De Simone Angela, Naldi Marina, Tedesco Daniele, Milelli Andrea, Bartolini Manuela, Davani Lara, Widera Darius, Dallas Mark L, Andrisano Vincenza
Department for Life Quality Studies, Alma Mater Studiorum Università di Bologna, Rimini 47921, Italy.
Department of Pharmacy and Biotechnology, Alma Mater Studiorum Università di Bologna, Bologna 40126, Italy.
ACS Omega. 2019 Jul 18;4(7):12308-12318. doi: 10.1021/acsomega.9b01531. eCollection 2019 Jul 31.
The self-assembly of amyloid peptides (Aβ), in particular Aβ, into oligomers and fibrils is one of the main pathological events related to Alzheimer's disease. Recent studies have demonstrated the ability of carbon monoxide-releasing molecules (CORMs) to protect neurons and astrocytes from Aβ toxicity. In fact, CORMs are able to carry and release controlled levels of CO and are known to exert a wide range of anti-inflammatory and anti-apoptotic activities at physiologically relevant concentrations. In order to investigate the direct effects of CORMs on Aβ, we studied the reactivity of CORM-2 and CORM-3 with Aβ and the potential inhibition of its aggregation by mass spectrometry (MS), as well as fluorescence and circular dichroism spectroscopies. The application of an electrospray ionization-MS (ESI-MS) method allowed the detection of stable Aβ/CORMs adducts, involving the addition of the Ru(CO) portion of CORMs at histidine residues on the Aβ skeleton. Moreover, CORMs showed anti-aggregating properties through formation of stable adducts with Aβ as demonstrated by a thioflavin T fluorescence assay and MS analysis. As further proof, comparison of the CD spectra of Aβ recorded in the absence and in the presence of CORM-3 at a 1:1 molar ratio showed the ability of CORM-3 to stabilize the peptide in its soluble, unordered conformation, thereby preventing its misfolding and aggregation. This multi-methodological investigation revealed novel interactions between Aβ and CORMs, contributing new insights into the proposed neuroprotective mechanisms mediated by CORMs and disclosing a new strategy to divert amyloid aggregation and toxicity.
淀粉样肽（Aβ），特别是Aβ自组装成寡聚体和原纤维是与阿尔茨海默病相关的主要病理事件之一。最近的研究表明，一氧化碳释放分子（CORMs）能够保护神经元和星形胶质细胞免受Aβ毒性的影响。事实上，CORMs能够携带并释放可控水平的CO，并且已知在生理相关浓度下发挥广泛的抗炎和抗凋亡活性。为了研究CORMs对Aβ的直接作用，我们通过质谱（MS）以及荧光和圆二色光谱研究了CORM-2和CORM-3与Aβ的反应性及其对Aβ聚集的潜在抑制作用。电喷雾电离-MS（ESI-MS）方法的应用使得能够检测到稳定的Aβ/CORMs加合物，这涉及CORMs的Ru(CO)部分在Aβ骨架上的组氨酸残基处的添加。此外，硫黄素T荧光测定和MS分析表明，CORMs通过与Aβ形成稳定的加合物而表现出抗聚集特性。作为进一步的证据，在不存在和存在摩尔比为1:1的CORM-3的情况下记录的Aβ的圆二色光谱比较表明，CORM-3能够将肽稳定在其可溶的无序构象中，从而防止其错误折叠和聚集。这种多方法研究揭示了Aβ与CORMs之间的新相互作用，为CORMs介导的拟议神经保护机制提供了新的见解，并揭示了一种转移淀粉样蛋白聚集和毒性的新策略。
