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存活率和生活质量。然而，大多数患者都患有与移植器官相关的并发症，如急性和慢性排斥反应、过度免疫抑制和感染。目前，迫切需要一种简单、及时、可靠和非侵入性的方法来监测移植患者的供体器官排斥反应/损伤。这样的生物标志物检测将使早期干预、免疫抑制滴定成为可能，从而改善患者的发病率和死亡率。这个问题与心脏领域特别相关。 和肺移植，到目前为止还没有血清生物标记物分析来监测移植的心脏或肺的状态。胞外体是许多组织释放到体液中的细胞外微囊，包括血液和尿液。它们代表稳定的和组织特异性的蛋白质组和RNA签名图谱，反映其组织的条件状态 起源。我们的团队已经表明，在健康和损伤/病理条件下，组织特异的外切体特征及其RNA签名是不同的。因此，了解组织特异性 从体液中提取的外周体谱有望成为对其起源组织状态的“液体活检”。到目前为止，还没有研究在监测移植器官状态的背景下评估外切体平台，也没有研究表明移植器官是否将供体组织特异性的外切体释放到受者的血液/体液中。据我们所知，我们是第一个报告移植的器官组织向受者的血液/体液中释放稳定且可检测到的供体特异性外切体池的人。鉴于这一新概念的证明，我们假设，基于移植器官的条件状态-维持与排斥/损伤-供体器官外体平台是不同的。因此，分离和鉴定移植器官特异性外切体及其相关的RNA载体，以及它们的差异表达与临床病理数据的相关性，将为开发一种新的、时间敏感、准确和非侵入性的监测移植器官排斥反应/损伤的生物标志物奠定基础。由于到目前为止还没有研究确定移植器官特异性外切体池的特征，我们建议在两个体内移植模型中探讨这一新概念：(1)建立耐受和排斥控制环境下的异位小鼠心脏移植模型；(2)临床环境下的人类活体供肾移植。在这两种情况下，我们将表征移植器官特定的外切体池及其在健康条件下与排斥/损伤条件下的RNA签名，以发现与器官损伤相关的不同特征，这将作为 用于监测移植排斥反应/损伤的新型生物标记物的开发。

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.