Principal Investigator/Program Director (Last, first, middle): Marrelli, Sean RESEARCH &RELATED Other Project Information 1. * Are Human Subjects Involved? m Yes l No 1.a. If YES to Human Subjects Is the IRB review Pending? m Yes m No IRB Approval Date: Exemption Number: 1 2 3 4 5 6 Human Subject Assurance Number 2. * Are Vertebrate Animals Used? l Yes m No 2.a. If YES to Vertebrate Animals Is the IACUC review Pending? m Yes l No IACUC Approval Date: 07-26-2006 Animal Welfare Assurance Number A3823-01 3. * Is proprietary/privileged information m Yes l No included in the application? 4.a.* Does this project have an actual or potential impact on m Yes l No the environment? 4.b. If yes, please explain: 4.c. If this project has an actual or potential impact on the environment, has an exemption been authorized or an environmental assessment (EA) or environmental impact statement (EIS) been performed? m Yes m No 4.d. If yes, please explain: 5.a.* Does this project involve activities outside the U.S. or m Yes l No partnership with International Collaborators? 5.b. If yes, identify countries: 5.c. Optional Explanation: 6. * Project Summary/Abstract 3685-Project_Summary_and_Abstract__MiamrcehT_y2p0e0:7a.pdpflication/pdf 7. * Project Narrative 2134-Project_Narrative___March_2007.pMdifme Type: application/pdf 8. Bibliography &References Cited 5376-Final_March_2007____BibliographMy_imanedT_yRpefe: raepnpcliecsa.tpiodnf /pdf 9. Facilities &Other Resources 8161-Project_Resources_summary_revisMeidm.pedTf ype: application/pdf 10. Equipment 6927-Equipment_summary.pdf Mime Type: application/pdf Tracking Number: Other Information Page 5 OMB Number: 4040-0001 Expiration Date: 04/30/2008 Principal Investigator/Program Director (Last, first, middle): Marrelli, Sean Adenosine triphosphate (ATP) is a potent regulator of vascular tone in the cerebral circulation. This physiological agonist is released from a variety of sources in the cardiovascular system under normal and pathological conditions. When presented to the endothelium, ATP stimulates artery dilation through multiple pathways including endothelium-derived hyperpolarizing factor (EDHF) mediated mechanisms. Endothelial cell (EC) hyperpolarization plays a crucial role in EDHF mediated dilation and is a fundamental determinant of arterial tone in multiple vascular beds. While the mechanism by which ECs become hyperpolarized by agonists is still poorly defined, several lines of evidence indicate a significant role for activation of endothelial intermediate-conductance KCa (IKCa) channels. IKCa channels are primarily regulated by cytosolic Ca2+ concentration, but the source of the activating Ca2+ is not known. We propose that ATP stimulates Ca2+ influx through endothelial transient receptor potential (TRP) channels which promotes IKCa channel activation with subsequent EC hyperpolarization and artery dilation. Specifically, we propose to:
Aim 1 : Define the role of TRP channels in ATP signaling in cerebrovascular endothelial cells. ATP promotes endothelial Ca2+ influx and subsequent dilation via NO and EDHF dependent mechanisms. In this specific aim we will determine if ATP activates TRP channels to promote Ca2+ influx in cerebrovascular endothelial cells. We will identify the TRP channels expressed in ECs (RT-PCR and immunohistochemistry), measure [Ca2+]i and Ca2+ influx in response to ATP in freshly isolated middle cerebral artery (MCA) ECs and in the ECs of pressurized MCA (Fura 2 dye), and demonstrate the role of the identified TRP channels by pharmacological and RNA silencing techniques (organ culture with siRNA).
Aim 2 : Elucidate the role of TRP channels in IKCa channel activation, EC hyperpolarization, and EDHF-mediated dilation in cerebral arteries. EDHF-mediated dilation of cerebral arteries requires EC Ca2+ influx, IKCa channel activation, and EC hyperpolarization. We will determine the role of Ca2+ influx through TRP channels on IKCa channel activation and EC hyperpolarization. Specifically, we will demonstrate that Ca2+ influx via TRP channels is critical for activation of IKCa channels and subsequent EC hyperpolarization using techniques to measure membrane potential and IKCa channel activation (whole cell patch clamp) in ECs from organ cultured MCA. We will also demonstrate that Ca2+ influx via TRP channels is critical for EDHF-mediated dilation by measuring ATP stimulated dilation in intact organ cultured MCA. These studies should lead to novel therapeutic strategies for controlling blood flow in the brain by defining the role of specific TRP channels in the regulation of EC Ca2+ concentration, EC hyperpolarization, and EDHF-mediated dilation. Project Description Page 6

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
3R01HL088435-02S1
Application #
7839437
Study Section
Vascular Cell and Molecular Biology Study Section (VCMB)
Program Officer
Goldman, Stephen
Project Start
2009-07-15
Project End
2011-06-30
Budget Start
2009-07-15
Budget End
2011-06-30
Support Year
2
Fiscal Year
2009
Total Cost
$214,286
Indirect Cost
Name
Baylor College of Medicine
Department
Anesthesiology
Type
Schools of Medicine
DUNS #
051113330
City
Houston
State
TX
Country
United States
Zip Code
77030
Feketa, Viktor V; Marrelli, Sean P (2015) Systemic Administration of the TRPV3 Ion Channel Agonist Carvacrol Induces Hypothermia in Conscious Rodents. PLoS One 10:e0141994
Cao, Zhijuan; Balasubramanian, Adithya; Marrelli, Sean P (2014) Pharmacologically induced hypothermia via TRPV1 channel agonism provides neuroprotection following ischemic stroke when initiated 90 min after reperfusion. Am J Physiol Regul Integr Comp Physiol 306:R149-56
Kochukov, Mikhail Y; Balasubramanian, Adithya; Abramowitz, Joel et al. (2014) Activation of endothelial transient receptor potential C3 channel is required for small conductance calcium-activated potassium channel activation and sustained endothelial hyperpolarization and vasodilation of cerebral artery. J Am Heart Assoc 3:
Feketa, Viktor V; Zhang, Yi; Cao, Zhijuan et al. (2014) Transient receptor potential melastatin 8 channel inhibition potentiates the hypothermic response to transient receptor potential vanilloid 1 activation in the conscious mouse. Crit Care Med 42:e355-63
Lloyd, Eric E; Pandit, Lavannya M; Crossland, Randy F et al. (2013) Endothelium-dependent relaxations in the aorta from K(2p)6.1 knockout mice. Am J Physiol Regul Integr Comp Physiol 305:R60-7
Feketa, Viktor V; Balasubramanian, Adithya; Flores, Christopher M et al. (2013) Shivering and tachycardic responses to external cooling in mice are substantially suppressed by TRPV1 activation but not by TRPM8 inhibition. Am J Physiol Regul Integr Comp Physiol 305:R1040-50
Crossland, Randy F; Durgan, David J; Lloyd, Eric E et al. (2013) A new rodent model for obstructive sleep apnea: effects on ATP-mediated dilations in cerebral arteries. Am J Physiol Regul Integr Comp Physiol 305:R334-42
Kochukov, M Y; Balasubramanian, A; Noel, R C et al. (2013) Role of TRPC1 and TRPC3 channels in contraction and relaxation of mouse thoracic aorta. J Vasc Res 50:11-20
Senadheera, Sevvandi; Kim, Youngsoo; Grayson, T Hilton et al. (2012) Transient receptor potential canonical type 3 channels facilitate endothelium-derived hyperpolarization-mediated resistance artery vasodilator activity. Cardiovasc Res 95:439-47
Lloyd, Eric E; Crossland, Randy F; Phillips, Sharon C et al. (2011) Disruption of K(2P)6.1 produces vascular dysfunction and hypertension in mice. Hypertension 58:672-8

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