Expression Levels of the Immune-Related p38 Mitogen-Activated Protein Kinase Transcript in Response to Environmental Pollutants onMacrophthalmus japonicusCrab

Environmental pollution in the aquatic environment poses a threat to the immune system of benthic organisms. TheMacrophthalmus japonicuscrab, which inhabits tidal flat sediments, is a marine invertebrate that provides nutrient and organic matter cycling as a means of purification. Here, we characterized theM. japonicusp38 mitogen-activated protein kinase (MAPK) gene, which plays key roles in the regulation of cellular immune and apoptosis responses.M. japonicusp38 MAPKdisplayed the characteristics of the conservedMAPKfamily with Thr-Gly-Tyr (TGY) motif and substrate-binding site Ala-Thr-Arg-Trp (ATRW). The amino acid sequence of theM. japonicus p38 MAPKshowed a close phylogenetic relationship toEriocheir sinensis MAPK14andScylla paramamosainp38 MAPK. The phylogenetic tree displayed two origins ofp38 MAPK: crustacean and insect. The tissue distribution patterns showed the highest expression in the gills and hepatopancreas ofM. japonicuscrab. In addition,p38 MAPKexpression inM. japonicusgills and hepatopancreas was evaluated after exposure to environmental pollutants such as perfluorooctane sulfonate (PFOS), irgarol, di(2-ethylhexyl) phthalate (DEHP), and bisphenol A (BPA). In the gills,p38 MAPKexpression significantly increased after exposure to all concentrations of the chemicals on day 7. However, on day 1, there were increasedp38 MAPKresponses observed after PFOS and irgarol exposure, whereas decreasedp38 MAPKresponses were observed after DEHP and BPA exposure. The upregulation ofp38 MAPKgene also significantly led toM. japonicushepatopancreas being undertested in all environmental pollutants. The findings in this study supported that anti-stress responses against exposure to environmental pollutants were reflected in changes in expression levels inM. japonicusp38 MAPKsignaling regulation as a cellular defense mechanism.