Cerebral circulation is exquisitely regulated, but mechanisms involved still require considerable investigation. Cerebral arteries are major resistance vessels critical for control of brain regional blood flow. Cerebral artery smooth muscle cell membrane potential controls intracellular calcium ([Ca2+]i) concentration and is a major regulator of contractility. Although several cation channels that regulate arterial smooth muscle cell membrane potential have been identified, vasoregulation by anion channels is poorly understood. In particular, the molecular identity and physiological functions of arterial smooth muscle cell chloride (Cl-) channels is unclear. Hypertension is associated with increased risk for devastating cerebral diseases, including stroke and dementia. Cerebral arteries from hypertensive subjects are depolarized, leading to elevated contractility, but involvement of Cl- channels in this pathological alteration is not known. This application derives from novel preliminary data suggesting that recently discovered transmembrane 16A Cl- (TMEM16A) channels are expressed in cerebral artery smooth muscle cells and regulate arterial contractility. We also provide novel data indicating that hypertension is associated with alterations in TMEM16A channels that elevate cerebral artery contractility.
Three specific aims will be investigated to test the central hypothesis that cerebral artery smooth muscle cell TMEM16A channels control physiological arterial contractility and alterations in TMEM16A channel regulation elevate contractility in hypertension.
Aim 1 will examine the molecular identity and regulation of TMEM16 channels expressed in arterial smooth muscle cells.
Aim 2 will elucidate the functional significance of smooth muscle cell TMEM16A channels in controlling arterial membrane potential, [Ca2+]i and contractility.
Aim 3 will explore the hypothesis that systemic hypertension is associated with an alteration in smooth muscle cell TMEM16A channels and that inhibiting myocyte TMEM16A channels in hypertension induces vasodilation. This proposal will provide significant novel information concerning cerebral artery regulation by smooth muscle cell Cl- channels and will evaluate the potential that TMEM16A channels are a new molecular target for modulating contractility.
Arterial smooth muscle cell ion channels modulate regional blood flow in the brain, but the molecular identity of anion channels, particularly chloride channels, in smooth muscle cells is poorly understood. Pathological alterations in cerebral artery smooth muscle cell ion channels are associated with vascular diseases, including stroke and dementia, but whether chloride channels are involved is unclear. Our proposal will investigate the novel hypothesis that recently discovered TMEM16A chloride channels are expressed in cerebral artery smooth muscle cells where they regulate physiological arterial contraction, and pathological alterations in these channels elevates cerebral artery contractility in hypertension.
|Zhai, Xue; Leo, M Dennis; Jaggar, Jonathan H (2017) Endothelin-1 Stimulates Vasoconstriction Through Rab11A Serine 177 Phosphorylation. Circ Res 121:650-661|
|Leo, M Dennis; Zhai, Xue; Muralidharan, Padmapriya et al. (2017) Membrane depolarization activates BK channels through ROCK-mediated ?1 subunit surface trafficking to limit vasoconstriction. Sci Signal 10:|
|Kidd, Michael W; Bulley, Simon; Jaggar, Jonathan H (2017) Angiotensin II reduces the surface abundance of KV 1.5 channels in arterial myocytes to stimulate vasoconstriction. J Physiol 595:1607-1618|
|Bannister, John P; Bulley, Simon; Leo, M Dennis et al. (2016) Rab25 influences functional Cav1.2 channel surface expression in arterial smooth muscle cells. Am J Physiol Cell Physiol 310:C885-93|
|Wang, Qian; Leo, M Dennis; Narayanan, Damodaran et al. (2016) Local coupling of TRPC6 to ANO1/TMEM16A channels in smooth muscle cells amplifies vasoconstriction in cerebral arteries. Am J Physiol Cell Physiol 310:C1001-9|
|Samak, Geetha; Chaudhry, Kamaljit K; Gangwar, Ruchika et al. (2015) Calcium/Ask1/MKK7/JNK2/c-Src signalling cascade mediates disruption of intestinal epithelial tight junctions by dextran sulfate sodium. Biochem J 465:503-15|
|Peixoto-Neves, Dieniffer; Wang, Qian; Leal-Cardoso, Jose H et al. (2015) Eugenol dilates mesenteric arteries and reduces systemic BP by activating endothelial cell TRPV4 channels. Br J Pharmacol 172:3484-94|
|Sullivan, Michelle N; Gonzales, Albert L; Pires, Paulo W et al. (2015) Localized TRPA1 channel Ca2+ signals stimulated by reactive oxygen species promote cerebral artery dilation. Sci Signal 8:ra2|
|Leo, M Dennis; Bulley, Simon; Bannister, John P et al. (2015) Angiotensin II stimulates internalization and degradation of arterial myocyte plasma membrane BK channels to induce vasoconstriction. Am J Physiol Cell Physiol 309:C392-402|
|Burris, Sarah K; Wang, Qian; Bulley, Simon et al. (2015) 9-Phenanthrol inhibits recombinant and arterial myocyte TMEM16A channels. Br J Pharmacol 172:2459-68|
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