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Spatial and temporal dissociation of AQP4 and Kir4.1 expression during induction of refractive errors

PURPOSE: Spatial co-localization of aquaporin water channels (AQP4) and inwardly rectifying potassium ion channels (Kir4.1) on the endfeet regions of glial cells has been suggested as the basis of functionally interrelated mechanisms of osmoregulation in brain edema. The aim of this study was to inv...

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Autores principales: Goodyear, Melinda J., Crewther, Sheila G., Murphy, Melanie J., Giummarra, Loretta, Hazi, Agnes, Junghans, Barbara M., Crewther, David P.
Formato: Texto
Lenguaje:English
Publicado: Molecular Vision 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2927440/
https://www.ncbi.nlm.nih.gov/pubmed/20806048
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author Goodyear, Melinda J.
Crewther, Sheila G.
Murphy, Melanie J.
Giummarra, Loretta
Hazi, Agnes
Junghans, Barbara M.
Crewther, David P.
author_facet Goodyear, Melinda J.
Crewther, Sheila G.
Murphy, Melanie J.
Giummarra, Loretta
Hazi, Agnes
Junghans, Barbara M.
Crewther, David P.
author_sort Goodyear, Melinda J.
collection PubMed
description PURPOSE: Spatial co-localization of aquaporin water channels (AQP4) and inwardly rectifying potassium ion channels (Kir4.1) on the endfeet regions of glial cells has been suggested as the basis of functionally interrelated mechanisms of osmoregulation in brain edema. The aim of this study was to investigate the spatial and temporal changes in the expression of AQP4 and Kir4.1 channels in an avascular retina during the first week of the optical induction of refractive errors. METHODS: Three-day-old hatchling chicks were randomly assigned to three groups and either did not wear lenses or were monocularly goggled with ±10D lenses for varying times up to 7 days before biometric assessment. Retinal tissue was prepared either for western blot analysis to show the presence of the AQP4 and Kir4.1 protein in the chick retina or for immunolocalization using AQP4 and Kir4.1 antibodies to determine the regional distribution and intensity of labeling during the induction of refractive errors. RESULTS: As expected, ultrasonography demonstrated that all eyes showed rapid elongation post hatching. Negative lens-wearing eyes elongated faster than fellow eyes or normal non goggled eyes and became progressively more myopic with time post lensing. Positive lens-wearing eyes showed reduced ocular growth compared to normal controls and developed a hyperopic refraction. Quantitative immunohistochemistry revealed the upregulation of AQP4 channel expression on Müller cells in the retinal nerve fiber layer during the first 2 days of negative lens wear. Kir4.1 channel upregulation in the inner plexiform layer was only found on day 4 of positive lens wear during the development of refractive hyperopia. CONCLUSIONS: These results indicate that the expression of AQP4 and Kir4.1 channels on Müller cells is associated with the changes in ocular volume seen during the induction of refractive errors. However, the sites of greatest expression and the temporal pattern of the upregulation of AQP4 and Kir4.1 were dissimilar, indicating a dissociation of AQP4 and Kir4.1 function during refractive error development. Increased AQP4 expression in the nerve fiber layer is suggested to contribute to the rapid axial elongation and movement of fluid into the vitreous cavity in the presence of minus lenses; whereas, upregulation of Kir4.1 channels appears to play a role in limiting axial elongation in the presence of plus lenses.
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spelling pubmed-29274402010-08-30 Spatial and temporal dissociation of AQP4 and Kir4.1 expression during induction of refractive errors Goodyear, Melinda J. Crewther, Sheila G. Murphy, Melanie J. Giummarra, Loretta Hazi, Agnes Junghans, Barbara M. Crewther, David P. Mol Vis Research Article PURPOSE: Spatial co-localization of aquaporin water channels (AQP4) and inwardly rectifying potassium ion channels (Kir4.1) on the endfeet regions of glial cells has been suggested as the basis of functionally interrelated mechanisms of osmoregulation in brain edema. The aim of this study was to investigate the spatial and temporal changes in the expression of AQP4 and Kir4.1 channels in an avascular retina during the first week of the optical induction of refractive errors. METHODS: Three-day-old hatchling chicks were randomly assigned to three groups and either did not wear lenses or were monocularly goggled with ±10D lenses for varying times up to 7 days before biometric assessment. Retinal tissue was prepared either for western blot analysis to show the presence of the AQP4 and Kir4.1 protein in the chick retina or for immunolocalization using AQP4 and Kir4.1 antibodies to determine the regional distribution and intensity of labeling during the induction of refractive errors. RESULTS: As expected, ultrasonography demonstrated that all eyes showed rapid elongation post hatching. Negative lens-wearing eyes elongated faster than fellow eyes or normal non goggled eyes and became progressively more myopic with time post lensing. Positive lens-wearing eyes showed reduced ocular growth compared to normal controls and developed a hyperopic refraction. Quantitative immunohistochemistry revealed the upregulation of AQP4 channel expression on Müller cells in the retinal nerve fiber layer during the first 2 days of negative lens wear. Kir4.1 channel upregulation in the inner plexiform layer was only found on day 4 of positive lens wear during the development of refractive hyperopia. CONCLUSIONS: These results indicate that the expression of AQP4 and Kir4.1 channels on Müller cells is associated with the changes in ocular volume seen during the induction of refractive errors. However, the sites of greatest expression and the temporal pattern of the upregulation of AQP4 and Kir4.1 were dissimilar, indicating a dissociation of AQP4 and Kir4.1 function during refractive error development. Increased AQP4 expression in the nerve fiber layer is suggested to contribute to the rapid axial elongation and movement of fluid into the vitreous cavity in the presence of minus lenses; whereas, upregulation of Kir4.1 channels appears to play a role in limiting axial elongation in the presence of plus lenses. Molecular Vision 2010-08-14 /pmc/articles/PMC2927440/ /pubmed/20806048 Text en Copyright © 2010 Molecular Vision. http://creativecommons.org/licenses/by/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Goodyear, Melinda J.
Crewther, Sheila G.
Murphy, Melanie J.
Giummarra, Loretta
Hazi, Agnes
Junghans, Barbara M.
Crewther, David P.
Spatial and temporal dissociation of AQP4 and Kir4.1 expression during induction of refractive errors
title Spatial and temporal dissociation of AQP4 and Kir4.1 expression during induction of refractive errors
title_full Spatial and temporal dissociation of AQP4 and Kir4.1 expression during induction of refractive errors
title_fullStr Spatial and temporal dissociation of AQP4 and Kir4.1 expression during induction of refractive errors
title_full_unstemmed Spatial and temporal dissociation of AQP4 and Kir4.1 expression during induction of refractive errors
title_short Spatial and temporal dissociation of AQP4 and Kir4.1 expression during induction of refractive errors
title_sort spatial and temporal dissociation of aqp4 and kir4.1 expression during induction of refractive errors
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2927440/
https://www.ncbi.nlm.nih.gov/pubmed/20806048
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