Publications by authors named "Antônio Carlos Pinheiro de Oliveira"

39 Publications

PI3K, mTOR and GSK3 modulate cytokines' production in peripheral leukocyte in temporal lobe epilepsy.

Neurosci Lett 2021 Jun 9;756:135948. Epub 2021 May 9.

Neuroscience Program, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil; Department of Pharmacology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. Electronic address:

Introduction: Epilepsy is a common pathological condition that predisposes individuals to seizures, as well as cognitive and emotional dysfunctions. Different studies have demonstrated that inflammation contributes to the pathophysiology of epilepsy. Indeed, seizures change the peripheral inflammatory pattern, which, in turn, could contribute to seizures. However, the cause of the altered production of peripheral inflammatory mediators is not known. The PI3K/mTOR/GSK3β pathway is important for different physiological and pharmacological phenomena. Therefore, in the present study, we tested the hypothesis that the PI3K/mTOR/GSK3β pathway is deregulated in immune cells from patients with epilepsy and contributes to the abnormal production of inflammatory mediators.

Methods: Patients with temporal lobe epilepsy presenting hippocampal sclerosis and controls aged between 18 and 65 years-old were selected for this study. Peripheral blood was collected for the isolation of peripheral mononuclear blood cells (PBMC). Cells were pre-incubated with different PI3K, mTOR and GSK-3 inhibitors for 30 min and further stimulated with phytohaemaglutinin (PHA) or vehicle for 24 h. The supernatant was used to evaluate the production of IL-1β, IL-6, IL-10, TNF e IL-12p70.

Results: Non-selective inhibition of PI3K, as well as inhibition of PI3Kγ and GSK-3, reduced the levels of TNF and IL-10 in PHA-stimulated cells from TLE individuals. This stimulus increased the production of IL-12p70 only in cells from TLE individuals, while the inhibition of PI3K and mTOR enhanced the production of this cytokine. On the other hand, inhibition of GSK3 reduced the PHA-induced production of IL-12p70.

Conclusions: Herein we demonstrated that the production of cytokines by immune cells from patients with TLE differs from non-epileptic patients. This differential regulation may be associated with the altered activity and responsiveness of intracellular molecules, such as PI3K, mTOR and GSK-3, which, in turn, might contribute to the inflammatory state that exists in epilepsy and its pathogenesis.
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http://dx.doi.org/10.1016/j.neulet.2021.135948DOI Listing
June 2021

Serotonin and dopamine receptors profile on peripheral immune cells from patients with temporal lobe epilepsy.

J Neuroimmunol 2021 05 5;354:577534. Epub 2021 Mar 5.

Laboratório de Neurofarmacologia, Departamento de Farmacologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil; Programa de Neurociências, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil. Electronic address:

The role of inflammation and immune cells has been demonstrated in neurological diseases, including epilepsy. Leukocytes, as well as inflammatory mediators, contribute to abnormal processes that lead to a reduction in seizure threshold and synaptic reorganization. In this sense, identifying different phenotypes of circulating immune cells is essential to understanding the role of these cells in epilepsy. Immune cells can express a variety of surface markers, including neurotransmitter receptors, such as serotonin and dopamine. Alteration in these receptors expression patterns may affect the level of inflammatory mediators and the pathophysiology of epilepsy. Therefore, in the current study, we evaluated the expression of dopamine and serotonin receptors on white blood cells from patients with temporal lobe epilepsy with hippocampal sclerosis (TLE-HS). Blood samples from 17 patients with TLE-HS and 21 controls were collected. PBMC were isolated and stained ex vivo for flow cytometry. We evaluated the expression of serotonin (5-HT, 5-HT, 5-HT, 5-HT, 5-HT, 5-HT, 5-HT), and dopamine receptors (D, D, D, D, and D) on the cell surface of lymphocytes and innate immune cells (monocytes and granulocytes). Our results demonstrated that innate cells and lymphocytes from patients with TLE-HS showed high mean fluorescent intensity (MFI) for 5-HT, 5-HT, 5-HT and 5-HT compared to controls. No difference was observed for 5-HT. For dopamine receptors, the expression of D, D, D and D receptors was higher on innate cells from patients with TLE-HS when compared to controls for the MFI. Regarding lymphocytes population, D expression was increased in patients with TLE-HS. In conclusion, there are alterations in the expression of serotonin and dopamine receptors on immune blood cells of patients with TLE-HS. Although the biological significance of these findings still needs to be further investigated, these changes may contribute to the understanding of TLE-HS pathophysiology.
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http://dx.doi.org/10.1016/j.jneuroim.2021.577534DOI Listing
May 2021

Evaluation of Brain Cytokines and the Level of Brain-Derived Neurotrophic Factor in an Inflammatory Model of Depression.

Neuroimmunomodulation 2020 11;27(2):87-96. Epub 2020 Nov 11.

Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil,

Introduction: Major depressive disorder is considered a global public health problem. Inflammatory processes are likely involved in its pathophysiology, but the underlying mechanisms have remained uncertain.Here, we used the model of systemic lipopolysaccharide (LPS) injection to test the hypothesis that depressive-like behaviors occur along with changes in the levels of cytokines and brain-derived neurotrophic factor (BDNF) in the hippocampus (HC), prefrontal cortex (PFC), and hypothalamus (HT), and can be prevented by dexamethasone administration.

Methods: Adult C57Bl/6 male mice were first isolated for 10 days, and thereafter received an injection of dexamethasone (6 mg/kg, intraperitoneal [i.p.]), saline followed by LPS (0.83 mg/kg, i.p.), or saline. After 6 h, animals were subjected to the forced-swim test (FST) and open-field tests. Immediately after the behavioral tests, they were euthanized and their brains were collected for the biochemical analyses.

Results: LPS increased the immobility time and reduced the distance travelled in the FST and open-field test, respectively. Dexamethasone increased the immobility time in saline-treated mice but reduced this behavior in the LPS group. LPS increased the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and interferon (IFN)-γ in most of the regions evaluated. Dexamethasone prevented LPS-induced IL-6 in the HC, PFC, and HT. Interestingly, dexamethasone increased IL-4 and IL-10 levels in both the LPS- and saline-treated groups. Although dexamethasone reduced BDNF in saline-treated mice, it prevented LPS-induced reduction in this neurotrophic factor.

Conclusion: In summary, dexamethasone decreased proinflammatory and increased anti-inflammatory levels of cytokines and prevented a reduction in BDNF levels induced by the inflammatory stimulus. Thus, the attenuation of depressive-like behavior induced by dexamethasone may be related to the effects on these parameters.
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http://dx.doi.org/10.1159/000511181DOI Listing
November 2020

A new lipophilic amino alcohol, chemically similar to compound FTY720, attenuates the pathogenesis of experimental autoimmune encephalomyelitis by PI3K/Akt pathway inhibition.

Int Immunopharmacol 2020 Nov 29;88:106919. Epub 2020 Aug 29.

Department of Parasitology, Microbiology and Immunology, Federal University of Juiz de Fora, Juiz de Fora 36036-900, Brazil.

Experimental autoimmune encephalomyelitis (EAE) is one of the main animal models used for the study of Multiple Sclerosis (MS). Long-chain lipophilic amino alcohols with immunoregulatory activities have already been studied in some models of inflammatory diseases, but the action of these compounds in EAE and MS is still unknown. In this study, we investigated whether the lipophilic amino alcohol 4b would act to improve the clinical signs of EAE and reduce the demyelination process and the neuroinflammatory parameters in the spinal cord, as well as the inflammatory process in the inguinal lymph nodes, of C57Bl/6 mice induced with EAE after stimulation with MOG and pertussis toxin. The 4b treatment (1.0 mg/kg/day) was orally administered, starting on the day of onset of clinical signs of the disease (10th) and ending on the 20th day after immunization. This treatment was able to reduce the cell count on the inguinal lymph nodes, the migration of inflammatory cells into the central nervous system (CNS), as well as the processes of microgliosis, astrogliosis, and the production of chemokines and pro-inflammatory cytokines, thus increasing the IL-10 anti-inflammatory cytokine levels in EAE mice. The inhibition of Akt phosphorylation in the CNS of EAE mice after treatment with 4b indicates that the immunoregulatory action of 4b is related to the PI3K/Akt signaling pathway. Our results indicate the immunoregulatory efficacy of the new compound 4b in the control of some inflammatory parameters and in the glial proliferation. In addition, 4b was able to reduce the demyelination of neurons and the worsening of clinical signs of EAE as effectively as the compound FTY720, the first oral drug approved by the FDA for the treatment of MS.
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http://dx.doi.org/10.1016/j.intimp.2020.106919DOI Listing
November 2020

Cannabidiol anticonvulsant effect is mediated by the PI3Kγ pathway.

Neuropharmacology 2020 10 20;176:108156. Epub 2020 Jun 20.

Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil. Electronic address:

The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/Akt)/mechanistic target of rapamycin (mTOR) signaling pathway has been associated with several pathologies in the central nervous system (CNS), including epilepsy. There is evidence supporting the hypothesis that the PI3Kγ signaling pathway may mediate the powerful anticonvulsant properties associated with the cannabinoidergic system. This work aims to investigate if the anticonvulsant and neuroprotective effects of cannabidiol (CBD) are mediated by PI3Kγ. In vitro and in vivo experiments were performed on C57Bl/6 wild-type (WT) and PI3Kγ mice. Behavioral seizures were induced by bilateral intra-hippocampal pilocarpine microinjection. Twenty-four hours after the first behavioral seizure, animals were perfused and their brains removed and processed, for histological analysis of neurodegeneration, microgliosis and astrocytosis. Primary cultures of hippocampal neurons were used for glutamate-induced cell death assay. CDB increased latency and reduced the severity of pilocarpine-induced behavioral seizures, as well as prevented postictal changes, such as neurodegeneration, microgliosis and astrocytosis, in WT animals, but not in PI3Kγ. CBD in vivo effects were abolished by pharmacological inhibition of cannabinoid receptor or mTOR. In vitro, PI3Kγ inhibition or deficiency also changed CBD protection observed in glutamate-induced cell death assay. Thus, we suggest that the modulation of PI3K/mTOR signaling pathway is involved in the anticonvulsant and neuroprotective effects of CBD. These findings are important not only for the elucidation of the mechanisms of action of CBD, which are currently poorly understood, but also to allow the prediction of therapeutic and side effects, ensuring efficacy and safety in the treatment of patients with epilepsy.
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http://dx.doi.org/10.1016/j.neuropharm.2020.108156DOI Listing
October 2020

Neuroprotective Effect of AM404 Against NMDA-Induced Hippocampal Excitotoxicity.

Front Cell Neurosci 2019 20;13:566. Epub 2019 Dec 20.

Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.

Different studies have demonstrated that inflammation and alterations in glutamate neurotransmission are two events contributing to the pathophysiology of neurodegenerative or neurological disorders. There are evidences that N-arachidonoylphenolamine (AM404), a cannabinoid system modulator and paracetamol metabolite, modulates inflammation and exerts neuroprotective effects on Huntington's (HD) and Parkinson's diseases (PD), and ischemia. However, the effects of AM404 on the production of inflammatory mediators and excitotoxicity in brain tissue stimulated with N-methyl-D-aspartic acid (NMDA) are not elucidated. In this present study, we investigated the effects of AM404 on the production of inflammatory mediators and neuronal cell death induced by NMDA in organotypic hippocampal slices cultures (OHSC) using qPCR, western blot (WB), and immunohistochemistry. Moreover, to comprehend the mechanism of excitotoxicity, we evaluated the effects of AM404 on glutamate release in hippocampal synaptosomes and the NMDA-induced calcium responses in acute hippocampal slices. Our results showed that AM404 led to a significant decrease in cell death induced by NMDA, through a mechanism possibly involving the reduction of glutamate release and the calcium ions responses. Furthermore, it decreased the expression of the interleukin (IL)-1β. This study provides new significant insights about the anti-inflammatory and neuroprotection effects of AM404 on NMDA-induced excitotoxicity. To understand the effects of AM404 in these processes might contribute to the therapeutic potential of AM404 in diseases with involvement of neuroinflammation and neurodegeneration and might lead to a possible future treatment of neurodegenerative diseases.
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http://dx.doi.org/10.3389/fncel.2019.00566DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6932953PMC
December 2019

NVP-BEZ235 (Dactolisib) Has Protective Effects in a Transgenic Mouse Model of Alzheimer's Disease.

Front Pharmacol 2019 13;10:1345. Epub 2019 Nov 13.

Department of Pharmacology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.

Alzheimer's disease (AD) is a neurodegenerative disease and the main cause of dementia. Its major symptom is memory loss, which is a result of neuronal cell death, which is accompanied by neuroinflammation. Some studies indicate the overactivation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mechanistic target of rapamycin (mTOR) pathway in this disease, being, thus, a potential target for pharmacological treatment. Here, we used a transgenic mouse model of AD that expresses a mutant amyloid-β precursor protein (T41 mice) to investigate the effects of dactolisib (alternative name: NVP-BEZ235, abbreviation BEZ), a dual PI3K/mTOR inhibitor. Ten-months-old T41 animals were treated for 14 days with BEZ or vehicle oral gavage and then submitted to social memory, open field and contextual conditioned fear tests. Hippocampal slices were prepared and Aβ content, NeuN, Iba-1, CD68 and GFAP were evaluated. Tissues were further processed to evaluate cytokines levels through cytometric bead array. The treatment with BEZ (5 mg/kg) reduced social memory impairment in T41 mice. However, BEZ did not have any effect on altered Aβ levels, NeuN, or GFAP staining. The drug reduced the CD68/Iba-1 ratio in CA3 region of hippocampus. Finally, BEZ diminished IL-10 levels in T41 mice. Thus, although its mechanisms are not clear, BEZ protects against memory impairment, reduces microglial activation and reestablishes IL-10 levels, revealing beneficial effects, which should be further investigated for the treatment of AD.
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http://dx.doi.org/10.3389/fphar.2019.01345DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6864823PMC
November 2019

Minocycline treatment prevents depression and anxiety-like behaviors and promotes neuroprotection after experimental ischemic stroke.

Brain Res Bull 2020 02 19;155:1-10. Epub 2019 Nov 19.

Laboratório de Patologia Celular e Molecular do Departamento de Patologia Geral, Instituto de Ciências Biológicas, UFMG, Brazil; Laboratório Interdisciplinar de Investigação Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, MG, Brazil. Electronic address:

Depression and anxiety have been reported as the major neuropsychiatric consequences following stroke. Minocycline, a neuroprotective drug has minimized depressive symptoms in patients with major depressive disorders and anxiety-like symptoms. In addition, minocycline demonstrated efficacy and seemed a promising neuroprotective agent in acute stroke patients. The present studied evaluated the effects of minocycline treatment on the depression and anxiety-like behaviors, brain damage and expression of inflammatory and neuroprotective mediators after transient global cerebral ischemia in C57BL/6 mice. Brain ischemia was induced by bilateral occlusion of the common carotids (BCCAo) for 25 min and subsequent reperfusion. Sham and BCCAo animals received minocycline at a dose of 30 mg/kg by intraperitoneal injection during 14 days. The locomotor activity, depression and anxiety-like behaviors were assessed by open field, forced swim and elevated plus maze tests, respectively. Then, the brains were removed and processed to evaluate brain damage by histological and morphometric analysis, hippocampal neurodegeneration using Fluoro-Jade C histochemistry, microglial activity using iba-1 immunohistochemistry, brain levels of TNF, IFN-γ, IL-6, IL-10, IL-12p70 and CCL2 by CBA, CX3CL1 and BDNF by ELISA assays. The animals developed depression and anxiety-like behaviors post-stroke and minocycline treatment prevented those neurobehavioral changes. Moreover, minocycline-treated BCCAo animals showed less intense brain damage in the cerebral cortex, brainstem and cerebellum as well as significantly reduced hippocampal neurodegeneration. BCCAo groups exhibited up-regulation of some cytokines at day 14 after ischemia and brain levels of CX3CL1 and BDNF remained unaltered. Our data indicate that the depression and anxiety-like behavioral improvements promoted by minocycline treatment might be related to its neuroprotective effect after brain ischemia in mice.
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http://dx.doi.org/10.1016/j.brainresbull.2019.11.009DOI Listing
February 2020

A positive allosteric modulator of mGluR5 promotes neuroprotective effects in mouse models of Alzheimer's disease.

Neuropharmacology 2019 12 18;160:107785. Epub 2019 Sep 18.

Department of Pharmacology, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil. Electronic address:

Alzheimer's Disease (AD) is the most prevalent neurodegenerative disorder. Despite advances in the understanding of its pathophysiology, none of the available therapies prevents disease progression. Excess glutamate plays an important role in excitotoxicity by activating ionotropic receptors. However, the mechanisms modulating neuronal cell survival/death via metabotropic glutamate receptors (mGluRs) are not completely understood. Recent data indicates that CDPPB, a positive allosteric modulator of mGluR5, has neuroprotective effects. Thus, this work aimed to investigate CDPPB treatment effects on amyloid-β (Aβ) induced pathological alterations in vitro and in vivo and in a transgenic mouse model of AD (T41 mice). Aβ induced cell death in primary cultures of hippocampal neurons, which was prevented by CDPPB. Male C57BL/6 mice underwent stereotaxic surgery for unilateral intra-hippocampal Aβ injection, which induced memory deficits, neurodegeneration, neuronal viability reduction and decrease of doublecortin-positive cells, a marker of immature neurons and neuronal proliferation. Treatment with CDPPB for 8 days reversed neurodegeneration and doublecortin-positive cells loss and recovered memory function. Fourteen months old T41 mice presented cognitive deficits, neuronal viability reduction, gliosis and Aβ accumulation. Treatment with CDPPB for 28 days increased neuronal viability (32.2% increase in NeuN cells) and reduced gliosis in CA1 region (Iba-1 area by 31.3% and GFAP area by 37.5%) in transgenic animals, without inducing hepatotoxicity. However, it did not reverse cognitive deficit. Despite a four-week treatment did not prevent memory loss in aged transgenic mice, CDPPB is protective against Aβ stimulus. Therefore, this drug represents a potential candidate for further investigations as AD treatment.
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http://dx.doi.org/10.1016/j.neuropharm.2019.107785DOI Listing
December 2019

Lipopolysaccharide-Induced Neuroinflammation as a Bridge to Understand Neurodegeneration.

Int J Mol Sci 2019 May 9;20(9). Epub 2019 May 9.

Department of Pharmacology, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, Belo Horizonte 31270-901, Brazil.

A large body of experimental evidence suggests that neuroinflammation is a key pathological event triggering and perpetuating the neurodegenerative process associated with many neurological diseases. Therefore, different stimuli, such as lipopolysaccharide (LPS), are used to model neuroinflammation associated with neurodegeneration. By acting at its receptors, LPS activates various intracellular molecules, which alter the expression of a plethora of inflammatory mediators. These factors, in turn, initiate or contribute to the development of neurodegenerative processes. Therefore, LPS is an important tool for the study of neuroinflammation associated with neurodegenerative diseases. However, the serotype, route of administration, and number of injections of this toxin induce varied pathological responses. Thus, here, we review the use of LPS in various models of neurodegeneration as well as discuss the neuroinflammatory mechanisms induced by this toxin that could underpin the pathological events linked to the neurodegenerative process.
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http://dx.doi.org/10.3390/ijms20092293DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6539529PMC
May 2019

Role of Microglia TLRs in Neurodegeneration.

Front Cell Neurosci 2018 2;12:329. Epub 2018 Oct 2.

Department of Pharmacology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.

Toll-like receptors (TLRs) are a group of receptors widely distributed in the organism. In the central nervous system, they are expressed in neurons, astrocytes and microglia. Although their involvement in immunity is notorious, different articles have demonstrated their roles in physiological and pathological conditions, including neurodegeneration. There is increasing evidence of an involvement of TLRs, especially TLR2, 4 and 9 in neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). In this sense, their expression in microglia might modulate the activity of these cells, which in turn, lead to protective or deleterious effects over neurons and other cells. Therefore, TLRs might mediate the link between inflammation and neurodegenerative diseases. However, further studies have to be performed to elucidate the role of the other TLRs in these diseases and to further prove and confirm the pathophysiological role of all TLRs in neurodegeneration. In this article, we revise and summarize the current knowledge regarding the role of TLRs in neurodegeneration with the focus on the possible functions of these receptors in microglia.
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http://dx.doi.org/10.3389/fncel.2018.00329DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6176466PMC
October 2018

A high-refined carbohydrate diet facilitates compulsive-like behavior in mice through the nitric oxide pathway.

Nitric Oxide 2018 11 17;80:61-69. Epub 2018 Aug 17.

Laboratório de Neuropsicofarmacologia, Departamento de Farmacologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil. Electronic address:

Obesity is characterized by abnormal adipose tissue expansion and is associated with chronic inflammation. Obesity itself may induce several comorbidities, including psychiatric disorders. It has been previously demonstrated that proinflammatory cytokines are able to up-regulate inducible nitric oxide synthase (iNOS) and nitric oxide (NO) release, which both have a role in compulsive related behaviors.

Objective: To evaluate whether acute or chronic consumption of a high-refined carbohydrate-containing (HC) diet will modify burying-behavior in the Marble Burying Test (MBT) through augmentation of NO signaling in the striatum, a brain region related to the reward system. Further, we also verified the effects of chronic consumption of a HC diet on the reinforcing effects induced by cocaine in the Conditioned Place Preference (CPP) test.

Methods: Male BALB/c mice received a standard diet (control diet) or a HC diet for 3 days or 12 weeks.

Results: An increase in burying behavior occurred in the MBT after chronic consumption of a HC diet that was associated with an increase of nitrite levels in the striatum. The pre-treatment with Aminoguanidine (50 mg/kg), a preferential inhibitor of iNOS, prevented such alterations. Additionally, a chronic HC diet also induced a higher expression of iNOS in this region and higher glutamate release from striatal synaptosomes. Neither statistical differences were observed in the expression levels of the neuronal isoform of NOS nor in microglia number and activation. Finally, the reinforcing effects induced by cocaine (15 mg/kg, i.p.) during the expression of the conditioned response in the CPP test were not different between the chronically HC diet fed mice and the control group. However, HC diet-feeding mice presented impairment of cocaine-preference extinction.

Conclusion: Altogether, our results suggest that the chronic consumption of a HC diet induces compulsive-like behavior through a mechanism possibly associated with NO activation in the striatum.
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http://dx.doi.org/10.1016/j.niox.2018.08.008DOI Listing
November 2018

Inflammation as a Possible Link Between Dyslipidemia and Alzheimer's Disease.

Neuroscience 2018 04 14;376:127-141. Epub 2018 Feb 14.

Department of Pharmacology, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil. Electronic address:

Alzheimer's disease (AD) is the leading cause of dementia worldwide. This pathological condition is characterized not only by Aβ and tau accumulation in the central nervous system (CNS), but also by inflammation, processes that can lead to neurodegeneration. Besides that, other factors may contribute to the development of AD, such as dyslipidemias. Changes in lipid levels can either influence the activity of enzymes related to the protein deposition that occurs in this pathological condition, or enhance the peripheral and CNS immune responses. Furthermore, cholesterol-associated genes are frequently associated with AD. Here, we extensively reviewed the literature and, based on the existing evidences, we suggest inflammation as an important link between dyslipidemias and AD.
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http://dx.doi.org/10.1016/j.neuroscience.2018.02.012DOI Listing
April 2018

Design, synthesis and pharmacological evaluation of N-benzyl-piperidinyl-aryl-acylhydrazone derivatives as donepezil hybrids: Discovery of novel multi-target anti-alzheimer prototype drug candidates.

Eur J Med Chem 2018 Mar 31;147:48-65. Epub 2018 Jan 31.

Institute of Biological Sciences, Federal University of Minas Gerais, MG 31270-901, Brazil.

A new series of sixteen multifunctional N-benzyl-piperidine-aryl-acylhydrazones hybrid derivatives was synthesized and evaluated for multi-target activities related to Alzheimer's disease (AD). The molecular hybridization approach was based on the combination, in a single molecule, of the pharmacophoric N-benzyl-piperidine subunit of donepezil, the substituted hydroxy-piperidine fragment of the AChE inhibitor LASSBio-767, and an acylhydrazone linker, a privileged structure present in a number of synthetic aryl- and aryl-acylhydrazone derivatives with significant AChE and anti-inflammatory activities. Among them, compounds 4c, 4d, 4g and 4j presented the best AChE inhibitory activities, but only compounds 4c and 4g exhibited concurrent anti-inflammatory activity in vitro and in vivo, against amyloid beta oligomer (AβO) induced neuroinflammation. Compound 4c also showed the best in vitro and in vivo neuroprotective effects against AβO-induced neurodegeneration. In addition, compound 4c showed a similar binding mode to donepezil in both acetylated and free forms of AChE enzyme in molecular docking studies and did not show relevant toxic effects on in vitro and in vivo assays, with good predicted ADME parameters in silico. Overall, all these results highlighted compound 4c as a promising and innovative multi-target drug prototype candidate for AD treatment.
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http://dx.doi.org/10.1016/j.ejmech.2018.01.066DOI Listing
March 2018

Correction to: AM404, paracetamol metabolite, prevents prostaglandin synthesis in activated microglia by inhibiting COX activity.

J Neuroinflammation 2018 Feb 6;15(1):34. Epub 2018 Feb 6.

Department of Psychiatry and Psychotherapy, Laboratory of Translational Psychiatry, Faculty of Medicine, Medical Center, University of Freiburg, Hauptstr. 5, 79104, Freiburg, Germany.

After publication of the article [1], it has been brought to our attention that the caption for Figure 2 has been mistakenly replaced with a reproduction of the Figure 4 caption.
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http://dx.doi.org/10.1186/s12974-018-1072-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5801836PMC
February 2018

AM404, paracetamol metabolite, prevents prostaglandin synthesis in activated microglia by inhibiting COX activity.

J Neuroinflammation 2017 Dec 13;14(1):246. Epub 2017 Dec 13.

Department of Psychiatry and Psychotherapy, Laboratory of Translational Psychiatry, Faculty of Medicine, Medical Center - University of Freiburg, Hauptstr. 5, 79104, Freiburg, Germany.

Background: N-arachidonoylphenolamine (AM404), a paracetamol metabolite, is a potent agonist of the transient receptor potential vanilloid type 1 (TRPV1) and low-affinity ligand of the cannabinoid receptor type 1 (CB1). There is evidence that AM404 exerts its pharmacological effects in immune cells. However, the effect of AM404 on the production of inflammatory mediators of the arachidonic acid pathway in activated microglia is still not fully elucidated.

Method: In the present study, we investigated the effects of AM404 on the eicosanoid production induced by lipopolysaccharide (LPS) in organotypic hippocampal slices culture (OHSC) and primary microglia cultures using Western blot, immunohistochemistry, and ELISA.

Results: Our results show that AM404 inhibited LPS-mediated prostaglandin E (PGE) production in OHSC, and LPS-stimulated PGE release was totally abolished in OHSC if microglial cells were removed. In primary microglia cultures, AM404 led to a significant dose-dependent decrease in the release of PGE, independent of TRPV1 or CB1 receptors. Moreover, AM404 also inhibited the production of PGD and the formation of reactive oxygen species (8-iso-PGF alpha) with a reversible reduction of COX-1- and COX-2 activity. Also, it slightly decreased the levels of LPS-induced COX-2 protein, although no effect was observed on LPS-induced mPGES-1 protein synthesis.

Conclusions: This study provides new significant insights about the potential anti-inflammatory role of AM404 and new mechanisms of action of paracetamol on the modulation of prostaglandin production by activated microglia.
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http://dx.doi.org/10.1186/s12974-017-1014-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5729401PMC
December 2017

Activation of EP receptor suppresses poly(I: C) and LPS-mediated inflammation in primary microglia and organotypic hippocampal slice cultures: Contributing role for MAPKs.

Glia 2018 04 11;66(4):708-724. Epub 2017 Dec 11.

Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hauptstr. 5, Freiburg, D-79104, Germany.

Brain inflammation is a critical factor involved in neurodegeneration. Recently, the prostaglandin E (PGE ) downstream members were suggested to modulate neuroinflammatory responses accompanying neurodegenerative diseases. In this study, we investigated the protective effects of prostaglandin E receptor 2 (EP ) during TLR3 and TLR4-driven inflammatory response using in vitro primary microglia and ex vivo organotypic hippocampal slice cultures (OHSCs). Depletion of microglia from OHSCs differentially affected TLR3 and TLR4 receptor expression. Poly(I:C) induced the production of prostaglandin E in OHSCs by increasing cyclooxygenase (COX-2) and microsomal prostaglandin E synthase (mPGES)-1. Besides, stimulation of OHSCs and microglia with Poly(I:C) upregulated EP receptor expression. Co-stimulation of OHSCs and microglia with the EP agonist butaprost reduced inflammatory mediators induced by LPS and Poly(I:C). In Poly(I:C) challenged OHSCs, butaprost almost restored microglia ramified morphology and reduced Iba1 immunoreactivity. Importantly, microglia depletion prevented the induction of inflammatory mediators following Poly(I:C) or LPS challenge in OHSCs. Activation of EP receptor reversed the Poly(I:C)/LPS-induced phosphorylation of the mitogen activated protein kinases (MAPKs) ERK, p38 MAPK and c-Jun N-terminal kinase (JNK) in microglia. Collectively, these data identify an anti-inflammatory function for EP signaling in diverse innate immune responses, through a mechanism that involves the mitogen-activated protein kinases pathway.
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http://dx.doi.org/10.1002/glia.23276DOI Listing
April 2018

Cannabinoid receptor 1/2 double-knockout mice develop epilepsy.

Epilepsia 2017 12 3;58(12):e162-e166. Epub 2017 Nov 3.

Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, U.S.A.

The endocannabinoid system has gained attention as an important modulator of activity in the central nervous system. Initial studies focused on cannabinoid receptor 1 (CB1), which is widely expressed in the brain, but recent work also implicates cannabinoid receptor 2 (CB2) in modulating neuronal activity. Both receptors are capable of reducing neuronal activity, generating interest in cannabinoid receptor agonists as potential anticonvulsants. CB1 (Cnr1) and CB2 (Cnr2) single-knockout mice have been generated, with the former showing heightened seizure sensitivity, but not overt seizures. Given overlapping and complementary functions of CB1 and CB2 receptors, we queried whether double-knockout mice would show an exacerbated neurological phenotype. Strikingly, 30% of double-knockout mice exhibited provoked behavioral seizures, and 80% were found to be epileptic following 24/7 video-electroencephalographic monitoring. Single-knockout animals did not exhibit seizures. These findings highlight the importance of the endocannabinoid system for maintaining network stability.
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http://dx.doi.org/10.1111/epi.13930DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5716894PMC
December 2017

Two-hit model of schizophrenia induced by neonatal immune activation and peripubertal stress in rats: Study of sex differences and brain oxidative alterations.

Behav Brain Res 2017 07 17;331:30-37. Epub 2017 May 17.

Drug Research and Development Center, Department of Physiology and Pharmacology, Universidade Federal do Ceará, Fortaleza, CE, Brazil; National Institute for Translational Medicine (INCT-TM, CNPq), Brazil. Electronic address:

Schizophrenia is considered to be a developmental disorder with distinctive sex differences. Aiming to simulate the vulnerability of the third trimester of human pregnancy to the developmental course of schizophrenia, an animal model was developed, using neonatal poly(I:C) as a first-hit, and peripubertal stress as a second-hit, i.e. a two-hit model. Since, to date, there have been no references to sex differences in the two-hit model, our study sought to determine sex influences on the development of behavior and brain oxidative change in adult rats submitted to neonatal exposure to poly(I:C) on postnatal days 5-7 as well as peripubertal unpredictable stress (PUS). Our results showed that adult two-hit rats present sex-specific behavioral alterations, with females showing more pronounced deficits in prepulse inhibition of the startle reflex and hyperlocomotion, while males showing more deficits in social interaction. Male and female animals exhibited similar working memory deficits. The levels of the endogenous antioxidant, reduced glutathione, were decreased in the prefrontal cortex (PFC) of both male and female animals exposed to both poly(I:C) and poly(I:C)+PUS. Only females presented decrements in GSH levels in the striatum. Nitrite levels were increased in the PFC of male and in the striatum of female poly(I:C)+PUS rats. Increased lipid peroxidation was observed in the PFC of females and in the striatum of males and females exposed to poly(I:C) and poly(I:C)+PUS. Thus, the present study presents evidence for sex differences in behavior and oxidative brain change induced by a two-hit model of schizophrenia.
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http://dx.doi.org/10.1016/j.bbr.2017.04.057DOI Listing
July 2017

Antidepressant-like effect of valproic acid-Possible involvement of PI3K/Akt/mTOR pathway.

Behav Brain Res 2017 06 11;329:166-171. Epub 2017 Apr 11.

Department of Pharmacology, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil. Electronic address:

Rationale: Few studies suggest that antidepressants exert their effects by activating some signaling pathways, including the phosphatidylinositol 3-kinase (PI3K). Moreover, valproic acid (VPA) activates the PI3K pathway. Thus, here we investigated the antidepressant-like effect of VPA and if its effect is related to PI3K/Akt/mTOR activation.

Methods: C57Bl/6 (WT) and PI3Kγ mice received VPA injections (30, 100 or 300mg/kg, i.p.) and 30min after they were submitted to the forced swimming (FS), tail suspension (TS) and open field (OF) tests. Another group was pretreated with rapamycin (5mg/kg, i.p.) 150min before VPA administration. Akt phosphorylation levels were measured by Western blotting.

Results: In WT mice, VPA (30mg/kg) reduced the immobility time in both FS and TS tests. However, VPA (300mg/kg) increased the immobility time in FS test. All doses of VPA did not alter locomotor activity. In PI3Kγ mice, none of the doses revealed antidepressant-like effect. However, in the OF test, the lower dose of VPA increased the travelled distance in comparison with vehicle group. An increase in Akt phosphorylation levels was observed in WT, but not in PI3Kγ mice. Finally, the pretreatment of WT mice with rapamycin abolished the antidepressant-like effect of VPA (30mg/kg) in FS test.

Conclusion: These data suggest that the antidepressant-like effects of VPA might depend on PI3K and mTOR activation. Thus, more studies are necessary to investigate the mechanisms involved in the antidepressant-like effect induced by VPA in order to investigate novel therapeutic targets for the treatment of depression.
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http://dx.doi.org/10.1016/j.bbr.2017.04.015DOI Listing
June 2017

Knockdown of C-C Chemokine Receptor 5 (CCR5) is Protective Against Cerebral Ischemia and Reperfusion Injury.

Curr Neurovasc Res 2017 ;14(2):125-131

Universidade Federal de Minas Gerais, Instituto de Ciencias Biologicas. Departamento de Patologia Geral. Laboratorio de Apoptose. Campus Pampulha, Av. Antonio Carlos 6.627 - Belo Horizonte, Minas Gerais. Brazil.

Background: Stroke is the second leading cause of death and a major cause of disability of adults worldwide. Inflammatory processes are known to contribute to the pathophysiology of cerebral ischemia, especially following reperfusion. Chemokines and their receptors are involved in migration of leukocytes and have been implicated in the pathogenesis of ischemic stroke.

Objective: In the present study, we investigated the effects of C-C chemokine receptor type 5 (CCR5) deficiency on neurological outcome, brain damage and expression of pro-inflammatory chemokines: chemokine (C-X-C motif) ligand 1 (CXCL1), chemokine (CC motif) ligand 3 (CCL3) and chemokine (C-C motif) ligand 5 (CCL5), and the brain-derived neurotrophic factor (BDNF).

Methods: Adult male C57BL/6 (wild-type) (WT) and CCR5 deficient mice were subjected to transient cerebral ischemia induced by 25 min of bilateral common carotid artery occlusion (BCCAO) followed by 24 hours of reperfusion. Mice were divided into four groups: WT sham group, which underwent sham operation; WT ischemic group, which was subjected to transient bilateral common carotid artery occlusion, CCR5-/- sham group, which underwent sham operation, and CCR5-/- ischemic group, which was subjected to transient BCCAO.

Results: In CCR5 deficiency, we observed a significant improvement in the neurological deficits associated with decreased brain infarcted area as evaluated by triphenyltetrazolium chloride (TTC). Moreover, CCR5 deficiency revealed decreased percentage of necrotic cavities areas and frequency of ischemic neurons by histometric analysis. In addition, CCR5-/- ischemic animals showed lower brain levels of the chemokine CXCL1 and higher levels of BDNF by ELISA, compared with WT BCCAo mice.

Conclusion: Taken together, our results suggest a potential neuroprotection in the absence of CCR5 receptor during global brain ischemia and reperfusion injury.
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http://dx.doi.org/10.2174/1567202614666170313113056DOI Listing
March 2018

Neuroprotective effects of intrastriatal injection of rapamycin in a mouse model of excitotoxicity induced by quinolinic acid.

J Neuroinflammation 2017 01 31;14(1):25. Epub 2017 Jan 31.

Department of Pharmacology, Universidade Federal de Minas Gerais, Avenida Antonio Carlos, 6627, 31270-901, Belo Horizonte, MG, Brazil.

Background: The mammalian target of rapamycin (mTOR) is a kinase involved in a variety of physiological and pathological functions. However, the exact role of mTOR in excitotoxicity is poorly understood. Here, we investigated the effects of mTOR inhibition with rapamycin against neurodegeneration, and motor impairment, as well as inflammatory profile caused by an excitotoxic stimulus.

Methods: A single and unilateral striatal injection of quinolinic acid (QA) was used to induce excitotoxicity in mice. Rapamycin (250 nL of 0.2, 2, or 20 μM; intrastriatal route) was administered 15 min before QA injection. Forty-eight hours after QA administration, rotarod test was performed to evaluate motor coordination and balance. Fluoro-Jade C, Iba-1, and GFAP staining were used to evaluate neuronal cell death, microglia morphology, and astrocytes density, respectively, at this time point. Levels of cytokines and neurotrophic factors were measured by ELISA and Cytometric Bead Array 8 h after QA injection. Striatal synaptosomes were used to evaluate the release of glutamate.

Results: We first demonstrated that rapamycin prevented the motor impairment induced by QA. Moreover, mTOR inhibition also reduced the neurodegeneration and the production of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α induced by excitotoxic stimulus. The lowest dose of rapamycin also increased the production of IL-10 and prevented the reduction of astrocyte density induced by QA. By using an in vitro approach, we demonstrated that rapamycin differently alters the release of glutamate from striatal synaptosomes induced by QA, reducing or enhancing the release of this neurotransmitter at low or high concentrations, respectively.

Conclusion: Taken together, these data demonstrated a protective effect of rapamycin against an excitotoxic stimulus. Therefore, this study provides new evidence of the detrimental role of mTOR in neurodegeneration, which might represent an important target for the treatment of neurodegenerative diseases.
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http://dx.doi.org/10.1186/s12974-017-0793-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5282622PMC
January 2017

Postictal alterations induced by intrahippocampal injection of pilocarpine in C57BL/6 mice.

Epilepsy Behav 2016 11 11;64(Pt A):83-89. Epub 2016 Oct 11.

Department of Pharmacology, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil. Electronic address:

Temporal lobe epilepsy (TLE) is the most common form of epilepsy in adults. The pilocarpine (PILO) experimental model of TLE portrays behavioral and pathophysiological changes in rodents that are very similar to those found in humans with TLE. However, this model is associated with an unfortunate high mortality rate. Studies have shown that intrahippocampal injection of PILO, while having a much smaller mortality rate, induces status epilepticus (SE) that secondarily leads to TLE. To the best of our knowledge, the present study was the first to evaluate the cognitive and histological alterations 72h after intrahippocampal microinjection of PILO in C57BL/6 mice. Seventy percent of mice developed status epilepticus (SE) after PILO administration, and all animals survived after SE. Seventy-two hours after SE, mice presented memory impairment in both Novel Object Recognition (recognition index - vehicle: 67.57±4.46% vs PILO: 52.33±3.29%) and Contextual Fear Conditioning (freezing time - vehicle: 203±20.43 vs PILO: 107.80±25.17s) tasks. Moreover, using Nissl and NeuN staining, we observed in PILO-treated mice a significant decrease in cell viability and an increase in neuronal loss in all three hippocampal regions analyzed, cornus ammonis (CA) 1, CA3, and dentate gyrus (DG), in comparison with the control group. Additionally, using Iba-1 staining, we observed in PILO-treated mice a significant increase in microglial proliferation in CA1, CA3, and DG of the hippocampus. Therefore, intrahippocampal PILO microinjection is an efficient route to induce SE and acute postictal epileptogenic-like alterations in C57BL/6 mice.
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http://dx.doi.org/10.1016/j.yebeh.2016.08.003DOI Listing
November 2016

Neurodegeneration Alters Metabolic Profile and Sirt 1 Signaling in High-Fat-Induced Obese Mice.

Mol Neurobiol 2017 07 16;54(5):3465-3475. Epub 2016 May 16.

Institute of Agricultural Sciences. Food Engineering College, Universidade Federal de Minas Gerais (UFMG), Montes Claros, Minas Gerais, Brazil.

Different factors may contribute to the development of neurodegenerative diseases. Among them, metabolic syndrome (MS), which has reached epidemic proportions, has emerged as a potential element that may be involved in neurodegeneration. Furthermore, studies have shown the importance of the sirtuin family in neuronal survival and MS, which opens the possibility of new pharmacological targets. This study investigates the influence of sirtuin metabolic pathways by examining the functional capacities of glucose-induced obesity in an excitotoxic state induced by a quinolinic acid (QA) animal model. Mice were divided into two groups that received different diets for 8 weeks: one group received a regular diet, and the other group received a high-fat diet (HF) to induce MS. The animals were submitted to a stereotaxic surgery and subdivided into four groups: Standard (ST), Standard-QA (ST-QA), HF and HF-QA. The QA groups were given a 250 nL quinolinic acid injection in the right striatum and PBS was injected in the other groups. Obese mice presented with a weight gain of 40 % more than the ST group beyond acquiring an insulin resistance. QA induced motor impairment and neurodegeneration in both ST-QA and HF-QA, although no difference was observed between these groups. The HF-QA group showed a reduction in adiposity when compared with the groups that received PBS. Therefore, the HF-QA group demonstrated a commitment-dependent metabolic pathway. The results suggest that an obesogenic diet does not aggravate the neurodegeneration induced by QA. However, the excitotoxicity induced by QA promotes a sirtuin pathway impairment that contributes to metabolic changes.
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http://dx.doi.org/10.1007/s12035-016-9927-xDOI Listing
July 2017

Neuroprotective effects of the anticancer drug NVP-BEZ235 (dactolisib) on amyloid-β 1-42 induced neurotoxicity and memory impairment.

Sci Rep 2016 05 4;6:25226. Epub 2016 May 4.

Department of Pharmacology, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, Brazil.

Alzheimer's Disease (AD) is a progressive neurodegenerative disease and the main cause of dementia. Substantial evidences indicate that there is over-activation of the PI3K/Akt/mTOR axis in AD. Therefore, the aim of the present study was to investigate the effects of NVP-BEZ235 (BEZ; dactolisib), a dual PI3K/mTOR inhibitor that is under phase I/II clinical trials for the treatment of some types of cancer, in hippocampal neuronal cultures stimulated with amyloid-β (Aβ) 1-42 and in mice injected with Aβ 1-42 in the hippocampus. In cell cultures, BEZ reduced neuronal death induced by Aβ. BEZ, but not rapamycin, a mTOR inhibitor, or LY294002, a PI3K inhibitor that also inhibits mTOR, reduced the memory impairment induced by Aβ. The effect induced by Aβ was also prevented in PI3Kγ(-/-) mice. Neuronal death and microgliosis induced by Aβ were reduced by BEZ. In addition, the compound increased IL-10 and TNF-α levels in the hippocampus. Finally, BEZ did not change the phosphorylation of Akt and p70s6K, suggesting that the involvement of PI3K and mTOR in the effects induced by BEZ remains controversial. Therefore, BEZ represents a potential strategy to prevent the pathological outcomes induced by Aβ and should be investigated in other models of neurodegenerative conditions.
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http://dx.doi.org/10.1038/srep25226DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4855228PMC
May 2016

Poly(I:C) increases the expression of mPGES-1 and COX-2 in rat primary microglia.

J Neuroinflammation 2016 Jan 18;13:11. Epub 2016 Jan 18.

Department of Psychiatry, University of Freiburg Medical School, Hauptstr. 5, 79104, Freiburg, Germany.

Background: Microglia recognize pathogen-associated molecular patterns such as double-stranded RNA (dsRNA) present in some viruses. Polyinosinic-polycytidylic acid [poly(I:C)] is a synthetic analog of dsRNA that activates different molecules, such as retinoic acid-inducible gene I, melanoma differentiation-associated gene 5, and toll-like receptor-3 (TLR3). Poly(I:C) increases the expression of different cytokines in various cell types. However, its role in the regulation of the production of inflammatory mediators of the arachidonic acid pathway by microglia is poorly understood.

Methods: In the present study, we evaluated the effect of poly(I:C) on the production of prostaglandin E2 (PGE2) and the inducible enzymes cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase-1 (mPGES-1) in primary rat microglia. Microglia were stimulated with different concentrations of poly(I:C) (0.1-10 μg/ml), and the protein levels of COX-2 and mPGES-1, as well as the release of PGE2, were determined by western blot and enzyme immunoassay (EIA), respectively. Values were compared using one-way ANOVA with post hoc Student-Newman-Keuls test.

Results: Poly(I:C) increased the production of PGE2, as well as mPGES-1 and COX-2 synthesis. To investigate the mechanisms involved in poly(I:C)-induced COX-2 and mPGES-1, we studied the effects of various signal transduction pathway inhibitors. Protein levels of COX-2 and mPGES-1 were reduced by SB203580, SP600125, and SC514 (p38 mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase (JNK), and IκB kinase (IKK) inhibitors, respectively), as well as by PD98059 and PD0325901 (mitogen-activated protein kinase kinase (MEK) inhibitors). Rapamycin, a mammalian target of rapamycin (mTOR) inhibitor, enhanced the synthesis of COX-2. Inhibition of phosphatidylinositol 3-kinase (PI3K) by LY294002 or dual inhibition of PI3K/mTOR (with NVP-BEZ235) enhanced COX-2 and reduced mPGES-1 immunoreactivity. To confirm the data obtained with the inhibitors, we studied the phosphorylation of the blocked kinases by western blot. Poly(I:C) increased the phosphorylation of p38 MAPK, extracellular signal-regulated kinase (ERK), JNK, protein kinase B (Akt), and IκB.

Conclusions: Taken together, our data demonstrate that poly(I:C) increases the synthesis of enzymes involved in PGE2 synthesis via activation of different signaling pathways in microglia. Importantly, poly(I:C) activates similar pathways also involved in TLR4 signaling that are important for COX-2 and mPGES-1 synthesis. Thus, these two enzymes and their products might contribute to the neuropathological effects induced in response to dsRNA, whereby the engagement of TLR3 might be involved.
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http://dx.doi.org/10.1186/s12974-015-0473-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4717620PMC
January 2016

microRNA-26a modulates inflammatory response induced by toll-like receptor 4 stimulation in microglia.

J Neurochem 2015 Dec 14;135(6):1189-202. Epub 2015 Oct 14.

Department of Psychiatry, Neurochemistry Lab, University of Freiburg Medical School, Freiburg, Germany.

MiRNAs, a family of small non-coding RNAs, have emerged as novel post-transcriptional regulators of numerous cellular responses. Although the involvement of miRNAs in the regulation of neuroinflammation in various neurological diseases has been previously studied, their role in the production of inflammatory mediators during microglia activation is poorly understood. In this study, the role of miR-26a has been investigated in the modulation of inflammatory response in cultured microglia. Using real-time PCR, the expression of miR-26a was studied in toll-like receptors 4 stimulated primary mouse microglia. miR-26a expression was found to be rapidly reduced after the stimulation of toll-like receptors 4 in microglia. Over-expression of miR-26a significantly decreased the production of inflammatory cytokines such as tumor necrosis factor α and IL-6, whereas knockdown of miR-26a increased the expression of these mediators. Furthermore, using in silico analysis, we identified that the activating transcription factor (ATF) 2 is directly targeted by miR-26a. This finding was confirmed by loss and gain of function studies. Similar to the effect of miR-26a over-expression, knockdown of activating transcription factor 2 inhibited the production of proinflammatory cytokines, particularly IL-6. Taken together, our results suggest the involvement of miR-26a in the regulation of the production of proinflammatory cytokines in microglia. We proposed that in microglia, activation of toll-like receptor 4 (TLR4) by lipopolysaccharide (LPS) down-regulates miR-26a. The down-regulation of this miR increases expression of activating transcription factor 2 (ATF2). This event, in addition to the activation of ATF2 by c-Jun N-terminal kinase (JNK), increases interleukin-6 (IL-6) production. On the other hand, miR-26a also increases the production of tumor necrosis factor α (TNFα) by a mechanism independent of ATF2.
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http://dx.doi.org/10.1111/jnc.13364DOI Listing
December 2015

Neuroinflammation and Neurodegeneration: Pinpointing Pathological and Pharmacological Targets.

Biomed Res Int 2015 30;2015:487241. Epub 2015 Jul 30.

Department of Pharmacology, Federal University of State Minas Gerais, Avenida Antonio Carlos 6627, 31270-901 Belo Horizonte, MG, Brazil.

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http://dx.doi.org/10.1155/2015/487241DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4534599PMC
May 2016

The 5-lipoxygenase (5-LOX) Inhibitor Zileuton Reduces Inflammation and Infarct Size with Improvement in Neurological Outcome Following Cerebral Ischemia.

Curr Neurovasc Res 2015 ;12(4):398-403

Universidade Federal de Minas Gerais, Instituto de Ciencias Biologicas. Departamento de Patologia Geral. Laboratorio de Apoptose, Campus Pampulha, Av. Antonio Carlos 6.627 - Belo Horizonte, Minas Gerais. Brazil.

Stroke is one of the most frequent causes of death and disability worldwide causing a major clinical and socioeconomic impact. Although the pathophysiology of brain ischemia and reperfusion is complex, the inflammatory process plays an important role in pathogenesis, contributing to the expansion of brain injury. The 5-lipoxygenase (5-LOX) is a key enzyme in the biosynthesis of the leukotrienes and has been implicated and in the central nervous system (CNS) disorders such as Alzheimer's disease and acute ischemic stroke. Zileuton, a selective 5-LOX inhibitor, has antiinflammatory properties and exerts an inhibitory effect on inflammatory diseases. The objective of this study was to evaluate the effects of blocking 5-LOX activity in a murine model of transient and global brain ischemia. Zileuton improved neurological deficits and significantly decrease volume and density of lesion, compared to vehicle-ischemic animals measured by magnetic resonance imaging (MRI). In addition, the blockage of 5-LOX reduced infarct area and histopathological changes. Furthermore, by enzyme immunoassay (ELISA) increased brain levels of tumor necrosis factor-alpha (TNFalpha), interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta), interleukin-6 (IL-6), chemokine (C-X-C motif) ligand 1 (CXCL1), chemokine (C-C motif) ligand 3 (CCL3) and chemokine (C-C motif) ligand 5 (CCL5) were detected in the vehicle-ischemic group, whereas in Zileuton-ischemic group presented reduction of these mediators. The concentration of the antiinflammatory cytokine interleukin-10 (IL-10) was increased after 5-LOX inhibition. Our results suggest that Zileuton decreases brain damage and reduces inflammatory cytokines expression in the CNS which contributes, at least in part, to improve the neurological outcome of brain ischemia.
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http://dx.doi.org/10.2174/1567202612666150812150606DOI Listing
June 2016

Wistar Audiogenic Rats (WAR) exhibit altered levels of cytokines and brain-derived neurotrophic factor following audiogenic seizures.

Neurosci Lett 2015 Jun 30;597:154-8. Epub 2015 Apr 30.

Department of Pharmacology, Brazil. Electronic address:

Increasing body of evidence suggests that inflammatory and neurotrophic factors might be important for epileptogenesis. Most animal studies demonstrated altered levels of these mediators in drug-induced models of seizures and epilepsy. In the present study, we investigated the production of cytokines and a neurotrophin in the brain of Wistar Audiogenic Rats (WAR), a genetic model of epilepsy, stimulated with high-intensity sound. Four hours after stimulation, animals were decapitated and the hippocampus, inferior colliculus, striatum and cortex were removed for evaluation of the levels of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α and brain derived neurotrophic factor (BDNF). All the cytokines and BDNF levels were increased in the cortex. Increased levels of TNF-α and IL-6 were also observed in the striatum. Finally, TNF-α also increased in the inferior colliculus after the seizures induced by high-intensity sound. Although different studies have demonstrated that the levels of cytokines and BDNF increase in animal models of epilepsy induced by chemical stimuli, we provided here evidence that these mediators are also increased in WAR, a genetic model of epilepsy. Thus, the observed increase in these mediators might be involved in the pathophysiology of epilepsy.
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http://dx.doi.org/10.1016/j.neulet.2015.04.046DOI Listing
June 2015