Department of Chemistry, Stony Brook University, Stony Brook, NY, United States of America.
Institute of Structural and Molecular Biology, University College London, Gower Street, London, United Kingdom.
PLoS One. 2019 Aug 12;14(8):e0219130. doi: 10.1371/journal.pone.0219130. eCollection 2019.
The development of inhibitors of islet amyloid formation is important as pancreatic amyloid deposition contributes to type-2 diabetes and islet transplant failure. The Alzheimer's Aβ peptide and human amylin (h-amylin), the polypeptide responsible for amyloid formation in type-2 diabetes, share common physio-chemical features and some inhibitors of Aβ also inhibit amyloid formation by h-amylin and vice versa. Thus, a popular and potentially useful strategy to find lead compounds for anti-amylin amyloid agents is to examine compounds that have effects on Aβ amyloid formation. The triphenylmethane dye, brilliant blue G (BBG, Sodium;3-[[4-[(E)-[4-(4-ethoxyanilino)phenyl]-[4-[ethyl-[(3-sulfonatophenyl)methyl]azaniumylidene]-2-methylcyclohexa-2,5-dien-1-ylidene]methyl]-N-ethyl-3-methylanilino]methyl]benzenesulfonate) has been shown to modulate Aβ amyloid formation and inhibit Aβ induced toxicity. However, the effects of BBG on h-amylin have not been examined, although other triphenylmethane derivatives inhibit h-amylin amyloid formation. The compound has only a modest impact on h-amylin amyloid formation unless it is added in significant excess. BBG also remodels preformed h-amylin amyloid fibrils if added in excess, however BBG has no significant effect on h-amylin induced toxicity towards cultured β-cells or cultured CHO-T cells except at high concentrations. BBG is shown to interfere with standard thioflavin-T assays of h-amylin amyloid formation and disaggregation, highlighting the difficulty of interpreting such experiments in the absence of other measurements. BBG also interferes with ANS based assays of h-amylin amyloid formation. The work highlights the differences between inhibition of Aβ and h-amylin amyloid formation, illustrates the limitation of using Aβ inhibitors as leads for h-amylin amyloid inhibitors, and reinforces the difficulties in interpreting dye binding assays of amyloid formation.
胰岛淀粉样形成抑制剂的开发非常重要，因为胰腺淀粉样沉积会导致 2 型糖尿病和胰岛移植失败。阿尔茨海默病的 Aβ肽和人类胰岛淀粉样多肽（h-胰岛淀粉样多肽），是导致 2 型糖尿病淀粉样形成的多肽，具有共同的理化特征，一些 Aβ抑制剂也能抑制 h-胰岛淀粉样多肽的淀粉样形成，反之亦然。因此，寻找抗胰岛淀粉样多肽淀粉样形成的先导化合物的一种流行且潜在有用的策略是研究对 Aβ淀粉样形成有影响的化合物。三苯甲烷染料亮蓝 G（BBG，Sodium;3-[[4-[(E)-[4-(4-乙氧基苯胺基)苯基]-[4-[乙基-[(3-磺酸钠基苯基)甲基]亚氨基]-2-甲基环己-2,5-二烯-1-基]亚甲基]-N-乙基-3-甲基苯胺基]甲基]苯磺酸盐）已被证明能调节 Aβ淀粉样形成并抑制 Aβ诱导的毒性。然而，尚未研究 BBG 对 h-胰岛淀粉样多肽的影响，尽管其他三苯甲烷衍生物能抑制 h-胰岛淀粉样多肽的淀粉样形成。除非添加大量的 BBG，否则该化合物对 h-胰岛淀粉样形成的影响不大。如果添加过量，BBG 还会重塑预先形成的 h-胰岛淀粉样纤维，但 BBG 对培养的β细胞或培养的 CHO-T 细胞的 h-胰岛淀粉样多肽诱导的毒性没有显著影响，除非浓度较高。结果表明，BBG 会干扰用于检测 h-胰岛淀粉样多肽淀粉样形成和去聚集的标准噻唑蓝-T 试验，突出了在没有其他测量的情况下解释这些实验的困难。BBG 还会干扰用于检测 h-胰岛淀粉样多肽淀粉样形成的 ANS 基础试验。该研究强调了抑制 Aβ和 h-胰岛淀粉样形成之间的差异，说明了将 Aβ抑制剂用作 h-胰岛淀粉样多肽抑制剂的先导的局限性，并强调了解释淀粉样形成的染料结合试验的困难。
