有害な粉塵が肺のマイクロバイオームを書き換える(Dusty air is rewriting your lung microbiome)

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2025-10-21 カリフォルニア大学リバーサイド校(UCR)

カリフォルニア大学リバーサイド校の研究によると、乾燥が進むソルトン湖周辺の有毒粉じんを吸入すると、わずか1週間で肺内の微生物叢(マイクロバイオーム)が大きく変化することが判明した。健康なマウスに粉じんを吸入させる実験で、肺内の微生物構成や免疫応答が著しく変化し、特に炎症を引き起こすリポ多糖(LPS)を持つ細菌群が増加。免疫細胞の60%が好中球活性化マーカーを示し、強い炎症反応が確認された。粉じんは滅菌後でも影響を与え、死菌の化学的残留物が原因と考えられる。研究チームは、これが地域で喘息発症率が高い一因とみており、長期吸入による慢性呼吸疾患リスクを警告。今後は子どもへの影響や他の環境曝露(煙・排気・電子タバコ)との関連も検証する予定である。

<関連情報>

喘息マウスモデルにおける塵埃曝露に対する肺マイクロバイオームの多様な反応 Lung microbiomes’ variable responses to dust exposure in mouse models of asthma

Mia R. Maltz, Talyssa M. Topacio, David D. Lo, Marina Zaza, Linton Freund, Jon Botthoff, Mark Swenson,… , Emma Aronson
mSphere  Published:21 October 2025
DOI:https://doi.org/10.1128/msphere.00209-25

有害な粉塵が肺のマイクロバイオームを書き換える(Dusty air is rewriting your lung microbiome)

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, 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 are variable. The composition of lungs exposed to dust collected further from the Salton Sea was more similar to lungs from ambient air exposures; in contrast, dust collected near the Salton 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.

IMPORTANCE

Dust inhalation can lead to health effects, especially when toxic chemicals and microbes mix in with the dust particles. As California’s 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.

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