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Yu C, Deng XJ, Xu D. Microglia in epilepsy. Neurobiol Dis 2023; 185:106249. [PMID: 37536386 DOI: 10.1016/j.nbd.2023.106249] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 07/07/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023] Open
Abstract
Epilepsy is one of most common chronic neurological disorders, and the antiseizure medications developed by targeting neurocentric mechanisms have not effectively reduced the proportion of patients with drug-resistant epilepsy. Further exploration of the cellular or molecular mechanism of epilepsy is expected to provide new options for treatment. Recently, more and more researches focus on brain network components other than neurons, among which microglia have attracted much attention for their diverse biological functions. As the resident immune cells of the central nervous system, microglia have highly plastic transcription, morphology and functional characteristics, which can change dynamically in a context-dependent manner during the progression of epilepsy. In the pathogenesis of epilepsy, highly reactive microglia interact with other components in the epileptogenic network by performing crucial functions such as secretion of soluble factors and phagocytosis, thus continuously reshaping the landscape of the epileptic brain microenvironment. Indeed, microglia appear to be both pro-epileptic and anti-epileptic under the different spatiotemporal contexts of disease, rendering interventions targeting microglia biologically complex and challenging. This comprehensive review critically summarizes the pathophysiological role of microglia in epileptic brain homeostasis alterations and explores potential therapeutic or modulatory targets for epilepsy targeting microglia.
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Affiliation(s)
- Cheng Yu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, Hubei Province 430022, China
| | - Xue-Jun Deng
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, Hubei Province 430022, China
| | - Da Xu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, Hubei Province 430022, China.
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Zhou J, Lin S, Hu Q, Li X, Chen X, Luo L, Ye S, Liu W, Ye J. Microglial CD11b Knockout Contributes to Axonal Debris Clearance and Axonal Degradation Attenuation via IGF-1 After Acute Optic Nerve Injury. Invest Ophthalmol Vis Sci 2023; 64:7. [PMID: 37145604 PMCID: PMC10168008 DOI: 10.1167/iovs.64.5.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023] Open
Abstract
Purpose Microglial clearance of axonal debris is an essential response for management of traumatic optic neuropathy. Inadequate removal of axonal debris leads to increased inflammation and axonal degeneration after traumatic optic neuropathy. The present study investigated the role of CD11b (Itgam) in axonal debris clearance and axonal degeneration. Methods Western blot and immunofluorescence were used to detect CD11b expression in the mouse optic nerve crush (ONC) model. Bioinformatics analysis predicted the possible role of CD11b. Cholera toxin subunit B (CTB) and zymosan were used to assay phagocytosis by microglia in vivo and in vitro, respectively. CTB was also used to label functionally intact axons after ONC. Results CD11b is abundantly expressed after ONC and participates in phagocytosis. Microglia from Itgam-/- mice exhibited more significant phagocytosis of axonal debris than wild-type microglia. In vitro experiments confirmed that the CD11b gene defect in M2 microglia leads to increased insulin-like growth factor-1 secretion and thus promotes phagocytosis. Lastly, following ONC, Itgam-/- mice exhibited elevated expression of neurofilament heavy peptide and Tuj1, along with more intact CTB-labeled axons when compared with wild-type mice. Moreover, the inhibition of insulin-like growth factor-1 decreased CTB labeling in Itgam-/- mice after injury. Conclusions CD11b limits microglial phagocytosis of axonal debris in traumatic optic neuropathy, as demonstrated by increased phagocytosis with CD11b knockout. The inhibition of CD11b activity may be a novel approach to promote central nerve repair.
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Affiliation(s)
- Jiaxing Zhou
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Third Military Medical University (Army Medical University), Chongqing, China
| | - Sen Lin
- Department of Neurology, Xinqiao Hospital and The Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Qiumei Hu
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Third Military Medical University (Army Medical University), Chongqing, China
| | - Xue Li
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Third Military Medical University (Army Medical University), Chongqing, China
| | - Xi Chen
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Third Military Medical University (Army Medical University), Chongqing, China
| | - Linlin Luo
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Third Military Medical University (Army Medical University), Chongqing, China
| | - Shiyang Ye
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Wei Liu
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Third Military Medical University (Army Medical University), Chongqing, China
| | - Jian Ye
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Third Military Medical University (Army Medical University), Chongqing, China
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Xu Z, Zhang G, Zhang X, Lei Y, Sun Y, He Y, Yang F, Nan W, Xing X, Li Y, Lin J. Menstrual blood-derived endometrial stem cells inhibit neuroinflammation by regulating microglia through the TLR4/MyD88/NLRP3/Casp1 pathway. Int J Biochem Cell Biol 2023; 157:106386. [PMID: 36754162 DOI: 10.1016/j.biocel.2023.106386] [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: 08/22/2022] [Revised: 12/28/2022] [Accepted: 02/03/2023] [Indexed: 02/09/2023]
Abstract
Neuroinflammation is a common response in various neurological disorders. Mesenchymal stem cell-based treatment has become a promising therapy for neuroinflammation-associated diseases. However, the effects of mesenchymal stem cells are controversial, and the underlying mechanism is incompletely understood. In the present study, menstrual blood-derived endometrial stem cells were intravenously transplanted into a mouse model of neuroinflammation established by peripheral injection of lipopolysaccharide. Microglial cells challenged with lipopolysaccharide were cultured with conditioned medium from endometrial stem cells. The levels of cytokines were detected by enzyme-linked immunosorbent assay. Cell proliferation and death were detected by Cell Counting Kit 8 and flow cytometry, respectively. The expression levels of Toll-like receptor 4 (TLR4), myeloid differentiation primary response gene 88 (MyD88), NLR family pyrin domain containing 3 (NLRP3) and caspase 1 (Casp1) were evaluated by western blotting. The results showed that intravenous transplantation of endometrial stem cells downregulated proinflammatory factors and upregulated anti-inflammatory factors in the brain of mice with neuroinflammation. Conditioned medium suppressed the inflammatory reaction and hyperactivation of microglial cells and protected microglial cells from cell death induced by lipopolysaccharide in vitro. The expression of TLR4, MyD88, NLRP3 and Casp1 in the brain of mice with neuroinflammation and in lipopolysaccharide-stimulated microglial cells was downregulated by endometrial stem cells and conditioned medium, respectively. These data suggested that menstrual blood-derived endometrial stem cells may suppress neuroinflammatory reactions partially by regulating microglia through the TLR4/MyD88/NLRP3/Casp1 signalling pathway. Our findings may be very useful for the development of an alternative stem cell-based therapy for neuroinflammation-associated disorders.
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Affiliation(s)
- Zhihao Xu
- School of Life Science and Technology, Xinxiang Medical University, Xinxiang 453003, Henan, PR China; Stem Cells and Biotherapy Engineering and Technology Research Center of Henan, Henan Joint International Research Laboratory of Stem Cell Medicine, National Joint Engineering Laboratory of Stem Cells and Biotherapy, Xinxiang 453003, Henan, PR China.
| | - Guoqing Zhang
- School of Life Science and Technology, Xinxiang Medical University, Xinxiang 453003, Henan, PR China; Stem Cells and Biotherapy Engineering and Technology Research Center of Henan, Henan Joint International Research Laboratory of Stem Cell Medicine, National Joint Engineering Laboratory of Stem Cells and Biotherapy, Xinxiang 453003, Henan, PR China
| | - Xiaoyue Zhang
- School of Life Science and Technology, Xinxiang Medical University, Xinxiang 453003, Henan, PR China; Stem Cells and Biotherapy Engineering and Technology Research Center of Henan, Henan Joint International Research Laboratory of Stem Cell Medicine, National Joint Engineering Laboratory of Stem Cells and Biotherapy, Xinxiang 453003, Henan, PR China
| | - Yu Lei
- School of Life Science and Technology, Xinxiang Medical University, Xinxiang 453003, Henan, PR China
| | - Yuliang Sun
- Stem Cells and Biotherapy Engineering and Technology Research Center of Henan, Henan Joint International Research Laboratory of Stem Cell Medicine, National Joint Engineering Laboratory of Stem Cells and Biotherapy, Xinxiang 453003, Henan, PR China; School of Medical Engineering, Xinxiang Medical University, Xinxiang 453003, Henan, PR China
| | - Ya'nan He
- Zhongyuan Stem Cell Research Institute, Xinxiang 453003, Henan, PR China
| | - Fen Yang
- Stem Cells and Biotherapy Engineering and Technology Research Center of Henan, Henan Joint International Research Laboratory of Stem Cell Medicine, National Joint Engineering Laboratory of Stem Cells and Biotherapy, Xinxiang 453003, Henan, PR China; School of Medical Engineering, Xinxiang Medical University, Xinxiang 453003, Henan, PR China
| | - Wenbin Nan
- School of Life Science and Technology, Xinxiang Medical University, Xinxiang 453003, Henan, PR China
| | - Xuekun Xing
- College of Public Health, Guilin Medical University, Guilin 541199, Guangxi, PR China
| | - Yonghai Li
- School of Life Science and Technology, Xinxiang Medical University, Xinxiang 453003, Henan, PR China; Stem Cells and Biotherapy Engineering and Technology Research Center of Henan, Henan Joint International Research Laboratory of Stem Cell Medicine, National Joint Engineering Laboratory of Stem Cells and Biotherapy, Xinxiang 453003, Henan, PR China
| | - Juntang Lin
- School of Life Science and Technology, Xinxiang Medical University, Xinxiang 453003, Henan, PR China; Stem Cells and Biotherapy Engineering and Technology Research Center of Henan, Henan Joint International Research Laboratory of Stem Cell Medicine, National Joint Engineering Laboratory of Stem Cells and Biotherapy, Xinxiang 453003, Henan, PR China; School of Medical Engineering, Xinxiang Medical University, Xinxiang 453003, Henan, PR China.
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Dehghan M, Fathinejad F, Farzaei MH, Barzegari E. In silico unraveling of molecular anti-neurodegenerative profile of Citrus medica flavonoids against novel pharmaceutical targets. CHEMICAL PAPERS 2022. [DOI: 10.1007/s11696-022-02496-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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5
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Pedicone C, Fernandes S, Matera A, Meyer ST, Loh S, Ha JH, Bernard D, Chisholm JD, Paolicelli RC, Kerr WG. Discovery of a novel SHIP1 agonist that promotes degradation of lipid-laden phagocytic cargo by microglia. iScience 2022; 25:104170. [PMID: 35465359 PMCID: PMC9020084 DOI: 10.1016/j.isci.2022.104170] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/31/2021] [Accepted: 03/24/2022] [Indexed: 12/01/2022] Open
Abstract
Here, we describe the use of artificial intelligence to identify novel agonists of the SH2-containing 5′ inositol phosphatase 1 (SHIP1). One of the compounds, K306, represents the most potent agonist identified to date. We find that K306 exhibits selectivity for SHIP1 vs. the paralog enzyme SHIP2, and this activation does not require the C2 domain of SHIP1 which other known SHIP1 agonists require. Thus, K306 represents a new class of SHIP1 agonists with a novel mode of agonism. Importantly, we find that K306 can suppress induction of inflammatory cytokines and iNOS in macrophages or microglia, but not by their SHIP1-deficient counterparts. K306 also reduces TNF-α production in vivo in an LPS-induced endotoxemia assay. Finally, we show that K306 enhances phagolysosomal degradation of synaptosomes and dead neurons by microglia revealing a novel function for SHIP1 that might be exploited therapeutically in dementia. Discovery of a potent SHIP1 selective agonist (K306) via artificial intelligence SHIP1 agonism via K306 is independent of the C2 domain and increases PI(3,4)P2 levels K306 reduces IL-6, TNF-α, and iNOS induction in microglia and macrophages K306 promotes phagocytic degradation of lipid-laden but not protein cargo in microglia
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Affiliation(s)
- Chiara Pedicone
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Sandra Fernandes
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Alessandro Matera
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Shea T Meyer
- Chemistry Department, Syracuse University, Syracuse, NY 13210, USA
| | - Stewart Loh
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Jeung-Hoi Ha
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | | | - John D Chisholm
- Chemistry Department, Syracuse University, Syracuse, NY 13210, USA
| | | | - William G Kerr
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY 13210, USA.,Chemistry Department, Syracuse University, Syracuse, NY 13210, USA
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Hwang D, Seyedsadr MS, Ishikawa LLW, Boehm A, Sahin Z, Casella G, Jang S, Gonzalez MV, Garifallou JP, Hakonarson H, Zhang W, Xiao D, Rostami A, Zhang GX, Ciric B. CSF-1 maintains pathogenic but not homeostatic myeloid cells in the central nervous system during autoimmune neuroinflammation. Proc Natl Acad Sci U S A 2022; 119:e2111804119. [PMID: 35353625 PMCID: PMC9168454 DOI: 10.1073/pnas.2111804119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 01/14/2022] [Indexed: 12/16/2022] Open
Abstract
The receptor for colony stimulating factor 1 (CSF-1R) is important for the survival and function of myeloid cells that mediate pathology during experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). CSF-1 and IL-34, the ligands of CSF-1R, have similar bioactivities but distinct tissue and context-dependent expression patterns, suggesting that they have different roles. This could be the case in EAE, given that CSF-1 expression is up-regulated in the CNS, while IL-34 remains constitutively expressed. We found that targeting CSF-1 with neutralizing antibody halted ongoing EAE, with efficacy superior to CSF-1R inhibitor BLZ945, whereas IL-34 neutralization had no effect, suggesting that pathogenic myeloid cells were maintained by CSF-1. Both anti–CSF-1 and BLZ945 treatment greatly reduced the number of monocyte-derived cells and microglia in the CNS. However, anti–CSF-1 selectively depleted inflammatory microglia and monocytes in inflamed CNS areas, whereas BLZ945 depleted virtually all myeloid cells, including quiescent microglia, throughout the CNS. Anti–CSF-1 treatment reduced the size of demyelinated lesions and microglial activation in the gray matter. Lastly, we found that bone marrow–derived immune cells were the major mediators of CSF-1R–dependent pathology, while microglia played a lesser role. Our findings suggest that targeting CSF-1 could be effective in ameliorating MS pathology, while preserving the homeostatic functions of myeloid cells, thereby minimizing risks associated with ablation of CSF-1R–dependent cells.
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Affiliation(s)
- Daniel Hwang
- Department of Neurology, Jefferson Hospital for Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
| | - Maryam S. Seyedsadr
- Department of Neurology, Jefferson Hospital for Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
| | | | - Alexandra Boehm
- Department of Neurology, Jefferson Hospital for Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
| | - Ziver Sahin
- Department of Neurology, Jefferson Hospital for Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
| | - Giacomo Casella
- Department of Neurology, Jefferson Hospital for Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
| | - Soohwa Jang
- Department of Neurology, Jefferson Hospital for Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
| | - Michael V. Gonzalez
- The Children’s Hospital of Philadelphia, Abramson Research Center, Center for Applied Genomics, Philadelphia, PA 19104
| | - James P. Garifallou
- The Children’s Hospital of Philadelphia, Abramson Research Center, Center for Applied Genomics, Philadelphia, PA 19104
| | - Hakon Hakonarson
- The Children’s Hospital of Philadelphia, Abramson Research Center, Center for Applied Genomics, Philadelphia, PA 19104
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Weifeng Zhang
- Department of Neurology, Jefferson Hospital for Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
| | - Dan Xiao
- Department of Neurology, Jefferson Hospital for Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
| | - Abdolmohamad Rostami
- Department of Neurology, Jefferson Hospital for Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
| | - Guang-Xian Zhang
- Department of Neurology, Jefferson Hospital for Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
| | - Bogoljub Ciric
- Department of Neurology, Jefferson Hospital for Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
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Activación de la microglía en el hipocampo asociada con lesión del nervio facial. BIOMÉDICA 2022; 42:109-206. [PMID: 35471181 PMCID: PMC9048578 DOI: 10.7705/biomedica.6216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Indexed: 11/21/2022]
Abstract
Introducción. Las lesiones del nervio facial afectan la plasticidad a largo plazo en el hipocampo, así como la memoria de reconocimiento de objetos y la memoria espacial, dos procesos dependientes de esta estructura. Objetivo. Caracterizar en ratas el efecto de la lesión unilateral del nervio facial sobre la activación de células de la microglía en el hipocampo contralateral.Materiales y métodos. Se hicieron experimentos de inmunohistoquímica para detectar células de la microglía en el hipocampo de ratas sometidas a lesión irreversible del nervio facial. Los animales se sacrificaron en distintos momentos después de la lesión, para evaluar la evolución de la proliferación (densidad de células) y la activación (área celular) de la microglía en el tejido del hipocampo. Los tejidos cerebrales de los animales de control se compararon con los de animales lesionados sacrificados en los días 1, 3, 7, 21 y 35 después de la lesión.Resultados. Las células de la microglía en el hipocampo de animales con lesión del nervio facial mostraron signos de proliferación y activación a los 3, 7 y 21 días después de la lesión. Sin embargo, al cabo de cinco semanas, estas modificaciones se revirtieron, a pesar de que no hubo recuperación funcional de la parálisis facial.Conclusiones. La lesión irreversible del nervio facial produce proliferación y activación temprana y transitoria de las células de la microglía en el hipocampo. Estos cambios podrían estar asociados con las modificaciones electrofisiológicas y las alteraciones comportamentales dependientes del hipocampo descritas recientemente.
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8
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Chu E, Mychasiuk R, Hibbs ML, Semple BD. Dysregulated phosphoinositide 3-kinase signaling in microglia: shaping chronic neuroinflammation. J Neuroinflammation 2021; 18:276. [PMID: 34838047 PMCID: PMC8627624 DOI: 10.1186/s12974-021-02325-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 11/15/2021] [Indexed: 12/15/2022] Open
Abstract
Microglia are integral mediators of innate immunity within the mammalian central nervous system. Typical microglial responses are transient, intending to restore homeostasis by orchestrating the removal of pathogens and debris and the regeneration of damaged neurons. However, prolonged and persistent microglial activation can drive chronic neuroinflammation and is associated with neurodegenerative disease. Recent evidence has revealed that abnormalities in microglial signaling pathways involving phosphatidylinositol 3-kinase (PI3K) and protein kinase B (AKT) may contribute to altered microglial activity and exacerbated neuroimmune responses. In this scoping review, the known and suspected roles of PI3K-AKT signaling in microglia, both during health and pathological states, will be examined, and the key microglial receptors that induce PI3K-AKT signaling in microglia will be described. Since aberrant signaling is correlated with neurodegenerative disease onset, the relationship between maladapted PI3K-AKT signaling and the development of neurodegenerative disease will also be explored. Finally, studies in which microglial PI3K-AKT signaling has been modulated will be highlighted, as this may prove to be a promising therapeutic approach for the future treatment of a range of neuroinflammatory conditions.
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Affiliation(s)
- Erskine Chu
- Department of Immunology and Pathology, Central Clinical School, Monash University, Level 6, 89 Commercial Road, Melbourne, VIC, 3004, Australia
- Department of Neuroscience, Central Clinical School, Monash University, Level 6, 99 Commercial Road, Melbourne, VIC, 3004, Australia
| | - Richelle Mychasiuk
- Department of Neuroscience, Central Clinical School, Monash University, Level 6, 99 Commercial Road, Melbourne, VIC, 3004, Australia
- Department of Neurology, Alfred Health, Prahran, VIC, 3181, Australia
| | - Margaret L Hibbs
- Department of Immunology and Pathology, Central Clinical School, Monash University, Level 6, 89 Commercial Road, Melbourne, VIC, 3004, Australia.
| | - Bridgette D Semple
- Department of Neuroscience, Central Clinical School, Monash University, Level 6, 99 Commercial Road, Melbourne, VIC, 3004, Australia.
- Department of Neurology, Alfred Health, Prahran, VIC, 3181, Australia.
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, VIC, 3050, Australia.
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Wyatt-Johnson SK, Sommer AL, Shim KY, Brewster AL. Suppression of Microgliosis With the Colony-Stimulating Factor 1 Receptor Inhibitor PLX3397 Does Not Attenuate Memory Defects During Epileptogenesis in the Rat. Front Neurol 2021; 12:651096. [PMID: 34149593 PMCID: PMC8209304 DOI: 10.3389/fneur.2021.651096] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 05/11/2021] [Indexed: 12/03/2022] Open
Abstract
Events of status epilepticus (SE) trigger the development of temporal lobe epilepsy (TLE), a type of focal epilepsy that is commonly drug-resistant and is highly comorbid with cognitive deficits. While SE-induced hippocampal injury, accompanied by gliosis and neuronal loss, typically disrupts cognitive functions resulting in memory defects, it is not definitively known how. Our previous studies revealed extensive hippocampal microgliosis that peaked between 2 and 3 weeks after SE and paralleled the development of cognitive impairments, suggesting a role for reactive microglia in this pathophysiology. Microglial survival and proliferation are regulated by the colony-stimulating factor 1 receptor (CSF1R). The CSF1R inhibitor PLX3397 has been shown to reduce/deplete microglial populations and improve cognitive performance in models of neurodegenerative disorders. Therefore, we hypothesized that suppression of microgliosis with PLX3397 during epileptogenesis may attenuate the hippocampal-dependent spatial learning and memory deficits in the rat pilocarpine model of SE and acquired TLE. Different groups of control and SE rats were fed standard chow (SC) or chow with PLX3397 starting immediately after SE and for 3 weeks. Novel object recognition (NOR) and Barnes maze (BM) were performed to determine memory function between 2 and 3 weeks after SE. Then microglial populations were assessed using immunohistochemistry. Control rats fed with either SC or PLX3397 performed similarly in both NOR and BM tests, differentiating novel vs. familiar objects in NOR, and rapidly learning the location of the hidden platform in BM. In contrast, both SE groups (SC and PLX3397) showed significant deficits in both NOR and BM tests compared to controls. Both PLX3397-treated control and SE groups had significantly decreased numbers of microglia in the hippocampus (60%) compared to those in SC. In parallel, we found that PLX3397 treatment also reduced SE-induced hippocampal astrogliosis. Thus, despite drastic reductions in microglial cells, memory was unaffected in the PLX3397-treated groups compared to those in SC, suggesting that remaining microglia may be sufficient to help maintain hippocampal functions. In sum, PLX3397 did not improve or worsen the memory deficits in rats that sustained pilocarpine-induced SE. Further research is required to determine whether microglia play a role in cognitive decline during epileptogenesis.
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Affiliation(s)
- Season K Wyatt-Johnson
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
| | - Alexandra L Sommer
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
| | - Kevin Y Shim
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
| | - Amy L Brewster
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States.,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
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10
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McGregor BA, Schommer J, Guo K, Raihan MO, Ghribi O, Hur J, Porter JE. Alpha-Synuclein-induced DNA Methylation and Gene Expression in Microglia. Neuroscience 2021; 468:186-198. [PMID: 34082066 DOI: 10.1016/j.neuroscience.2021.05.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 12/18/2022]
Abstract
Synucleinopathy disorders are characterized by aggregates of α-synuclein (α-syn), which engage microglia to elicit a neuroinflammatory response. Here, we determined the gene expression and DNA methylation changes in microglia induced by aggregate α-syn. Transgenic murine Thy-1 promoter (mThy1)-Asyn mice overexpressing human α-syn are a model of synucleinopathy. Microglia from 3 and 13-month-old mice were used to isolate nucleic acids for methylated DNA and RNA-sequencing. α-Syn-regulated changes in gene expression and genomic methylation were determined and examined for functional enrichment followed by network analysis to further elucidate possible connections within the data. Microglial DNA isolated from our 3-month cohort had 5315 differentially methylated gene (DMG) changes, while RNA levels demonstrated a change in 119 differentially expressed genes (DEGs) between mThy1-Asyn mice and wild-type littermate controls. The 3-month DEGs and DMGs were highly associated with adhesion and migration signaling, suggesting a phenotypic transition from resting to active microglia. We observed 3742 DMGs and 3766 DEGs in 13-month mThy1-Asyn mice. These genes were often related to adhesion, migration, cell cycle, cellular metabolism, and immune response. Network analysis also showed increased cell mobility and inflammatory functions at 3 months, shifting to cell cycle, immune response, and metabolism changes at 13 months. We observed significant α-syn-induced methylation and gene expression changes in microglia. Our data suggest that α-syn overexpression initiates microglial activation leading to neuroinflammation and cellular metabolic stresses, which is associated with disease progression.
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Affiliation(s)
- Brett A McGregor
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - Jared Schommer
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - Kai Guo
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - Md Obayed Raihan
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - Othman Ghribi
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - Junguk Hur
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA.
| | - James E Porter
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA.
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11
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Yang S, Yang Y, Wang F, Luo Q, Zhang Y, Zheng F, Shu Q, Chen Q, Fang X. TREM2 Dictates Antibacterial Defense and Viability of Bone Marrow-derived Macrophages during Bacterial Infection. Am J Respir Cell Mol Biol 2021; 65:176-188. [PMID: 33848212 DOI: 10.1165/rcmb.2020-0521oc] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Macrophages undergo profound metabolic reprogramming to join key immunoregulatory functions, which can be initiated by pattern recognition receptors. TREM2 (triggering receptor expressed on myeloid cells 2), a macrophage phagocytic receptor, plays pivotal roles in sepsis by enhancing bacterial clearance, which is associated with regulation of reactive oxygen species (ROS) production. However, how intracellular ROS participate in TREM2-mediated bactericidal activity remains unclear. This study was designed to investigate the organelle source and biological activity of ROS in the context of TREM2-mediated immune defense during Escherichia coli infection. Bone marrow-derived macrophages (BMDMs) were transfected with TREM2-overexpressing adenoviruses or control viruses and challenged with E. coli. The BMDMs were administered to mouse models with local E. coli infection. In addition, monocytic TREM2 expression, NOX2 concentrations, and pyroptosis were detected in patients with bacterial sepsis. General ROS production was found to be comparable between TREM2-overexpressing and control BMDMs upon E. coli challenge. The deficiency of Nox2 led to impaired phagosome degradation and lack of bactericidal ability and abolished TREM2-mediated protective activity against pulmonary E. coli infection. Overexpression of TREM2 suppressed mitochondrial ROS generation, inhibited NLRP3/caspase-1 inflammasome activation, and finally protected BMDMs from gasdermin D-mediated pyroptosis during pulmonary E. coli infection. The protective role of TREM2 was further confirmed in mice with abdominal E. coli infection. Moreover, monocytic TREM2 expression was positively correlated with NOX2 concentrations and negatively correlated with pyroptosis and disease severity in patients with bacterial sepsis. Collectively, TREM2 controls macrophage immune functions by fine-tuning ROS generation and enhances the host defense against bacterial infection. Our data suggest that TREM2 is a promising candidate target for sepsis therapy.
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Affiliation(s)
- ShiYue Yang
- Department of Anesthesiology and Intensive Care, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; and
| | - Yang Yang
- Department of Anesthesiology and Intensive Care, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; and
| | - FeiFei Wang
- Department of Anesthesiology and Intensive Care, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; and
| | - QinYu Luo
- Department of Clinical Research Center, The Children's Hospital, School of Medicine, Zhejiang University, National Clinical Research Center for Child Health, Hangzhou, China
| | - Yan Zhang
- Department of Clinical Research Center, The Children's Hospital, School of Medicine, Zhejiang University, National Clinical Research Center for Child Health, Hangzhou, China
| | - Fei Zheng
- Department of Clinical Research Center, The Children's Hospital, School of Medicine, Zhejiang University, National Clinical Research Center for Child Health, Hangzhou, China
| | - Qiang Shu
- Department of Clinical Research Center, The Children's Hospital, School of Medicine, Zhejiang University, National Clinical Research Center for Child Health, Hangzhou, China
| | - QiXing Chen
- Department of Clinical Research Center, The Children's Hospital, School of Medicine, Zhejiang University, National Clinical Research Center for Child Health, Hangzhou, China
| | - XiangMing Fang
- Department of Anesthesiology and Intensive Care, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China; and
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12
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Marzan DE, Brügger-Verdon V, West BL, Liddelow S, Samanta J, Salzer JL. Activated microglia drive demyelination via CSF1R signaling. Glia 2021; 69:1583-1604. [PMID: 33620118 DOI: 10.1002/glia.23980] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 02/06/2023]
Abstract
Microgliosis is a prominent pathological feature in many neurological diseases including multiple sclerosis (MS), a progressive auto-immune demyelinating disorder. The precise role of microglia, parenchymal central nervous system (CNS) macrophages, during demyelination, and the relative contributions of peripheral macrophages are incompletely understood. Classical markers used to identify microglia do not reliably discriminate between microglia and peripheral macrophages, confounding analyses. Here, we use a genetic fate mapping strategy to identify microglia as predominant responders and key effectors of demyelination in the cuprizone (CUP) model. Colony-stimulating factor 1 (CSF1), also known as macrophage colony-stimulating factor (M-CSF) - a secreted cytokine that regulates microglia development and survival-is upregulated in demyelinated white matter lesions. Depletion of microglia with the CSF1R inhibitor PLX3397 greatly abrogates the demyelination, loss of oligodendrocytes, and reactive astrocytosis that results from CUP treatment. Electron microscopy (EM) and serial block face imaging show myelin sheaths remain intact in CUP treated mice depleted of microglia. However, these CUP-damaged myelin sheaths are lost and robustly phagocytosed upon-repopulation of microglia. Direct injection of CSF1 into CNS white matter induces focal microgliosis and demyelination indicating active CSF1 signaling can promote demyelination. Finally, mice defective in adopting a toxic astrocyte phenotype that is driven by microglia nevertheless demyelinate normally upon CUP treatment implicating microglia rather than astrocytes as the primary drivers of CUP-mediated demyelination. Together, these studies indicate activated microglia are required for and can drive demyelination directly and implicate CSF1 signaling in these events.
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Affiliation(s)
- Dave E Marzan
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU Grossman School of Medicine, New York, New York, USA.,Translational Neuroscience Program, University of Pennsylvania, Philadelphia, PA, USA
| | - Valérie Brügger-Verdon
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU Grossman School of Medicine, New York, New York, USA
| | | | - Shane Liddelow
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU Grossman School of Medicine, New York, New York, USA
| | - Jayshree Samanta
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - James L Salzer
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU Grossman School of Medicine, New York, New York, USA
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13
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Grabowski GA, Antommaria AHM, Kolodny EH, Mistry PK. Gaucher disease: Basic and translational science needs for more complete therapy and management. Mol Genet Metab 2021; 132:59-75. [PMID: 33419694 PMCID: PMC8809485 DOI: 10.1016/j.ymgme.2020.12.291] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/15/2020] [Accepted: 12/18/2020] [Indexed: 12/12/2022]
Affiliation(s)
- Gregory A Grabowski
- Department of Pediatrics, University of Cincinnati College of Medicine, United States of America; Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, United States of America; Division of Human Genetics, Cincinnati Children's Research Foundation, Cincinnati, OH, United States of America.
| | - Armand H M Antommaria
- Department of Pediatrics, University of Cincinnati College of Medicine, United States of America; Lee Ault Carter Chair of Pediatric Ethics, Cincinnati Children's Research Foundation, Cincinnati, OH, United States of America.
| | - Edwin H Kolodny
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States of America.
| | - Pramod K Mistry
- Departments of Medicine and Pediatrics, Yale School of Medicine, New Haven, CT, United States of America.
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14
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Steiner A, Schlepckow K, Brunner B, Steiner H, Haass C, Hagn F. γ-Secretase cleavage of the Alzheimer risk factor TREM2 is determined by its intrinsic structural dynamics. EMBO J 2020; 39:e104247. [PMID: 32830336 PMCID: PMC7560206 DOI: 10.15252/embj.2019104247] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 12/14/2022] Open
Abstract
Sequence variants of the microglial expressed TREM2 (triggering receptor expressed on myeloid cells 2) are a major risk factor for late onset Alzheimer's disease. TREM2 requires a stable interaction with DAP12 in the membrane to initiate signaling, which is terminated by TREM2 ectodomain shedding and subsequent intramembrane cleavage by γ‐secretase. To understand the structural basis for the specificity of the intramembrane cleavage event, we determined the solution structure of the TREM2 transmembrane helix (TMH). Caused by the presence of a charged amino acid in the membrane region, the TREM2‐TMH adopts a kinked structure with increased flexibility. Charge removal leads to TMH stabilization and reduced dynamics, similar to its structure in complex with DAP12. Strikingly, these dynamical features match with the site of the initial γ‐secretase cleavage event. These data suggest an unprecedented cleavage mechanism by γ‐secretase where flexible TMH regions act as key determinants of substrate cleavage specificity.
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Affiliation(s)
- Andrea Steiner
- Bavarian NMR Center at the Department of Chemistry and Institute for Advanced Study, Technical University of Munich, Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Kai Schlepckow
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Bettina Brunner
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Harald Steiner
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Biomedical Center (BMC), Chair of Metabolic Biochemistry, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Christian Haass
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Biomedical Center (BMC), Chair of Metabolic Biochemistry, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Franz Hagn
- Bavarian NMR Center at the Department of Chemistry and Institute for Advanced Study, Technical University of Munich, Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany
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15
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Ren S, Yao W, Tambini MD, Yin T, Norris KA, D'Adamio L. Microglia TREM2R47H Alzheimer-linked variant enhances excitatory transmission and reduces LTP via increased TNF-α levels. eLife 2020; 9:57513. [PMID: 32579116 PMCID: PMC7338048 DOI: 10.7554/elife.57513] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 06/23/2020] [Indexed: 01/09/2023] Open
Abstract
To study the mechanisms by which the p.R47H variant of the microglia gene and Alzheimer’s disease (AD) risk factor TREM2 increases dementia risk, we created Trem2R47H KI rats. Trem2R47H rats were engineered to produce human Aβ to define human-Aβ-dependent and -independent pathogenic mechanisms triggered by this variant. Interestingly, pre- and peri-adolescent Trem2R47H rats present increased brain concentrations of TNF-α, augmented glutamatergic transmission, suppression of Long-term-Potentiation (LTP), an electrophysiological surrogate of learning and memory, but normal Aβ levels. Acute reduction of TNF-α activity with a neutralizing anti-TNF-α antibody occludes the boost in amplitude of glutamatergic transmission and LTP suppression observed in young Trem2R47H/R47H rats. Thus, the microglia-specific pathogenic Trem2 variant boosts glutamatergic neuronal transmission and suppresses LTP by increasing brain TNF-α concentrations, directly linking microglia to neuronal dysfunction. Future studies will determine whether this phenomenon represents an early, Aβ-independent pathway that facilitates dementia pathogenesis in humans.
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Affiliation(s)
- Siqiang Ren
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Wen Yao
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Marc D Tambini
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Tao Yin
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Kelly A Norris
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Luciano D'Adamio
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
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16
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Cable J, Holtzman DM, Hyman BT, Tansey MG, Colonna M, Kellis M, Brinton RD, Albert M, Wellington CL, Sisodia SS, Tanzi RE. Alternatives to amyloid for Alzheimer's disease therapies-a symposium report. Ann N Y Acad Sci 2020; 1475:3-14. [PMID: 32472577 DOI: 10.1111/nyas.14371] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 04/22/2020] [Indexed: 12/13/2022]
Abstract
For decades, Alzheimer's disease research has focused on amyloid as the primary pathogenic agent. This focus has driven the development of numerous amyloid-targeting therapies; however, with one possible exception, none of these therapies have been effective in preventing or delaying cognitive decline in patients, and there are no approved disease-modifying agents. It is becoming more apparent that alternative drug targets are needed to address this complex disease. An increased understanding of Alzheimer's disease pathology has highlighted the need to target the appropriate disease pathology at the appropriate time in the disease course. Preclinical and early clinical studies have focused on targets, including inflammation, tau, vascular health, and the microbiome. This report summarizes the presentations from a New York Academy of Sciences' one-day symposium entitled "Alzheimer's Disease Therapeutics: Alternatives to Amyloid," held on November 20, 2019.
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Affiliation(s)
| | - David M Holtzman
- Department of Neurology, Washington University in St. Louis, St. Louis, Missouri
| | - Bradley T Hyman
- Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Malú Gámez Tansey
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, University of Florida College of Medicine, McKnight Brain Institute, Gainesville, Florida
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
| | - Manolis Kellis
- MIT Computer Science and Artificial Intelligence Laboratory, Cambridge, Massachusetts.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Roberta D Brinton
- Departments of Pharmacology and Neurology, College of Medicine, the University of Arizona, Tucson, Arizona
| | - Marilyn Albert
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Cheryl L Wellington
- Department of Pathology and Laboratory Medicine, Djavad Mowafaghian Centre for Brain Health, International Collaboration on Repair Discoveries, School of Biomedical Engineering, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sangram S Sisodia
- Department of Neurobiology, the University of Chicago, Chicago, Illinois.,The Microbiome Center, the University of Chicago, Chicago, Illinois
| | - Rudolph E Tanzi
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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17
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Schlepckow K, Monroe KM, Kleinberger G, Cantuti‐Castelvetri L, Parhizkar S, Xia D, Willem M, Werner G, Pettkus N, Brunner B, Sülzen A, Nuscher B, Hampel H, Xiang X, Feederle R, Tahirovic S, Park JI, Prorok R, Mahon C, Liang C, Shi J, Kim DJ, Sabelström H, Huang F, Di Paolo G, Simons M, Lewcock JW, Haass C. Enhancing protective microglial activities with a dual function TREM2 antibody to the stalk region. EMBO Mol Med 2020; 12:e11227. [PMID: 32154671 PMCID: PMC7136959 DOI: 10.15252/emmm.201911227] [Citation(s) in RCA: 147] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 02/12/2020] [Accepted: 02/17/2020] [Indexed: 01/07/2023] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2) is essential for the transition of homeostatic microglia to a disease-associated microglial state. To enhance TREM2 activity, we sought to selectively increase the full-length protein on the cell surface via reducing its proteolytic shedding by A Disintegrin And Metalloproteinase (i.e., α-secretase) 10/17. We screened a panel of monoclonal antibodies against TREM2, with the aim to selectively compete for α-secretase-mediated shedding. Monoclonal antibody 4D9, which has a stalk region epitope close to the cleavage site, demonstrated dual mechanisms of action by stabilizing TREM2 on the cell surface and reducing its shedding, and concomitantly activating phospho-SYK signaling. 4D9 stimulated survival of macrophages and increased microglial uptake of myelin debris and amyloid β-peptide in vitro. In vivo target engagement was demonstrated in cerebrospinal fluid, where nearly all soluble TREM2 was 4D9-bound. Moreover, in a mouse model for Alzheimer's disease-related pathology, 4D9 reduced amyloidogenesis, enhanced microglial TREM2 expression, and reduced a homeostatic marker, suggesting a protective function by driving microglia toward a disease-associated state.
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Affiliation(s)
- Kai Schlepckow
- German Center for Neurodegenerative Diseases (DZNE) MunichMunichGermany
| | | | - Gernot Kleinberger
- Metabolic BiochemistryBiomedical Center (BMC)Faculty of MedicineLudwig‐Maximilians‐Universität MünchenMunichGermany
- Present address:
ISAR Bioscience GmbHPlaneggGermany
| | | | - Samira Parhizkar
- Metabolic BiochemistryBiomedical Center (BMC)Faculty of MedicineLudwig‐Maximilians‐Universität MünchenMunichGermany
| | - Dan Xia
- Denali Therapeutics Inc.South San FranciscoCAUSA
| | - Michael Willem
- Metabolic BiochemistryBiomedical Center (BMC)Faculty of MedicineLudwig‐Maximilians‐Universität MünchenMunichGermany
| | - Georg Werner
- Metabolic BiochemistryBiomedical Center (BMC)Faculty of MedicineLudwig‐Maximilians‐Universität MünchenMunichGermany
| | - Nadine Pettkus
- Metabolic BiochemistryBiomedical Center (BMC)Faculty of MedicineLudwig‐Maximilians‐Universität MünchenMunichGermany
| | - Bettina Brunner
- German Center for Neurodegenerative Diseases (DZNE) MunichMunichGermany
| | - Alice Sülzen
- German Center for Neurodegenerative Diseases (DZNE) MunichMunichGermany
| | - Brigitte Nuscher
- Metabolic BiochemistryBiomedical Center (BMC)Faculty of MedicineLudwig‐Maximilians‐Universität MünchenMunichGermany
| | - Heike Hampel
- Metabolic BiochemistryBiomedical Center (BMC)Faculty of MedicineLudwig‐Maximilians‐Universität MünchenMunichGermany
| | - Xianyuan Xiang
- Metabolic BiochemistryBiomedical Center (BMC)Faculty of MedicineLudwig‐Maximilians‐Universität MünchenMunichGermany
- Graduate School of Systemic NeuroscienceLudwig‐Maximilians‐Universität MünchenMunichGermany
| | - Regina Feederle
- German Center for Neurodegenerative Diseases (DZNE) MunichMunichGermany
- Munich Cluster for Systems Neurology (SyNergy)MunichGermany
- Helmholtz Center MunichGerman Research Center for Environmental HealthInstitute for Diabetes and ObesityCore Facility Monoclonal Antibody DevelopmentMunichGermany
| | - Sabina Tahirovic
- German Center for Neurodegenerative Diseases (DZNE) MunichMunichGermany
| | | | | | - Cathal Mahon
- Denali Therapeutics Inc.South San FranciscoCAUSA
| | | | - Ju Shi
- Denali Therapeutics Inc.South San FranciscoCAUSA
- Present address:
Jazz PharmaceuticalsPalo AltoCAUSA
| | - Do Jin Kim
- Denali Therapeutics Inc.South San FranciscoCAUSA
| | | | - Fen Huang
- Denali Therapeutics Inc.South San FranciscoCAUSA
| | | | - Mikael Simons
- German Center for Neurodegenerative Diseases (DZNE) MunichMunichGermany
- Munich Cluster for Systems Neurology (SyNergy)MunichGermany
- Institute of Neuronal Cell Biology (TUM‐NZB)MunichGermany
| | | | - Christian Haass
- German Center for Neurodegenerative Diseases (DZNE) MunichMunichGermany
- Metabolic BiochemistryBiomedical Center (BMC)Faculty of MedicineLudwig‐Maximilians‐Universität MünchenMunichGermany
- Munich Cluster for Systems Neurology (SyNergy)MunichGermany
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18
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Pedicone C, Fernandes S, Dungan OM, Dormann SM, Viernes DR, Adhikari AA, Choi LB, De Jong EP, Chisholm JD, Kerr WG. Pan-SHIP1/2 inhibitors promote microglia effector functions essential for CNS homeostasis. J Cell Sci 2020; 133:jcs238030. [PMID: 31780579 PMCID: PMC10682645 DOI: 10.1242/jcs.238030] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/21/2019] [Indexed: 12/11/2022] Open
Abstract
We show here that both SHIP1 (Inpp5d) and its paralog SHIP2 (Inppl1) are expressed at protein level in microglia. To examine whether targeting of SHIP paralogs might influence microglial physiology and function, we tested the capacity of SHIP1-selective, SHIP2-selective and pan-SHIP1/2 inhibitors for their ability to impact on microglia proliferation, lysosomal compartment size and phagocytic function. We find that highly potent pan-SHIP1/2 inhibitors can significantly increase lysosomal compartment size, and phagocytosis of dead neurons and amyloid beta (Aβ)1-42 by microglia in vitro We show that one of the more-potent and water-soluble pan-SHIP1/2 inhibitors, K161, can penetrate the blood-brain barrier. Consistent with this, K161 increases the capacity of CNS-resident microglia to phagocytose Aβ and apoptotic neurons following systemic administration. These findings provide the first demonstration that small molecule modulation of microglia function in vivo is feasible, and suggest that dual inhibition of the SHIP1 and 2 paralogs can provide a novel means to enhance basal microglial homeostatic functions for therapeutic purposes in Alzheimer's disease and, possibly, other types of dementia where increased microglial function could be beneficial.
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Affiliation(s)
- Chiara Pedicone
- Department of Microbiology & Immunology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Sandra Fernandes
- Department of Microbiology & Immunology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Otto M Dungan
- Department of Chemistry, Syracuse University, Syracuse, NY 13210, USA
| | - Shawn M Dormann
- Department of Chemistry, Syracuse University, Syracuse, NY 13210, USA
| | - Dennis R Viernes
- Department of Chemistry, Syracuse University, Syracuse, NY 13210, USA
| | - Arijit A Adhikari
- Department of Chemistry, Syracuse University, Syracuse, NY 13210, USA
| | - Lydia B Choi
- Department of Chemistry, Syracuse University, Syracuse, NY 13210, USA
| | - Ebbing P De Jong
- Proteomics and Mass Spectrometry Core Facility, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - John D Chisholm
- Department of Chemistry, Syracuse University, Syracuse, NY 13210, USA
| | - William G Kerr
- Department of Microbiology & Immunology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- Department of Chemistry, Syracuse University, Syracuse, NY 13210, USA
- Department of Pediatrics, SUNY Upstate Medical University, Syracuse, NY 13210, USA
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19
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Abstract
Microglia are the resident immune cells and professional phagocytes of the central nervous system. However, little is known about the contribution of their phagocytic signaling to the neuropathology and pathophysiology of epilepsy. Here, we summarize and discuss the implications of recent evidence supporting that aberrant microglia phagocytic activity and alterations in phagocytosis signaling molecules occur in association with microglia-neuronal contacts, neuronal/synaptic loss, and spontaneous recurrent seizures in human and preclinical models of epilepsy. This body of evidence provides strong support that the microglial contribution to epileptogenic networks goes beyond inflammation, and suggests that phagocytic signaling molecules may be novel therapeutic targets for epilepsy.
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Affiliation(s)
| | - Amy L. Brewster
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, USA
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20
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Functional microglia neurotransmitters in amyotrophic lateral sclerosis. Semin Cell Dev Biol 2019; 94:121-128. [PMID: 31009755 DOI: 10.1016/j.semcdb.2019.04.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 04/18/2019] [Accepted: 04/18/2019] [Indexed: 12/13/2022]
Abstract
Today neuroscience is dominated by the perspective that microglia are essential elements in any integrated view of the nervous system. A number of different neuroinflammatory conditions affect the CNS where microglia involvement, and particularly microgliosis, is not only a prominent feature, but also a pathogenic key mechanism of disease. On the other side, microglia can also constitute an important trigger of neuronal protection during neurodegenerative disorders. For instance in ALS and other motor neuron diseases, available evidence suggests the coexistence of quite different roles for microglia, characterized by neuroprotective functions at early stages, and neurotoxic actions during disease progression. The scope of this review is a brief discussion about microglia being activated and functioning during ALS, and particularly about neurotransmitters participating to the pathological signature of ALS microglia. We will discuss that ALS microglia can express a variety of classical neurotransmitter receptors comprising those for extracellular ATP, glutamate and histamine. We will review data indicating that the modulation of these transmitter receptors may induce beneficial effects in ALS models, so that the protective properties of microglia can be emphasized at the expenses of their toxicity.
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21
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Norris GT, Kipnis J. Immune cells and CNS physiology: Microglia and beyond. J Exp Med 2018; 216:60-70. [PMID: 30504438 PMCID: PMC6314530 DOI: 10.1084/jem.20180199] [Citation(s) in RCA: 151] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 08/15/2018] [Accepted: 11/13/2018] [Indexed: 12/25/2022] Open
Abstract
In recent years, there has been great progress in the field of neuroimmunology, implicating both parenchymal macrophages (microglia) and meningeal immunity in homeostatic brain function. In this review, Norris and Kipnis discuss these two immune compartments and how they are critically segregated to preserve homoeostasis. Recent advances have directed our knowledge of the immune system from a narrative of “self” versus “nonself” to one in which immune function is critical for homeostasis of organs throughout the body. This is also the case with respect to the central nervous system (CNS). CNS immunity exists in a segregated state, with a marked partition occurring between the brain parenchyma and meningeal spaces. While the brain parenchyma is patrolled by perivascular macrophages and microglia, the meningeal spaces are supplied with a diverse immune repertoire. In this review, we posit that such partition allows for neuro–immune crosstalk to be properly tuned. Convention may imply that meningeal immunity is an ominous threat to brain function; however, recent studies have shown that its presence may instead be a steady hand directing the CNS to optimal performance.
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Affiliation(s)
- Geoffrey T Norris
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA .,Department of Neuroscience, University of Virginia, Charlottesville, VA.,Neuroscience Graduate Program, University of Virginia, Charlottesville, VA
| | - Jonathan Kipnis
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA .,Department of Neuroscience, University of Virginia, Charlottesville, VA.,Neuroscience Graduate Program, University of Virginia, Charlottesville, VA
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22
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Zheng H, Cheng B, Li Y, Li X, Chen X, Zhang YW. TREM2 in Alzheimer's Disease: Microglial Survival and Energy Metabolism. Front Aging Neurosci 2018; 10:395. [PMID: 30532704 PMCID: PMC6265312 DOI: 10.3389/fnagi.2018.00395] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 11/13/2018] [Indexed: 12/16/2022] Open
Abstract
Alzheimer’s disease (AD) is the leading cause of age-related dementia among the elderly population. Recent genetic studies have identified rare variants of the gene encoding the triggering receptor expressed on myeloid cells-2 (TREM2) as significant genetic risk factors in late-onset AD (LOAD). TREM2 is specifically expressed in brain microglia and modulates microglial functions in response to key AD pathologies such as amyloid-β (Aβ) plaques and tau tangles. In this review article, we discuss recent research progress in our understanding on the role of TREM2 in microglia and its relevance to AD pathologies. In addition, we discuss evidence describing new TREM2 ligands and the role of TREM2 signaling in microglial survival and energy metabolism. A comprehensive understanding of TREM2 function in the pathogenesis of AD offers a unique opportunity to explore the potential of this microglial receptor as an alternative target in AD therapy.
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Affiliation(s)
- Honghua Zheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China.,Shenzhen Research Institute, Xiamen University, Shenzhen, China
| | - Baoying Cheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China
| | - Yanfang Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China.,Shenzhen Research Institute, Xiamen University, Shenzhen, China
| | - Xin Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China
| | - Xiaofen Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China.,Shenzhen Research Institute, Xiamen University, Shenzhen, China
| | - Yun-Wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China
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23
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Jackson TC, Kotermanski SE, Kochanek PM, Jackson EK. Oxidative stress induces release of 2'-AMP from microglia. Brain Res 2018; 1706:101-109. [PMID: 30395838 DOI: 10.1016/j.brainres.2018.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 10/31/2018] [Accepted: 11/02/2018] [Indexed: 11/18/2022]
Abstract
BACKGROUND Microglia metabolize exogenous 2'-AMP and 3'-AMP (non-canonical nucleotides) to adenosine and exogenous 2'-AMP and 3'-AMP (via conversion to adenosine) inhibit the production of inflammatory cytokines by microglia. This suggests that if microglia release endogenous 2'-AMP and/or 3'-AMP in response to injurious stimuli, this would complete an autocrine/paracrine mechanism that attenuates the over-activation of microglia during brain injury. Here we investigated in microglia (and for comparison astrocytes and neurons) the effects of injurious stimuli on extracellular and intracellular levels of 2',3'-cAMP (2'-AMP and 3'-AMP precursor), 2'-AMP, and 3'-AMP. METHODS Experiments were conducted in primary cultures of rat microglia, astrocytes, and neurons. Cells were exposed to oxygen/glucose deprivation, iodoacetate plus 2,4-dinitrophenol (metabolic inhibitors), glutamate, or H2O2 for one hour, and extracellular and intracellular 2',3'-cAMP, 2'-AMP, and 3'-AMP were measured by UPLC-MS/MS. KEY RESULTS In microglia, H2O2 increased extracellular levels of 2'-AMP, but not 3'-AMP, by ∼16-fold (from 0.17 ± 0.11 to 2.78 ± 0.27 ng/106 cells; n = 13; mean ± SEM; P < 0.000005). H2O2 also induced oxidative changes in cellular proteins as detected by an increased number of carbonyl groups in protein side chains. In contrast, oxygen/glucose deprivation, metabolic inhibitors, or glutamate had no effect on either extracellular 2'-AMP or 3'-AMP levels. In astrocytes and neurons, none of the injurious stimuli increased extracellular 2'-AMP or 3'-AMP. CONCLUSIONS Oxidative stress (but not oxygen/glucose deprivation, energy deprivation, or excitotoxicity) induces microglia (but not astrocytes or neurons) to release 2'-AMP, but not 3'-AMP. The 2',3'-cAMP/2'-AMP/adenosine pathway mechanism may serve to prevent over-activation of microglia in response to oxidative stress.
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Affiliation(s)
- Travis C Jackson
- Department of Critical Care Medicine, Children's Hospital of Pittsburgh, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Shawn E Kotermanski
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Patrick M Kochanek
- Department of Critical Care Medicine, Children's Hospital of Pittsburgh, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Edwin K Jackson
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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24
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Hoye ML, Archambault AS, Gordon TM, Oetjen LK, Cain MD, Klein RS, Crosby SD, Kim BS, Miller TM, Wu GF. MicroRNA signature of central nervous system-infiltrating dendritic cells in an animal model of multiple sclerosis. Immunology 2018; 155:112-122. [PMID: 29749614 PMCID: PMC6099169 DOI: 10.1111/imm.12934] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 02/28/2018] [Accepted: 03/23/2018] [Indexed: 12/11/2022] Open
Abstract
Innate immune cells are integral to the pathogenesis of several diseases of the central nervous system (CNS), including multiple sclerosis (MS). Dendritic cells (DCs) are potent CD11c+ antigen-presenting cells that are critical regulators of adaptive immune responses, particularly in autoimmune diseases such as MS. The regulation of DC function in both the periphery and CNS compartment has not been fully elucidated. One limitation to studying the role of CD11c+ DCs in the CNS is that microglia can upregulate CD11c during inflammation, making it challenging to distinguish bone marrow-derived DCs (BMDCs) from microglia. Selective expression of microRNAs (miRNAs) has been shown to distinguish populations of innate cells and regulate their function within the CNS during neuro-inflammation. Using the experimental autoimmune encephalomyelitis (EAE) murine model of MS, we characterized the expression of miRNAs in CD11c+ cells using a non-biased murine array. Several miRNAs, including miR-31, were enriched in CD11c+ cells within the CNS during EAE, but not LysM+ microglia. Moreover, to distinguish CD11c+ DCs from microglia that upregulate CD11c, we generated bone marrow chimeras and found that miR-31 expression was specific to BMDCs. Interestingly, miR-31-binding sites were enriched in mRNAs downregulated in BMDCs that migrated into the CNS, and a subset was confirmed to be regulated by miR-31. Finally, miR-31 was elevated in DCs migrating through an in vitro blood-brain barrier. Our findings suggest miRNAs, including miR-31, may regulate entry of DCs into the CNS during EAE, and could potentially represent therapeutic targets for CNS autoimmune diseases such as MS.
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Affiliation(s)
- Mariah L. Hoye
- Department of NeurologyWashington University School of MedicineSt LouisMOUSA
| | | | - Taylor M. Gordon
- Department of NeurologyWashington University School of MedicineSt LouisMOUSA
| | - Landon K. Oetjen
- Department of MedicineWashington University School of MedicineSt LouisMOUSA
| | - Matthew D. Cain
- Department of MedicineWashington University School of MedicineSt LouisMOUSA
| | - Robyn S. Klein
- Department of MedicineWashington University School of MedicineSt LouisMOUSA
- The Hope Center for Neurological DisordersWashington University School of MedicineSt LouisMOUSA
| | - Seth D. Crosby
- Genome Technology Access CenterWashington University School of MedicineSt LouisMOUSA
| | - Brian S. Kim
- Department of MedicineWashington University School of MedicineSt LouisMOUSA
- Department of Immunology & PathologyWashington University School of MedicineSt LouisMOUSA
- Center for the Study of ItchWashington University School of MedicineSt LouisMOUSA
| | - Timothy M. Miller
- Department of NeurologyWashington University School of MedicineSt LouisMOUSA
- The Hope Center for Neurological DisordersWashington University School of MedicineSt LouisMOUSA
| | - Gregory F. Wu
- Department of NeurologyWashington University School of MedicineSt LouisMOUSA
- The Hope Center for Neurological DisordersWashington University School of MedicineSt LouisMOUSA
- Department of Immunology & PathologyWashington University School of MedicineSt LouisMOUSA
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25
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Heuss ND, Pierson MJ, Roehrich H, McPherson SW, Gram AL, Li L, Gregerson DS. Optic nerve as a source of activated retinal microglia post-injury. Acta Neuropathol Commun 2018; 6:66. [PMID: 30037353 PMCID: PMC6055350 DOI: 10.1186/s40478-018-0571-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 07/15/2018] [Indexed: 12/27/2022] Open
Abstract
Using mice expressing green fluorescent protein (GFP) from a transgenic CD11c promoter we found that a controlled optic nerve crush (ONC) injury attracted GFPhi retinal myeloid cells to the dying retinal ganglion cells and their axons. However, the origin of these retinal myeloid cells was uncertain. In this study we use transgenic mice in conjunction with ONC, partial and full optic nerve transection (ONT), and parabiosis to determine the origin of injury induced retinal myeloid cells. Analysis of parabiotic mice and fate mapping showed that responding retinal myeloid cells were not derived from circulating macrophages and that GFPhi myeloid cells could be derived from GFPlo microglia. Comparison of optic nerve to retina following an ONC showed a much greater concentration of GFPhi cells and GFPlo microglia in the optic nerve. Optic nerve injury also induced Ki67+ cells in the optic nerve but not in the retina. Comparison of the retinal myeloid cell response after full versus partial ONT revealed fewer GFPhi cells and GFPlo microglia in the retina following a full ONT despite it being a more severe injury, suggesting that full transection of the optic nerve can block the migration of responding myeloid cells to the retina. Our results suggest that the optic nerve can be a reservoir for activated microglia and other retinal myeloid cells in the retina following optic nerve injury.
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26
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Norris GT, Smirnov I, Filiano AJ, Shadowen HM, Cody KR, Thompson JA, Harris TH, Gaultier A, Overall CC, Kipnis J. Neuronal integrity and complement control synaptic material clearance by microglia after CNS injury. J Exp Med 2018; 215:1789-1801. [PMID: 29941548 PMCID: PMC6028515 DOI: 10.1084/jem.20172244] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 03/20/2018] [Accepted: 05/09/2018] [Indexed: 01/18/2023] Open
Abstract
Norris et al. show that microglia are the key phagocytes in removal of synaptic debris in the dorsal lateral geniculate nucleus after optic nerve injury. This microglial function is dependent on recognition of neurodegeneration and is mediated by the complement system. Phagocytosis of synaptic material by microglia is critical for central nervous system development. Less well understood is this microglial function in the injured adult brain. Assay of microglial phagocytosis is challenging, because peripheral myeloid cells engraft the site of injury, which could obscure interpretation of microglial roles. The model used here, optic nerve crush injury, results in degeneration of synapses in the dorsal lateral geniculate nucleus (dLGN), which stimulates rapid activation and engulfment of synaptic material by resident microglia without myeloid cell engraftment. Pharmacological depletion of microglia causes postinjury accumulation of synaptic debris, suggesting that microglia are the dominant postinjury phagocytes. Genetic or pharmacological manipulations revealed that neuronal activity does not trigger microglia phagocytosis after injury. RNA sequencing reveals C1q and CD11b/CR3 involvement in clearance of debris by dLGN-resident microglia. Indeed, C1qa−/− and Itgam−/− mice exhibit impaired postinjury debris clearance. Our results show how neurodegenerative debris is cleared by microglia and offers a model for studying its mechanisms and physiological roles.
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Affiliation(s)
- Geoffrey T Norris
- Center for Brain Immunology, and Glia (BIG), University of Virginia, Charlottesville, VA.,Department of Neuroscience, University of Virginia, Charlottesville, VA.,Neuroscience Graduate Program, University of Virginia, Charlottesville, VA
| | - Igor Smirnov
- Center for Brain Immunology, and Glia (BIG), University of Virginia, Charlottesville, VA.,Department of Neuroscience, University of Virginia, Charlottesville, VA
| | - Anthony J Filiano
- Center for Brain Immunology, and Glia (BIG), University of Virginia, Charlottesville, VA.,Department of Neuroscience, University of Virginia, Charlottesville, VA
| | - Hannah M Shadowen
- Center for Brain Immunology, and Glia (BIG), University of Virginia, Charlottesville, VA.,Department of Neuroscience, University of Virginia, Charlottesville, VA
| | - Kris R Cody
- Center for Brain Immunology, and Glia (BIG), University of Virginia, Charlottesville, VA.,Department of Neuroscience, University of Virginia, Charlottesville, VA
| | - Jeremy A Thompson
- Center for Brain Immunology, and Glia (BIG), University of Virginia, Charlottesville, VA.,Department of Neuroscience, University of Virginia, Charlottesville, VA.,Neuroscience Graduate Program, University of Virginia, Charlottesville, VA
| | - Tajie H Harris
- Center for Brain Immunology, and Glia (BIG), University of Virginia, Charlottesville, VA.,Department of Neuroscience, University of Virginia, Charlottesville, VA.,Neuroscience Graduate Program, University of Virginia, Charlottesville, VA
| | - Alban Gaultier
- Center for Brain Immunology, and Glia (BIG), University of Virginia, Charlottesville, VA.,Department of Neuroscience, University of Virginia, Charlottesville, VA.,Neuroscience Graduate Program, University of Virginia, Charlottesville, VA
| | - Christopher C Overall
- Center for Brain Immunology, and Glia (BIG), University of Virginia, Charlottesville, VA.,Department of Neuroscience, University of Virginia, Charlottesville, VA
| | - Jonathan Kipnis
- Center for Brain Immunology, and Glia (BIG), University of Virginia, Charlottesville, VA .,Department of Neuroscience, University of Virginia, Charlottesville, VA.,Neuroscience Graduate Program, University of Virginia, Charlottesville, VA
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27
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Vanderwall AG, Noor S, Sun MS, Sanchez JE, Yang XO, Jantzie LL, Mellios N, Milligan ED. Effects of spinal non-viral interleukin-10 gene therapy formulated with d-mannose in neuropathic interleukin-10 deficient mice: Behavioral characterization, mRNA and protein analysis in pain relevant tissues. Brain Behav Immun 2018; 69:91-112. [PMID: 29113923 PMCID: PMC5857419 DOI: 10.1016/j.bbi.2017.11.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 10/20/2017] [Accepted: 11/03/2017] [Indexed: 12/17/2022] Open
Abstract
Studies show that spinal (intrathecal; i.t.) interleukin-10 (IL-10) gene therapy reverses neuropathic pain in animal models, and co-administration with the mannose receptor (MR; CD206) ligand d-mannose (DM) greatly improves therapeutic efficacy. However, the actions of endogenous IL-10 may be required for enduring pain control observed following i.t. IL-10 gene therapy, potentially narrowing the application of this non-viral transgene delivery approach. Here, we show that i.t. application of naked plasmid DNA expressing the IL-10 transgene co-injected with DM (DM/pDNA-IL-10) for the treatment of peripheral neuropathic pain in IL-10 deficient (IL-10 KO) mice results in a profound and prolonged bilateral pain suppression. Neuropathic pain is induced by unilateral sciatic chronic constriction injury (CCI), and while enduring relief of light touch sensitivity (mechanical allodynia) in both wild type (WT) and IL-10 KO mice was observed following DM/pDNA-IL-10 co-therapy, transient reversal from allodynia was observed following i.t. DM alone. In stably pain-relieved IL-10 KO mice given DM/pDNA-IL-10, mRNA for the IL-10 transgene is detected in the cauda equina and ipsilateral dorsal root ganglia (DRG), but not the lumbar spinal cord. Further, DM/pDNA-IL-10 application increases anti-inflammatory TGF-β1 and decreases pro-inflammatory TNF mRNA in the ipsilateral DRG compared to allodynic controls. Additionally, DM/pDNA-IL-10 treated mice exhibit decreased spinal pro-inflammatory mRNA expression for TNF, CCL2 (MCP-1), and for the microglial-specific marker TMEM119. Similarly, DM/pDNA-IL-10 treatment decreases immunoreactivity for the astrocyte activation marker GFAP in lumbar spinal cord dorsal horn. Despite transient reversal and early return to allodynia in DM-treated mice, lumbar spinal cord revealed elevated TNF, CCL2 and TMEM119 mRNA levels. Both MR (CD206) and IL-10 receptor mRNAs are increased in the DRG following CCI manipulation independent of injection treatment, suggesting that pathological conditions stimulate upregulation and availability of relevant receptors in critical anatomical regions required for the therapeutic actions of the DM/pDNA-IL-10 co-therapy. Taken together, the current report demonstrates that non-viral DM/pDNA-IL-10 gene therapy does not require endogenous IL-10 for enduring relief of peripheral neuropathic pain and does not require direct contact with the spinal cord dorsal horn for robust and enduring relief of neuropathic pain. Spinal non-viral DM/pDNA-IL-10 co-therapy may offer a framework for the development of non-viral gene therapeutic approaches for other diseases of the central nervous system.
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Affiliation(s)
- Arden G Vanderwall
- Department of Neurosciences, University of New Mexico School of Medicine, UNM Health Sciences Center, Albuquerque, NM 87131-0001, USA; Department of Anesthesiology & Critical Care Medicine, University of New Mexico School of Medicine, UNM Health Sciences Center, Albuquerque, NM 87131-0001, USA
| | - Shahani Noor
- Department of Neurosciences, University of New Mexico School of Medicine, UNM Health Sciences Center, Albuquerque, NM 87131-0001, USA
| | - Melody S Sun
- Department of Neurosciences, University of New Mexico School of Medicine, UNM Health Sciences Center, Albuquerque, NM 87131-0001, USA
| | - Jacob E Sanchez
- Department of Neurosciences, University of New Mexico School of Medicine, UNM Health Sciences Center, Albuquerque, NM 87131-0001, USA
| | - Xuexian O Yang
- Department of Molecular Genetics and Microbiology, University of New Mexico School of Medicine, UNM Health Sciences Center, Albuquerque, NM 87131-0001, USA
| | - Lauren L Jantzie
- Department of Neurosciences, University of New Mexico School of Medicine, UNM Health Sciences Center, Albuquerque, NM 87131-0001, USA; Department of Pediatrics, University of New Mexico School of Medicine, UNM Health Sciences Center, Albuquerque, NM 87131-0001, USA
| | - Nikolaos Mellios
- Department of Neurosciences, University of New Mexico School of Medicine, UNM Health Sciences Center, Albuquerque, NM 87131-0001, USA
| | - Erin D Milligan
- Department of Neurosciences, University of New Mexico School of Medicine, UNM Health Sciences Center, Albuquerque, NM 87131-0001, USA; Department of Anesthesiology & Critical Care Medicine, University of New Mexico School of Medicine, UNM Health Sciences Center, Albuquerque, NM 87131-0001, USA.
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28
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Abstract
Alzheimer's disease (AD) is the primary cause of age-related dementia. Effective strategies to prevent and treat AD remain elusive despite major efforts to understand its basic biology and clinical pathophysiology. Significant investments in therapeutic drug discovery programs over the past two decades have yielded some important insights but no blockbuster drugs to alter the course of disease. Because significant memory loss and cognitive decline are associated with neuron death and loss of gray matter, especially in the frontal cortex and hippocampus, some focus in drug development has shifted to early prevention of cellular pathology. Although clinical trial design is challenging, due in part to a lack of robust biomarkers with predictive value, some optimism has come from the identification and study of inherited forms of early-onset AD and genetic risk factors that provide insights about molecular pathophysiology and potential drug targets. In addition, better understanding of the Aβ amyloid pathway and the tau pathway-leading to amyloid plaques and neurofibrillary tangles, respectively, which are histopathological hallmarks of AD-continues to drive significant drug research and development programs. The main focus of this review is to summarize the most recent basic biology, biochemistry, and pharmacology that serve as a foundation for more than 50 active advanced-phase clinical trials for AD prevention and therapy.
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Affiliation(s)
- W Vallen Graham
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, NY 10065;
| | - Alessandra Bonito-Oliva
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, NY 10065;
| | - Thomas P Sakmar
- Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, NY 10065; .,Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, 141 57 Huddinge, Sweden
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29
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Choi MJ, Park JS, Park JE, Kim HS, Kim HS. Galangin Suppresses Pro-Inflammatory Gene Expression in Polyinosinic-Polycytidylic Acid-Stimulated Microglial Cells. Biomol Ther (Seoul) 2017; 25:641-647. [PMID: 29081092 PMCID: PMC5685434 DOI: 10.4062/biomolther.2017.173] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 09/15/2017] [Accepted: 09/19/2017] [Indexed: 11/17/2022] Open
Abstract
Galangin (3,5,7-trihydroxyflavone) is a polyphenolic compound abundant in honey and medicinal herbs, such as Alpinia officinarum. In this study, we investigated the anti-inflammatory effects of galangin under in vitro and in vivo neuroinflammatory conditions caused by polyinosinic-polycytidylic acid (poly(I:C)), a viral mimic dsRNA analog. Galangin suppressed the production of nitric oxide, reactive oxygen species, and pro-inflammatory cytokines in poly(I:C)-stimulated BV2 microglia. On the other hand, galangin enhanced anti-inflammatory interleukin (IL)-10 production. Galangin also suppressed the expression of pro-inflammatory markers in poly(I:C)-injected mouse brains. Further mechanistic studies showed that galangin inhibited poly(I:C)-induced nuclear factor (NF)-κB activity and phosphorylation of Akt without affecting MAP kinases. Interestingly, galangin increased the expression and transcriptional activity of peroxisome proliferator-activated receptor (PPAR)-γ, known to play an anti-inflammatory role. To investigate whether PPAR-γ is involved in the anti-inflammatory function of galangin, BV2 cells were pre-treated with PPAR-γ antagonist before treatment of galangin. We found that PPAR-γ antagonist significantly blocked galangin-mediated upregulation of IL-10 and attenuated the inhibition of tumor necrosis factor (TNF)-α and IL-6 in poly(I:C)-stimulated microglia. In conclusion, our data suggest that PI3K/Akt, NF-κB, and PPAR-γ play a pivotal role in mediating the anti-inflammatory effects of galangin in poly(I:C)-stimulated microglia.
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Affiliation(s)
- Min-Ji Choi
- Department of Molecular Medicine, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul 07985, Republic of Korea
| | - Jin-Sun Park
- Department of Molecular Medicine, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul 07985, Republic of Korea
| | - Jung-Eun Park
- Department of Molecular Medicine, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul 07985, Republic of Korea
| | - Han Su Kim
- Department of Otorhinolaryngology, School of Medicine, Ewha Womans University, Seoul 07985, Republic of Korea
| | - Hee-Sun Kim
- Department of Molecular Medicine, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul 07985, Republic of Korea
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30
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Abstract
Microglia are brain-resident myeloid cells that mediate key functions to support the CNS. Microglia express a wide range of receptors that act as molecular sensors, which recognize exogenous or endogenous CNS insults and initiate an immune response. In addition to their classical immune cell function, microglia act as guardians of the brain by promoting phagocytic clearance and providing trophic support to ensure tissue repair and maintain cerebral homeostasis. Conditions associated with loss of homeostasis or tissue changes induce several dynamic microglial processes, including changes of cellular morphology, surface phenotype, secretory mediators, and proliferative responses (referred to as an "activated state"). Activated microglia represent a common pathological feature of several neurodegenerative diseases, including Alzheimer's disease (AD). Cumulative evidence suggests that microglial inflammatory activity in AD is increased while microglial-mediated clearance mechanisms are compromised. Microglia are perpetually engaged in a mutual interaction with the surrounding environment in CNS; thus, diverse microglial reactions at different disease stages may open new avenues for therapeutic intervention and modification of inflammatory activities. In this Review, the role of microglia in the pathogenesis of AD and the modulation of microglia activity as a therapeutic modality will be discussed.
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Affiliation(s)
- Heela Sarlus
- Department of Neurodegenerative Diseases and Gerontopsychiatry, University of Bonn, Bonn, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Bonn, Germany
| | - Michael T Heneka
- Department of Neurodegenerative Diseases and Gerontopsychiatry, University of Bonn, Bonn, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Bonn, Germany.,Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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31
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Jung JS, Choi MJ, Lee YY, Moon BI, Park JS, Kim HS. Suppression of Lipopolysaccharide-Induced Neuroinflammation by Morin via MAPK, PI3K/Akt, and PKA/HO-1 Signaling Pathway Modulation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:373-382. [PMID: 28032996 DOI: 10.1021/acs.jafc.6b05147] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Morin is a flavonoid isolated from certain fruits and Chinese herbs and is known to possess various medicinal properties. In this study, we investigated the anti-inflammatory effects of morin on lipopolysaccharide (LPS)-induced microglial activation, both in vitro and in vivo. We found that morin inhibited inducible nitric oxide synthase (iNOS) and pro-inflammatory cytokines in LPS-stimulated BV2 microglial cells. Furthermore, morin suppressed the microglial activation and cytokine expression in the brains of LPS-stimulated mice. Subsequent mechanistic studies revealed that morin inhibited the action of LPS-activated mitogen-activated protein kinases (MAPKs), protein kinase B (Akt) phosphorylation, nuclear factor-κB (NF-κB), and activating protein-1 (AP-1). Further, the phosphorylation and DNA binding activity of cAMP responsive element binding protein (CREB) was enhanced by morin. Moreover, morin suppressed the LPS-induced expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, while it increased heme oxygenase-1 (HO-1) expression and nuclear factor erythroid 2-related factor 2 (Nrf2) activation. Therefore, our data suggest that morin exerts anti-inflammatory effects in LPS-stimulated microglia by downregulating MAPK and phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways while upregulating protein kinase A (PKA)/CREB and Nrf2/HO-1 signaling pathways.
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Affiliation(s)
- Ji-Sun Jung
- Division of Functional Food Research, Korea Food Research Institute , Gyeonggi-do 463-746, Republic of Korea
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32
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Analysis of gene expression in the nervous system identifies key genes and novel candidates for health and disease. Neurogenetics 2017; 18:81-95. [PMID: 28190221 PMCID: PMC5359387 DOI: 10.1007/s10048-017-0509-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 01/20/2017] [Indexed: 01/09/2023]
Abstract
The incidence of neurodegenerative diseases in the developed world has risen over the last century, concomitant with an increase in average human lifespan. A major challenge is therefore to identify genes that control neuronal health and viability with a view to enhancing neuronal health during ageing and reducing the burden of neurodegeneration. Analysis of gene expression data has recently been used to infer gene functions for a range of tissues from co-expression networks. We have now applied this approach to transcriptomic datasets from the mammalian nervous system available in the public domain. We have defined the genes critical for influencing neuronal health and disease in different neurological cell types and brain regions. The functional contribution of genes in each co-expression cluster was validated using human disease and knockout mouse phenotypes, pathways and gene ontology term annotation. Additionally a number of poorly annotated genes were implicated by this approach in nervous system function. Exploiting gene expression data available in the public domain allowed us to validate key nervous system genes and, importantly, to identify additional genes with minimal functional annotation but with the same expression pattern. These genes are thus novel candidates for a role in neurological health and disease and could now be further investigated to confirm their function and regulation during ageing and neurodegeneration.
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33
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Soluble phospho-tau from Alzheimer's disease hippocampus drives microglial degeneration. Acta Neuropathol 2016; 132:897-916. [PMID: 27743026 PMCID: PMC5106501 DOI: 10.1007/s00401-016-1630-5] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 10/05/2016] [Accepted: 10/05/2016] [Indexed: 01/22/2023]
Abstract
The role of microglial cells in the development and progression of Alzheimer's disease (AD) has not been elucidated. Here, we demonstrated the existence of a weak microglial response in human AD hippocampus which is in contrast to the massive microglial activation observed in APP-based models. Most importantly, microglial cells displayed a prominent degenerative profile (dentate gyrus > CA3 > CA1 > parahippocampal gyrus), including fragmented and dystrophic processes with spheroids, a reduced numerical density, and a significant decrease in the area of surveillance ("microglial domain"). Consequently, there was a substantial decline in the area covered by microglia which may compromise immune protection and, therefore, neuronal survival. In vitro experiments demonstrated that soluble fractions (extracellular/cytosolic) from AD hippocampi were toxic for microglial cells. This toxicity was abolished by AT8 and/or AT100 immunodepletion, validating that soluble phospho-tau was the toxic agent. These results were reproduced using soluble fractions from phospho-tau-positive Thy-tau22 hippocampi. Cultured microglial cells were not viable following phagocytosis of SH-SY5Y cells expressing soluble intracellular phospho-tau. Because the phagocytic capacity of microglial cells is highly induced by apoptotic signals in the affected neurons, we postulate that accumulation of intraneuronal soluble phospho-tau might trigger microglial degeneration in the AD hippocampus. This microglial vulnerability in AD pathology provides new insights into the immunological mechanisms underlying the disease progression and highlights the need to improve or develop new animal models, as the current models do not mimic the microglial pathology observed in the hippocampus of AD patients.
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