Dissecting the role of reproduction in regulating lysosomal function in C. elegans

在真核生物中，繁殖和衰老是相互关联的过程。在不同的物种中，衰老是与生殖周期同步的，因此后代的产生与动物最适合的时间一致。秀丽隐杆线虫中阻止生殖细胞增殖的突变也能延长寿命，这表明生殖腺和体细胞之间存在一种受基因调控的串扰，从而影响了适应性。这种跨组织信号在生殖周期中是如何起作用的，以及它在体细胞中通过哪些细胞过程起作用，目前尚不清楚。我的研究小组正在研究生殖和躯体适应性同步的分子基础。我们最近发现了体细胞中繁殖和溶酶体pH值之间的功能联系，这提供了一个合理的模型来解释秀丽隐杆线虫如何整合来自性腺的信号，通过改善蛋白水解来延缓衰老：在停止繁殖的动物中，溶酶体介导的蛋白水解导致体细胞崩溃和组织退化。这项研究的首要目标是了解与生命史特征（如繁殖和衰老）相关的遗传机制。具体来说，拟议的研究旨在剖析随着动物年龄增长而调节溶酶体功能和蛋白质稳态所需的基因。在目标1中，我们将进一步努力，通过全基因组遗传筛选，分离和表征在生殖期和非生殖期过渡期间触发性腺到体细胞信号所需的基因。我们将利用我们在开发转基因传感器和pH敏感检测方面的专业知识来检测活体蠕虫肠道和肌肉中溶酶体pH值的动态变化，作为这些实验的表型读数。在目标2中，我们将讨论生殖结束后受性腺信号影响的肠细胞的化学成分。我们将采用光谱方法，利用傅里叶变换红外光谱（FTIR）分析，定量测量活肠细胞分子特征的内源性变化。这项工作将利用我们之前在加拿大光源（CLS）下对活秀丽隐杆线虫卵母细胞进行中红外成像的经验，并有望生成衰老相关标记物的详细化学图谱。最后，在目标3中，我们将通过转基因干预控制溶酶体pH来研究溶酶体功能在衰老中的具体影响，然后进行寿命分析。为此，我们将使用转基因和光遗传工具，允许体内囊泡酸化。总之，这些实验将揭示整合生殖信息来调节衰老的新基因。考虑到老化网络的进化保护，我们期望这项研究也与脊椎动物系统相关。

Reproduction and aging are linked processes in eukaryotes. Across different species, aging is synchronized with the reproductive cycle such that progeny generation coincides with the time when the animal is the fittest. Mutations in C. elegans that prevent germ cell proliferation also increase longevity, pointing to a genetically regulated cross talk between the gonad and the soma to influence fitness. How this cross-tissue signaling functions during the reproductive cycle, and through which cellular processes it acts in somatic cells, remains unclear. My research group is studying the molecular underpinning of the synchrony between reproduction and somatic fitness. We have recently identified a functional link between reproduction and lysosomal pH in somatic cells that provides a plausible model to explain how C. elegans integrates signals from the gonad to delay aging via improved proteolysis: in animals that have ceased reproduction, lysosomal-mediated proteolysis in the soma collapses and tissue deterioration ensues. The overarching goal of this research is to understand the genetic mechanisms that connect life history traits, such as reproduction and aging. Specifically, the proposed research aims to dissect the genes necessary to regulate lysosomal function, and consequently protein homeostasis, as animals age. In Objective 1, we will extend our efforts to isolate and characterize the genes required to trigger gonad-to-soma signaling at the transition between reproductive and non-reproductive periods through genome-wide genetic screens. We will use our expertise in developing transgenic sensors and pH-sensitive assays to detect dynamic changes in lysosomal pH in intestine and muscle of live worms as a phenotypic readout for these experiments. In Objective 2, we will address the chemical composition of intestinal cells that are influenced by signaling from the gonad following the end of reproduction. We will take a spectroscopic approach to quantitatively measure endogenous changes in the molecular signatures of live intestinal cells using Fourier-Transform Infrared Spectroscopy (FTIR) analysis. This work will take advantage of our previous experience in Mid-IR imaging of live C. elegans oocytes at the Canadian Light Source (CLS) and is expected to generate a detailed chemical map of aging-associated markers. Finally, in Objective 3, we will investigate the specific impact of lysosomal function in aging by using transgenic interventions to control lysosomal pH, followed by lifespan analyses. To this end, we will use transgenic and optogenetic tools that allow for in vivo vesicle acidification. In summary, these experiments will reveal novel genes that integrate reproductive information to modulate aging. Considering the evolutionary conservation of aging networks, we expect this research to be relevant to vertebrate systems as well.