胸腺瘤相关重症肌无力患者 T 细胞中 cFLIP 的过表达。
cFLIP overexpression in T cells in thymoma-associated myasthenia gravis.
机构信息
Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg Mannheim, Germany.
Department of Neurology, University of Regensburg Regensburg, Germany.
出版信息
Ann Clin Transl Neurol. 2015 Sep;2(9):894-905. doi: 10.1002/acn3.210. Epub 2015 Jul 22.
OBJECTIVE
The capacity of thymomas to generate mature CD4+ effector T cells from immature precursors inside the tumor and export them to the blood is associated with thymoma-associated myasthenia gravis (TAMG). Why TAMG(+) thymomas generate and export more mature CD4+ T cells than MG(-) thymomas is unknown.
METHODS
Unfixed thymoma tissue, thymocytes derived thereof, peripheral blood mononuclear cells (PBMCs), T-cell subsets and B cells were analysed using qRT-PCR and western blotting. Survival of PBMCs was measured by MTT assay. FAS-mediated apoptosis in PBMCs was quantified by flow cytometry. NF-κB in PBMCs was inhibited by the NF-κB-Inhibitor, EF24 prior to FAS-Ligand (FASLG) treatment for apoptosis induction.
RESULTS
Expression levels of the apoptosis inhibitor cellular FLICE-like inhibitory protein (c-FLIP) in blood T cells and intratumorous thymocytes were higher in TAMG(+) than in MG(-) thymomas and non-neoplastic thymic remnants. Thymocytes and PBMCs of TAMG patients showed nuclear NF-κB accumulation and apoptosis resistance to FASLG stimulation that was sensitive to NF-κB blockade. Thymoma removal reduced cFLIP expression in PBMCs.
INTERPRETATION
We conclude that thymomas induce cFLIP overexpression in thymocytes and their progeny, blood T cells. We suggest that the stronger cFLIP overexpression in TAMG(+) compared to MG(-) thymomas allows for the more efficient generation of mature CD4+ T cells in TAMG(+) thymomas. cFLIP overexpression in thymocytes and exported CD4+ T cells of patients with TAMG might contribute to the pathogenesis of TAMG by impairing central and peripheral T-cell tolerance.
目的
胸腺瘤内不成熟前体在肿瘤内产生成熟 CD4+效应 T 细胞并输出到血液中的能力与胸腺瘤相关重症肌无力（TAMG）有关。为什么 TAMG(+)胸腺瘤比 MG(-)胸腺瘤产生和输出更多成熟的 CD4+T 细胞尚不清楚。
方法
使用 qRT-PCR 和 Western blot 分析固定的胸腺瘤组织、从中衍生的胸腺细胞、外周血单核细胞 (PBMC)、T 细胞亚群和 B 细胞。通过 MTT 测定法测量 PBMC 的存活率。通过流式细胞术定量测定 PBMC 中 FAS 介导的细胞凋亡。在 FASL（FAS 配体）诱导凋亡之前，用 NF-κB 抑制剂 NF-κB-Inhibitor，EF24 抑制 PBMC 中的 NF-κB。
结果
TAMG(+)胸腺瘤和非肿瘤性胸腺残体中，T 细胞和肿瘤内胸腺细胞中凋亡抑制剂细胞 FLICE 样抑制蛋白 (c-FLIP) 的表达水平高于 MG(-)胸腺瘤。TAMG 患者的胸腺细胞和 PBMC 显示核 NF-κB 积累，并且对 FASLG 刺激的细胞凋亡具有抗性，这种抗性对 NF-κB 阻断敏感。胸腺瘤切除减少了 PBMC 中的 cFLIP 表达。
结论
我们得出结论，胸腺瘤诱导胸腺细胞及其祖细胞、血液 T 细胞中 cFLIP 的过度表达。我们认为，与 MG(-)胸腺瘤相比，TAMG(+)胸腺瘤中更强的 cFLIP 过表达允许在 TAMG(+)胸腺瘤中更有效地产生成熟的 CD4+T 细胞。TAMG 患者的胸腺细胞和输出的 CD4+T 细胞中 cFLIP 的过度表达可能通过损害中枢和外周 T 细胞耐受而有助于 TAMG 的发病机制。
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