RESUMO
BACKGROUND: Coinfection with two phylogenetically distinct Human Immunodeficiency Virus-1 (HIV-1) variants might provide an opportunity for rapid viral expansion and the emergence of fit variants that drive disease progression. However, autologous neutralising immune responses are known to drive Envelope (Env) diversity which can either enhance replicative capacity, have no effect, or reduce viral fitness. This study investigated whether in vivo outgrowth of coinfecting variants was linked to pseudovirus and infectious molecular clones' infectivity to determine whether diversification resulted in more fit virus with the potential to increase disease progression. RESULTS: For most participants, emergent recombinants displaced the co-transmitted variants and comprised the major population at 52 weeks postinfection with significantly higher entry efficiency than other co-circulating viruses. Our findings suggest that recombination within gp41 might have enhanced Env fusogenicity which contributed to the increase in pseudovirus entry efficiency. Finally, there was a significant correlation between pseudovirus entry efficiency and CD4 + T cell count, suggesting that the enhanced replicative capacity of recombinant variants could result in more virulent viruses. CONCLUSION: Coinfection provides variants with the opportunity to undergo rapid recombination that results in more infectious virus. This highlights the importance of monitoring the replicative fitness of emergent viruses.
Assuntos
Coinfecção , Infecções por HIV , HIV-1 , Filogenia , Humanos , Infecções por HIV/virologia , Infecções por HIV/complicações , HIV-1/genética , HIV-1/fisiologia , Coinfecção/virologia , Evolução Molecular , Produtos do Gene env do Vírus da Imunodeficiência Humana/genética , Proteína gp41 do Envelope de HIV/genética , Masculino , Feminino , Recombinação Genética , Internalização do Vírus , Adulto , Contagem de Linfócito CD4 , Replicação ViralRESUMO
The HIV-1 capsid is composed of capsid (CA) protein hexamers and pentamers (capsomers) that contain a central pore hypothesised to regulate capsid assembly and facilitate nucleotide import early during post-infection. These pore functions are mediated by two positively charged rings created by CA Arg-18 (R18) and Lys-25 (K25). Here we describe the forced evolution of viruses containing mutations in R18 and K25. Whilst R18 mutants fail to replicate, K25A viruses acquire compensating mutations that restore nearly wild-type replication fitness. These compensating mutations, which rescue reverse transcription and infection without reintroducing lost pore charges, map to three adaptation hot-spots located within and between capsomers. The second-site suppressor mutations act by restoring the formation of pentamers lost upon K25 mutation, enabling closed conical capsid assembly both in vitro and inside virions. These results indicate that there is no intrinsic requirement for K25 in either nucleotide import or capsid assembly. We propose that whilst HIV-1 must maintain a precise hexamer:pentamer equilibrium for proper capsid assembly, compensatory mutations can tune this equilibrium to restore fitness lost by mutation of the central pore.
Assuntos
Proteínas do Capsídeo , Capsídeo , HIV-1 , Mutação , Montagem de Vírus , Replicação Viral , HIV-1/genética , HIV-1/fisiologia , Montagem de Vírus/genética , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Proteínas do Capsídeo/química , Capsídeo/metabolismo , Humanos , Replicação Viral/genética , Vírion/metabolismo , Vírion/genética , Células HEK293 , Infecções por HIV/virologia , Infecções por HIV/genéticaRESUMO
Pathogenic changes in gut microbial composition precede the onset of HIV-1 infection in men who have sex with men (MSM). This process is associated with increased levels of systemic inflammatory biomarkers and risk for AIDS development. Using mediation analysis framework, in this report we link the effects of unprotected receptive intercourse among MSM prior to primary HIV-1 infection to higher levels of proinflammatory cytokines sCD14 and sCD163 in plasma and a significant decrease in the abundance of A. muciniphila, B. caccae, B. fragilis, B. uniformis, Bacteroides spp., Butyricimonas spp., and Odoribacter spp., and a potential increase in the abundance of Dehalobacterium spp. and Methanobrevibacter spp. in stools of MSM with the highest number of sexual partners. These differences in microbiota, together with a reduction in the pairwise correlations among commensal and short-chain fatty acid-producing bacteria with a number of sexual partners, support an increase in gut dysbiosis with the number of sexual partners. These results demonstrate the interconnectedness of sexual behavior, immune response, and microbiota composition, notably among MSM participating in high-risk sexual behaviors.
Assuntos
Microbioma Gastrointestinal , Infecções por HIV , HIV-1 , Homossexualidade Masculina , Inflamação , Comportamento Sexual , Masculino , Humanos , Infecções por HIV/microbiologia , Infecções por HIV/imunologia , Infecções por HIV/virologia , Adulto , Inflamação/microbiologia , HIV-1/fisiologia , Disbiose/microbiologia , Pessoa de Meia-IdadeRESUMO
HIV-1 infection requires passage of the viral core through the nuclear pore of the cell, a process that depends on functions of the viral capsid. Recent studies have shown that HIV-1 cores enter the nucleus prior to capsid disassembly. Interactions of the viral capsid with the nuclear pore complex are necessary but not sufficient for nuclear entry, and the mechanism by which the viral core traverses the comparably sized nuclear pore is unknown. Here we show that the HIV-1 core is highly elastic and that this property is linked to nuclear entry and infectivity. Using atomic force microscopy-based approaches, we found that purified wild type cores rapidly returned to their normal conical morphology following a severe compression. Results from independently performed molecular dynamic simulations of the mature HIV-1 capsid also revealed its elastic property. Analysis of four HIV-1 capsid mutants that exhibit impaired nuclear entry revealed that the mutant viral cores are brittle. Adaptation of two of the mutant viruses in cell culture resulted in additional substitutions that restored elasticity and rescued infectivity and nuclear entry. We also show that capsid-targeting compound PF74 and the antiviral drug Lenacapavir reduce core elasticity and block HIV-1 nuclear entry at concentrations that preserve interactions between the viral core and the nuclear envelope. Our results indicate that elasticity is a fundamental property of the HIV-1 core that enables nuclear entry, thereby facilitating infection. These results provide new insights into the role of the capsid in HIV-1 nuclear entry and the antiviral mechanisms of HIV-1 capsid inhibitors.
Assuntos
Elasticidade , Infecções por HIV , HIV-1 , HIV-1/fisiologia , Humanos , Infecções por HIV/virologia , Infecções por HIV/metabolismo , Internalização do Vírus , Capsídeo/metabolismo , Núcleo Celular/metabolismo , Núcleo Celular/virologia , Simulação de Dinâmica Molecular , Microscopia de Força Atômica , Poro Nuclear/metabolismo , Indóis , Fenilalanina/análogos & derivadosRESUMO
HIV-1 virion maturation is an essential step in the viral replication cycle to produce infectious virus particles. Gag and Gag-Pol polyproteins are assembled at the plasma membrane of the virus-producer cells and bud from it to the extracellular compartment. The newly released progeny virions are initially immature and noninfectious. However, once the Gag polyprotein is cleaved by the viral protease in progeny virions, the mature capsid proteins assemble to form the fullerene core. This core, harboring two copies of viral genomic RNA, transforms the virion morphology into infectious virus particles. This morphological transformation is referred to as maturation. Virion maturation influences the distribution of the Env glycoprotein on the virion surface and induces conformational changes necessary for the subsequent interaction with the CD4 receptor. Several host factors, including proteins like cyclophilin A, metabolites such as IP6, and lipid rafts containing sphingomyelins, have been demonstrated to have an influence on virion maturation. This review article delves into the processes of virus maturation and Env glycoprotein recruitment, with an emphasis on the role of host cell factors and environmental conditions. Additionally, we discuss microscopic technologies for assessing virion maturation and the development of current antivirals specifically targeting this critical step in viral replication, offering long-acting therapeutic options.
Assuntos
HIV-1 , Vírion , Montagem de Vírus , Replicação Viral , HIV-1/fisiologia , HIV-1/efeitos dos fármacos , Humanos , Vírion/metabolismo , Vírion/fisiologia , Infecções por HIV/virologia , Infecções por HIV/tratamento farmacológico , Fármacos Anti-HIV/farmacologia , Produtos do Gene gag do Vírus da Imunodeficiência Humana/metabolismoRESUMO
More than 80 million people worldwide have been infected with the human immunodeficiency virus (HIV). There are now approximately 39 million individuals living with HIV/acquired immunodeficiency syndrome (AIDS). Although treatments against HIV infection are available, AIDS remains a serious disease. Combination antiretroviral therapy (cART), also known as highly active antiretroviral therapy (HAART), consists of treatment with a combination of several antiretroviral drugs that block multiple stages in the virus replication cycle. However, the increasing usage of cART is inevitably associated with the emergence of HIV drug resistance. In addition, the development of persistent cellular reservoirs of latent HIV is a critical obstacle to viral eradication since viral rebound takes place once anti-retroviral therapy (ART) is interrupted. Thus, several efforts are being applied to new generations of drugs, vaccines and new types of cART. In this review, we summarize the antiviral therapies used for the treatment of HIV/AIDS, both as individual agents and as combination therapies, and highlight the role of both macrophages and HIV cellular reservoirs and the most recent clinical studies related to this disease.
Assuntos
Infecções por HIV , HIV-1 , Macrófagos , Latência Viral , Humanos , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , Macrófagos/virologia , Macrófagos/efeitos dos fármacos , Latência Viral/efeitos dos fármacos , HIV-1/efeitos dos fármacos , HIV-1/fisiologia , Fármacos Anti-HIV/uso terapêutico , Fármacos Anti-HIV/farmacologia , Terapia Antirretroviral de Alta Atividade , Reservatórios de Doenças/virologia , Replicação Viral/efeitos dos fármacos , AnimaisRESUMO
Over the past three years, new SARS-CoV-2 variants have continuously emerged, evolving to a point where an immune response against the original vaccine no longer provided optimal protection against these new strains. During this time, high-throughput neutralization assays based on pseudoviruses have become a valuable tool for assessing the efficacy of new vaccines, screening updated vaccine candidates against emerging variants, and testing the efficacy of new therapeutics such as monoclonal antibodies. Lentiviral vectors derived from HIV-1 are popular for developing pseudo and chimeric viruses due to their ease of use, stability, and long-term transgene expression. However, the HIV-based platform has lower transduction rates for pseudotyping coronavirus spike proteins than other pseudovirus platforms, necessitating more optimized methods. As the SARS-CoV-2 virus evolved, we produced over 18 variants of the spike protein for pseudotyping with an HIV-based vector, optimizing experimental parameters for their production and transduction. In this article, we present key parameters that were assessed to improve such technology, including (a) the timing and method of collection of pseudovirus supernatant; (b) the timing of host cell transduction; (c) cell culture media replenishment after pseudovirus adsorption; and (d) the centrifugation (spinoculation) parameters of the host cell+ pseudovirus mix, towards improved transduction. Additionally, we found that, for some pseudoviruses, the addition of a cationic polymer (polybrene) to the culture medium improved the transduction process. These findings were applicable across variant spike pseudoviruses that include not only SARS-CoV-2 variants, but also SARS, MERS, Alpha Coronavirus (NL-63), and bat-like coronaviruses. In summary, we present improvements in transduction efficiency, which can broaden the dynamic range of the pseudovirus titration and neutralization assays.
Assuntos
HIV-1 , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Transdução Genética , Humanos , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Glicoproteína da Espícula de Coronavírus/imunologia , SARS-CoV-2/genética , SARS-CoV-2/fisiologia , HIV-1/genética , HIV-1/fisiologia , Células HEK293 , Pseudotipagem Viral , Vetores Genéticos/genética , COVID-19/virologia , Testes de NeutralizaçãoRESUMO
The productive replication of human immunodeficiency virus type 1 (HIV-1) involves intricate interactions between viral proteins and host cell machinery. However, the contributions of the lysosomal pathways for HIV-1 replication are not fully understood. The goal of this study was to determine the impact of lysosome-targeting compounds on HIV-1 replication and identify the cellular changes that are linked to HIV-1 inhibition using cell culture models of HIV-1 infection. Here, we demonstrate that the treatment of cells with various pharmacological agents known to inhibit lysosomal functions interfere with HIV-1 replication. The vacuolar ATPase (V-ATPase) inhibitor bafilomycin A1 exerted a potent inhibition of HIV-1 replication. Bafilomycin A1 inhibition of HIV-1 was independent of coreceptor tropism of HIV-1. Our data suggest that bafilomycin A1 inhibits HIV-1 at the post-integration steps of the virus life cycle, which include viral gene expression, virus assembly, and/or egress. Analysis of the cellular alterations following bafilomycin A1 treatment indicates that bafilomycin A1 causes a disruption in lysosome structure and functions. Treatment of cells with bafilomycin A1 caused an accumulation of unesterified cholesterol in lysosomes along with the expansion of the lysosomal compartments. Interestingly, the overexpression of the lysosomal cholesterol transporter Niemann-Pick type C 1 (NPC1) partially relieved bafilomycin A1 inhibition of HIV-1. Collectively, our data suggest that bafilomycin A1 inhibits HIV-1 replication in part by disrupting the lysosomal cholesterol trafficking pathway.
Assuntos
Colesterol , Infecções por HIV , HIV-1 , Lisossomos , Macrolídeos , Humanos , Transporte Biológico/efeitos dos fármacos , Linhagem Celular , Colesterol/metabolismo , Infecções por HIV/virologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/metabolismo , HIV-1/efeitos dos fármacos , HIV-1/fisiologia , Lisossomos/metabolismo , Lisossomos/efeitos dos fármacos , Macrolídeos/farmacologia , Replicação Viral/efeitos dos fármacosRESUMO
Our examination of RNA helicases for effects on HIV-1 protein production and particle assembly identified Rocaglamide (RocA), a known modulator of eIF4A1 function, as an inhibitor of HIV-1 replication in primary CD4+ T cells and three cell systems. HIV-1 attenuation by low-nM RocA doses was associated with reduced viral particle formation without a marked decrease in Gag production. Rather, the co-localization of Gag and HIV-1 genomic RNA (gRNA) assemblies was impaired by RocA treatment in a reversible fashion. Ribonucleoprotein (RNP) immunoprecipitation studies recapitulated the loss of Gag-gRNA assemblies upon RocA treatment. Parallel biophysical studies determined that neither RocA nor eIF4A1 independently affected the ability of Gag to interact with viral RNA, but together, they distorted the structure of the HIV-1 RNP visualized by electron microscopy. Taken together, several lines of evidence indicate that RocA induces stable binding of eIF4A1 onto the viral RNA genome in a manner that interferes with the ordered assembly of Gag along Gag-gRNA assemblies required to generate infectious virions.
Assuntos
Benzofuranos , HIV-1 , RNA Viral , Replicação Viral , Produtos do Gene gag do Vírus da Imunodeficiência Humana , HIV-1/efeitos dos fármacos , HIV-1/fisiologia , HIV-1/genética , Humanos , Replicação Viral/efeitos dos fármacos , RNA Viral/metabolismo , RNA Viral/genética , Produtos do Gene gag do Vírus da Imunodeficiência Humana/metabolismo , Produtos do Gene gag do Vírus da Imunodeficiência Humana/genética , Benzofuranos/farmacologia , Vírion/efeitos dos fármacos , Vírion/metabolismo , Linfócitos T CD4-Positivos/virologia , Montagem de Vírus/efeitos dos fármacos , Infecções por HIV/virologia , Infecções por HIV/tratamento farmacológico , Fator de Iniciação 4A em Eucariotos/metabolismo , Genoma Viral/efeitos dos fármacos , Ligação Proteica , Linhagem CelularRESUMO
The persistence of HIV-1 in long-lived latent reservoirs during suppressive antiretroviral therapy (ART) remains one of the principal barriers to a functional cure. Blocks to transcriptional elongation play a central role in maintaining the latent state, and several latency reversal strategies focus on the release of positive transcription elongation factor b (P-TEFb) from sequestration by negative regulatory complexes, such as the 7SK complex and BRD4. Another major cellular reservoir of P-TEFb is in Super Elongation Complexes (SECs), which play broad regulatory roles in host gene expression. Still, it is unknown if the release of P-TEFb from SECs is a viable latency reversal strategy. Here, we demonstrate that the SEC is not required for HIV-1 replication in primary CD4+ T cells and that a small molecular inhibitor of the P-TEFb/SEC interaction (termed KL-2) increases viral transcription. KL-2 acts synergistically with other latency reversing agents (LRAs) to reactivate viral transcription in several cell line models of latency in a manner that is, at least in part, dependent on the viral Tat protein. Finally, we demonstrate that KL-2 enhances viral reactivation in peripheral blood mononuclear cells (PBMCs) from people living with HIV (PLWH) on suppressive ART, most notably in combination with inhibitor of apoptosis protein antagonists (IAPi). Taken together, these results suggest that the release of P-TEFb from cellular SECs may be a novel route for HIV-1 latency reactivation.
Assuntos
Linfócitos T CD4-Positivos , Infecções por HIV , HIV-1 , Fator B de Elongação Transcricional Positiva , Latência Viral , HIV-1/fisiologia , HIV-1/genética , Humanos , Latência Viral/fisiologia , Latência Viral/efeitos dos fármacos , Fator B de Elongação Transcricional Positiva/metabolismo , Infecções por HIV/virologia , Infecções por HIV/metabolismo , Infecções por HIV/tratamento farmacológico , Linfócitos T CD4-Positivos/virologia , Linfócitos T CD4-Positivos/metabolismo , Ativação Viral/efeitos dos fármacos , Replicação Viral , Regulação Viral da Expressão GênicaRESUMO
BACKGROUND: Infection of astrocytes by Human Immunodeficiency Virus (HIV-1) remains a topic of debate, with conflicting data, yet instances of astrocytes containing viral DNA have been observed in vivo. In this study, we aimed to elucidate potential routes through which astrocytes could be infected and their ability to produce infectious particles using primary human astrocytes. METHODS: We infected primary astrocytes derived from either neuroprogenitor cells (NPCs) or induced pluripotent stem cells (iPSCs) that express both C-X-C chemokine receptor type 4 (CXCR4) and the C-C chemokine receptor type 5 (CCR5) coreceptors, using either cell-free HIV-1 virus directly or cell-associated virus indirectly through infected macrophages and microglia. RESULTS: Low-level infectivity by cell-free viruses was primarily attributed to a defect in the entry process. Bypassing HIV-specific receptor-mediated entry using pseudotyped viruses resulted in productive infection and the release of infectious particles. CONCLUSIONS: These findings suggest that astrocytes may be one of the potential sources of neurotoxicity in HIV-associated neurocognitive disorders (HAND) and could possibly act as reservoirs for HIV in the central nervous system (CNS).
Assuntos
Astrócitos , HIV-1 , Astrócitos/virologia , Astrócitos/metabolismo , Humanos , HIV-1/fisiologia , Células Cultivadas , Células-Tronco Pluripotentes Induzidas/virologia , Células-Tronco Neurais/virologia , Células-Tronco Neurais/metabolismo , Receptores CXCR4/metabolismo , Receptores CCR5/metabolismo , Infecções por HIVRESUMO
The viral capsid performs critical functions during HIV-1 infection and is a validated target for antiviral therapy. Previous studies have established that the proper structure and stability of the capsid are required for efficient HIV-1 reverse transcription in target cells. Moreover, it has recently been demonstrated that permeabilized virions and purified HIV-1 cores undergo efficient reverse transcription in vitro when the capsid is stabilized by addition of the host cell metabolite inositol hexakisphosphate (IP6). However, the molecular mechanism by which the capsid promotes reverse transcription is undefined. Here we show that wild type HIV-1 virions can undergo efficient reverse transcription in vitro in the absence of a membrane-permeabilizing agent. This activity, originally termed "natural endogenous reverse transcription" (NERT), depends on expression of the viral envelope glycoprotein during virus assembly and its incorporation into virions. Truncation of the gp41 cytoplasmic tail markedly reduced NERT activity, suggesting that gp41 licenses the entry of nucleotides into virions. By contrast to reverse transcription in permeabilized virions, NERT required neither the addition of IP6 nor a mature capsid, indicating that an intact viral membrane can substitute for the function of the viral capsid during reverse transcription in vitro. Collectively, these results demonstrate that the viral capsid functions as a nanoscale container for reverse transcription during HIV-1 infection.
Assuntos
Capsídeo , HIV-1 , Transcrição Reversa , HIV-1/fisiologia , HIV-1/metabolismo , Capsídeo/metabolismo , Humanos , Vírion/metabolismo , Proteína gp41 do Envelope de HIV/metabolismo , Proteína gp41 do Envelope de HIV/genética , Montagem de Vírus/fisiologia , Infecções por HIV/virologia , Infecções por HIV/metabolismo , Ácido Fítico/metabolismoRESUMO
Autophagy is an evolutionarily ancient catabolic pathway and has recently emerged as an integral part of the innate immune system. While the core machinery of autophagy is well defined, the physiological regulation of autophagy is less understood. Here, we identify a C-terminal fragment of human hemoglobin A (HBA1, amino acids 111-132) in human bone marrow as a fast-acting non-inflammatory inhibitor of autophagy initiation. It is proteolytically released from full-length HBA1 by cathepsin E, trypsin or pepsin. Biochemical characterization revealed that HBA1(111-132) has an in vitro stability of 52 min in human plasma and adopts a flexible monomeric conformation in solution. Structure-activity relationship studies revealed that the C-terminal 13 amino acids of HBA1(120-132) are sufficient to inhibit autophagy, two charged amino acids (D127, K128) mediate solubility, and two serines (S125, S132) are required for function. Successful viruses like human immunodeficiency virus 1 (HIV-1) evolved strategies to subvert autophagy for virion production. Our results show that HBA1(120-132) reduced virus yields of lab-adapted and primary HIV-1. Summarizing, our data identifies naturally occurring HBA1(111-132) as a physiological, non-inflammatory antagonist of autophagy. Optimized derivatives of HBA1(111-132) may offer perspectives to restrict autophagy-dependent viruses.
Assuntos
Autofagia , HIV-1 , Humanos , HIV-1/metabolismo , HIV-1/fisiologia , Relação Estrutura-Atividade , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/farmacologia , Sequência de AminoácidosRESUMO
Different host proteins target different HIV proteins and antagonize their functions, depending on the stage of the HIV life cycle and the stage of infection. Concurrently, HIV proteins also target and antagonize various different host proteins to facilitate HIV replication within host cells. The preceding quite specific area of knowledge in HIV pathogenesis, however, remains insufficiently understood. We therefore propose, in this review article, to examine and discuss the HIV proteins that counteract those host restriction proteins which results directly in increased infectivity of HIV. We elaborate on HIV proteins that antagonize host cellular proteins to promote HIV replication, and thus HIV infection. We examine the functions and mechanisms via which Nef, Vif, Vpu, Env, Vpr, and Vpx counteract host proteins such as Ser5, PSGL-1, IFITMS, A3G, tetherin, GBP5, SAMHD1, STING, HUSH, REAF, and TET2 to increase HIV infectivity. Nef antagonizes three host proteins, viz., Ser5, PSGL1, and IFITIMs, while Vpx also antagonizes three host restriction factors, viz., SAMHD1, STING, and HUSH complex; therefore, these proteins may be potential candidates for therapeutic intervention in HIV infection. Tetherin is targeted by Vpu and Env, PSGL1 is targeted by Nef and Vpu, while Ser5 is targeted by Nef and Env proteins. Finally, conclusive remarks and future perspectives are also presented.
Assuntos
Infecções por HIV , HIV-1 , Interações Hospedeiro-Patógeno , Proteínas do Vírus da Imunodeficiência Humana , Humanos , Infecções por HIV/metabolismo , Infecções por HIV/virologia , Infecções por HIV/imunologia , Proteínas do Vírus da Imunodeficiência Humana/metabolismo , HIV-1/fisiologia , Replicação Viral , Animais , Fatores de Restrição AntiviraisRESUMO
Tunneling nanotubes (TNTs) are cellular connections, which represent a novel route for cell-to-cell communication. Strong evidence points to a role for TNTs in the intercellular transfer of signals, molecules, organelles, and pathogens, involving them in many cellular functions. In myeloid cells (e.g., monocytes/macrophages, dendritic cells, and osteoclasts), intercellular communication via TNT contributes to their differentiation and immune functions, by favoring material and pathogen transfer, as well as cell fusion. This chapter addresses the complexity of the definition and characterization of TNTs in myeloid cells, the different processes involved in their formation, their existence in vivo, and finally their function(s) in health and infectious diseases, with the example of HIV-1 infection.
Assuntos
Comunicação Celular , Células Mieloides , Humanos , Comunicação Celular/fisiologia , Animais , Infecções por HIV/imunologia , HIV-1/fisiologia , Estruturas da Membrana Celular , NanotubosRESUMO
HIV-1 polymerase, commonly known as HIV reverse transcriptase (RT), catalyzes the critical reaction of reverse transcription by synthesizing a double-stranded DNA copy of the viral genomic RNA. During the replication cycle, this synthesized DNA is integrated into the host genome. This entire process is essential for viral replication and is targeted by several antiviral drugs. Numerous studies in biochemistry and structural biology have led to a good understanding of HIV-1 RT functions. However, the discovery of epitranscriptomic marks, such as 2'-O-methylations, on the HIV-1 RNA genome raise the questions about RT's ability to copy RNAs decorated with these biochemical modifications. This review focuses on the importance of RT in the viral cycle, its structure and function and the impact of 2'-O-methylations on its activity and replication regulation, particularly in quiescent cells.
Assuntos
Transcriptase Reversa do HIV , HIV-1 , Replicação Viral , Transcriptase Reversa do HIV/metabolismo , Transcriptase Reversa do HIV/genética , Transcriptase Reversa do HIV/química , HIV-1/fisiologia , HIV-1/genética , Humanos , Metilação , RNA Viral/metabolismo , RNA Viral/genética , Transcrição Reversa , Infecções por HIV/virologia , Infecções por HIV/tratamento farmacológicoRESUMO
While antiretroviral therapy (ART) has revolutionized the management of human immunodeficiency virus (HIV) and has enabled people living with HIV (PLWH) to achieve near-normal life expectancies, an HIV cure remains elusive due to the presence of HIV reservoirs. Furthermore, compared with individuals in the general population, PLWH support a higher burden of multimorbidity, including pulmonary diseases of both an infectious and non-infection nature, which may be a consequence of the formation of HIV reservoirs. Their gut, lymph nodes, brain, testes and lungs constitute important anatomic sites for the reservoirs. While CD4+ T cells, and particularly memory CD4+ T cells, are the best characterized cellular HIV reservoirs, tissue resident macrophages (TRM) and alveolar macrophages (AM) also harbor HIV infection. AM are the most abundant cells in bronchoalveolar (BAL) fluid in healthy conditions, and act as sentinels in the alveolar space by patrolling and clearing debris, microbes and surfactant recycling. Long-lived tissue-resident AM of embryonic origin have the capacity of self-renewal without replenishment from peripheral monocytes. As in other tissues, close cell-cell contacts in lungs also provide a milieu conducive for cell-to-cell spread of HIV infection and establishment of reservoirs. As lungs are in constant exposure to antigens from the external environment, this situation contributes to pro-inflammatory phenotype rendering pulmonary immune cells exhausted and senescent-an environment facilitating HIV persistence. Factors such as tobacco and e-cigarette smoking, lung microbiome dysbiosis and respiratory coinfections further drive antigenic stimulation and HIV replication. HIV replication, in turn, contributes to ongoing inflammation and clonal expansion. Herein, the potential role of AM in HIV persistence is discussed. Furthermore, their contribution towards pulmonary inflammation and immune dysregulation, which may in turn render PLWH susceptible to chronic lung disease, despite ART, is explored. Finally, strategies to eliminate HIV-infected AM are discussed.
Assuntos
Infecções por HIV , Pneumopatias , Macrófagos Alveolares , Humanos , Infecções por HIV/imunologia , Infecções por HIV/virologia , Infecções por HIV/complicações , Macrófagos Alveolares/virologia , Macrófagos Alveolares/imunologia , Macrófagos Alveolares/fisiologia , Pneumopatias/virologia , Pneumopatias/imunologia , Pulmão/virologia , Pulmão/imunologia , HIV-1/fisiologia , Reservatórios de Doenças/virologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/virologiaRESUMO
While antiretroviral therapy (ART) has revolutionized the management of human immunodeficiency virus (HIV) and has enabled people living with HIV (PLWH) to achieve near-normal life expectancies, an HIV cure remains elusive due to the presence of HIV reservoirs. Furthermore, compared with individuals in the general population, PLWH support a higher burden of multimorbidity, including pulmonary diseases of both an infectious and non-infection nature, which may be a consequence of the formation of HIV reservoirs. Their gut, lymph nodes, brain, testes and lungs constitute important anatomic sites for the reservoirs. While CD4+ T-cells, and particularly memory CD4+ T-cells, are the best characterized cellular HIV reservoirs, tissue resident macrophages (TRM) and alveolar macrophages (AM) also harbor HIV infection. AM are the most abundant cells in bronchoalveolar (BAL) fluid in healthy conditions, and act as sentinels in the alveolar space by patrolling and clearing debris, microbes and surfactant recycling. Long-lived tissue-resident AM of embryonic origin have the capacity of self-renewal without replenishment from peripheral monocytes. As in other tissues, close cell-cell contacts in lungs also provide a milieu conducive for cell-to-cell spread of HIV infection and establishment of reservoirs. As lungs are in constant exposure to antigens from the external environment, this situation contributes to pro-inflammatory phenotype rendering pulmonary immune cells exhausted and senescent-an environment facilitating HIV persistence. Factors such as tobacco and e-cigarette smoking, lung microbiome dysbiosis and respiratory co-infections further drive antigenic stimulation and HIV replication. HIV replication, in turn, contributes to ongoing inflammation and clonal expansion. Herein, the potential role of AM in HIV persistence is discussed. Furthermore, their contribution towards pulmonary inflammation and immune dysregulation, which may in turn render PLWH susceptible to chronic lung disease, despite ART, is explored. Finally, strategies to eliminate HIV-infected AM are discussed.
Assuntos
Infecções por HIV , Pneumopatias , Macrófagos Alveolares , Humanos , Infecções por HIV/imunologia , Infecções por HIV/virologia , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Macrófagos Alveolares/virologia , Macrófagos Alveolares/imunologia , Macrófagos Alveolares/fisiologia , Pneumopatias/virologia , Pneumopatias/imunologia , HIV-1/fisiologia , Pulmão/virologia , Pulmão/imunologia , Reservatórios de Doenças/virologiaRESUMO
HIV-1, the causative agent of AIDS, is a retrovirus that packages two copies of unspliced viral RNA as a dimer into newly budding virions. The unspliced viral RNA also serves as an mRNA template for translation of two polyproteins. Recent studies suggest that the fate of the viral RNA (genome or mRNA) is determined at the level of transcription. RNA polymerase II uses heterogeneous transcription start sites to generate major transcripts that differ in only two guanosines at the 5' end. Remarkably, this two-nucleotide difference is sufficient to alter the structure of the 5'-untranslated region and generate two pools of RNA with distinct functions. The presence of both RNA species is needed for optimal viral replication and fitness.