Suppression of in vivo β-amyloid peptide toxicity by overexpression of the HSP-16.2 small chaperone protein
Suppression of in vivo β-amyloid peptide toxicity by overexpression of the HSP-16.2 small chaperone protein
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DOI：
10.1074/jbc.m703339200
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发表时间：
2008-01-11
影响因子：
4.8
通讯作者：
Link, Christopher D.
中科院分区：
文献类型：
--
作者：
Fonte, Virginia;Kipp, D. Randal;Link, Christopher D.
人β-淀粉样肽（A β）在转基因秀丽隐杆线虫阿尔茨海默病模型中的表达导致HSP-16蛋白的诱导，HSP-16蛋白是与脊椎动物α B晶状体蛋白同源的小的热休克诱导蛋白家族。在该模型中，这些蛋白质还与A β共定位和共免疫沉淀（Fonte，V.，Kebrkin，V.，塔夫脱，A.，Fluet，A.，弗里德曼，D.，和Link，C. D.等人（2002）Proc. Acad. Sci.联合S. A. 99，9439-9444）。为了研究HSP-16和A β之间相互作用的分子基础和生物学功能，我们产生了转基因C。elegans动物具有高水平的HSP-16.2的组成型表达。我们发现野生型HSP-16.2的组成型表达部分抑制A β毒性，但突变型HSP-16.2的组成型表达不抑制A β毒性。观察到野生型A β-（1-42），而不是A β单链二聚体，在含有HSP-16.2的包涵体中被隔离，表明HSP-16.2和A β在体内之间的构象依赖性相互作用。HSP-16.2的组成型表达可以减少淀粉样纤维的形成，但它并没有减少A β肽的总体积累或改变主要寡聚体种类的模式。用重组HSP-16.2进行的研究表明，HSP-16.2可以在体外直接与A β结合，对寡聚A β种类具有优先亲和力。A β和HSP-16.2之间的这种相互作用也影响体外测定中A β寡聚体的形成。这些研究与小分子伴侣蛋白通过直接与A β肽相互作用并改变其寡聚化途径，从而减少轻微毒性物质的形成，从而降低A β毒性的模型一致。
Expression of the human beta-amyloid peptide (A beta) in a transgenic Caenorhabditis elegans Alzheimer disease model leads to the induction of HSP-16 proteins, a family of small heat shock-inducible proteins homologous to vertebrate alpha B crystallin. These proteins also co-localize and co-immunoprecipitate with A beta in this model (Fonte, V., Kapulkin, V., Taft, A., Fluet, A., Friedman, D., and Link, C. D. (2002) Proc. Natl. Acad. Sci. U. S. A. 99, 9439-9444). To investigate the molecular basis and biological function of this interaction between HSP-16 and A beta, we generated transgenic C. elegans animals with high level, constitutive expression of HSP-16.2. We find that constitutive expression of wild type, but not mutant, HSP-16.2 partially suppresses A beta toxicity. Wild type A beta-(1-42), but not A beta single chain dimer, was observed to become sequestered in HSP-16.2-containing inclusions, indicating a conformation-dependent interaction between HSP-16.2 and A beta in vivo. Constitutive expression of HSP-16.2 could reduce amyloid fibril formation, but it did not reduce the overall accumulation of A beta peptide or alter the pattern of the predominant oligomeric species. Studies with recombinant HSP-16.2 demonstrated that HSP-16.2 can bind directly to A beta in vitro, with a preferential affinity for oligomeric A beta species. This interaction between A beta and HSP-16.2 also influences the formation of A beta oligomers in in vitro assays. These studies are consistent with a model in which small chaperone proteins reduce A beta toxicity by interacting directly with the A beta peptide and altering its oligomerization pathways, thereby reducing the formation of a minor toxic species.