Adenovirus E1A regulates lung epithelial ICAM-1 expression by interacting with transcriptional regulators at its promoter.
We focused on the regulation of inflammatory mediator expression by adenovirus E1A in lung epithelial cells and the role of this viral protein in the pathogenesis of chronic obstructive pulmonary disease (COPD). We previously reported that E1A, a well-known regulator of host genes, increased ICAM-1 expression in human bronchial epithelial (HBE) and A549 cells in response to LPS stimulation. In this report, we clarified the mechanism of this regulation. We found NF-kappaB translocation to the nucleus after LPS stimulation in both E1A-positive and -negative HBE cells. ICAM-1 promoter reporter constructs revealed that a mutation in the proximal NF-kappaB binding site completely inhibited increased transcription, whereas the mutation in a distal site did not. We analyzed the participation of E1A in transcriptional complex formation at this promoter using chromatin immunoprecipitation. In E1A-positive HBE and A549 cells, LPS stimulation increased ICAM-1 promoter immunoprecipitation by NF-kappaB p65 and p300 but not activator protein-1 antibodies with a concomitant increase by the E1A antibody. No increase was found in E1A-negative cells except in HBE cells with p65 antibody. The association of E1A with the increased promoter immunoprecipitation with p300 was also observed after TNF-alpha stimulation of A549 cells. These results suggest that adenovirus E1A regulates the ICAM-1 promoter through its proximal NF-kappaB binding site, most likely by interacting with the transcriptional complex that forms at this site. E1A regulation of the LPS response may play a role in acute exacerbations as a consequence of bacterial infections in COPD.
Morimoto
Kiyoshi
K
The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, St Paul's Hospital, University of British Columbia, Vancouver, Canada.
Gosselink
John
J
Kartono
Aileen
A
Hogg
James C
JC
Hayashi
Shizu
S
Ogawa
Emiko
E
D000256:Adenoviridae / Q000235:genetics* / Q000472:pathogenicity; D017500:Adenovirus E1A Proteins / Q000235:genetics* / Q000502:physiology; D001424:Bacterial Infections / Q000150:complications; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D001980:Bronchi / Q000166:cytology / Q000378:metabolism; D002460:Cell Line; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D017930:Genes, Reporter; D054884:Host-Pathogen Interactions / Q000235:genetics; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics*; D008070:Lipopolysaccharides / Q000633:toxicity; D008156:Luciferases / Q000235:genetics; D008168:Lung / Q000166:cytology / Q000378:metabolism*; D009154:Mutation; D016328:NF-kappa B / Q000378:metabolism; D011401:Promoter Regions, Genetic; D029424:Pulmonary Disease, Chronic Obstructive / Q000209:etiology; D050436:Regulatory Elements, Transcriptional; D051197:Toll-Like Receptor 4 / Q000235:genetics; D015533:Transcriptional Activation
D017500:Adenovirus E1A Proteins; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D016328:NF-kappa B; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; C440499:lipopolysaccharide, Escherichia coli O111 B4; D018799:Intercellular Adhesion Molecule-1; D004247:DNA; D008156:Luciferases