The experiments in this application will test the hypothesis that clusters of voltage-gated L-type CaV1.2 channels are capable of undergoing coordinated openings (""""""""coupled gating""""""""), amplifying Ca2+ influx into arterial smooth muscle. A key discovery is that Ca2+ influx via coupled CaV1.2 channels plays a critical role in excitation-contraction (EC) coupling and excitation-transcription (ET) coupling in arterial myocytes. Preliminary data suggest that association of CaV1.2 channels with the anchoring protein AKAP150 is necessary for coupled gating activity in these cells. The significance of these findings is underscored by the observation that the frequency of coupled CaV1.2 gating events increases in arterial smooth muscle during hypertension and that loss of AKAP150 protects against coupled gating and hypertension. The project has two specific aims designed to investigate the mechanisms and physiological implications of these findings.
Specific aim 1 is to test the hypothesis that coupled gating of CaV1.2 channels amplifies Ca2+ influx in arterial myocytes.
Specific aim 2 is to test the hypothesis that AKAP150 is required for increased coupled CaV1.2 channel activity and the induction of arterial dysfunction during the development of hypertension. The methods that will be used to achieve these aims include patch-clamp electrophysiology, optical clamping, light- and chemically-induced dynamic targeting of kinases to cellular membranes, light-induced activation of adrenergic signaling (i.e., optogenetics), confocal, and TIRF microscopy. Experiments will involve new transgenic, knock in, and knock out mice. This work will generate fundamental information on the mechanisms by which AKAP150 and CaV1.2 channels control of excitability, gene expression, and EC coupling in vascular smooth muscle under physiological and pathological conditions.

Public Health Relevance

Recent data from the Centers for Disease Control and Prevention suggest that, in the USA, nearly 33% of adults ages 20 and older suffer of hypertension, a clinical syndrome characterized by increased vascular tone. However, the mechanisms underlying these pathological changes in vascular function are poorly understood. The experiments proposed in this application have important implications for public health because they investigate the mechanisms by which a new Ca2+ signaling modality regulates the function of vascular smooth muscle under normal conditions and during the development of hypertension. The results of the proposed work may lead to the development of rational strategies for the treatment of hypertension.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL085870-08
Application #
8627639
Study Section
Hypertension and Microcirculation Study Section (HM)
Program Officer
OH, Youngsuk
Project Start
2006-07-01
Project End
2017-02-28
Budget Start
2014-03-01
Budget End
2015-02-28
Support Year
8
Fiscal Year
2014
Total Cost
$726,150
Indirect Cost
$256,150
Name
University of Washington
Department
Physiology
Type
Schools of Medicine
DUNS #
605799469
City
Seattle
State
WA
Country
United States
Zip Code
98195
Nieves-Cintrón, Madeline; Syed, Arsalan U; Buonarati, Olivia R et al. (2017) Impaired BKCa channel function in native vascular smooth muscle from humans with type 2 diabetes. Sci Rep 7:14058
Tajada, Sendoa; Moreno, Claudia M; O'Dwyer, Samantha et al. (2017) Distance constraints on activation of TRPV4 channels by AKAP150-bound PKC? in arterial myocytes. J Gen Physiol 149:639-659
Vivas, Oscar; Moreno, Claudia M; Santana, Luis F et al. (2017) Proximal clustering between BK and CaV1.3 channels promotes functional coupling and BK channel activation at low voltage. Elife 6:
Ghosh, D; Syed, A U; Prada, M P et al. (2017) Calcium Channels in Vascular Smooth Muscle. Adv Pharmacol 78:49-87
Gentil, Benoit J; O'Ferrall, Erin; Chalk, Colin et al. (2017) A New Mutation in FIG4 Causes a Severe Form of CMT4J Involving TRPV4 in the Pathogenic Cascade. J Neuropathol Exp Neurol 76:789-799
Nieves-Cintrón, Madeline; Hirenallur-Shanthappa, Dinesh; Nygren, Patrick J et al. (2016) AKAP150 participates in calcineurin/NFAT activation during the down-regulation of voltage-gated K(+) currents in ventricular myocytes following myocardial infarction. Cell Signal 28:733-40
Dickson, Eamonn J; Jensen, Jill B; Vivas, Oscar et al. (2016) Dynamic formation of ER-PM junctions presents a lipid phosphatase to regulate phosphoinositides. J Cell Biol 213:33-48
Moreno, Claudia M; Dixon, Rose E; Tajada, Sendoa et al. (2016) Ca(2+) entry into neurons is facilitated by cooperative gating of clustered CaV1.3 channels. Elife 5:
Dixon, Rose E; Moreno, Claudia M; Yuan, Can et al. (2015) Graded Ca²?/calmodulin-dependent coupling of voltage-gated CaV1.2 channels. Elife 4:
Nystoriak, Matthew A; Nieves-Cintrón, Madeline; Nygren, Patrick J et al. (2014) AKAP150 contributes to enhanced vascular tone by facilitating large-conductance Ca2+-activated K+ channel remodeling in hyperglycemia and diabetes mellitus. Circ Res 114:607-15

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