Validation and Characterization of a Novel Peptide That Binds Monomeric and Aggregated β-Amyloid and Inhibits the Formation of Neurotoxic Oligomers
Validation and Characterization of a Novel Peptide That Binds Monomeric and Aggregated β-Amyloid and Inhibits the Formation of Neurotoxic Oligomers
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DOI：
10.1074/jbc.m115.679993
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发表时间：
2016-01-08
影响因子：
4.8
通讯作者：
Martins, Ralph N.
中科院分区：
文献类型：
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作者：
Barr, Renae K.;Verdile, Giuseppe;Martins, Ralph N.
虽然大脑中形成的β-淀粉样蛋白(Aβ)沉积是阿尔茨海默病(AD)的一个标志，但导致Aβ毒性和神经变性的很可能是可溶低聚物，而不是成熟的淀粉样纤维。因此，发现针对可溶性Aβ寡聚体的药物对于临床AD表型表现之前的早期诊断和更有效的治疗是非常必要的。我们先前已经报道，通过噬菌体展示筛选得到一种新的15氨基酸多肽(15-mer)，它针对Aβ并减弱其神经毒性(Taddei，K.，Law，S.M.，Verdile，G.，Munns，S.，D‘Costa，K.，Harvey，A.R.，Martins，I.J.，Hill，F.，Levy，E.，Shaw，J.E.，以及Martins，R.N.(2010)Neurobiol)。年龄31岁，203-214岁)。目前这项研究的目的是产生和生化表征这种具有更好的稳定性和治疗潜力的类似物。我们证明了一种稳定的15氨基酸多肽类似物(15M S.A.)保留了亲本多肽的活性和效力，并在体外表现出更好的抗蛋白水解性(亲本多肽的稳定性为t=300min，c.f.t=30min)。该候选者减少了可溶性Aβ42低聚物的形成，同时产生了原子力显微镜测定的直径长达25-30 nm的无毒、不可溶聚集体。免疫共沉淀和表面等离子体共振/Biacore分析表明，15M SA候选者直接与低聚Aβ42相互作用，亲和力在低微摩尔范围内。此外，该多肽与Aβ42纤维蛋白结合，并在AD模型小鼠的体外脑组织中染色斑块。鉴于其多方面的能力，靶向单体和聚集的Aβ42种，这一候选具有前景的新的临床前AD成像和治疗策略。
Although the formation of beta-amyloid (A beta) deposits in the brain is a hallmark of Alzheimer disease (AD), the soluble oligomers rather than the mature amyloid fibrils most likely contribute to A beta toxicity and neurodegeneration. Thus, the discovery of agents targeting soluble A beta oligomers is highly desirable for early diagnosis prior to the manifestation of a clinical AD phenotype and also more effective therapies. We have previously reported that a novel 15-amino acid peptide (15-mer), isolated via phage display screening, targeted A beta and attenuated its neurotoxicity (Taddei, K., Laws, S. M., Verdile, G., Munns, S., D'Costa, K., Harvey, A. R., Martins, I. J., Hill, F., Levy, E., Shaw, J. E., and Martins, R. N. (2010) Neurobiol. Aging 31, 203-214). The aim of the current study was to generate and biochemically characterize analogues of this peptide with improved stability and therapeutic potential. We demonstrated that a stable analogue of the 15-amino acid peptide (15M S.A.) retained the activity and potency of the parent peptide and demonstrated improved proteolytic resistance in vitro (stable to t = 300 min, c.f.t = 30 min for the parent peptide). This candidate reduced the formation of soluble A beta 42 oligomers, with the concurrent generation of non-toxic, insoluble aggregates measuring up to 25-30 nm diameter as determined by atomic force microscopy. The 15M S.A. candidate directly interacted with oligomeric A beta 42, as shown by coimmunoprecipitation and surface plasmon resonance/Biacore analysis, with an affinity in the low micromolar range. Furthermore, this peptide bound fibrillar A beta 42 and also stained plaques ex vivo in brain tissue from AD model mice. Given its multifaceted ability to target monomeric and aggregated A beta 42 species, this candidate holds promise for novel preclinical AD imaging and therapeutic strategies.