Intrinsic regulation of differentiation markers in human epidermis, hard palate and buccal mucosa

Different epithelia show extensive variation in differentiation. Epidermis and epithelium from the hard palate are both typical examples of orthokerat inized epithelia whereas buccal mucosa is an example of a non-keratinized e pithelium. Each of these tissues can be distinguished morphologically and a lso by the expression of a number of structural proteins. Tissue explants d erived from epidermis, hard palate or buccal mucosa were cultured at the ai r-liquid interface on collagen gels containing human dermal fibroblasts. Re constructed epithelia that retained many of the morphological and immunohis tochemical characteristics of the original tissue were formed. Cultures der ived from epidermis and the hard palate both had a well-defined stratum bas ale, stratum spinosum, stratum granulosum and stratum corneum whereas cultu res derived from buccal mucosa had no stratum granulosum or corneum and the cells retained their nuclei. Significantly more living cell layers were ob served in both types of epithelia obtained from the mouth than in epidermis . The specific localization of proliferation and differentiation markers (K i67, loricrin, involucrin, SPRR2, SPRR3 and keratin 10) closely resembled t hat of the tissue from which the cultures were derived. As identical three- dimensional culture models were used here, it is concluded that the differe nces observed between these epithelia were due to intrinsic properties of t he keratinocytes. (C) 2000 Elsevier Science Ltd. All rights reserved.