Muroi Yukiko, Aburaya Izumi, Shima Takuro, Matsumoto Mitsuharu, Sasahara Ryo, Suzuki Takahisa, Watanabe Keiichi, Wada Koji, Sugimoto Yasushi
Faculty of Food and Nutrition, Kyushu Nutrition and Welfare University, 5-1-1 Shimoitozu, Kokura-Kitaku, Kitakyushu 803-8511, Japan.
Department of Food Function Chemistry, The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
J Poult Sci. 2022 Oct 25;59(4):384-391. doi: 10.2141/jpsa.0220038.
Amyloid fibrils, which are formed from aggregates of aberrant proteins, can cause various forms of amyloidosis (including Alzheimer's disease). Such disorders often occur in elderly populations and are suspected to be lifestyle related. Thus, it has been speculated that some foodstuffs could be beneficial for preventing amyloidosis. In this study, we determine whether fibril formation by the hen egg white lysozyme (HEWL) could be inhibited by conducting a thioflavin T assay followed by fluorescence and electron microscopy observations. The results demonstrated that four peptide specimens prepared by the hydrolysis of crude proteins from the egg white, egg yolk, chalazae, and eggshell membrane of hen eggs effectively inhibited HEWL fibril formation. Among the four specimens, peptides from chalazae exhibited the highest preventive ability. The superiority of chalaza peptides was also observed when fibril formation was assayed using a full-length human lysozyme and human amyloid peptide 1-42, which is the key factor for the development of Alzheimer's disease. Our study of the fibrillization of the human lysozyme also showed that metal ions (Zn, Ca, Co, Mn and Al) promoted fibrillization, and their effects were abolished by the peptide specimens (especially by chalaza peptides). Thus, we conclude that chicken-egg proteins could be a convenient source of therapeutic materials for amyloidosis.
淀粉样纤维由异常蛋白质聚集体形成，可导致各种形式的淀粉样变性（包括阿尔茨海默病）。此类疾病常发生于老年人群，且被怀疑与生活方式有关。因此，有人推测某些食物可能有助于预防淀粉样变性。在本研究中，我们通过硫黄素T检测，随后进行荧光和电子显微镜观察，来确定鸡蛋白溶菌酶（HEWL）的纤维形成是否能够被抑制。结果表明，通过水解鸡蛋的蛋清、蛋黄、系带和蛋壳膜中的粗蛋白制备的四种肽标本有效地抑制了HEWL纤维的形成。在这四种标本中，来自系带的肽表现出最高的预防能力。当使用全长人溶菌酶和人淀粉样肽1-42（阿尔茨海默病发展的关键因素）检测纤维形成时，也观察到了系带肽的优势。我们对人溶菌酶纤维化的研究还表明，金属离子（锌、钙、钴、锰和铝）促进纤维化，而肽标本（尤其是系带肽）消除了它们的作用。因此，我们得出结论，鸡蛋蛋白可能是治疗淀粉样变性的便捷治疗材料来源。
