Mechanism of KAT2A regulation of H3K36ac in manganese-induced oxidative damage to mitochondria in the nervous system and intervention by curcumin

Excessive exposure to manganese in the environment or workplace is strongly linked to neurodegeneration and cognitive impairment, but the precise pathogenic mechanism and preventive measures are still not fully understood. The study aimed to investigate manganese -induced oxidative damage in the nervous system from an epigenetic perspective, focusing on the H3K36ac-dependent antioxidant pathway. Additionally, it sought to examine the potential of curcumin in preventing manganese-induced oxidative damage. Histopathology and transmission electron microscopy revealed that apoptosis and necrosis of neurons and mitochondrial ultrastructure damage were observed in the striatum of manganese-exposed rats. manganese suppressed the expression of mitochondrial antioxidant genes, leading to oxidative damage in the rats' striatum and SH-SY5Y cells. With higher doses of manganese, levels of histone acetyltransferase lysine acetyltransferase 2 A (KAT2A) expression and H3K36ac level decreased. ChIP-qPCR confirmed that H3K36ac enrichment in the promoter regions of antioxidant genes SOD2, PRDX3, and TXN2 was reduced in SH-SY5Y cells after manganese exposure, leading to decreased expression of these genes. Overexpression of KAT2A confirms that it attenuates manganese-induced mitochondrial oxidative damage by regulating H3K36ac levels, which in turn controls the expression of antioxidant genes SOD2, PRDX3, and TXN2 in the manganese-exposed cell model. Furthermore, curcumin might control H3K36ac levels by influencing KAT2A expression, boosting antioxidant genes expression, and reducing manganese-induced mitochondrial oxidative damage. In conclusion, the regulation of mitochondrial oxidative stress by histone acetylation may be an important mechanism of manganese-induced neurotoxicity. This regulation could be achieved by reducing the level of H3K36ac near the promoter region of mitochondrial-associated antioxidant genes via KAT2A. Curcumin mitigates manganese-induced oxidative damage in mitochondria and plays a crucial protective role in manganese-induced oxidative injury in the nervous system.

Neuroprotective Effect of Resveratrol against Manganese-Induced Oxidative Stress and Matrix Metalloproteinase-9 in an "In Vivo" Model of Neurotoxicity

Chronic exposure to manganese (Mn) leads to its accumulation in the central nervous system (CNS) and neurotoxicity with not well-known mechanisms. We investigated the involvement of matrix metalloproteinase (MMP)-2 and -9 in Mn neurotoxicity in an in vivo model of rats treated through an intraperitoneal injection, for 4 weeks, with 50 mg/kg of MnCl2 in the presence or in the absence of 30 mg/kg of resveratrol (RSV). A loss of weight was observed in Mn-treated rats compared with untreated and RSV-treated rats. A progressive recovery of body weight was detected in rats co-treated with Mn and RSV. The analysis of brain homogenates indicated that RSV counteracted the Mn-induced increase in MMP-9 levels and reactive oxygen species production as well as the Mn-induced decrease in superoxide dismutase activity and glutathione content. In conclusion, Mn exposure, resulting in MMP-9 induction with mechanisms related to oxidative stress, represents a risk factor for the development of CNS diseases.

Heavy Metal Exposure: Molecular Pathways, Clinical Implications, and Protective Strategies

Heavy metals are often found in soil and can contaminate drinking water, posing a serious threat to human health. Molecular pathways and curation therapies for mitigating heavy metal toxicity have been studied for a long time. Recent studies on oxidative stress and aging have shown that the molecular foundation of cellular damage caused by heavy metals, namely, apoptosis, endoplasmic reticulum stress, and mitochondrial stress, share the same pathways as those involved in cellular senescence and aging. In recent aging studies, many types of heavy metal exposures have been used in both cellular and animal aging models. Chelation therapy is a traditional treatment for heavy metal toxicity. However, recently, various antioxidants have been found to be effective in treating heavy metal-induced damage, shifting the research focus to investigating the interplay between antioxidants and heavy metals. In this review, we introduce the molecular basis of heavy metal-induced cellular damage and its relationship with aging, summarize its clinical implications, and discuss antioxidants and other agents with protective effects against heavy metal damage.

The oleic/palmitic acid imbalance in exosomes isolated from NAFLD patients induces necroptosis of liver cells via the elongase-6/RIP-1 pathway

Excessive toxic lipid accumulation in hepatocytes underlies the development of non-alcoholic fatty liver disease (NAFLD), phenotypically characterized by necrosis and steato-fibrosis, whose molecular mechanism is not yet fully understood. Patients with NAFLD display an imbalanced palmitic (PA) to oleic acid (OA) ratio. Moreover, increasing experimental evidence points out a relevant involvement of the exosomal content in disease progression. Aim of the study was to highlight the PA/OA imbalance within circulating exosomes, the subsequent intracellular alterations, and the impact on NALFD. Liver cells were challenged with exosomes isolated from both healthy subjects and NAFLD patients. The exosomal PA/OA ratio was artificially modified, and biological effects were evaluated. A NAFLD-derived exosomal PA/OA imbalance impacts liver cell cycle and cell viability. OA-modified NAFLD-derived exosomes restored cellular viability and proliferation, whereas the inclusion of PA into healthy subjects-derived exosomes negatively affected cell viability. Moreover, while OA reduced the phosphorylation and activation of the necroptosis marker, Receptor-interacting protein 1 (phospho-RIP-1), PA induced the opposite outcome, alongside increased levels of stress fibers, such as vimentin and fibronectin. Administration of NAFLD-derived exosomes led to increased expression of Elongase 6 (ELOVL6), Stearoyl-CoA desaturase 1 (SCD1), Tumor necrosis factor α (TNF-α), Mixed-lineage-kinase-domain-like-protein (MLKL) and RIP-1 in the hepatocytes, comparable to mRNA levels in the hepatocytes of NAFLD patients reported in the Gene Expression Omnibus (GEO) database. Genetic and pharmacological abrogation of ELOVL6 elicited a reduced expression of downstream molecules TNF-α, phospho-RIP-1, and phospho-MLKL upon administration of NAFLD-derived exosomes. Lastly, mice fed with high-fat diet exhibited higher phospho-RIP-1 than mice fed with control diet. Targeting the Elongase 6-RIP-1 signaling pathway offers a novel therapeutic approach for the treatment of the NALFD-induced exosomal PA/OA imbalance.

Manganese Exposure Induces Cellular Aggregates and the Accumulation of β-Catenin in Skin of Zebrafish Embryos

The effects of manganese (Mn) toxicity in different organs and tissues in humans and other vertebrates have been studied since the beginning of the past century, but most of its cellular effects remain largely unknown. In this study, we studied the effects of Mn in zebrafish, at the cellular level, due to the transparent nature of zebrafish larvae that enables a powerful analysis under the light microscope. The collection of our results shows that environmental concentrations of 0.5 mg/L affect swim bladder inflation; at concentration of 50 and 100 mg/L Mn (1) induces alterations in viability, swim bladder, heart, and size of zebrafish larvae, (2) induces an increase in melanocyte area and the formation of cellular aggregates in the skin, and (3) induces an accumulation of β-Catenin in mesenchymal cells in the caudal fin of zebrafish larvae. Our data suggest that increased levels of Mn induce cell aggregate formation in the skin and the presence of more melanocytes in the zebrafish caudal fin. Interestingly, the adhesion protein β-Catenin was activated in mesenchymal cells near the cell aggregates. These results open important new questions on the role of Mn toxicity on cellular organization and β-Catenin responses in fishes.

Brain Protective Effect of Resveratrol via Ameliorating Interleukin-1β-Induced MMP-9-Mediated Disruption of ZO-1 Arranged Integrity

In the central nervous system (CNS), the matrix metalloproteinase-9 (MMP-9) is induced by several factors and contributes to CNS disorders, including inflammation and neurodegeneration. Thus, the upregulation of MMP-9 has been considered to be an indicator of inflammation. Interleukin-1β (IL-1β) is an important proinflammatory cytokine which can induce various inflammatory factors, such as MMP-9, in many inflammatory disorders. Several phytochemicals are believed to reduce the risk of several inflammatory disorders, including the CNS diseases. Among them, the resveratrol, a principal phenolic compound of the grape, blueberry, and mulberry peels and Cassia plants, has been shown to possess several medicinal properties, including antioxidative, anti-inflammatory, and antitumor function. Herein, we used mouse-brain microvascular endothelial cells (bMECs) to demonstrate the signaling mechanisms of IL-1β-induced MMP-9 expression via zymographic, RT-PCR, Western blot, reactive oxygen species (ROS) detection, immunofluorescence stain, and promoter reporter analyses. Then we evaluated the effects of resveratrol on IL-1β-induced MMP-9 expression in bMECs and its mechanism of action. We first demonstrated that IL-1β induced MMP-9 expression in bMECs. Subsequently, IL-1β induced MMP-9 expression via ROS-mediated c-Src-dependent transactivation of EGFR, and then activation of the ERK1/2, p38 MAPK, JNK1/2, and NF-κB signaling pathway. Finally, we determined that IL-1β-induced upregulation of MMP-9 may cause the disruption of the arranged integrity of zonula occludens-1 (ZO-1), but this could be inhibited by resveratrol. These data indicated that resveratrol may have antioxidative and brain-protective activities by reducing these related pathways of ROS-mediated MMP-9 expression and tight junction disruption in brain microvascular endothelial cells.

A Novel Selenium Polysaccharide Alleviates the Manganese (Mn)-Induced Toxicity in Hep G2 Cells and Caenorhabditis elegans

Manganese (Mn) is now known to have a variety of toxicities, particularly when exposed to it in the workplace. However, there are still ineffective methods for reducing Mn's hazardous effects. In this study, a new selenium polysaccharide (Se-PCS) was developed from the shell of Camellia oleifera to reduce Mn toxicity in vitro and in vivo. The results revealed that Se-PCS may boost cell survival in Hep G2 cells exposed to Mn and activate antioxidant enzyme activity, lowering ROS and cell apoptosis. Furthermore, after being treated with Se-PCS, Caenorhabditis elegans survived longer under Mn stress. daf-16, a tolerant critical gene, was turned on. Moreover, the antioxidant system was enhanced as the increase in strong antioxidant enzyme activity and high expression of the sod-3, ctl-2, and gst-1 genes. A variety of mutations were also used to confirm that Se-PCS downregulated the insulin signaling pathway. These findings showed that Se-PCS protected Hep G2 cells and C. elegans via the insulin/IGF-1 signaling pathway and that it could be developed into a promising medication to treat Mn toxicity.

Protective effect of calpain inhibitors against manganese-induced toxicity in rats

Development of manganism is a major complication of manganese exposure in which neurological dysfunction is linked to accumulation of metal in the brain. Current therapies do not prevent progression of the disease. Therefore, development of effective therapeutic strategies for treatment of manganism is of utmost importance. Since the hyperactivation of calpain family proteases in CNS during manganism in an animal model is observed, we assumed that inhibition of calpains can suppress the development of Mn-induced neurological disturbances. The goal of this study is to delineate protective effect and the mechanism of neuroprotection of calpain inhibitor in rat model of Mn-induced neurological symptoms. Using the Gait analysis test, we found that chronic intranasal administration of the calpain inhibitor Cast (184-210) (peptide, which is corresponding to the 184-210 amino acid of the endogenous inhibitor of calpains-human calpastatin) to Mn-treated rats contributed to a significant decrease in the severity of gait disorders, although it did not lead to a decrease in the Mn deposition in the striatum and hippocampus. Accordingly to the results of PCR-RT, this effect was accompanied by a partial reduction in the content of neuro-inflammatory markers (IL-1β, TNF-α, NFκB mRNA in the hippocampus and, additionally, IBA-1 mRNA in the striatum), as well as normalization of the content of dopamine and its metabolites in the hippocampus and striatum, which was assessed by HPLC. In striatum cells, the application of Cast (184-210) also led to a significant increase in the production of tyrosine hydroxylase, which was analyzed by immunoblotting method. These findings suggest that calpain inhibitors may be a valid therapeutic agent in manganism.

N-Acetylcysteine Ameliorates Neurotoxic Effects of Manganese Intoxication in Rats: A Biochemical and Behavioral Study

Clinical and experimental evidences reveal that excess exposure to manganese is neurotoxic and leads to cellular damage. However, the mechanism underlying manganese neurotoxicity remains poorly understood but oxidative stress has been implicated to be one of the key pathophysiological features related to it. The present study investigates the effects associated with manganese induced toxicity in rats and further to combat these alterations with a well-known antioxidant N-acetylcysteine which is being used in mitigating the damage by its radical scavenging activity. The study was designed to note the sequential changes along with the motor and memory dysfunction associated with biochemical and histo-pathological alterations following exposure and treatment for 2 weeks. The results so obtained showed decrease in the body weights, behavioral deficits with increased stress markers and also neuronal degeneration in histo-pathological examination after manganese intoxication in rats. To overcome the neurotoxic effects of manganese, N-acetylcysteine was used in the current study due to its pleiotropic potential in several pathological ailments. Taken together, N-acetylcysteine helped in ameliorating manganese induced neurotoxic effects by diminishing the behavioral deficits, normalizing acetylcholinesterase activity, and augmentation of redox status.

Effects of resveratrol on female reproduction: A review

The present review summarizes the current knowledge concerning physiological effects of resveratrol (RSV) with emphasis on the RSV action on female reproductive processes. The review outlines provenance, properties, mechanisms of action, physiological and therapeutic actions of RSV on female reproduction and other physiological processes, as well as areas of possible application of R. This review is based on the search for the related full papers indexed in Medline/Pubmed, Web of Science and SCOPUS databases between the year 2000 and 2021 according to the criteria of preferred reporting items for systematic reviews and meta-analyses extension for scoping reviews and other related guidelines. The analysis of the available information suggests that RSV has a number of properties which enable its influence on various physiological processes including female reproduction at various regulatory levels via various extra- and intracellular signalling pathways. Despite some contradictions and limitations in the available data, they indicate applicability of both stimulatory and inhibitory effects of RSV for control and influence of various reproductive and non-reproductive processes and treatment of their disorders in phytotherapy, animal production, medicine, biotechnology and assisted reproduction. To establish the clinical efficacy of RSV, further high quality studies are needed.

Systemic Exposure to Air Pollution Induces Oxidative Stress and Inflammation in Mouse Brain, Contributing to Neurodegeneration Onset

In northern Italy, biomass burning-derived (BB) particles and diesel exhaust particles (DEP) are considered the most significant contributors to ultrafine particle (UFP) emission. However, a comparison between their impact on different brain regions was not investigated until now. Therefore, male BALB/c mice were treated with a single or three consecutive intratracheal instillations using 50 µg of UFPs in 100 µL of isotonic saline solution or 100 µL of isotonic saline solution alone, and brains were collected and analyzed. Proteins related to oxidative stress and inflammation, as well as Alzheimer's disease markers, were examined in the hippocampus, cerebellum, and the rest of the brain (RoB). Histopathological examination of the brain was also performed. Moreover, correlations among different brain, pulmonary, and cardiovascular markers were performed, allowing us to identify the potentially most stressful UFP source. Although both acute exposures induced inflammatory pathways in mouse brain, only DEP showed strong oxidative stress. The sub-acute exposure also induced the modulation of APP and BACE1 protein levels for both UFPs. We observed that DEP exposure is more harmful than BB, and this different response could be explained by this UFP's different chemical composition and reactivity.

Additive Effect of Resveratrol on Astrocyte Swelling Post-exposure to Ammonia, Ischemia and Trauma In Vitro

Swelling of astrocytes represents a major component of the brain edema associated with many neurological conditions, including acute hepatic encephalopathy (AHE), traumatic brain injury (TBI) and ischemia. It has previously been reported that exposure of cultured astrocytes to ammonia (a factor strongly implicated in the pathogenesis of AHE), oxygen/glucose deprivation, or to direct mechanical trauma results in an increase in cell swelling. Since dietary polyphenols have been shown to exert a protective effect against cell injury, we examined whether resveratrol (RSV, 3,5,4'-trihydroxy-trans-stilbene, a stilbenoid phenol), has a protective effect on astrocyte swelling following its exposure to ammonia, oxygen-glucose deprivation (OGD), or trauma in vitro. Ammonia increased astrocyte swelling, and pre- or post-treatment of astrocytes with 10 and 25 µM RSV displayed an additive effect, while 5 µM did not prevent the effect of ammonia. However, pre-treatment of astrocytes with 25 µM RSV slightly, but significantly, reduced the trauma-induced astrocyte swelling at earlier time points (3 h), while post-treatment had no significant effect on the trauma-induced cell swelling at the 3 h time point. Instead, pre- or post-treatment of astrocytes with 25 µM RSV had an additive effect on trauma-induced astrocyte swelling. Further, pre- or post-treatment of astrocytes with 5 or 10 µM RSV had no significant effect on trauma-induced astrocyte swelling. When 5 or 10 µM RSV were added prior to, or during the process of OGD, as well as post-OGD, it caused a slight, but not statistically significant decline in cell swelling. However, when 25 µM RSV was added during the process of OGD, as well as after the cells were returned to normal condition (90 min period), such treatment showed an additive effect on the OGD-induced astrocyte swelling. Noteworthy, a higher concentration of RSV (25 µM) exhibited an additive effect on levels of phosphorylated forms of ERK1/2, and p38^MAPK, as well as an increased activity of the Na⁺-K⁺-Cl^- co-transporter-1 (NKCC1), factors known to induce astrocytes swelling, when the cells were treated with ammonia or after trauma or ischemia. Further, inhibition of ERK1/2, and p38^MAPK diminished the RSV-induced exacerbation of cell swelling post-ammonia, trauma and OGD treatment. These findings strongly suggest that treatment of cultured astrocytes with RSV enhanced the ammonia, ischemia and trauma-induced cell swelling, likely through the exacerbation of intercellular signaling kinases and ion transporters. Accordingly, caution should be exercised when using RSV for the treatment of these neurological conditions, especially when brain edema is also suspected.

In Vivo Comparative Study on Acute and Sub-acute Biological Effects Induced by Ultrafine Particles of Different Anthropogenic Sources in BALB/c Mice

Exposure to ultrafine particles (UFPs) leads to adverse effects on health caused by an unbalanced ratio between UFPs deposition and clearance efficacy. Since air pollution toxicity is first direct to cardiorespiratory system, we compared the acute and sub-acute effects of diesel exhaust particles (DEP) and biomass burning-derived particles (BB) on bronchoalveolar Lavage Fluid (BALf), lung and heart parenchyma. Markers of cytotoxicity, oxidative stress and inflammation were analysed in male BALB/c mice submitted to single and repeated intra-tracheal instillations of 50 μg UFPs. This in-vivo study showed the activation of inflammatory response (COX-2 and MPO) after exposure to UFPs, both in respiratory and cardiovascular systems. Exposure to DEP results also in pro- and anti-oxidant (HO-1, iNOS, Cyp1b1, Hsp70) protein levels increase, although, stress persist only in cardiac tissue under repeated instillations. Statistical correlations suggest that stress marker variation was probably due to soluble components and/or mediators translocation of from first deposition site. This mechanism, appears more important after repeated instillations, since inflammation and oxidative stress endure only in heart. In summary, chemical composition of UFPs influenced the activation of different responses mediated by their components or pro-inflammatory and pro-oxidative molecules, indicating DEP as the most damaging pollutant in the comparison.

Subchronic Manganese Exposure Impairs Neurogenesis in the Adult Rat Hippocampus

Adult neurogenesis takes place in the brain subventricular zone (SVZ) in the lateral walls of lateral ventricles and subgranular zone (SGZ) in the hippocampal dentate gyrus (HDG), and functions to supply newborn neurons for normal brain functionality. Subchronic Mn exposure is known to disrupt adult neurogenesis in the SVZ. This study was designed to determine whether Mn exposure disturbed neurogenesis within the adult HDG. Adult rats (10 weeks old) received a single dose of bromodeoxyuridine (BrdU) at the end of 4-week Mn exposure to label the proliferating cells. Immunostaining and cell counting data showed that BrdU(+) cells in Mn-exposed HDG were about 37% lower than that in the control (p < .05). The majority of BrdU(+) cells were identified as Sox2(+) cells. Another set of adult rats received BrdU injections for 3 consecutive days followed by 2- or 4-week Mn exposure to trace the fate of BrdU-labeled cells in the HDG. The time course studies indicated that Mn exposure significantly reduced the survival rate (54% at 2 weeks and 33% at 4 weeks), as compared with that in the control (80% at 2 weeks and 51% at 4 weeks) (p < .01). A significant time-dependent migration of newborn cells from the SGZ toward the granule cell layer was also observed in both control and Mn-exposed HDG. Triple-stained neuroblasts and mature neurons further revealed that Mn exposure significantly inhibited the differentiation of immature neuroblasts into mature neurons in the HDG. Taken together, these observations suggest that subchronic Mn exposure results in a reduced cell proliferation, diminished survival of adult-born neurons, and inhibited overall neurogenesis in the adult HDG. Impaired adult neurogenesis is likely one of the mechanisms contribute to Mn-induced Parkinsonian disorder.

In vitro effect of antiretroviral drugs on cultured primary astrocytes: analysis of neurotoxicity and matrix metalloproteinase inhibition

There is little information available on the possible toxic effects that antiretroviral (ARV) drugs used for the treatment of human immunodeficiency virus (HIV)-infected subjects, may have on the central nervous system (CNS) resident cells. Moreover, it remains unclear whether the efficacy of the ARV drugs may also be due to their ability to exert extravirological effects on factors responsible for the development of HIV brain injury, e.g., matrix metalloproteinases (MMPs). This study investigates the toxicity of three different ARV drugs and on their ability to modulate levels and expression of gelatinases A (MMP-2) and B (MMP-9) in astrocytes. Primary cultures of rat astrocytes were activated by exposure to lipopolysaccaride (LPS) and simultaneously treated with darunavir, maraviroc, or raltegravir, used alone or in combination. Among the tested drugs, maraviroc was the less toxic for astrocytes. At toxic concentration (TC₅₀ ), the studied drugs induced the production of reactive oxygen species (ROS), suggesting that the oxidative stress may represent a mechanism of ARV toxicity. As assessed by gelatin zymography and RT-PCR, the single antiretroviral drugs reduced levels and expression of both MMP-2 and MMP-9 through the inhibition of the signaling transduction pathway of extracellular signal-regulated kinase1/2, which is involved in the regulation of MMP-9 gene. A synergistic inhibition of MMP-2 and MMP-9 was observed with combinations of the studied ARV drugs. The present results indicate that maraviroc, darunavir, and raltegravir, through their ability to inhibit MMP-2 and MMP-9 at doses non-toxic for astrocytes, might have a great potential for the management of HIV-associated neurological complications.

Quercetin Improves Neurobehavioral Performance Through Restoration of Brain Antioxidant Status and Acetylcholinesterase Activity in Manganese-Treated Rats

The present study investigated the neuroprotective mechanism of quercetin by assessing the biochemical and behavioral characteristics in rats sub-chronically treated with manganese alone at 15 mg/kg body weight or orally co-treated with quercetin at 10 and 20 mg/kg body weight for 45 consecutive days. Locomotor behavior was monitored using video-tracking software during a 10-min trial in a novel environment whereas the brain regions namely the hypothalamus, cerebrum and cerebellum of the rats were processed for biochemical analyses. Results indicated that co-treatment with quercetin significantly (p < 0.05) prevented manganese-induced locomotor and motor deficits specifically the decrease in total distance travelled, total body rotation, maximum speed, absolute turn angle as well as the increase in time of immobility and grooming. The improvement in the neurobehavioral performance of manganese-treated rats following quercetin co-treatment was confirmed by track and occupancy plot analyses. Moreover, quercetin assuaged manganese-induced decrease in antioxidant enzymes activities and the increase in acetylcholinesterase activity, hydrogen peroxide generation and lipid peroxidation levels in the hypothalamus, cerebrum and cerebellum of the rats. Taken together, quercetin mechanisms of ameliorating manganese-induced neurotoxicity is associated with restoration of acetylcholinesterase activity, augmentation of redox status and inhibition of lipid peroxidation in brain of rats.

Manganese neurotoxicity and protective effects of resveratrol and quercetin in preclinical research

BACKGROUND

Exposure to Mn results in a neurological syndrome known as manganism.

METHODS

We examined how 4-week Mn exposure (20mg/kg MnCl₂po, 5days/week) induces neurotoxic effects in rats. Oxidized-to-reduced glutathione ratio (GSSG/GSH), malondialdehyde (MDA), superoxide dismutase (SOD) activity, catalase (CAT) activity, vitamin E content and caspase-3 activity were measured in several rat brain structures. Further, we examined protective effects of the polyphenols: resveratrol (R) or quercetin (QCT) against Mn-induced neurotoxicity.

RESULTS

After exposure to Mn, we found a rise in GSSG/GSH ratio and a reduction in SOD activity in the rat striatum (STR), while in the nucleus accumbens (NAC) decreases in alpha-tocopherol content and in SOD activity were noted. In the frontal cortex (FCX), an enhancement in GSSG/GSH ratio and a reduction in SOD and CAT activities were observed. In the cerebellum (CER), a significant increase in the caspase-3 activity paralleled a rise in the GSSG/GSH ratio and a diminution of SOD activity. In the rat hippocampus (HIP), Mn evoked an enhancement in GSSG/GSH ratio. There were no changes in the MDA levels. Pretreatment with R and QCT protected against the Mn-induced (i) enhancement in GSSG/GSH ratio in the STR, (ii) decreases in the NAC alpha-tocopherol content and (iii) reduction in SOD activity in FCX, NAC and CER.

CONCLUSION

Repeated Mn administration induces toxic effects in several rat brain structures and treatment with R and QCT may be a potential therapeutic strategy to attenuate the metal neurotoxicity.

The Influence of Manganese and Glutamine Intake on Antioxidants and Neurotransmitter Amino Acids Levels in Rats' Brain

Depending on the concentration, Mn can exert protective or toxic effect. Potential mechanism for manganese neurotoxicity is manganese-induced oxidative stress. Glutamine supplementation could reduce manganese-induced neurotoxicity and is able to influence the neurotransmission processes. The aim of this study was to investigate whether the long term administration of manganese (alone or in combination with glutamine) in dose and time dependent manner could affect the selected parameters of oxidative-antioxidative status (superoxide dismutase and glutathione peroxidase activities, concentrations of vitamin C and malonic dialdehyde) and concentrations of excitatory (Asp, Glu) and inhibitory amino acids (GABA, Gly) in the brain of rats. The experiments were carried out on 2-months-old albino male rats randomly divided into 6 group: Mn300 and Mn500—received solution of MnCl₂ to drink (dose 300 and 500 mg/L, respectively), Gln group—solution of glutamine (4 g/L), Mn300-Gln and Mn500-Gln groups—solution of Mn at 300 and 500 mg/L and Gln at 4 g/L dose. The control group (C) received deionized water. Half of the animals were euthanized after three and the other half—after 6 weeks of experiment. The exposure of rats to Mn in drinking water contributes to diminishing of the antioxidant enzymes activity and the increase in level of lipid peroxidation. Glutamine in the diet admittedly increases SOD and GPx activity, but it is unable to restore the intracellular redox balance. The most significant differences in the examined amino acids levels in comparison to both control and Gln group were observed in the group of rats receiving Mn at 500 mg/L dose alone or with Gln. It seems that Gln is amino acid which could improve antioxidant status and affect the concentrations of the neurotransmitters.

Cytotoxicity Study on Luminescent Nanocrystals Containing Phospholipid Micelles in Primary Cultures of Rat Astrocytes

Luminescent colloidal nanocrystals (NCs) are emerging as a new tool in neuroscience field, representing superior optical probes for cellular imaging and medical diagnosis of neurological disorders with respect to organic fluorophores. However, only a limited number of studies have, so far, explored NC applications in primary neurons, glia and related cells. Indeed astrocytes, as resident cells in the central nervous system (CNS), play an important pathogenic role in several neurodegenerative and neuroinflammatory diseases, therefore enhanced imaging tools for their thorough investigation are strongly amenable. Here, a comprehensive and systematic study on the in vitro toxicological effect of core-shell type luminescent CdSe@ZnS NCs incorporated in polyethylene glycol (PEG) terminated phospholipid micelles on primary cultures of rat astrocytes was carried out. Cytotoxicity response of empty micelles based on PEG modified phospholipids was compared to that of their NC containing counterpart, in order to investigate the effect on cell viability of both inorganic NCs and micelles protecting NC surface. Furthermore, since the surface charge and chemistry influence cell interaction and toxicity, effect of two different functional groups terminating PEG-modified phospholipid micelles, namely amine and carboxyl group, respectively, was evaluated against bare micelles, showing that carboxyl group was less toxic. The ability of PEG-lipid micelles to be internalized into the cells was qualitatively and quantitatively assessed by fluorescence microscopy and photoluminescence (PL) assay. The results of the experiments clearly demonstrate that, once incorporated into the micelles, a low, not toxic, concentration of NCs is sufficient to be distinctly detected within cells. The overall study provides essential indications to define the optimal experimental conditions to effectively and profitably use the proposed luminescent colloidal NCs as optical probe for future in vivo experiments.

Recombinant Arabidopsis HSP70 Sustains Cell Survival and Metastatic Potential of Breast Cancer Cells

The chaperone HSP70 protein is widely present in many different tumors and its expression correlates with an increased cell survival, low differentiation, and poor therapeutic outcome in human breast cancer. The intracellular protein has prevalently a cytoprotective function, while the extracellular HSP70 mediates immunologic responses. Evolutionarily, HSPs are well conserved from prokaryotes to eukaryotes, and human HSP70 shows a strong similarity to that of plant origin. In the current article, we have tested the potential effect of recombinant HSP70, from Arabidopsis thaliana, on cell survival and metastatic properties of breast cancer cells. Our data show that HSP70 sustains cell viability in MCF-7 and MDA-MB-231 breast tumoral cells and increases Cyclin D1 and Survivin expression. The extracellular HSP70 triggers cell migration and the activation of MMPs particularly in MDA-MB-231 cells. Furthermore, under UV-induced stress condition, the low levels of phospho-AKT were increased by exogenous HSP70, together with the upregulation of Cyclin D1, particularly in the tumoral cell phenotype. On the other hand, UV increased TP53 expression, and the coincubation of HSP70 lowers the TP53 levels similar to the control. These findings correlate with the cytoprotective and antiapoptotic role of HSPs, as reported in different cellular contexts. This is the first study on mammary cells that highlights how the heterologous HSP70 from Arabidopsis thaliana sustains cell survival prevalently in breast cancer cell types, thus maintaining their metastatic potential. Therefore, targeting HSP70 would be of clinical importance since HSP70 blocking selectively targets tumor cells, in which it supports cell growth and survival. Mol Cancer Ther; 15(5); 1063-73. ©2016 AACR.

Anti-inflammatory nutritional intervention in patients with relapsing-remitting and primary-progressive multiple sclerosis: A pilot study

The aim of this work was to assess the influence of nutritional intervention on inflammatory status and wellness in people with multiple sclerosis. To this end, in a seven-month pilot study we investigated the effects of a calorie-restricted, semi-vegetarian diet and administration of vitamin D and other dietary supplements (fish oil, lipoic acid, omega-3 polyunsaturated fatty acids, resveratrol and multivitamin complex) in 33 patients with relapsing-remitting multiple sclerosis and 10 patients with primary-progressive multiple sclerosis. At 0/3/6 months, patients had neurological examination, filled questionnaires and underwent anthropometric measurements and biochemical analyses. Serum fatty acids and vitamin D levels were measured as markers of dietary compliance and nutritional efficacy of treatment, whereas serum gelatinase levels were analyzed as markers of inflammatory status. All patients had insufficient levels of vitamin D at baseline, but their values did not ameliorate following a weekly administration of 5000  IU, and rather decreased over time. Conversely, omega-3 polyunsaturated fatty acids increased already after three months, even under dietary restriction only. Co-treatment with interferon-beta in relapsing-remitting multiple sclerosis was irrelevant to vitamin D levels. After six months nutritional treatment, no significant changes in neurological signs were observed in any group. However, serum levels of the activated isoforms of gelatinase matrix metalloproteinase-9 decreased by 59% in primary-progressive multiple sclerosis and by 51% in relapsing-remitting multiple sclerosis patients under nutritional intervention, including dietary supplements. This study indicates that a healthy nutritional intervention is well accepted by people with multiple sclerosis and may ameliorate their physical and inflammatory status.

Inhibitory Effect of Aqueous Extracts from Marine Sponges on the Activity and Expression of Gelatinases A (MMP-2) and B (MMP-9) in Rat Astrocyte Cultures

The aim of this study was to evaluate whether water soluble compounds present in aqueous extracts from seven Mediterranean demosponges exert biological activity towards matrix metalloproteinases (MMPs), which represent important pathogenic factors of human diseases. Aqueous extracts were tested on LPS-activated cultured rat astrocytes, and levels and expression of MMP-2 and MMP-9 were assessed by zymography and RT-PCR, respectively. Our results demonstrated that the studied extracts contain water soluble compounds able to inhibit MMP-2 and MMP-9 activity and expression. We also compared the anti-MMP activities present in aqueous extracts from wild and reared specimens of Tethya aurantium and T. citrina. The results obtained revealed that the reared sponges maintain the production of bioactive compounds with inhibitory effect on MMP-2 and MMP-9 for all the duration of the rearing period. Taken together, our results indicate that the aqueous extracts from the selected Mediterranean demosponges possess a variety of water-soluble bioactive compounds, which are able to inhibit MMPs at different levels. The presence of biological activity in aqueous extracts from reared specimens of T. aurantium and T. citrina strongly encourage sponge aquaculture as a valid option to supply sponge biomass for drug development on a large scale.

N-acetylcysteineamide protects against manganese-induced toxicity in SHSY5Y cell line

Manganese (Mn) is an essential trace element required for normal cellular functioning. However, overexposure of Mn can be neurotoxic resulting in the development of manganism, a syndrome that resembles Parkinson׳s disease. Although the pathogenetic basis of this disorder is unclear, several studies indicate that it is mainly associated with oxidative stress and mitochondrial energy failure. Therefore, this study is focused on (1) investigating the oxidative effects of Mn on neuroblastoma cells (SHSY5Y) and (2) elucidating whether a novel thiol antioxidant, N-acetylcysteineamide (NACA), provides any protection against Mn-induced neurotoxicity. Reactive oxygen species (ROS) were highly elevated after the exposure, indicating that mechanisms that induce oxidative stress were involved. Measures of oxidative stress parameters, such as glutathione (GSH), malondialdehyde (MDA), and activities of glutathione reductase (GR) and glutathione peroxidase (GPx) were altered in the Mn-treated groups. Loss of mitochondrial membrane potential, as assessed by flow cytometry and decreased levels of ATP, indicated that cytotoxicity was mediated through mitochondrial dysfunction. However, pretreatment with NACA protected against Mn-induced toxicity by inhibiting lipid peroxidation, scavenging ROS, and preserving intracellular GSH and mitochondrial membrane potential. NACA can potentially be developed into a promising therapeutic option for Mn-induced neurotoxicity. This article is part of a Special Issue entitled SI: Metals in neurodegeneration.

Nutrition facts in multiple sclerosis

The question whether dietary habits and lifestyle have influence on the course of multiple sclerosis (MS) is still a matter of debate, and at present, MS therapy is not associated with any information on diet and lifestyle. Here we show that dietary factors and lifestyle may exacerbate or ameliorate MS symptoms by modulating the inflammatory status of the disease both in relapsing-remitting MS and in primary-progressive MS. This is achieved by controlling both the metabolic and inflammatory pathways in the human cell and the composition of commensal gut microbiota. What increases inflammation are hypercaloric Western-style diets, characterized by high salt, animal fat, red meat, sugar-sweetened drinks, fried food, low fiber, and lack of physical exercise. The persistence of this type of diet upregulates the metabolism of human cells toward biosynthetic pathways including those of proinflammatory molecules and also leads to a dysbiotic gut microbiota, alteration of intestinal immunity, and low-grade systemic inflammation. Conversely, exercise and low-calorie diets based on the assumption of vegetables, fruit, legumes, fish, prebiotics, and probiotics act on nuclear receptors and enzymes that upregulate oxidative metabolism, downregulate the synthesis of proinflammatory molecules, and restore or maintain a healthy symbiotic gut microbiota. Now that we know the molecular mechanisms by which dietary factors and exercise affect the inflammatory status in MS, we can expect that a nutritional intervention with anti-inflammatory food and dietary supplements can alleviate possible side effects of immune-modulatory drugs and the symptoms of chronic fatigue syndrome and thus favor patient wellness.

Resveratrol down-regulates a glutamate-induced tissue plasminogen activator via Erk and AMPK/mTOR pathways in rat primary cortical neurons

Resveratrol (3,5,4'-trihydroxy-trans-stilbene, RSV) is a polyphenolic compound present in a variety of plant species (including grapes) that produces a myriad of biological activities including anti-inflammatory, antioxidant and neuroprotective effects. In this study, we investigate the effects of resveratrol on the basal and glutamate-stimulated expression and activity of a tissue plasminogen activator (tPA) that plays neuromodulatory or neurotoxic roles in many different neurological situations. Under basal conditions, resveratrol decreased the tPA expression and activity without affecting the tPA mRNA level in rat primary cortical neurons. RSV induced AMPK phosphorylation and inhibited mTOR phosphorylation. Inhibition of AMPK phosphorylation using compound C prevented resveratrol-induced down-regulation of tPA activity. This suggested that AMPK/mTOR-dependent translational inhibition contributes to the down-regulation of the tPA. Under glutamate-stimulated conditions of rat primary cortical neurons, tPA activity and expression were increased along with increased tPA mRNA expression but afterward treatment of RSV inhibited the glutamate-induced increase in tPA activity and expression and tPA mRNA expression. Glutamate stimulation induced activation of Akt and MAPK pathways as well as mTOR which were inhibited by RSV. Interestingly, the Erk pathway inhibitor U0126, but neither PI3K-Akt inhibitor LY294002 nor p38 inhibitor SB203580, mimicked the inhibitory action of RSV on glutamate-induced tPA up-regulation. This suggested the essential role of Erk in the transcriptional up-regulation of tPA expression, which is targeted by RSV. Glutamate stimulation induced neuronal cell death as determined by PI staining and MTT assay. However, RSV protected the cultured rat primary cortical neurons from glutamate-induced cell death as paralleled with the changes in tPA expression. These results suggested that RSV can modulate tPA activity under basal and stimulated conditions by both translational and transcriptional mechanisms. The regulation of the tPA by RSV provides additional therapeutic targets on top of the growing number of molecular substrates of RSV's action in the brain.

Comparative analysis of protein profiles of aqueous extracts from marine sponges and assessment of cytotoxicity on different mammalian cell types

Marine natural products extracted from sponges represent a new source for drug discovery. Here we describe a simple method for preparing aqueous extracts from 7 Mediterranean demosponges, which allowed the extraction of water-soluble compounds, such as proteins by homogenization of sponge tissue in phosphate buffered saline (PBS). The comparative analysis by SDS-PAGE showed differences in number of bands, bandwidth and intensity among the sponges analyzed. The PAS/silver staining revealed a substantial and different glycoprotein assortment among the demosponges studied. To further study the biological activities present in the sponge extracts, we determined the non-cytotoxic doses on four different mammalian cell types demonstrating that the optimal non-cytotoxic doses were cell type- and extract-dependent. In conclusion, the extraction method described in this paper represents a fast and efficient procedure for the extraction of water-soluble proteins from marine sponges. Furthermore, the cell viability data suggest the feasibility of this method for the direct in vitro cell-based assays.