Acute phase mediator oncostatin M regulates affinity of α1-protease inhibitor for concanavalin A in hepatoma-derived but not lung-derived epithelial cells

Quantitative changes in plasma protein concentrations during tissue injury or inflammation (acute phase response) are often accompanied by specific alterations in the carbohydrate moieties of these proteins. The glycosylation changes comprise alterations in the type of branching of the carbohydrate structures as revealed by modulated reactivity of acute phase glycoproteins with the lectin concanavalin A. Interestingly, inflammation-induced changes in the glycosylation of acute phase proteins have been shown to affect the functional properties of these proteins. In this study we demonstrate that synthesis of acute phase protein α1-PI, the controlling inhibitor of neutrophil elastase, is significantly up-regulated in hepatic and lung-derived epithelial cells by the inflammatory mediator oncostatin M. Although oncostatin M markedly altered the concanavalin A reactivity of hepatic α1-PI, lung-derived epithelial cells did not change the pattern of α1-PI glycan branching upon stimulation with oncostatin M. These results indicate that inflammation-induced changes in glycosylation of α1-PI may have different impacts on functional properties of liver and lung-synthesized α1-PI.