Title "Molecular Pathogenesis of Parkinson's Disease"

为了阐明散发性帕金森病（PD）和伴路易小体痴呆（DLB）的分子发病机制，我们检测了α-突触核蛋白（aS）的改变，特别是翻译后修饰，α-突触核蛋白（aS）以路易小体（LB）为代表沉积在PD和DLB的病变神经元中。我们分析了从DLB皮质的不溶性部分纯化的aS，并通过质谱分析证明了沉积的aS的Ser129被磷酸化。磷酸化ser129特异性抗体显示aS广泛沉积为细胞内包裹体，如LBs，以及退行性神经突中的线状或点状沉积物。一部分磷酸化的aS在N端赖氨酸残基上被单泛素化。蛋白酶K酶切结果表明，aS的中间部分具有抗蛋白酶的核心结构。在神经元中表达aS的转基因果蝇在一部分神经元中表现出aS的磷酸化。在哺乳动物培养的细胞中，aS和synphilin-1的共表达表明，aS在Ser129位点的磷酸化有助于聚集体的形成和细胞死亡。基于这些结果，我们寻求通过抑制aS和其他致病蛋白的有害翻译后修饰来开发预防PD或DLB神经元死亡的治疗策略。

To elucidate the molecular pathogenesis of sporadic Parkinson's disease (PD) and dementia with Lewy bodies (DLB), we examined the alterations, especially posttranslational modifications, of α-synuclein (aS) that gets deposited in affected neurons of PD and DLB as fibrillary aggregates represented by Lewy bodies (LB). We analyzed aS purified from insoluble fractions of DLB cortices and demonstrated by mass spectrometry that Ser129 of deposited aS is phosphorylated. Phosphorylated Ser129-specific antibody revealed extensive deposition of aS as intracellular inclusions like LBs, as well as thread-or dot-like deposits in degenerating neurites. A fraction of phosphorylated aS was mono-ubiquitinated at the N- terminal Lys residues. Proteinase K digestion of aS filaments showed that the mid-portion of aS comprises the protease-resistant core structure. Transgenic Drosophila expressing aS in neurons exhibited phosphorylation of aS in a subset of neurons. Co-expression of aS and synphilin-1 in mammalian cultured cells showed that phosphorylation of aS at Ser129 contributes to aggregate formation and cell death. Based on these results, we seek to develop therapeutic strategies to prevent neuronal death in PD or DLB, by inhibiting noxious post-translational modification of aS and other pathogenic proteins.