RESUMO
Maternal anti-respiratory syncytial virus (RSV) antibodies acquired by the fetus through the placenta protect neonates from RSV disease through the first weeks of life. In the cotton rat model of RSV infections, we previously reported that immunization of dams during pregnancy with virus-like particles assembled with mutation stabilized pre-fusion F protein as well as the wild type G protein resulted in robust protection of their offspring from RSV challenge. Here we describe the durability of those protective responses in dams, the durability of protection in offspring, and the transfer of that protection to offspring of two consecutive pregnancies without a second boost immunization. We report that four weeks after birth, offspring of the first pregnancy were significantly protected from RSV replication in both lungs and nasal tissues after RSV challenge, but protection was reduced in pups at 6 weeks after birth. However, the overall protection of offspring of the second pregnancy was considerably reduced, even at four weeks of age. This drop in protection occurred even though the levels of total anti-pre-F IgG and neutralizing antibody titers in dams remained at similar, high levels before and after the second pregnancy. The results are consistent with an evolution of antibody properties in dams to populations less efficiently transferred to offspring or the less efficient transfer of antibodies in elderly dams.
Assuntos
Anticorpos Antivirais/imunologia , Infecções por Vírus Respiratório Sincicial/prevenção & controle , Vacinas contra Vírus Sincicial Respiratório/imunologia , Vírus Sincicial Respiratório Humano/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Feminino , Humanos , Imunização , Pulmão/imunologia , Pulmão/virologia , Nariz/imunologia , Nariz/virologia , Gravidez , Infecções por Vírus Respiratório Sincicial/virologia , SigmodontinaeRESUMO
Demyelinating central nervous system (CNS) disorders like multiple sclerosis (MS) and acute disseminated encephalomyelitis (ADEM) have been difficult to study and treat due to the lack of understanding of their etiology. Numerous cases point to the link between herpes simplex virus (HSV) infection and multifocal CNS demyelination in humans; however, convincing evidence from animal models has been missing. In this work, we found that HSV-1 infection of the cotton rat Sigmodon hispidus via a common route (lip abrasion) can cause multifocal CNS demyelination and inflammation. Remyelination occurred shortly after demyelination in HSV-1-infected cotton rats but could be incomplete, resulting in "scars," further supporting an association between HSV-1 infection and multifocal demyelinating disorders. Virus was detected sequentially in the lip, trigeminal ganglia, and brain of infected animals. Brain pathology developed primarily on the ipsilateral side of the brain stem, in the cerebellum, and contralateral side of the forebrain/midbrain, suggesting that the changes may ascend along the trigeminal lemniscus pathway. Neurologic defects occasionally detected in infected animals (e.g., defective whisker touch and blink responses and compromised balance) could be representative of the brain stem/cerebellum dysfunction. Immunization of cotton rats with a split HSV-1 vaccine protected animals against viral replication and brain pathology, suggesting that vaccination against HSV-1 may protect against demyelinating disorders.IMPORTANCE Our work demonstrates for the first time a direct association between infection with herpes simplex virus 1, a ubiquitous human pathogen generally associated with facial cold sores, and multifocal brain demyelination in an otherwise normal host, the cotton rat Sigmodon hispidus For a long time, demyelinating diseases were considered to be autoimmune in nature and were studied by indirect methods, such as immunizing animals with myelin components or feeding them toxic substances that induce demyelination. Treatment against demyelinating diseases has been elusive, partially because of their unknown etiology. This work provides the first experimental evidence for the role of HSV-1 as the etiologic agent of multifocal brain demyelination in a normal host and suggests that vaccination against HSV-1 can help to combat demyelinating disorders.
Assuntos
Doenças Desmielinizantes/prevenção & controle , Encefalite/prevenção & controle , Vacinas contra o Vírus do Herpes Simples/administração & dosagem , Herpes Simples/prevenção & controle , Herpesvirus Humano 1/efeitos dos fármacos , Animais , Tronco Encefálico/efeitos dos fármacos , Tronco Encefálico/imunologia , Tronco Encefálico/patologia , Tronco Encefálico/virologia , Cerebelo/efeitos dos fármacos , Cerebelo/imunologia , Cerebelo/patologia , Cerebelo/virologia , Doenças Desmielinizantes/imunologia , Doenças Desmielinizantes/patologia , Doenças Desmielinizantes/virologia , Modelos Animais de Doenças , Encefalite/imunologia , Encefalite/patologia , Encefalite/virologia , Feminino , Herpes Simples/imunologia , Herpes Simples/patologia , Herpes Simples/virologia , Herpesvirus Humano 1/imunologia , Herpesvirus Humano 1/patogenicidade , Humanos , Masculino , Prosencéfalo/efeitos dos fármacos , Prosencéfalo/imunologia , Prosencéfalo/patologia , Prosencéfalo/virologia , Sigmodontinae , Gânglio Trigeminal/efeitos dos fármacos , Gânglio Trigeminal/imunologia , Gânglio Trigeminal/patologia , Gânglio Trigeminal/virologia , Vacinação , Carga Viral/efeitos dos fármacosRESUMO
Maternal vaccination may be the most effective and safest approach to the protection of infants from respiratory syncytial virus (RSV) infection, a severe acute lower respiratory tract disease in infants and young children worldwide. We previously compared five different virus-like particle (VLP)-associated, mutation-stabilized prefusion F (pre-F) proteins, including the prototype DS-Cav1 F VLPs. We showed that alternative versions of prefusion F proteins have different conformations and induce different populations of anti-F protein antibodies. Two of these alternative pre-F VLPs, the UC-2 F and UC-3 F VLPs, stimulated in mice higher titers of neutralizing antibodies than DS-Cav1 F VLPs (M. L. Cullen, R. M. Schmidt, M. G. Torres, A. A. Capoferri, et al., Vaccines 7:21-41, 2019, https://doi.org/10.3390/vaccines7010021). Here we describe a comparison of these two pre-F VLPs with DS-Cav1 F VLPs as maternal vaccines in cotton rats and report that UC-3 F VLPs significantly increased the neutralizing antibody (NAb) titers in pregnant dams compared to DS-Cav1 F VLPs. The neutralizing antibody titers in the sera of the offspring of the dams immunized with UC-3 F VLPs were significantly higher than those in the sera of the offspring of dams immunized with DS-Cav1 VLPs. This increase in serum NAb titers translated to a 6- to 40-fold lower virus titer in the lungs of the RSV-challenged offspring of dams immunized with UC-3 F VLPs than in the lungs of the RSV-challenged offspring of dams immunized with DS-Cav1 F VLPs. Importantly, the offspring of UC-3 F VLP-immunized dams showed significant protection from lung pathology and from induction of inflammatory lung cytokine mRNA expression after RSV challenge. Immunization with UC-3 F VLPs also induced durable levels of high-titer neutralizing antibodies in dams.IMPORTANCE Respiratory syncytial virus (RSV) is a significant human pathogen severely impacting neonates and young children, but no vaccine exists to protect this vulnerable population. Furthermore, direct vaccination of neonates is likely ineffective due to the immaturity of their immune system, and neonate immunization is potentially unsafe. Maternal vaccination may be the best and safest approach to the protection of neonates through the passive transfer of maternal neutralizing antibodies in utero to the fetus after maternal immunization. Here we report that immunization of pregnant cotton rats, a surrogate model for human maternal immunization, with novel RSV virus-like particle (VLP) vaccine candidates containing stabilized prefusion RSV F proteins provides significant levels of protection of the offspring of immunized dams from RSV challenge. We also found that antibodies induced by VLPs containing different versions of the prefusion F protein varied by 40-fold in the extent of protection provided to the offspring of vaccinated dams upon RSV challenge.
Assuntos
Infecções por Vírus Respiratório Sincicial/imunologia , Infecções por Vírus Respiratório Sincicial/prevenção & controle , Vacinas contra Vírus Sincicial Respiratório/imunologia , Vírus Sincicial Respiratório Humano/imunologia , Vacinas de Partículas Semelhantes a Vírus/imunologia , Proteínas Virais de Fusão/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Linhagem Celular , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Feminino , Glicoproteínas/imunologia , Humanos , Imunização , Pulmão/imunologia , Pulmão/patologia , RNA Mensageiro/metabolismo , Vírus Sincicial Respiratório Humano/genética , Sigmodontinae , Vacinação , Proteínas Virais de Fusão/genéticaRESUMO
UNLABELLED: Subunit vaccines based on the herpes simplex virus 2 (HSV-2) glycoprotein D (gD-2) have been the major focus of HSV-2 vaccine development for the past 2 decades. Based on the promising data generated in the guinea pig model, a formulation containing truncated gD-2, aluminum salt, and MPL (gD/AS04) advanced to clinical trials. The results of these trials, however, were unexpected, as the vaccine protected against HSV-1 infection but not against HSV-2. To address this discrepancy, we developed a Depot medroxyprogesterone acetate (DMPA)-treated cotton rat Sigmodon hispidus model of HSV-2 and HSV-1 genital infection. The severity of HSV-1 genital herpes was less than that of HSV-2 genital herpes in cotton rats, and yet the model allowed for comparative evaluation of gD/AS04 immunogenicity and efficacy. Cotton rats were intramuscularly vaccinated using a prime boost strategy with gD/AS04 (Simplirix vaccine) or control vaccine formulation (hepatitis B vaccine FENDrix) and subsequently challenged intravaginally with HSV-2 or HSV-1. The gD/AS04 vaccine was immunogenic in cotton rats and induced serum IgG directed against gD-2 and serum HSV-2 neutralizing antibodies but failed to efficiently protect against HSV-2 disease or to decrease the HSV-2 viral load. However, gD/AS04 significantly reduced vaginal titers of HSV-1 and better protected animals against HSV-1 compared to HSV-2 genital disease. The latter finding is generally consistent with the clinical outcome of the Herpevac trial of Simplirix. Passive transfer of serum from gD/AS04-immunized cotton rats conferred stronger protection against HSV-1 genital disease. These findings suggest the need for alternative vaccine strategies and the identification of new correlates of protection. IMPORTANCE: In spite of the high health burden of genital herpes, there is still no effective intervention against the disease. The significant gap in knowledge on genital herpes pathogenesis has been further highlighted by the recent failure of GSK HSV-2 vaccine Simplirix (gD/AS04) to protect humans against HSV-2 and the surprising finding that the vaccine protected against HSV-1 genital herpes instead. In this study, we report that gD/AS04 has higher efficacy against HSV-1 compared to HSV-2 genital herpes in the novel DMPA-synchronized cotton rat model of HSV-1 and HSV-2 infection. The findings help explain the results of the Simplirix trial.
Assuntos
Modelos Animais de Doenças , Herpes Genital/prevenção & controle , Herpesvirus Humano 1/efeitos dos fármacos , Herpesvirus Humano 2/efeitos dos fármacos , Sigmodontinae , Proteínas do Envelope Viral/farmacologia , Vacinas Virais/farmacologia , Hidróxido de Alumínio , Compostos de Anilina , Animais , Avaliação Pré-Clínica de Medicamentos , Ensaio de Imunoadsorção Enzimática , Feminino , Injeções Intramusculares , Lipídeo A/análogos & derivados , Vacinas de Subunidades Antigênicas/administração & dosagem , Vacinas de Subunidades Antigênicas/farmacologia , Proteínas do Envelope Viral/administração & dosagem , Vacinas Virais/administração & dosagemRESUMO
The cotton rat Sigmodon hispidus is a New World rodent that has become an important model of respiratory syncytial virus (RSV) infection. This small animal is relatively permissive to RSV and can be infected throughout life. It recapitulates the pathology associated with the FI-RSV vaccine-enhanced disease, the phenomenon of maternally transmitted immunity and the ability of passive immunity to suppress efficacy of RSV vaccines. Different highly susceptible human cohort scenarios have been modeled in the cotton rat, including RSV disease in infants, elderly, and immunosuppressed individuals. The cotton rat has accurately predicted efficacy and dose of antibody immunoprophylaxis, and the lack of efficacy of antibody immunotherapy for disease treatment. With the recent development of molecular reagents and tools for the model, the cotton rat is an important model of RSV infection to consider for vaccine and drug testing, and will continue to advance our understanding of RSV disease pathogenesis.
Assuntos
Anticorpos Antivirais/imunologia , Imunidade Materno-Adquirida , Infecções por Vírus Respiratório Sincicial/prevenção & controle , Infecções por Vírus Respiratório Sincicial/veterinária , Vacinas contra Vírus Sincicial Respiratório/imunologia , Vírus Sincicial Respiratório Humano/imunologia , Idoso , Animais , Animais Recém-Nascidos , Modelos Animais de Doenças , Humanos , Hospedeiro Imunocomprometido , Lactente , Infecções por Vírus Respiratório Sincicial/imunologia , Infecções por Vírus Respiratório Sincicial/fisiopatologia , Vacinas contra Vírus Sincicial Respiratório/administração & dosagem , Vacinas contra Vírus Sincicial Respiratório/efeitos adversos , Vírus Sincicial Respiratório Humano/genética , Sigmodontinae , Vacinas Atenuadas , Proteínas Virais de Fusão/genética , Proteínas Virais de Fusão/imunologiaRESUMO
Numerous enveloped viruses, such as coronaviruses, influenza, and respiratory syncytial virus (RSV), utilize class I fusion proteins for cell entry. During this process, the proteins transition from a prefusion to a postfusion state, undergoing substantial and irreversible conformational changes. The prefusion conformation has repeatedly shown significant potential in vaccine development. However, the instability of this state poses challenges for its practical application in vaccines. While non-native disulfides have been effective in maintaining the prefusion structure, identifying stabilizing disulfide bonds remains an intricated task. Here, we present a general computational approach to systematically identify prefusion-stabilizing disulfides. Our method assesses the geometric constraints of disulfide bonds and introduces a ranking system to estimate their potential in stabilizing the prefusion conformation. We found, for the RSV F protein, that disulfides restricting the initial stages of the conformational switch can offer higher stability to the prefusion state than those preventing unfolding at a later stage. The implementation of our algorithm on the RSV F protein led to the discovery of prefusion-stabilizing disulfides, providing evidence that supports our hypothesis. Furthermore, the evaluation of our top design as a vaccine candidate in a cotton rat model demonstrated robust protection against RSV infection, highlighting the potential of our approach for vaccine development.
RESUMO
Numerous enveloped viruses, such as coronaviruses, influenza, and respiratory syncytial virus (RSV), utilize class I fusion proteins for cell entry. During this process, the proteins transition from a prefusion to a postfusion state, undergoing substantial and irreversible conformational changes. The prefusion conformation has repeatedly shown significant potential in vaccine development. However, the instability of this state poses challenges for its practical application in vaccines. While non-native disulfides have been effective in maintaining the prefusion structure, identifying stabilizing disulfide bonds remains an intricate task. Here, we present a general computational approach to systematically identify prefusion-stabilizing disulfides. Our method assesses the geometric constraints of disulfide bonds and introduces a ranking system to estimate their potential in stabilizing the prefusion conformation. We hypothesized that disulfides restricting the initial stages of the conformational switch could offer higher stability to the prefusion state than those preventing unfolding at a later stage. The implementation of our algorithm on the RSV F protein led to the discovery of prefusion-stabilizing disulfides that supported our hypothesis. Furthermore, the evaluation of our top design as a vaccine candidate in a cotton rat model demonstrated robust protection against RSV infection, highlighting the potential of our approach for vaccine development.
Assuntos
Dissulfetos , Proteínas Virais de Fusão , Dissulfetos/química , Animais , Proteínas Virais de Fusão/imunologia , Proteínas Virais de Fusão/química , Humanos , Infecções por Vírus Respiratório Sincicial/imunologia , Infecções por Vírus Respiratório Sincicial/prevenção & controle , Infecções por Vírus Respiratório Sincicial/virologia , Estabilidade Proteica , Desenho Assistido por Computador , Conformação Proteica , Vírus Sinciciais Respiratórios/imunologia , Vacinas contra Vírus Sincicial Respiratório/imunologia , Ratos , Modelos MolecularesRESUMO
Alzheimer's disease (AD) and multiple sclerosis (MS) are two CNS disorders affecting millions of people, for which no cure is available. AD is usually diagnosed in individuals age 65 and older and manifests with accumulation of beta amyloid in the brain. MS, a demyelinating disorder, is most commonly diagnosed in its relapsing-remitting (RRMS) form in young adults (age 20-40). The lack of success in a number of recent clinical trials of immune- or amyloid-targeting therapeutics emphasizes our incomplete understanding of their etiology and pathogenesis. Evidence is accumulating that infectious agents such as viruses may contribute either directly or indirectly. With the emerging recognition that demyelination plays a role in risk and progression of AD, we propose that MS and AD are connected by sharing a common environmental factor (a viral infection such as HSV-1) and pathology (demyelination). In the viral DEmyelinating Neurodegenerative Trigger (vDENT) model of AD and MS, the initial demyelinating viral (e.g., HSV-1) infection provokes the first episode of demyelination that occurs early in life, with subsequent virus reactivations/demyelination and associated immune/inflammatory attacks resulting in RRMS. The accumulating damage and/or virus progression deeper into CNS leads to amyloid dysfunction, which, combined with the inherent age-related defects in remyelination, propensity for autoimmunity, and increased blood-brain barrier permeability, leads to the development of AD dementia later in life. Preventing or diminishing vDENT event(s) early in life, thus, may have a dual benefit of slowing down the progression of MS and reducing incidence of AD at an older age.
RESUMO
Human metapneumovirus (hMPV) is an important cause of respiratory disease in immunocompromised individuals, yet hMPV infection has not been modeled before in immunocompromised animals. In this work, cotton rats S. hispidus immunosuppressed by cyclophosphamide were infected with hMPV, and viral replication and pulmonary inflammation in these animals were compared to those in normal hMPV-infected S. hispidus. The efficacy of prophylactic and therapeutic administration of the anti-hMPV antibody MPV467 was also evaluated. Immunosuppressed animals had higher pulmonary and nasal titers of hMPV on day 5 post-infection compared to normal animals, and large amounts of hMPV were still present in the respiratory tract of immunosuppressed animals on days 7 and 9 post-infection, indicating prolonged viral replication. Immunosuppression was accompanied by reduced pulmonary histopathology in hMPV-infected cotton rats compared to normal animals; however, a delayed increase in pathology and pulmonary chemokine expression was seen in immunosuppressed cotton rats. Prophylactic and therapeutic MPV467 treatments protected both upper and lower respiratory tracts against hMPV infection. The lung pathology and pulmonary expression of IP-10 and MIP-1α mRNA were reduced by therapeutic MPV467 administration. These results indicate that immunosuppressed cotton rats represent a useful model for studying hMPV pathogenesis and for evaluating therapeutics that could alleviate hMPV-induced disease in immunocompromised subjects.
Assuntos
Hospedeiro Imunocomprometido , Metapneumovirus , Infecções por Paramyxoviridae , Sigmodontinae , Animais , Humanos , Quimiocina CCL3 , Hospedeiro Imunocomprometido/imunologia , Terapia de Imunossupressão , Infecções por Paramyxoviridae/imunologia , Infecções por Paramyxoviridae/virologia , Sigmodontinae/imunologia , Sigmodontinae/virologia , Modelos Animais de DoençasRESUMO
Respiratory syncytial virus (RSV) is a significant threat to elderly populations and repeated infections that occur throughout life are poorly protective. To assess the role of prior RSV infections as well as elderly immune senescence on vaccine efficacy, we compared immune responses after virus-like particle (VLP) immunization of elderly cotton rats and young cotton rats, both previously RSV infected, in order to mimic the human population. We show that immunization of RSV-experienced young or elderly animals resulted in the same levels of anti-pre-F IgG, anti-G IgG, neutralizing antibody titers, and protection from challenge indicating that the delivery of F and G proteins in a VLP is equally effective in activation of protective responses in both elderly and young populations. Our results suggest that F and G protein-containing VLPs induce anti-RSV memory established in prior RSV infections equally well in both young and elderly animals and thus can be an effective vaccine for the elderly.
Assuntos
Infecções por Vírus Respiratório Sincicial , Vacinas contra Vírus Sincicial Respiratório , Vírus Sincicial Respiratório Humano , Humanos , Animais , Idoso , Camundongos , Anticorpos Antivirais , Anticorpos Neutralizantes , Proteínas Virais de Fusão , Infecções por Vírus Respiratório Sincicial/prevenção & controle , Sigmodontinae , Imunoglobulina G , Camundongos Endogâmicos BALB CRESUMO
Heterogeneity of COVID-19 manifestations in human population is vast, for reasons unknown. Cotton rats are a clinically relevant small animal model of human respiratory viral infections. Here, we demonstrate for the first time that SARS-CoV-2 infection in cotton rats affects multiple organs and systems, targeting species- and age-specific biological processes. Infection of S. fulviventer, which developed a neutralizing antibody response and were more susceptible to SARS-CoV-2 replication in the upper respiratory tract, was accompanied by hyperplasia of lacrimal drainage-associated lymphoid tissue (LDALT), a first known report of mucosa-associated lymphoid tissue activation at the portal of SARS-CoV-2 entry. Although less permissive to viral replication, S. hispidus showed hyperplasia of bone marrow in the facial bones and increased pulmonary thrombosis in aged males. Augmentation of these features by SARS-CoV-2 infection suggests a virus-induced breach in regulatory mechanisms which could be devastating for people of all ages with underlying conditions and in particular for elderly with a multitude of ongoing disorders.
Assuntos
COVID-19 , Masculino , Animais , Humanos , Idoso , Sigmodontinae , Hiperplasia , SARS-CoV-2 , Fatores EtáriosRESUMO
Although HSV-1 has been implicated in facial palsy for a long time, testing and treating for HSV is not routine. The lack of a meaningful demonstration of how HSV-1 would cause facial palsy has limited progress in this field. Herein we demonstrate that the depth of the lip HSV-1 infection defines the course of the disease, with deeper subcutaneous infection allowing virus access to the facial nerve and causing facial palsy. HSV-1 inoculated subcutaneously caused extensive facial paralysis in cotton rats Sigmodon hispidus, while virus inoculated in the same area of the lip by skin surface abrasion did not. Demyelination along the facial nerve (CN VII) accompanied subcutaneous HSV-1 infection and was identified as the possible underlying mechanism of the disease. This causality demonstration is particularly important in light of increased facial palsy outbreaks associated with SARS-CoV-2 infection and SARS-CoV-2 and influenza vaccinations.
RESUMO
Maternal anti-respiratory syncytial virus (RSV) antibodies protect neonates from RSV disease throughout first weeks of life. Previous studies of maternal immunization in cotton rats showed that a single immunization during pregnancy of RSV-primed dams with virus-like particles (VLPs) assembled with pre-fusion F protein and the wild type G protein boosted their RSV serum antibody concentration and protected pups early in life against RSV challenge. We extended these findings by evaluating responses to RSV infection in litters from two consecutive pregnancies of immunized dams. Using an RSV-primed population of VLP-vaccinated and unvaccinated dams, we defined correlations between dams' and litters' RSV neutralizing antibodies (NA); between litters' NA and protection; and between litter's NA and their lung expression of selected cytokines, of a first or of a second pregnancy. Lung pathology was also evaluated. We found positive correlation between the NA titers in the dams at delivery and the NA in their first and second litters and negative correlations between the litters' NA and protection from RSV challenge. Vaccination of dams modulated the mRNA expression for IFNγ and IL-6 and lung pathology in the first and in the second litter at different times after birth, even in the absence of detectable NA. Maternal RSV vaccination enhanced the levels of antibodies transferred to offspring and their protection from challenge. Importantly, maternal vaccination also impacted the immunological and inflammatory response of the offspring's lungs well into maturity, and after the antiviral effect of maternally transferred NA waned or was no longer detectable.
Assuntos
Infecções por Vírus Respiratório Sincicial , Vacinas contra Vírus Sincicial Respiratório , Vírus Sincicial Respiratório Humano , Animais , Gravidez , Feminino , Sigmodontinae , Imunização , Vacinação , Infecções por Vírus Respiratório Sincicial/prevenção & controle , Pulmão/patologia , Anticorpos Antivirais , Anticorpos Neutralizantes , Proteínas Virais de FusãoRESUMO
Many respiratory viruses cause lung damage that may evolve into acute lung injury (ALI), a cytokine storm, acute respiratory distress syndrome, and ultimately, death. Peroxisome proliferator activated receptor gamma (PPARγ), a member of the nuclear hormone receptor (NHR) family of transcription factors, regulates transcription by forming heterodimers with another NHR family member, Retinoid X Receptor (RXR). Each component of the heterodimer binds specific ligands that modify transcriptional capacity of the entire heterodimer by recruiting different co-activators/co-repressors. However, the role of PPARγ/RXR ligands in the context of influenza infection is not well understood. PPARγ is associated with macrophage differentiation to an anti-inflammatory M2 state. We show that mice lacking the IL-4Rα receptor, required for M2a macrophage differentiation, are more susceptible to mouse-adapted influenza (A/PR/8/34; "PR8")-induced lethality. Mice lacking Ptgs2, that encodes COX-2, a key proinflammatory M1 macrophage mediator, are more resistant. Blocking the receptor for COX-2-induced Prostaglandin E2 (PGE2) was also protective. Treatment with pioglitazone (PGZ), a PPARγ ligand, increased survival from PR8 infection, decreased M1 macrophage gene expression, and increased PPARγ mRNA in lungs. Conversely, conditional knockout mice expressing PPARγ-deficient macrophages were significantly more sensitive to PR8-induced lethality. These findings were extended in cotton rats: PGZ blunted lung inflammation and M1 cytokine gene expression after challenge with non-adapted human influenza. To study mechanisms by which PPARγ/RXR transcription factors induce canonical M2a genes, WT mouse macrophages were treated with IL-4 in the absence or presence of rosiglitazone (RGZ; PPARγ ligand), LG100754 (LG; RXR ligand), or both. IL-4 dose-dependently induced M2a genes Arg1, Mrc1, Chil3, and Retnla. Treatment of macrophages with IL-4 and RGZ and/or LG differentially affected induction of Arg1 and Mrc1 vs. Chil3 and Retnla gene expression. In PPARγ-deficient macrophages, IL-4 alone failed to induce Arg1 and Mrc1 gene expression; however, concurrent treatment with LG or RGZ + LG enhanced IL-4-induced Arg1 and Mrc1 expression, but to a lower level than in WT macrophages, findings confirmed in the murine alveolar macrophage cell line, MH-S. These findings support a model in which PPARγ/RXR heterodimers control IL-4-induced M2a differentiation, and suggest that PPARγ/RXR agonists should be considered as important tools for clinical intervention against influenza-induced ALI.
Assuntos
Lesão Pulmonar Aguda , Influenza Humana , Lesão Pulmonar Aguda/etiologia , Lesão Pulmonar Aguda/metabolismo , Animais , Ciclo-Oxigenase 2/metabolismo , Humanos , Influenza Humana/metabolismo , Interleucina-4/metabolismo , Ligantes , Macrófagos/metabolismo , Camundongos , PPAR gama/metabolismo , Receptores X de Retinoides/metabolismoRESUMO
Dedication: This article is dedicated to Howard Young, an exceptional scientist who has provided outstanding mentorship to many postbaccalaureates, graduate students, and postdoctoral fellows during his career. Howard has been a colleague to many and was never tired of learning new things. He has brought "thinking out of the box" to the level of an art form and has always provided thoughtful and constructive suggestions to those who have sought his counsel. I am personally greatly indebted to Howard for his guidance in molecular biology over the past 30 years, and hope that we will continue to share a passion for learning and mentoring others for years to come. Thank you, Howard! -Stephanie N. Vogel The SARS-CoV-2 pandemic has led to an unprecedented explosion in studies that have sought to identify key mechanisms that underlie the ravaging aspects of this disease on individuals. SARS-CoV-2 virus gains access to cells by (1) binding of the viral spike (S) protein to cell-associated angiotensin-converting enzyme 2 (ACE2), a key receptor in the renin-angiotensin system (RAS), followed by (2) cleavage of S protein by a cellular serine protease ("S protein priming") to facilitate viral entry. Dysregulation of the RAS system has been implicated in the spectrum of clinical symptoms associated with SARS-CoV-2, including hypercytokinemia, elevated markers of endothelial injury and thrombosis, and both localized and systemic inflammation. However, the underlying mechanisms have yet to be fully delineated.
Assuntos
Lesão Pulmonar Aguda , COVID-19 , Masculino , Humanos , Sistema Renina-Angiotensina/fisiologia , SARS-CoV-2/metabolismo , Receptor 4 Toll-Like/metabolismo , Peptidil Dipeptidase A/metabolismo , Transdução de SinaisRESUMO
The cotton rat (Sigmodon) is the gold standard pre-clinical small animal model for respiratory viral pathogens, especially for respiratory syncytial virus (RSV). However, without a reference genome or a published transcriptome, studies requiring gene expression analysis in cotton rats are severely limited. The aims of this study were to generate a comprehensive transcriptome from multiple tissues of two species of cotton rats that are commonly used as animal models (Sigmodon fulviventer and Sigmodon hispidus), and to compare and contrast gene expression changes and immune responses to RSV infection between the two species. Transcriptomes were assembled from lung, spleen, kidney, heart, and intestines for each species with a contig N50 > 1600. Annotation of contigs generated nearly 120,000 gene annotations for each species. The transcriptomes of S. fulviventer and S. hispidus were then used to assess immune response to RSV infection. We identified 238 unique genes that are significantly differentially expressed, including several genes implicated in RSV infection (e.g., Mx2, I27L2, LY6E, Viperin, Keratin 6A, ISG15, CXCL10, CXCL11, IRF9) as well as novel genes that have not previously described in RSV research (LG3BP, SYWC, ABEC1, IIGP1, CREB1). This study presents two comprehensive transcriptome references as resources for future gene expression analysis studies in the cotton rat model, as well as provides gene sequences for mechanistic characterization of molecular pathways. Overall, our results provide generalizable insights into the effect of host genetics on host-virus interactions, as well as identify new host therapeutic targets for RSV treatment and prevention.
Assuntos
Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Animais , Anticorpos Antivirais , Modelos Animais de Doenças , Queratina-6/genética , Pulmão , Vírus Sincicial Respiratório Humano/genética , Sigmodontinae , TranscriptomaRESUMO
Inactivated influenza vaccines are known to be less immunogenic in human elderly in regards to serologic antibody response induced by vaccination. Accumulating evidence, however, points to a comparable effectiveness of influenza vaccines in the young and the elderly individuals. In the current study, we assessed immunogenicity and effectiveness of trivalent inactivated vaccine FluLaval in young and aged cotton rats Sigmodon hispidus and found that while serologic response to immunization was indeed reduced in older animals, comparable protection against influenza infection was afforded by prime-boost vaccination in both young and aged cotton rats. Both hemagglutination inhibition (HAI) titers and seroconversion rates were lower in the aged animals compared to the young ones. Reduction of viral load in the lung and nose, however, was comparable between young and aged animals vaccinated twice. One-time immunization with FluLaval was less efficacious at protecting the nose of aged animals, indicating that boosting of preexisting immunity can be particularly important for nasal protection in the elderly. Coincidentally, a one-time immunization with FluLaval had a detrimental effect on pulmonary pathology in the young animals, suggesting that boosting of immunity is essential for the young as well. Overall, these results suggest that reduced antibody response to and sufficient efficacy of influenza vaccines in the elderly are not two irreconcilable phenomena and that incomplete immunity to influenza can be detrimental at any age.
Assuntos
Vacinas contra Influenza , Influenza Humana , Envelhecimento , Animais , Anticorpos Antivirais , Testes de Inibição da Hemaglutinação , Sigmodontinae , Vacinas de Produtos InativadosRESUMO
BACKGROUND: The cotton rat (genus Sigmodon) is an essential small animal model for the study of human infectious disease and viral therapeutic development. However, the impact of the host microbiome on infection outcomes has not been explored in this model, partly due to the lack of a comprehensive characterization of microbial communities across different cotton rat species. Understanding the dynamics of their microbiome could significantly help to better understand its role when modeling viral infections in this animal model. RESULTS: We examined the bacterial communities of the gut and three external sites (skin, ear, and nose) of two inbred species of cotton rats commonly used in research (S. hispidus and S. fulviventer) by using 16S rRNA gene sequencing, constituting the first comprehensive characterization of the cotton rat microbiome. We showed that S. fulviventer maintained higher alpha diversity and richness than S. hispidus at external sites (skin, ear, nose), but there were no differentially abundant genera. However, S. fulviventer and S. hispidus had distinct fecal microbiomes composed of several significantly differentially abundant genera. Whole metagenomic shotgun sequencing of fecal samples identified species-level differences between S. hispidus and S. fulviventer, as well as different metabolic pathway functions as a result of differential host microbiome contributions. Furthermore, the microbiome composition of the external sites showed significant sex-based differences while fecal communities were not largely different. CONCLUSIONS: Our study shows that host genetic background potentially exerts homeostatic pressures, resulting in distinct microbiomes for two different inbred cotton rat species. Because of the numerous studies that have uncovered strong relationships between host microbiome, viral infection outcomes, and immune responses, our findings represent a strong contribution for understanding the impact of different microbial communities on viral pathogenesis. Furthermore, we provide novel cotton rat microbiome data as a springboard to uncover the full therapeutic potential of the microbiome against viral infections.
RESUMO
BACKGROUND: Infectivity of retroviruses such as HIV-1 and MuLV can be abrogated by compounds targeting zinc finger motif in viral nucleocapsid protein (NC), involved in controlling the processivity of reverse transcription and virus infectivity. Although a member of a different viral family (Pneumoviridae), respiratory syncytial virus (RSV) contains a zinc finger protein M2-1 also involved in control of viral polymerase processivity. Given the functional similarity between the two proteins, it was possible that zinc finger-reactive compounds inactivating retroviruses would have a similar effect against RSV by targeting RSV M2-1 protein. Moreover, inactivation of RSV through modification of an internal protein could yield a safer whole virus vaccine than that produced by RSV inactivation with formalin which modifies surface proteins. RESULTS: Three compounds were evaluated for their ability to reduce RSV infectivity: 2,2'-dithiodipyridine (AT-2), tetraethylthiuram disulfide and tetramethylthiuram disulfide. All three were capable of inactivating RSV, with AT-2 being the most potent. The mechanism of action of AT-2 was analyzed and it was found that AT-2 treatment indeed results in the modification of RSV M2-1. Altered intramolecular disulfide bond formation in M2-1 protein of AT-2-treated RSV virions might have been responsible for abrogation of RSV infectivity. AT-2-inactivated RSV was found to be moderately immunogenic in the cotton rats S.hispidus and did not cause a vaccine-enhancement seen in animals vaccinated with formalin-inactivated RSV. Increasing immunogenicity of AT-2-inactivated RSV by adjuvant (Ribi), however, led to vaccine-enhanced disease. CONCLUSIONS: This work presents evidence that compounds that inactivate retroviruses by targeting the zinc finger motif in their nucleocapsid proteins are also effective against RSV. AT-2-inactivated RSV vaccine is not strongly immunogenic in the absence of adjuvants. In the adjuvanted form, however, vaccine induces immunopathologic response. The mere preservation of surface antigens of RSV, therefore may not be sufficient to produce a highly-efficacious inactivated virus vaccine that does not lead to an atypical disease.
Assuntos
Antivirais/farmacologia , Vírus Sinciciais Respiratórios/efeitos dos fármacos , Proteínas Virais/antagonistas & inibidores , Replicação Viral/efeitos dos fármacos , Dedos de Zinco , 2,2'-Dipiridil/análogos & derivados , 2,2'-Dipiridil/metabolismo , 2,2'-Dipiridil/farmacologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Antivirais/metabolismo , Esqueleto da Parede Celular/administração & dosagem , Fatores Corda/administração & dosagem , Dissulfetos/metabolismo , Dissulfetos/farmacologia , Dissulfiram/metabolismo , Dissulfiram/farmacologia , Lipídeo A/administração & dosagem , Lipídeo A/análogos & derivados , Ligação Proteica , Ratos , Vacinas contra Vírus Sincicial Respiratório/imunologia , Vírus Sinciciais Respiratórios/imunologia , Vírus Sinciciais Respiratórios/fisiologia , Sigmodontinae/virologia , Tiram/metabolismo , Tiram/farmacologia , Vacinas Atenuadas/imunologia , Proteínas Virais/metabolismoRESUMO
Respiratory Syncytial Virus (RSV) is the leading cause of pneumonia and bronchiolitis in infants and children <1 year old, resulting in significant morbidity and mortality worldwide. There is currently no RSV vaccine. In the 1960s, a formalin-inactivated RSV (FI-RSV) vaccine trial led to exacerbated disease upon natural infection of vaccinees, including two deaths. The causes involved in the disastrous results of these vaccine trials are still unclear but they remain the engine for searching new avenues to develop a safe vaccine that can provide long-term protection against this important pathogen. This article reviews some of the early history of RSV vaccine development,as well as more recent information on the interaction between RSV and the host innate and adaptive immune responses. A safe and efficacious vaccine for RSV will require "re-education" of the host immune response against RSV to prevent vaccine-enhanced or severe RSV disease.