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Zhang C, Shi G, Meng Q, Hu R, Li Y, Hu G, Wang K, Huang M. An approach based on a combination of toxicological experiments and in silico predictions to investigate the adverse outcome pathway (AOP) of paraquat neuro-immunotoxicity. JOURNAL OF HAZARDOUS MATERIALS 2024; 473:134607. [PMID: 38761765 DOI: 10.1016/j.jhazmat.2024.134607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/30/2024] [Accepted: 05/11/2024] [Indexed: 05/20/2024]
Abstract
Paraquat (PQ) exposure is strongly associated with neurotoxicity. However, research on the neurotoxicity mechanisms of PQ varies in terms of endpoints of toxic assessment, resulting in a great challenge to understand the early neurotoxic effects of PQ. In this study, we developed an adverse outcome pathway (AOP) to investigate PQ-induced neuro-immunotoxicity from an immunological perspective, combining of traditional toxicology methods and computer simulations. In vivo, PQ can microstructurally lead to an early synaptic loss in the brain mice, which is a large degree regarded as a main reason for cognitive impairment to mice behavior. Both in vitro and in vivo demonstrated synapse loss is caused by excessive activation of the complement C1q/C3-CD11b pathway, which mediates microglial phagocytosis dysfunction. Additionally, the interaction between PQ and C1q was validated by molecular simulation docking. Our findings extend the AOP framework related to PQ neurotoxicity from a neuro-immunotoxic perspective, highlighting C1q activation as the initiating event for PQ-induced neuro-immunotoxicity. In addition, downstream complement cascades induce abnormal microglial phagocytosis, resulting in reduced synaptic density and subsequent non-motor dysfunction. These findings deepen our understanding of neurotoxicity and provide a theoretical basis for ecological risk assessment of PQ.
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Affiliation(s)
- Chunhui Zhang
- School of Public Health, Ningxia Medical University, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, the Street of Shengli, Xingqing District, Yinchuan, Ningxia, China
| | - Ge Shi
- School of Public Health, Ningxia Medical University, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, the Street of Shengli, Xingqing District, Yinchuan, Ningxia, China
| | - Qi Meng
- School of Public Health, Ningxia Medical University, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, the Street of Shengli, Xingqing District, Yinchuan, Ningxia, China
| | - Rong Hu
- School of Public Health, Ningxia Medical University, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, the Street of Shengli, Xingqing District, Yinchuan, Ningxia, China
| | - Yang Li
- School of Public Health, Ningxia Medical University, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, the Street of Shengli, Xingqing District, Yinchuan, Ningxia, China
| | - Guiling Hu
- School of Public Health, Ningxia Medical University, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, the Street of Shengli, Xingqing District, Yinchuan, Ningxia, China
| | - Kaidong Wang
- School of Public Health, Ningxia Medical University, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, the Street of Shengli, Xingqing District, Yinchuan, Ningxia, China.
| | - Min Huang
- School of Public Health, Ningxia Medical University, China; Key Laboratory of Environmental Factors and Chronic Disease Control, No.1160, the Street of Shengli, Xingqing District, Yinchuan, Ningxia, China.
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Zhou LQ, Chu YH, Dong MH, Yang S, Chen M, Tang Y, Pang XW, You YF, Wu LJ, Wang W, Qin C, Tian DS. Ldl-stimulated microglial activation exacerbates ischemic white matter damage. Brain Behav Immun 2024; 119:416-430. [PMID: 38636563 DOI: 10.1016/j.bbi.2024.04.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 04/03/2024] [Accepted: 04/16/2024] [Indexed: 04/20/2024] Open
Abstract
The role of microglia in triggering the blood-brain barrier (BBB) impairment and white matter damage after chronic cerebral hypoperfusion is unclear. Here we demonstrated that the vessel-adjacent microglia were specifically activated by the leakage of plasma low-density lipoprotein (LDL), which led to BBB breakdown and ischemic demyelination. Interestingly, we found that LDL stimulation enhanced microglial phagocytosis, causing excessive engulfment of myelin debris and resulting in an overwhelming lipid burden in microglia. Surprisingly, these lipid-laden microglia exhibited a suppressed profile of inflammatory response and compromised pro-regenerative properties. Microglia-specific knockdown of LDLR or systematic medication lowering circulating LDL-C showed protective effects against ischemic demyelination. Overall, our findings demonstrated that LDL-stimulated vessel-adjacent microglia possess a disease-specific molecular signature, characterized by suppressed regenerative properties, which is associated with the propagation of demyelination during ischemic white matter damage.
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Affiliation(s)
- Luo-Qi Zhou
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yun-Hui Chu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ming-Hao Dong
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Sheng Yang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Man Chen
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yue Tang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiao-Wei Pang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yun-Fan You
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Chuan Qin
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Dai-Shi Tian
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan 430030, China; Key Laboratory of Vascular Aging, Ministry of Education, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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Sun Y, Zhang H, Liu R, Huang R, Zhang X, Zhou S, Wu L, Zhu B, Wu H. Pyrolae herba alleviates cognitive impairment via hippocampal TREM2 signaling modulating neuroinflammation and neurogenesis in lipopolysaccharide-treated mice. JOURNAL OF ETHNOPHARMACOLOGY 2024; 319:117214. [PMID: 37739108 DOI: 10.1016/j.jep.2023.117214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 09/17/2023] [Accepted: 09/20/2023] [Indexed: 09/24/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANC Pyrolae herba (PH), a kind of Chinese herb, has been identified to have an anti-inflammatory effect, while the potential for treating cognitive impairment (CI), as well as the underlying mechanisms, is unclear. Currently, the interaction between neuroinflammation and neural function play a critical role in pathophysiology of CI. AIM OF THE STUDY To elucidate therapeutic effect of PH for CI as well as its underlying mechanisms with LPS-treated mice model. METHODS AND MATERIALS In this study, male C57BL6/J mice received lipopolysaccharide (LPS) injection for 10 days to establish CI model and were administrated with PH for 14 days. We used piracetam as a positive control. Memory and spatial function was tested by Morris water maze (MWM). The level of inflammation-related cytokines (TNF-α, IL-1β, IL-10, IL-6) were determined by enzyme-linked immunosorbent assay (ELISA) in serum and western blot in hippocampus. Immunofluorescence (IF) was used to measure the levels of ionized calcium binding linker molecule 1 (IBA-1), glial fibrillary acidic protein (GFAP), BrdU, Ki67 and doublecortin (DCX) in hippocampus. The mRNA sequencing was used to screen the potential target of PH with therapeutic CI. Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the gene alteration of triggering receptor expressed on myeloid cells 2 (TREM2) in hippocampus. We used western blot to determine protein expressions of TREM2 and its related signaling, as well as synaptic proteins in hippocampus. RESULTS The results revealed that LPS contributed to CI, and PH or piracetam treatment significantly ameliorated CI in MWM test. LPS contributed to increasing expressions of TNF-α and IL-1β in serum and hippocampus, which both reversed by PH or piracetam. PH or piracetam could inhibit the activation of glial cells including microglia and astrocyte in the hippocampus in LPS-induced CI model. The mRNA sequencing and RT-PCR results showed that LPS significantly increased the gene expression of TREM2, which was reversed by PH. The alteration of TREM2 expression was the most significant among the 10 genes (TREM2, Slc24a2, Ptch2, Gck, Il1rapl1, Cadps2, Btbd11, Secisbp2l, Tenm3 and Prepl) in hippocampus. Protein results showed that LPS upregulated the expressions of TREM2 and its related proteins including DAP12, spleen tyrosine kinase (SYK) phosphorylation and ADAM 10, which were all reversed by PH or piracetam in hippocampus. Furthermore, LPS was capable of reducing the expression of BrdU and DCX co-labeled positive cells in hippocampal dentate gyrus (DG), which was reversed only by PH. Moreover, PH or piracetam treatment significantly increased the expression of Ki67 and DCX co-labeled positive cells in hippocampal DG. The expression of synapsin1 was obviously decreased by LPS and was significantly reversed by PH or piracetam. CONCLUSIONS PH could alleviate CI by suppressing the secretion of pro-inflammatory cytokines and mitigating astrocyte activity by restraining microglia's activation in hippocampus, further facilitating neurogenesis and proliferation, thereby enhancing pre-synaptic protein. This study highlighted on the clinical application of PH, which might promote the use of phytomedicine in CI patients.
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Affiliation(s)
- Yan Sun
- Key Laboratory of Integrative Biomedicine for Brain Diseases, School of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, PR China; National Famous Chinese Medicine Expert Inheritance Studio (Meng Jingchun), Nanjing University of Chinese Medicine, School of Chinese Medicine, Nanjing, 210023, PR China
| | - Hailou Zhang
- Interdisciplinary Institute for Personalized Medicine in Brain Disorders, Jinan University, Guangzhou, 510632, PR China
| | - Ruiyu Liu
- Key Laboratory of Integrative Biomedicine for Brain Diseases, School of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, PR China; National Famous Chinese Medicine Expert Inheritance Studio (Meng Jingchun), Nanjing University of Chinese Medicine, School of Chinese Medicine, Nanjing, 210023, PR China; Interdisciplinary Institute for Personalized Medicine in Brain Disorders, Jinan University, Guangzhou, 510632, PR China
| | - Rumin Huang
- Key Laboratory of Integrative Biomedicine for Brain Diseases, School of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, PR China; National Famous Chinese Medicine Expert Inheritance Studio (Meng Jingchun), Nanjing University of Chinese Medicine, School of Chinese Medicine, Nanjing, 210023, PR China
| | - Xiangrui Zhang
- Key Laboratory of Integrative Biomedicine for Brain Diseases, School of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, PR China; National Famous Chinese Medicine Expert Inheritance Studio (Meng Jingchun), Nanjing University of Chinese Medicine, School of Chinese Medicine, Nanjing, 210023, PR China
| | - Shihan Zhou
- Key Laboratory of Integrative Biomedicine for Brain Diseases, School of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, PR China; National Famous Chinese Medicine Expert Inheritance Studio (Meng Jingchun), Nanjing University of Chinese Medicine, School of Chinese Medicine, Nanjing, 210023, PR China
| | - Lei Wu
- Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing, 210029, PR China
| | - Boran Zhu
- Key Laboratory of Integrative Biomedicine for Brain Diseases, School of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, PR China; National Famous Chinese Medicine Expert Inheritance Studio (Meng Jingchun), Nanjing University of Chinese Medicine, School of Chinese Medicine, Nanjing, 210023, PR China.
| | - Haoxin Wu
- Key Laboratory of Integrative Biomedicine for Brain Diseases, School of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, PR China; National Famous Chinese Medicine Expert Inheritance Studio (Meng Jingchun), Nanjing University of Chinese Medicine, School of Chinese Medicine, Nanjing, 210023, PR China.
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Hou P, Zielonka M, Serneels L, Martinez-Muriana A, Fattorelli N, Wolfs L, Poovathingal S, T'Syen D, Balusu S, Theys T, Fiers M, Mancuso R, Howden AJM, De Strooper B. The γ-secretase substrate proteome and its role in cell signaling regulation. Mol Cell 2023; 83:4106-4122.e10. [PMID: 37977120 DOI: 10.1016/j.molcel.2023.10.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 06/22/2023] [Accepted: 10/20/2023] [Indexed: 11/19/2023]
Abstract
γ-Secretases mediate the regulated intramembrane proteolysis (RIP) of more than 150 integral membrane proteins. We developed an unbiased γ-secretase substrate identification (G-SECSI) method to study to what extent these proteins are processed in parallel. We demonstrate here parallel processing of at least 85 membrane proteins in human microglia in steady-state cell culture conditions. Pharmacological inhibition of γ-secretase caused substantial changes of human microglial transcriptomes, including the expression of genes related to the disease-associated microglia (DAM) response described in Alzheimer disease (AD). While the overall effects of γ-secretase deficiency on transcriptomic cell states remained limited in control conditions, exposure of mouse microglia to AD-inducing amyloid plaques strongly blocked their capacity to mount this putatively protective DAM cell state. We conclude that γ-secretase serves as a critical signaling hub integrating the effects of multiple extracellular stimuli into the overall transcriptome of the cell.
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Affiliation(s)
- Pengfei Hou
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Magdalena Zielonka
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Lutgarde Serneels
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Anna Martinez-Muriana
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Nicola Fattorelli
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Leen Wolfs
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Suresh Poovathingal
- Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium; Single Cell & Microfluidics Expertise Unit, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium
| | - Dries T'Syen
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Sriram Balusu
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Tom Theys
- Department of Neurosciences, Research Group Experimental Neurosurgery and Neuroanatomy, KU Leuven, Leuven 3000, Belgium
| | - Mark Fiers
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium; Center for Human Genetics, KU Leuven, Leuven 3000, Belgium; Dementia Research Institute, Institute of Neurology, University College London, London WC1E 6BT, UK
| | - Renzo Mancuso
- Microglia and Inflammation in Neurological Disorders (MIND) Lab, VIB Center for Molecular Neurology, VIB, Antwerp 2610, Belgium; Department of Biomedical Sciences, University of Antwerp, Antwerp 2610, Belgium
| | - Andrew J M Howden
- Division of Cell Signaling and Immunology, School of Life Sciences, University of Dundee, Dundee DD1 4HN, UK
| | - Bart De Strooper
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven 3000, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium; Center for Human Genetics, KU Leuven, Leuven 3000, Belgium; Dementia Research Institute, Institute of Neurology, University College London, London WC1E 6BT, UK.
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5
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Kiss T, Mir Y, Stefancsik G, Ganbat G, Askarova A, Monostori E, Dulka K, Szebeni GJ, Nyúl-Tóth Á, Csiszár A, Legradi A. Galectin-1 as a marker for microglia activation in the aging brain. Brain Res 2023; 1818:148517. [PMID: 37557976 DOI: 10.1016/j.brainres.2023.148517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/21/2023] [Accepted: 08/02/2023] [Indexed: 08/11/2023]
Abstract
Microglia cells, the immune cells residing in the brain, express immune regulatory molecules that have a central role in the manifestation of age-related brain characteristics. Our hypothesis suggests that galectin-1, an anti-inflammatory member of the beta-galactoside-binding lectin family, regulates microglia and neuroinflammation in the aging brain. Through our in-silico analysis, we discovered a subcluster of microglia in the aged mouse brain that exhibited increased expression of galectin-1 mRNA. In our Western blotting experiments, we observed a decrease in galectin-1 protein content in our rat primary cortical cultures over time. Additionally, we found that the presence of lipopolysaccharide, an immune activator, significantly increased the expression of galectin-1 protein in microglial cells. Utilizing flow cytometry, we determined that a portion of the galectin-1 protein was localized on the surface of the microglial cells. As cultivation time increased, we observed a decrease in the expression of activation-coupled molecules in microglial cells, indicating cellular exhaustion. In our mixed rat primary cortical cell cultures, we noted a transition of amoeboid microglial cells labeled with OX42(CD11b/c) to a ramified, branched phenotype during extended cultivation, accompanied by a complete disappearance of galectin-1 expression. By analyzing the transcriptome of a distinct microglial subpopulation in an animal model of aging, we established a correlation between chronological aging and galectin-1 expression. Furthermore, our in vitro study demonstrated that galectin-1 expression is associated with the functional activation state of microglial cells exhibiting specific amoeboid morphological characteristics. Based on our findings, we identify galectin-1 as a marker for microglia activation in the context of aging.
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Affiliation(s)
- Tamas Kiss
- Pediatric Center, Semmelweis University, Budapest, Hungary; Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
| | - Yaqub Mir
- Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary; Department of Computational Sciences, Wigner Research Centre for Physics, Budapest, Hungary; Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Gergely Stefancsik
- Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Gantulga Ganbat
- Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Aruzhan Askarova
- Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Eva Monostori
- Lymphocyte Signal Transduction Laboratory, Institute of Genetics, Biological Research Centre, Szeged, Hungary
| | - Karolina Dulka
- Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary.
| | - Gabor J Szebeni
- Laboratory of Functional Genomics, Biological Research Centre, ELKH, Szeged, Hungary; Department of Physiology, Anatomy and Neuroscience, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary.
| | - Ádám Nyúl-Tóth
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Departments of Public Health and Translational Medicine, Semmelweis University, Budapest, Hungary; Institute of Biophysics, Biological Research Centre, ELKH, Szeged, Hungary.
| | - Anna Csiszár
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary; Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Departments of Public Health and Translational Medicine, Semmelweis University, Budapest, Hungary; The Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
| | - Adam Legradi
- Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary.
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Samuels JD, Lukens JR, Price RJ. Emerging roles for ITAM and ITIM receptor signaling in microglial biology and Alzheimer's disease-related amyloidosis. J Neurochem 2023. [PMID: 37822118 DOI: 10.1111/jnc.15981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/11/2023] [Accepted: 09/21/2023] [Indexed: 10/13/2023]
Abstract
Microglia are critical responders to amyloid beta (Aβ) plaques in Alzheimer's disease (AD). Therefore, the therapeutic targeting of microglia in AD is of high clinical interest. While previous investigation has focused on the innate immune receptors governing microglial functions in response to Aβ plaques, how microglial innate immune responses are regulated is not well understood. Interestingly, many of these microglial innate immune receptors contain unique cytoplasmic motifs, termed immunoreceptor tyrosine-based activating and inhibitory motifs (ITAM/ITIM), that are commonly known to regulate immune activation and inhibition in the periphery. In this review, we summarize the diverse functions employed by microglia in response to Aβ plaques and also discuss the innate immune receptors and intracellular signaling players that guide these functions. Specifically, we focus on the role of ITAM and ITIM signaling cascades in regulating microglia innate immune responses. A better understanding of how microglial innate immune responses are regulated in AD may provide novel therapeutic avenues to tune the microglial innate immune response in AD pathology.
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Affiliation(s)
- Joshua D Samuels
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia (UVA), Charlottesville, Virginia, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
| | - John R Lukens
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia (UVA), Charlottesville, Virginia, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA
| | - Richard J Price
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA
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7
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Miao J, Ma H, Yang Y, Liao Y, Lin C, Zheng J, Yu M, Lan J. Microglia in Alzheimer's disease: pathogenesis, mechanisms, and therapeutic potentials. Front Aging Neurosci 2023; 15:1201982. [PMID: 37396657 PMCID: PMC10309009 DOI: 10.3389/fnagi.2023.1201982] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 05/30/2023] [Indexed: 07/04/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by protein aggregation in the brain. Recent studies have revealed the critical role of microglia in AD pathogenesis. This review provides a comprehensive summary of the current understanding of microglial involvement in AD, focusing on genetic determinants, phenotypic state, phagocytic capacity, neuroinflammatory response, and impact on synaptic plasticity and neuronal regulation. Furthermore, recent developments in drug discovery targeting microglia in AD are reviewed, highlighting potential avenues for therapeutic intervention. This review emphasizes the essential role of microglia in AD and provides insights into potential treatments.
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Affiliation(s)
- Jifei Miao
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Haixia Ma
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Guangzhou University of Chinese Medicine, Shenzhen, China
| | - Yang Yang
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Guangzhou University of Chinese Medicine, Shenzhen, China
| | - Yuanpin Liao
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Guangzhou University of Chinese Medicine, Shenzhen, China
| | - Cui Lin
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Juanxia Zheng
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Muli Yu
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Jiao Lan
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
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8
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Lyu S, Lan Z, Li C. The triggering receptor expressed on myeloid cells 2-apolipoprotein E signaling pathway in diseases. Chin Med J (Engl) 2023; 136:1291-1299. [PMID: 37130227 PMCID: PMC10309513 DOI: 10.1097/cm9.0000000000002167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Indexed: 05/04/2023] Open
Abstract
ABSTRACT Triggering receptor expressed on myeloid cells 2 (TREM2) is a membrane receptor on myeloid cells and plays an important role in the body's immune defense. Recently, TREM2 has received extensive attention from researchers, and its activity has been found in Alzheimer's disease, neuroinflammation, and traumatic brain injury. The appearance of TREM2 is usually accompanied by changes in apolipoprotein E (ApoE), and there has been a lot of research into their structure, as well as the interaction mode and signal pathways involved in them. As two molecules with broad and important roles in the human body, understanding their correlation may provide therapeutic targets for certain diseases. In this article, we reviewed several diseases in which TREM2 and ApoE are synergistically involved in the development. We further discussed the positive or negative effects of the TREM2-ApoE pathway on nervous system immunity and inflammation.
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Affiliation(s)
- Shukai Lyu
- Department of General Practice, The Fourth Affiliated Hospital, School of Medicine, Zhejiang University, Yiwu, Zhejiang 322000, China
| | - Zhuoqing Lan
- Department of General Practice, The Fourth Affiliated Hospital, School of Medicine, Zhejiang University, Yiwu, Zhejiang 322000, China
| | - Caixia Li
- Department of General Practice, The Fourth Affiliated Hospital, School of Medicine, Zhejiang University, Yiwu, Zhejiang 322000, China
- The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, China
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Muscat SM, Butler MJ, Mackey-Alfonso SE, Barrientos RM. Young adult and aged female rats are vulnerable to amygdala-dependent, but not hippocampus-dependent, memory impairment following short-term high-fat diet. Brain Res Bull 2023; 195:145-156. [PMID: 36870621 PMCID: PMC10257807 DOI: 10.1016/j.brainresbull.2023.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/18/2023] [Accepted: 03/01/2023] [Indexed: 03/06/2023]
Abstract
Global populations are increasingly consuming diets high in saturated fats and refined carbohydrates, and such diets have been well-associated with heightened inflammation and neurological dysfunction. Notably, older individuals are particularly vulnerable to the impact of unhealthy diet on cognition, even after a single meal, and pre-clinical rodent studies have demonstrated that short-term consumption of high-fat diet (HFD) induces marked increases in neuroinflammation and cognitive impairment. Unfortunately though, to date, most studies on the topic of nutrition and cognition, especially in aging, have been performed only in male rodents. This is especially concerning given that older females are more vulnerable to develop certain memory deficits and/or severe memory-related pathologies than males. Thus, the aim of the present study was to determine the extent to which short-term HFD consumption impacts memory function and neuroinflammation in female rats. Young adult (3 months) and aged (20-22 months) female rats were fed HFD for 3 days. Using contextual fear conditioning, we found that HFD had no effect on long-term contextual memory (hippocampus-dependent) at either age, but impaired long-term auditory-cued memory (amygdala-dependent) regardless of age. Gene expression of Il-1β was markedly dysregulated in the amygdala, but not hippocampus, of both young and aged rats after 3 days of HFD. Interestingly, modulation of IL-1 signaling via central administration of the IL-1 receptor antagonist (which we have previously demonstrated to be protective in males) had no impact on memory function following the HFD in females. Investigation of the memory-associated gene Pacap and its receptor Pac1r revealed differential effects of HFD on their expression in the hippocampus and amygdala. Specifically, HFD induced increased expression of Pacap and Pac1r in the hippocampus, whereas decreased Pacap was observed in the amygdala. Collectively, these data suggest that both young adult and aged female rats are vulnerable to amygdala-dependent (but not hippocampus-dependent) memory impairments following short-term HFD consumption, and identify potential mechanisms related to IL-1β and PACAP signaling in these differential effects. Notably, these findings are strikingly different than those previously reported in male rats using the same diet regimen and behavioral paradigms, and highlight the importance of examining potential sex differences in the context of neuroimmune-associated cognitive dysfunction.
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Affiliation(s)
- Stephanie M Muscat
- Institute for Behavioral Medicine Research, The Ohio State University, Columbus, OH, USA; Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH, USA
| | - Michael J Butler
- Institute for Behavioral Medicine Research, The Ohio State University, Columbus, OH, USA
| | - Sabrina E Mackey-Alfonso
- Institute for Behavioral Medicine Research, The Ohio State University, Columbus, OH, USA; Medical Scientist Training Program, The Ohio State University, Columbus, OH, USA
| | - Ruth M Barrientos
- Institute for Behavioral Medicine Research, The Ohio State University, Columbus, OH, USA; Department of Psychiatry and Behavioral Health, The Ohio State University, Columbus, OH, USA; Department of Neuroscience, The Ohio State University, Columbus, OH, USA; Chronic Brain Injury Program, The Ohio State University, Columbus, OH, USA.
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Biphenyl-based small molecule inhibitors: Novel cancer immunotherapeutic agents targeting PD-1/PD-L1 interaction. Bioorg Med Chem 2022; 73:117001. [PMID: 36126447 DOI: 10.1016/j.bmc.2022.117001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 08/25/2022] [Accepted: 09/03/2022] [Indexed: 11/23/2022]
Abstract
The immune checkpoint proteins are those key to the body's immunity which can either boost the immune system to protect the body from pathogens; or suppress the body's immunity system for the goal of self-tolerance. Cancer cells have evolved some mechanisms to boost the immuno-inhibitory checkpoints to bypass the immune system of the body. The binding of Programmed Cell Death-1 (PD-1) protein with its ligand Programmed Cell Death Ligand-1 (PD-L1) promotes this kind of immune-inhibitory signal. The discovery of immune checkpoint inhibitors was started in the early 21st century; with some success through monoclonal antibodies, peptides, and small molecules. Being the most reliable and safest way to target immune checkpoints, the scientific community is exploring possibilities to develop small molecule inhibitors. Among the different scaffolds of the small molecule, the most exposed and researched core molecule is Biphenyl-based scaffolds. We have described all of the possible biphenyl-based small molecules in this article, as well as their interactions with various amino acids in the binding cavity. The link between the in silico, in vitro, and in vivo activities of the PD-1/PD-L1 inhibitors are well connected. The Tyr56, Met115, Ala121, and Asp122 were detected as the crucial amino acids of the PD-1/PD-L1 inhibition. Additionally, a detailed binding pocket analysis of the PD-L1 receptor was carried out, where it was observed and confirmed that the binding pocket is tunnel-shaped and hydrophobic in nature. Finally, the structure-activity relationship of the biphenyl-based small molecule inhibitors was developed based on their activity and the binding interactions.
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11
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Carvalho K, Schartz ND, Balderrama-Gutierrez G, Liang HY, Chu SH, Selvan P, Gomez-Arboledas A, Petrisko TJ, Fonseca MI, Mortazavi A, Tenner AJ. Modulation of C5a-C5aR1 signaling alters the dynamics of AD progression. J Neuroinflammation 2022; 19:178. [PMID: 35820938 PMCID: PMC9277945 DOI: 10.1186/s12974-022-02539-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 06/23/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The complement system is part of the innate immune system that clears pathogens and cellular debris. In the healthy brain, complement influences neurodevelopment and neurogenesis, synaptic pruning, clearance of neuronal blebs, recruitment of phagocytes, and protects from pathogens. However, excessive downstream complement activation that leads to generation of C5a, and C5a engagement with its receptor C5aR1, instigates a feed-forward loop of inflammation, injury, and neuronal death, making C5aR1 a potential therapeutic target for neuroinflammatory disorders. C5aR1 ablation in the Arctic (Arc) model of Alzheimer's disease protects against cognitive decline and neuronal injury without altering amyloid plaque accumulation. METHODS To elucidate the effects of C5a-C5aR1 signaling on AD pathology, we crossed Arc mice with a C5a-overexpressing mouse (ArcC5a+) and tested hippocampal memory. RNA-seq was performed on hippocampus and cortex from Arc, ArcC5aR1KO, and ArcC5a+ mice at 2.7-10 months and age-matched controls to assess mechanisms involved in each system. Immunohistochemistry was used to probe for protein markers of microglia and astrocytes activation states. RESULTS ArcC5a+ mice had accelerated cognitive decline compared to Arc. Deletion of C5ar1 delayed or prevented the expression of some, but not all, AD-associated genes in the hippocampus and a subset of pan-reactive and A1 reactive astrocyte genes, indicating a separation between genes induced by amyloid plaques alone and those influenced by C5a-C5aR1 signaling. Biological processes associated with AD and AD mouse models, including inflammatory signaling, microglial cell activation, and astrocyte migration, were delayed in the ArcC5aR1KO hippocampus. Interestingly, C5a overexpression also delayed the increase of some AD-, complement-, and astrocyte-associated genes, suggesting the possible involvement of neuroprotective C5aR2. However, these pathways were enhanced in older ArcC5a+ mice compared to Arc. Immunohistochemistry confirmed that C5a-C5aR1 modulation in Arc mice delayed the increase in CD11c-positive microglia, while not affecting other pan-reactive microglial or astrocyte markers. CONCLUSION C5a-C5aR1 signaling in AD largely exerts its effects by enhancing microglial activation pathways that accelerate disease progression. While C5a may have neuroprotective effects via C5aR2, engagement of C5a with C5aR1 is detrimental in AD models. These data support specific pharmacological inhibition of C5aR1 as a potential therapeutic strategy to treat AD.
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Affiliation(s)
- Klebea Carvalho
- Department of Developmental & Cell Biology, University of California, Irvine, Irvine, CA 92697 USA
| | - Nicole D. Schartz
- Department of Molecular Biology & Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900 USA
| | | | - Heidi Y. Liang
- Department of Developmental & Cell Biology, University of California, Irvine, Irvine, CA 92697 USA
| | - Shu-Hui Chu
- Department of Molecular Biology & Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900 USA
| | - Purnika Selvan
- Department of Molecular Biology & Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900 USA
| | - Angela Gomez-Arboledas
- Department of Molecular Biology & Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900 USA
| | - Tiffany J. Petrisko
- Department of Molecular Biology & Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900 USA
| | - Maria I. Fonseca
- Department of Molecular Biology & Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900 USA
| | - Ali Mortazavi
- Department of Developmental & Cell Biology, University of California, Irvine, Irvine, CA 92697 USA
| | - Andrea J. Tenner
- Department of Molecular Biology & Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900 USA
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA USA
- Department of Pathology and Laboratory Medicine, University of California, Irvine, School of Medicine, Irvine, CA USA
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Han X, Han J, Wang N, Ji G, Guo R, Li J, Wu H, Ma S, Fang P, Song X. Identification of Auxiliary Biomarkers and Description of the Immune Microenvironmental Characteristics in Duchenne Muscular Dystrophy by Bioinformatical Analysis and Experiment. Front Neurosci 2022; 16:891670. [PMID: 35720684 PMCID: PMC9204148 DOI: 10.3389/fnins.2022.891670] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 05/04/2022] [Indexed: 11/13/2022] Open
Abstract
Background Duchenne muscular dystrophy (DMD) is a genetic muscle disorder characterized by progressive muscle wasting associated with persistent inflammation. In this study, we aimed to identify auxiliary biomarkers and further characterize the immune microenvironment in DMD. Methods Differentially expressed genes (DEGs) were identified between DMD and normal muscle tissues based on Gene Expression Omnibus (GEO) datasets. Bioinformatical analysis was used to screen and identify potential diagnostic signatures of DMD which were further validated by real-time quantitative reverse transcription PCR (RT-qPCR). We also performed single-sample gene-set enrichment analysis (ssGSEA) to characterize the proportion of tissue-infiltrating immune cells to determine the inflammatory state of DMD. Results In total, 182 downregulated genes and 263 upregulated genes were identified in DMD. C3, SPP1, TMSB10, TYROBP were regarded as adjunct biomarkers and successfully validated by RT-qPCR. The infiltration of macrophages, CD4+, and CD8+ T cells was significantly higher (p < 0.05) in DMD compared with normal muscle tissues, while the infiltration of activated B cells, CD56dim natural killer cells, and type 17 T helper (Th17) cells was lower. In addition, the four biomarkers (C3, SPP1, TMSB10, TYROBP) were strongly associated with immune cells and immune-related pathways in DMD muscle tissues. Conclusion Analyses demonstrated C3, SPP1, TMSB10, and TYROBP may serve as biomarkers and enhance our understanding of immune responses in DMD. The infiltration of immune cells into the muscle microenvironment might exert a critical impact on the development and occurrence of DMD.
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Affiliation(s)
- Xu Han
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
- Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - Jingzhe Han
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
- Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - Ning Wang
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
- Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - Guang Ji
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
- Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - Ruoyi Guo
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
- Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - Jing Li
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
- Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - Hongran Wu
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
- Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - Shaojuan Ma
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
- Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - Pingping Fang
- Department of Neurology, Handan Central Hospital, Handan, China
| | - Xueqin Song
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
- Neurological Laboratory of Hebei Province, Shijiazhuang, China
- *Correspondence: Xueqin Song,
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Chronic IL-10 overproduction disrupts microglia-neuron dialogue similar to aging, resulting in impaired hippocampal neurogenesis and spatial memory. Brain Behav Immun 2022; 101:231-245. [PMID: 34990747 DOI: 10.1016/j.bbi.2021.12.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 12/24/2021] [Accepted: 12/29/2021] [Indexed: 11/21/2022] Open
Abstract
The subgranular zone of the dentate gyrus is an adult neurogenic niche where new neurons are continuously generated. A dramatic hippocampal neurogenesis decline occurs with increasing age, contributing to cognitive deficits. The process of neurogenesis is intimately regulated by the microenvironment, with inflammation being considered a strong negative factor for this process. Thus, we hypothesize that the reduction of new neurons in the aged brain could be attributed to the age-related microenvironmental changes towards a pro-inflammatory status. In this work, we evaluated whether an anti-inflammatory microenvironment could counteract the negative effect of age on promoting new hippocampal neurons. Surprisingly, our results show that transgenic animals chronically overexpressing IL-10 by astrocytes present a decreased hippocampal neurogenesis in adulthood. This results from an impairment in the survival of neural newborn cells without differences in cell proliferation. In parallel, hippocampal-dependent spatial learning and memory processes were affected by IL-10 overproduction as assessed by the Morris water maze test. Microglial cells, which are key players in the neurogenesis process, presented a different phenotype in transgenic animals characterized by high activation together with alterations in receptors involved in neuronal communication, such as CD200R and CX3CR1. Interestingly, the changes described in adult transgenic animals were similar to those observed by the effect of normal aging. Thus, our data suggest that chronic IL-10 overproduction mimics the physiological age-related disruption of the microglia-neuron dialogue, resulting in hippocampal neurogenesis decrease and spatial memory impairment.
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14
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Zhang SS, Zhu L, Peng Y, Zhang L, Chao FL, Jiang L, Xiao Q, Liang X, Tang J, Yang H, He Q, Guo YJ, Zhou CN, Tang Y. Long-term running exercise improves cognitive function and promotes microglial glucose metabolism and morphological plasticity in the hippocampus of APP/PS1 mice. J Neuroinflammation 2022; 19:34. [PMID: 35123512 PMCID: PMC8817568 DOI: 10.1186/s12974-022-02401-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 01/24/2022] [Indexed: 02/06/2023] Open
Abstract
Background The role of physical exercise in the prevention of Alzheimer’s disease (AD) has been widely studied. Microglia play an important role in AD. Triggering receptor expressed in myeloid cells 2 (TREM2) is expressed on microglia and is known to mediate microglial metabolic activity and brain glucose metabolism. However, the relationship between brain glucose metabolism and microglial metabolic activity during running exercise in APP/PS1 mice remains unclear. Methods Ten-month-old male APP/PS1 mice and wild-type mice were randomly divided into sedentary groups or running groups (AD_Sed, WT_Sed, AD_Run and WT_Run, n = 20/group). Running mice had free access to a running wheel for 3 months. Behavioral tests, [18]F-FDG-PET and hippocampal RNA-Seq were performed. The expression levels of microglial glucose transporter (GLUT5), TREM2, soluble TREM2 (sTREM2), TYRO protein tyrosine kinase binding protein (TYROBP), secreted phosphoprotein 1 (SPP1), and phosphorylated spleen tyrosine kinase (p-SYK) were estimated by western blot or ELISA. Immunohistochemistry, stereological methods and immunofluorescence were used to investigate the morphology, proliferation and activity of microglia. Results Long-term voluntary running significantly improved cognitive function in APP/PS1 mice. Although there were few differentially expressed genes (DEGs), gene set enrichment analysis (GSEA) showed enriched glycometabolic pathways in APP/PS1 running mice. Running exercise increased FDG uptake in the hippocampus of APP/PS1 mice, as well as the protein expression of GLUT5, TREM2, SPP1 and p-SYK. The level of sTREM2 decreased in the plasma of APP/PS1 running mice. The number of microglia, the length and endpoints of microglial processes, and the ratio of GLUT5+/IBA1+ microglia were increased in the dentate gyrus (DG) of APP/PS1 running mice. Running exercise did not alter the number of 5-bromo-2′-deoxyuridine (BrdU)+/IBA1+ microglia but reduced the immunoactivity of CD68 in the hippocampus of APP/PS1 mice. Conclusions Running exercise inhibited TREM2 shedding and maintained TREM2 protein levels, which were accompanied by the promotion of brain glucose metabolism, microglial glucose metabolism and morphological plasticity in the hippocampus of AD mice. Microglia might be a structural target responsible for the benefits of running exercise in AD. Promoting microglial glucose metabolism and morphological plasticity modulated by TREM2 might be a novel strategy for AD treatment. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-022-02401-5.
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15
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Williams SE, Noel M, Lehoux S, Cetinbas M, Xavier RJ, Sadreyev RI, Scolnick EM, Smoller JW, Cummings RD, Mealer RG. Mammalian brain glycoproteins exhibit diminished glycan complexity compared to other tissues. Nat Commun 2022; 13:275. [PMID: 35022400 PMCID: PMC8755730 DOI: 10.1038/s41467-021-27781-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 12/08/2021] [Indexed: 01/14/2023] Open
Abstract
Glycosylation is essential to brain development and function, but prior studies have often been limited to a single analytical technique and excluded region- and sex-specific analyses. Here, using several methodologies, we analyze Asn-linked and Ser/Thr/Tyr-linked protein glycosylation between brain regions and sexes in mice. Brain N-glycans are less complex in sequence and variety compared to other tissues, consisting predominantly of high-mannose and fucosylated/bisected structures. Most brain O-glycans are unbranched, sialylated O-GalNAc and O-mannose structures. A consistent pattern is observed between regions, and sex differences are minimal compared to those in plasma. Brain glycans correlate with RNA expression of their synthetic enzymes, and analysis of glycosylation genes in humans show a global downregulation in the brain compared to other tissues. We hypothesize that this restricted repertoire of protein glycans arises from their tight regulation in the brain. These results provide a roadmap for future studies of glycosylation in neurodevelopment and disease.
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Affiliation(s)
- Sarah E Williams
- Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Maxence Noel
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Sylvain Lehoux
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Murat Cetinbas
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Ramnik J Xavier
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Ruslan I Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Edward M Scolnick
- Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- The Stanley Center for Psychiatric Research at Broad Institute of Harvard/MIT, Cambridge, MA, USA
| | - Jordan W Smoller
- Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- The Stanley Center for Psychiatric Research at Broad Institute of Harvard/MIT, Cambridge, MA, USA
- Center for Precision Psychiatry, Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Richard D Cummings
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Robert G Mealer
- Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
- The Stanley Center for Psychiatric Research at Broad Institute of Harvard/MIT, Cambridge, MA, USA.
- Center for Precision Psychiatry, Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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Bantle CM, Rocha SM, French CT, Phillips AT, Tran K, Olson KE, Bass TA, Aboellail T, Smeyne RJ, Tjalkens RB. Astrocyte inflammatory signaling mediates α-synuclein aggregation and dopaminergic neuronal loss following viral encephalitis. Exp Neurol 2021; 346:113845. [PMID: 34454938 PMCID: PMC9535678 DOI: 10.1016/j.expneurol.2021.113845] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 08/13/2021] [Accepted: 08/23/2021] [Indexed: 12/13/2022]
Abstract
Viral infection of the central nervous system (CNS) can cause lasting neurological decline in surviving patients and can present with symptoms resembling Parkinson's disease (PD). The mechanisms underlying postencephalitic parkinsonism remain unclear but are thought to involve increased innate inflammatory signaling in glial cells, resulting in persistent neuroinflammation. We therefore studied the role of glial cells in regulating neuropathology in postencephalitic parkinsonism by studying the involvement of astrocytes in loss of dopaminergic neurons and aggregation of α-synuclein protein following infection with western equine encephalitis virus (WEEV). Infections were conducted in both wildtype mice and in transgenic mice lacking NFκB inflammatory signaling in astrocytes. For 2 months following WEEV infection, we analyzed glial activation, neuronal loss and protein aggregation across multiple brain regions, including the substantia nigra pars compacta (SNpc). These data revealed that WEEV induces loss of SNpc dopaminergic neurons, persistent activation of microglia and astrocytes that precipitates widespread aggregation of α-synuclein in the brain of C57BL/6 mice. Microgliosis and macrophage infiltration occurred prior to activation of astrocytes and was followed by opsonization of ⍺-synuclein protein aggregates in the cortex, hippocampus and midbrain by the complement protein, C3. Astrocyte-specific NFκB knockout mice had reduced gliosis, α-synuclein aggregate formation and neuronal loss. These data suggest that astrocytes play a critical role in initiating PD-like pathology following encephalitic infection with WEEV through innate immune inflammatory pathways that damage dopaminergic neurons, possibly by hindering clearance of ⍺-synuclein aggregates. Inhibiting glial inflammatory responses could therefore represent a potential therapy strategy for viral parkinsonism.
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Affiliation(s)
- Collin M Bantle
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, United States of America
| | - Savannah M Rocha
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, United States of America
| | - C Tenley French
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, United States of America
| | - Aaron T Phillips
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, United States of America; Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, United States of America
| | - Kevin Tran
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, United States of America
| | - Kenneth E Olson
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, United States of America
| | - Todd A Bass
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, United States of America
| | - Tawfik Aboellail
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, United States of America
| | - Richard J Smeyne
- Jefferson Comprehensive Parkinson's Center, Vickie & Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, United States of America
| | - Ronald B Tjalkens
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, United States of America.
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Li Z, Wang Q, Hu H, Zheng W, Gao C. Research advances of biomaterials-based microenvironment-regulation therapies for repair and regeneration of spinal cord injury. Biomed Mater 2021; 16. [PMID: 34384071 DOI: 10.1088/1748-605x/ac1d3c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 08/12/2021] [Indexed: 12/15/2022]
Abstract
Traumatic spinal cord injury (SCI) usually results in restricted behaviour recovery and even life-changing paralysis, accompanied with numerous complications. Pathologically, the initial injuries trigger a series of secondary injuries, leading to an expansion of lesion site, a mass of neuron loss, and eventual failure of endogenous axon regeneration. As the advances rapidly spring up in regenerative medicine and tissue engineering biomaterials, regulation of these secondary injuries becomes possible, shedding a light on normal functional restoration. The successful tissue regeneration lies in proper regulation of the inflammatory microenvironment, including the inflammatory immune cells and inflammatory factors that lead to oxidative stress, inhibitory glial scar and neuroexcitatory toxicity. Specifically, the approaches based on microenvironment-regulating biomaterials have shown great promise in the repair and regeneration of SCI. In this review, the pathological inflammatory microenvironments of SCI are discussed, followed by the introduction of microenvironment-regulating biomaterials in terms of their impressive therapeutic effect in attenuation of secondary inflammation and promotion of axon regrowth. With the emphasis on regulating secondary events, the biomaterials for SCI treatment will become promising for clinical applications.
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Affiliation(s)
- Ziming Li
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, People's Republic of China
| | - Qiaoxuan Wang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, People's Republic of China
| | - Haijun Hu
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, People's Republic of China
| | - Weiwei Zheng
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, People's Republic of China
| | - Changyou Gao
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, People's Republic of China.,Dr Li Dak Sum and Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, Hangzhou, People's Republic of China
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Reporter cell assay for human CD33 validated by specific antibodies and human iPSC-derived microglia. Sci Rep 2021; 11:13462. [PMID: 34188106 PMCID: PMC8242067 DOI: 10.1038/s41598-021-92434-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 06/07/2021] [Indexed: 12/15/2022] Open
Abstract
CD33/Sialic acid-binding Ig-like lectin 3 (SIGLEC3) is an innate immune receptor expressed on myeloid cells and mediates inhibitory signaling via tyrosine phosphatases. Variants of CD33 are associated with Alzheimer’s disease (AD) suggesting that modulation of CD33 signaling might be beneficial in AD. Hence, there is an urgent need for reliable cellular CD33 reporter systems. Therefore, we generated a CD33 reporter cell line expressing a fusion protein consisting of the extracellular domain of either human full-length CD33 (CD33M) or the AD-protective variant CD33ΔE2 (D2-CD33/CD33m) linked to TYRO protein tyrosine kinase binding protein (TYROBP/DAP12) to investigate possible ligands and antibodies for modulation of CD33 signaling. Application of the CD33-specific antibodies P67.6 and 1c7/1 to the CD33M-DAP12 reporter cells resulted in increased phosphorylation of the kinase SYK, which is downstream of DAP12. CD33M-DAP12 but not CD33ΔE2-DAP12 expressing reporter cells showed increased intracellular calcium levels upon treatment with CD33 antibody P67.6 and partially for 1c7/1. Furthermore, stimulation of human induced pluripotent stem cell-derived microglia with the CD33 antibodies P67.6 or 1c7/1 directly counteracted the triggering receptor expressed on myeloid cells 2 (TREM2)-induced phosphorylation of SYK and decreased the phagocytic uptake of bacterial particles. Thus, the developed reporter system confirmed CD33 pathway activation by CD33 antibody clones P67.6 and 1c7/1. In addition, data showed that phosphorylation of SYK by TREM2 activation and phagocytosis of bacterial particles can be directly antagonized by CD33 signaling.
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Gheibihayat SM, Cabezas R, Nikiforov NG, Jamialahmadi T, Johnston TP, Sahebkar A. CD47 in the Brain and Neurodegeneration: An Update on the Role in Neuroinflammatory Pathways. Molecules 2021; 26:molecules26133943. [PMID: 34203368 PMCID: PMC8271744 DOI: 10.3390/molecules26133943] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 06/16/2021] [Accepted: 06/22/2021] [Indexed: 01/02/2023] Open
Abstract
CD47 is a receptor belonging to the immunoglobulin (Ig) superfamily and broadly expressed on cell membranes. Through interactions with ligands such as SIRPα, TSP-1, integrins, and SH2-domain bearing protein tyrosine phosphatase substrate-1 (SHPS-1), CD47 regulates numerous functions like cell adhesion, proliferation, apoptosis, migration, homeostasis, and the immune system. In this aspect, previous research has shown that CD47 modulates phagocytosis via macrophages, the transmigration of neutrophils, and the activation of T-cells, dendritic cells, and B-cells. Moreover, several studies have reported the increased expression of the CD47 receptor in a variety of diseases, including acute lymphoblastic leukemia (ALL), chronic myeloid leukemia, non-Hodgkin’s lymphoma (NHL), multiple myeloma (MM), bladder cancer, acute myeloid leukemia (AML), Gaucher disease, Multiple Sclerosis and stroke among others. The ubiquitous expression of the CD47 cell receptor on most resident cells of the CNS has previously been established through different methodologies. However, there is little information concerning its precise functions in the development of different neurodegenerative pathologies in the CNS. Consequently, further research pertaining to the specific functions and roles of CD47 and SIRP is required prior to its exploitation as a druggable approach for the targeting of various neurodegenerative diseases that affect the human population. The present review attempts to summarize the role of both CD47 and SIRP and their therapeutic potential in neurodegenerative disorders.
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Affiliation(s)
- Seyed Mohammad Gheibihayat
- Department of Genetics, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd 8916188635, Iran;
| | - Ricardo Cabezas
- Department of Physiology, School of Medicine, Universidad Antonio Nariño, Bogotá 111511, Colombia;
| | - Nikita G. Nikiforov
- Laboratory of Cellular and Molecular Pathology of Cardiovascular System, Institute of Human Morphology, Tsyurupa Street, 117418 Moscow, Russia;
- Laboratory of Medical Genetics, Institute of Experimental Cardiology, National Medical Research Center of Cardiology, 121552 Moscow, Russia
| | - Tannaz Jamialahmadi
- Department of Food Science and Technology, Quchan Branch, Islamic Azad University, Quchan 19395/1495, Iran;
- Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad 13944-91388, Iran
| | - Thomas P. Johnston
- Division of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO 64131, USA;
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad 13944-91388, Iran
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad 13944-91388, Iran
- School of Medicine, The University of Western Australia, Perth 6907, Australia
- School of Pharmacy, Mashhad University of Medical Sciences, Mashhad 13944-91388, Iran
- Correspondence: or
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Ermakov EA, Dmitrieva EM, Parshukova DA, Kazantseva DV, Vasilieva AR, Smirnova LP. Oxidative Stress-Related Mechanisms in Schizophrenia Pathogenesis and New Treatment Perspectives. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:8881770. [PMID: 33552387 PMCID: PMC7847339 DOI: 10.1155/2021/8881770] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 12/15/2020] [Accepted: 01/02/2021] [Indexed: 02/07/2023]
Abstract
Schizophrenia is recognized to be a highly heterogeneous disease at various levels, from genetics to clinical manifestations and treatment sensitivity. This heterogeneity is also reflected in the variety of oxidative stress-related mechanisms contributing to the phenotypic realization and manifestation of schizophrenia. At the molecular level, these mechanisms are supposed to include genetic causes that increase the susceptibility of individuals to oxidative stress and lead to gene expression dysregulation caused by abnormal regulation of redox-sensitive transcriptional factors, noncoding RNAs, and epigenetic mechanisms favored by environmental insults. These changes form the basis of the prooxidant state and lead to altered redox signaling related to glutathione deficiency and impaired expression and function of redox-sensitive transcriptional factors (Nrf2, NF-κB, FoxO, etc.). At the cellular level, these changes lead to mitochondrial dysfunction and metabolic abnormalities that contribute to aberrant neuronal development, abnormal myelination, neurotransmitter anomalies, and dysfunction of parvalbumin-positive interneurons. Immune dysfunction also contributes to redox imbalance. At the whole-organism level, all these mechanisms ultimately contribute to the manifestation and development of schizophrenia. In this review, we consider oxidative stress-related mechanisms and new treatment perspectives associated with the correction of redox imbalance in schizophrenia. We suggest that not only antioxidants but also redox-regulated transcription factor-targeting drugs (including Nrf2 and FoxO activators or NF-κB inhibitors) have great promise in schizophrenia. But it is necessary to develop the stratification criteria of schizophrenia patients based on oxidative stress-related markers for the administration of redox-correcting treatment.
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Affiliation(s)
- Evgeny A. Ermakov
- Laboratory of Repair Enzymes, Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Elena M. Dmitrieva
- Laboratory of Molecular Genetics and Biochemistry, Mental Health Research Institute, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk 634014, Russia
| | - Daria A. Parshukova
- Laboratory of Molecular Genetics and Biochemistry, Mental Health Research Institute, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk 634014, Russia
| | | | | | - Liudmila P. Smirnova
- Laboratory of Molecular Genetics and Biochemistry, Mental Health Research Institute, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk 634014, Russia
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Tajbakhsh A, Read M, Barreto GE, Ávila-Rodriguez M, Gheibi-Hayat SM, Sahebkar A. Apoptotic neurons and amyloid-beta clearance by phagocytosis in Alzheimer's disease: Pathological mechanisms and therapeutic outlooks. Eur J Pharmacol 2021; 895:173873. [PMID: 33460611 DOI: 10.1016/j.ejphar.2021.173873] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 01/06/2021] [Accepted: 01/11/2021] [Indexed: 12/13/2022]
Abstract
Neuronal survival and axonal renewal following central nervous system damage and in neurodegenerative illnesses, such as Alzheimer's disease (AD), can be enhanced by fast clearance of neuronal apoptotic debris, as well as the removal of amyloid beta (Aβ) by phagocytic cells through the process of efferocytosis. This process quickly inhibits the release of proinflammatory and antigenic autoimmune constituents, enhancing the formation of a microenvironment vital for neuronal survival and axonal regeneration. Therefore, the detrimental features associated with microglial phagocytosis uncoupling, such as the accumulation of apoptotic cells, inflammation and phagoptosis, could exacerbate the pathology in brain disease. Some mechanisms of efferocytosis could be targeted by several promising agents, such as curcumin, URMC-099 and Y-P30, which have emerged as potential treatments for AD. This review aims to investigate and update the current research regarding the signaling molecules and pathways involved in efferocytosis and how these could be targeted as a potential therapy in AD.
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Affiliation(s)
- Amir Tajbakhsh
- Department of Modern Sciences & Technologies, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Morgayn Read
- Department of Pharmacology, School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - George E Barreto
- Department of Biological Sciences, University of Limerick, Limerick, Ireland; Health Research Institute, University of Limerick, Limerick, Ireland
| | | | - Seyed Mohammad Gheibi-Hayat
- Department of Medical Biotechnology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Polish Mother's Memorial Hospital Research Institute (PMMHRI), Lodz, Poland.
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22
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Klaus C, Liao H, Allendorf DH, Brown GC, Neumann H. Sialylation acts as a checkpoint for innate immune responses in the central nervous system. Glia 2020; 69:1619-1636. [PMID: 33340149 DOI: 10.1002/glia.23945] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/23/2020] [Accepted: 11/26/2020] [Indexed: 12/28/2022]
Abstract
Sialic acids are monosaccharides that normally terminate the glycan chains of cell surface glyco-proteins and -lipids in mammals, and are highly enriched in the central nervous tissue. Sialic acids are conjugated to proteins and lipids (termed "sialylation") by specific sialyltransferases, and are removed ("desialylation") by neuraminidases. Cell surface sialic acids are sensed by complement factor H (FH) to inhibit complement activation or by sialic acid-binding immunoglobulin-like lectin (SIGLEC) receptors to inhibit microglial activation, phagocytosis, and oxidative burst. In contrast, desialylation of cells enables binding of the opsonins C1, calreticulin, galectin-3, and collectins, stimulating phagocytosis of such cells. Hypersialylation is used by bacteria and cancers as camouflage to escape immune recognition, while polysialylation of neurons protects synapses and neurogenesis. Insufficient lysosomal cleavage of sialylated molecules can lead to lysosomal accumulation of lipids and aggregated proteins, which if excessive may be expelled into the extracellular space. On the other hand, desialylation of immune receptors can activate them or trigger removal of proteins. Loss of inhibitory SIGLECs or FH triggers reduced clearance of aggregates, oxidative brain damage and complement-mediated retinal damage. Thus, cell surface sialylation recognized by FH, SIGLEC, and other immune-related receptors acts as a major checkpoint inhibitor of innate immune responses in the central nervous system, while excessive cleavage of sialic acid residues and consequently removing this checkpoint inhibitor may trigger lipid accumulation, protein aggregation, inflammation, and neurodegeneration.
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Affiliation(s)
- Christine Klaus
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Huan Liao
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | | | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Harald Neumann
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
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23
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Ronaldson PT, Davis TP. Regulation of blood-brain barrier integrity by microglia in health and disease: A therapeutic opportunity. J Cereb Blood Flow Metab 2020; 40:S6-S24. [PMID: 32928017 PMCID: PMC7687032 DOI: 10.1177/0271678x20951995] [Citation(s) in RCA: 189] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The blood-brain barrier (BBB) is a critical regulator of CNS homeostasis. It possesses physical and biochemical characteristics (i.e. tight junction protein complexes, transporters) that are necessary for the BBB to perform this physiological role. Microvascular endothelial cells require support from astrocytes, pericytes, microglia, neurons, and constituents of the extracellular matrix. This intricate relationship implies the existence of a neurovascular unit (NVU). NVU cellular components can be activated in disease and contribute to dynamic remodeling of the BBB. This is especially true of microglia, the resident immune cells of the brain, which polarize into distinct proinflammatory (M1) or anti-inflammatory (M2) phenotypes. Current data indicate that M1 pro-inflammatory microglia contribute to BBB dysfunction and vascular "leak", while M2 anti-inflammatory microglia play a protective role at the BBB. Understanding biological mechanisms involved in microglia activation provides a unique opportunity to develop novel treatment approaches for neurological diseases. In this review, we highlight characteristics of M1 proinflammatory and M2 anti-inflammatory microglia and describe how these distinct phenotypes modulate BBB physiology. Additionally, we outline the role of other NVU cell types in regulating microglial activation and highlight how microglia can be targeted for treatment of disease with a focus on ischemic stroke and Alzheimer's disease.
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Affiliation(s)
- Patrick T Ronaldson
- Department of Pharmacology, College of Medicine University of Arizona, Tucson, AZ, USA
| | - Thomas P Davis
- Department of Pharmacology, College of Medicine University of Arizona, Tucson, AZ, USA
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24
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Fatoba O, Itokazu T, Yamashita T. Microglia as therapeutic target in central nervous system disorders. J Pharmacol Sci 2020; 144:102-118. [PMID: 32921391 DOI: 10.1016/j.jphs.2020.07.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/19/2020] [Accepted: 07/07/2020] [Indexed: 12/17/2022] Open
Abstract
Chronic microglial activation is associated with the pathogenesis of several CNS disorders. Microglia show phenotypic diversity and functional complexity in diseased CNS. Thus, understanding the pathology-specific heterogeneity of microglial behavior is crucial for the future development of microglia-modulating therapy for variety of CNS disorders. This review summarizes up-to-date knowledge on how microglia contribute to CNS homeostasis during development and throughout adulthood. We discuss the heterogeneity of microglial phenotypes in the context of CNS disorders with an emphasis on neurodegenerative diseases, demyelinating diseases, CNS trauma, and epilepsy. We conclude this review with a discussion about the disease-specific heterogeneity of microglial function and how it could be exploited for therapeutic intervention.
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Affiliation(s)
- Oluwaseun Fatoba
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; WPI-Immunology Frontier Research Center, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Takahide Itokazu
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Toshihide Yamashita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; WPI-Immunology Frontier Research Center, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan; Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
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25
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Liao H, Klaus C, Neumann H. Control of Innate Immunity by Sialic Acids in the Nervous Tissue. Int J Mol Sci 2020; 21:ijms21155494. [PMID: 32752058 PMCID: PMC7432451 DOI: 10.3390/ijms21155494] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 12/11/2022] Open
Abstract
Sialic acids (Sias) are the most abundant terminal sugar residues of glycoproteins and glycolipids on the surface of mammalian cells. The nervous tissue is the organ with the highest expression level of Sias. The ‘sialylation’ of glycoconjugates is performed via sialyltransferases, whereas ‘desialylation’ is done by sialidases or is a possible consequence of oxidative damage. Sialic acid residues on the neural cell surfaces inhibit complement and microglial activation, as well as phagocytosis of the underlying structures, via binding to (i) complement factor H (CFH) or (ii) sialic acid-binding immunoglobulin-like lectin (SIGLEC) receptors. In contrast, activated microglial cells show sialidase activity that desialylates both microglia and neurons, and further stimulates innate immunity via microglia and complement activation. The desialylation conveys neurons to become susceptible to phagocytosis, as well as triggers a microglial phagocytosis-associated oxidative burst and inflammation. Dysfunctions of the ‘Sia–SIGLEC’ and/or ‘Sia–complement’ axes often lead to neurological diseases. Thus, Sias on glycoconjugates of the intact glycocalyx and its desialylation are major regulators of neuroinflammation.
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Affiliation(s)
| | | | - Harald Neumann
- Correspondence: ; Tel.: +49-228-6885-500; Fax: +49-228-6885-501
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26
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Yuan C, Aierken A, Xie Z, Li N, Zhao J, Qing H. The age-related microglial transformation in Alzheimer's disease pathogenesis. Neurobiol Aging 2020; 92:82-91. [PMID: 32408056 DOI: 10.1016/j.neurobiolaging.2020.03.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 03/11/2020] [Accepted: 03/31/2020] [Indexed: 12/15/2022]
Abstract
Neuroinflammatory responses mediated by microglia, the resident immune cells of the central nervous system, have long been a subject of study in the field of Alzheimer's disease (AD). Microglia express a wide range of receptors that act as molecular sensors, through which they can fulfill their various functions. In this review, we first analyzed the changes in the expression levels of microglial membrane receptors SR-A, TREM2, CD36, CD33, and CR3 in aging and AD and described the different roles of these receptors in amyloid-beta clearance and inflammatory responses. Two classical hallmarks of AD are extracellular amyloid-beta deposits and intracellular aggregated phosphorylated tau. In AD, microglia reaction was initially thought to be triggered by amyloid deposits. New evidence showed it also associated with increased phosphorylation of tau. However, which first appeared and induced activated microglia is not clear. Then we summarized diverse opinions on it. Besides, as AD is tightly linked to aging, and microglia changes dramatically on aging, yet the relative impacts of both aging and microglia are less frequently considered, so at last, we discussed the roles of aging microglia in AD. We hope to provide a reference for subsequent research.
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Affiliation(s)
- Chunxu Yuan
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biological Sciences, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Ailikemu Aierken
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biological Sciences, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Zhen Xie
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biological Sciences, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Nuomin Li
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biological Sciences, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Juan Zhao
- School of Materials Science and Engineering, Department of Materials Processing Engineering, Beijing Institute of Technology, Beijing, China.
| | - Hong Qing
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biological Sciences, School of Life Science, Beijing Institute of Technology, Beijing, China.
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27
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Sex-specific effects of developmental exposure to polychlorinated biphenyls on neuroimmune and dopaminergic endpoints in adolescent rats. Neurotoxicol Teratol 2020; 79:106880. [PMID: 32259577 DOI: 10.1016/j.ntt.2020.106880] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/17/2020] [Accepted: 03/24/2020] [Indexed: 12/22/2022]
Abstract
Exposure to environmental contaminants early in life can have long lasting consequences for physiological function. Polychlorinated biphenyls (PCBs) are a group of ubiquitous contaminants that perturb endocrine signaling and have been associated with altered immune function in children. In this study, we examined the effects of developmental exposure to PCBs on neuroimmune responses to an inflammatory challenge during adolescence. Sprague Dawley rat dams were exposed to a PCB mixture (Aroclor 1242, 1248, 1254, 1:1:1, 20 μg/kg/day) or oil control throughout pregnancy, and adolescent male and female offspring were injected with lipopolysaccharide (LPS, 50 μg/kg, ip) or saline control prior to euthanasia. Gene expression profiling was conducted in the hypothalamus, prefrontal cortex, striatum, and midbrain. In the hypothalamus, PCBs increased expression of genes involved in neuroimmune function, including those within the nuclear factor kappa b (NF-κB) complex, independent of LPS challenge. PCB exposure also increased expression of receptors for dopamine, serotonin, and estrogen in this region. In contrast, in the prefrontal cortex, PCB exposure blunted or induced irregular neuroimmune gene expression responses to LPS challenge. Moreover, neither PCB nor LPS exposure altered expression of neurotransmitter receptors throughout the mesocorticolimbic circuit. Almost all effects were present in males but not females, in agreement with the idea that male neuroimmune cells are more sensitive to perturbation and emphasizing the importance of studying both male and female subjects. Given that altered neuroimmune signaling has been implicated in mental health and substance abuse disorders that often begin during adolescence, these results highlight neuroimmune processes as another mechanism by which early life PCBs can alter brain function later in life.
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Golde TE. Harnessing Immunoproteostasis to Treat Neurodegenerative Disorders. Neuron 2019; 101:1003-1015. [PMID: 30897353 DOI: 10.1016/j.neuron.2019.02.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 02/05/2019] [Accepted: 02/15/2019] [Indexed: 12/12/2022]
Abstract
Immunoproteostasis is a term used to reflect interactions between the immune system and the proteinopathies that are presumptive "triggers" of many neurodegenerative disorders. The study of immunoproteostasis is bolstered by several observations. Mutations or rare variants in genes expressed in microglial cells, known to regulate immune functions, or both can cause, or alter risk for, various neurodegenerative disorders. Additionally, genetic association studies identify numerous loci harboring genes that encode proteins of known immune function that alter risk of developing Alzheimer's disease (AD) and other neurodegenerative proteinopathies. Further, preclinical studies reveal beneficial effects and liabilities of manipulating immune pathways in various neurodegenerative disease models. Although there are concerns that manipulation of the immune system may cause more harm than good, there is considerable interest in developing immune modulatory therapies for neurodegenerative disorders. Herein, I highlight the promise and challenges of harnessing immunoproteostasis to treat neurodegenerative proteinopathies.
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Affiliation(s)
- Todd E Golde
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, University of Florida, Gainesville, FL 32607, USA.
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29
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SRSF1 and PTBP1 Are trans-Acting Factors That Suppress the Formation of a CD33 Splicing Isoform Linked to Alzheimer's Disease Risk. Mol Cell Biol 2019; 39:MCB.00568-18. [PMID: 31208978 PMCID: PMC6712934 DOI: 10.1128/mcb.00568-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 06/08/2019] [Indexed: 12/19/2022] Open
Abstract
A single nucleotide polymorphism (SNP) in exon 2 of the CD33 gene is associated with reduced susceptibility to late-onset Alzheimer’s disease (AD) and causal for elevated mRNA lacking exon 2. In contrast to full-length CD33, transcripts lacking exon 2 result in CD33 protein unable to suppress activation responses in myeloid cells, including microglia. Currently, little is known about the regulation of CD33 exon 2 splicing. A single nucleotide polymorphism (SNP) in exon 2 of the CD33 gene is associated with reduced susceptibility to late-onset Alzheimer’s disease (AD) and causal for elevated mRNA lacking exon 2. In contrast to full-length CD33, transcripts lacking exon 2 result in CD33 protein unable to suppress activation responses in myeloid cells, including microglia. Currently, little is known about the regulation of CD33 exon 2 splicing. Using functional genomics and proteomic approaches, we found that SRSF1 and PTBP1 act as splicing enhancers to increase CD33 exon 2 inclusion in mRNA. Binding of PTBP1 to RNA sequences proximal to the intron 1-exon 2 splice junction is altered by the SNP and represents a potential mechanism behind the SNP-genotype dependent alternative splicing. Our studies also reveal that binding of SRSF1 to the CD33 RNA is not altered by the SNP genotype. Instead, a putative SRSF1 binding sequence at the 3′ end of exon 2 directs CD33 exon 2 inclusion into the mRNA, indicating that PTBP1 and SRSF1 promote full-length isoform expression through different mechanisms. Our findings shed light on molecular interactions that regulate CD33 exon 2 splicing, ultimately impacting receptor expression on the cell surface. These data aid in the understanding of CD33’s regulation of microglial signaling underpinning the AD genetic associations.
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30
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Rashid K, Akhtar-Schaefer I, Langmann T. Microglia in Retinal Degeneration. Front Immunol 2019; 10:1975. [PMID: 31481963 PMCID: PMC6710350 DOI: 10.3389/fimmu.2019.01975] [Citation(s) in RCA: 200] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 08/05/2019] [Indexed: 12/18/2022] Open
Abstract
The retina is a complex tissue with multiple cell layers that are highly ordered. Its sophisticated structure makes it especially sensitive to external or internal perturbations that exceed the homeostatic range. This necessitates the continuous surveillance of the retina for the detection of noxious stimuli. This task is mainly performed by microglia cells, the resident tissue macrophages which confer neuroprotection against transient pathophysiological insults. However, under sustained pathological stimuli, microglial inflammatory responses become dysregulated, often worsening disease pathology. In this review, we provide an overview of recent studies that depict microglial responses in diverse retinal pathologies that have degeneration and chronic immune reactions as key pathophysiological components. We also discuss innovative immunomodulatory therapy strategies that dampen the detrimental immunological responses to improve disease outcome.
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Affiliation(s)
- Khalid Rashid
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Isha Akhtar-Schaefer
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, Cologne, Germany
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31
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Estus S, Shaw BC, Devanney N, Katsumata Y, Press EE, Fardo DW. Evaluation of CD33 as a genetic risk factor for Alzheimer's disease. Acta Neuropathol 2019; 138:187-199. [PMID: 30949760 PMCID: PMC7035471 DOI: 10.1007/s00401-019-02000-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/22/2019] [Accepted: 03/30/2019] [Indexed: 12/23/2022]
Abstract
In 2011, genome-wide association studies implicated a polymorphism near CD33 as a genetic risk factor for Alzheimer's disease. This finding sparked interest in this member of the sialic acid-binding immunoglobulin-type lectin family which is linked to innate immunity. Subsequent studies found that CD33 is expressed in microglia in the brain and then investigated the molecular mechanism underlying the CD33 genetic association with Alzheimer's disease. The allele that protects from Alzheimer's disease acts predominately to increase a CD33 isoform lacking exon 2 at the expense of the prototypic, full-length CD33 that contains exon 2. Since this exon encodes the sialic acid ligand-binding domain, the finding that the loss of exon 2 was associated with decreased Alzheimer's disease risk was interpreted as meaning that a decrease in functional CD33 and its associated immune suppression was protective from Alzheimer's disease. However, this interpretation may need to be reconsidered given current findings that a genetic deletion which abrogates CD33 is not associated with Alzheimer's disease risk. Therefore, integrating currently available findings leads us to propose a model wherein the CD33 isoform lacking the ligand-binding domain represents a gain of function variant that reduces Alzheimer's disease risk.
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Affiliation(s)
- Steven Estus
- Department of Physiology and Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA.
| | - Benjamin C Shaw
- Department of Physiology and Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Nicholas Devanney
- Department of Physiology and Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Yuriko Katsumata
- Department of Biostatistics and Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | | | - David W Fardo
- Department of Biostatistics and Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
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32
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Akhtar-Schäfer I, Wang L, Krohne TU, Xu H, Langmann T. Modulation of three key innate immune pathways for the most common retinal degenerative diseases. EMBO Mol Med 2019; 10:emmm.201708259. [PMID: 30224384 PMCID: PMC6180304 DOI: 10.15252/emmm.201708259] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
This review highlights the role of three key immune pathways in the pathophysiology of major retinal degenerative diseases including diabetic retinopathy, age‐related macular degeneration, and rare retinal dystrophies. We first discuss the mechanisms how loss of retinal homeostasis evokes an unbalanced retinal immune reaction involving responses of local microglia and recruited macrophages, activity of the alternative complement system, and inflammasome assembly in the retinal pigment epithelium. Presenting these key mechanisms as complementary targets, we specifically emphasize the concept of immunomodulation as potential treatment strategy to prevent or delay vision loss. Promising molecules are ligands for phagocyte receptors, specific inhibitors of complement activation products, and inflammasome inhibitors. We comprehensively summarize the scientific evidence for this strategy from preclinical animal models, human ocular tissue analyses, and clinical trials evolving in the last few years.
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Affiliation(s)
- Isha Akhtar-Schäfer
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Luping Wang
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Tim U Krohne
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Heping Xu
- Centre for Experimental Medicine, The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry & Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany .,Center for Molecular Medicine, University of Cologne, Cologne, Germany
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Giridharan VV, Masud F, Petronilho F, Dal-Pizzol F, Barichello T. Infection-Induced Systemic Inflammation Is a Potential Driver of Alzheimer's Disease Progression. Front Aging Neurosci 2019; 11:122. [PMID: 31191296 PMCID: PMC6546917 DOI: 10.3389/fnagi.2019.00122] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/07/2019] [Indexed: 12/18/2022] Open
Affiliation(s)
- Vijayasree V Giridharan
- Department of Psychiatry and Behavioral Sciences, Translational Psychiatry Program, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Faisal Masud
- Department of Anesthesiology, Houston Methodist Hospital, Houston, TX, United States
| | - Fabricia Petronilho
- Health Sciences Unit, Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, University of South Santa Catarina, Tubarão, Brazil
| | - Felipe Dal-Pizzol
- Laboratory of Experimental Pathophysiology, Graduate Program in Health Sciences, University of Southern Santa Catarina, Criciúma, Brazil
| | - Tatiana Barichello
- Department of Psychiatry and Behavioral Sciences, Translational Psychiatry Program, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States.,Laboratory of Experimental Pathophysiology, Graduate Program in Health Sciences, University of Southern Santa Catarina, Criciúma, Brazil.,Graduate Program in Health Sciences, Laboratory of Neurosciences, Health Sciences Unit, University of Southern Santa Catarina (UNESC), Criciúma, Brazil
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McQuade A, Blurton-Jones M. Microglia in Alzheimer's Disease: Exploring How Genetics and Phenotype Influence Risk. J Mol Biol 2019; 431:1805-1817. [PMID: 30738892 PMCID: PMC6475606 DOI: 10.1016/j.jmb.2019.01.045] [Citation(s) in RCA: 129] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 01/29/2019] [Accepted: 01/29/2019] [Indexed: 01/25/2023]
Abstract
Research into the function of microglia has dramatically accelerated during the last few years, largely due to recent genetic findings implicating microglia in virtually every neurodegenerative disorder. In Alzheimer's disease (AD), a majority of risk loci discovered through genome-wide association studies were found in or near genes expressed most highly in microglia leading to the hypothesis that microglia play a much larger role in disease progression than previously thought. From this body of work produced in the last several years, we find that almost every function of microglia has been proposed to influence the progression of AD from altered phagocytosis and synaptic pruning to cytokine secretion and changes in trophic support. By studying key Alzheimer's risk genes such as TREM2, CD33, ABCA7, and MS4A6A, we will be able to distinguish true disease-modulatory pathways from the full range of microglial-related functions. To successfully carry out these experiments, more advanced microglial models are needed. Microglia are quite sensitive to their local environment, suggesting the need to more fully recapitulate an in vivo environment to study this highly plastic cell type. Likely only by combining the above approaches will the field fully elucidate the molecular pathways that regulate microglia and influence neurodegeneration, in turn uncovering potential new targets for future therapeutic development.
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Affiliation(s)
- Amanda McQuade
- Department of Neurobiology & Behavior, University of California Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA; Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA
| | - Mathew Blurton-Jones
- Department of Neurobiology & Behavior, University of California Irvine, Irvine, CA 92697, USA; Sue and Bill Gross Stem Cell Research Center, University of California Irvine, Irvine, CA 92697, USA; Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, CA 92697, USA.
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Contribution of Neurons and Glial Cells to Complement-Mediated Synapse Removal during Development, Aging and in Alzheimer's Disease. Mediators Inflamm 2018; 2018:2530414. [PMID: 30533998 PMCID: PMC6252206 DOI: 10.1155/2018/2530414] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/13/2018] [Accepted: 09/24/2018] [Indexed: 01/03/2023] Open
Abstract
Synapse loss is an early manifestation of pathology in Alzheimer's disease (AD) and is currently the best correlate to cognitive decline. Microglial cells are involved in synapse pruning during development via the complement pathway. Moreover, recent evidence points towards a key role played by glial cells in synapse loss during AD. However, further contribution of glial cells and the role of neurons to synapse pathology in AD remain not well understood. This review is aimed at comprehensively reporting the source and/or cellular localization in the CNS—in microglia, astrocytes, or neurons—of the triggering components (C1q, C3) of the classical complement pathway involved in synapse pruning in development, adulthood, and AD.
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Bisht K, Sharma K, Tremblay MÈ. Chronic stress as a risk factor for Alzheimer's disease: Roles of microglia-mediated synaptic remodeling, inflammation, and oxidative stress. Neurobiol Stress 2018; 9:9-21. [PMID: 29992181 PMCID: PMC6035903 DOI: 10.1016/j.ynstr.2018.05.003] [Citation(s) in RCA: 206] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 02/23/2018] [Accepted: 05/14/2018] [Indexed: 02/07/2023] Open
Abstract
Microglia are the predominant immune cells of the central nervous system (CNS) that exert key physiological roles required for maintaining CNS homeostasis, notably in response to chronic stress, as well as mediating synaptic plasticity, learning and memory. The repeated exposure to stress confers a higher risk of developing neurodegenerative diseases including sporadic Alzheimer's disease (AD). While microglia have been causally linked to amyloid beta (Aβ) accumulation, tau pathology, neurodegeneration, and synaptic loss in AD, they were also attributed beneficial roles, notably in the phagocytic elimination of Aβ. In this review, we discuss the interactions between chronic stress and AD pathology, overview the roles played by microglia in AD, especially focusing on chronic stress as an environmental risk factor modulating their function, and present recently-described microglial phenotypes associated with neuroprotection in AD. These microglial phenotypes observed under both chronic stress and AD pathology may provide novel opportunities for the development of better-targeted therapeutic interventions.
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Key Words
- ABCA7, ATP-binding cassette transporter A7
- AD, Alzheimer's disease
- APOE, Apolipoprotein E
- APP, amyloid precursor protein
- Alzheimer's disease
- Aβ, Amyloid beta
- BDNF, brain derived neurotrophic factor
- CD11b, cluster of differentiation molecule 11B
- CD33, cluster of differentiation 33
- CNS, central nervous system
- CR, complement receptor
- CRF, corticotropin releasing factor
- DAM, disease associated microglia
- DAP12, DNAX-activation protein 12
- Dark microglia
- FAD, Familial Alzheimer's disease
- FCRLS, Fc receptor-like S scavenger receptor
- GR, glucocorticoid receptor
- HPA axis, hypothalamic pituitary adrenocortical axis
- IBA1, ionized calcium-binding adapter molecule 1
- IL, interleukin
- LTP, long-term potentiation
- MGnD, microglia with a neurodegenerative phenotype
- MR, mineralocorticoid receptor
- Microglia
- Microglial phenotypes
- NADPH, nicotinamide adenine dinucleotide phosphate
- NFT, neurofibrillary tangles
- Neurodegeneration
- Neuroinflammation
- PS, presenilin
- ROS, reactive oxygen species
- Stress
- Synaptic remodeling
- TGFβ, transforming growth factor β
- TLR, Toll-like receptors
- TMEM119, transmembrane protein 119
- TNFα, tumor necrosis factor-α
- TREM2, triggering receptor expressed in myeloid cells 2
- TYROBP, TYRO protein tyrosine kinase binding protein
- mPFC, medial prefrontal cortex
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Affiliation(s)
- Kanchan Bisht
- Axe Neurosciences, CRCHU de Québec-Université Laval, Québec, QC, Canada
| | - Kaushik Sharma
- Axe Neurosciences, CRCHU de Québec-Université Laval, Québec, QC, Canada
| | - Marie-Ève Tremblay
- Axe Neurosciences, CRCHU de Québec-Université Laval, Québec, QC, Canada
- Département de médecine moléculaire, Université Laval, Québec, QC, Canada
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Lim SL, Tran DN, Zumkehr J, Chen C, Ghiaar S, Kieu Z, Villanueva E, Gallup V, Rodriguez-Ortiz CJ, Kitazawa M. Inhibition of hematopoietic cell kinase dysregulates microglial function and accelerates early stage Alzheimer's disease-like neuropathology. Glia 2018; 66:2700-2718. [PMID: 30277607 DOI: 10.1002/glia.23522] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 08/02/2018] [Accepted: 08/02/2018] [Indexed: 11/08/2022]
Abstract
Emerging evidence have posited that dysregulated microglia impair clearance and containment of amyloid-β (Aβ) species in the brain, resulting in aberrant buildup of Aβ and onset of Alzheimer's disease (AD). Hematopoietic cell kinase (Hck) is one of the key regulators of phagocytosis among the Src family tyrosine kinases (SFKs) in myeloid cells, and its expression is found to be significantly altered in AD brains. However, the role of Hck signaling in AD pathogenesis is unknown. We employed pharmacological inhibition and genetic ablation of Hck in BV2 microglial cells and J20 mouse model of AD, respectively, to evaluate the impact of Hck deficiency on Aβ-stimulated microglial phagocytosis, Aβ clearance, and resultant AD-like neuropathology. Our in vitro data reveal that pharmacological inhibition of SFKs/Hck in BV2 cells and genetic ablation of their downstream kinase, spleen tyrosine kinase (Syk), in primary microglia significantly attenuate Aβ oligomers-stimulated microglial phagocytosis. Whereas in Hck-deficient J20 mice, we observed exacerbated Aβ plaque burden, reduced microglial coverage, containment, and phagocytosis of Aβ plaques, and induced iNOS expression in plaque-associated microglial clusters. These multifactorial changes in microglial activities led to attenuated PSD95 levels in hippocampal DG and CA3 regions, but did not alter the postsynaptic dendritic spine morphology at the CA1 region nor cognitive function of the mice. Hck inhibition thus accelerates early stage AD-like neuropathology by dysregulating microglial function and inducing neuroinflammation. Our data implicate that Hck pathway plays a prominent role in regulating microglial neuroprotective function during the early stage of AD development.
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Affiliation(s)
- Siok Lam Lim
- Center for Occupational and Environmental Health, Department of Medicine, University of California, Irvine, California.,Molecular and Cell Biology, University of California, Merced, California
| | - Diana Nguyen Tran
- Molecular and Cell Biology, University of California, Merced, California
| | - Joannee Zumkehr
- Center for Occupational and Environmental Health, Department of Medicine, University of California, Irvine, California.,Molecular and Cell Biology, University of California, Merced, California
| | - Christine Chen
- Molecular and Cell Biology, University of California, Merced, California
| | - Sagar Ghiaar
- Molecular and Cell Biology, University of California, Merced, California
| | - Zanett Kieu
- Molecular and Cell Biology, University of California, Merced, California
| | | | - Victoria Gallup
- Molecular and Cell Biology, University of California, Merced, California
| | - Carlos J Rodriguez-Ortiz
- Center for Occupational and Environmental Health, Department of Medicine, University of California, Irvine, California.,Molecular and Cell Biology, University of California, Merced, California
| | - Masashi Kitazawa
- Center for Occupational and Environmental Health, Department of Medicine, University of California, Irvine, California.,Molecular and Cell Biology, University of California, Merced, California
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38
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Dey A, Hankey Giblin PA. Insights into Macrophage Heterogeneity and Cytokine-Induced Neuroinflammation in Major Depressive Disorder. Pharmaceuticals (Basel) 2018; 11:E64. [PMID: 29941796 PMCID: PMC6160985 DOI: 10.3390/ph11030064] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 06/21/2018] [Accepted: 06/22/2018] [Indexed: 12/13/2022] Open
Abstract
Over 350 million individuals suffer from depression, a psychiatric illness classified as major depressive disorder (MDD) with symptoms that include a loss of interest or pleasure in life accompanied by depressed mood. The present understanding of major depressive disorder does not encompass a systematic characterization of the neurobiological processes that drive the behavioral physiology in patients diagnosed with major depressive disorder. Psychiatric illness is a complex intersection between genetics, physiology, immunology and environmental stress. The increased attention to the relevance of depression has led to new discoveries that highlight the biological significance of ‘neuroinflammation’ and immunity underlying a spectrum of psychiatric illnesses. The process of neuroinflammation involves sentinel immune cells in the central nervous system (CNS). The activation and polarization of microglia, CNS-resident macrophages, modulates the production and secretion of pro-inflammatory cytokines implicated in the etiology of major depressive disorder, and this phenomenon has been aptly titled the ‘macrophage theory of depression’. Of particular interest are three hallmark cytokines, IL-6, TNFα and IL-1β, which have been studied extensively in basic research, cell-receptor signaling and drug development. The field of inflammasome-mediated neuroinflammation is an emerging area of MDD research that is providing new cellular insight into how macrophages mechanistically support cytokine-associated neuropathology, particularly in the case of IL-1β-associated inflammation in MDD. With the increasing number of individuals identified with depression, a comprehensive understanding of macrophage-cytokine signaling pathways in the CNS in depression is necessary for developing effective anti-depressant therapeutics.
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Affiliation(s)
- Adwitia Dey
- Center for Molecular Immunology and Infectious Diseases, The Pennsylvania State University, University Park, State College, PA 16802, USA.
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, State College, PA 16802, USA.
| | - Pamela A Hankey Giblin
- Center for Molecular Immunology and Infectious Diseases, The Pennsylvania State University, University Park, State College, PA 16802, USA.
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, State College, PA 16802, USA.
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Sekiya M, Wang M, Fujisaki N, Sakakibara Y, Quan X, Ehrlich ME, De Jager PL, Bennett DA, Schadt EE, Gandy S, Ando K, Zhang B, Iijima KM. Integrated biology approach reveals molecular and pathological interactions among Alzheimer's Aβ42, Tau, TREM2, and TYROBP in Drosophila models. Genome Med 2018; 10:26. [PMID: 29598827 PMCID: PMC5875009 DOI: 10.1186/s13073-018-0530-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 03/12/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Cerebral amyloidosis, neuroinflammation, and tauopathy are key features of Alzheimer's disease (AD), but interactions among these features remain poorly understood. Our previous multiscale molecular network models of AD revealed TYROBP as a key driver of an immune- and microglia-specific network that was robustly associated with AD pathophysiology. Recent genetic studies of AD further identified pathogenic mutations in both TREM2 and TYROBP. METHODS In this study, we systematically examined molecular and pathological interactions among Aβ, tau, TREM2, and TYROBP by integrating signatures from transgenic Drosophila models of AD and transcriptome-wide gene co-expression networks from two human AD cohorts. RESULTS Glial expression of TREM2/TYROBP exacerbated tau-mediated neurodegeneration and synergistically affected pathways underlying late-onset AD pathology, while neuronal Aβ42 and glial TREM2/TYROBP synergistically altered expression of the genes in synaptic function and immune modules in AD. CONCLUSIONS The comprehensive pathological and molecular data generated through this study strongly validate the causal role of TREM2/TYROBP in driving molecular networks in AD and AD-related phenotypes in flies.
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Affiliation(s)
- Michiko Sekiya
- 0000 0004 1791 9005grid.419257.cDepartment of Alzheimer’s Disease Research, National Center for Geriatrics and Gerontology, 7-430 Morioka-cho, Obu, Aichi 474-8511 Japan
| | - Minghui Wang
- 0000 0001 0670 2351grid.59734.3cDepartment of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, Room 8-111, Box 1498, New York, NY 10029 USA ,0000 0001 0670 2351grid.59734.3cIcahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY USA
| | - Naoki Fujisaki
- 0000 0004 1791 9005grid.419257.cDepartment of Alzheimer’s Disease Research, National Center for Geriatrics and Gerontology, 7-430 Morioka-cho, Obu, Aichi 474-8511 Japan ,0000 0001 0728 1069grid.260433.0Department of Experimental Gerontology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Japan
| | - Yasufumi Sakakibara
- 0000 0004 1791 9005grid.419257.cDepartment of Alzheimer’s Disease Research, National Center for Geriatrics and Gerontology, 7-430 Morioka-cho, Obu, Aichi 474-8511 Japan
| | - Xiuming Quan
- 0000 0004 1791 9005grid.419257.cDepartment of Alzheimer’s Disease Research, National Center for Geriatrics and Gerontology, 7-430 Morioka-cho, Obu, Aichi 474-8511 Japan
| | - Michelle E. Ehrlich
- 0000 0001 0670 2351grid.59734.3cDepartment of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, Room 8-111, Box 1498, New York, NY 10029 USA ,0000 0001 0670 2351grid.59734.3cDepartment of Neurology, Alzheimer’s Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY USA ,0000 0001 0670 2351grid.59734.3cDepartment of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY USA
| | - Philip L. De Jager
- 0000 0001 2285 2675grid.239585.0Center for translational & Computational Neuroimmunology, Department of Neurology, The Neurological Institute of New York, Columbia University Medical Center, New York, NY USA ,grid.66859.34Broad Institute, Cambridge, MA USA
| | - David A. Bennett
- 0000 0001 0705 3621grid.240684.cRush Alzheimer’s Disease Research Center and Department of Neurology, Rush University Medical Center, 1750 W. Congress Parkway, Chicago, IL 60612 USA
| | - Eric E. Schadt
- 0000 0001 0670 2351grid.59734.3cDepartment of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, Room 8-111, Box 1498, New York, NY 10029 USA ,0000 0001 0670 2351grid.59734.3cIcahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY USA
| | - Sam Gandy
- 0000 0001 0670 2351grid.59734.3cDepartment of Neurology, Alzheimer’s Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY USA ,0000 0001 0670 2351grid.59734.3cDepartment of Psychiatry and Alzheimer’s Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY USA ,0000 0004 5907 0628grid.480949.8Center for NFL Neurological Care, Department of Neurology, New York, NY USA ,0000 0004 0420 1184grid.274295.fJames J. Peters VA Medical Center, 130 West Kingsbridge Road, New York, NY USA
| | - Kanae Ando
- 0000 0001 1090 2030grid.265074.2Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo, Japan
| | - Bin Zhang
- Department of Genetics & Genomic Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, Room 8-111, Box 1498, New York, NY, 10029, USA. .,Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, USA. .,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, One Gustave L Levy Place, New York, NY, USA.
| | - Koichi M. Iijima
- 0000 0004 1791 9005grid.419257.cDepartment of Alzheimer’s Disease Research, National Center for Geriatrics and Gerontology, 7-430 Morioka-cho, Obu, Aichi 474-8511 Japan ,0000 0001 0728 1069grid.260433.0Department of Experimental Gerontology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Japan
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Condello C, Yuan P, Grutzendler J. Microglia-Mediated Neuroprotection, TREM2, and Alzheimer's Disease: Evidence From Optical Imaging. Biol Psychiatry 2018; 83:377-387. [PMID: 29169609 PMCID: PMC5767550 DOI: 10.1016/j.biopsych.2017.10.007] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 10/05/2017] [Accepted: 10/06/2017] [Indexed: 12/19/2022]
Abstract
Recent genetic studies have provided overwhelming evidence of the involvement of microglia-related molecular networks in the pathophysiology of Alzheimer's disease (AD). However, the precise mechanisms by which microglia alter the course of AD neuropathology remain poorly understood. Here we discuss current evidence of the neuroprotective functions of microglia with a focus on optical imaging studies that have revealed a role of these cells in the encapsulation of amyloid deposits ("microglia barrier"). This barrier modulates the degree of plaque compaction, amyloid fibril surface area, and insulation from adjacent axons thereby reducing neurotoxicity. We discuss findings implicating genetic variants of the microglia receptor, triggering receptor expressed on myeloid cells 2, in the increased risk of late onset AD. We provide evidence that increased AD risk may be at least partly mediated by deficient microglia polarization toward amyloid deposits, resulting in ineffective plaque encapsulation and reduced plaque compaction, which is associated with worsened axonal pathology. Finally, we propose possible avenues for therapeutic targeting of plaque-associated microglia with the goal of enhancing the microglia barrier and potentially reducing disease progression.
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Affiliation(s)
- Carlo Condello
- Institute for Neurodegenerative Diseases, Weill Institute for Neurosciences, University of California, San Francisco, CA 94158, USA,Department of Neurology, University of California, San Francisco, CA 94158, USA
| | - Peng Yuan
- Department of Biology, Stanford University, Palo Alto, CA 94305, USA
| | - Jaime Grutzendler
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut; Department of Neuroscience, Yale School of Medicine, New Haven, Connecticut.
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41
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Stamou M, Grodzki AC, van Oostrum M, Wollscheid B, Lein PJ. Fc gamma receptors are expressed in the developing rat brain and activate downstream signaling molecules upon cross-linking with immune complex. J Neuroinflammation 2018; 15:7. [PMID: 29306331 PMCID: PMC5756609 DOI: 10.1186/s12974-017-1050-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 12/22/2017] [Indexed: 12/22/2022] Open
Abstract
Background Exposure of the developing brain to immune mediators, including antibodies, is postulated to increase risk for neurodevelopmental disorders and neurodegenerative disease. It has been suggested that immunoglobulin G-immune complexes (IgG-IC) activate Fc gamma receptors (FcγR) expressed on neurons to modify signaling events in these cells. However, testing this hypothesis is hindered by a paucity of data regarding neuronal FcγR expression and function. Methods FcγR transcript expression in the hippocampus, cortex, and cerebellum of neonatal male and female rats was investigated ex vivo and in mixed cultures of primary hippocampal and cortical neurons and astrocytes using quantitative PCR analyses. Expression at the protein level in mixed cultures of primary hippocampal and cortical neurons and astrocytes was determined by immunocytochemistry, western blotting, proteotype analysis, and flow cytometry. The functionality of these receptors was assessed by measuring changes in intracellular calcium levels, Erk phosphorylation, and IgG internalization following stimulation with IgG-immune complexes. Results FcgrIa, FcgrIIa, FcgrIIb, FcgrIIIa, and Fcgrt transcripts were detectable in the cortex, hippocampus, and cerebellum at postnatal days 1 and 7. These transcripts were also present in primary hippocampal and cortical cell cultures, where their expression was modulated by IFNγ. Expression of FcγRIa, FcγRIIb, and FcγRIIIa, but not FcγRIIa or FcRn proteins, was confirmed in cultured hippocampal and cortical neurons and astrocytes at the single cell level. A subpopulation of these cells co-expressed the activating FcγRIa and the inhibitory FcγRIIb. Functional analyses demonstrated that exposure of hippocampal and cortical cell cultures to IgG-IC increases intracellular calcium and Erk phosphorylation and triggers FcγR-mediated internalization of IgG. Conclusions Our data demonstrate that developing neurons and astrocytes in the hippocampus and the cortex express signaling competent FcγR. These findings suggest that IgG antibodies may influence normal neurodevelopment or function via direct interactions with FcγR on non-immune cells in the brain. Electronic supplementary material The online version of this article (10.1186/s12974-017-1050-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marianna Stamou
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Ana Cristina Grodzki
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Marc van Oostrum
- Department of Health Sciences and Technology, Institute of Molecular Systems Biology, ETH Zurich, 8093, Zürich, Switzerland
| | - Bernd Wollscheid
- Department of Health Sciences and Technology, Institute of Molecular Systems Biology, ETH Zurich, 8093, Zürich, Switzerland
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.
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Tian L, Hui CW, Bisht K, Tan Y, Sharma K, Chen S, Zhang X, Tremblay ME. Microglia under psychosocial stressors along the aging trajectory: Consequences on neuronal circuits, behavior, and brain diseases. Prog Neuropsychopharmacol Biol Psychiatry 2017; 79:27-39. [PMID: 28095309 DOI: 10.1016/j.pnpbp.2017.01.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/30/2016] [Accepted: 01/13/2017] [Indexed: 12/18/2022]
Abstract
Mounting evidence indicates the importance of microglia for proper brain development and function, as well as in complex stress-related neuropsychiatric disorders and cognitive decline along the aging trajectory. Considering that microglia are resident immune cells of the brain, a homeostatic maintenance of their effector functions that impact neuronal circuitry, such as phagocytosis and secretion of inflammatory factors, is critical to prevent the onset and progression of these pathological conditions. However, the molecular mechanisms by which microglial functions can be properly regulated under healthy and pathological conditions are still largely unknown. We aim to summarize recent progress regarding the effects of psychosocial stress and oxidative stress on microglial phenotypes, leading to neuroinflammation and impaired microglia-synapse interactions, notably through our own studies of inbred mouse strains, and most importantly, to discuss about promising therapeutic strategies that take advantage of microglial functions to tackle such brain disorders in the context of adult psychosocial stress or aging-induced oxidative stress.
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Affiliation(s)
- Li Tian
- Neuroscience Center, University of Helsinki, Viikinkaari 4, Helsinki FIN-00014, Finland; Psychiatry Research Center, Beijing Huilongguan Hospital, Peking University, Beijing, China.
| | - Chin Wai Hui
- Axe Neurosciences, Centre de recherche du CHU de Québec, Québec, Canada
| | - Kanchan Bisht
- Axe Neurosciences, Centre de recherche du CHU de Québec, Québec, Canada
| | - Yunlong Tan
- Psychiatry Research Center, Beijing Huilongguan Hospital, Peking University, Beijing, China
| | - Kaushik Sharma
- Axe Neurosciences, Centre de recherche du CHU de Québec, Québec, Canada
| | - Song Chen
- Psychiatry Research Center, Beijing Huilongguan Hospital, Peking University, Beijing, China; Beijing Key Laboratory of Mental Disorders and Center of Schizophrenia, Beijing Institute for Brain Disorders, Beijing Anding Hospital, Capital Medical University, China
| | - Xiangyang Zhang
- Psychiatry Research Center, Beijing Huilongguan Hospital, Peking University, Beijing, China; Department of Psychiatry and Behavioral Sciences, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Marie-Eve Tremblay
- Axe Neurosciences, Centre de recherche du CHU de Québec, Québec, Canada.
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Intranasal post-cardiac arrest treatment with orexin-A facilitates arousal from coma and ameliorates neuroinflammation. PLoS One 2017; 12:e0182707. [PMID: 28957432 PMCID: PMC5619710 DOI: 10.1371/journal.pone.0182707] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/24/2017] [Indexed: 12/31/2022] Open
Abstract
Cardiac arrest (CA) entails significant risks of coma resulting in poor neurological and behavioral outcomes after resuscitation. Significant subsequent morbidity and mortality in post-CA patients are largely due to the cerebral and cardiac dysfunction that accompanies prolonged whole-body ischemia post-CA syndrome (PCAS). PCAS results in strong inflammatory responses including neuroinflammation response leading to poor outcome. Currently, there are no proven neuroprotective therapies to improve post-CA outcomes apart from therapeutic hypothermia. Furthermore, there are no acceptable approaches to promote cortical or cognitive arousal following successful return of spontaneous circulation (ROSC). Hypothalamic orexinergic pathway is responsible for arousal and it is negatively affected by neuroinflammation. However, whether activation of the orexinergic pathway can curtail neuroinflammation is unknown. We hypothesize that targeting the orexinergic pathway via intranasal orexin-A (ORXA) treatment will enhance arousal from coma and decrease the production of proinflammatory cytokines resulting in improved functional outcome after resuscitation. We used a highly validated CA rat model to determine the effects of intranasal ORXA treatment 30-minute post resuscitation. At 4hrs post-CA, the mRNA levels of proinflammatory markers (IL1β, iNOS, TNF-α, GFAP, CD11b) and orexin receptors (ORX1R and ORX2R) were examined in different brain regions. CA dramatically increased proinflammatory markers in all brain regions particularly in the prefrontal cortex, hippocampus and hypothalamus. Post-CA intranasal ORXA treatment significantly ameliorated the CA-induced neuroinflammatory markers in the hypothalamus. ORXA administration increased production of orexin receptors (ORX1R and ORX2R) particularly in hypothalamus. In addition, ORXA also resulted in early arousal as measured by quantitative electroencephalogram (EEG) markers, and recovery of the associated behavioral neurologic deficit scale score (NDS). Our results indicate that intranasal delivery of ORXA post-CA has an anti-inflammatory effect and accelerates cortical EEG and behavioral recovery. Beneficial outcomes from intranasal ORXA treatment lay the groundwork for therapeutic clinical approach to treating post-CA coma.
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Purine Signaling and Microglial Wrapping. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 949:147-165. [PMID: 27714688 DOI: 10.1007/978-3-319-40764-7_7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Microglial cells are highly dynamic cells with processes continuously moving to survey the surrounding territory. Microglia possess a broad variety of surface receptors and subtle changes in their microenvironment cause microglial cell processes to extend, retract, and interact with neuronal synaptic contacts. When the nervous system is disturbed, microglia activate, proliferate, and migrate to sites of injury in response to alert signals. Released nucleotides like ATP and UTP are among the wide range of molecules promoting microglial activation and guiding their migration and phagocytic function. The increased concentration of nucleotides in the extracellular space could be involved in the microglial wrapping found around injured neurons in various pathological conditions, especially after peripheral axotomy. Microglial wrappings isolate injured neurons from synaptic inputs and facilitate the molecular dialog between endangered or injured neurons and activated microglia. Astrocytes may also participate in neuronal ensheathment. Degradation of ATP by microglial ecto-nucleotidases and the expression of various purine receptors might be decisive in regulating the function of enwrapping glial cells and in determining the fate of damaged neurons, which may die or may regenerate their axons and survive.
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45
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Jay TR, von Saucken VE, Landreth GE. TREM2 in Neurodegenerative Diseases. Mol Neurodegener 2017; 12:56. [PMID: 28768545 PMCID: PMC5541421 DOI: 10.1186/s13024-017-0197-5] [Citation(s) in RCA: 252] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 07/20/2017] [Indexed: 12/12/2022] Open
Abstract
TREM2 variants have been identified as risk factors for Alzheimer's disease (AD) and other neurodegenerative diseases (NDDs). Because TREM2 encodes a receptor exclusively expressed on immune cells, identification of these variants conclusively demonstrates that the immune response can play an active role in the pathogenesis of NDDs. These TREM2 variants also confer the highest risk for developing Alzheimer's disease of any risk factor identified in nearly two decades, suggesting that understanding more about TREM2 function could provide key insights into NDD pathology and provide avenues for novel immune-related NDD biomarkers and therapeutics. The expression, signaling and function of TREM2 in NDDs have been extensively investigated in an effort to understand the role of immune function in disease pathogenesis and progression. We provide a comprehensive review of our current understanding of TREM2 biology, including new insights into the regulation of TREM2 expression, and TREM2 signaling and function across NDDs. While many open questions remain, the current body of literature provides clarity on several issues. While it is still often cited that TREM2 expression is decreased by pro-inflammatory stimuli, it is now clear that this is true in vitro, but inflammatory stimuli in vivo almost universally increase TREM2 expression. Likewise, while TREM2 function is classically described as promoting an anti-inflammatory phenotype, more than half of published studies demonstrate a pro-inflammatory role for TREM2, suggesting that its role in inflammation is much more complex. Finally, these components of TREM2 biology are applied to a discussion of how TREM2 impacts NDD pathologies and the latest assessment of how these findings might be applied to immune-directed clinical biomarkers and therapeutics.
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Affiliation(s)
- Taylor R. Jay
- Department of Neurosciences, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106 USA
| | - Victoria E. von Saucken
- Department of Neurosciences, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106 USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, 320 W 15th Street, Indianapolis, IN 46202 USA
| | - Gary E. Landreth
- Department of Neurosciences, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106 USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, 320 W 15th Street, Indianapolis, IN 46202 USA
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46
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Newly Formed Endothelial Cells Regulate Myeloid Cell Activity Following Spinal Cord Injury via Expression of CD200 Ligand. J Neurosci 2017; 37:972-985. [PMID: 28123029 DOI: 10.1523/jneurosci.2199-16.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 11/18/2016] [Accepted: 11/29/2016] [Indexed: 01/08/2023] Open
Abstract
The central nervous system (CNS) is endowed with several immune-related mechanisms that contribute to its protection and maintenance in homeostasis and under pathology. Here, we discovered an additional mechanism that controls inflammatory responses within the CNS milieu under injurious conditions, involving CD200 ligand (CD200L) expressed by newly formed endothelial cells. We observed that CD200L is constitutively expressed in the mouse healthy CNS by endothelial cells of the blood-cerebrospinal fluid barrier and of the spinal cord meninges, but not by the endothelium of the blood-spinal cord barrier. Following spinal cord injury (SCI), newly formed endothelial cells, located only at the epicenter of the lesion site, expressed CD200L. Moreover, in the absence of CD200L expression by CNS-resident cells, functional recovery of mice following SCI was impaired. High throughput single-cell flow cytometry image analysis following SCI revealed CD200L-dependent direct interaction between endothelial and local CD200R+ myeloid cells, including activated microglia and infiltrating monocyte-derived macrophages (mo-MΦ). Absence of CD200L signaling, both in vitro and in vivo, resulted in a higher inflammatory response of the encountering macrophages, manifested by elevation in mRNA expression of Tnfα and Il1β, increased intracellular TNFα immunoreactivity, and reduced expression levels of macrophage factors that are associated with resolution of inflammation, Dectin-1, CD206 (mannose receptor), and IL-4R. Collectively, our results highlight the importance of CD200-mediated immune dialogue between endothelial cells and the local resident microglia and infiltrating mo-MΦ within the lesion area, as a mechanism that contributes to regulation of inflammation following acute CNS injury. SIGNIFICANCE STATEMENT This manuscript focuses on a novel mechanism of inflammation-regulation following spinal cord injury (SCI), orchestrated by CD200-ligand (CD200L) expressed by newly formed endothelial cells within the lesion site. Our study reveals that, in homeostasis, CD200L is expressed by endothelial cells of the mouse blood-cerebrospinal fluid barrier and of the blood-leptomeningeal barrier, but not by endothelial cells of the blood-spinal cord barrier. Following SCI, newly formed endothelial cells located within the epicenter of the lesion site were found to express CD200L at time points that were shown to be critical for repair. Our results reveal a direct interaction between CD200L+ endothelial cells and CD200R+ microglia and macrophages, resulting in attenuated inflammation, biasing macrophage phenotype toward inflammation-resolving cells, and promotion of functional recovery following SCI.
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Czirr E, Castello NA, Mosher KI, Castellano JM, Hinkson IV, Lucin KM, Baeza-Raja B, Ryu JK, Li L, Farina SN, Belichenko NP, Longo FM, Akassoglou K, Britschgi M, Cirrito JR, Wyss-Coray T. Microglial complement receptor 3 regulates brain Aβ levels through secreted proteolytic activity. J Exp Med 2017; 214:1081-1092. [PMID: 28298456 PMCID: PMC5379986 DOI: 10.1084/jem.20162011] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/31/2017] [Accepted: 02/03/2017] [Indexed: 12/20/2022] Open
Abstract
Czirr et al. report that microglia lacking complement receptor 3 display increased extracellular Aβ degrading activity and that targeting the receptor with a small molecule increases Aβ clearance in vivo, thus identifying a microglial receptor as a novel therapeutic target. Recent genetic evidence supports a link between microglia and the complement system in Alzheimer’s disease (AD). In this study, we uncovered a novel role for the microglial complement receptor 3 (CR3) in the regulation of soluble β-amyloid (Aβ) clearance independent of phagocytosis. Unexpectedly, ablation of CR3 in human amyloid precursor protein–transgenic mice results in decreased, rather than increased, Aβ accumulation. In line with these findings, cultured microglia lacking CR3 are more efficient than wild-type cells at degrading extracellular Aβ by secreting enzymatic factors, including tissue plasminogen activator. Furthermore, a small molecule modulator of CR3 reduces soluble Aβ levels and Aβ half-life in brain interstitial fluid (ISF), as measured by in vivo microdialysis. These results suggest that CR3 limits Aβ clearance from the ISF, illustrating a novel role for CR3 and microglia in brain Aβ metabolism and defining a potential new therapeutic target in AD.
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Affiliation(s)
- Eva Czirr
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Nicholas A Castello
- Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA 94158
| | - Kira I Mosher
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Joseph M Castellano
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305.,Paul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305
| | - Izumi V Hinkson
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305.,Paul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305.,Center for Tissue Regeneration, Repair, and Restoration, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304
| | - Kurt M Lucin
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Bernat Baeza-Raja
- Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA 94158
| | - Jae Kyu Ryu
- Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA 94158
| | - Lulin Li
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305.,Paul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305.,Center for Tissue Regeneration, Repair, and Restoration, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304
| | - Sasha N Farina
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305.,Center for Tissue Regeneration, Repair, and Restoration, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304
| | - Nadia P Belichenko
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Frank M Longo
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - Katerina Akassoglou
- Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA 94158.,Department of Neurology, University of California, San Francisco, San Francisco, CA 94158
| | - Markus Britschgi
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305
| | - John R Cirrito
- Department of Neurology, Washington University, St. Louis, MO 63110.,Knight Alzheimer's Disease Research Center, Washington University Medical Center, St. Louis, MO 63110.,Hope Center for Neurological Disorders, Washington University, St. Louis, MO 63110
| | - Tony Wyss-Coray
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305 .,Paul F. Glenn Center for the Biology of Aging, Stanford University School of Medicine, Stanford, CA 94305.,Center for Tissue Regeneration, Repair, and Restoration, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304
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48
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de Vries I, Busse C, Kopatz J, Neumann H, Beutel S, Scheper T. Polysialic acid production using Escherichia coli K1 in a disposable bag reactor. Eng Life Sci 2017; 17:723-731. [PMID: 32624817 DOI: 10.1002/elsc.201600220] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 01/05/2017] [Accepted: 01/17/2017] [Indexed: 12/12/2022] Open
Abstract
Polysialic acid (polySia), consisting of α-(2,8)-linked N-acetylneuraminic acid monomers plays a crucial role in many biological processes. This study presents a novel process for the production of endogenous polySia using Escherichia coli K1 in a disposable bag reactor with wave-induced mixing. Disposable bag reactors provide easy and fast production in terms of regulatory requirements as GMP, flexibility, and can easily be adjusted to larger production capacities not only by scale up but also by parallelization. Due to the poor oxygen transfer rate compared to a stirred tank reactor, pure oxygen was added during the cultivation to avoid oxygen limitation. During the exponential growth phase the growth rate was 0.61 h-1. Investigation of stress-related product release from the cell surface showed no significant differences between the disposable bag reactor with wave-induced mixing and the stirred tank reactor. After batch cultivation a cell dry weight of 6.8 g L-1 and a polySia concentration of 245 mg L-1 were reached. The total protein concentration in the supernatant was 132 mg L-1. After efficient and time-saving downstream processing characterization of the final product showed a protein content of below 0.04 mgprotein/gpolySia and a maximal chain length of ∼90 degree of polymerization.
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Affiliation(s)
- Ingo de Vries
- Institute of Technical Chemistry Leibniz University Hannover Hannover Germany
| | - Christoph Busse
- Institute of Technical Chemistry Leibniz University Hannover Hannover Germany
| | - Jens Kopatz
- Institute of Reconstructive Neurobiology University of Bonn Bonn Germany
| | - Harald Neumann
- Institute of Reconstructive Neurobiology University of Bonn Bonn Germany
| | - Sascha Beutel
- Institute of Technical Chemistry Leibniz University Hannover Hannover Germany
| | - Thomas Scheper
- Institute of Technical Chemistry Leibniz University Hannover Hannover Germany
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49
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Psychosocial stress on neuroinflammation and cognitive dysfunctions in Alzheimer's disease: the emerging role for microglia? Neurosci Biobehav Rev 2017; 77:148-164. [PMID: 28185874 DOI: 10.1016/j.neubiorev.2017.01.046] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 01/20/2017] [Accepted: 01/31/2017] [Indexed: 01/22/2023]
Abstract
Chronic psychosocial stress is increasingly recognized as a risk factor for late-onset Alzheimer's disease (LOAD) and associated cognitive deficits. Chronic stress also primes microglia and induces inflammatory responses in the adult brain, thereby compromising synapse-supportive roles of microglia and deteriorating cognitive functions during aging. Substantial evidence demonstrates that failure of microglia to clear abnormally accumulating amyloid-beta (Aβ) peptide contributes to neuroinflammation and neurodegeneration in AD. Moreover, genome-wide association studies have linked variants in several immune genes, such as TREM2 and CD33, the expression of which in the brain is restricted to microglia, with cognitive dysfunctions in LOAD. Thus, inflammation-promoting chronic stress may create a vicious cycle of aggravated microglial dysfunction accompanied by increased Aβ accumulation, collectively exacerbating neurodegeneration. Surprisingly, however, little is known about whether and how chronic stress contributes to microglia-mediated neuroinflammation that may underlie cognitive impairments in AD. This review aims to summarize the currently available clinical and preclinical data and outline potential molecular mechanisms linking stress, microglia and neurodegeneration, to foster future research in this field.
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50
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Kano F, Matsubara K, Ueda M, Hibi H, Yamamoto A. Secreted Ectodomain of Sialic Acid-Binding Ig-Like Lectin-9 and Monocyte Chemoattractant Protein-1 Synergistically Regenerate Transected Rat Peripheral Nerves by Altering Macrophage Polarity. Stem Cells 2016; 35:641-653. [PMID: 27862629 DOI: 10.1002/stem.2534] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 09/30/2016] [Accepted: 10/10/2016] [Indexed: 12/24/2022]
Abstract
Peripheral nerves (PNs) exhibit remarkable self-repairing reparative activity after a simple crush or cut injury. However, the neuronal transection involving a nerve gap overwhelms their repairing activity and causes persistent paralysis. Here, we show that an implantation of the serum-free conditioned medium from stem cells from human exfoliated deciduous teeth (SHED-CM) immersed in a collagen sponge into the nerve gap formed by rat facial nerves transection restored the neurological function. In contrast, SHED-CM specifically depleted of a set of anti-inflammatory M2 macrophage inducers, monocyte chemoattractant protein-1 (MCP-1) and the secreted ectodomain of sialic acid-binding Ig-like lectin-9 (sSiglec-9) lost the ability to restore neurological function in this model. Notably, the combination of MCP-1 and sSiglec-9 induced the polarization of M2 macrophages in vitro, resulting in the expression of multiple trophic factors that enhanced proliferation, migration, and differentiation of Schwann cells, blood vessel formation, and nerve fiber extension. Furthermore, the implantation of a collagen graft containing MCP-1/sSiglec-9 into the nerve gap induced anti-inflammatory M2 macrophage polarization, generated a Schwann-cell bridge instead of fibrotic scar, induced axonal regrowth, and restored nerve function. The specific elimination of M2 macrophages by Mannosylated-Clodrosome suppressed the MCP-1/sSiglec-9-mediated neurological recovery. Taken together, our data suggest that MCP-1/sSiglec-9 regenerates PNs by inducing tissue-repairing M2 macrophages and may provide therapeutic benefits for severe peripheral nerve injuries. Stem Cells 2017;35:641-653.
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Affiliation(s)
- Fumiya Kano
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - Kohki Matsubara
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - Minoru Ueda
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - Hideharu Hibi
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - Akihito Yamamoto
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
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