Alveolar macrophages modulate the epithelial cell response to coal dust in vitro. Lee, Yu-Chen, and D. Eugene Rannels. Departments of Cellular & Molecular Physiology and Anesthesia, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
APStracts 2:0143L, 1995.
The response of the alveolar epithelium to coal dust exposure is poorly understood. Coal or other dusts may act on the epithelium directly, or indirectly through nearby alveolar macrophages (AM) which produce cytokines and other soluble products. AM and type II pneumocytes (T2P) were thus exposed to dust in coculture to evaluate their possible interactions. Anthracite coal dust PSOC 867 increased synthesis of extracellular matrix (ECM) components by T2P. AM alone did not produce ECM. Similarly, coculture of T2P with AM (3.75:1) had little effect on epithelial ECM synthesis. In contrast, coculture of T2P with AM significantly increased 867 effects on T2P rates of ECM synthesis, ECM fibronectin content and T2P levels of fibronectin mRNA. AM-conditioned medium did not change the 867 effect on T2P. Neither control nor 867-treated AM on Falcon culture inserts (0.45 [mu]m pore size) over T2P stimulated ECM synthesis by either untreated or dust-exposed epithelium. Thus AM-mediated changes in ECM synthesis by 867-treated T2P require close cell-cell interactions, suggesting a role for cell-cell contact or for short-lived soluble mediators of the AM effects. 

Received 11 May 1995; accepted in final form 10 August 1995.
APS Manuscript Number L143-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 24 August 1995.