Effects of CSE on ACE2 expression in human cell lines. (a,b) Expression levels of CYP1A1 and ACE2 genes in various concentrations of CSE treated HepG2 (Liver origin) cells for 24 h were evaluated by qRT-PCR. Relative gene expression levels were calculated by using ACTB expression as the denominator for each cell line (n = 3). For all quantitative values, the average and SD are shown. Statistical significance was calculated for the indicated paired samples with ** representing P < 0.01. Gene set enrichment analyses for gene lists analyzed by RNA-seq were performed with Metascape. Upregulated genes [log2(CSE-DMSO) ≥ 1] (c) in CSE treated HepG2 cells and downregulated genes [log2(CSE-DMSO) ≤ -1] (e) were enriched by gene ontology (GO) term. Process enrichment analyses using TRRUST showed human transcriptional regulatory interactions in upregulated genes (d). AHR and ARNT, hetero-dimeric transcriptional partners, are indicated with red boxes.