Regeneration-inducing tetradecapeptide tekkrretvereke activates mapk-kinase signaling in NIH/3T3 fibroblasts

We previously reported that the erosion, ulcer and wound healing tetradecapeptide TEKKRRETVEREKE (immunomodulatory preparation Gepon) induces the fbroblast-to-myofbroblast differentiation and also enhances cell motility in the scratch-test [1]. In this study we compared intracellular signaling events in NIH/3T3 fbroblasts after their activation with TEKKRRETVEREKE tetradecapeptide or TGF-β1 cytokine, a natural fbroblast-activating compound. Activation of the canonical (SMAD) and non-canonical (MAPK) signaling pathways was measured. Also transcription levels for a-sma, col1a1 and tgf-β1 genes associated with a differentiation of fbroblasts were estimated. It was shown that the tetradecapeptide activates a transcription of a-sma and col1a1 genes in a manner similar to that of TGF-β1. In opposite to TGF-β1, the tetradecapeptide TEKKRRETVEREKE did not induce a transcription of tgf-β1 gene. TGF-β1 induced SMAD2-phosphorylation in NIH/3T3 fbroblasts, while the tetradecapeptide did not. In few minutes after application to NIH/3T3 cell cultures, both TGF-β1 and tetradecapeptide TEKKRRETVEREKE strongly activated the non-canonical MAPK-pathway with a prominent activation of ERK1/2-phosphorylation and its translocation into cell nucleus. Thus, a wound healing tetradecapeptide TEKKRRETVEREKE and TGF-β1 cytokine differently activate fbroblasts. Both compounds induce activation of the MAPK-kinase signaling pathway and also a-sma and col1a1 genes transcription, but only TGF-β1 activates canonical SMAD-signaling pathway and transcription of tgf-β1 gene.