Divergent regulation of 92-kDa gelatinase and TIMP-1 by HBECs in response to IL-1beta and TNF-alpha.
In this study, we addressed the question of whether human bronchial epithelial cells (HBECs) contribute to the regulation of 92-kDa gelatinase activity by secreting tissue inhibitor of metalloproteinase (TIMP)-1. We investigated expression of 92-kDa gelatinase and TIMP-1 in response to lipopolysaccharide (LPS) and to the proinflammatory cytokines interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha. Confluent HBECs from explants were cultured in plastic dishes coated with type I and III collagen. We demonstrated that TIMP-1 was expressed at both the protein and mRNA levels by primary cultures of HBECs. Gelatin zymography of HBEC-conditioned media showed that exposure of HBECs to LPS, IL-1beta, or TNF-alpha induced a twofold increase in the latent form of 92-kDa gelatinase production, as well as its activation. Also, quantitative reverse transcriptase (RT)-polymerase chain reaction (PCR) demonstrated a twofold increase in the 92-kDa mRNA level in response to both cytokines. In contrast, TIMP-1 production evaluated by immunoblotting was unchanged in the presence of LPS and IL-1beta and was clearly decreased in the presence of TNF-alpha. Quantitative RT-PCR demonstrated that TIMP-1 mRNA levels remained unchanged in response to LPS or IL-1beta but decreased by 70% in the presence of TNF-alpha. All of these results strongly suggest that the control mechanisms regulating the expression of 92-kDa gelatinase and TIMP-1 by HBECs in response to inflammatory stimuli are divergent and result in an imbalance between 92-kDa gelatinase and TIMP-1 in favor of the metalloproteinase. Such an imbalance may contribute significantly to acute airway inflammation.
Yao
P M
PM
Institut National de la Santé et de la Recherche Médicale Unité U296 and Département de Physiologie, Faculté de Médecine, Créteil, France.
Maitre
B
B
Delacourt
C
C
Buhler
J M
JM
Harf
A
A
Lafuma
C
C
D001940:Breast; D001980:Bronchi / Q000378:metabolism*; D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D018093:Gelatinases / Q000096:biosynthesis*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D016676:Macrophages, Alveolar / Q000378:metabolism / Q000473:pathology; D008970:Molecular Weight; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D012128:Respiratory Distress Syndrome / Q000378:metabolism / Q000473:pathology; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000096:biosynthesis*; D014158:Transcription, Genetic / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D017077:Culture Media, Conditioned; D007375:Interleukin-1; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1; D014409:Tumor Necrosis Factor-alpha; D018093:Gelatinases