Related Experiment Video
Updated: Aug 17, 2026
Purification of Mouse Brain Vessels
Published on: November 10, 2015
Expression of various multidrug resistance-associated protein (MRP) homologues in brain microvessel endothelial cells
1Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA.
Abstract:
Multidrug resistance-associated protein (MRP) actively transports a broad range of anionic compounds out of the cell. To date, six different homologues of MRP (i.e. MRP1-MRP6) have been identified. The current study examines the expression of the various MRP homologues in both primary cultured bovine brain microvessel endothelial cells (BBMEC) and the capillary-enriched fraction from bovine brain homogenates. RT-PCR analysis demonstrated the presence of MRP1, MRP4, MRP5 and MRP6 in both BBMEC and the capillary-enriched fractions of brain homogenates. While low levels of MRP3 were detected in the BBMEC, it was not observed in the capillary-enriched fraction. In addition, RT-PCR and Western blot studies indicated an absence of MRP2 expression in both blood-brain barrier preparations. The presence of several different MRP homologues in the brain microvessel endothelial cells may be important in controlling the permeability of the blood-brain barrier to organic anions.
Insights
Multidrug resistance-associated proteins (MRPs) transport compounds out of cells. This study found MRP1, MRP4, MRP5, and MRP6 are present in bovine brain microvessel endothelial cells, potentially influencing blood-brain barrier permeability.
Area of Science:
- Biochemistry
- Cell Biology
- Neuroscience
Background:
- Multidrug resistance-associated proteins (MRPs) are ATP-binding cassette transporters.
- MRPs efflux a wide range of anionic substrates, influencing drug disposition and cellular protection.
- Six MRP homologues (MRP1-MRP6) have been identified, with varying tissue distribution and functions.
Purpose of the Study:
- To investigate the expression profile of MRP homologues in bovine brain microvessel endothelial cells (BBMEC).
- To determine the presence and localization of MRPs within the bovine blood-brain barrier (BBB).
- To elucidate the potential role of MRPs in regulating BBB permeability to organic anions.
Main Methods:
- Primary cell culture of bovine brain microvessel endothelial cells (BBMEC).
- Preparation of capillary-enriched fractions from bovine brain homogenates.
- Reverse transcription polymerase chain reaction (RT-PCR) for gene expression analysis.
- Western blot analysis for protein expression confirmation.
Main Results:
- RT-PCR detected MRP1, MRP4, MRP5, and MRP6 mRNA in both BBMEC and capillary-enriched fractions.
- Low levels of MRP3 mRNA were found in BBMEC but not in capillary fractions.
- MRP2 mRNA and protein were notably absent in both BBB preparations.
- MRP1, MRP4, MRP5, and MRP6 proteins were confirmed in BBMEC.
Conclusions:
- Bovine brain microvessel endothelial cells express multiple MRP homologues, including MRP1, MRP4, MRP5, and MRP6.
- The absence of MRP2 suggests a specific role for other MRPs in brain microvasculature.
- The identified MRPs likely play a significant role in controlling the transport of organic anions across the blood-brain barrier.
