Donor organ-specific exosome platform for monitoring transplant organ rejection

描述（由申请人提供）：器官移植显著提高了患者的生存率和生活质量。然而，大多数患者患有与移植器官相关的并发症，例如急性和慢性排斥反应、过度免疫抑制和感染。目前，迫切需要简单、时间敏感、可靠和非侵入性的方法来监测移植患者的供体器官排斥/损伤。这样的生物标志物测定将使得能够进行早期干预、免疫抑制滴定，并且因此改善患者发病率和死亡率。这个问题与心脏领域尤其相关 和肺移植，其中迄今为止没有血清生物标志物测定来监测移植的心脏或肺的状态。外来体是由许多组织释放到体液（包括血液和尿液）中的细胞外微泡。它们代表了稳定的和组织特异性的蛋白质组和RNA特征谱，反映了它们的组织的条件状态， 起源我们的小组已经表明，组织特异性外泌体谱及其RNA特征在健康与损伤/病理条件下是不同的。因此，了解组织特异性 来自体液的外泌体谱有望用作其来源组织状态的“液体活组织检查”。迄今为止，没有研究在监测移植器官状态的背景下评估外泌体平台，或者已经显示移植器官是否将供体组织特异性外泌体释放到受体血液/体液中。据我们所知，我们是第一个报告移植的器官组织释放稳定和可检测的供体特异性外泌体池到受体血液/体液中的人。鉴于新概念的这种证明，我们假设供体器官外泌体平台基于移植器官的条件状态-维持与排斥/损伤是不同的。因此，移植器官特异性外泌体及其相关RNA货物的分离和表征，沿着其差异表达与临床病理学数据的相关性，将为开发新的、时间敏感的、准确的和非侵入性的生物标志物测定以监测移植器官排斥/损伤奠定基础。由于迄今为止还没有研究表征移植器官特异性外泌体池，因此我们建议在两种体内移植模型中研究这种新概念：（1）在耐受与排斥的受控设置下建立的异位心脏移植小鼠模型，和（2）临床设置中的人活体供体肾移植。在这两种情况下，我们将表征移植器官特异性外泌体池及其在健康与排斥/损伤条件下的RNA特征，以发现与器官损伤相关的不同谱，这些谱将作为移植器官特异性外泌体池的平台。 开发新的生物标志物测定以监测移植排斥/损伤。

DESCRIPTION (provided by applicant): Organ transplantation significantly improves patient survival and quality of life. However, majority of patients suffer from complications associated with the transplanted organ, such as acute and chronic rejection, over- immunosuppression, and infection. Currently, there is a critical need for simple, time-sensitive, reliable, and non-invasive methods to monitor transplant patients for donor organ rejection/ injury. Such a biomarker assay would enable early intervention, immunosuppression titration, and thus improve patient morbidity and mortality. This problem is especially relevant to the fields of heart and lung transplantation, where to this date there is no serum biomarker assay to monitor the status of the transplanted heart or lung. Exosomes are extracellular microvesicles released by many tissues into bodily fluids, including blood and urine. They represent stable and tissue-specific proteomic and RNA signature profiles that reflect the conditional state of their tissue of origin. Our group has shown that tissue specific exosome profiles and their RNA signatures are distinct in conditions of health versus injury/ pathology. Therefore, understanding tissue specific exosome profiles from bodily fluids has promise to serve as a "liquid biopsy" of the status of their tissue of origin. No study, to date, has assessed the exosome platform in the context of monitoring transplant organ status, or has shown whether transplant organ releases donor tissue-specific exosomes into the recipient blood/ bodily fluids. To our knowledge, we are the first to report that transplanted organ tissue releases a stable and detectable pool of donor-specific exosomes into the recipient blood/ bodily fluids. Given this proof of novel concept, we hypothesize that donor organ exosome platforms are distinct based on the conditional state of the transplanted organ - maintenance versus rejection/ injury. Therefore, isolation and characterization of transplant organ-specific exosomes and their associated RNA cargo, along with correlation of their differential expression with clinicopathologic data would lay the groundwork for development of a novel, time-sensitive, accurate, and non- invasive biomarker assay to monitor for transplant organ rejection/ injury. Since no study to date has characterized transplant organ specific exosome pools, we propose to investigate this novel concept in two in vivo transplant models: (1) established mouse model of heterotopic heart transplantation under controlled settings of tolerance versus rejection, and; (2) human living donor renal transplantation in the clinical setting. In both settings we will characterize transplant organ specific exosome pools and their RNA signatures in conditions of health versus rejection/ injury to discover distinct profiles associated with organ injury that would serve as the platform for the development of novel biomarker assay to monitor transplant rejection/ injury.