Wildfire Smoke Exposure Accelerates Age-Related Functional Decline in Caenorhabditis elegans

Abstract

Wildfire smoke (WFS) is an expanding source of fine particulate matter (PM2.5) with well-documented cardiopulmonary risks, yet its impact on organismal aging and functional decline remains incompletely understood. Here we use the nematode Caenorhabditis elegans to characterize the dose-dependent impacts of simulated WFS PM2.5 exposure (0.095–1000 µg/mL) on survival and age-associated functional outcomes. Locomotion and morphology were assessed at defined time points in adulthood, after which unexposed progeny of WFS-exposed nematodes were evaluated for identical tests to detect gross intergenerational effects. Parental (P0) worms subjected to a single 24 h WFS exposure exhibited dose-dependent reductions in lifespan at high concentrations and significant impairments in neuromuscular function at lower concentrations. A single P0 WFS exposure was also sufficient to induce deficits in multiple measures of locomotion and morphology, but these readouts were almost entirely resolved in F1 progeny. Additionally, RNA-sequencing on P0 nematodes was used to provide insight into biological processes underlying our in vivo observations, revealing WFS-associated aging-like transcriptomic signatures. Taken together, these results suggest that acute WFS exposure is sufficient to induce age-associated functional decline and establish C. elegans as a scalable, low-cost in vivo platform for quantifying WFS-driven toxicity.