Effects of Food-Derived Collagen Peptides on the Expression of Keratin and Keratin-Associated Protein Genes in the Mouse Skin

Abstract

Oral ingestion of collagen peptides (CP) has long been suggested to exert beneficial effects on the skin, but the molecular events induced by CP on the skin remain unclear. Here, we investigated the effects of oral CP administration on gene expression in hairless mouse skin and of prolyl-hydroxyproline (Pro-Hyp), a collagen-derived dipeptide, on gene expression in a coculture of mouse skin keratinocytes and fibroblasts. Using microarray analysis, we found that oral administration of CP to hairless mice for 6 weeks induced increased expression of Krtap and Krt genes in the skin. Annotation analysis using DAVID revealed that a group of the up-regulated genes, Gprc5d, Sprr2a1, Krt27 and Krtap16-7, is associated with the development of the epidermis and the hair cycle. In addition, the presence of Pro-Hyp (200 μ<smlcap>M</smlcap>) induced an increase in the expression of Krtap16-7, Krtap15, Krtap14 and Krtap8-2 in keratinocytes in coculture, partially resembling the in vivo result. The Pro-Hyp-induced up-regulation of these genes was not observed when keratinocytes were cultured without fibroblasts, suggesting that the presence of fibroblasts is essential for the effects of Pro-Hyp. Our study presents new insights into the effects of CP on the skin, which might link to the hair cycle.

Ingestion of bioactive collagen hydrolysates enhance facial skin moisture and elasticity and reduce facial ageing signs in a randomised double-blind placebo-controlled clinical study

“…Okawa et al suggested that induced hyaluronic acid in dermal fibroblasts followed by oral administration of collagen hydrolysate may provide beneficial effects on maintaining epidermal and dermal homeostasis in mice. Additionally, Le Vu et al demonstrated that Pro‐Hyp induced an increase in expression of Krtap and Krt genes in keratinocytes in co‐culture with fibroblasts. These findings suggest that Pro‐Hyp may affect signalling to change the phenotype of keratinocytes through the regulation of dermal cells.…”

Oral supplementation with specific bioactive collagen peptides improves nail growth and reduces symptoms of brittle nails

“…When administered orally, BCP are absorbed in the form of small collagen peptides and free amino acids . Free amino acids provide building blocks for the formation of dermal extracellular matrix proteins and for the epidermal structure, whereas collagen peptides act as bioactive messengers, activating different signaling pathways and stimulating dermal and epidermal metabolism . Hence, clinical improvements in brittle nails symptoms observed in the present study may not only be a consequence of the protein intake, but also due to the stimulatory effects of specific collagen peptides on epidermal and dermal metabolism.…”

“…The formation of the nail plate requires epidermal proliferation and nail matrix differentiation . Le Vu et al revealed that collagen peptides supplementation was associated with the development of the epidermis with a 5.3‐fold enrichment. It does so by upregulating genes such as Gprc, Krt, and Krtap, which code for structural components of epidermis and skin appendages such as hair, hair follicles, and nails.…”

G-CSF Administration Accelerates Cutaneous Wound Healing Accompanied With Increased Pro-Hyp Production In db/db Mice

“…It has been shown that the growth of cultured dermal fibroblasts is stimulated by Pro-Hyp [24,33], and that keratin gene expression in keratinocytes cocultured with fibroblasts is also increased by the addition of Pro-Hyp [34]. In addition, osteoblastic differentiation of MC3T3-E1, accompanied by an increase in Runx2 and Col1a1 gene expression, is induced by Pro-Hyp [35].…”