Related Experiment Videos
Xenobiotic transport differences in mouse mesangial cell clones expressing mdr1 and mdr3
1Department of Internal Medicine, University of Texas Medical Branch, Galveston 77555, USA.
Abstract:
P-glycoprotein (PGP), which confers multidrug resistance to cancer cells, is expressed in mouse kidney proximal tubule and mesangium. We report on the expression of PGP and its xenobiotic transport function in mesangial cells. Studies were performed in a mouse mesangial cell line (TKGM) and two cell clones. Ribonuclease protection assay and Western blot analysis demonstrated that TKGM cells expressed mdr1 and mdr3, the isoforms responsible for multidrug resistance. TKGM-F12 cells coexpressed mdr1 and mdr3 whereas TKGM-G2 cells expressed only mdr1. The drug transport function, measured by rhodamine 123 (R-123) efflux, was smaller in TKGM-F12 than in TKGM-G2 cells. The PGP substrates adriamycin, cyclosporin A, vinblastine, and verapamil inhibited R-123 transport in TKGM and TKGM-G2 cells. In the cells studied, PGP conferred some resistance to adriamycin; concomitant exposure to adriamycin with another PGP substrate impaired cell growth. The differential expression of mdr1 and mdr3 in mouse mesangial cell clones, the ability of mdr1 PGP to transport R-123, and the impairment of PGP-mediated transport in TKGM-F12 cells, coexpressing mdr1 and mdr3 products, are demonstrated. PGP may play a physiological role in mesangial cells.
Insights
P-glycoprotein (PGP) is present in mouse mesangial cells and transports xenobiotics. Its expression and function were studied, revealing PGP may have a physiological role in these kidney cells.
Area of Science:
- Nephrology
- Molecular Biology
- Pharmacology
Background:
- P-glycoprotein (PGP) is known to cause multidrug resistance in cancer cells.
- PGP is expressed in mouse kidney proximal tubule and mesangium.
Purpose of the Study:
- To investigate the expression and xenobiotic transport function of PGP in mouse mesangial cells.
- To determine the role of PGP isoforms (mdr1 and mdr3) in mesangial cell drug transport.
Main Methods:
- Utilized a mouse mesangial cell line (TKGM) and two derived cell clones.
- Employed ribonuclease protection assay and Western blot analysis to detect mdr1 and mdr3 expression.
- Assessed drug transport function via rhodamine 123 (R-123) efflux assays.
Main Results:
- TKGM cells expressed both mdr1 and mdr3 isoforms.
- TKGM-F12 cells coexpressed mdr1 and mdr3, while TKGM-G2 cells expressed only mdr1.
- R-123 efflux was lower in TKGM-F12 cells compared to TKGM-G2 cells, indicating differential PGP function.
- PGP substrates inhibited R-123 transport, and PGP conferred some resistance to adriamycin.
Conclusions:
- Mouse mesangial cells express functional PGP, with differential expression of mdr1 and mdr3 isoforms.
- PGP-mediated xenobiotic transport occurs in mesangial cells.
- PGP may play a physiological role in mesangial cell function and drug handling within the kidney.