The Transient Receptor Potential Vanilloid 1 channel (TRPV1) is a key component of nociceptors and is also a mechanosensor in the urinary bladder and osmosensor in neurons. The water channel Aquaporin-4 (AQP-4) is found in glial cells in the CNS and is critical for water homeostasis in the brain. Although both TRPV1 and AQP-4 are important in normal body function and several pathological conditions, little is currently known about how the functions of these channels are modified by bilayer composition or their membrane microdomain locations. These are fundamental issues because the functions of many ion channels have been shown to be modified by specific membrane lipids such as phosphatidylinositol-4,5 bisphosphate (PIP2), as well as by membrane material properties controlled by the presence of cholesterol. Moreover, some channels are sequestered into cholesterol-rich plasma membrane microdomains called rafts. This application uses patch clamp electrophysiology and micropipette aspiration to measure the role of bilayer cholesterol concentration on the channel properties of TRPV1 and AQP-4, respectively. In addition, a variety of techniques, including confocal microscopy and freeze-fracture electron microscopy, will be employed to determine the microdomain locations of TRPV1 and AQP-4 and test possible mechanisms for the sequestering of channels into rafts. Our hypotheses are that: (1) specific protein-lipid and protein- protein interactions, including homo-oligomerization of the channels, are key factors in sorting channels between microdomains, (2) bilayer material properties (as controlled by phospholipid hydrocarbon chain composition and cholesterol content) modulate the function of both TRPV1 and AQP-4, and (3) acylated polybasic cytoplasmic proteins can sequester key regulatory lipids such as PIP2 into raft domains in the cytoplasmic leaflet of membrane bilayers.

Public Health Relevance

The water channel AQP-4 and the Transient Receptor Potential channel TRPV1 are critically important in normal body function and several pathological conditions. AQP-4, expressed in glial cells in the brain, is implicated in brain edema and a variety of cerebral disorders. TRPV1, found in many regions of the body including pain receptors, is implicated in bowel disease, contact dermatitis, as well as pain in general.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM027278-30
Application #
8134970
Study Section
Biochemistry and Biophysics of Membranes Study Section (BBM)
Program Officer
Chin, Jean
Project Start
1980-07-01
Project End
2013-08-31
Budget Start
2011-09-01
Budget End
2012-08-31
Support Year
30
Fiscal Year
2011
Total Cost
$366,949
Indirect Cost
Name
Duke University
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
McIntosh, Thomas J (2015) Stepping between membrane microdomains. Biophys J 108:783-784
Tong, Jihong; Canty, John T; Briggs, Margaret M et al. (2013) The water permeability of lens aquaporin-0 depends on its lipid bilayer environment. Exp Eye Res 113:32-40
Zhang, Xiao-Xiang; McIntosh, Thomas J; Grinstaff, Mark W (2012) Functional lipids and lipoplexes for improved gene delivery. Biochimie 94:42-58
Godeau, Guilhem; Navailles, Laurence; Nallet, Frédéric et al. (2012) From Brittle to Pliant Viscoelastic Materials with Solid State Linear Polyphosphonium - Carboxylate Assemblies. Macromolecules 45:2509-2513
Tong, Jihong; Briggs, Margaret M; McIntosh, Thomas J (2012) Water permeability of aquaporin-4 channel depends on bilayer composition, thickness, and elasticity. Biophys J 103:1899-908
LaManna, Caroline M; Lusic, Hrvoje; Camplo, Michel et al. (2012) Charge-reversal lipids, peptide-based lipids, and nucleoside-based lipids for gene delivery. Acc Chem Res 45:1026-38
Picazo-Juárez, Giovanni; Romero-Suárez, Silvina; Nieto-Posadas, Andrés et al. (2011) Identification of a binding motif in the S5 helix that confers cholesterol sensitivity to the TRPV1 ion channel. J Biol Chem 286:24966-76
Zhang, Xiao-Xiang; Prata, Carla A H; Berlin, Jason A et al. (2011) Synthesis, characterization, and in vitro transfection activity of charge-reversal amphiphiles for DNA delivery. Bioconjug Chem 22:690-9
Zhang, Xiao-Xiang; Prata, Carla A H; McIntosh, Thomas J et al. (2010) The effect of charge-reversal amphiphile spacer composition on DNA and siRNA delivery. Bioconjug Chem 21:988-93
Rosenbaum, Tamara; Simon, Sidney A; Islas, Leon D (2010) Ion channels in analgesia research. Methods Mol Biol 617:223-36

Showing the most recent 10 out of 94 publications