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1دورية أكاديمية
المؤلفون: Pinto‐Benito, Daniel, Paradela‐Leal, Carmen, Ganchala, Danny, de Castro‐Molina, Paula, Arevalo, Maria‐Angeles
المساهمون: Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable, Ministerio de Ciencia e Innovación, Federación Española de Enfermedades Raras
المصدر: Glia ; volume 70, issue 6, page 1153-1169 ; ISSN 0894-1491 1098-1136
الوصف: Insulin‐like growth factor‐I (IGF‐I) signaling plays a key role in neuroinflammation. Here we show that IGF‐1 also regulates phagocytosis of reactive astrocytes through p110α isoform of phosphatidylinositol 3‐kinase (PI3K), differentially in both sexes. Systemic bacterial lipopolysaccharide (LPS)‐treatment increased the expression of GFAP, a reactive astrocyte marker, in the cortex of mice in both sexes and was blocked by IGF‐1 only in males. In primary astrocytes, LPS enhanced the mRNA expression of Toll‐like receptors (TLR2,4) and proinflammatory factors: inducible nitric oxide synthase (iNOS), chemokine interferon‐γ‐inducible protein‐10 (IP‐10) and cytokines (IL‐1β, IL‐6, and IL‐10) in male and female. Treatment with IGF‐1 counteracted TLR4 but not TLR2, iNOS, and IP10 expression in both sexes and cytokines expression in males. Furthermore, reactive astrocyte phagocytosis was modulated by IGF‐1 only in male astrocytes. IGF‐1 was also able to increase AKT‐phosphorylation only in male astrocytes. PI3K inhibitors, AG66, TGX‐221, and CAL‐101, with selectivity toward catalytic p110α, p110β, and p110δ isoforms respectively, reduced AKT‐phosphorylation in males. All isoforms interact physically with IGF‐1‐receptor in both sexes. However, the expression of p110α is higher in males while the expression of IGF‐1‐receptor is similar in male and female. AG66 suppressed the IGF‐1 effect on cytokine expression and counteracted the IGF‐1‐produced phagocytosis decrease in male reactive astrocytes. Results suggest that sex‐differences in the effect of IGF‐1 on the AKT‐phosphorylation could be due to a lower expression of the p110α in female and that IGF‐1‐effects on the inflammatory response and phagocytosis of male reactive astrocytes are mediated by p110α/PI3K subunit.
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2دورية أكاديمية
المؤلفون: Yanguas‐Casás, Natalia, Crespo‐Castrillo, Andrea, Arevalo, Maria‐Angeles, Garcia‐Segura, Luis Miguel
المساهمون: Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable, European Regional Development Fund
المصدر: Aging Cell ; volume 19, issue 8 ; ISSN 1474-9718 1474-9726
الوصف: Microglia dysfunction and activation are important hallmarks of the aging brain and are concomitant with age‐related neurodegeneration and cognitive decline. Age‐associated changes in microglia migration and phagocytic capacity result in maladaptive responses, chronic neuroinflammation, and worsened outcomes in neurodegenerative disorders. Given the sex bias in the incidence, prevalence, and therapy response of most neurological disorders, we have here examined whether the phagocytic activity of aged microglia is different in males and females. With this aim, the phagocytosis activity of male and female cells was compared in an in vitro aged microglia model and in microglia isolated from adult (5‐month‐old) or aged (18‐month‐old) mice. In both models, the phagocytosis of neural debris increased with aging in male and female cells and was higher in aged female microglia than in aged male cells. However, female aged microglia lost its ability to adapt its phagocytic activity to inflammatory conditions. These findings suggest that microglia phagocytosis of neural debris may represent a previously unexplored neuroprotective characteristic of aged microglia that may contribute to the generation of sex differences in the manifestation of neurodegenerative diseases.
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3دورية أكاديمية
المؤلفون: Pinto‐Benito, Daniel, Paradela‐Leal, Carmen, Ganchala, Danny, de Castro‐Molina, Paula, Arevalo, Maria‐Angeles
المصدر: Glia ; volume 70, issue 6 ; ISSN 0894-1491 1098-1136
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4دورية أكاديمية
المؤلفون: Rubio, Nazario, Cerciat, Marie, Unkila, Mikko, Garcia‐Segura, Luis M., Arevalo, Maria‐Angeles
المصدر: Immunology ; volume 133, issue 3, page 360-369 ; ISSN 0019-2805 1365-2567
الوصف: Summary This paper describes an experimental model of neuroinflammation based on the production of interleukin‐6 (IL‐6) by neural glial cells infected with Theiler’s murine encephalomyelitis virus (TMEV). Production of IL‐6 mRNA in mock‐infected and TMEV‐infected SJL/J murine astrocytes was examined using the Affymetrix murine genome U74v2 DNA microarray. The IL‐6 mRNA from infected cells showed an eightfold increase in hybridization to a sequence encoding IL‐6 located on chromosome number 5. Quantitative real‐time reverse transcription PCR (qPCR) was used to study the regulation of IL‐6 expression. The presence of IL‐6 in the supernatants of TMEV‐infected astrocyte cultures was quantified by ELISA and found to be weaker than in cultures of infected macrophages. The IL‐6 was induced by whole TMEV virions, but not by Ad.βGal adenovirus, purified TMEV capsid proteins, or UV‐inactivated virus. Two recombinant inflammatory cytokines, IL‐1α and tumour necrosis factor‐α were also found to be potent inducers of IL‐6. The secreted IL‐6 was biologically active because it fully supported B9 hybridoma proliferation in a [ 3 H]thymidine incorporation bioassay. The cerebrospinal fluid of infected mice contained IL‐6 during the acute encephalitis phase, peaking at days 2–4 post‐infection. Finally, this in vitro neuroinflammation model was fully inhibited, as demonstrated by ELISA and qPCR, by five selective oestrogen receptor modulators.
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5دورية أكاديمية
المصدر: Journal of Neurochemistry ; volume 111, issue 6, page 1425-1433 ; ISSN 0022-3042 1471-4159
الوصف: In the nervous system, both the shape and connectivity of neurons are strongly influenced by soluble, extracellular factors. Indeed, we recently demonstrated that after binding to p75 NTR , the common neurotrophin receptor, nerve growth factor (NGF) controls the morphology and connectivity of cultured mouse hippocampal neurons by encouraging the production of fewer yet longer dendrites, and by augmenting GABAergic connectivity. These effects of NGF are mediated by the differential expression of Enhancer‐of‐split 1/5 homologs and neurogenin 3 . Amyloid β (Aβ), a pathogenic agent in Alzheimer’s disease (AD) is known to bind to p75 NTR , hence we studied its influence on cultured hippocampal neurons. At 800 nM, Aβ(1–40) prevents NGF‐induced activation of NF‐κB and consequently, it depresses the expression of Enhancer‐of‐split 1 . Thus, at this concentration, the effect of Aβ on neurons is antagonistic to those provoked by NGF and accordingly, neurons sprout more yet shorter dendrites and their GABAergic input decreases. In contrast, at lower concentration, 20 nM, the amyloid induces cellular effects similar to those induced by NGF, both in terms of gene expression, neuronal morphology, and GABAergic connectivity. Our results demonstrate that Aβ may act as a neurotrophic factor that mimics the activity of NGF. However, at higher concentrations, the amyloid behaves as an antagonist of NGF, contributing to the advent of AD.
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6دورية أكاديمية
المصدر: Journal of Neurochemistry ; volume 104, issue 1, page 100-112 ; ISSN 0022-3042 1471-4159
الوصف: Intracerebral infection with Theiler’s murine encephalomyelitis virus (TMEV) induces a demyelinating disease that resembles human multiple sclerosis. In order to delineate the early events in this virus‐induced neuroinflammatory disease, we have analyzed global GTPases gene activation following TMEV infection of murine brain astrocytes. DNA hybridization microchip analysis demonstrated that 10 sequences described as GTPbinding proteins and GTPases in different protein databases were over‐expressed, in response to this infectious agent in astroglial cells. We have first characterized both the GTP‐binding and GTPase activities in uninfected astrocyte membranes from a biochemical point of view. The increase in such activities was further validated in TMEV‐infected astrocytes, peaking 2–4 h after infection. Over‐expression is also induced by the inflammation‐related chemokines interleukin‐6 and interferon‐γ but not by interleukin‐1α or tumor necrosis factor‐α. From the many GTPases that could be over‐expressed we have studied two, because of its biological significance; Ras p21 and the subunit αi2 of G proteins. Western blots revealed increases in both proteins after infection with TMEV, in accordance with the previous enzymologic results. An increase in the active form of Ras (the GTP bound form) in cell lysates was also confirmed by affinity binding to a glutathione‐S‐transferase‐fusion protein, following TMEV infection. A final demonstration of physiological up‐regulation is provided by UV cross‐linking of membrane proteins with the hydrolysis‐resistant GTP agonist GTP [γ‐ 35 S]. This technique allow us to detect, after SDS‐PAGE, the increase of two further majoritary GTPbinding proteins with MW of 62 and 49 KDa. A quantitative analysis of four selected genes coding for p21 ras, Gαi2 subunit of protein G, Munc‐18 and protein interacting with C kinase 1, was performed by real‐time RT‐PCR to verify the microarray results. The study of GTPase activity and of the above genes by RT‐PCR in brains of sick mice, ...
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7دورية أكاديمية
المؤلفون: Salama‐Cohen, Patricia, Arévalo, María‐Ángeles, Grantyn, Rosemarie, Rodríguez‐Tébar, Alfredo
المصدر: Journal of Neurochemistry ; volume 97, issue 5, page 1269-1278 ; ISSN 0022-3042 1471-4159
الوصف: We have previously shown that dendrite morphology of cultured hippocampal neurones is controlled by Notch receptor activation or binding of nerve growth factor (NGF) to its low affinity receptor p75 NTR , i.e. processes that up‐regulate the expression of the Homologue of enhancer of split 1 and 5 . Thus, the increased expression of these genes decreases the number of dendrites, whereas abrogation of Homologue of enhancer of split 1/5 activity stimulates the outgrowth of new dendrites. Here, we show that Neurogenin 3 is a proneural gene that is negatively regulated by Homologue of enhancer of split 1/5 . It also influences dendrite morphology. Hence, a deficit of Notch or NGF/p75 NTR activation can lead to the production of high levels of Neurogenin 3, which stimulates the outgrowth of new dendrites. Conversely, activation of either Notch or p75 NTR depressed Neurogenin 3 expression, which not only decreased the number of dendrites but also favoured inhibitory (GABAergic) synaptogenesis, thereby diminishing the ratios of excitatory/inhibitory inputs. NGF also augmented the levels of mRNA encoding the vesicular inhibitory amino acid transporter, but it did not affect the fraction of GAD65/67‐positive neurones. Conversely, overexpression of Neurogenin 3 largely reduced the number of inhibitory synaptic contacts and, consequently, produced a strong increase in the ratios of excitatory/inhibitory synaptic terminals. Our results reveal a hitherto unknown contribution of NGF/p75 NTR to dendritic and synaptic plasticity through Neurogenin 3 signalling.
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8دورية أكاديمية
المؤلفون: Yanguas‐Casás, Natalia, Crespo‐Castrillo, Andrea, de Ceballos, Maria L., Chowen, Julie A., Azcoitia, Iñigo, Arevalo, Maria Angeles, Garcia‐Segura, Luis M.
المساهمون: MINECO, CIBER, Instituto de Salud Carlos III
المصدر: Glia ; volume 66, issue 3, page 522-537 ; ISSN 0894-1491 1098-1136
الوصف: Sex differences in the incidence, clinical manifestation, disease course, and prognosis of neurological diseases, such as autism spectrum disorders or Alzheimer's disease, have been reported. Obesity has been postulated as a risk factor for cognitive decline and Alzheimer's disease and, during pregnancy, increases the risk of autism spectrum disorders in the offspring. Obesity is associated with increased serum and brain levels of free fatty acids, such as palmitic acid, which activate microglial cells triggering a potent inflammatory cascade. In this study, we have determined the effect of palmitic acid in the inflammatory profile, motility, and phagocytosis of primary male and female microglia, both in basal conditions and in the presence of a pro‐inflammatory stimulus (interferon‐γ). Male microglia in vitro showed higher migration than female microglia under basal and stimulated conditions. In contrast, female microglia had higher basal and stimulated phagocytic activity than male microglia. Palmitic acid did not affect basal migration or phagocytosis, but abolished the migration and phagocytic activity of male and female microglia in response to interferon‐γ. These findings extend previous observations of sex differences in microglia and suggest that palmitic acid impairs the protective responses of these cells.
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9دورية أكاديمية
المؤلفون: Simon‐Areces, Julia, Membrive, Gema, Garcia‐Fernandez, Carmen, Garcia‐Segura, Luis Miguel, Arevalo, Maria‐Angeles
المصدر: Journal of Comparative Neurology ; volume 518, issue 10, page 1814-1824 ; ISSN 0021-9967 1096-9861
الوصف: Neurogenin 3 ( Ngn3 ), a proneural gene controlled by the Notch receptor, is implicated in the control of dendrite morphology and synaptic plasticity of cultured hippocampal neurons. Here we report the localization and subcellular distribution of Ngn3 in the hippocampus in vivo and in neuronal cultures. In situ hybridization showed Ngn3 mRNA expression in the pyramidal layer and dentate gyrus of adult mouse hippocampus. Immunohistochemistry studies revealed that Ngn3 localization is mostly cytoplasmic in the hippocampal eminence at embryonic day (E)17 and postnatal day (P)0. At P10 it is cytoplasmic in CA1–CA3 pyramidal neurons and nuclear in granule cells of the dentate gyrus. In the adult hippocampus Ngn3 is localized in the nucleus and cytoplasm of both pyramidal neurons and granule cells. During development of cultured hippocampal neurons, Ngn3 mRNA expression is higher at stages of neuronal polarization, as judged by reverse‐transcription polymerase chain reaction (RT‐PCR), and it is mostly cytoplasmic. The tracking of the subcellular localization of Ngn3 in neurons infected with a virus expressing myc‐Ngn3 suggests that the protein is quickly translocated to the cell nucleus after synthesis and then reexported to the cytoplasm. Treatment with leptomycinB, a potent and specific inhibitor of the exportin CRM1, induced its accumulation into the nucleus, suggesting that CRM1 mediates the nuclear export of Ngn3. These results suggest that Ngn3 may play a role in neuronal development by actions in the cytoplasm. J. Comp. Neurol. 518:1814–1824, 2010. © 2009 Wiley‐Liss, Inc.
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10دورية أكاديمية
المصدر: Veterinary Dermatology ; volume 15, issue 6, page 349-356 ; ISSN 0959-4493 1365-3164
الوصف: Lamb, beef and cow's milk are common causes of cutaneous adverse food reactions in dogs. The aim of this study was to identify the proteins responsible for cutaneous adverse reactions to these foods. Ten dogs with allergen‐specific serum immunoglobulin (Ig)E to lamb, beef and cow's milk were included in the study. These dogs had been diagnosed with cutaneous adverse food reactions by convincing clinical history and food‐elimination diet trials followed by challenge exposure. Sera were analysed by enzyme‐linked immunosorbent assay with bovine proteins and SDS–PAGE immunoblots with lamb, beef and cow's milk extracts. All the dogs had specific IgE against bovine IgG, and it was the only protein in the cow's milk extract that bound IgE from the sera studied. In the lamb and beef extracts, the major allergens recognized by the specific IgE of most sera had molecular masses between 51 and 58 kDa, which were identified as phosphoglucomutase and the IgG heavy chain. Other IgE‐binding proteins with molecular masses of 27, 31, 33, 37 and 42 kDa were also detected with some sera. Our results indicate that bovine IgG is a major allergen in cow's milk and hence it appears to be a source of cross‐reactivity with beef and probably with lamb because of the high homology with ovine immunoglobulins. These results are similar to those found for meat allergy in humans. However, this is the first time that phosphoglucomutase has been identified as an important allergen involved in allergic reactions to lamb and beef.
