体外聚集的β-内酰胺酶-聚谷氨酰胺嵌合体在体内秀丽隐杆线虫模型中不会诱导毒性作用。
In vitro aggregating β-lactamase-polyQ chimeras do not induce toxic effects in an in vivo Caenorhabditis elegans model.
作者信息
Van Assche Roel, Borghgraef Charline, Vaneyck Jonathan, Dumoulin Mireille, Schoofs Liliane, Temmerman Liesbet
机构信息
Animal Physiology and Neurobiology, Department of Biology, KU Leuven (University of Leuven), Zoological Institute, Naamsestraat 59, 3000, Leuven, Belgium.
Enzymology and Protein Folding, Center for Protein Engineering, InBioS, Institute of Chemistry, University of Liège, Sart-Tilman, 4000, Liège, Belgium.
出版信息
J Negat Results Biomed. 2017 Aug 22;16(1):14. doi: 10.1186/s12952-017-0080-5.
BACKGROUND
A series of human diseases are caused by the misfolding and aggregation of specific proteins or peptides into amyloid fibrils; nine of these diseases, referred to as polyglutamine diseases, are associated with proteins carrying an expanded polyglutamine (polyQ) region. While the presence of this latter is thought to be the determinant factor for the development of polyQ diseases, the non-polyQ regions of the host proteins are thought to play a significant modulating role.
METHOD
In order to better understand the role of non-polyQ regions, the toxic effects of model proteins bearing different polyQ regions (containing up to 79 residues) embedded at two distinct locations within the β-lactamase (BlaP) host enzyme were evaluated in Caenorhabditis elegans. This small organism can be advantageous for the validation of in vitro findings, as it provides a multicellular context yet avoids the typical complexity of common studies relying on vertebrate models. Several phenotypic assays were performed in order to screen for potential toxic effects of the different BlaP-polyQ proteins.
RESULTS
Despite the significant in vitro aggregation of BlaP-polyQ proteins with long polyQ regions, none of the BlaP-polyQ chimeras aggregated in the generated transgenic in vivo models.
CONCLUSION
The absence of a toxic effect of the expression of BlaP-polyQ chimeras may find its cause in biochemical mechanisms present in vivo to cope with protein aggregation (e.g. presence of chaperones) or in C. elegans' limitations such as its short lifespan. It is plausible that the aggregation propensities of the different BlaP chimeras containing embedded polyQ sequences are too low in this in vivo environment to permit their aggregation. These experiments emphasize the need for several comparative and in vivo verification studies of biologically relevant in vitro findings, which reveal both the strengths and limitations of widely used model systems.
背景
一系列人类疾病是由特定蛋白质或肽错误折叠并聚集成淀粉样原纤维引起的；其中九种疾病，即多聚谷氨酰胺疾病，与携带扩展多聚谷氨酰胺（polyQ）区域的蛋白质有关。虽然认为后者的存在是多聚谷氨酰胺疾病发生的决定性因素，但宿主蛋白的非多聚谷氨酰胺区域被认为起着重要的调节作用。
方法
为了更好地理解非多聚谷氨酰胺区域的作用，在秀丽隐杆线虫中评估了嵌入β-内酰胺酶（BlaP）宿主酶两个不同位置的带有不同多聚谷氨酰胺区域（含多达79个残基）的模型蛋白的毒性作用。这种小型生物对于体外研究结果的验证可能具有优势，因为它提供了多细胞环境，同时避免了依赖脊椎动物模型的常见研究的典型复杂性。进行了几种表型分析以筛选不同BlaP-多聚谷氨酰胺蛋白的潜在毒性作用。
结果
尽管带有长多聚谷氨酰胺区域的BlaP-多聚谷氨酰胺蛋白在体外有显著聚集，但在生成的转基因体内模型中，没有一种BlaP-多聚谷氨酰胺嵌合体发生聚集。
结论
BlaP-多聚谷氨酰胺嵌合体表达缺乏毒性作用，其原因可能在于体内存在的应对蛋白质聚集的生化机制（如伴侣蛋白的存在），或者在于秀丽隐杆线虫的局限性，如寿命较短。在这种体内环境中，不同的含有嵌入多聚谷氨酰胺序列的BlaP嵌合体的聚集倾向可能过低，以至于无法发生聚集，这似乎是合理的。这些实验强调了对生物学相关的体外研究结果进行多项比较和体内验证研究的必要性，这些研究揭示了广泛使用的模型系统的优势和局限性。
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