The long term objective of my lab is to understand the molecular basis of mechanotransduction. This includes the 1) identification of components of mechanosensitive ion channel complexes in sensory neurons and vascular smooth muscle cells, 2) regulation of mechanosensitive ion channel expression by physical and hormonal factors and 3) involvement in cardiovascular pathophysiology (hypertension, autonomic dysfunction). The current proposal will address a highly novel area of research: role of ENaC proteins as mechanosensors in vascular smooth muscle. Hypertension induced renal injury has multiple causes including hormonal and autocrine factors and pressure. Pressure-induced, or myogenic, constriction of renal vessels protects the kidney from pressure related injury. The molecular mechanism underlying mechanotransduction of the pressure stimulus is unknown. The hypothesis underlying this proposal is that beta and/or gamma ENaC proteins are components of mechanosensitive ion channel complexes in vascular smooth muscle cells. Pressure induced vascular tension activates mechanosensitive channels containing beta and gamma ENaC leading to sodium and calcium influx and myogenic constriction. Since myogenic constriction protects the kidney from end-organ damage, we further hypothesize that loss of beta ENaC expression will prevent myogenic constriction and predispose the kidney to pressure induced injury. The goals of this proposal are to determine if beta ENaC protein is required for 1) myogenic constriction, and 2) pressure activated sodium and calcium ion transients, 3) renal autoregulation, and 4) renal protection from pressure induced injury, renal interlobar artery segments. To assess the importance of beta ENaC in these responses, we have developed a double transgenic mouse model where beta ENaC is silenced in a tissue- and time-selective manner. Results from this proposal will help define the molecular mechanism of myogenic constriction and provide a better understanding of pressure induced end organ damage. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL086996-02
Application #
7463616
Study Section
Hypertension and Microcirculation Study Section (HM)
Program Officer
Goldman, Stephen
Project Start
2007-07-06
Project End
2011-05-31
Budget Start
2008-06-01
Budget End
2009-05-31
Support Year
2
Fiscal Year
2008
Total Cost
$370,000
Indirect Cost
Name
University of Mississippi Medical Center
Department
Physiology
Type
Schools of Medicine
DUNS #
928824473
City
Jackson
State
MS
Country
United States
Zip Code
39216
Drummond, Heather A; Stec, David E (2015) ?ENaC acts as a mechanosensor in renal vascular smooth muscle cells that contributes to renal myogenic blood flow regulation, protection from renal injury and hypertension. J Nephrol Res 1:1-9
Chung, Wen-Shuo; Weissman, Jennifer L; Farley, Jerry et al. (2013) ?ENaC is required for whole cell mechanically gated currents in renal vascular smooth muscle cells. Am J Physiol Renal Physiol 304:F1428-37
Ge, Ying; Gannon, Kimberly; Gousset, Monette et al. (2012) Impaired myogenic constriction of the renal afferent arteriole in a mouse model of reduced ?ENaC expression. Am J Physiol Renal Physiol 302:F1486-93
Ryan, Michael J; Gilbert, Emily L; Glover, Porter H et al. (2011) Placental ischemia impairs middle cerebral artery myogenic responses in the pregnant rat. Hypertension 58:1126-31
Chung, Wen-Shuo; Farley, Jerry M; Drummond, Heather A (2011) ASIC-like currents in freshly isolated cerebral artery smooth muscle cells are inhibited by endogenous oxidase activity. Cell Physiol Biochem 27:129-38
Drummond, Heather A; Grifoni, Samira C; Abu-Zaid, Ahmed et al. (2011) Renal inflammation and elevated blood pressure in a mouse model of reduced {beta}-ENaC. Am J Physiol Renal Physiol 301:F443-9
Chung, Wen-Shuo; Farley, Jerry M; Swenson, Alyssa et al. (2010) Extracellular acidosis activates ASIC-like channels in freshly isolated cerebral artery smooth muscle cells. Am J Physiol Cell Physiol 298:C1198-208
Grifoni, Samira C; Chiposi, Rumbidzayi; McKey, Susan E et al. (2010) Altered whole kidney blood flow autoregulation in a mouse model of reduced beta-ENaC. Am J Physiol Renal Physiol 298:F285-92
Venegas-Pont, Marcia; Manigrasso, Michaele B; Grifoni, Samira C et al. (2010) Tumor necrosis factor-alpha antagonist etanercept decreases blood pressure and protects the kidney in a mouse model of systemic lupus erythematosus. Hypertension 56:643-9
Drummond, Heather (2010) Response to Role of Epithelial Sodium Channels in the Renal Myogenic Response? Hypertension 55:e7

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