Neurotoxicity of methylmercury in Drosophila embryo development

甲基汞对果蝇胚胎发育的神经毒性

• 批准号: 8590009
• 负责人: MATTHEW D RAND
• 金额: $ 6.55万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-11-06 至 2014-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8590009
• 关键词: Neurotoxicity; methylmercury; Drosophila; embryo; development

DESCRIPTION (provided by applicant): Methylmercury (MeHg) is a persistent environmental neurotoxin that poses a health risk to humans due to its accumulation in dietary fish. Epidemiological and laboratory studies have established that the developing nervous system is exceptionally sensitive to MeHg toxicity. Our overall goal is to elucidate the fundamental mechanisms of neural development that are targeted by MeHg toxicity. The extent to which MeHg selectively alters neurogenesis versus cell fates, neuronal migration and/or neuron morphology remains unclear. It is well understood, however, that these neural developmental events are temporally regulated over the course of embryogenesis. Our hypothesis is that MeHg will show a preferentially higher activity toward disruption of one of four neural developmental events: neuroblast specification, neuron sibling cell fates, neuronal/glial migration or neuron morphogenesis. We therefore predict that susceptibility of the embryonic nervous system to MeHg toxicity will vary with the developmental timing of MeHg exposure. We will test this hypothesis with the Drosophila embryo model. Our study is made feasible by our breakthrough innovation of an embryo permeabilization solvent (EPS) that overcomes the longstanding technical barrier of permeating of the fruit fly eggshell while maintaining embryo viability. EPS treatment enables delivery of defined doses of small molecules to embryos cultured in vitro. By applying MeHg to the Drosophila embryo at discrete developmental time points and monitoring phenotypes in well characterized neural lineages we expect to elucidate whether early (neurogenesis and cell fate specification) or late (neuron migration and morphogenesis) development events are the most susceptible to MeHg toxicity. As EPS is a new application we will first take steps to calibrate levels of embryo permeability and perform MeHg dosimetry with treated embryos. We will then apply this methodology to available transgenic fly strains with lineage-specific reporter genes to determine the most vulnerable neural developmental mechanisms. Since many of the signaling pathways underlying neural development in the fly embryo are highly conserved, we expect these results will drive the rationale for more focused molecular studies on MeHg targets in higher organisms and in humans. Our novel embryo permeabilization innovation is an enabling step in executing accurate doses to the fly embryo. Therefore, we also view this study as essential for establishing the utility of this experimental approach for the broader toxicological research community.

描述（由申请人提供）：甲基汞（MeHg）是一种持久性环境神经毒素，由于其在食用鱼类中积累，对人类构成健康风险。 流行病学和实验室研究表明，发育中的神经系统对甲基汞毒性特别敏感。 我们的总体目标是阐明神经发育的基本机制，有针对性的甲基汞毒性。甲基汞选择性改变神经发生与细胞命运、神经元迁移和/或神经元形态的程度仍不清楚。 然而，众所周知，这些神经发育事件在胚胎发生过程中受到时间调控。 我们的假设是，甲基汞将显示出优先更高的活动对破坏的四个神经发育事件之一：神经母细胞规格，神经元同胞细胞的命运，神经元/神经胶质细胞迁移或神经元形态发生。 因此，我们预测，胚胎神经系统对甲基汞毒性的敏感性将随甲基汞暴露的发育时间而变化。 我们将用果蝇胚胎模型来检验这一假设。 我们的研究是可行的，我们的突破性创新的胚胎透化溶剂（EPS），克服了长期存在的技术障碍，渗透的果蝇蛋壳，同时保持胚胎的活力。 EPS治疗能够将确定剂量的小分子递送至体外培养的胚胎。 通过将甲基汞应用于果蝇胚胎在离散的发育时间点和监测表型特征良好的神经谱系，我们希望阐明早期（神经发生和细胞命运规范）或晚期（神经元迁移和形态发生）的发展事件是最容易受到甲基汞毒性。 由于EPS是一种新的应用，我们将首先采取措施校准胚胎渗透性水平，并对经处理的胚胎进行甲基汞剂量测定。 然后，我们将这种方法应用于可用的转基因果蝇品系与谱系特异性报告基因，以确定最脆弱的神经发育机制。由于许多信号通路的神经发育的苍蝇胚胎是高度保守的，我们预计这些结果将推动更集中的甲基汞在高等生物和人类的目标分子研究的理由。 我们的新型胚胎透化创新是对苍蝇胚胎执行精确剂量的一个有利步骤。 因此，我们也认为这项研究对于建立更广泛的毒理学研究社区的实验方法的效用至关重要。