A high fat diet potentiates neonatal iron overload-induced memory impairments in rats.

PURPOSE: The present study aimed at evaluating possible synergistic effects between two risk factors for cognitive decline and neurodegenerative disorders, i.e. iron overload and exposure to a hypercaloric/hyperlipidic diet, on cognition, insulin resistance, and hippocampal GLUT1, GLUT3, Insr mRNA expression, and AKT phosporylation. METHODS: Male Wistar rats were treated with iron (30 mg/kg carbonyl iron) or vehicle (5% sorbitol in water) from 12 to 14th post-natal days. Iron-treated rats received a standard laboratory diet or a high fat diet from weaning to adulthood (9 months of age). Recognition and emotional memory, peripheral blood glucose and insulin levels were evaluated. Glucose transporters (GLUT 1 and GLUT3) and insulin signaling were analyzed in the hippocampus of rats. RESULTS: Both iron overload and exposure to a high fat diet induced memory deficits. Remarkably, the association of iron with the high fat diet induced more severe cognitive deficits. Iron overload in the neonatal period induced higher insulin levels associated with significantly higher HOMA-IR, an index of insulin resistance. Long-term exposure to a high fat diet resulted in higher fasting glucose levels. Iron treatment induced changes in Insr and GLUT1 expression in the hippocampus. At the level of intracellular signaling, both iron treatment and the high fat diet decreased AKT phosphorylation. CONCLUSION: The combination of iron overload with exposure to a high fat diet only led to synergistic deleterious effect on emotional memory, while the effects induced by iron and by the high fat diet on AKT phosphorylation were comparable. These findings indicate that there is, at least to some extent, an additive effect of iron combined with the diet. Further studies investigating the mechanisms associated to deleterious effects on cognition and susceptibility for the development of age-associated neurodegenerative disorders are warranted.

Inhibition of ATP hydrolysis as a key regulator of temozolomide resistance and migratory phenotype of glioblastoma cells.

Glioblastoma (GBM) is the most lethal among malignant gliomas. The tumor invasiveness and therapy-resistance are important clinical hallmarks. Growing evidence emphasizes the purinergic signaling contributing to tumor growth. Here we exposed a potential role of extracellular ATPase activity as a key regulator of temozolomide cytotoxicity and the migration process in GBM cells. The inhibition of ATP hydrolysis was able to improve the impact of temozolomide, causing arrest mainly in S and G2 phases of the cell cycle, leading M059J and U251 cells to apoptosis. In addition to eradicating GBM cells, ATP hydrolysis exhibited a potential to modulate the invasive phenotype and the expression of proteins involved in cell migration and epithelial-to-mesenchymal-like transition in a 3D culture model. Finally, we suggest the ATPase activity as a key target to decline temozolomide resistance and the migratory phenotype in GBM cells.

P2Y12 receptor antagonism inhibits proliferation, migration and leads to autophagy of glioblastoma cells.

Glioblastoma (GBM) is the most aggressive and lethal among the primary brain tumors, with a low survival rate and resistance to radio and chemotherapy. The P2Y12 is an adenosine diphosphate (ADP) purinergic chemoreceptor, found mainly in platelets. In cancer cells, its activation has been described to induce proliferation and metastasis. Bearing in mind the need to find new treatments for GBM, this study aimed to investigate the role of the P2Y12R in the proliferation and migration of GBM cells, as well as to evaluate the expression of this receptor in patients' data obtained from the TCGA data bank. Here, we used the P2Y12R antagonist, ticagrelor, which belongs to the antiplatelet agent's class. The different GBM cells (cell line and patient-derived cells) were treated with ticagrelor, with the agonist, ADP, or both, and the effects on cell proliferation, colony formation, ADP hydrolysis, cell cycle and death, migration, and cell adhesion were analyzed. The results showed that ticagrelor decreased the viability and the proliferation of GBM cells. P2Y12R antagonism also reduced colony formation and migration potentials, with alterations on the expression of metalloproteinases, and induced autophagy in GBM cells. Changes were observed at the cell cycle level, and only the U251 cell line showed a significant reduction in the ADP hydrolysis profile. TCGA data analysis showed a higher expression of P2Y12R in gliomas samples when compared to the other tumors. These data demonstrate the importance of the P2Y12 receptor in gliomas development and reinforce its potential as a pharmacological target for glioma treatment.

Effects of lipoic acid supplementation on age- and iron-induced memory impairment, mitochondrial DNA damage and antioxidant responses.

PURPOSE: To investigate the effects of lipoic acid (LA) supplementation during adulthood combined with supplementation later in life or LA administration only at old age on age-induced cognitive dysfunction, mitochondrial DNA deletions, caspase 3 and antioxidant response enzymes expression in iron-treated rats. METHODS: Male rats were submitted to iron treatment (30 mg/kg body wt of Carbonyl iron) from 12 to 14th post-natal days. Iron-treated rats received LA supplementation (50 mg/kg, daily) in adulthood and old age or at old age only for 21 days. Memory, mitochondrial DNA (mtDNA) complex I deletions, caspase 3 mRNA expression and antioxidant response enzymes mRNA expression were analyzed in the hippocampus. RESULTS: LA administration in adulthood combined with treatment later in life was able to reverse age-induced effects on object recognition and inhibitory avoidance memory, as well as on mtDNA deletions, nuclear factor (erythroid-derived 2)-like 2 (Nrf2) expression, and antioxidant enzymes disruption induced by iron in aged rats. LA treatment only at old age reversed iron-induced effects to a lesser extent when compared to the combined treatment. CONCLUSION: The present findings support the view that LA supplementation may be considered as an adjuvant against mitochondrial damage and cognitive decline related to aging and neurodegenerative disorders.

Co-exposure to nTiO2 impairs arsenic metabolism and affects antioxidant capacity in the marine shrimp Litopenaeus vannamei.

Aquatic animals are vulnerable to arsenic (As) toxicity. However, rarely does a contaminant occur alone in the aquatic environment. For this reason, this study was conducted to evaluate whether titanium dioxide nanoparticles (nTiO2) can interfere with the effects induced by As in Litopenaeus vannamei. Arsenic accumulation and metabolic capacity; expression and enzymatic activity of GSTΩ (glutathione-S-transferase omega isoform); antioxidant responses such as GSH, GR, and GST (reduced glutathione levels, glutathione reductase, and glutathione-S-transferase activity, respectively); and lipid peroxidation in the gills and hepatopancreas of shrimp were evaluated. The results are summarized as follows: (1) higher accumulation of As occurred in both tissues after exposure to As alone; (2) co-exposure to nTiO2 affected the capacity to metabolize As; (3) GSTΩ gene expression was not modified, but its activity was decreased by co-exposure to both contaminants; (4) As alone increased the GSH levels in the hepatopancreas, and co-exposure to nTiO2 reduced these levels in both tissues; (5) a decrease in the GST activity in the gills occurred with all treatments; (6) in the gills, GR activity was increased by As, and nTiO2 reversed this increase, whereas in the hepatopancreas co-exposure inhibited enzyme activity; (7) only in the hepatopancreas lipid damage was observed when animals were exposed to As or nTiO2 but not in co-exposure. The results showed that the As induces toxic effects in both tissues of shrimp and that co-exposure to nTiO2 can potentiate these effects and decrease the capacity to metabolize As, favoring the accumulation of more toxic compounds.

Iron chelator deferiprone rescues memory deficits, hippocampal BDNF levels and antioxidant defenses in an experimental model of memory impairment.

Brain-derived neurotrophic factor (BDNF) plays a key role in neural development and physiology, as well as in pathological states. Post-mortem studies demonstrate that BDNF is reduced in the brains of patients affected by neurodegenerative diseases. Iron accumulation has also been associated to the pathogenesis of neurodegenerative diseases. In rats, iron overload induces persistent memory deficits, increases oxidative stress and apoptotic markers, and decreases the expression of the synaptic marker, synaptophysin. Deferiprone (DFP) is an oral iron chelator used for the treatment of systemic iron overload disorders, and has recently been tested for Parkinson's disease. Here, we investigated the effects of iron overload on BDNF levels and on mRNA expression of genes encoding TrkB, p75NTR, catalase (CAT) and NQO1. We also aimed at investigating the effects of DFP on iron-induced impairments. Rats received iron or vehicle at postnatal days 12-14 and when adults, received chronic DFP or water (vehicle). Recognition memory was tested 19 days after the beginning of chelation therapy. BDNF measurements and expression analyses in the hippocampus were performed 24 h after the last day of DFP treatment. DFP restored memory and increased hippocampal BDNF levels, ameliorating iron-induced effects. Iron overload in the neonatal period reduced, while treatment with DFP was able to rescue, the expression of antioxidant enzymes CAT and NQO1.

Hyperglycemia alters E-NTPDases, ecto-5'-nucleotidase, and ectosolic and cytosolic adenosine deaminase activities and expression from encephala of adult zebrafish (Danio rerio).

Hyperglycemia is the main feature for the diagnosis of diabetes mellitus (DM). Some studies have demonstrated the relationship between DM and dysfunction on neurotransmission systems, such as the purinergic system. In this study, we evaluated the extracellular nucleotide hydrolysis and adenosine deamination activities from encephalic membranes of hyperglycemic zebrafish. A significant decrease in ATP, ADP, and AMP hydrolyses was observed at 111-mM glucose-treated group, which returned to normal levels after 7 days of glucose withdrawal. A significant increase in ecto-adenosine deaminase activity was observed in 111-mM glucose group, which remain elevated after 7 days of glucose withdrawal. The soluble-adenosine deaminase activity was significantly increased just after 7 days of glucose withdrawal. We also evaluated the gene expressions of ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDases), ecto-5'-nucleotidase, ADA, and adenosine receptors from encephala of adult zebrafish. The entpd 2a.1, entpd 2a.2, entpd 3, and entpd 8 mRNA levels from encephala of adult zebrafish were decreased in 111-mM glucose-treated and glucose withdrawal groups. The gene expressions of adenosine receptors (adora 1 , adora 2aa , adora 2ab , and adora 2b ) were decreased in 111-mM glucose-treated and glucose withdrawal groups. The gene expression of ADA (ada 2a.1) was decreased in glucose withdrawal group. Maltodextrin, used as a control, did not affect the expression of adenosine receptors, ADA and E-NTPDases 2, 3, and 8, while the expression of ecto-5'-nucleotidase was slightly increased and the E-NTPDases 1 decreased. These findings demonstrated that hyperglycemia might affect the ecto-nucleotidase and adenosine deaminase activities and gene expression in zebrafish, probably through a mechanism involving the osmotic effect, suggesting that the modifications caused on purinergic system may also contribute to the diabetes-induced progressive cognitive impairment.

Benzodiazepines alter nucleotide and nucleoside hydrolysis in zebrafish (Danio rerio) brain.

Anxiety is characterized by unpleasant bodily sensations, such as pounding heart and intense fear. The therapy involves the administration of benzodiazepine drugs. Purinergic signaling participates in the induction of several behavioral patterns and their actions are inactivated by ectonucleotidases and adenosine deaminase (ADA). Since there is evidence about the involvement of purinergic system in the actions mediated by benzodiazepines, we evaluated the effects in vitro and in vivo of administration of diazepam and midazolam on nucleoside triphosphate diphosphohydrolases, ecto-5'-nucleotidase, and ADA activities in zebrafish brain, followed by the analysis of gene expression pattern of these enzymes and adenosine receptors (A1, A2a1, A2a2, A2b). The in vitro studies demonstrated that diazepam decreased ATP (66 % for 500 µM) and ADP hydrolysis (40-54 % for 10-500 µM, respectively). Midazolam decreased ATP (16-71 % for 10-500 µM, respectively) and ADP (48-73.5 % for 250-500 µM, respectively) hydrolysis as well as the ecto-ADA activity (26-27.5 % for 10-500 µM, respectively). AMP hydrolysis was decreased in animals treated with of 0.5 and 1 mg/L midazolam (32 and 36 %, respectively). Diazepam and midazolam decreased the ecto-ADA activity at 1.25 mg/L and 1 mg/L (31 and 33 %, respectively), but only 0.1 mg/L midazolam induced an increase (40 %) in cytosolic ADA. The gene expression analysis demonstrated changes on ecto-5'-nucleotidase, A1, A2a1, A2a2, and A2b mRNA transcript levels after acute treatment with benzodiazepines. These findings demonstrated that benzodiazepine exposure induces a modulation of extracellular nucleotide and nucleoside metabolism, suggesting the purinergic signaling may be, at least in part, related to benzodiazepine effects.

Iron from haemoglobin and haemin modulates nucleotide hydrolysis in Trichomonas vaginalis.

Extracellular ATP may act as a danger signalling molecule, inducing inflammation and immune responses in infection sites. The ectonucleotidases NTPDase and ecto-5'-nucleotidase are enzymes that modulate extracellular nucleotide levels; these enzymes have been previously characterised in Trichomonas vaginalis. Iron plays an important role in the complex trichomonal pathogenesis. Herein, the effects of iron on growth, nucleotide hydrolysis and NTPDase gene expression in T. vaginalis isolates from female and male patients were evaluated. Iron from different sources sustained T. vaginalis growth. Importantly, iron from haemoglobin (HB) and haemin (HM) enhanced NTPDase activity in isolates from female patients and conversely reduced the enzyme activity in isolates from male patients. Iron treatments could not alter the NTPDase transcript levels in T. vaginalis. Furthermore, our results reveal a distinct ATP, ADP and AMP hydrolysis profile between isolates from female and male patients influenced by iron from HB and HM. Our data indicate the participation of NTPDase and ecto-5'-nucleotidase in the establishment of trichomonas infection through ATP degradation and adenosine production influenced by iron.

New insights on the Golgi complex of Tritrichomonas foetus.

Tritrichomonas foetus is a protist that causes bovine trichomoniasis and presents a well-developed Golgi. There are very few studies concerning the Golgi in trichomonads. In this work, monoclonal antibodies were raised against Golgi of T. foetus and used as a tool on morphologic and biochemical studies of this organelle. Among the antibodies produced, one was named mAb anti-Golgi 20.3, which recognized specifically the Golgi complex by fluorescence and electron microscopy. By immunoblotting this antibody recognized two proteins with 60 and 66 kDa that were identified as putative beta-tubulin and adenosine triphosphatase, respectively. The mAb 20.3 also recognized the Golgi complex of the Trichomonas vaginalis, a human parasite. In addition, the nucleotide coding sequences of these proteins were identified and included in the T. foetus database, and the 3D structure of the proteins was predicted. In conclusion, this study indicated: (1) adenosine triphosphatase is present in the Golgi, (2) ATPase is conserved between T. foetus and T. vaginalis, (3) there is new information concerning the nucleic acid sequences and protein structures of adenosine triphosphatase and beta-tubulin from T. foetus and (4) the mAb anti-Golgi 20.3 is a good Golgi marker and can be used in future studies.

Locomotor Behavior and Memory Dysfunction Induced by 3-Nitropropionic Acid in Adult Zebrafish: Modulation of Dopaminergic Signaling.

Huntington's disease (HD) is a progressive neurodegenerative disease characterized by neuropsychiatric disturbance, cognitive impairment, and locomotor dysfunction. In the early stage (chorea) of HD, expression of dopamine D2 receptors (D2R) is reduced, whereas dopamine (DA) levels are increased. Contrary, in the late stage (bradykinesia), DA levels and the expression of D2R and dopamine D1 receptors (D1R) are reduced. 3-Nitropropionic acid (3-NPA) is a toxin that may replicate HD behavioral phenotypes and biochemical aspects. This study assessed the neurotransmitter levels, dopamine receptor gene expression, and the effect of acute exposure to quinpirole (D2R agonist) and eticlopride (D2R antagonist) in an HD model induced by 3-NPA in adult zebrafish. Quinpirole and eticlopride were acutely applied by i.p. injection in adult zebrafish after chronic treatment of 3-NPA (60 mg/kg). 3-NPA treatment caused a reduction in DA, glutamate, and serotonin levels. Quinpirole reversed the bradykinesia and memory loss induced by 3-NPA. Together, these data showed that 3-NPA acts on the dopaminergic system and causes biochemical alterations similar to late-stage HD. These data reinforce the hypothesis that DA levels are linked with locomotor and memory deficits. Thus, these findings may suggest that the use of DA agonists could be a pharmacological strategy to improve the bradykinesia and memory deficits in the late-stage HD.

Toxic effects of environmental-relevant exposure to polyethylene terephthalate (PET) micro and nanoparticles in zebrafish early development.

Polyethylene terephthalate (PET) is a commonly used thermoplastic in industry due to its excellent malleability and thermal stability, making it extensively employed in packaging manufacturing. Inadequate disposal of PET packaging in the environment and natural physical-chemical processes leads to the formation of smaller particles known as PET micro and nanoplastics (MNPs). The reduced dimensions enhance particle bioavailability and, subsequently, their reactivity. This study involved chemical degradation of PET using trifluoroacetic acid to assess the impact of exposure to varying concentrations of PET MNPs (0.5, 1, 5, 10, and 20 mg/L) on morphological, functional, behavioral, and biochemical parameters during the early developmental stages of zebrafish (Danio rerio). Characterization of the degraded PET revealed the generated microplastics (MPs) ranged in size from 1305 to 2032 µm, and that the generated nanoplastics (NPs) ranged from 68.06 to 955 nm. These particles were then used for animal exposure. After a six-day exposure period, our findings indicate that PET MNPs can diminish spontaneous tail coiling (STC), elevate the heart rate, accumulate on the chorion surface, and reduce interocular distance. These results suggest that PET exposure induces primary toxic effects on zebrafish embryo-larval stage of development.

Reduction of Na+, K+-ATPase activity and expression in cerebral cortex of glutaryl-CoA dehydrogenase deficient mice: a possible mechanism for brain injury in glutaric aciduria type I.

Mitochondrial dysfunction has been proposed to play an important role in the neuropathology of glutaric acidemia type I (GA I). However, the relevance of bioenergetics disruption and the exact mechanisms responsible for the cortical leukodystrophy and the striatum degeneration presented by GA I patients are not yet fully understood. Therefore, in the present work we measured the respiratory chain complexes activities I-IV, mitochondrial respiratory parameters state 3, state 4, the respiratory control ratio and dinitrophenol (DNP)-stimulated respiration (uncoupled state), as well as the activities of α-ketoglutarate dehydrogenase (α-KGDH), creatine kinase (CK) and Na+, K+-ATPase in cerebral cortex, striatum and hippocampus from 30-day-old Gcdh-/- and wild type (WT) mice fed with a normal or a high Lys (4.7%) diet. When a baseline (0.9% Lys) diet was given, we verified mild alterations of the activities of some respiratory chain complexes in cerebral cortex and hippocampus, but not in striatum from Gcdh-/- mice as compared to WT animals. Furthermore, the mitochondrial respiratory parameters and the activities of α-KGDH and CK were not modified in all brain structures from Gcdh-/- mice. In contrast, we found a significant reduction of Na(+), K(+)-ATPase activity associated with a lower degree of its expression in cerebral cortex from Gcdh-/- mice. Furthermore, a high Lys (4.7%) diet did not accentuate the biochemical alterations observed in Gcdh-/- mice fed with a normal diet. Since Na(+), K(+)-ATPase activity is required for cell volume regulation and to maintain the membrane potential necessary for a normal neurotransmission, it is presumed that reduction of this enzyme activity may represent a potential underlying mechanism involved in the brain swelling and cortical abnormalities (cortical atrophy with leukodystrophy) observed in patients affected by GA I.

Modulation of adenosine signaling reverses 3-nitropropionic acid-induced bradykinesia and memory impairment in adult zebrafish.

Huntington's disease (HD) is a neurodegenerative disorder, characterized by motor dysfunction, psychiatric disturbance, and cognitive decline. In the early stage of HD, occurs a decrease in dopamine D2 receptors and adenosine A2A receptors (A2AR), while in the late stage also occurs a decrease in dopamine D1 receptors and adenosine A1 receptors (A1R). Adenosine exhibits neuromodulatory and neuroprotective effects in the brain and is involved in motor control and memory function. 3-Nitropropionic acid (3-NPA), a toxin derived from plants and fungi, may reproduce HD behavioral phenotypes and biochemical characteristics. This study investigated the effects of acute exposure to CPA (A1R agonist), CGS 21680 (A2AR agonist), caffeine (non-selective of A1R and A2AR antagonist), ZM 241385 (A2AR antagonist), DPCPX (A1R antagonist), dipyridamole (inhibitor of nucleoside transporters) and EHNA (inhibitor of adenosine deaminase) in an HD pharmacological model induced by 3-NPA in adult zebrafish. CPA, CGS 21680, caffeine, ZM 241385, DPCPX, dipyridamole, and EHNA were acutely administered via i.p. in zebrafish after 3-NPA (at dose 60 mg/kg) chronic treatment. Caffeine and ZM 241385 reversed the bradykinesia induced by 3-NPA, while CGS 21680 potentiated the bradykinesia caused by 3-NPA. Moreover, CPA, caffeine, ZM 241385, DPCPX, dipyridamole, and EHNA reversed the 3-NPA-induced memory impairment. Together, these data support the hypothesis that A2AR antagonists have an essential role in modulating locomotor function, whereas the activation of A1R and blockade of A2AR and A1R and modulation of adenosine levels may reduce the memory impairment, which could be a potential pharmacological strategy against late-stage symptoms HD.

Pyriproxyfen Exposure Impairs Cognitive Parameters and Alters Cortisol Levels in Zebrafish.

Pyriproxyfen is one of the most used larvicides and insecticides; it acts as an analog of juvenile insect hormone (a growth regulator). It is highly toxic during all stages of mosquito development, suppresses metamorphosis, and interferes in insect reproduction and proliferation. Pyriproxyfen and its main metabolite have been shown to affect brain development in rodents. This compound is employed mainly to eliminate outbreaks of the genus Aedes, even in potable water. Despite the increasing number of toxicological studies about larvicides and insecticides-with an indication of continuous use-there have been few studies about the effects of pyriproxyfen in non-target species such as fish. This study evaluated the effects of pyriproxyfen on behavioral, cognitive, and endocrine parameters in zebrafish. We exposed adult zebrafish to different pyriproxyfen (Pestanal®) concentrations (0.125, 0.675, and 1.75 mg/l) for 96 h. We analyzed behavioral parameters, memory, cortisol levels, and gene expression of glucocorticoid receptor (gr) and corticotrophin-releasing factor (crf) after pyriproxyfen exposure. This exposure did not alter locomotion (distance or mean speed), anxiety-like behavior (latency to enter to the top zone of the tank or time in the top zone of the tank), and social or aggressive behavior. However, there was impaired inhibitory avoidance memory at all tested pyriproxyfen concentrations. Cortisol levels were reduced in exposed groups when compared to control or vehicle. However, gr and crf gene expression in pyriproxyfen-treated animals were unaltered when compared to control or vehicle groups. Taken together, these findings indicate that pyriproxyfen may induce cognitive impairment and altered cortisol levels in zebrafish, a non-target species.

Neural Regenerative Potential of Stem Cells Derived from the Tooth Apical Papilla.

The regenerative effects of stem cells derived from dental tissues have been previously investigated. This study assessed the potential of human tooth stem cells from apical papilla (SCAP) on nerve regeneration. The SCAP collected from nine individuals were characterized and polarized by exposure to interferon-γ (IFN-γ). IFN-γ increased kynurenine and interleukin-6 (IL-6) production by SCAP, without affecting the cell viability. IFN-γ-primed SCAP exhibited a decrease of brain-derived neurotrophic factor (BDNF) mRNA levels, followed by an upregulation of glial cell-derived neurotrophic factor mRNA. Ex vivo, the co-culture of SCAP with neurons isolated from the rat dorsal root ganglion induced neurite outgrowth, accompanied by increased BDNF secretion, irrespective of IFN-γ priming. In vivo, the local application of SCAP reduced the mechanical and thermal hypersensitivity in Wistar rats that had been submitted to sciatic chronic constriction injury. The SCAP also reduced the pain scores, according to the evaluation of the Grimace scale, partially restoring the myelin damage and BDNF immunopositivity secondary to nerve lesion. Altogether, our results provide novel evidence about the regenerative effects of human SCAP, indicating their potential to handle nerve injury-related complications.

Graphene oxide and GST-omega enzyme: An interaction that affects arsenic metabolism in the shrimp Litopenaeus vannamei.

Arsenic (As) is one of the most widespread contaminants; it is found in almost every environment. Its toxic effects on living organisms have been studied for decades, but the interaction of this metalloid with other contaminants is still relatively unknown, mainly whether this interaction occurs with emerging contaminants such as nanomaterials. To examine this relationship, the marine shrimp Litopenaeus vannamei was exposed for 48 h to As, graphene oxide (GO; two different concentrations) or a combination of both, and gills, hepatopancreas and muscle tissues were sampled. Glutathione S-transferase (GST)-omega gene expression and activity were assessed. As accumulation and speciation (metabolisation capacity) were also examined. Finally, a molecular docking simulation was performed to verify the possible interaction between the nanomaterial and GST-omega. The main finding was that GO modulated the As toxic effect: it decreased GST-omega activity, a consequence related to altered As accumulation and metabolism. Besides, the molecular docking simulation confirmed the capacity of GO to interact with the enzyme structure, which also can be related to the decreased GST-omega activity and subsequently to the altered As accumulation and metabolisation pattern.

Novel insights into mitochondrial molecular targets of iron-induced neurodegeneration: Reversal by cannabidiol.

Evidence has demonstrated iron accumulation in specific brain regions of patients suffering from neurodegenerative disorders, and this metal has been recognized as a contributing factor for neurodegeneration. Using an experimental model of brain iron accumulation, we have shown that iron induces severe memory deficits that are accompanied by oxidative stress, increased apoptotic markers, and decreased synaptophysin in the hippocampus of rats. The present study aims to characterize iron loading effects as well as to determine the molecular targets of cannabidiol (CBD), the main non-psychomimetic compound of Cannabis sativa, on mitochondria. Rats received iron in the neonatal period and CBD for 14 days in adulthood. Iron induced mitochondrial DNA (mtDNA) deletions, decreased epigenetic modulation of mtDNA, mitochondrial ferritin levels, and succinate dehydrogenase activity. CBD rescued mitochondrial ferritin and epigenetic modulation of mtDNA, and restored succinate dehydrogenase activity in iron-treated rats. These findings provide new insights into molecular targets of iron neurotoxicity and give support for the use of CBD as a disease modifying agent in the treatment of neurodegenerative diseases.

Brain bioenergetics in rats with acute hyperphenylalaninemia.

Phenylketonuria (PKU) is a disorder of phenylalanine (Phe) metabolism caused by deficient phenylalanine hydroxylase (PAH) activity. The deficiency results in increased levels of Phe and its metabolites in fluids and tissues of patients. PKU patients present neurological signs and symptoms including hypomyelination and intellectual deficit. This study assessed brain bioenergetics at 1 h after acute Phe administration to induce hyperphenylalaninemia (HPA) in rats. Wistar rats were randomized in two groups: HPA animals received a single subcutaneous administration of Phe (5.2 µmol/g) plus p-Cl-Phe (PAH inhibitor) (0.9 µmol/g); control animals received a single injection of 0.9% NaCl. In cerebral cortex, HPA group showed lower mitochondrial mass, lower glycogen levels, as well as lower activities of complexes I-III and IV, ATP synthase and citrate synthase. Higher levels of free Pi and phospho-AMPK, and higher activities of LDH, α-ketoglutarate dehydrogenase and isocitrate dehydrogenase were also reported in cerebral cortex of HPA animals. In striatum, HPA animals had higher LDH (pyruvate to lactate) and isocitrate dehydrogenase activities, and lower activities of α-ketoglutarate dehydrogenase and complex IV, as well as lower phospho-AMPK immunocontent. In hippocampus, HPA rats had higher mRNA expression for MFN1 and higher activities of α-ketoglutarate dehydrogenase and isocitrate dehydrogenase, but decreased activities of pyruvate dehydrogenase and complexes I and IV. In conclusion, our data demonstrated impaired bioenergetics in cerebral cortex, striatum and hippocampus of HPA rats.

Effects of caffeine on behavioral and inflammatory changes elicited by copper in zebrafish larvae: Role of adenosine receptors.

This study investigated the effects of caffeine in the behavioral and inflammatory alterations caused by copper in zebrafish larvae, attempting to correlate these changes with the modulation of adenosine receptors. To perform a survival curve, 7dpf larvae were exposed to 10µM CuSO4, combined to different concentrations of caffeine (100µM, 500µM and 1mM) for up to 24h. The treatment with copper showed lower survival rates only when combined with 500µM and 1mM of caffeine. We selected 4 and 24h as treatment time-points. The behavior evaluation was done by analyzing the traveled distance, the number of entries in the center, and the length of permanence in the center and the periphery of the well. The exposure to 10µM CuSO4 plus 500µM caffeine at 4 and 24h changed the behavioral parameters. To study the inflammatory effects of caffeine, we assessed the PGE2 levels by using UHPLC-MS/MS, and TNF, COX-2, IL-6 and IL-10 gene expression by RT-qPCR. The expression of adenosine receptors was also evaluated with RT-qPCR. When combined to copper, caffeine altered inflammatory markers depending on the time of exposure. Adenosine receptors expression was significantly increased, especially after 4h exposure to copper and caffeine together or separately. Our results demonstrated that caffeine enhances the inflammation induced by copper by decreasing animal survival, altering inflammatory markers and promoting behavioral changes in zebrafish larvae. We also conclude that alterations in adenosine receptors are related to those effects.