Fukuchi K I, Kunkel D D, Schwartzkroin P A, Kamino K, Ogburn C E, Furlong C E, Martin G M
Department of Pathology, University of Washington, Seattle 98195.
Exp Neurol. 1994 Jun;127(2):253-64. doi: 10.1006/exnr.1994.1101.
The role of beta-amyloid protein and its precursor protein is a central question in the pathogenesis of Alzheimer's disease. We have established several transformants from a mouse embryonic carcinoma cell line, which overproduce a C-terminal region of the beta-amyloid precursor protein from the integrated DNA constructs. These stable transformants degenerated to varying extents when undergoing neural differentiation mediated by retinoic acid. To test the neurotoxicity and the amyloidogenicity of the transgene product and its proteolytic derivatives in vivo, two stable transformants were neuronally differentiated and transplanted into the hippocampal regions of syngeneic mice. Similarly, either a nontransformant or a transformant bearing a cDNA construct for yeast major apurinic endonuclease was transplanted to the contralateral regions of the same mice. Three weeks after transplantation, grafts were identified around needle tracts or in hippocampal regions. The regions where transformants overproducing the C-terminal region were grafted were highly reactive to antibodies raised against beta-amyloid protein and its precursor protein, in contrast to the contralateral regions. At 2 and 5 months after neurotransplantation, remarkable distortion and shrinkage characterized the hippocampus on the sides injected with the transformants overproducing the C-terminal region. This shrinkage was associated particularly with a loss of the hippocampal granule cells. beta-Amyloid protein immunoreactive granular deposits in the neuropil were also found in the same sides. Hippocampal blood vessel walls were also stained with the antibodies. These walls were surrounded by astrocytic processes, suggesting involvement of astroglial cells in vascular deposits of beta-amyloid protein. The results are consistent with the hypothesis that the C-terminal region or its derivatives are neurotoxic and amyloidogenic.
β-淀粉样蛋白及其前体蛋白的作用是阿尔茨海默病发病机制中的核心问题。我们从一种小鼠胚胎癌细胞系中建立了几种转化体，这些转化体从整合的DNA构建体中过量产生β-淀粉样前体蛋白的C末端区域。当这些稳定的转化体在视黄酸介导的神经分化过程中，会在不同程度上发生退化。为了在体内测试转基因产物及其蛋白水解衍生物的神经毒性和淀粉样变性，将两种稳定的转化体进行神经分化后移植到同基因小鼠的海马区。同样，将一个非转化体或携带酵母主要脱嘌呤内切核酸酶cDNA构建体的转化体移植到同一只小鼠的对侧区域。移植三周后，在针道周围或海马区发现了移植物。与对侧区域相比，移植过量产生C末端区域的转化体的区域对针对β-淀粉样蛋白及其前体蛋白产生的抗体具有高度反应性。在神经移植后2个月和5个月时，注射过量产生C末端区域的转化体一侧的海马出现明显的变形和萎缩。这种萎缩尤其与海马颗粒细胞的丧失有关。在同一侧的神经毡中也发现了β-淀粉样蛋白免疫反应性颗粒沉积物。海马血管壁也被抗体染色。这些血管壁被星形胶质细胞突起包围，表明星形胶质细胞参与了β-淀粉样蛋白的血管沉积。结果与C末端区域或其衍生物具有神经毒性和淀粉样变性的假设一致。
