The human salivary peptide histatin 5 exerts its antifungal activity through the formation of reactive oxygen species
The human salivary peptide histatin 5 exerts its antifungal activity through the formation of reactive oxygen species
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DOI：
10.1073/pnas.141366998
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发表时间：
2001-12-04
影响因子：
11.1
通讯作者：
Oppenheim, FG
中科院分区：
文献类型：
--
作者：
Helmerhorst, EJ;Troxler, RF;Oppenheim, FG
以前的研究表明，人唾液抗真菌多肽组蛋白5被白色念珠菌细胞摄取，并与线粒体结合。本研究的目的是研究这种特定的亚细胞靶向的生物学后果。组蛋白5以剂量和时间依赖的方式抑制分离的白色念珠菌线粒体的呼吸和完整胚泡分生孢子的呼吸。在对数或稳定期细胞中，观察到组蛋白诱导的呼吸抑制和细胞杀伤之间几乎完全相关，但稳定期细胞不那么敏感。由于不呼吸的酵母细胞对组蛋白5不敏感，因此利用氧自由基敏感的探针(二氢乙二胺)探索了组蛋白5对呼吸器官的干扰和细胞杀伤之间的潜在机制关系。荧光测定法表明，组蛋白5可诱导白念珠菌细胞和分离的线粒体产生活性氧(ROS)，且ROS水平与细胞死亡高度相关。在氧气清除剂(L-半胱氨酸)存在下，细胞杀伤和ROS的形成被阻止。此外，膜超氧化物歧化酶模拟物2，2，6，6-四甲基哌啶-N-氧基，可消除组蛋白诱导的线粒体ROS的形成。与组蛋白5不同的是，传统的呼吸链抑制剂氰化钠或叠氮钠既不会诱导ROS，也不会杀死酵母细胞。这些数据为组蛋白-5引起酵母细胞死亡的全面机制模型提供了强有力的证据，在该模型中，氧自由基的形成是最终和必要的步骤。
Previous studies have shown that the human salivary antifungal peptide histatin 5 is taken up by Candida albicans cells and associates intracellularly with mitochondria. The purpose of the present study was to investigate the biological consequence of this specific subcellular targeting. Histatin 5 inhibited respiration of isolated C. albicans mitochondria as well as the respiration of intact blastoconidia in a dose and time-dependent manner. A nearly perfect correlation was observed between histatin-induced inhibition of respiration and cell killing with either logarithmic- or stationary-phase cells, but stationary-phase cells were less sensitive. Because nonrespiring yeast cells are insensitive to histatin 5, the potential mechanistic relationship between histatin 5 interference with the respiratory apparatus and cell killing was explored by using an oxygen radical sensitive probe (dihydroethidium). Fluorimetric measurements showed that histatin 5 induced the formation of reactive oxygen species (ROS) in C. albicans cells as well as in isolated mitochondria and that ROS levels were highly correlated with cell death. In the presence of an oxygen scavenger (L-cysteine), cell killing and ROS formation were prevented. to addition, the membrane-permeant superoxide dismutase mimetic 2,2,6,6-tetramethylpiperidine-N-oxyl, abolished histatin-induced ROS formation in isolated mitochondria. In contrast to histatin 5, the conventional inhibitors of the respiratory chain, sodium cyanide or sodium azide, neither induced ROS nor killed yeast cells. These data provide strong evidence for a comprehensive mechanistic model of histatin-5-provoked yeast cell death in which oxygen radical formation is the ultimate and essential step.