The role of hyaluronic acid receptor (CD44) in activation mechanisms of NIH/3T3 fibroblast with the tekkrretvereke synthetic peptide versus TgF-β1 cytokine

We have previously shown that TEKKRRETVEREKE tetradecapeptide (a healing therapeutics gepon) induces activation of MAPK-signalling pathway in murine NIH/3T3 fibroblasts with their subsequent differentiation into myofibroblasts, and also increases cell motility in the scratch-test [1, 2]. In this study, we examine a possible role of CD44, a hyaluronic acid receptor, in the activation of fibroblasts with TEKKRRETVEREKE tetradecapeptide (TDP). By CRISPR-CAS9 technology we knocked out the CD44 mRNA and protein in NIH/3T3 fibroblasts and examined the ability CD44KO fibroblasts to in vitro differentiation and wound healing. It was shown that CD44KO NIH/3T3 fibroblasts fully retain their ability to differentiate under influence of TDP or TgF-β1. We show that TDP- or TgF-β1-induced activation of MAPK-signaling pathway does not depend on CD44. In in vitro “healing” of the damaged cell monolayer (scratch-test), the rate of CD44KO cell movement was significantly increased as compared to the wild type NIH/3T3 fibroblasts. Although TDP increased the rate of healing of the scratched wild-type cell monolayer, it did not affect the motility of CD44KO cells. Thus, a presence of CD44-receptor for extracellular matrix' hyaluronic acid is not necessary for TDP-induced activation of NIH/3T3 fibroblasts.