Cigarette smoking induces an elastolytic cysteine proteinase in macrophages distinct from cathepsin L
| Autor: | R W Mason, P Chen, L. Z. Sailor, Harold A. Chapman, D. Wilcox, John J. Reilly |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Pulmonary and Respiratory Medicine
Physiology Cathepsin L Cathepsin O Antigen Reference Values Physiology (medical) Cathepsin L1 Endopeptidases medicine Humans Macrophage RNA Messenger Cathepsin Pancreatic Elastase biology Chemistry Macrophages Smoking Cell Biology Cathepsins Molecular biology Actins Pulmonary Alveoli Cysteine Endopeptidases medicine.anatomical_structure Biochemistry biology.protein Pulmonary alveolus Bronchoalveolar Lavage Fluid Cysteine |
| Zdroj: | American Journal of Physiology-Lung Cellular and Molecular Physiology. 261:L41-L48 |
| ISSN: | 1522-1504 1040-0605 |
| DOI: | 10.1152/ajplung.1991.261.2.l41 |
| Popis: | Degradation of the interstitium of the lung by elastolytic enzymes is thought to be a critical component of the pathogenesis of emphysema. Alveolar macrophages are increased in numbers in cigarette smokers and contain the elastolytic cysteine proteinase cathepsin L. We sought to determine if cigarette smoking induces a change in cathepsin L levels in alveolar macrophages which would, in turn, alter the expression of elastolytic activity. Lysates of smokers' macrophages, assayed at pH 5.50, degraded more than seven times as much [3H]elastin as did lysates from nonsmokers' macrophages (44 +/- 20.8 vs. 6 +/- 1.6 micrograms.10(6) cells-1.24 h-1). Little or no activity was demonstrable at neutral pH. Immunoblots of macrophage lysates demonstrated that smokers' cells contain 3.7 +/- 1.1 times as much 25-kDa cathepsin L antigen as nonsmokers' cells. However, as judged by active site labeling, levels of active cathepsin L in smokers and nonsmokers are indistinguishable, suggesting that most of the 25-kDa antigen found in smokers' macrophages is inactive. Inhibitors of cathepsin L had little effect on lysate elastolytic activity, confirming that an enzyme other than cathepsin L is responsible for the increased elastolytic activity seen in smokers' macrophages. Further experiments demonstrated that this second enzyme(s) has a profile of inhibition indicating that it is a cysteine proteinase with optimal activity at pH 5.50. It is this second elastolytic cysteine proteinase(s) that is induced by exposure to cigarette smoke and is responsible for the sevenfold increase in elastolytic activity found in smokers' macrophage lysates. |
| Databáze: | OpenAIRE |
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