Organometal-induced increases in oxygen reactive species: the potential of 2',7'-dichlorofluorescin diacetate as an index of neurotoxic damage

Animal Model of Autism Induced by Valproic Acid Combined with Maternal Deprivation: Sex-Specific Effects on Inflammation and Oxidative Stress

Autism spectrum disorder (ASD) etiology probably involves a complex interplay of both genetic and environmental risk factors, which includes pre- and perinatal exposure to environmental stressors. Thus, this study evaluated the effects of prenatal exposure to valproic acid (VPA) combined with maternal deprivation (MD) on behavior, oxidative stress parameters, and inflammatory state at a central and systemic level in male and female rats. Pregnant Wistar rats were exposed to VPA during gestation, and the offspring were submitted to MD. Offspring were tested for locomotor and social behavior; rats were euthanized, where the cerebellum, posterior cortex, prefrontal cortex, and peripheric blood were collected for oxidative stress and inflammatory analysis. It was observed that young rats (25-30 days old) exposed only to VPA presented a lower social approach when compared to the control group. VPA + MD rats did not present the same deficit. Female rats exposed to VPA + MD presented oxidative stress in all brain areas analyzed. Male rats in the VPA and VPA + MD groups presented oxidative stress only in the cerebellum. Regarding inflammatory parameters, male rats exposed only to MD exhibited an increase in pro-inflammatory cytokines in the blood and in the cortex total. The same was observed in females exposed only to VPA. Animals exposed to VPA + MD showed no alterations in the cytokines analyzed. In summary, gestational (VPA) and perinatal (MD) insults can affect molecular mechanisms such as oxidative stress and inflammation differently depending on the sex and brain area analyzed. Combined exposition to VPA and MD triggers oxidative stress especially in female brains without evoking an inflammatory response.

Environmentally persistent free radicals stimulate CYP2E1-mediated generation of reactive oxygen species at the expense of substrate metabolism

Environmentally persistent free radicals (EPFRs) are a recently recognized component of particulate matter that cause respiratory and cardiovascular toxicity. The mechanism of EPFR toxicity appears to be related to their ability to generate reactive oxygen species (ROS), causing oxidative damage. EPFRs were shown to affect cytochrome P450 (P450) function, inducing the expression of some forms through the Ah receptor. However, another characteristic of EPFRs is their ability to inhibit P450 activities. CYP2E1 is one of the P450s that is inhibited by EPFR (MCP230, the laboratory-generated EPFR made by heating silica 5% copper oxide, and silica [<0.2 μm in diameter] and 2-monochlorophenol at ≥230 °C) exposure. Because CYP2E1 is also known to generate ROS, it is important to understand the ability of EPFRs to influence the function of this enzyme and to identify the mechanisms involved. CYP2E1 was shown to be inhibited by EPFRs and to a lesser extent by non-EPFR particles. Because EPFR-mediated inhibition was more robust at subsaturating NADPH-P450 reductase (POR) concentrations, disruption of POR•CYP2E1 complex formation and electron transfer were examined. Surprisingly, neither complex formation nor electron transfer between POR and CYP2E1 was inhibited by EPFRs. Examination of ROS production showed that MCP230 generated a greater amount of ROS than the non-EPFR control particle (CuO-Si). When a POR/CYP2E1-containing reconstituted system was added to the pollutant-particle systems, there was a synergistic stimulation of ROS production. The results indicate that EPFRs cause inhibition of CYP2E1-mediated substrate metabolism, yet do not alter electron transfer and actually stimulate ROS generation. Taken together, the results are consistent with EPFRs affecting CYP2E1 function by inhibiting substrate metabolism and increasing the generation of ROS. SIGNIFICANCE STATEMENT: Environmentally persistent free radicals affect CYP2E1 function by inhibition of monooxygenase activity. This inhibition is not due to disruption of the POR•CYP2E1 complex or inhibition of electron transfer but due to the uncoupling of NADPH and oxygen consumption from substrate metabolism to the generation of reactive oxygen species. These results show that environmentally persistent free radicals block the metabolism of foreign compounds and synergistically stimulate the formation of reactive oxygen species that lead to oxidative damage within the organism.

The Fungicide Ipconazole Can Activate Mediators of Cellular Damage in Rat Brain Regions

This study aimed to investigate the toxicity of the fungicide ipconazole on oxidative status, cell death and inflammasome complex activation in the hypothalamus, cerebral cortex, striatum and hippocampus of rats. Female albino rats were randomly divided into a control group and four groups treated with ipconazole at doses of 1, 5, 10 and 20 mg/kg b.w., administered for six days. Ipconazole significantly increased MDA and ROS levels in all brain regions studied, while reducing catalase enzyme activity. The molecular expression of cell death-related genes (AKT1, APAF1, BNIP3, CASP3 and BAX) and the inflammasome complex (CASP1, IL1β, IL6, NLRP3, NFĸB and TNFα) was also assessed, showing increased expression in at least one brain region. The findings demonstrate that ipconazole induces central nervous system toxicity in mammals, highlighting its potential role as a risk factor in the development of neurodegenerative disorders in individuals exposed to this contaminant.

Methylphenidate Exposing During Neurodevelopment Alters Amino Acid Profile, Astrocyte Marker and Glutamatergic Excitotoxicity in the Rat Striatum

There is a public health concern about the use of methylphenidate (MPH) since the higher prescription for young individuals and non-clinical purposes is addressed to the limited understanding of its neurochemical and psychiatric consequences. This study aimed to evaluate the impact of early and chronic MPH treatment on the striatum focusing on amino acid profile, glutamatergic excitotoxicity, redox status, neuroinflammation and glial cell responses. Male Wistar rats were treated with MPH (2.0 mg/kg) or saline solution from the 15th to the 44th postnatal day. Biochemical and histological analyses were conducted after the last administration. MPH altered the amino acid profile in the striatum, increasing glutamate and ornithine levels, while decreasing the levels of serine, phenylalanine, and branched-chain amino acids (leucine, valine, and isoleucine). Glutamate uptake and Na+,K+-ATPase activity were decreased in the striatum of MPH-treated rats as well as increased ATP levels, as indicator of glutamatergic excitotoxicity. Moreover, MPH caused lipid peroxidation and nitrative stress, increased TNF alpha expression, and induced high levels of astrocytes, and led to a decrease in BDNF levels. In summary, our results suggest that chronic early-age treatment with MPH induces parallel activation of damage-associated pathways in the striatum and increases its vulnerability during the juvenile period. In addition, data presented here contribute to shedding light on the mechanisms underlying MPH-induced striatal damage and its potential implications for neurodevelopmental disorders.

The effect of exposure to radiofrequency LTE signal and coexposure to mitomycin-C in Chinese hamster lung fibroblast V79 cells

This study aims to investigate the cellular effects of radiofrequency exposure, 1950 MHz, long-term evolution (LTE) signal, administered alone and in combination with mitomycin-C (MMC), a well-known cytotoxic agent. Chinese hamster lung fibroblast (V79) cells were exposed/sham exposed in a waveguide-based system under strictly controlled conditions of both electromagnetic and environmental parameters, at specific absorption rate (SAR) of 0.3 and 1.25 W/kg. Chromosomal damage (micronuclei formation), oxidative stress (reactive oxygen species [ROS] formation), and cell cycle progression were analyzed after exposure and coexposure. No differences between exposed samples and sham-controls were detected following radiofrequency exposure alone, for all the experimental conditions tested and biological endpoints investigated. When radiofrequency exposure was followed by MMC treatment, 3 h pre-exposure did not modify MMC-induced micronuclei. Pre-exposure of 20 h at 0.3 W/kg did not modify the number of micronuclei induced by MMC, while 1.25 W/kg resulted in a significant reduction of MMC-induced damage. Absence of effects was also detected when CW was used, at both SAR levels. MMC-induced ROS formation resulted significantly decreased at both SAR levels investigated, while cell proliferation and cell cycle progression were not affected by coexposures. The results here reported provide no evidence of direct effects of 1950 MHz, LTE signal. Moreover, they further support our previous findings on the capability of radiofrequency pre-exposure to induce protection from a subsequent toxic treatment, and the key role of the modulated signals and the experimental conditions adopted in eliciting the effect.

Impact of Nintedanib and Anti-Angiogenic Agents on Uveal Melanoma Cell Behavior

Purpose

The purpose of this study was to investigate the direct impact of the combined angiokinase inhibitor nintedanib as well as the anti-angiogenic agents ranibizumab, bevacizumab, and aflibercept on the primary uveal melanoma (UM) cell line Mel270 and liver metastasis UM cell line OMM2.5.

Methods

The metabolic activity, viability, and oxidative stress levels were analyzed by the Thiazolyl Blue Tetrazolium Bromide (MTT), LIVE/DEAD, and reactive oxygen species (ROS) assays. Expression of intracellular VEGF-A165 and VEGF receptor-2 was detected by immunofluorescent staining. The secretion of VEGF-A165 into the cell culture supernatants was evaluated by VEGF-A165 ELISA.

Results

Nintedanib, at a concentration of 1 µg/mL, resulted in a median reduction of metabolic activity (for Mel270 of approximately 38% and for OMM2.5 of 46% compared to the untreated control) without exerting toxicity in either cell line, whereas the other 3 substances did not result in any changes (which also means that none of the 4 substances led to an increased cell death). Moreover, nintedanib (1 µg/mL) induced oxidative stress in the Mel270 by approximately 1.2 to 1.5-fold compared to the untreated control, but not the OMM2.5 cells.

Conclusions

Nintedanib could suppress the growth of UM cells in a concentration-dependent manner. The metastatic UM cell line OMM2.5 was not sensitive to the pro-oxidant activity of nintedanib. This study was the first to investigate nintedanib in the context of UM. We propose further investigation of this substance to elucidate its effects on this tumor entity with the hope of identifying advantageous therapeutic options for future adjuvant tumor therapies.

To promote healthy aging, focus on the environment

To build health equity for an aging world marked by dramatic disparities in healthy lifespan between countries, regions and population groups, research at the intersections of biology, toxicology and the social and behavioral sciences points the way: to promote healthy aging, focus on the environment. In this Perspective, we suggest that ideas and tools from the emerging field of geroscience offer opportunities to advance the environmental science of aging. Specifically, the capacity to measure the pace and progress of biological processes of aging within individuals from relatively young ages makes it possible to study how changing environments can change aging trajectories from early in life, in time to prevent or delay aging-related disease and disability and build aging health equity.

Neuromodulatory effect of 4-(methylthio)butyl isothiocyanate against 3-nitropropionic acid induced oxidative impairments in human dopaminergic SH-SY5Y cells via BDNF/CREB/TrkB pathway

Mitochondrial impairment, energetic crisis and elevated oxidative stress have been demonstrated to play a pivotal role in the pathological processes of Huntington's disease (HD). 3-Nitropropionic acid (3-NPA) is a natural neurotoxin that mimics the neurological dysfunctions, mitochondrial impairments and oxidative imbalance of HD. The current investigation was undertaken to demonstrate the neuroprotective effect of 4-(methylthio)butyl isothiocyanate (4-MTBITC) against the 3-NPA induced neurotoxicity in human dopaminergic SH-SY5Y cells. The experimental evidence of oxidative DNA damage by 3-NPA was elucidated by pBR322 DNA nicking assay. In contrast, the 4-MTBITC considerably attenuated the DNA damage, suggesting its free radical scavenging action against 3-NPA and Fenton's reagent. The dose and time-dependent increase of 3-NPA revealed its neurotoxic dose as 0.5 mM after 24 h of treatment of SH-SY5Y cells in MTT assay. In order to determine the optimal dose at which 4-MTBITC protects cell death, the 3-NPA (IC₅₀) induced cells were pretreated with different concentrations of 4-MTBITC for 1 h. The neuroprotective dose of 4-MTBITC against 3-NPA was found to be 0.25 μM. Additionally, the elevated GSH levels in cells treated with 4-MTBITC indicate its propensity to eliminate reactive species generated as a result of 3-NPA-induced mitochondrial dysfunction. Likewise, it was determined through microscopic and flow cytometric experiments that 3-NPA's induced overproduction of reactive species and a decline in mitochondrial membrane potential (MMP) could be efficiently prevented by pre-treating cells with 4-MTBITC. To elucidate the underlying molecular mechanism, the RT-qPCR analysis revealed that the pre-treatment of 4-MTBITC effectively protected neuronal cells against 3-NPA-induced cell death by preventing Caspase-3 activation, Brain-derived neurotrophic factor (BDNF) upregulation, activation of cAMP response element-binding protein (CREB) and Nrf2 induction. Together, our findings lend credence to the idea that pre-treatment with 4-MTBITC reduced 3-NPA-induced neurotoxicity by lowering redox impairment, apoptotic state, and mitochondrial dysfunction. The present work, in conclusion, presented the first proof that the phytoconstituent 4-MTBITC supports the antioxidant system, BDNF/TrkB/CREB signaling, and neuronal survival in dopaminergic SH-SY5Y cells against 3-NPA-induced oxidative deficits.

Genomic deciphering of sex determination and unique immune system of a potential model species rare minnow (Gobiocypris rarus)

Gobiocypris rarus is sensitive to environmental pollution, especially to heavy metal and grass carp reovirus (GCRV). Hence, it has potential utility as a biological monitor. Genetic deciphering of its unique immune system will advance our understanding of its unique adaptive strategies, which provide cues for its better application. A de novo genome of rare minnow was obtained, and its sex determination mechanism is ZZ/ZW. We identified several specific mutation genes and specific lost genes of rare minnow, and these might be related to the sensitivity of rare minnow to environmental stimuli. We also analyzed the gene expression level of different organs/tissues and found that several IFIT genes may play key roles in GCRV resistance. In addition, knockout of the gene PCDH10L indicates that PCDH10L affects Pb²⁺-induced mortality in rare minnow. Rare minnow is ready for genetic manipulation and shows potential as an emerging experimental model.

The Role of Human LRRK2 in Acute Methylmercury Toxicity in Caenorhabditis elegans

Methylmercury (MeHg) exposure and its harmful effects on the developing brain continue to be a global environmental health concern. Decline in mitochondrial function is central to the toxic effects of MeHg and pathogenesis of mitochondria-related diseases including Parkinson's disease (PD). LRRK2 (Leucine-rich repeat kinase 2) mutation is one of the most common genetic risk factors for PD. In this study, we utilize an acute toxicity model of MeHg exposure in the model organism Caenorhabditis elegans (C. elegans) to compare lifespan, developmental progression, mitochondrial membrane potential and reactive oxygen species (ROS) between the wild-type N2 strain, wild-type LRRK2 transgenic strain (WLZ1), and mutant LRRK2(G2019S) transgenic strain (WLZ3). Additionally, the expression levels of skn-1 and gst-4 were investigated. Our results show that acute MeHg exposure (5 and 10 µM) caused a significant developmental delay in the N2 and WLZ3 worms. Notably, the worms expressing wild-type LRRK2 were resistant to 5 µM MeHg- induced developmental retardation. ROS levels in response to MeHg exposure were increased in the N2 worms, but not in the WLZ1 or WLZ3 worms. The mitochondrial membrane potential was decreased in the N2 worms but increased in the WLZ1 and WLZ3 worms following MeHg exposure. Furthermore, MeHg exposure increased the expression of skn-1 in N2, but not in WLZ1 worms. Although skn-1 expression was increased in the WLZ3 worms following MeHg exposure, gst-4 expression was not induced. Both skn-1 and gst-4 had higher basal expression levels in LRRK2s transgenic than wild-type N2 worms. Knocking down of skn-1 with feeding RNAi had a significant developmental effect in WLZ1 worms; however, the effect was not found in WLZ3 worms. These results suggest that mitochondrial dysfunction and a defect in the SKN-1 signaling in the LRRK2 G2019S worms contribute to the severe developmental delay, establishing a modulatory role of LRRK2 mutation in MeHg-induced acute toxicity.

Ginkgo biloba L. Prevents Hypobaric Hypoxia-Induced Spatial Memory Deficit Through Small Conductance Calcium-Activated Potassium Channel Inhibition: The Role of ERK/CaMKII/CREB Signaling

Hypobaric hypoxia (HH) is a stressful condition, which is more common at high altitudes and can impair cognitive functions. Ginkgo biloba L. leaf extract (GBE) is widely used as herbal medicine against different disorders. Its ability to improve cognitive functions, reduce oxidative stress, and promote cell survival makes it a putative therapeutic candidate against HH. The present study has been designed to explore the effect of GBE on HH-induced neurodegeneration and memory impairment as well as possible signaling mechanisms involved. 220–250 gm (approximately 6- to 8-week-old) Sprague Dawley rats were randomly divided into different groups. GBE was orally administered to respective groups at a dose of 100 mg/kg/day throughout the HH exposure, i.e., 14 days. Memory testing was performed followed by hippocampus isolation for further processing of different molecular and morphological parameters related to cognition. The results indicated that GBE ameliorates HH-induced memory impairment and oxidative damage and reduces apoptosis. Moreover, GBE modulates the activity of the small conductance calcium-activated potassium channels, which further reduces glutamate excitotoxicity and apoptosis. The exploration of the downstream signaling pathway demonstrated that GBE administration prevents HH-induced small conductance calcium-activated potassium channel activation, and that initiates pro-survival machinery by activating extracellular signal–regulated kinase (ERK)/calmodulin-dependent protein kinase II (CaMKII) and the cAMP response element–binding protein (CREB) signaling pathway. In summary, the current study demonstrates the beneficial effect of GBE on conditions like HH and provides various therapeutic targets involved in the mechanism of action of GBE-mediated neuroprotection.

Paternal exposure to excessive methionine altered behavior and neurochemical activities in zebrafish offspring

An increase in plasma L-methionine (Met) levels, even if transitory, can cause important toxicological alterations in the affected individuals. Met is essential in the regulation of epigenetic mechanisms and its influence on the subsequent generation has been investigated. However, few studies have explored the influence of a temporary increase in Met levels in parents on their offspring. This study evaluated the behavioral and neurochemical effects of parental exposure to high Met concentration (3 mM) in zebrafish offspring. Adult zebrafish were exposed to Met for 7 days, maintained for additional 7 days in tanks that contained only water, and then used for breeding. The offspring obtained from these fish (F1) were tested in this study. During the early stages of offspring development, morphology, heart rate, survival, locomotion, and anxiety-like behavior were assessed. When these animals reached the adult stage, locomotion, anxiety, aggression, social interaction, memory, oxidative stress, and levels of amino acids and neurotransmitters were analyzed. F1 larvae Met group presented an increase in the distance and mean speed when compared to the control group. F1 adult Met group showed decreased anxiety-like behavior and locomotion. An increase in reactive oxygen species was also observed in the F1 adult Met group whereas lipid peroxidation and antioxidant enzymes did not change when compared to the control group. Dopamine, serotonin, glutamate, and glutathione levels were increased in the F1 adult Met group. Taken together, our data show that even a transient increase in Met in parents can cause behavioral and neurochemical changes in the offspring, promoting transgenerational effects.

Elucidating the role of hypoxia/reoxygenation in hippocampus-dependent memory impairment: do SK channels play role?

Professionals and mountaineers often face the problem of reperfusion injury due to re-oxygenation, upon their return to sea-level after sojourn at high altitude. Small conductance calcium-activated potassium channels (SK channels) have a role in regulating hippocampal synaptic plasticity. However, the role of SK channels under hypoxia-reoxygenation (H/R) is unknown. The present study hypothesized that SK channels play a significant role in H/R induced cognitive dysfunction. Sprague-Dawley rats were exposed to simulated HH (25,000 ft) continuously for 7 days followed by reoxygenation periods 3, 6, 24, 48, 72 and 120 h. It was observed that H/R exposure caused impairment in spatial memory as indicated by increased latency (p < 0.001) and pathlength (p < 0.001). The SK1 channel expression increased upon HH exposure (102.89 ± 7.055), which abrogated upon reoxygenation. HH exposure results in an increase in SK2 (CA3, 297.67 ± 6.69) and SK3 (CA1, 246 ± 5.13) channels which continued to increase gradually upon reoxygenation. The number of pyknotic cells (24 ± 2.03) (p < 0.01) and the expression of caspase-3 increased with HH exposure, which continued in the reoxygenation group (177.795 ± 1.264). Similar pattern was observed in lipid peroxidation (p < 0.001), LDH activity (p < 0.001) and ROS production (p < 0.001). A positive correlation of memory, cell death and oxidative stress indicates that H/R exposure increases oxidative stress coupled with SK channel expression, which may play a role in H/R-induced cognitive decline and neurodegeneration.

Treatment with isolated gold nanoparticles reverses brain damage caused by obesity

In this study, we performed two experiments. In the first experiment, the objective was to link gold nanoparticles (GNPs) with sodium diclofenac and/or soy lecithin and to determine their concentration in tissues and their toxicity using hepatic and renal analyzes in mice to evaluate their safety as therapeutic agents in the subsequent treatment of obesity. In the second experiment, we evaluated the effect of GNPs on inflammatory and biochemical parameters in obese mice. In the first experiment, we synthesized and characterized 18 nm GNPs that were administered intraperitoneally in isolation or in association with sodium diclofenac and/or soy lecithin in mice once daily for 1 or 14 days. Twenty-four hours after the single or final administration, the animals were euthanized, following which the tissues were removed for evaluating the concentration of GNPs, and serum samples were collected for hepatic and renal analysis. Hepatic damage was evaluated based on the levels of alanine aminotransferase (ALT), whereas renal damage was evaluated based on creatinine levels. A higher concentration of GNPs was detected in the tissues upon administration for 14 days, and there were no signs of hepatic or renal damage. In the second experiment, the mice were used as animal models of obesity and were fed a high-fat diet (obese group) and control diet (control group). After eight weeks of high-fat diet administration, the mice were treated with saline or with GNPs (average size of 18 nm) at a concentration of 70 mg/L (70 mg/kg) once a day, for 14 days, for 10 weeks. Body weight and food intake were measured frequently. After the experiment ended, the animals were euthanized, serum samples were collected for glucose and lipid profile analysis, the mesenteric fat content was weighed, and the brains were removed for inflammatory and biochemical analysis. In obese mice, although GNP administration did not reduce body and mesenteric fat weight, it reduced food intake. The glucose levels were reversed upon administration of GNPs, whereas the lipid profile was not altered in any of the groups. GNPs exerted a beneficial effect on inflammation and oxidative stress parameters, without reverting mitochondrial dysfunction. Our results indicate that the intraperitoneal administration of GNPs for 14 days results in a significant GNP concentration in adipose tissues, which could be an interesting finding for the treatment of inflammation associated with obesity. Based on the efficacy of GNPs in reducing dietary intake, inflammation, and oxidative stress, they can be considered potential alternative agents for the treatment of obesity.

The metabolic effect of α-ketoisocaproic acid: in vivo and in vitro studies

Maple syrup urine disease (MSUD) is characterized by a deficiency in the mitochondrial branched-chain α-keto acid dehydrogenase complex activity and, consequently, accumulation of the branched-chain amino acids and their respective branched-chain α-keto acids in fluids and the tissue. MSUD clinical symptoms include neurological alterations. KIC is considered one of the significant neurotoxic metabolites since its increased plasma concentrations are associated with neurological symptoms. We evaluated the effect of KIC intracerebroventricular (ICV) injection in hippocampal mitochondria function in rats. We also investigated the impact of KIC in cells' metabolic activity (using MTT assay) and reactive species (RS) production in HT-22 cells. For this, thirty-day-old male rats were bilaterally ICV injected with KIC or aCSF. Thus, 1 hour after the administration, animals were euthanized, and the hippocampus was harvested for measured the activities of mitochondrial respiratory chain enzymes and RS production. Furthermore, HT-22 cells were incubated with KIC (1-10 mM) in 6, 12, and 24 h. Mitochondrial complexes activities were reduced, and the formation of RS was increased in the hippocampus of rats after KIC administration. Moreover, KIC reduced the cells' metabolic ability to reduce MTT and increased RS production in hippocampal neurons. Impairment in hippocampal mitochondrial function seems to be involved in the neurotoxicity induced by KIC.

Fruticuline A, a chemically-defined diterpene, exerts antineoplastic effects in vitro and in vivo by multiple mechanisms

Natural products have been recognized as important bioactive compounds on the basis of their wide biological properties. Here we investigated the antitumor effect and molecular mechanisms of the diterpene Fruticuline A (fruti) from Salvia lachnostachys, in human cancer cell lineages and Solid Ehrlich Carcinoma in mice. Fruti reduced MCF-7 and HepG2 proliferation by the reduction of Cyclin D1 levels and decreased NF-κB gene levels in both cell types. Furthermore, fruti also induced apoptosis in HepG2 cells, reduced Bcl-2 gene expression and induced necroptosis by increasing Ripk in MCF-7 cells. In mice, fruti prevented tumor development and reduced Cyclin D1, Bcl-2 and Rela gene levels, and reduced the p-NF-κB/NF-κB ratio in tumor tissue. Furthermore, fruti induced necrosis and apoptosis, increased N-acetyl-β-D-glucosaminidase and TNF-α levels and reduced IL-10 and Vegf levels in tumor tissue. Collectively, fruti exerts antitumor effects through the inhibition of the NF-κB pathway, reducing Cyclin D1 and Bcl-2 levels. In vitro the apoptosis and necroptosis pathways are involved in the cellular death, whereas in vivo, cells undergo necrosis by increased tumor inflammation and reduction of angiogenesis. Thus, fruticuline A acts in tumor cells by multiple mechanisms and represents a promising molecule for drug development in cancer treatment.

Astaxanthin Suppresses PM2.5-Induced Neuroinflammation by Regulating Akt Phosphorylation in BV-2 Microglial Cells

Air pollution has become one of the most serious issues for human health and has been shown to be particularly concerning for neural and cognitive health. Recent studies suggest that fine particulate matter of less than 2.5 (PM2.5), common in air pollution, can reach the brain, potentially resulting in the development and acceleration of various neurological disorders including Alzheimer’s disease, Parkinson’s disease, and other forms of dementia, but the underlying pathological mechanisms are not clear. Astaxanthin is a red-colored phytonutrient carotenoid that has been known for anti-inflammatory and neuroprotective effects. In this study, we demonstrated that exposure to PM2.5 increases the neuroinflammation, the expression of proinflammatory M1, and disease-associated microglia (DAM) signature markers in microglial cells, and that treatment with astaxanthin can prevent the neurotoxic effects of this exposure through anti-inflammatory properties. Diesel particulate matter (Sigma-Aldrich) was used as a fine particulate matter 2.5 in the present study. Cultured rat glial cells and BV-2 microglial cells were treated with various concentrations of PM2.5, and then the expression of various inflammatory mediators and signaling pathways were measured using qRT-PCR and Western blot. Astaxanthin was then added and assayed as above to evaluate its effects on microglial changes, inflammation, and toxicity induced by PM2.5. PM2.5 increased the production of nitric oxide and reactive oxygen species and upregulated the transcription of various proinflammatory markers including Interleukin-1β (IL-1β), Interleukin-6 (IL-6), Tumor necrosis factor α (TNFα), inducible nitric oxide synthase (iNOS), triggering receptor expressed on myeloid cells 2 (TREM2), Toll-like receptor 2/4 (TLR2/4), and cyclooxygenase-2 (COX-2) in BV-2 microglial cells. However, the mRNA expression of IL-10 and arginase-1 decreased following PM2.5 treatment. PM2.5 treatment increased c-Jun N-terminal kinases (JNK) phosphorylation and decreased Akt phosphorylation. Astaxanthin attenuated these PM2.5-induced responses, reducing transcription of the proinflammatory markers iNOS and heme oxygenase-1 (HO-1), which prevented neuronal cell death. Our results indicate that PM2.5 exposure reformulates microglia via proinflammatory M1 and DAM phenotype, leading to neurotoxicity, and the fact that astaxanthin treatment can prevent neurotoxicity by inhibiting transition to the proinflammatory M1 and DAM phenotypes. These results demonstrate that PM2.5 exposure can induce brain damage through the change of proinflammatory M1 and DAM signatures in the microglial cells, as well as the fact that astaxanthin can have a potential beneficial effect on PM2.5 exposure of the brain.

Withdrawal Effects Following Methionine Exposure in Adult Zebrafish

Methionine (Met) has important functions for homeostasis of various species, including zebrafish. However, the increased levels of this amino acid in plasma, a condition known as hypermethioninemia, can lead to cell alterations. Met is crucial for the methylation process and its excesses interfere with the cell cycle, an effect that persists even after the removal of this amino acid. Some conditions may lead to a transient increase of this amino acid with unexplored persistent effects of Met exposure. In the present study, we investigated the behavioral and neurochemical effects after the withdrawal of Met exposure. Zebrafish were divided into two groups: control and Met-treated group (3 mM) for 7 days and after maintained for 8 days in tanks containing only water. In the eighth day post-exposure, we evaluated locomotion, anxiety, aggression, social interaction, and memory, as well as oxidative stress parameters, amino acid, and neurotransmitter levels in the zebrafish brain. Our results showed that 8 days after Met exposure, the treated group showed decreased locomotion and aggressive responses, as well as impaired aversive memory. The Met withdrawal did not change thiobarbituric acid reactive substances, reactive oxygen species, and nitrite levels; however, we observed a decrease in antioxidant enzymes superoxide dismutase, catalase, and total thiols. Epinephrine and cysteine levels were decreased after the Met withdrawal whereas carnitine and creatine levels were elevated. Our findings indicate that a transient increase in Met causes persistent neurotoxicity, observed by behavioral and cognitive changes after Met withdrawal and that the mechanisms underlying these effects are related to changes in antioxidant system, amino acid, and neurotransmitter levels.

Tanshinone IIA pretreatment promotes cell survival in human lung epithelial cells under hypoxia via AP-1-Nrf2 transcription factor

Activator protein-1 (AP-1) plays a decisive role in cell proliferation, apoptosis, and inflammation under hypoxia; thus, AP-1 subunits or dimers could be modulated for a desired phenomenon in a cell using a suitable compound of therapeutic potential. Herein, we used Tanshinone-IIA as an AP-1 (subunits) modulator, and the purpose of the study was to investigate the signaling mechanism exhibited by Tan-IIA in facilitating tolerance to hypoxia. A549 cells were pretreated with Tan-IIA and exposed to hypoxia for 6, 12, 24, and 48 h. Biochemical and molecular parameters were assessed in order to trace the signaling pathway. Tan-IIA attenuated hypoxia-induced oxidative stress by modulating the expression of AP-1 subunits (via. MAPK) and Nrf2 transcription factor, which in turn were responsible for maintaining the higher levels of antioxidant enzymes and genes (HO). Tan-IIA increased the cell survival. This could be attributed to an increased NO level via iNOS gene and activated JNK, ERK pathway that induced c-jun/c-fos, c-jun/fosB, junD/c-fos, and junD/fosB heterodimers. This in turn leads to the cell cycle progression by activating cyclins (D and B). This was further confirmed by the lower levels of p53 and their downstream genes (p16, p21, p27). In addition, Tan-IIA decreased pro-inflammatory cytokine levels by inhibiting the formation of junB/fra-1 heterodimer regulated by p38. Tan-IIA increased cell survival to hypoxia by maintaining the higher levels of cellular iNOS, HO-1, jun-D, c-jun, fos B via Nrf2-AP-1.

Thirty-day experimental diabetes impairs contractility and increases fatigue resistance in rat diaphragm muscle associated with increased anti-oxidative activity

Diabetes mellitus is a metabolic disorder that can generate tissue damage through several pathways. Alteration and dysfunction of skeletal muscle are reported including respiratory muscles, which may compromise respiratory parameters in diabetic patients. We have aimed to evaluate the diaphragm muscle contractility, tissue remodeling, oxidative stress, and inflammatory parameters from 30 day streptozotocin-treated rats. The diaphragm contractility was assessed using isolated muscle, tissue remodeling using histology and zymography techniques, and tissue oxidative stress and inflammatory parameters by enzyme activity assay. Our data revealed in the diabetes mellitus group an increase in maximum tetanic force (4.82 ± 0.13 versus 4.24 ± 0.18 N/cm² (p = 0.015)) and fatigue resistance (139.16 ± 10.78 versus 62.25 ± 4.45 s (p < 0.001)), reduction of 35.4% in muscle trophism (p < 0.001), increase of 32.6% of collagen deposition (p = 0.007), reduction of 21.3% in N-acetylglucosaminidase activity (p < 0.001), and increase of 246.7% of catalase activity (p = 0.002) without changes in reactive oxygen species (p = 0.518) and tissue lipid peroxidation (p = 0.664). All observed changes are attributed to the poor glycemic control (471.20 ± 16.91 versus 80.00 ± 3.42 mg/dL (p < 0.001)), which caused defective tissue regeneration and increased catalase activity as a compensatory mechanism.

Pulmonary oxidative stress in wild bats exposed to coal dust: A model to evaluate the impact of coal mining on health

This study aimed to verify possible alterations involving histological and oxidative stress parameters in the lungs of wild bats in the Carboniferous Basin of Santa Catarina (CBSC) state, Southern Brazil, as a means to evaluate the impact of coal dust on the health of wildlife. Specimens of frugivorous bat species Artibeus lituratus and Sturnira lilium were collected from an area free of coal dust contamination and from coal mining areas. Chemical composition, histological parameters, synthesis of oxidants and antioxidant enzymes, and oxidative damage in the lungs of bats were analyzed. Levels of Na, Cl, Cu, and Br were higher in both species collected in the CBSC than in the controls. Levels of K and Rb were higher in A. lituratus, and levels of Si, Ca, and Fe were higher in S. lilium collected in the carboniferous basin. Both bat species inhabiting the CBSC areas exhibited an increase in the degree of pulmonary emphysema compared to their counterparts collected from control areas. Sturnira lilium showed increased reactive oxygen species (ROS) and 2',7'-dichlorofluorescein (DCF) levels, while A. lituratus showed a significant decrease in nitrite levels in the CBSC samples. Superoxide dismutase (SOD) activity did not change significantly; however, the activity of catalase (CAT) and levels of glutathione (GSH) decreased in the A. lituratus group from CBSC compared to those in the controls. There were no differences in NAD(P)H quinone dehydrogenase 1 protein (NQO1) abundance or nitrotyrosine expression among the different groups of bats. Total thiol levels showed a significant reduction in A. lituratus from CBSC, while the amount of malondialdehyde (MDA) was higher in both A. lituratus and S. lilium groups from coal mining areas. Our results suggested that bats, especially A. lituratus, living in the CBSC could be used as sentinel species for harmful effects of coal dust on the lungs.

The Moss Leptodictyum riparium Counteracts Severe Cadmium Stress by Activation of Glutathione Transferase and Phytochelatin Synthase, but Slightly by Phytochelatins

In the present work, we investigated the response to Cd in Leptodictyum riparium, a cosmopolitan moss (Bryophyta) that can accumulate higher amounts of metals than other plants, even angiosperms, with absence or slight apparent damage. High-performance liquid chromatography followed by electrospray ionization tandem mass spectrometry of extracts from L. riparium gametophytes, exposed to 0, 36 and 360 µM Cd for 7 days, revealed the presence of γ-glutamylcysteine (γ-EC), reduced glutathione (GSH), and traces of phytochelatins. The increase in Cd concentrations progressively augmented reactive oxygen species levels, with activation of both antioxidant (catalase and superoxide dismutase) and detoxifying (glutathione-S-transferase) enzymes. After Cd treatment, cytosolic and vacuolar localization of thiol peptides was performed by means of the fluorescent dye monochlorobimane and subsequent observation with confocal laser scanning microscopy. The cytosolic fluorescence observed with the highest Cd concentrations was also consistent with the formation of γ-EC-bimane in the cytosol, possibly catalyzed by the peptidase activity of the L. riparium phytochelatin synthase. On the whole, activation of phytochelatin synthase and glutathione-S-transferase, but minimally phytochelatin synthesis, play a role to counteract Cd toxicity in L. riparium, in this manner minimizing the cellular damage caused by the metal. This study strengthens previous investigations on the L. riparium ability to efficiently hinder metal pollution, hinting at a potential use for biomonitoring and phytoremediation purposes.

Nose-Only Water-Pipe Smoke Exposure in Mice Elicits Renal Histopathological Alterations, Inflammation, Oxidative Stress, DNA Damage, and Apoptosis

The prevalence of water-pipe tobacco smoking is increasing worldwide, and is relatively high among youth and young adults. Exposure to water-pipe smoke (WPS) has been reported to affect various systems including the respiratory, cardiovascular and reproductive systems. However, the impact of WPS exposure on the kidney has received only scant attention. Here, we assessed the effect of nose-only WPS exposure for one or four consecutive weeks on renal histology, inflammation, oxidative stress, DNA damage, and apoptosis. The duration of the session was 30 min/day and 5 days/week. Control mice were exposed to air. Light and electron microcopy analysis revealed that the WPS exposure (especially at 4-week time point) caused degeneration of the endothelial cells of the glomerular capillaries and vacuolar degenerations of the proximal convoluted tubules. WPS exposure also significantly decreased the creatinine clearance, and significantly increased proteinuria and urinary kidney injury molecule-1 (KIM-1) concentration. Kidney lipid peroxidation, reactive oxygen species, and oxidized glutathione were significantly increased. WPS exposure also affected the concentration of reduced glutathione and the activity of catalase. Likewise, renal concentrations of interleukin (IL)-6, IL-1β and KIM-1 were augmented by WPS exposure. Moreover, WPS caused DNA damage as evaluated by comet assay, and increased the expression of cleaved caspase-3 and cytochrome C in the kidney. We conclude that exposure of mice to WPS caused renal histopathological alterations, inflammation, oxidative stress, DNA damage, and apoptosis. If the latter findings could be substantiated by controlled human studies, it would be an additional cause for disquiet about an established public health concern.

Trans-Himalayan Phytococktail Confers Protection Against Hypobaric Hypoxia-Induced Hippocampal Neurodegeneration and Memory Impairment in Male Sprague Dawley Rats

Background: Exposure to hypobaric hypoxia (HH) has been reported to cause neurodegeneration and memory impairment. Hippophae rhamnoides, Prunus armeniaca, and Rhodiola imbricata, the indigenous plants of Indian Trans-Himalaya are widely used in traditional Tibetan and Amchi system of medicine. These are rich sources of diverse bioactive metabolites having prophylactic and therapeutic uses against a wide array of neurodegenerative diseases. The objective of this study was to elucidate the prophylactic and neuroprotective efficacy of formulated phytococktail (PC) against simulated HH-induced neurodegeneration in male Sprague Dawley (SD) rats. Materials and Methods: A PC containing H. rhamnoides fruit pulp, P. armeniaca fruit pulp, and R. imbricata dry root extract (100:50:1) was formulated. The neuroprotective efficacy of PC was evaluated in male SD rats following exposure to 7 day HH at simulated altitude (25,000 ft, 282 mm Hg). Rats were divided into four groups viz., normoxia group (NOR), normoxic group treated with PC (NORPC), 7 day hypoxic group treated with vehicle (7DH), and 7 day hypoxic group treated with PC (7DHPC). Memory impairment and neuromorphological alterations were measured. Targeted protein expression was analyzed by immunoblotting study. Results: PC supplementation significantly reduced the oxidative stress markers during exposure to HH. Spatial memory impairment by HH was significantly ameliorated by PC. HH-induced augmented pyknosis, decreased dendritic arborization, and increased Hoechst-positive neurons in hippocampal CA3 region were significantly ameliorated by PC. Immunoblotting study showed upregulation of BDNF and TrkB expression by PC. PC also prevented the hippocampal neurodegeneration by activating the PI3K/AKT signaling pathway, which leads to GSK-3β inactivation by its phosphorylation and alleviation of hippocampal Caspase3 expression leading to inhibition of apoptotic neuronal cell death. Conclusion: The present study advocates the potential role of PC as an effective neuroprotective supplement in preventing HH-induced neurodegeneration. Activation of the PI3K/Akt pathway through BDNF/TrkB interaction following PC supplementation after exposure to HH inhibits hippocampal neuronal apoptosis and memory impairment.

Cross-talk between guanidinoacetate neurotoxicity, memory and possible neuroprotective role of creatine

Guanidinoacetate Methyltransferase deficiency is an inborn error of metabolism that results in decreased creatine and increased guanidinoacetate (GAA) levels. Patients present neurological symptoms whose mechanisms are unclear. We investigated the effects of an intrastriatal administration of 10 μM of GAA (0.02 nmol/striatum) on energy metabolism, redox state, inflammation, glutamate homeostasis, and activities/immunocontents of acetylcholinesterase and Na⁺,K⁺-ATPase, as well as on memory acquisition. The neuroprotective role of creatine was also investigated. Male Wistar rats were pretreated with creatine (50 mg/kg) or saline for 7 days underwenting stereotactic surgery. Forty-eight hours after surgery, the animals (then sixty-days-old) were divided into groups: Control, GAA, GAA + Creatine, and Creatine. Experiments were performed 30 min after intrastriatal infusion. GAA decreased SDH, complexes II and IV activities, and ATP levels, but had no effect on mitochondrial mass/membrane potential. Creatine totally prevented SDH and complex II, and partially prevented COX and ATP alterations. GAA increased dichlorofluorescein levels and decreased superoxide dismutase and catalase activities. Creatine only prevented catalase and dichlorofluorescein alterations. GAA increased cytokines, nitrites levels and acetylcholinesterase activity, but not its immunocontent. Creatine prevented such effects, except nitrite levels. GAA decreased glutamate uptake, but had no effect on the immunocontent of its transporters. GAA decreased Na⁺,K⁺-ATPase activity and increased the immunocontent of its α3 subunit. The performance on the novel object recognition task was also impaired. Creatine partially prevented the changes in glutamate uptake and Na⁺,K⁺-ATPase activity, and completely prevented the memory impairment. This study helps to elucidate the protective effects of creatine against the damage caused by GAA.

[Adult Neurogenesis-activating Signals as Therapeutic Targets for Neurodegenerative Disorders]

In most mammalian species, adult neurogenesis appears to occur only in the olfactory bulb and hippocampal dentate gyrus, where neural stem/progenitor cells exist to create new neurons. The discovery of multi-potential neural stem/progenitor cells (NPCs) in the adult brain has precipitated a novel therapeutic strategy for harnessing these endogenous cells to aid in recovery from neurodegenerative disorders. During neurodegeneration, a plethora of endogenous factors, including cytokines, chemokines, neurotransmitters, blood-derived factors, and reactive oxygen species, are released by the activation of resident microglia, astrocytes, and infiltrating peripheral macrophages. It is interesting that these endogenous factors affect the proliferation, migration, differentiation, and survival of newly generated cells involved in the incorporation of newly generated neurons into the brain's circuitry. The unique profile of these endogenous factors can vary the degree of neuroregeneration after neurodegeneration. We show that adult neurogenesis-activating signals are regulated by endogenous factors produced during neurodegeneration.

Pyridine nucleotide-disulphide oxidoreductase domain 2 (PYROXD2): Role in mitochondrial function

Pyridine Nucleotide-Disulphide Oxidoreductase Domain 2 (PYROXD2), a Hepatitis B virus X protein (HBx)-interacting protein, is significantly down-regulated in hepatocellular carcinoma (HCC), however its exact biological function remains unclear. The aim of this study is to investigate the subcellular localization and biological function of PYROXD2 in hepatic cells. The results showed that PYROXD2 was imported to the mitochondrial inner membrane/matrix by Tom40 and Tim23, but not Mia40. PYROXD2 151-230aa might be the mitochondrial targeting sequence. PYROXD2 interacted with complex IV subunit COX5B. Knockout of PYROXD2 decreased MMP, intracellular ROS, complex IV activity, cell proliferation, ATP content and mtDNA copy number, but increased mtROS levels and the number of immature mitochondria. In summary, our data illustrated that PYROXD2 localizes to the mitochondrial inner membrane/matrix, and it plays important roles in regulating mitochondrial function.

Mercury Involvement in Neuronal Damage and in Neurodegenerative Diseases

Neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis are characterized by a chronic and selective process of neuronal cell death. Although the causes of neurodegenerative diseases remain still unknown, it is now a well-established idea that more factors, such as genetic, endogenous, and environmental, are involved. Among environmental causes, the accumulation of mercury, a heavy metal considered a toxic agent, was largely studied as a probable factor involved in neurodegenerative disease course. Mercury exists in three main forms: elemental mercury, inorganic mercury, and organic mercury (methylmercury and ethylmercury). Sources of elemental mercury can be natural (volcanic emission) or anthropogenic (coal-fired electric utilities, waste combustion, hazardous-waste incinerators, and gold extraction). Moreover, mercury is still used as an antiseptic, as a medical preservative, and as a fungicide. Dental amalgam can emit mercury vapor. Mercury vapor, being highly volatile and lipid soluble, can cross the blood-brain barrier and the lipid cell membranes and can be accumulated into the cells in its inorganic forms. Also, methylmercury can pass through blood-brain and placental barriers, causing serious damage in the central nervous system. This review describes the toxic effects of mercury in cell cultures, in animal models, and in patients with neurodegenerative diseases. In vitro experiments showed that mercury exposure was principally involved in oxidative stress and apoptotic processes. Moreover, motor and cognitive impairment and neural loss have been confirmed in various studies performed in animal models. Finally, observational studies on patients with neurodegenerative diseases showed discordant data about a possible mercury involvement.

Functional and structural biomarkers to monitor heavy metal pollution of one of the most contaminated freshwater sites in Southern Europe

This study evaluated the biological effects of highly polluted freshwater environment (Regi Lagni channels, S Italy) on the aquatic moss Leptodictyum riparium, exposed in bags at three sites representative of different environmental conditions and characterized by different heavy metal burdens. Bioaccumulation, ultrastructural alterations, Reactive Oxygen Species (ROS) production, antioxidant enzymes activity and DNA damage were assessed. To better evaluate the biological response of the moss species to heavy metals, the same biological parameters were assessed also in L. riparium samples cultured in vitro using metal mixtures at the same concentrations as measured at the 3 field exposure sites. Heavy metals were accumulated into the moss tissues causing severe ultra-structural damages at higher concentration case studies, and the ROS production as well as the activity of the enzyme followed a concentration-dependent increase. However, the DNA damage trend suggested a threshold effect that changed between field and in vitro experiment. The enrichment factor suggests that the concentration in the most polluted site is close to the upper limit of L. riparium to accumulate metals. Overall, combining measures of the morpho-functional traits at different level contribute to improving the knowledge about the tolerance of L. riparium to heavy metal stress, suggesting that this moss could be suitable for biomonitoring activity in field conditions.

Enriched environment prevents oxidative stress in zebrafish submitted to unpredictable chronic stress

Background

The enriched environment (EE) is a laboratory housing model that emerged from efforts to minimize the impact of environmental conditions on laboratory animals. Recently, we showed that EE promoted positive effects on behavior and cortisol levels in zebrafish submitted to the unpredictable chronic stress (UCS) protocol. Here, we expanded the characterization of the effects of UCS protocol by assessing parameters of oxidative status in the zebrafish brain and reveal that EE protects against the oxidative stress induced by chronic stress.

Methods

Zebrafish were exposed to EE (21 or 28 days) or standard housing conditions and subjected to the UCS protocol for seven days. Oxidative stress parameters (lipid peroxidation (TBARS), reactive oxygen species (ROS) levels, non-protein thiol (NPSH) and total thiol (SH) levels, superoxide dismutase (SOD) and catalase (CAT) activities were measured in brain homogenate.

Results

Our results revealed that UCS increased lipid peroxidation and ROS levels, while decreased NPSH levels and SOD activity, suggesting oxidative damage. EE for 28 days prevented all changes induced by the UCS protocol, and EE for 21 days prevented the alterations on NPSH levels, lipid peroxidation and ROS levels. Both EE for 21 or 28 days increased CAT activity.

Discussion

Our findings reinforce the idea that EE exerts neuromodulatory effects in the zebrafish brain. EE promoted positive effects as it helped maintain the redox homeostasis, which may reduce the susceptibility to stress and its oxidative impact.

Proteomic Changes in Chick Brain Proteome Post Treatment with Lathyrus Sativus Neurotoxin, β-N-Oxalyl-L-α,β-Diaminopropionic Acid (L-ODAP): A Better Insight to Transient Neurolathyrism

Neurolathyrism is a neurodegenerative disorder characterized by spastic paraplegia resulting from the excessive consumption of Lathyrus sativus (Grass pea). β-N-Oxalyl-L-α,β-diaminopropionic acid (L-ODAP) is the primary neurotoxic component in this pea. The present study attempted to evaluate the proteome-wide alterations in chick brain 2 hr and 4 hr post L-ODAP treatment. Proteomic analysis of chick brain homogenates revealed several proteins involved in cytoskeletal structure, signaling, cellular metabolism, free radical scavenging, oxidative stress and neurodegenerative disorders were initially up-regulated at 2 hr and later recovered to normal levels by 4 hr. Since L-ODAP mediated neurotoxicity is mainly by excitotoxicity and oxidative stress related dysfunctions, this study further evaluated the role of L-ODAP in apoptosis in vitro using human neuroblastoma cell line, IMR-32. The in vitro studies carried out at 200 μM L-ODAP for 4 hr indicate minimal intracellular ROS generation and alteration of mitochondrial membrane potential though not leading to apoptotic cell death. L-ODAP at low concentrations can be explored as a stimulator of various reactive oxygen species (ROS) mediated cell signaling pathways not detrimental to cells. Insights from our study may provide a platform to explore the beneficial side of L-ODAP at lower concentrations. This study is of significance especially in view of the Government of India lifting the ban on cultivation of low toxin Lathyrus varieties and consumption of this lentil.

In-field and in-vitro study of the moss Leptodictyum riparium as bioindicator of toxic metal pollution in the aquatic environment: Ultrastructural damage, oxidative stress and HSP70 induction

This study evaluates the effects of toxic metal pollution in the highly contaminated Sarno River (South Italy), by using the aquatic moss Leptodictyum riparium in bags at 3 representative sites of the river. Biological effects were assessed by metal bioaccumulation, ultrastructural changes, oxidative stress, as Reactive Oxygen Species (ROS) production and Glutathione S-transferase (GST) activity, as well as Heat Shock Proteins 70 (HSP70s) induction. The results showed that L. riparium is a valuable bioindicator for toxic metal pollution of water ecosystem, accumulating different amounts of toxic metals from the aquatic environment. Toxic metal pollution caused severe ultrastructural damage, as well as increased ROS production and induction of GST and HSP70s, in the samples exposed at the polluted sites. To assess the role and the effect of toxic metals on L. riparium, were also cultured in vitro with Cd, Cr, Cu, Fe, Ni, Pb, Zn at the same concentrations as measured at the 3 sites. Ultrastructure, ROS, GST, and HSP70s resulted severely affected by toxic metals. Based on our findings, we confirm L. riparium as a model organism in freshwater biomonitoring surveys, and GST and HSP70s as promising biomarkers of metal toxicity.

Physiological and ultrastructural effects of acute ozone fumigation in the lichen Xanthoria parietina: the role of parietin and hydration state

The physiological and ultrastructural effects induced by acute exposure to ozone (O₃) were investigated in the lichen Xanthoria parietina. Our working hypothesis was that parietin content and hydration of the thalli may play a role in the modulation of the effects of O₃ exposure. Four batches of X. parietina samples, dry and wet, with (P+) and without (P-) parietin, were fumigated for 1 h with 3 ppm O₃. The effects of O₃ were assessed immediately after the fumigation and after one week of recovery under controlled conditions. O₃ fumigation caused physiological and ultrastructural impairment both to the photobiont and the mycobiont, irrespective if samples were fumigated wet or dry, and P+ or P-. However, one week after fumigation, a recovery was observed in P+ samples for the photobiont and in dry samples for the mycobiont. We suggest that the hydration state may play a major role in determining the severity of the damage, while the presence of parietin may promote the recovery. Our results provide physiological and ultrastructural basis to explain the ecological insensitivity of lichens to high environmental levels of ozone occurring during dry Mediterranean summers.

Oxidative stress, caspase-3 activation and cleavage of ROCK-1 play an essential role in MeHg-induced cell death in primary astroglial cells

Methylmercury is a toxic environmental contaminant that elicits significant toxicity in humans. The central nervous system is the primary target of toxicity, and is particularly vulnerable during development. Rho-associated protein kinase 1 (ROCK-1) is a major downstream effector of the small GTPase RhoA and a direct substrate of caspase-3. The activation of ROCK-1 is necessary for membrane blebbing during apoptosis. In this work, we examined whether MeHg could affect the RhoA/ROCK-1 signaling pathway in primary cultures of mouse astrocytes. Exposure of cells with 10 μM MeHg decreased cellular viability after 24 h of incubation. This reduction in viability was preceded by a significant increase in intracellular and mitochondrial reactive oxygen species levels, as well as a reduced NAD⁺/NADH ratio. MeHg also induced an increase in mitochondrial-dependent caspase-9 and caspase-3, while the levels of RhoA protein expression were reduced or unchanged. We further found that MeHg induced ROCK-1 cleavage/activation and promoted LIMK1 and MYPT1 phosphorylation, both of which are the best characterized ROCK-1 downstream targets. Inhibiting ROCK-1 and caspases activation attenuated the MeHg-induced cell death. Collectively, these findings are the first to show that astrocytes exposed to MeHg showed increased cleavage/activation of ROCK-1, which was independent of the small GTPase RhoA.

Chinese olive extract ameliorates hepatic lipid accumulation in vitro and in vivo by regulating lipid metabolism

Chinese olive contains plenty of polyphenols, which possess a wide range of biological actions. In this study, we aimed to investigate the role of the ethyl acetate fraction of Chinese olive fruit extract (CO-EtOAc) in the modulation of lipid accumulation in vitro and in vivo. In cellular studies, CO-EtOAc attenuated oleic acid-induced lipid accumulation; we then elucidated the molecular mechanisms of CO-EtOAc in FL83B mouse hepatocytes. CO-EtOAc suppressed the mRNA levels of fatty acid transporter genes (CD36 and FABP) and lipogenesis genes (SREBP-1c, FAS, and ACC1), but upregulated genes that govern lipolysis (HSL) and lipid oxidation (PPARα, CPT-1, and ACOX). Moreover, CO-EtOAc increased the protein expression of phosphorylated AMPK, ACC1, CPT-1, and PPARα, but downregulated the expression of mature SREBP-1c and FAS. AMPK plays an essential role in CO-EtOAc-mediated amelioration of lipid accumulation. Furthermore, we confirmed that CO-EtOAc significantly inhibited body weight gain, epididymal adipose tissue weight, and hepatic lipid accumulation via regulation of the expression of fatty acid transporter, lipogenesis, and fatty acid oxidation genes and proteins in C57BL/6 mice fed a 60% high-fat diet. Therefore, Chinese olive fruits may have the potential to improve the metabolic abnormalities associated with fatty liver under high fat challenge.

Environmental enrichment modulates the response to chronic stress in zebrafish

Several studies have shown that manipulations to the housing environment modulate the susceptibility to stress in laboratory animals, mainly in rodents. Environmental enrichment (EE) is one such manipulation that promotes neuroprotection and neurogenesis, besides affecting behaviors such as drug self-administration. Zebrafish are a popular and useful animal model for behavioral neuroscience studies; however, studies evaluating the impact of housing conditions in this species are scarce. In this study, we verified the effects of EE on behavioral (novel tank test) and biochemical (cortisol and reactive oxygen species (ROS)) parameters in zebrafish submitted to unpredictable chronic stress (UCS). Consistent with our previous findings, UCS increased anxiety-like behavior, cortisol and ROS levels in zebrafish. EE for 21 or 28 days attenuated the effects induced by UCS on behavior and cortisol, and prevented the effects on ROS levels. Our findings reinforce the idea that EE exerts neuromodulatory effects across species, reducing vulnerability to stress and its biochemical impact. Also, these results indicate that zebrafish is a suitable model animal to study the behavioral effects and neurobiological mechanisms related to EE.

Lung Oxidative Stress, DNA Damage, Apoptosis, and Fibrosis in Adenine-Induced Chronic Kidney Disease in Mice

It is well-established that there is a crosstalk between the lung and the kidney, and several studies have reported association between chronic kidney disease (CKD) and pulmonary pathophysiological changes. Experimentally, CKD can be caused in mice by dietary intake of adenine. Nevertheless, the consequence of such intervention on the lung received only scant attention. Here, we assessed the pulmonary effects of adenine (0.2% w/w in feed for 4 weeks)-induced CKD in mice by assessing various physiological histological and biochemical endpoints. Adenine treatment induced a significant increase in urine output, urea and creatinine concentrations, and it decreased the body weight and creatinine clearance. It also increased proteinuria and the urinary levels of kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin. Compared with control group, the histopathological evaluation of lungs from adenine-treated mice showed polymorphonuclear leukocytes infiltration in alveolar and bronchial walls, injury, and fibrosis. Moreover, adenine caused a significant increase in lung lipid peroxidation and reactive oxygen species and decreased the antioxidant catalase. Adenine also induced DNA damage assessed by COMET assay. Similarly, adenine caused apoptosis in the lung characterized by a significant increase of cleaved caspase-3. Moreover, adenine induced a significant increase in the expression of nuclear factor erythroid 2–related factor 2 (Nrf2) in the lung. We conclude that administration of adenine in mice induced CKD is accompanied by lung oxidative stress, DNA damage, apoptosis, and Nrf2 expression and fibrosis.

Synergistic Toxicity of the Neurometabolites Quinolinic Acid and Homocysteine in Cortical Neurons and Astrocytes: Implications in Alzheimer's Disease

The brain of patients affected by Alzheimer's disease (AD) develops progressive neurodegeneration linked to the formation of proteins aggregates. However, their single actions cannot explain the extent of brain damage observed in this disorder, and the characterization of co-adjuvant involved in the early toxic processes evoked in AD is essential. In this line, quinolinic acid (QUIN) and homocysteine (Hcy) appear to be involved in the AD neuropathogenesis. Herein, we investigate the effects of QUIN and Hcy on early toxic events in cortical neurons and astrocytes. Exposure of primary cortical cultures to these neurometabolites for 24 h induced concentration-dependent neurotoxicity. In addition, QUIN (25 μM) and Hcy (30 μM) triggered ROS production, lipid peroxidation, diminished of Na⁺,K⁺-ATPase activity, and morphologic alterations, culminating in reduced neuronal viability by necrotic cell death. In astrocytes, QUIN (100 μM) and Hcy (30 μM) induced caspase-3-dependent apoptosis and morphologic alterations through oxidative status imbalance. To establish specific mechanisms, we preincubated cell cultures with different protective agents. The combined toxicity of QUIN and Hcy was attenuated by melatonin and Trolox in neurons and by NMDA antagonists and glutathione in astrocytes. Cellular death and morphologic alterations were prevented when co-culture was treated with metabolites, suggesting the activation of protector mechanisms dependent on soluble factors and astrocyte and neuron communication through gap junctions. These findings suggest that early damaging events involved in AD can be magnified by synergistic toxicity of the QUIN and Hcy. Therefore, this study opens new possibilities to elucidate the molecular mechanisms of neuron-astrocyte interactions and their role in neuroprotection against QUIN and Hcy.

Effects of triacontanol on ascorbate-glutathione cycle in Brassica napus L. exposed to cadmium-induced oxidative stress

The ability of exogenous triacontanol (TRIA), a plant growth regulator, to reduce Cd toxicity was studied in canola (Brassica napus L.) plants. The following biological parameters were examined in canola seedlings to investigate TRIA-induced tolerance to Cd toxicity: seedling growth, chlorophyll damage and antioxidant response. In particular, TRIA application reduced Cd-induced oxidative damage, as shown by reduction of ROS content, lipoxygenase (LOX) activity and lipid peroxidation level. TRIA pretreatment increased non-enzymatic antioxidant contents (ascorbate, AsA, glutathione and GSH), phytochelatin content (PCs) and activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), monodehydroascorbate reductase (MDHAR), dehydro ascorbate reductase (DHAR), and glutathione reductase (GR), so reducing the oxidative stress. These results clearly indicate the protective ability of TRIA to modulate the redox status through the antioxidant pathway AGC and GSH, so reducing Cd-induced oxidative stress.

Toxic Synergism Between Quinolinic Acid and Glutaric Acid in Neuronal Cells Is Mediated by Oxidative Stress: Insights to a New Toxic Model

It has been shown that synergistic toxic effects of quinolinic acid (QUIN) and glutaric acid (GA), both in isolated nerve endings and in vivo conditions, suggest the contribution of these metabolites to neurodegeneration. However, this synergism still requires a detailed characterization of the mechanisms involved in cell damage during its occurrence. In this study, the effects of subtoxic concentrations of QUIN and/or GA were tested in neuronal cultures, co-cultures (neuronal cells + astrocytes), and mixed cultures (neuronal cells + astrocytes + microglia) from rat cortex and striatum. The exposure of different cortical and striatal cell cultures to QUIN + GA resulted in cell death and stimulated different markers of oxidative stress, including reactive oxygen species (ROS) formation; changes in the activity of antioxidant enzymes such as superoxide dismutase, catalase, and glutathione peroxidase; and depletion of endogenous antioxidants such as -SH groups and glutathione. The co-incubation of neuronal cultures with QUIN + GA plus the N-methyl-D-aspartate antagonist MK-801 prevented cell death but not ROS formation, whereas the antioxidant melatonin reduced both parameters. Our results demonstrated that QUIN and GA can create synergistic scenarios, inducing toxic effects on some parameters of cell viability via the stimulation of oxidative damage. Therefore, it is likely that oxidative stress may play a major causative role in the synergistic actions exerted by QUIN + GA in a variety of cell culture conditions involving the interaction of different neural types.

Exposure to Electrophiles Impairs Reactive Persulfide-Dependent Redox Signaling in Neuronal Cells

Electrophiles such as methylmercury (MeHg) affect cellular functions by covalent modification with endogenous thiols. Reactive persulfide species were recently reported to mediate antioxidant responses and redox signaling because of their strong nucleophilicity. In this study, we used MeHg as an environmental electrophile and found that exposure of cells to the exogenous electrophile elevated intracellular concentrations of the endogenous electrophilic molecule 8-nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP), accompanied by depletion of reactive persulfide species and 8-SH-cGMP which is a metabolite of 8-nitro-cGMP. Exposure to MeHg also induced S-guanylation and activation of H-Ras followed by injury to cerebellar granule neurons. The electrophile-induced activation of redox signaling and the consequent cell damage were attenuated by pretreatment with a reactive persulfide species donor. In conclusion, exogenous electrophiles such as MeHg with strong electrophilicity impair the redox signaling regulatory mechanism, particularly of intracellular reactive persulfide species and therefore lead to cellular pathogenesis. Our results suggest that reactive persulfide species may be potential therapeutic targets for attenuating cell injury by electrophiles.

Activator protein-1 (AP-1): a bridge between life and death in lung epithelial (A549) cells under hypoxia

Activator protein-1 (AP-1) transcription factor plays a central role in hypoxia to modulate the expression of genes that decides the fate of the cell. The aim of the present study was to explore the role of AP-1 subunits in lung epithelial (A549) cells under hypoxia. Cell cycle studies by flow cytometry indicated that cell viability was unaffected by the initial hypoxia exposure (0.5% O₂ at 37 °C) for 6 and 12 h. However, both transient cell cycle arrest and cell death was detected at 24 and 48 h. Flow cytometry and spectrofluorometry data confirmed the increase in ROS levels. Elevated ROS and calcium levels activated the stress-related MAPK signaling cascade. ERK and JNK were activated in early hypoxic exposure (within 6 h), whereas p38 were activated in 48 h of hypoxia. These subtypes further stimulated the subunits of AP-1 at different times of hypoxia exposure to orchestrate different genes responsible for cell proliferation (6 and 12 h) and apoptosis (24 and 48 h). Our results clearly depict the role of AP-1 heterodimer, i.e., p-c-jun/c-fos, p-c-jun/fosB, junD/c-fos, and junD/fosB in cell proliferation/survival by regulating the expression of Bcl-2 and cyclins (D1 and B1) at 6 h and 12 h of hypoxia, whereas junB/Fra-1 heterodimer have important role in apoptosis by regulating the expression of p53, Bax, and cyclin-dependent kinase inhibitors (p16, p21, p27) at 24 h and 48 h of hypoxia. Also, the cell survival signaling pathway NO-AKT interrupted at 24 h and 48 h of hypoxia indicating cell death. In conclusion, hypoxia for different time points activated different subunits of AP-1 that combined to form different heterodimers. These dimers regulated the expression of genes responsible for cell proliferation and apoptosis. Since, AP-1 plays a role in the decisive phenomenon of the cell to choose between proliferation and apoptosis; thus, its subunits or dimers could be a good therapeutic target for many diseases.

Effect of tannery effluent on oxidative status of brain structures and liver of rodents

Oxidative stress has been considered as a central mechanism of toxicity induced by xenobiotics. Previously, it was demonstrated that mice exposed to tannery effluent showed an anxiety-like behavior, without any comparable behavioral effects in rats. The aim of the present study was to investigate the impact of tannery wastewater on oxidative status in in vitro and in vivo assays with two mammal species, mice and rats. Specifically, homogenates of two brain areas and the liver were incubated with tannery wastewater; reactive species and lipid peroxidation levels and antioxidant enzyme activities were detected. In addition, the effects of in vivo exposure of mice to tannery effluents on and lipid peroxidation levels and the total reactive antioxidant capacity in brain areas and liver. Brain areas, the hippocampus and frontal cortex, and the liver of mice exposed to tannery wastewater showed oxidative stress. Our data suggest that divergent species-dependent hepatic enzymes adaptations, such as glutathione peroxidase and glutathione S-transferase activities, induced by tannery effluent could explain previous behavioral findings.

Effects of Dendropanax morbifera Léveille extract on hypothyroidism-induced oxidative stress in the rat hippocampus

In this experiment, we verified the effects of Dendropanax morbifera Léveille stem extract (DMS) on hypothyroidism-induced oxidative stress in the hippocampus of rats. Hypothyroidism was induced in rats by treating them with 0.03% 2-mercapto-1-methyl-imidazole dissolved in drinking water for 5 weeks. DMS (100 mg/kg) was also orally administered to the rats during the same period and the animals were sacrificed at 12 weeks of age. DMS administration tended to ameliorate these hypothyroidism-induced changes in serum triiodothyronine (T₃), thyroxine (T₄), and thyroid-stimulating hormone levels. DMS administration significantly reduced the hypothyroidism-induced increases in reactive oxygen species production as well as in lipid peroxidation in the hippocampus. In addition, DMS administration increased hippocampal Cu, Zn-superoxide dismutase (SOD1), catalase (CAT), and glutathione peroxidase (GPx) levels. These results suggest that DMS potentially ameliorates hypothyroidism-induced neuroendocrine phenotypes and oxidative stress in the hippocampus via the induction of antioxidant enzymes.

Heavy metals (Pb, Cd, As and MeHg) as risk factors for cognitive dysfunction: A general review of metal mixture mechanism in brain

Human exposure to toxic heavy metals is a global challenge. Concurrent exposure of heavy metals, such as lead (Pb), cadmium (Cd), arsenic (As) and methylmercury (MeHg) are particularly important due to their long lasting effects on the brain. The exact toxicological mechanisms invoked by exposure to mixtures of the metals Pb, Cd, As and MeHg are still unclear, however they share many common pathways for causing cognitive dysfunction. The combination of metals may produce additive/synergetic effects due to their common binding affinity with NMDA receptor (Pb, As, MeHg), Na⁺ - K⁺ ATP-ase pump (Cd, MeHg), biological Ca⁺² (Pb, Cd, MeHg), Glu neurotransmitter (Pb, MeHg), which can lead to imbalance between the pro-oxidant elements (ROS) and the antioxidants (reducing elements). In this process, ROS dominates the antioxidants factors such as GPx, GS, GSH, MT-III, Catalase, SOD, BDNF, and CERB, and finally leads to cognitive dysfunction. The present review illustrates an account of the current knowledge about the individual metal induced cognitive dysfunction mechanisms and analyse common Mode of Actions (MOAs) of quaternary metal mixture (Pb, Cd, As, MeHg). This review aims to help advancement in mixture toxicology and development of next generation predictive model (such as PBPK/PD) combining both kinetic and dynamic interactions of metals.

Methylphenidate Decreases ATP Levels and Impairs Glutamate Uptake and Na+,K+-ATPase Activity in Juvenile Rat Hippocampus

The study of the long-term neurological consequences of early exposure with methylphenidate (MPH) is very important since this psychostimulant has been widely misused by children and adolescents who do not meet full diagnostic criteria for ADHD. The aim of this study was to examine the effect of early chronic exposure with MPH on amino acids profile, glutamatergic and Na⁺,K⁺-ATPase homeostasis, as well as redox and energy status in the hippocampus of juvenile rats. Wistar male rats received intraperitoneal injections of MPH (2.0 mg/kg) or saline solution (controls), once a day, from the 15th to the 45th day of age. Results showed that MPH altered amino acid profile in the hippocampus, decreasing glutamine levels. Glutamate uptake and Na⁺,K⁺-ATPase activity were decreased after chronic MPH exposure in the hippocampus of rats. No changes were observed in the immunocontents of glutamate transporters (GLAST and GLT-1), and catalytic subunits of Na⁺,K⁺-ATPase (α₁, α₂, and α₃), as well as redox status. Moreover, MPH provoked a decrease in ATP levels in the hippocampus of chronically exposed rats, while citrate synthase, succinate dehydrogenase, respiratory chain complexes activities (II, II-III, and IV), as well as mitochondrial mass and mitochondrial membrane potential were not altered. Taken together, our results suggest that chronic MPH exposure at early age impairs glutamate uptake and Na⁺,K⁺-ATPase activity probably by decreasing in ATP levels observed in rat hippocampus.

Chitosan attenuates dibutyltin-induced apoptosis in PC12 cells through inhibition of the mitochondria-dependent pathway

Dibutyltin (DBT) which was widely used as biocide and plastic stabilizer has been described as a potent neurotoxicant. Chitosan (CS), a natural nontoxic biopolymer, possesses a variety of biological activities including antibacterial, antifungal, free radical scavenging and neuroprotective activities. The present study was undertaken to investigate the protective effects of CS against DBT-induced apoptosis in rat pheochromocytoma (PC12) cells and the underlying mechanisms in vitro. Our results demonstrated that pretreatment with CS significantly increased the cell viability and decreased lactate dehydrogenase (LDH) release induced by DBT in a dose-dependent manner. Meanwhile, DBT-induced cell apoptosis, mitochondrial membrane potential (MMP) disruption, and generation of intracellular reactive oxygen species (ROS) were attenuated by CS. Real-time PCR assay showed that DBT markedly enhanced the mRNA levels of Bax, Bad, cytochrome-c and Apaf-1, reduced the Bcl-2 and Bcl-xL mRNA levels, while these genes expression alteration could be partially reversed by CS treatment. Furthermore, CS also inhibited the DBT-inducted activation of caspase-9, and -3 at mRNA and protein expression levels. Taken together, these results suggested that CS could protect the PC12 cells from apoptosis induced by DBT through inhibition of the mitochondria-dependent pathway.