Aerosolized aqueous dust extracts collected near a drying lake trigger acute neutrophilic pulmonary inflammation reminiscent of microbial innate immune ligands

Trevor A Biddle; Keziyah Yisrael; Ryan Drover; Qi Li; Mia R Maltz; Talyssa M Topacio; Jasmine Yu; Diana Del Castillo; Daniel Gonzales; Hannah L Freund; Mark P Swenson; Malia L Shapiro; Jon K Botthoff; Emma Aronson; David R Cocker 3rd; David D Lo

doi:10.1016/j.scitotenv.2022.159882

Aerosolized aqueous dust extracts collected near a drying lake trigger acute neutrophilic pulmonary inflammation reminiscent of microbial innate immune ligands

Sci Total Environ. 2023 Feb 1;858(Pt 3):159882. doi: 10.1016/j.scitotenv.2022.159882. Epub 2022 Nov 2.

Authors

Affiliations

¹ Division of Biomedical Sciences, University of California, Riverside School of Medicine, Riverside, CA, USA; BREATHE Center, University of California, Riverside, Riverside, CA, USA; Center for Health Disparities Research, University of California, Riverside, Riverside, CA, USA.
² Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA, USA; College of Engineering-Center for Environmental Research and Technology (CE-CERT), University of California, Riverside, Riverside, CA, USA.
³ Division of Biomedical Sciences, University of California, Riverside School of Medicine, Riverside, CA, USA; BREATHE Center, University of California, Riverside, Riverside, CA, USA; Center for Conservation Biology, University of California, Riverside, Riverside, CA, USA.
⁴ Department of Microbiology, University of California, Riverside, Riverside, CA, USA.
⁵ School of Medicine, University of California, Riverside, Riverside, CA, USA.
⁶ Division of Biomedical Sciences, University of California, Riverside School of Medicine, Riverside, CA, USA; Center for Health Disparities Research, University of California, Riverside, Riverside, CA, USA.
⁷ Center for Conservation Biology, University of California, Riverside, Riverside, CA, USA.
⁸ Center for Health Disparities Research, University of California, Riverside, Riverside, CA, USA; Department of Microbiology, University of California, Riverside, Riverside, CA, USA.
⁹ Division of Biomedical Sciences, University of California, Riverside School of Medicine, Riverside, CA, USA; BREATHE Center, University of California, Riverside, Riverside, CA, USA; Center for Health Disparities Research, University of California, Riverside, Riverside, CA, USA. Electronic address: david.lo@medsch.ucr.edu.

PMID: 36334668
DOI: 10.1016/j.scitotenv.2022.159882

Abstract

Background: A high incidence of asthma is prevalent among residents near the Salton Sea, a large inland terminal lake in southern California. This arid region has high levels of ambient particulate matter (PM); yet while high PM levels are often associated with asthma in many environments, it is possible that the rapidly retreating lake, and exposed playa or lakebed, may contribute components with a specific role in promoting asthma symptoms.

Objectives: Our hypothesis is that asthma may be higher in residents closest to the Salton Sea due to chronic exposures to playa dust. Playa emissions may be concentrating dissolved material from the lake, with microbial components capable of inducing pulmonary innate immune responses. To test this hypothesis, we used a mouse model of aerosol exposures to assess the effects of playa dust.

Methods: From dust collected around the Salton Sea region, aqueous extracts were used to generate aerosols, which were injected into an environmental chamber for mouse exposure studies. We compared the effects of exposure to Salton Sea aerosols, as well as to known immunostimulatory reference materials. Acute 48-h and chronic 7-day exposures were compared, with lungs analyzed for inflammatory cell recruitment and gene expression.

Results: Dust from sites nearest to the Salton Sea triggered lung neutrophil inflammation that was stronger at 48-h but reduced at 7-days. This acute inflammatory profile and kinetics resembled the response to innate immune ligands LTA and LPS while distinct from the classic allergic response to Alternaria.

Conclusion: Lung inflammatory responses to Salton Sea dusts are similar to acute innate immune responses, raising the possibility that microbial components are entrained in the dust, promoting inflammation. This effect highlights the health risks at drying terminal lakes from inflammatory components in dust emissions from exposed lakebed.

Keywords: Airway infiltration; Alternaria; Salton Sea; Toll-like receptors.

MeSH terms

Animals
Dust*
Immunity, Innate
Mice
Pneumonia* / chemically induced

Substances

Dust