Sgonc R, Gruschwitz M S, Boeck G, Sepp N, Gruber J, Wick G
University of Innsbruck Medical School, Austria.
Arthritis Rheum. 2000 Nov;43(11):2550-62. doi: 10.1002/1529-0131(200011)43:11<2550::AID-ANR24>3.0.CO;2-H.
Apoptosis of endothelial cells is a key event in the pathogenesis of systemic sclerosis (SSc). The aim of the present study was to analyze in vitro the mechanism causing endothelial cell apoptosis in SSc.
Human dermal microvascular endothelial cells (HDMEC) or human umbilical vein endothelial cells (HUVEC) were cultured with native or heat-inactivated serum from SSc patients or controls with or without interleukin-2-activated natural killer (NK) cells or peripheral blood mononuclear cells. SSc and control sera were tested for the presence or absence, respectively, of anti-endothelial cell antibodies (AECA) by indirect immunofluorescence. Apoptosis was detected by the TUNEL technique.
Native sera alone had no effect. Apoptosis induction was observed on HDMEC, but not on HUVEC, in the presence of AECA-positive SSc sera and activated NK cells, and could be inhibited by an anti-Fas ligand antibody. Inhibition of the perforin/granzyme pathway with concanamycin A had no effect on apoptosis induction in this in vitro model. Immunofluorescence analysis of cryosections from SSc skin showed Fas (CD95) expression by endothelial cells, supporting the in vitro findings.
The results suggest that endothelial cell apoptosis in SSc is induced by antibody-dependent cell-mediated cytotoxicity via the Fas pathway. These data not only provide insight into the pathogenesis of SSc, but also may open new ways to rational therapy for this disease.
内皮细胞凋亡是系统性硬化症（SSc）发病机制中的关键事件。本研究旨在体外分析SSc中导致内皮细胞凋亡的机制。
用人真皮微血管内皮细胞（HDMEC）或人脐静脉内皮细胞（HUVEC）与来自SSc患者或对照的天然或热灭活血清一起培养，同时加入或不加入白细胞介素-2激活的自然杀伤（NK）细胞或外周血单个核细胞。通过间接免疫荧光分别检测SSc和对照血清中抗内皮细胞抗体（AECA）的有无。采用TUNEL技术检测细胞凋亡。
单独的天然血清无作用。在存在AECA阳性的SSc血清和激活的NK细胞时，HDMEC出现凋亡诱导现象，而HUVEC未出现，且抗Fas配体抗体可抑制这种凋亡。在该体外模型中，用 concanamycin A抑制穿孔素/颗粒酶途径对凋亡诱导无影响。对SSc皮肤冰冻切片的免疫荧光分析显示内皮细胞表达Fas（CD95），支持体外研究结果。
结果表明，SSc中的内皮细胞凋亡是由抗体依赖性细胞介导的细胞毒性通过Fas途径诱导的。这些数据不仅有助于深入了解SSc的发病机制，还可能为该病的合理治疗开辟新途径。
