Zhao Wanhong, Zhang Yilin, Zhang Pengyu, Yang Juan, Zhang Longjin, He Aili, Zhang Wanggang, Hideto Tamura
Department of Hematology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710004, China.
Department of Hematology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710004, China.
Immunol Lett. 2017 Mar;183:44-51. doi: 10.1016/j.imlet.2017.01.016. Epub 2017 Jan 30.
Programmed death 1 (PD-1) has been reported to be associated with aberrant regulation of T cells activation in aplastic anemia (AA). However, the connection between PD-1 expression status and AA needs to be further explored. The aim of this study is to investigate PD-1 expression status on T cells in AA patients and to explore the effect of PD-1 on apoptosis of T cells and BMHSCs. The concentration of platelet, lymphocyte and hemoglobin in peripheral blood of AA patients and healthy volunteers was detected by automatic blood-counter system. Mononuclear cells (MNCs) of peripheral blood and marrow were isolated from AA patients and healthy volunteers. PD-1 expression level on CD3+, CD4+, CD8+, CD4+CD25+FOXP3+ T cells and bone marrow hematopoietic stem cells (BMHSCs) and B7-H1 expression level on peripheral blood mononuclear cells (PBMCs) and BMHSCs were detected by flow cytometry (FCM). Cell apoptosis on T cells and BMHSCs was also detected by FCM. PD-1, B7-H1, Bax and Bcl-2 mRNA expression levels on T cells of peripheral blood were detected by real-time PCR. MNCs from healthy volunteers were treated with ammonium pyrrolidine dithiocarbamate (PDTC) to block the nuclear factor (NF)-кB pathway. Our results showed that in AA patients, T cells had high levels of PD-1 expression and apoptosis rate. In BMHSCs, apoptosis rate was also higher than healthy volunteers. The expression of PD-1 on T cells was correlated with lymphocyte count and hemoglobin level. PD-1 was highly expressed on CD4+CD25+FOXP3+ T cells of AA patients and PD-1 expression was negatively correlated with the percentage of CD4+CD25+FOXP3+ T cells in AA patients. B7-H1, the ligand of PD-1, was also highly expressed on T cells, B cells, PBMCs and BMHSCs. When the NF-κB pathway was blocked by PDTC, the apoptosis of T cells and BMHSCs was reduced in a dose-dependent manner and PD-1 expression was also decreased in a dose-dependent manner. In conclusion, PD-1 was up-regulated in T cells in AA patients compared with healthy volunteers. The NF-κB pathway participated in the process of apoptosis of CD4+CD25+FOXP3+ T cells and BMHSCs induced by PD-1 in AA patients.
据报道，程序性死亡1（PD-1）与再生障碍性贫血（AA）中T细胞活化的异常调节有关。然而，PD-1表达状态与AA之间的联系仍需进一步探索。本研究旨在调查AA患者T细胞上PD-1的表达状态，并探讨PD-1对T细胞和骨髓造血干细胞（BMHSCs）凋亡的影响。采用自动血液计数系统检测AA患者和健康志愿者外周血中血小板、淋巴细胞和血红蛋白的浓度。从AA患者和健康志愿者中分离外周血和骨髓的单核细胞（MNCs）。采用流式细胞术（FCM）检测CD3+、CD4+、CD8+、CD4+CD25+FOXP3+ T细胞和骨髓造血干细胞（BMHSCs）上PD-1的表达水平，以及外周血单核细胞（PBMCs）和BMHSCs上B7-H1的表达水平。也通过FCM检测T细胞和BMHSCs的细胞凋亡。采用实时PCR检测外周血T细胞上PD-1、B7-H1、Bax和Bcl-2 mRNA的表达水平。用吡咯烷二硫代氨基甲酸铵（PDTC）处理健康志愿者的MNCs以阻断核因子（NF）-κB途径。我们的结果显示，在AA患者中，T细胞具有高水平的PD-1表达和凋亡率。在BMHSCs中，凋亡率也高于健康志愿者。T细胞上PD-1的表达与淋巴细胞计数和血红蛋白水平相关。AA患者的CD4+CD25+FOXP3+ T细胞上PD-1高表达，且AA患者中PD-1表达与CD4+CD25+FOXP3+ T细胞百分比呈负相关。PD-1的配体B7-H1在T细胞、B细胞、PBMCs和BMHSCs上也高表达。当用PDTC阻断NF-κB途径时，T细胞和BMHSCs的凋亡以剂量依赖的方式减少，PD-1表达也以剂量依赖的方式降低。总之，与健康志愿者相比，AA患者T细胞中PD-1上调。NF-κB途径参与了AA患者中PD-1诱导的CD4+CD25+FOXP3+ T细胞和BMHSCs的凋亡过程。
