Extracellular vesicles in cellular aging

细胞代谢功能和复制能力的逐渐下降是衰老的标志，也是人类寿命的主要决定因素。这些变化在所有细胞类型和物种中都是高度保守的，并且是可修改的：在疾病中加速，但可以通过重新编程来延缓衰老和延长寿命。我们和其他人已经证明，通过外膜泡（外泌体途径）释放的大ev诱导衰老。相反，我们的初步数据表明，内体途径产生的小ev保留了功能和复制能力。本研究项目旨在探索ev在细胞-细胞通信中衰老过程中的作用，以发现优化细胞衰老的新方法。在接下来的五年中，我们将测试衰老细胞经历表型转变的特定假设，即从释放保留细胞功能的内体细胞源性ev到诱导继发性衰老和进行性细胞衰老的外体细胞源性ev。我们将重点研究三个问题：1。衰老细胞是否经历从内体分泌EV到外体分泌EV的转变？我们将研究来自早衰症患者的复制性衰老、应激性早衰和成纤维细胞模型，并比较释放到细胞外环境中的ev的表型。我们量化EV水平并评估单个EV亚群的变化。我们将把特定EV亚群（外泌体、arrdc1介导的微泡[小外泌体]和微泡[大外泌体]）的水平与细胞中的衰老信号联系起来，并评估可能导致EV异常分泌的失调途径。2. 电动汽车是否调节靶细胞的细胞衰老途径？我们将评估EV亚群对靶细胞细胞衰老途径的影响。我们将测试来自衰老群体的ev是否会诱导继发性衰老，以及来自年轻/健康细胞的ev是否能抑制衰老。我们将通过蛋白质组学寻找负责EV信号传导的候选蛋白。3. 衰老细胞能否被重编程为内体分泌EV，从而减轻继发性衰老？最后，我们将测试是否有可能重新编程细胞以保留其分泌内体ev的能力。我们将测试3种方法。1)诱导内体EV的形成；2)抑制外泌体EV的形成；3)通过靶向一种新的分子开关（二酰基甘油激酶？），将EV的形成从外泌体重定向到内泌体途径。我们提出的研究计划将在细胞水平上加强对人类衰老过程的理解。如果成功，该项目可能会发现新的治疗干预靶点，以抑制细胞衰老和延缓衰老。反过来，这可能有助于减轻老龄化和与年龄相关的发病率对加拿大人口迅速老龄化的影响。

The progressive decline in cellular metabolic function and replicative capacity is a hallmark of aging and a central determinant of human lifespan. These changes are highly conserved across all cell types and species and modifiable: accelerated in disease, but amenable to reprogramming to delay senescence and extend lifespan. We, and others, have shown that large EVs released through outward membrane blebbing (ectosomal pathway) induce senescence. Conversely, our preliminary data suggest that small EVs arising from endosomal pathways preserve function and replicative capacity. This research program explores the role of EVs in cell-cell communications in aging with the goal of discovering novel approaches to optimize cellular aging throughout life. Over the next five years we will test the specific hypothesis that senescent cells undergo a phenotypic shift from release of endosomal-derived EVs which preserve cell function to ectosomal-derived EVs which induce secondary senescence and progressive cellular aging. We will focus on three research questions: 1. Do aging cells undergo a shift from endosomal EV secretion to ectosomal EV secretion? We will examine models of replicative senescence, stress-induced premature senescence, and fibroblasts from individuals with progeria and compare the phenotype of EVs released into the extracellular environment. We quantify EV levels and assess changes in individual EV subpopulations. We will correlate levels of specific EV subpopulations (exosomes, ARRDC1-mediated microvesicles [small ectosomes], and microvesicles [large ectosomes]) with senescent signaling in cells and assess dysregulated pathways that may be responsible for aberrant EV secretion. 2. Do EVs regulate cellular aging pathways in target cells. We will assess the effects of EV subpopulations on cellular aging pathways in target cells. We will test whether EVs from senescent populations induce secondary senescence as well as whether EVs from young/healthy cells can inhibit senescence. We will seek to identify candidate proteins responsible for EV signaling by proteomics. 3. Can aging cells be reprogrammed to endosomal EV secretion, attenuating secondary senescence? Finally we will test whether it is possible to reprogram cells to retain their ability to secrete endosomal EVs. We will test 3 approaches. 1) Induction of endosomal EV formation, 2) Inhibition of ectosomal EV formation, and 3) Redirection of EV formation from ectosomal to endosomal pathways by targeting a novel molecular switch (diacylglycerol kinase ?) recently identified in collaboration with Dr. Stephen Gee. Our proposed research program will enhance understanding of the human ageing process at the cellular level. If successful, this project may identify novel targets for therapeutic intervention to inhibit cell senescence and delay aging. This, in turn could help mitigate the effects of aging and age-related morbidities in a rapidly aging Canadian population.