D'Orsi Beatrice, Niewidok Natalia, Düssmann Heiko, Prehn Jochen H M
Department of Physiology & Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland.
Institute of Neuroscience, Italian National Research Council, Pisa, Italy.
Front Cell Dev Biol. 2021 Oct 11;9:750100. doi: 10.3389/fcell.2021.750100. eCollection 2021.
The BH3 interacting-domain death agonist (BID) is a pro-apoptotic member of the Bcl-2 protein family. While proteolytic processing of BID links death receptor-induced apoptosis to the mitochondrial apoptosis pathway, we previously showed that full length BID also translocates to mitochondria during Ca-induced neuronal cell death. Moreover, mitochondrial carrier homolog 2 (MTCH2) was identified as a mitochondrial protein that interacts with BID during cell death. We started our studies by investigating the effect of silencing in a well-established model of Ca-induced mitochondrial permeability transition pore opening in non-neuronal HCT116 cells. We found that silencing of inhibited mitochondrial swelling and the associated decrease in mitochondrial energetics, suggesting a pro-death function for MTCH2 during Ca-induced injury. Next, we explored the role of BID and MTCH2 in mediating Ca-induced injury in primary cortical neurons triggered by prolonged activation of NMDA glutamate receptors. Analysis of intracellular Ca transients, using time-lapse confocal microscopy, revealed that neurons lacking showed markedly reduced Ca levels during the NMDA excitation period. These Ca transients were further decreased when was also silenced. Collectively, our data suggest that BID and MTCH2 functionally interact to promote Ca-induced neuronal injury.
BH3相互作用结构域死亡激动剂（BID）是Bcl-2蛋白家族的促凋亡成员。虽然BID的蛋白水解加工将死亡受体诱导的细胞凋亡与线粒体凋亡途径联系起来，但我们之前表明，全长BID在钙诱导的神经元细胞死亡过程中也会转位至线粒体。此外，线粒体载体同源物2（MTCH2）被鉴定为一种在细胞死亡期间与BID相互作用的线粒体蛋白。我们通过在已建立的非神经元HCT116细胞钙诱导的线粒体通透性转换孔开放模型中研究基因沉默的作用来开展我们的研究。我们发现，MTCH2基因沉默可抑制线粒体肿胀以及线粒体能量代谢的相关降低，这表明MTCH2在钙诱导的损伤过程中具有促死亡功能。接下来，我们探讨了BID和MTCH2在介导由NMDA谷氨酸受体长时间激活引发的原代皮质神经元钙诱导损伤中的作用。使用延时共聚焦显微镜对细胞内钙瞬变进行分析，结果显示，缺乏MTCH2的神经元在NMDA兴奋期的钙水平明显降低。当BID也被沉默时，这些钙瞬变进一步降低。我们的数据共同表明，BID和MTCH2在功能上相互作用以促进钙诱导的神经元损伤。
