| Autor: |
Lag, M., Skarpen, E., Van Rozendaal, B. A. W. M., Haagsman, H. P., Huitfeldt, H. S., Thrane, E. V. |
| Předmět: |
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| Zdroj: |
Experimental Lung Research; Jul/Aug2000, Vol. 26 Issue 5, p383-399, 17p, 11 Black and White Photographs, 7 Graphs |
| Abstrakt: |
CCAAT/enhancer-binding proteins (C/EBP) constitute a family of transcription factors that are involved in regulation of proliferation and differentiation in several cell types. In epithelial lung cells the C/EBPalpha isoform seems to play a role in the regulation of surfactant proteins (SP) and Clara cell specific protein (CCSP), whereas the roles of C/EBPbeta and C/EBP δ are unclear. We have examined the protein levels of C/EBPδ in bronchiolar Clara cells and alveolar type 2 cells, and its relation to the expression of lung speci c proteins and cell proliferation. The protein expression of C/EBPδ was high in freshly isolated Clara cells compared to type 2 cells. In both cell types C/EBPδ levels increased during culture. Alterations of the levels of C/EBPδ did not correspond with the proliferation levels of Clara cells, but seemed to correspond in type 2 cells. Clara cell secretory protein (CCSP) was highly expressed in freshly isolated Clara cells, in contrast to type 2 cells. SP-D and CYP2B1 were expressed at somewhat higher levels in Clara cells than in type 2 cells, whereas SP-A exhibited highest expression in type 2 cells. During culture the levels of all these lung proteins were strongly reduced. However, compared to with serum we found an increase in CCSP in Clara cell cultures without serum, and this correlated with an increase in C/EBPδ. Overall our in vitro data suggest that C/EBP δ alone is not related to the maintenance of proteins involved in differentiation. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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