Effect of paraquat exposure on nitric oxide-responsive genes in rat mesencephalic cells

Transcriptomics of a cytoglobin knockout mouse: Insights from hepatic stellate cells and brain

The vertebrate respiratory protein cytoglobin (Cygb) is thought to exert multiple cellular functions. Here we studied the phenotypic effects of a Cygb knockout (KO) in mouse on the transcriptome level. RNA sequencing (RNA-Seq) was performed for the first time on sites of major endogenous Cygb expression, i.e. quiescent and activated hepatic stellate cells (HSCs) and two brain regions, hippocampus and hypothalamus. The data recapitulated the up-regulation of Cygb during HSC activation and its expression in the brain. Differential gene expression analyses suggested a role of Cygb in the response to inflammation in HSCs and its involvement in retinoid metabolism, retinoid X receptor (RXR) activation-induced xenobiotics metabolism, and RXR activation-induced lipid metabolism and signaling in activated cells. Unexpectedly, only minor effects of the Cygb KO were detected in the transcriptional profiles in hippocampus and hypothalamus, precluding any enrichment analyses. Furthermore, the transcriptome data pointed at a previously undescribed potential of the Cygb- knockout allele to produce cis-acting effects, necessitating future verification studies.

Mitochondrial and Proteasome Dysfunction Occurs in the Hearts of Mice Treated with Triazine Herbicide Prometryn

Prometryn is a methylthio-s-triazine herbicide used to control the growth of annual broadleaf and grass weeds in many cultivated plants. Significant traces of prometryn are documented in the environment, mainly in waters, soil, and plants used for human and domestic consumption. Previous studies have shown that triazine herbicides have carcinogenic potential in humans. However, there is limited information about the effects of prometryn on the cardiac system in the literature, or the mechanisms and signaling pathways underlying any potential cytotoxic effects are not known. It is important to understand the possible effects of exogenous compounds such as prometryn on the heart. To determine the mechanisms and signaling pathways affected by prometryn (185 mg/kg every 48 h for seven days), we performed proteomic profiling of male mice heart with quantitative liquid chromatography-tandem mass spectrometry (LC-MS/MS) using ten-plex tandem mass tag (TMT) labeling. The data suggest that several major pathways, including energy metabolism, protein degradation, fatty acid metabolism, calcium signaling, and antioxidant defense system were altered in the hearts of prometryn-treated mice. Proteasome and immunoproteasome activity assays and expression levels showed proteasome dysfunction in the hearts of prometryn-treated mice. The results suggest that prometryn induced changes in mitochondrial function and various signaling pathways within the heart, particularly affecting stress-related responses.

ADME/T-based strategies for paraquat detoxification: Transporters and enzymes

Paraquat (PQ) is a toxic, organic herbicide for which there is no specific antidote. Although banned in some countries, it is still used as an irreplaceable weed killer in others. The lack of understanding of the precise mechanism of its toxicity has hindered the development of treatments for PQ exposure. While toxicity is thought to be related to PQ-induced oxidative stress, antioxidants are limited in their ability to ameliorate the untoward biological responses to this agent. Summarized in this review are data on the absorption, distribution, metabolism, excretion, and toxicity (ADME/T) of PQ, focusing on the essential roles of individual transporters and enzymes in these processes. Based on these findings, strategies are proposed to design and test specific and effective antidotes for the clinical management of PQ poisoning.

Immediate and late systemic and lung effects of inhaled paraquat in rats

The immediate and the late effects of inhaled Paraquat (PQ) on systemic and lung inflammation and oxidative stress were investigated. Rats were exposed to saline (control group) and two doses of inhaled PQ (27 and 54 mg/m³) and studied variables were measured: 1) one day after the end of PQ exposure as "immediate condition", 2) 16 days after the end of PQ exposure as "late condition". Total and differential white blood cells (WBC) counts, lipid peroxidation and nitrite were increased but thiol, superoxide dismutase and catalase in the blood and BALF as well as methacholine EC50 was reduced in both conditions in the animals exposed to PQ compared to control groups (p < 0. 05 to p < 0.001). Most studied parameters in the immediate condition were significantly higher than the late condition (p < 0.05 to p < 0.001). Systemic and lung inflammation and oxidative stress due to inhaled PQ in both the immediate and the late conditions were shown. Although most measured parameters in the immediate condition were higher, all variables were significantly different with the control group even in late condition, indicating a long-term effect of inhaled PQ toxicity, which may help in a more effective treatment of PQ poising in the future.

Albicanol antagonizes Cd-induced apoptosis through a NO/iNOS-regulated mitochondrial pathway in chicken liver cells

Cadmium (Cd) induces hepatocyte injury by oxidative stress. Albicanol is a sesquiterpenoid extracted from the medicinal plant Dryopteris fragrans that has previously been shown to exhibit anti-aging and antioxidant activity. In this study, we explored the mechanism of albicanol inhibition of the Cd-induced apoptosis of chicken hepatoma cells (LMH) by treating these cells with CdCl2 (25 μM) and/or albicanol (2.5 × 10-5 μg mL-1) for 24 h. Under Cd treatment, the research results showed that the apoptosis rate markedly increased in LMH cells. In addition, the iNOS activity and NO content increased significantly, which promoted the expressions of genes associated with the mitochondrial apoptosis pathway (Bax, CytC, Caspase-3 and Caspase-9) and inhibited the expression of Bcl-2 in this pathway. However, Cd + albicanol co-treatment significantly reduced the apoptosis rate and the expressions of iNOS and genes associated with the mitochondrial apoptosis pathway (Bax, CytC, Caspase-3 and Caspase-9), and promoted the expression of Bcl-2 in this pathway. In addition, molecular docking supported a link between the albicanol ligand and the iNOS receptor. These results indicated that albicanol can inhibit Cd-induced apoptosis by regulating the NO/iNOS-mediated mitochondrial pathway.

Angiogenesis signaling in breast cancer models is induced by hexachlorobenzene and chlorpyrifos, pesticide ligands of the aryl hydrocarbon receptor

Breast cancer incidence is increasing globally and pesticides exposure may impact risk of developing this disease. Hexachlorobenzene (HCB) and chlorpyrifos (CPF) act as endocrine disruptors, inducing proliferation in breast cancer cells. Vascular endothelial growth factor-A (VEGF-A), cyclooxygenase-2 (COX-2) and nitric oxide (NO) are associated with angiogenesis. Our aim was to evaluate HCB and CPF action, both weak aryl hydrocarbon receptor (AhR) ligands, on angiogenesis in breast cancer models. We used: (1) in vivo xenograft model with MCF-7 cells, (2) in vitro breast cancer model with MCF-7, and (3) in vitro neovasculogenesis model with endothelial cells exposed to conditioned medium from MCF-7. Results show that HCB (3 mg/kg) and CPF (0.1 mg/kg) stimulated vascular density in the in vivo model. HCB and CPF low doses enhanced VEGF-A and COX-2 expression, accompanied by increased levels of nitric oxide synthases (NOS), and NO release in MCF-7. HCB and CPF high doses intensified VEGF-A and COX-2 levels but rendered different effects on NOS, however, both pesticides reduced NO production. Moreover, our data indicate that HCB and CPF-induced VEGF-A expression is mediated by estrogen receptor and NO, while the increase in COX-2 is through AhR and NO pathways in MCF-7. In conclusion, we demonstrate that HCB and CPF environmental concentrations stimulate angiogenic switch in vivo. Besides, pesticides induce VEGF-A and COX-2 expression, as well as NO production in MCF-7, promoting tubulogenesis in endothelial cells. These findings show that pesticide exposure could stimulate angiogenesis, a process that has been demonstrated to contribute to breast cancer progression.

Herbicide Paraquat provokes the stress responses of HPA axis of laboratory mouse, Mus musculus

Paraquat (PQ) is a herbicide and well characterized pneumotoxicant which is also known to induce neurodegeneration in organisms. Aim of this study was to investigate the effect of PQ on hypothalamic - pituitary - adrenal (HPA) axis. PQ was administered i.p.10 mg/kg body weight once a week for 5 weeks in laboratory male mice. Results indicate that SOD activity decreased while catalase activity and nitrate-nitrite level increased significantly in the hypothalamus of PQ treated mice. The expression of both AVP and CRH mRNA in the hypothalamus as well as ir-AVP and ir-CRH increased in the PVN of PQ treated mice compared to control. Immunoreactivity of nNOS and Hsp70 including NF-κB mRNA expression increased in the PVN of PQ treated mice. As expected, serum corticosterone level was also elevated significantly in the herbicide PQ treated mice. From these findings it is concluded that paraquat treatment is capable of activating the HPA axis via upregulating transcription and translation of the hypothalamic neuropeptides AVP and CRH as well as serum corticosterone level. Increase in both oxidative and nitrosative stress in PQ treated mice might be the driver which also contributed to the activation of HPA axis. It seems that stress induced reactive species (ROS, RNS) might be also responsible for the induced expression of NF-κB mRNA and Hsp70 protein which are considered as the reliable markers of certain types of stressors including PQ toxicity.

Retrospection on the Role of Soluble Guanylate Cyclase in Parkinson's Disease

Soluble guanylate cyclase (sGC) is an important transducing enzyme of cyclic guanosine monophosphate (cGMP) signaling pathway in striatum which has been considered as a potential target for the treatment of Parkinson's disease. Etiology of Parkinson's disease is multifactorial, finally resulting in abnormal proteinopathies causing degeneration of nigrostriatal pathways. Understanding the pathological basis of Parkinson's disease at molecular level is still an achievable target for the researchers and clinical practitioners. sGCs may be one of the causative factors resulting in Parkinson's disease due to glutamate toxicity or other event. This review presents the literature from articles of past five decades nearly as still this enzyme protein and its role in Parkinson's disease is not that clearly understood or presented till date. Recent interventions of this protein inhibition in the treatment of Parkinson's disease preclinically gave a chance to review the literature about this enzyme and its correlation with factors causing Parkinson's disease. We explored literature using PubMed and EMBASE for the role of sGC in Parkinson's disease. Databases were searched using the following terms: Parkinson's disease, neurotoxins, guanylate cyclase, sGC-cGMP pathway, and neurodegeneration. This review listed out the factors that have probability for stimulating sGC which already have been listed as a neurotoxins causing Parkinson's disease.

Effects of atrazine and chlorpyrifos on the production of nitric oxide and expression of inducible nitric oxide synthase in the brain of common carp (Cyprinus carpio L.)

The study aimed to investigate the effects of atrazine (ATR), chlorpyrifos (CPF), and the mixture of them on nitric oxide (NO) and inducible nitric oxide synthase (iNOS) in the brain of common carp. The triazine herbicide ATR and the organophosphorus insecticide CPF are frequently and extensively applied in agriculture all over the world. 220 Carps were averagely divided into eleven groups according to the different treatments and concentration, including the exposure and recovery experiments. In the present study, we investigated production of NO, iNOS activity and iNOS mRNA and protein expression in the brain of the common carp after a 40d exposure to ATR, CPF, alone or in combination, and a 40d recovery treatment. The results showed that the activity of iNOS and production of NO were significantly higher in all groups of fish exposed to high doses ATR, CPF and their mixture compared to control fish. After a 40d recovery treatment, iNOS activity and production of NO were lower than in the corresponding exposure groups in all the recovery groups. The mRNA and protein levels of iNOS were significantly higher in the high-dose group of ATR and CPF compared to control group, but were significantly lower in the group of the mixture of ATR and CPF compared to control group. Results indicated that NO and iNOS were involved in oxidative stress and brain tissue damage induced by ATR, CPF, and their mixture. Thus, the information presented in this study is helpful to understand the mechanism of ATR-, CPF- and ATR/CPF-mixture-induced neurotoxicity in fish.