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標題: | 粒線體鈣離子湧入導致之活性氧類釋放活化細胞自噬 Mitochondrial ROS release triggered by calcium influx activates autophagy |
作者: | Ke Shan 單可 |
指導教授: | 楊維元 |
關鍵字: | 細胞自噬,內質網與粒線體交界處,活性氧類,鈣離子,飢餓,細胞膜損壞,Atg4, Autophagy,ER-mitochondria contact sites,ROS,calcium,starvation,plasma membrane damage,Atg4, |
出版年 : | 2019 |
學位: | 碩士 |
摘要: | 細胞自噬為細胞吞食自身組成物的機制,其目的在於維持細胞正常功能與健康。細胞飢餓時,細胞自噬體主要形成於內質網與粒線體交界處。目前研究仍不清楚細胞如何即時在該處激發自噬體生成。因此,本篇研究著重於探討內質網與粒線體的鈣離子、活性氧類訊息傳導路徑如何在此處調控細胞自噬體生成。我們使用共軛焦顯微鏡觀察活細胞之細胞自噬活性,並在處理鈣離子、活性氧類抑制物後偵測細胞自噬活性的改變。我們發現細胞自噬活性在飢餓10-15分鐘時有顯著增加。另外,細胞自噬激發發生前,我們觀察到鈣離子湧入粒線體、粒線體活性氧類製造與釋放增加,而抑制這些現象導致細胞自噬激發消失。我們實驗室先前研究中發現同時期之 LC3去連結酶Atg4活性受抑制。此外,我們看到細胞膜損壞所引起之細胞自噬受粒線體活性氧類釋放調控。綜合以上結果,我們提出以下模式:短期飢餓時,鈣離子進入粒線體,引發粒線體製造並釋出活性氧類。釋出之活性氧類透過抑制該處Atg4以活化細胞自噬。此鈣離子活性氧類調控路徑為一普遍細胞自噬控制機制。此路徑不僅參與飢餓與細胞膜損壞引起的細胞自噬,也可能影響其他跟鈣離子擾動相關的細胞自噬活化。 Autophagy, a self-digestive mechanism, is vital for cellular functions and health. During starvation, autophagosomes form mainly at the endoplasmic reticulum (ER)-mitochondria contact sites. However, how cells timely induce autophagy at these sites are unclear. We aimed to elucidate the roles of ER and mitochondrial calcium-reactive oxygen species (ROS) signaling in autophagosome formation at these sites. We used confocal live-cell imaging to monitor autophagy activity in the absence or presence of calcium and ROS inhibitors. We found that autophagy activity burst at 10-15 minutes of starvation. The autophagy burst was preceded by mitochondrial calcium influx, mitochondrial ROS production and release; the inhibition of these phenomena abolished autophagy burst. Previously, our lab saw Atg4, an LC3 de-conjugating enzyme, was inhibited in the same time frame. Additionally, autophagy induced by plasma membrane damage was also controlled by mitochondrial ROS release. Taken together, we propose that during short-term starvation, mitochondrial calcium influx induces ROS production and release. ROS then facilitate autophagy by local Atg4 inhibition. This calcium-ROS signaling pathway may represent a general autophagy regulatory mechanism in starvation, plasma membrane damage and other autophagy stimuli that involve calcium perturbations. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/7322 |
DOI: | 10.6342/NTU201901295 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 生化科學研究所 |
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