Mitochondrial Injury after Mechanical Stretch of Cortical Neurons in vitro: Biomarkers of Apoptosis and Selective Peroxidation of Anionic Phospholipids
Mitochondrial Injury after Mechanical Stretch of Cortical Neurons in vitro: Biomarkers of Apoptosis and Selective Peroxidation of Anionic Phospholipids
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DOI：
10.1089/neu.2010.1602
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发表时间：
2012-03-01
影响因子：
4.2
通讯作者：
Bayir, Huelya
中科院分区：
文献类型：
--
作者：
Ji, Jing;Tyurina, Yulia Y.;Bayir, Huelya
机械性损伤神经突并伴有线粒体膜破裂可导致促凋亡因子的立即非特异性释放和扩散以及蛋白酶的激活，即凋亡程序的执行。在目前的工作中，我们研究了细胞凋亡的主要生物标志物的时间过程，因为它们是由大鼠皮层神经元暴露于机械拉伸诱导的。通过使用透射电子显微镜，我们发现，线粒体在神经突损伤后早期（1小时）机械拉伸损伤，而体线粒体显着更具抵抗力，并表现出结构损伤和退行性线粒体变化后的时间点拉伸（12小时）。我们还报告说，牵张损伤引起的活性氧产生的立即激活，然后选择性氧化的一个特定的磷脂，心磷脂，其个人过氧化的分子物种已被确定和量化的电喷雾电离质谱分析。最丰富的神经元磷脂-磷脂酰胆碱，磷脂酰乙醇胺-没有进行氧化修饰。同时，观察到细胞色素c的小规模释放。值得注意的是，半胱天冬酶激活和磷脂酰丝氨酸外化-两个不可逆的凋亡事件指定一个点不返回-大大延迟，并不发生，直到6-12小时后，最初的影响。活性氧产生和细胞色素c释放的早期发作可能与直接牵张诱导的线粒体损伤有关。在对线粒体的直接机械损伤之后，细胞凋亡性神经元死亡的延迟出现提示了靶向治疗的可能的机会窗口。
Mechanical injury of neurites accompanied by rupture of mitochondrial membranes may lead to immediate nonspecific release and spreading of pro-apoptotic factors and activation of proteases, that is, execution of apoptotic program. In the current work, we studied the time course of the major biomarkers of apoptosis as they are induced by exposure of rat cortical neurons to mechanical stretch. By using transmission electron microscopy, we found that mitochondria in the neurites were damaged early (1 h) after mechanical stretch injury whereas somal mitochondria were significantly more resistant and demonstrated structural damage and degenerative mitochondrial changes at a later time point after stretch (12 h). We also report that the stretch injury caused immediate activation of reactive oxygen species production followed by selective oxidation of a mitochondria-specific phospholipid, cardiolipin, whose individual peroxidized molecular species have been identified and quantified by electrospray ionization mass spectrometry analysis. Most abundant neuronal phospholipids - phosphatidylcholine, phophatidylethanolamine - did not undergo oxidative modification. Simultaneously, a small-scale release of cytochrome c was observed. Notably, caspase activation and phosphatidylserine externalization - two irreversible apoptotic events designating a point of no return - are substantially delayed and do not occur until 6-12 h after the initial impact. The early onset of reactive oxygen species production and cytochrome c release may be relevant to direct stretch-induced damage to mitochondria. The delayed emergence of apoptotic neuronal death after the immediate mechanical damage to mitochondria suggests a possible window of opportunity for targeted therapies.