The central focus of this proposal is to define the basic mechanisms of water/fluid transport in the lung and airways in health and disease, and to identify new targets for drug development. Aquaporins (AQPs) are water-transporting proteins expressed in lung microvasculature (AQP1), airways (AQP3 and AQP4), alveolar epithelium (AQP5) and submucosal gland epithelium (AQP5). In the initial award period, mice lacking each of the four major lung aquaporin water channels were generated and used to study the role of aquaporins in fluid transport in alveoli, large airways, and airway submucosal glands. An important finding - AQP5-dependent fluid secretion in airway submucosal glands - will be followed up in Aim 1. Novel aquaporin-selective inhibitors and model systems will be used to test the hypothesis that fluid secretion in human submucosal glands is regulated by AQP5 expression and function.
Aim 2 will critically address the role of aquaporins in other aspects of lung physiology using inhibitors, mouse models, and human tissues. The hypothesis will be tested that lung/airway aquaporins facilitate fluid removal from the airspaces and lung parenchyma following clinically relevant disease/injury.
In Aim 3, novel lung slice, cell culture and fluorescence methods will be used to define water and salt transporting mechanisms in distal airways, an important but under-studied epithelium. The hypothesis that AQP4 and CFTR are required for distal airway fluid absorption will be tested, and the role of the distal airway epithelium is lung fluid clearance will be determined. Together, these experiments will provide definitive information on the role of aquaporins in lung physiology and disease. A unique strength of our research program has been the introduction of new approaches to study lung physiology in vivo and in freshly harvested tissues, and the development of incisive biophysical tools (fluorescent probes, microscopy methods) and inhibitors for water and ion transport studies.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL059198-09
Application #
7245012
Study Section
Lung Biology and Pathology Study Section (LBPA)
Program Officer
Harabin, Andrea L
Project Start
1998-09-01
Project End
2009-07-31
Budget Start
2007-08-01
Budget End
2009-07-31
Support Year
9
Fiscal Year
2007
Total Cost
$323,210
Indirect Cost
Name
University of California San Francisco
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
094878337
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Verkman, A S (2013) Aquaporins. Curr Biol 23:R52-5
Verkman, Alan S; Ratelade, Julien; Rossi, Andrea et al. (2011) Aquaporin-4: orthogonal array assembly, CNS functions, and role in neuromyelitis optica. Acta Pharmacol Sin 32:702-10
Crane, J M; Tajima, M; Verkman, A S (2010) Live-cell imaging of aquaporin-4 diffusion and interactions in orthogonal arrays of particles. Neuroscience 168:892-902
Crane, Jonathan M; Haggie, Peter M; Verkman, A S (2009) QUANTUM DOT SINGLE MOLECULE TRACKING REVEALS A WIDE RANGE OF DIFFUSIVE MOTIONS OF MEMBRANE TRANSPORT PROTEINS. Proc SPIE Int Soc Opt Eng 7489:
Namkung, Wan; Song, Yuanlin; Mills, Aaron D et al. (2009) In situ measurement of airway surface liquid [K+] using a ratioable K+-sensitive fluorescent dye. J Biol Chem 284:15916-26
Verkman, Alan S; Galietta, Luis J V (2009) Chloride channels as drug targets. Nat Rev Drug Discov 8:153-71
Ruiz-Ederra, Javier; Levin, Marc H; Verkman, A S (2009) In situ fluorescence measurement of tear film [Na+], [K+], [Cl-], and pH in mice shows marked hypertonicity in aquaporin-5 deficiency. Invest Ophthalmol Vis Sci 50:2132-8
Yang, Baoxue; Zhao, Dan; Verkman, A S (2009) Hsp90 inhibitor partially corrects nephrogenic diabetes insipidus in a conditional knock-in mouse model of aquaporin-2 mutation. FASEB J 23:503-12
Crane, Jonathan M; Verkman, Alan S (2009) Determinants of aquaporin-4 assembly in orthogonal arrays revealed by live-cell single-molecule fluorescence imaging. J Cell Sci 122:813-21
Tradtrantip, Lukmanee; Sonawane, N D; Namkung, Wan et al. (2009) Nanomolar potency pyrimido-pyrrolo-quinoxalinedione CFTR inhibitor reduces cyst size in a polycystic kidney disease model. J Med Chem 52:6447-55

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