Regulation of GATA-3, c-maf and T-bet mRNA expression in bronchoalveolar lavage cells and bronchial biopsies after segmental allergen challenge.
BACKGROUND
GATA-3 (GATA binding protein 3) and the proto-oncogene c-maf are Th2-regulating transcription factors that control the expression of interleukin (IL)-4 and IL-5, while T-bet (T-box expressed in T cells) is a Th1-specific transcription factor that controls the expression of interferon (IFN-gamma). Allergen provocation in asthmatics induces a Th2-dominated cytokine profile, but so far it is unknown whether the skewed cytokine expression is reflected by the expression of the respective transcriptional regulators.


OBJECTIVE
The aim of this study was to determine the regulation of Th1- and Th2-specific transcription factors and cytokines in 10 atopic subjects with mild asthma and 5 nonatopic healthy controls at baseline and after segmental sham and allergen challenge.


METHODS
The mRNA expression of GATA-3, c-maf and T-bet was determined by real-time polymerase chain reaction in bronchoalveolar lavage (BAL) cells and bronchial biopsies. The percentage of IL-4+, IL-5+ and IFN-gamma+ BAL T cells was determined by flow cytometry, and BAL levels of these cytokines were measured by ELISA.


RESULTS
In BAL cells of asthmatics, the mRNA expression of all transcription factors was increased after allergen challenge. In bronchial biopsies, the basal expression of GATA-3 was increased in asthmatics compared to healthy controls but decreased after allergen challenge. Compared to sham challenge, the percentage of IL-5+/CD4+ BAL T cells was increased after allergen challenge in asthmatics while the percentage of IFN-gamma+/CD4+ and IFN-gamma+/CD8+ T cells was decreased. Expression of c-maf mRNA in BAL cells correlated with IL-4+/CD4+ BAL cells and BAL IL-5 levels.


CONCLUSIONS
Segmental allergen challenge in asthmatics leads to increased GATA-3, c-maf and T-bet expression in BAL cells but not in bronchial biopsies.
Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany. erpenbeck@item.fraunhofer.de
Veit J
VJ
Erpenbeck
Andreas
A
Hagenberg
Harald
H
Krentel
Marc
M
Discher
Armin
A
Braun
Jens M
JM
Hohlfeld
Norbert
N
Krug
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000008:administration & dosage / Q000276:immunology*; D001249:Asthma / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D001706:Biopsy; D001980:Bronchi / Q000276:immunology / Q000378:metabolism*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D005260:Female; D050990:GATA3 Transcription Factor / Q000235:genetics*; D005786:Gene Expression Regulation; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D015848:Interleukin-5 / Q000378:metabolism; D018655:Lymphocyte Count; D008297:Male; D000090063:Proto-Oncogene Mas; D051257:Proto-Oncogene Proteins c-maf / Q000235:genetics*; D012333:RNA, Messenger; D020825:T-Box Domain Proteins; D016176:T-Lymphocyte Subsets / Q000276:immunology; D014157:Transcription Factors / Q000235:genetics*; D000098815:T-bet Transcription Factor
D000485:Allergens; D050990:GATA3 Transcription Factor; C508598:IL4 protein, human; C508599:IL5 protein, human; D015848:Interleukin-5; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D051257:Proto-Oncogene Proteins c-maf; D012333:RNA, Messenger; D020825:T-Box Domain Proteins; D000098815:T-bet Transcription Factor; D014157:Transcription Factors; D015847:Interleukin-4; D007371:Interferon-gamma