Automotive gasoline-induced epigenetic modifications and genotoxic effects in occupationally exposed workers

Area of Science:

• Environmental Health
• Molecular Toxicology
• Epigenetics

Background:

• Occupational exposure to automotive gasoline (containing benzene, toluene, xylene) is linked to genotoxic and epigenetic effects.
• The precise molecular mechanisms driving these alterations in exposed workers remain incompletely understood.

Purpose of the Study:

• To investigate global and gene-specific DNA methylation changes in gas station workers exposed to automotive gasoline.
• To explore the relationship between exposure biomarkers and DNA methylation alterations in repair genes.

Main Methods:

• Cross-sectional study of 217 participants in Rio de Janeiro, Brazil, categorized by exposure route (inhalation, dermal).
• Quantification of urinary biomarkers (t,t-MA, HA, MHA) for benzene, toluene, and xylene exposure.
• Analysis of global DNA methylation (LINE1, ALU) and promoter methylation of DNA repair genes (MGMT, MSH3, PARP1) via pyrosequencing.

Main Results:

• Increased DNA damage observed in workers exposed solely via inhalation.
• Decreased MGMT methylation in dual-route (inhalation/dermal) exposed workers; increased PARP1 methylation in inhalation-only exposed workers.
• Elevated MSH3 methylation in both exposed groups; lower ALU element methylation upon exposure; PARP1 methylation correlated with exposure biomarkers.

Conclusions:

• Gasoline exposure induces both direct genotoxic damage and epigenetic alterations, including changes in DNA repair gene methylation.
• MGMT methylation partially mediates the effect of exposure on DNA damage, suggesting a role in genomic instability.
• Observed DNA methylation patterns show promise as effect biomarkers for early detection and risk monitoring in occupationally exposed populations.