PIP2 depletion promotes TRPV4 channel activity in mouse brain capillary endothelial cells
- University of Vermont, United States
Abstract
We recently reported that the inward-rectifier Kir2.1 channel in brain capillary endothelial cells (cECs) plays a major role in neurovascular coupling (NVC) by mediating a neuronal activity-dependent, propagating vasodilatory (hyperpolarizing) signal. We further demonstrated that Kir2.1 activity is suppressed by depletion of plasma membrane phosphatidylinositol 4,5-bisphosphate (PIP2). Whether cECs express depolarizing channels that intersect with Kir2.1-mediated signaling remains unknown. Here, we report that Ca2+/Na+-permeable TRPV4 (transient receptor potential vanilloid 4) channels are expressed in cECs and are tonically inhibited by PIP2. We further demonstrate that depletion of PIP2 by agonists, including putative NVC mediators, that promote PIP2 hydrolysis by signaling through Gq-protein-coupled receptors (GqPCRs) caused simultaneous disinhibition of TRPV4 channels and suppression of Kir2.1 channels. These findings collectively support the concept that GqPCR activation functions as a molecular switch to favor capillary TRPV4 activity over Kir2.1 signaling, an observation with potentially profound significance for the control of cerebral blood flow.
Data availability
All data generated or analyzed during this study are included in the manuscript and supporting source data files.
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A molecular atlas of cell types and zonation in the brain vasculature.The searchable database is publicly available at http://betsholtzlab.org/VascularSingleCells/database.html. Accession numbers are GSE98816, GSE99058 and GSE99235.
Article and author information
Author details
Funding
American Heart Association (Postdoctoral fellowship 17POST33650030)
- Osama F Harraz
National Institutes of Health (R37-DK-053832)
- Mark T Nelson
National Institutes of Health (7UM-HL-1207704)
- Mark T Nelson
National Institutes of Health (R01-HL-131181)
- Mark T Nelson
American Heart Association (Scientist Development Grant 17SDG33670237)
- Thomas Andrew Longden
National Institutes of Health (P01-HL-095488)
- Mark T Nelson
National Institutes of Health (4P20 GM103644/4-5 to the Vermont Center on Behavior and Health)
- Thomas Andrew Longden
The Totman Medical Research Trust
- Mark T Nelson
Fondation Leducq
- Mark T Nelson
European Union's Horizon 2020 Research and Innovation Programme (Grant agreement No 666881 SVDs@target)
- Mark T Nelson
National Institutes of Health (P30-GM-103498 to the COBRE imaging facility at UVM College of Medicine)
- Mark T Nelson
National Institutes of Health (R01-HL-121706)
- Mark T Nelson
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All procedures involving animals received prior approval from the University of Vermont Institutional Animal Care and Use Committee (IACUC, protocol # 14-063 and 16-010). Animals were euthanized by intraperitoneal injection of sodium pentobarbital (100 mg/kg) followed by rapid decapitation. Every effort was made to minimize suffering of animal subjects.
Copyright
© 2018, Harraz et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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