Lab-made human collagen peptide boosts skin-building genes in a filler-style 3D skin model

Collagen loss and matrix disorganization are hallmarks of skin aging, and injectable fillers are a mainstay of aesthetic dermatology. Animal-derived collagen products carry immunogenicity concerns, and orally or topically applied collagen peptides face questions about absorption. Recombinant human collagen (rhCol) peptides, produced by fermentation with sequences identical to human collagen, are proposed as a biocompatible alternative. How they behave once placed in the dermis is poorly understood, partly because human biopsies from filler sites are hard to obtain.

The team, from L'Oréal Research and Innovation in Shanghai, tested an rhCol III peptide matching residues Gly483–Pro512 of human COL3A1. In 2D culture, normal human dermal fibroblasts were treated for 24 hours with the peptide at 100 or 33 μg/mL. Controls were untreated cells and a vitamin C (200 μM) positive control, with triplicate wells. Gene expression was measured by RT-qPCR. They then built a 'filler-mimetic' 3D skin model. Because the thin dermis of reconstructed skin makes consistent injection impractical, the peptide was pre-mixed into the bovine collagen gel containing fibroblasts. Keratinocytes were then seeded on top and cultured at the air–liquid interface. After 22 days, the tissues were assessed by histology, immunostaining (Ki67, COL17A1, fibrillin 1, transglutaminase 1, Alcian blue for glycosaminoglycans) and transcriptomics. FITC-labeled peptide and multiphoton imaging were used to check where the peptide localized relative to the collagen scaffold.

Per the abstract, the peptide significantly upregulated COL1, COL3, elastin, fibrillin 1 and hyaluronic acid synthases 1–3 in fibroblasts. In the 3D model, the peptide bound directly to the dermal scaffold. It was associated with improved epidermal regeneration (higher Ki67 and COL17A1) and dermal remodeling (fibrillin 1 and glycosaminoglycans). Transcriptomic analysis pointed to downregulated inflammation, senescence and apoptosis pathways and upregulated integrin binding and extracellular matrix formation. This suggests the peptide acts as a bioactive scaffold component that signals to both fibroblasts and overlying keratinocytes.

The findings support rhCol III peptides as candidate bioactive filler or cosmetic ingredients, with plausible mechanisms involving integrin-mediated signaling and dermo-epidermal crosstalk. The reduced senescence and inflammation signatures are of interest to those studying skin aging.

The caveats are substantial. The model is not a true injection: the peptide is distributed through the dermis during construction, and the model lacks immune cells, vasculature and mechanical forces. All data are in vitro with a limited cell composition. Authors are employees of the funding company, and the paper itself calls for clinical trials. Only the abstract, introduction and early methods were available to this summary, so exact effect sizes, statistics and the comparators used in the 3D model could not be verified.