RT Journal Article
SR Electronic
T1 Contribution of Pannexin 1 and Connexin 43 Hemichannels to Extracellular Calcium–Dependent Transport Dynamics in Human Blood-Brain Barrier Endothelial Cells
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 192
OP 200
DO 10.1124/jpet.114.220210
VO 353
IS 1
A1 Yosuke Kaneko
A1 Masanori Tachikawa
A1 Ryo Akaogi
A1 Kazuhisa Fujimoto
A1 Megumi Ishibashi
A1 Yasuo Uchida
A1 Pierre-Olivier Couraud
A1 Sumio Ohtsuki
A1 Ken-ichi Hosoya
A1 Tetsuya Terasaki
YR 2015
UL http://jpet.aspetjournals.org/content/353/1/192.abstract
AB Dysregulation of blood-brain barrier (BBB) transport function is thought to exacerbate neuronal damage in acute ischemic stroke. The purpose of this study was to clarify the characteristics of pannexin (Px) and/or connexin (Cx) hemichannel(s)-mediated transport of organic anions and cations in human BBB endothelial cell line hCMEC/D3 and to identify inhibitors of hemichannel opening in hCMEC/D3 cells in the absence of extracellular Ca2+, a condition mimicking acute ischemic stroke. In the absence of extracellular Ca2+, the cells showed increased uptake and efflux transport of organic ionic fluorescent dyes. Classic hemichannel inhibitors markedly inhibited the enhanced uptake and efflux. Quantitative targeted absolute proteomics confirmed Px1 and Cx43 protein expression in plasma membrane of hCMEC/D3 cells. Knockdown of Px1 and Cx43 with the small interfering RNAs significantly inhibited the enhanced uptake and efflux of organic anionic and cationic fluorescent dyes. Clinically used cilnidipine and progesterone, which have neuroprotective effects in animal ischemia models, were identified as inhibitors of hemichannel opening. These findings suggest that altered transport dynamics at the human BBB in the absence of extracellular Ca2+ is at least partly attributable to opening of Px1 and Cx43 hemichannels. Therefore, we speculate that Px1 and Cx43 may be potential drug targets to ameliorate BBB transport dysregulation during acute ischemia.