Anthranilate fluorescence marks a calcium-propagated necrotic wave that promotes organismal death in C. elegans.
Anthranilate fluorescence marks a calcium-propagated necrotic wave that promotes organismal death in C. elegans.
复制标题
DOI：
10.1371/journal.pbio.1001613
复制
发表时间：
2013-07
期刊：
影响因子：
9.8
通讯作者：
Gems D
中科院分区：
文献类型：
--
作者：
Coburn C;Allman E;Mahanti P;Benedetto A;Cabreiro F;Pincus Z;Matthijssens F;Araiz C;Mandel A;Vlachos M;Edwards SA;Fischer G;Davidson A;Pryor RE;Stevens A;Slack FJ;Tavernarakis N;Braeckman BP;Schroeder FC;Nehrke K;Gems D
秀丽隐杆线虫的死亡涉及保守的坏死细胞死亡级联，其产生内源性蓝色邻氨基苯甲酸荧光，允许死亡可视化。对于细胞来说，从生到死的过程可能涉及到一个受调节的、程序化的过渡。与细胞死亡相反，生物体死亡背后的系统性崩溃机制仍然知之甚少。在这里，我们提出了一个级联的细胞死亡的证据，涉及钙蛋白酶-组织蛋白酶坏死途径，可以驱动有机体死亡秀丽隐杆线虫。我们报告说，生物体死亡伴随着强烈的蓝色荧光爆发，在肠细胞内产生的坏死细胞死亡途径。这种死亡荧光标志着伴随胞质酸中毒的肠细胞死亡的前后波。该波通过连接蛋白INX-16传播，可能是通过钙内流。值得注意的是，抑制全身性坏死可以延迟应激诱导的死亡。我们还确定了蓝色荧光的来源，最初存在于肠道溶酶体相关的细胞器（肠道颗粒），邻氨基苯甲酸葡萄糖酯，而不是像以前推测的，损伤产物脂褐素。邻氨基苯甲酸通过犬尿氨酸途径的作用衍生自色氨酸。这些发现揭示了C.与哺乳动物中的坏死繁殖有关的线虫-例如，兴奋性毒性和局部缺血引起的神经变性。内源性邻氨基苯甲酸荧光呈现可见的时空动态的C。elegans有机体的死亡。在线虫秀丽隐杆线虫中，肠溶酶体相关的细胞器（或“肠颗粒”）含有一种未知身份的亮蓝色荧光物质。这与脂褐素具有相似的光谱特性，脂褐素是一种已知在有丝分裂后哺乳动物细胞中随着年龄的增长而积累的氧化损伤产物。蓝色荧光似乎在老化的蠕虫种群中增加，脂褐质被认为是来源。为了进一步分析这一点，我们测量荧光水平暴露于氧化应激后，并在老化过程中单独跟踪蠕虫。令人惊讶的是，这两种情况都没有增加荧光水平;相反，蓝色荧光在死亡时以惊人的快速爆发增加。这种死亡荧光（DF）也出现在年轻的蠕虫杀死时，无论年龄或死因。我们化学鉴定DF为来自色氨酸的邻氨基苯甲酸葡萄糖酯，而不是脂褐质。此外，我们表明，DF在肠道中的产生依赖于坏死细胞死亡级联反应，以前的特点是作为一个驱动程序的神经变性。我们发现，坏死扩散迅速波沿着肠钙内流通过连接蛋白离子通道，伴随着胞质酸中毒。抑制坏死途径成分可以延迟应激诱导的死亡，支持其作为生物体死亡驱动因素的作用。这种坏死级联反应为研究神经变性和生物体死亡提供了模型系统。
Death of the nematode Caenorhabditis elegans involves a conserved necrotic cell death cascade which generates endogenous blue anthranilate fluorescence, allowing death to be visualized. For cells the passage from life to death can involve a regulated, programmed transition. In contrast to cell death, the mechanisms of systemic collapse underlying organismal death remain poorly understood. Here we present evidence of a cascade of cell death involving the calpain-cathepsin necrosis pathway that can drive organismal death in Caenorhabditis elegans. We report that organismal death is accompanied by a burst of intense blue fluorescence, generated within intestinal cells by the necrotic cell death pathway. Such death fluorescence marks an anterior to posterior wave of intestinal cell death that is accompanied by cytosolic acidosis. This wave is propagated via the innexin INX-16, likely by calcium influx. Notably, inhibition of systemic necrosis can delay stress-induced death. We also identify the source of the blue fluorescence, initially present in intestinal lysosome-related organelles (gut granules), as anthranilic acid glucosyl esters—not, as previously surmised, the damage product lipofuscin. Anthranilic acid is derived from tryptophan by action of the kynurenine pathway. These findings reveal a central mechanism of organismal death in C. elegans that is related to necrotic propagation in mammals—e.g., in excitotoxicity and ischemia-induced neurodegeneration. Endogenous anthranilate fluorescence renders visible the spatio-temporal dynamics of C. elegans organismal death. In the nematode Caenorhabditis elegans, intestinal lysosome-related organelles (or “gut granules”) contain a bright blue fluorescent substance of unknown identity. This has similar spectral properties to lipofuscin, a product of oxidative damage known to accumulate with age in postmitotic mammalian cells. Blue fluorescence seems to increase in aging worm populations, and lipofuscin has been proposed to be the source. To analyze this further, we measure fluorescence levels after exposure to oxidative stress and during aging in individually tracked worms. Surprisingly, neither of these conditions increases fluorescence levels; instead blue fluorescence increases in a striking and rapid burst at death. Such death fluorescence (DF) also appears in young worms when killed, irrespective of age or cause of death. We chemically identify DF as anthranilic acid glucosyl esters derived from tryptophan, and not lipofuscin. In addition, we show that DF generation in the intestine is dependent upon the necrotic cell death cascade, previously characterized as a driver of neurodegeneration. We find that necrosis spreads in a rapid wave along the intestine by calcium influx via innexin ion channels, accompanied by cytosolic acidosis. Inhibition of necrosis pathway components can delay stress-induced death, supporting its role as a driver of organismal death. This necrotic cascade provides a model system to study neurodegeneration and organismal death.
登录
查看更多内容
影响因子：
5.5
作者：
Allman, Erik;Johnson, David;Nehrke, Keith
通讯作者：
Nehrke, Keith
影响因子：
15
作者：
Forseth, Ry R.;Fox, Ellen M.;Chung, DaWoon;Howlett, Barbara J.;Keller, Nancy P.;Schroeder, Frank C.
通讯作者：
Schroeder, Frank C.
影响因子：
3.3
作者：
Hermann, GJ;Schroeder, LK;Priess, JR
通讯作者：
Priess, JR
影响因子：
64.8
作者：
Herndon, LA;Schmeissner, PJ;Driscoll, M
通讯作者：
Driscoll, M
影响因子：
56.9
作者：
ELDRED, GE;MILLER, GV;FEENEYBURNS, L
通讯作者：
FEENEYBURNS, L