Ethalfluralin impairs implantation by aggravation of mitochondrial viability and function during early pregnancy

Mechanisms of female reproductive toxicity in pigs induced by exposure to environmental pollutants

Environmental pollutants, including endocrine disruptors, heavy metals, nanomaterials, and pesticides, have been detected in various ecosystems and are of growing global concern. The potential for toxicity to non-target organisms has consistently been raised and is being studied using various animal models. In this review, we focus on pesticides frequently detected in the environment and investigate their potential exposure to livestock. Owing to the reproductive similarities between humans and pigs, various in vitro porcine models, such as porcine oocytes, trophectoderm cells, and luminal epithelial cells, are used to verify reproductive toxicity. These cell lines are being used to study the toxic mechanisms induced by various environmental toxicants, including organophosphate insecticides, pyrethroid insecticides, dinitroaniline herbicides, and diphenyl ether herbicides, which persist in the environment and threaten livestock health. Collectively, these results indicate that these pesticides can induce female reproductive toxicity in pigs and suggest the possibility of adverse effects on other livestock species. These results also indicate possible reproductive toxicity in humans, which requires further investigation.

Autophagy regulation and redox perturbation by transcrocetin suppress the growth of endometriosis

Until non-hormonal therapeutic targets for endometriosis are suggested, we focused on mitochondrial function and autophagy regulation in the disease. Transcrocetin is a carotenoid and retinoic acid with high antioxidant potency and antiproliferative effects in several diseases. In this study, we demonstrated the therapeutic mechanisms of transcrocetin in endometriosis using the End1/E6E7 and VK2/E6E7 cell lines. Transcrocetin suppressed the viability and proliferation of these cell lines and did not affect the proliferation of normal uterine stromal cells. p21 Waf1/Cip1 as a cell cycle regulator and target of p53, were increased by transcrocetin and caused the G1 arrest via inhibition of cyclin-dependent kinase activity, which might further cause cell death. Furthermore, we confirmed endoplasmic reticulum stress and calcium ion dysregulation in the cytosol and mitochondrial matrix, disrupting the mitochondrial membrane potential. Mitochondrial bioenergetics were suppressed by transcrocetin, and oxidative phosphorylation-related gene expression was downregulated. Moreover, the proliferation of End1/E6E7 and VK2/E6E7 cells was regulated by transcrocetin-induced oxidative stress. Finally, we verified the impairment of autophagic flux following pre-treatment with chloroquine. Therefore, transcrocetin may be a potent therapeutic alternative for endometriosis.

Norflurazon causes cell death and inhibits implantation-related genes in porcine trophectoderm and uterine luminal epithelial cells

Norflurazon, an inhibitor of carotenoid synthesis, is a pre-emergent herbicide that prevents growth of weeds. The norflurazon is known to hamper embryo development in non-mammals. However, specific toxic effects of norflurazon on mammalian maternal and fetal cells have not been elucidated. Thus, the hypothesis of this study is that norflurazon may influence the toxic effects between maternal and fetal cells during early pregnancy in pigs. We aimed to examine the toxic effects of norflurazon in porcine trophectoderm (Tr) and uterine luminal epithelium (LE) cells. Norflurazon, administered at 0, 20, 50 or 100 μM for 48 h was used to determine its effects on cell proliferation and cell-cycle arrest. For both uterine LE and Tr cell lines, norflurazone caused mitochondrial dysfunction by inhibiting mitochondrial respiration and ATP production, and down-regulated expression of mRNAs of mitochondrial complex genes. Norflurazon increased cell death by increasing intracellular calcium and regulating PI3K and MAPK cell signaling pathways, as well as endoplasmic reticulum (ER) stress, ER-mitochondrial contact, and autophagy-related target proteins. Norflurazone also inhibited expression of genes required for implantation of blastocysts, including SMAD2, SMAD4, and SPP1. These findings indicate that norflurazon may induce implantation failure in pigs and other mammals through adverse effects on both Tr and uterine LE cells.

Pyridaben induces apoptosis and inflammation in bovine mammary epithelial cells by disturbance of calcium homeostasis and upregulation of MAPK cascades

Pyridaben is a widely used pyridazinone insecticide used to protect crops against insects and mites. The toxicity of pyridaben has been reported in mice, zebrafish, the human reproductive system, nervous system, and respiratory system. Pyridaben can also be ingested by dairy cattle through feed. However, the toxicity of pyridaben in cattle has not been investigated on. Thus, this study focuses on demonstrating the toxicity of pyridaben in the bovine mammary glands and with the generation milk in the bovine mammary epithelial cells, as it is crucial to the continuance of the amount and the quality of the milk produced. We started by analyzing the intracellular toxicity along with the impact of pyridaben on the cell cycle distribution and the transcription of associated genes. Pyridaben treatment induced cell cycle arrest accompanied the disruption in G1 and S phases with imbalanced cytosolic and mitochondrial calcium ion homeostasis, and caused a destruction of mitochondrial membrane potential. This eventually led to apoptosis of MAC-T cells. We also investigated in the impact that pyridaben has on MAPK signaling proteins, where phosphorylation of ERK1/2, JNK, and p38 were upregulateed. Moreover, examination of the effect of pyridaben in the inflammatory genes revealed hyperactivation of the inflammatory gene transcription. This is the first research to assess the negative outcomes that pyridaben could impose on dairy cattle and milk production.

ATF5 Attenuates Low-magnesium-induced Apoptosis by Inhibiting Endoplasmic Reticulum Stress Via the Regulation of Mitochondrial Reactive Oxygen Species

Mitochondrial stress and endoplasmic reticulum stress (ERS) are known to be closely linked. ATF5 is a key regulator of mitochondrial stress and is involved in ERS regulation. Previously, we used a seizure model to demonstrate that ATF5 regulates mitochondrial stress. However, whether ATF5 affects ERS in epilepsy models has yet to be elucidated. In the present study, we investigated the effects of ATF5 on low-magnesium-induced ERS and the potential mechanisms that underlie these effects. We found that lentiviral overexpression of ATF5 significantly improved low-magnesium-induced ERS, as confirmed by the reduced expression levels of GRP78, PERK, ATF4, and CHOP. In addition, ATF5 overexpression reduced reactive oxygen species (ROS) production and elevated superoxide dismutase (SOD) activity, thus demonstrating that ATF5 plays a key role in maintaining redox homeostasis. Furthermore, ATF5 overexpression rescued low-magnesium-induced neuronal apoptosis, as evidenced by the reduced expression levels of Cleaved-caspase-3 and Bax, and the restored levels of Bcl2. However, these effects were significantly eliminated by lentiviral transduction with ATF5 interference. In addition, treatment of neurons with the mitochondrial antioxidant mitoquinone attenuated the onset of oxidative stress caused by ATF5 interference, partially restored the effect on ERS, and rescued cells from apoptosis. Collectively, these data show that ATF5 attenuates low-magnesium-induced neuronal apoptosis by inhibiting ERS through preventing the accumulation of mitochondrial ROS.

Fluchloralin induces developmental toxicity in heart, liver, and nervous system during early zebrafish embryogenesis

The zebrafish is a prominent vertebrate model popularly used for toxicity testing because of its rapid development and transparent embryos. Fluchloralin, a dinitroaniline herbicide used to control weeds, inhibits microtubule formation and cell division. The structurally homologous substances ethalfluralin and pendimethalin, which belong to the dinitroaniline family, were found to be genotoxic and to exert developmental toxicity via mitochondrial dysfunction in a zebrafish model. To date, developmental toxicity of fluchloralin in zebrafish has not been reported. In the present study, we identified morphological changes in developing zebrafish, including decreased survival rate and body length, and increased yolk sac edema. In dose-dependent response to fluchloralin exposure, inhibition of neurogenesis in the spinal cord and motor neuron defects were observed in transgenic zebrafish models (olig2:dsRed). Zebrafish exposed to fluchloralin also displayed organ dysfunction in the heart, liver, and pancreas in cmlc2:dsRed and lfabp:dsRed;elastase:GFP transgenic models. Fluchloralin increased cell death in the brain by promoting apoptosis, visualized via acridine orange staining, and by activating apoptosis signaling proteins, including cytochrome c1, zBax, and Bcl-XL. This study provides novel evidence supporting the necessity of controlling pollutants in aquatic environments.

Oryzalin impairs maternal-fetal interaction during early pregnancy via ROS-mediated P38 MAPK/AKT and OXPHOS downregulation

Oryzalin is a dinitroaniline pesticide for the control of weed growth via suppression of microtubule synthesis. There are studies about the deleterious effects of dinitroaniline pesticides on the reproductive system. Therefore, we attempted to demonstrate the toxic mechanisms of oryzalin on early pregnancy using porcine uterine epithelial cells (pLE) and trophectoderm (pTr) cells. According to our results, the viability and proliferation of pLE and pTr cells were suppressed in response to oryzalin exposure, and cell cycle progression was affected. Additionally, oryzalin induced apoptotic cell death and impaired mitochondrial membrane polarity in pLE and pTr cells. Moreover, we confirmed that oryzalin significantly downregulated adenosine triphosphate (ATP) production via the oxidative phosphorylation system and upregulated reactive oxygen species (ROS) generation in both pLE and pTr cells. The oryzalin-induced ROS generation was mitigated by N-acetylcysteine, a ROS scavenger, and further upregulation of phosphor-P38 MAPK/AKT/P70S6K protein expression was ameliorated in both pLE and pTr cells. We also confirmed that the suppression of migration and proliferation in oryzalin-treated pLE and pTr cells was restored upon oxidative stress mitigation. In summary, we revealed that the cytotoxic mechanisms of oryzalin-induced implantation failure were mediated by ROS-induced intracellular signaling regulation and migratory potential in pLE and pTr cells.

Folpet promotes apoptosis of bovine mammary epithelial cells via disruption of redox homeostasis and activation of MAPK cascades

Folpet, a phthalimide fungicide, is an agrochemical used to prevent fungal diseases in several crops. The toxicity of folpet has been demonstrated in Cyprinus carpio, pigs, and the human respiratory system. However, despite the possibilities of ingestion of folpet through feed, detrimental influences of folpet on dairy cattle have not been documented. Thus, this study aimed to record the harmful effects of folpet on the bovine mammary system and milk production using mammary epithelial cells (MAC-T cells), which play an essential role in the maintenance of yield and quality of milk production. In this study, we first confirmed that folpet exhibited cytotoxicity against MAC-T cells in both 2D and 3D cultures. Folpet treatment caused apoptosis, dysregulated intracellular calcium levels, and mitochondrial membrane potential, leading to cell death. We further demonstrated the induction of oxidative stress upon folpet treatment by assessing reactive oxygen species (ROS) content and lipid peroxidation in MAC-T cells. ROS generation following folpet treatment induced activation of MAPK cascades, including ERK1/2, JNK, and p38 signaling. This is the first report highlighting the detrimental impacts of folpet on bovine mammary glands and, consequently, the dairy industry by elucidating intracellular mechanisms using MAC-T cells.

Ethalfluralin induces developmental toxicity in zebrafish via oxidative stress and inflammation

Ethalfluralin, of dinitroaniline herbicide family, is an effective weed controller. Following residue detection in herbicide-treated fields, ethalfluralin was reported to interfere with early stages of implantation in some vertebrate species. However, the role of ethalfluralin in the development of zebrafish embryos has not been elucidated yet. Therefore, in the present study, we investigated the morphological and physiological changes that occur in the embryonic development of zebrafish due to ethalfluralin exposure. Results indicated that ethalfluralin decreased survival rate along with reduction in the hatching ratio and heartbeat. It was observed to cause edema in the heart and yolk sac, and apoptosis in the anterior region of the developing zebrafish larvae; as visualized through acridine orange and TUNEL staining. In addition, ethalfluralin increased the expression of the apoptosis-associated genes including tp53, cyc1, casp8, casp9, and casp3. The Seahorse Mito Stress analysis revealed that ethalfluralin slightly reduced mitochondrial respiration in live zebrafish embryos. Reactive oxygen species (ROS) production was also observed to be elevated in zebrafish larvae in response to ethalfluralin. Treatment with ethalfluralin decreased blood vessel formation in brain and intestine in flk1 transgenic zebrafish embryos. The decrease in angiogenesis related gene expression was specifically observed in vegfc, flt1, and kdrl, and in the intestinal vasculature related genes apoa4a, aqp3, fabp2, and vil1. Moreover, an increase in inflammatory genes such as cox2a, cox2b, cxcl-c1c, il8, mcl1a, mcl1b, and nf-κb was observed using real-time PCR analysis. Collectively, these results indicate that oxidative stress generated by exposure to ethalfluralin induced ROS generation, apoptosis, inflammation and anti-angiogenic effects, and therefore, ethalfluralin may be toxic to the development of zebrafish embryos.

Tebufenpyrad induces cell cycle arrest and disruption of calcium homeostasis in porcine trophectoderm and luminal epithelial cells

Tebufenpyrad is classified as a pyrazole acaricide and insecticide. It is widely used for several crops, especially in greenhouses, in several countries. While its unfavorable effects on non-target organisms have already been established, relatively little is known about its reproductive toxicity. Therefore, we demonstrated the biochemical effects of tebufenpyrad using porcine trophectoderm and porcine luminal epithelial cells, which are involved in implantation. We found that tebufenpyrad had antiproliferative effects and reduced cell viability. Tebufenpyrad also triggered apoptosis and excessive reactive oxygen species production. Furthermore, it induced cell cycle arrest in the G1 phase and disrupted calcium homeostasis in the cytosol and mitochondria. MAPK signaling pathways and the crosstalk among them were altered following tebufenpyrad treatment. In addition, the migration ability of cells was reduced after treatment with tebufenpyrad. Lastly, tebufenpyrad influenced the expression of genes related to pregnancy. Collectively, these results reveal the mechanism of the biochemical and physiological effects of tebufenpyrad to both trophectoderm and uterine cells and suggest that tebufenpyrad reduces the potential of successful implantation.