Abstract
Purpose: :
Both of corneal and conjunctival epithelia are of surface ectodermal origin as well as epidermis. However ocular surface epithelia usually are not keratinized, it is known that keratinization occurs on corneal and conjunctival epithelia in some pathological conditions such as inflammation and desiccation. The aim of this study was to examine if lacrimal gland epithelial cells of the same ectodermal origin were keratinized or trans-differentiated to other epithelial tissues, in vitro.
Methods: :
Lacrimal gland epithelial cells were obtained from 0-4 day-old C57BL/6 mice and cultured in the following conditions, A-E. (A, B) Cultured in CnT-07 medium (progenitor cell targeted (PCT) medium for epidermal keratinocytes) for 1 week, then replated on Matrigel and cultured with CnT-07 medium for further 1 week with (A) or without SU5402 (B), an inhibitor of fibroblast growth factor receptor. (C) Cultured in CnT-07 medium for 1 week, then on Matrigel with CnT-22 medium (mammary epithelium medium) for further 1 week. (D, E) Cultured in CnT-07 medium (D) or in CnT-57 medium (another PCT medium for epidermal keratinocytes) (E) for 1 week, then air-lifted in CnT-02 medium (epidermal keratinocyte 3D prime medium). Tissues after culture in above conditions were examined immunohistochemically using differentiation markers for cornea, skin and some other epithelial tissues.
Results: :
Mouse lacrimal gland epithelial cells formed concentric stratified epithelial spheres with keratinized cores when cultured in condition (A), while keratinization was suppressed by the administration of SU5402 (B). In both culture products, skin differentiation marker filaggrin and corneal epithelial marker cytokeratin 12 were positive in stratified cells. When cultured in condition (C), keratinization was suppressed but instead stratified layers were thickened. By air-lifting, keratinized stratified epithelial tissue resembling epidermis (D) or non-keratinized stratified epithelial tissue similar to corneal epithelium (E) were formed, depending on the culture media before air-lifting.
Conclusions: :
Newborn mouse lacrimal gland epithelial cells have potency to differentiate to epidermis- or cornea-like epithelia. Now we are to analyze the molecular mechanisms of this transdifferentiation of mouse lacrimal gland epithelial cells.
Keywords: lacrimal gland • differentiation • development