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 amou...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.展开更多
Smoking during pregnancy is a major source of fetal exposure to numerous harmful agents present in tobacco smoke. Lung development involves complex biochemical processes resulting in dramatic changes which continue ev...Smoking during pregnancy is a major source of fetal exposure to numerous harmful agents present in tobacco smoke. Lung development involves complex biochemical processes resulting in dramatic changes which continue even after birth. In addition to type I cells which form the blood-air barrier, type II alveolar epithelial (AE) cells have important and diverse functions related to immunological protection and stabilization of the alveolus through synthesis and secretion of the pulmonary surfactant. Apoptosis or programmed cells death is an important physiological process during lung embryogenesis and for the proper maintenance of homeostasis. Caspases are proteases that play important roles in regulating apoptosis. Caspase-3 is the key executioner caspase in the cascade of events leading to cell death by apoptosis. We explored the hypothesis that cigarette smoke extract (CSE) induces apoptosis in fetal rat lung type II AE cells by activation of caspase-3. To analyze these factors, isolated fetal rat lung type II AE cells were used. The cells were exposed to different concentrations of CSE (5%, 10% or 15%) (v/v) for 60 min. The results of the present study showed that CSE induced apoptosis in fetal rat lung type II AE cells with a significant increase (p 0.05) in caspase-3 activity and decrease in cell proliferation at CSE concentrations of 10% and 15% (v/v). These observations indicate that cigarette smoke extract induces apoptosis by activation of caspase-3 in fetal rat lung type II AE cells in a dose-dependent manner and may potentially alter the regulated development of the lung and the appearance of the surfactant-producing type II alveolar cells which are critical for the establishment of adequate gas exchange at birth.展开更多
文摘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.
文摘Smoking during pregnancy is a major source of fetal exposure to numerous harmful agents present in tobacco smoke. Lung development involves complex biochemical processes resulting in dramatic changes which continue even after birth. In addition to type I cells which form the blood-air barrier, type II alveolar epithelial (AE) cells have important and diverse functions related to immunological protection and stabilization of the alveolus through synthesis and secretion of the pulmonary surfactant. Apoptosis or programmed cells death is an important physiological process during lung embryogenesis and for the proper maintenance of homeostasis. Caspases are proteases that play important roles in regulating apoptosis. Caspase-3 is the key executioner caspase in the cascade of events leading to cell death by apoptosis. We explored the hypothesis that cigarette smoke extract (CSE) induces apoptosis in fetal rat lung type II AE cells by activation of caspase-3. To analyze these factors, isolated fetal rat lung type II AE cells were used. The cells were exposed to different concentrations of CSE (5%, 10% or 15%) (v/v) for 60 min. The results of the present study showed that CSE induced apoptosis in fetal rat lung type II AE cells with a significant increase (p 0.05) in caspase-3 activity and decrease in cell proliferation at CSE concentrations of 10% and 15% (v/v). These observations indicate that cigarette smoke extract induces apoptosis by activation of caspase-3 in fetal rat lung type II AE cells in a dose-dependent manner and may potentially alter the regulated development of the lung and the appearance of the surfactant-producing type II alveolar cells which are critical for the establishment of adequate gas exchange at birth.
