Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia, United States of America.
PLoS One. 2011;6(10):e25752. doi: 10.1371/journal.pone.0025752. Epub 2011 Oct 5.
Alzheimer's disease (AD) is the most common form of dementia. AD is a degenerative brain disorder that causes problems with memory, thinking and behavior. It has been suggested that aggregation of amyloid-beta peptide (Aβ) is closely linked to the development of AD pathology. In the search for safe, effective modulators, we evaluated the modulating capabilities of erythrosine B (ER), a Food and Drug Administration (FDA)-approved red food dye, on Aβ aggregation and Aβ-associated impaired neuronal cell function.
METHODOLOGY/PRINCIPAL FINDINGS: In order to evaluate the modulating ability of ER on Aβ aggregation, we employed transmission electron microscopy (TEM), thioflavin T (ThT) fluorescence assay, and immunoassays using Aβ-specific antibodies. TEM images and ThT fluorescence of Aβ samples indicate that protofibrils are predominantly generated and persist for at least 3 days. The average length of the ER-induced protofibrils is inversely proportional to the concentration of ER above the stoichiometric concentration of Aβ monomers. Immunoassay results using Aβ-specific antibodies suggest that ER binds to the N-terminus of Aβ and inhibits amyloid fibril formation. In order to evaluate Aβ-associated toxicity we determined the reducing activity of SH-SY5Y neuroblastoma cells treated with Aβ aggregates formed in the absence or in the presence of ER. As the concentration of ER increased above the stoichiometric concentration of Aβ, cellular reducing activity increased and Aβ-associated reducing activity loss was negligible at 500 µM ER.
CONCLUSIONS/SIGNIFICANCE: Our findings show that ER is a novel modulator of Aβ aggregation and reduces Aβ-associated impaired cell function. Our findings also suggest that xanthene dye can be a new type of small molecule modulator of Aβ aggregation. With demonstrated safety profiles and blood-brain permeability, ER represents a particularly attractive aggregation modulator for amyloidogenic proteins associated with neurodegenerative diseases.
阿尔茨海默病（AD）是最常见的痴呆症形式。AD 是一种退行性脑疾病，可导致记忆、思维和行为问题。有人认为淀粉样β肽（Aβ）的聚集与 AD 病理学的发展密切相关。在寻找安全、有效的调节剂时，我们评估了食用红色素 B（ER）对 Aβ聚集和 Aβ相关的神经细胞功能障碍的调节能力，ER 是一种获得美国食品和药物管理局（FDA）批准的红色食品染料。
方法/主要发现：为了评估 ER 对 Aβ聚集的调节能力，我们采用了透射电子显微镜（TEM）、硫黄素 T（ThT）荧光测定法和使用 Aβ 特异性抗体的免疫测定法。Aβ 样品的 TEM 图像和 ThT 荧光表明，原纤维主要生成并至少持续 3 天。ER 诱导的原纤维的平均长度与 ER 的浓度成正比，高于 Aβ 单体的化学计量浓度。使用 Aβ 特异性抗体的免疫测定结果表明，ER 与 Aβ 的 N 端结合并抑制淀粉样纤维的形成。为了评估 Aβ 相关的毒性，我们测定了在不存在或存在 ER 的情况下形成的 Aβ 聚集体处理的 SH-SY5Y 神经母细胞瘤细胞的还原活性。随着 ER 的浓度高于 Aβ 的化学计量浓度，细胞还原活性增加，在 500µM ER 时，Aβ 相关的还原活性损失可以忽略不计。
结论/意义：我们的研究结果表明，ER 是 Aβ 聚集的新型调节剂，可降低 Aβ 相关的细胞功能障碍。我们的研究结果还表明，呫吨染料可以成为 Aβ 聚集的新型小分子调节剂。由于具有已证明的安全性和血脑通透性，ER 代表了与神经退行性疾病相关的淀粉样蛋白的特别有吸引力的聚集调节剂。
