The potential immunotoxicity of emamectin benzoate on the human THP-1 macrophages

Deciphering the impact of greenhouse pesticides on hepatic metabolism profile: Toxicity experiments on HepG2 cells using chlorpyrifos and emamectin benzoate

Epidemiological evidence on the health effects of pesticide exposure among greenhouse workers is limited, and the mechanisms are lacking. Building upon our team's previous population study, we selected two pesticides, CPF and EB, with high detection rates, based on the theoretical foundation that the liver serves as a detoxifying organ, we constructed a toxicity model using HepG2 cells to investigate the impact of individual or combined pesticide exposure on the hepatic metabolism profile, attempting to identify targeted biomarkers. Our results showed that CPF and EB could significantly affect the survival rate of HepG2 cells and disrupt their metabolic profile. There were 117 metabolites interfered by CPF exposure, which mainly affected ABC transporter, biosynthesis of amino acids, center carbon metabolism in cancer, fatty acid biosynthesis and other pathways, 95 metabolites interfered by EB exposure, which mainly affected center carbon metabolism in cancer, HIF-1 signaling pathway, valine, leucine and isoleucine biosynthesis, fatty acid biosynthesis and other pathways. The cross analysis and further biological experiments confirmed that CPF and EB pesticide exposure may affect the HIF-1 signaling pathway and valine, leucine and isoleucine biosynthesis in HepG2 cells, providing reliable experimental evidence for the prevention and treatment of liver damage in greenhouse workers.

Spinetoram-Induced Potential Neurotoxicity through Autophagy Mediated by Mitochondrial Damage

Spinetoram is an important semi-synthetic insecticide extensively applied in agriculture. It is neurotoxic to insects, primarily by acting on acetylcholine receptors (nAChRs). However, few studies have examined the neurotoxicity of spinetoram in human beings. In this study, various concentrations (5, 10, 15, and 20 μM) of spinetoram were employed to expose SH-SY5Y cells in order to study the neurotoxic effects of spinetoram. The results showed that spinetoram exposure markedly inhibited cell viability and induced oxidative stress. It also induced mitochondrial membrane potential collapse (ΔΨm), and then caused a massive opening of the mitochondrial permeability transition pore (mPTP), a decrease in ATP synthesis, and Ca2+ overloading. Furthermore, spinetoram exposure induced cellular autophagy, as evidenced by the formation of autophagosomes, the conversion of LC3-I into LC3-II, down-regulation of p62, and up-regulation of beclin-1. In addition, we observed that p-mTOR expression decreased, while p-AMPK expression increased when exposed to spinetoram, indicating spinetoram triggered AMPK/mTOR-mediated autophagy. Complementarily, the effect of spinetoram on neurobehavior was studied using the zebrafish model. After being exposed to different concentrations (5, 10, and 20 μg/mL) of spinetoram, zebrafish showed neurobehavioral irregularities, such as reduced frequency of tail swings and spontaneous movements. Similarly, autophagy was also observed in zebrafish. In conclusion, spinetoram exposure produced potential neurotoxicity through autophagy mediated by mitochondrial damage. The experimental data and results of the neurotoxicity study of spinetoram provided above are intended to serve as reference for its safety assessment.

Studies on immunotoxicity induced by emamectin benzoate in zebrafish embryos based on metabolomics

Emamectin benzoate (EMB) is an insecticide for the control of agricultural lepidoptera pests, and also an anti-parasiticide for the control of exoparasites in aquaculture industry. Increased studies suggest that EMB could cause toxicity to non-targeted organisms, but its immunotoxicity to human remains unclear. In this study, zebrafish were used to investigate the immunotoxic effects induced by environmentally relevant doses of EMB. We observed that EMB exposure led to embryo mortality and delayed hatching, as well as increased malformations. Meanwhile, zebrafish exposed to EMB exhibited a significant decrease in the number of neutrophils and macrophages. In addition, untargeted metabolomics approach was developed to elucidate the mechanism of EMB-induced immunotoxicity. We found that a total of 10 shared biomarkers were identified in response to EMB exposure. Furthermore, pathway analysis identified glycerophospholipid metabolism was the most relevant pathway. Within this pathway, it was observed abnormal increases in glycerol 3-phosphate content, which could be attributed to the increased expression of GK5 and decreased expression of GPAT3. Our study provided novel and robust perspectives, which showed that EMB exposure to zebrafish embryos could cause metabolic disturbances that adversely affected development and immune system.

Examining the immunotoxicity of oil sands process affected waters using a human macrophage cell line

Oil sands process affected water (OSPW) is produced during the surface mining of the oil sands bitumen deposits in Northern Alberta. OSPW contains variable quantities of organic and inorganic components causing toxic effects on living organisms. Advanced Oxidation Processes (AOPs) are widely used to degrade toxic organic components from OSPW including naphthenic acids (NAs). However, there is no established biological procedure to assess the effectiveness of the remediation processes. Our previous study showed that human macrophage cells (THP-1) can be used as a bioindicator system to evaluate the effectiveness of OSPW treatments through examining the proinflammatory gene transcription levels. In the present study, we investigated the immunotoxicological changes in THP-1 cells following exposure to untreated and AOP-treated OSPW. Specifically, using proinflammatory cytokine protein secretion assays we showed that AOP treatment significantly abrogates the ability of OSPW to induce the secretion of IL-1β, IL-6, IL-8, TNF-α, IL-1Ra and MCP-1. By measuring transcriptional activity as well as surface protein expression levels, we also showed that two select immune cell surface markers, CD40 and CD54, were significantly elevated following OSPW exposure. However, AOP treatments abolished the immunostimulatory properties of OSPW to enhance the surface expression of these immune proteins. Finally, a transcriptome-based approach was used to examine the proinflammatory effects of OSPW as well as the abrogation of immunotoxicity following AOP treatments. Overall, this research shows how a human macrophage cell-based biomonitoring system serves as an effective in vitro tool to study the immunotoxicity of OSPW samples before and after targeted remediation strategies.

Potential adverse outcome pathway (AOP) of emamectin benzoate mediated cardiovascular toxicity in zebrafish larvae (Danio rerio)

Emamectin benzoate (EMB) is an efficient insecticide which widely used as an anthelmintic drug additive in aquaculture fish. However, its extensive use has resulted in widespread pollution in the aquatic environment. Previous studies have identified the potential developmental and neurotoxic effects of EMB, however, systematic studies pertaining to the cardiovascular toxic effects of EMB on fish are scarce. In this study, zebrafish embryos were exposed to EMB at concentrations of 0, 0.1, 0.25, 0.5, 1, 2, 4, and 8 mg/L for 3 days, aiming to investigate the cardiovascular toxic effects of EMB via examining morphology, cardiac function, and vascular development phenotypes. It revealed that EMB exposure led to marked deteriorated effects, including adverse effects on mortality, hatching rate, and general morphological traits, such as malformation, heart rate, body length, and eye area, in zebrafish embryos/larvae. Furthermore, EMB exposure resulted in abnormal cardiac function and vascular development, triggering neutrophil migration and aggregation toward the pericardial and dorsal vascular regions, and finalized apoptosis in the zebrafish heart region, these phenomena were further deciperred by the transcriptome analysis that the Toll-like receptor pathway, P53 pathway, and apoptotic pathway were significantly affected by EMB exposure. Moreover, the molecular docking and aspirin anti-inflammatory rescue assays indicated that TLR2 and TLR4 might be the potential targets of EMB. Taken together, our study provides preliminary evidence that EMB may induce apoptosis by affecting inflammatory signaling pathways and eventually lead to abnormal cardiovascular development in zebrafish. This study provides a simple toxicological AOP framework for safe pesticide use and management strategies.

Triphenyl phosphate-induced macrophages dysfunction by activation TLR4-mediated ERK/NF-κB pathway

Triphenyl phosphate (TPHP) is one of the most widely used organic phosphorus flame retardants and is ubiquitous in the environment. Studies have been reported that TPHP may lead to obesity, neurotoxicity and reproductive toxicity, but its impact on the immune system is almost blank. The present study was aimed to investigate the potential immunotoxicity of TPHP on macrophages and its underlying mechanism. The results demonstrated for the first time that TPHP (12.5, 25, and 50 μM)-induced F4/80⁺ CD11c⁺ phenotype of RAW 264.7 macrophages, accompanied by increased mRNA levels of inflammatory mediators, antigen-presenting genes (Cd80, Cd86, and H2-Aa), and significantly enhanced the phagocytosis of macrophage. Meanwhile, TPHP increased the expression of Toll-like receptor 4 (TLR4), and its co-receptor CD14, leading to significant activation of the downstream ERK/NF-κB pathway. However, co-exposure of cells to TAK-242, a TLR4 inhibitor, suppressed TPHP-induced F4/80⁺ CD11c⁺ phenotype, and down-regulated inflammatory mediators and antigen-presentation related genes, via blocked the TLR4/ERK/NF-κB pathway. Taken together, our results suggested that TPHP could induce macrophage dysfunction through activating TLR4-mediated ERK/NF-κB signaling pathway, and it may be the potential reason for health-threatening consequences.