Expression and distribution of the intermediate filament protein nestin and other stem cell related molecules in the human olfactory epithelium

Abstract

The olfactory epithelium (OE) is unique inregenerating throughout life and thus is an attractivetarget for examining neurogenesis. The nestin proteinwas shown to be expressed in the OE of rodents and issuggested to be essentially involved in the process ofregeneration. Here we report the expression anddistribution of nestin in the human OE at RNA andprotein level. Moreover, we analysed the expressionprofiles in dependence on age and olfactory capacity.After sinus surgery, biopsies were taken from theolfactory epithelium of 16 patients aged 20-80 yearswith documented differences in their olfactory function.Our studies revealed that nestin is constantly detectablein the apical protuberances of sustentacular cells withinthe human OE of healthy adults. Its expression is notdependent on age, but rather appears to be related to theolfactory function, as a comparison with specimensobtained from patients suffering either from persistentanosmia or hyposmia suggests. Particularly, in thecourse of dystrophy, often accompanied with impairedolfaction, nestin expression was occasionally decreased.Contrarily, the expression of the p75-NGFR protein, amarker for human OE basal cells, was not altered,indicating that at least in the tested samples olfactoryimpairment is not connected with abnormalities at thebasal cell level. These observations emphasize anessential role of nestin for the process of regeneration,and also highlight this factor as a candidate marker forsustentacular cells in the human olfactory epithelium