title: Functional decreases in P2X7 receptors are associated with retinoic acid-induced  neuronal differentiation of Neuro-2a neuroblastoma cells.
abstract: Neuro-2a (N2a) cells are derived from spontaneous neuroblastoma of mouse and capable to differentiate into neuronal-like cells. Recently, P2X7 receptor has been shown to sustain growth of human neuroblastoma cells but its role during neuronal differentiation remains unexamined.We characterized the role of P2X7 receptors in the retinoic acid (RA)-differentiated N2a cells. RA induced N2a cells differentiation into neurite bearing and neuronal specific proteins, microtubule-associated protein 2 (MAP2) and neuronal specific nuclear protein (NeuN), expressing neuronal-like cells. Interestingly, the RA-induced neuronal differentiation was associated with decreases in the expression and function of P2X7 receptors. Functional inhibition of P2X7 receptors by P2X7 receptor selective antagonists, 5'-triphosphate, periodate-oxidized 2',3'-dialdehyde ATP (oATP), brilliant blue G (BBG) or A438079 induced neurite outgrowth. In addition, RA and oATP treatment stimulated the expression of neuron-specific class III beta-tubulin (TuJ1), and knockdown of P2X7 receptor expression by siRNA induced neurite outgrowth. To elucidate the possible mechanism, we found the levels of basal intracellular Ca2+ concentrations ([Ca2+]i) were decreased in either RA- or oATP-differentiated or P2X7receptor knockdown N2a cells. Simply cultured N2a cells in low Ca2+ medium induced a 2-fold increase in neurite length. Treatment of N2a cells with ATP hydrolase apyrase and the P2X7 receptors selective antagonist oATP or BBG decreased cell viability and cell number. Nevertheless, oATP but not BBG decreased cell proliferation and cell cycle progression. These results suggest for the first time that decreases in expression/function of P2X7 receptors are involved in neuronal differentiation.We provide additional evidence shown that the ATP release-activated P2X7 receptor is important in maintaining cell survival of N2a neuroblastoma cells.
authors.affiliation: Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan, ROC.
authors.forename: Pei-Yu
authors.initials: PY
authors.lastname: Wu
authors.forename: Yu-Chia
authors.initials: YC
authors.lastname: Lin
authors.forename: Chia-Ling
authors.initials: CL
authors.lastname: Chang
authors.forename: Hsing-Tsen
authors.initials: HT
authors.lastname: Lu
authors.forename: Chia-Hsuan
authors.initials: CH
authors.lastname: Chin
authors.forename: Tsan-Ting
authors.initials: TT
authors.lastname: Hsu
authors.forename: Dachen
authors.initials: D
authors.lastname: Chu
authors.forename: Synthia H
authors.initials: SH
authors.lastname: Sun
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D055785:Gene Knockdown Techniques; D051379:Mice; D016501:Neurites / Q000187:drug effects / Q000378:metabolism; D009447:Neuroblastoma / Q000378:metabolism* / Q000473:pathology*; D009474:Neurons / Q000166:cytology* / Q000187:drug effects*; D058919:Purinergic P2 Receptor Antagonists; D034741:RNA, Small Interfering / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058486:Receptors, Purinergic P2X7; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: C546468:P2RX7 protein, human; C546469:P2rx7 protein, mouse; D058919:Purinergic P2 Receptor Antagonists; D034741:RNA, Small Interfering; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; C017199:2',3'-dialdehyde ATP; D014212:Tretinoin; D000255:Adenosine Triphosphate