Plasmacytoid Dendritic Cell microRNAS in Transplantation

7.项目总结 同种异体肝移植一般耐受性良好，而其他实体器官移植，如小肠、心脏、 与肝脏同时移植的肾脏显示出更好的移植结果。然而，这些机制 潜在的“肝脏耐受性”尚不清楚。肝浆细胞样树突状细胞p(DC) 与淋巴组织中的DC相比，其刺激免疫反应的能力减弱。 此外，DC子集之间的功能差异，包括(P)DC和常规(C)DC，已经被 定义为，假设不成熟的PDC天生会抑制免疫反应，并具有耐受性。 事实上，多项研究表明，PDC在耐受性的产生中发挥着独特而重要的作用。 然而，PDC致耐受特性的机制仍不清楚。最近我们 确定miR-181家族中的六个成员在肝脏中都显著增加 PDC与肝脏CDC的比较。此外，我们还发现肝PDC显著延长了同种异体实体器官移植的时间。 在没有miR-181a的情况下，生存和这一提高生存的能力被废除。我们提案的总体目标是 1)确定miR-181表达的PDC改变免疫系统以改善免疫系统的机制 同种异体实体器官移植的存活及2)利用表达miR-181的PDC延长移植物的能力 以产生一种治疗方法来延长同种异体移植物的存活时间。在我们的第一个具体目标中，我们将检验这一假设 表达miR-181的PDC可以改变免疫反应以提高移植物的存活率。一个 完全分析miR-181+和miR-181-/-PDC移植后的免疫反应，使用 尖端的CyTOF技术，将被表演。MiR-181表达的PDC的mRNA靶点，以及 生物功能，将被确定。此外，还将确定表达miR-181的PDC是否延长 同种异体移植物通过顺式或反式功能存活。在我们的第二个具体目标中，我们将测试以下假设 (过度)表达miR-181a可延长移植物存活时间。由于PDC存在于如此有限 肝脏PDC作为一种细胞治疗手段的研究进展有限。在这个目标中，我们将研究是否 在较丰富的骨髓来源的DC中高表达miR-181可以延长移植物存活时间。结果 来自这些高度新颖的研究将导致改善结果，并提高移植的生活质量 接受者和他们的家人。

7. Project Summary Liver allografts are generally well tolerated, and other solid organ allografts, such as the small intestine, heart, and kidney, transplanted concurrently with livers show improved graft outcomes. However, the mechanisms underlying “hepatic tolerance” have yet to be elucidated. Hepatic plasmacytoid dendritic cells p(DC) have been shown to have diminished ability to stimulate an immune response as compared with DC in lymphoid tissue. Further, functional differences between DC subsets, including (p)DC and conventional (c)DC, have been defined, with the hypothesis that immature pDC inherently dampen an immune response and are tolerogenic. Indeed, multiple studies show that pDC play a unique and important role in the generation of tolerance. However, the mechanism responsible for the tolerogenic properties of pDC remains elusive. Recently we determined that six members of the miR-181 family of microRNAs were all significantly increased in hepatic pDC as compared to hepatic cDC. Further we show that hepatic pDC significantly prolong solid organ allograft survival and this enhanced survival in abrogated in the absence of miR-181a. The overall goals of our proposal are: 1) to determine the mechanism by which miR-181-expressing pDC alters the immune system to improve the survival of solid organ allografts and 2) exploiting the graft prolonging capacity of miR-181-expressing pDC to generate a therapeutic to prolong allograft survival. In our first specific aim, we will test the hypothesis that miR-181-expressing pDC modifies the immune response towards enhanced graft survival. A complete profiling of the immune response after transplantation with miR-181+ and miR-181-/- pDC, using cutting-edge CyTOF technology, will be performed. The mRNA target of miR-181-expressing pDC, and biological function, will be determined. Further, it will be determined if miR-181-expressing pDC prolongs allograft survival by functioning in cis or trans. In our second specific aim we will test the hypothesis that (over)expression of miR-181a can prolong allograft survival. Since pDC are present in such limited numbers development of hepatic pDC as a cellular therapeutic is limited. In this Aim we will examine whether over-expression of miR-181 in the more plentiful bone marrow derived DC can prolong graft survival. Results from these highly novel studies will result in improved outcomes, and enhance the quality of life for transplant recipients, and their families.