Department of Neurosurgery, Xiangya Hospital, Central-South University, Changsha, Hunan 410008, China.
Department of Neurosurgery, Xiangya Hospital, Central-South University, Changsha, Hunan 410008, China.
Biochem Biophys Res Commun. 2014 Jan 3;443(1):138-43. doi: 10.1016/j.bbrc.2013.11.072. Epub 2013 Nov 24.
Glutamate-mediated excitotoxicity is involved in many acute and chronic brain diseases. Dynamin related protein 1 (Drp-1), one of the GTPase family of proteins that regulate mitochondrial fission and fusion balance, is associated with apoptotic cell death in cancer and neurodegenerative diseases. Here we investigated the effect of downregulating Drp-1 on glutamate excitotoxicity-induced neuronal injury in HT22 cells. We found that downregulation of Drp-1 with specific small interfering RNA (siRNA) increased cell viability and inhibited lactate dehydrogenase (LDH) release after glutamate treatment. Downregulation of Drp-1 also inhibited an increase in the Bax/Bcl-2 ratio and cleavage of caspase-9 and caspase-3. Drp-1 siRNA transfection preserved the mitochondrial membrane potential (MMP), reduced cytochrome c release, enhanced ATP production, and partly prevented mitochondrial swelling. In addition, Drp-1 knockdown attenuated glutamate-induced increases of cytoplasmic and mitochondrial Ca(2+), and preserved the mitochondrial Ca(2+) buffering capacity after excitotoxicity. Taken together, these results suggest that downregulation of Drp-1 protects HT22 cells against glutamate-induced excitatory damage, and this neuroprotection may be dependent at least in part on the preservation of mitochondrial function through regulating intracellular calcium homeostasis.
谷氨酸介导的兴奋毒性参与许多急性和慢性脑部疾病。动力相关蛋白 1（Drp-1）是调节线粒体分裂和融合平衡的 GTPase 家族蛋白之一，与癌症和神经退行性疾病中的凋亡细胞死亡有关。在这里，我们研究了下调 Drp-1 对 HT22 细胞中谷氨酸兴奋性毒性诱导的神经元损伤的影响。我们发现，用特异性小干扰 RNA（siRNA）下调 Drp-1 可增加谷氨酸处理后的细胞活力并抑制乳酸脱氢酶（LDH）释放。下调 Drp-1 还抑制了 Bax/Bcl-2 比值的增加以及 caspase-9 和 caspase-3 的切割。Drp-1 siRNA 转染可保持线粒体膜电位（MMP），减少细胞色素 c 的释放，增强 ATP 的产生，并部分防止线粒体肿胀。此外，Drp-1 敲低可减轻谷氨酸诱导的细胞质和线粒体 Ca（2+）增加，并在兴奋毒性后保持线粒体 Ca（2+）缓冲能力。总之，这些结果表明，下调 Drp-1 可保护 HT22 细胞免受谷氨酸诱导的兴奋毒性损伤，这种神经保护作用至少部分依赖于通过调节细胞内钙稳态来维持线粒体功能。
