title: Involvement of the Na+/Ca2+ exchanger isoform 1 (NCX1) in neuronal growth factor (NGF)-induced neuronal differentiation through Ca2+-dependent Akt phosphorylation.
abstract: NGF induces neuronal differentiation by modulating [Ca(2+)]i. However, the role of the three isoforms of the main Ca(2+)-extruding system, the Na(+)/Ca(2+) exchanger (NCX), in NGF-induced differentiation remains unexplored. We investigated whether NCX1, NCX2, and NCX3 isoforms could play a relevant role in neuronal differentiation through the modulation of [Ca(2+)]i and the Akt pathway. NGF caused progressive neurite elongation; a significant increase of the well known marker of growth cones, GAP-43; and an enhancement of endoplasmic reticulum (ER) Ca(2+) content and of Akt phosphorylation through an early activation of ERK1/2. Interestingly, during NGF-induced differentiation, the NCX1 protein level increased, NCX3 decreased, and NCX2 remained unaffected. At the same time, NCX total activity increased. Moreover, NCX1 colocalized and coimmunoprecipitated with GAP-43, and NCX1 silencing prevented NGF-induced effects on GAP-43 expression, Akt phosphorylation, and neurite outgrowth. On the other hand, the overexpression of its neuronal splicing isoform, NCX1.4, even in the absence of NGF, induced an increase in Akt phosphorylation and GAP-43 protein expression. Interestingly, tetrodotoxin-sensitive Na(+) currents and 1,3-benzenedicarboxylic acid, 4,4'-[1,4,10-trioxa-7,13-diazacyclopentadecane-7,13-diylbis(5-methoxy-6,12-benzofurandiyl)]bis-, tetrakis[(acetyloxy)methyl] ester-detected [Na(+)]i significantly increased in cells overexpressing NCX1.4 as well as ER Ca(2+) content. This latter effect was prevented by tetrodotoxin. Furthermore, either the [Ca(2+)]i chelator(1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid) (BAPTA-AM) or the PI3K inhibitor LY 294002 prevented Akt phosphorylation and GAP-43 protein expression rise in NCX1.4 overexpressing cells. Moreover, in primary cortical neurons, NCX1 silencing prevented Akt phosphorylation, GAP-43 and MAP2 overexpression, and neurite elongation. Collectively, these data show that NCX1 participates in neuronal differentiation through the modulation of ER Ca(2+) content and PI3K signaling.
authors.affiliation: From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and.
authors.forename: Agnese
authors.initials: A
authors.lastname: Secondo
authors.affiliation: From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and.
authors.forename: Alba
authors.initials: A
authors.lastname: Esposito
authors.affiliation: the Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) SDN, Naples 80143, Italy.
authors.forename: Rossana
authors.initials: R
authors.lastname: Sirabella
authors.affiliation: From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and.
authors.forename: Francesca
authors.initials: F
authors.lastname: Boscia
authors.affiliation: From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and.
authors.forename: Anna
authors.initials: A
authors.lastname: Pannaccione
authors.affiliation: From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Molinaro
authors.affiliation: From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and.
authors.forename: Maria
authors.initials: M
authors.lastname: Cantile
authors.affiliation: From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and.
authors.forename: Roselia
authors.initials: R
authors.lastname: Ciccone
authors.affiliation: From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and.
authors.forename: Maria Josè
authors.initials: MJ
authors.lastname: Sisalli
authors.affiliation: From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and.
authors.forename: Antonella
authors.initials: A
authors.lastname: Scorziello
authors.affiliation: From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Di Renzo
authors.affiliation: From the Department of Neuroscience and Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Via Sergio Pansini 5, Naples 80131, Italy and the Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) SDN, Naples 80143, Italy lannunzi@unina.it.
authors.forename: Lucio
authors.initials: L
authors.lastname: Annunziato
mesh_terms: D000818:Animals; D001921:Brain / Q000196:embryology*; D002118:Calcium / Q000378:metabolism*; D002454:Cell Differentiation; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004789:Enzyme Activation; D006706:Homeostasis; D009154:Mutation; D020932:Nerve Growth Factor / Q000494:pharmacology*; D016501:Neurites / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000378:metabolism*; D016716:PC12 Cells; D018408:Patch-Clamp Techniques; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D012964:Sodium / Q000378:metabolism; D019831:Sodium-Calcium Exchanger / Q000378:metabolism*
chemical_list: D034741:RNA, Small Interfering; D019831:Sodium-Calcium Exchanger; C110374:sodium-calcium exchanger 1; D020932:Nerve Growth Factor; D012964:Sodium; D019869:Phosphatidylinositol 3-Kinases; D002118:Calcium
keywords: Akt; Calcium Imaging; Calcium Transport; Neurite Outgrowth; PI3K