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P2X4 receptors in activated C8-B4 cells of cerebellar microglial origin

We investigated the properties and regulation of P2X receptors in immortalized C8-B4 cells of cerebellar microglial origin. Resting C8-B4 cells expressed virtually no functional P2X receptors, but largely increased functional expression of P2X4 receptors within 2–6 h of entering the activated state....

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Autores principales: Toulme, Estelle, Garcia, Angie, Samways, Damien, Egan, Terrance M., Carson, Monica J., Khakh, Baljit S.
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2847917/
https://www.ncbi.nlm.nih.gov/pubmed/20231374
http://dx.doi.org/10.1085/jgp.200910336
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author Toulme, Estelle
Garcia, Angie
Samways, Damien
Egan, Terrance M.
Carson, Monica J.
Khakh, Baljit S.
author_facet Toulme, Estelle
Garcia, Angie
Samways, Damien
Egan, Terrance M.
Carson, Monica J.
Khakh, Baljit S.
author_sort Toulme, Estelle
collection PubMed
description We investigated the properties and regulation of P2X receptors in immortalized C8-B4 cells of cerebellar microglial origin. Resting C8-B4 cells expressed virtually no functional P2X receptors, but largely increased functional expression of P2X4 receptors within 2–6 h of entering the activated state. Using real-time polymerase chain reaction, we found that P2X4 transcripts were increased during the activated state by 2.4-fold, but this increase was not reflected by a parallel increase in total P2X4 proteins. In resting C8-B4 cells, P2X4 subunits were mainly localized within intracellular compartments, including lysosomes. We found that cell surface P2X4 receptor levels increased by ∼3.5-fold during the activated state. This change was accompanied by a decrease in the lysosomal pool of P2X4 proteins. We next exploited our findings with C8-B4 cells to investigate the mechanism by which antidepressants reduce P2X4 responses. We found little evidence to suggest that several antidepressants were antagonists of P2X4 receptors in C8-B4 cells. However, we found that moderate concentrations of the same antidepressants reduced P2X4 responses in activated microglia by affecting lysosomal function, which indirectly reduced cell surface P2X4 levels. In summary, our data suggest that activated C8-B4 cells express P2X4 receptors when the membrane insertion of these proteins by lysosomal secretion exceeds their removal, and that antidepressants indirectly reduce P2X4 responses by interfering with lysosomal trafficking.
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spelling pubmed-28479172010-10-01 P2X4 receptors in activated C8-B4 cells of cerebellar microglial origin Toulme, Estelle Garcia, Angie Samways, Damien Egan, Terrance M. Carson, Monica J. Khakh, Baljit S. J Gen Physiol Article We investigated the properties and regulation of P2X receptors in immortalized C8-B4 cells of cerebellar microglial origin. Resting C8-B4 cells expressed virtually no functional P2X receptors, but largely increased functional expression of P2X4 receptors within 2–6 h of entering the activated state. Using real-time polymerase chain reaction, we found that P2X4 transcripts were increased during the activated state by 2.4-fold, but this increase was not reflected by a parallel increase in total P2X4 proteins. In resting C8-B4 cells, P2X4 subunits were mainly localized within intracellular compartments, including lysosomes. We found that cell surface P2X4 receptor levels increased by ∼3.5-fold during the activated state. This change was accompanied by a decrease in the lysosomal pool of P2X4 proteins. We next exploited our findings with C8-B4 cells to investigate the mechanism by which antidepressants reduce P2X4 responses. We found little evidence to suggest that several antidepressants were antagonists of P2X4 receptors in C8-B4 cells. However, we found that moderate concentrations of the same antidepressants reduced P2X4 responses in activated microglia by affecting lysosomal function, which indirectly reduced cell surface P2X4 levels. In summary, our data suggest that activated C8-B4 cells express P2X4 receptors when the membrane insertion of these proteins by lysosomal secretion exceeds their removal, and that antidepressants indirectly reduce P2X4 responses by interfering with lysosomal trafficking. The Rockefeller University Press 2010-04 /pmc/articles/PMC2847917/ /pubmed/20231374 http://dx.doi.org/10.1085/jgp.200910336 Text en © 2010 Toulme et al. This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/).
spellingShingle Article
Toulme, Estelle
Garcia, Angie
Samways, Damien
Egan, Terrance M.
Carson, Monica J.
Khakh, Baljit S.
P2X4 receptors in activated C8-B4 cells of cerebellar microglial origin
title P2X4 receptors in activated C8-B4 cells of cerebellar microglial origin
title_full P2X4 receptors in activated C8-B4 cells of cerebellar microglial origin
title_fullStr P2X4 receptors in activated C8-B4 cells of cerebellar microglial origin
title_full_unstemmed P2X4 receptors in activated C8-B4 cells of cerebellar microglial origin
title_short P2X4 receptors in activated C8-B4 cells of cerebellar microglial origin
title_sort p2x4 receptors in activated c8-b4 cells of cerebellar microglial origin
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2847917/
https://www.ncbi.nlm.nih.gov/pubmed/20231374
http://dx.doi.org/10.1085/jgp.200910336
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