新蛋白：老年痴呆症的利好消息
2010-08-11 01:44:37   来源：英文   评论：0 点击：

　　Prions Involved in Some Alzheimer's

　　It's like the molecular version of the Joker and the Riddler teaming up against Batman. Scientists at Yale University have discovered that amyloid beta, a protein involved in Alzheimer’s disease, can damage brain cells by binding to prion proteins, which are themselves infamous because, in their abnormal form, they cause things like mad cow disease.

　　Amyloid beta is best known as the protein that forms the giant plaques that riddle the brains of people with Alzheimer’s. Those plaques contain billions of copies of amyloid beta all stuck together in one gloppy mess. But the protein also exists in a more soluble form, either in single units or in small groups of 50 or 100. These smaller clusters don’t cause the same large-scale mayhem as plaques, but they do damage neurons, impairing their ability to learn. And the Yale researchers wanted to find out how.

　　They discovered that amyloid beta binds to the prion proteins normally found on neurons. What’s more, the prions ramp up amyloid beta’s neurotoxic effects. Taking away the prions and amyloid-beta clusters are harmless, findings published in the journal Nature. So drugs that prevent this amyloid–prion coupling could be a potent weapon against Alzheimer’s.

　　朊病毒与有些老年痴呆症相关

　　耶鲁大学的科学家们发现，淀粉样蛋白（一种与老年痴呆症有关的蛋白）能通过结合朊病毒蛋白对大脑造成损害，朊病毒蛋白本身就“臭名昭著”，因为它们的变体能导致诸如疯牛病之类的病害。看来，淀粉样蛋白与朊病毒蛋白的“狼狈为奸”就像是《蝙蝠侠》里面的Joker 和Riddler 一样勾结在一起与蝙蝠侠作对。

　　众所周知，淀粉样蛋白导致老年痴呆症患者的大脑里面形成巨大的斑块。这些斑块含有数十亿的：-淀粉样蛋白拷贝，它们乱七八糟地堆积在一起形成一个糊状的大块。不过这些蛋白质也以更加易溶的形式存在，它们要么以单个单元存在，要么由50个或者100个蛋白质构成一个小群体。虽然这些小一点儿的团簇不会像斑块那样造成大规模的混乱，但是它们也的确损害对神经元，影响神经元学习的能力。耶鲁大学的研究人员们想发现这到底是如何进行的。

　　研究人员发现与，淀粉样蛋白与通常是在神经元上发现的朊病毒蛋白结合在一起。而且，朊病毒蛋白增强了， 淀粉样蛋白的神经毒性。发表在《自然》(Nature)杂志上的研究表明，取走淀粉样蛋白和朊病毒蛋白团簇不会对患者造成伤害。所以能防止淀粉样蛋白和朊病毒蛋白结合的药物可能会成为治疗老年痴呆症的强有力武器。