Hypothermia increases aquaporin 4 (AQP4) plasma membrane abundance in human primary cortical astrocytes via a calcium/transient receptor potential vanilloid 4 (TRPV4)- and calmodulin-mediated mechanism


Human aquaporin 4 (AQP4) is the primary water channel protein in brain astrocytes. Hypothermia is known to cause astrocyte swelling in culture, but the precise role of AQP4 in this process is unknown. Primary human cortical astrocytes were cultured under hypothermic (32 °C) or normothermic (37 °C) conditions. AQP4 transcript, total protein and surface-localized protein were quantified using RT-qPCR, sandwich ELISA with whole cell lysates or cell surface biotinylation, followed by ELISA analysis of the surface-localized protein, respectively. Four-hour mild hypothermic treatment increased the surface localization of AQP4 in human astrocytes to 155 ± 4% of normothermic controls, despite no change in total protein expression levels. The hypothermia-mediated increase in AQP4 surface abundance on human astrocytes was blocked using either calmodulin antagonist (trifluoperazine, TFP); TRPV4 antagonist, HC-067047 or calcium chelation using EGTA-AM. The TRPV4 agonist (GSK1016790A) mimicked the effect of hypothermia compared with untreated normothermic astrocytes. Hypothermia led to an increase in surface localization of AQP4 in human astrocytes through a mechanism likely dependent on the TRPV4 calcium channel and calmodulin activation. Understanding the effects of hypothermia on astrocytic AQP4 cell surface expression may help develop new treatments for brain swelling based on an in-depth mechanistic understanding of AQP4 translocation.

Publication DOI: https://doi.org/10.1111/ejn.13723
Divisions: College of Health & Life Sciences > School of Biosciences
College of Health & Life Sciences
College of Health & Life Sciences > Chronic and Communicable Conditions
College of Health & Life Sciences > School of Biosciences > Cell & Tissue Biomedical Research
College of Health & Life Sciences > School of Biosciences > Cellular and Molecular Biomedicine
Additional Information: © The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. Funding: Sheffield Hallam University, University of Wolverhampton, School of Life and Health Sciences Aston University and the HCED/Iraq grant number GD-13-3 (M Salman.
Uncontrolled Keywords: TRPV4 ,aquaporin 4 ,astrocyte ,calcium ,calmodulin ,mild therapeutic hypothermia
Publication ISSN: 1460-9568
Last Modified: 17 Jun 2024 07:28
Date Deposited: 23 Oct 2017 16:15
Full Text Link: http://onlineli ... .13723/abstract
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PURE Output Type: Article
Published Date: 2017-10-13
Published Online Date: 2017-10-13
Accepted Date: 2017-09-15
Authors: Salman, Mootaz M.
Kitchen, Philip (ORCID Profile 0000-0002-1558-4673)
Woodroofe, M. Nicola
Brown, James E. (ORCID Profile 0000-0002-3504-7373)
Bill, Roslyn M (ORCID Profile 0000-0003-1331-0852)
Conner, Alex C.
Conner, Matthew T.


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