Mechanism of ADAM33 expression regulation in the pathogenesis of IPF.

다국어 초록 (Multilingual Abstract)

ADAM33 has been identifiedas a novel asthma susceptibility gene in genome-wide screening and association studies. Recently, ADAM-33 regarded as lung function gene,not asthma specific. High-level expression in smooth muscles and fibroblasts suggest that ADAM33 plays a rolenot only airway remodeling in asthmatics but may involved fibrosis of lung.
The ADAM33 protein was identified in the BAL fluids of IPF(idiopathic pulmonary fibrosis) and normal controls by western blotting using antibody against the catalytic and cytoplasmic domain. In this analysis of the BAL fluids from the IPFs using ASP2 antibody, an intense band of approximately 70 kDa appeared. And, this band also appeared in the conditioned medium of primary fibroblast from IPF. When the levels of ADAM33 protein in the BAL fluids were measured by dot blotting, theirlevels were increased significantly in UIP and NSIP, as compared to normal control subjects (p= 0.003 and p=0.001, respectively). ADAM33 localization was analyzed using immunohistochemical staining of lung specimens. ADAM33 was expressed in the smooth muscles, interstitium and fibroblastic foci inalmost all the IPF, but was absent in the normal controls.
ADAM33 mRNA expression are regulated by cytokines were shown using RT-PCR. This PCR-amplified product represented at predicted and up-shift size. Interestingly, up-shift product contained intron. This form is an alternative splicing form of ADAM33. More interestingly, most of this alteration is mainly in catalytic domain. IL-13,IL-4 upregulate and making alternative splicing whereas IFN-r inhibit m-RNA expression in catalytic domain. Using western blotting, we confirmed that ADAM33 protein regulated by this cytokines, too. In conclusion, the levels of soluble ADAM33 protein are related to IPF severity and ADAM33 expression are regulated by cytokines such as IL-4, IL-13.