1
|
Kamble M, Saadi F, Kumar S, Saha B, Das Sarma J. Inducible nitric oxide synthase deficiency promotes murine-β-coronavirus induced demyelination. Virol J 2023; 20:51. [PMID: 36966345 PMCID: PMC10039690 DOI: 10.1186/s12985-023-02006-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 03/06/2023] [Indexed: 03/27/2023] Open
Abstract
BACKGROUND Multiple sclerosis (MS) is characterized by neuroinflammation and demyelination orchestrated by activated neuroglial cells, CNS infiltrating leukocytes, and their reciprocal interactions through inflammatory signals. An inflammatory stimulus triggers inducible nitric oxide synthase (NOS2), a pro-inflammatory marker of microglia/macrophages (MG/Mφ) to catalyze sustained nitric oxide production. NOS2 during neuroinflammation, has been associated with MS disease pathology; however, studies dissecting its role in demyelination are limited. We studied the role of NOS2 in a recombinant β-coronavirus-MHV-RSA59 induced neuroinflammation, an experimental animal model mimicking the pathological hallmarks of MS: neuroinflammatory demyelination and axonal degeneration. OBJECTIVE Understanding the role of NOS2 in murine-β-coronavirus-MHV-RSA59 demyelination. METHODS Brain and spinal cords from mock and RSA59 infected 4-5-week-old MHV-free C57BL/6 mice (WT) and NOS2-/- mice were harvested at different disease phases post infection (p.i.) (day 5/6-acute, day 9/10-acute-adaptive and day 30-chronic phase) and compared for pathological outcomes. RESULTS NOS2 was upregulated at the acute phase of RSA59-induced disease in WT mice and its deficiency resulted in severe disease and reduced survival at the acute-adaptive transition phase. Low survival in NOS2-/- mice was attributed to (i) high neuroinflammation resulting from increased accumulation of macrophages and neutrophils and (ii) Iba1 + phagocytic MG/Mφ mediated-early demyelination as observed at this phase. The phagocytic phenotype of CNS MG/Mφ was confirmed by significantly higher mRNA transcripts of phagocyte markers-CD206, TREM2, and Arg1 and double immunolabelling of Iba1 with MBP and PLP. Further, NOS2 deficiency led to exacerbated demyelination at the chronic phase as well. CONCLUSION Taken together the results imply that the immune system failed to control the disease progression in the absence of NOS2. Thus, our observations highlight a protective role of NOS2 in murine-β-coronavirus induced demyelination.
Collapse
Affiliation(s)
- Mithila Kamble
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India
| | - Fareeha Saadi
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India
| | - Saurav Kumar
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India
| | - Bhaskar Saha
- National Centre for Cell Science, Ganeshkhind, Pune, India
| | - Jayasri Das Sarma
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India.
- Department of Ophthalmology, University of Pennsylvania Scheie Eye Institute, Philadelphia, PA, 19104, USA.
| |
Collapse
|
2
|
Lima M, Aloizou AM, Siokas V, Bakirtzis C, Liampas I, Tsouris Z, Bogdanos DP, Baloyannis SJ, Dardiotis E. Coronaviruses and their relationship with multiple sclerosis: is the prevalence of multiple sclerosis going to increase after the Covid-19 pandemia? Rev Neurosci 2022; 33:703-720. [PMID: 35258237 DOI: 10.1515/revneuro-2021-0148] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 01/24/2022] [Indexed: 12/11/2022]
Abstract
The purpose of this review is to examine whether there is a possible (etiological/triggering) relationship between infection with various Coronaviruses, including Severe Acute Respiratory Syndrome-related Coronavirus-2 (SARS-CoV-2), the virus responsible for the Coronavirus disease-19 (Covid-19) pandemia, and Multiple Sclerosis (MS), and whether an increase of the prevalence of MS after the current Covid-19 pandemia should be expected, examining new and preexisting data. Although the exact pathogenesis of MS remains unknown, environmental agents seem to greatly influence the onset of the disease, with viruses being the most popular candidate. Existing data support this possible etiological relationship between viruses and MS, and experimental studies show that Coronaviruses can actually induce an MS-like demyelinating disease in animal models. Findings in MS patients could also be compatible with this coronaviral MS hypothesis. More importantly, current data from the Covid-19 pandemia show that SARS-CoV-2 can trigger autoimmunity and possibly induce autoimmune diseases, in the Central Nervous System as well, strengthening the viral hypothesis of MS. If we accept that Coronaviruses can induce MS, it is reasonable to expect an increase in the prevalence of MS after the Covid-19 pandemia. This knowledge is of great importance in order to protect the aging groups that are more vulnerable against autoimmune diseases and MS specifically, and to establish proper vaccination and health policies.
Collapse
Affiliation(s)
- Maria Lima
- Department of Neurology, University General Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41100, Larissa, Greece
| | - Athina-Maria Aloizou
- Department of Neurology, University General Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41100, Larissa, Greece
| | - Vasileios Siokas
- Department of Neurology, University General Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41100, Larissa, Greece
| | - Christos Bakirtzis
- B' Department of Neurology, Multiple Sclerosis Center, AHEPA University Hospital, Aristotle University of Thessaloniki, 54636, Thessaloniki, Greece
| | - Ioannis Liampas
- Department of Neurology, University General Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41100, Larissa, Greece
| | - Zisis Tsouris
- Department of Neurology, University General Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41100, Larissa, Greece
| | - Dimitrios P Bogdanos
- Department of Rheumatology and clinical Immunology, University General Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, 40500 Viopolis, Larissa, Greece
| | - Stavros J Baloyannis
- Research Institute for Alzheimer's disease, Aristotle University of Thessaloniki, 57200 Iraklio Lagkada, Thessaloniki, Greece.,1st Department of Neurology, AHEPA University Hospital, Aristotle University of Thessaloniki, 54636, Thessaloniki, Greece
| | - Efthimios Dardiotis
- Department of Neurology, University General Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, 41100, Larissa, Greece
| |
Collapse
|
3
|
Cui L, Ma Y, Liang Y, Zhang Y, Chen Z, Wang Z, Wu H, Li X, Xu L, Liu S, Li H. Polarization of avian macrophages upon avian flavivirus infection. Vet Microbiol 2021; 256:109044. [PMID: 33836389 DOI: 10.1016/j.vetmic.2021.109044] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 03/18/2021] [Indexed: 12/18/2022]
Abstract
Avian Tembusu virus (TMUV) is a newly emerging avian pathogenic flavivirus that spreads rapidly, has an expanding host range and undergoes cross-species transmission. Our previous study identified avian monocytes/macrophages as the key targets of TMUV infection, since the infection of host monocytes/macrophages was crucial for the replication, transmission, and pathogenesis of TMUV. The polarization of host macrophages determines the functional phenotypes of macrophages; however, the effect of TMUV infection on macrophage polarization remains unclear. Here, we analysed the expression spectra of the marker genes of macrophage polarization upon TMUV infection in the HD11 chicken macrophage cell line and primary monocytes/macrophages isolated from the peripheral blood of specific pathogen-free (SPF) chickens and ducks. We found that viral replication mainly induced M1 marker genes and triggered nitric oxide (NO) release at different levels, suggesting that TMUV infection led mainly to host macrophages polarizing into the classically activated (M1) type. The NO that was increased upon infection did not function as an antiviral agent against TMUV, since the replication of TMUV in HD11 cells was not affected by the addition of an organic NO donor. Furthermore, upon TMUV infection, polarized HD11 cells exhibited increased migration but reduced phagocytosis, as evidenced by scratch assay and neutral red uptake assay, respectively. Our present study characterized the polarization of host monocytes/macrophages upon TMUV infection, which may lay a foundation for further research on the immune escape mechanism and pathogenic mechanism of TMUV.
Collapse
Affiliation(s)
- Lu Cui
- State Key Laboratory of Veterinary Biotechnology, National Poultry Laboratory Animal Resource Center, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150069, People's Republic of China
| | - Yong Ma
- State Key Laboratory of Veterinary Biotechnology, National Poultry Laboratory Animal Resource Center, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150069, People's Republic of China
| | - Yumeng Liang
- State Key Laboratory of Veterinary Biotechnology, National Poultry Laboratory Animal Resource Center, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150069, People's Republic of China
| | - Yanhui Zhang
- State Key Laboratory of Veterinary Biotechnology, National Poultry Laboratory Animal Resource Center, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150069, People's Republic of China
| | - Zhijie Chen
- State Key Laboratory of Veterinary Biotechnology, National Poultry Laboratory Animal Resource Center, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150069, People's Republic of China
| | - Zhitao Wang
- State Key Laboratory of Veterinary Biotechnology, National Poultry Laboratory Animal Resource Center, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150069, People's Republic of China
| | - Hanguang Wu
- State Key Laboratory of Veterinary Biotechnology, National Poultry Laboratory Animal Resource Center, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150069, People's Republic of China
| | - Xuefeng Li
- State Key Laboratory of Veterinary Biotechnology, National Poultry Laboratory Animal Resource Center, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150069, People's Republic of China
| | - Li Xu
- State Key Laboratory of Veterinary Biotechnology, National Poultry Laboratory Animal Resource Center, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150069, People's Republic of China
| | - Shengwang Liu
- State Key Laboratory of Veterinary Biotechnology, National Poultry Laboratory Animal Resource Center, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150069, People's Republic of China.
| | - Hai Li
- State Key Laboratory of Veterinary Biotechnology, National Poultry Laboratory Animal Resource Center, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150069, People's Republic of China.
| |
Collapse
|
4
|
Uversky VN, Elrashdy F, Aljadawi A, Ali SM, Khan RH, Redwan EM. Severe acute respiratory syndrome coronavirus 2 infection reaches the human nervous system: How? J Neurosci Res 2021; 99:750-777. [PMID: 33217763 PMCID: PMC7753416 DOI: 10.1002/jnr.24752] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/19/2020] [Accepted: 10/21/2020] [Indexed: 02/06/2023]
Abstract
Without protective and/or therapeutic agents the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection known as coronavirus disease 2019 is quickly spreading worldwide. It has surprising transmissibility potential, since it could infect all ages, gender, and human sectors. It attacks respiratory, gastrointestinal, urinary, hepatic, and endovascular systems and can reach the peripheral nervous system (PNS) and central nervous system (CNS) through known and unknown mechanisms. The reports on the neurological manifestations and complications of the SARS-CoV-2 infection are increasing exponentially. Herein, we enumerate seven candidate routes, which the mature or immature SARS-CoV-2 components could use to reach the CNS and PNS, utilizing the within-body cross talk between organs. The majority of SARS-CoV-2-infected patients suffer from some neurological manifestations (e.g., confusion, anosmia, and ageusia). It seems that although the mature virus did not reach the CNS or PNS of the majority of patients, its unassembled components and/or the accompanying immune-mediated responses may be responsible for the observed neurological symptoms. The viral particles and/or its components have been specifically documented in endothelial cells of lung, kidney, skin, and CNS. This means that the blood-endothelial barrier may be considered as the main route for SARS-CoV-2 entry into the nervous system, with the barrier disruption being more logical than barrier permeability, as evidenced by postmortem analyses.
Collapse
Affiliation(s)
- Vladimir N. Uversky
- Biological Science DepartmentFaculty of ScienceKing Abdulaziz UniversityJeddahSaudi Arabia
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of MedicineUniversity of South FloridaTampaFLUSA
- Institute for Biological Instrumentation of the Russian Academy of SciencesFederal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”PushchinoRussia
| | - Fatma Elrashdy
- Department of Endemic Medicine and HepatogastroenterologyKasr Alainy School of MedicineCairo UniversityCairoEgypt
| | - Abdullah Aljadawi
- Biological Science DepartmentFaculty of ScienceKing Abdulaziz UniversityJeddahSaudi Arabia
| | - Syed Moasfar Ali
- Interdisciplinary Biotechnology UnitAligarh Muslim UniversityAligarhIndia
| | - Rizwan Hasan Khan
- Interdisciplinary Biotechnology UnitAligarh Muslim UniversityAligarhIndia
| | - Elrashdy M. Redwan
- Biological Science DepartmentFaculty of ScienceKing Abdulaziz UniversityJeddahSaudi Arabia
| |
Collapse
|
5
|
SARS-CoV-2 Infection Leads to Neurological Dysfunction. J Neuroimmune Pharmacol 2020; 15:167-173. [PMID: 32447746 PMCID: PMC7244399 DOI: 10.1007/s11481-020-09924-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 05/06/2020] [Indexed: 02/06/2023]
Abstract
A number of neurological disease complications have been seen following infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While most person with COVID-19 respiratory disease demonstrate headache, nausea and vomiting, up to 40% present also experience dizziness, confusion, cerebrovascular disease, muscle pain, ataxia and seizures. Loss of taste and smell, defects in visual acuity and pain occur in parallel. Such central nervous system (CNS) signs and symptoms linked to laboratory-confirmed SARS-CoV-2 infection is often life threatening. Health care providers currently evaluating patients with neurologic symptoms need consider COVID-19 in any differential diagnosis. These considerations will facilitate prompt testing, isolation and prevention of viral transmission speeding best clinical outcomes. Graphical Abstract ![]()
Collapse
|
6
|
Yamamoto K, Takahashi K, Ato M, Iwanaga S, Ohta N. Antimalarial activity of vitamin D3 (VD3) does not result from VD3-induced antimicrobial agents including nitric oxide or cathelicidin. Exp Parasitol 2019; 201:67-77. [PMID: 30904694 DOI: 10.1016/j.exppara.2019.03.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 03/01/2019] [Accepted: 03/17/2019] [Indexed: 01/29/2023]
Abstract
Recent evidence suggests that 1α,25-dihydroxyvitamin D3 (VD3), the active form of vitamin D, inhibits microbial proliferation. Previously, we used in vivo murine models to investigate the antimalarial activity of VD3 and confirmed potent antimalarial activity in the acute phase. This study aimed to clarify the mechanisms underlying the antimalarial activity of VD3 in vivo, particularly extensive inhibition of parasitemia in the acute phase, focusing on nitric oxide (NO), a potent antimalarial molecule. VD3 is a good NO inducer. When most Plasmodium chabaudi AS (PcAS)-infected mice treated with VD3 survived, NO was present in blood samples obtained from VD3-treated mice at a significantly higher rate at 2 and/or 3 days post-infection than that in vehicle-treated control mice. To verify the involvement of NO in the antimalarial activity of VD3, we used aminoguanidine (AG), an inducible NO synthase (iNOS) inhibitor, to abrogate the antimalarial activity of VD3. However, despite AG-induced reductions in NO levels, parasitemia remained inhibited during the acute phase, even in the presence of AG, and the antiplasmodial faculty of VD3 was not ablated. VD3-mediated antimalarial activity irrelevant of NO compelled us to consider another candidate. In a pilot experiment, we used cathelicidin (CAMP), an antimicrobial peptide, since it is known that VD3 induces CAMP synthesis. Serum CAMP levels increased on days 4 or 5 post-infection with or without VD3 administration, but experiments using exogenous CAMP did not display curative effects in PcAS-infected mice. The present study using VD3 to target the malarial parasite thus suggests a potential novel approach to treat malarial infections.
Collapse
Affiliation(s)
- Kiichi Yamamoto
- Section of Environmental Parasitology, Tokyo Medical and Dental University, Japan.
| | - Kentaro Takahashi
- Department of Bio-informational Pharmacology, Tokyo Medical and Dental University, Japan
| | - Manabu Ato
- Department of Mycobacteriology, National Institute of Infectious Diseases, Japan
| | - Shiroh Iwanaga
- Section of Environmental Parasitology, Tokyo Medical and Dental University, Japan
| | - Nobuo Ohta
- Section of Environmental Parasitology, Tokyo Medical and Dental University, Japan; Department of Clinical Nutrition, Faculty of Health Science, Suzuka University of Medical Science, Japan
| |
Collapse
|
7
|
Savarin C, Bergmann CC. Fine Tuning the Cytokine Storm by IFN and IL-10 Following Neurotropic Coronavirus Encephalomyelitis. Front Immunol 2018; 9:3022. [PMID: 30619363 PMCID: PMC6306494 DOI: 10.3389/fimmu.2018.03022] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 12/06/2018] [Indexed: 12/13/2022] Open
Abstract
The central nervous system (CNS) is vulnerable to several viral infections including herpes viruses, arboviruses and HIV to name a few. While a rapid and effective immune response is essential to limit viral spread and mortality, this anti-viral response needs to be tightly regulated in order to limit immune mediated tissue damage. This balance between effective virus control with limited pathology is especially important due to the highly specialized functions and limited regenerative capacity of neurons, which can be targets of direct virus cytolysis or bystander damage. CNS infection with the neurotropic strain of mouse hepatitis virus (MHV) induces an acute encephalomyelitis associated with focal areas of demyelination, which is sustained during viral persistence. Both innate and adaptive immune cells work in coordination to control virus replication. While type I interferons are essential to limit virus spread associated with early mortality, perforin, and interferon-γ promote further virus clearance in astrocytes/microglia and oligodendrocytes, respectively. Effective control of virus replication is nonetheless associated with tissue damage, characterized by demyelinating lesions. Interestingly, the anti-inflammatory cytokine IL-10 limits expansion of tissue lesions during chronic infection without affecting viral persistence. Thus, effective coordination of pro- and anti-inflammatory cytokines is essential during MHV induced encephalomyelitis in order to protect the host against viral infection at a limited cost.
Collapse
Affiliation(s)
- Carine Savarin
- Department of Neuroscience, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH, United States
| | - Cornelia C Bergmann
- Department of Neuroscience, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH, United States
| |
Collapse
|
8
|
Abstract
Neurotropic strains of the mouse hepatitis virus (MHV) cause a range of diseases in infected mice ranging from mild encephalitis with clearance of the virus followed by demyelination to rapidly fatal encephalitis. This chapter discusses the structure, life cycle, transmission, and pathology of neurotropic coronaviruses, as well as the immune response to coronavirus infection. Mice infected with neurotropic strains of MHV have provided useful systems in which to study processes of virus- and immune-mediated demyelination and virus clearance and/or persistence in the CNS, and the mechanisms of virus evasion of the immune system.
Collapse
|
9
|
Phares TW, Stohlman SA, Hinton DR, Bergmann CC. Enhanced CD8 T-cell anti-viral function and clinical disease in B7-H1-deficient mice requires CD4 T cells during encephalomyelitis. J Neuroinflammation 2012; 9:269. [PMID: 23237504 PMCID: PMC3545890 DOI: 10.1186/1742-2094-9-269] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 12/03/2012] [Indexed: 12/11/2022] Open
Abstract
Background Anti-viral CD8 T-cell activity is enhanced and prolonged by CD4 T-cell-mediated help, but negatively regulated by inhibitory B7-H1 interactions. During viral encephalomyelitis, the absence of CD4 T cells decreases CD8 T cell activity and impedes viral control in the central nervous system (CNS). By contrast, the absence of B7-H1 enhances CD8 T-cell function and accelerates viral control, but increases morbidity. However, the relative contribution of CD4 T cells to CD8 function in the CNS, in the absence of B7-H1, remains unclear. Methods Wild-type (WT) and B7-H1−/− mice were infected with a gliatropic coronavirus and CD4 T cells depleted to specifically block T helper function in the CNS. Flow cytometry and gene expression analysis of purified T-cell populations from lymph nodes and the CNS was used to directly monitor ex vivo T-cell effector function. The biological affects of altered T-cell responses were evaluated by analysis of viral control and spinal-cord pathology. Results Increased anti-viral activity by CD8 T cells in the CNS of B7-H1−/− mice was lost upon depletion of CD4 T cells; however, despite concomitant loss of viral control, the clinical disease was less severe. CD4 depletion in B7-H1−/− mice also decreased inducible nitric oxide synthase expression by microglia and macrophages, consistent with decreased microglia/macrophage activation and reduced interferon (IFN)-γ. Enhanced production of IFN-γ, interleukin (IL)-10 and IL-21 mRNA was seen in CD4 T cells from infected B7-H1−/− compared with WT mice, suggesting that over-activated CD4 T cells primarily contribute to the increased pathology. Conclusions The local requirement of CD4 T-cell help for CD8 T-cell function is not overcome if B7-H1 inhibitory signals are lost. Moreover, the increased effector activity by CD8 T cells in the CNS of B7-H1−/− mice is attributable not only to the absence of B7-H1 upregulation on major histocompatibility complex class I-presenting resident target cells, but also to enhanced local CD4 T-cell function. B7-H1-mediated restraint of CD4 T-cell activity is thus crucial to dampen both CD8 T-cell function and microglia/macrophage activation, thereby providing protection from T-cell-mediated bystander damage.
Collapse
Affiliation(s)
- Timothy W Phares
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | | | | | | |
Collapse
|
10
|
Boga JA, Coto-Montes A, Rosales-Corral SA, Tan DX, Reiter RJ. Beneficial actions of melatonin in the management of viral infections: a new use for this "molecular handyman"? Rev Med Virol 2012; 22:323-38. [PMID: 22511571 PMCID: PMC7169144 DOI: 10.1002/rmv.1714] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 02/08/2012] [Accepted: 02/09/2012] [Indexed: 12/24/2022]
Abstract
Melatonin (N‐acetyl‐5‐methoxytryptamine) is a multifunctional signaling molecule that has a variety of important functions. Numerous clinical trials have examined the therapeutic usefulness of melatonin in different fields of medicine. Clinical trials have shown that melatonin is efficient in preventing cell damage under acute (sepsis, asphyxia in newborns) and chronic states (metabolic and neurodegenerative diseases, cancer, inflammation, aging). The beneficial effects of melatonin can be explained by its properties as a potent antioxidant and antioxidant enzyme inducer, a regulator of apoptosis and a stimulator of immune functions. These effects support the use of melatonin in viral infections, which are often associated with inflammatory injury and increases in oxidative stress. In fact, melatonin has been used recently to treat several viral infections, which are summarized in this review. The role of melatonin in infections is also discussed herein. Copyright © 2012 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Jose Antonio Boga
- Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, Texas, USA
| | | | | | | | | |
Collapse
|
11
|
Marro BS, Hosking MP, Lane TE. CXCR2 signaling and host defense following coronavirus-induced encephalomyelitis. Future Virol 2012; 7:349-359. [PMID: 22582084 DOI: 10.2217/fvl.12.23] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Inoculation of the neurotropic JHM strain of mouse hepatitis virus (JHMV) into the central nervous system (CNS) of susceptible strains of mice results in wide-spread replication within glial cells accompanied by infiltration of virus-specific T lymphocytes that control virus through cytokine secretion and cytolytic activity. Virus persists within white matter tracts of surviving mice resulting in demyelination that is amplified by inflammatory T cells and macrophages. In response to infection, numerous cytokines/chemokines are secreted by resident cells of the CNS and inflammatory leukocytes that participate in both host defense and disease. Among these are the ELR-positive chemokines that are able to signal through CXC chemokine receptors including CXCR2. Early following JHMV infection, ELR-positive chemokines contribute to host defense by attracting CXCR2-expressing cells including polymorphonuclear cells to the CNS that aid in host defense through increasing the permeability the blood-brain-barrier (BBB). During chronic disease, CXCR2 signaling on oligodendroglia protects these cells from apoptosis and restricts the severity of demyelination. This review covers aspects related to host defense and disease in response to JHMV infection and highlights the different roles of CXCR2 signaling in these processes.
Collapse
Affiliation(s)
- Brett S Marro
- Department of Molecular Biology & Biochemistry, University of California, Irvine 92697-3900
| | | | | |
Collapse
|
12
|
Phares TW, Stohlman SA, Hinton DR, Atkinson R, Bergmann CC. Enhanced antiviral T cell function in the absence of B7-H1 is insufficient to prevent persistence but exacerbates axonal bystander damage during viral encephalomyelitis. THE JOURNAL OF IMMUNOLOGY 2010; 185:5607-18. [PMID: 20876353 DOI: 10.4049/jimmunol.1001984] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The T cell inhibitory ligand B7-H1 hinders T cell-mediated virus control, but also ameliorates clinical disease during autoimmune and virus-induced CNS disease. In mice infected with gliatropic demyelinating coronavirus, B7-H1 expression on oligodendroglia delays virus control, but also dampens clinical disease. To define the mechanisms by which B7-H1 alters pathogenic outcome, virus-infected B7-H1-deficient (B7-H1(-/-)) mice were analyzed for altered peripheral and CNS immune responses. B7-H1 deficiency did not affect peripheral T or B cell activation or alter the magnitude or composition of CNS-infiltrating cells. However, higher levels of IFN-γ mRNA in CNS-infiltrating virus-specific CD8 T cells as well as CD4 T cells contributed to elevated IFN-γ protein in the B7-H1(-/-) CNS. Increased effector function at the single-cell level was also evident by elevated granzyme B expression specifically in virus-specific CNS CD8 T cells. Although enhanced T cell activity accelerated virus control, 50% of mice succumbed to infection. Despite enhanced clinical recovery, surviving B7-H1(-/-) mice still harbored persisting viral mRNA, albeit at reduced levels compared with wild-type mice. B7-H1(-/-) mice exhibited extensive loss of axonal integrity, although demyelination, a hallmark of virus-induced tissue damage, was not increased. The results suggest that B7-H1 hinders viral control in B7-H1 expressing glia cells, but does not mediate resistance to CD8 T cell-mediated cytolysis. These data are the first, to our knowledge, to demonstrate that B7-H1-mediated protection from viral-induced immune pathology associated with encephalomyelitis resides in limiting T cell-mediated axonal bystander damage rather than direct elimination of infected myelinating cells.
Collapse
Affiliation(s)
- Timothy W Phares
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | | | | | | | | |
Collapse
|
13
|
Abstract
Advances in free radical research show that reactive oxygen and nitrogen oxide species, for example superoxide, nitric oxide (NO) and peroxynitrite, play an important role in the pathogenesis of different viral infections, including dengue virus. The pathogenic mechanism of dengue haemorrhagic fever (DHF) is complicated and is not clearly understood. The hallmarks of the dengue disease, the antibody‐dependent enhancement, the shift from T‐helper type 1 (Th1) to Th2 cytokine response and the cytokine tsunami resulting in vascular leakage can now be explained much better with the knowledge gained about NO and peroxynitrite. This paper makes an effort to present a synthesis of the current opinions to explain the pathogenesis of DHF/shock syndrome with NO on centre stage.
Collapse
|
14
|
Burrer R, Buchmeier MJ, Wolfe T, Ting JPC, Feuer R, Iglesias A, von Herrath MG. Exacerbated pathology of viral encephalitis in mice with central nervous system-specific autoantibodies. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 170:557-66. [PMID: 17255324 PMCID: PMC1851853 DOI: 10.2353/ajpath.2007.060893] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Accepted: 10/31/2006] [Indexed: 11/30/2022]
Abstract
We examine here the outcome of viral encephalomyelitis [mouse hepatitis virus (MHV) A59, Theiler's encephalomyelitis virus, and Coxsackievirus B3] in mice with autoantibodies to a central nervous system (CNS)-specific antigen, myelin oligodendrocyte glycoprotein, that usually develop no clinical disease. Morbidity and mortality of the acute viral CNS disease was augmented by the presence of the autoantibodies in all three viral infections. Transfer of serum containing the autoantibodies at the time of infection with MHV was sufficient to reproduce the exacerbated disease. The presence of the autoantibodies was found to result in increased infiltration of mononuclear cells into the brain. Early demyelination was severely augmented in brains and spinal cords of MHV-infected mice with CNS-specific autoantibodies. The antibody-mediated exacerbation was shown to be independent of the complement system but to require expression of Fc receptors, because it was observed in C'-3-deficient but not in Fc receptor-deficient mice. Our study illustrates the possibility that infections can lead to much more profound immunopathology in the presence of an otherwise latent autoimmune condition.
Collapse
Affiliation(s)
- Renaud Burrer
- Molecular and Integrative Neurosciences Department, The Scrips Research Institute, La Jolla, CA 92037, USA
| | | | | | | | | | | | | |
Collapse
|
15
|
Perlman S, Holmes KV. Coronavirus immunity: from T cells to B cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 581:341-9. [PMID: 17037557 PMCID: PMC7124054 DOI: 10.1007/978-0-387-33012-9_61] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Affiliation(s)
- Stanley Perlman
- Department of Pediatrics, University of Iowa, 52242 Iowa City, IA USA
| | - Kathryn V. Holmes
- Department of Microbiology, University of Colorado Health Sciences Center at Fitzsimons, 80045-8333 Aurora, CO USA
| |
Collapse
|
16
|
Bergmann CC, Lane TE, Stohlman SA. Coronavirus infection of the central nervous system: host-virus stand-off. Nat Rev Microbiol 2006; 4:121-32. [PMID: 16415928 PMCID: PMC7096820 DOI: 10.1038/nrmicro1343] [Citation(s) in RCA: 298] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Several viruses infect the mammalian central nervous system (CNS), some with devastating consequences, others resulting in chronic or persistent infections associated with little or no overt pathology. Coronavirus infection of the murine CNS illustrates the contributions of both the innate immune response and specific host effector mechanisms that control virus replication in distinct CNS cell types. Despite T-cell-mediated control of acute virus infection, host regulatory mechanisms, probably designed to protect CNS integrity, contribute to the failure to eliminate virus. Distinct from cytolytic effector mechanisms expressed during acute infection, non-lytic humoral immunity prevails in suppressing infectious virus during persistence.
Collapse
Affiliation(s)
- Cornelia C. Bergmann
- Cleveland Clinic Foundation, Neurosciences, 9500 Euclid Avenue NC30, Cleveland, 44195 Ohio USA
| | - Thomas E. Lane
- University of California, Irvine, Molecular Biology & Biochemistry, 3205 McGaugh Hall, Irvine, 92697 California USA
| | - Stephen A. Stohlman
- Cleveland Clinic Foundation, Neurosciences, 9500 Euclid Avenue NC30, Cleveland, 44195 Ohio USA
| |
Collapse
|
17
|
The Role of T Cells in Corona-Virus-Induced Demyelination. EXPERIMENTAL MODELS OF MULTIPLE SCLEROSIS 2005. [PMCID: PMC7121318 DOI: 10.1007/0-387-25518-4_40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Mice infected with neurotropic strains of coronavirus develop acute encephalomyelitis and eliminate infectious virus. However, control of acute infection is incomplete resulting in persistence of viral RNA in the central nervous system (CNS) associated with ongoing primary demyelination. A high prevalence of virus specific CD8 and CD4 T cells within the CNS correlates with ex vivo cytolytic activity and IFN-γ secretion, which are both required for virus reduction during the acute infection. Although most infected cell types are susceptible to perforin mediated clearance, IFN-γ is required for controlling infection of oligodendrocytes. Furthermore, by enhancing class I expression and inducing class II expression within resident CNS cells IFN-γ optimizes T cell receptor dependent functions. In addition to its direct anti viral activity, these multifactorial effects make IFN-γ more essential than perforin for viral control. CD4 T cells enhance CD8 T cell expansion, survival and effectiveness. Although both CD8 and CD4 T cells are retained within the CNS during persistence, they cannot control viral recrudescence in the absence of humoral immunity. Demyelination can be mediated by either CD8 or CD4 T cells; however, although a variety of effector molecules have been excluded, a dominant common denominator remains elusive. Thus concerted efforts to control infection coincide with a variety of potential mechanisms causing chronic demyelinating disease.
Collapse
|
18
|
Li Y, Lavi E. The Role of Astrocytes, Microglia, and Endothelial Cells in Coronavirus-Induced Demyelination. EXPERIMENTAL MODELS OF MULTIPLE SCLEROSIS 2005. [PMCID: PMC7121167 DOI: 10.1007/0-387-25518-4_38] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
19
|
Li Y, Fu L, Gonzales DM, Lavi E. Coronavirus neurovirulence correlates with the ability of the virus to induce proinflammatory cytokine signals from astrocytes and microglia. J Virol 2004; 78:3398-406. [PMID: 15016862 PMCID: PMC371061 DOI: 10.1128/jvi.78.7.3398-3406.2004] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The molecular and cellular basis of coronavirus neurovirulence is poorly understood. Since neurovirulence may be determined at the early stages of infection of the central nervous system (CNS), we hypothesize that it may depend on the ability of the virus to induce proinflammatory signals from brain cells for the recruitment of blood-derived inflammatory cells. To test this hypothesis, we studied the interaction between coronaviruses (mouse hepatitis virus) of different neurovirulences with primary cell cultures of brain immune cells (astrocytes and microglia) and mouse tissues. We found that the level of neurovirulence of the virus correlates with its differential ability to induce proinflammatory cytokines (interleukin 12 [IL-12] p40, tumor necrosis factor alpha, IL-6, IL-15, and IL-1beta) in astrocytes and microglia and in mouse brains and spinal cords. These findings suggest that coronavirus neurovirulence may depend on a novel discriminatory ability of astrocytes and microglia to induce a proinflammatory response in the CNS.
Collapse
Affiliation(s)
- Yun Li
- Division of Neuropathology, Department of Pathology and Laboratory Medicine, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | | | | | | |
Collapse
|
20
|
Navas-Martín S, Weiss SR. Coronavirus replication and pathogenesis: Implications for the recent outbreak of severe acute respiratory syndrome (SARS), and the challenge for vaccine development. J Neurovirol 2004; 10:75-85. [PMID: 15204926 PMCID: PMC7095027 DOI: 10.1080/13550280490280292] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2003] [Accepted: 12/10/2003] [Indexed: 12/28/2022]
Abstract
A novel coronavirus has been recently identified as the causative agent of the severe acute respiratory syndrome (SARS) outbreak that has accounted for more than 8000 infected people worldwide. This review will discuss current knowledge on coronavirus replication, pathogenesis, evolution, and vaccine strategies, as well as the most recent findings on SARS coronavirus.
Collapse
Affiliation(s)
- Sonia Navas-Martín
- Department of Microbiology, University of Pennsylvania, School of Medicine, 36th Street and Hamilton Walk, 19104-6076 Philadelphia, PA USA
| | - Susan R. Weiss
- Department of Microbiology, University of Pennsylvania, School of Medicine, 36th Street and Hamilton Walk, 19104-6076 Philadelphia, PA USA
| |
Collapse
|
21
|
Oleszak EL, Chang JR, Friedman H, Katsetos CD, Platsoucas CD. Theiler's virus infection: a model for multiple sclerosis. Clin Microbiol Rev 2004; 17:174-207. [PMID: 14726460 PMCID: PMC321460 DOI: 10.1128/cmr.17.1.174-207.2004] [Citation(s) in RCA: 206] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Both genetic background and environmental factors, very probably viruses, appear to play a role in the etiology of multiple sclerosis (MS). Lessons from viral experimental models suggest that many different viruses may trigger inflammatory demyelinating diseases resembling MS. Theiler's virus, a picornavirus, induces in susceptible strains of mice early acute disease resembling encephalomyelitis followed by late chronic demyelinating disease, which is one of the best, if not the best, animal model for MS. During early acute disease the virus replicates in gray matter of the central nervous system but is eliminated to very low titers 2 weeks postinfection. Late chronic demyelinating disease becomes clinically apparent approximately 2 weeks later and is characterized by extensive demyelinating lesions and mononuclear cell infiltrates, progressive spinal cord atrophy, and axonal loss. Myelin damage is immunologically mediated, but it is not clear whether it is due to molecular mimicry or epitope spreading. Cytokines, nitric oxide/reactive nitrogen species, and costimulatory molecules are involved in the pathogenesis of both diseases. Close similarities between Theiler's virus-induced demyelinating disease in mice and MS in humans, include the following: major histocompatibility complex-dependent susceptibility; substantial similarities in neuropathology, including axonal damage and remyelination; and paucity of T-cell apoptosis in demyelinating disease. Both diseases are immunologically mediated. These common features emphasize the close similarities of Theiler's virus-induced demyelinating disease in mice and MS in humans.
Collapse
Affiliation(s)
- Emilia L Oleszak
- Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19106, USA.
| | | | | | | | | |
Collapse
|
22
|
Pewe L, Haring J, Perlman S. CD4 T-cell-mediated demyelination is increased in the absence of gamma interferon in mice infected with mouse hepatitis virus. J Virol 2002; 76:7329-33. [PMID: 12072531 PMCID: PMC136326 DOI: 10.1128/jvi.76.14.7329-7333.2002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Mice infected with the murine coronavirus, mouse hepatitis virus, strain JHM (MHV) develop an immune-mediated demyelinating encephalomyelitis. Adoptive transfer of MHV-immune splenocytes depleted of either CD4 or CD8 T cells to infected mice deficient in recombination activation gene 1 resulted in demyelination. We showed previously that the process of CD8 T-cell-mediated demyelination was strongly dependent on the expression of gamma interferon (IFN-gamma) by donor cells. In this report, we show, in contrast, that demyelination and lymphocyte infiltration were increased in recipients of IFN-gamma(-/-) CD4 T cells when compared to levels in mice receiving C57BL/6 CD4 T cells.
Collapse
Affiliation(s)
- Lecia Pewe
- Department of Pediatrics, University of Iowa, Iowa City, Iowa 52242, USA
| | | | | |
Collapse
|
23
|
Chen BP, Lane TE. Lack of nitric oxide synthase type 2 (NOS2) results in reduced neuronal apoptosis and mortality following mouse hepatitis virus infection of the central nervous system. J Neurovirol 2002; 8:58-63. [PMID: 11847593 PMCID: PMC7094997 DOI: 10.1080/135502802317247820] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The role of nitric oxide synthase type-2 (NOS2)-derived nitric oxide (NO) in the pathogenesis of mouse hepatitis virus (MHV)-induced central nervous system disease was examined. Infection of NOS2 knockout ((-/-)) and NOS2(+/+) mice with MHV resulted in similar kinetics of viral clearance from the brain and comparable levels of demyelination. MHV-infected NOS2(-/-) mice displayed a marked decrease in mortality as compared to infected NOS2(+/+) mice that correlated with a significant decrease (P < or = 0.001) in the number of apoptotic cells (determined by TUNEL staining) present in the brain. Confocal microscopy revealed that the majority of cells (>70%) undergoing apoptosis were neurons. These studies indicate that NOS2-generated NO contributes to apoptosis of neurons but not demyelination following MHV infection.
Collapse
Affiliation(s)
- Benjamin P. Chen
- Dept. of Molecular Biology and Biochemistry, University of California-Irvine, 3205 Biological Sciences II, 92697 Irvine, CA USA
| | - Thomas E. Lane
- Dept. of Molecular Biology and Biochemistry, University of California-Irvine, 3205 Biological Sciences II, 92697 Irvine, CA USA
- Reeve-Irvine Research Center, University of California-Irvine, Irvine, California USA
| |
Collapse
|
24
|
Ubol S, Hiriote W, Anuntagool N, Utaisincharoen P. A radical form of nitric oxide suppresses RNA synthesis of rabies virus. Virus Res 2001; 81:125-32. [PMID: 11682131 DOI: 10.1016/s0168-1702(01)00378-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Hydrophobia is an incurable disease of the central nervous system. Therefore, every mode of the immune response is important to inhibit and clear infection. Innate immunity such as nitric oxide is significantly upregulated during rabies virus infection in vivo. In this report, the possible role of nitric oxide in inhibition of rabies virus replication was studied. Rabies virus infected neuroblastoma cells were treated with nitric oxide generated from SNP or SNP in the presence of ascorbate. SNP-ascorbate generates mainly NO* in culture medium while NO(+) is the major product of SNP alone. Treatment with SNP-ascorbate resulted in delay and suppression of infectious viral particle production. In contrast, treatment with SNP alone did not interfere with multiplication of this virus. The mechanism of inhibition by NO was at the level of gene expression, which was demonstrated by reduction in the level of N, G and L gene expression. The effect of SNP-ascorbate generated NO on rabies virus protein synthesis was also investigated. Synthesis of N protein in the presence of NO was suppressed which correlated to down regulation of N gene expression. We hypothesize that one of the roles of NO in the central nervous system during rabies virus infection is to limit viral dissemination by down-regulating rabies virus production through transcription inhibition.
Collapse
Affiliation(s)
- S Ubol
- Department of Microbiology, Faculty of Science, Mahidol University, Rama VI Rd., 10400, Bangkok, Thailand.
| | | | | | | |
Collapse
|
25
|
Abstract
During the past two decades, nitric oxide (NO) has been recognized as one of the most versatile players in the immune system. It is involved in the pathogenesis and control of infectious diseases, tumors, autoimmune processes and chronic degenerative diseases. Because of its variety of reaction partners (DNA, proteins, low-molecular weight thiols, prosthetic groups, reactive oxygen intermediates), its widespread production (by three different NO synthases (NOS) and the fact that its activity is strongly influenced by its concentration, NO continues to surprise and perplex immunologists. Today, there is no simple, uniform picture of the function of NO in the immune system. Protective and toxic effects of NO are frequently seen in parallel. Its striking inter- and intracellular signaling capacity makes it extremely difficult to predict the effect of NOS inhibitors and NO donors, which still hampers therapeutic applications.
Collapse
Affiliation(s)
- C Bogdan
- Institute of Clinical Microbiology, Immunology and Hygiene, Friedrich-Alexander-University of Erlangen-Nuremberg, Wasserturmstrasse 3-5, D-91054 Erlangen, Germany.
| |
Collapse
|
26
|
Abstract
Oxygen radicals and nitric oxide (NO) are generated in excess in a diverse array of microbial infections. Emerging concepts in free radical biology are now shedding light on the pathogenesis of various diseases. Free-radical induced pathogenicity in virus infections is of great importance, because evidence suggests that NO and oxygen radicals such as superoxide are key molecules in the pathogenesis of various infectious diseases. Although oxygen radicals and NO have an antimicrobial effect on bacteria and protozoa, they have opposing effects in virus infections such as influenza virus pneumonia and several other neurotropic virus infections. A high output of NO from inducible NO synthase, occurring in a variety of virus infections, produces highly reactive nitrogen oxide species, such as peroxynitrite, via interaction with oxygen radicals and reactive oxygen intermediates. The production of these various reactive species confers the diverse biological functions of NO. The reactive nitrogen species cause oxidative tissue injury and mutagenesis through oxidation and nitration of various biomolecules. The unique biological properties of free radicals are further illustrated by recent evidence showing accelerated viral mutation by NO-induced oxidative stress. NO appears to affect a host's immune response, with immunopathological consequences. For example, NO is reported to suppress type 1 helper T cell-dependent immune responses during infections, leading to type 2 helper T cell-biased immunological host responses. NO-induced immunosuppression may thus contribute to the pathogenesis of virus infections and help expansion of quasispecies population of viral pathogens. This review describes the pathophysiological roles of free radicals in the pathogenesis of viral disease and in viral mutation as related to both nonspecific inflammatory responses and immunological host reactions modulated by NO.
Collapse
Affiliation(s)
- T Akaike
- Department of Microbiology, Kumamoto University School of Medicine, Kumamoto 860-0811, Japan.
| |
Collapse
|
27
|
Abstract
Nitric oxide (NO) has complex and diverse functions in physiological and pathophysiological phenomena. The mechanisms of many events induced by NO are now well defined, so that a fundamental understanding of NO biology is almost established. Accumulated evidence suggests that NO and oxygen radicals such as superoxide are key molecules in the pathogenesis of various infectious diseases. NO biosynthesis, particularly through expression of an inducible NO synthase (iNOS), occurs in a variety of microbial infections. Although antimicrobial activity of NO is appreciated for bacteria and protozoa, NO has opposing effects in virus infections such as influenza virus pneumonia and certain other neurotropic virus infections. iNOS produces an excessive amount of NO for long periods, which allows generation of a highly reactive nitrogen oxide species, peroxynitrite, via a radical coupling reaction of NO with superoxide. Thus, peroxynitrite causes oxidative tissue injury through potent oxidation and nitration reactions of various biomolecules. NO also appears to affect a host's immune response, with immunopathological consequences. For example, overproduction of NO in virus infections in mice is reported to suppress type 1 helper T-cell-dependent immune responses, leading to type 2 helper T-cell-biased immunological host responses. Thus, NO may be a host response modulator rather than a simple antiviral agent. The unique biological properties of NO are further illustrated by our recent data suggesting that viral mutation and evolution may be accelerated by NO-induced oxidative stress. Here, we discuss these multiple roles of NO in pathogenesis of virus infections as related to both non-specific inflammatory responses and immunological host reactions modulated by NO during infections in vivo.
Collapse
Affiliation(s)
- T Akaike
- Department of Microbiology, Kumamoto University School of Medicine, Kumamoto, Japan
| | | |
Collapse
|
28
|
Wu GF, Dandekar AA, Pewe L, Perlman S. CD4 and CD8 T cells have redundant but not identical roles in virus-induced demyelination. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:2278-86. [PMID: 10925317 DOI: 10.4049/jimmunol.165.4.2278] [Citation(s) in RCA: 161] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A chronic demyelinating disease results from murine infection with the neurotropic strain JHM of mouse hepatitis virus (MHV-JHM). Demyelination is largely immune mediated. In this study, the individual roles of CD4 and CD8 T cells in MHV-induced demyelination were investigated using recombination-activating gene 1-/- (RAG1-/-) mice infected with an attenuated strain of MHV-JHM. These animals develop demyelination only after adoptive transfer of splenocytes from mice previously immunized to MHV. In this study, we show that, following adoptive transfer, virus-specific CD4 and CD8 T cells rapidly infiltrate the CNS of MHV-JHM-infected RAG1-/- mice. Adoptive transfer of CD4 T cell-enriched donors resulted in more severe clinical disease accompanied by less demyelination than was detected in the recipients of undepleted cells. Macrophage infiltration into the gray matter of CD4 T cell-enriched recipients was greater than that observed in mice receiving undepleted splenocytes. In contrast, CD8 T cell-enriched recipients developed delayed disease with extensive demyelination of the spinal cord. MHV-JHM-infected RAG1-/- mice receiving donors depleted of both CD4 and CD8 T cells did not develop demyelination. These results demonstrate that the development of demyelination following MHV infection may be initiated by either CD4 or CD8 T cells. Furthermore, they show that CD4 T cells contribute more prominently than CD8 T cells to the severity of clinical disease, and that this correlates with increased macrophage infiltration into the gray matter.
Collapse
Affiliation(s)
- G F Wu
- Program in Neuroscience, Departments of Pediatrics and Microbiology, and University of Iowa College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | | | | | | |
Collapse
|