Effects of PM Exposure on the Methylation of Clock Genes in a Population of Subjects with Overweight or Obesity.

The expression of clock genes, regulating the synchronization of metabolic and behavioral processes with environmental light/dark cycles, is regulated by methylation and might be influenced by short-term exposure to airborne particulate matter (PM), especially in individuals that are hypersensitive to proinflammatory cues. The present study aimed to evaluate the effects of PM and PM on the methylation profile of the clock genes , , , , , , and in a population of 200 women with obesity. A significant association between PM exposure and the methylation of clock genes was found, namely, this was negative for gene and positive for the , , , and genes. PM was negatively associated with methylation of gene and positively with methylation of gene. Evidence was observed for effect modification from body mass index (BMI) regarding the gene: as PM increases, DNA methylation increases significantly for relatively low BMI values (BMI = 25), while it decreases in participants with severe obesity (BMI = 51). PM may therefore alter the epigenetic regulation of clock genes, possibly affecting circadian rhythms. Future studies are needed to clarify how alterations in clock gene methylation are predictive of disease development and how obesity can modulate the adverse health effects of PM.