Microbial communities respond to microenvironments in lungs of mice under simulated exposure to cadmium aerosols.

ABSTRACT

Inhalable pollutants are inducing factors of lung diseases and have been widely studied. Previous studies described imbalances in pulmonary microbial communities and representatively predominant microorganisms in clinical specimens of individuals with lung diseases. However, the direct effect of inhalable pollutants on pulmonary microorganisms has not been determined to date. Cadmium is a common inhalable pollutant from manufacturing activities, and its effect on pulmonary microorganisms was investigated in this study. Such techniques as optical respiratory plethysmography, high-throughput pulmonary histological assessment and differential centrifugation were used to characterize pulmonary microenvironments, and high-throughput sequencing was used to analyze pulmonary microbial diversity. We found variations in pulmonary microenvironmental factors, such as air supply level, nutrition and inflammatory stress. Under inhalable cadmium exposure at different doses, pulmonary microorganisms were differentially subjected and sensitive to various microenvironmental stresses (e.g., inflammation, pH, ventilation, nutrition and related changes of lung tissue structure) and might participate in microenvironmental remodeling, such as pneumonia and pulmonary fibrosis. Inflammatory stress and Lactobacillus were the main microenvironmental factor and susceptible microorganism, respectively. The various pulmonary microenvironments influenced the metabolisms of pulmonary microbial communities, presenting differences in microbial collinearities, gene function levels and metabolic pathway levels among groups.