Skip to main content
. 2015 Nov 23;2:57. doi: 10.3389/fvets.2015.00057

Figure 6.

Figure 6

Host defense peptide-mediated signaling pathways to induce mucins and tight junction proteins in epidermal and intestinal epithelial cells. (A) LL-37 primarily utilizes purinergic receptor P2X7 and transactivates EGFR to mediate MUC2 and MUC5AC induction. (B) LL-37 induces the synthesis of multiple claudins and occludin in skin keratinocytes mainly through PI3K-GSK-3α/β and Rac1-aPKCζ/λ pathways; however, the receptor that mediates the effect is currently unknown. (C) HBD-3 mainly engages CCR6 to induce claudin synthesis in skin keratinocytes through the PI3K-GSK-3α/β and Rac1-aPKCζ/λ pathways. (D) S100A7 enhances the synthesis of claudins and occludin through PI3K-GSK-3α/β and three canonical MAPK pathways. S100A7 also triggers phosphorylation of β-catenin and E-cadherin to enhance the adherens junction. A solid arrow indicates a direct effect, whereas a dashed arrow refers to an indirect action. It is noted that cross-talks among different signaling pathways likely exist, but they have not been reported.