Hexavalent chromium, a heavy metal toxicant, abundantly found in the environment showed hepatotoxic potential in zebrafish liver and instigated the Nrf2-Keap1-ARE pathway as a cellular stress response as reported in our previous studies. In the present study we have evaluated the ameliorating effect of shinorine, a mycosporine like amino acid (MAAs) and a mammalian Keap1 antagonist against chromium induced stress in zebrafish hepatocytes. Shinorine was found to be effective in increasing the cell viability of chromium treated hepatocytes through curtailing the cellular ROS content. Trigonelline, an Nrf2 inhibitor was found to reduce the viability of hepatocyte cultures co-exposed to shinorine and chromium. In other words, trigonelline being an Nrf2 blocker neutralised the alleviating effect of shinorine. This indicated that shinorine mediated cyto-protection in Cr [VI]-intoxicated cells is Nrf2 dependent. Further, qRT-PCR analysis revealed comparatively higher expression of nfe2l2 and nqo1 in shinorine + chromium treated hepatocytes than cells exposed to chromium alone indicating a better functioning of Nrf2-Keap1-Nqo1 axis. To further confirm if shinorine can lead to disruption of Nrf2-Keap1 interaction in zebrafish hepatocytes and render cytoprotection to chromium exposure, our in silico analysis through molecular docking revealed that shinorine could bind to the active amino acid residues of the DGR domain, responsible for Nrf2-Keap1 interaction of all the three Keap1s evaluated. This is the first report about shinorine that ameliorates chromium induced toxicity through acting as an Nrf2-Keap1 interaction disruptor. We additionally carried out in-silico pharmacokinetic and ADMET studies to evaluate druglikeness of shinorine whose promising results indicated its potential to be developed as an ideal therapeutic candidate against toxicant induced pathological conditions.

在我们的先前研究中报道，在环境中大量发现的六价铬（一种重金属毒物）在斑马鱼肝脏中显示出肝毒性潜力，并激发了Nrf2-Keap1-ARE途径作为细胞应激反应。在本研究中，我们评估了紫草碱，霉菌素样氨基酸（MAAs）和哺乳动物Keap1拮抗剂对铬引起的斑马鱼肝细胞应激的改善作用。发现Shinorine可通过减少细胞中ROS含量来有效提高铬处理的肝细胞的细胞活力。发现Trigonelline是一种Nrf2抑制剂，可降低与shinrine和铬共同暴露的肝细胞培养物的活力。换句话说，trigonelline是一种Nrf2阻滞剂，中和了shinorine的缓解作用。这表明在Cr [VI]中毒的细胞中，shinorine介导的细胞保护是Nrf2依赖性的。此外，qRT-PCR分析显示相对较高的与单独暴露于铬的细胞相比，经紫光碱+铬处理的肝细胞中的nfe2l2和nqo1表明Nrf2-Keap1-Nqo1轴的功能更好。为了进一步确认shinorine是否会导致斑马鱼肝细胞中Nrf2-Keap1相互作用的破坏并使其对铬的暴露具有细胞保护作用，我们通过分子对接进行的计算机分析表明shinorine可以与负责Nrf2的DGR域的活性氨基酸残基结合评估了所有三个Keap1的-Keap1相互作用。这是有关shinorine的第一个报告，该报告通过充当Nrf2-Keap1相互作用破坏剂来改善铬引起的毒性。我们还进行了计算机模拟 药代动力学和ADMET研究以评估shinorine的药物相似性，其有希望的结果表明其有可能被开发为对抗有毒物质引起的病理状况的理想治疗药物。