扇贝中氮杂螺环酸毒素的葡萄糖醛酸化代谢调控研究

Azaspiracids (AZAs), one kind of lipid-soluble shellfish toxins, with the lowest provisional acute reference dose(ARfD) and relative high toxicity among all kinds of shellfish toxins, are easily accumulate to high level in shellfish.and persistent for a long time. Consumption of AZAs contaminated shellfish causes a severe acute gastrointestinal poisoning, leading to ecological perturbations, threats to public health, and concerns about quality of shellfish products. In recent years, AZAs contamination have become a worldwide problem. To date, AZAs producing microalgaes are extensively distributed around the offshore of China. This has induce an increasingly deteriorating residue level of AZAs in shellfish product. These facts means that it is urgent and necessary to assess the potential risk of AZAs in shellfish. However, AZAs detoxinfication mechanism is still poorly documented. This will give an inaccuracy of the safety assessment. Azaspiracids (AZAs) are cyclic polyethers with special carboxylic group, posed that glucuronidation pathway might be the main potential phase II metabolism path. In this research, the scallop Chlamys Farreri is selected as the research organism for its high residue risk of AZAs. The scallop is firstly exposed to one AZAs-producing microalgae, Azadinium poporum(Strain AZDY06), to illuminate the leading role of glucuronidation pathway in metabolism process of AZAs and its key regulatory factors. The metabolic pathways and multivariate data are analyzed by using metabolomics technology to screen differential metabolites. Based on gene expression profile analysis, transcriptome-metabolomics network is correlated and described. This network illustrated the correlation between differential gene expression and AZAs metabolic regulation, in order to reveal the mechanism regulation of target genes in AZAs detoxification pathway. This project will be helpful to deeply understand the metabolic mechanism of AZAs, and provide the theoretical basis for the establishment of maximum residue limits(MRLs) and safety control measures in China.

氮杂螺环酸毒素（azaspiracids，AZAs）为一类毒性强、残留高且代谢慢的脂溶性贝类毒素，已成国际研究热点和管控重点。AZAs产毒藻在我国近海分布广泛，造成贝类中AZAs残留风险日趋严重。然而，由于缺乏对贝类中AZAs代谢过程，尤其是其特征性葡萄糖醛酸化通路的科学认知，致使我国无法准确评价其安全风险。项目以我国风险严峻的栉孔扇贝为研究对象，将其暴露于AZAs优势产毒藻，利用代谢组学技术筛选差异性代谢产物，进行代谢通路与多变量数据分析，明确葡萄糖醛酸化通路对AZAs代谢的主导作用及其关键调控因子；结合转录组基因表达谱分析，构建代谢组-转录组关联解析网络，揭示葡萄糖醛酸化酶基因差异表达对AZAs醛酸化通路的影响，最终阐明目标基因对AZAs代谢调控作用机制。项目有助于深层次了解贝类对AZAs代谢机制，为我国科学制定限量标准并构建安全防控措施提供理论依据。

氮杂螺环酸毒素（Azaspiracids，AZAs）是近年来新发现的一类藻毒素，具有高残留和强毒性的特点，为国际社会重点关注。本研究以分离自我国沿海的一株AZAs产毒藻（AZDY06株）为研究对象，采用室内胁迫栉孔扇贝的方式，通过生物应激、代谢组学和转录组学三个研究手段的组合思路进一步探索栉孔扇贝应激AZAs胁迫的分子机制，主要研究结果如下：AZA通过两相协同促毒素代谢：I相代谢是混合功能氧化酶系统和P450；II相代谢是谷胱甘肽结合物和葡萄糖醛酸化代谢物；贝类对AZA2的蓄积和吸收由血细胞开始，特点是迅速（3h）；AZA强毒性作用触发多种氧化应激反应，同时导致扇贝氧化应激功能破坏，尤其是对肠道的破坏导致代谢效率低；代谢和排泄过程主要通过膜动转运-转运蛋白ABC，饱和性影响转运速率；线粒体和溶酶体参与了毒素的免疫调控和细胞凋亡，尤其是能量代谢ATP持续降低至14d；花生四烯酸代谢、谷氨酰胺和色氨酸物质代谢在免疫和代谢均显著相关，为潜在的促代谢靶点。本研究从多个角度探索栉孔扇贝应激胁迫的分子机制，为深度解析栉孔扇贝对AZAs的解毒机制提供了理论支持和数据基础。