ena-STUDY-MPIEB-18-08-2014-16:37:18:906-475
Murine lung microbiota
Commensal bacteria control the micro-ecology of metazoan epithelial surfaces with pivotal effect on tissue homeostasis and host defense. In contrast to the upper respiratory tract, the lower respiratory tract of healthy individuals is largely considered free of microorganisms. To understand airway micro-ecology we studied microbiota of sterilely excised lungs from mice of different origin including outbred wild mice caught in the natural environment or kept under non-specific-pathogen-free (SPF) conditions as well as inbred mice maintained in non-SPF, SPF or germ-free (GF) facilities. High-throughput pyrosequencing revealed that Betaproteobacteria and Ralstonia sp. represent the major constituents of murine lung microbiota. Non-cultivatable Betaproteobacteria were also identified by 16S rRNA gene cloning analysis in all but GF mice. Additionally, Pasteurellaceae, Enterobacteria and Firmicutes were isolated from the lungs of non-SPF, but not from SPF mouse lungs. Bacterial communities were detectable by FISH at alveolar epithelia without induction of inflammation. The overall composition across samples was similar at the phylum and family level, although significant differences with respect to the origin of the mice were observed at the community level. In addition, changing from a SPF to non-SPF environment was associated with increased species richness. Notably, higher bacterial colonization correlated with more and smaller sized alveolae in those mice. Our data indicate a common microbial composition in murine lungs, which is diversified through different environmental conditions and whose richness affects lung architecture. Identification of the microbiota of murine lungs will pave the path to study their influence on pulmonary immunity to infection and allergens using mouse models.
Commensal bacteria control the micro-ecology of metazoan epithelial surfaces with pivotal effect on tissue homeostasis and host defense. In contrast to the upper respiratory tract, the lower respiratory tract of healthy individuals is largely considered free of microorganisms. To understand airway micro-ecology we studied microbiota of sterilely excised lungs from mice of different origin including outbred wild mice caught in the natural environment or kept under non-specific-pathogen-free (SPF) conditions as well as inbred mice maintained in non-SPF, SPF or germ-free (GF) facilities. High-throughput pyrosequencing revealed that Betaproteobacteria and Ralstonia sp. represent the major constituents of murine lung microbiota. Non-cultivatable Betaproteobacteria were also identified by 16S rRNA gene cloning analysis in all but GF mice. Additionally, Pasteurellaceae, Enterobacteria and Firmicutes were isolated from the lungs of non-SPF, but not from SPF mouse lungs. Bacterial communities were detectable by FISH at alveolar epithelia without induction of inflammation. The overall composition across samples was similar at the phylum and family level, although significant differences with respect to the origin of the mice were observed at the community level. In addition, changing from a SPF to non-SPF environment was associated with increased species richness. Notably, higher bacterial colonization correlated with more and smaller sized alveolae in those mice. Our data indicate a common microbial composition in murine lungs, which is diversified through different environmental conditions and whose richness affects lung architecture. Identification of the microbiota of murine lungs will pave the path to study their influence on pulmonary immunity to infection and allergens using mouse models.