Stachybotrys chartarum (atra) spore extract alters surfactant protein expression and surfactant function in isolated fetal rat lung epithelial cells, fibroblasts and human A549 cells

Le résumé fourni par la source

Moulds, notably Stachybotrys chartarum (atra), are constant contributors to air pollution particularly to air quality in buildings. The spores themselves or their volatile organic products are present in variable amounts in almost all environments, particularly in buildings affected by flooding. These moulds and products can account for the sick building syndrome and have been tied to such occurrences as the outbreak of pulmonary hemosiderosis and hemorrhage in infants in Cleveland, Ohio. The present study was designed to investigate the effects of S. chartarum extracts on surfactant protein expression, surfactant quality and cell survival in the developing lung. S. chartarum extracts were incubated with cultures of several cell types; isolated fetal lung type II cells and fetal lung fibroblasts, and human lung A549 cells, a continuously growing cell line derived from surfactant producing type II alveolar cells. MTT formazan assays were employed to test cell viability. The synthesis and release of the predominant surfactant protein A (SP-A), which is involved in the regulation of surfactant turnover and metabolism, and surfactant protein B (SP-B) involved in shuttling phospholipids between surfactant subcompartments was also assessed. Antibodies to these proteins and western blotting results were used to assess the quantity of protein produced by the various cell types. A novel approach utilizing captive bubble surfactometry was employed to investigate the quality of surfactant in terms of surface tension and bubble volume measurements. Electron microscopy was used to examine changes in cellular structure of control and S. chartarum-treated cells. Results of the study showed that exposure to the S. chartarum extracts had deleterious effects on fetal lung epithelial cell viability and their ability to produce pulmonary surfactant. S. chartarum extracts also induced deleterious changes to the developing fetal lung cells in terms of expression of SP-A and SP-B as well as to the surface tension reducing abilities of the pulmonary surfactant. Ultrastructurally, spore toxin associated changes were apparent in the isolated lung cells most notably in the lamellar bodies of fetal rat lung alveolar type II and human A549 cells. This study has demonstrated the potential damage to surfactant production and function which may be induced by inhaling S. chartarum toxins.

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