Department of Animal and Human Biology, University of Turin, via Accademia Albertina 13, I-10123 and NIS Centre of Excellence, Turin, Italy.
Cell Calcium. 2010 Apr;47(4):360-8. doi: 10.1016/j.ceca.2010.01.007. Epub 2010 Feb 19.
Expression of the nerve cell phenotype is orchestrated by the REST/NRSF transcription repressor, working on hundreds of genes recognized at a specific regulatory binding sequence. Most PC12 clones, the most frequently employed neuronal model, maintain low levels of REST; however a few, defective of neurosecretion, express high levels. To investigate the role of REST in Ca2+ signalling we studied the Ca2+ changes in single cells of four clones, two wild-type and two defective, pre-treated for 5 days with NGF. We focused on Ca2+ influxes induced by depolarization and ATP. Only a subpopulation ( approximately 15%) of the defective, high REST cells responded to depolarization (Ca(V) expression approximately 10%). The ATP-induced intracellular Ca2+ release was little changed, whereas influx via ionotropic P2X receptors was decreased, in agreement with the decreased expression of P2X2 receptors. The percentage of defective cells expressing store-operated calcium entry (SOCE) following ATP stimulation was also lower. The responses of the defective clones were little affected by their differentiated state. In conclusion, our results revealed important new aspects of REST control of Ca2+ homeostasis, of potential physiological importance. The mechanisms of this control remain to be investigated.
神经细胞表型的表达是由 REST/NRSF 转录抑制剂协调的，该抑制剂作用于数百个在特定调节结合序列被识别的基因。PC12 克隆是最常用的神经元模型，大多数克隆细胞中 REST 的表达水平较低；然而，有少数缺乏神经分泌的克隆细胞中 REST 的表达水平较高。为了研究 REST 在 Ca2+信号转导中的作用，我们研究了 4 个克隆细胞（2 个野生型和 2 个缺陷型）的单个细胞中的 [Ca2+]i 变化，这些细胞在 NGF 预处理 5 天后。我们专注于由去极化和 ATP 诱导的 Ca2+内流。只有缺陷型细胞的亚群（约 15%）对去极化有反应（CaV 表达约 10%）。ATP 诱导的细胞内 Ca2+释放变化不大，而通过离子型 P2X 受体的内流减少，与 P2X2 受体表达减少一致。在 ATP 刺激后表达 STORE-OPERATED 钙内流（SOCE）的缺陷型细胞的百分比也较低。缺陷型克隆的反应受其分化状态的影响较小。总之，我们的结果揭示了 REST 对 Ca2+稳态的调控的一些重要的新方面，这可能具有潜在的生理重要性。这种调控的机制仍有待研究。
