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Updated: Aug 13, 2026
Isolation and Transplantation of Different Aged Murine Thymic Grafts.
Published on: May 13, 2015
In vivo and in vitro modulation of MDR molecules in murine thymocytes
Daniela F P Leite1, Juliana Echevarria-Lima, Leonardo T Salgado
1Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Brazil.
Abstract:
P-glycoprotein (Pgp/ABCB1) and multidrug resistance related protein 1 (MRP1/ABCC1) were first described in multidrug resistant tumor cells. It is presently known that both proteins are also expressed in a variety of normal cells, including lymphocytes. ABCB1 activity has already been detected in subpopulations of murine thymocytes, but there was little information on the expression or activity of ABCC1 in these cells. The present work studied in mice the expression of both proteins by RT-PCR and immunofluorescence. It was possible to identify the presence of ABCB1 and to detect the expression of ABCC1 in these cells. The functional activities of these proteins were also studied in vivo and in vitro measuring the extrusion of fluorescent dyes in association with MDR modulators. Cyclosporine A, verapamil and trifluoperazine inhibited the activity of thymic ABCB1. Indomethacin, probenecid and MK571 were effective in inhibiting ABCC1 activity by thymic cells. ABCB1 was only active in a small percentage of thymocytes being present in the immature double negative (not CD4 nor CD8) subpopulation and the mature single positive (CD4 or CD8) subpopulations. The functional activity of ABCC1, on the other hand, was more homogeneously distributed being found in all thymocyte subpopulations. Possible physiological roles for these transporters on thymocytes are discussed.
Insights
This study investigated P-glycoprotein (ABCB1) and multidrug resistance related protein 1 (ABCC1) in mouse thymocytes. Both transporters are expressed, with ABCB1 found in specific subpopulations and ABCC1 more broadly, suggesting diverse physiological roles.
Area of Science:
- Immunology
- Cell Biology
- Pharmacology
Background:
- P-glycoprotein (Pgp/ABCB1) and multidrug resistance related protein 1 (MRP1/ABCC1) are efflux transporters.
- These transporters are known to be expressed in normal cells, including lymphocytes.
- Previous studies indicated ABCB1 activity in murine thymocytes, but ABCC1 expression and function were less understood.
Purpose of the Study:
- To investigate the expression and functional activity of ABCB1 and ABCC1 in mouse thymocytes.
- To determine the distribution of these transporters across different thymocyte subpopulations.
- To explore potential physiological roles of these transporters in thymocytes.
Main Methods:
- Quantitative analysis of ABCB1 and ABCC1 expression using RT-PCR and immunofluorescence.
- In vivo and in vitro functional assays measuring fluorescent dye extrusion.
- Assessment of transporter activity using specific modulators like Cyclosporine A, verapamil, trifluoperazine, indomethacin, probenecid, and MK571.
Main Results:
- ABCB1 and ABCC1 were both detected in mouse thymocytes.
- ABCB1 activity was primarily observed in immature double-negative and mature single-positive thymocyte subpopulations.
- ABCC1 functional activity was more uniformly distributed across all thymocyte subpopulations.
Conclusions:
- Both ABCB1 and ABCC1 are functionally active in mouse thymocytes.
- The differential distribution suggests distinct roles for these transporters in thymocyte development and function.
- Further research is warranted to elucidate the specific physiological significance of ABCB1 and ABCC1 in the thymus.
