Investigating the relationship between mitochondrial dysfunction and apoptosis, autophagy and cellular senescence

除了能量产生，线粒体在细胞凋亡、自噬和衰老中起着至关重要的作用。氧化还原信号传导、自噬、衰老和线粒体功能障碍之间的关系/串扰尚未得到很好的理解。 据推测，有毒蛋白质（氧化或亚硝基化）的积累和功能障碍的ceptin导致进一步的氧化应激，可能导致任何上述现象。自噬是为了消除功能失调的蛋白质和细胞器而诱导的。然而，如果自噬被抑制，则细胞死亡（在神经元系统中）或衰老（在成纤维细胞中）被激活。 使用具有野生型和早老素-1突变的正常人成纤维细胞作为模型，该研究计划旨在研究触发衰老，凋亡和自噬的细胞开关机制以及线粒体在这些过程中的作用。与所提出的计划相关，我们已经开发了一种优秀的原代人皮肤成纤维细胞（NHF）与野生型早老素-1（PS-1）和突变的PS-1的细胞模型，用于研究这三种现象1。我们已经确定PS-1突变的NHF具有：a）增加活性氧（ROS）的产生; B）MnSOD、p21、p16和Rb的上调，导致过早衰老和增殖细胞核抗原（PCNA）的下调; c）降低自噬水平; d）抵抗由外部氧化应激引起的细胞凋亡。 此外，我们发现水溶性CoQ 10（WS CoQ 10）抑制PS-1突变细胞的过早衰老，并导致这些细胞自噬的恢复。然而，由于PS-1突变导致的线粒体功能的确切缺陷仍然不清楚，响应于ROS产生增加而诱导衰老或自噬的生化开关仍然未知。WS CoQ 10如何恢复PS-1突变成纤维细胞中的自噬诱导仍然是一个非常重要和有趣的问题，尚未得到回答。为了解决上述知识空白，本项目提出以下研究目标：*1）PS-1突变成纤维细胞（PSMF）线粒体功能障碍的研究。* 2.表征从线粒体氧化应激到衰老、自噬或凋亡的信号级联。成功完成该计划将导致我们对衰老，自噬和凋亡机制以及这些基本细胞过程之间错综复杂的关系的理解。 **

In addition to energy production, the mitochondria play a crucial role in apoptosis, autophagy and senescence. The relationship/crosstalk between redox signaling, autophagy, senescence and mitochondrial dysfunction is not well understood. It is hypothesized that accumulation of toxic proteins (oxidized or nitrosylated) and malfunctioning of mitochondrion lead to further oxidative stress that could lead to any of the aforementioned phenomena. Autophagy is induced in response to such stress in order to eliminate dysfunctional proteins and organelles. However, if autophagy is inhibited, cell death (in the neuronal system) or senescence (in fibroblasts) is activated. Using normal human fibroblasts with wild type and Presenilin-1 mutations as models, the research program is set to investigate the mechanism of cellular switches that trigger senescence, apoptosis and autophagy and role of mitochondria in these processes.***Relevant to the proposed program, we have developed an excellent cellular model of primary human skin fibroblasts (NHFs) with wild type presenilin-1 (PS-1) and those with mutated PS-1 for the study of the three phenomenons1. We have established that the NHFs with PS-1 mutation have: a) increased production of reactive oxygen species (ROS); b) upregulation of MnSOD, p21, p16, and Rb, leading to premature senescence and downregulation of proliferating cell nuclear antigen (PCNA); c) decreased levels of autophagy; d) resistance to apoptosis caused by external oxidative stress. Furthermore, we discovered that water-soluble CoQ10 (WS CoQ10) inhibits premature senescence in PS-1 mutant cells and causes resumption of autophagy in these cells1. However, the exact deficiency in the mitochondrial function due to the PS-1 mutation is still not understood, the biochemical switch for the induction of either senescence or autophagy in response to increased generation of ROS remains unknown. How does WS CoQ10 restore autophagic induction in PS-1 mutated fibroblasts remains a very important and interesting question, yet to be answered. In order to address the aforementioned knowledge gap, this program proposes the following research aims: ***1) Investigation of mitochondrial dysfunction in PS-1 mutated fibroblasts (PSMF).***2. Characterization of signalling cascades from mitochondrial oxidative stress to senescence, autophagy, or apoptosis.***Successful completion of this program will lead to our advancement of understanding of the mechanism of senescence, autophagy, and apoptosis and the intricate relationship between these fundamental cellular processes.  **