Department of Surgery, The Methodist Hospital and The Methodist Hospital Research Institute, Houston, Texas, USA.
J Heart Lung Transplant. 2012 Jan;31(1):73-84. doi: 10.1016/j.healun.2011.01.715. Epub 2011 Apr 16.
Dendritic cells are professional antigen presenting cells that perform antigen processing and antigen presentation functions and rely on the proper functioning and distribution of the endoplasmic reticulum (ER) and Golgi apparatus and of vesicular trafficking pathways. We previously developed a model system to study the mechanisms governing inhibition of chronic rejection of heart allografts.
Heterotopic cardiac transplants were placed intra-abdominally and the major histocompatibility class (MHC) class I allochimeric molecule, [α1h1/u]-RT1.Aa, which contains donor-type (Wistar Furth, WF; RT1u) immunogenic epitopes displayed on recipient-type (ACI, RT1a) sequences, was delivered by portal vein to the recipients of heterotopic hearts. Dendritic cells were isolated from the recipient bone marrow at 1 and 3 days after transplantation and were immunostained or processed for Western blotting with anti-RhoB, translationally controlled tumor protein (TCTP), Sprouty-related (Spred1) protein, ER, and Golgi antibodies.
Western blotting analyses showed the downregulation of RhoB GTPase, TCTP, and Spred1 in dendritic cells isolated from allochimeric molecule-treated rats. Immunostaining showed that in these cells, Spred 1 was shifted to the base of cellular processes, Rho B formed nonvesicular band in the cell equator, and TCTP was highly enriched in the cell nucleus. The Golgi apparatus was drastically reduced in size and formed a tiny nonvesicular aggregate, and the ER partially lost vesicular appearance.
The function of allochimeric molecule in the abrogation of heart allograft rejection may rely on the downregulation of RhoB pathway components that regulate the structure and function of the ER/Golgi/vesicular trafficking pathways involved in antigen processing and presentation by dendritic cells.
树突状细胞是专业的抗原呈递细胞，具有抗原加工和呈递功能，依赖于内质网（ER）和高尔基体以及囊泡运输途径的正常功能和分布。我们之前开发了一种模型系统来研究控制心脏同种异体移植物慢性排斥反应的机制。
异位心脏移植放置在腹腔内，主要组织相容性（MHC）I 类同种异体分子 [α1h1/u]-RT1.Aa，其中包含供体型（Wistar Furth，WF；RT1u）免疫原性表位，显示在受体型（ACI，RT1a）序列上，通过门静脉递送到异位心脏的接受者。在移植后 1 天和 3 天从受者骨髓中分离出树突状细胞，并进行免疫染色或 Western 印迹分析，用抗 RhoB、翻译控制肿瘤蛋白（TCTP）、Spred 相关（Spred1）蛋白、ER 和高尔基体抗体进行处理。
Western 印迹分析显示，从同种异体分子处理的大鼠分离的树突状细胞中 RhoB GTPase、TCTP 和 Spred1 下调。免疫染色显示，在这些细胞中，Spred1 转移到细胞突起的基部，RhoB 在细胞赤道形成非囊泡带，TCTP 在细胞核中高度富集。高尔基体大小明显缩小，形成一个微小的非囊泡聚集物，内质网部分失去囊泡外观。
同种异体分子在阻断心脏同种异体移植物排斥反应中的作用可能依赖于 RhoB 途径成分的下调，这些成分调节参与抗原加工和呈递的树突状细胞中 ER/Golgi/囊泡运输途径的结构和功能。
