Downregulation of a disintegrin and metalloproteinase 33 by IFN-gamma in human airway smooth muscle cells.
BACKGROUND
A disintegrin and metalloproteinase 33 (ADAM33) has been identified as a susceptibility gene for asthma. ADAM33 is expressed in airway smooth muscle (ASM) cells and is suggested to play a role in the function of these cells. However, there is little information on the regulation of ADAM33.


OBJECTIVE
To investigate whether ADAM33 is more highly expressed in ASM cells of patients with asthma than in those of normal subjects, and whether there is any inflammatory mediator (asthma-related cytokine/chemokine) that could modulate the expression of ADAM33 in ASM cells.


METHODS
smRNA and protein expression of ADAM33 in bronchial biopsy specimens was investigated (in situ hybridization and immunohistochemistry). Effects of cytokines on expression of ADAM33 in cultured human ASM cells were evaluated by measuring mRNA (real-time RT-PCR) and protein (Western blotting).


RESULTS
ADAM33 mRNA and protein in biopsied specimens were more highly expressed in ASM cells of patients with asthma than in cells of normal subjects. Cultured ASM cells expressed ADAM33 at both the mRNA and the protein levels. IFN-gamma reduced the mRNA expression dose-dependently and time-dependently, whereas IL-4 and IL-13 or chemokines did not affect the expression. The reduction by IFN-gamma was partially restored by U0126, inhibitor for mitogen-activated protein kinase kinase 1/2, suggesting a role for extracellular signal-regulated kinase pathway. Further studies using cycloheximide and actinomycin-D suggested that the downregulation was at the transcriptional level.


CONCLUSIONS
The expression of ADAM33 by ASM cells is increased in patients with asthma, and its expression may be regulated by IFN-gamma.


CONCLUSIONS
IFN-gamma might have a role in suppressing ADAM33 in ASM cells.
Ito
Isao
I
Meakins-Christie Laboratories, McGill University, Montreal, Quebec, Canada, H2X 2P2.
Laporte
Johanne D
JD
Fiset
Pierre O
PO
Asai
Kazuhisa
K
Yamauchi
Yasuhiro
Y
Martin
James G
JG
Hamid
Qutayba
Q
D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism*; D001249:Asthma / Q000378:metabolism*; D001980:Bronchi / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D015536:Down-Regulation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D018793:Interleukin-13 / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000378:metabolism; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology
D018793:Interleukin-13; D020033:Protein Isoforms; D012333:RNA, Messenger; D015847:Interleukin-4; D007371:Interferon-gamma; D048049:Extracellular Signal-Regulated MAP Kinases; D051722:ADAM Proteins; C450441:ADAM33 protein, human