The role of oxidative stress in enantiomer-specific, bifenthrin-induced cytotoxicity in PC12 cells

Bifenthrin Caused Parkinson's-Like Symptoms Via Mitochondrial Autophagy and Ferroptosis Pathway Stereoselectively in Parkin-/- Mice and C57BL/6 Mice

It has been proposed that pyrethroid exposure contributes to the increasing prevalence of neurodegenerative diseases. However, the potential mechanisms remain unclear. The current study aimed to investigate the effects of the widely used pyrethroid bifenthrin on Parkinson's disease (PD) risk. Bifenthrin (1S-cis-bifenthrin, 1R-cis-bifenthrin, raceme) was administered to male Parkin-/- mice and C57BL/6 mice by oral gavage at a dose of 10 mg/kg bw/day for 28 days. Bifenthrin exposure significantly increased the time of pole climbing and decreased the period of rotarod running, indicating that bifenthrin decreased motor coordination in Parkin-/- mice, which was more evident by 1S-cis-bifenthrin. Furthermore, administration of bifenthrin induced obvious decreases in tyrosine hydroxylase (TH)+ cell count and the protein expression of TH. Increased protein of mitochondrial autophagy LC3B and p62 was observed after exposure to bifenthrin. Increased iron deposition and protein expression of iron transport transferrin (Tf) and transferrin receptor 2 (TfR2) was detected. 1S-cis-bifenthrin bound with Tf, TfR2, and GPX4 with lower binding energies than 1R-cis-bifenthrin, resulting in stronger interactions with these proteins. These results show structure-dependent PD-like effects of bifenthrin on motor activity and coordination associated with the disturbed mitochondrial autophagy and ferroptosis-related pathway. These data demonstrate that pyrethroid exposure increases the potential of Parkinson's-like symptoms via the ferroptosis pathway in Parkin-/- mice that is more pronounced than in C57BL/6 mice, providing a prospective enantioselective toxic effect of environmental neurotoxins on PD risk.

The role of stimulator of interferon genes-mediated AMPK/mTOR/P70S6K autophagy pathway in cyfluthrin-induced testicular injury

Cyfluthrin is widely used in the field of sanitary pest control by its wide insecticidal spectrum, high efficiency and low toxicity, low residue, and good biodegradability. But, as a double-edged sword, a large amount of cyfluthrin remains are still in the environment. The residual cyfluthrin is absorbed into the food chain through vegetation and then poses a risk to soil organisms and human health. Several studies have suggested that cyfluthrin is one of the main factors causing testicular damage, but the mechanism remains unclear. In this study, we established in vivo and in vitro models of testicular injury in rats and GC-2 cells exposed to cyfluthrin to explore whether stimulator of interferon genes (STING) gene mediates the regulation of AMPK/mTOR/p70S6K autophagy pathway, which lays a foundation for further study of the mechanism of testicular injury induced by cyfluthrin. The results showed that the activity of super oxide dismutase in testis decreased and the activity of malonic dialdehyde increased with the increase of concentration in vivo and in vitro. At the same time, the levels of mitochondrial damage and inflammation in the testis also increased, which further activated autophagy. In this process, the increased level of inflammation is related to the increased expression of STING gene, and AMPK/mTOR/p70S6K autophagy pathway is also involved. To sum up, cyfluthrin has certain reproductive toxicity, and long-term exposure can induce testicular cell damage. STING gene can participate in cyfluthrin-induced testicular injury through AMPK/mTOR/P70S6K autophagy pathway.

Enantioselectivity in the toxicological effects of chiral pesticides: A review

As a special category of pesticides, chiral pesticides have increased the difficulty in investigating pesticide toxicity. Based on their usage, chiral pesticides can be divided into insecticides, herbicides, and fungicides. Over the past decades, great efforts have been made on elucidating their toxicological effects. However, no literature has reviewed the enantioselective toxicity of chiral pesticides since 2014. In recent years, more chiral pesticides have been registered for application. As such, huge research progresses have been achieved in enantioselective toxicity of chiral pesticides. Generally, more researches have remedied the knowledge gap in toxicological effects of old and new chiral pesticides. And the toxicological endpoints being evaluated have become more specific rather than centering on basic toxicity and target organisms. Besides, the underlying mechanisms accounting for the enantioselectivity in toxicological effects of chiral pesticides have been discussed as well. All in all, this review provides the critical knowledge for risk assessments, and help to drive the green-technology of single- or enriched-enantiomer pesticides and formulation of relevant laws and regulations.

Transcriptomic and Histopathological Effects of Bifenthrin to the Brain of Juvenile Rainbow Trout (Oncorhynchus mykiss)

The increased global use of pyrethroids raises concern for non-target aquatic species. Bifenthrin, among the most predominantly detected pyrethroids in the environment, is frequently measured in water samples above concentrations reported to induce neuroendocrine and neurotoxic effects to several threatened and endangered fish species, such as the Chinook salmon and steelhead trout. To better characterize the neurotoxic effect of bifenthrin to salmonids, rainbow trout were treated with environmentally relevant concentrations of bifenthrin (15 and 30 ng/L) for two weeks and assessed for changes in transcriptomic profiles and histopathological alterations. The top bioinformatic pathways predicted to be impaired in bifenthrin-exposed trout were involved in gonadotropin releasing hormone signaling, the dysregulation of iron homeostasis, reduced extracellular matrix stability and adhesion, and cell death. Subsequent histopathological analysis showed a significant increase in TUNEL positive cells in the cerebellum and optic tectum of bifenthrin-treated trout, relative to controls (p < 0.05). These findings suggest that low, ng/L concentrations of bifenthrin are capable of dysregulating proper neuroendocrine function, impair the structural integrity of the extracellular matrix and cell signaling pathways in the brain, and induce apoptosis in neurons of juvenile salmonids following bifenthrin treatment, which is consistent with metabolomic profiles demonstrating a common target and mechanism.

Enantioselective cytotoxicity profile of o,p'-DDT in PC 12 cells

BACKGROUND

The continued uses of dichlordiphenyltrichloroethane (DDT) for indoor vector control in some developing countries have recently fueled intensive debates toward the global ban of this persistent legacy contaminant. Current approaches for ecological and health risk assessment has ignored the chiral nature of DDT. In this study by employing an array of cytotoxicity related endpoints, we investigated the enantioselective cytotoxicity of o,p'-DDT.

PRINCIPAL FINDINGS

we demonstrated for the first time that R-(-)-o,p'-DDT caused more neuron cell death by inducing more severe oxidative stress, which selectively imbalanced the transcription of stress-related genes (SOD1, SOD2, HSP70) and enzyme (superoxide dismutase and lactate dehydrogenase) activities, and greater cellular apoptosis compared to its enantiomer S-(+)-o,p'-DDT at the level comparable to malaria area exposure (parts per million). We further elucidated enantioselective modes of action using microarray combined with enzyme-linked immunosorbent assay. The enantioselective apoptosis might involve three signaling pathways via caspase 3, tumor protein 53 (p53) and NF(k)B.

CONCLUSIONS

Based on DDT stereochemistry and results reported for other chiral pesticides, our results pointed to the same directional enantioselectivity of chiral DDT toward mammalian cells. We proposed that risk assessment on DDT should consider the enantiomer ratio and enantioselectivities.

Cytotoxicity and DNA damage of five organophosphorus pesticides mediated by oxidative stress in PC12 cells and protection by vitamin E

Previous studies have demonstrated that pesticides could induce cytotoxicity and genotoxicity in vivo and in vitro, and that oxidative stress may be an important factor involved. However, investigations comparing the capability of different organophosphorous (OP) compounds to induce cytotoxicity, genotoxicity and oxidative stress are limited. Hence, the aim of this paper was to access the cytotoxic and genotoxic effects of five OPs or metabolites, Acephate (ACE), Methamidophos (MET), Chloramidophos (CHL), Malathion (MAT) and Malaoxon (MAO), and to clarify the role of oxidative stress, using PC12 cells. The results demonstrated that MET, MAT and MAO caused significant inhibition of cell viability and increased DNA damage in PC12 cells at 40 mg L(-1). MAO was more toxic than the other OPs. ACE, MET, MAT and MAO increased the levels of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA), and decreased the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) at 20 mg L(-1) and 40 mg L(-1) to different degrees. Pre-treatment with vitamin E(600 μM)caused a significant attenuation in the cytotoxic and genotoxic effect; pre-treatment reversed subsequent OP-induced elevation of peroxidation products and the decline of anti-oxidant enzyme activities. These results indicate that oxidative damage is likely to be an initiating event that contributes to the OP-induced cytotoxicity.