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Islam R, Choudhary H, Rajan R, Vrionis F, Hanafy KA. An overview on microglial origin, distribution, and phenotype in Alzheimer's disease. J Cell Physiol 2024; 239:e30829. [PMID: 35822939 PMCID: PMC9837313 DOI: 10.1002/jcp.30829] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/12/2022] [Accepted: 07/04/2022] [Indexed: 01/17/2023]
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease that is responsible for about one-third of dementia cases worldwide. It is believed that AD is initiated with the deposition of Ab plaques in the brain. Genetic studies have shown that a high number of AD risk genes are expressed by microglia, the resident macrophages of brain. Common mode of action by microglia cells is neuroinflammation and phagocytosis. Moreover, it has been discovered that inflammatory marker levels are increased in AD patients. Recent studies advocate that neuroinflammation plays a major role in AD progression. Microglia have different activation profiles depending on the region of brain and stimuli. In different activation, profile microglia can generate either pro-inflammatory or anti-inflammatory responses. Microglia defend brain cells from pathogens and respond to injuries; also, microglia can lead to neuronal death along the way. In this review, we will bring the different roles played by microglia and microglia-related genes in the progression of AD.
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Affiliation(s)
- Rezwanul Islam
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL
| | - Hadi Choudhary
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL
| | - Robin Rajan
- Marcus Neuroscience Institute, Boca Raton Medical Center, Boca Raton, FL
| | - Frank Vrionis
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL
- Marcus Neuroscience Institute, Boca Raton Medical Center, Boca Raton, FL
| | - Khalid A. Hanafy
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL
- Marcus Neuroscience Institute, Boca Raton Medical Center, Boca Raton, FL
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2
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Cammarota M, Boscia F. Contribution of Oligodendrocytes, Microglia, and Astrocytes to Myelin Debris Uptake in an Explant Model of Inflammatory Demyelination in Rats. Cells 2023; 12:2203. [PMID: 37681935 PMCID: PMC10486984 DOI: 10.3390/cells12172203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/09/2023] Open
Abstract
The internalization and degradation of myelin in glia contributes to the resolution of neuroinflammation and influences disease progression. The identification of a three-dimensional experimental model to study myelin processing under neuroinflammation will offer a novel approach for studying treatment strategies favoring inflammation resolution and neuroprotection. Here, by using a model of neuroinflammation in hippocampal explants, we show that myelin debris accumulated immediately after insult and declined at 3 days, a time point at which tentative repair processes were observed. Olig2+ oligodendrocytes upregulated the LRP1 receptor and progressively increased MBP immunoreactivity both at peri-membrane sites and within the cytosol. Oligodendrocyte NG2+ precursors increased in number and immunoreactivity one day after insult, and moderately internalized MBP particles. Three days after insult MBP was intensely coexpressed by microglia and, to a much lesser extent, by astrocytes. The engulfment of both MBP+ debris and whole MBP+ cells contributed to the greatest microglia response. In addition to improving our understanding of the spatial-temporal contribution of glial scarring to myelin uptake under neuroinflammation, our findings suggest that the exposure of hippocampal explants to LPS + IFN-γ-induced neuroinflammation may represent a valuable demyelination model for studying both the extrinsic and intrinsic myelin processing by glia under neuroinflammation.
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Affiliation(s)
| | - Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive Sciences and Dentistry, School of Medicine, Federico II University of Naples, 80131 Naples, Italy;
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3
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Cammarota M, Ferlenghi F, Vacondio F, Vincenzi F, Varani K, Bedini A, Rivara S, Mor M, Boscia F. Combined targeting of fatty acid amide hydrolase and melatonin receptors promotes neuroprotection and stimulates inflammation resolution in rats. Br J Pharmacol 2022; 180:1316-1338. [PMID: 36526591 DOI: 10.1111/bph.16014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 11/09/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND AND PURPOSE Devising novel strategies to therapeutically favour inflammation resolution and provide neuroprotection is an unmet clinical need. Enhancing endocannabinoid tone by inhibiting the catabolic enzyme fatty acid amide hydrolase (FAAH), or stimulating melatonin receptors has therapeutic potential to treat neuropathological states in which neuroinflammation plays a central role. EXPERIMENTAL APPROACH A rodent hippocampal explant model of inflammatory injury was used to assess the effects of UCM1341, a dual-acting compound with FAAH inhibitory action and agonist activity at melatonin receptors, against neuroinflammatory damage. FAAH activity was measured by a radiometric assay, and N-acylethanolamine levels were assessed by HPLC-MS/MS methods. FAAH distribution, evolution of inflammation and the contribution of UCM1341 to the expression of proteins controlling macrophage behaviour were investigated by biochemical and confocal analyses. KEY RESULTS UCM1341 exhibited greater neuroprotection against neuroinflammatory degeneration, compared with the reference compounds URB597 (FAAH inhibitor) and melatonin. During neuroinflammation, UCM1341 augmented the levels of anandamide and N-oleoylethanolamine, but not N-palmitoylethanolamine, up-regulated PPAR-α levels, attenuated demyelination and prevented the release of TNF-α. UCM1341 modulated inflammatory responses by contributing to microglia/macrophage polarization, stimulating formation of lipid-laden macrophages and regulating expression of proteins controlling cholesterol metabolism and efflux. The neuroprotective effects of UCM1341 were prevented by PPARα, TRPV1 and melatonin receptor antagonists. CONCLUSION AND IMPLICATIONS UCM1341, by enhancing endocannabinoid and melatoninergic signalling, benefits neuroprotection and stimulates inflammation resolution pathways. Our findings provide an encouraging prospect of therapeutically targeting endocannabinoid and melatoninergic systems in inflammatory demyelinating states in the CNS.
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Affiliation(s)
- Mariarosaria Cammarota
- Division of Pharmacology, Department of Neuroscience, Reproductive Sciences and Dentistry, School of Medicine, Federico II University of Naples, Naples, Italy
| | | | | | - Fabrizio Vincenzi
- Department of Translational Medicine, University of Ferrara, Ferrara, Italy
| | - Katia Varani
- Department of Translational Medicine, University of Ferrara, Ferrara, Italy
| | - Annalida Bedini
- Department of Biomolecular Sciences, University of Urbino 'Carlo Bo', Urbino, Italy
| | - Silvia Rivara
- Department of Food and Drug, University of Parma, Parma, Italy
| | - Marco Mor
- Department of Food and Drug, University of Parma, Parma, Italy
| | - Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive Sciences and Dentistry, School of Medicine, Federico II University of Naples, Naples, Italy
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4
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Španić E, Langer Horvat L, Ilić K, Hof PR, Šimić G. NLRP1 Inflammasome Activation in the Hippocampal Formation in Alzheimer's Disease: Correlation with Neuropathological Changes and Unbiasedly Estimated Neuronal Loss. Cells 2022; 11:2223. [PMID: 35883667 PMCID: PMC9324749 DOI: 10.3390/cells11142223] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/12/2022] [Accepted: 07/16/2022] [Indexed: 02/04/2023] Open
Abstract
Neuroinflammation is one of the core pathological features of Alzheimer's disease (AD) as both amyloid β (Aβ) and tau monomers and oligomers can trigger the long-term pro-inflammatory phenotype of microglial cells with consequent overactivation of the inflammasomes. To investigate the NLRP1 inflammasome activation in AD, we analyzed the expression of NLRP1, ASC, cleaved gasdermin (cGSDMD), and active caspase-6 (CASP-6) proteins in each hippocampal subdivision (hilar part of CA3, CA2/3, CA1, subiculum) of postmortem tissue of 9 cognitively healthy controls (HC) and 11 AD patients whose disease duration varied from 3 to 7 years after the clinical diagnosis. The total number of neurons, along with the total number of neurofibrillary tangles (NFTs), were estimated in Nissl- and adjacent modified Bielschowsky-stained sections, respectively, using the optical disector method. The same 9 HC and 11 AD cases were additionally semiquantitatively analyzed for expression of IBA1, HLA-DR, and CD68 microglial markers. Our results show that the expression of NLRP1, ASC, and CASP-6 is present in a significantly greater number of hippocampal formation neurons in AD brains compared to controls, suggesting that the NLRP1 inflammasome is more active in the AD brain. None of the investigated inflammasome and microglial markers were found to correlate with the age of the subjects or the duration of AD. However, besides positive correlations with microglial IBA1 expression in the subiculum and with microglial CD68 expression in the CA1 field and subiculum in the AD group, the overall NLRP1 expression in the hippocampal formation was positively correlated with the number of NFTs, thus providing a causal link between neuroinflammation and neurofibrillary degeneration. The accumulation of AT8-immunoreactive phosphorylated tau proteins that we observed at nuclear pores of large pyramidal neurons of the Ammon's horn further supports their role in the extent of neuronal dysfunction and degeneration in AD. This is important because unlike fibrillar amyloid-β deposits that are not related to dementia severity, total NFTs and neuron numbers in the hippocampal formation, especially in the CA1 field, are the best correlates of cognitive deterioration in both human brain aging and AD. Our findings also support the notion that the CA2 field vulnerability is strongly linked to specific susceptibilities to different tauopathies, including primary age-related tauopathy. Altogether, these findings contrast with reports of nonsignificant microglial activation in aged nonhuman primates and indicate that susceptibility to inflammasome activation may render the human brain comparatively more vulnerable to neurodegenerative changes and AD. In conclusion, our results confirm a key role of NLRP1 inflammasome in AD pathogenesis and suggest NLRP1 as a potential diagnostic marker and therapeutic target to slow or prevent AD progression.
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Affiliation(s)
- Ena Španić
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb School of Medicine, Šalata 12, 10000 Zagreb, Croatia; (E.Š.); (L.L.H.); (K.I.)
| | - Lea Langer Horvat
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb School of Medicine, Šalata 12, 10000 Zagreb, Croatia; (E.Š.); (L.L.H.); (K.I.)
| | - Katarina Ilić
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb School of Medicine, Šalata 12, 10000 Zagreb, Croatia; (E.Š.); (L.L.H.); (K.I.)
- BRAIN Centre, Institute of Psychiatry, Psychology, and Neuroscience, King’s College London, London WC2R 2LS, UK
| | - Patrick R. Hof
- Nash Family Department of Neuroscience, Friedman Brain Institute, and Ronald M. Loeb Center for Alzheimer’s Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
| | - Goran Šimić
- Department of Neuroscience, Croatian Institute for Brain Research, University of Zagreb School of Medicine, Šalata 12, 10000 Zagreb, Croatia; (E.Š.); (L.L.H.); (K.I.)
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5
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Cammarota M, de Rosa V, Pannaccione A, Secondo A, Tedeschi V, Piccialli I, Fiorino F, Severino B, Annunziato L, Boscia F. Rebound effects of NCX3 pharmacological inhibition: A novel strategy to accelerate myelin formation in oligodendrocytes. Biomed Pharmacother 2021; 143:112111. [PMID: 34481380 DOI: 10.1016/j.biopha.2021.112111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 08/20/2021] [Accepted: 08/23/2021] [Indexed: 11/18/2022] Open
Abstract
The Na+/Ca2+ exchanger NCX3 is an important regulator of sodium and calcium homeostasis in oligodendrocyte lineage. To date, no information is available on the effects resulting from prolonged exposure to NCX3 blockers and subsequent drug washout in oligodendroglia. Here, we investigated, by means of biochemical, morphological and functional analyses, the pharmacological effects of the NCX3 inhibitor, the 5-amino-N-butyl-2-(4-ethoxyphenoxy)-benzamide hydrochloride (BED), on NCXs expression and activity, as well as intracellular [Na+]i and [Ca2+]i levels, during treatment and following drug washout both in human MO3.13 oligodendrocytes and rat primary oligodendrocyte precursor cells (OPCs). BED exposure antagonized NCX activity, induced OPCs proliferation and [Na+]i accumulation. By contrast, 2 days of BED washout after 4 days of treatment significantly upregulated low molecular weight NCX3 proteins, reversed NCX activity, and increased intracellular [Ca2+]i. This BED-free effect was accompanied by an upregulation of NCX3 expression in oligodendrocyte processes and accelerated expression of myelin markers in rat primary oligodendrocytes. Collectively, our findings show that the pharmacological inhibition of the NCX3 exchanger with BED blocker maybe followed by a rebound increase in NCX3 expression and reversal activity that accelerate myelin sheet formation in oligodendrocytes. In addition, they indicate that a particular attention should be paid to the use of NCX inhibitors for possible rebound effects, and suggest that further studies will be necessary to investigate whether selective pharmacological modulation of NCX3 exchanger may be exploited to benefit demyelination and remyelination in demyelinating diseases.
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Affiliation(s)
- Mariarosaria Cammarota
- Division of Pharmacology, Department of Neuroscience, Reproductive Sciences and Dentistry, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Valeria de Rosa
- Division of Pharmacology, Department of Neuroscience, Reproductive Sciences and Dentistry, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Anna Pannaccione
- Division of Pharmacology, Department of Neuroscience, Reproductive Sciences and Dentistry, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Agnese Secondo
- Division of Pharmacology, Department of Neuroscience, Reproductive Sciences and Dentistry, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Valentina Tedeschi
- Division of Pharmacology, Department of Neuroscience, Reproductive Sciences and Dentistry, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Ilaria Piccialli
- Division of Pharmacology, Department of Neuroscience, Reproductive Sciences and Dentistry, School of Medicine, Federico II University of Naples, Naples, Italy
| | | | - Beatrice Severino
- Department of Pharmacy, Federico II University of Naples, Naples, Italy
| | | | - Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive Sciences and Dentistry, School of Medicine, Federico II University of Naples, Naples, Italy.
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6
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Kotliarova A, Sidorova YA. Glial Cell Line-Derived Neurotrophic Factor Family Ligands, Players at the Interface of Neuroinflammation and Neuroprotection: Focus Onto the Glia. Front Cell Neurosci 2021; 15:679034. [PMID: 34220453 PMCID: PMC8250866 DOI: 10.3389/fncel.2021.679034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 05/21/2021] [Indexed: 12/25/2022] Open
Abstract
Well-known effects of neurotrophic factors are related to supporting the survival and functioning of various neuronal populations in the body. However, these proteins seem to also play less well-documented roles in glial cells, thus, influencing neuroinflammation. This article summarizes available data on the effects of glial cell line derived neurotrophic factor (GDNF) family ligands (GFLs), proteins providing trophic support to dopaminergic, sensory, motor and many other neuronal populations, in non-neuronal cells contributing to the development and maintenance of neuropathic pain. The paper also contains our own limited data describing the effects of small molecules targeting GFL receptors on the expression of the satellite glial marker IBA1 in dorsal root ganglia of rats with surgery- and diabetes-induced neuropathy. In our experiments activation of GFLs receptors with either GFLs or small molecule agonists downregulated the expression of IBA1 in this tissue of experimental animals. While it can be a secondary effect due to a supportive role of GFLs in neuronal cells, growing body of evidence indicates that GFL receptors are expressed in glial and peripheral immune system cells. Thus, targeting GFL receptors with either proteins or small molecules may directly suppress the activation of glial and immune system cells and, therefore, reduce neuroinflammation. As neuroinflammation is considered to be an important contributor to the process of neurodegeneration these data further support research efforts to modulate the activity of GFL receptors in order to develop disease-modifying treatments for neurodegenerative disorders and neuropathic pain that target both neuronal and glial cells.
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Affiliation(s)
- Anastasiia Kotliarova
- Laboratory of Molecular Neuroscience, Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Yulia A Sidorova
- Laboratory of Molecular Neuroscience, Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
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7
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Marshall P, Garton DR, Taira T, Võikar V, Vilenius C, Kulesskaya N, Rivera C, Andressoo JO. Elevated expression of endogenous glial cell line-derived neurotrophic factor impairs spatial memory performance and raises inhibitory tone in the hippocampus. Eur J Neurosci 2021; 53:2469-2482. [PMID: 33481269 DOI: 10.1111/ejn.15126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 01/07/2021] [Accepted: 01/19/2021] [Indexed: 01/16/2023]
Abstract
Parvalbumin-positive interneurons (PV+) are a key component of inhibitory networks in the brain and are known to modulate memory and learning by shaping network activity. The mechanisms of PV+ neuron generation and maintenance are not fully understood, yet current evidence suggests that signalling via the glial cell line-derived neurotrophic factor (GDNF) receptor GFRα1 positively modulates the migration and differentiation of PV+ interneurons in the cortex. Whether GDNF also regulates PV+ cells in the hippocampus is currently unknown. In this study, we utilized a Gdnf "hypermorph" mouse model where GDNF is overexpressed from the native gene locus, providing greatly increased spatial and temporal specificity of protein expression over established models of ectopic expression. Gdnfwt/hyper mice demonstrated impairments in long-term memory performance in the Morris water maze test and an increase in inhibitory tone in the hippocampus measured electrophysiologically in acute brain slice preparations. Increased PV+ cell number was confirmed immunohistochemically in the hippocampus and in discrete cortical areas and an increase in epileptic seizure threshold was observed in vivo. The data consolidate prior evidence for the actions of GDNF as a regulator of PV+ cell development in the cortex and demonstrate functional effects upon network excitability via modulation of functional GABAergic signalling and under epileptic challenge.
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Affiliation(s)
- Pepin Marshall
- HiLIFE Neuroscience Centre, University of Helsinki, Helsinki, Finland
| | - Daniel R Garton
- Department of Pharmacology, Faculty of Medicine & Helsinki Institute of Life Science (HiLIFE) Helsinki, University of Helsinki, Helsinki, Finland
| | - Tomi Taira
- HiLIFE Neuroscience Centre, University of Helsinki, Helsinki, Finland.,Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Vootele Võikar
- HiLIFE Neuroscience Centre, University of Helsinki, Helsinki, Finland
| | - Carolina Vilenius
- HiLIFE Neuroscience Centre, University of Helsinki, Helsinki, Finland
| | | | - Claudio Rivera
- HiLIFE Neuroscience Centre, University of Helsinki, Helsinki, Finland.,Institut de Neurobiologie de la Méditerranée, INMED UMR901, Marseille, France
| | - Jaan-Olle Andressoo
- Department of Pharmacology, Faculty of Medicine & Helsinki Institute of Life Science (HiLIFE) Helsinki, University of Helsinki, Helsinki, Finland.,Karolinska Institute, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society (NVS), Stockholm, Sweden
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8
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Qing J, Liu X, Wu Q, Zhou M, Zhang Y, Mazhar M, Huang X, Wang L, He F. Hippo/YAP Pathway Plays a Critical Role in Effect of GDNF Against Aβ-Induced Inflammation in Microglial Cells. DNA Cell Biol 2020; 39:1064-1071. [PMID: 32255663 DOI: 10.1089/dna.2019.5308] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Neuroinflammation is a critical mechanism responsible for the progression of Alzheimer's disease (AD). Recent studies reveal that Hippo/Yes-associated protein (YAP) signaling pathway is highly associated with a series of inflammation-related disorders. Glial cell line-derived neurotrophic factor (GDNF), with its neurotrophic and anti-apoptotic functions for nervous system, has been demonstrated to decrease the expression of proinflammatory mediators. Here we investigated whether Hippo/YAP signaling may affect amyloid-β (Aβ)-induced proinflammatory cytokine production in microglial cells and explored its relationship with the anti-inflammation function of GDNF. The results showed that Aβ induced a decrease in the expression of YAP in microglia cells. YAP agonist XMU-MP-1 or its overexpression in microglial cells caused decreased expression of proinflammatory cytokines, whereas YAP antagonist Verteporfin or knockdown of YAP had the opposite effect. Treatment with GDNF resulted in upregulation of YAP expression and reduced the production of proinflammatory cytokines. Meanwhile YAP knockdown weakened the function of GDNF in microglial cells. In conclusion, Hippo/YAP pathway plays a critical role in effect of GDNF against Aβ-induced inflammatory response in microglia. Targeting GDNF or Hippo/YAP signaling may be promising therapeutic approach for the treatment of AD.
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Affiliation(s)
- Jie Qing
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China.,Research Center of Integrated Traditional Chinese and Western Medicine, Affiliated Traditional Medicine Hospital, Southwest Medical University, Luzhou, China
| | - Xiaoheng Liu
- Research Center of Integrated Traditional Chinese and Western Medicine, Affiliated Traditional Medicine Hospital, Southwest Medical University, Luzhou, China
| | - Quan Wu
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Mengjie Zhou
- Research Center of Integrated Traditional Chinese and Western Medicine, Affiliated Traditional Medicine Hospital, Southwest Medical University, Luzhou, China
| | - Yuwei Zhang
- Research Center of Integrated Traditional Chinese and Western Medicine, Affiliated Traditional Medicine Hospital, Southwest Medical University, Luzhou, China
| | - Maryam Mazhar
- Research Center of Integrated Traditional Chinese and Western Medicine, Affiliated Traditional Medicine Hospital, Southwest Medical University, Luzhou, China
| | - Xiaoli Huang
- The Center of Gerontology and Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, China
| | - Li Wang
- Research Center of Integrated Traditional Chinese and Western Medicine, Affiliated Traditional Medicine Hospital, Southwest Medical University, Luzhou, China
| | - Fuqian He
- The Center of Gerontology and Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, China
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9
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Duarte Azevedo M, Sander S, Tenenbaum L. GDNF, A Neuron-Derived Factor Upregulated in Glial Cells during Disease. J Clin Med 2020; 9:jcm9020456. [PMID: 32046031 PMCID: PMC7073520 DOI: 10.3390/jcm9020456] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 01/31/2020] [Accepted: 02/03/2020] [Indexed: 12/20/2022] Open
Abstract
In a healthy adult brain, glial cell line-derived neurotrophic factor (GDNF) is exclusively expressed by neurons, and, in some instances, it has also been shown to derive from a single neuronal subpopulation. Secreted GDNF acts in a paracrine fashion by forming a complex with the GDNF family receptor α1 (GFRα1), which is mainly expressed by neurons and can act in cis as a membrane-bound factor or in trans as a soluble factor. The GDNF/GFRα1 complex signals through interactions with the “rearranged during transfection” (RET) receptor or via the neural cell adhesion molecule (NCAM) with a lower affinity. GDNF can also signal independently from GFRα1 by interacting with syndecan-3. RET, which is expressed by neurons involved in several pathways (nigro–striatal dopaminergic neurons, motor neurons, enteric neurons, sensory neurons, etc.), could be the main determinant of the specificity of GDNF’s pro-survival effect. In an injured brain, de novo expression of GDNF occurs in glial cells. Neuroinflammation has been reported to induce GDNF expression in activated astrocytes and microglia, infiltrating macrophages, nestin-positive reactive astrocytes, and neuron/glia (NG2) positive microglia-like cells. This disease-related GDNF overexpression can be either beneficial or detrimental depending on the localization in the brain and the level and duration of glial cell activation. Some reports also describe the upregulation of RET and GFRα1 in glial cells, suggesting that GDNF could modulate neuroinflammation.
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10
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Chamera K, Trojan E, Szuster-Głuszczak M, Basta-Kaim A. The Potential Role of Dysfunctions in Neuron-Microglia Communication in the Pathogenesis of Brain Disorders. Curr Neuropharmacol 2020; 18:408-430. [PMID: 31729301 PMCID: PMC7457436 DOI: 10.2174/1570159x17666191113101629] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 10/15/2019] [Accepted: 11/10/2019] [Indexed: 12/18/2022] Open
Abstract
The bidirectional communication between neurons and microglia is fundamental for the proper functioning of the central nervous system (CNS). Chemokines and clusters of differentiation (CD) along with their receptors represent ligand-receptor signalling that is uniquely important for neuron - microglia communication. Among these molecules, CX3CL1 (fractalkine) and CD200 (OX-2 membrane glycoprotein) come to the fore because of their cell-type-specific localization. They are principally expressed by neurons when their receptors, CX3CR1 and CD200R, respectively, are predominantly present on the microglia, resulting in the specific axis which maintains the CNS homeostasis. Disruptions to this balance are suggested as contributors or even the basis for many neurological diseases. In this review, we discuss the roles of CX3CL1, CD200 and their receptors in both physiological and pathological processes within the CNS. We want to underline the critical involvement of these molecules in controlling neuron - microglia communication, noting that dysfunctions in their interactions constitute a key factor in severe neurological diseases, such as schizophrenia, depression and neurodegeneration-based conditions.
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Affiliation(s)
- Katarzyna Chamera
- Department of Experimental Neuroendocrinology, Laboratory of Immunoendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna St. 31-343Kraków, Poland
| | - Ewa Trojan
- Department of Experimental Neuroendocrinology, Laboratory of Immunoendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna St. 31-343Kraków, Poland
| | - Magdalena Szuster-Głuszczak
- Department of Experimental Neuroendocrinology, Laboratory of Immunoendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna St. 31-343Kraków, Poland
| | - Agnieszka Basta-Kaim
- Department of Experimental Neuroendocrinology, Laboratory of Immunoendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna St. 31-343Kraków, Poland
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11
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Neuroprotection after Hemorrhagic Stroke Depends on Cerebral Heme Oxygenase-1. Antioxidants (Basel) 2019; 8:antiox8100496. [PMID: 31635102 PMCID: PMC6827088 DOI: 10.3390/antiox8100496] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/14/2019] [Accepted: 10/18/2019] [Indexed: 12/21/2022] Open
Abstract
(1) Background: A detailed understanding of the pathophysiology of hemorrhagic stroke is still missing. We hypothesized that expression of heme oxygenase-1 (HO-1) in microglia functions as a protective signaling pathway. (2) Methods: Hippocampal HT22 neuronal cells were exposed to heme-containing blood components and cell death was determined. We evaluated HO-1-induction and cytokine release by wildtype compared to tissue-specific HO-1-deficient (LyzM-Cre.Hmox1 fl/fl) primary microglia (PMG). In a study involving 46 patients with subarachnoid hemorrhage (SAH), relative HO-1 mRNA level in the cerebrospinal fluid were correlated with hematoma size and functional outcome. (3) Results: Neuronal cell death was induced by exposure to whole blood and hemoglobin. HO-1 was induced in microglia following blood exposure. Neuronal cells were protected from cell death by microglia cell medium conditioned with blood. This was associated with a HO-1-dependent increase in monocyte chemotactic protein-1 (MCP-1) production. HO-1 mRNA level in the cerebrospinal fluid of SAH-patients correlated positively with hematoma size. High HO-1 mRNA level in relation to hematoma size were associated with improved functional outcome at hospital discharge. (4) Conclusions: Microglial HO-1 induction with endogenous CO production functions as a crucial signaling pathway in blood-induced inflammation, determining microglial MCP-1 production and the extent of neuronal cell death. These results give further insight into the pathophysiology of neuronal damage after SAH and the function of HO-1 in humans.
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Wang G, Zhou Y, Wang Y, Li D, Liu J, Zhang F. Age-Associated Dopaminergic Neuron Loss and Midbrain Glia Cell Phenotypic Polarization. Neuroscience 2019; 415:89-96. [PMID: 31325563 DOI: 10.1016/j.neuroscience.2019.07.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 07/08/2019] [Accepted: 07/11/2019] [Indexed: 12/20/2022]
Abstract
In response to changes in brain micro-environment caused by aging, microglia could polarize into proinflammatory M1 phenotype and anti-inflammatory M2 phenotype. Besides, astroglia could polarize into A1 phenotype, exhibiting neurotoxicity, or A2 phenotype, showing neuroprotection. This study aimed to investigate the change of glial cells and dopaminergic (DA) neuron in midbrain with age. Two-, 6-, 18- and 28- months old rat brains were collected. The DA neurons were detected using anti-TH and anti-DAT antibodies. The expressions of astroglia markers (glial fibrillary acidic protein, GFAP), microglia markers (ionized calcium binding adaptor molecule 1, Iba-1), M1 markers (tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), M2 markers (arginase 1 (Arg1) and IL-10), A1 markers (lipocalin-2 (Lcn2) and complement C3 (C3), A2 markers (brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) were examined by real time RT-PCR and Western Blotting. DA neuron expressions decreased in 18-, 28- months old rat brains. In addition, microglia and astroglia have different degrees of activation with age. Besides, M1 markers (TNF-α and IL-1β) increased and M2 markers (Arg1 and IL-10) decreased in aged rats. Furthermore, A2 markers (BDNF and GDNF) decreased and A1 markers (Lcn2 and C3) increased in aged rats. Age induced DA neuron loss and influenced midbrain glial cells phenotypic polarization, which might account for the occurrence and pathogenesis of Parkinson's diseases.
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Affiliation(s)
- GuoQing Wang
- Joint International Research Laboratory of Ethnomedicine of Ministry of Education and Key Laboratory of Basic Pharmacology of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China
| | - YanZhen Zhou
- Department of Ear-Nose-Throat Surgery, the Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
| | - YanYing Wang
- Joint International Research Laboratory of Ethnomedicine of Ministry of Education and Key Laboratory of Basic Pharmacology of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China
| | - DaiDi Li
- Joint International Research Laboratory of Ethnomedicine of Ministry of Education and Key Laboratory of Basic Pharmacology of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China
| | - Jie Liu
- Joint International Research Laboratory of Ethnomedicine of Ministry of Education and Key Laboratory of Basic Pharmacology of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China
| | - Feng Zhang
- Joint International Research Laboratory of Ethnomedicine of Ministry of Education and Key Laboratory of Basic Pharmacology of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China.
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Xie F, Zhang F, Min S, Chen J, Yang J, Wang X. Glial cell line-derived neurotrophic factor (GDNF) attenuates the peripheral neuromuscular dysfunction without inhibiting the activation of spinal microglia/monocyte. BMC Geriatr 2018; 18:110. [PMID: 29743034 PMCID: PMC5944173 DOI: 10.1186/s12877-018-0796-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 04/30/2018] [Indexed: 12/13/2022] Open
Abstract
Background Peripheral neuromuscular dysfunctions were found in elderly individuals, and spinal microglia/monocyte plays an important role on this process. This study aims to test whether the glial cell line-derived neurotrophic factor (GDNF) could attenuate age-related neuromuscular dysfunction by inhibiting the activation of spinal microglia/monocyte. Methods Male Sprague-Dawley rats were divided into an adult group and an aged group. The aged rats were intrathecally injected with normal saline (NS) and GDNF. All the rats were harvested 5 days after each injection. The muscular function was tested by compound muscle action potential, and the activation of microglia/monocyte was detected by immunofluorescence staining; cytokines were assayed by enzyme-linked immunosorbent assay; the expression level of GDNF and its known receptor GFR-α in the spinal cord, the expression level of neuregulin-1 (NRG-1) in the sciatic nerve, and the expression level of γ- and α7- ε-nicotinic acetylcholine receptors in the tibialis anterior muscle were measured by western blotting. Results The activated microglia/monocyte was found in the aged rats compared to the adult rats. The aged rats showed a significant neuromuscular dysfunction and cytokine release as well as increased expression of γ- and α7-nAChR. The protein expression of GDNF, GFR-α, and NRG-1 in the aged rats were significantly lower than that in the adult rats. However, the exogenous injection of GDNF could alleviate the neuromuscular dysfunction but not inhibit the activation of spinal microglia/monocyte. Furthermore, the levels of GFR-α and NRG-1 also increased after GDNF treatment. Conclusion The GDNF could attenuate the age-related peripheral neuromuscular dysfunction without inhibiting the activation of microglia/monocyte in the spinal cord.
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Affiliation(s)
- Fei Xie
- Department of Anesthesiology, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1#, Yuan Jia Gang, Chongqing, 400016, China
| | - Fan Zhang
- Department of Anesthesiology, the People's Hospital of Jianyang City, Chengdu, Sichuan, China
| | - Su Min
- Department of Anesthesiology, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1#, Yuan Jia Gang, Chongqing, 400016, China.
| | - Jingyuan Chen
- Department of Anesthesiology, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1#, Yuan Jia Gang, Chongqing, 400016, China
| | - Jun Yang
- Department of Anesthesiology, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1#, Yuan Jia Gang, Chongqing, 400016, China
| | - Xin Wang
- Department of Anesthesiology, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1#, Yuan Jia Gang, Chongqing, 400016, China
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Cho JS, Lee J, Jeong DU, Kim HW, Chang WS, Moon J, Chang JW. Effect of Placenta-Derived Mesenchymal Stem Cells in a Dementia Rat Model via Microglial Mediation: a Comparison between Stem Cell Transplant Methods. Yonsei Med J 2018; 59:406-415. [PMID: 29611403 PMCID: PMC5889993 DOI: 10.3349/ymj.2018.59.3.406] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 01/12/2018] [Accepted: 01/12/2018] [Indexed: 12/21/2022] Open
Abstract
PURPOSE Loss of cholinergic neurons in the hippocampus is a hallmark of many dementias. Administration of stem cells as a therapeutic intervention for patients is under active investigation, but the optimal stem cell type and transplantation modality has not yet been established. In this study, we studied the therapeutic effects of human placenta-derived mesenchymal stem cells (pMSCs) in dementia rat model using either intracerebroventricular (ICV) or intravenous (IV) injections and analyzed their mechanisms of therapeutic action. MATERIALS AND METHODS Dementia modeling was established by intraventricular injection of 192 IgG-saporin, which causes lesion of cholinergic neurons. Sixty-five male Sprague-Dawley rats were divided into five groups: control, lesion, lesion+ICV injection of pMSCs, lesion+IV injection of pMSCs, and lesion+donepezil. Rats were subjected to the Morris water maze and subsequent immunostaining analyses. RESULTS Both ICV and IV pMSC administrations allowed significant cognitive recovery compared to the lesioned rats. Acetylcholinesterase activity was significantly rescued in the hippocampus of rats injected with pMSCs post-lesion. Choline acetyltransferase did not co-localize with pMSCs, showing that pMSCs did not directly differentiate into cholinergic cells. Number of microglial cells increased in lesioned rats and significantly decreased back to normal levels with pMSC injection. CONCLUSION Our results suggest that ICV and IV injections of pMSCs facilitate the recovery of cholinergic neuronal populations and cognitive behavior. This recovery likely occurs through paracrine effects that resemble microglia function rather than direct differentiation of injected pMSCs into cholinergic neurons.
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Affiliation(s)
- Jae Sung Cho
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea
| | - Jihyeon Lee
- Brain Korea 21 PLUS Project for Medical Science and Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Da Un Jeong
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea
| | - Han Wool Kim
- General Research Institute, Gangnam CHA General Hospital, Seoul, Korea
| | - Won Seok Chang
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea
| | - Jisook Moon
- General Research Institute, Gangnam CHA General Hospital, Seoul, Korea
- Department of Bioengineering, College of Life Science, CHA University, Seoul, Korea
| | - Jin Woo Chang
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea
- Brain Korea 21 PLUS Project for Medical Science and Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
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Pius-Sadowska E, Kawa MP, Kłos P, Rogińska D, Rudnicki M, Boehlke M, Waloszczyk P, Machaliński B. Alteration of Selected Neurotrophic Factors and their Receptor Expression in Mouse Brain Response to Whole-Brain Irradiation. Radiat Res 2016; 186:489-507. [DOI: 10.1667/rr14457.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Nikolakopoulou AM, Georgakopoulos A, Robakis NK. Presenilin 1 promotes trypsin-induced neuroprotection via the PAR2/ERK signaling pathway. Effects of presenilin 1 FAD mutations. Neurobiol Aging 2016; 42:41-9. [PMID: 27143420 PMCID: PMC4857890 DOI: 10.1016/j.neurobiolaging.2016.02.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 02/22/2016] [Accepted: 02/25/2016] [Indexed: 11/18/2022]
Abstract
Mutants of presenilin 1 (PS1) increase neuronal cell death causing autosomal-dominant familial Alzheimer's disease (FAD). Recent literature shows that treatment of neuronal cultures with low concentrations of trypsin, a member of the serine family of proteases, protects neurons from toxic insults by binding to the proteinase-activated receptor 2 and stimulating survival kinase extracellular signal-regulated kinase (ERK 1/2). Other studies show that PS1 is necessary for the neuroprotective activity of specific neurotrophic factors, such as brain-derived neurotrophic factor, against excitotoxicity and oxidative stress. Here, we show that treatment of mouse cortical neuronal cultures with trypsin activates ERK1/2 and protects neurons against glutamate excitoxicity. The trypsin-dependent ERK activation and neuroprotection requires both alleles of PS1 because neither PS1 knockout nor PS1 hemizygous neuronal cultures can use exogenous trypsin to activate ERK1/2 or increase neuronal survival. The protective effect of PS1 does not depend on its γ-secretase activity because inhibitors of γ-secretase have no effect on trypsin-mediated neuroprotection. Importantly, cortical neuronal cultures either heterozygous or homozygous for PS1 FAD mutants are unable to use trypsin to activate ERK1/2 and rescue neurons from excitotoxicity, indicating that FAD mutants inhibit trypsin-dependent neuroprotection in an autosomal-dominant manner. Furthermore, our data support the theory that PS FAD mutants increase neurodegeneration by inhibiting the ability of neurons to use cellular factors as protective agents against toxic insults.
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Affiliation(s)
- Angeliki M Nikolakopoulou
- Department of Psychiatry, Center for Molecular Biology and Genetics of Neurodegeneration, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Neuroscience, Center for Molecular Biology and Genetics of Neurodegeneration, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Anastasios Georgakopoulos
- Department of Psychiatry, Center for Molecular Biology and Genetics of Neurodegeneration, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Neuroscience, Center for Molecular Biology and Genetics of Neurodegeneration, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Nikolaos K Robakis
- Department of Psychiatry, Center for Molecular Biology and Genetics of Neurodegeneration, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Neuroscience, Center for Molecular Biology and Genetics of Neurodegeneration, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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Casamassa A, La Rocca C, Sokolow S, Herchuelz A, Matarese G, Annunziato L, Boscia F. Ncx3 gene ablation impairs oligodendrocyte precursor response and increases susceptibility to experimental autoimmune encephalomyelitis. Glia 2016; 64:1124-37. [DOI: 10.1002/glia.22985] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 02/29/2016] [Accepted: 03/07/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Antonella Casamassa
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine; Federico II University of Naples; Napoli 80131 Italy
| | - Claudia La Rocca
- Laboratorio di Immunologia, Istituto di Endocrinologia e Oncologia Sperimentale, Consiglio Nazionale delle Ricerche (IEOS-CNR); Napoli Italy
| | | | - Andre Herchuelz
- Laboratory of Pharmacology and Therapeutics, Université Libre de Bruxelles; Brussels Gosselies 6041 Belgium
| | - Giuseppe Matarese
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche; Università di Napoli “Federico II”; Napoli Italy
| | - Lucio Annunziato
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine; Federico II University of Naples; Napoli 80131 Italy
- Fondazione IRCSS SDN; Naples Italy
| | - Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine; Federico II University of Naples; Napoli 80131 Italy
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Varnum MM, Kiyota T, Ingraham KL, Ikezu S, Ikezu T. The anti-inflammatory glycoprotein, CD200, restores neurogenesis and enhances amyloid phagocytosis in a mouse model of Alzheimer's disease. Neurobiol Aging 2015; 36:2995-3007. [PMID: 26315370 DOI: 10.1016/j.neurobiolaging.2015.07.027] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 07/13/2015] [Accepted: 07/28/2015] [Indexed: 12/20/2022]
Abstract
Cluster of Differentiation-200 (CD200) is an anti-inflammatory glycoprotein expressed in neurons, T cells, and B cells, and its receptor is expressed on glia. Both Alzheimer's disease patients and mouse models display age-related or amyloid-β peptide (Aβ)-induced reductions in CD200. The goal of this study was to determine if neuronal CD200 expression restores hippocampal neurogenesis and reduces Aβ in the amyloid precursor protein mouse model. Amyloid precursor protein and wild-type mice were injected at 6 months of age with an adeno-associated virus expressing CD200 into the hippocampus and sacrificed at 12 months. CD200 expression restored neural progenitor cell proliferation and differentiation in the subgranular and granular cell layers of the dentate gyrus and reduced diffuse but not thioflavin-S(+) plaques in the hippocampus. In vitro studies demonstrated that CD200-stimulated microglia increased neural differentiation of neural stem cells and enhanced axon elongation and dendrite number. CD200 also enhanced Aβ uptake by microglia. These data indicate that CD200 is capable of enhancing microglia-mediated Aβ clearance and neural differentiation and has potential as a therapeutic for Alzheimer's disease.
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Affiliation(s)
- Megan M Varnum
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - Tomomi Kiyota
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Kaitlin L Ingraham
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - Seiko Ikezu
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - Tsuneya Ikezu
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA; Department of Neurology, Boston University School of Medicine, Boston, MA, USA.
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Schallner N, Pandit R, LeBlanc R, Thomas AJ, Ogilvy CS, Zuckerbraun BS, Gallo D, Otterbein LE, Hanafy KA. Microglia regulate blood clearance in subarachnoid hemorrhage by heme oxygenase-1. J Clin Invest 2015; 125:2609-25. [PMID: 26011640 DOI: 10.1172/jci78443] [Citation(s) in RCA: 153] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 04/27/2015] [Indexed: 12/25/2022] Open
Abstract
Subarachnoid hemorrhage (SAH) carries a 50% mortality rate. The extravasated erythrocytes that surround the brain contain heme, which, when released from damaged red blood cells, functions as a potent danger molecule that induces sterile tissue injury and organ dysfunction. Free heme is metabolized by heme oxygenase (HO), resulting in the generation of carbon monoxide (CO), a bioactive gas with potent immunomodulatory capabilities. Here, using a murine model of SAH, we demonstrated that expression of the inducible HO isoform (HO-1, encoded by Hmox1) in microglia is necessary to attenuate neuronal cell death, vasospasm, impaired cognitive function, and clearance of cerebral blood burden. Initiation of CO inhalation after SAH rescued the absence of microglial HO-1 and reduced injury by enhancing erythrophagocytosis. Evaluation of correlative human data revealed that patients with SAH have markedly higher HO-1 activity in cerebrospinal fluid (CSF) compared with that in patients with unruptured cerebral aneurysms. Furthermore, cisternal hematoma volume correlated with HO-1 activity and cytokine expression in the CSF of these patients. Collectively, we found that microglial HO-1 and the generation of CO are essential for effective elimination of blood and heme after SAH that otherwise leads to neuronal injury and cognitive dysfunction. Administration of CO may have potential as a therapeutic modality in patients with ruptured cerebral aneurysms.
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20
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Curcio M, Salazar IL, Inácio AR, Duarte EP, Canzoniero LMT, Duarte CB. Brain ischemia downregulates the neuroprotective GDNF-Ret signaling by a calpain-dependent mechanism in cultured hippocampal neurons. Cell Death Dis 2015; 6:e1645. [PMID: 25675305 PMCID: PMC4669807 DOI: 10.1038/cddis.2014.578] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 10/08/2014] [Accepted: 11/14/2014] [Indexed: 01/07/2023]
Abstract
The glial cell line-derived neurotrophic factor (GDNF) has an important role in neuronal survival through binding to the GFRα1 (GDNF family receptor alpha-1) receptor and activation of the receptor tyrosine kinase Ret. Transient brain ischemia alters the expression of the GDNF signaling machinery but whether the GDNF receptor proteins are also affected, and the functional consequences, have not been investigated. We found that excitotoxic stimulation of cultured hippocampal neurons leads to a calpain-dependent downregulation of the long isoform of Ret (Ret51), but no changes were observed for Ret9 or GFRα1 under the same conditions. Cleavage of Ret51 by calpains was selectively mediated by activation of the extrasynaptic pool of N-methyl-d-aspartate receptors and leads to the formation of a stable cleavage product. Calpain-mediated cleavage of Ret51 was also observed in hippocampal neurons subjected to transient oxygen and glucose deprivation (OGD), a model of global brain ischemia, as well as in the ischemic region in the cerebral cortex of mice exposed to transient middle cerebral artery occlusion. Although the reduction of Ret51 protein levels decreased the total GDNF-induced receptor activity (as determined by assessing total phospho-Ret51 protein levels) and their downstream signaling activity, the remaining receptors still showed an increase in phosphorylation after incubation of hippocampal neurons with GDNF. Furthermore, GDNF protected hippocampal neurons when present before, during or after OGD, and the effects under the latter conditions were more significant in neurons transfected with human Ret51. These results indicate that the loss of Ret51 in brain ischemia partially impairs the neuroprotective effects of GDNF.
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Affiliation(s)
- M Curcio
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra 3004-504, Portugal
- Department of Science and Technology, University of Sannio, Benevento 82100, Italy
| | - I L Salazar
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra 3004-504, Portugal
- Doctoral Programme in Experimental Biology and Biomedicine, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute for Interdisciplinary Research, University of Coimbra (IIIUC), Coimbra, Portugal
| | - A R Inácio
- Wallenberg Neuroscience Center, Lund University, Lund 221 84, Sweden
| | - E P Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra 3004-504, Portugal
- Department of Life Sciences, University of Coimbra, Coimbra 3004-517, Portugal
| | - L M T Canzoniero
- Department of Science and Technology, University of Sannio, Benevento 82100, Italy
| | - C B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra 3004-504, Portugal
- Department of Life Sciences, University of Coimbra, Coimbra 3004-517, Portugal
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Abstract
Brain injury continues to be one of the leading causes of disability worldwide. Despite decades of research, there is currently no pharmacologically effective treatment for preventing neuronal loss and repairing the brain. As a result, novel therapeutic approaches, such as cell-based therapies, are being actively pursued to repair tissue damage and restore neurological function after injury. In this study, we examined the neuroprotective potential of amniotic fluid (AF) single cell clones, engineered to secrete glial cell derived neurotrophic factor (AF-GDNF), both in vitro and in a surgically induced model of brain injury. Our results show that pre-treatment with GDNF significantly increases cell survival in cultures of AF cells or cortical neurons exposed to hydrogen peroxide. Since improving the efficacy of cell transplantation depends on enhanced graft cell survival, we investigated whether AF-GDNF cells seeded on polyglycolic acid (PGA) scaffolds could enhance graft survival following implantation into the lesion cavity. Encouragingly, the AF-GDNF cells survived longer than control AF cells in serum-free conditions and continued to secrete GDNF both in vitro and following implantation into the injured motor cortex. AF-GDNF implantation in the acute period following injury was sufficient to activate the MAPK/ERK signaling pathway in host neural cells in the peri-lesion area, potentially boosting endogenous neuroprotective pathways. These results were complemented with promising trends in beam walk tasks in AF-GDNF/PGA animals during the 7 day timeframe. Further investigation is required to determine whether significant behavioural improvement can be achieved at a longer timeframe.
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Fuqua JL, Littrell OM, Lundblad M, Turchan-Cholewo J, Abdelmoti LG, Galperin E, Bradley LH, Cass WA, Gash DM, Gerhardt GA. Dynamic changes in dopamine neuron function after DNSP-11 treatment: effects in vivo and increased ERK 1/2 phosphorylation in vitro. Peptides 2014; 54:1-8. [PMID: 24406899 PMCID: PMC3989369 DOI: 10.1016/j.peptides.2013.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 12/09/2013] [Accepted: 12/10/2013] [Indexed: 12/14/2022]
Abstract
Glial cell-line derived neurotrophic factor (GDNF) has demonstrated robust effects on dopamine (DA) neuron function and survival. A post-translational processing model of the human GDNF proprotein theorizes the formation of smaller, amidated peptide(s) from the proregion that exhibit neurobiological function, including an 11-amino-acid peptide named dopamine neuron stimulating peptide-11 (DNSP-11). A single treatment of DNSP-11 was delivered to the substantia nigra in the rat to investigate effects on DA-neuron function. Four weeks after treatment, potassium (K+) and D-amphetamine evoked DA release were studied in the striatum using microdialysis. There were no significant changes in DA-release after DNSP-11 treatment determined by microdialysis. Dopamine release was further examined in discrete regions of the striatum using high-speed chronoamperometry at 1-, 2-, and 4-weeks after DNSP-11 treatment. Two weeks after DNSP-11 treatment, potassium-evoked DA release was increased in specific subregions of the striatum. However, spontaneous locomotor activity was unchanged by DNSP-11 treatment. In addition, we show that a single treatment of DNSP-11 in the MN9D dopaminergic neuronal cell line results in phosphorylation of ERK1/2, which suggests a novel cellular mechanism responsible for increases in DA function.
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Affiliation(s)
- Joshua L Fuqua
- Department of Anatomy and Neurobiology, Parkinson's Disease Translational Center of Excellence, University of Kentucky Medical Center, MN 206 Medical Sciences Building, 800 Rose St., Lexington, KY 40536, USA
| | - Ofelia M Littrell
- Department of Anatomy and Neurobiology, Parkinson's Disease Translational Center of Excellence, University of Kentucky Medical Center, MN 206 Medical Sciences Building, 800 Rose St., Lexington, KY 40536, USA
| | - Martin Lundblad
- Experimental Medical Science, Neurobiology, Lund University, BMCA11, 221, 84 Lund, Sweden
| | - Jadwiga Turchan-Cholewo
- Department of Anatomy and Neurobiology, Parkinson's Disease Translational Center of Excellence, University of Kentucky Medical Center, MN 206 Medical Sciences Building, 800 Rose St., Lexington, KY 40536, USA
| | - Lina G Abdelmoti
- Department of Molecular & Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY, USA; Center of Structural Biology, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Emilia Galperin
- Department of Molecular & Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY, USA; Center of Structural Biology, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Luke H Bradley
- Department of Anatomy and Neurobiology, Parkinson's Disease Translational Center of Excellence, University of Kentucky Medical Center, MN 206 Medical Sciences Building, 800 Rose St., Lexington, KY 40536, USA; Department of Molecular & Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY, USA; Center of Structural Biology, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Wayne A Cass
- Department of Anatomy and Neurobiology, Parkinson's Disease Translational Center of Excellence, University of Kentucky Medical Center, MN 206 Medical Sciences Building, 800 Rose St., Lexington, KY 40536, USA
| | - Don M Gash
- Department of Anatomy and Neurobiology, Parkinson's Disease Translational Center of Excellence, University of Kentucky Medical Center, MN 206 Medical Sciences Building, 800 Rose St., Lexington, KY 40536, USA
| | - Greg A Gerhardt
- Department of Anatomy and Neurobiology, Parkinson's Disease Translational Center of Excellence, University of Kentucky Medical Center, MN 206 Medical Sciences Building, 800 Rose St., Lexington, KY 40536, USA.
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Li ZH, Li W, Shi JL, Tang MK. Nardosinone improves the proliferation, migration and selective differentiation of mouse embryonic neural stem cells. PLoS One 2014; 9:e91260. [PMID: 24614893 PMCID: PMC3948776 DOI: 10.1371/journal.pone.0091260] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Accepted: 02/10/2014] [Indexed: 11/18/2022] Open
Abstract
In this study, we investigated the impact of Nardosinone, a bioactive component in Nardostachys root, on the proliferation and differentiation of neural stem cells. The neural stem cells were isolated from cerebrums of embryonic day 14 CD1 mice. The proliferation of cells was monitored using the cell counting kit-8 assay, bromodeoxyuridine incorporation and cell cycle analysis. Cell migration and differentiation were investigated with the neurosphere assay and cell specific markers, respectively. The results showed that Nardosinone promotes cells proliferation and increases cells migration distance in a dose-dependent manner. Nardosinone also induces the selective differentiation of neural stem cells to neurons and oligodendrocytes, as indicated by the expression of microtubule-associated protein-2 and myelin basic protein, respectively. Nardosinone also increases the expression of phospho-extracellular signal-regulated kinase and phospho-cAMP response element binding protein during proliferation and differentiation. In conclusion, this study reveals the regulatory effects of Nardosinone on neural stem cells, which may have significant implications for the treatment of brain injury and neurodegenerative diseases.
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Affiliation(s)
- Ze-Hui Li
- Department of Biomedical Science, College of Medicine, University of Toledo, Toledo, Ohio, United States of America
- Department of Pharmacology, Beijing University of Chinese Medicine, Beijing, China
| | - Wei Li
- Department of Pharmacology, Beijing University of Chinese Medicine, Beijing, China
| | - Jin-Li Shi
- Department of Pharmacology, Beijing University of Chinese Medicine, Beijing, China
| | - Min-Ke Tang
- Department of Pharmacology, Beijing University of Chinese Medicine, Beijing, China
- * E-mail:
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Zlotnik A, Spittau B. GDNF fails to inhibit LPS-mediated activation of mouse microglia. J Neuroimmunol 2014; 270:22-8. [PMID: 24655425 DOI: 10.1016/j.jneuroim.2014.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 12/16/2013] [Accepted: 03/03/2014] [Indexed: 01/04/2023]
Abstract
GDNF is a potent neuroprotective factor for midbrain dopaminergic (mDA) neurons. In LPS-mediated models for mDA degeneration GDNF increases neuron survival and further reduces microglia activation. To elucidate the effects of GDNF on LPS-induced activation, primary microglia from C57BL/6 and NMRI mice have been analysed. In this study we demonstrate that GDNF is not able to inhibit LPS-mediated upregulation and release of the proinflammatory factors IL6 and TNFα. Moreover, we provide evidence that mouse microglia, in contrast to rat microglia, lack expression of the GDNF signalling receptor c-Ret resulting in abrogated activation of downstream signalling kinases Akt and Erk1/2.
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Affiliation(s)
- Anke Zlotnik
- Institute for Anatomy and Cell Biology, Department of Molecular Embryology, Albert-Ludwigs-University Freiburg, Germany
| | - Björn Spittau
- Institute for Anatomy and Cell Biology, Department of Molecular Embryology, Albert-Ludwigs-University Freiburg, Germany.
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Ortuño-Sahagún D, González RM, Verdaguer E, Huerta VC, Torres-Mendoza BM, Lemus L, Rivera-Cervantes MC, Camins A, Zárate CB. Glutamate excitotoxicity activates the MAPK/ERK signaling pathway and induces the survival of rat hippocampal neurons in vivo. J Mol Neurosci 2013; 52:366-77. [PMID: 24190281 DOI: 10.1007/s12031-013-0157-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 10/18/2013] [Indexed: 11/25/2022]
Abstract
Current knowledge concerning the molecular mechanisms of the cellular response to excitotoxic insults in neurodegenerative diseases is insufficient. Although glutamate (Glu) has been widely studied as the main excitatory neurotransmitter and principal excitotoxic agent, the neuroprotective response enacted by neurons is not yet completely understood. Some of the molecular participants have been revealed, but the signaling pathways involved in this protective response are just beginning to be identified. Here, we demonstrate in vivo that, in response to the cell damage and death induced by Glu excitotoxicity, neurons orchestrate a survival response through the extracellular signal-regulated kinase (ERK) signaling pathway by increasing ERK expression in the rat hippocampal (CA1) region, allowing increased neuronal survival. In addition, this protective response is specifically reversed by U0126, an ERK inhibitor, which promotes cell death only when it is administered together with Glu. Our findings demonstrate that the ERK signaling pathway has a neuroprotective role in the response to Glu-induced excitotoxicity in hippocampal neurons. Therefore, the ERK signaling pathway may be activated as a cellular response to excitotoxic injury to prevent damage and neural loss, representing a novel therapeutic target in the treatment of neurodegenerative diseases.
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Affiliation(s)
- Daniel Ortuño-Sahagún
- Laboratorio de Desarrollo y Regeneración Neural, Instituto de Neurobiología, Departamento de Biología Celular y Molecular, CUCBA, Universidad de Guadalajara, Camino Ing. R. Padilla Sánchez, 2100, Las Agujas, Zapopan, 44600, Jalisco, Mexico
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Yang L, Yue N, Zhu X, Han Q, Liu Q, Yu J, Wu G. Electroacupuncture upregulates ERK signaling pathways and promotes adult hippocampal neural progenitors proliferation in a rat model of depression. Altern Ther Health Med 2013; 13:288. [PMID: 24165147 PMCID: PMC3813990 DOI: 10.1186/1472-6882-13-288] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 10/23/2013] [Indexed: 02/04/2023]
Abstract
Background In this study, we investigate the proliferation of adult neural stem cells (NSCs) in a chronic unpredictable stress (CUS) rat model of depression, the effects of electroacupunture (EA) on depressive-like symptoms and the corresponding signaling pathways. Methods SD rats were subjected to 4 weeks of CUS to induce depressive-like behaviors. EA was performed at the Du-20 (Bai-Hui) and GB-34 (Yang-Ling-Quan) acupoints. Rats were injected with BrdU and the brains were cut into sections. Double-labeling with BrdU/Sox2 and p-ERK/Nestin was performed to demonstrate the in vivo proliferation of adult NSCs in hippocampus and ERK activation in NSCs. Hippocampal microdialysates of different groups were collected to observe the in vitro effects on NSCs. Results After 8 treatments, EA generated a clear antidepressant effect on the stressed rats and promoted the NSC proliferation. ERK activation might be involved in the antidepressant-like effects of EA treatment. Hippocampal microdialysates from EA-treated stressed rats influenced NSCs to form larger neural spheres and exhibit higher p-ERK level in vitro, compared to the untreated stressed rats. Meanwhile, the antidepressant-like effects of EA involved contribution from both acupoint specificity and electrical stimulus. Conclusions EA might interfere with the hippocampal microenvironment and enhance the activation of ERK signaling pathways. This could mediate, at least in part, the beneficial effects of EA on NSC proliferation and depressive-like behaviors.
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Calabresi P, Castrioto A, Di Filippo M, Picconi B. New experimental and clinical links between the hippocampus and the dopaminergic system in Parkinson's disease. Lancet Neurol 2013; 12:811-21. [DOI: 10.1016/s1474-4422(13)70118-2] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Ionic transporter activity in astrocytes, microglia, and oligodendrocytes during brain ischemia. J Cereb Blood Flow Metab 2013; 33:969-82. [PMID: 23549380 PMCID: PMC3705429 DOI: 10.1038/jcbfm.2013.44] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 02/27/2013] [Accepted: 02/28/2013] [Indexed: 01/09/2023]
Abstract
Glial cells constitute a large percentage of cells in the nervous system. During recent years, a large number of studies have critically attributed to glia a new role which no longer reflects the long-held view that glia constitute solely a silent and passive supportive scaffolding for brain cells. Indeed, it has been hypothesized that glia, partnering neurons, have a much more actively participating role in brain function. Alteration of intraglial ionic homeostasis in response to ischemic injury has a crucial role in inducing and maintaining glial responses in the ischemic brain. Therefore, glial transporters as potential candidates in stroke intervention are becoming promising targets to enhance an effective and additional therapy for brain ischemia. In this review, we will describe in detail the role played by ionic transporters in influencing astrocyte, microglia, and oligodendrocyte activity and the implications that these transporters have in the progression of ischemic lesion.
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Abstract
White matter neurons in multiple sclerosis brains are destroyed during demyelination and then replaced in some chronic multiple sclerosis lesions that exhibit a morphologically distinct population of activated microglia [Chang A, et al. (2008) Brain 131(Pt 9):2366-2375]. Here we investigated whether activated microglia secrete factors that promote the generation of neurons from white matter cells. Adult rat brain microglia (resting or activated with lipopolysaccharide) were isolated by flow cytometry and cocultured with neonatal rat optic nerve cells in separate but media-connected chambers. Optic nerve cells cocultured with activated microglia showed a significant increase in the number of cells of neuronal phenotype, identified by neuron-specific class III beta-tubulin (TUJ-1) labeling, compared with cultures with resting microglia. To investigate the possible source of the TUJ-1-positive cells, A2B5-positive oligodendrocyte progenitor cells and A2B5-negative cells were isolated and cocultured with resting and activated microglia. Significantly more TUJ-1-positive cells were generated from A2B5-negative cells (∼70%) than from A2B5-positive cells (~30%). Mass spectrometry analysis of microglia culture media identified protease serine 2 (PRSS2) as a factor secreted by activated, but not resting, microglia. When added to optic nerve cultures, PRSS2 significantly increased neurogenesis, whereas the serine protease inhibitor, secretory leukocyte protease inhibitor, decreased activated microglia-induced neurogenesis. Collectively our data provide evidence that activated microglia increase neurogenesis through secretion of PRSS2.
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Boscia F, Esposito CL, Casamassa A, de Franciscis V, Annunziato L, Cerchia L. The isolectin IB4 binds RET receptor tyrosine kinase in microglia. J Neurochem 2013; 126:428-36. [PMID: 23413818 DOI: 10.1111/jnc.12209] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 02/07/2013] [Accepted: 02/08/2013] [Indexed: 02/01/2023]
Abstract
Ret receptor tyrosine kinase is the signaling component of the receptor complex for the family ligands of the glial cell line-derived neurotrophic factor (GDNF). Ret is involved in the development of enteric nervous system, of sympathetic, parasympathetic, motor and sensory neurons, and it is necessary for the post-natal maintenance of dopaminergic neurons. Ret expression has been as well demonstrated on microglia and several evidence indicate that GDNF regulates not only neuronal survival and maturation but also certain functions of microglia in the brain. Here, we demonstrated that the plant lectin Griffonia (Bandeiraea) simplicifolia lectin I, isolectin B4 (IB4), commonly used as a microglial marker in the brain, binds to the glycosylated extracellular domain of Ret on the surface of living NIH3T3 fibroblasts cells stably transfected with Ret as well as in adult rat brain as revealed by immunoblotting. Furthermore, confocal immunofluorescence analysis demonstrated a clear overlap in staining between pRet and IB4 in primary microglia cultures as well as in adult rat sections obtained from control or post-ischemic brain after permanent middle artery occlusion (pMCAO). Interestingly, IB4 staining identified activated or ameboid Ret-expressing microglia under ischemic conditions. Collectively, our data indicate Ret receptor as one of the IB4-reactive glycoconjugate accounting for the IB4 stain in microglia under physiological and ischemic conditions.
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Affiliation(s)
- Francesca Boscia
- Dipartimento di Neuroscienze, Sezione di Farmacologia, Facolta' di Medicina e Chirurgia, Universita' degli Studi di Napoli Federico II, Naples, Italy
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Wong WT. Microglial aging in the healthy CNS: phenotypes, drivers, and rejuvenation. Front Cell Neurosci 2013; 7:22. [PMID: 23493481 PMCID: PMC3595516 DOI: 10.3389/fncel.2013.00022] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Accepted: 02/21/2013] [Indexed: 12/12/2022] Open
Abstract
Neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and age-related macular degeneration (AMD), share two characteristics in common: (1) a disease prevalence that increases markedly with advancing age, and (2) neuroinflammatory changes in which microglia, the primary resident immune cell of the CNS, feature prominently. These characteristics have led to the hypothesis that pathogenic mechanisms underlying age-related neurodegenerative disease involve aging changes in microglia. If correct, targeting features of microglial senescence may constitute a feasible therapeutic strategy. This review explores this hypothesis and its implications by considering the current knowledge on how microglia undergo change during aging and how the emergence of these aging phenotypes relate to significant alterations in microglial function. Evidence and theories on cellular mechanisms implicated in driving senescence in microglia are reviewed, as are “rejuvenative” measures and strategies that aim to reverse or ameliorate the aging microglial phenotype. Understanding and controlling microglial aging may represent an opportunity for elucidating disease mechanisms and for formulating novel therapies.
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Affiliation(s)
- Wai T Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health Bethesda, MD, USA
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Wang J, Yang Z, Liu C, Zhao Y, Chen Y. Activated microglia provide a neuroprotective role by balancing glial cell-line derived neurotrophic factor and tumor necrosis factor-α secretion after subacute cerebral ischemia. Int J Mol Med 2012; 31:172-8. [PMID: 23151666 PMCID: PMC3573737 DOI: 10.3892/ijmm.2012.1179] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Accepted: 10/17/2012] [Indexed: 02/05/2023] Open
Abstract
Microglia are the major immune cells in the central nervous system and play a key role in brain injury pathology. However, the role of activated microglia after subacute cerebral ischemia (SCI) remains unknown. To address this issue, we established a permanent middle cerebral artery occlusion (pMCAO) rat model and treated pMCAO rats with N-(6-oxo-5,6-dihydro-phenanthridin-2-yl)-N,N-dimethylacetamide (PJ34) (an inhibitor of microglial activation), or with vehicle alone. Finally, we determined the differences between the PJ34-and vehicle-treated rats with respect to neurological deficits, infarct volume, neuronal loss and the expression of CD11b (a marker of microglial activation), glial cell line-derived neurotrophic factor (GDNF) and tumor necrosis factor-α (TNF-α) at 1, 3 and 7 days after treatment. We found that the PJ34-treated rats had more severe neurological deficits and a larger infarct volume and exhibited a decreased CD11b expression, more neuronal loss, decreased expression of GDNF mRNA and protein but increased expression of TNF-α mRNA and protein compared with the vehicle-treated rats at 3 and 7 days after treatment. These results indicate that activated microglia provide a neuroprotective role through balancing GDNF and TNF-α expression following SCI.
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Affiliation(s)
- Jianping Wang
- Department of Neurology, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, PR China
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Rocha SM, Cristovão AC, Campos FL, Fonseca CP, Baltazar G. Astrocyte-derived GDNF is a potent inhibitor of microglial activation. Neurobiol Dis 2012; 47:407-15. [DOI: 10.1016/j.nbd.2012.04.014] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 03/29/2012] [Accepted: 04/26/2012] [Indexed: 12/14/2022] Open
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Esposito F, Boscia F, Gigantino V, Tornincasa M, Fusco A, Franco R, Chieffi P. The high-mobility group A1-estrogen receptor β nuclear interaction is impaired in human testicular seminomas. J Cell Physiol 2012; 227:3749-55. [DOI: 10.1002/jcp.24087] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abstract
The glial cell line-derived neurotrophic factor (GDNF) was first identified as a survival factor for midbrain dopaminergic neurons, but additional studies provided evidences for a role as a trophic factor for other neurons of the central and peripheral nervous systems. GDNF regulates cellular activity through interaction with glycosyl-phosphatidylinositol-anchored cell surface receptors, GDNF family receptor-α1, which might signal through the transmembrane Ret tyrosine receptors or the neural cell adhesion molecule, to promote cell survival, neurite outgrowth, and synaptogenesis. The neuroprotective effect of exogenous GDNF has been shown in different experimental models of focal and global brain ischemia, by local administration of the trophic factor, using viral vectors carrying the GDNF gene and by transplantation of GDNF-expressing cells. These different strategies and the mechanisms contributing to neuroprotection by GDNF are discussed in this review. Importantly, neuroprotection by GDNF was observed even when administered after the ischemic injury.
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Affiliation(s)
- Emília P Duarte
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, Coimbra, Portugal
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Shi GX, Andres DA, Cai W. Ras family small GTPase-mediated neuroprotective signaling in stroke. Cent Nerv Syst Agents Med Chem 2012; 11:114-37. [PMID: 21521171 DOI: 10.2174/187152411796011349] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 01/18/2011] [Accepted: 03/22/2011] [Indexed: 12/31/2022]
Abstract
Selective neuronal cell death is one of the major causes of neuronal damage following stroke, and cerebral cells naturally mobilize diverse survival signaling pathways to protect against ischemia. Importantly, therapeutic strategies designed to improve endogenous anti-apoptotic signaling appear to hold great promise in stroke treatment. While a variety of complex mechanisms have been implicated in the pathogenesis of stroke, the overall mechanisms governing the balance between cell survival and death are not well-defined. Ras family small GTPases are activated following ischemic insults, and in turn, serve as intrinsic switches to regulate neuronal survival and regeneration. Their ability to integrate diverse intracellular signal transduction pathways makes them critical regulators and potential therapeutic targets for neuronal recovery after stroke. This article highlights the contribution of Ras family GTPases to neuroprotective signaling cascades, including mitogen-activated protein kinase (MAPK) family protein kinase- and AKT/PKB-dependent signaling pathways as well as the regulation of cAMP response element binding (CREB), Forkhead box O (FoxO) and hypoxiainducible factor 1(HIF1) transcription factors, in stroke.
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Affiliation(s)
- Geng-Xian Shi
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, 741 S. Limestone St., Lexington, KY 40536-0509, USA.
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Vinet J, Weering HRJV, Heinrich A, Kälin RE, Wegner A, Brouwer N, Heppner FL, Rooijen NV, Boddeke HWGM, Biber K. Neuroprotective function for ramified microglia in hippocampal excitotoxicity. J Neuroinflammation 2012; 9:27. [PMID: 22293457 PMCID: PMC3292937 DOI: 10.1186/1742-2094-9-27] [Citation(s) in RCA: 200] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 01/31/2012] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Most of the known functions of microglia, including neurotoxic and neuroprotective properties, are attributed to morphologically-activated microglia. Resting, ramified microglia are suggested to primarily monitor their environment including synapses. Here, we show an active protective role of ramified microglia in excitotoxicity-induced neurodegeneration. METHODS Mouse organotypic hippocampal slice cultures were treated with N-methyl-D-aspartic acid (NMDA) to induce excitotoxic neuronal cell death. This procedure was performed in slices containing resting microglia or slices that were chemically or genetically depleted of their endogenous microglia. RESULTS Treatment of mouse organotypic hippocampal slice cultures with 10-50 μM N-methyl-D-aspartic acid (NMDA) induced region-specific excitotoxic neuronal cell death with CA1 neurons being most vulnerable, whereas CA3 and DG neurons were affected less. Ablation of ramified microglia severely enhanced NMDA-induced neuronal cell death in the CA3 and DG region rendering them almost as sensitive as CA1 neurons. Replenishment of microglia-free slices with microglia restored the original resistance of CA3 and DG neurons towards NMDA. CONCLUSIONS Our data strongly suggest that ramified microglia not only screen their microenvironment but additionally protect hippocampal neurons under pathological conditions. Morphological activation of ramified microglia is thus not required to influence neuronal survival.
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Affiliation(s)
- Jonathan Vinet
- Department of Neuroscience, Section Medical Physiology, University Medical Center Groningen (UMCG), Rijksuniversiteit Groningen (RUG), Groningen, The Netherlands
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Silencing or knocking out the Na(+)/Ca(2+) exchanger-3 (NCX3) impairs oligodendrocyte differentiation. Cell Death Differ 2011; 19:562-72. [PMID: 21959935 DOI: 10.1038/cdd.2011.125] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Changes in intracellular [Ca(2+)](i) levels have been shown to influence developmental processes that accompany the transition of human oligodendrocyte precursor cells (OPCs) into mature myelinating oligodendrocytes and are required for the initiation of the myelination and re-myelination processes. In the present study, we explored whether calcium signals mediated by the selective sodium calcium exchanger (NCX) family members NCX1, NCX2, and NCX3, play a role in oligodendrocyte maturation. Functional studies, as well as mRNA and protein expression analyses, revealed that NCX1 and NCX3, but not NCX2, were divergently modulated during OPC differentiation into oligodendrocyte phenotype. In fact, whereas NCX1 was downregulated, NCX3 was strongly upregulated during oligodendrocyte development. The importance of calcium signaling mediated by NCX3 during oligodendrocyte maturation was supported by several findings. Indeed, whereas knocking down the NCX3 isoform in OPCs prevented the upregulation of the myelin protein markers 2',3'-cyclic nucleotide-3'-phosphodiesterase (CNPase) and myelin basic protein (MBP), its overexpression induced an upregulation of CNPase and MBP. Furthermore, NCX3-knockout mice showed not only a reduced size of spinal cord but also marked hypo-myelination, as revealed by decrease in MBP expression and by an accompanying increase in OPC number. Collectively, our findings indicate that calcium signaling mediated by NCX3 has a crucial role in oligodendrocyte maturation and myelin formation.
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Abstract
Microglial cells are the resident macrophages in the central nervous system. These cells of mesodermal/mesenchymal origin migrate into all regions of the central nervous system, disseminate through the brain parenchyma, and acquire a specific ramified morphological phenotype termed "resting microglia." Recent studies indicate that even in the normal brain, microglia have highly motile processes by which they scan their territorial domains. By a large number of signaling pathways they can communicate with macroglial cells and neurons and with cells of the immune system. Likewise, microglial cells express receptors classically described for brain-specific communication such as neurotransmitter receptors and those first discovered as immune cell-specific such as for cytokines. Microglial cells are considered the most susceptible sensors of brain pathology. Upon any detection of signs for brain lesions or nervous system dysfunction, microglial cells undergo a complex, multistage activation process that converts them into the "activated microglial cell." This cell form has the capacity to release a large number of substances that can act detrimental or beneficial for the surrounding cells. Activated microglial cells can migrate to the site of injury, proliferate, and phagocytose cells and cellular compartments.
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Brain infiltration of leukocytes contributes to the pathophysiology of temporal lobe epilepsy. J Neurosci 2011; 31:4037-50. [PMID: 21411646 DOI: 10.1523/jneurosci.6210-10.2011] [Citation(s) in RCA: 195] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Clinical and experimental evidence indicates that inflammatory processes contribute to the pathophysiology of epilepsy, but underlying mechanisms remain mostly unknown. Using immunohistochemistry for CD45 (common leukocyte antigen) and CD3 (T-lymphocytes), we show here microglial activation and infiltration of leukocytes in sclerotic tissue from patients with mesial temporal lobe epilepsy (TLE), as well as in a model of TLE (intrahippocampal kainic acid injection), characterized by spontaneous, nonconvulsive focal seizures. Using specific markers of lymphocytes, microglia, macrophages, and neutrophils in kainate-treated mice, we investigated with pharmacological and genetic approaches the contribution of innate and adaptive immunity to kainate-induced inflammation and neurodegeneration. Furthermore, we used EEG analysis in mutant mice lacking specific subsets of lymphocytes to explore the significance of inflammatory processes for epileptogenesis. Blood-brain barrier disruption and neurodegeneration in the kainate-lesioned hippocampus were accompanied by sustained ICAM-1 upregulation, microglial cell activation, and infiltration of CD3(+) T-cells. Moreover, macrophage infiltration was observed, selectively in the dentate gyrus where prominent granule cell dispersion was evident. Unexpectedly, depletion of peripheral macrophages by systemic clodronate liposome administration affected granule cell survival. Neurodegeneration was aggravated in kainate-lesioned mice lacking T- and B-cells (RAG1-knock-out), because of delayed invasion by Gr-1(+) neutrophils. Most strikingly, these mutant mice exhibited early onset of spontaneous recurrent seizures, suggesting a strong impact of immune-mediated responses on network excitability. Together, the concerted action of adaptive and innate immunity triggered locally by intrahippocampal kainate injection contributes seizure-suppressant and neuroprotective effects, shedding new light on neuroimmune interactions in temporal lobe epilepsy.
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Malik S, Khalique H, Buch S, Seth P. A growth factor attenuates HIV-1 Tat and morphine induced damage to human neurons: implication in HIV/AIDS-drug abuse cases. PLoS One 2011; 6:e18116. [PMID: 21483469 PMCID: PMC3063804 DOI: 10.1371/journal.pone.0018116] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 02/25/2011] [Indexed: 01/03/2023] Open
Abstract
The neuropathological abnormalities of human immunodeficiency virus (HIV)-1 patients abusing illicit drugs suggest extensive interactions between the two agents, thereby leading to increased rate of progression to neurodegeneration. The role of HIV-1 transactivating protein, Tat has been elucidated in mediating neuronal damage via apoptosis, a hallmark of HIV-associated dementia (HAD), however the underlying mechanisms involved in enhanced neurodegeneration by illicit drugs remain elusive. In this study, we demonstrated that morphine enhances HIV-Tat induced toxicity in human neurons and neuroblastoma cells. Enhanced toxicity by Tat and morphine was accompanied by increased numbers of TUNEL positive apoptotic neurons, elevated caspase-3 levels and decreased ratio of anti- and pro-apoptotic proteins, Bcl2/Bax. Tat and morphine together elicited high levels of reactive oxygen species that were NADPH dependent. Significant alterations in mitochondrial membrane homeostasis were also observed with co-exposure of these agents. Extensive studies of mitogen activated protein kinase (MAPK) signaling pathways revealed the involvement of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase-1/2 (ERK1/2) pathways in enhanced toxicity of Tat and morphine. In addition to this, we found that pre-treatment of cells with platelet derived growth factor (PDGF-BB) protected neurons from HIV-Tat and morphine induced damage. PDGF-BB alleviated ROS production, maintained mitochondrial membrane potential, decreased caspase-3 activation and hence protected the cells from undergoing apoptosis. PDGF-BB mediated protection against Tat and morphine involved the phosphatidylinositol–3 kinase (PI3K) pathway, as specific inhibitor of PI3K abrogated the protection conferred by PDGF-BB. This study demonstrates the mechanism of enhanced toxicity in human neurons subjected to co-exposure of HIV protein Tat and morphine, thus implying its importance in HIV positive drug abusers, where damage to the brain is reported to be more severe than non-drug abusers. We have also showed for the first time that PDGF-BB can protect against simultaneous exposure of Tat and morphine, strengthening its role as a neuroprotective agent that could be considered for therapeutic intervention.
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Affiliation(s)
- Shaily Malik
- Cellular and Molecular Neuroscience, National Brain Research Center, Manesar, Gurgaon, Haryana, India
| | - Hena Khalique
- Cellular and Molecular Neuroscience, National Brain Research Center, Manesar, Gurgaon, Haryana, India
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Pankaj Seth
- Cellular and Molecular Neuroscience, National Brain Research Center, Manesar, Gurgaon, Haryana, India
- * E-mail:
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Schauwecker PE. Congenic strains provide evidence that a mapped locus on chromosome 15 influences excitotoxic cell death. GENES BRAIN AND BEHAVIOR 2010; 10:100-10. [PMID: 20807240 DOI: 10.1111/j.1601-183x.2010.00644.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inbred strains of mice differ in their susceptibility to excitotoxin-induced cell death, but the genetic basis of individual variation is unknown. Prior studies with crosses of the FVB/NJ (seizure-induced cell death susceptible) mouse and the seizure-induced cell death resistant mouse, C57BL/6J, showed the presence of three quantitative trait loci (QTLs), named seizure-induced cell death 1 (Sicd1) to Sicd3. To better localize and characterize the Sicd2 locus, two reciprocal congenic mouse strains were created. While the B6.FVB-Sicd2 congenic mouse was without effect on modifying susceptibility to seizure-induced excitotoxic cell death, the FVB.B6-Sicd2 congenic mouse, in which the chromosome (Chr) 15 region of C57BL/6J was introgressed into FVB/NJ, showed reduced seizure-induced excitotoxic cell death following kainate administration. Phenotypic comparison between FVB and the congenic FVB.B6-Sicd2 strain confirmed that the Sicd2 interval harbors gene(s) conferring strong protection against seizure-induced excitotoxic cell death. Interval-specific congenic lines (ISCLs) that encompass Sicd2 on Chr 15 were generated and were used to fine-map this QTL. Resultant progeny were treated with kainate and examined for the extent of seizure-induced cell death in order to deduce the Sicd2 genotypes of the recombinants through linkage analysis. All of the ISCLs exhibited reduced cell death associated with the C57BL/6J phenotype; however, ISCL-2 showed the most dramatic reduction in seizure-induced cell death in both area CA3 and in the dentate hilus. These findings confirm the existence of polymorphic loci within the reduced critical region of Sicd2 that regulate the severity of seizure-induced cell death.
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Affiliation(s)
- P E Schauwecker
- Department of Cell and Neurobiology, USC Keck School of Medicine, Los Angeles, CA 90089-9112, USA.
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Chang PY, Doppalapudi R, Bakke J, Wang A, Menda S, Davis Z. Biological impact of low dose-rate simulated solar particle event radiation in vivo. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2010; 49:379-388. [PMID: 20473680 DOI: 10.1007/s00411-010-0291-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 05/01/2010] [Indexed: 05/29/2023]
Abstract
C57Bl6-lacZ animals were exposed to a range of low dose-rate simulated solar particle event (sSPE) radiation at the NASA-sponsored Research Laboratory (NSRL) at Brookhaven National Laboratory (BNL). Peripheral blood was harvested from animals from 1 to 12 days after total body irradiation (TBI) to quantify the level of circulating reticulocytes (RET) and micronucleated reticulocytes (MN-RET) as an early indicator of radiation-induced genotoxicity. Bone marrow lymphocytes and hippocampal tissues from each animal were collected at 12 days and up to two months, to evaluate dose-dependent late effects after sSPE exposure. Early hematopoietic changes show that the % RET was reduced up to 3 days in response to radiation exposure but recovered at 12 days postirradiation. The % MN-RET in peripheral blood was temporally regulated and dependant on the total accumulated dose. Total chromosome aberrations in lymphocytes increased linearly with dose within a week after radiation and remained significantly higher than the control values at 4 weeks after exposure. The level of aberrations in the irradiated animals returned to control levels by 8 weeks postirradiation. Measurements of chromosome 2 and 8 specific aberrations indicate that, consistent with conventional giemsa-staining methods, the level of aberrations is also not significantly higher than in control animals at 8 weeks postirradiation. The hippocampus was surveyed for differential transcriptional regulation of genes known to be associated with neurogenesis. Our results showed differential expression of neurotrophin and their associated receptor genes within 1 week after sSPE exposure. Progressive changes in the profile of expressed genes known to be involved in neurogenic signaling pathways were dependent on the sSPE dose. Our results to date suggest that radiation-induced changes in the hematopoietic system, i.e., chromosome aberrations in lymphocytes, are transient and do not persist past 4 weeks after radiation. On the other hand, alteration in the profile of genes known to be involved in neurotrophic functions in the hippocampal tissue appears to persist for up to 8 weeks after radiation exposure. Such temporal changes confirm that, although cytogenetic changes after a single dose of low-dose and low-dose-rate protons appear to be transient, the impact of this exposure is sufficient to lead to persistent dynamic changes in neuronal tissues long after the initial radiation exposure.
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Affiliation(s)
- P Y Chang
- SRI International, PN175, 333 Ravenswood Ave, Menlo Park, CA 94025, USA.
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Chan SHH, Sun EYH, Chang AYW. Extracellular signal-regulated kinase 1/2 plays a pro-life role in experimental brain stem death via MAPK signal-interacting kinase at rostral ventrolateral medulla. J Biomed Sci 2010; 17:17. [PMID: 20226096 PMCID: PMC2848001 DOI: 10.1186/1423-0127-17-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Accepted: 03/15/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND As the origin of a life-and-death signal detected from systemic arterial pressure, which sequentially increases (pro-life) and decreases (pro-death) to reflect progressive dysfunction of central cardiovascular regulation during the advancement towards brain stem death in critically ill patients, the rostral ventrolateral medulla (RVLM) is a suitable neural substrate for mechanistic delineation of this fatal phenomenon. The present study assessed the hypothesis that extracellular signal-regulated kinase 1/2 (ERK1/2), a member of the mitogen-activated protein kinases (MAPKs) that is important for cell survival and is activated specifically by MAPK kinase 1/2 (MEK1/2), plays a pro-life role in RVLM during brain stem death. We further delineated the participation of MAPK signal-interacting kinase (MNK), a novel substrate of ERK in this process. METHODS An experimental model of brain stem death that employed microinjection of the organophosphate insecticide mevinphos (Mev; 10 nmol) bilaterally into RVLM of Sprague-Dawley rats was used, in conjunction with cardiovascular, pharmacological and biochemical evaluations. RESULTS Results from ELISA showed that whereas the total ERK1/2 was not affected, augmented phosphorylation of ERK1/2 at Thr202 and Tyr204 in RVLM occurred preferentially during the pro-life phase of experimental brain stem death. Furthermore, pretreatment by microinjection into the bilateral RVLM of a specific ERK2 inhibitor, ERK activation inhibitor peptide II (1 nmol); a specific MEK1/2 inhibitor, U0126 (5 pmol); or a specific MNK1/2 inhibitor, CGP57380 (5 pmol) exacerbated the hypotension and blunted the augmented life-and-death signals exhibited during the pro-life phase. Those pretreatments also blocked the upregulated nitric oxide synthase I (NOS I)/protein kinase G (PKG) signaling, the pro-life cascade that sustains central cardiovascular regulatory functions during experimental brain stem death. CONCLUSIONS Our results demonstrated that activation of MEK1/2, ERK1/2 and MNK1/2 in RVLM plays a preferential pro-life role by sustaining the central cardiovascular regulatory machinery during brain stem death via upregulation of NOS I/PKG signaling cascade in RVLM.
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Affiliation(s)
- Samuel H H Chan
- Center for Translational Research in Biomedical Sciences, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung County 83301, Taiwan
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