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Ko CN, Zang S, Zhou Y, Zhong Z, Yang C. Nanocarriers for effective delivery: modulation of innate immunity for the management of infections and the associated complications. J Nanobiotechnology 2022; 20:380. [PMID: 35986268 PMCID: PMC9388998 DOI: 10.1186/s12951-022-01582-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 08/01/2022] [Indexed: 12/24/2022] Open
Abstract
Innate immunity is the first line of defense against invading pathogens. Innate immune cells can recognize invading pathogens through recognizing pathogen-associated molecular patterns (PAMPs) via pattern recognition receptors (PRRs). The recognition of PAMPs by PRRs triggers immune defense mechanisms and the secretion of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6. However, sustained and overwhelming activation of immune system may disrupt immune homeostasis and contribute to inflammatory disorders. Immunomodulators targeting PRRs may be beneficial to treat infectious diseases and their associated complications. However, therapeutic performances of immunomodulators can be negatively affected by (1) high immune-mediated toxicity, (2) poor solubility and (3) bioactivity loss after long circulation. Recently, nanocarriers have emerged as a very promising tool to overcome these obstacles owning to their unique properties such as sustained circulation, desired bio-distribution, and preferred pharmacokinetic and pharmacodynamic profiles. In this review, we aim to provide an up-to-date overview on the strategies and applications of nanocarrier-assisted innate immune modulation for the management of infections and their associated complications. We first summarize examples of important innate immune modulators. The types of nanomaterials available for drug delivery, as well as their applications for the delivery of immunomodulatory drugs and vaccine adjuvants are also discussed.
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Singh H, Koury J, Kaul M. Innate Immune Sensing of Viruses and Its Consequences for the Central Nervous System. Viruses 2021; 13:170. [PMID: 33498715 PMCID: PMC7912342 DOI: 10.3390/v13020170] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 12/13/2022] Open
Abstract
Viral infections remain a global public health concern and cause a severe societal and economic burden. At the organismal level, the innate immune system is essential for the detection of viruses and constitutes the first line of defense. Viral components are sensed by host pattern recognition receptors (PRRs). PRRs can be further classified based on their localization into Toll-like receptors (TLRs), C-type lectin receptors (CLR), retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs), NOD-like receptors (NLRs) and cytosolic DNA sensors (CDS). TLR and RLR signaling results in production of type I interferons (IFNα and -β) and pro-inflammatory cytokines in a cell-specific manner, whereas NLR signaling leads to the production of interleukin-1 family proteins. On the other hand, CLRs are capable of sensing glycans present in viral pathogens, which can induce phagocytic, endocytic, antimicrobial, and pro- inflammatory responses. Peripheral immune sensing of viruses and the ensuing cytokine response can significantly affect the central nervous system (CNS). But viruses can also directly enter the CNS via a multitude of routes, such as the nasal epithelium, along nerve fibers connecting to the periphery and as cargo of infiltrating infected cells passing through the blood brain barrier, triggering innate immune sensing and cytokine responses directly in the CNS. Here, we review mechanisms of viral immune sensing and currently recognized consequences for the CNS of innate immune responses to viruses.
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Affiliation(s)
- Hina Singh
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA; (H.S.); (J.K.)
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jeffrey Koury
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA; (H.S.); (J.K.)
| | - Marcus Kaul
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA; (H.S.); (J.K.)
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
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3
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Bansode YD, Chattopadhyay D, Saha B. Transcriptomic Analysis of Interferon Response in Toll-Like Receptor 2 Ligand-Treated and Herpes Simplex Virus 1-Infected Neurons and Astrocytes. Viral Immunol 2020; 34:256-266. [PMID: 33351727 DOI: 10.1089/vim.2020.0238] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Herpes simplex virus (HSV)-1 infection causes cold sores and keratitis. Upon infection, it forms lesions at the epithelium and enters neurons where it establishes a latent infection. Host innate immune receptor Toll-like receptor (TLR)2 recognizes HSV by sensing its glycoproteins and induces an innate immune response. Upon activation, TLR2 forms a dimer with TLR1, TLR2, or TLR6 and signals inducing cytokines and interferons (IFNs). In this study, we checked the effect of differential activation of TLR2 by using different TLR2 dimer-specific ligands on the anti-HSV-1 innate immune response. We found that TLR2/2 ligand-induced IFN-β in neurons, while IFN-α in astrocytes and these IFNs subsequently induce the expression of IFN stimulatory genes like viperin, Ch25H, OAS2, latent RNase (RNase L), protein kinase R (PKR), and interferon-induced proteins with tetratricopeptide repeats (IFIT) 1. These are the genes with antiviral functions such as blocking viral attachment, protein synthesis, and egress.
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Affiliation(s)
| | - Debprasad Chattopadhyay
- ICMR-National Institute of Traditional Medicine, Belagavi, India.,ICMR-Virus Unit, Kolkata, India
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Abstract
Herpes simplex virus 1 (HSV-1) can be responsible for life-threatening HSV encephalitis (HSE). The mortality rate of patients with HSE who do not receive antiviral treatment is 70%, with most survivors suffering from permanent neurological sequelae. The use of intravenous acyclovir together with improved diagnostic technologies such as PCR and magnetic resonance imaging has resulted in a reduction in the mortality rate to close to 20%. However, 70% of surviving patients still do not recover complete neurological functions. Thus, there is an urgent need to develop more effective treatments for a better clinical outcome. It is well recognized that cerebral damage resulting from HSE is caused by viral replication together with an overzealous inflammatory response. Both of these processes constitute potential targets for the development of innovative therapies against HSE. In this review, we discuss recent progress in therapy that may be used to ameliorate the outcome of patients with HSE, with a particular emphasis on immunomodulatory agents. Ideally, the administration of adjunctive immunomodulatory drugs should be initiated during the rise of the inflammatory response, and its duration should be limited in time to reduce undesired effects. This critical time frame should be optimized by the identification of reliable biomarkers of inflammation.
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Jahanban‐Esfahlan R, Seidi K, Majidinia M, Karimian A, Yousefi B, Nabavi SM, Astani A, Berindan‐Neagoe I, Gulei D, Fallarino F, Gargaro M, Manni G, Pirro M, Xu S, Sadeghi M, Nabavi SF, Shirooie S. Toll‐like receptors as novel therapeutic targets for herpes simplex virus infection. Rev Med Virol 2019; 29:e2048. [DOI: 10.1002/rmv.2048] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/12/2019] [Accepted: 03/19/2019] [Indexed: 12/22/2022]
Affiliation(s)
- Rana Jahanban‐Esfahlan
- Department of Medical Biotechnology, Faculty of Advanced Medical SciencesTabriz University of Medical Sciences Tabriz Iran
- Drug Applied Research CenterTabriz University of Medical Sciences Tabriz Iran
| | - Khaled Seidi
- Immunology Research CenterTabriz University of Medical Sciences Tabriz Iran
| | - Maryam Majidinia
- Solid Tumor Research CenterUrmia University of Medical Sciences Urmia Iran
| | - Ansar Karimian
- Cellular and Molecular Biology Research Center, Health Research InstituteBabol University of Medical Sciences Babol Iran
| | - Bahman Yousefi
- Molecular Medicine Research CenterTabriz University of Medical Sciences Tabriz Iran
- Department of Biochemistry and Clinical Laboratories, Faculty of MedicineTabriz University of Medical Science Tabriz Iran
| | - Seyed Mohammad Nabavi
- Applied Biotechnology Research CenterBaqiyatallah University of Medical Sciences Tehran Iran
| | - Akram Astani
- Department of MicrobiologyShahid Sadoughi University of Medical Sciences Yazd Iran
| | - Ioana Berindan‐Neagoe
- MEDFUTURE ‐Research Center for Advanced Medicine“Iuliu‐Hatieganu” University of Medicine and Pharmacy Cluj‐Napoca Romania
- Research Centerfor Functional Genomics, Biomedicine and Translational Medicine“Iuliu‐Hatieganu” University of Medicine and Pharmacy Cluj‐Napoca Romania
- Department of Functional Genomics and Experimental PathologyThe Oncology Institute “Prof. Dr. Ion Chiricuţă” Cluj‐Napoca Romania
| | - Diana Gulei
- MEDFUTURE ‐Research Center for Advanced Medicine“Iuliu‐Hatieganu” University of Medicine and Pharmacy Cluj‐Napoca Romania
| | | | - Marco Gargaro
- Department of Experimental MedicineUniversity of Perugia Italy
| | - Giorgia Manni
- Department of Experimental MedicineUniversity of Perugia Italy
| | - Matteo Pirro
- Department of MedicineUniversity of Perugia Italy
| | - Suowen Xu
- Aab Cardiovascular Research InstituteUniversity of Rochester Rochester NY USA
| | - Mahmoud Sadeghi
- Department of Transplantation ImmunologyUniversity of Heidelberg Heidelberg Germany
| | - Seyed Fazel Nabavi
- Applied Biotechnology Research CenterBaqiyatallah University of Medical Sciences Tehran Iran
| | - Samira Shirooie
- Department of Pharmacology, Faculty of PharmacyKermanshah University of Medical Sciences Kermanshah Iran
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Tognarelli EI, Palomino TF, Corrales N, Bueno SM, Kalergis AM, González PA. Herpes Simplex Virus Evasion of Early Host Antiviral Responses. Front Cell Infect Microbiol 2019; 9:127. [PMID: 31114761 PMCID: PMC6503643 DOI: 10.3389/fcimb.2019.00127] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 04/10/2019] [Indexed: 12/21/2022] Open
Abstract
Herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2) have co-evolved with humans for thousands of years and are present at a high prevalence in the population worldwide. HSV infections are responsible for several illnesses including skin and mucosal lesions, blindness and even life-threatening encephalitis in both, immunocompetent and immunocompromised individuals of all ages. Therefore, diseases caused by HSVs represent significant public health burdens. Similar to other herpesviruses, HSV-1 and HSV-2 produce lifelong infections in the host by establishing latency in neurons and sporadically reactivating from these cells, eliciting recurrences that are accompanied by viral shedding in both, symptomatic and asymptomatic individuals. The ability of HSVs to persist and recur in otherwise healthy individuals is likely given by the numerous virulence factors that these viruses have evolved to evade host antiviral responses. Here, we review and discuss molecular mechanisms used by HSVs to evade early innate antiviral responses, which are the first lines of defense against these viruses. A comprehensive understanding of how HSVs evade host early antiviral responses could contribute to the development of novel therapies and vaccines to counteract these viruses.
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Affiliation(s)
- Eduardo I Tognarelli
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Tomás F Palomino
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nicolás Corrales
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Susan M Bueno
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alexis M Kalergis
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Endocrinología, Facultad de Medicina, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo A González
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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Koujah L, Suryawanshi RK, Shukla D. Pathological processes activated by herpes simplex virus-1 (HSV-1) infection in the cornea. Cell Mol Life Sci 2019; 76:405-419. [PMID: 30327839 PMCID: PMC6349487 DOI: 10.1007/s00018-018-2938-1] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 10/03/2018] [Accepted: 10/08/2018] [Indexed: 12/13/2022]
Abstract
Herpes simplex virus type-1 (HSV-1) is a ubiquitous pathogen that infects a large majority of the human population worldwide. It is also a leading cause of infection-related blindness in the developed world. HSV-1 infection of the cornea begins with viral entry into resident cells via a multistep process that involves interaction of viral glycoproteins and host cell surface receptors. Once inside, HSV-1 infection induces a chronic immune-inflammatory response resulting in corneal scarring, thinning and neovascularization. This leads to development of various ocular diseases such as herpes stromal keratitis, resulting in visual impairment and eventual blindness. HSV-1 can also invade the central nervous system and lead to encephalitis, a relatively common cause of sporadic fetal encephalitis worldwide. In this review, we discuss the pathological processes activated by corneal HSV-1 infection and existing antiviral therapies as well as novel therapeutic options currently under development.
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Affiliation(s)
- Lulia Koujah
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 W. Taylor St, Chicago, IL, 60612, USA
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Rahul K Suryawanshi
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 W. Taylor St, Chicago, IL, 60612, USA
| | - Deepak Shukla
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 W. Taylor St, Chicago, IL, 60612, USA.
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, 60612, USA.
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Dendritic cells in the cornea during Herpes simplex viral infection and inflammation. Surv Ophthalmol 2018; 63:565-578. [DOI: 10.1016/j.survophthal.2017.11.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 11/05/2017] [Accepted: 11/06/2017] [Indexed: 12/24/2022]
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9
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Skouboe MK, Knudsen A, Reinert LS, Boularan C, Lioux T, Perouzel E, Thomsen MK, Paludan SR. STING agonists enable antiviral cross-talk between human cells and confer protection against genital herpes in mice. PLoS Pathog 2018; 14:e1006976. [PMID: 29608601 PMCID: PMC5897032 DOI: 10.1371/journal.ppat.1006976] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 04/12/2018] [Accepted: 03/17/2018] [Indexed: 01/27/2023] Open
Abstract
In recent years, there has been an increasing interest in immunomodulatory therapy as a means to treat various conditions, including infectious diseases. For instance, Toll-like receptor (TLR) agonists have been evaluated for treatment of genital herpes. However, although the TLR7 agonist imiquimod was shown to have antiviral activity in individual patients, no significant effects were observed in clinical trials, and the compound also exhibited significant side effects, including local inflammation. Cytosolic DNA is detected by the enzyme cyclic GMP-AMP (2’3’-cGAMP) synthase (cGAS) to stimulate antiviral pathways, mainly through induction of type I interferon (IFN)s. cGAS is activated upon DNA binding to produce the cyclic dinucleotide (CDN) 2’3’-cGAMP, which in turn binds and activates the adaptor protein Stimulator of interferon genes (STING), thus triggering type I IFN expression. In contrast to TLRs, STING is expressed broadly, including in epithelial cells. Here we report that natural and non-natural STING agonists strongly induce type I IFNs in human cells and in mice in vivo, without stimulating significant inflammatory gene expression. Systemic treatment with 2’3’-cGAMP reduced genital herpes simplex virus (HSV) 2 replication and improved the clinical outcome of infection. More importantly, local application of CDNs at the genital epithelial surface gave rise to local IFN activity, but only limited systemic responses, and this treatment conferred total protection against disease in both immunocompetent and immunocompromised mice. In direct comparison between CDNs and TLR agonists, only CDNs acted directly on epithelial cells, hence allowing a more rapid and IFN-focused immune response in the vaginal epithelium. Thus, specific activation of the STING pathway in the vagina evokes induction of the IFN system but limited inflammatory responses to allow control of HSV2 infections in vivo. Herpes simplex virus (HSV)-2 is the leading cause of genital ulcers, and HSV-2 infection has also been reported to amplify HIV-transmission. So far, all attempts at making an effective anti-HSV2 vaccine have failed. In recent years, there has been an increasing interest in immunomodulatory therapy as a means to treat infections. Although the TLR7 agonist imiquimod has been shown to have antiviral activity in individual patients, no significant effects were observed in clinical trials, and the compound also exhibited significant side effects including local inflammation. Type I interferon (IFN)s are key players in antiviral defense, and it is now known that the DNA sensor cyclic GMP-AMP synthase produces the cyclic di-nucleotide (CDN) 2’3’-cyclic GMP-AMP (cGAMP), which activates the adaptor protein STING to induce IFN expression. In this work we show that natural and non-natural CDNs activate strong type I IFN responses in vivo without stimulating significant expression of genes driven by the transcription factor NF-κB, which induces inflammation. Application of CDNs at epithelial surfaces gave rise to local IFN activity, but only limited systemic responses. Importantly, all tested treatment regimens, strongly reduced replication of HSV-2 in a model for genital herpes, and significantly reduced development of disease. Finally, when comparing to TLR agonists, CDNs showed the best profile with strong IFN response specifically in the epithelial cells and limited induction of inflammation.
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Affiliation(s)
| | - Alice Knudsen
- Department of Biomedicine, Aarhus University, Denmark
| | | | | | | | | | - Martin K. Thomsen
- Department of Clinical Medicine, Aarhus University, Denmark
- * E-mail: (SRP); (MKT)
| | - Søren R. Paludan
- Department of Biomedicine, Aarhus University, Denmark
- * E-mail: (SRP); (MKT)
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Michelini FM, Bueno CA, Molinari AM, Galigniana MD, Galagovsky LR, Alché LE, Ramírez JA. Synthetic stigmastanes with dual antiherpetic and immunomodulating activities inhibit ERK and Akt signaling pathways without binding to glucocorticoid receptors. Biochim Biophys Acta Gen Subj 2016; 1860:129-39. [DOI: 10.1016/j.bbagen.2015.10.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 10/07/2015] [Accepted: 10/23/2015] [Indexed: 01/09/2023]
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Valacyclovir combined with artesunate or rapamycin improves the outcome of herpes simplex virus encephalitis in mice compared to antiviral therapy alone. Antiviral Res 2015; 123:105-13. [PMID: 26374952 DOI: 10.1016/j.antiviral.2015.09.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 09/10/2015] [Accepted: 09/11/2015] [Indexed: 11/20/2022]
Abstract
Despite antiviral therapy, the mortality rate of herpes simplex virus encephalitis (HSE) remains high and many surviving patients harbor neurological sequelae. Although viral replication is responsible for substantial neurological damages, an exaggerated inflammatory response could also contribute to this process. Artesunate (ART) and rapamycin (RAPA) have shown some benefits in the treatment of herpes simplex virus infections. Herein, we evaluated the benefit of combining ART or RAPA with valacyclovir (VACV) in a murine model of HSE. Infected mice were treated with VACV (1mg/mL in drinking water) from day 3 post-infection (p.i.) combined or not with daily intraperitoneal administration of ART (30mg/kg) or RAPA (20mg/kg) from days 4 to 13 p.i. Viral load, infectious titers, cytokine and chemokine levels were measured in brain homogenates on days 5, 7 and 9. The survival rates of mice treated with VACV and ART or RAPA were higher than with VACV alone (71.9% versus 43.2% for ART and 66.7% versus 43.2% for RAPA; both P⩽0.05) but no significant difference was seen in the brain viral loads. Levels of IL-1β, IL-2 (both P⩽0.05), IL-6, IFN-γ (both P⩽0.01), CCL2 (P⩽0.01), CCL3 and CCL4 (both P⩽0.05) were reduced in mice treated with VACV combined with ART versus VACV alone. Levels of IL-6, IL-1β and IFN-γ slightly increased on day 7 in mice treated with VACV combined with RAPA compared to VACV alone and then decreased on day 9. Our results suggest that immunomodulatory compounds such as ART or RAPA could benefit antiviral therapy in HSE.
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Piret J, Boivin G. Innate immune response during herpes simplex virus encephalitis and development of immunomodulatory strategies. Rev Med Virol 2015. [PMID: 26205506 DOI: 10.1002/rmv.1848] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Herpes simplex viruses are large double-stranded DNA viruses. These viruses have the ability to establish a lifelong latency in sensory ganglia and to invade and replicate in the CNS. Apart from relatively benign mucosal infections, HSV is responsible for severe illnesses including HSV encephalitis (HSE). HSE is the most common cause of sporadic, potentially fatal viral encephalitis in Western countries. If left untreated, the mortality rate associated with HSE is approximately 70%. Despite antiviral therapy, the mortality is still higher than 30%, and almost 60% of surviving individuals develop neurological sequelae. It is suggested that direct virus-related and indirect immune-mediated mechanisms contribute to the damages occurring in the CNS during HSE. In this manuscript, we describe the innate immune response to HSV, the development of HSE in mice knock-out for proteins of the innate immune system as well as inherited deficiencies in key components of the signaling pathways involved in the production of type I interferon that could predispose individuals to develop HSE. Finally, we review several immunomodulatory strategies aimed at modulating the innate immune response at a critical time after infection that were evaluated in mouse models and could be combined with antiviral therapy to improve the prognosis of HSE. In conclusion, the cerebral innate immune response that develops during HSE is a "double-edged sword" as it is critical to control viral replication in the brain early after infection, but, if left uncontrolled, may also result in an exaggerated inflammatory response that could be detrimental to the host.
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Affiliation(s)
- Jocelyne Piret
- Research Center in Infectious Diseases, CHU de Québec and Laval University, Quebec City, Quebec, Canada
| | - Guy Boivin
- Research Center in Infectious Diseases, CHU de Québec and Laval University, Quebec City, Quebec, Canada
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Evasion of early antiviral responses by herpes simplex viruses. Mediators Inflamm 2015; 2015:593757. [PMID: 25918478 PMCID: PMC4396904 DOI: 10.1155/2015/593757] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 03/10/2015] [Indexed: 02/06/2023] Open
Abstract
Besides overcoming physical constraints, such as extreme temperatures, reduced humidity, elevated pressure, and natural predators, human pathogens further need to overcome an arsenal of antimicrobial components evolved by the host to limit infection, replication and optimally, reinfection. Herpes simplex virus-1 (HSV-1) and herpes simplex virus-2 (HSV-2) infect humans at a high frequency and persist within the host for life by establishing latency in neurons. To gain access to these cells, herpes simplex viruses (HSVs) must replicate and block immediate host antiviral responses elicited by epithelial cells and innate immune components early after infection. During these processes, infected and noninfected neighboring cells, as well as tissue-resident and patrolling immune cells, will sense viral components and cell-associated danger signals and secrete soluble mediators. While type-I interferons aim at limiting virus spread, cytokines and chemokines will modulate resident and incoming immune cells. In this paper, we discuss recent findings relative to the early steps taking place during HSV infection and replication. Further, we discuss how HSVs evade detection by host cells and the molecular mechanisms evolved by these viruses to circumvent early antiviral mechanisms, ultimately leading to neuron infection and the establishment of latency.
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Abstract
Alphaherpesviruses include human and animal pathogens, such as herpes simplex virus type 1, which establish life-long latent infections with episodes of recurrence. The immunocompetence of the infected host is an important determinant for the outcome of infections with alphaherpesviruses. Recognition of pathogen-associated molecular patterns by pattern recognition receptors is an essential, early step in the innate immune response to pathogens. In recent years, it has been discovered that herpesvirus DNA is a strong inducer of the innate immune system. The viral genome can be recognized in endosomes by TLR9, as well as intracellularly by a variety of DNA sensors, the best documented being cGAS, RNA Pol III, IFI16, and AIM2. These DNA sensors use converging signaling pathways to activate transcription factors, such as IRF3 and NF-κB, which induce the expression of type I interferons and other inflammatory cytokines and activate the inflammasome. This review summarizes the recent literature on the innate sensing of alphaherpesvirus DNA, the mechanisms of activation of the different sensors, their mechanisms of signal transduction, their physiological role in defense against herpesvirus infection, and how alphaherpesviruses seek to evade these responses to allow establishment and maintenance of infection.
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Affiliation(s)
- Stefanie Luecke
- Graduate School of Life Sciences, Universiteit Utrecht, Utrecht, The Netherlands
| | - Søren R Paludan
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Aarhus Research Center for Innate Immunology, Aarhus University, Aarhus, Denmark.
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Natural and semisynthetic diterpenoids with antiviral and immunomodulatory activities block the ERK signaling pathway. Med Microbiol Immunol 2014; 204:575-84. [DOI: 10.1007/s00430-014-0383-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 10/31/2014] [Indexed: 12/01/2022]
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16
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Animal models of herpes simplex virus immunity and pathogenesis. J Neurovirol 2014; 21:8-23. [PMID: 25388226 DOI: 10.1007/s13365-014-0302-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 10/07/2014] [Accepted: 10/27/2014] [Indexed: 12/20/2022]
Abstract
Herpes simplex viruses are ubiquitous human pathogens represented by two distinct serotypes: herpes simplex virus (HSV) type 1 (HSV-1); and HSV type 2 (HSV-2). In the general population, adult seropositivity rates approach 90% for HSV-1 and 20-25% for HSV-2. These viruses cause significant morbidity, primarily as mucosal membrane lesions in the form of facial cold sores and genital ulcers, with much less common but more severe manifestations causing death from encephalitis. HSV infections in humans are difficult to study in many cases because many primary infections are asymptomatic. Moreover, the neurotropic properties of HSV make it much more difficult to study the immune mechanisms controlling reactivation of latent infection within the corresponding sensory ganglia and crossover into the central nervous system of infected humans. This is because samples from the nervous system can only be routinely obtained at the time of autopsy. Thus, animal models have been developed whose use has led to a better understanding of multiple aspects of HSV biology, molecular biology, pathogenesis, disease, and immunity. The course of HSV infection in a spectrum of animal models depends on important experimental parameters including animal species, age, and genotype; route of infection; and viral serotype, strain, and dose. This review summarizes the animal models most commonly used to study HSV pathogenesis and its establishment, maintenance, and reactivation from latency. It focuses particularly on the immune response to HSV during acute primary infection and the initial invasion of the ganglion with comparisons to the events governing maintenance of viral latency.
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Toll-like receptor expression in the nervous system of bovine alpha-herpesvirus-infected calves. Res Vet Sci 2014; 97:422-9. [DOI: 10.1016/j.rvsc.2014.06.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 05/29/2014] [Accepted: 06/28/2014] [Indexed: 12/25/2022]
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Sauter MM, Gauger JJL, Brandt CR. Oligonucleotides designed to inhibit TLR9 block Herpes simplex virus type 1 infection at multiple steps. Antiviral Res 2014; 109:83-96. [PMID: 24995383 DOI: 10.1016/j.antiviral.2014.06.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 06/10/2014] [Accepted: 06/23/2014] [Indexed: 01/09/2023]
Abstract
Herpes simplex virus type 1 (HSV-1) is an important human pathogen which requires activation of nuclear factor-kappa B (NFκB) during its replication cycle. The persistent nature of HSV-1 infection, and the emergence of drug-resistant strains, highlights the importance of research to develop new antiviral agents. Toll-like receptors (TLRs) play a prominent role during the early antiviral response by recognizing viral nucleic acid and gene products, activating NFκB, and stimulating the production of inflammatory cytokines. We demonstrate a significant effect on HSV-1 replication in ARPE-19 and Vero cells when oligonucleotides designed to inhibit TLR9 are added 2h prior to infection. A greater than 90% reduction in the yield of infectious virus was achieved at oligonucleotide concentrations of 10-20 μM. TLR9 inhibitory oligonucleotides prevented expression of essential immediate early herpes gene products as determined by immunofluorescence microscopy and Western blotting. TLR9 oligonucleotides also interfered with viral attachment and entry. A TLR9 inhibitory oligonucleotide containing five adjacent guanosine residues (G-ODN) exhibited virucidal activity and inhibited HSV-1 replication when added post-infection. The antiviral effect of the TLR9 inhibitory oligonucleotides did not depend on the presence of TLR9 protein, suggesting a mechanism of inhibition that is not TLR9 specific. TLR9 inhibitory oligonucleotides also reduced NFκB activity in nuclear extracts. Studies using these TLR inhibitors in the context of viral infection should be interpreted with caution.
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Affiliation(s)
- Monica M Sauter
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53706, United States.
| | - Joshua J L Gauger
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, United States.
| | - Curtis R Brandt
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53706, United States; Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, United States; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53706, United States.
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Nath A, Tyler KL. Novel approaches and challenges to treatment of central nervous system viral infections. Ann Neurol 2013; 74:412-22. [PMID: 23913580 PMCID: PMC4052367 DOI: 10.1002/ana.23988] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/23/2013] [Accepted: 07/29/2013] [Indexed: 12/14/2022]
Abstract
Existing and emerging viral central nervous system (CNS) infections are major sources of human morbidity and mortality. Treatments of proven efficacy are currently limited predominantly to herpesviruses and human immunodeficiency virus (HIV). Development of new therapies has been hampered by the lack of appropriate animal model systems for some important viruses and by the difficulty in conducting human clinical trials for diseases that may be rare, or in the case of arboviral infections, often have variable seasonal and geographic incidence. Nonetheless, many novel approaches to antiviral therapy are available, including candidate thiazolide and pyrazinecarboxamide derivatives with potential broad‐spectrum antiviral efficacy. New herpesvirus drugs include viral helicase‐primase and terminase inhibitors. The use of antisense oligonucleotides and other strategies to interfere with viral RNA translation has shown efficacy in experimental models of CNS viral disease. Identifying specific molecular targets within viral replication cycles has led to many existing antiviral agents and will undoubtedly continue to be the basis of future drug design. A promising new area of research involves therapies based on enhanced understanding of host antiviral immune responses. Toll‐like receptor agonists and drugs that inhibit specific cytokines as well as interferon preparations have all shown potential therapeutic efficacy. Passive transfer of virus‐specific cytotoxic T lymphocytes has been used in humans and may provide an effective therapy for some herpesvirus infections and potentially for progressive multifocal leukoencephalopathy. Humanized monoclonal antibodies directed against specific viral proteins have been developed and in several cases evaluated in humans in settings including West Nile virus and HIV infection and in pre‐exposure prophylaxis for rabies. Ann Neurol 2013;74:412–422
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Affiliation(s)
- Avindra Nath
- Section of Infections of the Nervous Systems, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD
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Ramos-Estebanez C, Lizarraga KJ, Merenda A. A systematic review on the role of adjunctive corticosteroids in herpes simplex virus encephalitis: is timing critical for safety and efficacy? Antivir Ther 2013; 19:133-9. [DOI: 10.3851/imp2683] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2013] [Indexed: 10/26/2022]
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