Mice lung microbiomes' variable responses to dust exposure

Inhalation of dust is significant and relevant to health effects. As pollution and climate change worsen in dryland regions, wind currents entrain loose sediment and dust. This potentially disperses toxic geochemical and microbial burdens throughout the region. When inhaled environmental dust and host-associated microbiomes mingle, they pose exposure risks to host respiratory health. The Salton Sea, California’s largest lake, is shrinking thus exposing nearby communities to playa dust. Therefore, we analyze the effect of Salton Sea dust exposure in murine models to relate lung microbial communities and respiratory health. We used an environmental chamber to expose mice to dust filtrate or ambient air and examined the effects of those exposures on lung microbiomes. We found that lung microbial composition varied by dust exposure. Furthermore, dust elicited neutrophil recruitment and immune responses more than mice exposed to ambient air. Sources of dust differentially affected the composition of the lung core microbiome. Lung microbial diversity correlated with neutrophil recruitment as lungs associated with inflammatory responses harbored more diverse microbiomes. Although Salton Sea dust influences dust microbiomes and prevalent taxa, these responses were variable. The composition of lungs exposed to dust collected further from the Sea was more similar to lungs from ambient air exposures; in contrast, dust collected near the Sea yielded lung microbiomes that clustered further from lungs exposed to ambient air. As lakes continue to dry out, we expect greater public health risks in proximal dryland regions, which may correlate with dust microbial dispersal-related changes to lung microbiomes.