The activity of BK (slol) channels in brain artery myocytes and neurons is modified by acute exposure to ethanol (EtOH) levels reached in blood during alcohol intoxication, such modification contributing to EtOH perturbation of physiology. EtOH actions in the body may require drug-mediated potentiation or inhibition of BK channels. Our long-term goal is to identify molecular mechanisms and protein sites that lead to BK channel differential responses to EtOH and their contribution to drug actions on the brain. This knowledge is essential towards identification of brain vulnerability and design of therapeutic interventions in alcohol-driven pathology via BK channel-targeting. In particular, EtOH inhibition of cerebral artery myocyte BK current is the key event in alcohol-mediated cerebral artery constriction, an alcohol action that is independent of circulating and endothelial factors, and likely contributes to alcohol-induced cerebrovascular disease and accidents. The myocyte-abundant BK pi subunit (coded by KNCMB1) facilitates slol (coded by KCNMA1) channel inhibition by EtOH and coupling to type2 ryanodine receptors (RyR2), these proteins constituting a triad that controls cerebral artery tone and is directly targeted by EtOH.
Aim1 addresses the role of BK p i membrane levels in EtOH vulnerability of brain arteries that irrigate distinct CNS regions and are differentially subject to cerebrovascular events.
The aim i s tested in rodent models (rat, KCNMB1 K/0 mouse) using both in vitro (Western-blotting, protein biotinylation, ICC/IF microscopy, patch-clamp, cDNA reverse-permeabilization, and isolated myocytes and arteries) and in vivo methods (closed cranial window, intravital microscopy). Defined by similar models and methods, and supplemented by computational modeling and medicinal chemistry, Aim2 determines whether BK pi-targeting by novel agents antagonizes cerebral artery constriction caused by EtOH. Putative EtOH-sensing sites and regions in the three proteins that constitute the EtOH target: BK pi (SubAim 3.1), slol (SubAim 3.2) and RyR2 (Aim 4) are identified via computational modeling, mutagenesis and in vitro electrophysiology, the impact of these sites on physiology being established by reverse-permeabilization of relevant rodent artery (KCNMB1 K/O, KCNMA1 K/O mice).

Public Health Relevance

Cerebral artery constriction is often a main component of brain conditions and accidents associated with ethanol intoxication. We will identify the ethanol-recognition sites in the ion channels that mediate ethanol-induced cerebral artery constriction and use this information to point at vulnerability and therapeutics to counteract cerebrovascular pathophysiology caused by ethanol intake.

Agency
National Institute of Health (NIH)
Institute
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37AA011560-18
Application #
8871622
Study Section
Special Emphasis Panel (NSS)
Program Officer
Orosz, Andras
Project Start
1999-01-01
Project End
2019-06-30
Budget Start
2015-07-01
Budget End
2016-06-30
Support Year
18
Fiscal Year
2015
Total Cost
Indirect Cost
Name
University of Tennessee Health Science Center
Department
Pharmacology
Type
Schools of Medicine
DUNS #
941884009
City
Memphis
State
TN
Country
United States
Zip Code
38103
North, Kelsey; Bisen, Shivantika; Dopico, Alex M et al. (2018) Tyrosine 450 in the Voltage- and Calcium-Gated Potassium Channel of Large Conductance Channel Pore-Forming (slo1) Subunit Mediates Cholesterol Protection against Alcohol-Induced Constriction of Cerebral Arteries. J Pharmacol Exp Ther 367:234-244
Bukiya, Anna N; Dopico, Alex M (2018) Fetal Cerebral Circulation as Target of Maternal Alcohol Consumption. Alcohol Clin Exp Res 42:1006-1018
Kuntamallappanavar, Guruprasad; Bisen, Shivantika; Bukiya, Anna N et al. (2017) Differential distribution and functional impact of BK channel beta1 subunits across mesenteric, coronary, and different cerebral arteries of the rat. Pflugers Arch 469:263-277
Simakova, Maria N; Bisen, Shivantika; Dopico, Alex M et al. (2017) Statin therapy exacerbates alcohol-induced constriction of cerebral arteries via modulation of ethanol-induced BK channel inhibition in vascular smooth muscle. Biochem Pharmacol 145:81-93
Dopico, A M; Bukiya, A N; Kuntamallappanavar, G et al. (2016) Modulation of BK Channels by Ethanol. Int Rev Neurobiol 128:239-79
Bisen, Shivantika; Seleverstov, Olga; Belani, Jitendra et al. (2016) Distinct mechanisms underlying cholesterol protection against alcohol-induced BK channel inhibition and resulting vasoconstriction. Biochim Biophys Acta 1861:1756-1766
Kuntamallappanavar, Guruprasad; Dopico, Alex M (2016) Alcohol modulation of BK channel gating depends on ? subunit composition. J Gen Physiol 148:419-440
Chang, Jennifer; Fedinec, Alexander L; Kuntamallappanavar, Guruprasad et al. (2016) Endothelial Nitric Oxide Mediates Caffeine Antagonism of Alcohol-Induced Cerebral Artery Constriction. J Pharmacol Exp Ther 356:106-15
Tan, Xing-Lin; Xue, Yue-Qiang; Ma, Tao et al. (2015) Partial eNOS deficiency causes spontaneous thrombotic cerebral infarction, amyloid angiopathy and cognitive impairment. Mol Neurodegener 10:24
Bukiya, Anna N; McMillan, Jacob; Liu, Jianxi et al. (2014) Activation of calcium- and voltage-gated potassium channels of large conductance by leukotriene B4. J Biol Chem 289:35314-25

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