Abcg2a is the functional homolog of human ABCG2 expressed at the zebrafish blood–brain barrier
Abstract Background A principal protective component of the mammalian blood–brain barrier (BBB) is the high expression of the multidrug efflux transporters P-glycoprotein (P-gp, encoded by ABCB1) and ABCG2 (encoded by ABCG2) on the lumenal surface of endothelial cells. The zebrafish P-gp homolog Abc...
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BMC
2024-03-01
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| Series: | Fluids and Barriers of the CNS |
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| Online Access: | https://doi.org/10.1186/s12987-024-00529-5 |
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| author | Joanna R. Thomas William J. E. Frye Robert W. Robey Andrew C. Warner Donna Butcher Jennifer L. Matta Tamara C. Morgan Elijah F. Edmondson Paula B. Salazar Suresh V. Ambudkar Michael M. Gottesman |
| author_facet | Joanna R. Thomas William J. E. Frye Robert W. Robey Andrew C. Warner Donna Butcher Jennifer L. Matta Tamara C. Morgan Elijah F. Edmondson Paula B. Salazar Suresh V. Ambudkar Michael M. Gottesman |
| author_sort | Joanna R. Thomas |
| collection | DOAJ |
| description | Abstract Background A principal protective component of the mammalian blood–brain barrier (BBB) is the high expression of the multidrug efflux transporters P-glycoprotein (P-gp, encoded by ABCB1) and ABCG2 (encoded by ABCG2) on the lumenal surface of endothelial cells. The zebrafish P-gp homolog Abcb4 is expressed at the BBB and phenocopies human P-gp. Comparatively little is known about the four zebrafish homologs of the human ABCG2 gene: abcg2a, abcg2b, abcg2c, and abcg2d. Here we report the functional characterization and brain tissue distribution of zebrafish ABCG2 homologs. Methods To determine substrates of the transporters, we stably expressed each in HEK-293 cells and performed cytotoxicity and fluorescent efflux assays with known ABCG2 substrates. To assess the expression of transporter homologs, we used a combination of RNAscope in situ hybridization probes and immunohistochemistry to stain paraffin-embedded sections of adult and larval zebrafish. Results We found Abcg2a had the greatest substrate overlap with ABCG2, and Abcg2d appeared to be the least functionally similar. We identified abcg2a as the only homolog expressed at the adult and larval zebrafish BBB, based on its localization to claudin-5 positive brain vasculature. Conclusions These results demonstrate the conserved function of zebrafish Abcg2a and suggest that zebrafish may be an appropriate model organism for studying the role of ABCG2 at the BBB. |
| format | Article |
| id | doaj-art-9a080e0214994889a3107bc9b1dea9d1 |
| institution | Kabale University |
| issn | 2045-8118 |
| language | English |
| publishDate | 2024-03-01 |
| publisher | BMC |
| record_format | Article |
| series | Fluids and Barriers of the CNS |
| spelling | doaj-art-9a080e0214994889a3107bc9b1dea9d12025-01-05T12:43:24ZengBMCFluids and Barriers of the CNS2045-81182024-03-0121111210.1186/s12987-024-00529-5Abcg2a is the functional homolog of human ABCG2 expressed at the zebrafish blood–brain barrierJoanna R. Thomas0William J. E. Frye1Robert W. Robey2Andrew C. Warner3Donna Butcher4Jennifer L. Matta5Tamara C. Morgan6Elijah F. Edmondson7Paula B. Salazar8Suresh V. Ambudkar9Michael M. Gottesman10Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of HealthLaboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of HealthLaboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of HealthMolecular Histopathology Laboratory, Frederick National Laboratory for Cancer ResearchMolecular Histopathology Laboratory, Frederick National Laboratory for Cancer ResearchMolecular Histopathology Laboratory, Frederick National Laboratory for Cancer ResearchMolecular Histopathology Laboratory, Frederick National Laboratory for Cancer ResearchMolecular Histopathology Laboratory, Frederick National Laboratory for Cancer ResearchLaboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of HealthLaboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of HealthLaboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of HealthAbstract Background A principal protective component of the mammalian blood–brain barrier (BBB) is the high expression of the multidrug efflux transporters P-glycoprotein (P-gp, encoded by ABCB1) and ABCG2 (encoded by ABCG2) on the lumenal surface of endothelial cells. The zebrafish P-gp homolog Abcb4 is expressed at the BBB and phenocopies human P-gp. Comparatively little is known about the four zebrafish homologs of the human ABCG2 gene: abcg2a, abcg2b, abcg2c, and abcg2d. Here we report the functional characterization and brain tissue distribution of zebrafish ABCG2 homologs. Methods To determine substrates of the transporters, we stably expressed each in HEK-293 cells and performed cytotoxicity and fluorescent efflux assays with known ABCG2 substrates. To assess the expression of transporter homologs, we used a combination of RNAscope in situ hybridization probes and immunohistochemistry to stain paraffin-embedded sections of adult and larval zebrafish. Results We found Abcg2a had the greatest substrate overlap with ABCG2, and Abcg2d appeared to be the least functionally similar. We identified abcg2a as the only homolog expressed at the adult and larval zebrafish BBB, based on its localization to claudin-5 positive brain vasculature. Conclusions These results demonstrate the conserved function of zebrafish Abcg2a and suggest that zebrafish may be an appropriate model organism for studying the role of ABCG2 at the BBB.https://doi.org/10.1186/s12987-024-00529-5ZebrafishABCG2Blood–brain barrierDrug resistance |
| spellingShingle | Joanna R. Thomas William J. E. Frye Robert W. Robey Andrew C. Warner Donna Butcher Jennifer L. Matta Tamara C. Morgan Elijah F. Edmondson Paula B. Salazar Suresh V. Ambudkar Michael M. Gottesman Abcg2a is the functional homolog of human ABCG2 expressed at the zebrafish blood–brain barrier Fluids and Barriers of the CNS Zebrafish ABCG2 Blood–brain barrier Drug resistance |
| title | Abcg2a is the functional homolog of human ABCG2 expressed at the zebrafish blood–brain barrier |
| title_full | Abcg2a is the functional homolog of human ABCG2 expressed at the zebrafish blood–brain barrier |
| title_fullStr | Abcg2a is the functional homolog of human ABCG2 expressed at the zebrafish blood–brain barrier |
| title_full_unstemmed | Abcg2a is the functional homolog of human ABCG2 expressed at the zebrafish blood–brain barrier |
| title_short | Abcg2a is the functional homolog of human ABCG2 expressed at the zebrafish blood–brain barrier |
| title_sort | abcg2a is the functional homolog of human abcg2 expressed at the zebrafish blood brain barrier |
| topic | Zebrafish ABCG2 Blood–brain barrier Drug resistance |
| url | https://doi.org/10.1186/s12987-024-00529-5 |
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