B-esterase determination and organophosphate insecticide inhibitory effects in JEG-3 trophoblasts

Tris (2-chloroisopropyl) phosphate and Tris (nonylphenyl) phosphite Promote Human Renal Cell Apoptosis through the ERK/CEPBA/Long Non-Coding RNA Cytoskeleton Regulator Axis

Organophosphorus compounds (OPs) are widely used and have the potential to be harmful environmental toxicants to humans. Long non-coding RNA (lncRNA) plays a crucial regulatory role in cytotoxicity. This study aimed to investigate the effects of OPs on the expression of lncRNAs in cells. The effects of the industrial OPs TNPP and TCPP on both CYTOR and cellular viability were examined in the following human renal cell lines: HEK293T and HK-2. Both TCPP and TNPP downregulated CYTOR expression, increased reactive oxygen species levels, and induced apoptosis; the upregulated expression of CYTOR resulted in a reduction in apoptosis. The results of the luciferase reporter assay and the knock-down assay indicate that CEBPA binds to the upstream promoter region of CYTOR and regulates its transcription. Furthermore, TCPP and TNPP were found to downregulate the phosphorylation of ERK in the signaling pathway that is upstream of CEBPA. These results indicate that TCPP and TNPP can decrease the level of CEBPA by reducing ERK phosphorylation; this leads to a decrease in CYTOR expression, which further promotes cellular reactive oxygen species and apoptosis. Therefore, the ERK/CEBPA/CYTOR axis is one of the pathways by which organophosphates produce cytotoxicity, leading to renal cell injury. This study presents evidence for both the abnormal expression of lncRNA that is caused by organophosphates and the regulatory function of lncRNA regarding downstream cellular viability.

Can Organophosphates and Carbamates Cause Synergisms by Inhibiting Esterases Responsible for Biotransformation of Pyrethroids?

Hydrolysis catalyzed by general esterases (GEs) is the most efficient route for hydrolyzation of pyrethroid insecticides. Organophosphate (OP) and carbamate (CB) insecticides are known to inhibit GEs in addition to acetylcholinesterase (AChE), which is their main target. We hypothesize that synergies can be induced by OPs and CBs when mixed with pyrethroids, due to their inhibition of GE-dependent detoxification of pyrethroids. To test this hypothesis, we conducted mixture toxicity experiments with Daphnia magna using α-cypermethrin (α-cyp) in combination with the noninsecticidal OP tetraisopropyl pyrophosphoramide (iso-OMPA) and five AChE inhibitors diazinon, chlorpyrifos, chlorfenviphos, parathion, and aldicarb. In addition, the in vivo GE activity inhibition was measured for all compounds. Up to 10-fold synergy was found between α-cyp and iso-OMPA, and the degree of synergy correlated linearly with the inhibition of the GE activity. No synergy, however, was found in any of the insecticide mixtures nor was the GE activity inhibited within the nonlethal concentration range tested. It was concluded that the effect of the insecticides on AChE occurred at lower concentrations than their effect on GEs, making the daphnids become immobilized before any synergistic effects on mortality could be observed. The implications of the findings are discussed from a risk assessment perspective.

Effect of Chlorpyrifos on human extravillous-like trophoblast cells

An increased risk of pregnancy disorders has been reported in women and animal models exposed to organophosphate pesticides. However, less information is available on impacts to human placental function. Here, we addressed the impact of chlorpyrifos (CPF) on extravillous cytotrophoblasts (evCTB) employing HTR8/SVneo cells as an in vitro model. Cell proliferation, migration and invasion were not affected by CPF under conditions where cell viability was not compromised; however, we observed reduced expression of genes for vascular endothelial growth factor receptor 1, hypoxia-inducible factor 1-alpha, peroxisome proliferator activated receptor gamma, and the β-subunit of human chorionic gonadotropin. These results are the first effects reported by organophosphate pesticide in evCTB cells and show altered expression of several genes important for placental development that could serve as potential biomarkers for future research.