Mast cells are pluripotent effector cells that reside in tissue. They respond to diverse stimuli by releasing potent biological mediators into the surrounding tissue. These mediators include extracellular proteases, histamine and serotonin, as well numerous cytokines, chemokines, and growth factors. Immunologically, mast cells play a crucial role in the generation and maintenance of inflammation, in response to antigenic challenge. In addition to responses to immunological stimulation, mast cells also respond to polybasic secretagogues and physical stimuli. Through responsiveness to physical stimuli (thermal, osmotic and mechanical inputs), mast cells contribute to both tissue homeostasis, and the wounding process that follows noxious insults. Each mechanism for mast cell activation relies on calcium influx through specific plasma membrane cation channels. Here, we report that calcium-permeant cation channels of the TRPV family are expressed in mast cells. TRPV ion channels are a newly recognized family of sensors, which receive, and react to, physical environmental cues, including thermal, osmotic and mechanical stimuli. The central premise of the current proposal is that TRPV channels transduce physiological, and pathophysiological, signals that are functionally coupled to calcium signaling and mediator release in mast cells. We propose to study the regulation, and function, of TRPV cation channels in the mast cell context. Our first Specific Aim tests the hypothesis that expression of TRPV2 confers a specific, thermally-evoked, cation conductance upon mast cells. In the second Specific Aim, we will explore a novel regulatory mechanism for TRPV2. Our preliminary data show that TRPV2 is a target for phosphorylation by protein kinase A in mast cells, and that this interaction is mediated by a novel adapter protein, PAP7. PAP7 specifically bridges TRPV2 and PKA. We will explore the functional consequences and upstream regulatory mechanisms for phosphorylation of TRPV2 by PKA, and the contribution of PAP7.
In Specific Aim 3, we will examine the representation and functionality of TRPV channels in dermal mast cells, exploring the hypothesis that TRPVs couple mast cell responses to environmental stimuli in the skin.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM070634-04
Application #
7227543
Study Section
Allergy and Immunology Study Section (ALY)
Program Officer
Marino, Pamela
Project Start
2004-05-01
Project End
2009-04-30
Budget Start
2007-05-01
Budget End
2008-04-30
Support Year
4
Fiscal Year
2007
Total Cost
$306,264
Indirect Cost
Name
Queen's Medical Center
Department
Type
DUNS #
054787481
City
Honolulu
State
HI
Country
United States
Zip Code
96813
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Peinelt, Christine; Beck, Andreas; Monteilh-Zoller, Mahealani K et al. (2009) IP(3) receptor subtype-dependent activation of store-operated calcium entry through I(CRAC). Cell Calcium 45:326-30
Lange, Ingo; Penner, Reinhold; Fleig, Andrea et al. (2008) Synergistic regulation of endogenous TRPM2 channels by adenine dinucleotides in primary human neutrophils. Cell Calcium 44:604-15
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Stokes, Alexander J; Wakano, Clay; Del Carmen, Kimberly A et al. (2005) Formation of a physiological complex between TRPV2 and RGA protein promotes cell surface expression of TRPV2. J Cell Biochem 94:669-83