Chemistry Department and Coimbra Chemistry Centre, University of Coimbra, 3004-535 Coimbra, Portugal.
International Iberian Nanotechnology Laboratory, 4715-330 Braga, Portugal.
Molecules. 2020 Dec 3;25(23):5698. doi: 10.3390/molecules25235698.
One of the molecular hallmarks of amyloidoses is ordered protein aggregation involving the initial formation of soluble protein oligomers that eventually grow into insoluble fibrils. The identification and characterization of molecular species critical for amyloid fibril formation and disease development have been the focus of intense analysis in the literature. Here, using photo-induced cross-linking of unmodified proteins (PICUP), we studied the early stages of oligomerization of human transthyretin (TTR), a plasma protein involved in amyloid diseases (ATTR amyloidosis) with multiple clinical manifestations. Upon comparison, the oligomerization processes of wild-type TTR (TTRwt) and several TTR variants (TTRV30M, TTRL55P, and TTRT119M) clearly show distinct oligomerization kinetics for the amyloidogenic variants but a similar oligomerization mechanism. The oligomerization kinetics of the TTR amyloidogenic variants under analysis showed a good correlation with their amyloidogenic potential, with the most amyloidogenic variants aggregating faster (TTRL55P > TTRV30M > TTRwt). Moreover, the early stage oligomerization mechanism for these variants involves stepwise addition of monomeric units to the growing oligomer. A completely different behavior was observed for the nonamyloidogenic TTRT119M variant, which does not form oligomers in the same acidic conditions and even for longer incubation times. Thorough characterization of the initial steps of TTR oligomerization is critical for better understanding the origin of ATTR cytotoxicity and developing novel therapeutic strategies for the treatment of ATTR amyloidosis.
淀粉样变的分子特征之一是有序的蛋白质聚集，涉及可溶性蛋白寡聚物的初始形成，这些寡聚物最终生长成不溶性纤维。鉴定和表征对淀粉样纤维形成和疾病发展至关重要的分子种类一直是文献中深入分析的重点。在这里，我们使用未经修饰蛋白的光诱导交联（PICUP）研究了人转甲状腺素蛋白（TTR）的寡聚化的早期阶段，TTR 是一种与多种临床表现相关的淀粉样疾病（ATTR 淀粉样变性）的血浆蛋白。比较后，野生型 TTR（TTRwt）和几种 TTR 变体（TTRV30M、TTRL55P 和 TTRT119M）的寡聚化过程清楚地表明，淀粉样变体的寡聚化动力学明显不同，但寡聚化机制相似。分析的 TTR 淀粉样变体的寡聚化动力学与它们的淀粉样形成潜能具有良好的相关性，最具淀粉样形成潜能的变体聚集得更快（TTRL55P>TTRV30M>TTRwt）。此外，这些变体的早期寡聚化机制涉及单体单元逐步添加到生长的寡聚物中。对于非淀粉样形成的 TTRT119M 变体，观察到完全不同的行为，即在相同的酸性条件下甚至在更长的孵育时间内，它都不会形成寡聚物。彻底表征 TTR 寡聚化的初始步骤对于更好地理解 ATTR 细胞毒性的起源和开发治疗 ATTR 淀粉样变性的新型治疗策略至关重要。
