RESUMO
The 2013-2015 West African epidemic of Ebola virus disease (EVD) reminds us of how little is known about biosafety level 4 viruses. Like Ebola virus, Lassa virus (LASV) can cause hemorrhagic fever with high case fatality rates. We generated a genomic catalog of almost 200 LASV sequences from clinical and rodent reservoir samples. We show that whereas the 2013-2015 EVD epidemic is fueled by human-to-human transmissions, LASV infections mainly result from reservoir-to-human infections. We elucidated the spread of LASV across West Africa and show that this migration was accompanied by changes in LASV genome abundance, fatality rates, codon adaptation, and translational efficiency. By investigating intrahost evolution, we found that mutations accumulate in epitopes of viral surface proteins, suggesting selection for immune escape. This catalog will serve as a foundation for the development of vaccines and diagnostics. VIDEO ABSTRACT.
Assuntos
Genoma Viral , Febre Lassa/virologia , Vírus Lassa/genética , RNA Viral/genética , África Ocidental/epidemiologia , Animais , Evolução Biológica , Reservatórios de Doenças , Ebolavirus/genética , Variação Genética , Glicoproteínas/genética , Doença pelo Vírus Ebola/virologia , Humanos , Febre Lassa/epidemiologia , Febre Lassa/transmissão , Vírus Lassa/classificação , Vírus Lassa/fisiologia , Murinae/genética , Mutação , Nigéria/epidemiologia , Proteínas Virais/genética , Zoonoses/epidemiologia , Zoonoses/virologiaRESUMO
Hyperlipidemia and hypertension are modifiable risk factors for cognitive decline. About 25% of adults over age 65 use both antihypertensives (AHTs) and statins to treat these conditions. Recent research in humans suggests that their combined use may delay or prevent dementia onset. However, it is not clear whether and how combination treatment may benefit brain function. To begin to address this question, we examined effects of atorvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, and Captopril, an angiotensin-converting enzyme inhibitor (ACEI), administration on memory function, anxiety-like behavior, adult hippocampal neurogenesis and angiogenesis in adult and middle-aged male C57Bl/6J mice. In adult mice (3-months-old) combination (combo) treatment, as well as administration of each compound individually, for six weeks, accelerated memory extinction in contextual fear conditioning. However, pattern separation in the touchscreen-based location discrimination test, a behavior linked to adult hippocampal neurogenesis, was unchanged. In addition, dentate gyrus (DG) neurogenesis and vascularization were unaffected. In middle-aged mice (10-months-old) combo treatment had no effect on spatial memory in the Morris water maze, but did reduce anxiety in the open field test. A potential underlying mechanism may be the modest increase in new hippocampal neurons (~20%) in the combo as compared to the control group. DG vascularization was not altered. Overall, our findings suggest that statin and anti-hypertensive treatment may serve as a potential pharmacotherapeutic approach for anxiety, in particular for post-traumatic stress disorder (PTSD) patients who have impairments in extinction of aversive memories.
Assuntos
Fatores Etários , Anti-Hipertensivos/farmacologia , Medo/efeitos dos fármacos , Memória/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Animais , Extinção Psicológica/efeitos dos fármacos , Medo/fisiologia , Hipocampo/efeitos dos fármacos , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Masculino , Camundongos Endogâmicos C57BL , Neurogênese/fisiologia , Neurônios/fisiologiaRESUMO
Increasing evidence indicates that physical activity and exercise training may delay or prevent the onset of Alzheimer's disease (AD). However, systemic biomarkers that can measure exercise effects on brain function and that link to relevant metabolic responses are lacking. To begin to address this issue, we utilized blood samples of 23 asymptomatic late middle-aged adults, with familial and genetic risk for AD (mean age 65 years old, 50% female) who underwent 26 weeks of supervised treadmill training. Systemic biomarkers implicated in learning and memory, including the myokine Cathepsin B (CTSB), brain-derived neurotrophic factor (BDNF), and klotho, as well as metabolomics were evaluated. Here we show that aerobic exercise training increases plasma CTSB and that changes in CTSB, but not BDNF or klotho, correlate with cognitive performance. BDNF levels decreased with exercise training. Klotho levels were unchanged by training, but closely associated with change in VO2peak. Metabolomic analysis revealed increased levels of polyunsaturated free fatty acids (PUFAs), reductions in ceramides, sphingo- and phospholipids, as well as changes in gut microbiome metabolites and redox homeostasis, with exercise. Multiple metabolites (~30%) correlated with changes in BDNF, but not CSTB or klotho. The positive association between CTSB and cognition, and the modulation of lipid metabolites implicated in dementia, support the beneficial effects of exercise training on brain function. Overall, our analyses indicate metabolic regulation of exercise-induced plasma BDNF changes and provide evidence that CTSB is a marker of cognitive changes in late middle-aged adults at risk for dementia.
Assuntos
Doença de Alzheimer , Fator Neurotrófico Derivado do Encéfalo/sangue , Catepsina B/sangue , Cognição , Exercício Físico , Proteínas Klotho/sangue , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Ácidos Graxos Ômega-3/sangue , Feminino , Microbioma Gastrointestinal , Humanos , Hidroxiprolina/sangue , Metabolismo dos Lipídeos , Masculino , Metabolômica , Pessoa de Meia-Idade , Prolina/análogos & derivados , Prolina/sangue , Fatores de RiscoRESUMO
While investigating a signal of adaptive evolution in humans at the gene LARGE, we encountered an intriguing finding by Dr. Stefan Kunz that the gene plays a critical role in Lassa virus binding and entry. This led us to pursue field work to test our hypothesis that natural selection acting on LARGE-detected in the Yoruba population of Nigeria-conferred resistance to Lassa Fever in some West African populations. As we delved further, we conjectured that the "emerging" nature of recently discovered diseases like Lassa fever is related to a newfound capacity for detection, rather than a novel viral presence, and that humans have in fact been exposed to the viruses that cause such diseases for much longer than previously suspected. Dr. Stefan Kunz's critical efforts not only laid the groundwork for this discovery, but also inspired and catalyzed a series of events that birthed Sentinel, an ambitious and large-scale pandemic prevention effort in West Africa. Sentinel aims to detect and characterize deadly pathogens before they spread across the globe, through implementation of its three fundamental pillars: Detect, Connect, and Empower. More specifically, Sentinel is designed to detect known and novel infections rapidly, connect and share information in real time to identify emerging threats, and empower the public health community to improve pandemic preparedness and response anywhere in the world. We are proud to dedicate this work to Stefan Kunz, and eagerly invite new collaborators, experts, and others to join us in our efforts.
Assuntos
Planejamento em Desastres , Febre Lassa/epidemiologia , Vírus Lassa/fisiologia , África Ocidental/epidemiologia , Planejamento em Desastres/métodos , Humanos , Febre Lassa/genética , Febre Lassa/prevenção & controle , Febre Lassa/virologia , Vírus Lassa/genética , N-Acetilglucosaminiltransferases/genética , N-Acetilglucosaminiltransferases/imunologia , Nigéria/epidemiologia , Pandemias , Polimorfismo Genético , Receptores Virais/genética , Receptores Virais/imunologiaRESUMO
Host cell barriers to the early phase of immunodeficiency virus replication explain the current distribution of these viruses among human and non-human primate species. Human immunodeficiency virus type 1 (HIV-1), the cause of acquired immunodeficiency syndrome (AIDS) in humans, efficiently enters the cells of Old World monkeys but encounters a block before reverse transcription. This species-specific restriction acts on the incoming HIV-1 capsid and is mediated by a dominant repressive factor. Here we identify TRIM5alpha, a component of cytoplasmic bodies, as the blocking factor. HIV-1 infection is restricted more efficiently by rhesus monkey TRIM5alpha than by human TRIM5alpha. The simian immunodeficiency virus, which naturally infects Old World monkeys, is less susceptible to the TRIM5alpha-mediated block than is HIV-1, and this difference in susceptibility is due to the viral capsid. The early block to HIV-1 infection in monkey cells is relieved by interference with TRIM5alpha expression. Our studies identify TRIM5alpha as a species-specific mediator of innate cellular resistance to HIV-1 and reveal host cell components that modulate the uncoating of a retroviral capsid.
Assuntos
Estruturas Citoplasmáticas/química , Suscetibilidade a Doenças , Infecções por HIV/metabolismo , HIV-1/fisiologia , Macaca mulatta/metabolismo , Macaca mulatta/virologia , Proteínas/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular , Clonagem Molecular , Estruturas Citoplasmáticas/metabolismo , Variação Genética/genética , Infecções por HIV/veterinária , Infecções por HIV/virologia , HIV-1/genética , Células HeLa , Humanos , Macaca mulatta/genética , Dados de Sequência Molecular , Mutação/genética , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas/química , Proteínas/genética , Vírus da Imunodeficiência Símia/fisiologia , Especificidade da Espécie , Ubiquitina-Proteína Ligases , Replicação ViralRESUMO
Rhabdoviruses are a large and ecologically diverse family of negative-sense RNA viruses (Mononegavirales: Rhabdoviridae). These viruses are capable of infecting an unexpectedly wide variety of plants, vertebrates, and invertebrates distributed over all human-inhabited continents. However, only a few rhabdoviruses are known to infect humans: a ledantevirus (Le Dantec virus), several lyssaviruses (in particular, rabies virus), and several vesiculoviruses (e.g., Chandipura virus, vesicular stomatitis Indiana virus). Recently, several novel rhabdoviruses have been discovered in the blood of both healthy and severely ill individuals living in Central and Western Africa. These viruses-Bas-Congo virus, Ekpoma virus 1, and Ekpoma virus 2-are members of the little-understood rhabdoviral genus Tibrovirus. Other than the basic genomic architecture, tibroviruses bear little resemblance to well-studied rhabdoviruses such as rabies virus and vesicular stomatitis Indiana virus. These three human tibroviruses are quite divergent from each other, and each of them clusters closely with tibroviruses currently known only from biting midges or healthy cattle. Seroprevalence studies suggest that human tibrovirus infections may be common but are almost entirely unrecognized. The pathogenic potential of this diverse group of viruses remains unknown. Although certain tibroviruses may be benign and well-adapted to humans, others could be newly emerging and produce serious disease. Here, we review the current knowledge of tibroviruses and argue that assessing their impact on human health should be an urgent priority.
Assuntos
Interações Hospedeiro-Patógeno , Infecções por Rhabdoviridae/etiologia , Rhabdoviridae/fisiologia , Simbiose , África/epidemiologia , Animais , Produtos Biológicos , Efeito Citopatogênico Viral , Exposição Ambiental , Variação Genética , Genoma Viral , Genômica/métodos , Humanos , Vigilância em Saúde Pública , Rhabdoviridae/classificação , Rhabdoviridae/patogenicidade , Rhabdoviridae/ultraestrutura , Infecções por Rhabdoviridae/epidemiologia , Infecções por Rhabdoviridae/transmissão , Tropismo Viral , Internalização do Vírus , Replicação ViralRESUMO
Rhesus TRIM5alpha (rhTRIM5alpha), but not human TRIM5alpha (huTRIM5alpha), potently inhibits human immunodeficiency virus (HIV) infection and is thus a potentially valuable therapeutic tool. Primary human CD4 T cells engineered to express rhTRIM5alpha were highly resistant to cell-free HIV type 1 (HIV-1) infection. However, when cocultured with unmodified T cells, rhTRIM5alpha-expressing cells became highly permissive to HIV-1 infection. Physical separation of rhTRIM5alpha-expressing cells and unmodified cells revealed that rhTRIM5alpha efficiently restricts cell-free but not cell-associated HIV transmission. Furthermore, we observed that HIV-infected human cells could infect rhesus CD4 T cells by cell-to-cell contact, but the infection was self-limiting. Subsequently, we noted that a spreading infection ensued when HIV-1-infected rhTRIM5alpha-expressing human cells were cultured with huTRIM5alpha- but not rhTRIM5alpha-expressing cells. Our results suggest that cell-associated HIV transmission in humans is blocked only when both donor and recipient cells express rhTRIM5alpha. These studies further define the role of rhTRIM5alpha in cell-free and cell-associated HIV transmission and delineate the utility of rhTRIM5alpha in anti-HIV therapy.
Assuntos
HIV-1/imunologia , Imunidade Inata , Proteínas/imunologia , Animais , Linfócitos T CD4-Positivos/virologia , Células Cultivadas , Técnicas de Cocultura , HIV-1/crescimento & desenvolvimento , Humanos , Macaca mulatta , Ubiquitina-Proteína LigasesRESUMO
Exercise has profound benefits for brain function in animals and humans. In rodents, voluntary wheel running increases the production of new neurons and upregulates neurotrophin levels in the hippocampus, as well as improving synaptic plasticity, memory function and mood. The underlying cellular mechanisms, however, remain unresolved. Recent research indicates that peripheral organs such as skeletal muscle, liver and adipose tissue secrete factors during physical activity that may influence neuronal function. Here we used an in vitro cell assay and proteomic analysis to investigate the effects of proteins secreted from skeletal muscle cells on adult hippocampal neural progenitor cell (aNPC) differentiation. We also sought to identify the relevant molecules driving these effects. Specifically, we treated rat L6 skeletal muscle cells with the AMP-kinase (AMPK) agonist 5-aminoimidazole-4-carboxamide-1-ß-d-ribofuranoside (AICAR) or vehicle (distilled water). We then collected the conditioned media (CM) and fractionated it using high-performance liquid chromatography (HPLC). Treatment of aNPCs with a specific fraction of the AICAR-CM upregulated expression of doublecortin (DCX) and Tuj1, markers of immature neurons. Proteomic analysis of this fraction identified proteins known to be involved in energy metabolism, cell migration, adhesion and neurogenesis. Culturing differentiating aNPCs in the presence of one of the factors, glycolytic enzyme glucose-6-phosphate isomerase (GPI), or AICAR-CM, increased the proportion of neuronal (Tuj1+) and astrocytic, glial fibrillary acidic protein (GFAP+) cells. Our study provides further evidence that proteins secreted from skeletal muscle cells may serve as a critical communication link to the brain through factors that enhance neural differentiation.
Assuntos
Aminoimidazol Carboxamida/análogos & derivados , Fármacos do Sistema Nervoso Central/farmacologia , Meios de Cultivo Condicionados/farmacologia , Fibras Musculares Esqueléticas/metabolismo , Células-Tronco Neurais/efeitos dos fármacos , Ribonucleotídeos/farmacologia , Adenilato Quinase/metabolismo , Aminoimidazol Carboxamida/farmacologia , Animais , Células Cultivadas , Giro Denteado/efeitos dos fármacos , Giro Denteado/fisiologia , Proteína Duplacortina , Masculino , Camundongos Endogâmicos C57BL , Atividade Motora/fisiologia , Fibras Musculares Esqueléticas/efeitos dos fármacos , Células-Tronco Neurais/fisiologia , Neurogênese/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Proteoma , RatosRESUMO
Next-generation sequencing (NGS) has the potential to transform the discovery of viruses causing unexplained acute febrile illness (UAFI) because it does not depend on culturing the pathogen or a priori knowledge of the pathogen's nucleic acid sequence. More generally, it has the potential to elucidate the complete human virome, including viruses that cause no overt symptoms of disease, but may have unrecognized immunological or developmental consequences. We have used NGS to identify RNA viruses in the blood of 195 patients with UAFI and compared them with those found in 328 apparently healthy (i.e., no overt signs of illness) control individuals, all from communities in southeastern Nigeria. Among UAFI patients, we identified the presence of nucleic acids from several well-characterized pathogenic viruses, such as HIV-1, hepatitis, and Lassa virus. In our cohort of healthy individuals, however, we detected the nucleic acids of two novel rhabdoviruses. These viruses, which we call Ekpoma virus-1 (EKV-1) and Ekpoma virus-2 (EKV-2), are highly divergent, with little identity to each other or other known viruses. The most closely related rhabdoviruses are members of the genus Tibrovirus and Bas-Congo virus (BASV), which was recently identified in an individual with symptoms resembling hemorrhagic fever. Furthermore, by conducting a serosurvey of our study cohort, we find evidence for remarkably high exposure rates to the identified rhabdoviruses. The recent discoveries of novel rhabdoviruses by multiple research groups suggest that human infection with rhabdoviruses might be common. While the prevalence and clinical significance of these viruses are currently unknown, these viruses could have previously unrecognized impacts on human health; further research to understand the immunological and developmental impact of these viruses should be explored. More generally, the identification of similar novel viruses in individuals with and without overt symptoms of disease highlights the need for a broader understanding of the human virome as efforts for viral detection and discovery advance.
Assuntos
RNA Viral/genética , Infecções por Rhabdoviridae/diagnóstico , Infecções por Rhabdoviridae/virologia , Rhabdoviridae/isolamento & purificação , Adulto , África Ocidental/epidemiologia , Sequência de Bases , Estudos de Casos e Controles , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Nigéria/epidemiologia , Vírus de RNA/classificação , Vírus de RNA/genética , Vírus de RNA/isolamento & purificação , Rhabdoviridae/classificação , Rhabdoviridae/genética , Infecções por Rhabdoviridae/epidemiologia , Análise de Sequência de RNARESUMO
We have developed a robust RNA sequencing method for generating complete de novo assemblies with intra-host variant calls of Lassa and Ebola virus genomes in clinical and biological samples. Our method uses targeted RNase H-based digestion to remove contaminating poly(rA) carrier and ribosomal RNA. This depletion step improves both the quality of data and quantity of informative reads in unbiased total RNA sequencing libraries. We have also developed a hybrid-selection protocol to further enrich the viral content of sequencing libraries. These protocols have enabled rapid deep sequencing of both Lassa and Ebola virus and are broadly applicable to other viral genomics studies.
Assuntos
Ebolavirus/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Vírus Lassa/genética , Doença pelo Vírus Ebola/genética , Doença pelo Vírus Ebola/virologia , Humanos , Febre Lassa/genética , Febre Lassa/virologia , RNA ViralRESUMO
The cross-species transmission of retroviruses is limited by host restriction factors that exhibit inter-species diversity. For example, the TRIM5α proteins of Old World monkeys block the early, post-entry steps in human immunodeficiency virus (HIV-1) infection. We adapted an HIV-1 isolate to replicate in cells expressing TRIM5α(rh) from rhesus monkeys, an Old World species. A single amino acid change in the cyclophilin-binding loop of the HIV-1 capsid protein allowed virus replication in cells expressing TRIM5α(rh). The capsid of the escape virus exhibited a reduced affinity for TRIM5α(rh), but retained the ability to bind cyclophilin A efficiently. Thus, a preferred HIV-1 escape pathway involves decreased binding to TRIM5α, a capsid-destabilizing factor, and retention of binding to cyclophilin A, a capsid-stabilizing factor.
Assuntos
Adaptação Fisiológica , HIV-1/fisiologia , HIV-1/patogenicidade , Proteínas/fisiologia , Adaptação Fisiológica/genética , Animais , Proteínas do Capsídeo/metabolismo , Ciclofilina A/metabolismo , HIV-1/genética , Células HeLa , Humanos , Macaca mulatta , Modelos Moleculares , Complexos Multiproteicos , Mutação , Proteínas/química , Proteínas/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Especificidade da Espécie , Ubiquitina-Proteína Ligases , Replicação Viral/genética , Replicação Viral/fisiologiaRESUMO
The restriction factors, TRIM5alpha in most primates and TRIMCyp in owl monkeys, block infection of various retroviruses soon after virus entry into the host cell. Rhesus monkey TRIM5alpha (TRIM5alpha rh) inhibits human immunodeficiency virus (HIV-1) and feline immunodeficiency virus (FIV) more potently than human TRIM5alpha (TRIM5alpha hu). TRIMCyp restricts infection of HIV-1, simian immunodeficiency virus of African green monkeys (SIV agm) and FIV. Early after infection, TRIMCyp, like TRIM5alpha rh and TRIM5alpha hu, decreased the amount of particulate viral capsid in the cytosol of infected cells. The requirements for the TRIMCyp and TRIM5alpha domains in restricting different retroviruses were investigated. Potent restriction of FIV by TRIMCyp occurred in the complete absence of RING and B-box 2 domains; by contrast, efficient FIV restriction by TRIM5alpha rh required these domains. Variable region 1 of the TRIM5alpha rh B30.2 domain contributed to the potency of HIV-1, FIV and equine infectious anemia virus restriction. Thus, although differences exist in the requirements of TRIMCyp and TRIM5alpha for RING/B-box 2 domains, both restriction factors exhibit mechanistic similarities.
Assuntos
Proteínas de Transporte/fisiologia , Proteínas/fisiologia , Infecções por Retroviridae/fisiopatologia , Animais , Fatores de Restrição Antivirais , Aotidae , Capsídeo/fisiologia , Proteínas de Transporte/química , Proteínas de Transporte/genética , Gatos , Linhagem Celular , HIV-1/genética , HIV-1/fisiologia , Humanos , Vírus da Imunodeficiência Felina/genética , Vírus da Imunodeficiência Felina/fisiologia , Estrutura Terciária de Proteína , Proteínas/química , Proteínas/genética , Infecções por Retroviridae/virologia , Proteínas com Motivo Tripartido , Ubiquitina-Proteína LigasesRESUMO
The host cell factors TRIM5alpha(hu) and Fv-1 restrict N-tropic murine leukemia virus (N-MLV) infection at an early postentry step before or after reverse transcription, respectively. Interestingly, the identity of residue 110 of the MLV capsid determines susceptibility to both TRIM5alpha(hu) and Fv-1. In this study, we investigate the fate of the MLV capsid in cells expressing either the TRIM5alpha(hu) or Fv-1 restriction factor. The expression of TRIM5alpha(hu), but not Fv-1, specifically promoted the premature conversion of particulate N-MLV capsids within infected cells to soluble capsid proteins. The TRIM5alpha(hu)-mediated disassembly of particulate N-MLV capsids was dependent upon residue 110 of the viral capsid. Furthermore, the deletion or disruption of TRIM5alpha(hu) domains necessary for potent N-MLV restriction completely abrogated the disappearance of particulate N-MLV capsids observed with wild-type TRIM5alpha(hu). These results suggest that premature disassembly of the viral capsid contributes to the restriction of N-MLV infection by TRIM5alpha(hu), but not by Fv-1.
Assuntos
Proteínas de Transporte/fisiologia , Vírus da Leucemia Murina/fisiologia , Substituição de Aminoácidos , Animais , Fatores de Restrição Antivirais , Sequência de Bases , Capsídeo/fisiologia , Proteínas de Transporte/química , Proteínas de Transporte/genética , Linhagem Celular , Primers do DNA/genética , Humanos , Vírus da Leucemia Murina/genética , Vírus da Leucemia Murina/patogenicidade , Camundongos , Mutagênese Sítio-Dirigida , Células NIH 3T3 , Estrutura Terciária de Proteína , Proteínas/genética , Proteínas/fisiologia , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas com Motivo Tripartido , Ubiquitina-Proteína LigasesAssuntos
Doenças Transmissíveis Emergentes/epidemiologia , Doença pelo Vírus Ebola/epidemiologia , Febres Hemorrágicas Virais/epidemiologia , Febre Lassa/epidemiologia , África Subsaariana/epidemiologia , Animais , Anticorpos Antivirais/sangue , Serviços de Saúde Comunitária , Surtos de Doenças , Reservatórios de Doenças , Resistência à Doença/genética , Ebolavirus/genética , Ebolavirus/imunologia , Ebolavirus/patogenicidade , Evolução Molecular , Doença pelo Vírus Ebola/diagnóstico , Doença pelo Vírus Ebola/transmissão , Doença pelo Vírus Ebola/virologia , Febres Hemorrágicas Virais/diagnóstico , Febres Hemorrágicas Virais/imunologia , Febres Hemorrágicas Virais/virologia , Humanos , Febre Lassa/diagnóstico , Febre Lassa/transmissão , Febre Lassa/virologia , Vírus Lassa/genética , Vírus Lassa/imunologia , Vírus Lassa/patogenicidade , Prevalência , Doenças dos Primatas/epidemiologia , Primatas , Estudos SoroepidemiológicosRESUMO
The tripartite motif (TRIM) protein, TRIM5alpha, restricts some retroviruses, including human immunodeficiency virus (HIV-1), from infecting the cells of particular species. TRIM proteins contain RING, B-box, coiled-coil and, in some cases, B30.2(SPRY) domains. We investigated the properties of human TRIM family members closely related to TRIM5. These TRIM proteins, like TRIM5alpha, assembled into homotrimers and co-localized in the cytoplasm with TRIM5alpha. TRIM5alpha turned over more rapidly than related TRIM proteins. TRIM5alpha, TRIM34 and TRIM6 associated with HIV-1 capsid-nucleocapsid complexes assembled in vitro; the TRIM5alpha and TRIM34 interactions with these complexes were dependent on their B30.2(SPRY) domains. Only TRIM5alpha potently restricted infection by the retroviruses studied; overexpression of TRIM34 resulted in modest inhibition of simian immunodeficiency virus (SIV(mac)) infection. In contrast to the other TRIM genes examined, TRIM5 exhibited evidence of positive selection. The unique features of TRIM5alpha among its TRIM relatives underscore its special status as an antiviral factor.
Assuntos
Proteínas de Transporte/metabolismo , HIV-1/fisiologia , Nucleocapsídeo/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Fatores de Restrição Antivirais , Proteínas de Transporte/química , Proteínas de Transporte/genética , Linhagem Celular , Citoplasma/química , Cães , HIV-1/imunologia , Células HeLa , Humanos , Macaca mulatta , Proteínas de Membrana/metabolismo , Filogenia , Ligação Proteica , Proteínas com Motivo Tripartido , Ubiquitina-Proteína LigasesRESUMO
Human TRIM5alpha (TRIM5alpha(hu)) potently restricts N-tropic (N-MLV), but not B-tropic, murine leukemia virus in a manner dependent upon residue 110 of the viral capsid. Rhesus monkey TRIM5alpha (TRIM5alpha(rh)) inhibits N-MLV only weakly. The study of human-monkey TRIM5alpha chimerae revealed that both the v1 and v3 variable regions of the B30.2/SPRY domain contain potency determinants for N-MLV restriction. These variable regions are predicted to be surface-exposed elements on one face of the B30.2 domain. Acidic residues in v3 complement basic residue 110 of the N-MLV capsid. The results support recognition of the retroviral capsid by the TRIM5alpha B30.2 domain.
Assuntos
Antígenos Virais/imunologia , Proteínas de Transporte/genética , Vírus da Leucemia Murina/efeitos dos fármacos , Infecções por Retroviridae/prevenção & controle , Sequência de Aminoácidos , Antígenos Virais/efeitos dos fármacos , Fatores de Restrição Antivirais , Capsídeo/fisiologia , Proteínas de Transporte/química , Proteínas de Transporte/farmacologia , Humanos , Vírus da Leucemia Murina/química , Vírus da Leucemia Murina/patogenicidade , Estrutura Terciária de Proteína , Proteínas/química , Proteínas/farmacologia , Infecções por Retroviridae/fisiopatologia , Proteínas com Motivo Tripartido , Ubiquitina-Proteína LigasesRESUMO
Cyclophilin A (Cyp A) binds the human immunodeficiency virus type 1 (HIV-1) capsid (CA) protein and contributes to the early events in virus replication in some cells. The retroviral restriction factor TRIM5alpha can inhibit the early, post-entry phase of infection by associating with the incoming viral capsid. Cyp A has been proposed to prevent restriction factor binding in human cells, thus enhancing HIV-1 infectivity, and to potentiate restriction of HIV-1 in monkey cells. Here we show that the positive effects of Cyp A-CA binding on HIV-1 infectivity do not depend on human TRIM5alpha. Disruption of Cyp A binding to CA partially relieved the block to HIV-1 infection imposed by several TRIM5alpha variants, but Cyp A-CA binding was not absolutely required for TRIM5alpha antiviral activity. Inhibition of Cyp A function by cyclosporine significantly decreased the efficiency of TRIM5alpha-mediated restriction only when the restricted virus capsid interacted with Cyp A.
Assuntos
Proteínas de Transporte/metabolismo , Ciclofilina A/metabolismo , HIV-1/metabolismo , Animais , Fatores de Restrição Antivirais , Proteínas de Transporte/genética , Linhagem Celular , Ciclosporina/farmacologia , Cães , Inativação Gênica , Haplorrinos , Humanos , Imunossupressores/farmacologia , Ligação Proteica , RNA Interferente Pequeno , Tacrolimo/metabolismo , Proteínas com Motivo Tripartido , Ubiquitina-Proteína Ligases , Replicação ViralRESUMO
Human TRIM5alpha (TRIM5alpha(hu)) only modestly inhibits human immunodeficiency virus type 1 (HIV-1) and does not inhibit simian immunodeficiency virus (SIV(mac)). Alteration of arginine 332 in the TRIM5alpha(hu) B30.2 domain to proline, the residue found in rhesus monkey TRIM5alpha, has been shown to create a potent restricting factor for both HIV-1 and SIV(mac.) Here we demonstrate that the potentiation of HIV-1 inhibition results from the removal of a positively charged residue at position 332 of TRIM5alpha(hu.) The increase in restricting activity correlated with an increase in the ability of TRIM5alpha(hu) mutants lacking arginine 332 to bind HIV-1 capsid complexes. A change in the cyclophilin A-binding loop of the HIV-1 capsid decreased TRIM5alpha(hu) R332P binding and allowed escape from restriction. The ability of TRIM5alpha(hu) to restrict SIV(mac) could be disrupted by the presence of any charged residue at position 332. Thus, charged residues in the v1 region of the TRIM5alpha(hu) B30.2 domain can modulate capsid binding and restriction potency. Therapeutic strategies designed to neutralize arginine 332 of TRIM5alpha(hu) might potentiate the innate resistance of human cells to HIV-1 infection.
Assuntos
Arginina/metabolismo , Capsídeo/metabolismo , Proteínas de Transporte/metabolismo , Infecções por HIV/metabolismo , HIV-1/metabolismo , Mutação Puntual , Fármacos Anti-HIV/uso terapêutico , Fatores de Restrição Antivirais , Arginina/antagonistas & inibidores , Arginina/genética , Proteínas de Transporte/antagonistas & inibidores , Proteínas de Transporte/genética , Ciclofilina A/metabolismo , Desenho de Fármacos , Infecções por HIV/tratamento farmacológico , Infecções por HIV/genética , HIV-1/genética , Células HeLa , Humanos , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/genética , Estrutura Terciária de Proteína , Vírus da Imunodeficiência Símia/genética , Vírus da Imunodeficiência Símia/metabolismo , Especificidade da Espécie , Proteínas com Motivo Tripartido , Ubiquitina-Proteína LigasesRESUMO
TRIM5alpha and TRIMCyp are retroviral restriction factors that, like other members of the tripartite motif (TRIM) family, contain RING, B-box 2 and coiled-coil domains. We found that both proteins are rapidly turned over, with half-lives of 50-60 min. Polyubiquitylation and rapid degradation of TRIM5alpha depended upon intact RING and B-box 2 domains. A chimera consisting of monkey TRIM5alpha with a RING domain of human TRIM21 exhibited a half-life of 210 min, yet potently restricted human immunodeficiency virus; therefore, rapid turnover of TRIM5alpha is not required for its antiretroviral activity. TRIM5alpha forms cytoplasmic bodies that contain other polyubiquitylated proteins, heat shock proteins and dynein, and thus resemble aggresome precursors. Consistent with this interpretation, proteasomal inhibitors triggered the formation of TRIM5alpha(rh)-containing aggresomes in a microtubule-dependent manner. Thus, TRIM5alpha levels in the cell are maintained by continuous synthesis and rapid proteasome-mediated degradation, imbalances in which result in the formation of pre-aggresomal cytoplasmic bodies.
Assuntos
Proteínas de Transporte/metabolismo , Poliubiquitina/metabolismo , Processamento de Proteína Pós-Traducional , Proteínas/metabolismo , Fatores de Restrição Antivirais , Proteínas de Transporte/química , Proteínas de Transporte/genética , Citoplasma/química , Citoplasma/metabolismo , Dineínas/análise , HIV-1/fisiologia , Meia-Vida , Células HeLa , Proteínas de Choque Térmico/análise , Humanos , Imuno-Histoquímica , Corpos de Inclusão/metabolismo , Substâncias Macromoleculares/análise , Microscopia Confocal , Microscopia de Fluorescência , Modelos Biológicos , Nocodazol/farmacologia , Complexo de Endopeptidases do Proteassoma/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma/metabolismo , Estrutura Terciária de Proteína , Proteínas/química , Proteínas/genética , Proteínas com Motivo Tripartido , Ubiquitina-Proteína LigasesRESUMO
Tripartite motif 5alpha (TRIM5alpha) restricts some retroviruses, including human immunodeficiency virus type 1 (HIV-1), from infecting the cells of particular species. TRIM5alpha is a member of the TRIM family of proteins, which contain RING, B-box, coiled-coil (CC), and, in some cases, B30.2(SPRY) domains. Here we investigated the abilities of domains from TRIM proteins (TRIM6, TRIM34, and TRIM21) that do not restrict HIV-1 infection to substitute for the domains of rhesus monkey TRIM5alpha (TRIM5alpha(rh)). The RING, B-box 2, and CC domains of the paralogous TRIM6 and TRIM34 proteins functionally replaced the corresponding TRIM5alpha(rh) domains, allowing HIV-1 restriction. By contrast, similar chimeras containing the components of TRIM21, a slightly more distant relative of TRIM5, did not restrict HIV-1 infection. The TRIM21 B-box 2 domain and its flanking linker regions contributed to the functional defectiveness of these chimeras. All of the chimeric proteins formed trimers. All of the chimeras that restricted HIV-1 infection bound the assembled HIV-1 capsid complexes. These results indicate that heterologous RING, B-box 2, and CC domains from related TRIM proteins can functionally substitute for TRIM5alpha(rh) domains.