Abstract
Pyropia yezoensis (P. yezoensis) is a marine algae that exhibits antioxidant, anti-inflammatory, antitumor and anti-aging activities. In this study, we investigated the effects of the P. yezoensis peptide, PYP1‑5, on collagen synthesis in the human dermal fibroblast cell line Hs27. Skin aging is related to reduced collagen production and the activities of multiple enzymes, including matrix metalloproteinases (MMPs), which degrade collagen structure in the dermis, and tissue inhibitor of tissue inhibitor of metalloproteinases (TIMPs), which inhibit the action of MMPs. While collagen synthesis is associated with a number of signaling pathways, we examined the increased collagen synthesis via the upregulation of the transforming growth factor-β (TGF-β)/Smad signaling pathway. Using MTS assay, we found that PYP1‑5 did not affect cell viability. Moreover, we confirmed that PYP1‑5 increased type 1 collagen expression using enzyme-linked immunosorbent assay (ELISA), western blot analysis and quantitative PCR. In addition, we identified changes in various enzymes, as well as the mechanisms behind the PYP1‑5-induced collagen synthesis. PYP1‑5 decreased the MMP-1 protein and mRNA levels, and increased the TIMP-1 and TIMP-2 protein and mRNA levels. In addition, PYP1‑5 activated the TGF-β/Smad signaling pathway, which increased TGF-β1, p-Smad2 and p-Smad3 expression, while inhibiting Smad7, an inhibitor of the TGF-β/Smad pathway. Furthermore, PYP1‑5 upregulated transcription factor specificity protein 1 (Sp1) expression, which is reportedly involved in type 1 collagen expression. These findings indicate that PYP1‑5 activates the TGF-β/Smad signaling pathway, which subsequently induces collagen synthesis in Hs27 cells.