Effect of Palmitoyl Pentapeptide (Pal KTTKS) on Wound Contractile Process in Relation with Connective Tissue Growth Factor and a Smooth Muscle Actin Expression
To evaluate whether Palmitoyl pentapeptide (Pal KTTKS) a lipidated subfragment of type 1 pro collagen (residues 212 216) plays a role in fibroblast contractility, the effect of Pal KTTKS on the expression of pro fibrotic mediators in hypertropic scarring were investigated in relation with trans differentiation of fibroblast to myofibroblast, an icon of scar formation. a SMA was visualized by immunofluorescence confocal microscopy with a Cy 3 conjugated monoclonal antibody. The extent of a SMA positive fibroblasts was determined in collagen lattices and in cell culture study. Pal KTTKS (0 0.5 uM) induced CTGF and a SMA protein levels were determined by western blot analysis and fibroblast contractility was assessed in three dimensional collagen lattice contraction assay. In confocal analysis, fibroblasts were observed as elongated and spindle shapes while myofibroblast observed as squamous, enlarged cells with pronounced stress fibers. Without Pal KTTKS treatment, three quarters of the fibroblasts differentiates into the myofibroblast; a SMA positive stress fibers per field decreased twofold with 0.1 uM Pal KTTKS treatment (75 7.1 vs 38.6 16.1% n 3, p 0.05) The inhibitory effect was not significant in 0.5 uM Pal KTTKS treatment. Stress fiber level and collagen contractility correlates with a SMA expression level. In conclusion, Pal KTTKS (0.1 uM) reduces a SMA expression and trans differentiation of fibroblasts to myofibroblast. The degree of reduction is dose dependent. An abundance of myofibroblast and fibrotic scarring is correlated with excessive levels of a SMA and collagen contractility. Delicate balance between the wound healing properties and pro fibrotic abilities of pentapeptide KTTKS should be considered for selecting therapeutic dose for scar prevention.
Tissue Engineering and Regenerative Medicine