Role of the mRNA-binding protein HuR in the global transcriptomic status of cells stimulated with electrophiles and oxidants

HuR has been implicated as a stress-responsive protein: cytoplasmic translocation of HuR is promoted by several small-molecule stressors, e.g., H2O2, arsenite, and the cyclopentenone prostaglandin A2 (PGA2), a Michael acceptor RES (Wang et al., 2000; Yang et al., 2004). Treatment with PGA2 also increases the affinity of HuR for p21 mRNA (Wang et al., 2000). Intrigued by these reports, we launched HuR-dependent gene-expression profiling studies in the presence and absence of small-molecule stress signals. HNE—a native RES with a reactive core chemically similar to that of PGA2—was selected as a representative bioactive RES (Jacobs and Marnett, 2009; Schopfer et al., 2011) and H2O2 was selected as a representative ROS. shHuR and shControl HEK293T cells were first generated and then treated with HNE or H2O2 under the conditions where cell viability is largely unaffected. We subsequently sequenced their RNA post ribosomal RNA (rRNA) depletion (see details below). Significant differential expression was evaluated with CuffDiff (Trapnell et al., 2013). 12 samples were analyzed (see below). Two biological replicates were included per cell line/treatment condition. Negative controls: shControl cell line; non-treated cells