氧化鋅奈米粒子經由活化MAP Kinase與蛋白質聚泛素化誘導自噬性細胞死亡

Zinc Oxide Nanoparticles Induce Autophagic Cell Death Via MAP Kinase Activation And Protein Poly-ubiquitination

陳俞伶(Yu-Ling Chen)

指導教授 ： 周正中

國立中正大學/理學院/生命科學系分子生物研究所/碩士(2014年)

摘要

氧化鋅奈米粒子是最廣泛使用在食品與產品上的奈米材質之一，因此人類更容易暴露於氧化鋅奈米粒子中並對人體健康的風險提高。氧化鋅奈米粒子的安全評估在近幾年已有深入研究和探討，但有關於氧化鋅奈米粒子的毒性作用分子機制仍並不清楚。因此為了達到這目的，我們使用Macrophage與人類肺部細胞株BEAS-2做為肺部細胞模型，以研究評估氧化鋅奈米粒子對細胞毒性作用所牽涉的機制為何。我們的結果證明，細胞能夠輕易的將氧化鋅奈米粒子攝取至細胞內，然後奈米粒子會結合到許多細胞內的蛋白質，最終導致吸附在奈米粒子表面上的蛋白質被聚泛素化 (poly-ubiquitination)。其結果是透過共軛焦顯微鏡發現細胞產生自噬泡 (autophagic vacuoles)與被泛素標記的蛋白質是位於相同位置，表示自噬泡被誘導後包裹著大量被泛素化的蛋白質並將它們進行降解。另一方面，氧化鋅奈米粒子透過活化JNK、ERK與p38 MAPK，使細胞產生氧化壓力反應，並隨後引此自噬性的細胞死亡。本篇研究證明氧化鋅奈米粒子經由活化MAPK訊息傳遞路徑與蛋白質聚泛素化誘導自噬性細胞死亡，提供了一種氧化鋅奈米粒子對細胞的毒性作用機制。

關鍵字

氧化鋅奈米粒子

並列摘要

Zinc oxide nanoparticles (ZnO-NPs) are one of the most widely used nanomaterials in the food and product market, therefore the potential for human exposure to the nanoparticles is raising an important health risks. The safety assessment of ZnO-NPs has been studies intensively recently, but the underlying molecular mechanisms about the toxicity of ZnO-NPs remain unclear. To address this issue, we performed a comprehensive study to assess ZnO-NP toxicity in both macrophages and human lung cell line BEAS-2B – a two-cell type of lung model. Our results indicate that ZnO-NPs can be easily uptaken into the cells, then bind to many cellular proteins, and finally induce the poly-ubiquitination of these adsorbed protein molecules. As a result, autophagy was induced to coordinately degrade the massive ubiquitinated proteins since the ubiquitin-tagged proteins were found to colocalize with the autophagic vacuoles by confocal microscopy. On the other hand, ZnO-NPs induced oxidative stress to activate JNK, p38 and ERK MAP kinase cascades and subsequently cause autophagic cell death. The present study has demonstrated that ZnO-NPs can induce autophagic cell death via MAP Kinase activation and protein poly-ubiquitination, and provids valuable insights into the molecular mechanism of ZnO-NP-associated toxicity.

並列關鍵字

ZnO nanoparticles

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