Vitamin adeficiency and keratin biosynthesis in cultured hamster trachea |
| |
Authors: | Freesia L Huang Dennis R Roop Luigi M De Luca |
| |
Institution: | (1) Laboratory of Cellular Carcinogenesis and Tumor Promotion, National Cancer Institute, National Institutes of Health, 20892 Bethesda, Maryland |
| |
Abstract: | Summary Tracheas from vitamin A-deficient hamsters in organ culture in vitamin A-free medium developed squamous metaplasia. Addition
of retinyl acetate to the medium prevented squamous metaplasia and a mucociliary epithelium was maintained. Indirect immunofluorescent
staining with antikeratin antibodies AE1 and AE3 indicated positive reactions with epithelium of tracheas either cultured
in vitamin A-free or retinyl acetate (RAc)-containing medium. The “stratum corneum”-like squames in metaplastic tracheas were
strongly stained by AE3.
Immunoprecipitation of cytoskeletal extracts from 35S]methionine labeled tracheas with a multivalent keratin antiserum indicated that the concentration of keratins synthesized
in tracheas cultured in vitamin A-free medium was greater than that observed in tracheas cultured in the presence of RAc.
In addition, new species of keratin were expressed in tracheas cultured in RAc-free medium. Alterations in the program of
keratin synthesis were clearly detectable after 1 d in vitamin A-free medium, even though squamous metaplasia was not yet
obvious. Squamous tracheas were shown by immunoblot analysis to contain keratins of 50, 48, 46.5, and 45 kilodalton (kd) detected
with AE1; and 58, 56, and 52 kd detected with AE3. Immunoblot analysis with monospecific antimouse keratin sera also demonstrated
the presence of 60, 55, and 50 kd keratins in the metaplastic tracheas. All these various species of keratins were either
absent or present in much reduced quantity in mucociliary tracheas in RAc-containing medium. Interestingly, the induction
of squamous metaplasia in tracheal epithelium did not result in the expression of the 59 and 67 kd keratins which are characteristically
expressed in the differentiated layers of the epidermis.
Therefore, this study shows that squamous metaplasia of tracheas due to vitamin A-free cultivation is accompanied by an increase
in keratin synthesis as well as by the appearance of keratin species not normally present in mucociliary tracheal epithelium. |
| |
Keywords: | tracheas keratins squamous metaplasia vitamin A deficiency |
本文献已被 SpringerLink 等数据库收录! |
|