title: AKAP150-dependent cooperative TRPV4 channel gating is central to endothelium-dependent vasodilation and is disrupted in hypertension.
abstract: Endothelial cell dysfunction, characterized by a diminished response to endothelial cell-dependent vasodilators, is a hallmark of hypertension. TRPV4 channels play a major role in endothelial-dependent vasodilation, a function mediated by local Ca(2+) influx through clusters of functionally coupled TRPV4 channels rather than by a global increase in endothelial cell Ca(2+). We showed that stimulation of muscarinic acetylcholine receptors on endothelial cells of mouse arteries exclusively activated TRPV4 channels that were localized at myoendothelial projections (MEPs), specialized regions of endothelial cells that contact smooth muscle cells. Muscarinic receptor-mediated activation of TRPV4 depended on protein kinase C (PKC) and the PKC-anchoring protein AKAP150, which was concentrated at MEPs. Cooperative opening of clustered TRPV4 channels specifically amplified Ca(2+) influx at MEPs. Cooperativity of TRPV4 channels at non-MEP sites was much lower, and cooperativity at MEPs was greatly reduced by chelation of intracellular Ca(2+) or AKAP150 knockout, suggesting that Ca(2+) entering through adjacent channels underlies the AKAP150-dependent potentiation of TRPV4 activity. In a mouse model of angiotensin II-induced hypertension, MEP localization of AKAP150 was disrupted, muscarinic receptor stimulation did not activate TRPV4 channels, cooperativity among TRPV4 channels at MEPs was weaker, and vasodilation in response to muscarinic receptor stimulation was reduced. Thus, endothelial-dependent dilation of resistance arteries is enabled by MEP-localized AKAP150, which ensures the proximity of PKC to TRPV4 channels and the coupled channel gating necessary for efficient communication from endothelial to smooth muscle cells in arteries. Disruption of this molecular assembly may contribute to altered blood flow in hypertension.
authors.affiliation: Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05403, USA.
authors.forename: Swapnil K
authors.initials: SK
authors.lastname: Sonkusare
authors.affiliation: Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05403, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Dalsgaard
authors.affiliation: Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05403, USA.
authors.forename: Adrian D
authors.initials: AD
authors.lastname: Bonev
authors.affiliation: Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05403, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Hill-Eubanks
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Michael I
authors.initials: MI
authors.lastname: Kotlikoff
authors.affiliation: Howard Hughes Medical Institute and Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Scott
authors.affiliation: Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA.
authors.forename: Luis F
authors.initials: LF
authors.lastname: Santana
authors.affiliation: Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05403, USA. Institute of Cardiovascular Sciences, University of Manchester, Manchester M13 9NT, UK. mark.nelson@uvm.edu.
authors.forename: Mark T
authors.initials: MT
authors.lastname: Nelson
mesh_terms: D054758:A Kinase Anchor Proteins / Q000235:genetics / Q000378:metabolism*; D000804:Angiotensin II / Q000009:adverse effects / Q000494:pharmacology; D000818:Animals; D020013:Calcium Signaling; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000473:pathology; D006973:Hypertension / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015640:Ion Channel Gating; D051379:Mice; D018345:Mice, Knockout; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism*; D014662:Vasoconstrictor Agents / Q000009:adverse effects / Q000494:pharmacology; D014664:Vasodilation
chemical_list: D054758:A Kinase Anchor Proteins; C520665:Akap5 protein, mouse; D050916:TRPV Cation Channels; C486576:Trpv4 protein, mouse; D014662:Vasoconstrictor Agents; D000804:Angiotensin II