Single-cell RNA-seq Analysis Reveals That Prenatal Arsenic Exposure Results in Long-term, Adverse Effects on Immune Gene Expression in Response to Influenza A Infection.

Arsenic exposure via drinking water is a serious environmental health concern. Epidemiological studies suggest a strong association between prenatal arsenic exposure and subsequent childhood respiratory infections, as well as morbidity from respiratory diseases in adulthood, long after systemic clearance of arsenic. We investigated the impact of exclusive prenatal arsenic exposure on the inflammatory immune response and respiratory health after an adult influenza A virus (IAV) lung infection. C57BL/6J mice were exposed to 100 ppb sodium arsenite in utero, and subsequently infected with IAV (H1N1) after maturation to adulthood. Assessment of lung tissue and bronchoalveolar lavage fluid at various time points post-IAV infection reveals greater lung damage and inflammation in arsenic-exposed mice versus control mice. Single-cell RNA sequencing analysis of immune cells harvested from IAV-infected lungs suggests that the enhanced inflammatory response is mediated by dysregulation of innate immune function of monocyte-derived macrophages, neutrophils, natural killer cells, and alveolar macrophages. Our results suggest that prenatal arsenic exposure results in lasting effects on the adult host innate immune response to IAV infection, long after exposure to arsenic, leading to greater immunopathology. This study provides the first direct evidence that exclusive prenatal exposure to arsenic in drinking water causes predisposition to a hyperinflammatory response to IAV infection in adult mice, which is associated with significant lung damage.