Requirements and mechanisms of alloantigen-induced cardiac allograft survival by cDC1s

项目总结/摘要 心脏移植是目前晚期心力衰竭的唯一治疗方法，因此， 全球进行的移植手术继续增加。手术技术的进步， 免疫抑制剂可以明显改善患者的生存率，但在几年后就不能这么说了。 移植免疫介导的病理如慢性同种异体移植物血管病变导致移植物衰竭， 长期使用免疫抑制药物导致的显著发病率，包括肾功能不全、糖尿病， 和恶性肿瘤，继续由患者经历。因此，改善策略，以促进生存 心脏移植是必要的 大量的研究试图确定负责心脏同种异体移植排斥反应的细胞因子， 宽容在排斥反应的背景下，适应性免疫反应已成为主导作用，特别是 CD 4+和CD 8 + T细胞。重要的是，T细胞不是单独的表演者，而是需要由 抗原呈递细胞，主要是树突状细胞（DC）。一旦被认为是一个同质的人口， 现在被认为是其独特的个体发育和功能的作用，决定了DC子集的身份。 常规DC 1细胞（cDC 1）是免疫应答的强有力介质，并且已被证明是 对促进中枢耐受性至关重要。然而，还没有关于cDC 1在实体器官中的亚群特异性作用的工作。 移植已经进行，我们对cDC 1在外周耐受中的理解仍停留在其 婴儿期。重要的是，我的初步数据暗示cDC 1在供体诱导的耐受化策略中是必要的。 导致心脏移植物长期存活。 利用输注供体抗原和共刺激阻断（CoB）的耐受策略产生长期的免疫耐受。 小鼠和非人灵长类动物模型中的心脏移植物存活率，尽管对暴露于 供体同种抗原影响耐受诱导。这一建议假设，在捐助国诱导的 在免疫耐受策略中，cDC 1亚群是促进外周免疫应答所必需的。 通过处理同种异体抗原、调节 表面标记表达和代谢转录重编程。这一假设将得到检验 使用cDC 1缺失和异位心脏移植的小鼠模型以及功能性（触诊， 超声心动图）和细胞（流式细胞术，组织学）分析。此外，单细胞转录组学 在CoB存在下体内同种异体和同种异体输注后，结合体外实验， 有助于揭示促进致耐受性同种异体特异性应答cDC 1特异性编程。因此，拟议的 研究将确定增强免疫耐受性和改善心脏移植物存活的靶向途径。

PROJECT SUMMARY/ABSTRACT Heart transplantation is currently the only treatment for advanced stage heart failure and as such, the volume of transplants performed globally continues to increase. Advances in surgical technique and available immunosuppression have improved patient survival acutely, however the same cannot be said years after transplantation. Immune mediated pathologies such as chronic allograft vasculopathy result in graft failure and significant morbidity from prolonged use of immunosuppressant medication including renal dysfunction, diabetes, and malignancy, continue to be experienced by patients. Therefore, improved strategies to promote survival of the cardiac allograft are necessary. A great deal of research has sought to identify the cellular actors responsible for cardiac allograft rejection and tolerance. In the setting of rejection, the adaptive immune response has emerged in a leading role, specifically CD4+ and CD8+ T cells. Importantly, T cells are not solo performers but instead require instruction provided by antigen presenting cells, predominantly dendritic cells (DCs). Once considered a homogenous population, DCs are now recognized for their distinct ontogeny and functional roles which determine DC subset identity. Conventional DC 1 cells (cDC1s) are powerful mediators of the immune response and have been shown to be critical for the promotion of central tolerance. Yet no work on the subset specific role of cDC1s in solid organ transplantation has been performed and our understanding of cDC1s in peripheral tolerance remains in its infancy. Importantly, my preliminary data implicate cDC1s as necessary in donor-induced tolerization strategies that result in long term cardiac allograft survival. Tolerization strategies utilizing infused donor antigen and costimulation blockade (CoB) produce long term cardiac allograft survival in murine and nonhuman primate models, though little is known as to how exposure of donor alloantigen influences tolerance induction. This proposal hypothesizes that during a donor-induced tolerance strategy, the cDC1 subset is necessary to promote peripheral immunological hyporesponsiveness towards cardiac allografts through processing of alloantigen, modulation of surface marker expression, and metabolic transcriptional reprogramming. This hypothesis will be tested using mouse models of cDC1 deletion and heterotopic heart transplantation alongside functional (palpation, echocardiography) and cellular (flow cytometry, histology) analysis. Additionally, single-cell transcriptomics of splenic DCs after in vivo allo- and iso- infusion in the presence of CoB coupled with in vitro experimentation will help unveil cDC1 specific programming that promote a tolerogenic allospecific response. Thus, the proposed studies will identify targetable pathways to enhance immunologic tolerance and improve cardiac allograft survival.