Unraveling the Toxicological Effects of HydroxyacetoneA Reaction Product in Electronic Cigarette Aerosols

Hydroxyacetone was previously detected at high concentrations
(up
to ∼12 mg/mL) in electronic cigarette (EC) aerosols, including
those derived from products associated with adverse health effects.
Given the limited understanding of its inhalation toxicology, we investigated
hydroxyacetone’s impact on human airway epithelial cells. Acute
exposures at the air–liquid interface (ALI) using 3D EpiAirway
tissuesa surrogate for human tracheobronchial epitheliumwere
analyzed via proteomics. Differential expression analysis identified
numerous affected proteins, with enrichment pointing to alterations
in mitochondrial function and actin cytoskeletal disruption as major
targets. Ingenuity Pathway Analysis (IPA) highlighted “Mitochondrial
Dysfunction” and “NRF2-Mediated Oxidative Stress”
among top toxicological categories, and “Nuclear Cytoskeletal
Signaling” as a key canonical pathway. To validate and extend
these findings, submerged cultures of BEAS-2B cells were exposed to
hydroxyacetone (0.01–10 mg/mL) and assessed for mitochondrial
activity, oxidative stress, and F-actin integrity. At 1 mg/mL, mitochondrial
membrane potential and reactive oxygen species (ROS) increased, with
elevated hydrogen peroxide detected in the culture medium. At 10 mg/mL,
mitochondrial activity declined significantly, accompanied by cell
rounding and apoptotic blebbing within 2 h. F-actin destabilization
occurred at 1, 3.33, and 10 mg/mL, with cytoplasmic and perinuclear
filaments more affected than cortical actin. Findings from ALI and
submerged models were concordant, supporting hydroxyacetone-induced
mitochondrial stress, oxidative damage, and cytoskeletal disruption.
These results suggest that hydroxyacetone concentrations found in
EC aerosols may contribute to respiratory toxicity and warrant further
investigation.