[Show abstract][Hide abstract] ABSTRACT: Experimental cerebral malaria (ECM) is characterized by a strong immune response, with leukocyte recruitment, blood-brain barrier breakdown and hemorrhage in the central nervous system. Phosphatidylinositol 3-kinase γ (PI3Kγ) is central in signaling diverse cellular functions. Using PI3Kγ-deficient mice (PI3Kγ-/-) and a specific PI3Kγ inhibitor, we investigated the relevance of PI3Kγ for the outcome and the neuroinflammatory process triggered by Plasmodium berghei ANKA (PbA) infection. Infected PI3Kγ-/- mice had greater survival despite similar parasitemia levels in comparison with infected wild type mice. Histopathological analysis demonstrated reduced hemorrhage, leukocyte accumulation and vascular obstruction in the brain of infected PI3Kγ-/- mice. PI3Kγ deficiency also presented lower microglial activation (Iba-1+ reactive microglia) and T cell cytotoxicity (Granzyme B expression) in the brain. Additionally, on day 6 post-infection, CD3+CD8+ T cells were significantly reduced in the brain of infected PI3Kγ-/- mice when compared to infected wild type mice. Furthermore, expression of CD44 in CD8+ T cell population in the brain tissue and levels of phospho-IkB-α in the whole brain were also markedly lower in infected PI3Kγ-/- mice when compared with infected wild type mice. Finally, AS605240, a specific PI3Kγ inhibitor, significantly delayed lethality in infected wild type mice. In brief, our results indicate a pivotal role for PI3Kγ in the pathogenesis of ECM.
PLoS ONE 03/2015; 10(3):e0119633. DOI:10.1371/journal.pone.0119633 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Pneumococcal meningitis is associated with neurologic sequelae, such as, learning and memory impairment. Most currently a nonbacteriolytic antibiotic has been investigated to minimize inflammatory host response and prevented cognitive damage. In the present study, we compared daptomycin (DPTO) or ceftriaxone (CFX) treatment on inflammatory parameters and on blood-brain barrier (BBB) integrity in experimental pneumococcal meningitis. In the first step, the animals received an intracisternal (i.c.) injection of 10 µl of a S. pneumoniae suspension and were treated with CFX or DPTO at 18 h and were killed at 18, 20, 24, 36 and 40 h. In the hippocampus, tumor necrosis factor-alpha (TNF-α), Interleukin-6 (IL-6), IL-10 and brain-derived neurotrophic factor (BDNF) levels were not different between both treatments, however, IL-4 and CINC-1 levels decreased in CFX group. In frontal cortex, TNF-α, IL-4, IL-6, IL-10 and BDNF levels were not different between both treatments. Only cytokine-induced neutrophil chemoattractant-1 (CINC-1) levels decreased at 40 h with CFX treatment. In the second step the animals received DPTO or CFX during 7 days and were killed 10 days after induction. TNF-α, IL-6, IL-10, CINC-1 and BDNF levels were not different between both treatments in the hippocampus, however, IL-4 levels decreased in CFX treatment. In the third step: the animals received by i.c. 10 µl of a S. pneumoniae suspension or artificial CSF and were treated with CFX or DTPO with a single dose of antibiotic and BBB breakdown was assessed; however both antibiotics prevented the BBB disruption. Equally both treatments protected the BBB integrity and there were no significant difference in cytokines production.
Current Neurovascular Research 05/2014; 11(3). DOI:10.2174/1567202611666140520123424 · 2.74 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Infection with Plasmodium falciparum may result in severe disease affecting various organs, including liver, spleen, and brain, resulting in high morbidity and
mortality. Plasmodium berghei Anka infection of mice recapitulates many features of severe human malaria. The aryl hydrocarbon receptor (AhR) is an intracellular
receptor activated by ligands important in the modulation of the inflammatory response. We found that AhR-knockout (KO) mice
infected with P. berghei Anka displayed increased parasitemia, earlier mortality, enhanced leukocyte-endothelial cell interactions in the brain microvasculature,
and increased inflammation in brain (interleukin-17 [IL-17] and IL-6) and liver (gamma interferon [IFN-γ] and tumor necrosis
factor alpha [TNF-α]) compared to infected wild-type (WT) mice. Infected AhR-KO mice also displayed a reduction in cytokines
required for host resistance, including TNF-α, IL-1β, and IFN-γ, in the brain and spleen. Infection of AhR-KO mice resulted
in an increase in T regulatory cells and transforming growth factor β, IL-6, and IL-17 in the brain. AhR modulated the basal
expression of SOCS3 in spleen and brain, and P. berghei Anka infection resulted in enhanced expression of SOCS3 in brain, which was absent in infected AhR-KO mice. These data suggest
that AhR-mediated control of SOCS3 expression is probably involved in the phenotype seen in infected AhR-KO mice. This is,
to our knowledge, the first demonstration of a role for AhR in the pathogenesis of malaria.
Infection and immunity 05/2014; 82(8). DOI:10.1128/IAI.01733-14 · 4.16 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVES: Evaluate the levels of a neurotrophic factor and some neurotrophins in the plasma of patients with Autism Spectrum Disorders (ASD). DESIGN: This study enrolled 30 children with ASD and 19 healthy children. Plasma levels of the neurotrophins BDNF, NGF, NT3, NT4 and of the neurotrophic factor GDNF were measured by Enzyme-Linked Immunosorbent Assay. SETTING: The etiopathogenesis of ASD is largely unknown, but it seems to involve dysfunction in several biological systems. One of these systems comprises the neurotrophic factors, which are molecules involved in many processes in the central nervous system, including neuronal survival, synaptogenesis and synaptic plasticity. Recent studies have shown association between neurotrophic factors and ASD. RESULTS: No differences in plasma BDNF, NGF, NT3, NT4 and GDNF were found between ASD and control. Neurotrophic factors are not altered in ASD. CONCLUSIONS: These molecules may play a minor role in ASD.
[Show abstract][Hide abstract] ABSTRACT: Cerebral malaria (CM) is a clinical syndrome resulting from Plasmodium falciparum infection. A wide range of clinical manifestations follow the disease including cognitive dysfunction, seizures and coma. CM pathogenesis remains incompletely understood and without treatment this condition is invariably fatal. Artesunate has been accepted as the most effective drug for treating severe malaria. Besides its antiparasitic activity, an anti-inflammatory property has also been reported. In the current study, the immunomodulatory role of artesunate was investigated using a Plasmodium berghei ANKA model of CM, trough evaluation of behavioural changes and cytokines expression in hippocampus and in frontal cortex.
C57Bl/6 mice were infected with P. berghei by intraperitoneal route, using a standardized inoculation of 106 parasitized erythrocytes. Memory function was evaluated using the step-down inhibitory avoidance test. The mRNA expression of IFN-gamma, IL-1beta, IL-6 and TNF in the frontal cortex and hippocampus of control and infected mice on day 5 post-infection were estimated by quantitative real time PCR. Plasmodium berghei -infected mice also received intraperitoneally a single dose of artesunate (32 mg/kg) on day 4 post-infection, and 24 hours after treatment behavioural and immunological analysis were performed. The protein levels of cytokines IL-2, IL-6, IL-10, IL-17, IFN-gamma, TNF in the serum, frontal cortex and hippocampus of controls and P. berghei -infected mice treated or not treated with artesunate were determined using a cytometric bead array (CBA) kit. The survival and neurological symptoms of CM were also registered.
CM mice presented a significant impairment of aversive memory compared to controls on day 5 post-infection. A higher mRNA expression of pro-inflammatory cytokines was found in the hippocampus and frontal cortex of infected mice. A single dose of artesunate was also able to decrease the expression of inflammatory cytokines in the hippocampus and frontal cortex of P. berghei-infected mice. In parallel, a significant improvement in neurological symptoms and survival were observed in artesunate treated mice.
In summary, the current study provided further evidence that CM affects key brain areas related to cognition process. In addition, different patterns of cytokine expression during the course of CM could be modulated by a single administration of the anti-malarial artesunate.
[Show abstract][Hide abstract] ABSTRACT: Ischemic stroke may result from transient or permanent reductions of regional cerebral blood flow. Polymorphonuclear neutrophils have been described as the earliest inflammatory cells to arrive in ischemic tissue. CXCR1/2 receptors are involved in the recruitment of these cells. However, the contribution of these chemokine receptors during transient brain ischemia in mice remains poorly understood. In this work, we investigated the effects of reparixin, an allosteric antagonist of CXCR1/2 receptors, in a model of middle cerebral artery occlusion and reperfusion in mice.
C57BL/6J male mice treated with reparixin or vehicle were subjected to a middle cerebral artery occlusion procedure 1 h after the treatment. Ninety minutes after ischemia induction, the monofilament that prevented blood flow was removed. Twenty-four hours after the reperfusion procedure, behavioral changes, including motor signs, were analyzed with the SmithKline/Harwell/lmperial College/Royal Hospital/Phenotype Assessment (SHIRPA) battery. The animals were sacrificed, and brain tissue was removed for histological and biochemical analyses. Histological sections were stained with hematoxylin and eosin, neutrophil infiltration was estimated by myeloperoxidase activity and the inflammatory cytokine IL-iβ was measured by ELISA.
Pre-treatment with reparixin reduced the motor deficits observed in this model of ischemia and reperfusion. Myeloperoxidase activity and IL-iβ were reduced in the reparixin-treated group. Histological analysis revealed that ischemic injury was also attenuated by reparixin pre-treatment.
Our results suggest that the blockade of the CXCR1/2 receptors by reparixin promotes neuroprotective effects by reducing the levels of polymorphonuclear infiltration in the brain and the tissue damage associated with middle cerebral artery occlusion and reperfusion.
[Show abstract][Hide abstract] ABSTRACT: Background
The neuroinflammatory response aimed at clearance of herpes simplex virus-1 (HSV-1) plays a key role in the pathogenesis of neuroaxonal damage in herpetic encephalitis. Leukocytes activated in an adaptive immune response access brain tissue by passing through the blood–brain barrier. The chemokine CCL5/RANTES is involved in recruitment of these cells to the brain acting via the receptors CCR1, CCR3 and mainly CCR5. Here, we evaluated the role of CCR5 on traffic of leukocytes in the brain microvasculature, cellular and cytokines profile in a severe form of herpetic encephalitis.
Wild type and mice lacking CCR5 (CCR5-/-) were inoculated intracerebrally with 104 PFU of neurotropic HSV-1. We evaluated the traffic of leukocytes in the brain microvasculature using intravital microscopy and the profile of cytokines by Enzyme-Linked Immunosorbent Assay at 1 day post infection. Flow cytometry and histopathological analyses were also carried out in brain tissue. Absence of CCR5 leads to lower viral load and an increased leukocyte adhesion in brain microvasculature, predominantly of neutrophils (CD11+ Ly6G+ cells). Moreover, there was a significant increase in the levels of MIP-1/CCL2, RANTES/CCL5, KC/CXCL1 and MIG/CXCL9 in the brain of infected CCR5-/- mice.
These results suggest that the absence of CCR5 may boost the immune response with a high neutrophil recruitment which most likely helps in viral clearance. Nonetheless, the elevated immune response may be detrimental to the host.
[Show abstract][Hide abstract] ABSTRACT: Sepsis can lead to long-term cognitive changes, including memory and learning deficits, which are known as septic encephalopathy (SE). SE also includes behavioral changes. The underlying mechanism of SE is unknown, and several mechanisms have been proposed. This study investigated late anxiety-like behavior, serum cytokine levels and brain cytokine production in C57BL/6 mice subjected to polymicrobial sepsis induced by sublethal cecum ligature and puncture (CLP). Anxiety-like behavior and locomotor activity were assessed in mice 10 days after sham operation or CLP procedure using the elevated plus maze, contextual fear conditioning, and open field test. Brain and serum concentrations of the cytokines TNF-α, IFN-γ, IL-1β, IL-6, and IL-10 were determined by ELISA. We found that mice subjected to polymicrobial sepsis presented anxiety-like behavior, which was accompanied by increased serum TNF-α and brain TNF-α, IFN-γ, IL-1β, and IL-6 levels, 10 days after the surgical procedure. These findings suggest an involvement of central nervous system inflammatory mediators in the anxiety-like symptoms found in SE.
Neurotoxicity Research 12/2012; 24(2). DOI:10.1007/s12640-012-9364-1 · 3.15 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Dengue virus is a human pathogen that may cause meningoencephalitis and other neurological syndromes. The current study investigated anxiety-like behavior and expression of proinflammatory cytokines and pro-apoptotic caspase-3 in the hippocampus of C57BL/6 mice infected with non-adapted Dengue virus 3 genotype I (DENV-3) inoculated intracranially with 4×10(3) (plaque-forming unit) PFU. Anxiety-like behavior was assessed in control and DENV-3 infected mice using the elevated plus maze. The open field test was performed to evaluate locomotor activity. Histopathological changes in CA regions of the hippocampus were assessed by haematoxylin and eosin staining. Immunoreactive and protein levels of cleaved caspase-3 were also analyzed in the hippocampus. The mRNA expression of IL-6 and TNF-α in the hippocampus were estimated by quantitative real time (polymerase chain reaction) PCR. All procedures were conducted on day 5 post-infection. We found that DENV-3 infected mice presented higher levels of anxiety in comparison with controls (p≤0.05). No difference in motor activity was found between groups (p=0.77). The infection was followed by a significant increase of TNF-α and IL-6 mRNA expression in the hippocampus (p≤0.05). Histological analysis demonstrated meningoencephalitis with formation of perivascular cuffs, infiltration of immune cells and loss of neurons at CA regions of hippocampus. Numerous caspase-3 positive neurons were visualized at CA areas in DENV-3 infected mice. Marked increase of cleaved caspase-3 levels were observed after infection. This study described anxiety-like behavior, hippocampal inflammation and neuronal apoptosis associated with DENV-3 infection in the central nervous system.
Behavioural brain research 02/2012; 230(1):237-42. DOI:10.1016/j.bbr.2012.02.020 · 3.39 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective of the present study was to determine if there is a relationship between serum levels of brain-derived neurotrophic factor (BDNF) and the number of T2/fluid-attenuated inversion recovery (T2/FLAIR) lesions in multiple sclerosis (MS). The use of magnetic resonance imaging (MRI) has revolutionized the study of MS. However, MRI has limitations and the use of other biomarkers such as BDNF may be useful for the clinical assessment and the study of the disease. Serum was obtained from 28 MS patients, 18-50 years old (median 38), 21 women, 0.5-10 years (median 5) of disease duration, EDSS 1-4 (median 1.5) and 28 healthy controls, 19-49 years old (median 33), 19 women. BDNF levels were measured by ELISA. T1, T2/FLAIR and gadolinium-enhanced lesions were measured by a trained radiologist. BDNF was reduced in MS patients (median [range] pg/mL; 1160 [352.6-2640]) compared to healthy controls (1640 [632.4-4268]; P = 0.03, Mann-Whitney test) and was negatively correlated (Spearman correlation test, r = -0.41; P = 0.02) with T2/FLAIR (11-81 lesions, median 42). We found that serum BDNF levels were inversely correlated with the number of T2/FLAIR lesions in patients with MS. BDNF may be a promising biomarker of MS.
Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas / Sociedade Brasileira de Biofisica ... [et al.] 12/2011; 45(1):68-71. DOI:10.1590/S0100-879X2011007500165 · 1.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Multiple sclerosis is a neuroinflammatory disease that results in serious neurological disability. Besides physical impairment, behavioral symptoms are also common in patients with multiple sclerosis. Experimental autoimmune encephalomyelitis (EAE) is considered to be a model of multiple sclerosis and mimics the main features of the disease, such as demyelination and motor impairment. In this work, we aimed to study behavioral parameters in animals with EAE using the MOG(35-55) model in C57BL/6 mice. We analyzed memory and anxiety in animals using the elevated plus maze, the step down inhibitory avoidance task and the memory recognition test. No differences in any tests were found when comparing controls and animals induced with EAE. Therefore, we conclude that behavioral changes in animals with EAE induced with MOG(35-55) are probably subtle or absent.
Arquivos de neuro-psiquiatria 12/2011; 69(6):938-42. DOI:10.1590/S0004-282X2011000700018 · 1.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cerebral malaria is a severe form of the disease that may result, in part, from an overt inflammatory response during infection by Plasmodium falciparum. The understanding of the pathogenesis of cerebral malaria may aid in the development of better therapeutic strategies for patients. The immune response in cerebral malaria involves elevation of circulating levels of cytokines and chemokines associated with leukocyte accumulation and breakdown of the blood-brain barrier in the central nervous system. Platelet-activating factor (PAF) is a mediator of inflammation shown to orchestrate inflammatory processes, including recruitment of leukocytes and increase of vascular permeability. Using mice lacking the PAF receptor (PAFR(-/-)), we investigated the relevance of this molecule for the outcome and the neuroinflammatory process triggered by P. berghei ANKA, an experimental model of cerebral malaria. In PAFR(-/-) mice, lethality was markedly delayed and brain inflammation was significantly reduced, as demonstrated by histology, accumulation, and activation of CD8(+) T cells, changes in vascular permeability and activation of caspase-3 on endothelial cells and leukocytes. Similarly, treatment with the PAFR antagonist UK-74,505 delayed lethality. Taken together, the results suggest that PAFR signaling is crucial for the development of experimental cerebral malaria. Mechanistically, PAFR activation is crucial for the cascade of events leading to changes in vascular permeability, accumulation, and activation of CD8(+) T cells and apoptosis of leukocytes and endothelial cells.
American Journal Of Pathology 11/2011; 180(1):246-55. DOI:10.1016/j.ajpath.2011.09.038 · 4.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Herpes simplex virus-1 (HSV-1) is a pathogen that may cause severe encephalitis in humans. In this study, we aimed to investigate the role of interleukin-4 (IL-4) in a model of HSV-1 brain infection. IL-4 knockout (IL-4-/-) and wild type (WT) C57BL/6 mice were inoculated with 10(4) plaque-forming units of HSV-1 by the intracranial route. Histopathologic analysis revealed a distinct profile of infiltrating cells at 3 days post-infection (dpi). Infected WT mice presented mononuclear inflammatory cells while IL-4-/- mice developed meningoencephalitis with predominance of neutrophils. IL-4-/- mice had diminished leukocyte adhesion at 3 dpi when compared to infected WT animals in intravital microscopy study. Conversely no differences were found in cerebral levels of CXCL1, CXCL9, CCL3, CCL5 and TNF-α between WT and IL-4-/- infected mice. IL-4 may play a role in the recruitment of cells into central nervous system in this acute model of severe encephalitis caused by HSV-1.
Arquivos de neuro-psiquiatria 04/2011; 69(2A):237-41. DOI:10.1590/S0004-282X2011000200019 · 1.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cerebral malaria (CM) is a severe complication resulting from Plasmodium falciparum infection. The underlying mechanisms of CM pathogenesis remain incompletely understood. The imbalance between the release of proinflammatory and anti-inflammatory cytokines has been associated with central nervous system dysfunction found in human and experimental CM. The current study investigated anxiety-like behavior, histopathological changes and release of brain cytokines in C57BL/6 mice infected with Plasmodium berghei strain ANKA (PbA). Anxiety-like behavior was assessed in control and PbA-infected mice using the elevated plus maze test. Histopathological changes in brain tissue were assessed by haematoxylin and eosin staining. Brain concentration of the cytokines IL-1β, IL-4, IL-10, TNF-α and IFN-γ was determined by ELISA. We found that PbA-infected mice on day 5 post-infection presented anxiety symptoms, histopathological alterations in the brainstem, cerebrum and hippocampus and increased cerebral levels of proinflammatory cytokines IL-1β and TNF-α. These findings suggest an involvement of central nervous system inflammatory mediators in anxiety symptoms found in CM.
[Show abstract][Hide abstract] ABSTRACT: Dengue, one of the most important arboviral diseases of humans, may cause severe systemic disease. Although dengue virus (DENV) has been considered to be a non-neurotropic virus, dengue infection has been associated recently with a series of neurological syndromes, including encephalitis. In this work, we evaluated behavioral changes and inflammatory parameters in C57BL/6 mice infected with non-adapted dengue virus 3 (DENV-3) genotype I.
C57BL/6 mice received 4×10(3) PFU of DENV-3 by an intracranial route. We evaluated the trafficking of leukocytes in brain microvasculature using intravital microscopy, and evaluated chemokine and cytokine profiling by an ELISA test at 3 and 6 days post infection (p.i.). Furthermore, we determined myeloperoxidase activity and immune cell populations, and also performed histopathological analysis and immunostaining for the virus in brain tissue.
All animals developed signs of encephalitis and died by day 8 p.i. Motor behavior and muscle tone and strength parameters declined at day 7 p.i. We observed increased leukocyte rolling and adhesion in brain microvasculature of infected mice at days 3 and 6 p.i. The infection was followed by significant increases in IFN-γ, TNF-α, CCL2, CCL5, CXCL1, and CXCL2. Histological analysis showed evidence of meningoencephalitis and reactive gliosis. Increased numbers of neutrophils, CD4+ and CD8+ T cells were detected in brain of infected animals, notably at day 6 p.i. Cells immunoreactive for anti-NS-3 were visualized throughout the brain.
Intracerebral infection with non-adapted DENV-3 induces encephalitis and behavioral changes that precede lethality in mice.
Journal of Neuroinflammation 03/2011; 8(1):23. DOI:10.1186/1742-2094-8-23 · 4.90 Impact Factor