Tang Ho Lam, Tang Ho Man, Fung Ming Chiu, Hardwick J Marie
1] W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205 USA [2] School of Life Sciences and Center for Soybean Research of the State Key Laboratory of Agrobiotechnology, Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205 USA.
Sci Rep. 2015 Mar 11;5:9015. doi: 10.1038/srep09015.
The discovery that mammalian cells can survive late-stage apoptosis challenges the general assumption that active caspases are markers of impending death. However, tools have not been available to track healthy cells that have experienced caspase activity at any time in the past. Therefore, to determine if cells in whole animals can undergo reversal of apoptosis, known as anastasis, we developed a dual color CaspaseTracker system for Drosophila to identify cells with ongoing or past caspase activity. Transient exposure of healthy females to environmental stresses such as cold shock or starvation activated the CaspaseTracker coincident with caspase activity and apoptotic morphologies in multiple cell types of developing egg chambers. Importantly, when stressed flies were returned to normal conditions, morphologically healthy egg chambers and new progeny flies were labeled by the biosensor, suggesting functional recovery from apoptotic caspase activation. In striking contrast to developing egg chambers, which lack basal caspase biosensor activation under normal conditions, many adult tissues of normal healthy flies exhibit robust caspase biosensor activity in a portion of cells, including neurons. The widespread persistence of CaspaseTracker-positivity implies that healthy cells utilize active caspases for non-apoptotic physiological functions during and after normal development.
哺乳动物细胞能够在晚期凋亡中存活这一发现，挑战了活性半胱天冬酶是即将死亡标志的普遍假设。然而，此前并没有工具可用于追踪过去任何时候经历过半胱天冬酶活性的健康细胞。因此，为了确定完整动物体内的细胞是否能够经历凋亡逆转（即回生），我们开发了一种用于果蝇的双色半胱天冬酶追踪系统，以识别具有正在进行或过去半胱天冬酶活性的细胞。健康雌性果蝇短暂暴露于冷休克或饥饿等环境应激下，会激活半胱天冬酶追踪系统，同时在发育中的卵室的多种细胞类型中出现半胱天冬酶活性和凋亡形态。重要的是，当应激果蝇恢复到正常条件时，形态上健康的卵室和新的子代果蝇被生物传感器标记，这表明从凋亡半胱天冬酶激活中实现了功能恢复。与在正常条件下缺乏基础半胱天冬酶生物传感器激活的发育中的卵室形成鲜明对比的是，正常健康果蝇的许多成年组织在包括神经元在内的一部分细胞中表现出强大的半胱天冬酶生物传感器活性。半胱天冬酶追踪阳性的广泛持续存在意味着健康细胞在正常发育期间及之后利用活性半胱天冬酶进行非凋亡生理功能。
