Deficiencies in Na+/H+ or CI-/HCO3- exchange compromise fluid and electrolyte transport in the mammalian intestine, but the ultimate role of acid-base transport in nutrient uptake processes and lipid metabolism is relatively poorly understood. In addition, little is known regarding how intestinal pHi influences cell signaling events that response to nutrient availability. We hypothesis that pHi acts as a synergistic messenger, and provides a metabolic context through which the actions of diverse cellular and trans-cellular signaling pathways are interpreted. In this application, we offer preliminary evidence linking acid-base transport to fat storage and related signaling events in the nematode C. elegans, and propose the following:
Aim 1 involves characterizing the SLC4 and SLC26 CI-/HCO3- homologs in C. elegans by first assessing their distribution, then examining function both in situ, using recombinant protein expression and in vivo, using a genetically encoded pH indicator and RNAi.
Aim 2 is designed to test how changes in intestinal pHi affect classic cell signaling processes that regulate fat storage, and conversely what cell signaling processes are involved in conveying the phenotypic effects of cellular acidosis.
Aim 3 is designed to utilize genetic, reverse-genetic, and functional genomic assays to identify regulatory proteins that attenuate intracellular pH, as well as the global transcriptional responses to intracellular acidification. The strength of this proposal is that it will use a powerful model system and novel reagents for monitoring pH in living organisms to study fat biology from a unique perspective: that of acid-base homeostasis.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL080810-04
Application #
7278611
Study Section
Special Emphasis Panel (ZDK1-GRB-2 (O2))
Program Officer
Srinivas, Pothur R
Project Start
2004-09-27
Project End
2009-07-31
Budget Start
2007-08-01
Budget End
2009-07-31
Support Year
4
Fiscal Year
2007
Total Cost
$295,832
Indirect Cost
Name
University of Rochester
Department
Dentistry
Type
Schools of Dentistry
DUNS #
041294109
City
Rochester
State
NY
Country
United States
Zip Code
14627
Johnson, David; Nehrke, Keith (2010) Mitochondrial fragmentation leads to intracellular acidification in Caenorhabditis elegans and mammalian cells. Mol Biol Cell 21:2191-201
Allman, Erik; Johnson, David; Nehrke, Keith (2009) Loss of the apical V-ATPase a-subunit VHA-6 prevents acidification of the intestinal lumen during a rhythmic behavior in C. elegans. Am J Physiol Cell Physiol 297:C1071-81
Nehrke, K; Denton, Jerod; Mowrey, William (2008) Intestinal Ca2+ wave dynamics in freely moving C. elegans coordinate execution of a rhythmic motor program. Am J Physiol Cell Physiol 294:C333-44
Pfeiffer, Jason; Johnson, David; Nehrke, Keith (2008) Oscillatory transepithelial H(+) flux regulates a rhythmic behavior in C. elegans. Curr Biol 18:297-302
Wojtovich, Andrew P; Burwell, Lindsay S; Sherman, Teresa A et al. (2008) The C. elegans mitochondrial K+(ATP) channel: a potential target for preconditioning. Biochem Biophys Res Commun 376:625-8
He, Liping; Denton, Jerod; Nehrke, Keith et al. (2006) Carboxy terminus splice variation alters ClC channel gating and extracellular cysteine reactivity. Biophys J 90:3570-81
Denton, Jerod; Nehrke, Keith; Yin, Xiaoyan et al. (2005) GCK-3, a newly identified Ste20 kinase, binds to and regulates the activity of a cell cycle-dependent ClC anion channel. J Gen Physiol 125:113-25
de Santiago, Jose Antonio; Nehrke, Keith; Arreola, Jorge (2005) Quantitative analysis of the voltage-dependent gating of mouse parotid ClC-2 chloride channel. J Gen Physiol 126:591-603