Development and Characterization of 3D Senescent Models Mimicking Skin Aging

Aging, marked by a decline in cellular function and increased risk of diseases, involves the accumulation of senescent cells. This study aims to develop and characterize 3D senescent skin models to understand cellular senescence mechanisms’ implications in cutaneous aging. Normal human epidermal keratinocytes (NHEKs) were cultured from early to late passages (p2 to p7) to induce replicative senescence or sourced from both young and aged donors to reconstruct 3D models. Histological analyses assessed tissue morphology and integrity, while permeability assays evaluated epidermal barrier function. Analyses using immunostaining, RT-PCR, Affymetrix™ GeneChip™ Microarrays identified key markers of cellular senescence, epidermal homeostasis, and other related processes. Results showed that NHEKs at p5 and beyond, and those from aged donors, exhibited significant morphological disruptions, decreased expression of differentiation-associated genes, and impaired barrier function. Increased p16ink4a-positive cells indicated enhanced senescence. Transcriptome analysis revealed significant changes in keratinocyte differentiation, cell–cell interaction, cell cycle regulation, extracellular matrix homeostasis, and inflammation. These findings underscore the relevance of addressing cellular senescence for enhancing skin health and promoting skin longevity. These 3D senescent skin models, validated by consistent results from both passage-induced senescence and aged donor keratinocytes, are valuable for understanding skin aging and developing anti-aging treatments, positioning them as essential tools in the pursuit of skin longevity-focused innovations.