Geng Y J, Wu Q, Muszynski M, Hansson G K, Libby P
Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Arterioscler Thromb Vasc Biol. 1996 Jan;16(1):19-27. doi: 10.1161/01.atv.16.1.19.
Recent studies have documented evidence for the death of smooth muscle cells (SMCs) within advanced human atheroma. These lesions contain macrophages and T lymphocytes in addition to SMCs. We therefore investigated whether interferon-gamma (IFN-gamma), a cytokine secreted by T lymphocytes, or interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha), two cytokines characteristically produced by activated macrophages, can trigger apoptosis of vascular SMCs. Simultaneous treatment with IFN-gamma and TNF-alpha and/or IL-1 beta but not with each cytokine alone promoted death of human and rat SMCs. Exposure for 48 hours to a combination of IFN-gamma (400 U/mL), TNF-alpha (400 U/mL), and IL-1 beta (100 U/mL) significantly (P < .001) increased the accumulation of oligonucleosomes comprising DNA fragments and histones in human SMCs. Electrophoresis of genomic DNA showed internucleosomal fragments of genomic DNA isolated from the cytokine-cotreated SMCs of both humans and rats. These cells exhibited morphological changes typical of apoptosis, including cell shrinkage, membrane blebbing, chromatin condensation, and nuclear fragmentation. In situ 3' end labeling of DNA fragments with terminal transferase confirmed the fragmentation of genomic DNA in these cells. Simultaneous treatment with IFN-gamma and TNF-alpha or IL-1 beta induced elaboration of nitrite, an end product of nitric oxide, in rat but not human SMCs. NG-monomethyl-L-arginine inhibited nitrite accumulation and also partly blocked cytokine-induced apoptosis of rat SMCs but had little effect on human SMCs, suggesting operation of both nitric oxide-dependent and -independent mechanisms for cytokine-induced apoptosis in vascular SMCs. Production of immune cytokines by vascular cells and/or infiltrating leukocytes may regulate apoptotic death of SMCs during atherogenesis.
最近的研究记录了晚期人类动脉粥样硬化中平滑肌细胞（SMC）死亡的证据。这些病变除了含有SMC外，还包含巨噬细胞和T淋巴细胞。因此，我们研究了T淋巴细胞分泌的细胞因子γ干扰素（IFN-γ），或活化巨噬细胞特有的两种细胞因子白细胞介素-1β（IL-1β）和肿瘤坏死因子-α（TNF-α）是否能触发血管SMC的凋亡。IFN-γ与TNF-α和/或IL-1β同时处理可促进人和大鼠SMC的死亡，而单独使用每种细胞因子则无此作用。将人SMC暴露于IFN-γ（400 U/mL）、TNF-α（400 U/mL）和IL-1β（100 U/mL）的组合中48小时，显著（P <.001）增加了由DNA片段和组蛋白组成的寡核小体的积累。基因组DNA电泳显示，从人和大鼠经细胞因子联合处理的SMC中分离出的基因组DNA存在核小体间片段。这些细胞表现出典型的凋亡形态变化，包括细胞收缩、膜泡化、染色质浓缩和核碎片化。用末端转移酶对DNA片段进行原位3'末端标记证实了这些细胞中基因组DNA的碎片化。IFN-γ与TNF-α或IL-1β同时处理可诱导大鼠SMC中一氧化氮的终产物亚硝酸盐的生成，而人SMC中则无此现象。NG-单甲基-L-精氨酸抑制亚硝酸盐积累，也部分阻断细胞因子诱导的大鼠SMC凋亡，但对人SMC影响不大，提示血管SMC中细胞因子诱导凋亡存在一氧化氮依赖性和非依赖性机制。血管细胞和/或浸润白细胞产生的免疫细胞因子可能在动脉粥样硬化形成过程中调节SMC的凋亡死亡。
