EXTRACELLULAR-MATRIX SYNTHESIS BY COAL DUST-EXPOSED TYPE-II EPITHELIAL-CELLS

Although integrity of the alveolar basement membrane may influence pro gression of lung injury induced by inhaled particulates, little is kno wn about direct effects of coal dusts on the alveolar epithelium or it s extracellular matrix (ECM). Effects of dust on synthesis of cell and ECM proteins by type II cells (T2P) was thus investigated. Three coal dusts (anthracite no. 867; bituminous no. 1451 and no. 1361) and mine dust MIT-3, of respirable size, were studied as a function of dose an d time over 3 days of primary T2P culture. On day 1, 750 mu g/ml of 86 7 were required to increase relative synthesis of ECM proteins (ECM/ce ll). MIT-3, 1451, and 1361 were without effect. By day 3, 867 or MIT-3 increased ECM/ cell 60-100% at 300 mu g/ml; 1451 produced modest, dos e-dependent stimulation, whereas 1361 remained without effect. None of the dusts caused significant cytotoxicity. The results show dose- and time-dependent effects of well-characterized coal and mine dusts to m odify partitioning of newly synthesized proteins into the ECM and sugg est that coal dust exposure may modulate structure or function of the subepithelial basement membrane.