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Liu Y, Li S, Liu B, Zhang J, Wang C, Feng L. Maternal urban particulate matter (SRM 1648a) exposure disrupted the cellular immune homeostasis during early life: The potential attribution of altered placental transcriptome profile. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169432. [PMID: 38135080 DOI: 10.1016/j.scitotenv.2023.169432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 12/11/2023] [Accepted: 12/14/2023] [Indexed: 12/24/2023]
Abstract
Ambient fine particular matter (PM2.5) exposure has been associated with numerous adverse effects including triggering functional disorders of the placenta and inducing immune imbalance in offspring. However, how maternal PM2.5 exposure impacts immune development during early life is not fully understood. In the current study, we exposed mice with low-, middle-, and high-dose PM2.5 during pregnancy to investigate the potential link between the transcriptional changes in the placenta and immune imbalance in mice offspring induced by PM2.5 exposures. Using flow cytometry, we found that the proportions of B cells, CD3+CD4+ T cells, CD3+CD8+ T cells, and macrophage (Mφ) cells were altered in the blood of PM2.5-exposed mice pups but not dendritic cells (DCs) and natural killer cells (NKs). Using bulk RNA sequencing, we found that PM2.5 exposure altered the transcriptional profile which indicated an inhibition of the complement and coagulation cascades in the placenta. Weighted gene co-expression network analysis (WGCNA) revealed the potential crosstalk between the perturbation of placental gene expression and the changes of immune cell subsets in pups on postnatal day 10 (PND10). Specifically, WGCNA identified a cluster of genes including Defb15, Defb20, Defb25, Cst8, Cst12, and Adam7 that might regulate the core immune cell types in PND10 pups. Although the underlying mechanisms of how maternal PM2.5 exposure induces peripheral lymphocyte disturbance in offspring still remain much unknown, our findings here shed light on the potential role of placental dysfunction in these adverse effects.
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Affiliation(s)
- Yongjie Liu
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, PR China
| | - Shuman Li
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, PR China
| | - Bin Liu
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, PR China
| | - Jun Zhang
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, PR China
| | - Cuiping Wang
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, PR China; Department of Maternal and Child Health, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan 250012, PR China.
| | - Liping Feng
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, PR China; Department of Obstetrics and Gynecology, Duke University School of Medicine, Durham, USA.
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2
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Xie C, Hu J, Cheng Y, Yao Z. Researches on cognitive sequelae of burn injury: Current status and advances. Front Neurosci 2022; 16:1026152. [PMID: 36408414 PMCID: PMC9672468 DOI: 10.3389/fnins.2022.1026152] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 10/20/2022] [Indexed: 09/29/2023] Open
Abstract
Burn injury is a devastating disease with high incidence of disability and mortality. The cognitive dysfunctions, such as memory defect, are the main neurological sequelae influencing the life quality of burn-injured patients. The post-burn cognitive dysfunctions are related to the primary peripheral factors and the secondary cerebral inflammation, resulting in the destruction of blood-brain barrier (BBB), as is shown on Computed Tomography (CT) and magnetic resonance imaging examinations. As part of the neurovascular unit, BBB is vital to the nutrition and homeostasis of the central nervous system (CNS) and undergoes myriad alterations after burn injury, causing post-burn cognitive defects. The diagnosis and treatment of cognitive dysfunctions as burn injury sequelae are of great importance. In this review, we address the major manifestations and interventions of post-burn cognitive defects, as well as the mechanisms involved in memory defect, including neuroinflammation, destruction of BBB, and hormone imbalance.
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Affiliation(s)
- Chenchen Xie
- Department of Neurology, Affiliated Hospital and Clinical Medical College of Chengdu University, Chengdu, China
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jun Hu
- Department of Neurology, First Affiliated Hospital of Army Medical University, Chongqing, China
| | - Yong Cheng
- Department of Neurology, General Hospital of Central Theater Command of PLA, Wuhan, China
| | - Zhongxiang Yao
- Department of Physiology, Army Medical University, Chongqing, China
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3
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Jiang Y, Chen Y, Sun H, Zhang X, He L, Li J, Zhao G, Sun S. MERS-CoV infection causes brain damage in human DPP4-transgenic mice through complement-mediated inflammation. J Gen Virol 2021; 102. [PMID: 34704923 PMCID: PMC8604193 DOI: 10.1099/jgv.0.001667] [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] [Indexed: 01/04/2023] Open
Abstract
The highly pathogenic Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a severe respiratory virus. Recent reports indicate additional central nervous system (CNS) involvement. In this study, human DPP4 transgenic mice were infected with MERS-CoV, and viral antigens were first detected in the midbrain-hindbrain 4 days post-infection, suggesting the virus may enter the brainstem via peripheral nerves. Neurons and astrocytes throughout the brain were infected, followed by damage of the blood brain barrier (BBB), as well as microglial activation and inflammatory cell infiltration, which may be caused by complement activation based on the observation of deposition of complement activation product C3 and high expression of C3a receptor (C3aR) and C5a receptor (C5aR1) in neurons and glial cells. It may be concluded that these effects were mediated by complement activation in the brain, because of their reduction resulted from the treatment with mouse C5aR1-specific mAb. Such mAb significantly reduced nucleoprotein expression, suppressed microglial activation and decreased activation of caspase-3 in neurons and p38 phosphorylation in the brain. Collectively, these results suggest that MERS-CoV infection of CNS triggers complement activation, leading to inflammation-mediated damage of brain tissue, and regulating of complement activation could be a promising intervention and adjunctive treatment for CNS injury by MERS-CoV and other coronaviruses.
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Affiliation(s)
- Yuting Jiang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Yuehong Chen
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Hong Sun
- Department of Basic Medical Sciences, North China University of Science and Technology, Tangshan 063210, PR China
| | - Xiaolu Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Lei He
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Jiangfan Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Guangyu Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Shihui Sun
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
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4
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Chen J, Sun ZH, Chen LY, Xu F, Zhao YP, Li GQ, Tang M, Li Y, Zheng QY, Wang SF, Yang XH, Wu YZ, Xu GL. C5aR deficiency attenuates the breast cancer development via the p38/p21 axis. Aging (Albany NY) 2020; 12:14285-14299. [PMID: 32669478 PMCID: PMC7425439 DOI: 10.18632/aging.103468] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 05/01/2020] [Indexed: 11/25/2022]
Abstract
Emerging evidence has shown activation of the complement component C5 to C5a in cancer tissues and C5aR expression in breast cancer cells relates to the tumor development and poor prognosis, suggesting the involvement of complement C5a/C5aR pathway in the breast cancer pathogenesis. In this study, we found that as compared to the non-tumoral tissues, both C5aR and MAPK/p38 showed an elevated expression, but p21/p-p21 showed lower expression, in the tumoral tissues of breast cancer patients. Mice deficient in C5aR or mice treated with the C5aR antagonist exhibited attenuation of breast cancer growth and reduction in the p38/p-p38 expression, but increase in p21/p-p21 expression, in the tumor tissues. Pre-treatment of the breast cancer cells with recombinant C5a resulted in reduced p21 expression, and MAPK/p38 inhibitors prevented C5a-induced reduction in p21 expression, suggesting the involvement of the MAPK/p38 signaling pathway in the C5a/C5aR-mediated suppression of p21/p-p21 expression. These results provide evidence that breast cancer development may rely on C5a/C5aR interaction, for which MAPK/p38 pathway participate in down-regulating the p21 expression. Inhibition of C5a/C5aR pathway is expected to be helpful for the treatment of patients with breast cancer.
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Affiliation(s)
- Jian Chen
- Department of Immunology, Army Medical University (Third Military Medical University), Chongqing 400038, China
| | - Zi-Han Sun
- Breast Disease Center, Guiqian International General Hospital, Guiyang 550000, China
| | - Li-Ying Chen
- Institute of Cancer, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing 400037, China
| | - Feng Xu
- Department of Immunology, Army Medical University (Third Military Medical University), Chongqing 400038, China
| | - Yun-Pei Zhao
- Department of Immunology, Army Medical University (Third Military Medical University), Chongqing 400038, China
| | - Gui-Qing Li
- Department of Immunology, Army Medical University (Third Military Medical University), Chongqing 400038, China
| | - Ming Tang
- Urinary Nephropathy Center, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400065, China
| | - You Li
- Department of ICU, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing 400038, China
| | - Quan-You Zheng
- Department of Urology, 958 Hospital, Army Medical University (Third Military Medical University), Chongqing 400020, China
| | - Shu-Feng Wang
- Department of Immunology, Army Medical University (Third Military Medical University), Chongqing 400038, China
| | - Xin-Hua Yang
- Breast Disease Center, Guiqian International General Hospital, Guiyang 550000, China
| | - Yu-Zhang Wu
- Department of Immunology, Army Medical University (Third Military Medical University), Chongqing 400038, China
| | - Gui-Lian Xu
- Department of Immunology, Army Medical University (Third Military Medical University), Chongqing 400038, China
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Stahel PF, Barnum SR. Complement Inhibition in Coronavirus Disease (COVID)-19: A Neglected Therapeutic Option. Front Immunol 2020; 11:1661. [PMID: 32733489 PMCID: PMC7358522 DOI: 10.3389/fimmu.2020.01661] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 06/22/2020] [Indexed: 01/08/2023] Open
Affiliation(s)
- Philip F Stahel
- Department of Specialty Medicine, College of Osteopathic Medicine, Rocky Vista University, Parker, CO, United States
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Soluble terminal complement activation fragment sC5b-9: a new serum biomarker for traumatic brain injury? Eur J Trauma Emerg Surg 2020; 47:1491-1497. [DOI: 10.1007/s00068-020-01407-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 05/18/2020] [Indexed: 12/19/2022]
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Dinet V, Petry KG, Badaut J. Brain-Immune Interactions and Neuroinflammation After Traumatic Brain Injury. Front Neurosci 2019; 13:1178. [PMID: 31780883 PMCID: PMC6861304 DOI: 10.3389/fnins.2019.01178] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 10/18/2019] [Indexed: 01/04/2023] Open
Abstract
Traumatic brain injury (TBI) is the principal cause of death and disability in children and young adults. Clinical and preclinical research efforts have been carried out to understand the acute, life-threatening pathophysiological events happening after TBI. In the past few years, however, it was recognized that TBI causes significant morbidity weeks, months, or years after the initial injury, thereby contributing substantially to the overall burden of TBI and the decrease of life expectancy in these patients. Long-lasting sequels of TBI include cognitive decline/dementia, sensory-motor dysfunction, and psychiatric disorders, and most important for patients is the need for socio-economic rehabilitation affecting their quality of life. Cerebrovascular alterations have been described during the first week after TBI for direct consequence development of neuroinflammatory process in relation to brain edema. Within the brain-immune interactions, the complement system, which is a family of blood and cell surface proteins, participates in the pathophysiology process. In fact, the complement system is part of the primary defense and clearance component of innate and adaptive immune response. In this review, the complement activation after TBI will be described in relation to the activation of the microglia and astrocytes as well as the blood-brain barrier dysfunction during the first week after the injury. Considering the neuroinflammatory activity as a causal element of neurological handicaps, some major parallel lines of complement activity in multiple sclerosis and Alzheimer pathologies with regard to cognitive impairment will be discussed for chronic TBI. A better understanding of the role of complement activation could facilitate the development of new therapeutic approaches for TBI.
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Affiliation(s)
- Virginie Dinet
- INSERM U1029, Angiogenesis and Neuroinflammation Group, University of Bordeaux, Bordeaux, France
| | - Klaus G. Petry
- INSERM U1029, Angiogenesis and Neuroinflammation Group, University of Bordeaux, Bordeaux, France
| | - Jerome Badaut
- CNRS UMR 5287, INCIA, Brain molecular Imaging Team, University of Bordeaux, Bordeaux, France
- Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, United States
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Satyam A, Graef ER, Lapchak PH, Tsokos MG, Dalle Lucca JJ, Tsokos GC. Complement and coagulation cascades in trauma. Acute Med Surg 2019; 6:329-335. [PMID: 31592318 PMCID: PMC6773636 DOI: 10.1002/ams2.426] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 03/19/2019] [Indexed: 01/12/2023] Open
Abstract
Trauma remains a major cause of death throughout the world, especially for patients younger than 45 years. Due to rapid advances in clinical management, both in the acute and prehospital settings, trauma patients survive devastating injuries at unprecedented rates. However, these patients can often face life threatening complications that stem from the robust innate immune response induced by severe hemorrhage, leading to further tissue injury rather than repair. The complement and coagulation cascades are key mediators in this disordered reaction, which includes the development of trauma‐induced coagulopathy. There is increasing evidence that cross‐talk between these two pathways allows rapid amplification of their otherwise targeted responses and contributes to overwhelming and prolonged systemic inflammation. In this article, we summarize the initial steps of innate immune response to trauma and review the complex complement and coagulation cascades, as well as how they interact with each other. Despite progress in understanding these cascades, effective therapeutic targets have yet to be found and further research is needed both to improve survival rates as well as decrease associated morbidity.
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Affiliation(s)
- Abhigyan Satyam
- Department of Medicine Beth Israel Deaconess Medical Center Harvard Medical School Boston Massachusetts
| | - Elizabeth R Graef
- Department of Medicine Beth Israel Deaconess Medical Center Harvard Medical School Boston Massachusetts
| | - Peter H Lapchak
- Department of Medicine Beth Israel Deaconess Medical Center Harvard Medical School Boston Massachusetts
| | - Maria G Tsokos
- Department of Medicine Beth Israel Deaconess Medical Center Harvard Medical School Boston Massachusetts
| | | | - George C Tsokos
- Department of Medicine Beth Israel Deaconess Medical Center Harvard Medical School Boston Massachusetts
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Wang Y, Li SY, Shen S, Wang J. Protecting neurons from cerebral ischemia/reperfusion injury via nanoparticle-mediated delivery of an siRNA to inhibit microglial neurotoxicity. Biomaterials 2018; 161:95-105. [PMID: 29421566 DOI: 10.1016/j.biomaterials.2018.01.039] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 01/18/2018] [Accepted: 01/25/2018] [Indexed: 01/14/2023]
Abstract
Complement component C3 (C3) plays a central role in microglial neurotoxicity following cerebral ischemia/reperfusion (I/R) injury. In this study, we focused on the role of nanoparticles loaded with C3 siRNA (NPsiC3) in inhibiting microglial neurotoxicity after brain (I/R) injury. NPsiC3 inhibited the hypoxia/re-oxygenation-induced increase in C3 expression in microglia in vitro. Importantly, treatment with NPsiC3 decreased C3b deposition on neurons and reduced microglia-mediated neuronal damage under hypoxia/re-oxygen conditions. Nanoparticles could effectively deliver C3-siRNA from the blood into ischemic penumbra across the blood-brain barrier (BBB) and significantly decrease C3 expression in microglia and ischemic brain tissue, while reducing the number of infiltrating inflammatory cells and the concentration of pro-inflammatory factors in the penumbra. Furthermore, NPsiC3 also prevented neuronal apoptosis, reduced the volume of the ischemic zone, and substantially improved functional recovery after I/R injury. Therefore, the NPsiC3-induced inhibition of microglial neurotoxicity represents a novel therapeutic strategy for treating brain I/R injury.
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Affiliation(s)
- Ye Wang
- Department of Neurology, Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, PR China
| | - Shi-Yong Li
- Department of Neurology, Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, PR China; Department of Cardiology, Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, PR China.
| | - Song Shen
- Institutes for Life Sciences, School of Biomedical Science and Engineering, South China University of Technology, Guangzhou, Guangdong 510006, PR China; National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou, Guangdong 510006, PR China
| | - Jun Wang
- Institutes for Life Sciences, School of Biomedical Science and Engineering, South China University of Technology, Guangzhou, Guangdong 510006, PR China; National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou, Guangdong 510006, PR China; Research Institute for Food Nutrition and Human Health, Guangzhou, Guangdong 510006, PR China.
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10
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Ramos TN, Arynchyna AA, Blackburn TE, Barnum SR, Johnston JM. Soluble membrane attack complex is diagnostic for intraventricular shunt infection in children. JCI Insight 2016; 1:e87919. [PMID: 27699221 DOI: 10.1172/jci.insight.87919] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Children treated with cerebrospinal fluid (CSF) shunts to manage hydrocephalus frequently develop shunt failure and/or infections, conditions that present with overlapping symptoms. The potential life-threatening nature of shunt infections requires rapid diagnosis; however, traditional microbiology is time consuming, expensive, and potentially unreliable. We set out to identify a biomarker that would identify shunt infection. METHODS CSF was assayed for the soluble membrane attack complex (sMAC) by ELISA in patients with suspected shunt failure or infection. CSF was obtained at the time of initial surgical intervention. Statistical analysis was performed to assess the diagnostic potential of sMAC in pyogenic-infected versus noninfected patients. RESULTS Children with pyogenic shunt infection had significantly increased sMAC levels compared with noninfected patients (3,211 ± 1,111 ng/ml vs. 26 ± 3.8 ng/ml, P = 0.0001). In infected patients undergoing serial CSF draws, sMAC levels were prognostic for both positive and negative clinical outcomes. Children with delayed, broth-only growth of commensal organisms (P. acnes, S. epidermidis, etc.) had the lowest sMAC levels (7.96 ± 1.7 ng/ml), suggesting contamination rather than shunt infection. CONCLUSION Elevated CSF sMAC levels are both sensitive and specific for diagnosing pyogenic shunt infection and may serve as a useful prognostic biomarker during recovery from infection. FUNDING This work was supported in part by the Impact Fund of Children's of Alabama.
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Affiliation(s)
| | - Anastasia A Arynchyna
- Division of Pediatric Neurosurgery, Department of Neurosurgery, Children's of Alabama
| | | | - Scott R Barnum
- Department of Microbiology.,Department of Neurology, University of Alabama at Birmingham (UAB), Birmingham, Alabama, USA
| | - James M Johnston
- Division of Pediatric Neurosurgery, Department of Neurosurgery, Children's of Alabama
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11
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Brennan FH, Kurniawan ND, Vukovic J, Bartlett PF, Käsermann F, Arumugam TV, Basta M, Ruitenberg MJ. IVIg attenuates complement and improves spinal cord injury outcomes in mice. Ann Clin Transl Neurol 2016; 3:495-511. [PMID: 27386499 PMCID: PMC4931715 DOI: 10.1002/acn3.318] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 04/20/2016] [Accepted: 04/21/2016] [Indexed: 12/22/2022] Open
Abstract
Objective Traumatic spinal cord injury (SCI) elicits immediate neural cell death, axonal damage, and disruption of the blood–spinal cord barrier, allowing circulating immune cells and blood proteins into the spinal parenchyma. The inflammatory response to SCI involves robust complement system activation, which contributes to secondary injury and impairs neurological recovery. This study aimed to determine whether intravenous immunoglobulin (IVIg), an FDA‐approved treatment for inflammatory conditions, can scavenge complement activation products and improve recovery from contusive SCI. Methods We used functional testing, noninvasive imaging, and detailed postmortem analysis to assess whether IVIg therapy is effective in a mouse model of severe contusive SCI. Results IVIg therapy at doses of 0.5–2 g/kg improved the functional and histopathological outcomes from SCI, conferring protection against lesion enlargement, demyelination, central canal dilation, and axonal degeneration. The benefits of IVIg were detectable through noninvasive diffusion tensor imaging (DTI), with IVIg treatment counteracting the progressive SCI‐induced increase in radial diffusivity (RD) in white matter. Diffusion indices significantly correlated with the functional performance of individual mice and accurately predicted the degree of myelin preservation. Further experiments revealed that IVIg therapy reduced the presence of complement activation products and phagocytically active macrophages at the lesion site, providing insight as to its mechanisms of action. Interpretation Our findings highlight the potential of using IVIg as an immunomodulatory treatment for SCI, and the value of DTI to assess tissue damage and screen for the efficacy of candidate intervention strategies in preclinical models of SCI, both quantitatively and noninvasively.
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Affiliation(s)
- Faith H Brennan
- School of Biomedical Sciences The University of Queensland Brisbane 4072 Australia
| | - Nyoman D Kurniawan
- Centre for Advanced Imaging The University of Queensland Brisbane 4072 Australia
| | - Jana Vukovic
- School of Biomedical Sciences The University of Queensland Brisbane 4072 Australia; Queensland Brain Institute The University of Queensland Brisbane 4072 Australia
| | - Perry F Bartlett
- Queensland Brain Institute The University of Queensland Brisbane 4072 Australia
| | | | - Thiruma V Arumugam
- Department of Physiology Yong Loo Lin School of Medicine National University of Singapore 117597 Singapore
| | - Milan Basta
- BioVisions Inc. 9012 Wandering Trail Dr Potomac Maryland 20854 USA
| | - Marc J Ruitenberg
- School of Biomedical Sciences The University of Queensland Brisbane 4072 Australia; Queensland Brain Institute The University of Queensland Brisbane 4072 Australia; Trauma Critical Care and Recovery Brisbane Diamantina Health Partners The University of Queensland Brisbane 4072 Australia
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12
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Rich MC, Keene CN, Neher MD, Johnson K, Yu ZX, Ganivet A, Holers VM, Stahel PF. Site-targeted complement inhibition by a complement receptor 2-conjugated inhibitor (mTT30) ameliorates post-injury neuropathology in mouse brains. Neurosci Lett 2016; 617:188-94. [PMID: 26892188 DOI: 10.1016/j.neulet.2016.02.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Revised: 02/10/2016] [Accepted: 02/12/2016] [Indexed: 11/26/2022]
Abstract
Intracerebral complement activation after severe traumatic brain injury (TBI) leads to a cascade of neuroinflammatory pathological sequelae that propagate host-mediated secondary brain injury and adverse outcomes. There are currently no specific pharmacological agents on the market to prevent or mitigate the development of secondary cerebral insults after TBI. A novel chimeric CR2-fH compound (mTT30) provides targeted inhibition of the alternative complement pathway at the site of tissue injury. This experimental study was designed to test the neuroprotective effects of mTT30 in a mouse model of closed head injury. The administration of 500 μg mTT30 i.v. at 1 h, 4 h and 24 h after head injury attenuated complement C3 deposition in injured brains, reduced the extent of neuronal cell death, and decreased post-injury microglial activation, compared to vehicle-injected placebo controls. These data imply that site-targeted alternative pathway complement inhibition may represent a new promising therapeutic avenue for the future management of severe TBI.
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Affiliation(s)
- Megan C Rich
- Department of Orthopaedic Surgery, Denver Health Medical Center and University of Colorado School of Medicine, Denver, CO 80204, USA
| | - Chesleigh N Keene
- Department of Orthopaedic Surgery, Denver Health Medical Center and University of Colorado School of Medicine, Denver, CO 80204, USA
| | - Miriam D Neher
- Department of Orthopaedic Surgery, Denver Health Medical Center and University of Colorado School of Medicine, Denver, CO 80204, USA
| | | | - Zhao-Xue Yu
- Alexion Pharmaceuticals, Cheshire, CT 06410, USA
| | - Antoine Ganivet
- Department of Orthopaedic Surgery, Denver Health Medical Center and University of Colorado School of Medicine, Denver, CO 80204, USA
| | - V Michael Holers
- Department of Medicine and Department of Immunology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Philip F Stahel
- Department of Orthopaedic Surgery, Denver Health Medical Center and University of Colorado School of Medicine, Denver, CO 80204, USA; Department of Neurosurgery, University of Colorado School of Medicine, Denver, CO 80204, USA.
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13
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Management strategies for acute spinal cord injury: current options and future perspectives. Curr Opin Crit Care 2013; 18:651-60. [PMID: 23104069 DOI: 10.1097/mcc.0b013e32835a0e54] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
PURPOSE OF REVIEW Spinal cord injury is a devastating acute neurological condition with loss of function and poor long-term prognosis. This review summarizes current management strategies and innovative concepts on the horizon. RECENT FINDINGS The routine use of steroids in patients with spinal cord injuries has been largely abandoned and considered a 'harmful standard of care'. Prospective trials have shown that early spine stabilization within 24 h results in decreased secondary complication rates. Neuronal plasticity and axonal regeneration in the adult spinal cord are limited due to myelin-associated inhibitory molecules, such as Nogo-A. The experimental inhibition of Nogo-A ameliorates axonal sprouting and functional recovery in animal models. SUMMARY General management strategies for acute spinal cord injury consist of protection of airway, breathing, oxygenation and control of blood loss with maintenance of blood pressure. Unstable spine fractures should be stabilized early to allow unrestricted mobilization of patients with spinal cord injuries and to decrease preventable complications. Steroids are largely considered obsolete and have been abandoned in clinical guidelines. Nogo-A represents a promising new pharmacological target to promote sprouting of injured axons and restore function. Prospective clinical trials of Nogo-A inhibition in patients with spinal cord injuries are currently under way.
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14
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Qing XY, Zhang CH, Li LL, Ji P, Ma S, Wan HL, Wang ZR, Zou J, Yang SY. Retrieving novel C5aR antagonists using a hybrid ligand-based virtual screening protocol based on SVM classification and pharmacophore models. J Biomol Struct Dyn 2013; 31:215-23. [DOI: 10.1080/07391102.2012.698245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Ramos TN, Darley MM, Weckbach S, Stahel PF, Tomlinson S, Barnum SR. The C5 convertase is not required for activation of the terminal complement pathway in murine experimental cerebral malaria. J Biol Chem 2012; 287:24734-8. [PMID: 22689574 DOI: 10.1074/jbc.c112.378364] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Cerebral malaria (CM) is the most severe manifestation of clinical malaria syndromes and has a high fatality rate especially in the developing world. Recent studies demonstrated that C5(-/-) mice are resistant to experimental CM (ECM) and that protection was due to the inability to form the membrane attack complex. Unexpectedly, we observed that C4(-/-) and factor B(-/-) mice were fully susceptible to disease, indicating that activation of the classical or alternative pathways is not required for ECM. C3(-/-) mice were also susceptible to ECM, indicating that the canonical C5 convertases are not required for ECM development and progression. Abrogation of ECM by treatment with anti-C9 antibody and detection of C5a in serum of C3(-/-) mice confirmed that C5 activation occurs in ECM independent of C5 convertases. Our data indicate that activation of C5 in ECM likely occurs via coagulation enzymes of the extrinsic protease pathway.
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Affiliation(s)
- Theresa N Ramos
- Department of Microbiology, University of Alabama, Birmingham, Alabama 35294, USA
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Weckbach S, Neher M, Losacco JT, Bolden AL, Kulik L, Flierl MA, Bell SE, Holers VM, Stahel PF. Challenging the role of adaptive immunity in neurotrauma: Rag1(-/-) mice lacking mature B and T cells do not show neuroprotection after closed head injury. J Neurotrauma 2012; 29:1233-42. [PMID: 22335783 DOI: 10.1089/neu.2011.2169] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The role of adaptive immunity in contributing to post-traumatic neuroinflammation and neuropathology after head injury remains largely unexplored. The present study was designed to investigate the pathophysiological sequelae of closed head injury in Rag1(-/-) mice devoid of mature B and T lymphocytes. C57BL/6 wild-type and Rag1(-/-) mice were subjected to experimental closed head injury, using a standardized weight-drop device. Outcome parameters consisted of neurological scoring, quantification of blood-brain barrier (BBB) function, measurement of inflammatory markers and mediators of apoptosis in serum and brain tissue, and assessment of neuronal cell death, astrogliosis, and tissue destruction. There was no difference between wild-type and Rag1(-/-) mice with regard to injury severity and neurological impairment for up to 7 days after head injury. The extent of BBB dysfunction was in a similar range for both groups. Quantification of complement activation fragments in serum revealed significantly attenuated C3a levels in Rag1(-/-) mice compared to wild-type animals. In contrast, the levels of pro- and anti-inflammatory cytokines and pro-apoptotic and anti-apoptotic mediators remained in a similar range for both groups, and the histological analysis of brain sections did not reveal a difference in reactive astrogliosis, tissue destruction, and neuronal cell death in Rag1(-/-) compared to wild-type mice. These findings suggest that adaptive immunity is not of crucial importance for initiating and sustaining the inflammatory neuropathology after closed head injury. The attenuated extent of post-traumatic complement activation seen in Rag1(-/-) mice implies a cross-talk between innate and adaptive immune responses, which requires further investigation in future studies.
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Affiliation(s)
- Sebastian Weckbach
- Department of Orthopaedics, Denver Health Medical Center, University of Colorado School of Medicine, Denver, Colorado 80204, USA
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Neher MD, Weckbach S, Flierl MA, Huber-Lang MS, Stahel PF. Molecular mechanisms of inflammation and tissue injury after major trauma--is complement the "bad guy"? J Biomed Sci 2011; 18:90. [PMID: 22129197 PMCID: PMC3247859 DOI: 10.1186/1423-0127-18-90] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Accepted: 11/30/2011] [Indexed: 02/07/2023] Open
Abstract
Trauma represents the leading cause of death among young people in industrialized countries. Recent clinical and experimental studies have brought increasing evidence for activation of the innate immune system in contributing to the pathogenesis of trauma-induced sequelae and adverse outcome. As the "first line of defense", the complement system represents a potent effector arm of innate immunity, and has been implicated in mediating the early posttraumatic inflammatory response. Despite its generic beneficial functions, including pathogen elimination and immediate response to danger signals, complement activation may exert detrimental effects after trauma, in terms of mounting an "innocent bystander" attack on host tissue. Posttraumatic ischemia/reperfusion injuries represent the classic entity of complement-mediated tissue damage, adding to the "antigenic load" by exacerbation of local and systemic inflammation and release of toxic mediators. These pathophysiological sequelae have been shown to sustain the systemic inflammatory response syndrome after major trauma, and can ultimately contribute to remote organ injury and death. Numerous experimental models have been designed in recent years with the aim of mimicking the inflammatory reaction after trauma and to allow the testing of new pharmacological approaches, including the emergent concept of site-targeted complement inhibition. The present review provides an overview on the current understanding of the cellular and molecular mechanisms of complement activation after major trauma, with an emphasis of emerging therapeutic concepts which may provide the rationale for a "bench-to-bedside" approach in the design of future pharmacological strategies.
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Affiliation(s)
- Miriam D Neher
- Department of Orthopaedic Surgery, University of Colorado Denver, School of Medicine, Denver Health Medical Center, 777 Bannock Street, Denver, CO 80204, USA
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Esposito E, Cuzzocrea S. Targeting the peroxisome proliferator-activated receptors (PPARs) in spinal cord injury. Expert Opin Ther Targets 2011; 15:943-59. [DOI: 10.1517/14728222.2011.581231] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Flierl MA, Gaudiani JL, Sabel AL, Long CS, Stahel PF, Mehler PS. Complement C3 serum levels in anorexia nervosa: a potential biomarker for the severity of disease? Ann Gen Psychiatry 2011; 10:16. [PMID: 21542928 PMCID: PMC3110119 DOI: 10.1186/1744-859x-10-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 05/04/2011] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Anorexia nervosa carries the highest mortality rate of any psychiatric disorder. Even the most critically ill anorexic patients may present with normal 'standard' laboratory values, underscoring the need for a new sensitive biomarker. The complement cascade, a major component of innate immunity, represents a driving force in the pathophysiology of multiple inflammatory disorders. The role of complement in anorexia nervosa remains poorly understood. The present study was designed to evaluate the role of complement C3 levels, the extent of complement activation and of complement hemolytic activity in serum, as potential new biomarkers for the severity of anorexia nervosa. PATIENTS AND METHODS This was a prospective cohort study on 14 patients with severe anorexia nervosa, as defined by a body mass index (BMI) <14 kg/m2. Serum samples were obtained in a biweekly manner until hospital discharge. A total of 17 healthy subjects with normal BMI values served as controls. The serum levels of complement C3, C3a, C5a, sC5b-9, and of the 50% hemolytic complement activity (CH50) were quantified and correlated with the BMIs of patients and control subjects. RESULTS Serum C3 levels were significantly lower in patients with anorexia nervosa than in controls (median 3.7 (interquartile range (IQR) 2.5-4.9) vs 11.4 (IQR 8.9-13.7, P <0.001). In contrast, complement activation fragments and CH50 levels were not significantly different between the two groups. There was a strong correlation between index C3 levels and BMI (Spearman correlation coefficient = 0.71, P <0.001). CONCLUSIONS Complement C3 serum levels may represent a sensitive new biomarker for monitoring the severity of disease in anorexia nervosa. The finding from this preliminary pilot study will require further investigation in future prospective large-scale multicenter trials.
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Affiliation(s)
- Michael A Flierl
- Department of Internal Medicine, Denver Health Medical Center, Denver, CO, USA.
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Stahel PF, Flierl MA. Targeted modulation of the neuroinflammatory response after spinal cord injury: the ongoing quest for the "holy grail". THE AMERICAN JOURNAL OF PATHOLOGY 2010; 177:2685-7. [PMID: 20952586 DOI: 10.2353/ajpath.2010.100408] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This Commentary discusses the role of inflammation after spinal cord injury.
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Affiliation(s)
- Philip F Stahel
- Department of Orthopaedic Surgery, University of Colorado Denver, School of Medicine Denver Health Medical Center, 777 Bannock Street, Denver, CO 80204, USA.
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Flierl MA, Stahel PF, Touban BM, Beauchamp KM, Morgan SJ, Smith WR, Ipaktchi KR. Bench-to-bedside review: Burn-induced cerebral inflammation--a neglected entity? CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2009; 13:215. [PMID: 19638180 PMCID: PMC2717412 DOI: 10.1186/cc7794] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Severe burn injury remains a major burden on patients and healthcare systems. Following severe burns, the injured tissues mount a local inflammatory response aiming to restore homeostasis. With excessive burn load, the immune response becomes disproportionate and patients may develop an overshooting systemic inflammatory response, compromising multiple physiological barriers in the lung, kidney, liver, and brain. If the blood–brain barrier is breached, systemic inflammatory molecules and phagocytes readily enter the brain and activate sessile cells of the central nervous system. Copious amounts of reactive oxygen species, reactive nitrogen species, proteases, cytokines/chemokines, and complement proteins are being released by these inflammatory cells, resulting in additional neuronal damage and life-threatening cerebral edema. Despite the correlation between cerebral complications in severe burn victims with mortality, burn-induced neuroinflammation continues to fly under the radar as an underestimated entity in the critically ill burn patient. In this paper, we illustrate the molecular events leading to blood–brain barrier breakdown, with a focus on the subsequent neuroinflammatory changes leading to cerebral edema in patients with severe burns.
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Affiliation(s)
- Michael A Flierl
- Department of Orthopaedic Surgery, Denver Health Medical Center, University of Colorado School of Medicine, Denver, CO 80204, USA.
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Abstract
BACKGROUND This review summarizes promising approaches for the treatment of traumatic brain injury (TBI) that are in either preclinical or clinical trials. OBJECTIVE The pathophysiology underlying neurological deficits after TBI is described. An overview of select therapies for TBI with neuroprotective and neurorestorative effects is presented. METHODS A literature review of preclinical TBI studies and clinical TBI trials related to neuroprotective and neurorestorative therapeutic approaches is provided. RESULTS/CONCLUSION Nearly all Phase II/III clinical trials in neuroprotection have failed to show any consistent improvement in outcome for TBI patients. The next decade will witness an increasing number of clinical trials that seek to translate preclinical research discoveries to the clinic. Promising drug- or cell-based therapeutic approaches include erythropoietin and its carbamylated form, statins, bone marrow stromal cells, stem cells singularly or in combination or with biomaterials to reduce brain injury via neuroprotection and promote brain remodeling via angiogenesis, neurogenesis, and synaptogenesis with a final goal to improve functional outcome of TBI patients. In addition, enriched environment and voluntary physical exercise show promise in promoting functional outcome after TBI, and should be evaluated alone or in combination with other treatments as therapeutic approaches for TBI.
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Affiliation(s)
- Ye Xiong
- Henry Ford Health System, Department of Neurosurgery, Detroit, MI 48202, USA
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Flierl MA, Stahel PF, Rittirsch D, Huber-Lang M, Niederbichler AD, Hoesel LM, Touban BM, Morgan SJ, Smith WR, Ward PA, Ipaktchi K. Inhibition of complement C5a prevents breakdown of the blood-brain barrier and pituitary dysfunction in experimental sepsis. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2009; 13:R12. [PMID: 19196477 PMCID: PMC2688129 DOI: 10.1186/cc7710] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Revised: 01/12/2009] [Accepted: 02/06/2009] [Indexed: 12/12/2022]
Abstract
Introduction Septic encephalopathy secondary to a breakdown of the blood-brain barrier (BBB) is a known complication of sepsis. However, its pathophysiology remains unclear. The present study investigated the effect of complement C5a blockade in preventing BBB damage and pituitary dysfunction during experimental sepsis. Methods Using the standardised caecal ligation and puncture (CLP) model, Sprague-Dawley rats were treated with either neutralising anti-C5a antibody or pre-immune immunoglobulin (Ig) G as a placebo. Sham-operated animals served as internal controls. Results Placebo-treated septic rats showed severe BBB dysfunction within 24 hours, accompanied by a significant upregulation of pituitary C5a receptor and pro-inflammatory cytokine expression, although gene levels of growth hormone were significantly attenuated. The pathophysiological changes in placebo-treated septic rats were restored by administration of neutralising anti-C5a antibody to the normal levels of BBB and pituitary function seen in the sham-operated group. Conclusions Collectively, the neutralisation of C5a greatly ameliorated pathophysiological changes associated with septic encephalopathy, implying a further rationale for the concept of pharmacological C5a inhibition in sepsis.
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Affiliation(s)
- Michael A Flierl
- Department of Orthopaedic Surgery, Denver Health Medical Center, University of Colorado School of Medicine, Denver, CO 80204, USA.
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Stahel PF, Flierl MA, Morgan BP, Persigehl I, Stoll C, Conrad C, Touban BM, Smith WR, Beauchamp K, Schmidt OI, Ertel W, Leinhase I. Absence of the complement regulatory molecule CD59a leads to exacerbated neuropathology after traumatic brain injury in mice. J Neuroinflammation 2009; 6:2. [PMID: 19133139 PMCID: PMC2631471 DOI: 10.1186/1742-2094-6-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2008] [Accepted: 01/08/2009] [Indexed: 12/02/2022] Open
Abstract
Background Complement represents a crucial mediator of neuroinflammation and neurodegeneration after traumatic brain injury. The role of the terminal complement activation pathway, leading to generation of the membrane attack complex (MAC), has not been thoroughly investigated. CD59 is the major regulator of MAC formation and represents an essential protector from homologous cell injury after complement activation in the injured brain. Methods Mice deleted in the Cd59a gene (CD59a-/-) and wild-type littermates (n = 60) were subjected to focal closed head injury. Sham-operated (n = 60) and normal untreated mice (n = 14) served as negative controls. The posttraumatic neurological impairment was assessed for up to one week after trauma, using a standardized Neurological Severity Score (NSS). The extent of neuronal cell death was determined by serum levels of neuron-specific enolase (NSE) and by staining of brain tissue sections in TUNEL technique. The expression profiles of pro-apoptotic (Fas, FasL, Bax) and anti-apoptotic (Bcl-2) mediators were determined at the gene and protein level by real-time RT-PCR and Western blot, respectively. Results Clinically, the brain-injured CD59a-/- mice showed a significantly impaired neurological outcome within 7 days, as determined by a higher NSS, compared to wild-type controls. The NSE serum levels, an indirect marker of neuronal cell death, were significantly elevated in CD59a-/- mice at 4 h and 24 h after trauma, compared to wild-type littermates. At the tissue level, increased neuronal cell death and brain tissue destruction was detected by TUNEL histochemistry in CD59a-/- mice within 24 hours to 7 days after head trauma. The analysis of brain homogenates for potential mediators and regulators of cell death other than the complement MAC (Fas, FasL, Bax, Bcl-2) revealed no difference in gene expression and protein levels between CD59a-/- and wild-type mice. Conclusion These data emphasize an important role of CD59 in mediating protection from secondary neuronal cell death and further underscore the key role of the terminal complement pathway in the pathophysiology of traumatic brain injury. The exact mechanisms of complement MAC-induced secondary neuronal cell death after head injury require further investigation.
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Affiliation(s)
- Philip F Stahel
- Department of Orthopedic Surgery, Denver Health Medical Center, University of Colorado School of Medicine, Denver, CO 80204, USA.
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Alexander JJ, Anderson AJ, Barnum SR, Stevens B, Tenner AJ. The complement cascade: Yin-Yang in neuroinflammation--neuro-protection and -degeneration. J Neurochem 2008; 107:1169-87. [PMID: 18786171 DOI: 10.1111/j.1471-4159.2008.05668.x] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The complement cascade has long been recognized to play a key role in inflammatory and degenerative diseases. It is a 'double edged' sword as it is necessary to maintain health, yet can have adverse effects when unregulated, often exacerbating disease. The contrasting effects of complement, depending on whether in a setting of health or disease, is the price paid to achieve flexibility in scope and degree of a protective response for the host from infection and injury. Loss or even decreased efficiency of critical regulatory control mechanisms can result in aggravated inflammation and destruction of self-tissue. The role of the complement cascade is poorly understood in the nervous system and neurological disorders. Novel studies have demonstrated that the expression of complement proteins in brain varies in different cell types and the effects of complement activation in various disease settings appear to differ. Understanding the functioning of this cascade is essential, as it has therapeutic implications. In this review, we will attempt to provide insight into how this complex cascade functions and to identify potential strategic targets for therapeutic intervention in chronic diseases as well as acute injury in the CNS.
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Schmidt OI, Leinhase I, Hasenboehler E, Morgan SJ, Stahel PF. [The relevance of the inflammatory response in the injured brain]. DER ORTHOPADE 2007; 36:248, 250-8. [PMID: 17333066 DOI: 10.1007/s00132-007-1061-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Research efforts in recent years have defined traumatic brain injury (TBI) as a predominantly immunological and inflammatory disorder. This perception is based on the fact that the overwhelming neuroinflammatory response in the injured brain contributes to the development of posttraumatic edema and to neuropathological sequelae which are, in large part, responsible for the adverse outcome. While the "key" mediators of neuroinflammation, such as the cytokine cascade and the complement system, have been clearly defined by studies in experimental TBI models, their exact pathways of interaction and pathophysiological implications remain to be further elucidated. This lack of knowledge is partially due to the concept of a "dual role" of the neuroinflammatory response after TBI. This notion implies that specific inflammatory molecules may mediate diverse functions depending on their local concentration and kinetics of expression in the injured brain. The inflammation-induced effects range from beneficial aspects of neuroprotection to detrimental neurotoxicity. The lack of success in pushing anti-inflammatory therapeutic concepts from"bench to bedside" for patients with severe TBI strengthens the further need for advances in basic research on the molecular aspects of the neuroinflammatory network in the injured brain. The present review summarizes the current knowledge from experimental studies in this field of research and discusses potential future targets of investigation.
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Affiliation(s)
- O I Schmidt
- Zentrum für Traumatologie, Fachbereich Unfall- und Wiederherstellungschirurgie, Klinikum Sankt Georg, Leipzig
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Inhibition of the alternative complement activation pathway in traumatic brain injury by a monoclonal anti-factor B antibody: a randomized placebo-controlled study in mice. J Neuroinflammation 2007; 4:13. [PMID: 17474994 PMCID: PMC1867808 DOI: 10.1186/1742-2094-4-13] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Accepted: 05/02/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The posttraumatic response to traumatic brain injury (TBI) is characterized, in part, by activation of the innate immune response, including the complement system. We have recently shown that mice devoid of a functional alternative pathway of complement activation (factor B-/- mice) are protected from complement-mediated neuroinflammation and neuropathology after TBI. In the present study, we extrapolated this knowledge from studies in genetically engineered mice to a pharmacological approach using a monoclonal anti-factor B antibody. This neutralizing antibody represents a specific and potent inhibitor of the alternative complement pathway in mice. METHODS A focal trauma was applied to the left hemisphere of C57BL/6 mice (n = 89) using a standardized electric weight-drop model. Animals were randomly assigned to two treatment groups: (1) Systemic injection of 1 mg monoclonal anti-factor B antibody (mAb 1379) in 400 mul phosphate-buffered saline (PBS) at 1 hour and 24 hours after trauma; (2) Systemic injection of vehicle only (400 mul PBS), as placebo control, at identical time-points after trauma. Sham-operated and untreated mice served as additional negative controls. Evaluation of neurological scores and analysis of brain tissue specimens and serum samples was performed at defined time-points for up to 1 week. Complement activation in serum was assessed by zymosan assay and by murine C5a ELISA. Brain samples were analyzed by immunohistochemistry, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) histochemistry, and real-time RT-PCR. RESULTS The mAb 1379 leads to a significant inhibition of alternative pathway complement activity and to significantly attenuated C5a levels in serum, as compared to head-injured placebo-treated control mice. TBI induced histomorphological signs of neuroinflammation and neuronal apoptosis in the injured brain hemisphere of placebo-treated control mice for up to 7 days. In contrast, the systemic administration of an inhibitory anti-factor B antibody led to a substantial attenuation of cerebral tissue damage and neuronal cell death. In addition, the posttraumatic administration of the mAb 1379 induced a neuroprotective pattern of intracerebral gene expression. CONCLUSION Inhibition of the alternative complement pathway by posttraumatic administration of a neutralizing anti-factor B antibody appears to represent a new promising avenue for pharmacological attenuation of the complement-mediated neuroinflammatory response after head injury.
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Szalai AJ, Hu X, Adams JE, Barnum SR. Complement in experimental autoimmune encephalomyelitis revisited: C3 is required for development of maximal disease. Mol Immunol 2007; 44:3132-6. [PMID: 17353050 PMCID: PMC1986644 DOI: 10.1016/j.molimm.2007.02.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2007] [Revised: 02/02/2007] [Accepted: 02/05/2007] [Indexed: 10/23/2022]
Abstract
Complement per se has been shown to play an important role in demyelinating disease but controversy remains regarding the role of C3 in the development and progression of experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis. In this study, we used C3(-/-) mice to confirm previous findings that C3 is required for full development of EAE. Furthermore, C3(+/-) mice (with serum C3 levels 50% that of wild-type mice) developed EAE with a severity intermediate between wild-type and C3(-/-) mice. Importantly transfer of wild-type encephalitogenic T cells to C3(-/-) mice resulted in attenuated EAE. C3(-/-) mice with EAE had fewer CD4(+) and CD8(+) T cells in the CNS and 50% fewer of these cells produced IFN-gamma compared to wild-type mice. When treated with anti-CD3 antibody, CD4(+) T cells from wild-type and C3(-/-) mice had similar activation profiles as judged by IFN-gamma production and CD25 and CD69 expression, indicating there is no gross or intrinsic defect in T cells from C3(-/-) mice. T cells from primed C3(-/-) mice proliferated comparably to that of control T cells on re-stimulation with MOG peptide. Our results confirm a requirement for C3 for maximal development of EAE and suggest that receptors for C3-derived activation fragments might be a viable therapeutic target for prevention and treatment demyelinating disease.
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Affiliation(s)
- Alexander J. Szalai
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Xianzhen Hu
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Jillian E. Adams
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Scott R. Barnum
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL 35294
- *Corresponding Author: Dr. Scott R. Barnum, Department of Microbiology, University of Alabama at Birmingham, 845 19 St. S., BBRB/842, Birmingham, AL 35294. E-mail address:
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Sifringer M, Stefovska V, Endesfelder S, Stahel PF, Genz K, Dzietko M, Ikonomidou C, Felderhoff-Mueser U. Activation of caspase-1 dependent interleukins in developmental brain trauma. Neurobiol Dis 2007; 25:614-22. [PMID: 17188500 DOI: 10.1016/j.nbd.2006.11.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Revised: 10/31/2006] [Accepted: 11/04/2006] [Indexed: 11/27/2022] Open
Abstract
Focal mechanical cortical trauma triggers diffuse apoptotic neurodegeneration in the developing rat brain which is associated with invasion of brain tissue with inflammatory mediators. We hypothesized that caspase-1 and the two caspase-1-processed cytokines, interleukin (IL)-1beta and IL-18, are involved in trauma-induced neuronal cell death in the developing brain. 7-day-old Wistar rats or C57/BL6 mice were subjected to head trauma using a weight drop device. Animals were sacrificed at defined time points following trauma and brains were processed for histology and molecular analyses. Neuronal cell death in the immature brain peaked at 12-24 h and was accompanied by a marked increase of mRNA and protein levels for caspase-1, IL-1beta and IL-18 within 2 to 12 h following the injury. Caspase-1 levels were elevated for 72 h, whereas IL-1beta decreased earlier at 48 h. IL-18 remained high over a period of 3 days and decreased to normal levels by day 7 after the injury. Intraperitoneal injection of recombinant human IL-18-binding protein (IL-18BP), a specific inhibitor of IL-18, attenuated traumatic brain injury. Mice deficient in IL-18 (IL-18-/-) were protected against trauma-induced brain damage. These findings indicate that IL-18 is involved in trauma-induced neuronal cell death in the immature rodent brain and might serve as a potential therapeutic target.
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Affiliation(s)
- Marco Sifringer
- Department of Pediatric Neurology, Children's Hospital, Medical Faculty Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany
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Leinhase I, Holers VM, Thurman JM, Harhausen D, Schmidt OI, Pietzcker M, Taha ME, Rittirsch D, Huber-Lang M, Smith WR, Ward PA, Stahel PF. Reduced neuronal cell death after experimental brain injury in mice lacking a functional alternative pathway of complement activation. BMC Neurosci 2006; 7:55. [PMID: 16842619 PMCID: PMC1540436 DOI: 10.1186/1471-2202-7-55] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2006] [Accepted: 07/14/2006] [Indexed: 11/27/2022] Open
Abstract
Background Neuroprotective strategies for prevention of the neuropathological sequelae of traumatic brain injury (TBI) have largely failed in translation to clinical treatment. Thus, there is a substantial need for further understanding the molecular mechanisms and pathways which lead to secondary neuronal cell death in the injured brain. The intracerebral activation of the complement cascade was shown to mediate inflammation and tissue destruction after TBI. However, the exact pathways of complement activation involved in the induction of posttraumatic neurodegeneration have not yet been assessed. In the present study, we investigated the role of the alternative complement activation pathway in contributing to neuronal cell death, based on a standardized TBI model in mice with targeted deletion of the factor B gene (fB-/-), a "key" component required for activation of the alternative complement pathway. Results After experimental TBI in wild-type (fB+/+) mice, there was a massive time-dependent systemic complement activation, as determined by enhanced C5a serum levels for up to 7 days. In contrast, the extent of systemic complement activation was significantly attenuated in fB-/- mice (P < 0.05,fB-/- vs. fB+/+; t = 4 h, 24 h, and 7 days after TBI). TUNEL histochemistry experiments revealed that posttraumatic neuronal cell death was clearly reduced for up to 7 days in the injured brain hemispheres of fB-/- mice, compared to fB+/+ littermates. Furthermore, a strong upregulation of the anti-apoptotic mediator Bcl-2 and downregulation of the pro-apoptotic Fas receptor was detected in brain homogenates of head-injured fB-/- vs. fB+/+ mice by Western blot analysis. Conclusion The alternative pathway of complement activation appears to play a more crucial role in the pathophysiology of TBI than previously appreciated. This notion is based on the findings of (a) the significant attenuation of overall complement activation in head-injured fB-/- mice, as determined by a reduction of serum C5a concentrations to constitutive levels in normal mice, and (b) by a dramatic reduction of TUNEL-positive neurons in conjunction with an upregulation of Bcl-2 and downregulation of the Fas receptor in head-injured fB-/- mice, compared to fB+/+ littermates. Pharmacological targeting of the alternative complement pathway during the "time-window of opportunity" after TBI may represent a promising new strategy to be pursued in future studies.
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Affiliation(s)
- Iris Leinhase
- Department of Trauma and Reconstructive Surgery, Charité University Medical School, Campus Benjamin Franklin, 12200 Berlin, Germany
| | - V Michael Holers
- Departments of Medicine and Immunology, University of Colorado Health Sciences Center, Denver, CO 80262, USA
| | - Joshua M Thurman
- Departments of Medicine and Immunology, University of Colorado Health Sciences Center, Denver, CO 80262, USA
| | - Denise Harhausen
- Department of Trauma and Reconstructive Surgery, Charité University Medical School, Campus Benjamin Franklin, 12200 Berlin, Germany
| | - Oliver I Schmidt
- Department of Trauma and Reconstructive Surgery, Charité University Medical School, Campus Benjamin Franklin, 12200 Berlin, Germany
| | - Malte Pietzcker
- Department of Trauma and Reconstructive Surgery, Charité University Medical School, Campus Benjamin Franklin, 12200 Berlin, Germany
| | - Mohy E Taha
- Department of Trauma and Reconstructive Surgery, Charité University Medical School, Campus Benjamin Franklin, 12200 Berlin, Germany
| | - Daniel Rittirsch
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Markus Huber-Lang
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Department of Traumatology, University of Ulm Medical School, 89075 Ulm, Germany
| | - Wade R Smith
- Department of Orthopaedic Surgery, Denver Health Medical Center, University of Colorado School of Medicine, Denver, CO 80204, USA
| | - Peter A Ward
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Philip F Stahel
- Department of Trauma and Reconstructive Surgery, Charité University Medical School, Campus Benjamin Franklin, 12200 Berlin, Germany
- Department of Orthopaedic Surgery, Denver Health Medical Center, University of Colorado School of Medicine, Denver, CO 80204, USA
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