunology
• Cell Biology
• Pharmacology

Background:

• Mast cells are key immune cells involved in allergic responses and inflammation.
• P-glycoprotein (P-gp) is a well-known efflux transporter implicated in multidrug resistance.

Purpose of the Study:

• To investigate the expression and function of P-glycoprotein (P-gp) in a murine mast cell line (MC/9).
• To determine if P-gp in mast cells is functionally active and capable of transporting substrates.

Main Methods:

• P-gp expression was assessed at both protein (flow cytometry, Western blot) and mRNA (RT-PCR) levels.
• Rhodamine 123 (Rh123) accumulation and efflux assays were performed in the presence and absence of cyclosporin A (CSA) and its analog (CSA-1).

Main Results:

• P-glycoprotein (P-gp) was detected in mast cells at both protein and mRNA levels.
• Cyclosporin A (CSA) and CSA-1 significantly increased intracellular accumulation of Rh123 and inhibited its efflux, indicating P-gp activity.
• These results confirm the presence of a functionally active P-gp in mast cells.

Conclusions:

• Mast cells express functionally active P-glycoprotein (P-gp).
• The study suggests a potential physiological role for P-gp in the secretion of mediators and cytokines from mast cells.
• This highlights P-gp as a potential target for modulating mast cell function.