Two clonal types of human skin fibroblasts with different potentials for proliferation and tissue remodeling ability.

Background: Skin fibroblast heterogeneity is of growing interest due to its relevance in not only skin development but also cutaneous wound healing. However, the characterization of human dermal fibroblasts at a clonal level has not been accomplished and their functional heterogeneity remains poorly understood.

Objective: The aim of this study was to define the clonal heterogeneity of human dermal fibroblasts.

Methods: Isolated human dermal fibroblasts were clonally expanded and categorized by comprehensive phenotypic and gene expression profiling.

Results: Single fibroblasts were significantly multiplied and efficiently cloned without chromosomal abnormalities under hypoxic conditions. Individual clones were heterogeneous in their proliferative capacity, and gene expression profiling revealed differences in the expression of genes involved in extracellular matrix synthesis and degradation. Each cloned fibroblast also had different abilities in terms of collagen remodeling. All phenotypic and gene expression data were analyzed with Spearman's rank correlation, and fibroblasts were categorized into at least two functional clonal types. One was highly proliferative, while the other was less proliferative but had the ability to remodel the tissue architecture. The proliferative clones were predominant in infants, but decreased with physiological aging.

Conclusion: This study provides strong evidence for the functional heterogeneity of human dermal fibroblasts at a clonal level, which has implications regarding skin repair and aging.