Department of Life Sciences, Chalmers University of Technology, 412 96 Gothenburg, Sweden.
Int J Mol Sci. 2023 Aug 16;24(16):12849. doi: 10.3390/ijms241612849.
The assembly of α-synuclein into cross-β structured amyloid fibers results in Lewy body deposits and neuronal degeneration in Parkinson's disease patients. As the cell environment is highly crowded, interactions between the formed amyloid fibers and a range of biomolecules can occur in cells. Although amyloid fibers are considered chemically inert species, recent in vitro work using model substrates has shown α-synuclein amyloids, but not monomers, to catalyze the hydrolysis of ester and phosphoester bonds. To search for putative catalytic activity of α-synuclein amyloids on biologically relevant metabolites, we here incubated α-synuclein amyloids with neuronal SH-SY5Y cell lysates devoid of proteins. LC-MS-based metabolomic (principal component and univariate) analysis unraveled distinct changes in several metabolite levels upon amyloid (but not monomer) incubation. Of 63 metabolites identified, the amounts of four increased (3-hydroxycapric acid, 2-pyrocatechuic acid, adenosine, and NAD), and the amounts of seventeen decreased (including aromatic and apolar amino acids, metabolites in the TCA cycle, keto acids) in the presence of α-synuclein amyloids. Many of these metabolite changes match what has been reported previously in Parkinson's disease patients and animal-model metabolomics studies. Chemical reactivity of α-synuclein amyloids may be a new gain-of-function that alters the metabolite composition in cells and, thereby, modulates disease progression.
α-突触核蛋白聚集成交叉β结构的淀粉样纤维会导致帕金森病患者的路易体沉积和神经元变性。由于细胞环境高度拥挤，形成的淀粉样纤维与一系列生物分子之间可能在细胞内发生相互作用。尽管淀粉样纤维被认为是化学惰性物质，但最近使用模型底物的体外研究表明，α-突触核蛋白淀粉样纤维而不是单体能够催化酯和磷酸酯键的水解。为了寻找α-突触核蛋白淀粉样纤维对生物相关代谢物的潜在催化活性，我们在此将α-突触核蛋白淀粉样纤维与缺乏蛋白质的神经元 SH-SY5Y 细胞裂解物一起孵育。基于 LC-MS 的代谢组学（主成分和单变量）分析揭示了在淀粉样纤维（而非单体）孵育时几种代谢物水平的明显变化。在鉴定出的 63 种代谢物中，有 4 种（3-羟基辛酸、2-邻苯二酚、腺苷和 NAD）的含量增加，而 17 种（包括芳香族和非极性氨基酸、TCA 循环中的代谢物、酮酸）的含量减少。这些代谢物变化中的许多与帕金森病患者和动物模型代谢组学研究中先前报道的变化相匹配。α-突触核蛋白淀粉样纤维的化学反应性可能是一种新的功能获得，它改变了细胞中的代谢物组成，从而调节疾病进展。
