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Tronson NC, Collette KM. (Putative) sex differences in neuroimmune modulation of memory. J Neurosci Res 2017; 95:472-486. [PMID: 27870428 PMCID: PMC5120654 DOI: 10.1002/jnr.23921] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 08/11/2016] [Accepted: 08/22/2016] [Indexed: 12/11/2022]
Abstract
The neuroimmune system is significantly sexually dimorphic, with sex differences evident in the number and activation states of microglia, in the activation of astrocytes, and in cytokine release and function. Neuroimmune cells and signaling are now recognized as critical for many neural functions throughout the life span, including synaptic plasticity and memory function. Here we address the question of how cytokines, astrocytes, and microglia contribute to memory, and specifically how neuroimmune modulation of memory differentially affects males and females. Understanding sex differences in both normal memory processes and dysregulation of memory in psychiatric and neurological disorders is critical for developing treatment and preventive strategies for memory disorders that are effective for both men and women. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Natalie C Tronson
- Department of Psychology, University of Michigan, Ann Arbor, Michigan
| | - Katie M Collette
- Department of Psychology, University of Michigan, Ann Arbor, Michigan
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202
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Exploring New Inflammatory Biomarkers and Pathways during LPS-Induced M1 Polarization. Mediators Inflamm 2016; 2016:6986175. [PMID: 28096568 PMCID: PMC5209629 DOI: 10.1155/2016/6986175] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 10/18/2016] [Accepted: 11/07/2016] [Indexed: 12/25/2022] Open
Abstract
Identification of mediators triggering microglia activation and transference of noncoding microRNA (miRNA) into exosomes are critical to dissect the mechanisms underlying neurodegeneration. We used lipopolysaccharide- (LPS-) induced N9 microglia activation to explore new biomarkers/signaling pathways and to identify inflammatory miRNA (inflamma-miR) in cells and their derived exosomes. Upregulation of iNOS and MHC-II (M1-markers) and downregulation of arginase 1, FIZZ1 (M2-markers), and CX3CR1 (M0/M2 polarization) confirmed the switch of N9 LPS-treated cells into the M1 phenotype, as described for macrophages/microglia. Cells showed increased proliferation, activated TLR4/TLR2/NF-κB pathway, and enhanced phagocytosis, further corroborated by upregulated MFG-E8. We found NLRP3-inflammasome activation in these cells, probably accounting for the increased extracellular content of the cytokine HMGB1 and of the MMP-9 we have observed. We demonstrate for the first time that the inflamma-miR profiling (upregulated miR-155 and miR-146a plus downregulated miR-124) in M1 polarized N9 cells, noticed by others in activated macrophages/microglia, was replicated in their derived exosomes, likely regulating the inflammatory response of recipient cells and dissemination processes. Data show that LPS-treated N9 cells behave like M1 polarized microglia/macrophages, while providing new targets for drug discovery. In particular, the study yields novel insights into the exosomal circulating miRNA during neuroinflammation important for emerging therapeutic approaches targeting microglia activation.
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203
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Ikeda M, Hossain MI, Zhou L, Horie M, Ikenaka K, Horii A, Takebayashi H. Histological detection of dynamic glial responses in the dysmyelinating Tabby-jimpy mutant brain. Anat Sci Int 2016; 93:119-127. [PMID: 27888476 DOI: 10.1007/s12565-016-0383-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/11/2016] [Indexed: 11/27/2022]
Abstract
Oligodendrocytes (OLs) are glial cells that form myelin sheaths surrounding the axons in the central nervous system (CNS). Jimpy (jp) mutant mice are dysmyelinating disease models that show developmental abnormalities in myelinated OLs in the CNS. The causative gene in jp mice is the proteolipid protein (PLP) located on the X chromosome. Mutations in the jp allele result in exon 5 skipping and expression of abnormal PLP containing a C-terminal frame shift. Many lines of evidence suggest that abnormal PLP in OLs results in endoplasmic reticulum (ER) stress and cell death. To histologically detect glial responses in the jp mutant brain, we performed staining with lineage-specific markers. Using OL markers and OL progenitor cell marker staining, we identified reduced numbers of OL lineage cells in the jp mutant brain. Nuclear staining of the transcription factor Olig1 was observed in the Tabby-jp brain, whereas cytoplasmic Olig1 staining was observed in the wild-type brain at postnatal day 21, suggesting that active myelination was present in the mutant brain. Many microglial cells with activated morphology and intensive staining of CD11b microglia marker were observed in the internal capsule of the mutant brain, a region of white matter containing residual OLs. Activated astrocytes with high glial fibrillary acidic protein-immunoreactivity were also mainly observed in white matter. Finally, we performed in situ hybridization using C/EBP homologous protein (CHOP) antisense probes to detect ER stressed cells. CHOP mRNA was strongly expressed in residual OLs in the Tabby-jp mutant mice at postnatal stages. These data show that microglia and astrocytes exhibit dynamic glial activation in response to cell death of OLs during Tabby-jp pathogenesis, and that CHOP antisense probes may be a good marker for the detection of ER-stressed OLs in jp mutant mice.
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Affiliation(s)
- Masanao Ikeda
- Division of Neurobiology and Anatomy, Niigata University, Niigata, 951-8510, Japan
- Department of Otolaryngology Head and Neck Surgery, Niigata University, Niigata, 951-8510, Japan
| | - M Ibrahim Hossain
- Division of Neurobiology and Anatomy, Niigata University, Niigata, 951-8510, Japan
| | - Li Zhou
- Division of Neurobiology and Anatomy, Niigata University, Niigata, 951-8510, Japan
| | - Masao Horie
- Division of Neurobiology and Anatomy, Niigata University, Niigata, 951-8510, Japan
| | - Kazuhiro Ikenaka
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, 444-8787, Japan
| | - Arata Horii
- Department of Otolaryngology Head and Neck Surgery, Niigata University, Niigata, 951-8510, Japan
| | - Hirohide Takebayashi
- Division of Neurobiology and Anatomy, Niigata University, Niigata, 951-8510, Japan.
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204
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Xu MX, Yu R, Shao LF, Zhang YX, Ge CX, Liu XM, Wu WY, Li JM, Kong LD. Up-regulated fractalkine (FKN) and its receptor CX3CR1 are involved in fructose-induced neuroinflammation: Suppression by curcumin. Brain Behav Immun 2016; 58:69-81. [PMID: 26765996 DOI: 10.1016/j.bbi.2016.01.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 12/08/2015] [Accepted: 01/01/2016] [Indexed: 12/11/2022] Open
Abstract
Recent studies suggest that diet-induced fractalkine (FKN) stimulates neuroinflammation in animal models of obesity, yet how it occurs is unclear. This study investigated the role of FKN and it receptor, CX3CR1, in fructose-induced neuroinflammation, and examined curcumin's beneficial effect. Fructose feeding was found to induce hippocampal microglia activation with neuroinflammation through the activation of the Toll-like receptor 4 (TLR4)/nuclear transcription factor κB (NF-κB) signaling, resulting in the reduction of neurogenesis in the dentate gyrus (DG) of mice. Serum FKN levels, as well as hypothalamic FKN and CX3CR1 gene expression, were significantly increased in fructose-fed mice with hypothalamic microglia activation. Hippocampal gene expression of FKN and CX3CR1 was also up-regulated at 14d and normalized at 56d in mice fed with fructose, which were consistent with the change of GFAP. Furthermore, immunostaining showed that GFAP and FKN expression was increased in cornu amonis 1, but decreased in DG in fructose-fed mice. In vitro studies showed that GFAP and FKN expression was stimulated in astrocytes, and suppressed in mixed glial cells exposed to 48h-fructose, with the continual increase of pro-inflammatory cytokines. Thus, increased FKN and CX3CR1 may cause a cross-talk between activated glial cells and neurons, playing an important role in the development of neuroinflammation in fructose-fed mice. Curcumin protected against neuronal damage in hippocampal DG of fructose-fed mice by inhibiting microglia activation and suppressed FKN/CX3CR1 up-regulation in the neuronal network. These results suggest a new therapeutic approach to protect against neuronal damage associated with dietary obesity-associated neuroinflammation.
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Affiliation(s)
- Min-Xuan Xu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Rong Yu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Li-Fei Shao
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Yan-Xiu Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Chen-Xu Ge
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Xin-Meng Liu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Wen-Yuan Wu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Jian-Mei Li
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China.
| | - Ling-Dong Kong
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China.
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205
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Eßlinger M, Wachholz S, Manitz MP, Plümper J, Sommer R, Juckel G, Friebe A. Schizophrenia associated sensory gating deficits develop after adolescent microglia activation. Brain Behav Immun 2016; 58:99-106. [PMID: 27235930 DOI: 10.1016/j.bbi.2016.05.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 05/05/2016] [Accepted: 05/24/2016] [Indexed: 10/21/2022] Open
Abstract
Maternal infection during pregnancy is a well-established risk factor for schizophrenia in the adult offspring. Consistently, prenatal Poly(I:C) treatment in mice has been validated to model behavioral and neurodevelopmental abnormalities associated with schizophrenia. By using the Poly(I:C) BALB/c mouse model, we investigated the functional profile of microglia by flow cytometry in relation to progressive behavioral changes from adolescence to adulthood. Prenatal Poly(I:C) treatment induced the expected sensory gating deficits (pre-pulse inhibition (PPI) of the acoustic startle response) in 100day-old adult offspring, but only in female not in male descendants. No PPI-deficits were present in 30day-old adolescent mice. Sensory gating deficits in adult females were preceded by a strong M1-type microglia polarization pattern during puberty as determined by flow cytometric analysis of multiple pro- and anti-inflammatory surface markers. Microglia activation in females did not persist until adulthood and was absent in behaviorally unaffected male descendants. Further, the specific activation pattern of microglia was not mirrored by a similar activation of peripheral immune cells. We conclude that prenatal Poly(I:C) treatment induces post pubertal deficits in sensory gating which are specifically preceded by a pro-inflammatory activation pattern of microglia during puberty.
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Affiliation(s)
- Manuela Eßlinger
- Laboratory of Psychoneuroimmunology, Department of Psychiatry, Center of Clinical Research 1 (ZKF1 2/052), Universitätsstraße 150, Ruhr University Bochum, D-44801 Bochum, Germany; Department of Psychiatry, LWL University Hospital, Ruhr-University Bochum, Alexandrinenstr. 1, D-44791 Bochum, Germany.
| | - Simone Wachholz
- Laboratory of Psychoneuroimmunology, Department of Psychiatry, Center of Clinical Research 1 (ZKF1 2/052), Universitätsstraße 150, Ruhr University Bochum, D-44801 Bochum, Germany; Department of Psychiatry, LWL University Hospital, Ruhr-University Bochum, Alexandrinenstr. 1, D-44791 Bochum, Germany.
| | - Marie-Pierre Manitz
- Laboratory of Psychoneuroimmunology, Department of Psychiatry, Center of Clinical Research 1 (ZKF1 2/052), Universitätsstraße 150, Ruhr University Bochum, D-44801 Bochum, Germany; Department of Psychiatry, LWL University Hospital, Ruhr-University Bochum, Alexandrinenstr. 1, D-44791 Bochum, Germany.
| | - Jennifer Plümper
- Laboratory of Psychoneuroimmunology, Department of Psychiatry, Center of Clinical Research 1 (ZKF1 2/052), Universitätsstraße 150, Ruhr University Bochum, D-44801 Bochum, Germany; Department of Psychiatry, LWL University Hospital, Ruhr-University Bochum, Alexandrinenstr. 1, D-44791 Bochum, Germany.
| | - Rainer Sommer
- Laboratory of Psychoneuroimmunology, Department of Psychiatry, Center of Clinical Research 1 (ZKF1 2/052), Universitätsstraße 150, Ruhr University Bochum, D-44801 Bochum, Germany.
| | - Georg Juckel
- Laboratory of Psychoneuroimmunology, Department of Psychiatry, Center of Clinical Research 1 (ZKF1 2/052), Universitätsstraße 150, Ruhr University Bochum, D-44801 Bochum, Germany; Department of Psychiatry, LWL University Hospital, Ruhr-University Bochum, Alexandrinenstr. 1, D-44791 Bochum, Germany.
| | - Astrid Friebe
- Laboratory of Psychoneuroimmunology, Department of Psychiatry, Center of Clinical Research 1 (ZKF1 2/052), Universitätsstraße 150, Ruhr University Bochum, D-44801 Bochum, Germany; Department of Psychiatry, LWL University Hospital, Ruhr-University Bochum, Alexandrinenstr. 1, D-44791 Bochum, Germany.
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206
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Seo Y, Kim HS, Kang I, Choi SW, Shin TH, Shin JH, Lee BC, Lee JY, Kim JJ, Kook MG, Kang KS. Cathepsin S contributes to microglia-mediated olfactory dysfunction through the regulation of Cx3cl1-Cx3cr1 axis in a Niemann-Pick disease type C1 model. Glia 2016; 64:2291-2305. [PMID: 27687148 DOI: 10.1002/glia.23077] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 09/12/2016] [Accepted: 09/15/2016] [Indexed: 12/28/2022]
Abstract
Microglia can aggravate olfactory dysfunction by mediating neuronal death in the olfactory bulb (OB) of a murine model of Niemann-Pick disease type C1 (NPC1), a fatal neurodegenerative disorder accompanied by lipid trafficking defects. In this study, we focused on the crosstalk between neurons and microglia to elucidate the mechanisms underlying extensive microgliosis in the NPC1-affected brain. Microglia in the OB of NPC1 mice strongly expressed CX3C chemokine receptor 1 (Cx3cr1), a specific receptor for the neural chemokine C-X3-C motif ligand 1 (Cx3cl1). In addition, a high level of Cx3cl1 was detected in NPC1 mouse-derived CSF due to enhanced catalytic activity of Cathepsin S (Ctss), which is responsible for Cx3cl1 secretion. Notably, nasal delivery of Cx3cl1 neutralizing antibody or Ctss inhibitor could inhibit the Cx3cl1-Cx3cr1 interaction and support neuronal survival through the suppression of microglial activation, leading to an improvement in the olfactory function in NPC1 mice. Relevant in vitro experiments revealed that intracellular cholesterol accumulation could act as a strong inducer of abnormal Ctss activation and, in turn, stimulated the Cx3cl1-Cx3cr1 axis in microglia via p38 mitogen-activated protein kinase signaling. Our data address the significance of Cx3cl1-Cx3cr1 interaction in the development of microglial neurotoxicity and suggest that Ctss is a key upstream regulator. Therefore, this study contributes to a better understanding of the crosstalk between neurons and microglia in the development of the neurodegeneration and provides a new perspective for the management of olfactory deficits and other microglia-dependent neuropathies. GLIA 2016;64:2291-2305.
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Affiliation(s)
- Yoojin Seo
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea.,School of Medicine, Pusan National University, Busan, 49241, South Korea.,Biomedical Research Institute, Pusan National University Hospital, Busan, 49241, South Korea
| | - Hyung-Sik Kim
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea.,School of Medicine, Pusan National University, Busan, 49241, South Korea.,Biomedical Research Institute, Pusan National University Hospital, Busan, 49241, South Korea
| | - Insung Kang
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea.,Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea
| | - Soon Won Choi
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea.,Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea
| | - Tae-Hoon Shin
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea.,Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea
| | - Ji-Hee Shin
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea.,Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea
| | - Byung-Chul Lee
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea.,Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea
| | - Jin Young Lee
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea.,Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea
| | - Jae-Jun Kim
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea
| | - Myung Geun Kook
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea.,Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea
| | - Kyung-Sun Kang
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea. .,Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea.
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207
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Hou XX, Zhou WJ, Wang XQ, Li DJ. Fractalkine/CX3CR1 is involved in the pathogenesis of endometriosis by regulating endometrial stromal cell proliferation and invasion. Am J Reprod Immunol 2016; 76:318-25. [DOI: 10.1111/aji.12557] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 08/02/2016] [Indexed: 01/21/2023] Open
Affiliation(s)
- Xin-Xin Hou
- Laboratory for Reproductive Immunology; Key Laboratory of Reproduction Regulation of NPFPC, SIPPR; Fudan University Shanghai Medical College; Shanghai China
- Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases; Hospital and Institute of Obstetrics and Gynecology, IRD; Fudan University Shanghai Medical College; Shanghai China
| | - Wen-Jie Zhou
- Laboratory for Reproductive Immunology; Key Laboratory of Reproduction Regulation of NPFPC, SIPPR; Fudan University Shanghai Medical College; Shanghai China
- Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases; Hospital and Institute of Obstetrics and Gynecology, IRD; Fudan University Shanghai Medical College; Shanghai China
| | - Xiao-Qiu Wang
- Laboratory for Reproductive Immunology; Key Laboratory of Reproduction Regulation of NPFPC, SIPPR; Fudan University Shanghai Medical College; Shanghai China
- Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases; Hospital and Institute of Obstetrics and Gynecology, IRD; Fudan University Shanghai Medical College; Shanghai China
| | - Da-Jin Li
- Laboratory for Reproductive Immunology; Key Laboratory of Reproduction Regulation of NPFPC, SIPPR; Fudan University Shanghai Medical College; Shanghai China
- Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases; Hospital and Institute of Obstetrics and Gynecology, IRD; Fudan University Shanghai Medical College; Shanghai China
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208
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O'Sullivan SA, Gasparini F, Mir AK, Dev KK. Fractalkine shedding is mediated by p38 and the ADAM10 protease under pro-inflammatory conditions in human astrocytes. J Neuroinflammation 2016; 13:189. [PMID: 27549131 PMCID: PMC4994207 DOI: 10.1186/s12974-016-0659-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Accepted: 07/13/2016] [Indexed: 01/01/2023] Open
Abstract
Background The fractalkine (CX3CR1) ligand is expressed in astrocytes and reported to be neuroprotective. When cleaved from the membrane, soluble fractalkine (sCX3CL1) activates the receptor CX3CR1. Although somewhat controversial, CX3CR1 is reported to be expressed in neurons and microglia. The membrane-bound form of CX3CL1 additionally acts as an adhesion molecule for microglia and infiltrating white blood cells. Much research has been done on the role of fractalkine in neuronal cells; however, little is known about the regulation of the CX3CL1 ligand in astrocytes. Methods The mechanisms involved in the up-regulation and cleavage of CX3CL1 from human astrocytes were investigated using immunocytochemistry, Q-PCR and ELISA. All statistical analysis was performed using GraphPad Prism 5. Results A combination of ADAM17 (TACE) and ADAM10 protease inhibitors was found to attenuate IL-1β-, TNF-α- and IFN-γ-induced sCX3CL1 levels in astrocytes. A specific ADAM10 (but not ADAM17) inhibitor also attenuated these effects, suggesting ADAM10 proteases induce release of sCX3CL1 from stimulated human astrocytes. A p38 MAPK inhibitor also attenuated the levels of sCX3CL1 upon treatment with IL-1β, TNF-α or IFN-γ. In addition, an IKKβ inhibitor significantly reduced the levels of sCX3CL1 induced by IL-1β or TNF-α in a concentration-dependent manner, suggesting a role for the NF-kB pathway. Conclusions In conclusion, this study shows that the release of soluble astrocytic fractalkine is regulated by ADAM10 proteases with p38 MAPK also playing a role in the fractalkine shedding event. These findings are important for understanding the role of CX3CL1 in healthy and stimulated astrocytes and may benefit our understanding of this pathway in neuro-inflammatory and neurodegenerative diseases. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0659-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sinead A O'Sullivan
- Drug Development, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Fabrizio Gasparini
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Anis K Mir
- Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Kumlesh K Dev
- Drug Development, School of Medicine, Trinity College Dublin, Dublin, Ireland.
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209
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Actions of Thyroid Hormone Analogues on Chemokines. J Immunol Res 2016; 2016:3147671. [PMID: 27493972 PMCID: PMC4967430 DOI: 10.1155/2016/3147671] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 06/15/2016] [Indexed: 12/27/2022] Open
Abstract
The extracellular domain of plasma membrane integrin αvβ3 contains a receptor for thyroid hormone (L-thyroxine, T4; 3,5,3′-triiodo-L-thyronine, T3); this receptor also binds tetraiodothyroacetic acid (tetrac), a derivative of T4. Tetrac inhibits the binding of T4 and T3 to the integrin. Fractalkine (CX3CL1) is a chemokine relevant to inflammatory processes in the CNS that are microglia-dependent but also important to normal brain development. Expression of the CX3CL1 gene is downregulated by tetrac, suggesting that T4 and T3 may stimulate fractalkine expression. Independently of its specific receptor (CX3CR1), fractalkine binds to αvβ3 at a site proximal to the thyroid hormone-tetrac receptor and changes the physical state of the integrin. Tetrac also affects expression of the genes for other CNS-relevant chemokines, including CCL20, CCL26, CXCL2, CXCL3, and CXCL10. The chemokine products of these genes are important to vascularity of the brain, particularly of the choroid plexus, to inflammatory processes in the CNS and, in certain cases, to neuroprotection. Thyroid hormones are known to contribute to regulation of each of these CNS functions. We propose that actions of thyroid hormone and hormone analogues on chemokine gene expression contribute to regulation of inflammatory processes in brain and of brain blood vessel formation and maintenance.
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210
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Milior G, Lecours C, Samson L, Bisht K, Poggini S, Pagani F, Deflorio C, Lauro C, Alboni S, Limatola C, Branchi I, Tremblay ME, Maggi L. Fractalkine receptor deficiency impairs microglial and neuronal responsiveness to chronic stress. Brain Behav Immun 2016; 55:114-125. [PMID: 26231972 DOI: 10.1016/j.bbi.2015.07.024] [Citation(s) in RCA: 166] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 07/25/2015] [Accepted: 07/26/2015] [Indexed: 12/25/2022] Open
Abstract
Chronic stress is one of the most relevant triggering factors for major depression. Microglial cells are highly sensitive to stress and, more generally, to environmental challenges. However, the role of these brain immune cells in mediating the effects of stress is still unclear. Fractalkine signaling - which comprises the chemokine CX3CL1, mainly expressed by neurons, and its receptor CX3CR1, almost exclusively present on microglia in the healthy brain - has been reported to critically regulate microglial activity. Here, we investigated whether interfering with microglial function by deleting the Cx3cr1 gene affects the brain's response to chronic stress. To this purpose, we housed Cx3cr1 knockout and wild-type adult mice in either control or stressful environments for 2weeks, and investigated the consequences on microglial phenotype and interactions with synapses, synaptic transmission, behavioral response and corticosterone levels. Our results show that hampering neuron-microglia communication via the CX3CR1-CX3CL1 pathway prevents the effects of chronic unpredictable stress on microglial function, short- and long-term neuronal plasticity and depressive-like behavior. Overall, the present findings suggest that microglia-regulated mechanisms may underlie the differential susceptibility to stress and consequently the vulnerability to diseases triggered by the experience of stressful events, such as major depression.
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Affiliation(s)
- Giampaolo Milior
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Italy
| | - Cynthia Lecours
- Axe Neurosciences, Centre de recherche du CHU de Québec, 2705, boulevard Laurier, Québec, Canada
| | - Louis Samson
- Axe Neurosciences, Centre de recherche du CHU de Québec, 2705, boulevard Laurier, Québec, Canada
| | - Kanchan Bisht
- Axe Neurosciences, Centre de recherche du CHU de Québec, 2705, boulevard Laurier, Québec, Canada
| | - Silvia Poggini
- Section of Behavioural Neurosciences, Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Rome, Italy
| | - Francesca Pagani
- Center for Life Nanoscience, Istituto Italiano di Tecnologia@Sapienza, Rome, Italy
| | - Cristina Deflorio
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Italy; Département de Neuroscience, Institut Pasteur, Unité Neurobiologie Intégrative des Systèmes Cholinergiques, Paris Cedex 15, Paris, France
| | - Clotilde Lauro
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Italy
| | - Silvia Alboni
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Cristina Limatola
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Italy; IRCCS Neuromed, Pozzilli, IS, Italy
| | - Igor Branchi
- Section of Behavioural Neurosciences, Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Rome, Italy
| | - Marie-Eve Tremblay
- Axe Neurosciences, Centre de recherche du CHU de Québec, 2705, boulevard Laurier, Québec, Canada.
| | - Laura Maggi
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Italy
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Ahl M, Avdic U, Skoug C, Ali I, Chugh D, Johansson UE, Ekdahl CT. Immune response in the eye following epileptic seizures. J Neuroinflammation 2016; 13:155. [PMID: 27346214 PMCID: PMC4922060 DOI: 10.1186/s12974-016-0618-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 06/08/2016] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Epileptic seizures are associated with an immune response in the brain. However, it is not known whether it can extend to remote areas of the brain, such as the eyes. Hence, we investigated whether epileptic seizures induce inflammation in the retina. METHODS Adult rats underwent electrically induced temporal status epilepticus, and the eyes were studied 6 h, 1, and 7 weeks later with biochemical and immunohistochemical analyses. An additional group of animals received CX3CR1 antibody intracerebroventricularly for 6 weeks after status epilepticus. RESULTS Biochemical analyses and immunohistochemistry revealed no increased cell death and unaltered expression of several immune-related cytokines and chemokines as well as no microglial activation, 6 h post-status epilepticus compared to non-stimulated controls. At 1 week, again, retinal cytoarchitecture appeared normal and there was no cell death or micro- or macroglial reaction, apart from a small decrease in interleukin-10. However, at 7 weeks, even if the cytoarchitecture remained normal and no ongoing cell death was detected, the numbers of microglia were increased ipsi- and contralateral to the epileptic focus. The microglia remained within the synaptic layers but often in clusters and with more processes extending into the outer nuclear layer. Morphological analyses revealed a decrease in surveying and an increase in activated microglia. In addition, increased levels of the chemokine KC/GRO and cytokine interleukin-1β were found. Furthermore, macroglial activation was noted in the inner retina. No alterations in numbers of phagocytic cells, infiltrating macrophages, or vascular pericytes were observed. Post-synaptic density-95 cluster intensity was reduced in the outer nuclear layer, reflecting seizure-induced synaptic changes without disrupted cytoarchitecture in areas with increased microglial activation. The retinal gliosis was decreased by a CX3CR1 immune modulation known to reduce gliosis within epileptic foci, suggesting a common immunological reaction. CONCLUSIONS Our results are the first evidence that epileptic seizures induce an immune response in the retina. It has a potential to become a novel non-invasive tool for detecting brain inflammation through the eyes.
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Affiliation(s)
- Matilda Ahl
- Inflammation and Stem Cell Therapy Group, Division of Clinical Neurophysiology, Lund University, BMC A11, Sölvegatan 17, SE-221 84, Lund, Sweden.,Lund Epilepsy Center, Lund University, SE-221 85, Lund, Sweden
| | - Una Avdic
- Inflammation and Stem Cell Therapy Group, Division of Clinical Neurophysiology, Lund University, BMC A11, Sölvegatan 17, SE-221 84, Lund, Sweden.,Lund Epilepsy Center, Lund University, SE-221 85, Lund, Sweden
| | - Cecilia Skoug
- Division of Ophthalmology, Department of Clinical Sciences, Lund University, SE-221 85, Lund, Sweden
| | - Idrish Ali
- Inflammation and Stem Cell Therapy Group, Division of Clinical Neurophysiology, Lund University, BMC A11, Sölvegatan 17, SE-221 84, Lund, Sweden.,Lund Epilepsy Center, Lund University, SE-221 85, Lund, Sweden
| | - Deepti Chugh
- Inflammation and Stem Cell Therapy Group, Division of Clinical Neurophysiology, Lund University, BMC A11, Sölvegatan 17, SE-221 84, Lund, Sweden.,Lund Epilepsy Center, Lund University, SE-221 85, Lund, Sweden
| | - Ulrica Englund Johansson
- Division of Ophthalmology, Department of Clinical Sciences, Lund University, SE-221 85, Lund, Sweden
| | - Christine T Ekdahl
- Inflammation and Stem Cell Therapy Group, Division of Clinical Neurophysiology, Lund University, BMC A11, Sölvegatan 17, SE-221 84, Lund, Sweden. .,Lund Epilepsy Center, Lund University, SE-221 85, Lund, Sweden.
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212
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Bégin-Lavallée V, Midavaine É, Dansereau MA, Tétreault P, Longpré JM, Jacobi AM, Rose SD, Behlke MA, Beaudet N, Sarret P. Functional inhibition of chemokine receptor CCR2 by dicer-substrate-siRNA prevents pain development. Mol Pain 2016; 12:12/0/1744806916653969. [PMID: 27306408 PMCID: PMC4956154 DOI: 10.1177/1744806916653969] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 05/16/2016] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Accumulating evidence suggests that the C-C chemokine ligand 2 (CCL2, or monocyte chemoattractant protein 1) acts as a neuromodulator in the central nervous system through its binding to the C-C chemokine receptor 2 (CCR2). Notably, it is well established that the CCL2/CCR2 axis plays a key role in neuron-glia communication as well as in spinal nociceptive transmission. Gene silencing through RNA interference has recently emerged as a promising avenue in research and drug development, including therapeutic management of chronic pain. In the present study, we used 27-mer Dicer-substrate small interfering RNA (DsiRNA) targeting CCR2 and assessed their ability to reverse the nociceptive behaviors induced by spinal CCL2 injection or following intraplantar injection of complete Freund's adjuvant. RESULTS To this end, we first developed high-potency DsiRNAs designed to target different sequences distributed across the rat CCR2 (rCCR2) messenger RNA. For optimization, methyl groups were added to the two most potent DsiRNA candidates (Evader and M7 2'-O-methyl modified duplexes) in order to improve in vivo duplex stability and to reduce potential immunostimulatory activity. Our results demonstrated that all modified candidates formulated with the cell-penetrating peptide reagent Transductin showed strong RNAi activity following intrathecal delivery, exhibiting >50% rCCR2 knockdown in lumbar dorsal root ganglia. Accordingly, we found that these DsiRNA duplexes were able to reduce spinal microglia activation and were effective at blocking CCL2-induced mechanical hypersensitivity. Along with similar reductions of rCCR2 messenger RNA, both sequences and methylation patterns were similarly effective in inhibiting the CCL2 nociceptive action for the whole seven days testing period, compared to mismatch DsiRNA. DsiRNAs against CCR2 also reversed the hypernociceptive responses observed in the complete Freund's adjuvant-induced inflammatory chronic pain model. CONCLUSION Altogether, these results validate CCR2 as a an appropriate molecular target for pain control and demonstrate that RNAi-based gene therapy represent an highly specific alternative to classical pharmacological approaches to treat central pathologies such as chronic pain.
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Affiliation(s)
- Valérie Bégin-Lavallée
- Department of Pharmacology and Physiology, Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
- Philippe Sarret, Department of Pharmacology and Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke, QC, Canada.
| | - Élora Midavaine
- Department of Pharmacology and Physiology, Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Marc-André Dansereau
- Department of Pharmacology and Physiology, Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Pascal Tétreault
- Department of Pharmacology and Physiology, Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Jean-Michel Longpré
- Department of Pharmacology and Physiology, Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | | | - Scott D Rose
- Integrated DNA Technologies Inc, Coralville, IA, USA
| | - Mark A Behlke
- Integrated DNA Technologies Inc, Coralville, IA, USA
| | - Nicolas Beaudet
- Department of Anesthesiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Philippe Sarret
- Department of Pharmacology and Physiology, Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
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213
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Cairns BE, O'Brien M, Dong XD, Gazerani P. Elevated Fractalkine (CX3CL1) Levels in the Trigeminal Ganglion Mechanically Sensitize Temporalis Muscle Nociceptors. Mol Neurobiol 2016; 54:3695-3706. [PMID: 27209190 DOI: 10.1007/s12035-016-9935-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 05/10/2016] [Indexed: 12/11/2022]
Abstract
It has been proposed that after nerve injury or tissue inflammation, fractalkine (CX3CL1) released from dorsal root ganglion neurons acts on satellite glial cells (SGCs) through CX3C receptor 1 (CX3CR1) to induce neuroplastic changes. The existence and importance of fractalkine/CX3CR1 signaling in the trigeminal ganglia has not yet been clarified. This study investigated (1) whether trigeminal ganglion neurons that innervate temporalis muscle and their associated SGCs contain fractalkine and/or express CX3CR1, (2) if intraganglionic injection of fractalkine increases the mechanical sensitivity of temporalis muscle afferent fibers, (3) whether complete Freund's adjuvant (CFA)-induced inflammation of the temporalis muscle alters the expression of fractalkine or its receptor in the trigeminal ganglion, and (4) if intraganglionic administration of CX3CR1 antibodies alters afferent mechanical sensitivity. Immunohistochemistry and in vivo electrophysiological recordings in male and female rats were used to address these questions. It was found that ∼50 % of temporalis ganglion neurons and ∼25 % of their associated SGCs express CX3CR1, while only neurons expressed fractalkine. Temporalis muscle inflammation increased the expression of fractalkine, but only in male rats. Intraganglionic injection of fractalkine (25 g/ml; 3 μl) induced prolonged afferent mechanical sensitization. Intraganglionic injection of CX3CR1 antibody increased afferent mechanical threshold, but this effect was greater in controls than in rats with CFA-induced muscle inflammation. These findings raise the possibility that basal fractalkine signalling within the trigeminal ganglion plays an important role in mechanical sensitivity of masticatory muscle sensory afferent fibers and that inhibition of CX3CR1 signaling within the trigeminal ganglia may induce analgesia through a peripheral mechanism.
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Affiliation(s)
- Brian E Cairns
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, Canada.,SMI®, Department of Health Science and Technology, The Faculty of Medicine, Aalborg University, Fredrik Bajers Vej 7-D3, 9220, Aalborg East, Denmark
| | - Melissa O'Brien
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, Canada
| | - Xu-Dong Dong
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, Canada
| | - Parisa Gazerani
- SMI®, Department of Health Science and Technology, The Faculty of Medicine, Aalborg University, Fredrik Bajers Vej 7-D3, 9220, Aalborg East, Denmark.
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214
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Ślusarczyk J, Trojan E, Wydra K, Głombik K, Chamera K, Kucharczyk M, Budziszewska B, Kubera M, Lasoń W, Filip M, Basta-Kaim A. Beneficial impact of intracerebroventricular fractalkine administration on behavioral and biochemical changes induced by prenatal stress in adult rats: Possible role of NLRP3 inflammasome pathway. Biochem Pharmacol 2016; 113:45-56. [PMID: 27206338 DOI: 10.1016/j.bcp.2016.05.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 05/16/2016] [Indexed: 12/30/2022]
Abstract
Several lines of evidence indicate that adverse experience in early life may be a triggering factor for pathological inflammatory processes and lead to the development of depression. Fractalkine (CX3CL1), a chemokine, plays an important role not only in the migration, differentiation and proliferation of neuronal and glial cells but also in the regulation of neuronal-microglial signaling and the production of pro-inflammatory factors. In the present study, we examined the impact of a prenatal stress procedure on the expression of fractalkine in the hippocampus and frontal cortex of young and adult male rats. Furthermore, we measured the age-dependent effect of stress during pregnancy on the expression of pro-inflammatory factors IL-1β, IL-18, TNF-α, IL-6, and CCL2 in both brain structures. Next, to illustrate the link between fractalkine signaling and the behavioral and biochemical changes induced by prenatal stress, adult prenatally stressed offspring were injected intracerebroventricularly (icv) with exogenous fractalkine. We reported that prenatal stress leads to long-lasting deficits in fractalkine signaling and enhanced inflammatory activation. The study demonstrates that icv administration of fractalkine attenuates the behavioural changes evoked by prenatal stress procedure in adult animals. Moreover, fractalkine administration, exhibits anti-inflammatory action, mainly in the frontal cortex of adult prenatally stressed rats. The effect of fractalkine is related to inhibition of NLRP3 inflammasome. However, its action on the other members of NOD-like receptor family (NLR) cannot be excluded. These findings provide new in vivo evidence that the behavioral and inflammatory disturbances observed in adult prenatally stressed rats may be related to long-lasting malfunctions in fractalkine signaling.
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Affiliation(s)
- Joanna Ślusarczyk
- Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Krakow, Poland
| | - Ewa Trojan
- Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Krakow, Poland
| | - Karolina Wydra
- Laboratory of Drug Addiction, Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Krakow, Poland
| | - Katarzyna Głombik
- Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Krakow, Poland
| | - Katarzyna Chamera
- Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Krakow, Poland
| | - Mateusz Kucharczyk
- Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Krakow, Poland
| | - Bogusława Budziszewska
- Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Krakow, Poland
| | - Marta Kubera
- Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Krakow, Poland
| | - Władysław Lasoń
- Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Krakow, Poland
| | - Małgorzata Filip
- Laboratory of Drug Addiction, Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Krakow, Poland
| | - Agnieszka Basta-Kaim
- Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Krakow, Poland.
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215
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Aspirin Action in Endothelial Cells: Different Patterns of Response Between Chemokine CX3CL1/CX3CR1 and TNF-α/TNFR1 Signaling Pathways. Cardiovasc Drugs Ther 2016; 29:219-29. [PMID: 25959742 PMCID: PMC4522030 DOI: 10.1007/s10557-015-6589-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Purpose TNF-α induces fractalkine (CX3CL1) and its receptor CX3CR1 in endothelial cells through NF-қB activation. NF-қB inhibitors may reduce the expression of CX3CL1, and modulation of the CX3CL1/CX3CR1 signaling was proposed as a new target for aspirin. We examined the effects of aspirin on CX3CL1 and TNF-α production, as well as CX3CR1 and TNFR1 expression. Methods HUVECs isolated after term pregnancies (N = 28) were cultured in vitro. Lipopolysaccharide (1 μg/ml) was used as CX3CL1 inducer. HUVECs were exposed to six different concentrations of aspirin (between 1.0 and 6.0 mM) during 7 days. The levels of CX3CL1 and TNF-α in the culture media were measured using ELISA. After termination of the cultures, mean expressions of CX3CR1 and TNFR1 were examined in the immunostained paraffin sections using quantitative immunohistochemistry. Results Aspirin significantly (p < 0.05) decreased CX3CL1 production, and the mean decrease in CX3CL1 production was inversely proportional to increased (p < 0.05) expression of CX3CR1. The combined mean CX3CL1 concentrations, including all time points, equaled 782.18 ± 74.4 pg/ml in aspirin treated HUVECs compared to a total concentration of 2467.53 ± 127.5 pg/ml combined from the respective time points in the controls. An inhibition of TNF-α production in HUVECs after pretreatment with aspirin was observed. Unlike in the case of CX3CR1 expression, there were no signs of TNFR1 upregulation. Conclusions Autoregulation between CX3CL1 and CX3CR1 may explain overexpression of CX3CR1 as the compensatory effect in aspirin-treated HUVECs. Inhibition of CX3CR1 could prevent thrombotic complications in the early period after discontinuation of aspirin.
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216
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Meireles M, Marques C, Norberto S, Santos P, Fernandes I, Mateus N, Faria A, Calhau C. Anthocyanin effects on microglia M1/M2 phenotype: Consequence on neuronal fractalkine expression. Behav Brain Res 2016; 305:223-8. [DOI: 10.1016/j.bbr.2016.03.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 02/29/2016] [Accepted: 03/05/2016] [Indexed: 02/03/2023]
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217
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Xing C, Lo EH. Help-me signaling: Non-cell autonomous mechanisms of neuroprotection and neurorecovery. Prog Neurobiol 2016; 152:181-199. [PMID: 27079786 DOI: 10.1016/j.pneurobio.2016.04.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 04/06/2016] [Accepted: 04/09/2016] [Indexed: 12/11/2022]
Abstract
Self-preservation is required for life. At the cellular level, this fundamental principle is expressed in the form of molecular mechanisms for preconditioning and tolerance. When the cell is threatened, internal cascades of survival signaling become triggered to protect against cell death and defend against future insults. Recently, however, emerging findings suggest that this principle of self-preservation may involve not only intracellular signals; the release of extracellular signals may provide a way to recruit adjacent cells into an amplified protective program. In the central nervous system where multiple cell types co-exist, this mechanism would allow threatened neurons to "ask for help" from glial and vascular compartments. In this review, we describe this new concept of help-me signaling, wherein damaged or diseased neurons release signals that may shift glial and vascular cells into potentially beneficial phenotypes, and help remodel the neurovascular unit. Understanding and dissecting these non-cell autonomous mechanisms of self-preservation in the CNS may lead to novel opportunities for neuroprotection and neurorecovery.
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Affiliation(s)
- Changhong Xing
- Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA.
| | - Eng H Lo
- Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA.
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218
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Silverman SM, Kim BJ, Howell GR, Miller J, John SWM, Wordinger RJ, Clark AF. C1q propagates microglial activation and neurodegeneration in the visual axis following retinal ischemia/reperfusion injury. Mol Neurodegener 2016; 11:24. [PMID: 27008854 PMCID: PMC4806521 DOI: 10.1186/s13024-016-0089-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 03/18/2016] [Indexed: 12/03/2022] Open
Abstract
Background C1q represents the initiating protein of the classical complement cascade, however recent findings indicate pathway independent roles such as developmental pruning of retinal ganglion cell (RGC) axons. Furthermore, chronic neuroinflammation, including increased expression of C1q and activation of microglia and astrocytes, appears to be a common finding among many neurodegenerative disease models. Here we compare the effects of a retinal ischemia/reperfusion (I/R) injury on glial activation and neurodegeneration in wild type (WT) and C1qa-deficient mice in the retina and superior colliculus (SC). Retinal I/R was induced in mice through elevation of intraocular pressure to 120 mmHg for 60 min followed by reperfusion. Glial cell activation and population changes were assessed using immunofluorescence. Neuroprotection was determined using histological measurements of retinal layer thickness, RGC counts, and visual function by flash electroretinography (ERG). Results Retinal I/R injury significantly upregulated C1q expression in the retina as early as 72 h and within 7 days in the superficial SC, and was sustained as long as 28 days. Accompanying increased C1q expression was activation of microglia and astrocytes as well as a significantly increased glial population density observed in the retina and SC. Microglial activation and changes in density were completely ablated in C1qa-deficient mice, interestingly however there was no effect on astrocytes. Furthermore, loss of C1qa significantly rescued I/R-induced loss of RGCs and protected against retinal layer thinning in comparison to WT mice. ERG assessment revealed early preservation of b-wave amplitude deficits from retinal I/R injury due to C1qa-deficiency that was lost by day 28. Conclusions Our results for the first time demonstrate the spatiotemporal changes in the neuroinflammatory response following retinal I/R injury at both local and distal sites of injury. In addition, we have shown a role for C1q as a primary mediator of microglial activation and pathological damage. This suggests developmental mechanisms of C1q may be re-engaged during injury response, modulation of which may be beneficial for neuroprotection. Electronic supplementary material The online version of this article (doi:10.1186/s13024-016-0089-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sean M Silverman
- North Texas Eye Research Institute, University of North Texas Health Science Center, CBH-441, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA
| | - Byung-Jin Kim
- North Texas Eye Research Institute, University of North Texas Health Science Center, CBH-441, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA
| | | | | | - Simon W M John
- The Jackson Laboratory, Bar Harbor, 04609, ME, USA.,Howard Hughes Medical Institute, Bar Harbor, ME, 04609, USA
| | - Robert J Wordinger
- North Texas Eye Research Institute, University of North Texas Health Science Center, CBH-441, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA
| | - Abbot F Clark
- North Texas Eye Research Institute, University of North Texas Health Science Center, CBH-441, 3500 Camp Bowie Boulevard, Fort Worth, TX, 76107, USA.
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219
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Poniatowski ŁA, Wojdasiewicz P, Krawczyk M, Szukiewicz D, Gasik R, Kubaszewski Ł, Kurkowska-Jastrzębska I. Analysis of the Role of CX3CL1 (Fractalkine) and Its Receptor CX3CR1 in Traumatic Brain and Spinal Cord Injury: Insight into Recent Advances in Actions of Neurochemokine Agents. Mol Neurobiol 2016; 54:2167-2188. [PMID: 26927660 PMCID: PMC5355526 DOI: 10.1007/s12035-016-9787-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 02/11/2016] [Indexed: 12/23/2022]
Abstract
CX3CL1 (fractalkine) is the only member of the CX3C (delta) subfamily of chemokines which is unique and combines the properties of both chemoattractant and adhesion molecules. The two-form ligand can exist either in a soluble form, like all other chemokines, and as a membrane-anchored molecule. CX3CL1 discloses its biological properties through interaction with one dedicated CX3CR1 receptor which belongs to a family of G protein-coupled receptors (GPCR). The CX3CL1/CX3CR1 axis acts in many physiological phenomena including those occurring in the central nervous system (CNS), by regulating the interactions between neurons, microglia, and immune cells. Apart from the role under physiological conditions, the CX3CL1/CX3CR1 axis was implied to have a role in different neuropathologies such as traumatic brain injury (TBI) and spinal cord injury (SCI). CNS injuries represent a serious public health problem, despite improvements in therapeutic management. To date, no effective treatment has been determined, so they constitute a leading cause of death and severe disability. The course of TBI and SCI has two consecutive poorly demarcated phases: the initial, primary injury and secondary injury. Recent evidence has implicated the role of the CX3CL1/CX3CR1 axis in neuroinflammatory processes occurring after CNS injuries. The importance of the CX3CL1/CX3CR1 axis in the pathophysiology of TBI and SCI in the context of systemic and direct local immune response is still under investigation. This paper, based on a review of the literature, updates and summarizes the current knowledge about CX3CL1/CX3CR1 axis involvement in TBI and SCI pathogenesis, indicating possible molecular and cellular mechanisms with a potential target for therapeutic intervention.
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Affiliation(s)
- Łukasz A Poniatowski
- Department of General and Experimental Pathology, 2nd Faculty of Medicine, Medical University of Warsaw, Pawińskiego 3C, 02-106, Warsaw, Poland.
| | - Piotr Wojdasiewicz
- Department of General and Experimental Pathology, 2nd Faculty of Medicine, Medical University of Warsaw, Pawińskiego 3C, 02-106, Warsaw, Poland.,Department of Rheumaorthopaedics, Eleonora Reicher National Institute of Geriatrics, Rheumatology and Rehabilitation, Spartańska 1, 02-637, Warsaw, Poland.,Department of Neuroorthopaedics and Neurology, Eleonora Reicher National Institute of Geriatrics, Rheumatology and Rehabilitation, Spartańska 1, 02-637, Warsaw, Poland
| | - Maciej Krawczyk
- 2nd Department of Neurology, Institute of Psychiatry and Neurology, Sobieskiego 9, 02-957, Warsaw, Poland.,Department of Pediatric and Neurological Rehabilitation, Faculty of Rehabilitation, Józef Piłsudski University of Physical Education, Marymoncka 34, 00-968, Warsaw, Poland
| | - Dariusz Szukiewicz
- Department of General and Experimental Pathology, 2nd Faculty of Medicine, Medical University of Warsaw, Pawińskiego 3C, 02-106, Warsaw, Poland
| | - Robert Gasik
- Department of Rheumaorthopaedics, Eleonora Reicher National Institute of Geriatrics, Rheumatology and Rehabilitation, Spartańska 1, 02-637, Warsaw, Poland.,Department of Neuroorthopaedics and Neurology, Eleonora Reicher National Institute of Geriatrics, Rheumatology and Rehabilitation, Spartańska 1, 02-637, Warsaw, Poland
| | - Łukasz Kubaszewski
- Department of Neuroorthopaedics and Neurology, Eleonora Reicher National Institute of Geriatrics, Rheumatology and Rehabilitation, Spartańska 1, 02-637, Warsaw, Poland.,Department of Orthopaedics and Traumatology, Wiktor Dega Orthopaedic and Rehabilitation Clinical Hospital, Poznań University of Medical Sciences, 28 Czerwca 1956 135/147, 61-545, Poznań, Poland
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Kaplan BLF, Li J, LaPres JJ, Pruett SB, Karmaus PWF. Contributions of nonhematopoietic cells and mediators to immune responses: implications for immunotoxicology. Toxicol Sci 2016; 145:214-32. [PMID: 26008184 DOI: 10.1093/toxsci/kfv060] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Immunotoxicology assessments have historically focused on the effects that xenobiotics exhibit directly on immune cells. These studies are invaluable as they identify immune cell targets and help characterize mechanisms and/or adverse outcome pathways of xenobiotics within the immune system. However, leukocytes can receive environmental cues by cell-cell contact or via released mediators from cells of organs outside of the immune system. These organs include, but are not limited to, the mucosal areas such as the lung and the gut, the liver, and the central nervous system. Homeostatic perturbation in these organs induced directly by toxicants can initiate and alter the outcome of local and systemic immunity. This review will highlight some of the identified nonimmune influences on immune homeostasis and provide summaries of how immunotoxic mechanisms of selected xenobiotics involve nonimmune cells or mediators. Thus, this review will identify data gaps and provide possible alternative mechanisms by which xenobiotics alter immune function that could be considered during immunotoxicology safety assessment.
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Affiliation(s)
- Barbara L F Kaplan
- *Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi St, Mississippi 39762, Safety Assessment, Genentech, Inc. South San Francisco, California 94080, Department of Biochemistry and Molecular Biology, Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824 and Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Jinze Li
- *Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi St, Mississippi 39762, Safety Assessment, Genentech, Inc. South San Francisco, California 94080, Department of Biochemistry and Molecular Biology, Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824 and Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - John J LaPres
- *Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi St, Mississippi 39762, Safety Assessment, Genentech, Inc. South San Francisco, California 94080, Department of Biochemistry and Molecular Biology, Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824 and Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Stephen B Pruett
- *Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi St, Mississippi 39762, Safety Assessment, Genentech, Inc. South San Francisco, California 94080, Department of Biochemistry and Molecular Biology, Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824 and Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Peer W F Karmaus
- *Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi St, Mississippi 39762, Safety Assessment, Genentech, Inc. South San Francisco, California 94080, Department of Biochemistry and Molecular Biology, Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824 and Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
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Rustenhoven J, Aalderink M, Scotter EL, Oldfield RL, Bergin PS, Mee EW, Graham ES, Faull RLM, Curtis MA, Park TIH, Dragunow M. TGF-beta1 regulates human brain pericyte inflammatory processes involved in neurovasculature function. J Neuroinflammation 2016; 13:37. [PMID: 26867675 PMCID: PMC4751726 DOI: 10.1186/s12974-016-0503-0] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/03/2016] [Indexed: 12/17/2022] Open
Abstract
Background Transforming growth factor beta 1 (TGFβ1) is strongly induced following brain injury and polarises microglia to an anti-inflammatory phenotype. Augmentation of TGFβ1 responses may therefore be beneficial in preventing inflammation in neurological disorders including stroke and neurodegenerative diseases. However, several other cell types display immunogenic potential and identifying the effect of TGFβ1 on these cells is required to more fully understand its effects on brain inflammation. Pericytes are multifunctional cells which ensheath the brain vasculature and have garnered recent attention with respect to their immunomodulatory potential. Here, we sought to investigate the inflammatory phenotype adopted by TGFβ1-stimulated human brain pericytes. Methods Microarray analysis was performed to examine transcriptome-wide changes in TGFβ1-stimulated pericytes, and results were validated by qRT-PCR and cytometric bead arrays. Flow cytometry, immunocytochemistry and LDH/Alamar Blue® viability assays were utilised to examine phagocytic capacity of human brain pericytes, transcription factor modulation and pericyte health. Results TGFβ1 treatment of primary human brain pericytes induced the expression of several inflammatory-related genes (NOX4, COX2, IL6 and MMP2) and attenuated others (IL8, CX3CL1, MCP1 and VCAM1). A synergistic induction of IL-6 was seen with IL-1β/TGFβ1 treatment whilst TGFβ1 attenuated the IL-1β-induced expression of CX3CL1, MCP-1 and sVCAM-1. TGFβ1 was found to signal through SMAD2/3 transcription factors but did not modify nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) translocation. Furthermore, TGFβ1 attenuated the phagocytic ability of pericytes, possibly through downregulation of the scavenger receptors CD36, CD47 and CD68. Whilst TGFβ did decrease pericyte number, this was due to a reduction in proliferation, not apoptotic death or compromised cell viability. Conclusions TGFβ1 attenuated pericyte expression of key chemokines and adhesion molecules involved in CNS leukocyte trafficking and the modulation of microglial function, as well as reduced the phagocytic ability of pericytes. However, TGFβ1 also enhanced the expression of classical pro-inflammatory cytokines and enzymes which can disrupt BBB functioning, suggesting that pericytes adopt a phenotype which is neither solely pro- nor anti-inflammatory. Whilst the effects of pericyte modulation by TGFβ1 in vivo are difficult to infer, the reduction in pericyte proliferation together with the elevated IL-6, MMP-2 and NOX4 and reduced phagocytosis suggests a detrimental action of TGFβ1 on neurovasculature. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0503-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Justin Rustenhoven
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Auckland, 1023, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, 1023, New Zealand
| | - Miranda Aalderink
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Auckland, 1023, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, 1023, New Zealand
| | - Emma L Scotter
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Auckland, 1023, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, 1023, New Zealand
| | | | - Peter S Bergin
- Centre for Brain Research, The University of Auckland, Auckland, 1023, New Zealand.,Auckland City Hospital, Auckland, 1023, New Zealand
| | - Edward W Mee
- Centre for Brain Research, The University of Auckland, Auckland, 1023, New Zealand.,Auckland City Hospital, Auckland, 1023, New Zealand
| | - E Scott Graham
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Auckland, 1023, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, 1023, New Zealand
| | - Richard L M Faull
- Department of Anatomy, The University of Auckland, Auckland, 1023, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, 1023, New Zealand
| | - Maurice A Curtis
- Department of Anatomy, The University of Auckland, Auckland, 1023, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, 1023, New Zealand
| | - Thomas I-H Park
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Auckland, 1023, New Zealand.,Department of Anatomy, The University of Auckland, Auckland, 1023, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, 1023, New Zealand
| | - Mike Dragunow
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Auckland, 1023, New Zealand. .,Centre for Brain Research, The University of Auckland, Auckland, 1023, New Zealand.
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222
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Bollinger JL, Bergeon Burns CM, Wellman CL. Differential effects of stress on microglial cell activation in male and female medial prefrontal cortex. Brain Behav Immun 2016; 52:88-97. [PMID: 26441134 PMCID: PMC4909118 DOI: 10.1016/j.bbi.2015.10.003] [Citation(s) in RCA: 159] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 09/25/2015] [Accepted: 10/02/2015] [Indexed: 12/19/2022] Open
Abstract
Susceptibility to stress-linked psychological disorders, including post-traumatic stress disorder and depression, differs between men and women. Dysfunction of medial prefrontal cortex (mPFC) has been implicated in many of these disorders. Chronic stress affects mPFC in a sex-dependent manner, differentially remodeling dendritic morphology and disrupting prefrontally mediated behaviors in males and females. Chronic restraint stress induces microglial activation, reflected in altered microglial morphology and immune factor expression, in mPFC in male rats. Unstressed females exhibit increased microglial ramification in several brain regions compared to males, suggesting both heightened basal activation and a potential for sex-dependent effects of stress on microglial activation. Therefore, we assessed microglial density and ramification in the prelimbic region of mPFC, and immune-associated genes in dorsal mPFC in male and female rats following acute or chronic restraint stress. Control rats were left unstressed. On the final day of restraint, brains were collected for either qPCR or visualization of microglia using Iba-1 immunohistochemistry. Microglia in mPFC were classified as ramified, primed, reactive, or amoeboid, and counted stereologically. Expression of microglia-associated genes (MHCII, CD40, IL6, CX3CL1, and CX3CR1) was also assessed using qPCR. Unstressed females showed a greater proportion of primed to ramified microglia relative to males, alongside heightened CX3CL1-CX3CR1 expression. Acute and chronic restraint stress reduced the proportion of primed to ramified microglia and microglial CD40 expression in females, but did not significantly alter microglial activation in males. This sex difference in microglial activation could contribute to the differential effects of stress on mPFC structure and function in males versus females.
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Affiliation(s)
- Justin L Bollinger
- Department of Psychological and Brain Sciences, Program in Neuroscience, Indiana University, Bloomington, IN 47405, United States; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, United States
| | - Christine M Bergeon Burns
- Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, United States
| | - Cara L Wellman
- Department of Psychological and Brain Sciences, Program in Neuroscience, Indiana University, Bloomington, IN 47405, United States; Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, United States.
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Fractalkine Signaling Regulates the Inflammatory Response in an α-Synuclein Model of Parkinson Disease. PLoS One 2015; 10:e0140566. [PMID: 26469270 PMCID: PMC4607155 DOI: 10.1371/journal.pone.0140566] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/28/2015] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Parkinson disease (PD) is a progressive neurodegenerative disorder characterized by loss of dopamine neurons in the substantia nigra pars compacta (SNpc) and widespread aggregates of the protein alpha-synuclein (α-syn). Increasing evidence points to inflammation as a chief mediator; however, the role of α-syn in triggering and sustaining inflammation remains unclear. In models of Alzheimer's disease (AD), multiple sclerosis (MS) and neurotoxin models of PD, the chemokine CX3CL1 (fractalkine) and its receptor (CX3CR1) have important roles in modulating neuroinflammation. METHODS To examine the role of fractalkine signaling in α-syn-induced-neuroinflammation and neurodegeneration, we used an in vivo mouse model in which human α-syn is overexpressed by an adeno associated viral vector serotype 2 (AAV2) and in vitro phagocytosis and protein internalization assays with primary microglia treated with aggregated α-syn. RESULTS We observed that loss of CX3CR1 expression led to a reduced inflammatory response, with reduced IgG deposition and expression of MHCII 4 weeks post-transduction. Six months post transduction, AAV2 mediated overexpression of α-syn leads to loss of dopaminergic neurons, and this loss was not exacerbated in animals with deletion of CX3CR1. To determine the mechanism by which CX3CR1affects inflammatory responses in α-syn-induced inflammation, phagocytosis was assessed using a fluorescent microsphere assay as well as by microglial uptake of aggregated α-syn. CX3CR1-/- microglia showed reduced uptake of fluorescent beads and aggregated α-syn. CONCLUSION Our results suggest that one mechanism by which CX3CR1-/- attenuates inflammation is at the level of phagocytosis of aggregated α-syn by microglia. These data implicate fractalkine signaling as a potential therapeutic target for regulating inflammatory response in α-syn models PD.
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224
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Wang Q, Liu Y, Zhou J. Neuroinflammation in Parkinson's disease and its potential as therapeutic target. Transl Neurodegener 2015; 4:19. [PMID: 26464797 PMCID: PMC4603346 DOI: 10.1186/s40035-015-0042-0] [Citation(s) in RCA: 543] [Impact Index Per Article: 60.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 10/01/2015] [Indexed: 01/19/2023] Open
Abstract
Parkinson’s disease (PD), the second most common age-associated neurodegenerative disorder, is characterized by the loss of dopaminergic (DA) neurons and the presence of α-synuclein-containing aggregates in the substantia nigra pars compacta (SNpc). Chronic neuroinflammation is one of the hallmarks of PD pathophysiology. Post-mortem analyses of human PD patients and experimental animal studies indicate that activation of glial cells and increases in pro-inflammatory factor levels are common features of the PD brain. Chronic release of pro-inflammatory cytokines by activated astrocytes and microglia leads to the exacerbation of DA neuron degeneration in the SNpc. Besides, peripheral immune system is also implicated in the pathogenesis of PD. Infiltration and accumulation of immune cells from the periphery are detected in and around the affected brain regions of PD patients. Moreover, inflammatory processes have been suggested as promising interventional targets for PD and even other neurodegenerative diseases. A better understanding of the role of inflammation in PD will provide new insights into the pathological processes and help to establish effective therapeutic strategies. In this review, we will summarize recent progresses in the neuroimmune aspects of PD and highlight the potential therapeutic interventions targeting neuroinflammation.
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Affiliation(s)
- Qinqin Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031 China
| | - Yingjun Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031 China
| | - Jiawei Zhou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031 China
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225
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CX3CL1/CX3CR1-mediated microglia activation plays a detrimental role in ischemic mice brain via p38MAPK/PKC pathway. J Cereb Blood Flow Metab 2015; 35:1623-31. [PMID: 25966946 PMCID: PMC4640309 DOI: 10.1038/jcbfm.2015.97] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 04/08/2015] [Accepted: 04/13/2015] [Indexed: 02/07/2023]
Abstract
The exact roles of activated microglia and fractalkine (CX3CL1)/fractalkine receptor (CX3CR1) signaling are not fully understood in brain ischemic injury and the findings reported are controversial. Here, we investigated the effects of CX3CR1 siRNA on the expression of CX3CR1, p38 mitogen-activated protein kinase (p38MAPK), Protein Kinase C (PKC) and inflammatory cytokines, microglia activation, white matter lesions, and cognitive function in mice treated with bilateral common carotid artery stenosis (BCAS) in vivo as well as effects of exogenous CX3CL1, CX3CR1 siRNA, and SB2035080 on expression of inflammatory cytokines in BV2 microglia treated with oxygen-glucose deprivation (OGD) in vitro. We showed that CX3CR1 siRNA significantly inhibited the increased expression of CX3CR1, p38MAPK, PKC as well as tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6, and also attenuated microglia activation, white matter lesions, and cognitive deficits induced by BCAS in mice brain. We also showed that exogenous CX3CL1 could induce a further enhancement in TNF-α and IL-1β expression, which could be suppressed by CX3CR1 siRNA or by the p38MAPK inhibitor in OGD-treated BV2 microglial cells in vitro. Our findings indicated that CX3CL1/CX3CR1-mediated microglial activation plays a detrimental role in ischemic brain via p38MAPK/PKC signaling and also suggested that CX3CL1/CX3CR1 axis might be a putative therapeutic target to disrupt the cascade of deleterious events that lead to brain ischemic injury.
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226
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Flowers A, Lee JY, Acosta S, Hudson C, Small B, Sanberg CD, Bickford PC. NT-020 treatment reduces inflammation and augments Nrf-2 and Wnt signaling in aged rats. J Neuroinflammation 2015; 12:174. [PMID: 26376629 PMCID: PMC4574066 DOI: 10.1186/s12974-015-0395-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 09/09/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Aging is associated with a decline in stem cell proliferation that is thought to be a result of dysregulated signaling in the neurogenic niche. This results in a diminished and less efficient pool of progenitors. The Wnt pathway plays a key role in the proliferation and differentiation of progenitor cells. Recent publications suggest that the age-related decline in the function of Wnt is a contributor to age-dependent decline in neural progenitors. Similarly, the aged neurogenic niche is characterized by higher levels of inflammatory cytokines. This increased inflammation contributes to the declining function of neural progenitor cells. NT-020, a proprietary blend of polyphenols, has been shown to increase proliferation of neural progenitors and improve cognitive function in aged rats. PURPOSE AND METHODS In this study, we examined the neurogenic niche in the subgranular zone of the dentate gyrus (SGZ) and the subventricular zone (SVZ) of young and aged rats to determine if dietary supplementation with NT-020 could regulate inflammation and oxidative stress response pathways in neurons, astrocytes, and microglia. Further, we examined NT-020's ability to modulate Wnt signaling in the aged neurogenic niche. To accomplish this, we utilized gene PCR arrays and immunohistochemistry. RESULTS We observed an increase in nuclear localization of immunopositive labeling of β-catenin, HO-1, and Nrf2 in all subsets of cell types in both young and aged rats in the SGZ and SVZ following NT-020 treatment. NeuN-positive cells showed a basal increase in nuclear β-catenin in the aged rats, which was not observed in doublecortin (DCX)-labeled cells, microglia, or astrocytes. Reverse transcription polymerase chain reaction (RT-PCR) analysis of isolated hippocampal tissue revealed that a significant percent of genes involved with inflammation are affected by treatment with NT-020. In addition, several genes that regulate Wnt activity were affected by supplementation. CONCLUSIONS The results suggest that NT-020 activates oxidative stress response pathways and supports pro-neurogenic gene expression in the hippocampus. This may represent the mechanism by which the NT-020 formula enhances performance in learning and memory tasks in aged mice.
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Affiliation(s)
- Antwoine Flowers
- Department of Neurosurgery Brain Repair, and Center of Excellence for Aging and Brain Repair, University of South Florida Morsani College of Medicine, MDC-78, 12901 Bruce B Downs, Blvd, Tampa, FL, 33612, USA.
| | - Jea-Young Lee
- Department of Neurosurgery Brain Repair, and Center of Excellence for Aging and Brain Repair, University of South Florida Morsani College of Medicine, MDC-78, 12901 Bruce B Downs, Blvd, Tampa, FL, 33612, USA.
| | - Sandra Acosta
- Department of Neurosurgery Brain Repair, and Center of Excellence for Aging and Brain Repair, University of South Florida Morsani College of Medicine, MDC-78, 12901 Bruce B Downs, Blvd, Tampa, FL, 33612, USA.
| | - Charles Hudson
- Research Service, James A Haley Veterans Hospital, Tampa, FL, USA.
| | - Brent Small
- School of Aging Studies, University of South Florida, 4202 E. Fowler Ave, Tampa, FL, 33620, USA.
| | | | - Paula C Bickford
- Department of Neurosurgery Brain Repair, and Center of Excellence for Aging and Brain Repair, University of South Florida Morsani College of Medicine, MDC-78, 12901 Bruce B Downs, Blvd, Tampa, FL, 33612, USA. .,Research Service, James A Haley Veterans Hospital, Tampa, FL, USA.
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227
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Stuart MJ, Singhal G, Baune BT. Systematic Review of the Neurobiological Relevance of Chemokines to Psychiatric Disorders. Front Cell Neurosci 2015; 9:357. [PMID: 26441528 PMCID: PMC4564736 DOI: 10.3389/fncel.2015.00357] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 08/26/2015] [Indexed: 12/13/2022] Open
Abstract
Psychiatric disorders are highly prevalent and disabling conditions of increasing public health relevance. Much recent research has focused on the role of cytokines in the pathophysiology of psychiatric disorders; however, the related family of immune proteins designated chemokines has been relatively neglected. Chemokines were originally identified as having chemotactic function on immune cells; however, recent evidence has begun to elucidate novel, brain-specific functions of these proteins of relevance to the mechanisms of psychiatric disorders. A systematic review of both human and animal literature in the PubMed and Google Scholar databases was undertaken. After application of all inclusion and exclusion criteria, 157 references were remained for the review. Some early mechanistic evidence does associate select chemokines with the neurobiological processes, including neurogenesis, modulation of the neuroinflammatory response, regulation of the hypothalamus–pituitary–adrenal axis, and modulation of neurotransmitter systems. This early evidence however does not clearly demonstrate any specificity for a certain psychiatric disorder, but is primarily relevant to mechanisms which are shared across disorders. Notable exceptions include CCL11 that has recently been shown to impair hippocampal function in aging – of distinct relevance to Alzheimer’s disease and depression in the elderly, and pre-natal exposure to CXCL8 that may disrupt early neurodevelopmental periods predisposing to schizophrenia. Pro-inflammatory chemokines, such as CCL2, CCL7, CCL8, CCL12, and CCL13, have been shown to drive chemotaxis of pro-inflammatory cells to the inflamed or injured CNS. Likewise, CX3CL has been implicated in promoting glial cells activation, pro-inflammatory cytokines secretion, expression of ICAM-1, and recruitment of CD4+ T-cells into the CNS during neuroinflammatory processes. With further translational research, chemokines may present novel diagnostic and/or therapeutic targets in psychiatric disorders.
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Affiliation(s)
- Michael J Stuart
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, University of Adelaide , Adelaide, SA , Australia ; School of Medicine, University of Queensland , Brisbane, QLD , Australia
| | - Gaurav Singhal
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, University of Adelaide , Adelaide, SA , Australia
| | - Bernhard T Baune
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, University of Adelaide , Adelaide, SA , Australia
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228
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Le Thuc O, Blondeau N, Nahon JL, Rovère C. The complex contribution of chemokines to neuroinflammation: switching from beneficial to detrimental effects. Ann N Y Acad Sci 2015; 1351:127-40. [PMID: 26251227 DOI: 10.1111/nyas.12855] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Inflammation is an innate mechanism that defends organisms against harmful stimuli. Inflammation leads to the production and secretion of proinflammatory mediators that activate and recruit immune cells to damaged tissues, including the brain, to resolve the cause of inflammation. In the central nervous system, inflammation is referred to as neuroinflammation, which occurs in various pathological conditions of the brain. The primary role of neuroinflammation is to protect the brain. However, prolonged and/or inappropriate inflammation can be harmful for the brain, from individual cells to the whole tissue. This review focuses on a particular type of inflammatory mediator, chemokines, and describes their complex effects both under physiological and pathophysiological conditions of the brain. The clinical relevance of the multiple characters of chemokines is highlighted with respect to acute and chronic inflammation of the brain, including their actions in stroke and Alzheimer's disease, respectively.
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Affiliation(s)
- Ophélia Le Thuc
- Université de Nice Sophia Antipolis, Nice, France, and Centre National de la Recherche Scientifique (CNRS), Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Nicolas Blondeau
- Université de Nice Sophia Antipolis, Nice, France, and Centre National de la Recherche Scientifique (CNRS), Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Jean-Louis Nahon
- Université de Nice Sophia Antipolis, Nice, France, and Centre National de la Recherche Scientifique (CNRS), Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Carole Rovère
- Université de Nice Sophia Antipolis, Nice, France, and Centre National de la Recherche Scientifique (CNRS), Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
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229
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Fractalkine Signaling and Microglia Functions in the Developing Brain. Neural Plast 2015; 2015:689404. [PMID: 26347402 PMCID: PMC4539507 DOI: 10.1155/2015/689404] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 04/29/2015] [Indexed: 01/05/2023] Open
Abstract
Microglial cells are the resident macrophages of the central nervous system (CNS). Besides their classical roles in pathological conditions, these immune cells also dynamically interact with neurons and influence their structure and function in physiological conditions. The neuronal chemokine fractalkine and its microglial receptor CX3CR1 are one important signaling pathway involved in these reciprocal interactions. In the present review, we will discuss recent evidence indicating that fractalkine signaling also determines several functions of microglial cells during normal CNS development. It has been known for a decade that microglial cells influence the neuronal death that normally occurs during CNS development. Surprisingly, recent evidence indicates that they can also support survival of developing neurons, control axon outgrowth, and laminar positioning of subsets of interneurons in the forebrain. Moreover, microglial cells influence the maturation of synaptic circuits at early postnatal stages: their phagocytic activity allows them to eliminate inappropriate synapses and they can also influence the functional expression of synaptic proteins by releasing mediators. Fractalkine signaling controls these functions of microglial cells in part by regulating their timely recruitment at sites of developing synapses. Finally, on-going research suggests that this signaling pathway is also a key player in neurodevelopmental disorders.
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230
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Plasma and Cerebrospinal Fluid Biomarkers Predict Cerebral Injury in HIV-Infected Individuals on Stable Combination Antiretroviral Therapy. J Acquir Immune Defic Syndr 2015; 69:29-35. [PMID: 25622053 DOI: 10.1097/qai.0000000000000532] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
OBJECTIVES HIV-associated brain injury persists despite combination antiretroviral therapy, but contributing factors remain poorly understood. We postulated that inflammation-associated biomarkers will be associated with cerebral injury on proton magnetic resonance spectroscopy in chronically HIV-infected subjects. METHODS Five biomarkers were measured in 197 HIV-infected subjects: soluble CD14, MCP-1, IP-10, MIP-1β, and fractalkine. Levels of N-acetyl aspartate (NAA), Choline (Cho), Myoinositol (MI), Glutamate + Glutamine (Glx), and Creatine (Cr) were acquired in the midfrontal cortex (MFC), frontal white matter, and basal ganglia (BG). Predictive models were built through linear regression, and the best models were chosen using the Akaike Information Criterion. RESULTS Increases in plasma or CSF MCP-1 were associated with lower NAA/Cr in the MFC and BG, whereas metabolite changes in the frontal white matter for NAA/Cr, GlxCr, and Cho/Cr were explained almost exclusively by a single factor, sCD14. Plasma and CSF levels of this factor were also significantly associated with Glx/Cr in MFC and BG. Higher CSF FKN was associated with higher NAA/Cr in BG. Best predictors for higher Cho/Cr in BG and MFC were CSF sCD14 and CSF MIP-1β. Plasma and CSF IP-10 were only associated with Cho/Cr in MFC. Of the 3 models that simultaneously accounted for both plasma and CSF, there were more associations between CSF biomarkers and magnetic resonance spectroscopy metabolites. CONCLUSIONS Markers of inflammation and immune activation, in particular MCP-1 and sCD14, predominantly reflecting CNS sources, contribute to the persistence of brain injury in a metabolite and region-dependent manner in chronically HIV-infected patients on stable combination antiretroviral therapy.
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231
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CX3CL1/CX3CR1 Axis Plays a Key Role in Ischemia-Induced Oligodendrocyte Injury via p38MAPK Signaling Pathway. Mol Neurobiol 2015; 53:4010-4018. [DOI: 10.1007/s12035-015-9339-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/01/2015] [Indexed: 12/13/2022]
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Saba LM, Flink SC, Vanderlinden LA, Israel Y, Tampier L, Colombo G, Kiianmaa K, Bell RL, Printz MP, Flodman P, Koob G, Richardson HN, Lombardo J, Hoffman PL, Tabakoff B. The sequenced rat brain transcriptome--its use in identifying networks predisposing alcohol consumption. FEBS J 2015; 282:3556-78. [PMID: 26183165 DOI: 10.1111/febs.13358] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 06/10/2015] [Accepted: 06/23/2015] [Indexed: 01/01/2023]
Abstract
UNLABELLED A quantitative genetic approach, which involves correlation of transcriptional networks with the phenotype in a recombinant inbred (RI) population and in selectively bred lines of rats, and determination of coinciding quantitative trait loci for gene expression and the trait of interest, has been applied in the present study. In this analysis, a novel approach was used that combined DNA-Seq data, data from brain exon array analysis of HXB/BXH RI rat strains and six pairs of rat lines selectively bred for high and low alcohol preference, and RNA-Seq data (including rat brain transcriptome reconstruction) to quantify transcript expression levels, generate co-expression modules and identify biological functions that contribute to the predisposition of consuming varying amounts of alcohol. A gene co-expression module was identified in the RI rat strains that contained both annotated and unannotated transcripts expressed in the brain, and was associated with alcohol consumption in the RI panel. This module was found to be enriched with differentially expressed genes from the selected lines of rats. The candidate genes within the module and differentially expressed genes between high and low drinking selected lines were associated with glia (microglia and astrocytes) and could be categorized as being related to immune function, energy metabolism and calcium homeostasis, as well as glial-neuronal communication. The results of the present study show that there are multiple combinations of genetic factors that can produce the same phenotypic outcome. Although no single gene accounts for predisposition to a particular level of alcohol consumption in every animal model, coordinated differential expression of subsets of genes in the identified pathways produce similar phenotypic outcomes. DATABASE The datasets supporting the results of the present study are available at http://phenogen.ucdenver.edu.
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Affiliation(s)
- Laura M Saba
- Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO, USA
| | - Stephen C Flink
- Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO, USA
| | - Lauren A Vanderlinden
- Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO, USA
| | - Yedy Israel
- Laboratory of Pharmacogenetics of Alcoholism, Molecular & Clinical Pharmacology Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Lutske Tampier
- Laboratory of Pharmacogenetics of Alcoholism, Molecular & Clinical Pharmacology Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Giancarlo Colombo
- Neuroscience Institute, National Research Council of Italy, Section of Cagliari, Monserrato, Italy
| | - Kalervo Kiianmaa
- Department of Alcohol, Drugs and Addiction, National Institute for Health and Welfare, Helsinki, Finland
| | - Richard L Bell
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Morton P Printz
- Department of Pharmacology, University of California San Diego, La Jolla, CA, USA
| | - Pamela Flodman
- Department of Pediatrics, University of California, Irvine, Irvine, CA, USA
| | - George Koob
- Committee on the Neurobiology of Addiction Disorders, The Scripps Research Institute, La Jolla, CA, USA
| | - Heather N Richardson
- Committee on the Neurobiology of Addiction Disorders, The Scripps Research Institute, La Jolla, CA, USA
| | - Joseph Lombardo
- National Supercomputing Center for Energy and Environment, University of Nevada, Las Vegas, Nevada, USA
| | - Paula L Hoffman
- Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO, USA.,Department of Pharmacology, University of Colorado Denver, Aurora, CO, USA
| | - Boris Tabakoff
- Department of Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO, USA.,Department of Pharmacology, University of Colorado Denver, Aurora, CO, USA
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233
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Vecino E, Rodriguez FD, Ruzafa N, Pereiro X, Sharma SC. Glia-neuron interactions in the mammalian retina. Prog Retin Eye Res 2015; 51:1-40. [PMID: 26113209 DOI: 10.1016/j.preteyeres.2015.06.003] [Citation(s) in RCA: 493] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 05/18/2015] [Accepted: 06/02/2015] [Indexed: 02/07/2023]
Abstract
The mammalian retina provides an excellent opportunity to study glia-neuron interactions and the interactions of glia with blood vessels. Three main types of glial cells are found in the mammalian retina that serve to maintain retinal homeostasis: astrocytes, Müller cells and resident microglia. Müller cells, astrocytes and microglia not only provide structural support but they are also involved in metabolism, the phagocytosis of neuronal debris, the release of certain transmitters and trophic factors and K(+) uptake. Astrocytes are mostly located in the nerve fibre layer and they accompany the blood vessels in the inner nuclear layer. Indeed, like Müller cells, astrocytic processes cover the blood vessels forming the retinal blood barrier and they fulfil a significant role in ion homeostasis. Among other activities, microglia can be stimulated to fulfil a macrophage function, as well as to interact with other glial cells and neurons by secreting growth factors. This review summarizes the main functional relationships between retinal glial cells and neurons, presenting a general picture of the retina recently modified based on experimental observations. The preferential involvement of the distinct glia cells in terms of the activity in the retina is discussed, for example, while Müller cells may serve as progenitors of retinal neurons, astrocytes and microglia are responsible for synaptic pruning. Since different types of glia participate together in certain activities in the retina, it is imperative to explore the order of redundancy and to explore the heterogeneity among these cells. Recent studies revealed the association of glia cell heterogeneity with specific functions. Finally, the neuroprotective effects of glia on photoreceptors and ganglion cells under normal and adverse conditions will also be explored.
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Affiliation(s)
- Elena Vecino
- Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, Leioa 48940, Vizcaya, Spain
| | - F David Rodriguez
- Department of Biochemistry and Molecular Biology, E-37007, University of Salamanca, Salamanca, Spain
| | - Noelia Ruzafa
- Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, Leioa 48940, Vizcaya, Spain
| | - Xandra Pereiro
- Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, Leioa 48940, Vizcaya, Spain
| | - Sansar C Sharma
- Department of Ophthalmology, Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595, USA; IKERBASQUE, Basque Foundation for Science at Dept. Cell Biology and Histology, UPV/EHU, Spain
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234
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Maphis N, Xu G, Kokiko-Cochran ON, Cardona AE, Ransohoff RM, Lamb BT, Bhaskar K. Loss of tau rescues inflammation-mediated neurodegeneration. Front Neurosci 2015; 9:196. [PMID: 26089772 PMCID: PMC4452825 DOI: 10.3389/fnins.2015.00196] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 05/18/2015] [Indexed: 12/20/2022] Open
Abstract
Neuroinflammation is one of the neuropathological hallmarks of Alzheimer's disease (AD) and related tauopathies. Activated microglia spatially coexist with microtubule-associated protein tau (Mapt or tau)-burdened neurons in the brains of human AD and non-AD tauopathies. Numerous studies have suggested that neuroinflammation precedes tau pathology and that induction or blockage of neuroinflammation via lipopolysaccharide (LPS) or anti-inflammatory compounds (such as FK506) accelerate or block tau pathology, respectively in several animal models of tauopathy. We have previously demonstrated that microglia-mediated neuroinflammation via deficiency of the microglia-specific chemokine (fractalkine) receptor, CX3CR1, promotes tau pathology and neurodegeneration in a mouse model of LPS-induced systemic inflammation. Here, we demonstrate that tau mediates the neurotoxic effects of LPS in Cx3cr1 (-/-) mice. First, Mapt (+/+) neurons displayed elevated levels of Annexin V (A5) and TUNEL (markers of neurodegeneration) when co-cultured with LPS-treated Cx3cr1 (-/-)microglia, which is rescued in Mapt (-/-) neurons. Second, a neuronal population positive for phospho-S199 (AT8) tau in the dentate gyrus is also positive for activated or cleaved caspase (CC3) in the LPS-treated Cx3cr1 (-/-) mice. Third, genetic deficiency for tau in Cx3cr1 (-/-) mice resulted in reduced microglial activation, altered expression of inflammatory genes and a significant reduction in the number of neurons positive for CC3 compared to Cx3cr1 (-/-)mice. Finally, Cx3cr1 (-/-)mice exposed to LPS displayed a lack of inhibition in an open field exploratory behavioral test, which is rescued by tau deficiency. Taken together, our results suggest that pathological alterations in tau mediate inflammation-induced neurotoxicity and that deficiency of Mapt is neuroprotective. Thus, therapeutic approaches toward either reducing tau levels or blocking neuroinflammatory pathways may serve as a potential strategy in treating tauopathies.
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Affiliation(s)
- Nicole Maphis
- Department of Molecular Genetics and Microbiology, University of New Mexico Albuquerque, NM, USA
| | - Guixiang Xu
- Department of Neurosciences, Cleveland Clinic Foundation Cleveland, OH, USA
| | | | - Astrid E Cardona
- Department of Biology, University of Texas at San Antonio San Antonio, TX, USA
| | | | - Bruce T Lamb
- Department of Neurosciences, Cleveland Clinic Foundation Cleveland, OH, USA
| | - Kiran Bhaskar
- Department of Molecular Genetics and Microbiology, University of New Mexico Albuquerque, NM, USA
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235
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The Effect of PSD-93 Deficiency on the Expression of Early Inflammatory Cytokines Induced by Ischemic Brain Injury. Cell Biochem Biophys 2015; 73:695-700. [DOI: 10.1007/s12013-015-0666-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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236
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Abstract
This review summarizes and organizes the literature concerning the effects of microglia on neurogenesis, particularly focusing on the subgranular zone (SGZ) of the hippocampus and subventricular zone (SVZ) of the lateral ventricles, in which the neurogenic potential is progressively restricted during the life of the organism. A comparison of microglial roles in neurogenesis in these two regions indicates that microglia regulate neurogenesis in a temporally and spatially specific manner. Microglia may also sense signals from the surrounding environment and have regulatory effects on neurogenesis. We speculate microglia function as a hub for the information obtained from the inner and outer brain regions for regulating neurogenesis.
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Affiliation(s)
- Kaoru Sato
- Division of Pharmacology, Laboratory of Neuropharmacology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-Ku, Tokyo, 158-8501, Japan
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237
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Valera E, Mante M, Anderson S, Rockenstein E, Masliah E. Lenalidomide reduces microglial activation and behavioral deficits in a transgenic model of Parkinson's disease. J Neuroinflammation 2015; 12:93. [PMID: 25966683 PMCID: PMC4432827 DOI: 10.1186/s12974-015-0320-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 05/05/2015] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Parkinson's disease (PD) is one of the most common causes of dementia and motor deficits in the elderly. PD is characterized by the abnormal accumulation of the synaptic protein alpha-synuclein (α-syn) and degeneration of dopaminergic neurons in substantia nigra, which leads to neurodegeneration and neuroinflammation. Currently, there are no disease modifying alternatives for PD; however, targeting neuroinflammation might be a viable option for reducing motor deficits and neurodegeneration. Lenalidomide is a thalidomide derivative designed for reduced toxicity and increased immunomodulatory properties. Lenalidomide has shown protective effects in an animal model of amyotrophic lateral sclerosis, and its mechanism of action involves modulation of cytokine production and inhibition of NF-κB signaling. METHODS In order to assess the effect of lenalidomide in an animal model of PD, mThy1-α-syn transgenic mice were treated with lenalidomide or the parent molecule thalidomide at 100 mg/kg for 4 weeks. RESULTS Lenalidomide reduced motor behavioral deficits and ameliorated dopaminergic fiber loss in the striatum. This protective action was accompanied by a reduction in microgliosis both in striatum and hippocampus. Central expression of pro-inflammatory cytokines was diminished in lenalidomide-treated transgenic animals, together with reduction in NF-κB activation. CONCLUSION These results support the therapeutic potential of lenalidomide for reducing maladaptive neuroinflammation in PD and related neuropathologies.
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Affiliation(s)
- Elvira Valera
- Department of Neurosciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA.
| | - Michael Mante
- Department of Neurosciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA.
| | - Scott Anderson
- Department of Neurosciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA.
| | - Edward Rockenstein
- Department of Neurosciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA.
| | - Eliezer Masliah
- Department of Neurosciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA. .,Department of Pathology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA.
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238
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Maphis N, Xu G, Kokiko-Cochran ON, Jiang S, Cardona A, Ransohoff RM, Lamb BT, Bhaskar K. Reactive microglia drive tau pathology and contribute to the spreading of pathological tau in the brain. Brain 2015; 138:1738-55. [PMID: 25833819 DOI: 10.1093/brain/awv081] [Citation(s) in RCA: 373] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 01/27/2015] [Indexed: 12/14/2022] Open
Abstract
Pathological aggregation of tau is a hallmark of Alzheimer's disease and related tauopathies. We have previously shown that the deficiency of the microglial fractalkine receptor (CX3CR1) led to the acceleration of tau pathology and memory impairment in an hTau mouse model of tauopathy. Here, we show that microglia drive tau pathology in a cell-autonomous manner. First, tau hyperphosphorylation and aggregation occur as early as 2 months of age in hTauCx3cr1(-/-) mice. Second, CD45(+) microglial activation correlates with the spatial memory deficit and spread of tau pathology in the anatomically connected regions of the hippocampus. Third, adoptive transfer of purified microglia derived from hTauCx3cr1(-/-) mice induces tau hyperphosphorylation within the brains of non-transgenic recipient mice. Finally, inclusion of interleukin 1 receptor antagonist (Kineret®) in the adoptive transfer inoculum significantly reduces microglia-induced tau pathology. Together, our results suggest that reactive microglia are sufficient to drive tau pathology and correlate with the spread of pathological tau in the brain.
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Affiliation(s)
- Nicole Maphis
- 1 Department of Molecular Genetics and Microbiology, MSC08 4660, 1 University of New Mexico, University of New Mexico, Albuquerque NM 87131, USA
| | - Guixiang Xu
- 2 Department of Neurosciences, NC30, 9500 Euclid Avenue, Cleveland Clinic, Cleveland OH 44195, USA
| | - Olga N Kokiko-Cochran
- 2 Department of Neurosciences, NC30, 9500 Euclid Avenue, Cleveland Clinic, Cleveland OH 44195, USA
| | - Shanya Jiang
- 1 Department of Molecular Genetics and Microbiology, MSC08 4660, 1 University of New Mexico, University of New Mexico, Albuquerque NM 87131, USA
| | - Astrid Cardona
- 3 Department of Biology, University of Texas San Antonio, West Campus/Tobin lab MBT 1.216, San Antonio TX 78249, USA
| | | | - Bruce T Lamb
- 2 Department of Neurosciences, NC30, 9500 Euclid Avenue, Cleveland Clinic, Cleveland OH 44195, USA
| | - Kiran Bhaskar
- 1 Department of Molecular Genetics and Microbiology, MSC08 4660, 1 University of New Mexico, University of New Mexico, Albuquerque NM 87131, USA
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239
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Hu HX, Lin RH, Zhu XQ, Li ZF, Chen LD. Anti-inflammatory effects of Gualou Guizhi decoction in transient focal cerebral ischemic brains. [Corrected]. Mol Med Rep 2015; 12:1321-7. [PMID: 25815521 DOI: 10.3892/mmr.2015.3511] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 02/20/2015] [Indexed: 11/05/2022] Open
Abstract
The aim of the present study was to explore the neuroprotective effects of Gualou Guizhi decoction (GLGZD) in a rat model of middle cerebral artery occlusion (MCAO). Sprague-Dawley rats were divided into three groups: Sham (no MCAO), MCAO (MCAO with no GLGZD treatment) and GLGZD (MCAO with GLGZD treatment). Rats in the MCAO and GLGZD groups were subjected to permanent occlusion of the left middle cerebral artery. Neurological function and infarct volume were measured. Microglial activation and inflammatory cell accumulation were measured using immunohistochemistry. mRNA and protein expression of inflammatory mediators were examined using reverse transcription-quantitative polymerase chain reaction and an enzyme-linked immunosorbent assay. The expression of proteins associated with the nuclear factor κ-B (NF-κB) inflammation signaling pathway was analyzed using western blotting. The results of the present study suggested that infarct size was significantly reduced and neurological behavior function was improved in rats with MCAO treated with GLGZD compared with rats in the MCAO group. Amoeboid microglial expansion and inflammatory cell migration were observed in the infarcted areas of rats in the GLGZD group and were not identified in those of the MCAO group. Target mRNA and protein levels, and inflammatory cell infiltration were significantly reduced in the GLGZD group compared with the MCAO model group. Notably, GLGZD treatment induced neuroprotective effects, reducing inflammation and inhibiting NF-κB signaling compared with the MCAO group. Therefore, GLGZD may exhibit anti-inflammatory effects against ischemia-reperfusion brain injury and may be a therapeutic target for ischemic stroke.
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Affiliation(s)
- Hai Xia Hu
- Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350108, P.R. China
| | - Ru Hui Lin
- Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350108, P.R. China
| | - Xiao Qin Zhu
- Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350108, P.R. China
| | - Zuan Fang Li
- Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350108, P.R. China
| | - Li Dian Chen
- College of Rehabilitation Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350108, P.R. China
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240
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Zhang Y, Zheng J, Zhou Z, Zhou H, Wang Y, Gong Z, Zhu J. Fractalkine promotes chemotaxis of bone marrow-derived mesenchymal stem cells towards ischemic brain lesions through Jak2 signaling and cytoskeletal reorganization. FEBS J 2015; 282:891-903. [PMID: 25559502 DOI: 10.1111/febs.13187] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 12/01/2014] [Accepted: 12/27/2014] [Indexed: 12/19/2022]
Abstract
The fractalkine (FKN)-CX3CR1 (FKN receptor) axis reportedly plays an important role in the progression of many neural pathologies. However, its role in the recruitment of bone marrow-derived progenitor cells for neurogenesis remains elusive. The chemokine-based mechanism underlying the migration of bone marrow-derived mesenchymal stem cells (BMSCs) was investigated in a double-chamber transmigration model with recombinant FKN and endogenous FKN extract, and the results confirmed the involvement of FKN in migration. This chemotactic response was CX3CR1-dependent and FKN-sensitive. Western blotting, immunoprecipitation and transmigration assays revealed that the Janus kinase (Jak)2-signal transducer and activator of transcription (Stat)5α-extracellular signal-related kinase (ERK)1/2 pathway was activated by FKN. Confocal laser scanning microscopy was used to demonstrate cytoskeletal reorganization caused by remodeling of the surface receptor integrin α5β1, intracellular phosphorylation of Fak and Pax, and upregulation of intercellular adhesion molecule-1 during BMSC migration. Moreover, significant inhibition of signaling and migration was detected after treatment of cells with Jak2-interfering RNA or the antagonist AG490. In addition, the results of a fluorescence immunohistochemical analysis of an in vivo chemotactic model, developed via transplantation of BMSCs into transient middle cerebral artery-occluded rats, were consistent with the in vitro results. These findings suggest that FKN activates Jak2-Stat5α-ERK1/2 signaling through CX3CR1, thereby triggering integrin-dependent machinery reorganization to allow chemotactic migration of BMSCs towards an ischemic cerebral lesion.
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Affiliation(s)
- Yuan Zhang
- Department of Orthopedics, Xinqiao Hospital, Third Military Medical University, Chongqing, China
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241
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Strobel S, Grünblatt E, Riederer P, Heinsen H, Arzberger T, Al-Sarraj S, Troakes C, Ferrer I, Monoranu CM. Changes in the expression of genes related to neuroinflammation over the course of sporadic Alzheimer's disease progression: CX3CL1, TREM2, and PPARγ. J Neural Transm (Vienna) 2015; 122:1069-76. [PMID: 25596843 DOI: 10.1007/s00702-015-1369-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 01/12/2015] [Indexed: 12/28/2022]
Abstract
The role of neuroinflammation in the pathogenesis of neurodegenerative diseases has become more evident in recent years. Research on the etiology and pathogenesis of sporadic Alzheimer's disease (AD) has focused on the role of chemokines such as CX3CL1, on the triggering receptors expressed by myeloid cells (TREMs), especially TREM2, and on the transcription factor/nuclear hormone receptor peroxisome proliferator-activated receptor gamma (PPARγ). Here we analyzed the expression levels of CX3CL1, TREM2, and PPARγ in tissue homogenates from human brain regions that have different degrees of vulnerability to neuropathological AD-related changes to obtain insights into the pathogenesis and progression of AD. We found that CX3CL1 and TREM2, two genes related to neuroinflammation, are more highly expressed in brain regions with pronounced vulnerability to AD-related changes, such as the hippocampus, and that the expression levels reflect the course of the disease, whereas regions with low vulnerability to AD, seemed generally less affected by neuroinflammation. Furthermore, our results support previous findings of significantly higher CX3CL1 plasma levels in patients with mild to moderate AD than in patients with severe AD. Thus, CX3CL1 should be considered as promising additional marker for the early diagnosis of AD and underlines once more, the involvement of the neuroinflammation in the pathogenesis of this neurodegenerative disease.
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Affiliation(s)
- S Strobel
- Department of Neuropathology, Institute of Pathology, University of Wuerzburg, Josef-Schneider-Str. 2, 97080, Wuerzburg, Germany
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242
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Cytokine Serum Levels as Potential Biological Markers for the Psychopathology in Schizophrenia. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/493505] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We discuss the role of immune system disturbance in schizophrenia and especially changes of serum levels of cytokines in patients with schizophrenia. The cytokines are essential to wide range of functions related to the defense of the organisms from infectious and environmental dangers. However it is not known whether cytokines influence the presentation of psychotic symptoms. Identification of changes in the serum level of certain cytokines and their correlation with distinct psychopathological symptoms may facilitate the identification of subgroups of patients who are likely to benefit from immunotherapy or anti-inflammatory therapy. Such patients may benefit from tailored immunotherapy designed for modulation of abnormal cytokine levels related to specific positive or negative symptoms of schizophrenia.
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243
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Ali I, Chugh D, Ekdahl CT. Role of fractalkine-CX3CR1 pathway in seizure-induced microglial activation, neurodegeneration, and neuroblast production in the adult rat brain. Neurobiol Dis 2014; 74:194-203. [PMID: 25461978 DOI: 10.1016/j.nbd.2014.11.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 10/21/2014] [Accepted: 11/12/2014] [Indexed: 10/24/2022] Open
Abstract
Temporal lobe seizures lead to an acute inflammatory response in the brain primarily characterized by activation of parenchymal microglial cells. Simultaneously, degeneration of pyramidal cells and interneurons is evident together with a seizure-induced increase in the production of new neurons within the dentate gyrus of the hippocampus. We have previously shown a negative correlation between the acute seizure-induced inflammation and the survival of newborn hippocampal neurons. Here, we aimed to evaluate the role of the fractalkine-CX3CR1 pathway for these acute events. Fractalkine is a chemokine expressed by both neurons and glia, while its receptor, CX3CR1 is primarily expressed on microglia. Electrically-induced partial status epilepticus (SE) was induced in adult rats through stereotaxically implanted electrodes in the hippocampus. Recombinant rat fractalkine or CX3CR1 antibody was infused intraventricularly during one week post-SE. A significant increase in the expression of CX3CR1, but not fractalkine, was observed in the dentate gyrus at one week. CX3CR1 antibody treatment resulted in a reduction in microglial activation, neurodegeneration, as well as neuroblast production. In contrast, fractalkine treatment had only minor effects. This study provides evidence for a role of the fractalkine-CX3CR1 signaling pathway in seizure-induced microglial activation and suggests that neuroblast production following seizures may partly occur as a result of microglial activation.
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Affiliation(s)
- Idrish Ali
- Inflammation and Stem Cell Therapy Group, Wallenberg Neuroscience Center, Division of Clinical Neurophysiology, Lund University, Sweden; Lund Epilepsy Center, Lund University, SE-221 84 Lund, Sweden
| | - Deepti Chugh
- Inflammation and Stem Cell Therapy Group, Wallenberg Neuroscience Center, Division of Clinical Neurophysiology, Lund University, Sweden; Lund Epilepsy Center, Lund University, SE-221 84 Lund, Sweden
| | - Christine T Ekdahl
- Inflammation and Stem Cell Therapy Group, Wallenberg Neuroscience Center, Division of Clinical Neurophysiology, Lund University, Sweden; Lund Epilepsy Center, Lund University, SE-221 84 Lund, Sweden.
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244
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Gullo F, Amadeo A, Donvito G, Lecchi M, Costa B, Constanti A, Wanke E. Atypical "seizure-like" activity in cortical reverberating networks in vitro can be caused by LPS-induced inflammation: a multi-electrode array study from a hundred neurons. Front Cell Neurosci 2014; 8:361. [PMID: 25404893 PMCID: PMC4217498 DOI: 10.3389/fncel.2014.00361] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 10/13/2014] [Indexed: 12/21/2022] Open
Abstract
We show here that a mild sterile inflammation induced by the endotoxin lipopolysaccharide (LPS), in a neuron/astrocyte/microglial cortical network, modulates neuronal excitability and can initiate long-duration burst events resembling epileptiform seizures, a recognized feature of various central nervous neurodegenerative, neurological and acute systemic diseases associated with neuroinflammation. To study this action, we simultaneously analyzed the reverberating bursting activity of a hundred neurons by using in vitro multi-electrode array methods. ∼5 h after LPS application, we observed a net increase in the average number of spikes elicited in engaged cells and within each burst, but no changes neither in spike waveforms nor in burst rate. This effect was characterized by a slow, twofold exponential increase of the burst duration and the appearance of rarely occurring long burst events that were never seen during control recordings. These changes and the time-course of microglia-released proinflammatory cytokine, tumor necrosis factor-alpha (TNF-α), were blocked by pre-treatment with 50 nM minocycline, an established anti-inflammatory agent which was inactive when applied alone. Assay experiments also revealed that application of 60 pM exogenous TNF-α after 12–15 h, produced non-washable changes of neuronal excitability, completely different from those induced by LPS, suggesting that TNF-α release alone was not responsible for our observed findings. Our results indicate that the link between neuroinflammation and hyperexcitability can be unveiled by studying the long-term activity of in vitro neuronal/astrocyte/microglial networks.
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Affiliation(s)
- Francesca Gullo
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan Italy
| | - Alida Amadeo
- Department of Biomolecular Sciences and Biotechnology, University of Milan, Milan Italy
| | - Giulia Donvito
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan Italy
| | - Marzia Lecchi
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan Italy
| | - Barbara Costa
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan Italy
| | | | - Enzo Wanke
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Milan Italy
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245
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Schapansky J, Nardozzi JD, LaVoie MJ. The complex relationships between microglia, alpha-synuclein, and LRRK2 in Parkinson's disease. Neuroscience 2014; 302:74-88. [PMID: 25284317 DOI: 10.1016/j.neuroscience.2014.09.049] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 09/22/2014] [Accepted: 09/23/2014] [Indexed: 12/19/2022]
Abstract
The proteins alpha-synuclein (αSyn) and leucine rich repeat kinase 2 (LRRK2) are both key players in the pathogenesis of the neurodegenerative disorder Parkinson's disease (PD), but establishing a functional link between the two proteins has proven elusive. Research studies for these two proteins have traditionally and justifiably focused in neuronal cells, but recent studies indicate that each protein could play a greater pathological role elsewhere. αSyn is expressed at high levels within neurons, but they also secrete the protein into the extracellular milieu, where it can have broad ranging effects in the nervous system and relevance to disease etiology. Similarly, low neuronal LRRK2 expression and activity suggests that LRRK2-related functions could be more relevant in cells with higher expression, such as brain-resident microglia. Microglia are monocytic immune cells that protect neurons from noxious stimuli, including pathological αSyn species, and microglial activation is believed to contribute to neuroinflammation and neuronal death in PD. Interestingly, both αSyn and LRRK2 can be linked to microglial function. Secreted αSyn can directly activate microglia, and can be taken up by microglia for clearance, while LRRK2 has been implicated in the intrinsic regulation of microglial activation and of lysosomal degradation processes. Based on these observations, the present review will focus on how PD-associated mutations in LRRK2 could potentially alter microglial biology with respect to neuronally secreted αSyn, resulting in cell dysfunction and neurodegeneration.
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Affiliation(s)
- J Schapansky
- Center for Neurologic Diseases, Harvard Medical School, and Brigham and Women's Hospital, Boston, MA 02115, United States
| | - J D Nardozzi
- Center for Neurologic Diseases, Harvard Medical School, and Brigham and Women's Hospital, Boston, MA 02115, United States
| | - M J LaVoie
- Center for Neurologic Diseases, Harvard Medical School, and Brigham and Women's Hospital, Boston, MA 02115, United States.
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Sheridan GK, Wdowicz A, Pickering M, Watters O, Halley P, O'Sullivan NC, Mooney C, O'Connell DJ, O'Connor JJ, Murphy KJ. CX3CL1 is up-regulated in the rat hippocampus during memory-associated synaptic plasticity. Front Cell Neurosci 2014; 8:233. [PMID: 25161610 PMCID: PMC4130185 DOI: 10.3389/fncel.2014.00233] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 07/25/2014] [Indexed: 11/13/2022] Open
Abstract
Several cytokines and chemokines are now known to play normal physiological roles in the brain where they act as key regulators of communication between neurons, glia, and microglia. In particular, cytokines and chemokines can affect cardinal cellular and molecular processes of hippocampal-dependent long-term memory consolidation including synaptic plasticity, synaptic scaling and neurogenesis. The chemokine, CX3CL1 (fractalkine), has been shown to modulate synaptic transmission and long-term potentiation (LTP) in the CA1 pyramidal cell layer of the hippocampus. Here, we confirm widespread expression of CX3CL1 on mature neurons in the adult rat hippocampus. We report an up-regulation in CX3CL1 protein expression in the CA1, CA3 and dentate gyrus (DG) of the rat hippocampus 2 h after spatial learning in the water maze task. Moreover, the same temporal increase in CX3CL1 was evident following LTP-inducing theta-burst stimulation in the DG. At physiologically relevant concentrations, CX3CL1 inhibited LTP maintenance in the DG. This attenuation in dentate LTP was lost in the presence of GABAA receptor/chloride channel antagonism. CX3CL1 also had opposing actions on glutamate-mediated rise in intracellular calcium in hippocampal organotypic slice cultures in the presence and absence of GABAA receptor/chloride channel blockade. Using primary dissociated hippocampal cultures, we established that CX3CL1 reduces glutamate-mediated intracellular calcium rises in both neurons and glia in a dose dependent manner. In conclusion, CX3CL1 is up-regulated in the hippocampus during a brief temporal window following spatial learning the purpose of which may be to regulate glutamate-mediated neurotransmission tone. Our data supports a possible role for this chemokine in the protective plasticity process of synaptic scaling.
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Affiliation(s)
- Graham K Sheridan
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland ; Department of Physiology, Development and Neuroscience, University of Cambridge Cambridge, UK
| | - Anita Wdowicz
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Mark Pickering
- School of Medicine and Medical Science, Health Sciences Centre, University College Dublin Dublin, Ireland
| | - Orla Watters
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Paul Halley
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Niamh C O'Sullivan
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Claire Mooney
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - David J O'Connell
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - John J O'Connor
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Keith J Murphy
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
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247
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Neiva I, Malva JO, Valero J. Can we talk about microglia without neurons? A discussion of microglial cell autonomous properties in culture. Front Cell Neurosci 2014; 8:202. [PMID: 25104923 PMCID: PMC4109436 DOI: 10.3389/fncel.2014.00202] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 07/04/2014] [Indexed: 11/24/2022] Open
Affiliation(s)
- Ismael Neiva
- Neuroprotection and Neurogenesis in Brain Repair Group, Center for Neuroscience and Cell Biology, University of Coimbra Coimbra, Portugal
| | - João O Malva
- Neuroprotection and Neurogenesis in Brain Repair Group, Center for Neuroscience and Cell Biology, University of Coimbra Coimbra, Portugal ; Faculty of Medicine, Institute of Biomedical Imaging and Life Sciences, University of Coimbra Coimbra, Portugal
| | - Jorge Valero
- Neuroprotection and Neurogenesis in Brain Repair Group, Center for Neuroscience and Cell Biology, University of Coimbra Coimbra, Portugal ; Institute for Interdisciplinary Research, University of Coimbra Coimbra, Portugal
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248
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Cuenca N, Fernández-Sánchez L, Campello L, Maneu V, De la Villa P, Lax P, Pinilla I. Cellular responses following retinal injuries and therapeutic approaches for neurodegenerative diseases. Prog Retin Eye Res 2014; 43:17-75. [PMID: 25038518 DOI: 10.1016/j.preteyeres.2014.07.001] [Citation(s) in RCA: 296] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/03/2014] [Accepted: 07/07/2014] [Indexed: 01/17/2023]
Abstract
Retinal neurodegenerative diseases like age-related macular degeneration, glaucoma, diabetic retinopathy and retinitis pigmentosa each have a different etiology and pathogenesis. However, at the cellular and molecular level, the response to retinal injury is similar in all of them, and results in morphological and functional impairment of retinal cells. This retinal degeneration may be triggered by gene defects, increased intraocular pressure, high levels of blood glucose, other types of stress or aging, but they all frequently induce a set of cell signals that lead to well-established and similar morphological and functional changes, including controlled cell death and retinal remodeling. Interestingly, an inflammatory response, oxidative stress and activation of apoptotic pathways are common features in all these diseases. Furthermore, it is important to note the relevant role of glial cells, including astrocytes, Müller cells and microglia, because their response to injury is decisive for maintaining the health of the retina or its degeneration. Several therapeutic approaches have been developed to preserve retinal function or restore eyesight in pathological conditions. In this context, neuroprotective compounds, gene therapy, cell transplantation or artificial devices should be applied at the appropriate stage of retinal degeneration to obtain successful results. This review provides an overview of the common and distinctive features of retinal neurodegenerative diseases, including the molecular, anatomical and functional changes caused by the cellular response to damage, in order to establish appropriate treatments for these pathologies.
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Affiliation(s)
- Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain; Multidisciplinary Institute for Environmental Studies "Ramon Margalef", University of Alicante, Alicante, Spain.
| | - Laura Fernández-Sánchez
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Laura Campello
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Victoria Maneu
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Pedro De la Villa
- Department of Systems Biology, University of Alcalá, Alcalá de Henares, Spain
| | - Pedro Lax
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Isabel Pinilla
- Department of Ophthalmology, Lozano Blesa University Hospital, Aragon Institute of Health Sciences, Zaragoza, Spain
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249
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Parasite-derived neurotrophic factor/trans-sialidase of Trypanosoma cruzi links neurotrophic signaling to cardiac innate immune response. Infect Immun 2014; 82:3687-96. [PMID: 24935974 DOI: 10.1128/iai.02098-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Chagas' disease parasite Trypanosoma cruzi elicits a potent inflammatory response in acutely infected hearts that keeps parasitism in check and triggers cardiac abnormalities. A most-studied mechanism underlying innate immunity in T. cruzi infection is Toll-like receptor (TLR) activation by lipids and other parasite molecules. However, yet-to-be-identified pathways should exist. Here, we show that T. cruzi strongly upregulates monocyte chemoattractant protein 1 (MCP-1)/CCL2 and fractalkine (FKN)/CX3CL1 in cellular and mouse models of heart infection. Mechanistically, upregulation of MCP-1 and FKN stems from the interaction of parasite-derived neurotrophic factor (PDNF)/trans-sialidase with neurotrophic receptors TrkA and TrkC, as assessed by pharmacological inhibition, neutralizing antibodies, and gene silencing studies. Administration of a single dose of intravenous PDNF to naive mice results in a dose-dependent increase in MCP-1 and FKN in the heart and liver with pulse-like kinetics that peak at 3 h postinjection. Intravenous PDNF also augments MCP-1 and FKN in TLR signaling-deficient MyD88-knockout mice, underscoring the MyD88-independent action of PDNF. Although single PDNF injections do not increase MCP-1 and FKN receptors, multiple PDNF injections at short intervals up the levels of receptor transcripts in the heart and liver, suggesting that sustained PDNF triggers cell recruitment at infection sites. Thus, given that MCP-1 and FKN are chemokines essential to the recruitment of immune cells to combat inflammation triggers and to enhance tissue repair, our findings uncover a new mechanism in innate immunity against T. cruzi infection mediated by Trk signaling akin to an endogenous inflammatory and fibrotic pathway resulting from cardiomyocyte-TrkA recognition by matricellular connective tissue growth factor (CTGF/CCN2).
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250
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Williams JL, Holman DW, Klein RS. Chemokines in the balance: maintenance of homeostasis and protection at CNS barriers. Front Cell Neurosci 2014; 8:154. [PMID: 24920943 PMCID: PMC4036130 DOI: 10.3389/fncel.2014.00154] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Accepted: 05/15/2014] [Indexed: 12/15/2022] Open
Abstract
In the adult central nervous system (CNS), chemokines and their receptors are involved in developmental, physiological and pathological processes. Although most lines of investigation focus on their ability to induce the migration of cells, recent studies indicate that chemokines also promote cellular interactions and activate signaling pathways that maintain CNS homeostatic functions. Many homeostatic chemokines are expressed on the vasculature of the blood brain barrier (BBB) including CXCL12, CCL19, CCL20, and CCL21. While endothelial cell expression of these chemokines is known to regulate the entry of leukocytes into the CNS during immunosurveillance, new data indicate that CXCL12 is also involved in diverse cellular activities including adult neurogenesis and neuronal survival, having an opposing role to the homeostatic chemokine, CXCL14, which appears to regulate synaptic inputs to neural precursors. Neuronal expression of CX3CL1, yet another homeostatic chemokine that promotes neuronal survival and communication with microglia, is partly regulated by CXCL12. Regulation of CXCL12 is unique in that it may regulate its own expression levels via binding to its scavenger receptor CXCR7/ACKR3. In this review, we explore the diverse roles of these and other homeostatic chemokines expressed within the CNS, including the possible implications of their dysfunction as a cause of neurologic disease.
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Affiliation(s)
- Jessica L Williams
- Department of Internal Medicine, Washington University School of Medicine St. Louis, MO, USA
| | - David W Holman
- Infectious Diseases Division, Decision Resources Group Burlington, MA, USA
| | - Robyn S Klein
- Department of Internal Medicine, Washington University School of Medicine St. Louis, MO, USA ; Department of Pathology and Immunology, Washington University School of Medicine St. Louis, MO, USA ; Department of Anatomy and Neurobiology, Washington University School of Medicine St. Louis, MO, USA
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