PTGER4 and dermatitis: The up-regulated DEGs in the GPR15L-expressing NHEKs included a set of genes related to skin inflammation: CSF1 (encoding M-CSF, macrophage colony-stimulating factor), IL24 (IL-24), SOCS3, IL6 (IL-6), MAP3K11, CSF2 (GM-CSF, granulocyte-macrophage colony-stimulating factor), IL20 (IL-20), RELB, IL7R (a receptor for IL-7) and TSLP (thymic stromal lymphopoietin), PTGER4 (prostaglandin E2 receptor EP4), CIITA, and SEMA3E (Table 1).