TY - JOUR
T1 - NCX1 expression and functional activity increase in microglia invading the infarct core
AU - Boscia, Francesca
AU - Gala, Rosaria
AU - Pannaccione, Anna
AU - Secondo, Agnese
AU - Scorziello, Antonella
AU - Di Renzo, Gianfranco
AU - Annunziato, Lucio
PY - 2009/11
Y1 - 2009/11
N2 - BACKGROUND AND PURPOSE-: The sodium-calcium exchanger NCX1 represents a key mediator for maintaining [Na]i and [Ca]i in anoxic conditions. To date, no information is available on NCX1 protein expression and activity in microglial cells under ischemic conditions. METHODS-: By means of Western blotting, patch-clamp electrophysiology, single-cell Fura-2 acetoxymethyl-ester microfluorometry, immunohistochemistry, and confocal microscopy, we investigated the regional and temporal changes of NCX1 protein in microglial cells of the peri-infarct and core regions after permanent middle cerebral artery occlusion. The exchanger expression and activity were measured in primary microglia isolated ex vivo from the core region of adult rat brains 7 days after permanent middle cerebral artery occlusion and in cultured microglia under in vitro hypoxia. RESULTS-: One day after permanent middle cerebral artery occlusion, NCX1 protein expression was detected in some microglial cells adjacent to the soma of neurons in the infarct core. More interestingly, 3 and 7 days after permanent middle cerebral artery occlusion, NCX1 signal strongly increased in the round-shaped microglia invading the infarct core. Cultured microglial cells obtained from the core also displayed increased NCX1 expression as compared with contralateral cells and showed enhanced NCX activity in the reverse mode of operation. Similarly, NCX activity and NCX1 protein expression were significantly enhanced in BV2 microglia exposed to oxygen and glucose deprivation, whereas NCX2 and NCX3 were downregulated. Interestingly, in NCX1-silenced cells, [Ca]i increase induced by hypoxia was completely prevented.
AB - BACKGROUND AND PURPOSE-: The sodium-calcium exchanger NCX1 represents a key mediator for maintaining [Na]i and [Ca]i in anoxic conditions. To date, no information is available on NCX1 protein expression and activity in microglial cells under ischemic conditions. METHODS-: By means of Western blotting, patch-clamp electrophysiology, single-cell Fura-2 acetoxymethyl-ester microfluorometry, immunohistochemistry, and confocal microscopy, we investigated the regional and temporal changes of NCX1 protein in microglial cells of the peri-infarct and core regions after permanent middle cerebral artery occlusion. The exchanger expression and activity were measured in primary microglia isolated ex vivo from the core region of adult rat brains 7 days after permanent middle cerebral artery occlusion and in cultured microglia under in vitro hypoxia. RESULTS-: One day after permanent middle cerebral artery occlusion, NCX1 protein expression was detected in some microglial cells adjacent to the soma of neurons in the infarct core. More interestingly, 3 and 7 days after permanent middle cerebral artery occlusion, NCX1 signal strongly increased in the round-shaped microglia invading the infarct core. Cultured microglial cells obtained from the core also displayed increased NCX1 expression as compared with contralateral cells and showed enhanced NCX activity in the reverse mode of operation. Similarly, NCX activity and NCX1 protein expression were significantly enhanced in BV2 microglia exposed to oxygen and glucose deprivation, whereas NCX2 and NCX3 were downregulated. Interestingly, in NCX1-silenced cells, [Ca]i increase induced by hypoxia was completely prevented.
KW - Cerebral ischemia
KW - IB4
KW - Microglia
KW - Na/Ca2 exchanger
KW - NCX1
KW - PMCAO
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U2 - 10.1161/STROKEAHA.109.557439
DO - 10.1161/STROKEAHA.109.557439
M3 - Article
C2 - 19745171
AN - SCOPUS:70350550320
VL - 40
SP - 3608
EP - 3617
JO - Stroke
JF - Stroke
SN - 0039-2499
IS - 11
ER -