Deininger Martin H, Fimmen Birte A, Thal Dietmar R, Schluesener Hermann J, Meyermann Richard
Institute of Brain Research, University of Tuebingen Medical School, D-72076 Tuebingen, Germany.
J Neurosci. 2002 Dec 15;22(24):10621-6. doi: 10.1523/JNEUROSCI.22-24-10621.2002.
Cerebrovascular pathology is common in Alzheimer's disease (AD) and is considered to contribute to cerebral malfunction. However, distinct antiangiogenic proteins that accumulate in AD brains have not yet been identified. Endostatin is a 20 kDa C-terminal fragment of collagen XVIII that, when added exogenously, inhibits endothelial proliferation and migration in vitro and angiogenesis and tumor growth in vivo by inducing apoptosis in endothelial cells. We produced a monoclonal antibody directed against endostatin and observed significantly more (p < 0.0001) immunoreactive cortical neurons in AD brains compared with age-matched neuropathologically unaltered controls. High numbers of extracellular and frequently perivascular endostatin deposits were detected in the cerebral hemispheres. Double-labeling experiments revealed colocalization of endostatin in amyloid-beta(1-40) (Abeta(1-40)), tau protein, and periodic acid-Schiff stain-positive plaques that were surrounded by focal gliosis. Western blotting revealed more 20 kDa endostatin in an AD patient compared with a control. In unstimulated SKNSH supernatants, endostatin was detected that increased predominantly after hypoxia in supernatants and cellular lysates. Abeta(1-40) (80 microg/ml) supplementation to SKNSH neurons for 24 hr completely abolished the release of endostatin. These data show that endostatin is released by neurons to accumulate in amyloid plaques in Alzheimer's disease. Induction by hypoxia and complete abrogation of endostatin release after Abeta(1-40) challenge reveals intricate interactions between the two proteins and opens new avenues for the development of novel treatment strategies of AD patients.
脑血管病变在阿尔茨海默病（AD）中很常见，被认为是导致脑功能障碍的原因之一。然而，尚未在AD脑内发现有明显积聚的抗血管生成蛋白。内皮抑素是胶原蛋白XVIII的一个20 kDa C末端片段，体外实验中，外源性添加内皮抑素可抑制内皮细胞增殖和迁移，体内实验中可通过诱导内皮细胞凋亡抑制血管生成和肿瘤生长。我们制备了一种针对内皮抑素的单克隆抗体，发现与年龄匹配且神经病理学未改变的对照组相比，AD脑内免疫反应性皮质神经元显著增多（p < 0.0001）。在大脑半球检测到大量细胞外且常见于血管周围的内皮抑素沉积物。双标记实验显示内皮抑素与β淀粉样蛋白（1-40）（Aβ（1-40））、tau蛋白以及被局灶性胶质增生包围的过碘酸-希夫染色阳性斑块共定位。蛋白质印迹法显示，与对照组相比，AD患者体内20 kDa的内皮抑素更多。在未受刺激的SKNSH细胞上清液中检测到内皮抑素，缺氧后上清液和细胞裂解物中的内皮抑素主要增加。向SKNSH神经元补充Aβ（1-40）（80 μg/ml）24小时后，内皮抑素的释放完全被消除。这些数据表明，在阿尔茨海默病中，内皮抑素由神经元释放并积聚在淀粉样斑块中。缺氧诱导以及Aβ（1-40）刺激后内皮抑素释放完全消除，揭示了这两种蛋白之间复杂的相互作用，并为AD患者新治疗策略的开发开辟了新途径。
