Interaction Between Genetic Variants and Serum Levels of Organochlorine Pesticides Contributes to Parkinson’s Disease

Abstract

Background: There is evidence that genetic and environmental factors contribute to the onset and progression of Parkinson’s disease (PD). Pesticides are a class of environmental toxins that are linked to increased risk of PD. However, few studies have investigated the interaction between specific pesticides and genetic variants related to PD in the Chinese population.Methods: In this cross-sectional study, 19 serum levels of pesticides were measured. In addition, we also analyzed the interaction between specific pesticides and candidate genetic variants for PD. Finally, we investigated the mechanistic basis for the association between pesticides and increased risk of PD.Results: Serum levels of organochlorine pesticides including α-hexachlorocyclohexane (α-HCH), β-HCH, γ-HCH, δ-HCH, propanil, heptachlor, dieldrin, hexachlorobenzene, p,p’-dichlorodiphenyltrichloroethane (p,p’-DDE) and o,p’-dichloro-diphenyl-trichloroethane (o,p’-DDT) were higher in PD patients than in controls. α-HCH and propanil levels were associated with increased PD risk. Serum levels of dieldrin were associated with Hamilton Depression Scale and Montreal Cognitive Assessment scores in PD patients. The interaction between rs11931074 in α-synuclein (SNCA) and α-HCH or β-HCH, respectively, as well as rs16940758 in the microtubule-associated protein tau (MAPT) gene and δ-HCH were related to increased risk of PD. In addition, α-HCH and propanil enhanced the production of reactive oxygen species and decreased of mitochondrial membrane potential. Propanil but not α-HCH induced the aggregation of α-synuclein.Conclusions: Elevated serum levels of α-HCH and propanil are associated with increased risk of PD. Serum levels of dieldrin were associated with depression and cognitive function in PD patients. The interaction between genetic variants and pesticides also increased the risk of PD. Effects of genetic variants and pesticides on the risk of PD should be studied in more detail with a larger sample size to further understand the mechanisms involved.