Shinorine Ameliorates Chromium Induced Toxicity In Zebrafish Hepatocytes Through The Facultative Activation Of Nrf2-Keapl-Are Pathway

Hexavalent chromium, a heavy metal toxicant, abundantly found in the environment showed hepatotoxic potential in zebrafish liver and instigated the Nrf2-Keapl-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 Keapl 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 nfe212 and nqol in shinorine + chromium treated hepatocytes than cells exposed to chromium alone indicating a better functioning of Nrf2-Keapl-Nqol axis. To further confirm if shinorine can lead to disruption of Nrf2-Keapl 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-Keapl interaction of all the three Keapls evaluated. This is the first report about shinorine that ameliorates chromium induced toxicity through acting as an Nrf2-Keapl 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.