以秀丽线虫为模式解析溶酶体功能及动态变化的调控机制

Lysosomes are ubiquitous membrane-bound intracellular organelles that degrade macromolecules delivered by endocytosis, phagocytosis, and autophagy, and export the resulting catabolites for reutilization in cellular metabolism. In addition to cargo digestion and recycling, lysosomes are being recognized as advanced organelles that perform much broader functions and are involved in fundamental cellular processes such as plasma membrane repair, immune response, nutrient sensing and signaling, and cell death. Impairment of lysosome function contributes to the pathogenesis of many diseases including lysosomal storage diseases, neurodegenerative disorders and cancer. .To understand how lysosomes are regulated under physiological conditions, we take advantage of the powerful genetic and cell biological tool in the nematode Caenorhabditis elegans to systemically investigate various aspects of lysosomes including morphology, integrity, function and dynamics. By monitoring lysosomes in live C. elegans, we have observeddynamic changes of lysosomes in worms at different developmental stages, under different culture conditions and during the aging process. By genetic screens, we have isolated mutants with abnormal lysosome morphology and/or dynamics. We will clone the mutated genes and employ combined approachesof genetics, cell biology and biochemistry to 1) reveal their functions in the regulation of lysosome morphology, function and dynamics; 2) elucidate how lysosomes are regulated in and contribute to animal development, aging and stress responses. Given theevolutionary conservation of lysosomal composition and regulation, we will identify the mammalian homologs of the C. elegans genes and investigate their functions in regulating lysosomes and lysosome-related cellularprocesses in mammals. Identification and characterization of these genes will certainly help us to understand how various aspects of lysosomes are regulated under physiological conditions and how theirdysfunction may contribute to the pathogenesis of lysosome-related human diseases.

溶酶体是细胞内负责物质降解和循环的细胞器，在机体发育、代谢平衡及细胞稳态维持中发挥关键作用。溶酶体功能缺陷可引发代谢性及神经退行性疾病等重大疾病。由于溶酶体自身的调控及其参与的细胞学过程非常复杂，目前相关的调控机制多数未被解析。.本项目旨在以秀丽线虫为模式，系统研究溶酶体功能及动态变化的调控机制及其在机体发育及衰老中的作用。项目前期工作建立了溶酶体活体跟踪系统，观察到了溶酶体在不同发育阶段、生长条件及衰老过程中的动态变化。通过遗传筛选，获得了多个溶酶体形态或动态变化异常的突变体。在本项目中，我们将克隆这些突变体的相关基因，利用遗传学、细胞生物学及生物化学等手段解析它们的作用机制，进而揭示溶酶体功能调控、动态变化及稳态维持的调控机制。由于溶酶体组成及调控在进化中高度保守，我们将进一步研究线虫溶酶体调控基因在哺乳动物中同源基因的作用机制，为溶酶体相关疾病的致病机制解析、诊断和治疗提供理论依据。

溶酶体负责物质降解与循环，并作为信号感知及应答中心在细胞稳态平衡中发挥重要作用。溶酶体功能缺陷可引发代谢性及神经退行性疾病等重大疾病。由于溶酶体自身的调控及其参与的细胞学过程非常复杂，目前相关的研究机制多数尚不明晰。在本项目中，我们建立了以线虫为模式的多细胞生物溶酶体研究体系，系统研究溶酶体功能、动态变化及完整性的调控机制及其在机体发育和衰老中的作用。我们鉴定得到多个溶酶体调控基因并解析其作用机制。包括，阐明了溶酶体酸性核酸酶RNST-2调控溶酶体功能和线虫发育的机理；解析了UBC-13调控溶酶体介导的凋亡细胞降解及内吞货物分选的机制；发现了溶酶体酸性磷脂酶LPLA-2调控自噬小体内膜降解及胚胎发育的功能；解析FLN-2在MVB组装及形成过程中的功能。另外，我们的工作揭示了胞外基质到细胞核的信号通路，阐明其在调控溶酶体活性及维护细胞稳态平衡和机体发育中的作用；发现了多个寿命调控通路调控溶酶体功能，以及溶酶体活性在寿命维持中的重要作用；解析了精子发育过程中特化溶酶体等细胞器的非对称分配机制。上述研究成果揭示了多个溶酶体调控基因的作用机制及生理功能，阐明了溶酶体在机体发育和衰老过程中的调控及功能，不仅具有重要的科学意义，也为溶酶体相关疾病的研究提供了理论基础。