Publications (24)80.13 Total impact
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Article: Increase in Th17 and T-reg lymphocytes and decrease of IL22 correlate with the recovery phase of acute EAE in rat.
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ABSTRACT: Experimental autoimmune encephalomyelitis (EAE), a well-established model of multiple sclerosis, is characterised by microglial activation and lymphocyte infiltration. Induction of EAE in Lewis rats produces an acute monophasic disease characterised by a single peak of disability followed by a spontaneous and complete recovery and a subsequent tolerance to further immunizations. In the current study we have performed a detailed analysis of the dynamics of different lymphocyte populations and cytokine profile along the induction, peak, recovery and post-recovery phases in this paradigm. MBP-injected rats were sacrificed attending exclusively to their clinical score, and the different populations of T-lymphocytes as well as the dynamics of different pro- and anti-inflammatory cytokines were analysed in the spinal cord by flow cytometry, immunohistochemistry and ELISA. Our results revealed that, during the induction and peak phases, in parallel to an increase in symptomatology, the number of CD3+ and CD4+ cells increased progressively, showing a Th1 phenotype, but unexpectedly during recovery, although clinical signs progressively decreased, the number and proportion of CD3+ and CD4+ populations remained unaltered. Interestingly, during this recovery phase, we observed a marked decrease of Th1 and an important increase in Th17 and T-reg cells. Moreover, our results indicate a specific cytokine expression profile along the EAE course characterized by no changes of IL10 and IL17 levels, decrease of IL21 on the peak, and high IL22 levels during the induction and peak phases that markedly decrease during recovery. In summary, these results revealed the existence of a specific pattern of lymphocyte infiltration and cytokine secretion along the different phases of the acute EAE model in Lewis rat that differs from those already described in chronic or relapsing-remitting mouse models, where Th17-cells were found mostly during the peak, suggesting a specific role of these lymphocytes and cytokines in the evolution of this acute EAE model.PLoS ONE 01/2011; 6(11):e27473. · 4.09 Impact Factor -
Article: Activated microglial cells acquire an immature dendritic cell phenotype and may terminate the immune response in an acute model of EAE.
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ABSTRACT: Antigen presentation, a key mechanism in immune responses, involves two main signals: the first is provided by the engagement of a major histocompatibility complex (MHC), class I or class II, with their TCR receptor in lymphocytes, whereas the second demands the participation of different co-stimulatory molecules, such as CD28, CTLA-4 and their receptors B7.1 and B7.2. Specific T-cell activation and deactivation are achieved through this signalling. The aim of our study is to characterise, in the acute experimental autoimmune encephalomyelitis (EAE) model in Lewis rat, the temporal expression pattern of these molecules as well as the cells responsible for their expression. To accomplish that, MBP-immunised female Lewis rats were daily examined for the presence of clinical symptoms and sacrificed, according to their clinical score, at different phases during EAE. Spinal cords were cut with a cryostat and processed for immunohistochemistry: MHC-class I and MHC-class II, co-stimulatory molecules (B7.1, B7.2, CD28, CTLA-4) and markers of dendritic cells (CD1 for immature cells and fascin for mature cells). Our results show that microglial cells are activated in the inductive phase and, during this phase and peak, they are able to express MHC-class I, MHC-class II and CD1, but not B7.1 and B7.2. This microglial phenotype may induce the apoptosis or anergy of infiltrated CD28+ lymphocytes observed around blood vessels and in the parenchyma. During the recovery phase, microglial cells express high MHC-class I and class II and, those located in the surroundings of blood vessels, displayed the B7.2 co-stimulatory molecule. These cells are competent to interact with CTLA-4+ cells, which indicate an active role of microglial cells in modulating the ending of the immune response by inducing lymphocyte activity inhibition and Treg activation. Once clinical symptomatology disappeared, some foci of activated microglial cells (MHC-class II+/B7.2+) were still present in concomitance with CTLA-4+ cells, suggesting a prolonged involvement of microglia in lymphocyte inhibition and tolerance promotion. In addition to microglia, during the inductive and recovery phases, we also found perivascular ED2+ cells and fascin+ cells which are able to migrate to the parenchyma and may play a role in lymphocytic regulation. Further studies to understand the specific function played by these cells are warranted.Journal of neuroimmunology 06/2010; 223(1-2):39-54. · 2.84 Impact Factor -
Article: Immunotoxic depletion of microglia in mouse hippocampal slice cultures enhances ischemia-like neurodegeneration.
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ABSTRACT: Microglial cells have been attributed both neuroprotective and neurodegenerative roles in cerebral ischemia. This study presents an immunotoxic method for depletion of microglia from mouse hippocampal slice cultures and the effect of this on ischemia-like oxygen-glucose deprivation (OGD). For microglial depletion hippocampal slice cultures were exposed for 7 days to saporin coupled to an antibody against the microglial receptor Mac1 (Mac1-sap). When subjected to OGD immediately thereafter, resulting neurodegeneration was quantified as cellular uptake of propidium iodide (PI). Cultures were processed 1, 7 or 14 days after OGD for general cell staining and immunohistochemistry for neuronal, astroglial and microglial markers. Following Mac1-sap treatment there was a near total loss of microglia, these microglia-depleted cultures displayed a significant increase in PI uptake and astrogliosis 1 day after OGD compared to non-depleted cultures. In cultures surviving 7 and 14 days after OGD there was a decrease in PI uptake compared to 1 day after OGD. At 7 and 14 days after OGD the differences in Mac1-sap treated or non-treated cultures were still noticeable in terms of more neuron loss in cultures deprived of microglia, while the astroglial reactivity seemed to equalize. Based on the finding that depletion of microglia significantly increased OGD-induced CA1 pyramidal cell degeneration, we conclude that microglia at least in the initial phase of injury exert a neuroprotective role in mouse hippocampal slice cultures.Brain research 08/2009; 1291:140-52. · 2.46 Impact Factor -
Article: Neuroprotective effects of the anti-inflammatory compound triflusal on ischemia-like neurodegeneration in mouse hippocampal slice cultures occur independent of microglia.
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ABSTRACT: Microglial cells, known to play key roles in neuroinflammation, can be immunotoxically eliminated from hippocampal slice cultures by treatment with saporin coupled to the microglial receptor Mac1. Considering microglial cells as a target for anti-inflammatory treatment we studied the effects of microglial depletion on anti-inflammatory treatment of mouse hippocampal slice cultures subjected to ischemia-like neurodegeneration, induced by oxygen-glucose deprivation (OGD). Hippocampal slice cultures, derived from 7-day-old mice and grown for 2 weeks, were divided into 8 groups: (1) control cultures; (2) sham-OGD cultures; (3) OGD cultures; (4) OGD cultures treated with triflusal during OGD; (5) microglia-depleted control cultures; (6) microglia-depleted sham-OGD cultures; (7) microglia-depleted OGD cultures; and (8) microglia-depleted OGD cultures treated with triflusal during OGD. The resulting neurodegeneration was quantified by densitometric measurements of cellular uptake of propidium iodide (PI), with focus on the hippocampal CA1 subfield. Subjection of regular cultures to OGD for 30 min induced a significant increase in PI uptake in the CA1 pyramidal cell layer, compared to control cultures. The presence of 100 microM triflusal during OGD protected against OGD-induced neurodegeneration, and reduced the number of OGD-induced NFkB positive-cells correspondingly. Cultures treated with the Mac1-saporin complex for 7 days displayed an almost total loss of microglial cells. When subjected to OGD after microglial depletion, these cultures displayed a significant increase in OGD-induced PI uptake compared to non-depleted cultures. The presence of triflusal during OGD of these cultures reduced neurodegeneration of the irrespective absence of microglia. In accordance with that, the presence of triflusal during OGD significantly inhibited the increase in the number of reactive microglia and proliferative cells in the CA1 pyramidal and dentate granule cell layers. We conclude that immunotoxic microglia depletion significantly increases the susceptibility of CA1 pyramidal cells to neurodegeneration and that the anti-inflammatory drug triflusal still can exert its neuroprotective role following depletion of microglia.Experimental Neurology 04/2009; 218(1):11-23. · 4.70 Impact Factor -
Article: CD4 microglial expression correlates with spontaneous clinical improvement in the acute Lewis rat EAE model.
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ABSTRACT: CD4 is a molecule commonly expressed on the surface of T-helper lymphocytes with a recognized critical role in the antigen presentation process that has also been reported in monocytes and macrophages, although its role in these cells remains unknown. The objective of the present study was to analyze whether experimental conditions involving a potent acquired immune component, as occurs in experimental autoimmune encephalomyelitis (EAE), are able to induce CD4 expression in the population of microglia/macrophages. Myelin Basic Protein (MBP) immunized female Lewis rats, were examined at different phases during the course of EAE according to their clinical score. Spinal cords were analyzed by flow cytometry for CD11b, CD4 and CD45, by histochemistry for NDPase and by immunohistochemistry for ED2, Iba1, CD45 and CD4. Flow cytometry analysis showed that EAE induced CD4 expression in macrophages (CD11b+/CD45(high)) and microglia (in both CD11b+/CD45(intermediate) and CD11b+/CD45(low) phenotypes). Noticeably, microglial CD4 expression was found during the recovery phase and was maintained until 40 days post-induction. In agreement, immunolabelled sections revealed CD4 expression in microglial cells with ramified morphology during the recovery and post-recovery phases. In conclusion, our results indicate that, in this EAE model, perivascular cells, microglia and macrophages showed different dynamics during the course of the disease in close relation with symptomatology and that microglial cells expressed CD4 interestingly during the recovery phase, suggesting a role of microglial CD4 expression in the resolution of the immune response.Journal of neuroimmunology 03/2009; 209(1-2):65-80. · 2.84 Impact Factor -
Article: RGD domains neuroprotect the immature brain by a glial-dependent mechanism.
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ABSTRACT: Integrin binding to extracellular matrix ligands, including those presenting RGD motifs, modulate diverse cellular processes. In the brain, many endogenous RGD-containing molecules are induced after damage. Previously, the gene therapy vector termed NLSCt, which displays an RGD motif, was shown to neuroprotect after immature brain excitotoxicity. We analyze whether neuroprotection is mediated by the RGD motif. RGD-containing synthetic peptide GPenGRGDSPCA (GPen) was injected 2 hours after N-methyl-D-aspartate-mediated excitotoxicity to the postnatal day 9 rat brain. Damage and glial/inflammatory response were evaluated 3 days later. In addition, the neuroprotective effect of GPen and NLSCt after N-methyl-D-aspartate-induced cell death was also analyzed in vitro using neuron-purified and mixed neuron-glia primary cultures. To further characterize whether the neuroprotective effect was mediated by glial-derived soluble factors, we also tested the protective ability of conditioned media from RGD-treated microglia, astrocyte, or mixed glia cultures. Animals treated with GPen peptide showed functional improvement, a significant reduction in lesion volume up to 28%, and a decrease in the number of degenerating neurons. In addition, N-methyl-D-aspartate-injected animals treated with both RGD-containing molecules at the neuroprotective doses showed a significant increase in microglial reactivity and microglia/macrophage cell number, but no differences in neutrophil infiltration and the astroglial response. Finally, in vitro studies showed that the neuroprotective effect was observed in mixed neuron-glia, but not in neuron-purified cultures. Conditioned media from RGD-treated microglial, astroglial, and mixed-glial cultures were not protective. These results suggest that RGD-containing molecules neuroprotect by a glial-dependent mechanism.Annals of Neurology 10/2007; 62(3):251-61. · 11.09 Impact Factor -
Article: Caspase-3 activation in astrocytes following postnatal excitotoxic damage correlates with cytoskeletal remodeling but not with cell death or proliferation.
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ABSTRACT: Caspase-3 has classically been defined as the main executioner of programmed cell death. However, recent data supports the participation of this protease in non-apoptotic cellular events including cell proliferation, cell cycle regulation, and cellular differentiation. In this study, astroglial cleavage of caspase-3 was analyzed following excitotoxic damage in postnatal rats to determine if its presence is associated with apoptotic cell death, cell proliferation, or cytoskeletal remodeling. A well-characterized in vivo model of excitotoxicity was studied, where damage was induced by intracortical injection of N-methyl-D-asparate (NMDA) in postnatal day 9 rats. Our results demonstrate that cleaved caspase-3 was mainly observed in the nucleus of activated astrocytes in the lesioned hemisphere as early as 4 h postlesion and persisted until the glial scar was formed at 7-14 days, and it was not associated with TUNEL labeling. Caspase-3 enzymatic activity was detected at 10 h and 1 day postlesion in astrocytes, and co-localized with caspase-cleaved fragments of glial fibrillary acidic protein (CCP-GFAP). However, at longer survival times, when astroglial hypertrophy was observed, astroglial caspase-3 did not generally correlate with GFAP cleavage, but instead was associated with de novo expression of vimentin. Moreover, astroglial caspase-3 cleavage was not associated with BrdU incorporation. These results provide further evidence for a nontraditional role of caspases in cellular function that is independent of cell death and suggest that caspase activation is important for astroglial cytoskeleton remodeling following cellular injury.Glia 08/2007; 55(9):954-65. · 4.82 Impact Factor -
Article: Antioxidant Cu/Zn SOD: expression in postnatal brain progenitor cells.
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ABSTRACT: Precursor cells have been shown to be affected by oxidative stress, in vivo and vitro, but little is known about the expression of antioxidant mechanisms in neuronal/glial differentiation. We have characterized the expression of Cu/Zn superoxide dismutase (Cu/Zn SOD), one of the main antioxidant proteins involved in the breakdown of superoxide, in the immature rat dorsolateral subventricular zone (SVZ), rostral migratory stream (RMS) and hippocampal subgranular zone (SGZ). Progenitor cells were identified immunohistochemically on cryostat sections by 5'Bromodeoxyuridine (BrdU) incorporation and expressing cells were further characterized using double labeling for progenitor markers. In the SVZ, only a subpopulation of BrdU+ cells, mostly found in the medial SVZ, expressed Cu/Zn SOD. These cells were mostly nestin+ and some were also vimentin+. In contrast, in the lateral SVZ few Cu/Zn SOD+/BrdU+ cells were found. These were primarily nestin+, vimentin-, showed some PSA-NCAM expression, but only a few were NG2+. In the RMS and SGZ virtually all BrdU+ progenitors were Cu/Zn SOD+ and expressed nestin and vimentin. Some RMS cells were also PSA-NCAM+. These findings show a heterogeneous expression of Cu/Zn SOD in restricted cell types in the germinative zones and suggest a role for antioxidant Cu/Zn SOD in progenitor cells of the immature rat brain.Neuroscience Letters 07/2006; 401(1-2):71-6. · 2.11 Impact Factor -
Article: Neuroprotection from NMDA excitotoxic lesion by Cu/Zn superoxide dismutase gene delivery to the postnatal rat brain by a modular protein vector.
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ABSTRACT: Superoxide mediated oxidative stress is a key neuropathologic mechanism in acute central nervous system injuries. We have analyzed the neuroprotective efficacy of the transient overexpression of antioxidant enzyme Cu/Zn Superoxide dismutase (SOD) after excitotoxic injury to the immature rat brain by using a recently constructed modular protein vector for non-viral gene delivery termed NLSCt. For this purpose, animals were injected with the NLSCt vector carrying the Cu/Zn SOD or the control GFP transgenes 2 hours after intracortical N-methyl-D-aspartate (NMDA) administration, and daily functional evaluation was performed. Moreover, 3 days after, lesion volume, neuronal degeneration and nitrotyrosine immunoreactivity were evaluated. Overexpression of Cu/Zn SOD transgene after NMDA administration showed improved functional outcome and a reduced lesion volume at 3 days post lesion. In secondary degenerative areas, increased neuronal survival as well as decreased numbers of degenerating neurons and nitrotyrosine immunoreactivity was seen. Interestingly, injection of the NLSCt vector carrying the control GFP transgene also displayed a significant neuroprotective effect but less pronounced. When the appropriate levels of Cu/Zn SOD are expressed transiently after injury using the non-viral modular protein vector NLSCt a neuroprotective effect is seen. Thus recombinant modular protein vectors may be suitable for in vivo gene therapy, and Cu/Zn SOD should be considered as an interesting therapeutic transgene.BMC Neuroscience 02/2006; 7:35. · 3.04 Impact Factor -
Article: Astroglial nitration after postnatal excitotoxic damage: correlation with nitric oxide sources, cytoskeletal, apoptotic and antioxidant proteins.
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ABSTRACT: Oxygen free radicals and nitric oxide (NO) participate in the pathogenesis of acute central nervous system (CNS) injury by forming peroxynitrite, which promotes oxidative damage and tyrosine nitration. Neuronal nitration is associated with cell death, but little is known of the characteristics and cell fate of nitrated astrocytes. In this study, we have used a postnatal excitotoxic lesion model (intracortical NMDA injection) and our aims were (i) to evaluate the temporal and spatial pattern of astroglial nitration in correlation with the neuropathological process and the sources of NO; and (ii) to establish, if any, the correlation among astrocyte nitration and other events such as expression of cytoskeletal proteins, antioxidant enzymes, and cell death markers to cope with nitration and/or undergo cell death. Our results show that after postnatal excitotoxic damage two distinct waves of nitration were observed in relation to astrocytes. At 24 h post-lesion, early-nitrated astrocytes were found within the neurodegenerating area, coinciding with the time of maximal cell death. These early-nitrated astrocytes are highly ramified protoplasmic cells, showing diffuse glial fibrillary acidic protein (GFAP) content and expressing inducible NOS. At later time-points, when astrogliosis is morphologically evident, nitrated hypertrophied reactive astrocytes are observed in the penumbra and the neurodegenerated area, displaying increased expression of GFAP and vimentin cytoskeletal proteins and of metallothionein I-II and Cu/Zn superoxide dismutase antioxidant proteins. Moreover, despite revealing activated caspase-3, they do not show TUNEL labeling. In summary, we show that nitrated astrocytes in vivo constitute a subpopulation of highly reactive astrocytes which display high resistance towards oxidative stress induced cell death.Journal of Neurotrauma 02/2005; 22(1):189-200. · 3.65 Impact Factor -
Article: Dynamics of microglia in the developing rat brain.
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ABSTRACT: Entrance of mesodermal precursors into the developing CNS is the most well-accepted origin of microglia. However, the contribution of proliferation and death of recruited microglial precursors to the final microglial cell population remains to be elucidated. To investigate microglial proliferation and apoptosis during development, we combined proliferating cell nuclear antigen (PCNA) immunohistochemistry, in situ detection of nuclear DNA fragmentation (TUNEL), and caspase-3 immunohistochemistry with tomato lectin histochemistry, a selective microglial marker. The study was carried out in Wistar rats from embryonic day (E) 16 to postnatal day (P) 18 in cerebral cortex, subcortical white matter, and hippocampus. Proliferating microglial cells were found at all ages in the three brain regions and represented a significant fraction of the total microglial cell population. The percentage of microglia expressing PCNA progressively increased from the embryonic period (25-51% at E16) to a maximum at P9, when the great majority of microglia expressed PCNA (92-99%) in all the brain regions analyzed. In spite of the remarkable proliferation and expansion of the microglial population with time, the density of microglia remained quite constant in most brain regions because of the considerable growth of the brain during late prenatal and early postnatal periods. In contrast, apoptosis of microglia was detected only at certain times and was restricted to some ameboid cells in white matter and primitive ramified cells in gray matter, representing a small fraction of the microglial population. Therefore, our results point to proliferation of microglial precursors in the developing brain as a physiological mechanism contributing to the acquisition of the adult microglial cell population. In contrast, microglial apoptosis occurs only locally at certain developmental stages and thus seems less crucial for the establishment of the final density of microglia.The Journal of Comparative Neurology 04/2003; 458(2):144-57. · 3.81 Impact Factor -
Article: Time course of proliferation and elimination of microglia/macrophages in different neurodegenerative conditions.
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ABSTRACT: Ablation of the hindlimb area of the sensorimotor cortex produces degeneration in the cortex (invasive traumatic injury) and leads to retrograde and/or anterograde degeneration in the thalamus (non-invasive injury, distal reaction). This provides an useful model to study the proliferation and elimination of microglia/macrophages in different neurodegenerative conditions. Changes in the morphology, distribution and numbers of microglia in the affected cortex and thalamus were analyzed at various time points (12 h to 30 days) after injury. In parallel, proliferation was determined by immunocytochemistry for the proliferating cell nuclear antigen and cell death by the TUNEL method. Proliferation was an early event in the microglia/macrophage response (from 12 h in the cortex and from 2 days post-lesion in the thalamus) and persisted up to 30 days. The different microglia/macrophage phenotypes proliferated in a specific temporospatial pattern. In the lesioned cortex, early activation and proliferation of intrinsic microglia was accompanied, from the second post-lesion day, by monocyte entrance and proliferation of monocyte-derived cells. In contrast, accumulation of cells in the thalamus resulted from proliferation of intrinsic microglia, without apparent/significant monocytic recruitment. During the subsequent microglia/macrophages removal the majority of the cells in the cortex transformed into ameboid cells devoid of cell processes that progressively accumulated as fully-developed macrophages tissue within the lesion (3-14 days) ultimately migrating out to the meningeal connective tissue (14-30 days). Only some process-bearing cells, remaining in the cortical tissue bordering the lesion, underwent degeneration by 14-21 days post-lesion. In contrast, in the distal affected thalamic nuclei, microglial cell death occurred by 14-30 days post-lesion. Altogether, this study shows that both the origin and fate of microglia/macrophages depend on the nature of the lesion.Journal of Neurotrauma 12/2002; 19(11):1503-20. · 3.65 Impact Factor -
Article: Decrease of proinflammatory molecules correlates with neuroprotective effect of the fluorinated salicylate triflusal after postnatal excitotoxic damage.
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ABSTRACT: The fluorinated salicylate triflusal has been shown to have a neuroprotective effect after an excitotoxic lesion to the postnatal brain. In this regard, the aim of this study was to elucidate whether neuroprotection was associated with changes in the expression of proinflammatory molecules such as interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), inducible nitric oxide synthase (iNOS), or cyclooxygenase-2 (COX-2), well-known mediators of oxidative stress and inflammation, mechanisms underlying secondary damage occurring after excitotoxic/ischemic brain injury. Postnatal day 9 rats received an intracortical injection of N-methyl-D-aspartate followed by oral administration of triflusal (30 mg/kg) 8 hours later. Ten or 24 hours after lesion, animals were killed, and brain sections processed for the immunohistochemical demonstration of IL-1beta, TNF-alpha, iNOS, and COX-2. Besides a reduction in the neurodegenerative area, triflusal strongly decreased iNOS immunolabeling at both survival times analyzed, attenuating iNOS immunoreactivity in astroglial cells and infiltrated neutrophils. Additionally, a moderate reduction in COX-2, IL-1beta, and TNF-alpha was observed. Triflusal decreased neuronal and microglial COX-2 expression at 10 and 24 hours after lesion and microglial and astroglial expression of IL-1beta and TNF-alpha at 24 hours after lesion. TNF-alpha expression in neuronal cells at 10 hours after lesion was, however, maintained. This study suggests that triflusal neuroprotection is associated with a decrease of iNOS and other inflammatory mediators and therefore may constitute a good therapeutic agent in pathological situations in which regulation of inflammatory genes constitutes a relevant step in the outcome of the neurodegenerative event.Stroke 11/2002; 33(10):2499-505. · 5.73 Impact Factor -
Article: Expression of inducible nitric oxide synthase and cyclooxygenase-2 after excitotoxic damage to the immature rat brain.
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ABSTRACT: It is well established that after adult brain damage the enzymes cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) play an important role in the inflammatory processes and oxidative stress, which are considered to be the leading factors contributing to delayed cell death. The contribution of these enzymes to postnatal brain damage, however, is poorly understood. In our study, excitotoxic lesions were induced by the injection of N-methyl-D-aspartate in the cortex of postnatal day 9 rats. After different survival times ranging from 4 hr to 7 days post-lesion, brain sections were processed for the immunocytochemical demonstration of COX-2 and iNOS and double labeling with neuronal, glial and neutrophil markers. First and maximal de novo induction of iNOS and COX-2 expression was found at 10 hr post-lesion. Expression of both enzymes started to diminish at 24 hr, reaching basal levels at day 3. iNOS-expressing cells were mainly identified as infiltrated neutrophils as well as highly ramified protoplasmic astrocytes closely associated with blood vessels. Moreover, scattered iNOS-positive neurons were found at the lesion borders. In contrast, COX-2 was mainly observed in reactive microglial cells and neuronal cells. COX-2-positive neurons were found within the degenerating area at 10 hr and at the borders of the lesion later on. This study shows that maximal iNOS and COX-2 expression precedes the period of massive neuronal death observed at 24 hr post-lesion, and may therefore contribute to the evolution of the inflammatory response and the neurodegenerative process after an excitotoxic lesion to the postnatal brain.Journal of Neuroscience Research 07/2002; 68(6):745-54. · 2.74 Impact Factor -
Article: Glial expression of small heat shock proteins following an excitotoxic lesion in the immature rat brain.
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ABSTRACT: Heat shock proteins (HSPs) are chaperones induced under pathological conditions and involved in protein stabilization and cellular protection. In this study, we have evaluated the expression pattern of the glial cell-related HSP27, HSP32, and HSP47 following an excitotoxic lesion in the immature rat brain. Postnatal day 9 rats received an intracortical injection of N-methyl-D-aspartate and tissue was processed immunohistochemically for HSPs and double labeling using astroglial and microglial markers. HSP expression was quantified by image analysis. Excitotoxic damage caused primary cortical degeneration and secondary damage in the corresponding thalamus. In the injured cortex, reactive microglia/macrophages expressed HSP32 from 10 h until 14 days postlesion (PL), showing maximal levels at days 3-5. In parallel, most cortical reactive astrocytes showed expression of HSP47 from 10 h until 14 days PL and a population of them also displayed HSP27 labeling from 1 day PL. In addition, some cortical reactive astrocytes showed a temporary expression of HSP32 at day 1. In general, astroglial HSP expression in the cortex achieved maximal levels at days 3-5 PL. In the damaged thalamus, HSP32 was not significantly induced, but reactive astrocytes expressed HSP47 and some of them also HSP27. Thalamic astroglial HSP induction was transient, peaked at 5 days PL and reached basal levels by day 14. The injury-induced expression of HSP32, HSP27, and HSP47 in glial cells may contribute to glial cell protection and adaptation to damage, therefore playing an important role in the evolution of the glial response and the excitotoxic lesion outcome. HSP32 may provide antioxidant protective mechanisms to microglia/macrophages, whereas HSP47 could contribute to extracellular matrix remodeling and HSP27 may stabilize the astroglial cytoskeleton and participate in astroglial antioxidant mechanisms.Glia 05/2002; 38(1):1-14. · 4.82 Impact Factor -
Article: NF-kappaB and IkappaBalpha expression following traumatic brain injury to the immature rat brain.
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ABSTRACT: NF-kappaB is one of the most important modulators of stress and inflammatory gene expression in the nervous system. In the adult brain, NF-kappaB upregulation has been demonstrated in neurons and glial cells in response to experimental injury and neuropathological disorders, where it has been related to both neurodegenerative and neuroprotective activities. Accordingly, the aim of this study was to evaluate the cellular and temporal patterns of NF-kappaB activation and the expression of its endogenous inhibitor IkappaBalpha following traumatic brain injury (TBI) during the early postnatal weeks, when the brain presents elevated levels of plasticity and neuroprotection. Our results showed that cortical trauma to the 9-day-old rat brain induced a very fast upregulation of NF-kappaB, which was maximal within the first 24 hours after injury. NF-kappaB was mainly observed in neuronal cells of the degenerating cortex as well as in astrocytes located in the corpus callosum adjacent to the injury, where a pulse-like pattern of microglial NF-kappaB activation was also found. In addition, astrocytes of the corpus callosum, and microglial cells to a lower extent, also showed de novo expression of IkappaBalpha within the time of NF-kappaB activation. This study suggests an important role of NF-kappaB activation in the early mechanisms of neuronal death or survival, as well as in the development of the glial and inflammatory responses following traumatic injury to the immature rat brain.Journal of Neuroscience Research 04/2002; 67(6):772-80. · 2.74 Impact Factor -
Article: NF‐κB and IκBα expression following traumatic brain injury to the immature rat brain
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ABSTRACT: NF-κB is one of the most important modulators of stress and inflammatory gene expression in the nervous system. In the adult brain, NF-κB upregulation has been demonstrated in neurons and glial cells in response to experimental injury and neuropathological disorders, where it has been related to both neurodegenerative and neuroprotective activities. Accordingly, the aim of this study was to evaluate the cellular and temporal patterns of NF-κB activation and the expression of its endogenous inhibitor IκBα following traumatic brain injury (TBI) during the early postnatal weeks, when the brain presents elevated levels of plasticity and neuroprotection. Our results showed that cortical trauma to the 9-day-old rat brain induced a very fast upregulation of NF-κB, which was maximal within the first 24 hours after injury. NF-κB was mainly observed in neuronal cells of the degenerating cortex as well as in astrocytes located in the corpus callosum adjacent to the injury, where a pulse-like pattern of microglial NF-κB activation was also found. In addition, astrocytes of the corpus callosum, and microglial cells to a lower extent, also showed de novo expression of IκBα within the time of NF-κB activation. This study suggests an important role of NF-κB activation in the early mechanisms of neuronal death or survival, as well as in the development of the glial and inflammatory responses following traumatic injury to the immature rat brain. © 2002 Wiley-Liss, Inc.Journal of Neuroscience Research 03/2002; 67(6):772 - 780. · 2.74 Impact Factor -
Article: Expression of 27 kDa heat shock protein (Hsp27) in immature rat brain after a cortical aspiration lesion
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ABSTRACT: The 27 kDa heat shock protein (Hsp27) is a well-known member of the astroglial response to injury, playing a protective role against oxidative stress, apoptosis, and cytoskeletal destruction. Although several studies have been focused on the damaged adult brain, little is known about Hsp27 expression in the immature brain. In this work, we have examined the spatiotemporal pattern of Hsp27 expression in the normal postnatal rat brain following a cortical aspiration lesion at postnatal day 9. In the immature brain, Hsp27 is mainly observed in the internal capsule, although some scattered cells are also found in the ependyma, the corpus callosum, the septum, and hypothalamic glia limitans. In the internal capsule, Hsp27 expression is developmentally regulated, being significantly decreased from postnatal day 14. After a cortical aspiration lesion, de novo expression of Hsp27 is observed in cortical injured areas as well as in the secondary affected thalamus. In the cortex, expression of Hsp27 is first seen at day 1 postlesion (PL) surrounding the neurodegenerative area, becoming restricted to the glial scar at longer survival times. Although a pulse-like expression of Hsp27 is observed in some microglial cells at day 1 PL, most Hsp27-labeled cells are reactive astrocytes, which show GFAP overexpression and coexpress vimentin from day 3 PL. In the thalamus, astroglial Hsp27 expression is delayed, being first observed at day 5 PL. Thalamic Hsp27-labeled astrocytes do not show vimentin expression. Our observations demonstrate astroglial expression of Hsp27 in areas of tissue damage following postnatal traumatic injury, suggesting an involvement of this cytoskeleton-stabilizing protein in the remodeling processes following postnatal brain damage. GLIA 36:259–270, 2001. © 2001 Wiley-Liss, Inc.Glia 11/2001; 36(3):259 - 270. · 4.82 Impact Factor -
Article: Neuronal, astroglial and microglial cytokine expression after an excitotoxic lesion in the immature rat brain
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ABSTRACT: Cytokines are important intercellular messengers involved in neuron–glia interactions and in the microglial-astroglial crosstalk, modulating the glial response to brain injury and the lesion outcome. In this study, excitotoxic lesions were induced by the injection of N-methyl-d-aspartate in postnatal day 9 rats, and the cytokines interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumour necrosis factor alpha (TNF) and transforming growth factor beta 1 (TGF-β1) analysed by ELISA and/or immunohistochemistry. Moreover, cytokine-expressing glial cells were identified by means of double labelling with glial fibrillary acidic protein or tomato lectin binding. Our results show that both neurons and glia were capable of cytokine expression following different patterns in the excitotoxically damaged area vs. the nondegenerating surrounding grey matter (SGM). Excitotoxically damaged neurons showed upregulation of IL-6 and downregulation of TNF and TGF-β1 before they degenerated. Moreover, in the SGM, an increased expression of neuronal IL-6, TNF and TGF-β1 was observed. A subpopulation of microglial cells, located in the SGM and showing IL-1β and TNF expression, were the earliest glial cells producing cytokines, at 2–10 h postinjection. Later on, cytokine-positive glial cells were found within the excitotoxically damaged area and the adjacent white matter: some reactive astrocytes expressed TNF and IL-6, and microglia/macrophages showed mild IL-1β and TGF-β1. Finally, the expression of all cytokines was observed in the glial scar. As discussed, this pattern of cytokine production suggests their implication in the evolution of excitotoxic neuronal damage and the associated glial response.European Journal of Neuroscience 09/2000; 12(10):3505 - 3520. · 3.63 Impact Factor -
Article: Respuesta de estrés y efectos de la experiencia temprana: evidencia conductual, fisiológica y neuromorfológica
Ansiedad y estrés. 01/1998;
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1995–2011
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Autonomous University of Barcelona
- • Departamento de Biología Celular, Fisiología e Inmunología
- • Facultat de Medicina
- • Departamento de Medicina
Cerdanyola del Vallès, Catalonia, Spain
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2005
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University of Barcelona
- Departament de Medicina
Barcelona, Catalonia, Spain
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