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Chen HJC, Spiers JG, Lerskiatiphanich T, Parker SE, Lavidis NA, Fung JN, Woodruff TM, Lee JD. Complement C5a Receptor Signaling Alters Stress Responsiveness and Modulates Microglia Following Chronic Stress Exposure. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2024; 4:100306. [PMID: 38628385 PMCID: PMC11019103 DOI: 10.1016/j.bpsgos.2024.100306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 02/26/2024] [Accepted: 02/28/2024] [Indexed: 04/19/2024] Open
Abstract
Background Accumulating evidence underscores the pivotal role of heightened inflammation in the pathophysiology of stress-related diseases, but the underlying mechanisms remain elusive. The complement system, a key effector of the innate immune system, produces the C5-cleaved activation product C5a upon activation, initiating inflammatory responses through the canonical C5a receptor 1 (C5aR1). While C5aR1 is expressed in stress-responsive brain regions, its role in stress responsiveness remains unknown. Methods To investigate C5a-C5aR1 signaling in stress responses, mice underwent acute and chronic stress paradigms. Circulating C5a levels and messenger RNA expression of C5aR1 in the hippocampus and adrenal gland were measured. C5aR1-deficient mice were used to elucidate the effects of disrupted C5a-C5aR1 signaling across behavioral, hormonal, metabolic, and inflammation parameters. Results Chronic restraint stress elevated circulating C5a levels while reducing C5aR1 messenger RNA expression in the hippocampus and adrenal gland. Notably, the absence of C5aR1 signaling enhanced adrenal sensitivity to adrenocorticotropic hormone, concurrently reducing pituitary adrenocorticotropic hormone production and enhancing the response to acute stress. C5aR1-deficient mice exhibited attenuated reductions in locomotor activity and body weight under chronic stress. Additionally, these mice displayed increased glucocorticoid receptor sensitivity and disrupted glucose and insulin homeostasis. Chronic stress induced an increase in C5aR1-expressing microglia in the hippocampus, a response mitigated in C5aR1-deficient mice. Conclusions C5a-C5aR1 signaling emerges as a key metabolic regulator during stress, suggesting that complement activation and dysfunctional C5aR1 signaling may contribute to neuroinflammatory phenotypes in stress-related disorders. The results advocate for further exploration of complement C5aR1 as a potential therapeutic target for stress-related conditions.
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Affiliation(s)
- Hsiao-Jou Cortina Chen
- School of Biomedical Sciences, the University of Queensland, St. Lucia, Brisbane, Queensland, Australia
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Jereme G. Spiers
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
- Clear Vision Research, Eccles Institute of Neuroscience, John Curtin School of Medical Research, College of Health and Medicine, the Australian National University, Acton, Australian Capital Territory, Australia
- School of Medicine and Psychology, College of Health and Medicine, the Australian National University, Australian Capital Territory, Australia
| | - Titaya Lerskiatiphanich
- School of Biomedical Sciences, the University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Sandra E. Parker
- School of Biomedical Sciences, the University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Nickolas A. Lavidis
- School of Biomedical Sciences, the University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Jenny N. Fung
- School of Biomedical Sciences, the University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Trent M. Woodruff
- School of Biomedical Sciences, the University of Queensland, St. Lucia, Brisbane, Queensland, Australia
- Queensland Brain Institute, the University of Queensland, St Lucia, Brisbane, Queensland, Australia
| | - John D. Lee
- School of Biomedical Sciences, the University of Queensland, St. Lucia, Brisbane, Queensland, Australia
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Gomez‐Arboledas A, Fonseca MI, Kramar E, Chu S, Schartz ND, Selvan P, Wood MA, Tenner AJ. C5aR1 signaling promotes region- and age-dependent synaptic pruning in models of Alzheimer's disease. Alzheimers Dement 2024; 20:2173-2190. [PMID: 38278523 PMCID: PMC10984438 DOI: 10.1002/alz.13682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 01/28/2024]
Abstract
INTRODUCTION Synaptic loss is a hallmark of Alzheimer's disease (AD) that correlates with cognitive decline in AD patients. Complement-mediated synaptic pruning has been associated with this excessive loss of synapses in AD. Here, we investigated the effect of C5aR1 inhibition on microglial and astroglial synaptic pruning in two mouse models of AD. METHODS A combination of super-resolution and confocal and tridimensional image reconstruction was used to assess the effect of genetic ablation or pharmacological inhibition of C5aR1 on the Arctic48 and Tg2576 models of AD. RESULTS Genetic ablation or pharmacological inhibition of C5aR1 partially rescues excessive pre-synaptic pruning and synaptic loss in an age and region-dependent fashion in two mouse models of AD, which correlates with improved long-term potentiation (LTP). DISCUSSION Reduction of excessive synaptic pruning is an additional beneficial outcome of the suppression of C5a-C5aR1 signaling, further supporting its potential as an effective targeted therapy to treat AD. HIGHLIGHTS C5aR1 ablation restores long-term potentiation in the Arctic model of AD. C5aR1 ablation rescues region specific excessive pre-synaptic loss. C5aR1 antagonist, PMX205, rescues VGlut1 loss in the Tg2576 model of AD. C1q tagging is not sufficient to induce VGlut1 microglial ingestion. Astrocytes contribute to excessive pre-synaptic loss at late stages of the disease.
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Affiliation(s)
- Angela Gomez‐Arboledas
- Department of Molecular Biology and BiochemistryUniversity of CaliforniaIrvineCaliforniaUSA
| | - Maria I. Fonseca
- Department of Molecular Biology and BiochemistryUniversity of CaliforniaIrvineCaliforniaUSA
| | - Enikö Kramar
- Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
| | - Shu‐Hui Chu
- Department of Molecular Biology and BiochemistryUniversity of CaliforniaIrvineCaliforniaUSA
| | - Nicole D. Schartz
- Department of Molecular Biology and BiochemistryUniversity of CaliforniaIrvineCaliforniaUSA
| | - Purnika Selvan
- Department of Molecular Biology and BiochemistryUniversity of CaliforniaIrvineCaliforniaUSA
| | - Marcelo A. Wood
- Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
| | - Andrea J. Tenner
- Department of Molecular Biology and BiochemistryUniversity of CaliforniaIrvineCaliforniaUSA
- Department of Neurobiology and BehaviorUniversity of CaliforniaIrvineCaliforniaUSA
- Department of Pathology and Laboratory MedicineUniversity of CaliforniaSchool of MedicineIrvineCaliforniaUSA
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3
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Gomez-Arboledas A, Fonseca MI, Kramar E, Chu SH, Schartz N, Selvan P, Wood MA, Tenner AJ. C5aR1 signaling promotes region and age dependent synaptic pruning in models of Alzheimer's Disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.29.560234. [PMID: 37873302 PMCID: PMC10592845 DOI: 10.1101/2023.09.29.560234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
INTRODUCTION Synaptic loss is a hallmark of Alzheimer's disease (AD) that correlates with cognitive decline in AD patients. Complement-mediated synaptic pruning has been associated with this excessive loss of synapses in AD. Here, we investigated the effect of C5aR1 inhibition on microglial and astroglial synaptic pruning in two mouse models of AD. METHODS A combination of super-resolution and confocal and tridimensional image reconstruction was used to assess the effect of genetic ablation or pharmacological inhibition of C5aR1 on the Arctic48 and Tg2576 models of AD. RESULTS Genetic ablation or pharmacological inhibition of C5aR1 rescues the excessive pre-synaptic pruning and synaptic loss in an age and region dependent fashion in two mouse models of AD, which correlates with improved long-term potentiation (LTP). DISCUSSION Reduction of excessive synaptic pruning is an additional beneficial outcome of the suppression of C5a-C5aR1 signaling, further supporting its potential as an effective targeted therapy to treat AD.
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Affiliation(s)
- Angela Gomez-Arboledas
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Maria I. Fonseca
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Enikö Kramar
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA
| | - Shu-Hui Chu
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Nicole Schartz
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Purnika Selvan
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Marcelo A. Wood
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA
| | - Andrea J. Tenner
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697, USA
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA
- Department of Pathology and Laboratory Medicine, University of California, Irvine, School of Medicine, Irvine, CA 92697, USA
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4
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Parker SE, Bellingham MC, Woodruff TM. Complement drives circuit modulation in the adult brain. Prog Neurobiol 2022; 214:102282. [DOI: 10.1016/j.pneurobio.2022.102282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/24/2022] [Accepted: 05/02/2022] [Indexed: 11/16/2022]
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Berkowitz S, Chapman J, Dori A, Gofrit SG, Maggio N, Shavit-Stein E. Complement and Coagulation System Crosstalk in Synaptic and Neural Conduction in the Central and Peripheral Nervous Systems. Biomedicines 2021; 9:biomedicines9121950. [PMID: 34944766 PMCID: PMC8698364 DOI: 10.3390/biomedicines9121950] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 12/12/2022] Open
Abstract
Complement and coagulation are both key systems that defend the body from harm. They share multiple features and are similarly activated. They each play individual roles in the systemic circulation in physiology and pathophysiology, with significant crosstalk between them. Components from both systems are mapped to important structures in the central nervous system (CNS) and peripheral nervous system (PNS). Complement and coagulation participate in critical functions in neuronal development and synaptic plasticity. During pathophysiological states, complement and coagulation factors are upregulated and can modulate synaptic transmission and neuronal conduction. This review summarizes the current evidence regarding the roles of the complement system and the coagulation cascade in the CNS and PNS. Possible crosstalk between the two systems regarding neuroinflammatory-related effects on synaptic transmission and neuronal conduction is explored. Novel treatment based on the modulation of crosstalk between complement and coagulation may perhaps help to alleviate neuroinflammatory effects in diseased states of the CNS and PNS.
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Affiliation(s)
- Shani Berkowitz
- Department of Neurology, The Chaim Sheba Medical Center, Ramat Gan 5266202, Israel; (S.B.); (J.C.); (A.D.); (S.G.G.); (N.M.)
- Department of Neurology and Neurosurgery, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Joab Chapman
- Department of Neurology, The Chaim Sheba Medical Center, Ramat Gan 5266202, Israel; (S.B.); (J.C.); (A.D.); (S.G.G.); (N.M.)
- Department of Neurology and Neurosurgery, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
- Robert and Martha Harden Chair in Mental and Neurological Diseases, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Amir Dori
- Department of Neurology, The Chaim Sheba Medical Center, Ramat Gan 5266202, Israel; (S.B.); (J.C.); (A.D.); (S.G.G.); (N.M.)
- Department of Neurology and Neurosurgery, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
- Talpiot Medical Leadership Program, The Chaim Sheba Medical Center, Ramat Gan 6997801, Israel
| | - Shany Guly Gofrit
- Department of Neurology, The Chaim Sheba Medical Center, Ramat Gan 5266202, Israel; (S.B.); (J.C.); (A.D.); (S.G.G.); (N.M.)
| | - Nicola Maggio
- Department of Neurology, The Chaim Sheba Medical Center, Ramat Gan 5266202, Israel; (S.B.); (J.C.); (A.D.); (S.G.G.); (N.M.)
- Department of Neurology and Neurosurgery, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
- Talpiot Medical Leadership Program, The Chaim Sheba Medical Center, Ramat Gan 6997801, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Efrat Shavit-Stein
- Department of Neurology, The Chaim Sheba Medical Center, Ramat Gan 5266202, Israel; (S.B.); (J.C.); (A.D.); (S.G.G.); (N.M.)
- Department of Neurology and Neurosurgery, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
- Correspondence: ; Tel.: +972-50-921-0400
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Manabe T, Rácz I, Schwartz S, Oberle L, Santarelli F, Emmrich JV, Neher JJ, Heneka MT. Systemic inflammation induced the delayed reduction of excitatory synapses in the CA3 during ageing. J Neurochem 2021; 159:525-542. [PMID: 34379806 DOI: 10.1111/jnc.15491] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 07/27/2021] [Accepted: 08/09/2021] [Indexed: 11/29/2022]
Abstract
Sepsis-associated encephalopathy (SAE) represents diverse cerebral dysfunctions in response to pathogen-induced systemic inflammation. Peripheral exposure to lipopolysaccharide (LPS), a component of the gram-negative bacterial cell wall, has been extensively used to model systemic inflammation. Our previous studies suggested that LPS led to hippocampal neuron death and synaptic destruction in vivo. However, the underlying roles of activated microglia in these neuronal changes remained unclear. Here, LPS from two different bacterial strains (Salmonella enterica or E. coli) were compared and injected in 14- to 16-month-old mice and evaluated for neuroinflammation and neuronal integrity in the hippocampus at 7 or 63 days post-injection (dpi). LPS injection resulted in persistent neuroinflammation lasting for seven days and a subsequent normalisation by 63 dpi. Of note, increases in proinflammatory cytokines, microglial morphology and microglial mean lysosome volume were more pronounced after E. coli LPS injection than Salmonella LPS at 7 dpi. While inhibitory synaptic puncta density remained normal, excitatory synaptic puncta were locally reduced in the CA3 region of the hippocampus at 63 dpi. Finally, we provide evidence that excitatory synapses coated with complement factor 3 (C3) decreased between 7 dpi and 63 dpi. Although we did not find an increase of synaptic pruning by microglia, it is plausible that microglia recognised and eliminated these C3-tagged synapses between the two time-points of investigation. Since a region-specific decline of CA3 synapses has previously been reported during normal ageing, we postulate that systemic inflammation may have accelerated or worsened the CA3 synaptic changes in the ageing brain.
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Affiliation(s)
- Tatsuya Manabe
- Department of Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn Medical Center, Venusberg-Campus 1, 53127, Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany
| | - Ildikó Rácz
- Department of Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn Medical Center, Venusberg-Campus 1, 53127, Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany
| | - Stephanie Schwartz
- Department of Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn Medical Center, Venusberg-Campus 1, 53127, Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany
| | - Linda Oberle
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076, Tübingen, Germany
| | | | - Julius V Emmrich
- Department of Neurology and Department of Experimental Neurology, Freie Universität Berlin, Humboldt Universität zu Berlin, Berlin Institute of Health, Berlin, 10117, Germany
| | - Jonas J Neher
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), 72076, Tübingen, Germany
| | - Michael T Heneka
- Department of Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn Medical Center, Venusberg-Campus 1, 53127, Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany.,Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655, USA
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Ma Y, Liu Y, Zhang Z, Yang GY. Significance of Complement System in Ischemic Stroke: A Comprehensive Review. Aging Dis 2019; 10:429-462. [PMID: 31011487 PMCID: PMC6457046 DOI: 10.14336/ad.2019.0119] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/19/2019] [Indexed: 12/14/2022] Open
Abstract
The complement system is an essential part of innate immunity, typically conferring protection via eliminating pathogens and accumulating debris. However, the defensive function of the complement system can exacerbate immune, inflammatory, and degenerative responses in various pathological conditions. Cumulative evidence indicates that the complement system plays a critical role in the pathogenesis of ischemic brain injury, as the depletion of certain complement components or the inhibition of complement activation could reduce ischemic brain injury. Although multiple candidates modulating or inhibiting complement activation show massive potential for the treatment of ischemic stroke, the clinical availability of complement inhibitors remains limited. The complement system is also involved in neural plasticity and neurogenesis during cerebral ischemia. Thus, unexpected side effects could be induced if the systemic complement system is inhibited. In this review, we highlighted the recent concepts and discoveries of the roles of different kinds of complement components, such as C3a, C5a, and their receptors, in both normal brain physiology and the pathophysiology of brain ischemia. In addition, we comprehensively reviewed the current development of complement-targeted therapy for ischemic stroke and discussed the challenges of bringing these therapies into the clinic. The design of future experiments was also discussed to better characterize the role of complement in both tissue injury and recovery after cerebral ischemia. More studies are needed to elucidate the molecular and cellular mechanisms of how complement components exert their functions in different stages of ischemic stroke to optimize the intervention of targeting the complement system.
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Affiliation(s)
- Yuanyuan Ma
- 1Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,2Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yanqun Liu
- 3Department of Neurology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Zhijun Zhang
- 2Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Guo-Yuan Yang
- 1Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,2Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
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8
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Roselli F, Karasu E, Volpe C, Huber-Lang M. Medusa's Head: The Complement System in Traumatic Brain and Spinal Cord Injury. J Neurotrauma 2017; 35:226-240. [PMID: 28816089 DOI: 10.1089/neu.2017.5168] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Traumatic brain injury (TBI) and spinal cord injury (SCI) are critical medical conditions and a public health problem for which limited therapeutic options are available. The complement cascade is activated after TBI and SCI, and the resulting effects have been investigated in gene-knockout and pharmacological models. Multiple experimental studies support a net detrimental role of C3 and C5 activation in the early stages of TBI and SCI. Less firm experimental evidence suggests that, downstream of C3/C5, effector mechanisms, including the generation of membrane-activated complex and direct damage to membranes and neutrophils infiltration, may bring about the direct damage of central nervous system tissue and enhancement of neuroinflammation. The role of upstream classical, alternative, or extrinsic complement activation cascades remains unclear. Although several issues remain to be investigated, current evidence supports the investigation of a number of complement-targeting agents targeting C3 or C5, such as eculizumab, for repurposing in TBI and SCI treatment.
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Affiliation(s)
- Francesco Roselli
- 1 Department of Neurology, Medical School, University of Ulm , Ulm, Germany
- 2 Department of Anatomy and Cell Biology, Medical School, University of Ulm , Ulm, Germany
| | - Ebru Karasu
- 3 Institute of Clinical and Experimental Trauma-Immunology, Medical School, University of Ulm , Ulm, Germany
| | - Clara Volpe
- 1 Department of Neurology, Medical School, University of Ulm , Ulm, Germany
| | - Markus Huber-Lang
- 3 Institute of Clinical and Experimental Trauma-Immunology, Medical School, University of Ulm , Ulm, Germany
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Shah TA, Nejad JE, Pallera HK, Lattanzio FA, Farhat R, Kumar PS, Hair PS, Bass WT, Krishna NK. Therapeutic hypothermia modulates complement factor C3a and C5a levels in a rat model of hypoxic ischemic encephalopathy. Pediatr Res 2017; 81:654-662. [PMID: 28002390 DOI: 10.1038/pr.2016.271] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/08/2016] [Indexed: 12/17/2022]
Abstract
BACKGROUND Therapeutic hypothermia (HT) is the only intervention that improves outcomes in neonatal hypoxic-ischemic encephalopathy (HIE). However, the multifactorial mechanisms by which HT impacts HIE are incompletely understood. The complement system plays a major role in the pathogenesis of ischemia-reperfusion injuries such as HIE. We have previously demonstrated that HT modulates complement activity in vitro. METHODS Term equivalent rat pups were subjected to unilateral carotid ligation followed by hypoxia (8% O2) for 45 min to simulate HIE. A subset of animals was subjected to HT (31-32°C for 6 h). Plasma and brain levels of C3a and C5a were measured. Receptors for C3a (C3aR) and C5a (C5aR) along with C1q, C3, and C9 were characterized in neurons, astrocytes, and microglia. RESULTS We found that HT increased systemic expression of C3a and decreased expression of C5a after HIE. In the brain, C3aR and C5aR are predominantly expressed on microglia after HIE. HT increased local expression of C3aR and decreased expression on C5aR after HIE. Furthermore, HT decreased local expression of C1q, C3-products, and C9 in the brain. CONCLUSION HT is associated with significant alteration of complement effectors and their cognate receptors. Complement modulation may improve outcomes in neonatal HIE.
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Affiliation(s)
- Tushar A Shah
- Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia.,Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia.,Children's Specialty Group, Norfolk, Virginia.,Division of Neonatology, Children's Hospital of The King's Daughters, Norfolk, Virginia
| | - Jasmine E Nejad
- Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia
| | - Haree K Pallera
- Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia
| | - Frank A Lattanzio
- Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia
| | - Rawad Farhat
- Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia
| | - Parvathi S Kumar
- Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia
| | - Pamela S Hair
- Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia
| | - W Thomas Bass
- Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia.,Children's Specialty Group, Norfolk, Virginia.,Division of Neonatology, Children's Hospital of The King's Daughters, Norfolk, Virginia
| | - Neel K Krishna
- Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia.,Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia
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Peña-Ortega F. Pharmacological Tools to Activate Microglia and their Possible use to Study Neural Network Patho-physiology. Curr Neuropharmacol 2017; 15:595-619. [PMID: 27697040 PMCID: PMC5543677 DOI: 10.2174/1570159x14666160928151546] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/05/2016] [Accepted: 09/26/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Microglia are the resident immunocompetent cells of the CNS and also constitute a unique cell type that contributes to neural network homeostasis and function. Understanding microglia cell-signaling not only will reveal their diverse functions but also will help to identify pharmacological and non-pharmacological tools to modulate the activity of these cells. METHODS We undertook a search of bibliographic databases for peer-reviewed research literature to identify microglial activators and their cell-specificity. We also looked for their effects on neural network function and dysfunction. RESULTS We identified several pharmacological targets to modulate microglial function, which are more or less specific (with the proper control experiments). We also identified pharmacological targets that would require the development of new potent and specific modulators. We identified a wealth of evidence about the participation of microglia in neural network function and their alterations in pathological conditions. CONCLUSION The identification of specific microglia-activating signals provides experimental tools to modulate the activity of this heterogeneous cell type in order to evaluate its impact on other components of the nervous system, and it also helps to identify therapeutic approaches to ease some pathological conditions related to microglial dysfunction.
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Affiliation(s)
- Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
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11
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Alawieh A, Elvington A, Tomlinson S. Complement in the Homeostatic and Ischemic Brain. Front Immunol 2015; 6:417. [PMID: 26322048 PMCID: PMC4533015 DOI: 10.3389/fimmu.2015.00417] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/30/2015] [Indexed: 11/29/2022] Open
Abstract
The complement system is a component of the immune system involved in both recognition and response to pathogens, and it is implicated in an increasing number of homeostatic and disease processes. It is well documented that reperfusion of ischemic tissue results in complement activation and an inflammatory response that causes post-reperfusion injury. This occurs following cerebral ischemia and reperfusion and triggers secondary damage that extends beyond the initial infarcted area, an outcome that has rationalized the use of complement inhibitors as candidate therapeutics after stroke. In the central nervous system, however, recent studies have revealed that complement also has essential roles in synaptic pruning, neurogenesis, and neuronal migration. In the context of recovery after stroke, these apparent divergent functions of complement may account for findings that the protective effect of complement inhibition in the acute phase after stroke is not always maintained in the subacute and chronic phases. The development of effective stroke therapies based on modulation of the complement system will require a detailed understanding of complement-dependent processes in both early neurodegenerative events and delayed neuro-reparatory processes. Here, we review the role of complement in normal brain physiology, the events initiating complement activation after cerebral ischemia-reperfusion injury, and the contribution of complement to both injury and recovery. We also discuss how the design of future experiments may better characterize the dual role of complement in recovery after ischemic stroke.
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Affiliation(s)
- Ali Alawieh
- Neuroscience Institute, Department of Neurosciences, Medical University of South Carolina , Charleston, SC , USA
| | - Andrew Elvington
- Department of Pathology and Immunology, Washington University School of Medicine , St. Louis, MO , USA
| | - Stephen Tomlinson
- Department of Microbiology and Immunology, Ralph H. Johnson Veteran Affairs Medical Center, Medical University of South Carolina , Charleston, SC , USA
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12
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Lee JD, Kamaruzaman NA, Fung JNT, Taylor SM, Turner BJ, Atkin JD, Woodruff TM, Noakes PG. Dysregulation of the complement cascade in the hSOD1G93A transgenic mouse model of amyotrophic lateral sclerosis. J Neuroinflammation 2013; 10:119. [PMID: 24067070 PMCID: PMC3850877 DOI: 10.1186/1742-2094-10-119] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 09/06/2013] [Indexed: 12/13/2022] Open
Abstract
Background Components of the innate immune complement system have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS); however, a comprehensive examination of complement expression in this disease has not been performed. This study therefore aimed to determine the expression of complement components (C1qB, C4, factor B, C3/C3b, C5 and CD88) and regulators (CD55 and CD59a) in the lumbar spinal cord of hSOD1G93A mice during defined disease stages. Methods hSOD1G93A and wild-type mice were examined at four different ages of disease progression. mRNA and protein expression of complement components and regulators were examined using quantitative PCR, western blotting and ELISA. Localisation of complement components within lumbar spinal cord was investigated using immunohistochemistry. Statistical differences between hSOD1G93A and wild-type mice were analysed using a two-tailed t-test at each stage of disease progression. Results We found several early complement factors increased as disease progressed, whilst complement regulators decreased; suggesting overall increased complement activation through the classical or alternative pathways in hSOD1G93A mice. CD88 was also increased during disease progression, with immunolocalisation demonstrating expression on motor neurons and increasing expression on microglia surrounding the regions of motor neuron death. Conclusions These results indicate that local complement activation and increased expression of CD88 may contribute to motor neuron death and ALS pathology in the hSOD1G93A mouse. Hence, reducing complement-induced inflammation could be an important therapeutic strategy to treat ALS.
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Affiliation(s)
- John D Lee
- School of Biomedical Sciences, University of Queensland, Brisbane, St Lucia QLD 4072, Australia.
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Chmilewsky F, Jeanneau C, Laurent P, Kirschfink M, About I. Pulp progenitor cell recruitment is selectively guided by a C5a gradient. J Dent Res 2013; 92:532-9. [PMID: 23603337 DOI: 10.1177/0022034513487377] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
It recently became evident that activation of the complement system also contributes to tissue regeneration after infection/injury. The complement-derived fragment C5a induces vascular modifications and attracts cells expressing its receptor (C5aR/CD88) to the site of infection and tissue injury. Besides inflammatory cells, various tissue cells express this receptor. We hypothesized that pulp progenitor cells, being exposed to local complement activation in caries lesions, may respond to C5a via the C5aR. Our work aimed at evaluating the ability of C5a to induce pulp progenitor cell migration that may link complement activation to dentin regeneration. Immunofluorescence analysis of third molar pulp sections showed perivascular localization of the mesenchymal stem cell markers STRO-1 and C5aR. RT-PCR on STRO-1-sorted pulp progenitor cells, co-expressing both STRO-1 and C5aR, revealed high C5aR mRNA levels. Experiments with the C5aR antagonist W54011 revealed that C5a specifically bound to progenitor cells via C5aR, inducing their selective migration toward the C5a gradient. Since we could also demonstrate C5b-9 formation by immunohistochemistry in carious teeth, our findings suggest that, upon local complement activation, C5a induces pulp progenitor cell migration, which may be critical in initiating the regenerative process after dentin/pulp injury.
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Affiliation(s)
- F Chmilewsky
- Aix-Marseille Université, CNRS, ISM UMR 7287, 13288, Marseille cedex 09, France
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Fonseca MI, McGuire SO, Counts SE, Tenner AJ. Complement activation fragment C5a receptors, CD88 and C5L2, are associated with neurofibrillary pathology. J Neuroinflammation 2013; 10:25. [PMID: 23394121 PMCID: PMC3605123 DOI: 10.1186/1742-2094-10-25] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 01/28/2013] [Indexed: 12/30/2022] Open
Abstract
Background Alzheimer’s disease (AD) is a neurodegenerative dementia characterized by the decline of cognition and the presence of neuropathological changes including neuronal loss, neurofibrillary pathology and extracellular senile plaques. A neuroinflammatory process is also triggered and complement activation has been hypothesized to have a relevant role in this local inflammatory response. C5a, a proinflammatory anaphylatoxin generated after complement activation, exerts its chemotactic and inflammatory functions through the CD88 receptor while the more recently discovered C5L2 receptor has been postulated to have an anti-inflammatory role. Previously, we reported that a CD88 specific antagonist (PMX205) decreased the pathology and improved cognition in transgenic models of AD suggesting that C5a/C5aR interaction has an important role in the progression of the disease. Methods The present study characterizes the expression of the two receptors for C5a in human brain with confirmed post mortem diagnosis of vascular dementia (VD) or AD as well as age matched controls by immunohistochemistry and Western blot analysis using several antibodies against different epitopes of the human receptors. Results The CD88 and C5L2 antibodies revealed increased expression of both receptors in AD samples as compared to age-matched controls or VD brain tissue by Western blot and immunohistochemistry, using multiple antibodies and distinct cohorts of brain tissue. Immunostaining showed that both the C5L2 and CD88 antibodies similarly labeled abundant neurofibrillary tangles, neuropil threads and dystrophic neurites associated with plaques in the hippocampus and frontal cortex of AD cases. In contrast, little or no neuronal staining, tangles or dystrophic neurites associated with plaques were observed in control or VD brains. CD88 and C5L2 receptors are associated with both early (AT8) and mature (PHF1) neurofibrillary tangles and can be found either independently or colocalized with each other. Conclusions The observed association of CD88 and C5L2 with neurofibrillary pathology suggests a common altered pathway of degradation.
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Affiliation(s)
- Maria I Fonseca
- Dept of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA
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Brennan FH, Anderson AJ, Taylor SM, Woodruff TM, Ruitenberg MJ. Complement activation in the injured central nervous system: another dual-edged sword? J Neuroinflammation 2012; 9:137. [PMID: 22721265 PMCID: PMC3464784 DOI: 10.1186/1742-2094-9-137] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 06/21/2012] [Indexed: 11/28/2022] Open
Abstract
The complement system, a major component of the innate immune system, is becoming increasingly recognised as a key participant in physiology and disease. The awareness that immunological mediators support various aspects of both normal central nervous system (CNS) function and pathology has led to a renaissance of complement research in neuroscience. Various studies have revealed particularly novel findings on the wide-ranging involvement of complement in neural development, synapse elimination and maturation of neural networks, as well as the progression of pathology in a range of chronic neurodegenerative disorders, and more recently, neurotraumatic events, where rapid disruption of neuronal homeostasis potently triggers complement activation. The purpose of this review is to summarise recent findings on complement activation and acquired brain or spinal cord injury, i.e. ischaemic-reperfusion injury or stroke, traumatic brain injury (TBI) and spinal cord injury (SCI), highlighting the potential for complement-targeted therapeutics to alleviate the devastating consequences of these neurological conditions.
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Affiliation(s)
- Faith H Brennan
- The University of Queensland, School of Biomedical Sciences, St Lucia, Brisbane, QLD 4072, Australia
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Pavlovski D, Thundyil J, Monk PN, Wetsel RA, Taylor SM, Woodruff TM. Generation of complement component C5a by ischemic neurons promotes neuronal apoptosis. FASEB J 2012; 26:3680-90. [PMID: 22651932 DOI: 10.1096/fj.11-202382] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
C5a receptors are found in the central nervous system (CNS), on both neurons and glia. However, the origin of the C5a, which activates these receptors, is unclear. In the present study, we show that primary cultured mouse cortical neurons constitutively express C5, the precursor of C5a, and express the classical receptor for C5a, CD88. With cell ischemia caused by 12 h glucose deprivation, or oxygen-glucose deprivation (OGD), neurons demonstrated increased apoptosis, up-regulation of CD88, and increased levels of C5a in the media. Exogenous murine C5a (100 nM) added to the neuronal cultures resulted in apoptosis, without affecting cell necrosis. Pretreatment of the cells with the specific CD88 receptor antagonist PMX53 (100 nM) significantly blocked ischemia-induced apoptosis (∼50%), and neurons from CD88(-/-) mice were similarly protected. In a murine model of stroke, using middle cerebral artery occlusion (MCAO), we found that C5a levels in the brain increased; this also occurred in cerebral slice cultures exposed to OGD. CD88(-/-) mice subjected to MCAO had significantly reduced infarct volumes and improved neurological scores. Taken together, our results demonstrate that neurons in the CNS have the capability to generate C5a following ischemic stress, and this has the potential to activate their C5a receptors, with deleterious consequences.
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Affiliation(s)
- Dale Pavlovski
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia
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