Extracellular vesicles in cellular aging

细胞代谢功能和复制能力的进行性下降是衰老的标志，也是人类寿命的核心决定因素。这些变化在所有细胞类型和物种中都高度保守，并且是可修改的：在疾病中加速，但可以重新编程以延缓衰老和延长寿命。我们和其他人已经证明，通过向外的膜泡化(外体途径)释放的大EV会诱导衰老。相反，我们的初步数据表明，来自内体通路的小型EV保留了功能和复制能力。这项研究计划探索EVS在衰老过程中细胞间通信中的作用，目的是发现新的方法来优化整个生命过程中的细胞衰老。在接下来的五年里，我们将检验这一特定的假设，即衰老细胞经历表型转变，从释放内体来源的EV来维持细胞功能，到释放外体来源的EV来诱导二次衰老和细胞进行性衰老。我们将集中在三个研究问题上：1.衰老细胞是否经历了从内体EV分泌到外体EV分泌的转变？我们将检查复制性衰老、应激诱导的早衰和早衰症患者的成纤维细胞模型，并比较EV释放到细胞外环境的表型。我们将量化EV水平并评估单个EV亚群的变化。我们将把特定EV亚群(外体、ARRDC1介导的微泡[小胞体]和微泡[大胞体])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.EVS是否调节靶细胞中的细胞衰老途径。我们将评估EV亚群对靶细胞中细胞衰老途径的影响。我们将测试来自衰老人群的EV是否会诱导二次衰老，以及来自年轻/健康细胞的EV是否可以抑制衰老。我们将通过蛋白质组学的方法寻找EV信号通路的候选蛋白。3.衰老细胞能否被重新编程为内体EV分泌，从而延缓二次衰老？最后，我们将测试是否有可能对细胞进行重新编程，以保持它们分泌内体EV的能力。我们将测试3种方法。1)诱导内体EV的形成，2)抑制外体EV的形成，以及3)通过靶向一个新的分子开关(二酰甘油激酶？)将EV的形成从外体重定向到内体途径。最近与斯蒂芬·吉博士合作确定的。我们建议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，该项目可能会确定治疗干预的新靶点，以抑制细胞衰老和延缓衰老。这反过来又有助于减轻老龄化和与年龄相关的疾病对快速老龄化的加拿大人口的影响。

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.