Purpose: We aimed to determine if German cockroach extract (GCE) can activate MMPs and then, GCE-stimulated MMPs influence tight and adherence junction in airway epithelial cells.
Methods: The mRNA and protein levels of MMPs were assessed by quantitative PCR and enzyme linked immunosorbent assay in human airway epithelial cells cultured in the presence of German cockroach extract. Immunoblotting and immunofluorescent staining were performed for identifying airway epithelial integrity and the structure of intercellular junction. Transepithelial resistance was measured to determine epithelial barrier function.
Results: GCE significantly increased MMP-1 and MMP-9 mRNA and protein in airway epithelial cells. This extract also attenuated the integrity of ZO-1 and Occludin protein, and induced epithelial ZO-1 and Occludin delocalization profoundly. In addition, prolonged exposure to GCE decreased significantly epithelial resistance. These GCE-induced degradations were dramatically prohibited by a MMP inhibitor known as a potent inhibitor of collagenases.
Conclusion: This study shows that GCE-activated MMP-1 and MMP-9 can alter junctional proteins and epithelial barrier function, thereby facilitating stimuli penetration.