CYP/PON genetic variations as determinant of organophosphate pesticides toxicity

Acephate Exposure Induces Transgenerational Ovarian Developmental Toxicity by Altering the Expression of Follicular Growth Markers in Female Rats

Acephate is an organophosphate foliar and soil insecticide that is used worldwide. In this study, the transgenerational ovarian developmental toxicity caused by acephate, along with its in utero reprogramming mechanisms, were explored. Thirty female virgin Wistar albino rats were randomly assigned to three groups: one control group and two acephate treatment groups. The treatment groups received daily low or high doses of acephate (34.2 mg/kg or 68.5 mg/kg body weight, respectively) from gestational day 6 until spontaneous labor, resulting in F1 offspring. At 28 days, a subgroup of F1 females were euthanized. The ovaries were extracted, thoroughly cleaned, and weighed before being fixed for further analysis. The remaining F1 females were mated with normal males to produce the F2 generation. The F1 female offspring presented reduced fertility and body weight, whereas the ovarian weight index and sex ratio increased in a dose-dependent manner. Structural analysis revealed altered follicular abnormalities with ovarian cells displaying pyknotic nuclei. Additionally, the gene and protein expression of Cyp19 decreased, whereas that of Gdf-9 increased in the high-dose treatment group (68.5 mg/kg). We also observed significantly increased expression levels of ovarian estrogen receptor 1 (Esr1) and insulin-like growth factor 1 (Igf1), whereas Insl3 expression was significantly decreased. The F2 female offspring presented reproductive phenotype alterations similar to those of F1 females including decreased fertility, reduced Cyp19 gene and protein expression, and structural ovarian abnormalities similar to those of polycystic ovary syndrome (PCOS). In conclusion, acephate induced ovarian developmental toxicity across two generations of rats, which may be linked to changes in the ovarian Cyp19, Gdf9, Insl3, and Igf1 levels.

Pon1 and Sult1a1 Polymorphisms and Breast Cancer Among Young Women in Brazil

Purpose: To investigate the association of genetic polymorphisms Gln192Arg and Leu55Met of Paraoxonase 1 (PON1) gene, and Arg213His of Sulfotransferase 1A1 (SUT1A1) gene with occurrence of breast cancer among young women living in Rio de Janeiro city. Methods: This is a hospital-based case-control study including 265 women aged 18-35 years, diagnosed with breast cancer at National Cancer Institute; and 277 controls in the same age group selected among women patients and companions of three general hospitals from Rio de Janeiro public health network. Polymorphisms genotyping was performed using the PCR-RFLP technique. Results: For PON1 gene, breast cancer women had a greater chance of being homozygote for Leu55Met polymorphism (ORadjusted = 1.42, 95% CI= 0.67-3.00, recessive model) and a lower chance of having at least one allele of Gln192Arg polymorphism (ORadjusted = 0.75, 95% CI = 0.50-1.13, dominant model), but without statistical significance. Accordingly, frequency of the haplotype Met55/Arg192 was lower among breast cancer women, but no statistically significant association was observed (ORadjusted = 0.85; 95% CI = 0.48-1.51). SULT1A1 His/His genotype was significantly associated with a protective effect for breast cancer (OR adjusted = 0.51, 95% CI = 0.28-0.91, recessive model). Conclusion: Arg213His polymorphism of SUT1A1 gene showed a protective effect against breast cancer among Brazilian young women. More studies with different designs are needed to understand the role of PON1 and SULT1A1 polymorphisms in breast cancer development in young Brazilian women.

The looming threat of profenofos organophosphate and microbes in action for their sustainable degradation

Organophosphates are the most extensively used class of pesticides to deal with increasing pest diversity and produce more on limited terrestrial areas to feed the ever-expanding global population. Profenofos, an organophosphate group of non-systematic insecticides and acaricides, is used to combat aphids, cotton bollworms, tobacco budworms, beet armyworms, spider mites, and lygus bugs. Profenofos was inducted into the system as a replacement for chlorpyrifos due to its lower toxicity and half-life. It has become a significant environmental concern due to its widespread presence. It accumulates in various environmental components, contaminating food, water, and air. As a neurotoxic poison, it inhibits acetylcholinesterase receptor activity, leading to dizziness, paralysis, and pest death. It also affects other eukaryotes, such as pollinators, birds, mammals, and invertebrates, affecting ecosystem functioning. Microbes directly expose themselves to profenofos and adapt to these toxic compounds over time. Microbes use these toxic compounds as carbon and energy sources and it is a sustainable and economical method to eliminate profenofos from the environment. This article explores the studies and developments in the bioremediation of profenofos, its impact on plants, pollinators, and humans, and the policies and laws related to pesticide regulation. The goal is to raise awareness about the global threat of profenofos and the role of policymakers in managing pesticide mismanagement.

Vitamin B12 alleviates malathion-induced toxicity in zebra fish by regulating cytochrome P450 and PgP expressions

The indiscriminate and rampant use of pesticides has raised serious concerns regarding their toxic impact on non-target organisms which underlines need for the development of an effective antidote. Metabolic activation of organophosphate pesticides by the phase I enzyme, cytochrome P450 plays a key role in influencing pesticide-toxicity. In this study, we have investigated the effect of environmentally relevant malathion concentration (100 μg/L) alone and in combination with vitamin B12 on the expression of genes related to xenobiotic metabolism such as CYP enzymes, PgP and the key oxidative stress responsive transcription factor, Nrf2 in zebra fish liver and brain. Expressions of Nrf2-trasncribed antioxidant genes and their activities were also measured. Administration of vitamin B12 successfully revived motor functions by modulation of AchE activity. Mechanistically, vitamin B12 was demonstrated to alleviate oxidative stress which was accompanied by decreased phase-I enzyme cyp3c1 and increased pgp expressions.

Selected herbicides screened for toxicity and analysed as inhibitors of both cholinesterases

Sets of 346 herbicides in use and 163 outdated no longer in use were collected from open access online sources and compared in silico with cholinesterases inhibitors (ChI) and drugs in terms of physicochemical profile and estimated toxic effects on human health. The screening revealed at least one potential adverse consequence for each herbicide class assigned according to their mode of action on weeds. The classes with most toxic warnings were K1, K3/N, F1 and E. The selection of 11 commercial herbicides for in vitro biological tests on human acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), the enzymes involved in neurotoxicity and detoxification of various xenobiotics, respectively, was based mainly on the structural similarity with inhibitors of cholinesterases. Organophosphate anilofos and oxyacetanilide flufenacet were the most potent inhibitors of AChE (25 μM) and BChE (6.4 μM), respectively. Glyphosate, oxadiazon, tembotrione and terbuthylazine were poor inhibitors with an estimated IC₅₀ above 100 μM, while for glyphosate the IC₅₀ was above 1 mM. Generally, all of the selected herbicides inhibited with a slight preference towards BChE. Cytotoxicity assays showed that anilofos, bensulide, butamifos, piperophos and oxadiazon were cytotoxic for hepatocytes (HepG2) and neuroblastoma cell line (SH-SY5Y). Time-independent cytotoxicity accompanied with induction of reactive oxygen species indicated rapid cell death in few hours. Our results based on in silico and in vitro analyses give insight into the potential toxic outcome of herbicides in use and can be applied in the design of new molecules with a less hazardous impact on humans and the environment.

Prenatal organophosphorus pesticide exposure and executive function in preschool-aged children in the Norwegian Mother, Father and Child Cohort Study (MoBa)

INTRODUCTION

Prenatal exposure to organophosphorus pesticides (OPPs) has been associated with neurodevelopmental deficits in children, however evidence linking OPPs with specific cognitive mechanisms, such as executive function (EF), is limited.

OBJECTIVE

This study aims to evaluate the association between prenatal exposure to OPPs with multiple measures of EF in preschool-aged children, while considering the role of variant alleles in OPP metabolism genes.

METHODS

We included 262 children with preschool attention-deficit/hyperactivity disorder (ADHD), and 78 typically developing children, from the Preschool ADHD substudy of the Norwegian, Mother, Father, and Child Cohort Study. Participants who gave birth between 2004 and 2008 were invited to participate in an on-site clinical assessment when the child was approximately 3.5 years; measurements of EF included parent and teacher rating on Behavior Rating Inventory of Executive Function-Preschool (BRIEF-P), and three performance-based assessments. We measured OPP metabolites in maternal urines collected at ∼17 weeks' gestation to calculate total dimethyl- (ΣDMP) and diethyl phosphate (ΣDEP) metabolite concentrations. We estimated multivariable adjusted β's and 95% confidence intervals (CIs) corresponding to a change in z-score per unit increase in log-ΣDMP/DEP. We further characterized gene-OPP interactions for maternal variants in PON1 (Q192R, M55L), CYP1A2 (1548T > C), CYP1A1 (IntG > A) and CYP2A6 (-47A > C).

RESULTS

Prenatal OPP metabolite concentrations were associated with worse parent and teacher ratings of emotional control, inhibition, and working memory. A one log-∑DMP increase was associated with poorer teacher ratings of EF on the BRIEF-P (e.g. emotional control domain: β = 0.55, 95% CI: 0.35, 0.74), when weighted to account for sampling procedures. We found less consistent associations with performance-based EF assessments. We found some evidence of modification for PON1 Q192R and CYP2A6 -47A > C. Association with other variants were inconsistent.

CONCLUSIONS

Biomarkers of prenatal OPP exposure were associated with more adverse teacher and parent ratings of EF in preschool-aged children.

Methyl benzoate derivatives: in vitro Paraoxonase 1 inhibition and in silico studies

Paraoxonase 1 (PON1) can metabolize some compounds such as aromatic carboxylic acid and unsaturated aliphatic esters, arylesters, cyclic carbonate, plucuronide drugs, some carbamate insecticide classes, nerve gases, and lactone compounds. Methyl benzoate has recently been shown to display potent toxicity against several insect species. In the current study, we aimed to investigate the effect of the methyl benzoate compounds (1-17) on PON1 activity. Methyl benzoate compounds inhibited PON1 with K_I values ranging from 25.10 ± 4.73 to 502.10 ± 64.72 μM. Compound 10 (methyl 4-amino-2-bromo benzoate) showed the best inhibition (K_I  = 25.10 ± 4.73 μM). Furthermore, using the ADME-Tox, Glide XP, and MM-GBSA tools of the Schrödinger Suite 2021-4, a complete ligand-receptor interaction prediction was performed to characterize the methyl benzoates (1-17), probable binding modalities versus the PON1.

Insights of OPs and PYR cytotoxic potential Invitro and genotoxic impact on PON1 genetic variant among exposed workers in Pakistan

Different pesticide chemicals are used to enhance crop yield by protecting from pests. Organophosphate (OPs) and Pyrethroid (PYR) are used in fields of Sanghar, Sindh Pakistan. PON1 an antioxidant enzyme implicated in OPs detoxification may predispose by OPs chronic exposure. This study was conducted to evaluate the toxic potential of active pesticide chemicals at cellular and genetic levels. To examine toxic potential, locally consumed pesticide n = 2 and reference pesticide compounds organophosphate (OPs): Chloropyrifos, Malathion and Pyrethroid (PYR): Cyprmethrin, Cyhalothrin n = 4 were tested against NIH 3T3 cells using MTS assay. Local consumer pesticides demonstrated relevance for half-maximum inhibitory concentration (IC50) 0.00035 mg/mL with selected compound. Malathion IC50 exhibited the highest cytotoxicity among four compounds at 0.0005 mg/mL. On genotoxicity analysis in exposed subjects n = 100 genotypes and alleles n = 200 exhibited significant differences in genotypic and allelic frequencies of pesticide exposed subjects and controls n = 150 (X2 = 22.9, p = 0.001). Screening of genotypes were performed by PCR- RFLP. Statistical assessment carried out using online software and tools. Results suggested that higher heterozygous genotype A/G (74%) may confer low PON1 metabolic activity towards pesticides in exposed subjects. Findings could be helpful to establish health plans by avoiding toxic chemicals that harming exposed population.

Organophosphate pesticides and new-onset diabetes mellitus: From molecular mechanisms to a possible therapeutic perspective

Organophosphate is a commonly used pesticide in the agricultural sector. The main action of organophosphate focuses on acetylcholinesterase inhibition, and it therefore contributes to acute cholinergic crisis, intermediate syndrome and delayed neurotoxicity. From sporadic case series to epidemiologic studies, organophosphate has been linked to hyperglycemia and the occurrence of new-onset diabetes mellitus. Organophosphate-mediated direct damage to pancreatic beta cells, insulin resistance related to systemic inflammation and excessive hepatic gluconeogenesis and polymorphisms of the enzyme governing organophosphate elimination are all possible contributors to the development of new-onset diabetes mellitus. To date, a preventive strategy for organophosphate-mediated new-onset diabetes mellitus is still lacking. However, lowering reactive oxygen species levels may be a practical method to reduce the risk of developing hyperglycemia.

Assessment of four organophosphorus pesticides as inhibitors of human acetylcholinesterase and butyrylcholinesterase

Toxicity of organophosphorus compounds (OPs) remains a major public health concern due to their widespread use as pesticides and the existence of nerve agents. Their common mechanism of action involves inhibition of enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) which are crucial for neurotransmission. Both chronic and acute poisoning by OPs can leave long-lasting health effects even when the patients are treated with standard medical therapy. Therefore, an increasing urgency exists to find more effective oxime reactivators for compounds which are resistant to reactivation, especially phosphoramidates. Here, we investigated in silico and in vitro interactions and kinetics of inhibition for human cholinesterases with four organophosphate pesticides-ethoprophos, fenamiphos, methamidophos and phosalone. Overall, ethoprophos and fenamiphos displayed higher potency as inhibitors for tested cholinesterases. Our results show that methamidophos-inhibited hAChE was more susceptible to reactivation than hAChE inhibited by fenamiphos by selected oximes. Molecular modelling enabled an evaluation of interactions important for specificity and selectivity of both inhibition and reactivation of cholinesterases. Two newly developed reactivators-bispyridinium triazole oxime 14A and zwitterionic oxime RS194B possess remarkable potential for further development of antidotes directed against pesticides and related phosphoramidate exposures, such as nerve agents tabun or Novichoks.

The ameliorative effect of curcumin on hepatic CYP1A1 and CYP1A2 genes dysregulation and hepatorenal damage induced by fenitrothion oral intoxication in male rats

This research aimed to assess curcumin (CUR) effects on fenitrothion (FNT), a broad-spectrum organophosphate insecticide, -induced hepatorenal damage. Thirty adult male Wistar rats were allocated at random to five equal groups orally administered distilled water containing 1% carboxyl methylcellulose, corn oil (1 mL/rat), CUR (100 mg/kg b.wt.), FNT (5 mg/kg b.wt.), or CUR + FNT. CUR and FNT were dosed three times a week for two months. At the end of this trial, blood and tissue samples (liver and kidney) were subjected to molecular, biochemical, and histopathological assessments. The results revealed that CUR significantly diminished the FNT-induced up-regulation of hepatic CYP1A1 and CYP1A2 transcriptional levels. Moreover, CUR significantly suppressed the increment of the serum levels of hepatic alanine aminotransferase, gamma-glutamyl transferase, and kidney damage indicators (urea and creatinine) in FNT-intoxicated rats. Furthermore, in the hepatic and renal tissues, CUR remarkably restored the FNT-associated depletion of the antioxidant enzymes (glutathione peroxidase, glutathione reductase, glutathione S transferase, catalase, and superoxide dismutase). In addition, CUR notably reduced the FNT-induced increment in malondialdehyde content in the hepatic and renal tissues. Besides, the pathological aberrations in liver and kidney tissues resulting from FNT exposure were significantly abolished in FNT + CUR treated rats. Overall, CUR could be an effective ameliorative agent against negative pesticide impacts like FNT.

Immunotoxic role of organophosphates: An unseen risk escalating SARS-CoV-2 pathogenicity

Consistent gathering of immunotoxic substances on earth is a serious global issue affecting people under pathogenic stress. Organophosphates are among such hazardous compounds that are ubiquitous in nature. They fuel oxidative stress to impair antiviral immune response in living entities. Aside, organophosphates promote cytokine burst and pyroptosis in broncho-alveolar chambers leading to severe respiratory ailments. At present, we witness COVID-19 outbreak caused by SARS-CoV-2. Infection triggers cytokine storm coupled with inflammatory manifestations and pulmonary disorders in patients. Since organophosphate-exposure promotes necroinflammation and respiratory troubles hence during current pandemic situation, additional exposure to such chemicals can exacerbate inflammatory outcome and pulmonary maladies in patients, or pre-exposure to organophosphates might turn-out to be a risk factor for compromised immunity. Fortunately, antioxidants alleviate organophosphate-induced immunosuppression and hence under co-exposure circumstances, dietary intake of antioxidants would be beneficial to boost immunity against SARS-CoV-2 infection.

Organophosphorus compounds and oximes: a critical review

Organophosphorus (OP) pesticides and nerve agents still pose a threat to the population. Treatment of OP poisoning is an ongoing challenge and burden for medical services. Standard drug treatment consists of atropine and an oxime as reactivator of OP-inhibited acetylcholinesterase and is virtually unchanged since more than six decades. Established oximes, i.e. pralidoxime, obidoxime, TMB-4, HI-6 and MMB-4, are of insufficient effectiveness in some poisonings and often cover only a limited spectrum of the different nerve agents and pesticides. Moreover, the value of oximes in human OP pesticide poisoning is still disputed. Long-lasting research efforts resulted in the preparation of countless experimental oximes, and more recently non-oxime reactivators, intended to replace or supplement the established and licensed oximes. The progress of this development is slow and none of the novel compounds appears to be suitable for transfer into advanced development or into clinical use. This situation calls for a critical analysis of the value of oximes as mainstay of treatment as well as the potential and limitations of established and novel reactivators. Requirements for a straightforward identification of superior reactivators and their development to licensed drugs need to be addressed as well as options for interim solutions as a chance to improve the therapy of OP poisoning in a foreseeable time frame.

Pesticide residue intake from fruits and vegetables and fecundability in a North American preconception cohort study

Intake of conventionally-grown fruits and vegetables with higher levels of pesticide residue contamination has been associated with poorer semen quality and lower probability of live birth among couples undergoing fertility treatment. We examined the association between dietary intake of pesticide residues and fecundability, the per cycle probability of conception, in a preconception cohort of pregnancy planners. We enrolled women aged 21-45 years who were attempting to conceive without use of fertility treatment into Pregnancy Study Online (PRESTO) from June 2013 through September 2019. Participants completed a baseline questionnaire on demographics, lifestyle factors, and medical and reproductive histories, and bimonthly follow-up questionnaires for up to 12 months or until reported conception. Ten days after baseline, participants completed the National Cancer Institute's Diet History Questionnaire II, a validated food frequency questionnaire. Using data from the USDA Pesticide Data Program, we classified fruits and vegetables as having high or low pesticide residues using a validated method. We examined the relation between greater intake of high- and low-pesticide residue fruits and vegetables with fecundability using proportional probabilities regression models, adjusted for potential confounders and accounting for consumption of organic produce. We restricted our analysis to 5234 women who had been attempting conception for ≤6 cycles at study entry, and further stratified by pregnancy attempt time at study entry (<3 vs. 3-6 cycles) to evaluate potential for reverse causation. Intakes of high- and low-pesticide residue fruits and vegetables were not appreciably related to fecundability in the full sample, or among women trying to conceive for <3 cycles at study entry. However, among women trying to conceive for 3-6 cycles at study entry, both high- and low-pesticide residue fruit and vegetable intakes were strongly inversely related to fecundability, indicating potential reverse causation bias. These results do not support the hypothesis that intake of pesticide residues from conventionally-grown fruits and vegetables is harmful to fertility, although non-differential exposure misclassification may have attenuated our findings.

Association between pesticide exposure and paraoxonase-1 (PON1) polymorphisms, and neurobehavioural outcomes in children: a systematic review

Environmental factors such as pollution, pesticide exposure and socio-demographic location have been implicated as a pressure capable of altering genetic make-up. Altered genetic sequence of genes encoding enzymes may result in single nucleotide polymorphism (SNP). Of peculiar interest is the genetic variance on the paraoxonase-1 gene induced by pre- and postnatal exposure to pesticides. SNP have been reported on the paraoxonase-1 gene and post-xenobiotic exposure and are presumed to alter gene sequence and ultimately enzymatic activity. The altered enzymatic activity may facilitate neurodevelopment disorders. Autism spectrum disorders (ASD) and attention deficit hyperactivity disorder (ADHD) are among the neurodevelopment disorders of which prevalence is concurrently associated with increasing environmental xenobiotic exposure. The variance on xenobiotic metabolising genes is associated with altered neurodevelopment outcome and ultimately altered neurobehavioural outcome. Prime interests of this systematic review were to establish an understanding of the sequences on the paraoxonase-1 gene associated with adverse neurobehavioural outcome. An in-depth literature search was conducted using the term combination "pesticide exposure, pre- and postnatal exposure, organophosphates/organophosphorus, single nucleotide polymorphism, paraoxonase-1 (PON-1), neurodevelopment/neurobehavioural outcome in child/infant". Articles published from the year 2000 to 2018 were considered for review. The result showed that variance on the PON1-108 and 192 alleles could be implicated in the development of altered neurobehavioural outcomes.

Investigations on hepatic and intestinal drug-metabolizing cytochrome P450 enzymes in wild boar compared to domestic swine

Drug-metabolizing cytochrome P450 (CYP) enzymes are especially important in wild animals as they are directly exposed to environmental pollutants and bioactive molecules of plants. Our main goal was to monitor the activity of certain CYP enzymes in wild boar compared to domestic swine, and to assess various modulatory factors of xenobiotic biotransformation in wild boar. Liver and intestinal mucosa (duodenum, jejunum, ileum, caecum) samples were collected from 49 hunted free-range wild boars and 15 wild boar fetuses; domestic pig samples (n = 40) were gained from a slaughter house. Specific activity of CYP1A2, CYP2C9, and CYP3A4 enzymes was assessed by luminometric assays. The activity of hepatic CYP1A2 and CYP3A4 enzymes was significantly higher in wild boars than in domestic pigs, while CYP2C9-mediated hepatic metabolism was significantly less intense in wild boars than in pigs. Certain modulatory factors (sex, sexual maturation, and season) were also confirmed in wild boars. The activity of all investigated intestinal CYP enzymes remained under detection level in each gut section in both species. Hepatic CYP2C9 and CYP3A4 enzymes were measurable in wild boar fetuses, but their activity was remarkably lower than in adults. The described interspecies differences might be explained with the altered exposure of wild and domesticated animals to specific CYP modulators. As CYP enzymes in wild boars can be highly influenced by environmental pollutants, following further studies, they may serve as ecotoxicological markers of agricultural or industrial toxicants. Investigating CYP-related drug metabolism in wildlife species can clarify some toxicokinetic interactions, thus having huge importance in the production of safe game meat.

Genetic polymorphisms as determinants of pesticide toxicity: Recent advances

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Genetic polymorphisms may influence pesticides-induced oxidative damage.Pesticides modulate immune-system cells functionality, leading to the onset of a dangerous pro-inflammatory microenvironment.

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DNA repair genes, Cytochrome P450 s, PON and GST genes have a key role in the metabolism of xenobiotics.

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Many workers are professionally exposed to pesticides with potential health consequences.

Occupational and environmental exposure to pesticides may induce harmful effects on human health by promoting the development of a wide range of disorders. Some of the most recently hypothesized mechanisms are oxidative stress and epigenetic modifications, however biological effects seem to be modulated mainly by the occurrence of genetic polymorphisms. The susceptibility to exposure can be evaluated by studying the most common polymorphisms of genes involved in the metabolism of organophosphorus compounds (cytochrome P450, glutathione transferase, acetyltransferases or paraoxonase 1). The aim of this article is to review recent literature data concerning the influence of genetic polymorphisms on pesticides-induced oxidative damage.

Mechanism underlying the effect of long-term exposure to low dose of pesticides on DNA integrity

Pesticides, including herbicides, insecticides and fungicides, are widely used in intensive agriculture. Recently, the long-term effects of pesticide exposure were found to be associated with many diseases. In this study, we evaluated the long-term effect of low-level exposure to a mixture of pesticides on DNA damage response (DDR) in relation to individual detoxifying variability. A residential population chronically exposed to pesticides was enrolled, biological/environmental pesticide levels; paroxonase 1 (PON-1) activity and 192 Q/R polymorphism and DDR were evaluated at three different periods of pesticide exposure. OGG1-dependent DNA repair activity was decreased in relation to pesticide exposure. The increase of DNA lesions and pesticide levels in the intensive pesticide-spraying period was independent on PON-1 activity. Next, human bronchial epithelial and neuronal cells were used as a model for in vitro evaluation of the mechanistic effect of pesticides. Pesticides induced mitochondrial dysfunction leading to ROS formation. ROS from mitochondria induced DNA damage, which in turn induced OGG1-dependent DNA repair activity through 8-oxoguanine DNA glycosylase 1 (OGG1) expression and activation. Even though OGG1 was overexpressed, an inhibition of its activity, associated with DNA lesion accumulation, was found at prolonged pesticide-exposure. A post-translational regulation of OGG1 by pesticide may be postulated. Taken together, long-term exposure to low-levels of pesticides affects DDR resulting in accumulation of DNA lesions that eventually may lead to cancer or neurological disorders.