Homer1 knockdown protects dopamine neurons through regulating calcium homeostasis in an in vitro model of Parkinson's disease
Homer1 knockdown protects dopamine neurons through regulating calcium homeostasis in an in vitro model of Parkinson's disease
复制标题
Homer1 敲低通过调节帕金森病体外模型中的钙稳态来保护多巴胺神经元
DOI：
10.1016/j.cellsig.2013.09.004
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发表时间：
2013-12-01
影响因子：
4.8
通讯作者：
Jiang, Xiao-fan
中科院分区：
文献类型：
--
作者：
Chen, Tao;Yang, Yue-fan;Jiang, Xiao-fan
Hmer 1蛋白是突触后密度的一种重要支架蛋白，已被证明在中枢神经系统钙信号转导中发挥重要作用。本研究旨在探讨Horner1基因敲除对MPP+诱导的多巴胺(DA)神经元损伤的影响。我们发现，用特异的小干扰RNA(SiRNA)下调Hmer 1的表达可显著抑制MPP+损伤后LDH的释放，减少PI或Hoechst染色，增加酪氨酸羟化酶(TH)阳性细胞数和DA摄取，并减轻MPP+损伤后细胞的凋亡和坏死。Hmer-1基因敲除通过抑制细胞内钙超载而减少细胞内活性氧的产生，但不影响内源性抗氧化酶的活性。钙显像法检测细胞内钙离子浓度([Ca~(2+)](Cyt))和内质网(ER)钙离子浓度([Ca~(2+)](ER))的变化。结果表明，在MPP+损伤后120min，Hmer 1 siRNA可抑制内质网钙离子释放。此外，N-甲基-D-天冬氨酸受体拮抗剂MK-801和AP-5可进一步增强Hmer-1基因敲除MPP+引起的神经元内[Ca~(2+)](Cyt)的降低，但不能增强典型的瞬时受体电位通道拮抗剂SKF-96365的作用。L类钙拮抗剂伊拉地平而不是尼莫地平进一步抑制MPP+损伤后Hmer-1下调神经元的细胞内钙超载。这些结果提示，在体外PD模型中，Hmer-1基因敲除通过减少钙超载介导的ROS的产生对神经元损伤具有保护作用，这种保护作用可能至少部分依赖于对质膜和内质网钙通道功能的调节作用。(C)2013 Elsevier Inc.保留所有权利。
Homer1 protein is an important scaffold protein at postsynaptic density and has been demonstrated to play a central role in calcium signaling in the central nervous system. The aim of this study was to investigate the effects of Horner1 knockdown on MPP+ induced neuronal injury in cultured dopamine (DA) neurons. We found that down-regulating Homer1 expression with specific small interfering RNA (siRNA) significantly suppressed LDH release, reduced Propidium iodide (PI) or Hoechst staining, increased the number of tyrosine hydroxylase (TH) positive cells and DA uptake, and attenuated apoptotic and necrotic cell death after MPP+ injury. Homer1 knock-down decreased intracellular reactive oxygen species (ROS) generation through inhibition of intracellular calcium overload, but did not affect the endogenous antioxidant enzyme activities. Calcium imaging was used to examine the changes of intracellular Ca2+ concentration ([Ca2+](cyt)) and Ca2+ in endoplasmic reticulum (ER) ([Ca2+](ER)), and the results showed that Homer1 siRNA transfection attenuated ER Ca2+ release up to 120 min after MPP+ injury. Furthermore, decrease of [Ca2+](cyt) induced by Homer1 knockdown in MPP+ treated neurons was further enhanced by NMDA receptor antagonists MK-801 and AP-5, but not canonical transient receptor potential (TRPC) channel antagonist SKF-96365. L-type calcium antagonist isradipine but not nimodipine further inhibited intracellular calcium overload after MPP+ insult in Homer1 down-regulated neurons. These results suggest that Homer1 knockdown has protective effects against neuronal injury in in vitro PD model by reducing calcium overload mediated ROS generation, and this protection may be dependent at least in part on the regulatory effects on the function of calcium channels in both plasma membrane and ER. (C) 2013 Elsevier Inc. All rights reserved.