Lung microbiomes variable responses to dust exposure

Abstract

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, Californias 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. ImportanceDust inhalation can lead to health effects, especially when toxic chemicals and microbes mix in with the dust particles. As Californias Salton Sea dries up, it exposes lake bottom sediments to wind, which disperses the dried sediments. To mimic the effect of inhaling Salton Sea dust, we collected and filtered airborne dust to use in exposure experiments with mice in environmental chambers. We predicted that inhaling small dust particles, chemicals, and microbial residues found in this dust would affect mouse respiratory health, or change the microbes found inside their lungs. We found that inhaling dust led to lung inflammation and the dust source influenced the type of microbes found inside mouse lungs. As lakes continue to dry out, we expect greater health risks and changes to lung microbiomes. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=95 SRC="FIGDIR/small/648223v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@11e791eorg.highwire.dtl.DTLVardef@1a1a853org.highwire.dtl.DTLVardef@31ee4aorg.highwire.dtl.DTLVardef@135f40_HPS_FORMAT_FIGEXP M_FIG C_FIG