Lee Eui-Nam, Cho Hyun-Ju, Lee Choong-Hwan, Lee Daekyun, Chung Kwang Chul, Paik Seung R
Department of Biochemistry, College of Medicine, Inha University, Nam-Ku, Incheon 402-751, Korea.
Biochemistry. 2004 Mar 30;43(12):3704-15. doi: 10.1021/bi0356707.
Alpha-synuclein is a pathological component of Parkinson's disease by constituting the filamentous component of Lewy bodies. Phthalocyanine (Pc) effects on the amyloidosis of alpha-synuclein have been examined. The copper complex of phthalocyanine tetrasulfonate (PcTS-Cu(2+)) caused the self-oligomerization of alpha-synuclein while Pc-Cu(2+) did not affect the protein, indicating that introduction of the sulfonate groups was critical for the selective protein interaction. The PcTS-Cu(2+) interaction with alpha-synuclein has occurred predominantly at the N-terminal region of the protein with a K(d) of 0.83 microM apart from the hydrophobic NAC (non-Abeta component of Alzheimer's disease amyloid) segment. Phthalocyanine tetrasulfonate (PcTS) lacking the intercalated copper ion also showed a considerable affinity toward alpha-synuclein with a K(d) of 3.12 microM, and its binding site, on the other hand, was located at the acidic C-terminus. These mutually exclusive interactions between PcTS and PcTS-Cu(2+) toward alpha-synuclein resulted in distinctive features on the kinetics of protein aggregation, morphologies of the final aggregates, and their in vitro cytotoxicities. The PcTS actually suppressed the fibrous amyloid formation of alpha-synuclein, but it produced the chopped-wood-looking protein aggregates. The aggregates showed rather low toxicity (9.5%) on human neuroblastoma cells (SH-SY5Y). In fact, the PcTS was shown to effectively rescue the cell death of alpha-synuclein overexpressing cells caused by the lactacystin treatment as a proteasome inhibitor. The anti-aggregative and anti-amyloidogenic properties of PcTS were also demonstrated with alcohol dehydrogenase, glutathione S-transferase, and amyloid beta/A4 protein under their aggregative conditions. The PcTS-Cu(2+), on the other hand, promoted the protein aggregation of alpha-synuclein, which gave rise to the fibrillar protein aggregates whose cytotoxicity became significant to 35.8%. Taken together, the data provided in this study indicate that PcTS/PcTS-Cu(2+) could be considered as possible candidates for the development of therapeutic or prophylactic strategies against the alpha-synuclein-related neurodegenerative disorders.
α-突触核蛋白是帕金森病的一种病理成分，构成路易小体的丝状成分。已研究了酞菁（Pc）对α-突触核蛋白淀粉样变性的影响。四磺酸酞菁铜络合物（PcTS-Cu(2+)）导致α-突触核蛋白的自寡聚化，而Pc-Cu(2+)对该蛋白无影响，这表明磺酸基团的引入对于选择性蛋白质相互作用至关重要。PcTS-Cu(2+)与α-突触核蛋白的相互作用主要发生在该蛋白的N端区域，除了疏水性的NAC（阿尔茨海默病淀粉样蛋白的非Aβ成分）片段外，解离常数K(d)为0.83微摩尔。缺乏嵌入铜离子的四磺酸酞菁（PcTS）对α-突触核蛋白也表现出相当大的亲和力，解离常数K(d)为3.12微摩尔，而其结合位点位于酸性C端。PcTS和PcTS-Cu(2+)对α-突触核蛋白的这些相互排斥的相互作用导致了蛋白质聚集动力学、最终聚集体形态及其体外细胞毒性的独特特征。PcTS实际上抑制了α-突触核蛋白的纤维状淀粉样蛋白形成，但产生了看起来像碎木的蛋白质聚集体。这些聚集体对人神经母细胞瘤细胞（SH-SY5Y）显示出相当低的毒性（9.5%）。事实上，PcTS被证明能有效挽救由作为蛋白酶体抑制剂的乳胞素处理导致的α-突触核蛋白过表达细胞的死亡。在乙醇脱氢酶、谷胱甘肽S-转移酶和淀粉样β/A4蛋白的聚集条件下，也证明了PcTS的抗聚集和抗淀粉样生成特性。另一方面，PcTS-Cu(2+)促进了α-突触核蛋白的蛋白质聚集，产生了纤维状蛋白质聚集体，其细胞毒性显著增加至35.8%。综上所述，本研究提供的数据表明，PcTS/PcTS-Cu(2+)可被视为开发针对α-突触核蛋白相关神经退行性疾病的治疗或预防策略的可能候选物。
