Extracellular matrix metalloproteinase inducer (EMMPRIN), a glycosylated transmembrane
protein that induces
matrix metalloproteinases (
MMPs), is minimally expressed in the normal adult lung. We previously reported that it is up-regulated in murine
bleomycin-induced
lung injury. In this study, we determined the expression of
EMMPRIN and its association with MMP-2, MMP-7, and MMP-9 in
interstitial pneumonias (IPs). We performed immunohistochemistry for
EMMPRIN and
MMPs on lung tissue from 22 subjects with various IPs. We did bronchoalveolar lavage (BAL) on 9 of these subjects and 13 others with IPs to measure the soluble
EMMPRIN in BAL fluid. For comparison, immunohistochemistry or BAL was done on 14 subjects without IPs. The staining intensity for each
protein was scored from 0 to 3 in various epithelial cell types. Soluble
EMMPRIN in BAL fluid was measured by an
enzyme-linked
immunosorbent assay. Extracellular matrix
metalloproteinase inducer was prominent in abnormal epithelial cells. It was more prominent in hyperplastic type II cells, compared with epithelium in alveolar bronchiolization. It was also elevated in BAL fluid from the subjects with IPs.
Matrix metalloproteinases were expressed in cells expressing
EMMPRIN, although the profile of
MMPs varied among the different abnormal epithelial cell types with MMP-2 and MMP-7 in hyperplastic type II cells and MMP-7 and MMP-9 in cells showing squamous
metaplasia and cells comprising bronchiolization. These results suggest a role of
EMMPRIN in reepithelialization in IPs.