Collagenase expression by normal human eosinophils

Abstract

Collagenolytic activity was detected in extracts from human blood eosinophilic granulocytes. To characterize this collagenase, we compared extracts from isolated populations of eosinophils and neutrophils. Significant collagenase activity against type I and II collagens was present in extracts from both cell populations. Although collagenase activity was present in eosinophils, the cells did not stain with antibodies specific for fibroblast, neutrophil collagenase, or collagenase-3. In contrast, neutrophils immunostained positively with antibody to neutrophil collagenase. Western blot analysis confirmed the presence of immunoreactive protein in neutrophil extracts but not in the eosinophil extracts. Reverse transcription-polymerase chain reaction using primers specific for all three known collagenases of an eosinophil cell suspension from peripheral blood that had 3% contamination with immature neutrophils showed a polymerase chain reaction product only with neutrophil collagenase oligonucleotide primers, but not with fibroblast collagenase or collagenase-3 primers. Eosinophil collagenase would appear to have a unique antigenic structure and may represent a new enzyme.

Collagenolytic Activity in Bronchoalveolar Lavage Fluid in Canine Pulmonary Eosinophilia

“…Despite the negative staining of eosinophils with MMP-8 and MMP-13 antibodies, the significant positive correlation found between the eosinophil cell count and the percentage of degraded collagen I suggests that eosinophils participate in type I collagen degradation. This concept is in agreement with the recent findings by Shlopov and Hasty, 18 who found human blood eosinophils to be neg- ative for immunostaining with MMP-8, MMP-13, and MMP-1 antibodies. However, the blood eosinophil extract degraded collagens I and II in a manner closely resembling the action of classic interstitial collagenases (MMP-1, MMP-8, and MMP-13).…”

“…11,12 MMP-1 has not been detected in human blood eosinophils by immunostaining. 18 The correlation analysis between the percentage of degraded collagen I in BALF and BALF cellular counts provides indirect support that eosinophils can be sources of collagenolytic activity, whereas neutrophils seem to have minor importance. Despite the negative staining of eosinophils with MMP-8 and MMP-13 antibodies, the significant positive correlation found between the eosinophil cell count and the percentage of degraded collagen I suggests that eosinophils participate in type I collagen degradation.…”

“…Previous studies also have not detected MMP-8 immunoreactivity from eosinophils. 18 Until recently, MMP-8 has been regarded as a neutrophil-specific enzyme. However, Prikk et al 9 have reported MMP-8 protein and messenger RNA expression in pulmonary monocytes/macrophages, bronchial epithelial cells, and glandular cells.…”

“…However, the blood eosinophil extract degraded collagens I and II in a manner closely resembling the action of classic interstitial collagenases (MMP-1, MMP-8, and MMP-13). 18 MMP-2 and MMP-14 also can degrade type I and II collagens, much like interstitial collagenases. 16,17 Shlopov and Hasty 18 suggested that eosinophils produce an unknown enzyme with collagenolytic activity, and this possibility exists also in PE dogs' BALF eosinophils.…”

“…16,17 However, human blood eosinophils have been suggested to contain their own distinct collagenolytic enzyme activities. 18 In our previous study of gelatinolytic MMP-2 and MMP-9 in canine PE, we discussed the possible role of MMP-9 in the pathogenesis of PE. 1 However, MMP-9 was mainly found in BALF macrophages and epithelial cells and not in the major cell type (ie, eosinophils).…”