Project description:Type I interferon plays a critical role in the control of viral infections, including HIV-1. Interferon induces a number of restriction factors that block HIV-1 entry, replication and release from the host cell. Currently, systemic treatment of HIV-1 infection with interferon has little efficacy in the clinic due to side effects including fatigue and flu-like symptoms. However, understanding the role of interferon in HIV-1 restriction, and developing molecular tools to generate type I interferons locally, provide an opportunity to inhibit HIV-1 replication while avoiding the side effects associated with systemic administration. Here, we tested a constitutively active inducer of high levels of interferon beta (dLMP1-MAVS). Supernatant from cell transfected with dLMP1-MAVS inhibited HIV-1 replication in both culture cells and primary human CD4+ T cells. CD4+ T cells upregulated a number of known HIV-1 restriction factors, including Viperin, Tetherin, MxB, and ISG56 in response to dLMP1-MAVS. In addition, dLMP1-MAVS activated human dendritic and acted as a molecular adjuvant in a mouse HIV-1 vaccine model. Our study generates new insights into the role of type I interferon in HIV-1 restriction, and provides a novel strategy to induce both type I interferon and anti-HIV-1 immune responses at sites of ongoing viral replication.
Project description:Interferon (IFN) inhibits HIV replication by inducing an array of antiviral effectors. Here we describe a novel CRISPR knockout screening approach to identify the ensemble of these HIV restriction factors. We assembled a CRISPR sgRNA library specific for Interferon Stimulated Genes (ISGs) into a modified lentiviral vector that allows for packaging of sgRNA-encoding genomes in trans into budding HIV-1 particles. We observed that knockout of Zinc Antiviral Protein (ZAP) improved the performance of the screen due to ZAP-mediated inhibition of the vector. We identify a small panel of IFN-induced HIV restriction factors, including MxB, IFITM1, Tetherin/BST2 and TRIM5 which together explain the inhibitory effects of IFN on the HIV-1 LAI strain in THP-1 cells. Further, we identify novel HIV dependency factors, including SEC62 and TLR2. The ability of IFN-induced restriction factors to inhibit an HIV strain to replicate in human cells suggests that these human restriction factors are incompletely antagonized.
Project description:Interferon ε (IFNε) is a unique type I IFN that is not induced by pattern-recognition response elements. IFNε is constitutively expressed in mucosal tissues including the female genital mucosa. We show here that IFNε induces an antiviral state in human macrophages that blocks HIV-1 replication. In this work, we examined effects and underlying mechanisms of IFNε in HIV infection of monocyte-derived macrophages (MDMs). We found that IFNε blocked HIV replication in macrophages. It acted on early stages of the HIV life cycle including entry and reverse transcription. It did not appear to operate through known IFN-induced HIV host restriction factors. IFNε induced immune responses in primary macrophages distinct from those induced by IFNα. Importantly, we discovered a novel protective effect of IFNε in primary macrophages against HIV by surging reactive oxygen species (ROS).
Project description:We found that fuse ΔLMP1 to MAVS could strengthen MAVS mediated inhibition of PRRSV replication in MARC-145 cells. To better understand the biological function of the fusion protein ΔLMP1-MAVS, overall gene expression of MARC-145 cells transfected with ΔLMP1-MAVS or MAVS was evaluated by mRNA-seq. The result showed that ΔLMP1-MAVS upregulated a number of genes associated with innate immune responses to viral infection, including plenty of interferon-stimulated genes. This study provides reference date to research the working mechanism of ΔLMP1-MAVS.
Project description:Transcriptional profiling of HeLa cells comparing control untreated HeLa cells with IFN-gamma-treated HeLa cells To infect host cells, many viruses use small cellular compartments, called endosomes, for entry, and the thiol/disulfide interchange in viral envelope glycoproteins (Envs) is crucial for infection. By screening cysteine-reacting chemicals, we found a compound, 4,4’-dithiopyridine, which is active at acidic pH, efficiently restricts retrovirus vector infection. We thus hypothesized that some products of endosome-localized, interferon-stimulated genes (ISGs) exhibit anti-viral activity by inhibiting thiol/disulfide interchange in viral Envs. Among the hundreds of ISGs, gamma-interferon (IFN)-inducible lysosomal thiolreductase (GILT) is the only molecule that resides in the endosomes/lysosomes and digests the S-S bonds of proteins under acidic conditions. We now report that GILT significantly inhibits the replication of retroviruses, including HIV-1 and MLV, by restricting both the early and late phases of their life cycles. Using the VSV-G pseudotyped HIV-1 model, we found that GILT digests the S-S bonds of viral Env proteins. GILT also inhibits HIV-1 viral release by digesting the S-S bond of CD63, an endosome-localized molecule reportedly involved in HIV-1 particle release. The effect of -IFN on HIV-1 is limited, although GILT induced by gamma-IFN is supposed to have anti-HIV-1 activity. We found that while gamma-IFN effectively inhibits MLV replication through GILT, the gamma-IFN signaling is remarkably inhibited by the HIV-1 Env protein, but not the MLV Env protein. These findings suggest that GILT functions as an anti-viral host factor induced by gamma-IFN, however, HIV-1 may have evolved to inhibit gamma-IFN signaling by the Env protein.
Project description:All major types of interferon (IFN) efficiently inhibit hepatitis C virus (HCV) replication in vitro and in vivo. Remarkably, HCV replication is not sensitive to IFN? in the hepatoma cell line Huh6, despite an intact signaling pathway. We performed transcriptome analyses between Huh6 and Huh-7 to identify effector genes of the IFN? response and thereby identified the DExD/H box helicase DDX60L as a restriction factor of HCV replication. DDX60L and its homolog DDX60 were both induced upon viral infection and IFN treatment in primary human hepatocytes. However, exclusively DDX60L knockdown increased HCV replication in Huh-7 cells, and rescued HCV replication from type II IFN as well as type I and III IFN treatment, suggesting that DDX60L is an important effector protein of the innate immune response against HCV. DDX60L had no impact on replication of hepatitis A virus (HAV), but severely impaired production of lentiviral vectors, arguing for a potential antiretroviral activity. Detection of endogenous DDX60L protein turned out to be difficult due to instability. DDX60L knockdown did not alter interferon stimulated gene (ISG) induction after IFN treatment, suggesting that it is a direct effector of the innate immune response. It most likely inhibits viral RNA replication, since we found no impact of DDX60L on translation or stability of HCV subgenomic replicons, nor additional impact on entry and assembly of infectious virus. Similar to its homolog DDX60, DDX60L had a moderate impact on retinoic acid-inducible gene I (RIG-I)-dependent activation of innate immunity arguing for additional functions in the sensing of viral RNA. Gene Expression was compared between two cell lines, Huh6 and Huh7, under interferon-gamma or interferon-alpha treatment. We intended to identify genes that are more strongly upregulated in Huh-7 than in Huh6 in response to interferon treatment.
Project description:During HIV-1 infection, there is a massive perturbation of host gene expression, but as yet, genome-wide studies have not identified host genes affecting HIV-1 replication in lymphatic tissue, the primary site of virus-host interactions. In this study, we isolated RNA from the inguinal lymph nodes of 22 HIV-1-infected individuals and utilized a microarray approach to identify host genes critically important for viral replication in lymphatic tissue by examining gene expression associated with viral load. Strikingly, ~95% of the transcripts (558) in this data set (592 transcripts total) were negatively associated with HIV-1 replication. Genes in this subset (1) inhibit cellular activation/proliferation (ex.: TCFL5, SOCS5 and SCOS7, KLF10), (2) promote heterochromatin formation (ex.: HIC2, CREBZF, ZNF148/ZBP-89), (3) increase collagen synthesis (ex.: PLOD2, POSTN, CRTAP), and (4) reduce cellular transcription and translation. Potential anti-HIV-1 restriction factors were also identified (ex.: NR3C1, HNRNPU, PACT). Only ~5% of the transcripts (34) were positively associated with HIV-1 replication. Paradoxically, nearly all these genes function in innate and adaptive immunity, particularly highlighting a heightened interferon system. The predominance of negative correlations as well as the disconnect between host defenses and viral load point to the importance of genes that regulate target cell activation and genes that code for potentially new restriction factors as determinants of viral load rather than conventional host defenses.
Project description:During HIV-1 infection, there is a massive perturbation of host gene expression, but as yet, genome-wide studies have not identified host genes affecting HIV-1 replication in lymphatic tissue, the primary site of virus-host interactions. In this study, we isolated RNA from the inguinal lymph nodes of 22 HIV-1-infected individuals and utilized a microarray approach to identify host genes critically important for viral replication in lymphatic tissue by examining gene expression associated with viral load. Strikingly, ~95% of the transcripts (558) in this data set (592 transcripts total) were negatively associated with HIV-1 replication. Genes in this subset (1) inhibit cellular activation/proliferation (ex.: TCFL5, SOCS5 and SCOS7, KLF10), (2) promote heterochromatin formation (ex.: HIC2, CREBZF, ZNF148/ZBP-89), (3) increase collagen synthesis (ex.: PLOD2, POSTN, CRTAP), and (4) reduce cellular transcription and translation. Potential anti-HIV-1 restriction factors were also identified (ex.: NR3C1, HNRNPU, PACT). Only ~5% of the transcripts (34) were positively associated with HIV-1 replication. Paradoxically, nearly all these genes function in innate and adaptive immunity, particularly highlighting a heightened interferon system. The predominance of negative correlations as well as the disconnect between host defenses and viral load point to the importance of genes that regulate target cell activation and genes that code for potentially new restriction factors as determinants of viral load rather than conventional host defenses. Total RNA was isolated from the inguinal lymph nodes of 22 HIV-1-infected subjects at different clinical stages (and varying viral loads) and prepared for RNA extraction and hybridization on Affymetrix Human Genome U133 Plus 2.0 microarrays. Replicate arrays were performed for lymph node samples to minimize assay noise and host genes critically important for viral replication in lymphatic tissue were identified by examining gene expression and its association with viral load. Replicates were not performed for samples WB91 and TS35 due to limited amounts of biomaterial.
Project description:Aguilera 2014 - HIV latency. Interaction
between HIV proteins and immune response
This model is described in the article:
Studying HIV latency by
modeling the interaction between HIV proteins and the innate
immune response.
Aguilera LU,
Rodríguez-González J.
J. Theor. Biol. 2014 Nov; 360:
67-77
Abstract:
HIV infection leads to two cell fates, the viral productive
state or viral latency (a reversible non-productive state). HIV
latency is relevant because infected active CD4+ T-lymphocytes
can reach a resting memory state in which the provirus remains
silent for long periods of time. Despite experimental and
theoretical efforts, the causal molecular mechanisms
responsible for HIV latency are only partially understood.
Studies have determined that HIV latency is influenced by the
innate immune response carried out by cell restriction factors
that inhibit the postintegration steps in the virus replication
cycle. In this study, we present a mathematical study that
combines deterministic and stochastic approaches to analyze the
interactions between HIV proteins and the innate immune
response. Using wide ranges of parameter values, we observed
the following: (1) a phenomenological description of the viral
productive and latent cell phenotypes is obtained by bistable
and bimodal dynamics, (2) biochemical noise reduces the
probability that an infected cell adopts the latent state, (3)
the effects of the innate immune response enhance the HIV
latency state, (4) the conditions of the cell before infection
affect the latent phenotype, i.e., the existing expression of
cell restriction factors propitiates HIV latency, and existing
expression of HIV proteins reduces HIV latency.
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Project description:Host protein folding stress responses can play important roles in RNA virus replication and evolution. Intriguingly, prior work revealed a complicated interplay between the cytosolic proteostasis stress response, controlled by its master regulator heat shock factor 1 (HSF1) and human immunodeficiency virus-1 (HIV-1). We sought to isolate HSF1 transcription factor activity from proteostasis stress and elucidate the function of HSF1 in HIV-1 lifecycle in absence of cellular stress. We used chemical genetic, stress-independent control of HSF1 activity to establish whether and how HSF1 influences HIV-1 replication. Stress-independent HSF1 induction decreased both the total quantity and infectivity of HIV-1 virions. Moreover, HIV-1 was unable to escape HSF1-mediated restriction over the course of several serial passages. These results promote continued consideration of the heat shock response as a potential target for antiviral drugs.