E1A expression dysregulates IL-8 production and suppresses IL-6 production by lung epithelial cellsReport as inadecuate




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Respiratory Research

, 6:111

First Online: 26 September 2005Received: 16 June 2005Accepted: 26 September 2005

Abstract

BackgroundThe adenoviral protein E1A has been proposed to play a role in the pathophysiology of COPD, in particular by increasing IL-8 gene transcription of lung epithelial cells in response to cigarette smoke-constituents such as LPS. As IL-8 production is also under tight post-transcriptional control, we planned to study whether E1A affected IL-8 production post-transcriptionally. The production of IL-6 by E1A-positive cells had not been addressed and was studied in parallel. Based on our previous work into the regulation of IL-8 and IL-6 production in airway epithelial cells, we used the lung epithelial-like cell line NCI-H292 to generate stable transfectants expressing either E1A and-or E1B, which is known to frequently co-integrate with E1A. We analyzed IL-8 and IL-6 production and the underlying regulatory processes in response to LPS and TNF-α.

MethodsStable transfectants were generated and characterized with immunohistochemistry, western blot and flow cytometry. IL-8 and IL-6 protein production was measured by ELISA. Levels of IL-8 and IL-6 mRNA were measured using specific radiolabeled probes. EMSA was used to assess transcriptional activation of relevant transcription factors. Post-transcriptional regulation of mRNA half-life was measured by Actinomycin D chase experiments.

ResultsMost of the sixteen E1A-expressing transfectants showed suppression of IL-6 production, indicative of biologically active E1A. Significant but no uniform effects on IL-8 production, nor on transcriptional and post-transcriptional regulation of IL-8 production, were observed in the panel of E1A-expressing transfectants. E1B expression exerted similar effects as E1A on IL-8 production.

ConclusionOur results indicate that integration of adenoviral DNA and expression of E1A and E1B can either increase or decrease IL-8 production. Furthermore, we conclude that expression of E1A suppresses IL-6 production. These findings question the unique role of E1A protein in the pathophysiology of COPD, but do not exclude a role for adenoviral E1A-E1B DNA in modulating inflammatory responses nor in the pathogenesis of COPD.

AbbreviationsAP-1Activator Protein-1

C-EBPCAAT-Enhancer Binding Protein

ILInterleukin

NFκBNuclear Factor κB

TNFTumor Necrosis Factor

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Author: Arjen van den Berg - Mieke Snoek - Henk M Jansen - René Lutter

Source: https://link.springer.com/



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