Regulation of extracellular matrix (ECM) components is essential for tissue homeostasis and function. We screened a small peptide that induces ECM protein synthesis for its usefulness in protecting keratinocytes. In this report, we demonstrate that myristoyl tetrapeptide Ala-Ala-Pro-Val (mAAPV) stimulates the expression of ECM proteins and inhibits the expression of metalloproteinases (MMPs) that degrade ECM proteins in Hs68 human fibroblast cells. In order to elucidate the underlying molecular mechanisms for the effects of mAAVP, we investigated the changes in gene expression in the presence of mAAPV using a cDNA microarray. Treatment with mAAPV resulted in decreased expression of MMP-related genes such as MMP1, MMP3, TIMP1 and TIMP3 and increased expression of collagen genes, including COL1A1, COL1A2, COL3A1, COL5A1 and COL6A3. The pattern of gene expression regulated by mAAPV was very similar to that of gene expression induced by transforming growth factor (TGF)-β, indicating that the TGF-β signaling pathway is crucial for simultaneous activation of several ECM-related genes by mAAPV. We examined whether the activation of SMAD, a downstream protein of TGF-β receptor, is involved in the signal transduction pathway induced by mAAPV. The results demonstrate that mAAVP directly activates SMAD2 and induces SMAD3 to bind to DNA. In conclusion, our results demonstrate that mAAPV both enhances the expression of collagen and inhibits its degradation via production of protease inhibitors that prevent enzymatic breakdown of the ECM. The results suggest that mAAPV would be a useful ECM-protecting agent.

Palmitoyl tripeptide (M330) showed higher antimicrobial activities than methyl paraben or phenoxy ethanol through minimum inhibitory concentration (MIC) test. However, when the M330 was added into cosmetic formulation, white precipitates formed due to the electrostatic interaction between M330 and carbopol (carboxy vinyl polymer) as a thickener in cosmetics, and the viscosity of cosmetics decreased sharply. Also, the antimicrobial activities of M330 in cosmetics became lower than those of methyl paraben or phenoxy ethanol. Thus, the encapsulation of M330 in ethosome vesicle was attempted in order to recover the declined antimicrobial activities of M330 in cosmetics and prevent the precipitates from forming. When ethosome-encapsulated M330 was added into cosmetics, the precipitates did not form, and the decrease in the viscosity of cosmetics was not large compared to the addition of unencapsulated M330. Challenge tests showed that antimicrobial activities against gram negative bacteria were improved by the encapsulation of M330, but the encapsulation was not effective against gram positive bacteria and fungus. A combination of M330 with EDTA showed synergistic inhibitory potential against C. albicans. After coencapsulation of M330 and EDTA in ethosome, antimicrobial activities proved to be higher than those of unencapsulated M330 and EDTA.