Characterization of two distinct transglutaminases of murine bone marrow-derived macrophages: effects of exposure of viable cells to cigarette smoke on enzyme activity

Abstract

The present study examines the effects of water soluble extracts of gas-phase cigarette smoke on intracellular transglutaminase activities of intact, murine, bone marrow-derived macrophages maintained in culture. Western blotting of cell lysates utilizing noncross-reactive antisera indicate that mouse bone marrow-derived macrophages contain both tissue-type transglutaminase and factor XIII-associated transglutaminase. This finding is also supported by data indicating that the intracellular transglutaminase activity of these cells contains thrombin-dependent and -independent components. Macrophages incubated with cigarette smoke solutions for 15 minutes at 37 degrees C display a dose-dependent decrease (maximum inhibition = 55%, p less than .001) in tissue-type (thrombin-independent) transglutaminase activity, as compared to control cells incubated with phosphate-buffered saline. Factor XIII (zymogen) is not inactivated following incubation of macrophages with smoke extracts. Smoke exposure under the conditions employed has no effect on either cell viability or adherence. Incubation with 2 microM retinoic acid for 24 hours leads to a modest (2-fold) induction of tissue transglutaminase, but does not induce factor XIII; in contrast, incubation with 10% homologous serum for 24 hours results in a decrease in factor XIII, but does not affect tissue transglutaminase. These data indicate that: bone marrow-derived macrophages contain factor XIII as well as tissue-type transglutaminase; and gas-phase cigarette smoke can inactivate tissue transglutaminase within viable murine bone marrow-derived macrophages, but cannot inactivate zymogenic factor XIII.