Abstract
Purpose: :
To investigate the plasticity of mouse vibrissal hair follicle stem cells regarding differentiation into corneal epithelial cells through modulation of limbus-specific microenvironmental factors.
Methods: :
Hair follicles containing multipotent stem cells were isolated from 3-5 weeks old mouse pups. Dissociated cells from the bulge region were enriched for stem and progenitor cell population by clonal growth on 3T3 feeder cells and subcultivated on various extracellular matrices (collagen type IV, laminin-1, laminin-5, fibronectin) in DMEM/F12 medium supplemented with different conditioned media. Conditioned media were harvested from cultured human fibroblasts derived from central cornea, peripheral cornea and limbal stroma as well as from 3T3 fibroblasts. Growth potential and cellular phenotype were evaluated by light and electron microscopy and immunohistochemistry using antibodies against epidermal progenitor cell markers (CK15) and differentiation markers characteristic for corneal epithelium (CK12) or epidermis (CK10).
Results: :
Laminin-5, a major component of the corneal and limbal basement membrane zone, and collagen type IV promoted rapid cell adhesion, proliferation, and generation of confluent, regularly arranged epitheloid cell sheets, whereas laminin-1 and fibronectin adversely affected cell adhesion and growth. Addition of conditioned media differentially influenced cellular phenotype and differentiation. Medium derived from limbal fibroblasts induced the differentiation of cuboid cells showing ultrastructural characteristics of a corneal epithelial phenotype. Moreover, it markedly increased the number of CK15 and CK12-immunopositive cells while decreasing expression of CK10 in cultivated cell sheets as compared to the other conditioned media and unconditioned controls.
Conclusions: :
These findings suggest that hair follicle stem cells are capable of differentiating into corneal epithelial-like cells in vitro when exposed to a limbus-specific microenvironment. Therefore, the hair follicle may be an alternative therapeutic source of multipotent stem cells for the generation of autologous epithelial cell sheets for ocular surface reconstruction.
Keywords: cornea: epithelium • differentiation • cornea: basic science