title: NCX1 expression and functional activity increase in microglia invading the infarct core.
abstract: OBJECTIVE
  The sodium-calcium exchanger NCX1 represents a key mediator for maintaining [Na(+)](i) and [Ca(2+)](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(2+)](i) increase induced by hypoxia was completely prevented. Conclusion- The upregulation of NCX1 expression and activity observed in microglia after permanent middle cerebral artery occlusion suggests a relevant role of NCX1 in modulating microglia functions in the postischemic brain.
authors.affiliation: Division of Pharmacology, Department of Neuroscience, School of Medicine, Federico II, University of Naples, Naples, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Boscia
authors.forename: Rosaria
authors.initials: R
authors.lastname: Gala
authors.forename: Anna
authors.initials: A
authors.lastname: Pannaccione
authors.forename: Agnese
authors.initials: A
authors.lastname: Secondo
authors.forename: Antonella
authors.initials: A
authors.lastname: Scorziello
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Di Renzo
authors.forename: Lucio
authors.initials: L
authors.lastname: Annunziato
mesh_terms: D000818:Animals; D002465:Cell Movement / Q000235:genetics* / Q000502:physiology; D002478:Cells, Cultured; D002544:Cerebral Infarction / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D005786:Gene Expression Regulation / Q000502:physiology*; D008297:Male; D017628:Microglia / Q000473:pathology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019831:Sodium-Calcium Exchanger / Q000096:biosynthesis* / Q000235:genetics* / Q000502:physiology; D015854:Up-Regulation / Q000235:genetics* / Q000502:physiology
chemical_list: D019831:Sodium-Calcium Exchanger; C110374:sodium-calcium exchanger 1