TY  - JOUR
A1  - Fehrholz, Markus
A1  - Seidenspinner, Silvia
A1  - Kunzmann, Steffen
T1  - Expression of surfactant protein B is dependent on cell density in H441 lung epithelial cells
T2  - PLoS ONE
N2  - Background
Expression of surfactant protein (SP)-B, which assures the structural stability of the pulmonary surfactant film, is influenced by various stimuli, including glucocorticoids; however, the role that cell-cell contact plays in SP-B transcription remains unknown. The aim of the current study was to investigate the impact of cell-cell contact on SP-B mRNA and mature SP-B expression in the lung epithelial cell line H441.

Methods
Different quantities of H441 cells per growth area were either left untreated or incubated with dexamethasone. The expression of SP-B, SP-B transcription factors, and tight junction proteins were determined by qPCR and immunoblotting. The influence of cell density on SP-B mRNA stability was investigated using the transcription inhibitor actinomycin D.

Results
SP-B mRNA and mature SP-B expression levels were significantly elevated in untreated and dexamethasone-treated H441 cells with increasing cell density. High cell density as a sole stimulus was found to barely have an impact on SP-B transcription factor and tight junction mRNA levels, while its stimulatory ability on SP-B mRNA expression could be mimicked using SP-B-negative cells. SP-B mRNA stability was significantly increased in high-density cells, but not by dexamethasone alone.

Conclusion
SP-B expression in H441 cells is dependent on cell-cell contact, which increases mRNA stability and thereby potentiates the glucocorticoid-mediated induction of transcription. Loss of cell integrity might contribute to reduced SP-B secretion in damaged lung cells via downregulation of SP-B transcription. Cell density-mediated effects should thus receive greater attention in future cell culture-based research.
KW  - messenger RNA
KW  - surfactants
KW  - epithelial cells
KW  - transcription factors
KW  - gene expression
KW  - tight junctions
KW  - adenocarcinoma of the lung
KW  - immunoblotting
Y1  - 2017
UR  - https://opus.bibliothek.uni-wuerzburg.de/frontdoor/index/index/docId/15829
UR  - https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-158291
VL  - 12
IS  - 9
ER  -