WorldWideScience

Sample records for apobec3g drives hiv-1

  1. Human APOBEC3G drives HIV-1 evolution and the development of drug resistance

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Tamoy [Los Alamos National Laboratory; Kim, Eun - Young [FEINBERG SCHOOL OF MEDS; Koning, Fransje [KING' S COLLEGE LONDON; Malim, Michael [KING' S COLLEGE LONDON; Wolinsky, Steven M [FEINBERG SCHOOL OF MEDS

    2008-01-01

    Human APOBEC3G (hA3G) is an innate virus restriction factor that induces deamination of specific cytidine residues in single-stranded human immunodeficiency virus type 1 (HIV-1) DNA. Whereas destructive hA3G editing leads to a profound loss of HIV-1 infectivity, more limited editing could be a source of adaptation and diversification. Here we show that the presence of hA3G in T-cells can drive the development of diversity in HIV-1 populations and that under selection pressure imposed by the nucleotide analog reverse transcriptase inhibitor 3TC ((-)2',3'-dideoxy-3'-thiacytidine), a single point mutation that confers 3TC resistance, methionine 184 to isoleucine (M1841), emerges rapidly and reaches fixation. These results provide strong evidence that mutation by hA3G is an important source of genetic variation on which natural selection acts to shape the structure of the viral population and drive the tempo of HIV-1 evolution.

  2. APOBEC3G-UBA2 fusion as a potential strategy for stable expression of APOBEC3G and inhibition of HIV-1 replication

    Directory of Open Access Journals (Sweden)

    Li Lin

    2008-08-01

    Full Text Available Abstract Background Although APOBEC3G protein is a potent and innate anti-HIV-1 cellular factor, HIV-1 Vif counteracts the effect of APOBEC3G by promoting its degradation through proteasome-mediated proteolysis. Thus, any means that could prevent APOBEC3G degradation could potentially enhance its anti-viral effect. The UBA2 domain has been identified as an intrinsic stabilization signal that protects protein from proteasomal degradation. In this pilot study, we tested whether APOBEC3G, when it is fused with UBA2, can resist Vif-mediated proteasomal degradation and further inhibit HIV-1 infection. Results APOBEC3G-UBA2 fusion protein is indeed more resistant to Vif-mediated degradation than APOBEC3G. The ability of UBA2 domain to stabilize APOBEC3G was diminished when polyubiquitin was over-expressed and the APOBEC3G-UBA2 fusion protein was found to bind less polyubiquitin than APOBEC3G, suggesting that UBA2 stabilizes APOBEC3G by preventing ubiquitin chain elongation and proteasome-mediated proteolysis. Consistently, treatment of cells with a proteasome inhibitor MG132 alleviated protein degradation of APOBEC3G and APOBEC3G-UBA2 fusion proteins. Analysis of the effect of APOBEC3G-UBA2 fusion protein on viral infectivity indicated that infection of virus packaged from HEK293 cells expressing APOBEC3G-UBA2 fusion protein is significantly lower than those packaged from HEK293 cells over-producing APOBEC3G or APOBEC3G-UBA2 mutant fusion proteins. Conclusion Fusion of UBA2 to APOBEC3G can make it more difficult to be degraded by proteasome. Thus, UBA2 could potentially be used to antagonize Vif-mediated APOBEC3G degradation by preventing polyubiquitination. The stabilized APOBEC3G-UBA2 fusion protein gives stronger inhibitory effect on viral infectivity than APOBEC3G without UBA2.

  3. Identification of an HIV-1 replication inhibitor which rescues host restriction factor APOBEC3G in Vif-APOBEC3G complex.

    Science.gov (United States)

    Zhang, Shaoyang; Zhong, Limei; Chen, Bing; Pan, Ting; Zhang, Xue; Liang, Liting; Li, Qianwen; Zhang, Ziying; Chen, Hui; Zhou, Jie; Luo, Haihua; Zhang, Hui; Bai, Chuan

    2015-10-01

    HIV-1 Vif protein is one of the most crucial accessory proteins for viral replication. It efficiently counteracts the important host restriction factor APOBEC3G (apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G, A3G) which is lethal to HIV-1 by causing G to A mutation of viral genome. Vif protein mediates degradation of APOBEC3G via the complicated protein-protein interactions of Vif, APOBEC3G, Elongin C/B and Cullin 5. The importance of Vif-APOBEC3G complex makes it a good potential target to develop new therapeutics of HIV-1. We identified a potent HIV-1 replication inhibitor (ZBMA-1, IC50 = 1.01 μM) that efficiently protected APOBEC3G protein by targeting Vif-APOBEC3G complex. The co-immunoprecipitation and docking studies indicated that compound ZBMA-1 affected the binding of Elongin C with Vif protein.

  4. APOBEC3G inhibits elongation of HIV-1 reverse transcripts.

    Directory of Open Access Journals (Sweden)

    Kate N Bishop

    2008-12-01

    Full Text Available APOBEC3G (A3G is a host cytidine deaminase that, in the absence of Vif, restricts HIV-1 replication and reduces the amount of viral DNA that accumulates in cells. Initial studies determined that A3G induces extensive mutation of nascent HIV-1 cDNA during reverse transcription. It has been proposed that this triggers the degradation of the viral DNA, but there is now mounting evidence that this mechanism may not be correct. Here, we use a natural endogenous reverse transcriptase assay to show that, in cell-free virus particles, A3G is able to inhibit HIV-1 cDNA accumulation not only in the absence of hypermutation but also without the apparent need for any target cell factors. We find that although reverse transcription initiates in the presence of A3G, elongation of the cDNA product is impeded. These data support the model that A3G reduces HIV-1 cDNA levels by inhibiting synthesis rather than by inducing degradation.

  5. Estimating the fraction of progeny virions that must incorporate APOBEC3G for suppression of productive HIV-1 infection

    Energy Technology Data Exchange (ETDEWEB)

    Thangavelu, Pulari U.; Gupta, Vipul; Dixit, Narendra M., E-mail: narendra@chemeng.iisc.ernet.in

    2014-01-20

    The contest between the host factor APOBEC3G (A3G) and the HIV-1 protein Vif presents an attractive target of intervention. The extent to which the A3G–Vif interaction must be suppressed to tilt the balance in favor of A3G remains unknown. We employed stochastic simulations and mathematical modeling of the within-host dynamics and evolution of HIV-1 to estimate the fraction of progeny virions that must incorporate A3G to render productive infection unsustainable. Using three different approaches, we found consistently that a transition from sustained infection to suppression of productive infection occurred when the latter fraction exceeded ∼0.8. The transition was triggered by A3G-induced hypermutations that led to premature stop codons compromising viral production and was consistent with driving the basic reproductive number, R{sub 0}, below unity. The fraction identified may serve as a quantitative guideline for strategies targeting the A3G–Vif axis. - Highlights: • We perform simulations and mathematical modeling of the role of APOBEC3G in suppressing HIV-1 infection. • In three distinct ways, we estimate that when over 80% of progeny virions carry APOBEC3G, productive HIV-1 infection would be suppressed. • Our estimate of this critical fraction presents quantitative guidelines for strategies targeting the APOBEC3G–Vif axis.

  6. Differences in APOBEC3G expression in CD4+ T helper lymphocyte subtypes modulate HIV-1 infectivity.

    Directory of Open Access Journals (Sweden)

    Michael L Vetter

    2009-02-01

    Full Text Available The cytidine deaminases APOBEC3G and APOBEC3F exert anti-HIV-1 activity that is countered by the HIV-1 vif protein. Based on potential transcription factor binding sites in their putative promoters, we hypothesized that expression of APOBEC3G and APOBEC3F would vary with T helper lymphocyte differentiation. Naive CD4+ T lymphocytes were differentiated to T helper type 1 (Th1 and 2 (Th2 effector cells by expression of transcription factors Tbet and GATA3, respectively, as well as by cytokine polarization. APOBEC3G and APOBEC3F RNA levels, and APOBEC3G protein levels, were higher in Th1 than in Th2 cells. T cell receptor stimulation further increased APOBEC3G and APOBEC3F expression in Tbet- and control-transduced, but not in GATA3-transduced, cells. Neutralizing anti-interferon-gamma antibodies reduced both basal and T cell receptor-stimulated APOBEC3G and APOBEC3F expression in Tbet- and control-transduced cells. HIV-1 produced from Th1 cells had more virion APOBEC3G, and decreased infectivity, compared to virions produced from Th2 cells. These differences between Th1- and Th2-produced virions were greater for viruses lacking functional vif, but also seen with vif-positive viruses. Over-expression of APOBEC3G in Th2 cells decreased the infectivity of virions produced from Th2 cells, and reduction of APOBEC3G in Th1 cells increased infectivity of virions produced from Th1 cells, consistent with a causal role for APOBEC3G in the infectivity difference. These results indicate that APOBEC3G and APOBEC3F levels vary physiologically during CD4+ T lymphocyte differentiation, that interferon-gamma contributes to this modulation, and that this physiological regulation can cause changes in infectivity of progeny virions, even in the presence of HIV-1 vif.

  7. Prokaryotic Expression and Purification of HIV-1 Vif and hAPOBEC3G, Preparation of Polyclonal Antibodies

    Institute of Scientific and Technical Information of China (English)

    Lan LI; Yi-shu YANG; Ze-lin LI; Yi ZENG

    2008-01-01

    To prepare HIV-1 Vif and hAPOBEC3G and to produce their antibodies, the full length gene fragment of HIV-1 Vif was amplified by PCR from a plasmid of HIV-1 NL4.3 cDNA, and the APOBEC3G gene was obtained by RT-PCR from the total RNA of H9 cells. The resulting DNA construct was cloned into a prokaryotic expression vector (pET-32a). Recombinant pET-vif and pET-APOBEC3G were expressed respectively in Eserichia coli BL21 (DE3) as an insoluble protein. The vector also contained a six-histidine tag at the C-terminus for convenient purification and detection. To express and purify the HIV-1 Vif and hAPOBEC3G in E. coli cells, the accuracy of inserted gene and specificity of proteins were detected by the two enzyme digestion method, SDS-PAGE, and Western blotting. Rabbits were then immunized by Vif or APOBEC3G protein and serum samples were tested by indirect ELISA to determine the level of antibodies. Immunoenzyme and immunofluorescence assays were performed to identify the specificity of polyclonal antibodies. The titer of the anti-Vif antibodies was 1:204800, and that of the anti-APOBEC3G antibodies was 1:102400. Thus the antibodies could detect the antigen expression in the cells, demonstrating that fusion proteins with high purity and their corresponding polyclonal antibodies with high titer and specificity were achieved.

  8. HIV-1 viral infectivity factor (Vif) alters processive single-stranded DNA scanning of the retroviral restriction factor APOBEC3G.

    Science.gov (United States)

    Feng, Yuqing; Love, Robin P; Chelico, Linda

    2013-03-01

    APOBEC3G is a retroviral restriction factor that can inhibit the replication of human immunodeficiency virus, type 1 (HIV-1) in the absence of the viral infectivity factor (Vif) protein. Virion-encapsidated APOBEC3G can deaminate cytosine to uracil in viral (-)DNA, which leads to hypermutation and inactivation of the provirus. APOBEC3G catalyzes these deaminations processively on single-stranded DNA using sliding and jumping movements. Vif is thought to primarily overcome APOBEC3G through an interaction that mediates APOBEC3G ubiquitination and results in its proteasomal degradation. However, Vif may also inhibit APOBEC3G mRNA translation, virion encapsidation, and deamination activity. Here we investigated the molecular mechanism of VifIIIB- and VifHXB2-mediated inhibition of APOBEC3G deamination activity. Biochemical assays using a model HIV-1 replication assay and synthetic single-stranded or partially double-stranded DNA substrates demonstrated that APOBEC3G has an altered processive mechanism in the presence of Vif. Specifically, VifHXB2 inhibited the jumping and VifIIIB inhibited the sliding movements of APOBEC3G. The absence of such an effect by Vif on degradation-resistant APOBEC3G D128K indicates that a Vif-APOBEC3G interaction mediates this effect. That the partially processive APOBEC3G was less effective at inducing mutagenesis in a model HIV-1 replication assay suggests that Vif co-encapsidation with APOBEC3G can promote sublethal mutagenesis of HIV-1 proviral DNA.

  9. APOBEC3G-depleted resting CD4+ T cells remain refractory to HIV1 infection.

    Directory of Open Access Journals (Sweden)

    Francesca R Santoni de Sio

    Full Text Available BACKGROUND: CD4+ T lymphocytes are the primary targets of HIV1 but cannot be infected when fully quiescent, due to a post-entry block preventing the completion of reverse transcription. Chiu et al. recently proposed that this restriction reflects the action of APOBEC3G (A3G. They further suggested that T cell activation abrogates the A3G-mediated block by directing this protein to a high molecular mass complex. METHODOLOGY/PRINCIPAL FINDINGS: In the present work, we sought to explore further this model. However, we found that effective suppression of A3G by combined RNA interference and expression of HIV1 Vif does not relieve the restrictive phenotype of post-activation resting T cells. We also failed to find a correlation between HIV resistance and the presence of A3G in a low molecular complex in primary T cells. CONCLUSIONS/SIGNIFICANCE: We conclude that A3G is unlikely to play a role in the HIV restrictive phenotype of quiescent T lymphocytes.

  10. Reassessing APOBEC3G Inhibition by HIV-1 Vif-Derived Peptides.

    Science.gov (United States)

    Richards, Christopher M; Li, Ming; Perkins, Angela L; Rathore, Anurag; Harki, Daniel A; Harris, Reuben S

    2017-01-06

    The human APOBEC3G (A3G) enzyme restricts HIV-1 in the absence of the viral accessory protein viral infectivity factor (Vif) by deaminating viral cDNA cytosines to uracils. These uracil lesions base-pair with adenines during the completion of reverse transcription and result in A3G signature G-to-A mutations in the viral genome. Vif protects HIV-1 from A3G-mediated restriction by forming an E3-ubiquitin ligase complex to polyubiquitinate A3G and trigger its degradation. Prior studies indicated that Vif may also directly block the enzymatic activity of A3G and, provocatively, that Vif-derived peptides, Vif 25-39 and Vif 105-119, are similarly inhibitory. Here, we show that Vif 25-39 does not inhibit A3G enzymatic activity and that the inhibitory effect of Vif 105-119 and that of a shorter derivative Vif 107-115, although recapitulated, are non-specific. We also elaborate a simple method for assaying DNA cytosine deaminase activity that eliminates potential polymerase chain reaction-induced biases. Our results show that these Vif-derived peptides are unlikely to be useful as tools to study A3G function or as leads for the development of future therapeutics.

  11. APOBEC3G impairs the multimerization of the HIV-1 Vif protein in living cells.

    Science.gov (United States)

    Batisse, Julien; Guerrero, Santiago Xavier; Bernacchi, Serena; Richert, Ludovic; Godet, Julien; Goldschmidt, Valérie; Mély, Yves; Marquet, Roland; de Rocquigny, Hugues; Paillart, Jean-Christophe

    2013-06-01

    The HIV-1 viral infectivity factor (Vif) is a small basic protein essential for viral fitness and pathogenicity. Vif allows productive infection in nonpermissive cells, including most natural HIV-1 target cells, by counteracting the cellular cytosine deaminases APOBEC3G (apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G [A3G]) and A3F. Vif is also associated with the viral assembly complex and packaged into viral particles through interactions with the viral genomic RNA and the nucleocapsid domain of Pr55(Gag). Recently, we showed that oligomerization of Vif into high-molecular-mass complexes induces Vif folding and influences its binding to high-affinity RNA binding sites present in the HIV genomic RNA. To get further insight into the role of Vif multimerization in viral assembly and A3G repression, we used fluorescence lifetime imaging microscopy (FLIM)- and fluorescence resonance energy transfer (FRET)-based assays to investigate Vif-Vif interactions in living cells. By using two N-terminally tagged Vif proteins, we show that Vif-Vif interactions occur in living cells. This oligomerization is strongly reduced when the putative Vif multimerization domain ((161)PPLP(164)) is mutated, indicating that this domain is crucial, but that regions outside this motif also participate in Vif oligomerization. When coexpressed together with Pr55(Gag), Vif is largely relocated to the cell membrane, where Vif oligomerization also occurs. Interestingly, wild-type A3G strongly interferes with Vif multimerization, contrary to an A3G mutant that does not bind to Vif. These findings confirm that Vif oligomerization occurs in living cells partly through its C-terminal motif and suggest that A3G may target and perturb the Vif oligomerization state to limit its functions in the cell.

  12. HIV-1 Vif Protein Mediates the Degradation of APOBEC3G in Fission Yeast When Over-expressed Using Codon Optimization

    Institute of Scientific and Technical Information of China (English)

    Lin LI; Jing-yun LI; Hong-shuai SUI; Richard Y. Zhao; Yong-jian LIU; Zuo-yi BAO; Si-yang LIU; Dao-min ZHUANG

    2008-01-01

    Interaction between the HIV-1 Vif protein and the cellular host APOBEC3G protein is a promising target for inhibition of HIV-1 replication. Considering that human cells are a very complicated environment for the study of protein interactions, the goal of this study was to check whether fission yeast could be used as a model cell for studying the Vif-APOBEC3G interaction. Vif and APOBEC3G were expressed in fusion with GFP protein in the S. pombe SP223 strain. Subcellular localizations of Vif and APOBEC3G were observed with fluorescent microscopy. Codon optimization was used to over express the Vif protein in S. pombe cells. The degradation of APOBEC3G mediated by Vif was tested through expressing Vif and GFP-APOBEC3G proteins in the same cell. Western Blot analysis was used to measure the corresponding protein levels under different experimental conditions. The results showed that the Vif protein was predominantly localized in the nucleus of S.pombe cells, APOBEC3G was localized in the cytoplasm and concentrated at punctate bodies that were often in close proximity to the nucleus but were not necessarily restricted from other regions in the cytoplasm. Vif protein expression levels were increased significantly by using codon optimization and APOBEC3G was degraded when Vif was over-expressed in the same S. pombe cells. These results indicate that fission yeast is a good model for studying the interaction between the Vif and APOBEC3G proteins.

  13. Intracellular interactions between APOBEC3G, RNA, and HIV-1 Gag: APOBEC3G multimerization is dependent on its association with RNA

    Directory of Open Access Journals (Sweden)

    Friew Yeshitila N

    2009-06-01

    Full Text Available Abstract Background Host restriction factor APOBEC3G (A3G blocks human immunodeficiency virus type 1 (HIV-1 replication by G-to-A hypermutation, and by inhibiting DNA synthesis and provirus formation. Previous reports have suggested that A3G is a dimer and its virion incorporation is mediated through interactions with viral or nonviral RNAs and/or HIV-1 Gag. We have now employed a bimolecular fluorescence complementation assay (BiFC to analyze the intracellular A3G-A3G, A3G-RNA, and A3G-Gag interactions in living cells by reconstitution of yellow fluorescent protein (YFP from its N- or C-terminal fragments. Results The results obtained with catalytic domain 1 and 2 (CD1 and CD2 mutants indicate that A3G-A3G and A3G-Gag multimerization is dependent on an intact CD1 domain, which is required for RNA binding. A mutant HIV-1 Gag that exhibits reduced RNA binding also failed to reconstitute BiFC with wild-type A3G, indicating a requirement for both HIV-1 Gag and A3G to bind to RNA for their multimerization. Addition of a non-specific RNA binding peptide (P22 to the N-terminus of a CD1 mutant of A3G restored BiFC and virion incorporation, but failed to inhibit viral replication, indicating that the mutations in CD1 resulted in additional defects that interfere with A3G's antiviral activity. Conclusion These studies establish a robust BiFC assay for analysis of intracellular interactions of A3G with other macromolecules. The results indicate that in vivo A3G is a monomer that forms multimers upon binding to RNA. In addition, we observed weak interactions between wild-type A3G molecules and RNA binding-defective mutants of A3G, which could explain previously described protein-protein interactions between purified A3G molecules.

  14. APOBEC3G and APOBEC3F require an endogenous cofactor to block HIV-1 replication.

    Directory of Open Access Journals (Sweden)

    Yanxing Han

    2008-07-01

    Full Text Available APOBEC3G (A3G/APOBEC3F (A3F are two members of APOBEC3 cytidine deaminase subfamily. Although they potently inhibit the replication of vif-deficient HIV-1, this mechanism is still poorly understood. Initially, A3G/A3F were thought to catalyze C-to-U transitions on the minus-strand viral cDNAs during reverse transcription to disrupt the viral life cycle. Recently, it was found more likely that A3G/A3F directly interrupts viral reverse transcription or integration. In addition, A3G/A3F are both found in the high-molecular-mass complex in immortalized cell lines, where they interact with a number of different cellular proteins. However, there has been no evidence to prove that these interactions are required for A3G/A3F function. Here, we studied A3G/A3F-restricted HIV-1 replication in six different human T cell lines by infecting them with wild-type or vif-deficient HIV-1. Interestingly, in a CEM-derived cell line CEM-T4, which expresses high levels of A3G/A3F proteins, the vif-deficient virus replicated as equally well as the wild-type virus, suggesting that these endogenous antiretroviral genes lost anti-HIV activities. It was confirmed that these A3G/A3F genes do not contain any mutation and are functionally normal. Consistently, overexpression of exogenous A3G/A3F in CEM-T4 cells still failed to restore their anti-HIV activities. However, this activity could be restored if CEM-T4 cells were fused to 293T cells to form heterokaryons. These results demonstrate that CEM-T4 cells lack a cellular cofactor, which is critical for A3G/A3F anti-HIV activity. We propose that a further study of this novel factor will provide another strategy for a complete understanding of the A3G/A3F antiretroviral mechanism.

  15. Natural variation in Vif: differential impact on APOBEC3G/3F and a potential role in HIV-1 diversification.

    Directory of Open Access Journals (Sweden)

    Viviana Simon

    2005-09-01

    Full Text Available The HIV-1 Vif protein counteracts the antiviral activity exhibited by the host cytidine deaminases APOBEC3G and APOBEC3F. Here, we show that defective vif alleles can readily be found in HIV-1 isolates and infected patients. Single residue changes in the Vif protein sequence are sufficient to cause the loss of Vif-induced APOBEC3 neutralization. Interestingly, not all the detected defects lead to a complete inactivation of Vif function since some mutants retained selective neutralizing activity against APOBEC3F but not APOBEC3G or vice versa. Concordantly, independently hypermutated proviruses with distinguishable patterns of G-to-A substitution attributable to cytidine deamination induced by APOBEC3G, APOBEC3F, or both enzymes were present in individuals carrying proviruses with completely or partly defective Vif variants. Natural variation in Vif function may result in selective and partial neutralization of cytidine deaminases and thereby promote viral sequence diversification within HIV-1 infected individuals.

  16. Natural Variation in Vif: Differential Impact on APOBEC3G/3F and a Potential Role in HIV-1 Diversification.

    Directory of Open Access Journals (Sweden)

    2005-09-01

    Full Text Available The HIV-1 Vif protein counteracts the antiviral activity exhibited by the host cytidine deaminases APOBEC3G and APOBEC3F. Here, we show that defective vif alleles can readily be found in HIV-1 isolates and infected patients. Single residue changes in the Vif protein sequence are sufficient to cause the loss of Vif-induced APOBEC3 neutralization. Interestingly, not all the detected defects lead to a complete inactivation of Vif function since some mutants retained selective neutralizing activity against APOBEC3F but not APOBEC3G or vice versa. Concordantly, independently hypermutated proviruses with distinguishable patterns of G-to-A substitution attributable to cytidine deamination induced by APOBEC3G, APOBEC3F, or both enzymes were present in individuals carrying proviruses with completely or partly defective Vif variants. Natural variation in Vif function may result in selective and partial neutralization of cytidine deaminases and thereby promote viral sequence diversification within HIV-1 infected individuals.

  17. Association of single nucleotide polymorphisms of APOBEC3G with susceptibility to HIV-1 infection and disease progression among men engaging in homosexual activity in northern China.

    Science.gov (United States)

    Li, Qiuyan; Qiao, Yuandong; Zhang, Guangfa; He, Ning; Zhang, Xuelong; Jia, Xueyuan; Sun, Haiming; Wang, Chuntao; Xu, Lidan

    2017-01-01

    Men who have sex with men (MSM) are at high risk of HIV infection. The APOBEC3G (apolipoprotein B mRNA editing catalytic polypeptide 3G) protein is a component of innate antiviral immunity that inhibits HIV-1 replication. In the present study, a total of 483 HIV-1 seropositive men and 493 HIV-1 seronegative men were selected to investigate the association between single nucleotide polymorphisms (SNPs) of the APOBEC3G gene and susceptibility to HIV-1 infection and AIDS progression among MSM residing in northern China. Genotyping of four SNPs (rs5757465, rs3736685, rs8177832, and rs2899313) of the APOBEC3G was performed using the SNPscan™ Kit, while the rs2294367 polymorphism was genotyped using the SNaPshot multiplex system. Our results disclosed no association between the SNPs of APOBEC3G and susceptibility to HIV-1, or effects of these polymorphisms on the CD4(+) T cell count or clinical phase of disease. A meta-analysis of 1624 men with HIV-1 infection and 1523 controls suggested that the association between rs8177832 and susceptibility was not significant. However, we observed a trend towards association with HIV-1 infection for haplotype TTACA (p = 0.082). The potential role of variants of APOBEC3G in HIV-1/AIDS warrants further investigation.

  18. A naturally occurring Vif mutant (I107T) attenuates anti-APOBEC3G activity and HIV-1 replication.

    Science.gov (United States)

    Peng, Jinyu; Ao, Zhujun; Matthews, Chris; Wang, Xiaoxia; Ramdahin, Sue; Chen, Xi; Li, Junhua; Chen, Liyu; He, Jianmei; Ball, Blake; Fowke, Keith; Plummer, Frank; Embree, Joanne; Yao, Xiaojian

    2013-08-23

    The human immunodeficiency virus type 1 (HIV-1) Vif protein counteracts the antiviral activity of the apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3 (APOBEC3) family of proteins by targeting the proteins for degradation through the ubiquitin-proteasome pathway. Previous mutagenic studies have shown that multiple domains of Vif are required for interacting with APOBEC3G proteins and the proteasome pathway. However, very few mutagenesis and functional analyses of patient-derived Vif proteins have been conducted. In this study, we amplified and cloned the HIV-1 vif genes from the peripheral blood mononuclear cells (PBMCs) of five HIV-1-infected individuals in Nairobi and further tested the impact of the genes on anti-A3G activity and HIV-1 replication. The gene sequence analysis revealed high genetic variation of vif genes from different HIV-1-infected individuals. Interestingly, the Vif proteins derived from two of the three long-term survivors (LTSs) displayed a significantly impaired ability to mediate the degradation of A3G. In particular, a single amino acid change (I107T) in one of the non-functional LTS Vif variants, which has not been previously identified in the Los Alamos databases of vif sequences, was found to be responsible for the lack of anti-A3G activity. Further study demonstrated that HIV-1 carrying an I107T Vif mutation displayed significantly reduced fitness in A3G(+) T cells and PBMCs. Moreover, co-infecting A3G(+) T cells with both the wild-type and I107T Vif viruses resulted in decreased viral replication. Overall, the results of this study indicate that the HIV-1 Vif residue I107 is important for its anti-APOBEC3G activity and viral replication, which may have implications for viral fitness in vivo.

  19. Different mutagenic potential of HIV-1 restriction factors APOBEC3G and APOBEC3F is determined by distinct single-stranded DNA scanning mechanisms.

    Directory of Open Access Journals (Sweden)

    Anjuman Ara

    2014-03-01

    Full Text Available The APOBEC3 deoxycytidine deaminase family functions as host restriction factors that can block replication of Vif (virus infectivity factor deficient HIV-1 virions to differing degrees by deaminating cytosines to uracils in single-stranded (-HIV-1 DNA. Upon replication of the (-DNA to (+DNA, the HIV-1 reverse transcriptase incorporates adenines opposite the uracils, thereby inducing C/G→T/A mutations that can functionally inactivate HIV-1. Although both APOBEC3F and APOBEC3G are expressed in cell types HIV-1 infects and are suppressed by Vif, there has been no prior biochemical analysis of APOBEC3F, in contrast to APOBEC3G. Using synthetic DNA substrates, we characterized APOBEC3F and found that similar to APOBEC3G; it is a processive enzyme and can deaminate at least two cytosines in a single enzyme-substrate encounter. However, APOBEC3F scanning movement is distinct from APOBEC3G, and relies on jumping rather than both jumping and sliding. APOBEC3F jumping movements were also different from APOBEC3G. The lack of sliding movement from APOBEC3F is due to an ¹⁹⁰NPM¹⁹² motif, since insertion of this motif into APOBEC3G decreases its sliding movements. The APOBEC3G NPM mutant induced significantly less mutations in comparison to wild-type APOBEC3G in an in vitro model HIV-1 replication assay and single-cycle infectivity assay, indicating that differences in DNA scanning were relevant to restriction of HIV-1. Conversely, mutation of the APOBEC3F ¹⁹¹Pro to ¹⁹¹Gly enables APOBEC3F sliding movements to occur. Although APOBEC3F ¹⁹⁰NGM¹⁹² could slide, the enzyme did not induce more mutagenesis than wild-type APOBEC3F, demonstrating that the unique jumping mechanism of APOBEC3F abrogates the influence of sliding on mutagenesis. Overall, we demonstrate key differences in the impact of APOBEC3F- and APOBEC3G-induced mutagenesis on HIV-1 that supports a model in which both the processive DNA scanning mechanism and preferred

  20. Identification of the HIV-1 Vif and Human APOBEC3G Protein Interface.

    Science.gov (United States)

    Letko, Michael; Booiman, Thijs; Kootstra, Neeltje; Simon, Viviana; Ooms, Marcel

    2015-12-01

    Human cells express natural antiviral proteins, such as APOBEC3G (A3G), that potently restrict HIV replication. As a counter-defense, HIV encodes the accessory protein Vif, which binds A3G and mediates its proteasomal degradation. Our structural knowledge on how Vif and A3G interact is limited, because a co-structure is not available. We identified specific points of contact between Vif and A3G by using functional assays with full-length A3G, patient-derived Vif variants, and HIV forced evolution. These anchor points were used to model and validate the Vif-A3G interface. The resultant co-structure model shows that the negatively charged β4-α4 A3G loop, which contains primate-specific variation, is the core Vif binding site and forms extensive interactions with a positively charged pocket in HIV Vif. Our data present a functional map of this viral-host interface and open avenues for targeted approaches to block HIV replication by obstructing the Vif-A3G interaction.

  1. ASK1 restores the antiviral activity of APOBEC3G by disrupting HIV-1 Vif-mediated counteraction.

    Science.gov (United States)

    Miyakawa, Kei; Matsunaga, Satoko; Kanou, Kazuhiko; Matsuzawa, Atsushi; Morishita, Ryo; Kudoh, Ayumi; Shindo, Keisuke; Yokoyama, Masaru; Sato, Hironori; Kimura, Hirokazu; Tamura, Tomohiko; Yamamoto, Naoki; Ichijo, Hidenori; Takaori-Kondo, Akifumi; Ryo, Akihide

    2015-04-22

    APOBEC3G (A3G) is an innate antiviral restriction factor that strongly inhibits the replication of human immunodeficiency virus type 1 (HIV-1). An HIV-1 accessory protein, Vif, hijacks the host ubiquitin-proteasome system to execute A3G degradation. Identification of the host pathways that obstruct the action of Vif could provide a new strategy for blocking viral replication. We demonstrate here that the host protein ASK1 (apoptosis signal-regulating kinase 1) interferes with the counteraction by Vif and revitalizes A3G-mediated viral restriction. ASK1 binds the BC-box of Vif, thereby disrupting the assembly of the Vif-ubiquitin ligase complex. Consequently, ASK1 stabilizes A3G and promotes its incorporation into viral particles, ultimately reducing viral infectivity. Furthermore, treatment with the antiretroviral drug AZT (zidovudine) induces ASK1 expression and restores the antiviral activity of A3G in HIV-1-infected cells. This study thus demonstrates a distinct function of ASK1 in restoring the host antiviral system that can be enhanced by AZT treatment.

  2. Pokeweed antiviral protein restores levels of cellular APOBEC3G during HIV-1 infection by depurinating Vif mRNA.

    Science.gov (United States)

    Krivdova, Gabriela; Hudak, Katalin A

    2015-10-01

    Pokeweed antiviral protein (PAP) is an RNA glycosidase that inhibits production of human immunodeficiency virus type 1 (HIV-1) when expressed in human culture cells. Previously, we showed that the expression of PAP reduced the levels of several viral proteins, including virion infectivity factor (Vif). However, the mechanism causing Vif reduction and the consequences of the inhibition were not determined. Here we show that the Vif mRNA is directly depurinated by PAP. Because of depurination at two specific sites within the Vif ORF, Vif levels decrease during infections and the progeny viruses that are generated are ∼ 10-fold less infectious and compromised for proviral integration. These results are consistent with PAP activity inhibiting translation of Vif, which in turn reduces the effect of Vif to inactivate the host restriction factor APOBEC3G (apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like editing complex 3G). Our findings identify Vif mRNA as a new substrate for PAP and demonstrate that derepression of innate immunity against HIV-1 contributes to its antiviral activity.

  3. Identification of a novel HIV-1 inhibitor targeting Vif-dependent degradation of human APOBEC3G protein.

    Science.gov (United States)

    Pery, Erez; Sheehy, Ann; Nebane, N Miranda; Brazier, Andrew Jay; Misra, Vikas; Rajendran, Kottampatty S; Buhrlage, Sara J; Mankowski, Marie K; Rasmussen, Lynn; White, E Lucile; Ptak, Roger G; Gabuzda, Dana

    2015-04-17

    APOBEC3G (A3G) is a cellular cytidine deaminase that restricts HIV-1 replication by inducing G-to-A hypermutation in viral DNA and by deamination-independent mechanisms. HIV-1 Vif binds to A3G, resulting in its degradation via the 26 S proteasome. Therefore, this interaction represents a potential therapeutic target. To identify compounds that inhibit interaction between A3G and HIV-1 Vif in a high throughput format, we developed a homogeneous time-resolved fluorescence resonance energy transfer assay. A 307,520 compound library from the NIH Molecular Libraries Small Molecule Repository was screened. Secondary screens to evaluate dose-response performance and off-target effects, cell-based assays to identify compounds that attenuate Vif-dependent degradation of A3G, and assays testing antiviral activity in peripheral blood mononuclear cells and T cells were employed. One compound, N.41, showed potent antiviral activity in A3G(+) but not in A3G(-) T cells and had an IC50 as low as 8.4 μM and a TC50 of >100 μM when tested against HIV-1Ba-L replication in peripheral blood mononuclear cells. N.41 inhibited the Vif-A3G interaction and increased cellular A3G levels and incorporation of A3G into virions, thereby attenuating virus infectivity in a Vif-dependent manner. N.41 activity was also species- and Vif-dependent. Preliminary structure-activity relationship studies suggest that a hydroxyl moiety located at a phenylamino group is critical for N.41 anti-HIV activity and identified N.41 analogs with better potency (IC50 as low as 4.2 μM). These findings identify a new lead compound that attenuates HIV replication by liberating A3G from Vif regulation and increasing its innate antiviral activity.

  4. APOBEC3G-mediated G-to-A hypermutation of the HIV-1 genome: the missing link in antiviral molecular mechanisms

    Directory of Open Access Journals (Sweden)

    Ayaka Okada

    2016-12-01

    Full Text Available APOBEC3G (A3G is a member of the cellular polynucleotide cytidine deaminases, which catalyze the deamination of cytosine (dC to uracil (dU in single-stranded DNA. These enzymes potently inhibit the replication of a variety of retroviruses and retrotransposons, including HIV-1. A3G is incorporated into vif-deficient HIV-1 virions and targets viral reverse transcripts, particularly minus-stranded DNA products, in newly infected cells. It is well established that the enzymatic activity of A3G is closely correlated with the potential to greatly inhibit HIV-1 replication in the absence of Vif. However, the details of the underlying molecular mechanisms are not fully understood. One potential mechanism of A3G antiviral activity is that the A3G-dependent deamination may trigger degradation of the dU-containing reverse transcripts by cellular uracil DNA glycosylases (UDGs. More recently, another mechanism has been suggested, in which the virion-incorporated A3G generates lethal levels of the G-to-A hypermutation in the viral DNA genome, thus potentially driving the viruses into error catastrophe mode. In this mini review article, we summarize the deaminase-dependent and deaminase-independent molecular mechanisms of A3G and discuss how A3G-mediated deamination is linked to antiviral mechanisms.

  5. Incomplete APOBEC3G/F Neutralization by HIV-1 Vif Mutants Facilitates the Genetic Evolution from CCR5 to CXCR4 Usage.

    Science.gov (United States)

    Alteri, Claudia; Surdo, Matteo; Bellocchi, Maria Concetta; Saccomandi, Patrizia; Continenza, Fabio; Armenia, Daniele; Parrotta, Lucia; Carioti, Luca; Costa, Giosuè; Fourati, Slim; Di Santo, Fabiola; Scutari, Rossana; Barbaliscia, Silvia; Fedele, Valentina; Carta, Stefania; Balestra, Emanuela; Alcaro, Stefano; Marcelin, Anne Genevieve; Calvez, Vincent; Ceccherini-Silberstein, Francesca; Artese, Anna; Perno, Carlo Federico; Svicher, Valentina

    2015-08-01

    Incomplete APOBEC3G/F neutralization by a defective HIV-1Vif protein can promote genetic diversification by inducing G-to-A mutations in the HIV-1 genome. The HIV-1 Env V3 loop, critical for coreceptor usage, contains several putative APOBEC3G/F target sites. Here, we determined if APOBEC3G/F, in the presence of Vif-defective HIV-1 virus, can induce G-to-A mutations at V3 positions critical to modulation of CXCR4 usage. Peripheral blood mononuclear cells (PBMC) and monocyte-derived macrophages (MDM) from 2 HIV-1-negative donors were infected with CCR5-using 81.A-VifWT virus (i.e., with wild-type [WT] Vif protein), 81.A-VifE45G, or 81.A-VifK22E (known to incompletely/partially neutralize APOBEC3G/F). The rate of G-toA mutations was zero or extremely low in 81.A-VifWT- and 81.A-VifE45G-infected PBMC from both donors. Conversely, G-to-A enrichment was detected in 81.A-VifK22E-infected PBMC (prevalence ranging from 2.18% at 7 days postinfection [dpi] to 3.07% at 21 dpi in donor 1 and from 10.49% at 7 dpi to 8.69% at 21 dpi in donor 2). A similar scenario was found in MDM. G-to-A mutations occurred at 8 V3 positions, resulting in nonsynonymous amino acid substitutions. Of them, G24E and E25K strongly correlated with phenotypically/genotypically defined CXCR4-using viruses (P = 0.04 and 5.5e-7, respectively) and increased the CXCR4 N-terminal binding affinity for V3 (WT, -40.1 kcal/mol; G24E, -510 kcal/mol; E25K, -522 kcal/mol). The analysis of paired V3 and Vif DNA sequences from 84 HIV-1-infected patients showed that the presence of a Vif-defective virus correlated with CXCR4 usage in proviral DNA (P = 0.04). In conclusion, incomplete APOBEC3G/F neutralization by a single Vif amino acid substitution seeds a CXCR4-using proviral reservoir. This can have implications for the success of CCR5 antagonist-based therapy, as well as for the risk of disease progression.

  6. Antiviral Warrior-APOBEC3G

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-xia; MA Yi-cai

    2005-01-01

    This paper is to further understand how APOBEC3G can defend the retroviruses and to find new approaches to AIDs (acquired immure deficiency syndrome).The viral infectivity factor (Vif) induces rapid degradation of APOBEC3G by ubiquitination, which is a proteosome-dependent pathway. Precisely speaking, only in the virus-producing cell Vif expression is necessary; in its absence, infection of a subsequent target cell terminates at a postentry step through the action of the human APOBEC3G antiviral mechanism. Vif protein has two domains: one binds to APOBEC3G and the other regulates the degradation of APOBEC3G by a conserved sequence, SLQ (Y/F) LA motif. Recently, the research on Vif has also revealed APOBEC3G is a novel component of innate immune system. In fact, APOBEC3G not only acts in DNA editing to block the replication of retroviruses such as HIV-1, but also is able to defend a wide spectrum of distantly related retroviruses and interferes with HBV through a different mechanism from HIV.

  7. Induction of heat-shock protein 70 by prostaglandin A₁ inhibits HIV-1 Vif-mediated degradation of APOBEC3G.

    Science.gov (United States)

    Sugiyama, Ryuichi; Abe, Makoto; Nishitsuji, Hironori; Murakami, Yuko; Takeuchi, Hiroaki; Takaku, Hiroshi

    2013-09-01

    Previous studies have demonstrated that cyclopentenone prostaglandins (cyPGs) inhibit human immunodeficiency virus type 1 (HIV-1) replication in various cell types. This antiviral activity has been associated with the induction of heat-shock protein 70 (HSP70) in infected cells. We investigated a new role of prostaglandin A₁ (PGA₁) in the replication of HIV-1 in non-permissive cells. Because overexpression of HSP70 blocks the viral infectivity factor (Vif)-mediated degradation of APOBEC3G (A3G) via the ubiquitin-proteasome pathway, we examined the effects of PGA₁ on A3G and HIV-1 replication. The induction of HSP70 synthesis by PGA₁ blocked Vif-mediated A3G degradation and enhanced the incorporation of A3G into both wild-type and Vif-deficient viruses. Furthermore, we determined the viral titer of HIV-1 particles produced from PGA₁-treated 293T cells. The induction of HSP70 synthesis by PGA₁ significantly reduced the viral titer in the presence of A3G. Additionally, the p24 Gag antigen levels were dramatically reduced in non-permissive cells treated once or repeatedly with PGA₁. Thus, we showed that PGA₁ inhibits HIV-1 replication, at least in part, by blocking Vif-mediated A3G degradation.

  8. Human APOBEC3G-mediated hypermutation is associated with antiretroviral therapy failure in HIV-1 subtype C-infected individuals

    Directory of Open Access Journals (Sweden)

    Anita Shet

    2013-02-01

    Full Text Available Introduction: Human APOBEC3G/F (hA3G/F restricts retroviral replication through G-to-A hypermutations, which can generate drug-resistant progenies in vitro. The clinical relevance is still inconclusive. To bridge this gap, we aim to study the role of these hypermutations in evolution of drug resistance; we characterised hA3G/F-mediated hypermutations in the RT region of the pol gene of patients with or without antiretroviral therapy (ART. Methods: In 88 HIV-1-positive individuals, drug resistance genotyping was carried out in plasma virus and provirus by population sequencing. Hypermutations were determined by three different approaches using Hypermut 2.0 software, cluster analysis and APOBEC3G-mediated defectives indices. Clinical and demographic characteristics of these individuals were studied in relation to these hypermutations. Results: hA3G/F-mediated hypermutated sequences in proviral DNA, but not in plasma virus, were identified in 11.4% (10/88 subjects. Proviral hypermutations were observed more frequently in patients with ART failure than in ART-naïve individuals (p=0.03. In therapy failure patients, proviral hypermutation were associated with greater intra-compartmental genetic diversity (p<0.001. In therapy-naïve individuals, hypermutated proviral DNA with M184I and M230I mutations due to the editing of hA3G, had stop codons in the open reading frames and the same mutations were absent in the plasma virus. Only a limited concordance was found between the drug resistance mutations in plasma RNA and proviral DNA. Conclusions: hA3G lethal hypermutation was significantly associated with ART failure in Indian HIV-1 subtype C patients. It is unlikely that viral variants, which exhibit hypermutated sequences and M184I and/or M230I, will mature and expand in vivo.

  9. Vpr14-88-Apobec3G fusion protein is efficiently incorporated into Vif-positive HIV-1 particles and inhibits viral infection.

    Directory of Open Access Journals (Sweden)

    Zhujun Ao

    Full Text Available BACKGROUND: APOBEC3G (A3G, a deoxycytidine deaminase, is a potent host antiviral factor that can restrict HIV-1 infection. During Vif-negative HIV-1 replication, A3G is incorporated into HIV-1 particles, induces mutations in reverse transcribed viral DNA and inhibits reverse transcription. However, HIV-1 Vif counteracts A3G's activities by inducing its degradation and by blocking its incorporation into HIV-1 particles. Thus, it is interesting to elucidate a mechanism that would allow A3G to escape the effects of Vif in order to rescue its potent antiviral activity and to provide a possible novel therapeutic strategy for treating HIV-1 infection. METHODS AND FINDINGS: In this study, we generated an R88-A3G fusion protein by fusing A3G to a virion-targeting polypeptide (R14-88 derived from HIV-1 Vpr protein and compared its antiviral effects relative to those of HA-tagged native A3G (HA-A3G. Our study showed that transient expression of the R88-A3G fusion protein in both Vif(- and Vif(+ HIV-1 producing cells drastically inhibited viral infection in HeLa-CD4-CCR5-cells, CD4(+ C8166 T cells and human primary PBMCs. Moreover, we established CD4(+ C8166 T cell lines that stably express either R88-A3G or HA-A3G by transduction with VSV-G-pseudotyped lentiviral vector that harbor expression cassettes for R88-A3G or HA-A3G, respectively, and tested their susceptibility to Vif(+ HIV-1 infection. Our results clearly reveal that expression of R88-A3G in transduced CD4(+ C8166 cells significantly blocked Vif(+ HIV-1 infection. In an attempt to understand the mechanism underlying the antiviral activity of R88-A3G, we demonstrated that R88-A3G was efficiently incorporated into viral particles in the presence of Vif. Moreover, PCR analysis revealed that R88-A3G significantly inhibited viral cDNA synthesis during the early stage of Vif(+ virus infection. CONCLUSIONS: Our results clearly indicate that R88 delivers A3G into Vif(+ HIV-1 particles and inhibits

  10. Likely role of APOBEC3G-mediated G-to-A mutations in HIV-1 evolution and drug resistance.

    Directory of Open Access Journals (Sweden)

    Patric Jern

    2009-04-01

    Full Text Available The role of APOBEC3 (A3 protein family members in inhibiting retrovirus infection and mobile element retrotransposition is well established. However, the evolutionary effects these restriction factors may have had on active retroviruses such as HIV-1 are less well understood. An HIV-1 variant that has been highly G-to-A mutated is unlikely to be transmitted due to accumulation of deleterious mutations. However, G-to-A mutated hA3G target sequences within which the mutations are the least deleterious are more likely to survive selection pressure. Thus, among hA3G targets in HIV-1, the ratio of nonsynonymous to synonymous changes will increase with virus generations, leaving a footprint of past activity. To study such footprints in HIV-1 evolution, we developed an in silico model based on calculated hA3G target probabilities derived from G-to-A mutation sequence contexts in the literature. We simulated G-to-A changes iteratively in independent sequential HIV-1 infections until a stop codon was introduced into any gene. In addition to our simulation results, we observed higher ratios of nonsynonymous to synonymous mutation at hA3G targets in extant HIV-1 genomes than in their putative ancestral genomes, compared to random controls, implying that moderate levels of A3G-mediated G-to-A mutation have been a factor in HIV-1 evolution. Results from in vitro passaging experiments of HIV-1 modified to be highly susceptible to hA3G mutagenesis verified our simulation accuracy. We also used our simulation to examine the possible role of A3G-induced mutations in the origin of drug resistance. We found that hA3G activity could have been responsible for only a small increase in mutations at known drug resistance sites and propose that concerns for increased resistance to other antiviral drugs should not prevent Vif from being considered a suitable target for development of new drugs.

  11. Translational regulation of APOBEC3G mRNA by Vif requires its 5'UTR and contributes to restoring HIV-1 infectivity.

    Science.gov (United States)

    Guerrero, Santiago; Libre, Camille; Batisse, Julien; Mercenne, Gaëlle; Richer, Delphine; Laumond, Géraldine; Decoville, Thomas; Moog, Christiane; Marquet, Roland; Paillart, Jean-Christophe

    2016-12-20

    The essential HIV-1 viral infectivity factor (Vif) allows productive infection of non-permissive cells expressing cytidine deaminases APOBEC3G (A3G) and A3F by decreasing their cellular level, and preventing their incorporation into virions. Unlike the Vif-induced degradation of A3G, the functional role of the inhibition of A3G translation by Vif remained unclear. Here, we show that two stem-loop structures within the 5'-untranslated region of A3G mRNA are crucial for translation inhibition by Vif in cells, and most Vif alleles neutralize A3G translation efficiently. Interestingly, K26R mutation in Vif abolishes degradation of A3G by the proteasome but has no effect at the translational level, indicating these two pathways are independent. These two mechanisms, proteasomal degradation and translational inhibition, similarly contribute to decrease the cellular level of A3G by Vif and to prevent its incorporation into virions. Importantly, inhibition of A3G translation is sufficient to partially restore viral infectivity in the absence of proteosomal degradation. These findings demonstrate that HIV-1 has evolved redundant mechanisms to specifically inhibit the potent antiviral activity of A3G.

  12. An analog of camptothecin inactive against Topoisomerase I is broadly neutralizing of HIV-1 through inhibition of Vif-dependent APOBEC3G degradation.

    Science.gov (United States)

    Bennett, Ryan P; Stewart, Ryan A; Hogan, Priscilla A; Ptak, Roger G; Mankowski, Marie K; Hartman, Tracy L; Buckheit, Robert W; Snyder, Beth A; Salter, Jason D; Morales, Guillermo A; Smith, Harold C

    2016-12-01

    Camptothecin (CPT) is a natural product discovered to be active against various cancers through its ability to inhibit Topoisomerase I (TOP1). CPT analogs also have anti-HIV-1 (HIV) activity that was previously shown to be independent of TOP1 inhibition. We show that a cancer inactive CPT analog (O2-16) inhibits HIV infection by disrupting multimerization of the HIV protein Vif. Antiviral activity depended on the expression of the cellular viral restriction factor APOBEC3G (A3G) that, in the absence of functional Vif, has the ability to hypermutate HIV proviral DNA during reverse transcription. Our studies demonstrate that O2-16 has low cytotoxicity and inhibits Vif-dependent A3G degradation, enabling A3G packaging into HIV viral particles that results in A3G signature hypermutations in viral genomes. This antiviral activity was A3G-dependent and broadly neutralizing against sixteen HIV clinical isolates from groups M (subtypes A-G), N, and O as well as seven single and multi-drug resistant strains of HIV. Molecular modeling predicted binding near the PPLP motif crucial for Vif multimerization and activity. O2-16 also was active in blocking Vif degradation of APOBEC3F (A3F). We propose that CPT analogs not active against TOP1 have novel therapeutic potential as Vif antagonists that enable A3G-dependent hypermutation of HIV.

  13. Differential Contributions of Ubiquitin-Modified APOBEC3G Lysine Residues to HIV-1 Vif-Induced Degradation.

    Science.gov (United States)

    Turner, Tiffany; Shao, Qiujia; Wang, Weiran; Wang, Yudi; Wang, Chenliang; Kinlock, Ballington; Liu, Bindong

    2016-08-28

    Apolipoprotein B mRNA-editing enzyme-catalytic polypeptide-like 3G (A3G) is a host restriction factor that impedes HIV-1 replication. Viral integrity is salvaged by HIV-1 virion infectivity factor (Vif), which mediates A3G polyubiquitination and subsequent cellular depletion. Previous studies have implied that A3G polyubiquitination is essential for Vif-induced degradation. However, the contribution of polyubiquitination to the rate of A3G degradation remains unclear. Here, we show that A3G polyubiquitination is essential for degradation. Inhibition of ubiquitin-activating enzyme E1 by PYR-41 or blocking the formation of ubiquitin chains by over-expressing the lysine to arginine mutation of ubiquitin K48 (K48R) inhibited A3G degradation. Our A3G mutagenesis study showed that lysine residues 297, 301, 303, and 334 were not sufficient to render lysine-free A3G sensitive to Vif-mediated degradation. Our data also confirm that Vif could induce ubiquitin chain formation on lysine residues interspersed throughout A3G. Notably, A3G degradation relied on the lysine residues involved in polyubiquitination. Although A3G and the A3G C-terminal mutant interacted with Vif and were modified by ubiquitin chains, the latter remained more resistant to Vif-induced degradation. Furthermore, the A3G C-terminal mutant, but not the N-terminal mutant, maintained potent antiviral activity in the presence of Vif. Taken together, our results suggest that the location of A3G ubiquitin modification is a determinant for Vif-mediated degradation, implying that in addition to polyubiquitination, other factors may play a key role in the rate of A3G degradation.

  14. HIV-1 Gag-virus-like particles inhibit HIV-1 replication in dendritic cells and T cells through IFN-α-dependent upregulation of APOBEC3G and 3F.

    Science.gov (United States)

    Chang, Myint Oo; Suzuki, Tomoyuki; Yamamoto, Norio; Watanabe, Megumi; Takaku, Hiroshi

    2012-01-01

    Human immunodeficiency virus-1 (HIV-1) infection and the acquired immune deficiency syndrome (AIDS) pandemic remain global threats in the absence of a protective or a therapeutic vaccine. HIV-1 replication is reportedly inhibited by some cellular factors, including APOBEC3G (A3G) and APOBEC3F (A3F), which are well known inhibitors of HIV-1. Recently, HIV-1 Gag-virus-like particles (Gag-VLPs) have been shown to be safe and potent HIV-1 vaccine candidates that can elicit strong cellular and humoral immunity without need of any adjuvant. In this report, we stimulated human monocyte-derived dendritic cells (DCs) with Gag-VLPs and we demonstrated that Gag-VLP-treated DCs (VLP-DCs) produced interferon alpha (IFN-α), along with an increase in mRNA and protein expression of A3G and A3F. Gag-VLPs inhibited HIV-1 replication not only in DCs themselves, but also in cocultured T cells in an IFN-α-dependent manner. In addition, A3G/3F content in HIV virions released from VLP-DCs increased. Both the increase in A3G/3F expression and the inhibition of HIV-1 replication were reversed by anti-IFN-α or anti-IFNAR antibodies. Our findings in this study provide insight into the mechanism of Gag-VLP-induced inhibition of HIV-1 replication in DCs and T cells.

  15. APOBEC3G对HIV-1及其Vif缺失株的抑制作用%Restriction of HIV-1 and the Vif-deficiency strain by APOBEC3G

    Institute of Scientific and Technical Information of China (English)

    李岚; 曾毅

    2011-01-01

    Objective To study the restriction of HIV-1 and the Vif-deficient strain. Methods Viruses of HIV-1 wild type( BH10 WT) or the Vd-deficient strain( BH10 ΔVif) produced from transfected 293T cells were used to infect various cell lines, including MT4 and H9. The results were determined by reverse transcriptase ( RTase ) assay. Molecular-cloning technique was used to construct expression plasmid pEGFP-3G which express APOBEC3G with a C-terminal GFP tag. The virus strains of BH10 WT or BH10 ΔVif co-transfection with different dose of pEGFP-3G in 293T cells, and the expression of APOBEC3G-GFP was observed by live cell fluorescence microscopy. The infectivity of virus was determined by multinuclear activation of galactosidase indicator(MAGI) assay and RTase assay. Results BH10 WT replication in MT4 cells showed much faster replication kinetics than that in H9 cells, with peak RT values being observed as early as 4 days post-infection. RT activity of BH10 ΔVif in H9 cells was suppressed almost to the level of negative control and that in MT4 cells was observed on the 12th day. GFP-APOBEC3G and a GFP-only control localized to the cytoplasmic and cell-wide, respectively. The titer of BH10 ΔVif by MAGI assay is about 2.75 × 104 U/mL. The titer of viruses, produced in 293T cells by cotransfection with increasing amounts of APOBEC3G, was significantly reduced from 1.48 × 103 U/mL to 0.33 × 103 U/mL. The infectivity of BH10 ΔVif produced in the presence of 0.2 μg of co-transfected pEGFP-3G was twenty fold less infectious than BH10 ΔVif produced in the absence of APOBEC3G.Conclusion The anti-HIV activity of APOBEC3G was dose-dependent, and HIV-1 Vif has the essential role in the virus replication. Based on the results we would construct a new platform to accurately and promptly select efficacious drugs.%目的 研究细胞内在抗病毒因子APOBEC3G对HIV-1及其Vif缺失株的抑制作用.方法 HIV-1野生株病毒(BH10 WT)和Vif缺失株病毒(BH10

  16. HIV-1Vif与人APOBEC3G为靶点的抗HIV-1药物的研究方法%Research methods of antiHIV-1 inhibitors targeting at Vif-APOBEC3G axis

    Institute of Scientific and Technical Information of China (English)

    乔新华; 张文俊; 李泽琳; 曾毅

    2011-01-01

    The mammalian APOBEC3G protein( apolipoprotein B mRNA-editing enzyme catalytic polypeptide 3 protein G,APOBEC3G) is an important component of the cellular innate immune response to retroviral infection. APOBEC3G can extinguish HIV-1 ( human immunodeficiency virus type 1 ) infectivity by its incorporation into virus particles and subsequent cytosine deaminase activity to block replication of HIV-1. HIV-1 Vif ( viral infectivity factor) suppresses various APOBEC3 proteins through a common mechanism which induces the degradation of target proteins. Therefore, the interrelation of Vif-APOBEC3G has been extensively studied, which represents attractive targets for the development of novel inhibitors. We summarize the papers in which the detection technique and methords have been developed to assay the anti-HIV activity and its mechanism, such as western-blotting, co-immunoprecipitation,pulse-chase experiments,bioluminescence resonance energy transfer, biomolecular interaction analysis. This review is towards developing therapeutics aimed at the Vif -APOBEC3G axis.%人载脂蛋白B mRNA编辑酶催化多肽样蛋白3G(apolipoprotein B mRNA-editing enzyme catalytic polypeptide 3 protein G,APOBEC3G)是宿主的抗HIV-1(human immunodeficiency virus type Ⅰ)因子,而HIV-1辅助蛋白--病毒感染因子Vif(viral infectivity factor)可通过介导蛋白酶体途径降解APOBEC3G,因此针对APOBEC3G及HIV-1Vif进行抑制剂设计已经成为抗HIV-1药物研究新的方向之一,相应用于研究Vif-APOBEC3G相互作用的方法也越来越多,如免疫印迹、免疫杂交、脉冲追踪试验、生物发光共振能量转移检测、BIAcore检测等.作者将目前用于以Vif-APOBEC3G为靶点的药物的筛选及作用机制的研究方法进行了综述,为基于此的研究提供了策略.

  17. APOBEC3G与Vif在HIV-1感染中的作用%The Roles of APOBEC3G and Vif in HIV-1 Infections

    Institute of Scientific and Technical Information of China (English)

    马寅佳; 杨怡姝; 曾毅

    2012-01-01

    Apolipoprotein B mRNA-editing catalytic polypeptide-like (APOBEC) proteins are cytidine deaminases that exert antiviral activity to inhibit the infection of many viruses, especially retrovintses. The antiviral activity of AP0BEC-3G( A3G) and APOBEC-3F are stronger than other family members. A3G inhibits human immunodeficiency virus (HIV) infection through cytidine deamination and non-cytidine deamination. However, the degradation of A3G by the ubiquitin- proteasome system can be antagonized by HIV-1 viral infectivity factor (Vif). The study of the interaction of A3G and Vif will be informative for its connection with HIV-1 treatments.%载脂蛋白B mRNA编辑催化多肽样(apolipoprotein B mRNA-editing catalytic polypeptide-like,APOBEC)蛋白是一组胞嘧啶脱氨基酶,具有天然的抗病毒活性,对多种病毒具有抑制作用,特别是逆转录病毒.APOBEC3蛋白能够抑制人类免疫缺陷病毒(HIV-1)的感染,其中APOBEC3G和APOBEC3F的作用最强.APOBEC3G能够通过胞嘧啶脱氨基作用和非胞嘧啶脱氨基作用抑制病毒感染.HIV-1病毒感染因子(Vif)蛋白主要经泛素-蛋白酶体途径介导APOBEC3G降解,从而拮抗其抗病毒作用.APOBEC3G和Vif之间相互作用的研究对于寻求新的抗HIV治疗靶点具有重要意义.

  18. DNA Mutagenic Activity and Capacity for HIV-1 Restriction of the Cytidine Deaminase APOBEC3G Depends on Whether DNA or RNA Binds to Tyrosine 315.

    Science.gov (United States)

    Polevoda, Bogdan; Joseph, Rebecca; Friedman, Alan E; Bennett, Ryan P; Greiner, Rebecca; De Zoysa, Thareendra; Stewart, Ryan A; Smith, Harold C

    2017-04-05

    APOBEC3G (A3G) belongs to the AID/APOBEC protein family of cytidine deaminases (CDA) that bind to nucleic acids. A3G mutates the HIV genome by deamination of dC to dU, leading to accumulation of virus-inactivating mutations. Binding to cellular RNAs inhibits A3G binding to substrate single-stranded (ss) DNA and CDA activity. RNA and ssDNA bind to the same three A3G tryptic peptides (amino acids 181-194, 314-320, and 345-374) that form parts of a continuously exposed protein surface extending from the catalytic domain in the C-terminus of A3G to its N-terminus. We show here that the A3G tyrosines 181 and 315 directly cross-link ssDNA. Binding experiments showed that a Y315A mutation alone significantly reduced A3G binding to both ssDNA and RNA, whereas Y181A and Y182A mutations only moderately affected A3G nucleic acid binding. Consistent with these findings, the Y315A mutant exhibited little to no deaminase activity in an E. coli DNA mutator reporter, while Y181A and Y182A mutants retained ~50% of wild-type A3G activity. The Y315A mutant also showed a markedly reduced ability to assemble into viral particles and had reduced antiviral activity. In uninfected cells, the impaired RNA-binding capacity of Y315A was evident by a shift of A3G from high-molecular-mass ribonucleoprotein complexes to low-molecular-mass complexes. We conclude that Y315 is essential for coordinating ssDNA interaction with or entry to the deaminase domain and hypothesize that RNA bound to Y315 may be sufficient to competitively inhibit ssDNA deaminase-dependent antiviral activity.

  19. APOBEC3G induces a hypermutation gradient: purifying selection at multiple steps during HIV-1 replication results in levels of G-to-A mutations that are high in DNA, intermediate in cellular viral RNA, and low in virion RNA

    Directory of Open Access Journals (Sweden)

    Pathak Vinay K

    2009-02-01

    Full Text Available Abstract Background Naturally occurring Vif variants that are unable to inhibit the host restriction factor APOBEC3G (A3G have been isolated from infected individuals. A3G can potentially induce G-to-A hypermutation in these viruses, and hypermutation could contribute to genetic variation in HIV-1 populations through recombination between hypermutant and wild-type genomes. Thus, hypermutation could contribute to the generation of immune escape and drug resistant variants, but the genetic contribution of hypermutation to the viral evolutionary potential is poorly understood. In addition, the mechanisms by which these viruses persist in the host despite the presence of A3G remain unknown. Results To address these questions, we generated a replication-competent HIV-1 Vif mutant in which the A3G-binding residues of Vif, Y40RHHY44, were substituted with five alanines. As expected, the mutant was severely defective in an A3G-expressing T cell line and exhibited a significant delay in replication kinetics. Analysis of viral DNA showed the expected high level of G-to-A hypermutation; however, we found substantially reduced levels of G-to-A hypermutation in intracellular viral RNA (cRNA, and the levels of G-to-A mutations in virion RNA (vRNA were even further reduced. The frequencies of hypermutation in DNA, cRNA, and vRNA were 0.73%, 0.12%, and 0.05% of the nucleotides sequenced, indicating a gradient of hypermutation. Additionally, genomes containing start codon mutations and early termination codons within gag were isolated from the vRNA. Conclusion These results suggest that sublethal levels of hypermutation coupled with purifying selection at multiple steps during the early phase of viral replication lead to the packaging of largely unmutated genomes, providing a mechanism by which mutant Vif variants can persist in infected individuals. The persistence of genomes containing mutated gag genes despite this selection pressure indicates that dual

  20. 基于Vif-APOBEC3G相互作用的抗HIV-1药物研究%Anti-HIV-1 agents based on Vif-APOBEC3G interaction: research advances

    Institute of Scientific and Technical Information of China (English)

    张兴杰; 王睿睿; 郑永唐

    2010-01-01

    载脂蛋白B mRNA编辑酶催化多肽样蛋白3G(apolipoprotein B mRNA-editing enzyme catalyticpolypeptidelike 3G,APOBEC3G或A3G)是人体天然抗病毒分子,可以使病毒逆转录形成的cDNA的胞嘧啶(C)脱氨为尿嘧啶(U),产生鸟嘌呤(G)→腺嘌呤(A)超突变,导致病毒转录产物突变,从而达到抑制病毒复制的作用.HIV-1的辅助蛋白Vif,可与APOBEC3G相互作用并导致其被降解,使得这一天然抗病毒机制失效,进而增强了HIV的感染力.Vif与APOBEC3G这种相互作用为抗HIV药物提供了新靶点.针对Vif-APOBEC3G相互作用的抗HIV抑制剂已经成为研究热点.本文综述了Vif和APOBEC3G的结构、二者的相互作用,以及基于这一相互作用的抗HIV-1抑制剂研究进展.

  1. Random mutagenesis MAPPIT analysis identifies binding sites for Vif and Gag in both cytidine deaminase domains of Apobec3G.

    Directory of Open Access Journals (Sweden)

    Isabel Uyttendaele

    Full Text Available The mammalian two-hybrid system MAPPIT allows the detection of protein-protein interactions in intact human cells. We developed a random mutagenesis screening strategy based on MAPPIT to detect mutations that disrupt the interaction of one protein with multiple protein interactors simultaneously. The strategy was used to detect residues of the human cytidine deaminase Apobec3G that are important for its homodimerization and its interaction with the HIV-1 Gag and Vif proteins. The strategy is able to identify the previously described head-to-head homodimerization interface in the N-terminal domain of Apobec3G. Our analysis further detects two new potential interaction surfaces in the N-and C-terminal domain of Apobec3G for interaction with Vif and Gag or for Apobec3G dimerization.

  2. APOBEC3G抗HIV-1的分子机制及Vif基因对其拮抗作用研究进展%Research and Development of Molecular Mechanism of APOBEC3G's Anti HIV-1 Effects and Vif's Antagonism to Them

    Institute of Scientific and Technical Information of China (English)

    屠燕捷

    2012-01-01

    The high pathogenic rate and high mortality rates of AIDS have caught more attention for recent three decades. The expectation is focused on HIV/AIDS prevention and great breakthrough in Traditional Chinese Medicine (TCM) research. This article introduced research and development of molecular mechanism of APOBEC3G's anti HIV-1 effects and the gene vif's antagonism to them. The goal is to discuss the significance of HIV gene therapy and the potential research direction of TCM for HIV treatment.%近30年,艾滋病的高致病率和高死亡率一直被医学界高度关注,期望通过中医药研究在艾滋病防治上寻求突破,从而引发了中医药研究与分子生物学研究交叉与结合.由于近10年HIV的分子生物学研究文献,发现HIV的辅助蛋白vif和APOBEC3G为当前艾滋病致病机制研究的热点.本文对HIV的辅助蛋白vif的生物学特性、APOBEC3G抗HIV-1的分子机制及vif与APOBEC3G相互作用的新近研究成果进行整理分析,探讨基于此进行HIV基因治疗的意义以及中医药治疗HIV可能的研究方向.

  3. First-In-Class Small Molecule Inhibitors of the Single-Strand DNA Cytosine Deaminase APOBEC3G

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ming; Shandilya, Shivender M.D.; Carpenter, Michael A.; Rathore, Anurag; Brown, William L.; Perkins, Angela L.; Harki, Daniel A.; Solberg, Jonathan; Hook, Derek J.; Pandey, Krishan K.; Parniak, Michael A.; Johnson, Jeffrey R.; Krogan, Nevan J.; Somasundaran, Mohan; Ali, Akbar; Schiffer, Celia A.; Harris, Reuben S. (Pitt); (UMASS, MED); (SLUHSC); (UCSF); (UMM)

    2012-04-04

    APOBEC3G is a single-stranded DNA cytosine deaminase that comprises part of the innate immune response to viruses and transposons. Although APOBEC3G is the prototype for understanding the larger mammalian polynucleotide deaminase family, no specific chemical inhibitors exist to modulate its activity. High-throughput screening identified 34 compounds that inhibit APOBEC3G catalytic activity. Twenty of 34 small molecules contained catechol moieties, which are known to be sulfhydryl reactive following oxidation to the orthoquinone. Located proximal to the active site, C321 was identified as the binding site for the inhibitors by a combination of mutational screening, structural analysis, and mass spectrometry. Bulkier substitutions C321-to-L, F, Y, or W mimicked chemical inhibition. A strong specificity for APOBEC3G was evident, as most compounds failed to inhibit the related APOBEC3A enzyme or the unrelated enzymes E. coli uracil DNA glycosylase, HIV-1 RNase H, or HIV-1 integrase. Partial, but not complete, sensitivity could be conferred to APOBEC3A by introducing the entire C321 loop from APOBEC3G. Thus, a structural model is presented in which the mechanism of inhibition is both specific and competitive, by binding a pocket adjacent to the APOBEC3G active site, reacting with C321, and blocking access to substrate DNA cytosines.

  4. APOBEC3G expression is correlated with poor prognosis in colon carcinoma patients with hepatic metastasis.

    Science.gov (United States)

    Lan, Huanrong; Jin, Ketao; Gan, Meifu; Wen, Shouxiang; Bi, Tienan; Zhou, Shenkang; Zhu, Naibiao; Teng, Lisong; Yu, Wenjie

    2014-01-01

    Increased expression of apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G) in human primary colorectal tumors and hepatic metastasis has been detected. However, the clinical relevance of APOBEC3G in colon carcinoma hepatic metastasis remains uncertain. The aim of this study was to assess the prognostic value of APOBEC3G in colon carcinoma patients with hepatic metastasis after hepatic resection. APOBEC3G expression was evaluated by immunohistochemistry in paraffin-embedded primary colon carcinoma and paired hepatic metastasis tissues from 136 patients with liver metastasis from colon carcinoma that underwent hepatic resection. The relation between APOBEC3G expression and clinicopathologic factors and long-term prognosis in these 136 patients was retrospectively examined. The prognostic significance of negative or positive APOBEC3G expression in colon carcinoma hepatic metastasis was assessed using Kaplan-Meier survival analysis and log-rank tests. Positive expression of APOBEC3G was correlated with liver metastasis of colon cancer. Univariate analysis indicated significantly worse overall survival (OS) for patients with a positive APOBEC3G expression in colon carcinoma hepatic metastasis than for patients with a negative APOBEC3G expression. Multivariate analysis showed positive-APOBEC3G in colon carcinoma hepatic metastasis to be an independent prognostic factor for OS after hepatic resection (P = 0.000). Positive expression of APOBEC3G was statistically significantly associated with poor prognosis of colon carcinoma patients with hepatic metastasis. APOBEC3G could be a novel predictor for poor prognosis of colon carcinoma patients with hepatic metastasis after hepatic resection.

  5. APOBEC3G-Augmented Stem Cell Therapy to Modulate HIV Replication: A Computational Study.

    Directory of Open Access Journals (Sweden)

    Iraj Hosseini

    Full Text Available The interplay between the innate immune system restriction factor APOBEC3G and the HIV protein Vif is a key host-retrovirus interaction. APOBEC3G can counteract HIV infection in at least two ways: by inducing lethal mutations on the viral cDNA; and by blocking steps in reverse transcription and viral integration into the host genome. HIV-Vif blocks these antiviral functions of APOBEC3G by impeding its encapsulation. Nonetheless, it has been shown that overexpression of APOBEC3G, or interfering with APOBEC3G-Vif binding, can efficiently block in vitro HIV replication. Some clinical studies have also suggested that high levels of APOBEC3G expression in HIV patients are correlated with increased CD4+ T cell count and low levels of viral load; however, other studies have reported contradictory results and challenged this observation. Stem cell therapy to replace a patient's immune cells with cells that are more HIV-resistant is a promising approach. Pre-implantation gene transfection of these stem cells can augment the HIV-resistance of progeny CD4+ T cells. As a protein, APOBEC3G has the advantage that it can be genetically encoded, while small molecules cannot. We have developed a mathematical model to quantitatively study the effects on in vivo HIV replication of therapeutic delivery of CD34+ stem cells transfected to overexpress APOBEC3G. Our model suggests that stem cell therapy resulting in a high fraction of APOBEC3G-overexpressing CD4+ T cells can effectively inhibit in vivo HIV replication. We extended our model to simulate the combination of APOBEC3G therapy with other biological activities, to estimate the likelihood of improved outcomes.

  6. Vif proteins from diverse primate lentiviral lineages use the same binding site in APOBEC3G.

    Science.gov (United States)

    Letko, Michael; Silvestri, Guido; Hahn, Beatrice H; Bibollet-Ruche, Frederick; Gokcumen, Omer; Simon, Viviana; Ooms, Marcel

    2013-11-01

    APOBEC3G (A3G) is a cytidine deaminase that restricts human immunodeficiency virus type 1 (HIV-1) and other lentiviruses. Most of these viruses encode a Vif protein that directly binds A3G and leads to its proteasomal degradation. Both Vif proteins of HIV-1 and African green monkey simian immunodeficiency virus (SIVagm) bind residue 128 of A3G. However, this position does not control the A3G degradation by Vif variants derived from HIV-2 and SIVmac, which both originated from SIV of sooty mangabey monkeys (SIVsmm), suggesting that the A3G binding site for Vif proteins of the SIVsmm/HIV-2 lineage differs from that of HIV-1. To map the SIVsmm Vif binding site of A3G, we performed immunoprecipitations of individual A3G domains, Vif/A3G degradation assays and a detailed mutational analysis of human A3G. We show that A3G residue 129, but not the adjacent position 128, confers susceptibility to degradation by SIVsmm Vif. An artificial A3G mutant, the P129D mutant, was resistant to degradation by diverse Vifs from HIV-1, HIV-2, SIVagm, and chimpanzee SIV (SIVcpz), suggesting a conserved lentiviral Vif binding site. Gorilla A3G naturally contains a glutamine (Q) at position 129, which makes its A3G resistant to Vifs from diverse lineages. We speculate that gorilla A3G serves as a barrier against SIVcpz strains. In summary, we show that Vif proteins from distinct lineages bind to the same A3G loop, which includes positions 128 and 129. The multiple adaptations within this loop among diverse primates underscore the importance of counteracting A3G in lentiviral evolution.

  7. Structure of the Vif-binding domain of the antiviral enzyme APOBEC3G.

    Science.gov (United States)

    Kouno, Takahide; Luengas, Elizabeth M; Shigematsu, Megumi; Shandilya, Shivender M D; Zhang, JingYing; Chen, Luan; Hara, Mayuko; Schiffer, Celia A; Harris, Reuben S; Matsuo, Hiroshi

    2015-06-01

    The human APOBEC3G (A3G) DNA cytosine deaminase restricts and hypermutates DNA-based parasites including HIV-1. The viral infectivity factor (Vif) prevents restriction by triggering A3G degradation. Although the structure of the A3G catalytic domain is known, the structure of the N-terminal Vif-binding domain has proven more elusive. Here, we used evolution- and structure-guided mutagenesis to solubilize the Vif-binding domain of A3G, thus permitting structural determination by NMR spectroscopy. A smaller zinc-coordinating pocket and altered helical packing distinguish the structure from previous catalytic-domain structures and help to explain the reported inactivity of this domain. This soluble A3G N-terminal domain is bound by Vif; this enabled mutagenesis and biochemical experiments, which identified a unique Vif-interacting surface formed by the α1-β1, β2-α2 and β4-α4 loops. This structure sheds new light on the Vif-A3G interaction and provides critical information for future drug development.

  8. Crystal structure of the anti-viral APOBEC3G catalytic domain and functional implications

    Energy Technology Data Exchange (ETDEWEB)

    Holden, Lauren G.; Prochnow, Courtney; Chang, Y. Paul; Bransteitter, Ronda; Chelico, Linda; Sen, Udayaditya; Stevens, Raymond C.; Goodman, Myron F.; Chen, Xiaojiang S. (USC); (Scripps)

    2009-04-07

    The APOBEC family members are involved in diverse biological functions. APOBEC3G restricts the replication of human immunodeficiency virus (HIV), hepatitis B virus and retroelements by cytidine deamination on single-stranded DNA or by RNA binding. Here we report the high-resolution crystal structure of the carboxy-terminal deaminase domain of APOBEC3G (APOBEC3G-CD2) purified from Escherichia coli. The APOBEC3G-CD2 structure has a five-stranded {beta}-sheet core that is common to all known deaminase structures and closely resembles the structure of another APOBEC protein, APOBEC2. A comparison of APOBEC3G-CD2 with other deaminase structures shows a structural conservation of the active-site loops that are directly involved in substrate binding. In the X-ray structure, these APOBEC3G active-site loops form a continuous 'substrate groove' around the active centre. The orientation of this putative substrate groove differs markedly (by 90 degrees) from the groove predicted by the NMR structure. We have introduced mutations around the groove, and have identified residues involved in substrate specificity, single-stranded DNA binding and deaminase activity. These results provide a basis for understanding the underlying mechanisms of substrate specificity for the APOBEC family.

  9. Inhibition of hepatitis B virus replication by APOBEC3G in vitro and in vivo

    Institute of Scientific and Technical Information of China (English)

    Yan-Chang Lei; Dong-Liang Yang; You-Hua Hao; Zheng-Mao Zhang; Yong-Jun Tian; Bao-Ju Wang; Yan Yang; Xi-Ping Zhao; Meng-Ji Lu; Fei-Li Gong

    2006-01-01

    AIM: To investigate the effect of APOBEC3G mediated antiviral activity against hepatitis B virus (HBV) in cell cultures and replication competent HBV vector-based mouse model.METHODS: The mammalian hepatoma cells Huh7 and HepG2 were cotransfected with various amounts of CMV-driven expression vector encoding APOBEC3G and replication competent 1.3 fold over-length HBV. Levels of HBsAg and HBeAg in the media of the transfected cells were determined by ELISA. The expression of HBcAg in transfected cells was detected by western blot. HBV DNA and RNA from intracellular core particles were examined by Northern and Southern blot analyses. To assess activity of the APOBEC3G in vivo, an HBV vector-based model was used in which APOBEC3G and the HBV vector were co-delivered via high-volume tail vein injection.Levels of HBsAg and HBV DNA in the sera of mice as well as HBV core-associated RNA in the liver of mice were determined by ELISA and quantitative PCR analysis respectively.RESULTS: There was a dose dependent decrease in the levels of intracellular core-associated HBV DNA and extracellular production of HBsAg and HBeAg. The levels of intracellular core-associated viral RNA also decreased,but the expression of HBcAg in transfected cells showed almost no change. Consistent with in vitro results,levels of HBsAg in the sera of mice were dramatically decreased. More than 1.5 log10 decrease in levels of serum HBV DNA and liver HBV RNA were observed in the APOBEC3G-treated groups compared with the control groups.CONCLUSION: These findings indicate that APOBEC3G could suppress HBV replication and antigen expression both in vivo and in vitro, promising an advance in treatment of HBV infection.

  10. APOBEC3G is a single-stranded DNA cytidine deaminase and functions independently of HIV reverse transcriptase

    Science.gov (United States)

    Suspène, Rodolphe; Sommer, Peter; Henry, Michel; Ferris, Stéphane; Guétard, Denise; Pochet, Sylvie; Chester, Ann; Navaratnam, Naveenan; Wain-Hobson, Simon; Vartanian, Jean-Pierre

    2004-01-01

    In the absence of the viral vif gene, human immunodeficiency virus (HIV) may be restricted by the APOBEC3G gene on chromosome 22. The role of the HIV Vif protein is to exclude host cell APOBEC3G from the budding virion. As APOBEC3G shows sequence homology to cytidine deaminases, it is presumed that in the absence of Vif, cytidine residues in the cDNA are deaminated yielding uracil. It is not known if additional proteins mediate APOBEC3G function or if deamination occurs in concert with reverse transcription. This report describes an in vitro assay showing that Baculovirus derived APOBEC3G alone extensively deaminates cDNA independently of reverse transcriptase. It reproduces the dinucleotide context typical of G → A hypermutants derived from a Δvif virus. By using an RNaseH– form of reverse transcriptase, it was shown that the cDNA has to be free of its RNA template to allow deamination. APOBEC3G deamination of dC or dCTP was not detected. In short, APOBEC3G is a single-stranded DNA cytidine deaminase capable of restricting retroviral replication. PMID:15121899

  11. Insights into the dual activity of SIVmac239 Vif against human and African green monkey APOBEC3G.

    Directory of Open Access Journals (Sweden)

    Ritu Gaur

    Full Text Available Human immunodeficiency virus type 1 (HIV-1 Vif is essential for viral evasion of the host antiviral protein APOBEC3G (APO3G. The Vif protein from a distantly related African green monkey (Agm simian immunodeficiency virus (SIVagm is unable to suppress the antiviral activity of human APO3G but is active against Agm APO3G. SIVmac Vif on the other hand, possesses antiviral activity against both human and Agm APO3G. In this study, we were interested in mapping domains in SIVmac Vif that are responsible for its dual activity against human and Agm APO3G. We constructed a series of Vif chimeras by swapping domains in SIVmac Vif with equivalent regions from SIVagm Vif and determined their activity against human and Agm APO3G. We found that replacing any region in SIVmac Vif by corresponding fragments from SIVagm Vif only moderately reduced the activity of the chimeras against Agm APO3G but in all cases resulted in a severe loss of activity against human APO3G. These results suggest that the domains in SIVmac Vif required for targeting human and Agm APO3G are distinct and cannot be defined as linear amino acid motifs but rather appear to depend on the overall structure of full-length SIVmac Vif.

  12. A hydrodynamic analysis of APOBEC3G reveals a monomer-dimer-tetramer self-association that has implications for anti-HIV function.

    Science.gov (United States)

    Salter, Jason D; Krucinska, Jolanta; Raina, Jay; Smith, Harold C; Wedekind, Joseph E

    2009-11-17

    The innate antiviral factor APOBEC3G (A3G) possesses RNA binding activity and deaminates HIV-1 DNA. High-molecular mass forms of A3G can be isolated from a variety of cell types but exhibit limited deaminase activity relative to low-molecular mass species prepared under RNA-depleted conditions. To investigate the fundamental oligomeric state and shape of A3G, we conducted sedimentation velocity analyses of the pure enzyme under RNA-deficient conditions. The results reveal a predominant dimer in equilibrium with minor monomeric and tetrameric species. Hydrodynamic modeling of the dimer supports an extended cylindrical shape that assembles into an elongated tetramer. Overall, the results provide physical restraints for the A3G quaternary structure that have implications for modulating antiviral function.

  13. Multi-scale modeling of HIV infection in vitro and APOBEC3G-based anti-retroviral therapy.

    Directory of Open Access Journals (Sweden)

    Iraj Hosseini

    2012-02-01

    Full Text Available The human APOBEC3G is an innate restriction factor that, in the absence of Vif, restricts HIV-1 replication by inducing excessive deamination of cytidine residues in nascent reverse transcripts and inhibiting reverse transcription and integration. To shed light on impact of A3G-Vif interactions on HIV replication, we developed a multi-scale computational system consisting of intracellular (single-cell, cellular and extracellular (multicellular events by using ordinary differential equations. The single-cell model describes molecular-level events within individual cells (such as production and degradation of host and viral proteins, and assembly and release of new virions, whereas the multicellular model describes the viral dynamics and multiple cycles of infection within a population of cells. We estimated the model parameters either directly from previously published experimental data or by running simulations to find the optimum values. We validated our integrated model by reproducing the results of in vitro T cell culture experiments. Crucially, both downstream effects of A3G (hypermutation and reduction of viral burst size were necessary to replicate the experimental results in silico. We also used the model to study anti-HIV capability of several possible therapeutic strategies including: an antibody to Vif; upregulation of A3G; and mutated forms of A3G. According to our simulations, A3G with a mutated Vif binding site is predicted to be significantly more effective than other molecules at the same dose. Ultimately, we performed sensitivity analysis to identify important model parameters. The results showed that the timing of particle formation and virus release had the highest impacts on HIV replication. The model also predicted that the degradation of A3G by Vif is not a crucial step in HIV pathogenesis.

  14. Production of infectious human immunodeficiency virus type 1 does not require depletion of APOBEC3G from virus-producing cells

    Directory of Open Access Journals (Sweden)

    Goila-Gaur Ritu

    2004-09-01

    Full Text Available Abstract Background The human immunodeficiency virus Vif protein overcomes the inhibitory activity of the APOBEC3G cytidine deaminase by prohibiting its packaging into virions. Inhibition of APOBEC3G encapsidation is paralleled by a reduction of its intracellular level presumably caused by the Vif-induced proteasome-dependent degradation of APOBEC3G. Results In this report we employed confocal microscopy to study the effects of Vif on the expression of APOBEC3G on a single cell level. HeLa cells dually transfected with Vif and APOBEC3G expression vectors revealed efficient co-expression of the two proteins. Under optimal staining conditions approximately 80% of the transfected cells scored double-positive for Vif and APOBEC3G. However, the proportion of double-positive cells observed in identical cultures varied dependent on the fixation protocol and on the choice of antibodies used ranging from as low as 40% to as high as 80% of transfected cells. Importantly, single-positive cells expressing either Vif or APOBEC3G were observed both with wild type Vif and a biologically inactive Vif variant. Thus, the lack of APOBEC3G in some Vif-expressing cells cannot be attributed to Vif-induced degradation of APOBEC3G. These findings are consistent with our results from immunoblot analyses that revealed only moderate effects of Vif on the APOBEC3G steady state levels. Of note, viruses produced under such conditions were fully infectious demonstrating that the Vif protein used in our analyses was both functional and expressed at saturating levels. Conclusions Our results suggest that Vif and APOBEC3G can be efficiently co-expressed. Thus, depletion of APOBEC3G from Vif expressing cells as suggested previously is not a universal property of Vif and thus is not imperative for the production of infectious virions.

  15. Inhibition of a NEDD8 Cascade Restores Restriction of HIV by APOBEC3G.

    Directory of Open Access Journals (Sweden)

    David J Stanley

    2012-12-01

    Full Text Available Cellular restriction factors help to defend humans against human immunodeficiency virus (HIV. HIV accessory proteins hijack at least three different Cullin-RING ubiquitin ligases, which must be activated by the small ubiquitin-like protein NEDD8, in order to counteract host cellular restriction factors. We found that conjugation of NEDD8 to Cullin-5 by the NEDD8-conjugating enzyme UBE2F is required for HIV Vif-mediated degradation of the host restriction factor APOBEC3G (A3G. Pharmacological inhibition of the NEDD8 E1 by MLN4924 or knockdown of either UBE2F or its RING-protein binding partner RBX2 bypasses the effect of Vif, restoring the restriction of HIV by A3G. NMR mapping and mutational analyses define specificity determinants of the UBE2F NEDD8 cascade. These studies demonstrate that disrupting host NEDD8 cascades presents a novel antiretroviral therapeutic approach enhancing the ability of the immune system to combat HIV.

  16. Catalytic analysis of APOBEC3G involving real-time NMR spectroscopy reveals nucleic acid determinants for deamination.

    Directory of Open Access Journals (Sweden)

    Keisuke Kamba

    Full Text Available APOBEC3G (A3G is a single-stranded DNA-specific cytidine deaminase that preferentially converts cytidine to uridine at the third position of triplet cytosine (CCC hotspots. A3G restricts the infectivity of viruses, such as HIV-1, by targeting CCC hotspots scattered through minus DNA strands, reverse-transcribed from genomic RNA. Previously, we developed a real-time NMR method and elucidated the origin of the 3'→5' polarity of deamination of DNA by the C-terminal domain of A3G (CD2, which is a phenomenon by which a hotspot located closer to the 5'-end is deaminated more effectively than one less close to the 5'-end, through quantitative analysis involving nonspecific binding to and sliding along DNA. In the present study we applied the real-time NMR method to analyze the catalytic activity of CD2 toward DNA oligonucleotides containing a nucleotide analog at a single or multiple positions. Analyses revealed the importance of the sugar and base moieties throughout the consecutive 5 nucleotides, the CCC hotspot being positioned at the center. It was also shown that the sugar or base moieties of the nucleotides outside this 5 nucleotide recognition sequence are also relevant as to CD2's activity. Analyses involving DNA oligonucleotides having two CCC hotspots linked by a long sequence of either deoxyribonucleotides, ribonucleotides or abasic deoxyribonucleotides suggested that the phosphate backbone is required for CD2 to slide along the DNA strand and to exert the 3'→5' polarity. Examination of the effects of different salt concentrations on the 3'→5' polarity indicated that the higher the salt concentration, the less prominent the 3'→5' polarity. This is most likely the result of alleviation of sliding due to a decrease in the affinity of CD2 with the phosphate backbone at high salt concentrations. We also investigated the reactivity of substrates containing 5-methylcytidine (5mC or 5-hydroxymethylcytidine, and found that A3G exhibited low

  17. Hydrodynamic and Functional Analysis of HIV-1 Vif Oligomerization

    OpenAIRE

    Stephen M Techtmann; Ghirlando, Rodolfo; Kao, Sandra; Strebel, Klaus; Maynard, Ernest L.

    2012-01-01

    HIV-1 Vif is an accessory protein that induces the proteasomal degradation of the host restriction factor, apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G). The N-terminal half of Vif binds to APOBEC3G and the C-terminal half binds to subunits of a cullin-5-based ubiquitin ligase. This Vif-directed ubiquitin ligase induces the degradation of APOBEC3G (a cytidine deaminase), and thereby protects the viral genome from mutation. A conserved PPLP motif near the C term...

  18. APOBEC3G oligomerization is associated with the inhibition of both Alu and LINE-1 retrotransposition.

    Directory of Open Access Journals (Sweden)

    Takayoshi Koyama

    Full Text Available Alu and LINE-1 (L1, which constitute ~11% and ~17% of the human genome, respectively, are transposable non-LTR retroelements. They transpose not only in germ cells but also in somatic cells, occasionally causing cancer. We have previously demonstrated that antiretroviral restriction factors, human APOBEC3 (hA3 proteins (A-H, differentially inhibit L1 retrotransposition. In this present study, we found that hA3 members also restrict Alu retrotransposition at differential levels that correlate with those observed previously for L1 inhibition. Through deletion analyses based on the best-characterized hA3 member human APOBEC3G (hA3G, its N-terminal 30 amino acids were required for its inhibitory activity against Alu retrotransposition. The inhibitory effect of hA3G on Alu retrotransposition was associated with its oligomerization that was affected by the deletion of its N-terminal 30 amino acids. Through structural modeling, the amino acids 24 to 28 of hA3G were predicted to be located at the interface of the dimer. The mutation of these residues resulted in abrogated hA3G oligomerization, and consistently abolished the inhibitory activity of hA3G against Alu retrotransposition. Importantly, the anti-L1 activity of hA3G was also associated with hA3G oligomerization. These results suggest that the inhibitory activities of hA3G against Alu and L1 retrotransposition might involve a common mechanism.

  19. Molecular modeling of human APOBEC3G to predict the binding modes of the inhibitor compounds IMB26 and IMB35

    Directory of Open Access Journals (Sweden)

    Zhixin Zhang

    2013-07-01

    Full Text Available APOBEC3G(A3G is a host cytidine deaminase that incorporates into HIV-1 virions and efficiently inhibits viral replication. The virally encoded protein Vif binds to A3G and induces its degradation, thereby counteracting the antiviral activity of A3G. Vif-mediated A3G degradation clearly represents a potential target for anti-HIV drug development. Currently, there is an urgent need for understanding the three dimensional structure of full-length A3G. In this work, we use a homology modeling approach to propose a structure for A3G based on the crystal structure of APOBEC2 (APO2 and the catalytic domain structure of A3G. Two compounds, IMB26 and IMB35, which have been shown to bind to A3G and block degradation by Vif, were docked into the A3G model and the binding modes were generated for further analysis. The results may be used to design or optimize molecules targeting Vif–A3G interaction, and lead to the development of novel anti-HIV drugs.

  20. Association of APOBEC3G genotypes and CD4 decline in Thai and Cambodian HIV-infected children with moderate immune deficiency

    Directory of Open Access Journals (Sweden)

    Bunupuradah Torsak

    2012-11-01

    Full Text Available Abstract Introduction Human APOBEC3G is a host defense factor that potently inhibits HIV replication. We hypothesize that HIV-infected children with a genetic variant of APOBEC3G will have a more rapid disease progression. Methods Antiretroviral therapy (ART-naïve children, aged 1–12 years old with CD4 15-24% and without severe HIV-related symptoms were enrolled. The children had CD4% and absolute CD4 counts every 12 weeks and HIV-RNA every 24 weeks until 144 weeks. ART was started when CD4% declined to APOBEC3G genetic variants were performed by PCR-based restriction fragment length polymorphism techniques from peripheral blood mononuclear cells. Random-effect linear regression analysis was performed to correlate APOBEC3G genotypes and disease progression. Results 147 children, 35% male, with a median (IQR age of 6.5 (4.3-8.8 years were enrolled. CDC N:A:B were 1:63:36%. Median baseline values were 20% for CD4% 605 cells/mm3 for CD4 count and 4.7 log10copies/mL for HIV-RNA. The frequencies of APOBEC3G genotypes AA (186H/H, AG (186H/R, GG (186R/R were 86%, 12%, and 2% respectively. The APOBEC3G genotype GG was associated with a significant decline in CD4% -5.1% (−8.9 to −1.2%, p3, pAPOBEC3G genotypes with HIV-RNA changes overtime (p=0.16 or progression to CDC B and C (p=0.49 were observed. Conclusions APOBEC3G genotype GG was significantly associated with a more rapid decline in CD4. APOBEC3G’s antiviral effects on HIV disease progression in children should be further explored.

  1. 固有免疫的新成员——APOBEC3G

    Institute of Scientific and Technical Information of China (English)

    吴小霞; 马义才

    2005-01-01

    最近,对Vif的研究揭示了固有免疫的新成员——APOBEC3G,它是胞苷脱氨酶,致死性突变反转录病毒和反转录元件。APOBEC3G属于APOBEC家族,以DNA编辑的方式抑制反转录病毒复制,如HIV-1。APOBEC3G是广谱的抗病毒蛋白,对HBV也有强烈的抑制作用,但是作用机制有所不同。

  2. Newly synthesized APOBEC3G is incorporated into HIV virions, inhibited by HIV RNA, and subsequently activated by RNase H.

    Directory of Open Access Journals (Sweden)

    Vanessa B Soros

    2007-02-01

    Full Text Available APOBEC3G (A3G is a potent antiretroviral deoxycytidine deaminase that, when incorporated into HIV virions, hypermutates nascent viral DNA formed during reverse transcription. HIV Vif counters the effect of A3G by depleting intracellular stores of the enzyme, thereby blocking its virion incorporation. Through pulse-chase analyses, we demonstrate that virion A3G is mainly recruited from the cellular pool of newly synthesized enzyme compared to older "mature" A3G already residing in high-molecular-mass RNA-protein complexes. Virion-incorporated A3G forms a large complex with viral genomic RNA that is clearly distinct from cellular HMM A3G complexes, as revealed by both gel filtration and biochemical fractionation. Unexpectedly, the enzymatic activity of virion-incorporated A3G is lost upon its stable association with HIV RNA. The activity of the latent A3G enzyme is ultimately restored during reverse transcription by the action of HIV RNase H. Degradation of the viral genomic RNA by RNase H not only generates the minus-strand DNA substrate targeted by A3G for hypermutation but also removes the inhibitory RNA bound to A3G, thereby enabling its function as a deoxycytidine deaminase. These findings highlight an unexpected interplay between host and virus where initiation of antiviral enzymatic activity is dependent on the action of an essential viral enzyme.

  3. Inhibition of LINE-1 and Alu retrotransposition by exosomes encapsidating APOBEC3G and APOBEC3F.

    Science.gov (United States)

    Khatua, Atanu K; Taylor, Harry E; Hildreth, James E K; Popik, Waldemar

    2010-04-25

    Human cytidine deaminases, including APOBEC3G (A3G) and A3F, are part of a cellular defense system against retroviruses and retroelements including non-LTR retrotransposons LINE-1 (L1) and Alu. Expression of cellular A3 proteins is sufficient for inhibition of L1 and Alu retrotransposition, but the effect of A3 proteins transferred in exosomes on retroelement mobilization is unknown. Here, we demonstrate for the first time that exosomes secreted by CD4(+)H9 T cells and mature monocyte-derived dendritic cells encapsidate A3G and A3F and inhibit L1 and Alu retrotransposition. A3G is the major contributor to the inhibitory activity of exosomes, however, the contribution of A3F in H9 exosomes cannot be excluded. Additionally, we show that exosomes encapsidate mRNAs coding for A3 proteins. A3G mRNA, and less so A3F, was enriched in exosomes secreted by H9 cells. Exosomal A3G mRNA was functional in vitro. Whether exosomes inhibit retrotransposons in vivo requires further investigation.

  4. 病毒感染因子在APOBEC3G抗病毒中的拮抗作用%Antagonistic Effect of Virion Infectivity Factor and APOBEC3G in the Intrinsic Antiretroviral Defense

    Institute of Scientific and Technical Information of China (English)

    王运华; 张耀洲

    2008-01-01

    病毒感染因子(virion infectivity factor, Vif)是人免疫缺陷病毒(human im_mu_n_o_de_fi_cien_cy virus, HIV)的6个辅助蛋白之一, 是病毒进行有效复制所必需的.由于Vif功能的复杂性以及对相应复合物体系的不了解, 一直以来, 对Vif的研究进展缓慢.直到2002年发现载脂蛋白B mRNA编辑酶催化多肽样蛋白3G (apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G, APOBEC3G)是存在于细胞内的一种天然抗病毒因子后, Vif的功能才被逐步阐明.APOBEC3G主要通过嘧啶脱氨基活性使HIV-1的负链DNA在逆转录过程中发生致死性超突变, 从而起到抗病毒作用.HIV-1基因编码Vif来拮抗APOBEC3G, 二者在宿主细胞内达到动态平衡.Vif通过介导APOBEC3G降解、减少在胞内的表达、阻碍其向病毒粒子的包装以及促使其装配成无活性的高分子质量复合体等多种途径起到中和作用.对Vif/APOBEC3G相互作用及其调节机制的进一步研究, 将为新型抗HIV-1病毒药物的研制与开发提供理论依据.

  5. Hydrodynamic and functional analysis of HIV-1 Vif oligomerization.

    Science.gov (United States)

    Techtmann, Stephen M; Ghirlando, Rodolfo; Kao, Sandra; Strebel, Klaus; Maynard, Ernest L

    2012-03-13

    HIV-1 Vif is an accessory protein that induces the proteasomal degradation of the host restriction factor, apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G). The N-terminal half of Vif binds to APOBEC3G, and the C-terminal half binds to subunits of a cullin 5-based ubiquitin ligase. This Vif-directed ubiquitin ligase induces the degradation of APOBEC3G (a cytidine deaminase) and thereby protects the viral genome from mutation. A conserved PPLP motif near the C-terminus of Vif is essential for Vif function and is also involved in Vif oligomerization. However, the mechanism and functional significance of Vif oligomerization is unclear. We employed analytical ultracentrifugation to examine the oligomeric properties of Vif in solution. Contrary to previous reports, we find that Vif oligomerization does not require the conserved PPLP motif. Instead, our data suggest a more complex mechanism involving interactions among the HCCH motif, the BC box, and downstream residues in Vif. Mutation of residues near the PPLP motif (S165 and V166) affected the oligomeric properties of Vif and weakened the ability of Vif to bind and induce the degradation of APOBEC3G. We propose that Vif oligomerization may represent a mechanism for regulating interactions with APOBEC3G.

  6. Peptide Inhibitors of HIV-1 Virus Infection Based on Cullin-5

    Institute of Scientific and Technical Information of China (English)

    ZHU Ke-tong; ZHANG Xi-zhen; LOU Chao-ping; GUO Bo; DU Juan; WANG Xiao-dan; WU Yong-ge; KONG Wei; YU Xiang-hui

    2008-01-01

    Virion infectivity factor(Vif) is one of the six accessory proteins of HIV-1 and is necessary for viral infectivity. Human Apolipoprotein B editing complex protein 3G(h-APOBEC3G) is a cytidine deaminase only expressed in "nonpermissive" cells and exhibits virus suppressive activity. With the aid of a Cullin-5 E3 ligase, Vif induces h-APOBEC3G degradation and with the destruction of this ligase, Vif is functionally inactive. Therefore, it is expected that blocking this E3 pathway would be a new therapeutic strategy against HIV-1 infection. In this article, the authors' took sequence alignment of the N-termini of Cullin-5 and three other members of the Cullin protein family,respectively. A set of small peptides has been synthesized based on the sequence comparison results and possible Vif-Cullin-5 interaction domains. Moreover, it has been demonstrated that several peptides can reduce virus infectivity in "nonpermissive" cells with a dose-responsive manner, but not in "permissive" cells. The results also indicate that the loss of viral infectivity may be because of the increase of APOBEC3G amount in the peptide-treated cells. It is concluded that peptides derived from Cullin-5 can block the APOBEC3G degradation induced by Vif and suppress HIV-1 infectivity. Therefore this study starts a novel strategy for the development of a new HIV-1 inhibitor.

  7. Differential requirements for HIV-1 Vif-mediated APOBEC3G degradation and RUNX1-mediated transcription by core binding factor beta.

    Science.gov (United States)

    Du, Juan; Zhao, Ke; Rui, Yajuan; Li, Peng; Zhou, Xiaohong; Zhang, Wenyan; Yu, Xiao-Fang

    2013-02-01

    Core binding factor beta (CBFβ), a transcription regulator through RUNX binding, was recently reported critical for Vif function. Here, we mapped the primary functional domain important for Vif function to amino acids 15 to 126 of CBFβ. We also revealed that different lengths and regions are required for CBFβ to assist Vif or RUNX. The important interaction domains that are uniquely required for Vif but not RUNX function represent novel targets for the development of HIV inhibitors.

  8. Suppression of APOBEC3-mediated restriction of HIV-1 by Vif.

    Science.gov (United States)

    Feng, Yuqing; Baig, Tayyba T; Love, Robin P; Chelico, Linda

    2014-01-01

    The APOBEC3 restriction factors are a family of deoxycytidine deaminases that are able to suppress replication of viruses with a single-stranded DNA intermediate by inducing mutagenesis and functional inactivation of the virus. Of the seven human APOBEC3 enzymes, only APOBEC3-D, -F, -G, and -H appear relevant to restriction of HIV-1 in CD4+ T cells and will be the focus of this review. The restriction of HIV-1 occurs most potently in the absence of HIV-1 Vif that induces polyubiquitination and degradation of APOBEC3 enzymes through the proteasome pathway. To restrict HIV-1, APOBEC3 enzymes must be encapsidated into budding virions. Upon infection of the target cell during reverse transcription of the HIV-1 RNA into (-)DNA, APOBEC3 enzymes deaminate cytosines to form uracils in single-stranded (-)DNA regions. Upon replication of the (-)DNA to (+)DNA, the HIV-1 reverse transcriptase incorporates adenines opposite to the uracils thereby inducing C/G to T/A mutations that can functionally inactivate HIV-1. APOBEC3G is the most studied APOBEC3 enzyme and it is known that Vif attempts to thwart APOBEC3 function not only by inducing its proteasomal degradation but also by several degradation-independent mechanisms, such as inhibiting APOBEC3G virion encapsidation, mRNA translation, and for those APOBEC3G molecules that still become virion encapsidated, Vif can inhibit APOBEC3G mutagenic activity. Although most Vif variants can induce efficient degradation of APOBEC3-D, -F, and -G, there appears to be differential sensitivity to Vif-mediated degradation for APOBEC3H. This review examines APOBEC3-mediated HIV restriction mechanisms, how Vif acts as a substrate receptor for a Cullin5 ubiquitin ligase complex to induce degradation of APOBEC3s, and the determinants and functional consequences of the APOBEC3 and Vif interaction from a biological and biochemical perspective.

  9. Suppression of APOBEC3-mediated restriction of HIV-1 by Vif

    Directory of Open Access Journals (Sweden)

    Yuqing eFeng

    2014-08-01

    Full Text Available The APOBEC3 restriction factors are a family of deoxycytidine deaminases that are able to suppress replication of viruses with a single-stranded DNA intermediate by inducing mutagenesis and functional inactivation of the virus. Of the seven human APOBEC3 enzymes, only APOBEC3-D, -F, -G, and -H appear relevant to restriction of HIV-1 in CD4+ T cells and will be the focus of this review. The restriction of HIV-1 occurs most potently in the absence of HIV-1 Vif that induces polyubiquitination and degradation of APOBEC3 enzymes through the proteasome pathway. To restrict HIV-1, APOBEC3 enzymes must be encapsidated into budding virions. Upon infection of the target cell during reverse transcription of the HIV-1 RNA into (-DNA APOBEC3 enzymes deaminate cytosines to forms uracils in single-stranded (- DNA regions. Upon replication of the (-DNA to (+DNA, the HIV-1 reverse transcriptase incorporates adenines opposite the uracils thereby inducing C/G to T/A mutations that can functionally inactivate HIV-1. APOBEC3G is the most studied APOBEC3 enzyme and it is known that Vif attempts to thwart APOBEC3 function not only by inducing its proteasomal degradation but by several degradation-independent mechanisms such as inhibiting APOBEC3G virion encapsidation, mRNA translation, and for those APOBEC3G molecules that still become virion encapsidated, Vif can inhibit APOBEC3G mutagenic activity. Although most Vif variants can induce efficient degradation of APOBEC3-D, -F, and -G, there appears to be differential sensitivity to Vif-mediated degradation for APOBEC3H. This review examines APOBEC3-mediated HIV restriction mechanisms, how Vif acts as a substrate receptor for a Cullin5 ubiquitin ligase complex to induce degradation of APOBEC3s, and the determinants and functional consequences of the APOBEC3 and Vif interaction from a biological and biochemical perspective.

  10. Convergence and divergence in the evolution of the APOBEC3G-Vif interaction reveal ancient origins of simian immunodeficiency viruses.

    Science.gov (United States)

    Compton, Alex A; Emerman, Michael

    2013-01-01

    Naturally circulating lentiviruses are abundant in African primate species today, yet their origins and history of transmitting between hosts remain obscure. As a means to better understand the age of primate lentiviruses, we analyzed primate genomes for signatures of lentivirus-driven evolution. Specifically, we studied the adaptive evolution of host restriction factor APOBEC3G (A3G) in Old World Monkey (OWM) species. We find recurrent mutation of A3G in multiple primate lineages at sites that determine susceptibility to antagonism by the lentiviral accessory protein Vif. Using a broad panel of SIV Vif isolates, we demonstrate that natural variation in OWM A3G confers resistance to Vif-mediated degradation, suggesting that adaptive variants of the host factor were selected upon exposure to pathogenic lentiviruses at least 5-6 million years ago (MYA). Furthermore, in members of the divergent Colobinae subfamily of OWM, a multi-residue insertion event in A3G that arose at least 12 MYA blocks the activity of Vif, suggesting an even more ancient origin of SIV. Moreover, analysis of the lentiviruses associated with Colobinae monkeys reveal that the interface of the A3G-Vif interaction has shifted and given rise to a second genetic conflict. Our analysis of virus-driven evolution describes an ancient yet ongoing genetic conflict between simian primates and lentiviruses on a million-year time scale.

  11. Interaction of human immunodeficiency virus type 1 Vif with APOBEC3G is not dependent on serine/threonine phosphorylation status.

    Science.gov (United States)

    Kopietz, Ferdinand; Jaguva Vasudevan, Ananda Ayyappan; Krämer, Melanie; Muckenfuss, Heide; Sanzenbacher, Ralf; Cichutek, Klaus; Flory, Egbert; Münk, Carsten

    2012-11-01

    The human immunodeficiency virus type 1 accessory protein Vif is important for viral infectivity because it counteracts the antiviral protein APOBEC3G (A3G). ³²P metabolic labelling of stimulated cells revealed in vivo phosphorylation of the control protein, whereas no serine/threonine phosphorylation was detected for Vif or the A3G protein. These data were confirmed by in vitro kinase assays using active recombinant kinase. Mitogen-activated protein kinase/extracellular signal-regulated kinase 2 efficiently phosphorylated its target ELK, but failed to phosphorylate Vif. Putative serine/threonine phosphorylation point mutations in Vif (T96, S144, S165, T188) using single-round infection assays demonstrated that these mutations did not alter Vif activity, with the exception of Vif.T96E. Interestingly, T96E and not T96A was functionally impaired, indicating that this residue is critical for Vif-A3G physical interaction and activity. Our data suggest that Vif and A3G are not serine/threonine phosphorylated in human cells and phosphorylation is not linked to their functional activities.

  12. Complex positive selection pressures drive the evolution of HIV-1 with different co-receptor tropisms

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    HIV-1 co-receptor tropism is central for understanding the transmission and pathogenesis of HIV-1 infection. We performed a genome-wide comparison between the adaptive evolution of R5 and X4 variants from HIV-1 subtypes B and C. The results showed that R5 and X4 variants experienced differential evolutionary patterns and different HIV-1 genes encountered various positive selection pressures, suggesting that complex selection pressures are driving HIV-1 evolution. Compared with other hypervariable regions of Gp120, significantly more positively selected sites were detected in the V3 region of subtype B X4 variants, V2 region of subtype B R5 variants, and V1 and V4 regions of subtype C X4 variants, indicating an association of positive selection with co-receptor recognition/binding. Intriguingly, a significantly higher proportion (33.3% and 55.6%, P<0.05) of positively selected sites were identified in the C3 region than other conserved regions of Gp120 in all the analyzed HIV-1 variants, indicating that the C3 region might be more important to HIV-1 adaptation than previously thought. Approximately half of the positively selected sites identified in the env gene were identical between R5 and X4 variants. There were three common positively selected sites (96, 113 and 281) identified in Gp41 of all X4 and R5 variants from subtypes B and C. These sites might not only suggest a functional importance in viral survival and adaptation, but also imply a potential cross-immunogenicity between HIV-1 R5 and X4 variants, which has important implications for AIDS vaccine development.

  13. HIV-1 accessory proteins: Vpu and Vif.

    Science.gov (United States)

    Andrew, Amy; Strebel, Klaus

    2014-01-01

    HIV-1 Vif and Vpu are accessory factors involved in late stages of viral replication. Vif regulates viral infectivity by preventing virion incorporation of APOBEC3G and other members of the family of cytidine deaminases, while Vpu causes degradation of CD4 and promotes virus release by functionally inactivating the host factor BST-2. This chapter described techniques used for the characterization of Vif and Vpu and their functional interaction with host factors. Many of the techniques are, however, applicable to the functional analysis of other viral proteins.

  14. Lower HIV provirus levels are associated with more APOBEC3G protein in blood resting memory CD4+ T lymphocytes of controllers in vivo.

    Directory of Open Access Journals (Sweden)

    Mariapia De Pasquale

    Full Text Available Immunodeficiency does not progress for prolonged periods in some HLA B57- and/or B27-positive subjects with human immunodeficiency virus type 1 (HIV infection, even in the absence of antiretroviral therapy (ART. These "controllers" have fewer HIV provirus-containing peripheral blood mononuclear cells than "non-controller" subjects, but lymphocytes that harbor latent proviruses were not specifically examined in studies to date. Provirus levels in resting memory cells that can serve as latent reservoirs of HIV in blood were compared here between controllers and ART-suppressed non-controllers. APOBEC3G (A3G, a cellular factor that blocks provirus formation at multiple steps if not antagonized by HIV virion infectivity factor (Vif, was also studied. HLA-linked HIV control was associated with less provirus and more A3G protein in resting CD4+ T central memory (Tcm and effector memory (Tem lymphocytes (provirus: p = 0.01 for Tcm and p = 0.02 for Tem; A3G: p = 0.02 for Tcm and p = 0.02 for Tem. Resting memory T cells with the highest A3G protein levels (>0.5 RLU per unit of actin had the lowest levels of provirus (<1,000 copies of DNA per million cells in vivo (p = 0.03, Fisher's exact test. Using two different experimental approaches, Vif-positive viruses with more A3G were found to have decreased virion infectivity ex vivo. These results raise the hypothesis that HIV control is associated with increased cellular A3G that may be packaged into Vif-positive virions to add that mode of inhibition of provirus formation to previously described adaptive immune mechanisms for HIV control.

  15. Endogenous origins of HIV-1 G-to-A hypermutation and restriction in the nonpermissive T cell line CEM2n.

    Directory of Open Access Journals (Sweden)

    Eric W Refsland

    Full Text Available The DNA deaminase APOBEC3G converts cytosines to uracils in retroviral cDNA, which are immortalized as genomic strand G-to-A hypermutations by reverse transcription. A single round of APOBEC3G-dependent mutagenesis can be catastrophic, but evidence suggests that sublethal levels contribute to viral genetic diversity and the associated problems of drug resistance and immune escape. APOBEC3G exhibits an intrinsic preference for the second cytosine in a 5'CC dinucleotide motif leading to 5'GG-to-AG mutations. However, an additional hypermutation signature is commonly observed in proviral sequences from HIV-1 infected patients, 5'GA-to-AA, and it has been attributed controversially to one or more of the six other APOBEC3 deaminases. An unambiguous resolution of this problem has been difficult to achieve, in part due to dominant effects of protein over-expression. Here, we employ gene targeting to dissect the endogenous APOBEC3 contribution to Vif-deficient HIV-1 restriction and hypermutation in a nonpermissive T cell line CEM2n. We report that APOBEC3G-null cells, as predicted from previous studies, lose the capacity to inflict 5'GG-to-AG mutations. In contrast, APOBEC3F-null cells produced viruses with near-normal mutational patterns. Systematic knockdown of other APOBEC3 genes in an APOBEC3F-null background revealed a significant contribution from APOBEC3D in promoting 5'GA-to-AA hypermutations. Furthermore, Vif-deficient HIV-1 restriction was strong in parental CEM2n and APOBEC3D-knockdown cells, partially alleviated in APOBEC3G- or APOBEC3F-null cells, further alleviated in APOBEC3F-null/APOBEC3D-knockdown cells, and alleviated to the greatest extent in APOBEC3F-null/APOBEC3G-knockdown cells revealing clear redundancy in the HIV-1 restriction mechanism. We conclude that endogenous levels of APOBEC3D, APOBEC3F, and APOBEC3G combine to restrict Vif-deficient HIV-1 and cause the hallmark dinucleotide hypermutation patterns in CEM2n. Primary T

  16. A novel HIV-1 restriction factor that is biologically distinct from APOBEC3 cytidine deaminases in a human T cell line CEM.NKR

    Directory of Open Access Journals (Sweden)

    Zhou Tao

    2009-04-01

    Full Text Available Abstract Background Isolation of novel retroviral restriction factors will open new avenues for anti-HIV/AIDS treatment. Although HIV-1 replication is restricted by APOBEC3G/APOBEC3F, TRIM5α, and CD317, none defend HIV-1 infection under natural conditions. Previously, we demonstrated a host factor from the human T cell line CEM.NKR that potently restricted wild-type HIV-1 replication. Interestingly, this restriction resembled the APOBEC3G/APOBEC3F pattern in that viral replication was inhibited from the second round of replication cycle at a post-entry step. Results Here, we further characterized this factor and found it distinguishable from the known anti-HIV APOBEC3 proteins. Although CEM.NKR cells expressed both APOBEC3G and APOBEC3F, their levels were at least 10 or 4-fold lower than those in H9 cells, and importantly, Vif effectively neutralized their activity. Among eight subclones isolated from CEM.NKR cells, one was relatively permissive, four were semi-permissive, and three were completely non-permissive for HIV-1 replication. When the levels of APOBEC3 expression were determined, all these clones retained similar low levels of APOBEC3DE, APOBEC3F, APOBEC3G and APOBEC3H expression, and no APOBEC3B expression was detected. Since the vif from SIVmac can effectively neutralize APOBEC3B and APOBEC3H, recombinant HIV-1 expressing this SIV gene were created. However, these viruses still failed to replicate in CEM.NKR cells. We also confirmed that HIV-1 restriction in CEM.NKR was not due to a loss of calnexin expression. Conclusion Taken together, these results not only demonstrate that all these aforementioned anti-HIV APOBEC3 proteins do not contribute to this HIV-1 restriction, but also shed light on a novel and potent HIV-1 inhibitor in CEM.NKR cells.

  17. HIV-1 Vpr促进Vif和APOBEC3G蛋白表达的研究%Enhanced protein production of Vif and APOBEC3G by HIV-1 Vpr

    Institute of Scientific and Technical Information of China (English)

    李林; 梁栋; 李敬云; 赵玉琪

    2008-01-01

    目的 观察人获得性免疫缺陷病毒蛋白Vpr对Vif蛋白和APOBEC3G蛋白表达水平的影响.方法 使用电转化法将携带Vif基因的酵母表达载体转化到裂殖酵母中,使用脂质体转染法将表达Vif蛋白、APOBEC3G蛋白的哺乳动物表达载体转染到可诱导稳定表达Vpr蛋白的哺乳动物HEK293细胞中;使用Western Blot方法检测目标蛋白表达水平的变化.结果 在裂殖酵母和哺乳动物细胞中,Vpr蛋白的表达能够提高细胞内的Vif蛋白的表达水平,在哺乳动物细胞中,Vpr蛋白对APOBEC3G蛋白的表达亦有促进作用,Vpr蛋白引起的Vif蛋白量的提高并没有导致APOBEC3G蛋白的减少.结论 Vpr蛋白具有调节细胞内蛋白表达的功能.

  18. APOBEC3D and APOBEC3F potently promote HIV-1 diversification and evolution in humanized mouse model.

    Directory of Open Access Journals (Sweden)

    Kei Sato

    2014-10-01

    Full Text Available Several APOBEC3 proteins, particularly APOBEC3D, APOBEC3F, and APOBEC3G, induce G-to-A hypermutations in HIV-1 genome, and abrogate viral replication in experimental systems, but their relative contributions to controlling viral replication and viral genetic variation in vivo have not been elucidated. On the other hand, an HIV-1-encoded protein, Vif, can degrade these APOBEC3 proteins via a ubiquitin/proteasome pathway. Although APOBEC3 proteins have been widely considered as potent restriction factors against HIV-1, it remains unclear which endogenous APOBEC3 protein(s affect HIV-1 propagation in vivo. Here we use a humanized mouse model and HIV-1 with mutations in Vif motifs that are responsible for specific APOBEC3 interactions, DRMR/AAAA (4A or YRHHY/AAAAA (5A, and demonstrate that endogenous APOBEC3D/F and APOBEC3G exert strong anti-HIV-1 activity in vivo. We also show that the growth kinetics of 4A HIV-1 negatively correlated with the expression level of APOBEC3F. Moreover, single genome sequencing analyses of viral RNA in plasma of infected mice reveal that 4A HIV-1 is specifically and significantly diversified. Furthermore, a mutated virus that is capable of using both CCR5 and CXCR4 as entry coreceptor is specifically detected in 4A HIV-1-infected mice. Taken together, our results demonstrate that APOBEC3D/F and APOBEC3G fundamentally work as restriction factors against HIV-1 in vivo, but at the same time, that APOBEC3D and APOBEC3F are capable of promoting viral diversification and evolution in vivo.

  19. Driving HIV-1 into a Vulnerable Corner by Taking Advantage of Viral Adaptation and Evolution

    Science.gov (United States)

    Harada, Shigeyoshi; Yoshimura, Kazuhisa

    2017-01-01

    Anti-retroviral therapy (ART) is crucial for controlling human immunodeficiency virus type-1 (HIV-1) infection. Recently, progress in identifying and characterizing highly potent broadly neutralizing antibodies has provided valuable templates for HIV-1 therapy and vaccine design. Nevertheless, HIV-1, like many RNA viruses, exhibits genetically diverse populations known as quasispecies. Evolution of quasispecies can occur rapidly in response to selective pressures, such as that exerted by ART and the immune system. Hence, rapid viral evolution leading to drug resistance and/or immune evasion is a significant barrier to the development of effective HIV-1 treatments and vaccines. Here, we describe our recent investigations into evolutionary pressure exerted by anti-retroviral drugs and monoclonal neutralizing antibodies (NAbs) on HIV-1 envelope sequences. We also discuss sensitivities of HIV-1 escape mutants to maraviroc, a CCR5 inhibitor, and HIV-1 sensitized to NAbs by small-molecule CD4-mimetic compounds. These studies help to develop an understanding of viral evolution and escape from both anti-retroviral drugs and the immune system, and also provide fundamental insights into the combined use of NAbs and entry inhibitors. These findings of the adaptation and evolution of HIV in response to drug and immune pressure will inform the development of more effective antiviral therapeutic strategies. PMID:28360890

  20. Evolutionarily conserved pressure for the existence of distinct G2/M cell cycle arrest and A3H inactivation functions in HIV-1 Vif.

    Science.gov (United States)

    Zhao, Ke; Du, Juan; Rui, Yajuan; Zheng, Wenwen; Kang, Jian; Hou, Jingwei; Wang, Kang; Zhang, Wenyan; Simon, Viviana A; Yu, Xiao-Fang

    2015-01-01

    HIV-1 Vif assembles the Cul5-EloB/C E3 ubiquitin ligase to induce proteasomal degradation of the cellular antiviral APOBEC3 proteins. Detailed structural studies have confirmed critical functional domains in Vif that we have previously identified as important for the interaction of EloB/C, Cul5, and CBFβ. However, the mechanism by which Vif recognizes substrates remains poorly understood. Specific regions of Vif have been identified as being responsible for binding and depleting APOBEC3G and APOBEC3F. Interestingly, we have now identified distinct yet overlapping domains that are required for HIV-1 Vif-mediated G2/M-phase cell cycle arrest and APOBEC3H degradation, but not for the inactivation of APOBEC3G or APOBEC3F. Surprisingly, Vif molecules from primary HIV-1 variants that caused G2/M arrest were unable to inactivate APOBEC3H; on the other hand, HIV-1 Vif variants that could inactivate APOBEC3H were unable to induce G2/M arrest. All of these Vif variants still maintained the ability to inactivate APOBEC3G/F. Thus, primary HIV-1 variants have evolved to possess distinct functional activities that allow them to suppress APOBEC3H or cause G2 cell cycle arrest, using mutually exclusive interface domains. APOBEC3H depletion and G2 arrest are apparently evolutionary selected features that cannot co-exist on a single Vif molecule. The existence and persistence of both types of HIV-1 Vif variant suggests the importance of APOBEC3H suppression and cell cycle regulation for HIV-1's survival in vivo.

  1. HIV-1 Vif, APOBEC, and Intrinsic Immunity

    Directory of Open Access Journals (Sweden)

    Strebel Klaus

    2008-06-01

    Full Text Available Abstract Members of the APOBEC family of cellular cytidine deaminases represent a recently identified group of proteins that provide immunity to infection by retroviruses and protect the cell from endogenous mobile retroelements. Yet, HIV-1 is largely immune to the intrinsic antiviral effects of APOBEC proteins because it encodes Vif (viral infectivity factor, an accessory protein that is critical for in vivo replication of HIV-1. In the absence of Vif, APOBEC proteins are encapsidated by budding virus particles and either cause extensive cytidine to uridine editing of negative sense single-stranded DNA during reverse transcription or restrict virus replication through deaminase-independent mechanisms. Thus, the primary function of Vif is to prevent encapsidation of APOBEC proteins into viral particles. This is in part accomplished by the ability of Vif to induce the ubiquitin-dependent degradation of some of the APOBEC proteins. However, Vif is also able to prevent encapsidation of APOBEC3G and APOBEC3F through degradation-independent mechanism(s. The goal of this review is to recapitulate current knowledge of the functional interaction of HIV-1 and its Vif protein with the APOBEC3 subfamily of proteins and to summarize our present understanding of the mechanism of APOBEC3-dependent retrovirus restriction.

  2. The variances of Sp1 and NF-κB elements correlate with the greater capacity of Chinese HIV-1 B′-LTR for driving gene expression

    OpenAIRE

    2016-01-01

    The 5′ end of HIV-1 long terminal repeat (LTR) serves as a promoter that plays an essential role in driving viral gene transcription. Manipulation of HIV-1 LTR provides a potential therapeutic strategy for suppressing viral gene expression or excising integrated provirus. Subtype-specific genetic diversity in the LTR region has been observed. The minor variance of LTR, particularly in the transcription factor binding sites, can have a profound impact on its activity. However, the LTR profiles...

  3. Demonstration of a novel HIV-1 restriction phenotype from a human T cell line.

    Directory of Open Access Journals (Sweden)

    Yanxing Han

    Full Text Available BACKGROUND: Although retroviruses may invade host cells, a productive infection can be established only after the virus counteracts inhibition from different types of host restriction factors. Fv1, APOBEC3G/F, TRIM5alpha, ZAP, and CD317 inhibit the replication of different retroviruses by interfering with viral uncoating, reverse transcription, nuclear import, RNA stability, and release. In humans, although APOBEC3G/3F and CD317 block HIV-1 replication, their antiviral activities are neutralized by viral proteins Vif and Vpu. So far, no human gene has been found to effectively block wild type HIV-1 replication under natural condition. Thus, identification of such a gene product would be of great medical importance for the development of HIV therapies. METHOD AND FINDINGS: In this study, we discovered a new type of host restriction against the wild type HIV-1 from a CD4/CXCR4 double-positive human T cell line. We identified a CEM-derived cell line (CEM.NKR that is highly resistant to productive HIV-1 infection. Viral production was reduced by at least 1000-fold when compared to the other permissive human T cell lines such as H9, A3.01, and CEM-T4. Importantly, this resistance was evident at extremely high multiplicity of infection. Further analyses demonstrated that HIV-1 could finish the first round of replication in CEM.NKR cells, but the released virions were poorly infectious. These virions could enter the target cells, but failed to initiate reverse transcription. Notably, this restriction phenotype was also present in CEM.NKR and 293T heterokaryons. CONCLUSIONS: These results clearly indicate that CEM.NKR cells express a HIV inhibitory gene(s. Further characterization of this novel gene product(s will reveal a new antiretroviral mechanism that directly inactivates wild type HIV-1.

  4. Roles of HIV-1 auxiliary proteins in viral pathogenesis and host-pathogen interactions

    Institute of Scientific and Technical Information of China (English)

    Lin; LI; Hai; Shan; LI; C.David; PAUZA; Michael; BUKRINSKY; Richard; Y; ZHAO

    2005-01-01

    Active host-pathogen interactions take place during infection of human immunodeficiency virus type 1 (HIV-1).Outcomes of these interactions determine the efficiency of viral infection and subsequent disease progression. HIV-infected cells respond to viral invasion with various defensive strategies such as innate, cellular and humoral immune antiviral mechanisms. On the other hand, the virus has also developed various offensive tactics to suppress these host cellular responses. Among many of the viral offensive strategies, HIV- 1 viral auxiliary proteins (Tat, Rev, Nef, Vif, Vpr and Vpu) play important roles in the host-pathogen interaction and thus have significant impacts on the outcome of HIV infection. One of the best examples is the interaction of Vif with a host cytidine deaminase APOBEC3G. Although specific roles of other auxiliary proteins are not as well described as Vif-APOBEC3G interaction, it is the goal of this brief review to summarize some of the preliminary findings with the hope to stimulate further discussion and investigation in this exhilarating area of research.

  5. The CD16+ monocyte subset is more permissive to infection and preferentially harbors HIV-1 in vivo.

    Science.gov (United States)

    Ellery, Philip J; Tippett, Emma; Chiu, Ya-Lin; Paukovics, Geza; Cameron, Paul U; Solomon, Ajantha; Lewin, Sharon R; Gorry, Paul R; Jaworowski, Anthony; Greene, Warner C; Sonza, Secondo; Crowe, Suzanne M

    2007-05-15

    HIV-1 persists in peripheral blood monocytes in individuals receiving highly active antiretroviral therapy (HAART) with viral suppression, despite these cells being poorly susceptible to infection in vitro. Because very few monocytes harbor HIV-1 in vivo, we considered whether a subset of monocytes might be more permissive to infection. We show that a minor CD16+ monocyte subset preferentially harbors HIV-1 in infected individuals on HAART when compared with the majority of monocytes (CD14highCD16-). We confirmed this by in vitro experiments showing that CD16+ monocytes were more susceptible to CCR5-using strains of HIV-1, a finding that is associated with higher CCR5 expression on these cells. CD16+ monocytes were also more permissive to infection with a vesicular stomatitis virus G protein-pseudotyped reporter strain of HIV-1 than the majority of monocytes, suggesting that they are better able to support HIV-1 replication after entry. Consistent with this observation, high molecular mass complexes of apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G (APOBEC3G) were observed in CD16+ monocytes that were similar to those observed in highly permissive T cells. In contrast, CD14highCD16- monocytes contained low molecular mass active APOBEC3G, suggesting this is a mechanism of resistance to HIV-1 infection in these cells. Collectively, these data show that CD16+ monocytes are preferentially susceptible to HIV-1 entry, more permissive for replication, and constitute a continuing source of viral persistence during HAART.

  6. The variances of Sp1 and NF-κB elements correlate with the greater capacity of Chinese HIV-1 B′-LTR for driving gene expression

    Science.gov (United States)

    Qu, Di; Li, Chuan; Sang, Feng; Li, Qiang; Jiang, Zhi-Qiang; Xu, Li-Ran; Guo, Hui-Jun; Zhang, Chiyu; Wang, Jian-Hua

    2016-01-01

    The 5′ end of HIV-1 long terminal repeat (LTR) serves as a promoter that plays an essential role in driving viral gene transcription. Manipulation of HIV-1 LTR provides a potential therapeutic strategy for suppressing viral gene expression or excising integrated provirus. Subtype-specific genetic diversity in the LTR region has been observed. The minor variance of LTR, particularly in the transcription factor binding sites, can have a profound impact on its activity. However, the LTR profiles from major endemic Chinese subtypes are not well characterized. Here, by characterizing the sequences and functions of LTRs from endemic Chinese HIV-1 subtypes, we showed that nucleotide variances of Sp1 core promoter and NF-κB element are associated with varied LTR capacity for driving viral gene transcription. The greater responsiveness of Chinese HIV-1 B′-LTR for driving viral gene transcription upon stimulation is associated with an increased level of viral reactivation. Moreover, we demonstrated that the introduction of CRISPR/dead Cas9 targeting Sp1 or NF-κB element suppressed viral gene expression. Taken together, our study characterized LTRs from endemic HIV-1 subtypes in China and suggests a potential target for the suppression of viral gene expression and a novel strategy that facilitates the accomplishment of a functional cure. PMID:27698388

  7. 载脂蛋白B mRNA编辑酶催化多肽样3G在不同慢性乙型肝炎患者中的表达及其细胞内定位%Expression and subcellular localization of APOBEC3G in peripheral blood mononuclear cells and liver tissues of chronic HBV patients

    Institute of Scientific and Technical Information of China (English)

    陈辉; 王鲁文; 褚小刚; 严少南; 龚作炯

    2010-01-01

    Objective To study the expression level and intracellular localization of APOBEC3G in peripheral blood mononuclear cells (PBMCs) andliver tissues of chronic HBV patients. Methods The expression level and intracellular localization of APOBEC3G in PBMCs and liver tissues were detected using the western blot and confocal laser scanning microscope (CLSM). Results Western-blot showed that the expression level of APOBEC3G in PBMCs of healthy controls was very low. The relative expression levels of APOBEC3G in PBMC of patients with chronic hepatitis B, chronic severe hepatitis, liver cirrhosis, or liver cancer were 4.12±0.21, 4.07± 0.28, 4.16± 0.36 or 4.21±0.39 respectively, which were higher than that in the healthy controls. However, there was no significant difference in APOBEC3G expression among differ-ent chronic HBV patients (q = 0.931, 0.744, 1.675, 1.675, 2.606 or 0.931, respectively, all P values >0.05). In addition, there was no significant difference on APOBEC3G in liver tissues between chronic hepatitis B patients and bepatocellular carcinoma patients (4.40 ± 0.34 vs 4.34 ± 0.43, q = 0.588, P > 0.05). CLSM indicated that the localization of APOBEC3G protein was in cytoplasm of PBMCs and hepatoeytes. Conclu-sion APOBEC3G is upregulated in the PBMCs of chronic hepatitis B patients.%目的 观察载脂蛋白B mRNA编辑酶催化多肽样3G(APOBEC3G)在不同慢性乙型肝炎病毒(HBV)感染类型患者的外周血单个核细胞(PBMC)及肝组织中的表达水平及其细胞内定位.方法 用Western blot及激光扫描共聚焦显微镜,以健康人为对照,检测不同慢性HBV感染类型患者(慢性乙型肝炎、慢性乙型重型肝炎、肝炎肝硬化、HBV相关性肝癌)的PBMC及肝组织中APOBEC3G的表达状况及其亚细胞定位.多组比较采用方差分析,两两比较采用q检验.结果 Western blot结果显示,健康人PBMC中APOBEC3G表达水平极低,慢性乙型肝炎、慢性乙型重型肝炎、肝炎肝硬化

  8. Crystal structure of the DNA cytosine deaminase APOBEC3F: the catalytically active and HIV-1 Vif-binding domain.

    Science.gov (United States)

    Bohn, Markus-Frederik; Shandilya, Shivender M D; Albin, John S; Kouno, Takahide; Anderson, Brett D; McDougle, Rebecca M; Carpenter, Michael A; Rathore, Anurag; Evans, Leah; Davis, Ahkillah N; Zhang, Jingying; Lu, Yongjian; Somasundaran, Mohan; Matsuo, Hiroshi; Harris, Reuben S; Schiffer, Celia A

    2013-06-04

    Human APOBEC3F is an antiretroviral single-strand DNA cytosine deaminase, susceptible to degradation by the HIV-1 protein Vif. In this study the crystal structure of the HIV Vif binding, catalytically active, C-terminal domain of APOBEC3F (A3F-CTD) was determined. The A3F-CTD shares structural motifs with portions of APOBEC3G-CTD, APOBEC3C, and APOBEC2. Residues identified to be critical for Vif-dependent degradation of APOBEC3F all fit within a predominantly negatively charged contiguous region on the surface of A3F-CTD. Specific sequence motifs, previously shown to play a role in Vif susceptibility and virion encapsidation, are conserved across APOBEC3s and between APOBEC3s and HIV-1 Vif. In this structure these motifs pack against each other at intermolecular interfaces, providing potential insights both into APOBEC3 oligomerization and Vif interactions.

  9. Identification of Specific Determinants of Human APOBEC3F, APOBEC3C, and APOBEC3DE and African Green Monkey APOBEC3F That Interact with HIV-1 Vif ▿

    OpenAIRE

    Smith, Jessica L.; Pathak, Vinay K.

    2010-01-01

    Human APOBEC3F (hA3F) and human APOBEC3G (hA3G) are potent anti-human immunodeficiency virus (anti-HIV) host factors that suppress viral replication by hypermutating the viral genome, inhibiting reverse transcription, and hindering integration. To overcome hA3F and hA3G, HIV-1 encodes Vif, which binds and targets these host proteins for proteasomal degradation. Previously, we reported that the hA3F-Vif interactions that lead to hA3F degradation are located in the region comprising amino acids...

  10. MDM2 is a novel E3 ligase for HIV-1 Vif

    Directory of Open Access Journals (Sweden)

    Tomonaga Mitsunori

    2009-01-01

    Full Text Available Abstract The human immunodeficiency virus type 1 (HIV-1 Vif plays a crucial role in the viral life cycle by antagonizing a host restriction factor APOBEC3G (A3G. Vif interacts with A3G and induces its polyubiquitination and subsequent degradation via the formation of active ubiquitin ligase (E3 complex with Cullin5-ElonginB/C. Although Vif itself is also ubiquitinated and degraded rapidly in infected cells, precise roles and mechanisms of Vif ubiquitination are largely unknown. Here we report that MDM2, known as an E3 ligase for p53, is a novel E3 ligase for Vif and induces polyubiquitination and degradation of Vif. We also show the mechanisms by which MDM2 only targets Vif, but not A3G that binds to Vif. MDM2 reduces cellular Vif levels and reversely increases A3G levels, because the interaction between MDM2 and Vif precludes A3G from binding to Vif. Furthermore, we demonstrate that MDM2 negatively regulates HIV-1 replication in non-permissive target cells through Vif degradation. These data suggest that MDM2 is a regulator of HIV-1 replication and might be a novel therapeutic target for anti-HIV-1 drug.

  11. The APOBEC3C crystal structure and the interface for HIV-1 Vif binding.

    Science.gov (United States)

    Kitamura, Shingo; Ode, Hirotaka; Nakashima, Masaaki; Imahashi, Mayumi; Naganawa, Yuriko; Kurosawa, Teppei; Yokomaku, Yoshiyuki; Yamane, Takashi; Watanabe, Nobuhisa; Suzuki, Atsuo; Sugiura, Wataru; Iwatani, Yasumasa

    2012-10-01

    The human apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3 (APOBEC3, referred to as A3) proteins are cellular cytidine deaminases that potently restrict retrovirus replication. However, HIV-1 viral infectivity factor (Vif) counteracts the antiviral activity of most A3 proteins by targeting them for proteasomal degradation. To date, the structure of an A3 protein containing a Vif-binding interface has not been solved. Here, we report a high-resolution crystal structure of APOBEC3C and identify the HIV-1 Vif-interaction interface. Extensive structure-guided mutagenesis revealed the role of a shallow cavity composed of hydrophobic or negatively charged residues between the α2 and α3 helices. This region is distant from the DPD motif (residues 128-130) of APOBEC3G that participates in HIV-1 Vif interaction. These findings provide insight into Vif-A3 interactions and could lead to the development of new pharmacologic anti-HIV-1 compounds.

  12. Viral escape from HIV-1 neutralizing antibodies drives increased plasma neutralization breadth through sequential recognition of multiple epitopes and immunotypes.

    Directory of Open Access Journals (Sweden)

    Constantinos Kurt Wibmer

    2013-10-01

    Full Text Available Identifying the targets of broadly neutralizing antibodies to HIV-1 and understanding how these antibodies develop remain important goals in the quest to rationally develop an HIV-1 vaccine. We previously identified a participant in the CAPRISA Acute Infection Cohort (CAP257 whose plasma neutralized 84% of heterologous viruses. In this study we showed that breadth in CAP257 was largely due to the sequential, transient appearance of three distinct broadly neutralizing antibody specificities spanning the first 4.5 years of infection. The first specificity targeted an epitope in the V2 region of gp120 that was also recognized by strain-specific antibodies 7 weeks earlier. Specificity for the autologous virus was determined largely by a rare N167 antigenic variant of V2, with viral escape to the more common D167 immunotype coinciding with the development of the first wave of broadly neutralizing antibodies. Escape from these broadly neutralizing V2 antibodies through deletion of the glycan at N160 was associated with exposure of an epitope in the CD4 binding site that became the target for a second wave of broadly neutralizing antibodies. Neutralization by these CD4 binding site antibodies was almost entirely dependent on the glycan at position N276. Early viral escape mutations in the CD4 binding site drove an increase in wave two neutralization breadth, as this second wave of heterologous neutralization matured to recognize multiple immunotypes within this site. The third wave targeted a quaternary epitope that did not overlap any of the four known sites of vulnerability on the HIV-1 envelope and remains undefined. Altogether this study showed that the human immune system is capable of generating multiple broadly neutralizing antibodies in response to a constantly evolving viral population that exposes new targets as a consequence of escape from earlier neutralizing antibodies.

  13. Design, synthesis and biological evaluation of indolizine derivatives as HIV-1 VIF-ElonginC interaction inhibitors.

    Science.gov (United States)

    Huang, Wenlin; Zuo, Tao; Jin, Hongwei; Liu, Zhenming; Yang, Zhenjun; Yu, Xianghui; Zhang, Liangren; Zhang, Lihe

    2013-05-01

    The HIV-1 viral infectivity factor (VIF) protein is essential for viral replication. VIF recruits cellular ElonginB/C-Cullin5 E3 ubiquitin ligase to target the host antiviral protein APOBEC3G (A3G) for proteasomal degradation. Thus, the A3G-Vif-E3 complex represents an attractive target for the development of novel anti-HIV drugs. In this study, we describe the design and synthesis of indolizine derivatives as VIF inhibitors targeting the VIF-ElonginC interaction. Many of the synthesized compounds exhibited obvious inhibition activities of VIF-mediated A3G degradation, and 5 compounds showed improvement of activity compared to the known VIF inhibitor VEC-5 (1) with IC(50) values about 20 μM. The findings described here will be useful for the development of more potent VIF inhibitors.

  14. APOBEC3G和HIV-1病毒感染因子Vif研究最新进展

    Institute of Scientific and Technical Information of China (English)

    张文俊; 乔新华; 李泽琳; 曾毅

    2012-01-01

    固有免疫在机体抵御HIV-1感染过程中发挥重要作用.载脂蛋白B mRNA编辑酶催化多肽样蛋白(apolipoprotein B mRNA-editing enzyme catalytic polypeptide protein,APOBEC)家族的成员APOBEC3G(A3G)可以通过胞嘧啶脱氨机制抑制HIV-1的复制,发挥固有免疫的作用;病毒感染因子(virus infectivity factor,Vif)能与A3G结合并引发A3G的降解,使HIV-1的感染率增加100倍以上.该研究为以Vif-A3G为靶点的抗HIV-1药物的研究提供了新的思路.因此A3G、Vif及其相互作用机制成为HIV-1研究的热点.

  15. Interferon-α Subtypes in an Ex Vivo Model of Acute HIV-1 Infection: Expression, Potency and Effector Mechanisms.

    Directory of Open Access Journals (Sweden)

    Michael S Harper

    Full Text Available HIV-1 is transmitted primarily across mucosal surfaces and rapidly spreads within the intestinal mucosa during acute infection. The type I interferons (IFNs likely serve as a first line of defense, but the relative expression and antiviral properties of the 12 IFNα subtypes against HIV-1 infection of mucosal tissues remain unknown. Here, we evaluated the expression of all IFNα subtypes in HIV-1-exposed plasmacytoid dendritic cells by next-generation sequencing. We then determined the relative antiviral potency of each IFNα subtype ex vivo using the human intestinal Lamina Propria Aggregate Culture model. IFNα subtype transcripts from the centromeric half of the IFNA gene complex were highly expressed in pDCs following HIV-1 exposure. There was an inverse relationship between IFNA subtype expression and potency. IFNα8, IFNα6 and IFNα14 were the most potent in restricting HIV-1 infection. IFNα2, the clinically-approved subtype, and IFNα1 were both highly expressed but exhibited relatively weak antiviral activity. The relative potencies correlated with binding affinity to the type I IFN receptor and the induction levels of HIV-1 restriction factors Mx2 and Tetherin/BST-2 but not APOBEC3G, F and D. However, despite the lack of APOBEC3 transcriptional induction, the higher relative potency of IFNα8 and IFNα14 correlated with stronger inhibition of virion infectivity, which is linked to deaminase-independent APOBEC3 restriction activity. By contrast, both potent (IFNα8 and weak (IFNα1 subtypes significantly induced HIV-1 GG-to-AG hypermutation. The results unravel non-redundant functions of the IFNα subtypes against HIV-1 infection, with strong implications for HIV-1 mucosal immunity, viral evolution and IFNα-based functional cure strategies.

  16. Identification of HIV-1 Vif regions required for CBF-β interaction and APOBEC3 suppression.

    Science.gov (United States)

    Wang, Hong; Liu, Bin; Liu, Xin; Li, Zhaolong; Yu, Xiao-Fang; Zhang, Wenyan

    2014-01-01

    Human immunodeficiency virus type 1 (HIV-1) Vif requires core binding factor β (CBF-β) to degrade the host APOBEC3 restriction factors. Although a minimum domain and certain amino acids of HIV-1 Vif, including hydrophobic residues at the N-terminal, have been identified as critical sites for binding with CBF-β, other regions that potentially mediate this interaction need to be further investigated. Here, we mapped two new regions of HIV-1 Vif that are required for interaction with CBF-β by generating a series of single-site or multiple-site Vif mutants and testing their effect on the suppression of APOBEC3G (A3G) and APOBEC3F (A3F). A number of the mutants, including G84A/SIEW86-89AAAA (84/86-89), E88A/W89A (88/89), G84A, W89A, L106S and I107S in the 84GxSIEW89 and L102ADQLI107 regions, affected Vif function by disrupting CBF-β binding. These Vif mutants also had altered interactions with CUL5, since CBF-β is known to facilitate the binding of Vif to CUL5. We further showed that this effect was not due to misfolding or conformational changes in Vif, as the mutants still maintained their interactions with other factors such as ElonginB, A3G and A3F. Notably, G84D and D104A had stronger effects on the Vif-CUL5 interaction than on the Vif-CBF-β interaction, indicating that they mainly influenced the CUL5 interaction and implying that the interaction of Vif with CUL5 contributes to the binding of Vif to CBF-β. These new binding interfaces with CBF-β in HIV-1 Vif provide novel targets for the development of HIV-1 inhibitors.

  17. Cyclin F/FBXO1 interacts with HIV-1 Vif and restricts progeny virion infectivity by ubiquitination and proteasomal degradation of Vif through SCF (Cyclin F) E3 ligase machinery.

    Science.gov (United States)

    Augustine, Tracy; Chaudhary, Priyanka; Gupta, Kailash; Islam, Sehbanul; Ghosh, Payel; Santra, Manas Kumar; Mitra, Debashis

    2017-02-09

    Cyclin F, also known as FBXO1, is the largest among all cyclins which oscillates in the cell cycle like other cyclins. Apart from being a G2/M cyclin, Cyclin F functions as the substrate binding subunit of SCFCyclin F E3 ubiquitin ligase. In a gene expression analysis performed to identify novel gene modulations associated with cell cycle dysregulation during HIV-1 infection in CD4+ T cells, we observed down-regulation of Cyclin F (CCNF) gene. Later, using gene over expression and knockdown studies, we identified that Cyclin F negatively influences HIV-1 viral infectivity without any significant impact on virus production. Subsequently, we found that Cyclin F negatively regulates the expression of viral protein, Vif (Viral infectivity factor), at the protein level. We also identified a novel host-pathogen interaction between Cyclin F and Vif protein in T cells during HIV-1 infection. Mutational analysis of a Cyclin F-specific amino acid motif in the C-terminal region of Vif shows rescue of the protein from Cyclin F-mediated down-regulation. Subsequently, we have shown that Vif is a novel substrate of the SCFCyclin F E3 ligase, where Cyclin F mediates ubiquitination and proteasomal degradation of Vif through physical interaction. Finally, we have shown that Cyclin F augments APOBEC3G expression through degradation of Vif to regulate infectivity of progeny virions. Taken together, our results demonstrate Cyclin F as a novel F-box protein which functions as an intrinsic cellular regulator of HIV-1 Vif and imparts a negative regulatory effect on maintenance of viral infectivity by restoring APOBEC3G expression.

  18. Structural determinants of HIV-1 Vif susceptibility and DNA binding in APOBEC3F.

    Science.gov (United States)

    Siu, Karen K; Sultana, Azmiri; Azimi, Farshad C; Lee, Jeffrey E

    2013-01-01

    The human APOBEC3 family of DNA cytosine deaminases serves as a front-line intrinsic immune response to inhibit the replication of diverse retroviruses. APOBEC3F and APOBEC3G are the most potent factors against HIV-1. As a countermeasure, HIV-1 viral infectivity factor (Vif) targets APOBEC3s for proteasomal degradation. Here we report the crystal structure of the Vif-binding domain in APOBEC3F and a novel assay to assess Vif-APOBEC3 binding. Our results point to an amphipathic surface that is conserved in APOBEC3s as critical for Vif susceptibility in APOBEC3F. Electrostatic interactions likely mediate Vif binding. Moreover, structure-guided mutagenesis reveals a straight ssDNA-binding groove distinct from the Vif-binding site, and an 'aromatic switch' is proposed to explain DNA substrate specificities across the APOBEC3 family. This study opens new lines of inquiry that will further our understanding of APOBEC3-mediated retroviral restriction and provides an accurate template for structure-guided development of inhibitors targeting the APOBEC3-Vif axis.

  19. The role of Vif oligomerization and RNA chaperone activity in HIV-1 replication.

    Science.gov (United States)

    Batisse, Julien; Guerrero, Santiago; Bernacchi, Serena; Sleiman, Dona; Gabus, Caroline; Darlix, Jean-Luc; Marquet, Roland; Tisné, Carine; Paillart, Jean-Christophe

    2012-11-01

    The viral infectivity factor (Vif) is essential for the productive infection and dissemination of HIV-1 in non-permissive cells that involve most natural HIV-1 target cells. Vif counteracts the packaging of two cellular cytidine deaminases named APOBEC3G (A3G) and A3F by diverse mechanisms including the recruitment of an E3 ubiquitin ligase complex and the proteasomal degradation of A3G/A3F, the inhibition of A3G mRNA translation or by a direct competition mechanism. In addition, Vif appears to be an active partner of the late steps of viral replication by participating in virus assembly and Gag processing, thus regulating the final stage of virion formation notably genomic RNA dimerization and by inhibiting the initiation of reverse transcription. Vif is a small pleiotropic protein with multiple domains, and recent studies highlighted the importance of Vif conformation and flexibility in counteracting A3G and in binding RNA. In this review, we will focus on the oligomerization and RNA chaperone properties of Vif and show that the intrinsic disordered nature of some Vif domains could play an important role in virus assembly and replication. Experimental evidence demonstrating the RNA chaperone activity of Vif will be presented.

  20. Synthesis, biological evaluation and molecular docking study of N-(2-methoxyphenyl)-6-((4-nitrophenyl)sulfonyl)benzamide derivatives as potent HIV-1 Vif antagonists.

    Science.gov (United States)

    Zhou, Meng; Luo, Rong-Hua; Hou, Xue-Yan; Wang, Rui-Rui; Yan, Guo-Yi; Chen, Huan; Zhang, Rong-Hong; Shi, Jian-You; Zheng, Yong-Tang; Li, Rui; Wei, Yu-Quan

    2017-03-31

    Viral infectivity factor (Vif) is protective against APOBEC3G (A3G)-mediated viral cDNA hypermutations, and development of molecules that inhibit Vif mediated A3G degradation is a novel strategy for blocking HIV-1 replication. Through optimizations of the central ring of N-(2-methoxyphenyl)-2-((4-nitrophenyl)thio)benzamide (RN-18), we found a potent compound 12c with EC50 value of 1.54 μM, enhancing the antiviral activity more than 150-fold compared with RN-18 in nonpermissive H9 cells. 12c protected A3G from degradation by inhibiting Vif function. Besides, 12c suppressed different HIV-1 clinical strains (HIV-1KM018, HIV-1TC-1 and HIV-1WAN) and drug-resistant strains (NRTI, NNRTI, PI, and FI) with relatively high activities. Amidation of 12c with glycine gave a prodrug 13a, improving the water solubility about 2600-fold compared with 12c. Moreover, 13a inhibited the virus replication efficiently with an EC50 value of 0.228 μM. These results suggested that the prodrug 13a is a promising candidate agent for the treatment of AIDS.

  1. Differential expression of HIV-1 interfering factors in monocyte-derived macrophages stimulated with polarizing cytokines or interferons

    Science.gov (United States)

    Jiménez, Viviana Cobos; Booiman, Thijs; de Taeye, Steven W.; van Dort, Karel A.; Rits, Maarten A. N.; Hamann, Jörg; Kootstra, Neeltje A.

    2012-10-01

    HIV-1 replication in macrophages can be regulated by cytokines and infection is restricted in macrophages activated by type I interferons and polarizing cytokines. Here, we observed that the expression levels of the cellular factors Trim5α, CypA, APOBEC3G, SAMHD-1, Trim22, tetherin and TREX-1, and the anti-HIV miRNAs miR-28, miR-150, miR-223 and miR-382 was upregulated by IFN-α and IFN-β in macrophages, which may account for the inhibiting effect on viral replication and the antiviral state of these cells. Expression of these factors was also increased by IFN-γ +/- TNF-α, albeit to a lesser extent; yet, HIV-1 replication in these cells was not restricted at the level of proviral synthesis, indicating that these cellular factors only partially contribute to the observed restriction. IL-4, IL-10 or IL-32 polarization did not affect the expression of cellular factors and miRNAs, suggesting only a limited role for these cellular factors in restricting HIV-1 replication in macrophages.

  2. Target cell APOBEC3C can induce limited G-to-A mutation in HIV-1.

    Directory of Open Access Journals (Sweden)

    Khaoula Bourara

    2007-10-01

    Full Text Available The evolutionary success of primate lentiviruses reflects their high capacity to mutate and adapt to new host species, immune responses within individual hosts, and, in recent years, antiviral drugs. APOBEC3G (A3G and APOBEC3F (A3F are host cell DNA-editing enzymes that induce extensive HIV-1 mutation that severely attenuates viral replication. The HIV-1 virion infectivity factor (Vif, expressed in vivo, counteracts the antiviral activity of A3G and A3F by inducing their degradation. Other APOBECs may contribute more to viral diversity by inducing less extensive mutations allowing viral replication to persist. Here we show that in APOBEC3C (A3C-expressing cells infected with the patient-derived HIV-1 molecular clones 210WW, 210WM, 210MW, and 210MM, and the lab-adapted molecular clone LAI, viral G-to-A mutations were detected in the presence of Vif expression. Mutations occurred primarily in the GA context and were relatively infrequent, thereby allowing for spreading infection. The mutations were absent in cells lacking A3C but were induced after transient expression of A3C in the infected target cell. Inhibiting endogenous A3C by RNA interference in Magi cells prevented the viral mutations. Thus, A3C is necessary and sufficient for G-to-A mutations in some HIV-1 strains. A3C-induced mutations occur at levels that allow replication to persist and may therefore contribute to viral diversity. Developing drugs that inhibit A3C may be a novel strategy for delaying viral escape from immune or antiretroviral inhibition.

  3. Target Cell APOBEC3C Can Induce Limited G-to-A Mutation in HIV-1

    Science.gov (United States)

    Bourara, Khaoula; Liegler, Teri J; Grant, Robert M

    2007-01-01

    The evolutionary success of primate lentiviruses reflects their high capacity to mutate and adapt to new host species, immune responses within individual hosts, and, in recent years, antiviral drugs. APOBEC3G (A3G) and APOBEC3F (A3F) are host cell DNA-editing enzymes that induce extensive HIV-1 mutation that severely attenuates viral replication. The HIV-1 virion infectivity factor (Vif), expressed in vivo, counteracts the antiviral activity of A3G and A3F by inducing their degradation. Other APOBECs may contribute more to viral diversity by inducing less extensive mutations allowing viral replication to persist. Here we show that in APOBEC3C (A3C)-expressing cells infected with the patient-derived HIV-1 molecular clones 210WW, 210WM, 210MW, and 210MM, and the lab-adapted molecular clone LAI, viral G-to-A mutations were detected in the presence of Vif expression. Mutations occurred primarily in the GA context and were relatively infrequent, thereby allowing for spreading infection. The mutations were absent in cells lacking A3C but were induced after transient expression of A3C in the infected target cell. Inhibiting endogenous A3C by RNA interference in Magi cells prevented the viral mutations. Thus, A3C is necessary and sufficient for G-to-A mutations in some HIV-1 strains. A3C-induced mutations occur at levels that allow replication to persist and may therefore contribute to viral diversity. Developing drugs that inhibit A3C may be a novel strategy for delaying viral escape from immune or antiretroviral inhibition. PMID:17967058

  4. A multi-scale mathematical modeling framework to investigate anti-viral therapeutic opportunities in targeting HIV-1 accessory proteins.

    Science.gov (United States)

    Suryawanshi, Gajendra W; Hoffmann, Alexander

    2015-12-07

    Human immunodeficiency virus-1 (HIV-1) employs accessory proteins to evade innate immune responses by neutralizing the anti-viral activity of host restriction factors. Apolipoprotein B mRNA-editing enzyme 3G (APOBEC3G, A3G) and bone marrow stromal cell antigen 2 (BST2) are host resistance factors that potentially inhibit HIV-1 infection. BST2 reduces viral production by tethering budding HIV-1 particles to virus producing cells, while A3G inhibits the reverse transcription (RT) process and induces viral genome hypermutation through cytidine deamination, generating fewer replication competent progeny virus. Two HIV-1 proteins counter these cellular restriction factors: Vpu, which reduces surface BST2, and Vif, which degrades cellular A3G. The contest between these host and viral proteins influences whether HIV-1 infection is established and progresses towards AIDS. In this work, we present an age-structured multi-scale viral dynamics model of in vivo HIV-1 infection. We integrated the intracellular dynamics of anti-viral activity of the host factors and their neutralization by HIV-1 accessory proteins into the virus/cell population dynamics model. We calculate the basic reproductive ratio (Ro) as a function of host-viral protein interaction coefficients, and numerically simulated the multi-scale model to understand HIV-1 dynamics following host factor-induced perturbations. We found that reducing the influence of Vpu triggers a drop in Ro, revealing the impact of BST2 on viral infection control. Reducing Vif׳s effect reveals the restrictive efficacy of A3G in blocking RT and in inducing lethal hypermutations, however, neither of these factors alone is sufficient to fully restrict HIV-1 infection. Interestingly, our model further predicts that BST2 and A3G function synergistically, and delineates their relative contribution in limiting HIV-1 infection and disease progression. We provide a robust modeling framework for devising novel combination therapies that target

  5. HIV-1 and hijacking of the host immune system: the current scenario.

    Science.gov (United States)

    Imran, Muhammad; Manzoor, Sobia; Saalim, Muhammad; Resham, Saleha; Ashraf, Javed; Javed, Aneela; Waqar, Ahmed Bilal

    2016-10-01

    Human immunodeficiency virus (HIV) infection is a major health burden across the world which leads to the development of acquired immune deficiency syndrome (AIDS). This review article discusses the prevalence of HIV, its major routes of transmission, natural immunity, and evasion from the host immune system. HIV is mostly prevalent in Sub-Saharan Africa and low income countries. It is mostly transmitted by sharing syringe needles, blood transfusion, and sexual routes. The host immune system is categorized into three main types; the innate, the adaptive, and the intrinsic immune system. Regarding the innate immune system against HIV, the key players are mucosal membrane, dendritic cells (DCs), complement system, interferon, and host Micro RNAs. The major components of the adaptive immune system exploited by HIV are T cells mainly CD4+ T cells and B cells. The intrinsic immune system confronted by HIV involves (apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G) APOBEC3G, tripartite motif 5-α (TRIM5a), terherin, and (SAM-domain HD-domain containing protein) SAMHD1. HIV-1 efficiently interacts with the host immune system, exploits the host machinery, successfully replicates and transmits from one cell to another. Further research is required to explore evasion strategies of HIV to develop novel therapeutic approaches against HIV.

  6. Characterization of RNA binding and chaperoning activities of HIV-1 Vif protein. Importance of the C-terminal unstructured tail.

    Science.gov (United States)

    Sleiman, Dona; Bernacchi, Serena; Xavier Guerrero, Santiago; Brachet, Franck; Larue, Valéry; Paillart, Jean-Christophe; Tisne, Carine

    2014-01-01

    The viral infectivity factor (Vif) is essential for the productive infection and dissemination of HIV-1 in non-permissive cells, containing the cellular anti-HIV defense cytosine deaminases APOBEC3 (A3G and A3F). Vif neutralizes the antiviral activities of the APOBEC3G/F by diverse mechanisms including their degradation through the ubiquitin/proteasome pathway and their translational inhibition. In addition, Vif appears to be an active partner of the late steps of viral replication by interacting with Pr55(Gag), reverse transcriptase and genomic RNA. Here, we expressed and purified full-length and truncated Vif proteins, and analyzed their RNA binding and chaperone properties. First, we showed by CD and NMR spectroscopies that the N-terminal domain of Vif is highly structured in solution, whereas the C-terminal domain remains mainly unfolded. Both domains exhibited substantial RNA binding capacities with dissociation constants in the nanomolar range, whereas the basic unfolded C-terminal domain of Vif was responsible in part for its RNA chaperone activity. Second, we showed by NMR chemical shift mapping that Vif and NCp7 share the same binding sites on tRNA(Lys) 3, the primer of HIV-1 reverse transcriptase. Finally, our results indicate that Vif has potent RNA chaperone activity and provide direct evidence for an important role of the unstructured C-terminal domain of Vif in this capacity.

  7. The importance of becoming double-stranded: Innate immunity and the kinetic model of HIV-1 central plus strand synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Poeschla, Eric, E-mail: poeschla.eric@mayo.edu

    2013-06-20

    Central initiation of plus strand synthesis is a conserved feature of lentiviruses and certain other retroelements. This complication of the standard reverse transcription mechanism produces a transient “central DNA flap” in the viral cDNA, which has been proposed to mediate its subsequent nuclear import. This model has assumed that the important feature is the flapped DNA structure itself rather than the process that produces it. Recently, an alternative kinetic model was proposed. It posits that central plus strand synthesis functions to accelerate conversion to the double-stranded state, thereby helping HIV-1 to evade single-strand DNA-targeting antiviral restrictions such as APOBEC3 proteins, and perhaps to avoid innate immune sensor mechanisms. The model is consistent with evidence that lentiviruses must often synthesize their cDNAs when dNTP concentrations are limiting and with data linking reverse transcription and uncoating. There may be additional kinetic advantages for the artificial genomes of lentiviral gene therapy vectors. - Highlights: • Two main functional models for HIV central plus strand synthesis have been proposed. • In one, a transient central DNA flap in the viral cDNA mediates HIV-1 nuclear import. • In the other, multiple kinetic consequences are emphasized. • One is defense against APOBEC3G, which deaminates single-stranded DNA. • Future questions pertain to antiviral restriction, uncoating and nuclear import.

  8. Long-term passage of Vif-null HIV-1 in CD4(+) T cells expressing sub-lethal levels of APOBEC proteins fails to develop APOBEC resistance.

    Science.gov (United States)

    Miyagi, Eri; Kao, Sandra; Fumitaka, Miyoshi; Buckler-White, Alicia; Plishka, Ron; Strebel, Klaus

    2017-04-01

    APOBEC3G (A3G) is a cytidine deaminase with potent antiviral activity that is antagonized by Vif. A3G is expressed in a cell type-specific manner and some semi-permissive cells, including A3.01, express A3G but fail to block replication of Vif-null HIV-1. Here we explored the semi-permissive nature of A3.01 cells and found it to be defined exclusively by the levels of A3G. Indeed, minor changes in A3G levels rendered A3.01 cells either fully permissive or non-permissive for Vif-null HIV-1. Our data indicate that A3.01 cells express sub-lethal levels of catalytically active A3G that affects Vif-null HIV-1 at the proviral level but does not completely block virus replication due to purifying selection. Attempts to use the selective pressure exerted by such sub-lethal levels of A3G to select for APOBEC-resistant Vif-null virus capable of replicating in H9 cells failed despite passaging virus for five months, demonstrating that Vif is a critical viral accessory protein.

  9. Psychoneuroimmunology and HIV-1.

    Science.gov (United States)

    Antoni, Michael H.; And Others

    1990-01-01

    Presents evidence describing benefits of behavioral interventions such as aerobic exercise training on both psychological and immunological functioning among high risk human immunodeficiency virus-Type 1 (HIV-1) seronegative and very early stage seropositive homosexual men. HIV-1 infection is cast as chronic disease for which early…

  10. Natural polymorphisms in human APOBEC3H and HIV-1 Vif combine in primary T lymphocytes to affect viral G-to-A mutation levels and infectivity.

    Science.gov (United States)

    Refsland, Eric W; Hultquist, Judd F; Luengas, Elizabeth M; Ikeda, Terumasa; Shaban, Nadine M; Law, Emily K; Brown, William L; Reilly, Cavan; Emerman, Michael; Harris, Reuben S

    2014-11-01

    The Vif protein of HIV-1 allows virus replication by degrading several members of the host-encoded APOBEC3 family of DNA cytosine deaminases. Polymorphisms in both host APOBEC3 genes and the viral vif gene have the potential to impact the extent of virus replication among individuals. The most genetically diverse of the seven human APOBEC3 genes is APOBEC3H with seven known haplotypes. Overexpression studies have shown that a subset of these variants express stable and active proteins, whereas the others encode proteins with a short half-life and little, if any, antiviral activity. We demonstrate that these stable/unstable phenotypes are an intrinsic property of endogenous APOBEC3H proteins in primary CD4+ T lymphocytes and confer differential resistance to HIV-1 infection in a manner that depends on natural variation in the Vif protein of the infecting virus. HIV-1 with a Vif protein hypo-functional for APOBEC3H degradation, yet fully able to counteract APOBEC3D, APOBEC3F, and APOBEC3G, was susceptible to restriction and hypermutation in stable APOBEC3H expressing lymphocytes, but not in unstable APOBEC3H expressing lymphocytes. In contrast, HIV-1 with hyper-functional Vif counteracted stable APOBEC3H proteins as well as all other endogenous APOBEC3s and replicated to high levels. We also found that APOBEC3H protein levels are induced over 10-fold by infection. Finally, we found that the global distribution of stable/unstable APOBEC3H haplotypes correlates with the distribution a critical hyper/hypo-functional Vif amino acid residue. These data combine to strongly suggest that stable APOBEC3H haplotypes present as in vivo barriers to HIV-1 replication, that Vif is capable of adapting to these restrictive pressures, and that an evolutionary equilibrium has yet to be reached.

  11. Natural polymorphisms in human APOBEC3H and HIV-1 Vif combine in primary T lymphocytes to affect viral G-to-A mutation levels and infectivity.

    Directory of Open Access Journals (Sweden)

    Eric W Refsland

    2014-11-01

    Full Text Available The Vif protein of HIV-1 allows virus replication by degrading several members of the host-encoded APOBEC3 family of DNA cytosine deaminases. Polymorphisms in both host APOBEC3 genes and the viral vif gene have the potential to impact the extent of virus replication among individuals. The most genetically diverse of the seven human APOBEC3 genes is APOBEC3H with seven known haplotypes. Overexpression studies have shown that a subset of these variants express stable and active proteins, whereas the others encode proteins with a short half-life and little, if any, antiviral activity. We demonstrate that these stable/unstable phenotypes are an intrinsic property of endogenous APOBEC3H proteins in primary CD4+ T lymphocytes and confer differential resistance to HIV-1 infection in a manner that depends on natural variation in the Vif protein of the infecting virus. HIV-1 with a Vif protein hypo-functional for APOBEC3H degradation, yet fully able to counteract APOBEC3D, APOBEC3F, and APOBEC3G, was susceptible to restriction and hypermutation in stable APOBEC3H expressing lymphocytes, but not in unstable APOBEC3H expressing lymphocytes. In contrast, HIV-1 with hyper-functional Vif counteracted stable APOBEC3H proteins as well as all other endogenous APOBEC3s and replicated to high levels. We also found that APOBEC3H protein levels are induced over 10-fold by infection. Finally, we found that the global distribution of stable/unstable APOBEC3H haplotypes correlates with the distribution a critical hyper/hypo-functional Vif amino acid residue. These data combine to strongly suggest that stable APOBEC3H haplotypes present as in vivo barriers to HIV-1 replication, that Vif is capable of adapting to these restrictive pressures, and that an evolutionary equilibrium has yet to be reached.

  12. A single HIV-1 cluster and a skewed immune homeostasis drive the early spread of HIV among resting CD4+ cell subsets within one month post-infection.

    Science.gov (United States)

    Bacchus, Charline; Cheret, Antoine; Avettand-Fenoël, Véronique; Nembot, Georges; Mélard, Adeline; Blanc, Catherine; Lascoux-Combe, Caroline; Slama, Laurence; Allegre, Thierry; Allavena, Clotilde; Yazdanpanah, Yazdan; Duvivier, Claudine; Katlama, Christine; Goujard, Cécile; Seksik, Bao Chau Phung; Leplatois, Anne; Molina, Jean-Michel; Meyer, Laurence; Autran, Brigitte; Rouzioux, Christine

    2013-01-01

    Optimizing therapeutic strategies for an HIV cure requires better understanding the characteristics of early HIV-1 spread among resting CD4+ cells within the first month of primary HIV-1 infection (PHI). We studied the immune distribution, diversity, and inducibility of total HIV-DNA among the following cell subsets: monocytes, peripheral blood activated and resting CD4 T cells, long-lived (naive [TN] and central-memory [TCM]) and short-lived (transitional-memory [TTM] and effector-memory cells [TEM]) resting CD4+T cells from 12 acutely-infected individuals recruited at a median 36 days from infection. Cells were sorted for total HIV-DNA quantification, phylogenetic analysis and inducibility, all studied in relation to activation status and cell signaling. One month post-infection, a single CCR5-restricted viral cluster was massively distributed in all resting CD4+ subsets from 88% subjects, while one subject showed a slight diversity. High levels of total HIV-DNA were measured among TN (median 3.4 log copies/million cells), although 10-fold less (p = 0.0005) than in equally infected TCM (4.5), TTM (4.7) and TEM (4.6) cells. CD3-CD4+ monocytes harbored a low viral burden (median 2.3 log copies/million cells), unlike equally infected resting and activated CD4+ T cells (4.5 log copies/million cells). The skewed repartition of resting CD4 subsets influenced their contribution to the pool of resting infected CD4+T cells, two thirds of which consisted of short-lived TTM and TEM subsets, whereas long-lived TN and TCM subsets contributed the balance. Each resting CD4 subset produced HIV in vitro after stimulation with anti-CD3/anti-CD28+IL-2 with kinetics and magnitude varying according to subset differentiation, while IL-7 preferentially induced virus production from long-lived resting TN cells. In conclusion, within a month of infection, a clonal HIV-1 cluster is massively distributed among resting CD4 T-cell subsets with a flexible inducibility, suggesting that

  13. A single HIV-1 cluster and a skewed immune homeostasis drive the early spread of HIV among resting CD4+ cell subsets within one month post-infection.

    Directory of Open Access Journals (Sweden)

    Charline Bacchus

    Full Text Available Optimizing therapeutic strategies for an HIV cure requires better understanding the characteristics of early HIV-1 spread among resting CD4+ cells within the first month of primary HIV-1 infection (PHI. We studied the immune distribution, diversity, and inducibility of total HIV-DNA among the following cell subsets: monocytes, peripheral blood activated and resting CD4 T cells, long-lived (naive [TN] and central-memory [TCM] and short-lived (transitional-memory [TTM] and effector-memory cells [TEM] resting CD4+T cells from 12 acutely-infected individuals recruited at a median 36 days from infection. Cells were sorted for total HIV-DNA quantification, phylogenetic analysis and inducibility, all studied in relation to activation status and cell signaling. One month post-infection, a single CCR5-restricted viral cluster was massively distributed in all resting CD4+ subsets from 88% subjects, while one subject showed a slight diversity. High levels of total HIV-DNA were measured among TN (median 3.4 log copies/million cells, although 10-fold less (p = 0.0005 than in equally infected TCM (4.5, TTM (4.7 and TEM (4.6 cells. CD3-CD4+ monocytes harbored a low viral burden (median 2.3 log copies/million cells, unlike equally infected resting and activated CD4+ T cells (4.5 log copies/million cells. The skewed repartition of resting CD4 subsets influenced their contribution to the pool of resting infected CD4+T cells, two thirds of which consisted of short-lived TTM and TEM subsets, whereas long-lived TN and TCM subsets contributed the balance. Each resting CD4 subset produced HIV in vitro after stimulation with anti-CD3/anti-CD28+IL-2 with kinetics and magnitude varying according to subset differentiation, while IL-7 preferentially induced virus production from long-lived resting TN cells. In conclusion, within a month of infection, a clonal HIV-1 cluster is massively distributed among resting CD4 T-cell subsets with a flexible inducibility

  14. Distinct determinants in HIV-1 Vif and human APOBEC3 proteins are required for the suppression of diverse host anti-viral proteins.

    Directory of Open Access Journals (Sweden)

    Wenyan Zhang

    Full Text Available BACKGROUND: APOBEC3G (A3G and related cytidine deaminases of the APOBEC3 family of proteins are potent inhibitors of many retroviruses, including HIV-1. Formation of infectious HIV-1 requires the suppression of multiple cytidine deaminases by Vif. HIV-1 Vif suppresses various APOBEC3 proteins through the common mechanism of recruiting the Cullin5-ElonginB-ElonginC E3 ubiquitin ligase to induce target protein polyubiquitination and proteasome-mediated degradation. The domains in Vif and various APOBEC3 proteins required for APOBEC3 recognition and degradation have not been fully characterized. METHODS AND FINDINGS: In the present study, we have demonstrated that the regions of APOBEC3F (A3F that are required for its HIV-1-mediated binding and degradation are distinct from those reported for A3G. We found that the C-terminal cytidine deaminase domain (C-CDD of A3F alone is sufficient for its interaction with HIV-1 Vif and its Vif-mediated degradation. We also observed that the domains of HIV-1 Vif that are uniquely required for its functional interaction with full-length A3F are also required for the degradation of the C-CDD of A3F; in contrast, those Vif domains that are uniquely required for functional interaction with A3G are not required for the degradation of the C-CDD of A3F. Interestingly, the HIV-1 Vif domains required for the degradation of A3F are also required for the degradation of A3C and A3DE. On the other hand, the Vif domains uniquely required for the degradation of A3G are dispensable for the degradation of cytidine deaminases A3C and A3DE. CONCLUSIONS: Our data suggest that distinct regions of A3F and A3G are targeted by HIV-1 Vif molecules. However, HIV-1 Vif suppresses A3F, A3C, and A3DE through similar recognition determinants, which are conserved among Vif molecules from diverse HIV-1 strains. Mapping these determinants may be useful for the design of novel anti-HIV inhibitors.

  15. An intronic G run within HIV-1 intron 2 is critical for splicing regulation of vif mRNA.

    Science.gov (United States)

    Widera, Marek; Erkelenz, Steffen; Hillebrand, Frank; Krikoni, Aikaterini; Widera, Darius; Kaisers, Wolfgang; Deenen, René; Gombert, Michael; Dellen, Rafael; Pfeiffer, Tanya; Kaltschmidt, Barbara; Münk, Carsten; Bosch, Valerie; Köhrer, Karl; Schaal, Heiner

    2013-03-01

    Within target T lymphocytes, human immunodeficiency virus type I (HIV-1) encounters the retroviral restriction factor APOBEC3G (apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G; A3G), which is counteracted by the HIV-1 accessory protein Vif. Vif is encoded by intron-containing viral RNAs that are generated by splicing at 3' splice site (3'ss) A1 but lack splicing at 5'ss D2, which results in the retention of a large downstream intron. Hence, the extents of activation of 3'ss A1 and repression of D2, respectively, determine the levels of vif mRNA and thus the ability to evade A3G-mediated antiviral effects. The use of 3'ss A1 can be enhanced or repressed by splicing regulatory elements that control the recognition of downstream 5'ss D2. Here we show that an intronic G run (G(I2)-1) represses the use of a second 5'ss, termed D2b, that is embedded within intron 2 and, as determined by RNA deep-sequencing analysis, is normally inefficiently used. Mutations of G(I2)-1 and activation of D2b led to the generation of transcripts coding for Gp41 and Rev protein isoforms but primarily led to considerable upregulation of vif mRNA expression. We further demonstrate, however, that higher levels of Vif protein are actually detrimental to viral replication in A3G-expressing T cell lines but not in A3G-deficient cells. These observations suggest that an appropriate ratio of Vif-to-A3G protein levels is required for optimal virus replication and that part of Vif level regulation is effected by the novel G run identified here.

  16. HIV-1 Vif蛋白的体内表达及其生物学功能%In Vivo Expression and Biological Function of HIV-1 Vif Protein

    Institute of Scientific and Technical Information of China (English)

    张文艳; 孔维; 于湘晖

    2008-01-01

    目的 分别构建带有6His和mbp tag的HIV-1 Vif基因真核表达载体,在体内表达融合蛋白,并检测其生物学功能.方法 PCR扩增带有6His和mbp tag的HIV-1 Vif基因,克隆至真核表达载体VRl012上.将抗病毒因子APOBEC3G(A3G)分别与空载体VR1012、HIV-1野生型Vif/VR1012、Vif-mbp/VR1012和Vif-6His/VR1012共同转染293T细胞,检测Vif-mbp和Vif-6His的表达,并进行A3G体内降解试验.将A3G和/或可产生病毒的质粒HXB2Neo △ Aif分别与HIV-1野生型Vif/VR1012、Vif-mbp/VR1012和Vif-6His/VR1012共同转染293T细胞,通过A3G包装进病毒和Magi细胞感染试验,进一步检测HIV-1 Vif-mbp和Vif-6His融合蛋白的生物学功能.结果 重组表达质粒Vif-mbp/VR1012和Vif-6His/VR1012经双酶切鉴定证明构建正确.转染293T细胞48 h后,Vif-mbp和Vif-6His融合蛋白均有表达,但表达的Vff-mbp有不同程度的降解.Vif-6His可降解A3G,使其表达量下降至10%左右,而Vif-mbp几乎不能降解A3G.Vif-6His可阻止A3G包装进病毒颗粒中,而Vif-mbp无此功能.Vif-mbp可使HXB2Neo △ Vif病毒感染能力恢复至15%,而Vif-6His可使其恢复至86%.结论 已成功构建了带有6His和mbp tag的HIV-1 Vif基因真核表达载体,表达的Vif-mbp融合蛋白影响了Vif的生物学功能,但Vif-6His融合蛋白不影响Vif的生物学功能.

  17. Core-binding factor β increases the affinity between human Cullin 5 and HIV-1 Vif within an E3 ligase complex.

    Science.gov (United States)

    Salter, Jason D; Lippa, Geoffrey M; Belashov, Ivan A; Wedekind, Joseph E

    2012-11-06

    HIV-1 Vif masquerades as a receptor for a cellular E3 ligase harboring Elongin B, Elongin C, and Cullin 5 (EloB/C/Cul5) proteins that facilitate degradation of the antiretroviral factor APOBEC3G (A3G). This Vif-mediated activity requires human core-binding factor β (CBFβ) in contrast to cellular substrate receptors. We observed calorimetrically that Cul5 binds tighter to full-length Vif((1-192))/EloB/C/CBFβ (K(d) = 5 ± 2 nM) than to Vif((95-192))/EloB/C (K(d) = 327 ± 40 nM), which cannot bind CBFβ. A comparison of heat capacity changes supports a model in which CBFβ prestabilizes Vif((1-192)) relative to Vif((95-192)), consistent with a stronger interaction of Cul5 with Vif's C-terminal Zn(2+)-binding motif. An additional interface between Cul5 and an N-terminal region of Vif appears to be plausible, which has therapeutic design implications.

  18. HIV—1病毒感染因子Vif及其相关抑制剂的研究进展%Progress in the study of HIV-1 Vif and related inhibitors

    Institute of Scientific and Technical Information of China (English)

    李震宇; 展鹏; 刘新泳

    2010-01-01

    HIV-1(human immunodeficiency virus type 1)病毒感染因子Vif(viral infectivity factor)是高度保守的碱性磷酸化蛋白质,是HIV-1的辅助调节蛋白之一.Vif蛋白的主要功能是能够介导宿主细胞体内载脂蛋白BmRNA编辑酶催化多肽样蛋白3G (apolipoprotein B mRNA editing enzyme catalytic polypeptide like 3G,APOBEC3G)的降解,从而增强病毒的感染性.此外,它还具有调节病毒的逆转录和复制晚期以及诱导细胞G2期停滞等功能.目前,许多实验室已经针对Vif蛋白进行抑制剂的设计.本文简要叙述了Vif蛋白的结构与功能,并主要对其抑制剂的最新进展进行了综述.

  19. HSV-1/HSV-2 Infection-Related Cancers in Bantu Populations Driving HIV-1 Prevalence in Africa: Tracking the Origin of AIDS at the Onset of the 20th Century

    Directory of Open Access Journals (Sweden)

    Jacqueline Le Goaster

    2016-11-01

    Full Text Available Introduction: At the onset of the 20th century, ancient clinical observations of cancer epidemics in Bantu populations of Sub-Saharan Africa were discovered. They were reported from 1914 to 1960, but remained unexplained. In 1983, in San Francisco, Calif., USA, cancer epidemics were related to infections by the human immunodeficiency virus type 1 (HIV-1 known as AIDS disease. Yet since 1996, it is known that HIV-1 strains are not the only ones involved. In Sub-Saharan Africa, recurrent orobuccal herpes simplex virus type 1 (HSV-1 and genital recurrent herpes simplex virus type 2 (HSV-2 appeared many times prior to infection by HIV-1. Case Reports: Data on these ancient medical observations regarding African cancer epidemics can today be referred to as the relationship between the unfortunate immune deficiency of herpes in Bantu populations and HIV-1 viral strains. For centuries, the Bantu populations dispersed in forests were living in close proximity to chimpanzees infected by simian immunodeficiency virus (SIV and were exposed to SIV contamination which became HIV-1 in human beings. Presently, these unexplained Bantu cancer epidemics can be linked to the viral partnership of HSV-1/HSV-2 to HIV-1 strains. Conclusion: The key issue is now to prevent HSV-1/HSV-2 diseases related to HIV-1. An anti-herpes treatment administered early during childhood to Bantu populations will offer a mean of preventing herpes diseases related to HIV-1 infection and hence avoid cancer epidemics.

  20. High Expression of Antiviral and Vitamin D Pathway Genes Are a Natural Characteristic of a Small Cohort of HIV-1-Exposed Seronegative Individuals

    Science.gov (United States)

    Aguilar-Jimenez, Wbeimar; Saulle, Irma; Trabattoni, Daria; Vichi, Francesca; Lo Caputo, Sergio; Mazzotta, Francesco; Rugeles, Maria T.; Clerici, Mario; Biasin, Mara

    2017-01-01

    Natural resistance to HIV-1 infection is influenced by genetics, viral-exposure, and endogenous immunomodulators such as vitamin D (VitD), being a multifactorial phenomenon that characterizes HIV-1-exposed seronegative individuals (HESNs). We compared mRNA expression of 10 antivirals, 5 immunoregulators, and 3 VitD pathway genes by qRT-PCR in cells of a small cohort of 11 HESNs, 16 healthy-controls (HCs), and 11 seropositives (SPs) at baseline, in response to calcidiol (VitD precursor) and/or aldithriol-2-(AT2)-inactivated HIV-1. In addition, the expression of TIM-3 on T and NK cells of six HCs after calcidiol and calcitriol (active VitD) treatments was evaluated by flow cytometry. Calcidiol increased the mRNA expression of HAVCR2 (TIM-3; Th1-cells inhibitor) in HCs and HESNs. AT2-HIV-1 increased the mRNA expression of the activating VitD enzyme CYP27B1, of the endogenous antiviral proteins MX2, TRIM22, APOBEC3G, and of immunoregulators ERAP2 and HAVCR2, but reduced the mRNA expression of VitD receptor (VDR) and antiviral peptides PI3 and CAMP in all groups. Remarkably, higher mRNA levels of VDR, CYP27B1, PI3, CAMP, SLPI, and of ERAP2 were found in HESNs compared to HCs either at baseline or after stimuli. Furthermore, calcitriol increases the percentage of CD4+ T cells expressing TIM-3 protein compared to EtOH controls. These results suggest that high mRNA expression of antiviral and VitD pathway genes could be genetically determined in HESNs more than viral-induced at least in peripheral blood mononuclear cells. Moreover, the virus could potentiate bio-activation and use of VitD, maintaining the homeostasis of the immune system. Interestingly, VitD-induced TIM-3 on T cells, a T cell inhibitory and anti-HIV-1 molecule, requires further studies to analyze the functional outcomes during HIV-1 infection. PMID:28243241

  1. The SOCS-box of HIV-1 Vif interacts with ElonginBC by induced-folding to recruit its Cul5-containing ubiquitin ligase complex.

    Directory of Open Access Journals (Sweden)

    Julien R C Bergeron

    Full Text Available The HIV-1 viral infectivity factor (Vif protein recruits an E3 ubiquitin ligase complex, comprising the cellular proteins elongin B and C (EloBC, cullin 5 (Cul5 and RING-box 2 (Rbx2, to the anti-viral proteins APOBEC3G (A3G and APOBEC3F (A3F and induces their polyubiquitination and proteasomal degradation. In this study, we used purified proteins and direct in vitro binding assays, isothermal titration calorimetry and NMR spectroscopy to describe the molecular mechanism for assembly of the Vif-EloBC ternary complex. We demonstrate that Vif binds to EloBC in two locations, and that both interactions induce structural changes in the SOCS box of Vif as well as EloBC. In particular, in addition to the previously established binding of Vif's BC box to EloC, we report a novel interaction between the conserved Pro-Pro-Leu-Pro motif of Vif and the C-terminal domain of EloB. Using cell-based assays, we further show that this interaction is necessary for the formation of a functional ligase complex, thus establishing a role of this motif. We conclude that HIV-1 Vif engages EloBC via an induced-folding mechanism that does not require additional co-factors, and speculate that these features distinguish Vif from other EloBC specificity factors such as cellular SOCS proteins, and may enhance the prospects of obtaining therapeutic inhibitors of Vif function.

  2. Hyperthermia stimulates HIV-1 replication.

    Directory of Open Access Journals (Sweden)

    Ferdinand Roesch

    Full Text Available HIV-infected individuals may experience fever episodes. Fever is an elevation of the body temperature accompanied by inflammation. It is usually beneficial for the host through enhancement of immunological defenses. In cultures, transient non-physiological heat shock (42-45°C and Heat Shock Proteins (HSPs modulate HIV-1 replication, through poorly defined mechanisms. The effect of physiological hyperthermia (38-40°C on HIV-1 infection has not been extensively investigated. Here, we show that culturing primary CD4+ T lymphocytes and cell lines at a fever-like temperature (39.5°C increased the efficiency of HIV-1 replication by 2 to 7 fold. Hyperthermia did not facilitate viral entry nor reverse transcription, but increased Tat transactivation of the LTR viral promoter. Hyperthermia also boosted HIV-1 reactivation in a model of latently-infected cells. By imaging HIV-1 transcription, we further show that Hsp90 co-localized with actively transcribing provirus, and this phenomenon was enhanced at 39.5°C. The Hsp90 inhibitor 17-AAG abrogated the increase of HIV-1 replication in hyperthermic cells. Altogether, our results indicate that fever may directly stimulate HIV-1 replication, in a process involving Hsp90 and facilitation of Tat-mediated LTR activity.

  3. HIV-1 subtypes in Yugoslavia.

    Science.gov (United States)

    Stanojevic, Maja; Papa, Anna; Papadimitriou, Evagelia; Zerjav, Sonja; Jevtovic, Djordje; Salemovic, Dubravka; Jovanovic, Tanja; Antoniadis, Antonis

    2002-05-01

    To gain insight concerning the genetic diversity of HIV-1 viruses associated with the HIV-1 epidemic in Yugoslavia, 45 specimens from HIV-1-infected individuals were classified into subtypes by sequence-based phylogenetic analysis of the polymerase (pol) region of the viral genome. Forty-one of 45 specimens (91.2%) were identified as pol subtype B, 2 of 45 as subtype C (4.4%), 1 of 45 as CRF01_AE (2.2%), and 1 as CRF02_AG recombinant (2.2%). Nucleotide divergence among subtype B sequences was 4.8%. Results of this study show that among HIV-1-infected patients in Yugoslavia subtype B predominates (91.5%), whereas non-B subtypes are present at a low percentage, mostly related to travel abroad.

  4. Identifying HIV-1 dual infections

    Directory of Open Access Journals (Sweden)

    Cornelissen Marion

    2007-09-01

    Full Text Available Abstract Transmission of human immunodeficiency virus (HIV is no exception to the phenomenon that a second, productive infection with another strain of the same virus is feasible. Experiments with RNA viruses have suggested that both coinfections (simultaneous infection with two strains of a virus and superinfections (second infection after a specific immune response to the first infecting strain has developed can result in increased fitness of the viral population. Concerns about dual infections with HIV are increasing. First, the frequent detection of superinfections seems to indicate that it will be difficult to develop a prophylactic vaccine. Second, HIV-1 superinfections have been associated with accelerated disease progression, although this is not true for all persons. In fact, superinfections have even been detected in persons controlling their HIV infections without antiretroviral therapy. Third, dual infections can give rise to recombinant viruses, which are increasingly found in the HIV-1 epidemic. Recombinants could have increased fitness over the parental strains, as in vitro models suggest, and could exhibit increased pathogenicity. Multiple drug resistant (MDR strains could recombine to produce a pan-resistant, transmittable virus. We will describe in this review what is presently known about super- and re-infection among ambient viral infections, as well as the first cases of HIV-1 superinfection, including HIV-1 triple infections. The clinical implications, the impact of the immune system, and the effect of anti-retroviral therapy will be covered, as will as the timing of HIV superinfection. The methods used to detect HIV-1 dual infections will be discussed in detail. To increase the likelihood of detecting a dual HIV-1 infection, pre-selection of patients can be done by serotyping, heteroduplex mobility assays (HMA, counting the degenerate base codes in the HIV-1 genotyping sequence, or surveying unexpected increases in the

  5. HIV-1 assembly in macrophages

    Directory of Open Access Journals (Sweden)

    Benaroch Philippe

    2010-04-01

    Full Text Available Abstract The molecular mechanisms involved in the assembly of newly synthesized Human Immunodeficiency Virus (HIV particles are poorly understood. Most of the work on HIV-1 assembly has been performed in T cells in which viral particle budding and assembly take place at the plasma membrane. In contrast, few studies have been performed on macrophages, the other major target of HIV-1. Infected macrophages represent a viral reservoir and probably play a key role in HIV-1 physiopathology. Indeed macrophages retain infectious particles for long periods of time, keeping them protected from anti-viral immune response or drug treatments. Here, we present an overview of what is known about HIV-1 assembly in macrophages as compared to T lymphocytes or cell lines. Early electron microscopy studies suggested that viral assembly takes place at the limiting membrane of an intracellular compartment in macrophages and not at the plasma membrane as in T cells. This was first considered as a late endosomal compartment in which viral budding seems to be similar to the process of vesicle release into multi-vesicular bodies. This view was notably supported by a large body of evidence involving the ESCRT (Endosomal Sorting Complex Required for Transport machinery in HIV-1 budding, the observation of viral budding profiles in such compartments by immuno-electron microscopy, and the presence of late endosomal markers associated with macrophage-derived virions. However, this model needs to be revisited as recent data indicate that the viral compartment has a neutral pH and can be connected to the plasma membrane via very thin micro-channels. To date, the exact nature and biogenesis of the HIV assembly compartment in macrophages remains elusive. Many cellular proteins potentially involved in the late phases of HIV-1 cycle have been identified; and, recently, the list has grown rapidly with the publication of four independent genome-wide screens. However, their respective

  6. Structural insights for HIV-1 therapeutic strategies targeting Vif.

    Science.gov (United States)

    Salter, Jason D; Morales, Guillermo A; Smith, Harold C

    2014-09-01

    HIV-1 viral infectivity factor (Vif) is a viral accessory protein that is required for HIV-1 infection due largely to its role in recruiting antiretroviral factors of the APOBEC3 (apolipoprotein B editing catalytic subunit-like 3) family to an E3 ubiquitin ligase complex for polyubiquitylation and proteasomal degradation. The crystal structure of the (near) full-length Vif protein in complex with Elongin (Elo)B/C, core-binding factor (CBF)β and Cullin (Cul)5 revealed that Vif has a novel structural fold. In our opinion the structural data revealed not only the protein-protein interaction sites that determine Vif stability and interaction with cellular proteins, but also motifs driving Vif homodimerization, which are essential in Vif functionality and HIV-1 infection. Vif-mediated protein-protein interactions are excellent targets for a new class of antiretroviral therapeutics to combat AIDS.

  7. Stochastic simulations suggest that HIV-1 survives close to its error threshold.

    Directory of Open Access Journals (Sweden)

    Kushal Tripathi

    Full Text Available The use of mutagenic drugs to drive HIV-1 past its error threshold presents a novel intervention strategy, as suggested by the quasispecies theory, that may be less susceptible to failure via viral mutation-induced emergence of drug resistance than current strategies. The error threshold of HIV-1, μ c, however, is not known. Application of the quasispecies theory to determine μ c poses significant challenges: Whereas the quasispecies theory considers the asexual reproduction of an infinitely large population of haploid individuals, HIV-1 is diploid, undergoes recombination, and is estimated to have a small effective population size in vivo. We performed population genetics-based stochastic simulations of the within-host evolution of HIV-1 and estimated the structure of the HIV-1 quasispecies and μ c. We found that with small mutation rates, the quasispecies was dominated by genomes with few mutations. Upon increasing the mutation rate, a sharp error catastrophe occurred where the quasispecies became delocalized in sequence space. Using parameter values that quantitatively captured data of viral diversification in HIV-1 patients, we estimated μ c to be 7 x 10(-5-1 x 10(-4 substitutions/site/replication, ≈ 2-6 fold higher than the natural mutation rate of HIV-1, suggesting that HIV-1 survives close to its error threshold and may be readily susceptible to mutagenic drugs. The latter estimate was weakly dependent on the within-host effective population size of HIV-1. With large population sizes and in the absence of recombination, our simulations converged to the quasispecies theory, bridging the gap between quasispecies theory and population genetics-based approaches to describing HIV-1 evolution. Further, μ c increased with the recombination rate, rendering HIV-1 less susceptible to error catastrophe, thus elucidating an added benefit of recombination to HIV-1. Our estimate of μ c may serve as a quantitative guideline for the use of

  8. A Case of Seronegative HIV-1 Infection

    OpenAIRE

    Spivak, Adam M; Brennan, Tim; O'Connell, Karen; Sydnor, Emily; Thomas M Williams; Robert F. Siliciano; Gallant, Joel E.; Blankson, Joel N.

    2010-01-01

    Patients infected with HIV-1 typically seroconvert within weeks of primary infection. In rare cases, patients do not develop antibodies against HIV-1 despite demonstrable infection. We describe an HLA-B*5802 positive individual who presented with AIDS despite repeatedly negative HIV-1 antibody screening tests. Phylogenetic analysis of env clones revealed little sequence diversity, and weak HIV-1 specific CD8+ T cell responses were present to Gag epitopes. The patient seroconverted after immun...

  9. Curcumin derivatives as HIV-1 protease inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Sui, Z.; Li, J.; Craik, C.S.; Ortiz de Montellano, P.R. [Univ. of California, San Francisco, CA (United States)

    1993-12-31

    Curcumin, a non-toxic natural compound from Curcuma longa, has been found to be an HIV-1 protease inhibitor. Some of its derivatives were synthesized and their inhibitory activity against the HIV-1 protease was tested. Curcumin analogues containing boron enhanced the inhibitory activity. At least of the the synthesized compounds irreversibly inhibits the HIV-1 protease.

  10. Diagnostik af HIV-1 infektionen

    DEFF Research Database (Denmark)

    Christiansen, C B; Dickmeiss, E; Bygbjerg, Ib Christian

    1991-01-01

    Different methods have been developed for the diagnosis of HIV infection, i.e. detection of antibodies, antigen and proviral DNA. ELISA methods for detecting HIV-1 antibodies are widely used as screening assays. A sample which is repeatedly positive with ELISA is re-tested with a confirmatory test....... For research purposes, detection of small amounts of proviral DNA can be made with polymerase chain reaction (PCR). The method is not yet applicable in routine diagnosis of HIV infection......., e.g. western blot. Antibodies to HIV-1 are not detectable until 2-3 months after infection, but antigens may be detectable during the last weeks of this initial period, though they disappear with the appearance of the antibodies. In the later stages of HIV infection, HIV antigen is again detectable...

  11. Clinical significance of HIV-1 coreceptor usage

    Directory of Open Access Journals (Sweden)

    Lusso Paolo

    2010-01-01

    Full Text Available Abstract The identification of phenotypically distinct HIV-1 variants with different prevalence during the progression of the disease has been one of the earliest discoveries in HIV-1 biology, but its relevance to AIDS pathogenesis remains only partially understood. The physiological basis for the phenotypic variability of HIV-1 was elucidated with the discovery of distinct coreceptors employed by the virus to infect susceptible cells. The role of the viral phenotype in the variable clinical course and treatment outcome of HIV-1 infection has been extensively investigated over the past two decades. In this review, we summarize the major findings on the clinical significance of the HIV-1 coreceptor usage.

  12. Regional differences in prevalence of HIV-1 discordance in Africa and enrollment of HIV-1 discordant couples into an HIV-1 prevention trial.

    Directory of Open Access Journals (Sweden)

    Jairam R Lingappa

    Full Text Available BACKGROUND: Most HIV-1 transmission in Africa occurs among HIV-1-discordant couples (one partner HIV-1 infected and one uninfected who are unaware of their discordant HIV-1 serostatus. Given the high HIV-1 incidence among HIV-1 discordant couples and to assess efficacy of interventions for reducing HIV-1 transmission, HIV-1 discordant couples represent a critical target population for HIV-1 prevention interventions and prevention trials. Substantial regional differences exist in HIV-1 prevalence in Africa, but regional differences in HIV-1 discordance among African couples, has not previously been reported. METHODOLOGY/PRINCIPAL FINDINGS: The Partners in Prevention HSV-2/HIV-1 Transmission Trial ("Partners HSV-2 Study", the first large HIV-1 prevention trial in Africa involving HIV-1 discordant couples, completed enrollment in May 2007. Partners HSV-2 Study recruitment data from 12 sites from East and Southern Africa were used to assess HIV-1 discordance among couples accessing couples HIV-1 counseling and testing, and to correlate with enrollment of HIV-1 discordant couples. HIV-1 discordance at Partners HSV-2 Study sites ranged from 8-31% of couples tested from the community. Across all study sites and, among all couples with one HIV-1 infected partner, almost half (49% of couples were HIV-1 discordant. Site-specific monthly enrollment of HIV-1 discordant couples into the clinical trial was not directly associated with prevalence of HIV-1 discordance, but was modestly correlated with national HIV-1 counseling and testing rates and access to palliative care/basic health care (r = 0.74, p = 0.09. CONCLUSIONS/SIGNIFICANCE: HIV-1 discordant couples are a critical target for HIV-1 prevention in Africa. In addition to community prevalence of HIV-1 discordance, national infrastructure for HIV-1 testing and healthcare delivery and effective community outreach strategies impact recruitment of HIV-1 discordant couples into HIV-1 prevention trials.

  13. Estimating the impact of plasma HIV-1 RNA reductions on heterosexual HIV-1 transmission risk.

    Directory of Open Access Journals (Sweden)

    Jairam R Lingappa

    Full Text Available BACKGROUND: The risk of sexual transmission of HIV-1 is strongly associated with the level of HIV-1 RNA in plasma making reduction in HIV-1 plasma levels an important target for HIV-1 prevention interventions. A quantitative understanding of the relationship of plasma HIV-1 RNA and HIV-1 transmission risk could help predict the impact of candidate HIV-1 prevention interventions that operate by reducing plasma HIV-1 levels, such as antiretroviral therapy (ART, therapeutic vaccines, and other non-ART interventions. METHODOLOGY/PRINCIPAL FINDINGS: We use prospective data collected from 2004 to 2008 in East and Southern African HIV-1 serodiscordant couples to model the relationship of plasma HIV-1 RNA levels and heterosexual transmission risk with confirmation of HIV-1 transmission events by HIV-1 sequencing. The model is based on follow-up of 3381 HIV-1 serodiscordant couples over 5017 person-years encompassing 108 genetically-linked HIV-1 transmission events. HIV-1 transmission risk was 2.27 per 100 person-years with a log-linear relationship to log(10 plasma HIV-1 RNA. The model predicts that a decrease in average plasma HIV-1 RNA of 0.74 log(10 copies/mL (95% CI 0.60 to 0.97 reduces heterosexual transmission risk by 50%, regardless of the average starting plasma HIV-1 level in the population and independent of other HIV-1-related population characteristics. In a simulated population with a similar plasma HIV-1 RNA distribution the model estimates that 90% of overall HIV-1 infections averted by a 0.74 copies/mL reduction in plasma HIV-1 RNA could be achieved by targeting this reduction to the 58% of the cohort with plasma HIV-1 levels ≥4 log(10 copies/mL. CONCLUSIONS/SIGNIFICANCE: This log-linear model of plasma HIV-1 levels and risk of sexual HIV-1 transmission may help estimate the impact on HIV-1 transmission and infections averted from candidate interventions that reduce plasma HIV-1 RNA levels.

  14. HIV-1 induces DCIR expression in CD4+ T cells.

    Directory of Open Access Journals (Sweden)

    Alexandra A Lambert

    Full Text Available The C-type lectin receptor DCIR, which has been shown very recently to act as an attachment factor for HIV-1 in dendritic cells, is expressed predominantly on antigen-presenting cells. However, this concept was recently challenged by the discovery that DCIR can also be detected in CD4(+ T cells found in the synovial tissue from rheumatoid arthritis (RA patients. Given that RA and HIV-1 infections share common features such as a chronic inflammatory condition and polyclonal immune hyperactivation status, we hypothesized that HIV-1 could promote DCIR expression in CD4(+ T cells. We report here that HIV-1 drives DCIR expression in human primary CD4(+ T cells isolated from patients (from both aviremic/treated and viremic/treatment naive persons and cells acutely infected in vitro (seen in both virus-infected and uninfected cells. Soluble factors produced by virus-infected cells are responsible for the noticed DCIR up-regulation on uninfected cells. Infection studies with Vpr- or Nef-deleted viruses revealed that these two viral genes are not contributing to the mechanism of DCIR induction that is seen following acute infection of CD4(+ T cells with HIV-1. Moreover, we report that DCIR is linked to caspase-dependent (induced by a mitochondria-mediated generation of free radicals and -independent intrinsic apoptotic pathways (involving the death effector AIF. Finally, we demonstrate that the higher surface expression of DCIR in CD4(+ T cells is accompanied by an enhancement of virus attachment/entry, replication and transfer. This study shows for the first time that HIV-1 induces DCIR membrane expression in CD4(+ T cells, a process that might promote virus dissemination throughout the infected organism.

  15. HIV-1 Latency in Monocytes/Macrophages

    Directory of Open Access Journals (Sweden)

    Amit Kumar

    2014-04-01

    Full Text Available Human immunodeficiency virus type 1 (HIV-1 targets CD4+ T cells and cells of the monocyte/macrophage lineage. HIV pathogenesis is characterized by the depletion of T lymphocytes and by the presence of a population of cells in which latency has been established called the HIV-1 reservoir. Highly active antiretroviral therapy (HAART has significantly improved the life of HIV-1 infected patients. However, complete eradication of HIV-1 from infected individuals is not possible without targeting latent sources of infection. HIV-1 establishes latent infection in resting CD4+ T cells and findings indicate that latency can also be established in the cells of monocyte/macrophage lineage. Monocyte/macrophage lineage includes among others, monocytes, macrophages and brain resident macrophages. These cells are relatively more resistant to apoptosis induced by HIV-1, thus are important stable hideouts of the virus. Much effort has been made in the direction of eliminating HIV-1 resting CD4+ T-cell reservoirs. However, it is impossible to achieve a cure for HIV-1 without considering these neglected latent reservoirs, the cells of monocyte/macrophage lineage. In this review we will describe our current understanding of the mechanism of latency in monocyte/macrophage lineage and how such cells can be specifically eliminated from the infected host.

  16. Male reproduction and HIV-1 infection

    NARCIS (Netherlands)

    E. van Leeuwen

    2009-01-01

    From its initial presentation in the early nineteen eighties until 1996, HIV-1 infection almost inevitably led to AIDS, which was a death sentence. Because of the short life expectancy, patients were advised against pregnancy. The improved prognosis of patients with HIV-1 infection following the int

  17. IL-15 promotes activation and expansion of CD8+ T cells in HIV-1 infection

    Science.gov (United States)

    Younes, Souheil-Antoine; Freeman, Michael L.; Mudd, Joseph C.; Shive, Carey L.; Reynaldi, Arnold; Estes, Jacob D.; Deleage, Claire; Lucero, Carissa; Anderson, Jodi; Schacker, Timothy W.; Davenport, Miles P.; McCune, Joseph M.; Hunt, Peter W.; Lee, Sulggi A.; Debernardo, Robert L.; Jacobson, Jeffrey M.; Canaday, David H.; Sekaly, Rafick-Pierre; Sieg, Scott F.; Lederman, Michael M.

    2016-01-01

    In HIV-1–infected patients, increased numbers of circulating CD8+ T cells are linked to increased risk of morbidity and mortality. Here, we identified a bystander mechanism that promotes CD8 T cell activation and expansion in untreated HIV-1–infected patients. Compared with healthy controls, untreated HIV-1–infected patients have an increased population of proliferating, granzyme B+, CD8+ T cells in circulation. Vβ expression and deep sequencing of CDR3 revealed that in untreated HIV-1 infection, cycling memory CD8 T cells possess a broad T cell repertoire that reflects the repertoire of the resting population. This suggests that cycling is driven by bystander activation, rather than specific antigen exposure. Treatment of peripheral blood mononuclear cells with IL-15 induced a cycling, granzyme B+ phenotype in CD8+ T cells. Moreover, elevated IL-15 expression in the lymph nodes of untreated HIV-1–infected patients correlated with circulating CD8+ T cell counts and was normalized in these patients following antiretroviral therapy. Together, these results suggest that IL-15 drives bystander activation of CD8+ T cells, which predicts disease progression in untreated HIV-1–infected patients and suggests that elevated IL-15 may also drive CD8+ T cell expansion that is linked to increased morbidity and mortality in treated patients. PMID:27322062

  18. Cytoplasmic Dynein Promotes HIV-1 Uncoating

    Directory of Open Access Journals (Sweden)

    Paulina Pawlica

    2014-11-01

    Full Text Available Retroviral capsid (CA cores undergo uncoating during their retrograde transport (toward the nucleus, and/or after reaching the nuclear membrane. However, whether HIV-1 CA core uncoating is dependent upon its transport is not understood. There is some evidence that HIV-1 cores retrograde transport involves cytoplasmic dynein complexes translocating on microtubules. Here we investigate the role of dynein-dependent transport in HIV-1 uncoating. To interfere with dynein function, we depleted dynein heavy chain (DHC using RNA interference, and we over-expressed p50/dynamitin. In immunofluorescence microscopy experiments, DHC depletion caused an accumulation of CA foci in HIV-1 infected cells. Using a biochemical assay to monitor HIV-1 CA core disassembly in infected cells, we observed an increase in amounts of intact (pelletable CA cores upon DHC depletion or p50 over-expression. Results from these two complementary assays suggest that inhibiting dynein-mediated transport interferes with HIV-1 uncoating in infected cells, indicating the existence of a functional link between HIV-1 transport and uncoating.

  19. Antiretroviral (HIV-1) activity of azulene derivatives.

    Science.gov (United States)

    Peet, Julia; Selyutina, Anastasia; Bredihhin, Aleksei

    2016-04-15

    The antiretroviral activity of azulene derivatives was detected for the first time. A series of eighteen diversely substituted azulenes was synthesized and tested in vitro using HIV-1 based virus-like particles (VLPs) and infectious HIV-1 virus in U2OS and TZM-bl cell lines. Among the compounds tested, the 2-hydroxyazulenes demonstrated the most significant activity by inhibiting HIV-1 replication with IC50 of 2-10 and 8-20 μM for the VLPs and the infectious virus, respectively. These results indicate that azulene derivatives may be potentially useful candidates for the development of antiretroviral agents.

  20. Molecular Understanding of HIV-1 Latency

    Directory of Open Access Journals (Sweden)

    W. Abbas

    2012-01-01

    Full Text Available The introduction of highly active antiretroviral therapy (HAART has been an important breakthrough in the treatment of HIV-1 infection and has also a powerful tool to upset the equilibrium of viral production and HIV-1 pathogenesis. Despite the advent of potent combinations of this therapy, the long-lived HIV-1 reservoirs like cells from monocyte-macrophage lineage and resting memory CD4+ T cells which are established early during primary infection constitute a major obstacle to virus eradication. Further HAART interruption leads to immediate rebound viremia from latent reservoirs. This paper focuses on the essentials of the molecular mechanisms for the establishment of HIV-1 latency with special concern to present and future possible treatment strategies to completely purge and target viral persistence in the reservoirs.

  1. HIV-1 target cells in the CNS

    OpenAIRE

    Joseph, Sarah B.; Arrildt, Kathryn T.; Sturdevant, Christa B.; Swanstrom, Ronald

    2014-01-01

    HIV-1 replication in the central nervous system (CNS) is typically limited by the availability of target cells. HIV-1 variants that are transmitted and dominate the early stages of infection almost exclusively use the CCR5 coreceptor and are well adapted to entering, and thus infecting, cells expressing high CD4 densities similar to those found on CD4+ T cells. While the “immune privileged” CNS is largely devoid of CD4+ T cells, macrophage and microglia are abundant throughout ...

  2. HIV-1 transmission linkage in an HIV-1 prevention clinical trial

    Energy Technology Data Exchange (ETDEWEB)

    Leitner, Thomas [Los Alamos National Laboratory; Campbell, Mary S [UNIV OF WASHINGTON; Mullins, James I [UNIV OF WASHINGTON; Hughes, James P [UNIV OF WASHINGTON; Wong, Kim G [UNIV OF WASHINGTON; Raugi, Dana N [UNIV OF WASHINGTON; Scrensen, Stefanie [UNIV OF WASHINGTON

    2009-01-01

    HIV-1 sequencing has been used extensively in epidemiologic and forensic studies to investigate patterns of HIV-1 transmission. However, the criteria for establishing genetic linkage between HIV-1 strains in HIV-1 prevention trials have not been formalized. The Partners in Prevention HSV/HIV Transmission Study (ClinicaITrials.gov NCT00194519) enrolled 3408 HIV-1 serodiscordant heterosexual African couples to determine the efficacy of genital herpes suppression with acyclovir in reducing HIV-1 transmission. The trial analysis required laboratory confirmation of HIV-1 linkage between enrolled partners in couples in which seroconversion occurred. Here we describe the process and results from HIV-1 sequencing studies used to perform transmission linkage determination in this clinical trial. Consensus Sanger sequencing of env (C2-V3-C3) and gag (p17-p24) genes was performed on plasma HIV-1 RNA from both partners within 3 months of seroconversion; env single molecule or pyrosequencing was also performed in some cases. For linkage, we required monophyletic clustering between HIV-1 sequences in the transmitting and seroconverting partners, and developed a Bayesian algorithm using genetic distances to evaluate the posterior probability of linkage of participants sequences. Adjudicators classified transmissions as linked, unlinked, or indeterminate. Among 151 seroconversion events, we found 108 (71.5%) linked, 40 (26.5%) unlinked, and 3 (2.0%) to have indeterminate transmissions. Nine (8.3%) were linked by consensus gag sequencing only and 8 (7.4%) required deep sequencing of env. In this first use of HIV-1 sequencing to establish endpoints in a large clinical trial, more than one-fourth of transmissions were unlinked to the enrolled partner, illustrating the relevance of these methods in the design of future HIV-1 prevention trials in serodiscordant couples. A hierarchy of sequencing techniques, analysis methods, and expert adjudication contributed to the linkage

  3. Overcoming HIV-1 resistance to RNA interference.

    Science.gov (United States)

    Boden, Daniel; Pusch, Oliver; Ramratnam, Bharat

    2007-05-01

    RNAi refers to the sequence-specific degradation of RNA that follows the cellular introduction of homologous short interfering (si) RNA. RNAi has emerged as a powerful tool to probe the function of genes of known sequence in vitro and in vivo. Advances in vector design permit the effective expression of siRNA in human cells. Numerous recent investigations have described the ability of RNAi to decrease the replication of human immunodeficiency virus type 1 (HIV-1) in lymphocytic cells using siRNA targeting viral (e.g. tat, gag, rev) and host (e.g. CCR5, CD4) proteins. Can RNAi be used as a form of genetic therapy for HIV-1 infection? Recent data indicate that the dynamic replication kinetics of HIV-1 pose a considerable barrier to achieving durable virus suppression by RNAi with the rapid emergence of HIV-1 mutants resistant to siRNA. This review summarizes recent work on HIV-1 specific RNAi with a focus on potential strategies to overcome HIV-1 resistance to RNAi.

  4. Exosomes: Implications in HIV-1 Pathogenesis.

    Science.gov (United States)

    Madison, Marisa N; Okeoma, Chioma M

    2015-07-20

    Exosomes are membranous nanovesicles of endocytic origin that carry host and pathogen derived genomic, proteomic, and lipid cargos. Exosomes are secreted by most cell types into the extracellular milieu and are subsequently internalized by recipient cells. Upon internalization, exosomes condition recipient cells by donating their cargos and/or activating various signal transduction pathways, consequently regulating physiological and pathophysiological processes. The role of exosomes in viral pathogenesis, especially human immunodeficiency virus type 1 [HIV-1] is beginning to unravel. Recent research reports suggest that exosomes from various sources play important but different roles in the pathogenesis of HIV-1. From these reports, it appears that the source of exosomes is the defining factor for the exosomal effect on HIV-1. In this review, we will describe how HIV-1 infection is modulated by exosomes and in turn how exosomes are targeted by HIV-1 factors. Finally, we will discuss potentially emerging therapeutic options based on exosomal cargos that may have promise in preventing HIV-1 transmission.

  5. Exosomes: Implications in HIV-1 Pathogenesis

    Directory of Open Access Journals (Sweden)

    Marisa N. Madison

    2015-07-01

    Full Text Available Exosomes are membranous nanovesicles of endocytic origin that carry host and pathogen derived genomic, proteomic, and lipid cargos. Exosomes are secreted by most cell types into the extracellular milieu and are subsequently internalized by recipient cells. Upon internalization, exosomes condition recipient cells by donating their cargos and/or activating various signal transduction pathways, consequently regulating physiological and pathophysiological processes. The role of exosomes in viral pathogenesis, especially human immunodeficiency virus type 1 [HIV-1] is beginning to unravel. Recent research reports suggest that exosomes from various sources play important but different roles in the pathogenesis of HIV-1. From these reports, it appears that the source of exosomes is the defining factor for the exosomal effect on HIV-1. In this review, we will describe how HIV-1 infection is modulated by exosomes and in turn how exosomes are targeted by HIV-1 factors. Finally, we will discuss potentially emerging therapeutic options based on exosomal cargos that may have promise in preventing HIV-1 transmission.

  6. APOBEC3G-induced hypermutation of human immunodeficiency virus type-1 is typically a discrete "all or nothing" phenomenon

    DEFF Research Database (Denmark)

    Armitage, Andrew E; Deforche, Koen; Chang, Chih-Hao;

    2012-01-01

    are ∼10-fold lower than the lowest observed hypermutation levels in vitro and in vivo. Our results suggest that even a single incorporated hA3G-unit is likely to cause extensive and inactivating levels of HIV hypermutation and that hypermutation therefore is typically a discrete "all or nothing...

  7. Semen Bacterial Concentrations and HIV-1 RNA Shedding Among HIV-1–Seropositive Kenyan Men

    Science.gov (United States)

    Srinivasan, Sujatha; Huang, Dandi; Ko, Daisy L.; Sanders, Eduard J.; Peshu, Norbert M.; Krieger, John N.; Muller, Charles H.; Coombs, Robert W.; Fredricks, David N.; Graham, Susan M.

    2017-01-01

    Introduction: HIV-1 is transmitted through semen from men to their sexual partners. Genital infections can increase HIV-1 RNA shedding in semen, but shedding also occurs in the absence of typical pathogens. We hypothesized that higher bacterial concentrations in semen would be associated with higher HIV-1 RNA levels. Methods: We analyzed semen samples from 42 HIV-1–seropositive Kenyan men using quantitative polymerase chain reaction (PCR) to assess bacterial concentrations and real-time PCR to measure HIV-1 RNA levels. Generalized estimation equations were used to evaluate associations between these 2 measures. Broad-range 16S rRNA gene PCR with pyrosequencing was performed on a subset of 13 samples to assess bacterial community composition. Results: Bacteria were detected in 96.6% of 88 samples by quantitative PCR. Semen bacterial concentration and HIV-1 RNA levels were correlated 0.30 (P = 0.01). The association between bacterial concentration and HIV-1 RNA detection was not significant after adjustment for antiretroviral therapy (ART) (adjusted odds ratio: 1.27, 95% CI: 0.84 to 1.91). Factors associated with semen bacterial concentration included insertive anal sex (adjusted beta 0.92, 95% CI: 0.12 to 1.73) and ART use (adjusted beta: −0.77, 95% CI: −1.50 to 0.04). Among 13 samples with pyrosequencing data, Corynebacterium spp., Staphylococcus spp., and Streptococcus spp. were most frequently detected. Conclusion: Most of these HIV-1–infected men had bacteria in their semen. ART use was associated with undetectable semen HIV-1 RNA and lower semen bacterial concentrations, whereas insertive anal sex was associated with higher bacterial concentrations. Additional studies evaluating the relationship between semen bacteria, inflammation, mucosal immunity, and HIV-1 shedding are needed to understand implications for HIV-1 transmission. PMID:27861240

  8. Specific Elimination of Latently HIV-1 Infected Cells Using HIV-1 Protease-Sensitive Toxin Nanocapsules.

    Science.gov (United States)

    Wen, Jing; Yan, Ming; Liu, Yang; Li, Jie; Xie, Yiming; Lu, Yunfeng; Kamata, Masakazu; Chen, Irvin S Y

    2016-01-01

    Anti-retroviral drugs suppress HIV-1 plasma viremia to undetectable levels; however, latent HIV-1 persists in reservoirs within HIV-1-infected patients. The silent provirus can be activated through the use of drugs, including protein kinase C activators and histone deacetylase inhibitors. This "shock" approach is then followed by "kill" of the producing cells either through direct HIV-1-induced cell death or natural immune mechanisms. However, these mechanisms are relatively slow and effectiveness is unclear. Here, we develop an approach to specifically target and kill cells that are activated early in the process of virus production. We utilize a novel nanocapsule technology whereby the ricin A chain is encapsulated in an inactive form within a polymer shell. Specificity for release of the ricin A toxin is conferred by peptide crosslinkers that are sensitive to cleavage by HIV-1 protease. By using well-established latent infection models, J-Lat and U1 cells, we demonstrate that only within an HIV-1-producing cell expressing functional HIV-1 protease will the nanocapsule release its ricin A cargo, shutting down viral and cellular protein synthesis, and ultimately leading to rapid death of the producer cell. Thus, we provide proof of principle for a novel technology to kill HIV-1-producing cells without effects on non-target cells.

  9. Can HIV-1 infection be cured?%HIV-1感染能治愈吗?

    Institute of Scientific and Technical Information of China (English)

    张兴权

    2013-01-01

    A functional HIV-1 cure has been possible now.The ideal functional HIV-1 cure should get HIV-1 infected patients to the point where drugs are not needed after combination therapy and HIV-1 RNA cannot be detected in some patients.However,a functional HIV-1 cure is not equal to a cure for HIV-1,because HIV-1 RNA can still be detected in patients' latent infected cells and related symptoms have not been resolved completely.An era of eradication cure for HIV infection will be coming with further basic and clinical studies,especially when cleaning virus reservoirs by gene modifications successfully.%目前,HIV-1感染治疗已发展到“功能性治愈”阶段,即采用联合化疗一段时间后停止用药几年内,可以使部分患者体内的病毒达到检测不出的水平.然而,这还不是治愈,因为患者的静止淋巴细胞内仍可查到病毒痕迹,患者临床症状也并未完全消失.真正的治愈还须进行更深入的基础和临床研究,特别是通过基因修饰清除病毒的藏身之地.

  10. The hunt for HIV-1 integrase inhibitors.

    Science.gov (United States)

    Lataillade, Max; Kozal, Michael J

    2006-07-01

    Currently, there are three distinct mechanistic classes of antiretrovirals: inhibitors of the HIV- 1 reverse transcriptase and protease enzymes and inhibitors of HIV entry, including receptor and coreceptor binding and cell fusion. A new drug class that inhibits the HIV-1 integrase enzyme (IN) is in development and may soon be available in the clinic. IN is an attractive drug target because it is essential for a stable and productive HIV-1 infection and there is no mammalian homologue of IN. Inhibitors of integrase enzyme (INI) block the integration of viral double-stranded DNA into the host cell's chromosomal DNA. HIV-1 integration has many potential steps that can be inhibited and several new compounds that target specific integration steps have been identified by drug developers. Recently, two INIs, GS-9137 and MK-0518, demonstrated promising early clinical trial results and have been advanced into later stage trials. In this review, we describe how IN facilitates HIV-1 integration, the needed enzyme cofactors, and the resultant byproducts created during integration. Furthermore, we review the different INIs under development, their mechanism of actions, site of IN inhibition, potency, resistance patterns, and discuss the early clinical trial results.

  11. HIV-1 Entry Inhbitors: An Overview

    Science.gov (United States)

    Kuritzkes, Daniel R.

    2009-01-01

    Purpose of review This review provides an overview of HIV-1 entry inhibitors, with a focus on chemokine receptor antagonists. Recent findings Entry of HIV-1 into target cells is an ordered multi-step process involving attachment, co-receptor binding and fusion. Inhibitors of each step have been identified and shown to have antiviral activity in clinical trials. Phase 1-2 trials of monoclonal antibodies and small-molecule attachment inhibitors have demonstrated activity in HIV-1-infected subjects, but none has progressed to later phase clinical trials. The post-attachment inhibitor ibalizumab has shown activity in phase 1 and 2 trials; further studies are anticipated. The CCR5 antagonists maraviroc (now been approved for clinical use) and vicriviroc (in phase 3 trials) have shown significant benefit in controlled trials in treatment-experienced subjects; additional CCR5 antagonists are in various stages of clinical development. Targeting CXCR4 has proven to be more challenging. Although proof of concept has been demonstrated in phase 1-2 trials of two compounds, neither proved suitable for chronic administration. Little progress has been reported in developing longer acting or orally bioavailable fusion inhibitors. Summary ACCR5 antagonist and a fusion inhibitor are approved for use as HIV-1 entry inhibitors. Development of drugs targeting other steps in HIV-1 entry is ongoing. PMID:19339945

  12. MAS NMR of HIV-1 protein assemblies

    Science.gov (United States)

    Suiter, Christopher L.; Quinn, Caitlin M.; Lu, Manman; Hou, Guangjin; Zhang, Huilan; Polenova, Tatyana

    2015-04-01

    The negative global impact of the AIDS pandemic is well known. In this perspective article, the utility of magic angle spinning (MAS) NMR spectroscopy to answer pressing questions related to the structure and dynamics of HIV-1 protein assemblies is examined. In recent years, MAS NMR has undergone major technological developments enabling studies of large viral assemblies. We discuss some of these evolving methods and technologies and provide a perspective on the current state of MAS NMR as applied to the investigations into structure and dynamics of HIV-1 assemblies of CA capsid protein and of Gag maturation intermediates.

  13. Enhanced clearance of HIV-1-infected cells by broadly neutralizing antibodies against HIV-1 in vivo.

    Science.gov (United States)

    Lu, Ching-Lan; Murakowski, Dariusz K; Bournazos, Stylianos; Schoofs, Till; Sarkar, Debolina; Halper-Stromberg, Ariel; Horwitz, Joshua A; Nogueira, Lilian; Golijanin, Jovana; Gazumyan, Anna; Ravetch, Jeffrey V; Caskey, Marina; Chakraborty, Arup K; Nussenzweig, Michel C

    2016-05-20

    Antiretroviral drugs and antibodies limit HIV-1 infection by interfering with the viral life cycle. In addition, antibodies also have the potential to guide host immune effector cells to kill HIV-1-infected cells. Examination of the kinetics of HIV-1 suppression in infected individuals by passively administered 3BNC117, a broadly neutralizing antibody, suggested that the effects of the antibody are not limited to free viral clearance and blocking new infection but also include acceleration of infected cell clearance. Consistent with these observations, we find that broadly neutralizing antibodies can target CD4(+) T cells infected with patient viruses and can decrease their in vivo half-lives by a mechanism that requires Fcγ receptor engagement in a humanized mouse model. The results indicate that passive immunotherapy can accelerate elimination of HIV-1-infected cells.

  14. Picomolar dichotomous activity of gnidimacrin against HIV-1.

    Directory of Open Access Journals (Sweden)

    Li Huang

    Full Text Available Highly active antiretroviral therapy (HAART has offered a promising approach for controlling HIV-1 replication in infected individuals. However, with HARRT, HIV-1 is suppressed rather than eradicated due to persistence of HIV-1 in latent viral reservoirs. Thus, purging the virus from latent reservoirs is an important strategy toward eradicating HIV-1 infection. In this study, we discovered that the daphnane diterpene gnidimacrin, which was previously reported to have potent anti-cancer cell activity, activated HIV-1 replication and killed persistently-infected cells at picomolar concentrations. In addition to its potential to purge HIV-1 from latently infected cells, gnidimacrin potently inhibited a panel of HIV-1 R5 virus infection of peripheral blood mononuclear cells (PBMCs at an average concentration lower than 10 pM. In contrast, gnidimacrin only partially inhibited HIV-1 ×4 virus infection of PBMCs. The strong anti-HIV-1 R5 virus activity of gnidimacrin was correlated with its effect on down-regulation of the HIV-1 coreceptor CCR5. The anti-R5 virus activity of gnidimacrin was completely abrogated by a selective protein kinase C beta inhibitor enzastaurin, which suggests that protein kinase C beta plays a key role in the potent anti-HIV-1 activity of gnidimacrin in PBMCs. In summary, these results suggest that gnidimacrin could activate latent HIV-1, specifically kill HIV-1 persistently infected cells, and inhibit R5 viruses at picomolar concentrations.

  15. Picomolar dichotomous activity of gnidimacrin against HIV-1.

    Science.gov (United States)

    Huang, Li; Ho, Phong; Yu, Jie; Zhu, Lei; Lee, Kuo-Hsiung; Chen, Chin-Ho

    2011-01-01

    Highly active antiretroviral therapy (HAART) has offered a promising approach for controlling HIV-1 replication in infected individuals. However, with HARRT, HIV-1 is suppressed rather than eradicated due to persistence of HIV-1 in latent viral reservoirs. Thus, purging the virus from latent reservoirs is an important strategy toward eradicating HIV-1 infection. In this study, we discovered that the daphnane diterpene gnidimacrin, which was previously reported to have potent anti-cancer cell activity, activated HIV-1 replication and killed persistently-infected cells at picomolar concentrations. In addition to its potential to purge HIV-1 from latently infected cells, gnidimacrin potently inhibited a panel of HIV-1 R5 virus infection of peripheral blood mononuclear cells (PBMCs) at an average concentration lower than 10 pM. In contrast, gnidimacrin only partially inhibited HIV-1 ×4 virus infection of PBMCs. The strong anti-HIV-1 R5 virus activity of gnidimacrin was correlated with its effect on down-regulation of the HIV-1 coreceptor CCR5. The anti-R5 virus activity of gnidimacrin was completely abrogated by a selective protein kinase C beta inhibitor enzastaurin, which suggests that protein kinase C beta plays a key role in the potent anti-HIV-1 activity of gnidimacrin in PBMCs. In summary, these results suggest that gnidimacrin could activate latent HIV-1, specifically kill HIV-1 persistently infected cells, and inhibit R5 viruses at picomolar concentrations.

  16. The impact of inflammation and immune activation on B cell differentiation during HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Nicolas eRuffin

    2012-01-01

    Full Text Available HIV-1 infection is characterized by continuous antigenic stimulation, chronic immune activation and impaired survival of T and B cells. A decline of resting memory B cells has previously been reported to occur in both children and adults infected with HIV-1; these cells are responsible for mounting and maintaining an adequate serological response to antigens previously encountered in life through natural infection or vaccination. Further understanding of the mechanisms leading to impaired B cell differentiation and germinal center reaction might be essential to design new HIV vaccines and therapies that could improve humoral immune responses in HIV-1 infected individuals. In the present article we summarize the literature and present our view on critical mechanisms of B cell development which are impaired during HIV-1 infection. We also discuss the impact of microbial translocation, a driving force for persistent inflammation during HIV-1 infection, on survival of terminally differentiated B cells and how the altered expression of cytokines/chemokines pivotal for communication between T and B cells in lymphoid tissues may impair formation of memory B cells.

  17. The impact of inflammation and immune activation on B cell differentiation during HIV-1 infection.

    Science.gov (United States)

    Ruffin, Nicolas; Thang, Pham Hong; Rethi, Bence; Nilsson, Anna; Chiodi, Francesca

    2011-01-01

    One important pathogenic feature of human immunodeficiency virus (HIV)-1 infection is chronic immune activation and impaired survival of T and B cells. A decline of resting memory B cells was reported to occur in both children and adults infected with HIV-1; these cells are responsible for maintaining an adequate serological response to antigens previously encountered in life through natural infection or vaccination. Further understanding of the mechanisms leading to impaired B cell differentiation and germinal center reaction might be essential to design new HIV vaccines and therapies that could improve humoral immune responses in HIV-1 infected individuals. In the present article we summarize the literature and present our view on critical mechanisms of B cell development impaired during HIV-1 infection. We also discuss the impact of microbial translocation, a driving force for persistent inflammation during HIV-1 infection, on survival of terminally differentiated B cells and how the altered expression of cytokines/chemokines pivotal for communication between T and B cells in lymphoid tissues may impair formation of memory B cells.

  18. Wound infection rates after invasive procedures in HIV-1 seropositive versus HIV-1 seronegative hemophiliacs.

    Science.gov (United States)

    Buehrer, J L; Weber, D J; Meyer, A A; Becherer, P R; Rutala, W A; Wilson, B; Smiley, M L; White, G C

    1990-01-01

    One-hundred and two patients with hemophilia A, hemophilia B, or acquired antibody to factor VIII who had undergone invasive procedures were cross referenced with patients participating in an ongoing prospective natural history study of HIV-1 infection in hemophiliacs. Matching revealed that HIV-1 status was known for 83 patients (83%) who had undergone 169 procedures between July 1979 and April 1988. Invasive procedures were classified as clean in 108 patients (63.9%), clean-contaminated in 45 (26.6%), contaminated in 2 (1.2%), and infected in 14 (8.3%). Wound infection rates by HIV-1 status were as follows (95% confidence intervals): HIV+ 1.4% (0% to 5%), HIV- 0% (0% to 9%), and procedure before testing HIV+ 1.5% (0% to 6%). There were no significant differences between the wound infection rates of HIV-positive and HIV-negative hemophiliacs nor in the wound infection rate among all three subgroups of patients (p greater than 0.5, Fisher's Exact Test). We conclude that surgery in HIV-1-infected patients who have not progressed to AIDS does not entail an increased risk of postoperative wound infections. PMID:2322041

  19. Transplanting supersites of HIV-1 vulnerability.

    Directory of Open Access Journals (Sweden)

    Tongqing Zhou

    Full Text Available One strategy for isolating or eliciting antibodies against a specific target region on the envelope glycoprotein trimer (Env of the human immunodeficiency virus type 1 (HIV-1 involves the creation of site transplants, which present the target region on a heterologous protein scaffold with preserved antibody-binding properties. If the target region is a supersite of HIV-1 vulnerability, recognized by a collection of broadly neutralizing antibodies, this strategy affords the creation of "supersite transplants", capable of binding (and potentially eliciting antibodies similar to the template collection of effective antibodies. Here we transplant three supersites of HIV-1 vulnerability, each targeted by effective neutralizing antibodies from multiple donors. To implement our strategy, we chose a single representative antibody against each of the target supersites: antibody 10E8, which recognizes the membrane-proximal external region (MPER on the HIV-1 gp41 glycoprotein; antibody PG9, which recognizes variable regions one and two (V1V2 on the HIV-1 gp120 glycoprotein; and antibody PGT128 which recognizes a glycopeptide supersite in variable region 3 (glycan V3 on gp120. We used a structural alignment algorithm to identify suitable acceptor proteins, and then designed, expressed, and tested antigenically over 100-supersite transplants in a 96-well microtiter-plate format. The majority of the supersite transplants failed to maintain the antigenic properties of their respective template supersite. However, seven of the glycan V3-supersite transplants exhibited nanomolar affinity to effective neutralizing antibodies from at least three donors and recapitulated the mannose9-N-linked glycan requirement of the template supersite. The binding of these transplants could be further enhanced by placement into self-assembling nanoparticles. Essential elements of the glycan V3 supersite, embodied by as few as 3 N-linked glycans and ∼ 25 Env residues, can be

  20. Racing with HIV-1: Challenges and Hope

    Institute of Scientific and Technical Information of China (English)

    刘树林; 郑鑫; 王玲; 凌虹; 刘桂荣

    2004-01-01

    We are racing with HIV-1, the etiologic agent for AIDS in human beings [1,2], with two possible end consequences: if we win, HIV-1 will be under our control by immunologic or therapeutic measures; if HIV-1 wins, the SIVAfrican monkeys' story would repeat in humans, i.e., only the few individuals that are not killed by the virus

  1. HIV-1 envelope trimer fusion proteins and their applications

    NARCIS (Netherlands)

    Sliepen, K.H.E.W.J.

    2016-01-01

    HIV-1 is a major threat to global health and a vaccine is not yet on the horizon. A successful HIV-1 vaccine should probably induce HIV-1 neutralizing antibodies that target the envelope glycoprotein (Env) trimer on the outside of the virion. A possible starting point for such a vaccine are soluble

  2. Therapeutics for HIV-1 reactivation from latency.

    Science.gov (United States)

    Sgarbanti, Marco; Battistini, Angela

    2013-08-01

    Intensive combined antiretroviral therapy successfully suppresses HIV-1 replication and AIDS disease progression making infection manageable, but it is unable to eradicate the virus that persists in long-lived, drug-insensitive and immune system-insensitive reservoirs thus asking for life-long treatments with problems of compliance, resistance, toxicity and cost. These limitations and recent insights into latency mechanisms have fueled a renewed effort in finding a cure for HIV-1 infection. Proposed eradication strategies involve reactivation of the latent reservoir upon induction of viral transcription followed by the elimination of reactivated virus-producing cells by viral cytopathic effect or host immune response. Several molecules identified by mechanism-directed approaches or in large-scale screenings have been proposed as latency reversing agents. Some of them have already entered clinical testing in humans but with mixed or unsatisfactory results.

  3. Intestinal microbiota and HIV-1 infection

    Directory of Open Access Journals (Sweden)

    E. B. S. M. Trindade

    2007-01-01

    Full Text Available The intestinal microbiota consists of a qualitatively and quantitatively diverse range of microorganisms dynamically interacting with the host. It is remarkably stable with regard to the presence of microorganisms and their roles which, however, can be altered due to pathological conditions, diet composition, gastrointestinal disturbances and/or drug ingestion. The present review aimed at contributing to the discussion about changes in the intestinal microbiota due to HIV-1 infection, focusing on the triad infection-microbiota-nutrition as factors that promote intestinal bacterial imbalance. Intestinal microbiota alterations can be due to the HIV-1 infection as a primary factor or the pharmacotherapy employed, or they can be one of the consequences of the disease.

  4. NKT cells in HIV-1 infection

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Natural killer T (NKT) cells are a unique T cell population that have important immunoregulatory functions and have been shown to be involved in host immunity against a range of microorganisms. It also emerges that they might play a role in HIV-1 infection, and therefore be selectively depleted during the early stages of infection. Recent studies are reviewed regarding the dynamics of NKT depletion during HIV-I infection and their recovery under highly active antiretrovirai treatment (HAART). Possible mechanisms for these changes are proposed based on the recent developments in HIV pathogenesis. Further discussions are focused on HIV's disruption of NKT activation by downregulating CDId expression on antigen presentation cells (APC). HIV-1 protein Nefis found to play the major role by interrupting the intraceilular trafficking of nascent and recycling CDId molecules.

  5. Nanochemistry-based immunotherapy for HIV-1.

    Science.gov (United States)

    Lori, F; Calarota, S A; Lisziewicz, J

    2007-01-01

    Highly active antiretroviral treatment (HAART), i.e. the combination of three or more drugs against human immunodeficiency virus type 1 (HIV-1), has greatly improved the clinical outcome of HIV-1-infected individuals. However, HAART is unable to reconstitute HIV-specific immunity and eradicate the virus. Several observations in primate models and in humans support the notion that cell-mediated immunity can control viral replication and slow disease progression. Thus, besides drugs, an immunotherapy that induces long-lasting HIV-specific T-cell responses could play a role in the treatment of HIV/AIDS. To induce such immune responses, DermaVir Patch has been developed. DermaVir consists of an HIV-1 antigen-encoding plasmid DNA that is chemically formulated in a nanoparticle. DermaVir is administered under a patch after a skin preparation that supports the delivery of the nanoparticle to Langerhans cells (LC). Epidermal LC trap and transport the nanomedicine to draining lymph nodes. While in transit, LC mature into dendritic cells (DC), which can efficiently present the DNA-encoded antigens to naïve T-cells for the induction of cellular immunity. Pre-clinical studies and Phase I clinical testing of DermaVir in HIV-1-infected individuals have demonstrated the safety and tolerability of DermaVir Patch. To further modulate cellular immunity, molecular adjuvants might be added into the nanoparticle. DermaVir Patch represents a new nanomedicine platform for immunotherapy of HIV/AIDS. In this review, the antiviral activity of DermaVir-induced cellular immunity is discussed. Furthermore, the action of some cytokines currently being tested as adjuvants are highlighted and the adjuvant effect of cytokine plasmid DNA included in the DermaVir nanoparticle is reviewed.

  6. Morphogenesis of the infectious HIV-1 virion

    Directory of Open Access Journals (Sweden)

    Jun-Ichi eSakuragi

    2011-12-01

    Full Text Available The virion of HIV-1 is spherical and viral glycoprotein spikes (gp120, gp41 protrude from its envelope. The characteristic cone-shaped core exists within the virion, caging the ribonucleoprotein (RNP complex, which is comprised of viral RNA, nucleocapsid (NC and viral enzymes. The HIV-1 virion is budded and released from the infected cell as an immature donut-shaped particle. During or immediately after release, viral protease (PR is activated and subsequently processes the viral structural protein Gag. Through this maturation process, virions acquire infectivity, but its mechanism and transition of morphology largely remain unclear. Recent technological advances in experimental devices and techniques have made it possible to closely dissect the viral production site on the cell, the exterior – or even the interior – of an individual virion, and many new aspects on virion morphology and maturation. In this manuscript, I review the morphogenesis of HIV-1 virions. I focus on several studies, including some of our recent findings, which examined virion formation and/or maturation processes. The story of novel compound, which inhibits virion maturation, and the importance of maturation research are also discussed.

  7. Nup153 and Nup98 bind the HIV-1 core and contribute to the early steps of HIV-1 replication

    Energy Technology Data Exchange (ETDEWEB)

    Di Nunzio, Francesca, E-mail: francesca.di-nunzio@pasteur.fr [Molecular Virology and Vaccinology unit, CNRS URA 3015, Department of Virology, Institut Pasteur, 25-28 rue du Dr. Roux, 75015 Paris (France); Fricke, Thomas [Department of Microbiology and Immunology, Albert Einstein College of Medicine Bronx, NY 10461 (United States); Miccio, Annarita [University of Modena e Reggio Emilia, Centro di Medicina Rigenerativa, Modena (Italy); Valle-Casuso, Jose Carlos; Perez, Patricio [Department of Microbiology and Immunology, Albert Einstein College of Medicine Bronx, NY 10461 (United States); Souque, Philippe [Molecular Virology and Vaccinology unit, CNRS URA 3015, Department of Virology, Institut Pasteur, 25-28 rue du Dr. Roux, 75015 Paris (France); Rizzi, Ermanno; Severgnini, Marco [Institute of Biomedical Technologies, CNR, Milano (Italy); Mavilio, Fulvio [University of Modena e Reggio Emilia, Centro di Medicina Rigenerativa, Modena (Italy); Genethon, Evry (France); Charneau, Pierre [Molecular Virology and Vaccinology unit, CNRS URA 3015, Department of Virology, Institut Pasteur, 25-28 rue du Dr. Roux, 75015 Paris (France); Diaz-Griffero, Felipe, E-mail: felipe.diaz-griffero@einstein.yu.edu [Department of Microbiology and Immunology, Albert Einstein College of Medicine Bronx, NY 10461 (United States)

    2013-05-25

    The early steps of HIV-1 replication involve the entry of HIV-1 into the nucleus, which is characterized by viral interactions with nuclear pore components. HIV-1 developed an evolutionary strategy to usurp the nuclear pore machinery and chromatin in order to integrate and efficiently express viral genes. In the current work, we studied the role of nucleoporins 153 and 98 (Nup153 and Nup98) in infection of human Jurkat lymphocytes by HIV-1. We showed that Nup153-depleted cells exhibited a defect in nuclear import, while depletion of Nup 98 caused a slight defect in HIV integration. To explore the biochemical viral determinants for the requirement of Nup153 and Nup98 during HIV-1 infection, we tested the ability of these nucleoporins to interact with HIV-1 cores. Our findings showed that both nucleoporins bind HIV-1 cores suggesting that this interaction is important for HIV-1 nuclear import and/or integration. Distribution analysis of integration sites in Nup153-depleted cells revealed a reduced tendency of HIV-1 to integrate in intragenic sites, which in part could account for the large infectivity defect observed in Nup153-depleted cells. Our work strongly supports a role for Nup153 in HIV-1 nuclear import and integration. - Highlights: ► We studied the role of Nup98 and Nup153 in HIV-1 infection. ► Nup98 binds the HIV-1 core and is involved in HIV-1 integration. ► Nup153 binds the HIV-1 core and is involved in HIV-1 nuclear import. ► Depletion of Nup153 decreased the integration of HIV-1 in transcriptionally active sites.

  8. Suppression of HIV-1 Infectivity by Human Glioma Cells.

    Science.gov (United States)

    Hoque, Sheikh Ariful; Tanaka, Atsushi; Islam, Salequl; Ahsan, Gias Uddin; Jinno-Oue, Atsushi; Hoshino, Hiroo

    2016-05-01

    HIV-1 infection to the central nervous system (CNS) is very common in AIDS patients. The predominant cell types infected in the brain are monocytes and macrophages, which are surrounded by several HIV-1-resistant cell types, such as astrocytes, oligodendrocytes, neurons, and microvascular cells. The effect of these HIV-1-resistant cells on HIV-1 infection is largely unknown. In this study, we examined the stability of HIV-1 cultured with several human glioblastoma cell lines, for example, NP-2, U87MG, T98G, and A172, to determine whether these HIV-1-resistant brain cells could enhance or suppress HIV-1 infection and thus modulate HIV-1 infection in the CNS. The HIV-1 titer was determined using the MAGIC-5A indicator cell line as well as naturally occurring CD4(+) T cells. We found that the stability of HIV-1 incubated with NP-2 or U87MG cells at 37°C was significantly shorter (half-life, 2.5-4 h) compared to that of HIV-1 incubated with T98G or A172 cells or in culture medium without cells (half-life, 8-18 h). The spent culture media (SCM) of NP-2 and U87MG cells had the ability to suppress both R5- and X4-HIV-1 infection by inhibiting HIV-1 attachment to target cells. This inhibitory effect was eliminated by the treatment of the SCM with chondroitinase ABC but not heparinase, suggesting that the inhibitory factor(s) secreted by NP-2 and U87MG cells was chiefly mediated by chondroitin sulfate (CS) or CS-like moiety. Thus, this study reveals that some but not all glioma cells secrete inhibitory molecules to HIV-1 infection that may contribute in lowering HIV-1 infection in the CNS in vivo.

  9. HIV-1 infection of in vitro cultured human monocytes: early events and influence of anti HIV-1 antibodies

    DEFF Research Database (Denmark)

    Arendrup, M; Olofsson, S; Nielsen, Jens Ole;

    1994-01-01

    To characterize the role of the humoral immune response on HIV-1 infection of monocytes and macrophages (M phi s) we examined the susceptibility of in vitro cultured monocyte/M phi s to various HIV-1 isolates and the influence of heterologous and particularly autologous anti HIV-1 sera on this in...

  10. Identifying the important HIV-1 recombination breakpoints.

    Directory of Open Access Journals (Sweden)

    John Archer

    Full Text Available Recombinant HIV-1 genomes contribute significantly to the diversity of variants within the HIV/AIDS pandemic. It is assumed that some of these mosaic genomes may have novel properties that have led to their prevalence, particularly in the case of the circulating recombinant forms (CRFs. In regions of the HIV-1 genome where recombination has a tendency to convey a selective advantage to the virus, we predict that the distribution of breakpoints--the identifiable boundaries that delimit the mosaic structure--will deviate from the underlying null distribution. To test this hypothesis, we generate a probabilistic model of HIV-1 copy-choice recombination and compare the predicted breakpoint distribution to the distribution from the HIV/AIDS pandemic. Across much of the HIV-1 genome, we find that the observed frequencies of inter-subtype recombination are predicted accurately by our model. This observation strongly indicates that in these regions a probabilistic model, dependent on local sequence identity, is sufficient to explain breakpoint locations. In regions where there is a significant over- (either side of the env gene or under- (short regions within gag, pol, and most of env representation of breakpoints, we infer natural selection to be influencing the recombination pattern. The paucity of recombination breakpoints within most of the envelope gene indicates that recombinants generated in this region are less likely to be successful. The breakpoints at a higher frequency than predicted by our model are approximately at either side of env, indicating increased selection for these recombinants as a consequence of this region, or at least part of it, having a tendency to be recombined as an entire unit. Our findings thus provide the first clear indication of the existence of a specific portion of the genome that deviates from a probabilistic null model for recombination. This suggests that, despite the wide diversity of recombinant forms seen in

  11. Identifying the Important HIV-1 Recombination Breakpoints

    Science.gov (United States)

    Fan, Jun; Simon-Loriere, Etienne; Arts, Eric J.; Negroni, Matteo; Robertson, David L.

    2008-01-01

    Recombinant HIV-1 genomes contribute significantly to the diversity of variants within the HIV/AIDS pandemic. It is assumed that some of these mosaic genomes may have novel properties that have led to their prevalence, particularly in the case of the circulating recombinant forms (CRFs). In regions of the HIV-1 genome where recombination has a tendency to convey a selective advantage to the virus, we predict that the distribution of breakpoints—the identifiable boundaries that delimit the mosaic structure—will deviate from the underlying null distribution. To test this hypothesis, we generate a probabilistic model of HIV-1 copy-choice recombination and compare the predicted breakpoint distribution to the distribution from the HIV/AIDS pandemic. Across much of the HIV-1 genome, we find that the observed frequencies of inter-subtype recombination are predicted accurately by our model. This observation strongly indicates that in these regions a probabilistic model, dependent on local sequence identity, is sufficient to explain breakpoint locations. In regions where there is a significant over- (either side of the env gene) or under- (short regions within gag, pol, and most of env) representation of breakpoints, we infer natural selection to be influencing the recombination pattern. The paucity of recombination breakpoints within most of the envelope gene indicates that recombinants generated in this region are less likely to be successful. The breakpoints at a higher frequency than predicted by our model are approximately at either side of env, indicating increased selection for these recombinants as a consequence of this region, or at least part of it, having a tendency to be recombined as an entire unit. Our findings thus provide the first clear indication of the existence of a specific portion of the genome that deviates from a probabilistic null model for recombination. This suggests that, despite the wide diversity of recombinant forms seen in the viral

  12. Viral linkage in HIV-1 seroconverters and their partners in an HIV-1 prevention clinical trial.

    Directory of Open Access Journals (Sweden)

    Mary S Campbell

    Full Text Available BACKGROUND: Characterization of viruses in HIV-1 transmission pairs will help identify biological determinants of infectiousness and evaluate candidate interventions to reduce transmission. Although HIV-1 sequencing is frequently used to substantiate linkage between newly HIV-1 infected individuals and their sexual partners in epidemiologic and forensic studies, viral sequencing is seldom applied in HIV-1 prevention trials. The Partners in Prevention HSV/HIV Transmission Study (ClinicalTrials.gov #NCT00194519 was a prospective randomized placebo-controlled trial that enrolled serodiscordant heterosexual couples to determine the efficacy of genital herpes suppression in reducing HIV-1 transmission; as part of the study analysis, HIV-1 sequences were examined for genetic linkage between seroconverters and their enrolled partners. METHODOLOGY/PRINCIPAL FINDINGS: We obtained partial consensus HIV-1 env and gag sequences from blood plasma for 151 transmission pairs and performed deep sequencing of env in some cases. We analyzed sequences with phylogenetic techniques and developed a Bayesian algorithm to evaluate the probability of linkage. For linkage, we required monophyletic clustering between enrolled partners' sequences and a Bayesian posterior probability of ≥ 50%. Adjudicators classified each seroconversion, finding 108 (71.5% linked, 40 (26.5% unlinked, and 3 (2.0% indeterminate transmissions, with linkage determined by consensus env sequencing in 91 (84%. Male seroconverters had a higher frequency of unlinked transmissions than female seroconverters. The likelihood of transmission from the enrolled partner was related to time on study, with increasing numbers of unlinked transmissions occurring after longer observation periods. Finally, baseline viral load was found to be significantly higher among linked transmitters. CONCLUSIONS/SIGNIFICANCE: In this first use of HIV-1 sequencing to establish endpoints in a large clinical trial, more than

  13. APOBEC3F determinants of HIV-1 Vif sensitivity.

    Science.gov (United States)

    Land, Allison M; Shaban, Nadine M; Evans, Leah; Hultquist, Judd F; Albin, John S; Harris, Reuben S

    2014-11-01

    HIV-1 Vif counteracts restrictive APOBEC3 proteins by targeting them for proteasomal degradation. To determine the regions mediating sensitivity to Vif, we compared human APOBEC3F, which is HIV-1 Vif sensitive, with rhesus APOBEC3F, which is HIV-1 Vif resistant. Rhesus-human APOBEC3F chimeras and amino acid substitution mutants were tested for sensitivity to HIV-1 Vif. This approach identified the α3 and α4 helices of human APOBEC3F as important determinants of the interaction with HIV-1 Vif.

  14. HIV-1 phylogenetic analysis shows HIV-1 transits through the meninges to brain and peripheral tissues.

    Science.gov (United States)

    Lamers, Susanna L; Gray, Rebecca R; Salemi, Marco; Huysentruyt, Leanne C; McGrath, Michael S

    2011-01-01

    Brain infection by the human immunodeficiency virus type 1 (HIV-1) has been investigated in many reports with a variety of conclusions concerning the time of entry and degree of viral compartmentalization. To address these diverse findings, we sequenced HIV-1 gp120 clones from a wide range of brain, peripheral and meningeal tissues from five patients who died from several HIV-1 associated disease pathologies. High-resolution phylogenetic analysis confirmed previous studies that showed a significant degree of compartmentalization in brain and peripheral tissue subpopulations. Some intermixing between the HIV-1 subpopulations was evident, especially in patients that died from pathologies other than HIV-associated dementia. Interestingly, the major tissue harboring virus from both the brain and peripheral tissues was the meninges. These results show that (1) HIV-1 is clearly capable of migrating out of the brain, (2) the meninges are the most likely primary transport tissues, and (3) infected brain macrophages comprise an important HIV reservoir during highly active antiretroviral therapy.

  15. Tannin inhibits HIV-1 entry by targeting gp41

    Institute of Scientific and Technical Information of China (English)

    Lin L(U); Shu-wen LIU; Shi-bo JIANG; Shu-guang WU

    2004-01-01

    AIM: To investigate the mechanism by which tannin inhibits HIV-1 entry into target cells. METHODS: The inhibitory activity of tannin on HIV-1 replication and entry was detected by p24 production and HIV-1-mediated cell fusion, respectively. The inhibitory activity on the gp41 six-helix bundle formation was determined by an improved sandwich ELISA. RESULTS: Tannins from different sources showed potent inhibitory activity on HIV-1 replication,HIV-1-mediated cell fusion, and the gp4 six-helix bundle formation. CONCLUSION: Tannin inhibits HIV-1 entry into target cells by interfering with the gp41 six-helix bundle formation, thus blocking HIV-1 fusion with the target cell.

  16. Broad activation of latent HIV-1 in vivo

    DEFF Research Database (Denmark)

    Barton, Kirston; Hiener, Bonnie; Winckelmann, Anni;

    2016-01-01

    The 'shock and kill' approach to cure human immunodeficiency virus (HIV) includes transcriptional induction of latent HIV-1 proviruses using latency-reversing agents (LRAs) with targeted immunotherapy to purge infected cells. The administration of LRAs (panobinostat or vorinostat) to HIV-1-infected...... individuals on antiretroviral therapy induces a significant increase in cell-associated unspliced (CA-US) HIV-1 RNA from CD4(+) T cells. However, it is important to discern whether the increases in CA-US HIV-1 RNA are due to limited or broad activation of HIV-1 proviruses. Here we use single-genome sequencing...... to find that the RNA transcripts observed following LRA administration are genetically diverse, indicating activation of transcription from an extensive range of proviruses. Defective sequences are more frequently found in CA HIV-1 RNA than in HIV-1 DNA, which has implications for developing an accurate...

  17. Significant impact of non-B HIV-1 variants genetic diversity in Gabon on plasma HIV-1 RNA quantitation.

    Science.gov (United States)

    Mouinga-Ondémé, Augustin; Mabika-Mabika, Arsène; Alalade, Patrick; Mongo, Arnaud Delis; Sica, Jeanne; Liégeois, Florian; Rouet, François

    2014-01-01

    Evaluations of HIV-1 RNA viral load assays are lacking in Central Africa. The main objective of our study was to assess the reliability of HIV-1 RNA results obtained with three different assays for samples collected in Gabon. A total of 137 plasma specimens were assessed for HIV-1 RNA using the Abbott RealTime HIV-1® and Nuclisens HIV-1 EasyQ® version 2.0 assays. It included HIV-1 non-B samples (n = 113) representing six subtypes, 10 CRFs and 18 URFs from patients infected with HIV-1 and treated with antiretrovirals that were found HIV-1 RNA positive (≥300 copies/ml) with the Generic HIV viral load® assay; and samples (n = 24) from untreated individuals infected with HIV-1 but showing undetectable (<300 copies/ml) results with the Biocentric kit. For samples found positive with the Generic HIV viral load® test, correlation coefficients obtained between the three techniques were relatively low (R = 0.65 between Generic HIV viral load® and Abbott RealTime HIV-1®, 0.50 between Generic HIV viral load® and Nuclisens HIV-1 EasyQ®, and 0.66 between Abbott RealTime HIV-1® and Nuclisens HIV-1 EasyQ®). Discrepancies by at least one log10 were obtained for 19.6%, 33.7%, and 20% of samples, respectively, irrespective of genotype. Most of samples (22/24) from untreated study patients, found negative with the Biocentric kit, were also found negative with the two other techniques. In Central Africa, HIV-1 genetic diversity remains challenging for viral load testing. Further studies are required in the same area to confirm the presence of HIV-1 strains that are not amplified with at least two different viral load assays.

  18. Plasmacytoid dendritic cells suppress HIV-1 replication but contribute to HIV-1 induced immunopathogenesis in humanized mice.

    Directory of Open Access Journals (Sweden)

    Guangming Li

    2014-07-01

    Full Text Available The role of plasmacytoid dendritic cells (pDC in human immunodeficiency virus type 1 (HIV-1 infection and pathogenesis remains unclear. HIV-1 infection in the humanized mouse model leads to persistent HIV-1 infection and immunopathogenesis, including type I interferons (IFN-I induction, immune-activation and depletion of human leukocytes, including CD4 T cells. We developed a monoclonal antibody that specifically depletes human pDC in all lymphoid organs in humanized mice. When pDC were depleted prior to HIV-1 infection, the induction of IFN-I and interferon-stimulated genes (ISGs were abolished during acute HIV-1 infection with either a highly pathogenic CCR5/CXCR4-dual tropic HIV-1 or a standard CCR5-tropic HIV-1 isolate. Consistent with the anti-viral role of IFN-I, HIV-1 replication was significantly up-regulated in pDC-depleted mice. Interestingly, the cell death induced by the highly pathogenic HIV-1 isolate was severely reduced in pDC-depleted mice. During chronic HIV-1 infection, depletion of pDC also severely reduced the induction of IFN-I and ISGs, associated with elevated HIV-1 replication. Surprisingly, HIV-1 induced depletion of human immune cells including T cells in lymphoid organs, but not the blood, was reduced in spite of the increased viral replication. The increased cell number in lymphoid organs was associated with a reduced level of HIV-induced cell death in human leukocytes including CD4 T cells. We conclude that pDC play opposing roles in suppressing HIV-1 replication and in promoting HIV-1 induced immunopathogenesis. These findings suggest that pDC-depletion and IFN-I blockade will provide novel strategies for treating those HIV-1 immune non-responsive patients with persistent immune activation despite effective anti-retrovirus treatment.

  19. Role of endolysosomes in HIV-1 Tat-induced neurotoxicity

    Directory of Open Access Journals (Sweden)

    Liang Hui

    2012-06-01

    Full Text Available Combined anti-retroviral therapeutic drugs effectively increase the lifespan of HIV-1-infected individuals who then have a higher prevalence of HAND (HIV-1 associated neurocognitive disorder. Soluble factors including HIV-1 proteins released from HIV-1-infected cells have been implicated in the pathogenesis of HAND, and particular attention has been paid to the HIV-1 Tat (transactivator of transcription protein because of its ability to directly excite neurons and cause neuronal cell death. Since HIV-1 Tat enters cells by receptor-mediated endocytosis and since endolysosomes play an important role in neuronal cell life and death, we tested here the hypothesis that HIV-1 Tat neurotoxicity is associated with changes in the endolysosome structure and function and also autophagy. Following the treatment of primary cultured rat hippocampal neurons with HIV-1 Tat or as controls mutant-Tat or PBS, neuronal viability was determined using a triple staining method. Preceding observations of HIV-1 Tat-induced neuronal cell death, we observed statistically significant changes in the structure and membrane integrity of endolysosomes, endolysosome pH and autophagy. As early as 24 h after HIV-1 Tat was applied to neurons, HIV-1 Tat accumulated in endolysosomes, endolysosome morphology was affected and their size increased, endolysosome membrane integrity was disrupted, endolysosome pH increased, specific activities of endolysosome enzymes decreased and autophagy was inhibited, as indicated by the significant changes in three markers for autophagy. In contrast, statistically significant levels of HIV-1 Tat-induced neuronal cell death were observed only after 48 h of HIV-1 Tat treatment. Our findings suggest that endolysosomes are involved in HIV-1 Tat-induced neurotoxicity and may represent a target for therapeutic intervention against HAND.

  20. Role of Endolysosomes in HIV-1 Tat-Induced Neurotoxicity

    Directory of Open Access Journals (Sweden)

    Liang Hui

    2012-05-01

    Full Text Available Combined anti-retroviral therapeutic drugs effectively increase the lifespan of HIV-1-infected individuals who then have a higher prevalence of HAND (HIV-1 associated neurocognitive disorder. Soluble factors including HIV-1 proteins released from HIV-1-infected cells have been implicated in the pathogenesis of HAND, and particular attention has been paid to the HIV-1 Tat (transactivator of transcription protein because of its ability to directly excite neurons and cause neuronal cell death. Since HIV-1 Tat enters cells by receptor-mediated endocytosis and since endolysosomes play an important role in neuronal cell life and death, we tested here the hypothesis that HIV-1 Tat neurotoxicity is associated with changes in the endolysosome structure and function and also autophagy. Following the treatment of primary cultured rat hippocampal neurons with HIV-1 Tat or as controls mutant-Tat or PBS, neuronal viability was determined using a triple staining method. Preceding observations of HIV-1 Tat-induced neuronal cell death, we observed statistically significant changes in the structure and membrane integrity of endolysosomes, endolysosome pH and autophagy. As early as 24 h after HIV-1 Tat was applied to neurons, HIV-1 Tat accumulated in endolysosomes, endolysosome morphology was affected and their size increased, endolysosome membrane integrity was disrupted, endolysosome pH increased, specific activities of endolysosome enzymes decreased and autophagy was inhibited, as indicated by the significant changes in three markers for autophagy. In contrast, statistically significant levels of HIV-1 Tat-induced neuronal cell death were observed only after 48 h of HIV-1 Tat treatment. Our findings suggest that endolysosomes are involved in HIV-1 Tat-induced neurotoxicity and may represent a target for therapeutic intervention against HAND.

  1. Rigidity analysis of HIV-1 protease

    Energy Technology Data Exchange (ETDEWEB)

    Heal, J W [MOAC Doctoral Training Centre, University of Warwick, Coventry, CV4 7AL (United Kingdom); Wells, S A; Jimenez-Roldan, E; Roemer, R A [Department of Physics and Centre for Scientific Computing, University of Warwick, Coventry, CV4 7AL (United Kingdom); Freedman, R F, E-mail: jack.heal@warwick.ac.uk [School of Life Sciences, University of Warwick, Coventry, CV4 7AL (United Kingdom)

    2011-03-01

    We present a rigidity analysis on a large number of X-ray crystal structures of the enzyme HIV-1 protease using the 'pebble game' algorithm of the software FIRST. We find that although the rigidity profile remains similar across a comprehensive set of high resolution structures, the profile changes significantly in the presence of an inhibitor. Our study shows that the action of the inhibitors is to restrict the flexibility of the {beta}-hairpin flaps which allow access to the active site. The results are discussed in the context of full molecular dynamics simulations as well as data from NMR experiments.

  2. Cooperation of B cell lineages in induction of HIV-1-broadly neutralizing antibodies.

    Science.gov (United States)

    Gao, Feng; Bonsignori, Mattia; Liao, Hua-Xin; Kumar, Amit; Xia, Shi-Mao; Lu, Xiaozhi; Cai, Fangping; Hwang, Kwan-Ki; Song, Hongshuo; Zhou, Tongqing; Lynch, Rebecca M; Alam, S Munir; Moody, M Anthony; Ferrari, Guido; Berrong, Mark; Kelsoe, Garnett; Shaw, George M; Hahn, Beatrice H; Montefiori, David C; Kamanga, Gift; Cohen, Myron S; Hraber, Peter; Kwong, Peter D; Korber, Bette T; Mascola, John R; Kepler, Thomas B; Haynes, Barton F

    2014-07-31

    Development of strategies for induction of HIV-1 broadly neutralizing antibodies (bnAbs) by vaccines is a priority. Determining the steps of bnAb induction in HIV-1-infected individuals who make bnAbs is a key strategy for immunogen design. Here, we study the B cell response in a bnAb-producing individual and report cooperation between two B cell lineages to drive bnAb development. We isolated a virus-neutralizing antibody lineage that targeted an envelope region (loop D) and selected virus escape mutants that resulted in both enhanced bnAb lineage envelope binding and escape mutant neutralization-traits associated with increased B cell antigen drive. Thus, in this individual, two B cell lineages cooperated to induce the development of bnAbs. Design of vaccine immunogens that simultaneously drive both helper and broadly neutralizing B cell lineages may be important for vaccine-induced recapitulation of events that transpire during the maturation of neutralizing antibodies in HIV-1-infected individuals.

  3. Super-resolution imaging of ESCRT-proteins at HIV-1 assembly sites.

    Directory of Open Access Journals (Sweden)

    Jens Prescher

    2015-02-01

    Full Text Available The cellular endosomal sorting complex required for transport (ESCRT machinery is involved in membrane budding processes, such as multivesicular biogenesis and cytokinesis. In HIV-infected cells, HIV-1 hijacks the ESCRT machinery to drive HIV release. Early in the HIV-1 assembly process, the ESCRT-I protein Tsg101 and the ESCRT-related protein ALIX are recruited to the assembly site. Further downstream, components such as the ESCRT-III proteins CHMP4 and CHMP2 form transient membrane associated lattices, which are involved in virus-host membrane fission. Although various geometries of ESCRT-III assemblies could be observed, the actual membrane constriction and fission mechanism is not fully understood. Fission might be driven from inside the HIV-1 budding neck by narrowing the membranes from the outside by larger lattices surrounding the neck, or from within the bud. Here, we use super-resolution fluorescence microscopy to elucidate the size and structure of the ESCRT components Tsg101, ALIX, CHMP4B and CHMP2A during HIV-1 budding below the diffraction limit. To avoid the deleterious effects of using fusion proteins attached to ESCRT components, we performed measurements on the endogenous protein or, in the case of CHMP4B, constructs modified with the small HA tag. Due to the transient nature of the ESCRT interactions, the fraction of HIV-1 assembly sites with colocalizing ESCRT complexes was low (1.5%-3.4%. All colocalizing ESCRT clusters exhibited closed, circular structures with an average size (full-width at half-maximum between 45 and 60 nm or a diameter (determined using a Ripley's L-function analysis of roughly 60 to 100 nm. The size distributions for colocalizing clusters were narrower than for non-colocalizing clusters, and significantly smaller than the HIV-1 bud. Hence, our results support a membrane scission process driven by ESCRT protein assemblies inside a confined structure, such as the bud neck, rather than by large lattices

  4. Chronic alcohol ingestion exacerbates skeletal muscle myopathy in HIV-1 transgenic rats

    Directory of Open Access Journals (Sweden)

    Bratina Margaux A

    2011-08-01

    Full Text Available Abstract Background Separately, chronic alcohol ingestion and HIV-1 infection are associated with severe skeletal muscle derangements, including atrophy and wasting, weakness, and fatigue. One prospective cohort study reported that 41% of HIV-infected patients met the criteria for alcoholism, however; few reports exist on the co-morbid effects of these two disease processes on skeletal muscle homeostasis. Thus, we analyzed the atrophic effects of chronic alcohol ingestion in HIV-1 transgenic rats and identified alterations to several catabolic and anabolic factors. Findings Relative plantaris mass, total protein content, and fiber cross-sectional area were reduced in each experimental group compared to healthy, control-fed rats. Alcohol abuse further reduced plantaris fiber area in HIV-1 transgenic rats. Consistent with previous reports, gene levels of myostatin and its receptor activin IIB were not increased in HIV-1 transgenic rat muscle. However, myostatin and activin IIB were induced in healthy and HIV-1 transgenic rats fed alcohol for 12 weeks. Catabolic signaling factors such as TGFβ1, TNFα, and phospho-p38/total-p38 were increased in all groups compared to controls. There was no effect on IL-6, leukemia inhibitory factor (LIF, cardiotrophin-1 (CT-1, or ciliary neurotrophic factor (CNTF in control-fed, transgenic rats. However, the co-morbidity of chronic alcohol abuse and HIV-1-related protein expression decreased expression of the two anabolic factors, CT-1 and CNTF. Conclusions Consistent with previous reports, alcohol abuse accentuated skeletal muscle atrophy in an animal model of HIV/AIDS. While some catabolic pathways known to drive alcoholic or HIV-1-associated myopathies were also elevated in this co-morbid model (e.g., TGFβ1, consistent expression patterns were not apparent. Thus, specific alterations to signaling mechanisms such as the induction of the myostatin/activin IIB system or reductions in growth factor signaling via

  5. Mechanism of HIV-1 recombination%HIV-1重组机制

    Institute of Scientific and Technical Information of China (English)

    姚瑾; 李佩璐; 张驰宇

    2013-01-01

    HIV is a retrovirus, which contains two copies of plus-strand RNA genome. During synthesis of provirus DNA, the reverse transcriptase template switching that causes HIV genetic recombination occurs between two genomic RNAs. This genetic recombination plays a central role in shaping HIV diversity, and brings great challenges in HIV diagnosis, therapy and vaccine development. Here, we review the recent advances on HIV-1 recombination and discuss the effects on HIV-1 prevention and control.%人类免疫缺陷病毒(HIV)属于逆转录病毒,包含2个正链的RNA基因组.其复制过程需要逆转录酶发生模板转换,这样极容易导致重组.重组是导致HIV多样性的重要原因,给病毒的诊断、治疗以及疫苗研发带来巨大困难.本文综述了HIV-1重组的条件、机制、特性以及重组对于HIV-1防控和疫苗研究的影响.

  6. Fucoidans as Potential Inhibitors of HIV-1

    Science.gov (United States)

    Prokofjeva, Maria M.; Imbs, Tatyana I.; Shevchenko, Natalya M.; Spirin, Pavel V.; Horn, Stefan; Fehse, Boris; Zvyagintseva, Tatyana N.; Prassolov, Vladimir S.

    2013-01-01

    The antiviral activity of different structure fucoidans (α-l-fucans and galactofucans) was studied using two model viral systems based on a lentiviral vectors and a replication competent Moloney murine leukemia virus (Mo-MuLV). It was found that investigated fucoidans have no cytotoxic effects on Jurkat and SC-1cell at the concentration range of 0.001–100 µg/mL. Fucoidans with different efficiency suppressed transduction of Jurkat cell line by pseudo-HIV-1 particles carrying the envelope protein of HIV-1 and infection of SC-1 cells by Mo-MuLV. According to our data, all natural fucoidans can be considered as potential anti-HIV agents regardless of their carbohydrate backbone and degree of sulfating, since their activity is shown at low concentrations (0.001–0.05 µg/mL). High molecular weight fucoidans isolated from Saccharina cichorioides (1.3-α-l-fucan), and S. japonica (galactofucan) were the most effective inhibitors. PMID:23966033

  7. Cyclophilin B enhances HIV-1 infection

    Energy Technology Data Exchange (ETDEWEB)

    DeBoer, Jason; Madson, Christian J. [Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE (United States); Belshan, Michael, E-mail: michaelbelshan@creighton.edu [Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE (United States); The Nebraska Center for Virology, University of Nebraska, Lincoln, NE (United States)

    2016-02-15

    Cyclophilin B (CypB) is a member of the immunophilin family and intracellular chaperone. It predominantly localizes to the ER, but also contains a nuclear localization signal and is secreted from cells. CypB has been shown to interact with the Gag protein of human immunodeficiency type 1 (HIV-1). Several proteomic and genetic studies identified it as a potential factor involved in HIV replication. Herein, we show that over-expression of CypB enhances HIV infection by increasing nuclear import of viral DNA. This enhancement was unaffected by cyclosporine treatment and requires the N-terminus of the protein. The N-terminus contains an ER leader sequence, putative nuclear localization signal, and is required for secretion. Deletion of the N-terminus resulted in mislocalization from the ER and suppression of HIV infection. Passive transfer experiments showed that secreted CypB did not impact HIV infection. Combined, these experiments show that intracellular CypB modulates a pathway of HIV nuclear import. - Highlights: • CypB has been identified in several proteomic studies of HIV-1 infection. • CypB expression is upregulated in activated and infected T-cells. • Over-expression of CypB enhances HIV nuclear import and infection. • The N-terminus of CypB is necessary for these effects.

  8. Fucoidans as Potential Inhibitors of HIV-1

    Directory of Open Access Journals (Sweden)

    Vladimir S. Prassolov

    2013-08-01

    Full Text Available The antiviral activity of different structure fucoidans (α-l-fucans and galactofucans was studied using two model viral systems based on a lentiviral vectors and a replication competent Moloney murine leukemia virus (Mo-MuLV. It was found that investigated fucoidans have no cytotoxic effects on Jurkat and SC-1cell at the concentration range of 0.001–100 µg/mL. Fucoidans with different efficiency suppressed transduction of Jurkat cell line by pseudo-HIV-1 particles carrying the envelope protein of HIV-1 and infection of SC-1 cells by Mo-MuLV. According to our data, all natural fucoidans can be considered as potential anti-HIV agents regardless of their carbohydrate backbone and degree of sulfating, since their activity is shown at low concentrations (0.001–0.05 µg/mL. High molecular weight fucoidans isolated from Saccharina cichorioides (1.3-α-l-fucan, and S. japonica (galactofucan were the most effective inhibitors.

  9. Fucoidans as potential inhibitors of HIV-1.

    Science.gov (United States)

    Prokofjeva, Maria M; Imbs, Tatyana I; Shevchenko, Natalya M; Spirin, Pavel V; Horn, Stefan; Fehse, Boris; Zvyagintseva, Tatyana N; Prassolov, Vladimir S

    2013-08-19

    The antiviral activity of different structure fucoidans (α-l-fucans and galactofucans) was studied using two model viral systems based on a lentiviral vectors and a replication competent Moloney murine leukemia virus (Mo-MuLV). It was found that investigated fucoidans have no cytotoxic effects on Jurkat and SC-1cell at the concentration range of 0.001-100 µg/mL. Fucoidans with different efficiency suppressed transduction of Jurkat cell line by pseudo-HIV-1 particles carrying the envelope protein of HIV-1 and infection of SC-1 cells by Mo-MuLV. According to our data, all natural fucoidans can be considered as potential anti-HIV agents regardless of their carbohydrate backbone and degree of sulfating, since their activity is shown at low concentrations (0.001-0.05 µg/mL). High molecular weight fucoidans isolated from Saccharina cichorioides (1.3-α-l-fucan), and S. japonica (galactofucan) were the most effective inhibitors.

  10. Broadly neutralizing antibodies: An approach to control HIV-1 infection.

    Science.gov (United States)

    Yaseen, Mahmoud Mohammad; Yaseen, Mohammad Mahmoud; Alqudah, Mohammad Ali

    2017-01-02

    Although available antiretroviral therapy (ART) has changed human immunodeficiency virus (HIV)-1 infection to a non-fatal chronic disease, the economic burden of lifelong therapy, severe adverse ART effects, daily ART adherence, and emergence of ART-resistant HIV-1 mutants require prospecting for alternative therapeutic modalities. Indeed, a growing body of evidence suggests that broadly neutralizing anti-HIV-1 antibodies (BNAbs) may offer one such feasible alternative. To evaluate their therapeutic potential in established HIV-1 infection, we sought to address recent advances in pre-clinical and clinical investigations in this area of HIV-1 research. In addition, we addressed the obstacles that may impede the success of such immunotherapeutic approach, suggested strategic solutions, and briefly compared this approach with the currently used ART to open new insights for potential future passive immunotherapy for HIV-1 infection.

  11. Comprehensive Characterization of HIV-1 Molecular Epidemiology and Demographic History in the Brazilian Region Most Heavily Affected by AIDS

    Science.gov (United States)

    Machado Fritsch, Hegger; de Medeiros, Rúbia Marília; Maletich Junqueira, Dennis; Esteves de Matos Almeida, Sabrina; Pinto, Aguinaldo Roberto

    2016-01-01

    ABSTRACT The high incidence of AIDS cases and the dominance of HIV-1 subtype C infections are two features that distinguish the HIV-1 epidemic in the two southernmost Brazilian states (Rio Grande do Sul [RS] and Santa Catarina [SC]) from the epidemic in other parts of the country. Nevertheless, previous studies on HIV molecular epidemiology were conducted mainly in capital cities, and a more comprehensive understanding of factors driving this unique epidemic in Brazil is necessary. Blood samples were collected from individuals in 13 municipalities in the Brazilian southern region. HIV-1 env and pol genes were submitted to phylogenetic analyses for assignment of subtype, and viral population phylodynamics were reconstructed by applying Skygrid and logistic coalescent models in a Bayesian analysis. A high prevalence of subtype C was observed in all sampled locations; however, an increased frequency of recombinant strains was found in RS, with evidence for new circulating forms (CRFs). In the SC state, subtype B and C epidemics were associated with distinct exposure groups. Although logistic models estimated similar growth rates for HIV-1 subtype C (HIV-1C) and HIV-1B, a Skygrid plot reveals that the former epidemic has been expanding for a longer time. Our results highlight a consistent expansion of HIV-1C in south Brazil, and we also discuss how heterosexual and men who have sex with men (MSM) transmission chains might have impacted the current prevalence of HIV-1 subtypes in this region. IMPORTANCE The AIDS epidemic in south Brazil is expanding rapidly, but the circumstances driving this condition are not well known. A high prevalence of HIV-1 subtype C was reported in the capital cities of this region, in contrast to the subtype B dominance in the rest of the country. This study sought to comparatively investigate the HIV-1 subtype B and C epidemics by sampling individuals from several cities in the two states with the highest AIDS incidences in Brazil. Our

  12. Kaposi's-sarcoma-associated-herpesvirus-activated dendritic cells promote HIV-1 trans-infection and suppress CD4{sup +} T cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wan; Qin, Yan; Bai, Lei [Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, the Chinese Academy of Sciences, Shanghai (China); Graduate School of the Chinese Academy of Sciences, Beijing (China); Lan, Ke [Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, the Chinese Academy of Sciences, Shanghai (China); Wang, Jian-Hua, E-mail: Jh_wang@sibs.ac.cn [Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, the Chinese Academy of Sciences, Shanghai (China)

    2013-06-05

    Infection of Kaposi's sarcoma-associated herpesvirus (KSHV) is commonly occurred in AIDS patients. KSHV and HIV-1 act cooperatively in regulating infection with each other and in human carcinogenesis. Dendritic cells (DCs), as the pivotal cells in host immunity, may be modulated by both viruses, for immunoevasion and dissemination, therefore, the interaction between DCs and each virus has been a prior focus for pathogenesis elucidation. Here, we assessed the potential effect of KSHV on DC–HIV-1 interaction. We found that KSHV stimulation could promote maturation of monocyte-derived DCs (MDDCs) and impaired the ability of MDDCs to drive proliferation of resting CD4{sup +} T cells, demonstrating the immunosuppression induced by KSHV. More importantly, KSHV-stimulated MDDCs could capture more HIV-1 and efficiently transferred these infectious viruses to Hut/CCR5 T cell line. Our results reveal the novel modulation of DC-mediated HIV-1 dissemination by KSHV, and highlight the importance of studying DC–HIV-1 interaction to elucidate HIV/AIDS pathogenesis. - Highlights: ► KSHV impaired the ability of MDDCs to drive proliferation of resting CD4{sup +} T cells. ► KSHV stimulation matured MDDCs and enhanced HIV-1 endocytosis. ► KSHV stimulated MDDCs increased ICAM-1 expression and tighten contact with T cells. ► KSHV-stimulated MDDCs promoted HIV-1 trans-infection of CD4{sup +} T cells.

  13. Methamphetamine Enhances HIV-1 Infectivity in Monocyte Derived Dendritic Cells

    OpenAIRE

    2008-01-01

    The US is currently experiencing an epidemic of methamphetamine (Meth) use as a recreational drug. Recent studies also show a high prevalence of HIV-1 infection among Meth users. We report that Meth enhances HIV-1 infectivity of dendritic cells as measured by multinuclear activation of a galactosidase indicator (MAGI) cell assay, p24 assay, and LTR-RU5 amplification. Meth induces increased HIV-1 infection in association with an increase in the HIV-1 coreceptors, CXCR4 and CCR5, and infection ...

  14. Platelets and HIV-1 infection: old and new aspects.

    Science.gov (United States)

    Torre, Donato; Pugliese, Agostino

    2008-09-01

    In this review we summarize the data on interaction of platelets with HIV-1 infection. Thrombocytopenia is a common finding among HIV-1 infected patients; several combined factors contribute to low peripheral platelet counts, which are present during all the stages of the disease. In addition, a relationship between platelet count, plasma viral load and disease progression has been reported, and this shows the potential influence platelets may have on the natural history of HIV-1 disease. Several lines of evidence have shown that platelets are an integral part of inflammation, and can be also potent effector cells of innate immune response as well as of adaptive immunity. Thus, we rewieved the role of inflammatory cytokines, and chemokines as activators of platelets during HIV-1 infection. Moreover, platelets show a direct interaction with HIV-1 itself, through different pathogenic mechanisms as binding, engulfment, internalisation of HIV-1, playing a role in host defence during HIV-1 infection, by limiting viral spread and probably by inactivating viral particles. Platelets may also play an intriguing role on endothelial dysfunction present in HIV-1 infection, and this topic begins to receive systematic study, inasmuch as interaction between platelets and endothelial cells is important in the pathogenesis of atherosclerosis in HIV-1 infected patients, especially in those patients treated with antiretroviral drugs. Finally, this review attempts to better define the state of this emerging issue, to focus areas of potential clinical relevance, and to suggest several directions for future research.

  15. TIM-family proteins inhibit HIV-1 release.

    Science.gov (United States)

    Li, Minghua; Ablan, Sherimay D; Miao, Chunhui; Zheng, Yi-Min; Fuller, Matthew S; Rennert, Paul D; Maury, Wendy; Johnson, Marc C; Freed, Eric O; Liu, Shan-Lu

    2014-09-02

    Accumulating evidence indicates that T-cell immunoglobulin (Ig) and mucin domain (TIM) proteins play critical roles in viral infections. Herein, we report that the TIM-family proteins strongly inhibit HIV-1 release, resulting in diminished viral production and replication. Expression of TIM-1 causes HIV-1 Gag and mature viral particles to accumulate on the plasma membrane. Mutation of the phosphatidylserine (PS) binding sites of TIM-1 abolishes its ability to block HIV-1 release. TIM-1, but to a much lesser extent PS-binding deficient mutants, induces PS flipping onto the cell surface; TIM-1 is also found to be incorporated into HIV-1 virions. Importantly, TIM-1 inhibits HIV-1 replication in CD4-positive Jurkat cells, despite its capability of up-regulating CD4 and promoting HIV-1 entry. In addition to TIM-1, TIM-3 and TIM-4 also block the release of HIV-1, as well as that of murine leukemia virus (MLV) and Ebola virus (EBOV); knockdown of TIM-3 in differentiated monocyte-derived macrophages (MDMs) enhances HIV-1 production. The inhibitory effects of TIM-family proteins on virus release are extended to other PS receptors, such as Axl and RAGE. Overall, our study uncovers a novel ability of TIM-family proteins to block the release of HIV-1 and other viruses by interaction with virion- and cell-associated PS. Our work provides new insights into a virus-cell interaction that is mediated by TIMs and PS receptors.

  16. Reverse transcription of the HIV-1 pandemic.

    Science.gov (United States)

    Basavapathruni, Aravind; Anderson, Karen S

    2007-12-01

    The HIV/AIDS pandemic has existed for >25 years. Extensive work globally has provided avenues to combat viral infection, but the disease continues to rage on in the human population and infected approximately 4 million people in 2006 alone. In this review, we provide a brief history of HIV/AIDS, followed by analysis of one therapeutic target of HIV-1: its reverse transcriptase (RT). We discuss the biochemical characterization of RT in order to place emphasis on possible avenues of inhibition, which now includes both nucleoside and non-nucleoside modalities. Therapies against RT remain a cornerstone of anti-HIV treatment, but the virus eventually resists inhibition through the selection of drug-resistant RT mutations. Current inhibitors and associated resistance are discussed, with the hopes that new therapeutics can be developed against RT.

  17. Tracing the origin and northward dissemination dynamics of HIV-1 subtype C in Brazil.

    Directory of Open Access Journals (Sweden)

    Edson Delatorre

    Full Text Available Previous studies indicate that the HIV-1 subtype C epidemic in southern Brazil was initiated by the introduction of a single founder strain probably originating from east Africa. However, the exact country of origin of such a founder strain as well as the origin of the subtype C viruses detected outside the Brazilian southern region remains unknown. HIV-1 subtype C pol sequences isolated in the southern, southeastern and central-western Brazilian regions (n = 209 were compared with a large number (n ~ 2,000 of subtype C pol sequences of African origin. Maximum-likelihood analyses revealed that most HIV-1 subtype C Brazilian sequences branched in a single monophyletic clade (CBR-I, nested within a larger monophyletic lineage characteristic of east Africa. Bayesian analyses indicate that the CBR-I clade most probably originated in Burundi and was introduced into the Paraná state (southern region around the middle 1970s, after which it rapidly disseminated to neighboring regions. The states of Paraná and Santa Catarina have been the most important hubs of subtype C dissemination, and routine travel and spatial accessibility seems to have been the major driving forces of this process. Five additional introductions of HIV-1 subtype C strains probably originated in eastern (n = 2, southern (n = 2 and central (n = 1 African countries were detected in the Rio de Janeiro state (southeastern region. These results indicate a continuous influx of HIV-1 subtype C strains of African origin into Brazil and also unveil the existence of unrecognized transmission networks linking this country to east Africa.

  18. Short-Term Dynamic and Local Epidemiological Trends in the South American HIV-1B Epidemic.

    Science.gov (United States)

    Junqueira, Dennis Maletich; de Medeiros, Rubia Marília; Gräf, Tiago; Almeida, Sabrina Esteves de Matos

    2016-01-01

    The human displacement and sexual behavior are the main factors driving the HIV-1 pandemic to the current profile. The intrinsic structure of the HIV transmission among different individuals has valuable importance for the understanding of the epidemic and for the public health response. The aim of this study was to characterize the HIV-1 subtype B (HIV-1B) epidemic in South America through the identification of transmission links and infer trends about geographical patterns and median time of transmission between individuals. Sequences of the protease and reverse transcriptase coding regions from 4,810 individuals were selected from GenBank. Maximum likelihood phylogenies were inferred and submitted to ClusterPicker to identify transmission links. Bayesian analyses were applied only for clusters including ≥5 dated samples in order to estimate the median maximum inter-transmission interval. This study analyzed sequences sampled from 12 South American countries, from individuals of different exposure categories, under different antiretroviral profiles, and from a wide period of time (1989-2013). Continentally, Brazil, Argentina and Venezuela were revealed important sites for the spread of HIV-1B among countries inside South America. Of note, from all the clusters identified about 70% of the HIV-1B infections are primarily occurring among individuals living in the same geographic region. In addition, these transmissions seem to occur early after the infection of an individual, taking in average 2.39 years (95% CI 1.48-3.30) to succeed. Homosexual/Bisexual individuals transmit the virus as quickly as almost half time of that estimated for the general population sampled here. Public health services can be broadly benefitted from this kind of information whether to focus on specific programs of response to the epidemic whether as guiding of prevention campaigns to specific risk groups.

  19. Striking HIV-1 Entry by Targeting HIV-1 gp41. But, Where Should We Target?

    Directory of Open Access Journals (Sweden)

    Cátia Teixeira

    Full Text Available HIV-1 gp41 facilitates the viral fusion through a conformational switch involving the association of three C-terminal helices along the conserved hydrophobic grooves of three N-terminal helices coiled-coil. The control of these structural rearrangements is thought to be central to HIV-1 entry and, therefore, different strategies of intervention are being developed. Herewith, we describe a procedure to simulate the folding of an HIV-1 gp41 simplified model. This procedure is based on the construction of plausible conformational pathways, which describe protein transition between non-fusogenic and fusogenic conformations. The calculation of the paths started with 100 molecular dynamics simulations of the non-fusogenic conformation, which were found to converge to different intermediate states. Those presenting defined criteria were selected for separate targeted molecular dynamics simulations, subjected to a force constant imposing a movement towards the gp41 fusogenic conformation. Despite significant diversity, a preferred sequence of events emerged when the simulations were analyzed in terms of the formation, breakage and evolution of the contacts. We pointed out 29 residues as the most relevant for the movement of gp41; also, 2696 possible interactions were reduced to only 48 major interactions, which reveals the efficiency of the method. The analysis of the evolution of the main interactions lead to the detection of four main behaviors for those contacts: stable, increasing, decreasing and repulsive interactions. Altogether, these results suggest a specific small cavity of the HIV-1 gp41 hydrophobic groove as the preferred target to small molecules.

  20. Stable assembly of HIV-1 export complexes occurs cotranscriptionally

    DEFF Research Database (Denmark)

    Nawroth, Isabel; Mueller, Florian; Basyuk, Eugenia

    2014-01-01

    The HIV-1 Rev protein mediates export of unspliced and singly spliced viral transcripts by binding to the Rev response element (RRE) and recruiting the cellular export factor CRM1. Here, we investigated the recruitment of Rev to the transcription sites of HIV-1 reporters that splice either post- ...

  1. Varicella vaccination in HIV-1-infected children after immune reconstitution

    NARCIS (Netherlands)

    V. Bekker; G.H.A. Westerlaken; H. Scherpbier; S. Alders; H. Zaaijer; D. van Baarle; T. Kuijper

    2006-01-01

    Background: HIV-1-infected children have an increased risk of severe chickenpox. However, vaccination is not recommended in severely immunocompromised children. Objective: Can the live-attenuated varicella zoster virus (VZV) Oka strain be safely and effectively given to HIV-1-infected children despi

  2. [A new unique HIV-1 recombinant form detected in Belarus].

    Science.gov (United States)

    Eremin, V F; Gasich, E L; Sosinovich, S V

    2012-01-01

    Republican Research-and-Practical Center for Epidemiology and Microbiology, Ministry of Health of Belarus, Minsk The paper presents data on the molecular genetic characteristics of a new HIV-1 recombinant form. The study has shown that the virus is referred to as HIV-1 subtype B in terms of the gag gene and HIV-1 subtype A in terms of the pol and env genes. At the same time the new isolate is closer, in terms of the gag gene, to the HIV-1 DQ207943 strain isolated in Georgia, in terms of the pol gene, to the HIV-1 AF413987.1 strain isolated in Ukraine and, in terms of the env gene to the HIV-1 AY500393 strain isolated in Russia. Thus, the described new HIV-1 recombinant form has the following structure: BgagApolAenv. The gag, pol, and env gene sequences from the new unique HIV-1 recombinant form have been registered in the international database EMBL/Genbank/DDBJ under accession numbers FR775442.1, FN995656.1, and FR775443.1.

  3. Global human genetics of HIV-1 infection and China

    Institute of Scientific and Technical Information of China (English)

    Tuo Fu ZHU; Tie Jian FENG; Xin XIAO; Hui WANG; Bo Ping ZHOU

    2005-01-01

    Genetic polymorphisms in human genes can influence the risk for HIV-1 infection and disease progression, although the reported effects of these alleles have been inconsistent. This review highlights the recent discoveries on global and Chinese genetic polymorphisms and their association with HIV-1 transmission and disease progression.

  4. Antibody function in neutralization and protection against HIV-1

    NARCIS (Netherlands)

    Hessell, A.J.

    2009-01-01

    The ability to induce neutralizing antibodies is generally thought to be of great importance for vaccine efficacy. In HIV-1 research this quality has been elusive as the HIV-1 virus has evolved multiple mechanisms to evade neutralizing antibodies. This thesis traces studies with four broadly neutral

  5. Antiviral Therapy by HIV-1 Broadly Neutralizing and Inhibitory Antibodies

    Directory of Open Access Journals (Sweden)

    Zhiqing Zhang

    2016-11-01

    Full Text Available Human immunodeficiency virus type 1 (HIV-1 infection causes acquired immune deficiency syndrome (AIDS, a global epidemic for more than three decades. HIV-1 replication is primarily controlled through antiretroviral therapy (ART but this treatment does not cure HIV-1 infection. Furthermore, there is increasing viral resistance to ART, and side effects associated with long-term therapy. Consequently, there is a need of alternative candidates for HIV-1 prevention and therapy. Recent advances have discovered multiple broadly neutralizing antibodies against HIV-1. In this review, we describe the key epitopes on the HIV-1 Env protein and the reciprocal broadly neutralizing antibodies, and discuss the ongoing clinical trials of broadly neutralizing and inhibitory antibody therapy as well as antibody combinations, bispecific antibodies, and methods that improve therapeutic efficacy by combining broadly neutralizing antibodies (bNAbs with latency reversing agents. Compared with ART, HIV-1 therapeutics that incorporate these broadly neutralizing and inhibitory antibodies offer the advantage of decreasing virus load and clearing infected cells, which is a promising prospect in HIV-1 prevention and treatment.

  6. Antiviral Therapy by HIV-1 Broadly Neutralizing and Inhibitory Antibodies.

    Science.gov (United States)

    Zhang, Zhiqing; Li, Shaowei; Gu, Ying; Xia, Ningshao

    2016-11-18

    Human immunodeficiency virus type 1 (HIV-1) infection causes acquired immune deficiency syndrome (AIDS), a global epidemic for more than three decades. HIV-1 replication is primarily controlled through antiretroviral therapy (ART) but this treatment does not cure HIV-1 infection. Furthermore, there is increasing viral resistance to ART, and side effects associated with long-term therapy. Consequently, there is a need of alternative candidates for HIV-1 prevention and therapy. Recent advances have discovered multiple broadly neutralizing antibodies against HIV-1. In this review, we describe the key epitopes on the HIV-1 Env protein and the reciprocal broadly neutralizing antibodies, and discuss the ongoing clinical trials of broadly neutralizing and inhibitory antibody therapy as well as antibody combinations, bispecific antibodies, and methods that improve therapeutic efficacy by combining broadly neutralizing antibodies (bNAbs) with latency reversing agents. Compared with ART, HIV-1 therapeutics that incorporate these broadly neutralizing and inhibitory antibodies offer the advantage of decreasing virus load and clearing infected cells, which is a promising prospect in HIV-1 prevention and treatment.

  7. The origin and emergence of an HIV-1 epidemic:

    DEFF Research Database (Denmark)

    Bruhn, Christian Anders Wathne; Audelin, Anne M.; Helleberg, Marie;

    2014-01-01

    To describe, at patient-level detail, the determining events and factors involved in the development of a country's HIV-1 epidemic.......To describe, at patient-level detail, the determining events and factors involved in the development of a country's HIV-1 epidemic....

  8. Molecular Mechanisms in Activation of Latent HIV-1

    NARCIS (Netherlands)

    H. Rafati (Haleh)

    2014-01-01

    markdownabstract__Abstract__ Finding a cure for the human immunodeficiency virus type 1 (HIV-1) is extremely challenging. Development of highly active anti-retroviral therapy (HAART), transformed HIV-1 infection from an acute syndrome into chronic disease. Although using HAART results in suppressio

  9. Modeling HIV-1 drug resistance as episodic directional selection.

    Directory of Open Access Journals (Sweden)

    Ben Murrell

    Full Text Available The evolution of substitutions conferring drug resistance to HIV-1 is both episodic, occurring when patients are on antiretroviral therapy, and strongly directional, with site-specific resistant residues increasing in frequency over time. While methods exist to detect episodic diversifying selection and continuous directional selection, no evolutionary model combining these two properties has been proposed. We present two models of episodic directional selection (MEDS and EDEPS which allow the a priori specification of lineages expected to have undergone directional selection. The models infer the sites and target residues that were likely subject to directional selection, using either codon or protein sequences. Compared to its null model of episodic diversifying selection, MEDS provides a superior fit to most sites known to be involved in drug resistance, and neither one test for episodic diversifying selection nor another for constant directional selection are able to detect as many true positives as MEDS and EDEPS while maintaining acceptable levels of false positives. This suggests that episodic directional selection is a better description of the process driving the evolution of drug resistance.

  10. HIV-1 differentially modulates autophagy in neurons and astrocytes.

    Science.gov (United States)

    Mehla, Rajeev; Chauhan, Ashok

    2015-08-15

    Autophagy, a lysosomal degradative pathway that maintains cellular homeostasis, has emerged as an innate immune defense against pathogens. The role of autophagy in the deregulated HIV-infected central nervous system (CNS) is unclear. We have found that HIV-1-induced neuro-glial (neurons and astrocytes) damage involves modulation of the autophagy pathway. Neuro-glial stress induced by HIV-1 led to biochemical and morphological dysfunctions. X4 HIV-1 produced neuro-glial toxicity coupled with suppression of autophagy, while R5 HIV-1-induced toxicity was restricted to neurons. Rapamycin, a specific mTOR inhibitor (autophagy inducer) relieved the blockage of the autophagy pathway caused by HIV-1 and resulted in neuro-glial protection. Further understanding of the regulation of autophagy by cytokines and chemokines or other signaling events may lead to recognition of therapeutic targets for neurodegenerative diseases.

  11. The Depsipeptide Romidepsin Reverses HIV-1 Latency In Vivo.

    Directory of Open Access Journals (Sweden)

    Ole S Søgaard

    2015-09-01

    Full Text Available Pharmacologically-induced activation of replication competent proviruses from latency in the presence of antiretroviral treatment (ART has been proposed as a step towards curing HIV-1 infection. However, until now, approaches to reverse HIV-1 latency in humans have yielded mixed results. Here, we report a proof-of-concept phase Ib/IIa trial where 6 aviremic HIV-1 infected adults received intravenous 5 mg/m2 romidepsin (Celgene once weekly for 3 weeks while maintaining ART. Lymphocyte histone H3 acetylation, a cellular measure of the pharmacodynamic response to romidepsin, increased rapidly (maximum fold range: 3.7–7.7 relative to baseline within the first hours following each romidepsin administration. Concurrently, HIV-1 transcription quantified as copies of cell-associated un-spliced HIV-1 RNA increased significantly from baseline during treatment (range of fold-increase: 2.4–5.0; p = 0.03. Plasma HIV-1 RNA increased from <20 copies/mL at baseline to readily quantifiable levels at multiple post-infusion time-points in 5 of 6 patients (range 46–103 copies/mL following the second infusion, p = 0.04. Importantly, romidepsin did not decrease the number of HIV-specific T cells or inhibit T cell cytokine production. Adverse events (all grade 1–2 were consistent with the known side effects of romidepsin. In conclusion, romidepsin safely induced HIV-1 transcription resulting in plasma HIV-1 RNA that was readily detected with standard commercial assays demonstrating that significant reversal of HIV-1 latency in vivo is possible without blunting T cell-mediated immune responses. These finding have major implications for future trials aiming to eradicate the HIV-1 reservoir.clinicaltrials.gov NTC02092116.

  12. Sexually transmitted infections among HIV-1-discordant couples.

    Directory of Open Access Journals (Sweden)

    Brandon L Guthrie

    Full Text Available INTRODUCTION: More new HIV-1 infections occur within stable HIV-1-discordant couples than in any other group in Africa, and sexually transmitted infections (STIs may increase transmission risk among discordant couples, accounting for a large proportion of new HIV-1 infections. Understanding correlates of STIs among discordant couples will aid in optimizing interventions to prevent HIV-1 transmission in these couples. METHODS: HIV-1-discordant couples in which HIV-1-infected partners were HSV-2-seropositive were tested for syphilis, chlamydia, gonorrhea, and trichomoniasis, and HIV-1-uninfected partners were tested for HSV-2. We assessed sociodemographic, behavioral, and biological correlates of a current STI. RESULTS: Of 416 couples enrolled, 16% were affected by a treatable STI, and among these both partners were infected in 17% of couples. A treatable STI was found in 46 (11% females and 30 (7% males. The most prevalent infections were trichomoniasis (5.9% and syphilis (2.6%. Participants were 5.9-fold more likely to have an STI if their partner had an STI (P<0.01, and STIs were more common among those reporting any unprotected sex (OR = 2.43; P<0.01 and those with low education (OR = 3.00; P<0.01. Among HIV-1-uninfected participants with an HSV-2-seropositive partner, females were significantly more likely to be HSV-2-seropositive than males (78% versus 50%, P<0.01. CONCLUSIONS: Treatable STIs were common among HIV-1-discordant couples and the majority of couples affected by an STI were discordant for the STI, with relatively high HSV-2 discordance. Awareness of STI correlates and treatment of both partners may reduce HIV-1 transmission. TRIAL REGISTRATION: ClinicalTrials.gov NCT00194519.

  13. HIV-1 activates macrophages independent of Toll-like receptors.

    Directory of Open Access Journals (Sweden)

    Joseph N Brown

    Full Text Available BACKGROUND: Macrophages provide an interface between innate and adaptive immunity and are important long-lived reservoirs for Human Immunodeficiency Virus Type-1 (HIV-1. Multiple genetic networks involved in regulating signal transduction cascades and immune responses in macrophages are coordinately modulated by HIV-1 infection. METHODOLOGY/PRINCIPAL FINDINGS: To evaluate complex interrelated processes and to assemble an integrated view of activated signaling networks, a systems biology strategy was applied to genomic and proteomic responses by primary human macrophages over the course of HIV-1 infection. Macrophage responses, including cell cycle, calcium, apoptosis, mitogen-activated protein kinases (MAPK, and cytokines/chemokines, to HIV-1 were temporally regulated, in the absence of cell proliferation. In contrast, Toll-like receptor (TLR pathways remained unaltered by HIV-1, although TLRs 3, 4, 7, and 8 were expressed and responded to ligand stimulation in macrophages. HIV-1 failed to activate phosphorylation of IRAK-1 or IRF-3, modulate intracellular protein levels of Mx1, an interferon-stimulated gene, or stimulate secretion of TNF, IL-1beta, or IL-6. Activation of pathways other than TLR was inadequate to stimulate, via cross-talk mechanisms through molecular hubs, the production of proinflammatory cytokines typical of a TLR response. HIV-1 sensitized macrophage responses to TLR ligands, and the magnitude of viral priming was related to virus replication. CONCLUSIONS/SIGNIFICANCE: HIV-1 induced a primed, proinflammatory state, M1(HIV, which increased the responsiveness of macrophages to TLR ligands. HIV-1 might passively evade pattern recognition, actively inhibit or suppress recognition and signaling, or require dynamic interactions between macrophages and other cells, such as lymphocytes or endothelial cells. HIV-1 evasion of TLR recognition and simultaneous priming of macrophages may represent a strategy for viral survival, contribute

  14. Molecular mechanisms of HIV-1 associated neurodegeneration

    Indian Academy of Sciences (India)

    Hakan Ozdener

    2005-06-01

    Since identification of the human immunodeficiency virus-1 (HIV-1), numerous studies suggest a link between neurological impairments, in particular dementia, with acquired immunodeficiency syndrome (AIDS) with alarming occurrence worldwide. Approximately, 60% of HIV-infected people show some form of neurological impairment, and neuropathological changes are found in 90% of autopsied cases. Approximately 30% of untreated HIV-infected persons may develop dementia. The mechanisms behind these pathological changes are still not understood. Mounting data obtained by in vivo and in vitro experiments suggest that neuronal apoptosis is a major feature of HIV associated dementia (HAD), which can occur in the absence of direct infection of neurons. The major pathway of neuronal apoptosis occurs indirectly through release of neurotoxins by activated cells in the central nervous system (CNS) involving the induction of excitotoxicity and oxidative stress. In addition a direct mechanism induced by viral proteins in the pathogenesis of HAD may also play a role. This review focuses on the molecular mechanisms of HIV-associated dementia and possible therapeutic strategies.

  15. Cell signaling pathways and HIV-1 therapeutics.

    Science.gov (United States)

    He, Johnny J

    2011-06-01

    Host-virus interactions permeate every aspect of both virus life cycle and host response and involve host cell macromolecular machinery and viral elements. It is these intimate interactions that mandate the outcomes of the infection and pathogenesis. It is also these intimate interactions that lay the foundation for the development of pharmaceutical interventions. HIV-1 is no exception in these regards. In the first two decades, HIV/AIDS research has led to the successful development of a number of antiviral inhibitors and the landmark formulation of the suppressive therapy. It has become apparent that this therapy does not offer a complete solution to cure and eradicate the virus. Meanwhile, this therapy has changed the overall landscape of HIV-associated neurological disorders to a more common and prevalent form so-called minor cognitive motor disorder. Thus, there is an important and continued need for new anti-HIV therapeutics. We believe that this is an excellent opportunity to compile and present the latest works being done during the last few years in this exciting field of HIV-host interactions, particularly cell signaling pathways. We hope that this special issue composed of one brief report, eight thematic reviews, and two original articles will serve to foster the exchange of new scientific ideas on HIV-host interactions and anti-HIV therapy and eventually contribute to HIV/AIDS eradication.

  16. HIV-1 molecular epidemiology among newly diagnosed HIV-1 individuals in Hebei, a low HIV prevalence province in China

    Science.gov (United States)

    Lu, Xinli; Kang, Xianjiang; Liu, Yongjian; Cui, Ze; Guo, Wei; Zhao, Cuiying; Li, Yan; Chen, Suliang; Li, Jingyun; Zhang, Yuqi; Zhao, Hongru

    2017-01-01

    New human immunodeficiency virus type 1 (HIV-1) diagnoses are increasing rapidly in Hebei. The aim of this study presents the most extensive HIV-1 molecular epidemiology investigation in Hebei province in China thus far. We have carried out the most extensive systematic cross-sectional study based on newly diagnosed HIV-1 positive individuals in 2013, and characterized the molecular epidemiology of HIV-1 based on full length gag-partial pol gene sequences in the whole of Hebei. Nine HIV-1 genotypes based on full length gag-partial pol gene sequence were identified among 610 newly diagnosed naïve individuals. The four main genotypes were circulating recombinant form (CRF)01_AE (53.4%), CRF07_BC (23.4%), subtype B (15.9%), and unique recombinant forms URFs (4.9%). Within 1 year, three new genotypes (subtype A1, CRF55_01B, CRF65_cpx), unknown before in Hebei, were first found among men who have sex with men (MSM). All nine genotypes were identified in the sexually contracted HIV-1 population. Among 30 URFs, six recombinant patterns were revealed, including CRF01_AE/BC (40.0%), CRF01_AE/B (23.3%), B/C (16.7%), CRF01_AE/C (13.3%), CRF01_AE/B/A2 (3.3%) and CRF01_AE/BC/A2 (3.3%), plus two potential CRFs. This study elucidated the complicated characteristics of HIV-1 molecular epidemiology in a low HIV-1 prevalence northern province of China and revealed the high level of HIV-1 genetic diversity. All nine HIV-1 genotypes circulating in Hebei have spread out of their initial risk groups into the general population through sexual contact, especially through MSM. This highlights the urgency of HIV prevention and control in China. PMID:28178737

  17. Anti-HIV-1 activity of flavonoid myricetin on HIV-1 infection in a dual-chamber in vitro model.

    Directory of Open Access Journals (Sweden)

    Silvana Pasetto

    Full Text Available HIV infection by sexual transmission remains an enormous global health concern. More than 1 million new infections among women occur annually. Microbicides represent a promising prevention strategy that women can easily control. Among emerging therapies, natural small molecules such as flavonoids are an important source of new active substances. In this study we report the in vitro cytotoxicity and anti-HIV-1 and microbicide activity of the following flavonoids: Myricetin, Quercetin and Pinocembrin. Cytotoxicity tests were conducted on TZM-bl, HeLa, PBMC, and H9 cell cultures using 0.01-100 µM concentrations. Myricetin presented the lowest toxic effect, with Quercetin and Pinocembrin relatively more toxic. The anti-HIV-1 activity was tested with TZM-bl cell plus HIV-1 BaL (R5 tropic, H9 and PBMC cells plus HIV-1 MN (X4 tropic, and the dual tropic (X4R5 HIV-1 89.6. All flavonoids showed anti-HIV activity, although Myricetin was more effective than Quercetin or Pinocembrin. In TZM-bl cells, Myricetin inhibited ≥90% of HIV-1 BaL infection. The results were confirmed by quantification of HIV-1 p24 antigen in supernatant from H9 and PBMC cells following flavonoid treatment. In H9 and PBMC cells infected by HIV-1 MN and HIV-1 89.6, Myricetin showed more than 80% anti-HIV activity. Quercetin and Pinocembrin presented modest anti-HIV activity in all experiments. Myricetin activity was tested against HIV-RT and inhibited the enzyme by 49%. Microbicide activities were evaluated using a dual-chamber female genital tract model. In the in vitro microbicide activity model, Myricetin showed promising results against different strains of HIV-1 while also showing insignificant cytotoxic effects. Further studies of Myricetin should be performed to identify its molecular targets in order to provide a solid biological foundation for translational research.

  18. HIV-1 Vif adaptation to human APOBEC3H haplotypes.

    Science.gov (United States)

    Ooms, Marcel; Brayton, Bonnie; Letko, Michael; Maio, Susan M; Pilcher, Christopher D; Hecht, Frederick M; Barbour, Jason D; Simon, Viviana

    2013-10-16

    Several human APOBEC3 deaminases can inhibit HIV-1 replication in vitro. HIV-1 Vif counteracts this restriction by targeting APOBEC3 for proteasomal degradation. Human APOBEC3H (A3H) is highly polymorphic, with natural variants differing considerably in anti-HIV-1 activity in vitro. To examine HIV-1 adaptation to variation in A3H activity in a natural infection context, we determined the A3H haplotypes and Vif sequences from 76 recently infected HIV-1 patients. We detected A3H-specific Vif changes suggesting viral adaptation. The patient-derived Vif sequences were used to engineer viruses that specifically differed in their ability to counteract A3H. Replication of these Vif-variant viruses in primary T cells naturally expressing active or inactive A3H haplotypes showed that endogenously expressed A3H restricts HIV-1 replication. Proviral DNA from A3H-restricted viruses showed high levels of G-to-A mutations in an A3H-specific GA dinucleotide context. Taken together, our data validate A3H expressed at endogenous levels as a bona fide HIV-1 restriction factor.

  19. Correlates of HIV-1 genital shedding in Tanzanian women.

    Directory of Open Access Journals (Sweden)

    Clare Tanton

    Full Text Available BACKGROUND: Understanding the correlates of HIV shedding is important to inform strategies to reduce HIV infectiousness. We examined correlates of genital HIV-1 RNA in women who were seropositive for both herpes simplex virus (HSV-2 and HIV-1 and who were enrolled in a randomised controlled trial of HSV suppressive therapy (aciclovir 400 mg b.i.d vs. placebo in Tanzania. METHODOLOGY: Samples, including a cervico-vaginal lavage, were collected and tested for genital HIV-1 and HSV and reproductive tract infections (RTIs at randomisation and 6, 12 and 24 months follow-up. Data from all women at randomisation and women in the placebo arm during follow-up were analysed using generalised estimating equations to determine the correlates of cervico-vaginal HIV-1 RNA detection and load. PRINCIPAL FINDINGS: Cervico-vaginal HIV-1 RNA was detected at 52.0% of 971 visits among 482 women, and was independently associated with plasma viral load, presence of genital ulcers, pregnancy, bloody cervical or vaginal discharge, abnormal vaginal discharge, cervical ectopy, Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, an intermediate bacterial vaginosis score and HSV DNA detection. Similar factors were associated with genital HIV-1 RNA load. CONCLUSIONS: RTIs were associated with increased presence and quantity of genital HIV-1 RNA in this population. These results highlight the importance of integrating effective RTI treatment into HIV care services.

  20. Defining the roles for Vpr in HIV-1-associated neuropathogenesis.

    Science.gov (United States)

    James, Tony; Nonnemacher, Michael R; Wigdahl, Brian; Krebs, Fred C

    2016-08-01

    It is increasingly evident that the human immunodeficiency virus type 1 (HIV-1) viral protein R (Vpr) has a unique role in neuropathogenesis. Its ability to induce G2/M arrest coupled with its capacity to increase viral gene transcription gives it a unique role in sustaining viral replication and aiding in the establishment and maintenance of a systemic infection. The requirement of Vpr for HIV-1 infection and replication in cells of monocytic origin (a key lineage of cells involved in HIV-1 neuroinvasion) suggests an important role in establishing and sustaining infection in the central nervous system (CNS). Contributions of Vpr to neuropathogenesis can be expanded further through (i) naturally occurring HIV-1 sequence variation that results in functionally divergent Vpr variants; (ii) the dual activities of Vpr as a intracellular protein delivered and expressed during HIV-1 infection and as an extracellular protein that can act on neighboring, uninfected cells; (iii) cell type-dependent consequences of Vpr expression and exposure, including cell cycle arrest, metabolic dysregulation, and cytotoxicity; and (iv) the effects of Vpr on exosome-based intercellular communication in the CNS. Revealing that the effects of this pleiotropic viral protein is an essential part of a greater understanding of HIV-1-associated pathogenesis and potential approaches to treating and preventing disease caused by HIV-1 infection.

  1. Immunogenicity of a recombinant measles HIV-1 subtype C vaccine.

    Science.gov (United States)

    Stebbings, Richard; Li, Bo; Lorin, Clarisse; Koutsoukos, Marguerite; Février, Michèle; Mee, Edward T; Page, Mark; Almond, Neil; Tangy, Frédéric; Voss, Gérald

    2013-12-09

    The HIV epidemic is greatest in Sub-Saharan Africa and India where HIV-1 subtype C is predominant. To control the spread of HIV in these parts of the world a preventive HIV-1 subtype C vaccine is urgently required. Here we report the immunogenicity of a candidate HIV-1 subtype C vaccine delivered by a recombinant measles vector carrying an insert encoding HIV-1 subtype C Gag, RT and Nef (MV1-F4), in MHC-typed non-human primates. HIV-1 specific cytokine secreting CD4+ and CD8+ T cell responses were detected in 15 out of 16 vaccinees. These HIV-specific T cell responses persisted in lymphoid tissues. Anti-HIV-1 antibody responses were detected in 15 out of 16 vaccinees and titres were boosted by a second immunisation carried out 84 days later. These findings support further exploration of the MV1-F4 vector as a candidate HIV-1 subtype C vaccine or as part of a wider vaccine strategy.

  2. Candidate antibody-based therapeutics against HIV-1.

    Science.gov (United States)

    Gong, Rui; Chen, Weizao; Dimitrov, Dimiter S

    2012-06-01

    Antibody-based therapeutics have been successfully used for the treatment of various diseases and as research tools. Several well characterized, broadly neutralizing monoclonal antibodies (bnmAbs) targeting HIV-1 envelope glycoproteins or related host cell surface proteins show sterilizing protection of animals, but they are not effective when used for therapy of an established infection in humans. Recently, a number of novel bnmAbs, engineered antibody domains (eAds), and multifunctional fusion proteins have been reported which exhibit exceptionally potent and broad neutralizing activity against a wide range of HIV-1 isolates from diverse genetic subtypes. eAds could be more effective in vivo than conventional full-size antibodies generated by the human immune system. Because of their small size (12∼15 kD), they can better access sterically restricted epitopes and penetrate densely packed tissue where HIV-1 replicates than the larger full-size antibodies. HIV-1 possesses a number of mechanisms to escape neutralization by full-size antibodies but could be less likely to develop resistance to eAds. Here, we review the in vitro and in vivo antiviral efficacies of existing HIV-1 bnmAbs, summarize the development of eAds and multispecific fusion proteins as novel types of HIV-1 inhibitors, and discuss possible strategies to generate more potent antibody-based candidate therapeutics against HIV-1, including some that could be used to eradicate the virus.

  3. HIV-1 envelope glycoprotein immunogens to induce broadly neutralizing antibodies.

    Science.gov (United States)

    Sliepen, Kwinten; Sanders, Rogier W

    2016-01-01

    The long pursuit for a vaccine against human immunodeficiency virus 1 (HIV-1) has recently been boosted by a number of exciting developments. An HIV-1 subunit vaccine ideally should elicit potent broadly neutralizing antibodies (bNAbs), but raising bNAbs by vaccination has proved extremely difficult because of the characteristics of the HIV-1 envelope glycoprotein complex (Env). However, the isolation of bNAbs from HIV-1-infected patients demonstrates that the human humoral immune system is capable of making such antibodies. Therefore, a focus of HIV-1 vaccinology is the elicitation of bNAbs by engineered immunogens and by using vaccination strategies aimed at mimicking the bNAb maturation pathways in HIV-infected patients. Important clues can also be taken from the successful subunit vaccines against hepatitis B virus and human papillomavirus. Here, we review the different types of HIV-1 immunogens and vaccination strategies that are being explored in the search for an HIV-1 vaccine that induces bNAbs.

  4. Efficient Gene Transfer Mediated by HIV-1-based Defective Lentivector and Inhibition of HIV-1 Replication

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Lentiviral vectors have drawn considerable attention recently and show great promise to become important delivery vehicles for future gene transfer manipulation. In the present study we have optimized a protocol for preparation of human immunodeficiency virus type-1 (HIV-1)-based defective lentiviral vectors (DLV) and characterized these vectors in terms of their transduction of different cells. Transient co-transfection of 293T packaging cells with DNA plasmids encoding lentiviral vector constituents resulted in production of high-titer DLV (0.5-1.2 × 107IU/mL), which can be further concentrated over 100-fold through a single step ultracentrifugation. These vectors were capable of transducing a variety of cells from both primate and non-primate sources and high transduction efficiency was achieved using concentrated vectors. Assessment of potential generation of RCV revealed no detection of infection by infectious particles in DLV-transduced CEM, SupT-1 and MT-2 cells. Long-term culture of transduced cells showed a stable expression of transgenes without apparent alteration in cellular morphology and growth kinetics. Vector mobilization to untransduced cells mediated by wild-type HIV-1 infection was confirmed in this test. Challenge of transduced human T-lymphocytes with wild-type HIV-1 showed these cells are totally resistant to the viral infection. Considering the effective gene transfer and stable gene expression, safety and anti-HIV activity, these DLV vectors warrant further exploration for their potential use as a gene transfer vehicle in the development of gene therapy protocols.

  5. RNA interference and HIV-1%RNA干扰和HIV-1

    Institute of Scientific and Technical Information of China (English)

    陈彬; 杨磊; 谭晓华

    2010-01-01

    RNA干扰(RNA interference,RNAi)是指由短双链RNA诱导的同源RNA降解过程或者是指诱导DNA甲基化的方式对其同源序列的基因表达进行干涉的过程.传统观念认为,这种现象发生在转录后水平又称为转录后基因沉默(post-transcriptional gene silence,PTGS).然而,最近研究表明,干扰小RNA(small interfering RNA,siRNA)是一些甲基化转移酶活化的起始信号,能在转录水平调控(沉默)基因的表达(transcriptional gene silence,TGS).该机制广泛存在于从酵母到哺乳动物的细胞中,能调节多种生物学的过程.新近的研究表明细胞和病毒miRNA(vmiRNA)都能调节病毒的复制;还有研究表明有些病毒,比如HIV-1,可以直接调控细胞内的RNA干扰的能力.RNA干扰有可能成为一种新的防治HIV-1感染的基因治疗方法,本文就RNA干扰作用机制以及在HIV-1感染方面的应用进行综述.

  6. Genome editing strategies: potential tools for eradicating HIV-1/AIDS.

    Science.gov (United States)

    Khalili, Kamel; Kaminski, Rafal; Gordon, Jennifer; Cosentino, Laura; Hu, Wenhui

    2015-06-01

    Current therapy for controlling human immunodeficiency virus (HIV-1) infection and preventing acquired immunodeficiency syndrome (AIDS) progression has profoundly decreased viral replication in cells susceptible to HIV-1 infection, but it does not eliminate the low level of viral replication in latently infected cells, which contain integrated copies of HIV-1 proviral DNA. There is an urgent need for the development of HIV-1 genome eradication strategies that will lead to a permanent or "sterile" cure of HIV-1/AIDS. In the past few years, novel nuclease-initiated genome editing tools have been developing rapidly, including zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and the CRISPR/Cas9 system. These surgical knives, which can excise any genome, provide a great opportunity to eradicate the HIV-1 genome by targeting highly conserved regions of the HIV-1 long terminal repeats or essential viral genes. Given the time consuming and costly engineering of target-specific ZFNs and TALENs, the RNA-guided endonuclease Cas9 technology has emerged as a simpler and more versatile technology to allow permanent removal of integrated HIV-1 proviral DNA in eukaryotic cells, and hopefully animal models or human patients. The major unmet challenges of this approach at present include inefficient nuclease gene delivery, potential off-target cleavage, and cell-specific genome targeting. Nanoparticle or lentivirus-mediated delivery of next generation Cas9 technologies including nickase or RNA-guided FokI nuclease (RFN) will further improve the potential for genome editing to become a promising approach for curing HIV-1/AIDS.

  7. HIV-1/HSV-2 co-infected adults in early HIV-1 infection have elevated CD4+ T cell counts.

    Directory of Open Access Journals (Sweden)

    Jason D Barbour

    Full Text Available INTRODUCTION: HIV-1 is often acquired in the presence of pre-existing co-infections, such as Herpes Simplex Virus 2 (HSV-2. We examined the impact of HSV-2 status at the time of HIV-1 acquisition for its impact on subsequent clinical course, and total CD4+ T cell phenotypes. METHODS: We assessed the relationship of HSV-1/HSV-2 co-infection status on CD4+ T cell counts and HIV-1 RNA levels over time prior in a cohort of 186 treatment naïve adults identified during early HIV-1 infection. We assessed the activation and differentiation state of total CD4+ T cells at study entry by HSV-2 status. RESULTS: Of 186 recently HIV-1 infected persons, 101 (54% were sero-positive for HSV-2. There was no difference in initial CD8+ T cell count, or differences between the groups for age, gender, or race based on HSV-2 status. Persons with HIV-1/HSV-2 co-infection sustained higher CD4+ T cell counts over time (+69 cells/ul greater (SD = 33.7, p = 0.04 than those with HIV-1 infection alone (Figure 1, after adjustment for HIV-1 RNA levels (-57 cells per 1 log(10 higher HIV-1 RNA, p<0.0001. We did not observe a relationship between HSV-2 infection status with plasma HIV-1 RNA levels over time. HSV-2 acquisition after HIV-1 acquisition had no impact on CD4+ count or viral load. We did not detect differences in CD4+ T cell activation or differentiation state by HSV-2+ status. DISCUSSION: We observed no effect of HSV-2 status on viral load. However, we did observe that treatment naïve, recently HIV-1 infected adults co-infected with HSV-2+ at the time of HIV-1 acquisition had higher CD4+ T cell counts over time. If verified in other cohorts, this result poses a striking paradox, and its public health implications are not immediately clear.

  8. HIV-1 Replication and the Cellular Eukaryotic Translation Apparatus

    Directory of Open Access Journals (Sweden)

    Santiago Guerrero

    2015-01-01

    Full Text Available Eukaryotic translation is a complex process composed of three main steps: initiation, elongation, and termination. During infections by RNA- and DNA-viruses, the eukaryotic translation machinery is used to assure optimal viral protein synthesis. Human immunodeficiency virus type I (HIV-1 uses several non-canonical pathways to translate its own proteins, such as leaky scanning, frameshifting, shunt, and cap-independent mechanisms. Moreover, HIV-1 modulates the host translation machinery by targeting key translation factors and overcomes different cellular obstacles that affect protein translation. In this review, we describe how HIV-1 proteins target several components of the eukaryotic translation machinery, which consequently improves viral translation and replication.

  9. Ex vivo gene therapy for HIV-1 treatment.

    Science.gov (United States)

    Scherer, Lisa J; Rossi, John J

    2011-04-15

    Until recently, progress in ex vivo gene therapy (GT) for human immunodeficiency virus-1 (HIV-1) treatment has been incremental. Long-term HIV-1 remission in a patient who received a heterologous stem cell transplant for acquired immunodeficiency syndrome-related lymphoma from a CCR5(-/-) donor, even after discontinuation of conventional therapy, has energized the field. We review the status of current approaches as well as future directions in the areas of therapeutic targets, combinatorial strategies, vector design, introduction of therapeutics into stem cells and enrichment/expansion of gene-modified cells. Finally, we discuss recent advances towards clinical application of HIV-1 GT.

  10. Vpr Promotes Macrophage-Dependent HIV-1 Infection of CD4+ T Lymphocytes.

    Directory of Open Access Journals (Sweden)

    David R Collins

    2015-07-01

    Full Text Available Vpr is a conserved primate lentiviral protein that promotes infection of T lymphocytes in vivo by an unknown mechanism. Here we demonstrate that Vpr and its cellular co-factor, DCAF1, are necessary for efficient cell-to-cell spread of HIV-1 from macrophages to CD4+ T lymphocytes when there is inadequate cell-free virus to support direct T lymphocyte infection. Remarkably, Vpr functioned to counteract a macrophage-specific intrinsic antiviral pathway that targeted Env-containing virions to LAMP1+ lysosomal compartments. This restriction of Env also impaired virological synapses formed through interactions between HIV-1 Env on infected macrophages and CD4 on T lymphocytes. Treatment of infected macrophages with exogenous interferon-alpha induced virion degradation and blocked synapse formation, overcoming the effects of Vpr. These results provide a mechanism that helps explain the in vivo requirement for Vpr and suggests that a macrophage-dependent stage of HIV-1 infection drives the evolutionary conservation of Vpr.

  11. HIV-1 Tat RNA silencing suppressor activity is conserved across kingdoms and counteracts translational repression of HIV-1.

    Science.gov (United States)

    Qian, Shuiming; Zhong, Xuehua; Yu, Lianbo; Ding, Biao; de Haan, Peter; Boris-Lawrie, Kathleen

    2009-01-13

    The RNA silencing pathway is an intracellular innate response to virus infections and retro-transposons. Many plant viruses counter this host restriction by RNA silencing suppressor (RSS) activity of a double-stranded RNA-binding protein, e.g., tomato bushy stunt virus P19. Here, we demonstrate P19 and HIV-1 Tat function across the plant and animal kingdoms and suppress a common step in RNA silencing that is downstream of small RNA maturation. Our experiments reveal that RNA silencing in HIV-1 infected human cells severely attenuates the translational output of the unspliced HIV-1 gag mRNA, and possibly all HIV-1 transcripts. The attenuation in gag mRNA translation is exacerbated by K51A substitution in the Tat double-stranded RNA-binding domain. Tat, plant virus RSS, or Dicer downregulation rescues robust gag translation and bolsters HIV-1 virion production. The reversal of HIV-1 translation repression by plant RSS supports the recent finding in Arabidopsis that plant miRNAs operate by translational inhibition. Our results identify common features between RNA silencing suppression of plant and animal viruses. We suggest that RNA silencing-mediated translation repression plays a strategic role in determining the viral set-point in a newly HIV-1-infected patient.

  12. Achieving HIV-1 Control through RNA-Directed Gene Regulation

    Directory of Open Access Journals (Sweden)

    Vera Klemm

    2016-12-01

    Full Text Available HIV-1 infection has been transformed by combined anti-retroviral therapy (ART, changing a universally fatal infection into a controllable infection. However, major obstacles for an HIV-1 cure exist. The HIV latent reservoir, which exists in resting CD4+ T cells, is not impacted by ART, and can reactivate when ART is interrupted or ceased. Additionally, multi-drug resistance can arise. One alternate approach to conventional HIV-1 drug treatment that is being explored involves gene therapies utilizing RNA-directed gene regulation. Commonly known as RNA interference (RNAi, short interfering RNA (siRNA induce gene silencing in conserved biological pathways, which require a high degree of sequence specificity. This review will provide an overview of the silencing pathways, the current RNAi technologies being developed for HIV-1 gene therapy, current clinical trials, and the challenges faced in progressing these treatments into clinical trials.

  13. Purinergic Receptors: Key Mediators of HIV-1 infection and inflammation

    Directory of Open Access Journals (Sweden)

    Talia H Swartz

    2015-11-01

    Full Text Available Human immunodeficiency virus (HIV-1 causes a chronic infection that afflicts more than 38 million individuals worldwide. While the infection can be suppressed with potent anti-retroviral therapies, individuals infected with HIV have elevated levels of inflammation as indicated by increased T cell activation, soluble biomarkers, and associated morbidity and mortality. A single mechanism linking HIV pathogenesis to this inflammation has yet to be identified. Purinergic receptors are known to mediate inflammation and have been shown to be required for HIV-1 infection at the level of HIV-1 membrane fusion. Here we review the literature on the role of purinergic receptors in HIV-1 infection and associated inflammation and describe a role for these receptors as potential therapeutic targets.

  14. Early Combination Antiretroviral Therapy Limits HIV-1 Persistence in Children.

    Science.gov (United States)

    Luzuriaga, Katherine

    2016-01-01

    Globally, 240,000 infants are newly infected with HIV-1 each year and 3.2 million children are living with the infection. Combination antiretroviral therapy (cART) has reduced HIV-1-related disease and mortality in children but is not curative owing to the early generation of a latent reservoir of long-lived memory CD4(+) T cells bearing replication-competent HIV-1 provirus integrated into cellular DNA. This review focuses on recent advances in our understanding of the establishment of HIV-1 persistence in children and how early initiation of cART in the setting of the developing infant immune system limits the formation of the long-lived latent CD4(+) cell reservoir that remains a barrier to remission or cure.

  15. Lipids and Membrane Microdomains in HIV-1 Replication

    OpenAIRE

    Waheed, Abdul A.; Freed, Eric O.

    2009-01-01

    Several critical steps in the replication cycle of human immunodeficiency virus type 1 (HIV-1) – entry, assembly and budding – are complex processes that take place at the plasma membrane of the host cell. A growing body of data indicates that these early and late steps in HIV-1 replication take place in specialized plasma membrane microdomains, and that many of the viral and cellular components required for entry, assembly, and budding are concentrated in these microdomains. In particular, a...

  16. Innate Immune Activation in Primary HIV-1 Infection

    OpenAIRE

    Chang, J. Judy; Altfeld, Marcus

    2010-01-01

    There is growing evidence highlighting the role of the immune response during acute HIV-1 infection on the control or development of disease. The adaptive immune responses do not appear until after the HIV-1 infection is already well established and as such the role of the earlier and faster responding innate immunity needs to be more closely scrutinized. In particular, two aspects of the innate immunity with growing developments will be examined in this review; type I IFNs and NK cells. Both...

  17. Sensitive non-radioactive detection of HIV-1

    DEFF Research Database (Denmark)

    Teglbjærg, Lars Stubbe; Nielsen, C; Hansen, J E

    1992-01-01

    This report describes the use of the polymerase chain reaction (PCR) for the non-radioactive detection of HIV-1 proviral genomic sequences in HIV-1 infected cells. We have developed a sensitive assay, using three different sets of nested primers and our results show that this method is superior t...... genomic copies often are present at such low numbers that they are otherwise undetectable....

  18. HLA-C Downmodulation by HIV-1 Vpu.

    Science.gov (United States)

    Barker, Edward; Evans, David T

    2016-05-11

    It is widely held that HIV-1 Nef downmodulates HLA-A and -B to protect infected cells from CD8(+) T cells but leaves HLA-C on the cell surface to inhibit NK cells. In this issue of Cell Host & Microbe, Apps et al. (2016) revise this model by showing that the Vpu protein of primary HIV-1 isolates downmodulate HLA-C.

  19. Impairment of B-cell functions during HIV-1 infection.

    Science.gov (United States)

    Amu, Sylvie; Ruffin, Nicolas; Rethi, Bence; Chiodi, Francesca

    2013-09-24

    A variety of B-cell dysfunctions are manifested during HIV-1 infection, as reported early during the HIV-1 epidemic. It is not unusual that the pathogenic mechanisms presented to elucidate impairment of B-cell responses during HIV-1 infection focus on the impact of reduced T-cell numbers and functions, and lack of germinal center formation in lymphoid tissues. To our understanding, however, perturbation of B-cell phenotype and function during HIV-1 infection may begin at several different B-cell developmental stages. These impairments can be mediated by intrinsic B-cell defects as well as by the lack of proper T-cell help. In this review, we will highlight some of the pathways and molecular interactions leading to B-cell impairment prior to germinal center formation and B-cell activation mediated through the B-cell receptor in response to HIV-1 antigens. Recent studies indicate a regulatory role for B cells on T-cell biology and immune responses. We will discuss some of these novel findings and how these regulatory mechanisms could potentially be affected by the intrinsic defects of B cells taking place during HIV-1 infection.

  20. Potent inhibition of HIV-1 replication by a Tat mutant.

    Science.gov (United States)

    Meredith, Luke W; Sivakumaran, Haran; Major, Lee; Suhrbier, Andreas; Harrich, David

    2009-11-10

    Herein we describe a mutant of the two-exon HIV-1 Tat protein, termed Nullbasic, that potently inhibits multiple steps of the HIV-1 replication cycle. Nullbasic was created by replacing the entire arginine-rich basic domain of wild type Tat with glycine/alanine residues. Like similarly mutated one-exon Tat mutants, Nullbasic exhibited transdominant negative effects on Tat-dependent transactivation. However, unlike previously reported mutants, we discovered that Nullbasic also strongly suppressed the expression of unspliced and singly-spliced viral mRNA, an activity likely caused by redistribution and thus functional inhibition of HIV-1 Rev. Furthermore, HIV-1 virion particles produced by cells expressing Nullbasic had severely reduced infectivity, a defect attributable to a reduced ability of the virions to undergo reverse transcription. Combination of these inhibitory effects on transactivation, Rev-dependent mRNA transport and reverse transcription meant that permissive cells constitutively expressing Nullbasic were highly resistant to a spreading infection by HIV-1. Nullbasic and its activities thus provide potential insights into the development of potent antiviral therapeutics that target multiple stages of HIV-1 infection.

  1. Potent inhibition of HIV-1 replication by a Tat mutant.

    Directory of Open Access Journals (Sweden)

    Luke W Meredith

    Full Text Available Herein we describe a mutant of the two-exon HIV-1 Tat protein, termed Nullbasic, that potently inhibits multiple steps of the HIV-1 replication cycle. Nullbasic was created by replacing the entire arginine-rich basic domain of wild type Tat with glycine/alanine residues. Like similarly mutated one-exon Tat mutants, Nullbasic exhibited transdominant negative effects on Tat-dependent transactivation. However, unlike previously reported mutants, we discovered that Nullbasic also strongly suppressed the expression of unspliced and singly-spliced viral mRNA, an activity likely caused by redistribution and thus functional inhibition of HIV-1 Rev. Furthermore, HIV-1 virion particles produced by cells expressing Nullbasic had severely reduced infectivity, a defect attributable to a reduced ability of the virions to undergo reverse transcription. Combination of these inhibitory effects on transactivation, Rev-dependent mRNA transport and reverse transcription meant that permissive cells constitutively expressing Nullbasic were highly resistant to a spreading infection by HIV-1. Nullbasic and its activities thus provide potential insights into the development of potent antiviral therapeutics that target multiple stages of HIV-1 infection.

  2. HIV-1, Methamphetamine and Astrocytes at Neuroinflammatory crossroads

    Directory of Open Access Journals (Sweden)

    Kathleen eBorgmann

    2015-10-01

    Full Text Available As a popular psychostimulant, methamphetamine (METH use leads to long-lasting, strong euphoric effects. While METH abuse is common in the general population, between 10-15% of human immunodeficiency virus-1 (HIV-1 patients report having abused METH. METH exacerbates the severity and onset of HIV-1-associated neurocognitive disorders (HAND through direct and indirect mechanisms. Repetitive METH use decreases adherence to antiretroviral drug regimens, increasing the likelihood of HIV-1 disease progression towards AIDS. METH exposure also directly affects both innate and adaptive immunity, altering lymphocyte number and activity, cytokine signaling, phagocytic function, and CNS infiltration through the blood brain barrier. Further, METH triggers the neuronal dopamine reward pathway and leads to altered neuronal activity and direct toxicity. Concurrently, METH and HIV-1 alter the neuroimmune balance and induce neuroinflammation. Neuroinflammation modulates a wide range of brain functions including neuronal signaling and activity, glial activation, viral infection, oxidative stress and excitotoxicity. Pathologically, glial activation is a hallmark of both HIV-1 and METH-associated neuroinflammation. Significant commonality exists in the neurotoxic mechanisms for both METH and HAND; however, the pathways dysregulated in astroglia during METH exposure are less clear. Thus alterations in astrocyte intracellular signaling pathways, gene expression and function during METH and HIV-1 comorbidity, neuroinflammation and HAND are carefully reviewed. Interventions targeting astrocytes in HAND and METH are presented as potential novel therapeutic approaches.

  3. Viral piracy: HIV-1 targets dendritic cells for transmission.

    Science.gov (United States)

    Lekkerkerker, Annemarie N; van Kooyk, Yvette; Geijtenbeek, Teunis B H

    2006-04-01

    Dendritic cells (DCs), the professional antigen presenting cells, are critical for host immunity by inducing specific immune responses against a broad variety of pathogens. Remarkably the human immunodeficiency virus-1 (HIV-1) subverts DC function leading to spread of the virus. At an early phase of HIV-1 transmission, DCs capture HIV-1 at mucosal surfaces and transmit the virus to T cells in secondary lymphoid tissues. Capture of the virus on DCs takes place via C-type lectins of which the dendritic cell-specific intercellular adhesion molecule-3 (ICAM-3) grabbing nonintegrin (DC-SIGN) is the best studied. DC-SIGN-captured HIV-1 particles accumulate in CD81(+) multivesicular bodies (MVBs) in DCs and are subsequently transmitted to CD4+ T cells resulting in infection of T cells. The viral cell-to-cell transmission takes place at the DC-T cell interface termed the infectious synapse. Recent studies demonstrate that direct infection of DCs contributes to the transmission to T cells at a later phase. Moreover, the infected DCs may function as cellular reservoirs for HIV-1. This review discusses the different processes that govern viral piracy of DCs by HIV-1, emphasizing the intracellular routing of the virus from capture on the cell surface to egress in the infectious synapse.

  4. Epigenetic regulation of HIV-1 latency by cytosine methylation.

    Directory of Open Access Journals (Sweden)

    Steven E Kauder

    2009-06-01

    Full Text Available Human immunodeficiency virus type 1 (HIV-1 persists in a latent state within resting CD4+ T cells of infected persons treated with highly active antiretroviral therapy (HAART. This reservoir must be eliminated for the clearance of infection. Using a cDNA library screen, we have identified methyl-CpG binding domain protein 2 (MBD2 as a regulator of HIV-1 latency. Two CpG islands flank the HIV-1 transcription start site and are methylated in latently infected Jurkat cells and primary CD4+ T cells. MBD2 and histone deacetylase 2 (HDAC2 are found at one of these CpG islands during latency. Inhibition of cytosine methylation with 5-aza-2'deoxycytidine (aza-CdR abrogates recruitment of MBD2 and HDAC2. Furthermore, aza-CdR potently synergizes with the NF-kappaB activators prostratin or TNF-alpha to reactivate latent HIV-1. These observations confirm that cytosine methylation and MBD2 are epigenetic regulators of HIV-1 latency. Clearance of HIV-1 from infected persons may be enhanced by inclusion of DNA methylation inhibitors, such as aza-CdR, and NF-kappaB activators into current antiviral therapies.

  5. Tetherin does not significantly restrict dendritic cell-mediated HIV-1 transmission and its expression is upregulated by newly synthesized HIV-1 Nef

    Directory of Open Access Journals (Sweden)

    Wu Li

    2011-04-01

    Full Text Available Abstract Background Dendritic cells (DCs are among the first cells to encounter HIV-1 and play important roles in viral transmission and pathogenesis. Immature DCs allow productive HIV-1 replication and long-term viral dissemination. The pro-inflammatory factor lipopolysaccharide (LPS induces DC maturation and enhances the efficiency of DC-mediated HIV-1 transmission. Type I interferon (IFN partially inhibits HIV-1 replication and cell-cell transmission in CD4+ T cells and macrophages. Tetherin is a type I IFN-inducible restriction factor that blocks HIV-1 release and modulates CD4+ T cell-mediated cell-to-cell transmission of HIV-1. However, the role of type I IFN and tetherin in HIV-1 infection of DCs and DC-mediated viral transmission remains unknown. Results We demonstrated that IFN-alpha (IFNα-induced mature DCs restricted HIV-1 replication and trans-infection of CD4+ T cells. Tetherin expression in monocyte-derived immature DCs was undetectable or very low. High levels of tetherin were transiently expressed in LPS- and IFNα-induced mature DCs, while HIV-1 localized into distinct patches in these DCs. Knockdown of induced tetherin in LPS- or IFNα-matured DCs modestly enhanced HIV-1 transmission to CD4+ T cells, but had no significant effect on wild-type HIV-1 replication in mature DCs. Intriguingly, we found that HIV-1 replication in immature DCs induced significant tetherin expression in a Nef-dependent manner. Conclusions The restriction of HIV-1 replication and transmission in IFNα-induced mature DCs indicates a potent anti-HIV-1 response; however, high levels of tetherin induced in mature DCs cannot significantly restrict wild-type HIV-1 release and DC-mediated HIV-1 transmission. Nef-dependent tetherin induction in HIV-1-infected immature DCs suggests an innate immune response of DCs to HIV-1 infection.

  6. Phenotypic Knockout of HIV-1 Chemokine Coreceptor CXCR4 and CCR5 by Intrakines for Blocking HIV-1 Infection

    Institute of Scientific and Technical Information of China (English)

    张颖; 张岩; 王平忠; 王九平; 黄长形; 孙永涛; 白雪帆

    2004-01-01

    To investigate the phenotypic knockout of HIV-1 chemokine coreceptor CXCR4 and CCR5 by intrakines and its inhibitory effect on HIV-1 infection. Primary human PBLs were transduced with the recombinant vector pLNCX-R-K-S-K(△NGFR), followed by anti-NGFR/anti-IgG-magnetic bead method selection and FCM detection. The transduced PBLs were infected with DP1 HIV-1 virus thereafter envelope-mediated syncytium formation and p24 detection were carried out to study the blockage of HIV-1 infection by co-inactivation of CCR5 and CXCR4. pLNCX-R-K-S-K (△NGFR)-transduced PBILs were isolated with an anti-NGFR/anti-IgG-magnetic bead method. After isolation, about 70% of the PBLs were positive for the NGFR marker. When the transduced PBLs were infected with DP1 HIV-1 virus, envelop-mediated syncytium formation was almost completely inhibited by pLNCX-R-K-S-K(△NGFR) transfection. Also, p24 antigen was very low in the cultures of pLNCX-R-K-S-K (△NGFR) transduced PBLs. pLNCX-R-K-S-K(△NGFR) transduction inhibited the production of DP1 p24 antigen by 15%, 43% and 19% on days 4, 7 and 10 respectively. The lymphocytes with the phenotypic knockout of CCR5 and CXCR4 could protect primary human PBLs from DP1 HIV-1 virus infection.

  7. HIV-1C疫苗研究进展%Advances in the Research of HIV-1 Subtype C Vaccine

    Institute of Scientific and Technical Information of China (English)

    王晶晶; 寸韡

    2008-01-01

    对于HIV-1,抗逆转录病毒药物能显著改善HIV/AIDS病人的健康并延长其寿命.但高昂的费用和治疗条件令大多数HIV患者望而却步,尤其在感染水平高、公共资源极度匮乏的发展中国家.到2004年底,撒哈拉以南非洲地区有2540万HIV感染者,该地区迄今仍是HIV-1C感染最严重的地区.几种候选HIV-1C疫苗目前正在进行临床前和临床研究.这些候选疫苗的设计主要是来自HIV-1C的HIV-1调控蛋白和结构蛋白.本文重点介绍HIV-1C疫苗的研究进展.

  8. Cell-specific RNA aptamer against human CCR5 specifically targets HIV-1 susceptible cells and inhibits HIV-1 infectivity.

    Science.gov (United States)

    Zhou, Jiehua; Satheesan, Sangeetha; Li, Haitang; Weinberg, Marc S; Morris, Kevin V; Burnett, John C; Rossi, John J

    2015-03-19

    The C-C chemokine receptor type 5 (CCR5) is a receptor expressed by T cells and macrophages that serves as a coreceptor for macrophage-tropic HIV-1. Loss of CCR5 is associated with resistance to HIV-1. Here, we combine the live-cell-based SELEX with high-throughput sequencing technology to generate CCR5 RNA aptamers capable of specifically targeting HIV-1 susceptible cells (as small interfering RNA [siRNA] delivery agent) and inhibiting HIV-1 infectivity (as antiviral agent) via block of the CCR5 required for HIV-1 to enter cells. One of the best candidates, G-3, efficiently bound and was internalized into human CCR5-expressing cells. The G-3 specifically neutralized R5 virus infection in primary peripheral blood mononuclear cells, and in vivo generated human CD4(+) T cells with a nanomolar inhibitory concentration 50%. G-3 was also capable of transferring functional siRNAs to CCR5-expressing cells. Collectively, the cell-specific, internalizing, CCR5-targeted aptamers and aptamer-siRNA conjugates offer promise for overcoming some of the current challenges of drug resistance in HIV-1 by providing cell-type- or tissue-specific delivery of various therapeutic moieties.

  9. Tactics used by HIV-1 to evade host innate, adaptive, and intrinsic immunities

    Institute of Scientific and Technical Information of China (English)

    LU Lu; YU Fei; DU Lan-ying; XU Wei; JIANG Shi-bo

    2013-01-01

    Objective To review the mechanisms by which HIV evades different components of the host immune system.Data sources This review is based on data obtained from published articles from 1991 to 2012.To perform the PubMed literature search,the following key words were input:HIV and immune evasion.Study selection Articles containing information related to HIV immune evasion were selected.Results Although HIV is able to induce vigorous antiviral immune responses,viral replication cannot be fully controlled,and neither pre-existing infected cells nor latent HIV infection can be completely eradicated.Like many other enveloped viruses,HIV can escape recognition by the innate and adaptive immune systems.Recent findings have demonstrated that HIV can also successfully evade host restriction factors,the components of intrinsic immune system,such as APOBEC3G (apolipoprotein B mRNA-editing enzyme,catalytic polypeptide-like 3G),TRIM5α (tripartite motif 5-α),tetherin,and SAMHD1 (SAM-domain HD-domain containing protein).Conclusions HIV immune evasion plays an important role in HIV pathcgenesis.Fully understanding the tactics deployed by HIV to evade various components of the host immune systems will allow for the development of novel strategies aimed toward the prevention and cure of HIV/AIDS.

  10. HIV-1 Vif与机体内在抗病毒因子APOBEC3G的研究进展

    Institute of Scientific and Technical Information of China (English)

    李岚(综述); 杨怡姝(综述); 李泽琳(审校); 曾毅(审校)

    2005-01-01

    近期研究表明,非允许性细胞中存在的载脂蛋白B mRNA编辑酶催化多肽样蛋白3G(APOBEC3G)是机体内在的抗病毒因子,它在人免疫缺陷病毒(HIV)反转录过程中,使所形成的负链cDNA中的胞嘧啶脱氨,进而降低病毒的感染力.而Vif蛋白可结合APOBEC3G,并激活泛素-蛋白酶体途径,使之降解,拮抗APOBEC3G的抗病毒活性,且二者之间的相互作用还存在种属特异性.Vif与APOBEC3G间的相互作用,为抗HIV药物的研究提供了新靶点.

  11. HIV-1 evades innate immune recognition through specific cofactor recruitment

    Science.gov (United States)

    Rasaiyaah, Jane; Tan, Choon Ping; Fletcher, Adam J.; Price, Amanda J.; Blondeau, Caroline; Hilditch, Laura; Jacques, David A.; Selwood, David L.; James, Leo C.; Noursadeghi, Mahdad; Towers, Greg J.

    2013-11-01

    Human immunodeficiency virus (HIV)-1 is able to replicate in primary human macrophages without stimulating innate immunity despite reverse transcription of genomic RNA into double-stranded DNA, an activity that might be expected to trigger innate pattern recognition receptors. We reasoned that if correctly orchestrated HIV-1 uncoating and nuclear entry is important for evasion of innate sensors then manipulation of specific interactions between HIV-1 capsid and host factors that putatively regulate these processes should trigger pattern recognition receptors and stimulate type 1 interferon (IFN) secretion. Here we show that HIV-1 capsid mutants N74D and P90A, which are impaired for interaction with cofactors cleavage and polyadenylation specificity factor subunit 6 (CPSF6) and cyclophilins (Nup358 and CypA), respectively, cannot replicate in primary human monocyte-derived macrophages because they trigger innate sensors leading to nuclear translocation of NF-κB and IRF3, the production of soluble type 1 IFN and induction of an antiviral state. Depletion of CPSF6 with short hairpin RNA expression allows wild-type virus to trigger innate sensors and IFN production. In each case, suppressed replication is rescued by IFN-receptor blockade, demonstrating a role for IFN in restriction. IFN production is dependent on viral reverse transcription but not integration, indicating that a viral reverse transcription product comprises the HIV-1 pathogen-associated molecular pattern. Finally, we show that we can pharmacologically induce wild-type HIV-1 infection to stimulate IFN secretion and an antiviral state using a non-immunosuppressive cyclosporine analogue. We conclude that HIV-1 has evolved to use CPSF6 and cyclophilins to cloak its replication, allowing evasion of innate immune sensors and induction of a cell-autonomous innate immune response in primary human macrophages.

  12. Phylodynamics of the HIV-1 epidemic in Cuba.

    Directory of Open Access Journals (Sweden)

    Edson Delatorre

    Full Text Available Previous studies have shown that the HIV-1 epidemic in Cuba displayed a complex molecular epidemiologic profile with circulation of several subtypes and circulating recombinant forms (CRF; but the evolutionary and population history of those viral variants remains unknown. HIV-1 pol sequences of the most prevalent Cuban lineages (subtypes B, C and G, CRF18_cpx, CRF19_cpx, and CRFs20/23/24_BG isolated between 1999 and 2011 were analyzed. Maximum-likelihood analyses revealed multiple introductions of subtype B (n≥66, subtype C (n≥10, subtype G (n≥8 and CRF18_cpx (n≥2 viruses in Cuba. The bulk of HIV-1 infections in this country, however, was caused by dissemination of a few founder strains probably introduced from North America/Europe (clades B(CU-I and B(CU-II, east Africa (clade C(CU-I and central Africa (clades G(CU, CRF18(CU and CRF19(CU, or locally generated (clades CRFs20/23/24_BG. Bayesian-coalescent analyses show that the major HIV-1 founder strains were introduced into Cuba during 1985-1995; whereas the CRFs_BG strains emerged in the second half of the 1990s. Most HIV-1 Cuban clades appear to have experienced an initial period of fast exponential spread during the 1990s and early 2000s, followed by a more recent decline in growth rate. The median initial growth rate of HIV-1 Cuban clades ranged from 0.4 year⁻¹ to 1.6 year⁻¹. Thus, the HIV-1 epidemic in Cuba has been a result of the successful introduction of a few viral strains that began to circulate at a rather late time of the AIDS pandemic, but then were rapidly disseminated through local transmission networks.

  13. Phylodynamics of the HIV-1 epidemic in Cuba.

    Science.gov (United States)

    Delatorre, Edson; Bello, Gonzalo

    2013-01-01

    Previous studies have shown that the HIV-1 epidemic in Cuba displayed a complex molecular epidemiologic profile with circulation of several subtypes and circulating recombinant forms (CRF); but the evolutionary and population history of those viral variants remains unknown. HIV-1 pol sequences of the most prevalent Cuban lineages (subtypes B, C and G, CRF18_cpx, CRF19_cpx, and CRFs20/23/24_BG) isolated between 1999 and 2011 were analyzed. Maximum-likelihood analyses revealed multiple introductions of subtype B (n≥66), subtype C (n≥10), subtype G (n≥8) and CRF18_cpx (n≥2) viruses in Cuba. The bulk of HIV-1 infections in this country, however, was caused by dissemination of a few founder strains probably introduced from North America/Europe (clades B(CU-I) and B(CU-II)), east Africa (clade C(CU-I)) and central Africa (clades G(CU), CRF18(CU) and CRF19(CU)), or locally generated (clades CRFs20/23/24_BG). Bayesian-coalescent analyses show that the major HIV-1 founder strains were introduced into Cuba during 1985-1995; whereas the CRFs_BG strains emerged in the second half of the 1990s. Most HIV-1 Cuban clades appear to have experienced an initial period of fast exponential spread during the 1990s and early 2000s, followed by a more recent decline in growth rate. The median initial growth rate of HIV-1 Cuban clades ranged from 0.4 year⁻¹ to 1.6 year⁻¹. Thus, the HIV-1 epidemic in Cuba has been a result of the successful introduction of a few viral strains that began to circulate at a rather late time of the AIDS pandemic, but then were rapidly disseminated through local transmission networks.

  14. Impaired production of cytokines is an independent predictor of mortality in HIV-1-infected patients

    DEFF Research Database (Denmark)

    Ostrowski, Sisse R; Gerstoft, Jan; Pedersen, Bente K;

    2003-01-01

    With regard to the natural history of HIV-1 infection this study investigated whether whole-blood culture cytokine production was associated with mortality in HIV-1-infected patients.......With regard to the natural history of HIV-1 infection this study investigated whether whole-blood culture cytokine production was associated with mortality in HIV-1-infected patients....

  15. Characterization of natural polymorphic sites of the HIV-1 integrase before the introduction of HIV-1 integrase inhibitors in Germany

    Directory of Open Access Journals (Sweden)

    Karolin Meixenberger

    2014-11-01

    Full Text Available Introduction: The aim of our study was to analyze the occurrence and evolution of HIV-1 integrase polymorphisms during the HIV-1 epidemic in Germany prior to the introduction of the first integrase inhibitor raltegravir in 2007. Materials and Methods: Plasma samples from drug-naïve HIV-1 infected individuals newly diagnosed between 1986 and 2006 were used to determine PCR-based population sequences of the HIV-1 integrase (amino acids 1–278. The HIV-1 subtype was determined using the REGA HIV-1 subtyping tool. We calculated the frequency of amino acids at each position of the HIV-1 integrase in 337 subtype B strains for the time periods 1986–1989, 1991–1994, 1995–1998, 1999–2002, and 2003–2006. Positions were defined as polymorphic if amino acid variation was >1% in any period. Logistic regression was used to identify trends in amino acid variation over time. Resistance-associated mutations were identified according to the IAS 2013 list and the HIVdb, ANRS and GRADE algorithms. Results: Overall, 56.8% (158/278 amino acid positions were polymorphic and 15.8% (25/158 of these positions exhibited a significant trend in amino acid variation over time. Proportionately, most polymorphic positions (63.3%, 31/49 were detected in the N-terminal zinc finger domain of the HIV-1 integrase. Motifs and residues essential for HIV-1 integrase activity were little polymorphic, but within the minimal non-specific DNA binding region I220-D270 up to 18.1% amino acid variation was noticed, including four positions with significant amino acid variation over time (S230, D232, D256, A265. No major resistance mutations were identified, and minor resistance mutations were rarely observed without trend over time. E157Q considered by HIVdb, ANRS, and GRADE algorithms was the most frequent resistance-associated polymorphism with an overall prevalence of 2.4%. Conclusions: Detailed knowledge of the evolutionary variation of HIV-1 integrase polymorphisms is

  16. IL-7 Induces SAMHD1 Phosphorylation in CD4+ T Lymphocytes, Improving Early Steps of HIV-1 Life Cycle

    Directory of Open Access Journals (Sweden)

    Mayte Coiras

    2016-03-01

    Full Text Available HIV-1 post-integration latency in CD4+ lymphocytes is responsible for viral persistence despite treatment, but mechanisms involved in the establishment of latent viral reservoirs are not fully understood. We determined that both interleukin 2 (IL-2 and IL-7 induced SAMHD1 phosphorylation in T592, abrogating its antiviral activity. However, IL-7 caused a much more profound stimulatory effect on HIV-1 reverse transcription and integration than IL-2 that required chemokine co-stimulation. Both cytokines barely induced transcription due to low NF-κB induction, favoring the establishment of latent reservoirs. Effect of IL-7 on SAMHD1 phosphorylation was confirmed in IL-7-treated patients (ACTG 5214 study. Dasatinib—a tyrosine-kinase inhibitor—blocked SAMHD1 phosphorylation induced by IL-2 and IL-7 and restored HIV-1 restriction. We propose that γc-cytokines play a major role in the reservoir establishment not only by driving homeostatic proliferation but also by increasing susceptibility of CD4+ lymphocytes to HIV-1 infection through SAMHD1 inactivation.

  17. Association between polymorphisms of the APOBEC3G gene and chronic hepatitis B viral infection and hepatitis B virus-related hepatocellular carcinoma

    Science.gov (United States)

    He, Xiu-Ting; Xu, Hong-Qin; Wang, Xiao-Mei; He, Xiu-Shu; Niu, Jun-Qi; Gao, Pu-Jun

    2017-01-01

    AIM To determine the relationship between five A3G gene single nucleotide polymorphisms and the incidence of hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC). METHODS This association study was designed as a retrospective study, including 657 patients with chronic HBV infection (CHB) and 299 healthy controls. All subjects were ethnic Han Chinese. Chronic HBV-infected patients recruited between 2012 and 2015 at The First Hospital of Jilin University (Changchun) were further classified into HBV-related HCC patients (n = 287) and non-HCC patients (n = 370). Frequency matching by age and sex was performed for each group. Human genomic DNA was extracted from whole blood. Gene polymorphisms were identified using a mass spectroscopic method. RESULTS There were no significant differences between the genotype and allele frequencies of the rs7291971, rs5757465 and rs5757463 A3G gene polymorphisms, and risk of CHB and HBV-related HCC. The AG genotype and G allele for rs8177832 were significantly related to a decreased risk of CHB (OR = 0.67, 95%CI: 0.47-0.96; OR = 0.69, 95%CI: 0.50-0.95, respectively) and HCC (OR = 0.53, 95%CI: 0.34-0.84; OR = 0.58, 95%CI: 0.39-0.87, respectively). A significant relationship was found between rs2011861 computed tomography, TT genotypes and increased risk of HCC (OR = 1.69, 95%CI: 1.02-2.80; OR = 1.82, 95%CI: 1.08-3.06, respectively). Haplotype analyses showed three protective and four risk haplotypes for HCC. Also, one protective haplotype was found against CHB. CONCLUSION This study indicates that the A3G rs8177832 polymorphism is associated with a decreased risk of CHB infection and HCC, while the rs2011861 polymorphism is associated with an increased risk of HCC. PMID:28127197

  18. Role of semen in HIV-1 transmission: inhibitor or facilitator?

    Science.gov (United States)

    Doncel, Gustavo F; Joseph, Theresa; Thurman, Andrea R

    2011-03-01

    Sexual transmission of human immunodeficiency virus type 1 (HIV-1) accounts for 60-90% of new infections, especially in developing countries. During male-to-female transmission, the virus is typically deposited in the vagina as cell-free and cell-associated virions carried by semen. But semen is more than just a carrier for HIV-1. Evidence from in vitro and in vivo studies supports both inhibitory and enhancing effects. Intrinsic antiviral activity mediated by cationic antimicrobial peptides, cytotoxicity, and blockage of HIV-dendritic cell interactions are seminal plasma properties that inhibit HIV-1 infection. On the contrary, neutralization of vaginal acidic pH, enhanced virus-target cell attachment by seminal amyloid fibrils, opsonization by complement fragments, and electrostatic interactions are factors that facilitate HIV-1 infection. The end result, i.e., inhibition or enhancement of HIV mucosal infection, in vivo, likely depends on the summation of all these biological effects. More research is needed, especially in animal models, to dissect the role of these factors and establish their relevance in HIV-1 transmission.

  19. Raltegravir cerebrospinal fluid concentrations in HIV-1 infection.

    Directory of Open Access Journals (Sweden)

    Aylin Yilmaz

    Full Text Available INTRODUCTION: Raltegravir is an HIV-1 integrase inhibitor currently used in treatment-experienced HIV-1-infected patients resistant to other drug classes. In order to assess its central nervous system penetration, we measured raltegravir concentrations in cerebrospinal fluid (CSF and plasma in subjects receiving antiretroviral treatment regimens containing this drug. METHODS: Raltegravir concentrations were determined by liquid chromatography tandem mass spectrometry in 25 paired CSF and plasma samples from 16 HIV-1-infected individuals. The lower limit of quantitation was 2.0 ng/ml for CSF and 10 ng/ml for plasma. RESULTS: Twenty-four of the 25 CSF samples had detectable raltegravir concentrations with a median raltegravir concentration of 18.4 ng/ml (range, <2.0-126.0. The median plasma raltegravir concentration was 448 ng/ml (range, 37-5180. CSF raltegravir concentrations correlated with CSF:plasma albumin ratios and CSF albumin concentrations. CONCLUSIONS: Approximately 50% of the CSF specimens exceeded the IC(95 levels reported to inhibit HIV-1 strains without resistance to integrase inhibitors. In addition to contributing to control of systemic HIV-1 infection, raltegravir achieves local inhibitory concentrations in CSF in most, but not all, patients. Blood-brain and blood-CSF barriers likely restrict drug entry, while enhanced permeability of these barriers enhances drug entry.

  20. HIV-1, human interaction database: current status and new features.

    Science.gov (United States)

    Ako-Adjei, Danso; Fu, William; Wallin, Craig; Katz, Kenneth S; Song, Guangfeng; Darji, Dakshesh; Brister, J Rodney; Ptak, Roger G; Pruitt, Kim D

    2015-01-01

    The 'Human Immunodeficiency Virus Type 1 (HIV-1), Human Interaction Database', available through the National Library of Medicine at http://www.ncbi.nlm.nih.gov/genome/viruses/retroviruses/hiv-1/interactions, serves the scientific community exploring the discovery of novel HIV vaccine candidates and therapeutic targets. Each HIV-1 human protein interaction can be retrieved without restriction by web-based downloads and ftp protocols and includes: Reference Sequence (RefSeq) protein accession numbers, National Center for Biotechnology Information Gene identification numbers, brief descriptions of the interactions, searchable keywords for interactions and PubMed identification numbers (PMIDs) of journal articles describing the interactions. In addition to specific HIV-1 protein-human protein interactions, included are interaction effects upon HIV-1 replication resulting when individual human gene expression is blocked using siRNA. A total of 3142 human genes are described participating in 12,786 protein-protein interactions, along with 1316 replication interactions described for each of 1250 human genes identified using small interfering RNA (siRNA). Together the data identifies 4006 human genes involved in 14,102 interactions. With the inclusion of siRNA interactions we introduce a redesigned web interface to enhance viewing, filtering and downloading of the combined data set.

  1. HIV-1 subtype B: Traces of a pandemic.

    Science.gov (United States)

    Junqueira, Dennis Maletich; Almeida, Sabrina Esteves de Matos

    2016-08-01

    Human migration is a major process that shaped the origin and dissemination of HIV. Within HIV-1, subtype B (HIV-1B) is the most disseminated variant and it is assumed to be the causative agent in approximately 11% of all cases of HIV worldwide. Phylogenetic studies have revealed that HIV-1B emerged in Kinshasa (Africa) and was introduced into the Caribbean region via Haiti in or around 1966 by human migration. After localized dispersion, the virus was brought to the United States of America via homosexual/bisexual contact around 1969. Inside USA, the incidence of HIV-1B infection increased exponentially and it became established in the population, affecting not only homosexual individuals but also heterosexual individuals and injecting drug users. Soon after, the virus was disseminated and became established in other regions, including Europe, Asia, Latin America, and Australia. Recent studies suggest that, in addition to this pandemic clade, several lineages have emerged from Haiti and reached other Caribbean and Latin American countries via short-distance dissemination. Different subtype B genetic variants have also been detected in these epidemics. Four genetic variants have been described to date: subtype B', which mainly circulates in Thailand and other Asian countries; a specific variant mainly found in Trinidad and Tobago; the GPGS variant, which is primarily detected in Korea; and the GWGR variant, which is mainly detected in Brazil. This paper reviews the evolution of HIV-1B and its impact on the human population.

  2. HIV-1 neutralization: mechanisms and relevance to vaccine design.

    Science.gov (United States)

    Zwick, Michael B; Burton, Dennis R

    2007-11-01

    Antibody (Ab) mediated neutralization is a crucial means of host resistance to many pathogens and will most likely be required in the development of a vaccine to protect against HIV-1. Here we examine mechanistic aspects of HIV-1 neutralization with attention to recent studies on the stoichiometric, kinetic and thermodynamic parameters involved. Neutralization of HIV-1, as with any microbe, minimally requires an initial molecular encounter with Ab. Ab occupancy of functional heterotrimers of the envelope glycoproteins, gp120 and gp41 (Env), indeed appears to be the dominant mechanism of neutralization for HIV-1. However, the Ab-binding site, the parameters mentioned above, as well as the stages and duration of vulnerability to Ab recognition, prior to and leading up to viral entry, each have a distinct impact on the mechanism of neutralization for any given Ab specificity. With HIV-1, the problems of mutational variation and neutralization resistance, coupled with the lability and conformational heterogeneity in Env, have stimulated the search for rational approaches to Env immunogen design that are unprecedented in vaccinology.

  3. Vif proteins of human and simian immunodeficiency viruses require cellular CBFβ to degrade APOBEC3 restriction factors.

    Science.gov (United States)

    Hultquist, Judd F; Binka, Mawuena; LaRue, Rebecca S; Simon, Viviana; Harris, Reuben S

    2012-03-01

    HIV-1 requires the cellular transcription factor CBFβ to stabilize its accessory protein Vif and promote APOBEC3G degradation. Here, we demonstrate that both isoforms of CBFβ allow for increased steady-state levels of Vif, enhanced APOBEC3G degradation, and increased viral infectivity. This conserved functional interaction enhances the steady-state levels of Vif proteins from multiple HIV-1 subtypes and is required for the degradation of all human and rhesus Vif-sensitive APOBEC3 proteins by their respective lentiviral Vif proteins.

  4. An inhibition enzyme immunoassay, using a human monoclonal antibody (K14) reactive with gp41 of HIV-1, for the serology of HIV-1 infections.

    NARCIS (Netherlands)

    V.J.P. Teeuwsen; J.J. Schalken; G. van der Groen (Guido); R. van den Akker (Ruud); J. Goudsmit (Jaap); A.D.M.E. Osterhaus (Albert)

    1991-01-01

    textabstractAn inhibition enzyme immunoassay (IEIA), using a human monoclonal antibody (K14) reactive with gp41 of HIV-1, was evaluated for its applicability to the serology of HIV-1 infections. Using panels of serum samples from seronegative and confirmed HIV-1-seropositive individuals, it was show

  5. Glycosylation in HIV-1 envelope glycoprotein and its biological implications

    KAUST Repository

    Ho, Yung Shwen

    2013-08-01

    Glycosylation of HIV-1 envelope proteins (Env gp120/gp41) plays a vital role in viral evasion from the host immune response, which occurs through the masking of key neutralization epitopes and the presentation of the Env glycosylation as \\'self\\' to the host immune system. Env glycosylation is generally conserved, yet its continual evolution plays an important role in modulating viral infectivity and Env immunogenicity. Thus, it is believed that Env glycosylation, which is a vital part of the HIV-1 architecture, also controls intra- and inter-clade genetic variations. Discerning intra- and inter-clade glycosylation variations could therefore yield important information for understanding the molecular and biological differences between HIV clades and may assist in effectively designing Env-based immunogens and in clearly understanding HIV vaccines. This review provides an in-depth perspective of various aspects of Env glycosylation in the context of HIV-1 pathogenesis. © 2013 Future Medicine Ltd.

  6. Oral and systemic manifestations in HIV-1 patients

    Directory of Open Access Journals (Sweden)

    Tatiany Oliveira de Alencar Menezes

    2015-02-01

    Full Text Available INTRODUCTION: This study aimed to estimate the prevalence of the most frequent oral and systemic manifestations in human immunodeficiency virus-1 (HIV-1-positive patients. METHODS: The study was conducted on 300 HIV-1 patients attending the Reference Unit Specialized in Special Infectious Parasitic Diseases in Belém, Pará, Brazil. RESULTS: The most prevalent oral conditions were caries (32.6%, candidiasis (32%, and periodontal disease (17%. Among the systemic manifestations, hepatitis (29.2%, gastritis (16%, arterial hypertension (14.7%, and tuberculosis (12% were the most commonly observed. CONCLUSIONS: We here reported on the most prevalent oral and systemic conditions in HIV-1-positive patients. The healthcare professional's knowledge of the various manifestations among these patients is fundamental to ensure prompt and accurate diagnosis and treatment, and for improving the quality of life of these patients.

  7. Raltegravir with optimized background therapy for resistant HIV-1 infection

    DEFF Research Database (Denmark)

    Steigbigel, Roy T; Cooper, David A; Kumar, Princy N;

    2008-01-01

    for the length of follow-up, cancers were detected in 3.5% of raltegravir recipients and in 1.7% of placebo recipients. The overall frequencies of drug-related adverse events were similar in the raltegravir and placebo groups. CONCLUSIONS: In HIV-infected patients with limited treatment options, raltegravir plus......BACKGROUND: Raltegravir (MK-0518) is an inhibitor of human immunodeficiency virus type 1 (HIV-1) integrase active against HIV-1 susceptible or resistant to older antiretroviral drugs. METHODS: We conducted two identical trials in different geographic regions to evaluate the safety and efficacy...... of raltegravir, as compared with placebo, in combination with optimized background therapy, in patients infected with HIV-1 that has triple-class drug resistance in whom antiretroviral therapy had failed. Patients were randomly assigned to raltegravir or placebo in a 2:1 ratio. RESULTS: In the combined studies...

  8. 2´,3´-Dialdehyde of ATP, ADP, and adenosine inhibit HIV-1 reverse transcriptase and HIV-1 replication.

    Science.gov (United States)

    Schachter, Julieta; Valadao, Ana Luiza Chaves; Aguiar, Renato Santana; Barreto-de-Souza, Victor; Rossi, Atila Duque; Arantes, Pablo Ricardo; Verli, Hugo; Quintana, Paula Gabriela; Heise, Norton; Tanuri, Amilcar; Bou-Habib, Dumith Chequer; Persechini, Pedro Muanis

    2014-01-01

    The 2´3´-dialdehyde of ATP or oxidized ATP (oATP) is a compound known for specifically making covalent bonds with the nucleotide-binding site of several ATP-binding enzymes and receptors. We investigated the effects of oATP and other oxidized purines on HIV-1 infection and we found that this compound inhibits HIV-1 and SIV infection by blocking early steps of virus replication. oATP, oxidized ADP (oADP), and oxidized Adenosine (oADO) impact the natural activity of endogenous reverse transcriptase enzyme (RT) in cell free virus particles and are able to inhibit viral replication in different cell types when added to the cell cultures either before or after infection. We used UFLC-UV to show that both oADO and oATP can be detected in the cell after being added in the extracellular medium. oATP also suppresses RT activity and replication of the HIV-1 resistant variants M184V and T215Y. We conclude that oATP, oADP and oADO display anti HIV-1 activity that is at in least in part due to inhibitory activity on HIV-1 RT.

  9. Flail arm-like syndrome associated with HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Nalini A

    2009-01-01

    Full Text Available During the last 20 years at least 23 cases of motor neuron disease have been reported in HIV-1 seropositive patients. In this report we describe the clinical picture of a young man with HIV-1 clade C infection and flail arm-like syndrome, who we were able to follow-up for a long period. We investigated and prospectively monitored a 34-year-old man with features of flail arm syndrome, who developed the weakness and wasting 1 year after being diagnosed with HIV-1 infection after a routine blood test. He presented in 2003 with progressive, symmetrical wasting and weakness of the proximal muscles of the upper limb of 2 years′ duration. He had severe wasting and weakness of the shoulder and arm muscles. There were no pyramidal signs. He has been on HAART for the last 4 years and the weakness or wasting has not worsened. At the last follow-up in July 2007, the patient had the same neurological deficit and no other symptoms or signs of HIV-1 infection. MRI of the spinal cord in 2007 showed characteristic T2 hyperintense signals in the central part of the spinal cord, corresponding to the central gray matter. Thus, our patient had HIV-1 clade C infection associated with a ′flail arm-like syndrome.′ The causal relationship between HIV-1 infection and amyotrophic lateral sclerosis (ALS-like syndrome is still uncertain. The syndrome usually manifests as a lower motor neuron syndrome, as was seen in our young patient. It is known that treatment with antiretroviral therapy (ART stabilizes/improves the condition. In our patient the weakness and atrophy remained stable over a period of 3.5 years after commencing HAART regimen.

  10. Genotypic and functional properties of early infant HIV-1 envelopes

    Directory of Open Access Journals (Sweden)

    Sullivan John L

    2011-08-01

    Full Text Available Abstract Background Understanding the properties of HIV-1 variants that are transmitted from women to their infants is crucial to improving strategies to prevent transmission. In this study, 162 full-length envelope (env clones were generated from plasma RNA obtained from 5 HIV-1 Clade B infected mother-infant pairs. Following extensive genotypic and phylogenetic analyses, 35 representative clones were selected for functional studies. Results Infant quasispecies were highly homogeneous and generally represented minor maternal variants, consistent with transmission across a selective bottleneck. Infant clones did not differ from the maternal in env length, or glycosylation. All infant variants utilized the CCR5 co-receptor, but were not macrophage tropic. Relatively high levels (IC50 ≥ 100 μg/ml of autologous maternal plasma IgG were required to neutralize maternal and infant viruses; however, all infant viruses were neutralized by pooled sera from HIV-1 infected individuals, implying that they were not inherently neutralization-resistant. All infant viruses were sensitive to the HIV-1 entry inhibitors Enfuvirtide and soluble CD4; none were resistant to Maraviroc. Sensitivity to human monoclonal antibodies 4E10, 2F5, b12 and 2G12 varied. Conclusions This study provides extensive characterization of the genotypic and functional properties of HIV-1 env shortly after transmission. We present the first detailed comparisons of the macrophage tropism of infant and maternal env variants and their sensitivity to Maraviroc, the only CCR5 antagonist approved for therapeutic use. These findings may have implications for improving approaches to prevent mother-to-child HIV-1 transmission.

  11. A novel peptide that inhibits HIV-1 entry

    Institute of Scientific and Technical Information of China (English)

    YU Yong; HUANG Xiaoxing; WANG Qiong; YANG Yaling; TIAN Po; ZHANG Wentao

    2004-01-01

    @@ The global epidemic of HIV infection, the cause of AIDS, has created an urgent need for novel classes of antiretroviral agent. Besides reverse transcriptase and protease, the viral entry process provides new anti-HIV-1 targets. A new generation of antiviral drugs intended to block HIV entry into host cells is now under develop- ment[1]. These compounds are generally referred to as fusion or entry inhibitor. Several HIV-1 entry inhibitors that target CD4-gp120 interactions, co-receptor function, and gp41-mediated membrane fusion are in different stages of clinical development[2].

  12. Recognition of HIV-1 peptides by host CTL is related to HIV-1 similarity to human proteins.

    Directory of Open Access Journals (Sweden)

    Morgane Rolland

    Full Text Available BACKGROUND: While human immunodeficiency virus type 1 (HIV-1-specific cytotoxic T lymphocytes preferentially target specific regions of the viral proteome, HIV-1 features that contribute to immune recognition are not well understood. One hypothesis is that similarities between HIV and human proteins influence the host immune response, i.e., resemblance between viral and host peptides could preclude reactivity against certain HIV epitopes. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed the extent of similarity between HIV-1 and the human proteome. Proteins from the HIV-1 B consensus sequence from 2001 were dissected into overlapping k-mers, which were then probed against a non-redundant database of the human proteome in order to identify segments of high similarity. We tested the relationship between HIV-1 similarity to host encoded peptides and immune recognition in HIV-infected individuals, and found that HIV immunogenicity could be partially modulated by the sequence similarity to the host proteome. ELISpot responses to peptides spanning the entire viral proteome evaluated in 314 individuals showed a trend indicating an inverse relationship between the similarity to the host proteome and the frequency of recognition. In addition, analysis of responses by a group of 30 HIV-infected individuals against 944 overlapping peptides representing a broad range of individual HIV-1B Nef variants, affirmed that the degree of similarity to the host was significantly lower for peptides with reactive epitopes than for those that were not recognized. CONCLUSIONS/SIGNIFICANCE: Our results suggest that antigenic motifs that are scarcely represented in human proteins might represent more immunogenic CTL targets not selected against in the host. This observation could provide guidance in the design of more effective HIV immunogens, as sequences devoid of host-like features might afford superior immune reactivity.

  13. Antiviral activity of α-helical stapled peptides designed from the HIV-1 capsid dimerization domain

    Directory of Open Access Journals (Sweden)

    Cowburn David

    2011-05-01

    Full Text Available Abstract Background The C-terminal domain (CTD of HIV-1 capsid (CA, like full-length CA, forms dimers in solution and CTD dimerization is a major driving force in Gag assembly and maturation. Mutations of the residues at the CTD dimer interface impair virus assembly and render the virus non-infectious. Therefore, the CTD represents a potential target for designing anti-HIV-1 drugs. Results Due to the pivotal role of the dimer interface, we reasoned that peptides from the α-helical region of the dimer interface might be effective as decoys to prevent CTD dimer formation. However, these small peptides do not have any structure in solution and they do not penetrate cells. Therefore, we used the hydrocarbon stapling technique to stabilize the α-helical structure and confirmed by confocal microscopy that this modification also made these peptides cell-penetrating. We also confirmed by using isothermal titration calorimetry (ITC, sedimentation equilibrium and NMR that these peptides indeed disrupt dimer formation. In in vitro assembly assays, the peptides inhibited mature-like virus particle formation and specifically inhibited HIV-1 production in cell-based assays. These peptides also showed potent antiviral activity against a large panel of laboratory-adapted and primary isolates, including viral strains resistant to inhibitors of reverse transcriptase and protease. Conclusions These preliminary data serve as the foundation for designing small, stable, α-helical peptides and small-molecule inhibitors targeted against the CTD dimer interface. The observation that relatively weak CA binders, such as NYAD-201 and NYAD-202, showed specificity and are able to disrupt the CTD dimer is encouraging for further exploration of a much broader class of antiviral compounds targeting CA. We cannot exclude the possibility that the CA-based peptides described here could elicit additional effects on virus replication not directly linked to their ability to bind

  14. HIV-1 infection of in vitro cultured human monocytes: early events and influence of anti HIV-1 antibodies

    DEFF Research Database (Denmark)

    Arendrup, M; Olofsson, S; Nielsen, Jens Ole;

    1994-01-01

    on this infection. Depending on the period of in vitro cultivation and the virus isolate used different patterns of susceptibility were detected. One week old monocyte/M phi s were highly susceptible to HIV-1 infection, in contrast to monocyte/M phi s cultured 4 weeks. The infection by virus isolated immediately...... to CD4 and that post binding events may be common to the infection of lymphocytes. Anti HIV-1 sera showed neutralizing activity against heterologous and even autologous escape virus. This finding, together with the observation that monocytes and M phi s are infected in vivo, suggests that protection...

  15. CXCR4-tropic HIV-1 suppresses replication of CCR5-tropic HIV-1 in human lymphoid tissue by selective induction of CC-chemokines.

    Science.gov (United States)

    Ito, Yoshinori; Grivel, Jean-Charles; Chen, Silvia; Kiselyeva, Yana; Reichelderfer, Patricia; Margolis, Leonid

    2004-02-01

    In infected individuals, human immunodeficiency virus type 1 (HIV-1) exist as a "swarm" of quasi species compartmentalized in tissues where individual viral variants may interact locally. We have used human lymphoid tissue, where the critical events of HIV disease occur, to study local interactions in model HIV-1 binary swarms ex vivo. We infected tissue blocks with binary mixtures consisting either of CCR5-dependent and CXCR4-dependent variants or of 2 dual-tropic HIV-1 variants, of which one is skewed to utilization of CXCR4 and the other of CCR5. HIV-1 variants that use CXCR4 suppress replication of CCR5-dependent HIV-1 variants, whereas CCR5-dependent HIV-1 variants do not affect replication of CXCR4-dependent HIV-1. CC-chemokines that inhibit replication of CCR5-dependent HIV-1 variants were up-regulated by CXCR4-dependent HIV-1, thus possibly contributing to this suppression. Tissue-specific chemokine/cytokine network modulations triggered by individual HIV-1 variants may be an important mechanism of local interactions among HIV-1 quasi species in infected tissue.

  16. Prediction of the secondary structure of HIV-1 gp120

    DEFF Research Database (Denmark)

    Hansen, J E; Lund, O; Nielsen, Jens Ole

    1996-01-01

    The secondary structure of HIV-1 gp120 was predicted using multiple alignment and a combination of two independent methods based on neural network and nearest-neighbor algorithms. The methods agreed on the secondary structure for 80% of the residues in BH10 gp120. Six helices were predicted in HIV...

  17. Effects of human SAMHD1 polymorphisms on HIV-1 susceptibility

    Energy Technology Data Exchange (ETDEWEB)

    White, Tommy E.; Brandariz-Nuñez, Alberto; Valle-Casuso, Jose Carlos [Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, 1301 Morris Park – Price Center 501, New York, NY 10461 (United States); Knowlton, Caitlin; Kim, Baek [Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642 (United States); Sawyer, Sara L. [Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712 (United States); Diaz-Griffero, Felipe, E-mail: Felipe.Diaz-Griffero@einstein.yu.edu [Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, 1301 Morris Park – Price Center 501, New York, NY 10461 (United States)

    2014-07-15

    SAMHD1 is a human restriction factor that prevents efficient infection of macrophages, dendritic cells and resting CD4+ T cells by HIV-1. Here we explored the antiviral activity and biochemical properties of human SAMHD1 polymorphisms. Our studies focused on human SAMHD1 polymorphisms that were previously identified as evolving under positive selection for rapid amino acid replacement during primate speciation. The different human SAMHD1 polymorphisms were tested for their ability to block HIV-1, HIV-2 and equine infectious anemia virus (EIAV). All studied SAMHD1 variants block HIV-1, HIV-2 and EIAV infection when compared to wild type. We found that these variants did not lose their ability to oligomerize or to bind RNA. Furthermore, all tested variants were susceptible to degradation by Vpx, and localized to the nuclear compartment. We tested the ability of human SAMHD1 polymorphisms to decrease the dNTP cellular levels. In agreement, none of the different SAMHD1 variants lost their ability to reduce cellular levels of dNTPs. Finally, we found that none of the tested human SAMHD1 polymorphisms affected the ability of the protein to block LINE-1 retrotransposition. - Highlights: • Human SAMHD1 single-nucleotide polymorphisms block HIV-1 and HIV-2 infection. • SAMHD1 polymorphisms do not affect its ability to block LINE-1 retrotransposition. • SAMHD1 polymorphisms decrease the cellular levels of dNTPs.

  18. Interplay between the RNA interference machinery and HIV-1

    NARCIS (Netherlands)

    Schopman, N.C.T.

    2012-01-01

    Resistente infecties zijn lastig te behandelen. Nick Schopman onderzocht een verbeterde RNA-interferentie (RNAi)-gebaseerde anti-hiv-1 gentherapie. Dit kan in de toekomst leiden tot een nieuwe aanpak van de behandeling van resistente infecties. Schopman beschrijft een nieuw ontwerp van een RNAi-mole

  19. Is the central nervous system a reservoir of HIV-1?

    Science.gov (United States)

    Gray, Lachlan R.; Roche, Michael; Flynn, Jacqueline K.; Wesselingh, Steve L.; Gorry, Paul R.; Churchill, Melissa J.

    2014-01-01

    Purpose of the review To summarize the evidence in the literature that supports the CNS as a viral reservoir for HIV-1 and to prioritise future research efforts. Recent findings HIV-1 DNA has been detected in brain tissue of patients with undetectable viral load or neurocognitive disorders, and is associated with long-lived cells such as astrocytes and microglia. In neurocognitively normal patients, HIV-1 can be found at high frequency in these cells (4% of astrocytes and 20% of macrophages). CNS cells have unique molecular mechanisms to suppress viral replication and induce latency, which include increased expression of dominant negative transcription factors and suppressive epigenetic factors. There is also evidence of continued inflammation in patients lacking a CNS viral load, suggesting the production and activity of viral neurotoxins (for example Tat). Summary Together, these findings provide evidence that the CNS can potentially act as a viral reservoir of HIV-1. However, the majority of these studies were performed in historical cohorts (absence of cART or presence of viral load) which do not reflect modern day patients (cART-treated and undetectable viral load). Future studies will need to examine patient samples with these characteristics to conclusively determine if the CNS represents a relevant and important viral reservoir. PMID:25203642

  20. The Immune Interaction between HIV-1 Infection and Mycobacterium tuberculosis.

    Science.gov (United States)

    Du Bruyn, Elsa; Wilkinson, Robert John

    2016-12-01

    The modulation of tuberculosis (TB)-induced immunopathology caused by human immunodeficiency virus (HIV)-1 coinfection remains incompletely understood but underlies the change seen in the natural history, presentation, and prognosis of TB in such patients. The deleterious combination of these two pathogens has been dubbed a "deadly syndemic," with each favoring the replication of the other and thereby contributing to accelerated disease morbidity and mortality. HIV-1 is the best-recognized risk factor for the development of active TB and accounts for 13% of cases globally. The advent of combination antiretroviral therapy (ART) has considerably mitigated this risk. Rapid roll-out of ART globally and the recent recommendation by the World Health Organization (WHO) to initiate ART for everyone living with HIV at any CD4 cell count should lead to further reductions in HIV-1-associated TB incidence because susceptibility to TB is inversely proportional to CD4 count. However, it is important to note that even after successful ART, patients with HIV-1 are still at increased risk for TB. Indeed, in settings of high TB incidence, the occurrence of TB often remains the first presentation of, and thereby the entry into, HIV care. As advantageous as ART-induced immune recovery is, it may also give rise to immunopathology, especially in the lower-CD4-count strata in the form of the immune reconstitution inflammatory syndrome. TB-immune reconstitution inflammatory syndrome will continue to impact the HIV-TB syndemic.

  1. Pharmacokinetics of antiretroviral therapy in HIV-1-infected children

    NARCIS (Netherlands)

    P.L.A. Fraaij (Pieter); J.J.A. van Kampen (Jeroen); D.M. Burger (David); R. de Groot (Ronald)

    2005-01-01

    textabstractThe initiation of antiretroviral therapy has resulted in an impressive reduction in the rate of disease progression in AIDS and HIV-1-related deaths in children; however, there are still several major challenges to be faced in order to improve therapy. A major topic that needs to be deal

  2. New insights into HIV-1-primary skin disorders.

    Science.gov (United States)

    Cedeno-Laurent, Filiberto; Gómez-Flores, Minerva; Mendez, Nora; Ancer-Rodríguez, Jesús; Bryant, Joseph L; Gaspari, Anthony A; Trujillo, Jose R

    2011-01-24

    Since the first reports of AIDS, skin involvement has become a burdensome stigma for seropositive patients and a challenging task for dermatologist and infectious disease specialists due to the severe and recalcitrant nature of the conditions. Dermatologic manifestations in AIDS patients act as markers of disease progression, a fact that enhances the importance of understanding their pathogenesis.Broadly, cutaneous disorders associated with HIV type-1 infection can be classified as primary and secondary. While the pathogenesis of secondary complications, such as opportunistic infections and skin tumours, is directly correlated with a decline in the CD4+ T cell count, the origin of the certain manifestations primarily associated with the retroviral infection itself still remains under investigation.The focus of this review is to highlight the immunological phenomena that occur in the skin of HIV-1-seropositive patients, which ultimately lead to skin disorders, such as seborrhoeic dermatitis, atopic dermatitis, psoriasis and eosinophilic folliculitis. Furthermore, we compile the latest data on how shifts in the cytokines milieu, impairments of the innate immune compartment, reactions to xenobiotics and autoimmunity are causative agents in HIV-1-driven skin diseases. Additionally, we provide a thorough analysis of the small animal models currently used to study HIV-1-associated skin complications, centering on transgenic rodent models, which unfortunately, have not been able to fully unveil the role of HIV-1 genes in the pathogenesis of their primarily associated dermatological manifestations.

  3. New insights into HIV-1-primary skin disorders

    Directory of Open Access Journals (Sweden)

    Cedeno-Laurent Filiberto

    2011-01-01

    Full Text Available Abstract Since the first reports of AIDS, skin involvement has become a burdensome stigma for seropositive patients and a challenging task for dermatologist and infectious disease specialists due to the severe and recalcitrant nature of the conditions. Dermatologic manifestations in AIDS patients act as markers of disease progression, a fact that enhances the importance of understanding their pathogenesis. Broadly, cutaneous disorders associated with HIV type-1 infection can be classified as primary and secondary. While the pathogenesis of secondary complications, such as opportunistic infections and skin tumours, is directly correlated with a decline in the CD4+ T cell count, the origin of the certain manifestations primarily associated with the retroviral infection itself still remains under investigation. The focus of this review is to highlight the immunological phenomena that occur in the skin of HIV-1-seropositive patients, which ultimately lead to skin disorders, such as seborrhoeic dermatitis, atopic dermatitis, psoriasis and eosinophilic folliculitis. Furthermore, we compile the latest data on how shifts in the cytokines milieu, impairments of the innate immune compartment, reactions to xenobiotics and autoimmunity are causative agents in HIV-1-driven skin diseases. Additionally, we provide a thorough analysis of the small animal models currently used to study HIV-1-associated skin complications, centering on transgenic rodent models, which unfortunately, have not been able to fully unveil the role of HIV-1 genes in the pathogenesis of their primarily associated dermatological manifestations.

  4. New insights into complications and treatment of HIV-1 infection

    NARCIS (Netherlands)

    van Lelyveld, S.F.L.

    2013-01-01

    In this thesis the complications and treatment of HIV-1 infection in the current era was studied. Life expectancy of HIV-infected patients has increased enormously with the introduction of combination antiretroviral therapy (cART). In line with this observation, we found that the outcome of HIV-infe

  5. Impact of chemotherapy for HIV-1 related lymphoma on residual viremia and cellular HIV-1 DNA in patients on suppressive antiretroviral therapy.

    Science.gov (United States)

    Cillo, Anthony R; Krishnan, Supriya; McMahon, Deborah K; Mitsuyasu, Ronald T; Para, Michael F; Mellors, John W

    2014-01-01

    The first cure of HIV-1 infection was achieved through complex, multimodal therapy including myeloablative chemotherapy, total body irradiation, anti-thymocyte globulin, and allogeneic stem cell transplantation with a CCR5 delta32 homozygous donor. The contributions of each component of this therapy to HIV-1 eradication are unclear. To assess the impact of cytotoxic chemotherapy alone on HIV-1 persistence, we longitudinally evaluated low-level plasma viremia and HIV-1 DNA in PBMC from patients in the ACTG A5001/ALLRT cohort on suppressive antiretroviral therapy (ART) who underwent chemotherapy for HIV-1 related lymphoma without interrupting ART. Plasma HIV-1 RNA, total HIV-1 DNA and 2-LTR circles (2-LTRs) in PBMC were measured using sensitive qPCR assays. In the 9 patients who received moderately intensive chemotherapy for HIV-1 related lymphoma with uninterrupted ART, low-level plasma HIV-1 RNA did not change significantly with chemotherapy: median HIV-1 RNA was 1 copy/mL (interquartile range: 1.0 to 20) pre-chemotherapy versus 4 copies/mL (interquartile range: 1.0 to 7.0) post-chemotherapy. HIV-1 DNA levels also did not change significantly, with median pre-chemotherapy HIV-1 DNA of 355 copies/106 CD4+ cells versus 228 copies/106 CD4+ cells post-chemotherapy. 2-LTRs were detectable in 2 of 9 patients pre-chemotherapy and in 3 of 9 patients post-chemotherapy. In summary, moderately intensive chemotherapy for HIV-1 related lymphoma in the context of continuous ART did not have a prolonged impact on HIV-1 persistence. Clinical trials registration unique identifier: NCT00001137.

  6. High levels of CC-chemokine expression and downregulated levels of CCR5 during HIV-1/HTLV-1 and HIV-1/HTLV-2 coinfections.

    Science.gov (United States)

    Oo, Z; Barrios, C S; Castillo, L; Beilke, M A

    2015-05-01

    The human T-cell lymphotropic virus type 1 (HTLV-1) and HTLV-2 are common copathogens among Human Immunodeficiency Virus (HIV)-infected individuals. HTLV-2 may confer a survival benefit among patients with HIV-1/HTLV-2 coinfections, along with lower plasma HIV-1 levels and delayed rates of CD4(+) T-cell decline. These effects have been attributed to the ability of the HTLV-2 viral transactivating Tax2 protein to induce the production of high levels of antiviral CC-chemokines and to downregulate expression of the CCR5 receptor, resulting in impaired entry of HIV-1 into CD4(+) T-cells. This study investigated the innate immunity of coinfected HIV/HTLV individuals by testing the ability of patient PBMCs to produce CC-chemokines in association CCR5 receptor modulation. The cellular proliferative responses of HIV/HTLV coinfected versus HIV monoinfected individuals were also evaluated. Higher levels of MIP-1α, MIP-1β, and RANTES (P HIV-1/HTLV-2 coinfected group compared to HIV-1 monoinfected population. Upregulated levels of RANTES were shown in HIV-1/HTLV-1 after 1 and 3 days of culture (P HIV-1/HTLV-2 coinfected individuals showed significant CCR5 downregulation after 1 and 3 days of culture compared to lymphocytes from HIV-1 and uninfected groups (P CCR5-positive cells were found in HIV-1/HTLV-1 coinfected after 3 days of incubation (P HIV-1/HTLV-1 group compared to HIV-1 alone (P HIV-1 via stimulation of CC-chemokines and receptors, potentially modifying CCR5/HIV-1 binding and HIV-1 progression in coinfected individuals.

  7. Characteristics of HIV-1 discordant couples enrolled in a trial of HSV-2 suppression to reduce HIV-1 transmission: the partners study.

    Directory of Open Access Journals (Sweden)

    Jairam R Lingappa

    Full Text Available BACKGROUND: The Partners HSV-2/HIV-1 Transmission Study (Partners Study is a phase III, placebo-controlled trial of daily acyclovir for genital herpes (HSV-2 suppression among HIV-1/HSV-2 co-infected persons to reduce HIV-1 transmission to their HIV-1 susceptible partners, which requires recruitment of HIV-1 serodiscordant heterosexual couples. We describe the baseline characteristics of this cohort. METHODS: HIV-1 serodiscordant heterosexual couples, in which the HIV-1 infected partner was HSV-2 seropositive, had a CD4 count >or=250 cells/mcL and was not on antiretroviral therapy, were enrolled at 14 sites in East and Southern Africa. Demographic, behavioral, clinical and laboratory characteristics were assessed. RESULTS: Of the 3408 HIV-1 serodiscordant couples enrolled, 67% of the HIV-1 infected partners were women. Couples had cohabitated for a median of 5 years (range 2-9 with 28% reporting unprotected sex in the month prior to enrollment. Among HIV-1 susceptible participants, 86% of women and 59% of men were HSV-2 seropositive. Other laboratory-diagnosed sexually transmitted infections were uncommon (500 relative to <350, respectively, p<0.001. CONCLUSIONS: The Partners Study successfully enrolled a cohort of 3408 heterosexual HIV-1 serodiscordant couples in Africa at high risk for HIV-1 transmission. Follow-up of this cohort will evaluate the efficacy of acyclovir for HSV-2 suppression in preventing HIV-1 transmission and provide insights into biological and behavioral factors determining heterosexual HIV-1 transmission. TRIAL REGISTRATION: ClinicalTrials.gov NCT00194519.

  8. Impact of chemotherapy for HIV-1 related lymphoma on residual viremia and cellular HIV-1 DNA in patients on suppressive antiretroviral therapy.

    Directory of Open Access Journals (Sweden)

    Anthony R Cillo

    Full Text Available The first cure of HIV-1 infection was achieved through complex, multimodal therapy including myeloablative chemotherapy, total body irradiation, anti-thymocyte globulin, and allogeneic stem cell transplantation with a CCR5 delta32 homozygous donor. The contributions of each component of this therapy to HIV-1 eradication are unclear. To assess the impact of cytotoxic chemotherapy alone on HIV-1 persistence, we longitudinally evaluated low-level plasma viremia and HIV-1 DNA in PBMC from patients in the ACTG A5001/ALLRT cohort on suppressive antiretroviral therapy (ART who underwent chemotherapy for HIV-1 related lymphoma without interrupting ART. Plasma HIV-1 RNA, total HIV-1 DNA and 2-LTR circles (2-LTRs in PBMC were measured using sensitive qPCR assays. In the 9 patients who received moderately intensive chemotherapy for HIV-1 related lymphoma with uninterrupted ART, low-level plasma HIV-1 RNA did not change significantly with chemotherapy: median HIV-1 RNA was 1 copy/mL (interquartile range: 1.0 to 20 pre-chemotherapy versus 4 copies/mL (interquartile range: 1.0 to 7.0 post-chemotherapy. HIV-1 DNA levels also did not change significantly, with median pre-chemotherapy HIV-1 DNA of 355 copies/106 CD4+ cells versus 228 copies/106 CD4+ cells post-chemotherapy. 2-LTRs were detectable in 2 of 9 patients pre-chemotherapy and in 3 of 9 patients post-chemotherapy. In summary, moderately intensive chemotherapy for HIV-1 related lymphoma in the context of continuous ART did not have a prolonged impact on HIV-1 persistence. Clinical trials registration unique identifier: NCT00001137.

  9. In vitro nuclear interactome of the HIV-1 Tat protein.

    LENUS (Irish Health Repository)

    Gautier, Virginie W

    2009-01-01

    BACKGROUND: One facet of the complexity underlying the biology of HIV-1 resides not only in its limited number of viral proteins, but in the extensive repertoire of cellular proteins they interact with and their higher-order assembly. HIV-1 encodes the regulatory protein Tat (86-101aa), which is essential for HIV-1 replication and primarily orchestrates HIV-1 provirus transcriptional regulation. Previous studies have demonstrated that Tat function is highly dependent on specific interactions with a range of cellular proteins. However they can only partially account for the intricate molecular mechanisms underlying the dynamics of proviral gene expression. To obtain a comprehensive nuclear interaction map of Tat in T-cells, we have designed a proteomic strategy based on affinity chromatography coupled with mass spectrometry. RESULTS: Our approach resulted in the identification of a total of 183 candidates as Tat nuclear partners, 90% of which have not been previously characterised. Subsequently we applied in silico analysis, to validate and characterise our dataset which revealed that the Tat nuclear interactome exhibits unique signature(s). First, motif composition analysis highlighted that our dataset is enriched for domains mediating protein, RNA and DNA interactions, and helicase and ATPase activities. Secondly, functional classification and network reconstruction clearly depicted Tat as a polyvalent protein adaptor and positioned Tat at the nexus of a densely interconnected interaction network involved in a range of biological processes which included gene expression regulation, RNA biogenesis, chromatin structure, chromosome organisation, DNA replication and nuclear architecture. CONCLUSION: We have completed the in vitro Tat nuclear interactome and have highlighted its modular network properties and particularly those involved in the coordination of gene expression by Tat. Ultimately, the highly specialised set of molecular interactions identified will

  10. Accuracy of the TRUGENE HIV-1 Genotyping Kit

    Science.gov (United States)

    Grant, Robert M.; Kuritzkes, Daniel R.; Johnson, Victoria A.; Mellors, John W.; Sullivan, John L.; Swanstrom, Ronald; D'Aquila, Richard T.; Van Gorder, Mark; Holodniy, Mark; Lloyd, Jr., Robert M.; Reid, Caroline; Morgan, Gillian F.; Winslow, Dean L.

    2003-01-01

    Drug resistance and poor virological responses are associated with well-characterized mutations in the viral reading frames that encode the proteins that are targeted by currently available antiretroviral drugs. An integrated system was developed that includes target gene amplification, DNA sequencing chemistry (TRUGENE HIV-1 Genotyping Kit), and hardware and interpretative software (the OpenGene DNA Sequencing System) for detection of mutations in the human immunodeficiency virus type 1 (HIV-1) protease and reverse transcriptase sequences. The integrated system incorporates reverse transcription-PCR from extracted HIV-1 RNA, a coupled amplification and sequencing step (CLIP), polyacrylamide gel electrophoresis, semiautomated analysis of data, and generation of an interpretative report. To assess the accuracy and robustness of the assay system, 270 coded plasma specimens derived from nine patients were sent to six laboratories for blinded analysis. All specimens contained HIV-1 subtype B viruses. Results of 270 independent assays were compared to “gold standard” consensus sequences of the virus populations determined by sequence analysis of 16 to 20 clones of viral DNA amplicons derived from two independent PCRs using primers not used in the kit. The accuracy of the integrated system for nucleotide base identification was 98.7%, and the accuracy for codon identification at 54 sites associated with drug resistance was 97.6%. In a separate analysis of plasma spiked with infectious molecular clones, the assay reproducibly detected all 72 different drug resistance mutations that were evaluated. There were no significant differences in accuracy between laboratories, between technologists, between kit lots, or between days. This integrated assay system for the detection of HIV-1 drug resistance mutations has a high degree of accuracy and reproducibility in several laboratories. PMID:12682149

  11. Innate antiviral immune signaling, viral evasion and modulation by HIV-1.

    Science.gov (United States)

    Rustagi, Arjun; Gale, Michael

    2014-03-20

    The intracellular innate antiviral response in human cells is an essential component of immunity against virus infection. As obligate intracellular parasites, all viruses must evade the actions of the host cell's innate immune response in order to replicate and persist. Innate immunity is induced when pathogen recognition receptors of the host cell sense viral products including nucleic acid as "non-self". This process induces downstream signaling through adaptor proteins to activate latent transcription factors that drive the expression of genes encoding antiviral and immune modulatory effector proteins that restrict virus replication and regulate adaptive immunity. The interferon regulatory factors (IRFs) are transcription factors that play major roles in innate immunity. In particular, IRF3 is activated in response to infection by a range of viruses including RNA viruses, DNA viruses and retroviruses. Among these viruses, human immunodeficiency virus type 1 (HIV-1) remains a major global health problem mediating chronic infection in millions of people wherein recent studies show that viral persistence is linked with the ability of the virus to dysregulate and evade the innate immune response. In this review, we discuss viral pathogen sensing, innate immune signaling pathways and effectors that respond to viral infection, the role of IRF3 in these processes and how it is regulated by pathogenic viruses. We present a contemporary overview of the interplay between HIV-1 and innate immunity, with a focus on understanding how innate immune control impacts infection outcome and disease.

  12. HIV-1 DNA vaccine with adjuvant cytokines induces specific immune responses against HIV-1 infection in mice

    Institute of Scientific and Technical Information of China (English)

    WANG Fu-xiang; SUN Yong-tao; WANG Lin-xu; LIU Juan

    2006-01-01

    @@ There is mounting evidence that the induction of strong mucosal and cell-mediated immune responses is key element to consider in constructing efficacious HIV-1 vaccine. Therapeutic vaccines that induce high levels of CTL specific to HIV are currently being developed worldwide.

  13. Emergence of minor drug-resistant HIV-1 variants after triple antiretroviral prophylaxis for prevention of vertical HIV-1 transmission.

    Directory of Open Access Journals (Sweden)

    Andrea Hauser

    Full Text Available BACKGROUND: WHO-guidelines for prevention of mother-to-child transmission of HIV-1 in resource-limited settings recommend complex maternal antiretroviral prophylaxis comprising antenatal zidovudine (AZT, nevirapine single-dose (NVP-SD at labor onset and AZT/lamivudine (3TC during labor and one week postpartum. Data on resistance development selected by this regimen is not available. We therefore analyzed the emergence of minor drug-resistant HIV-1 variants in Tanzanian women following complex prophylaxis. METHOD: 1395 pregnant women were tested for HIV-1 at Kyela District Hospital, Tanzania. 87/202 HIV-positive women started complex prophylaxis. Blood samples were collected before start of prophylaxis, at birth and 1-2, 4-6 and 12-16 weeks postpartum. Allele-specific real-time PCR assays specific for HIV-1 subtypes A, C and D were developed and applied on samples of mothers and their vertically infected infants to quantify key resistance mutations of AZT (K70R/T215Y/T215F, NVP (K103N/Y181C and 3TC (M184V at detection limits of <1%. RESULTS: 50/87 HIV-infected women having started complex prophylaxis were eligible for the study. All women took AZT with a median duration of 53 days (IQR 39-64; all women ingested NVP-SD, 86% took 3TC. HIV-1 resistance mutations were detected in 20/50 (40% women, of which 70% displayed minority species. Variants with AZT-resistance mutations were found in 11/50 (22%, NVP-resistant variants in 9/50 (18% and 3TC-resistant variants in 4/50 women (8%. Three women harbored resistant HIV-1 against more than one drug. 49/50 infants, including the seven vertically HIV-infected were breastfed, 3/7 infants exhibited drug-resistant virus. CONCLUSION: Complex prophylaxis resulted in lower levels of NVP-selected resistance as compared to NVP-SD, but AZT-resistant HIV-1 emerged in a substantial proportion of women. Starting AZT in pregnancy week 14 instead of 28 as recommended by the current WHO-guidelines may further increase

  14. German-austrian recommendations for HIV1-therapy in pregnancy and in HIV1-exposed newborn - update 2008

    Directory of Open Access Journals (Sweden)

    Buchholz Bernd

    2009-11-01

    Full Text Available Abstract German-Austrian recommendations for HIV1-therapy in pregnancy - Update 2008 Bernd Buchholz (University Medical Centre Mannheim, Pediatric Clinic, Matthias Beichert (Mannheim, Gynecology and Obstetrics Practice, Ulrich Marcus (Robert Koch Institute, Berlin, Thomas Grubert, Andrea Gingelmaier (Gynecology Clinic of the Ludwig Maximilians University of Munich, Dr. med. Annette Haberl (HIV-Department, J. W. Goethe-University Hospital, Frankfurt, Dr. med. Brigitte Schmied (Otto-Wagner Spital, Wien. In Germany during the last years about 200-250 HIV1-infected pregnant women delivered a baby each year, a number that is currently increasing. To determine the HIV-status early in pregnancy voluntary HIV-testing of all pregnant women is recommended in Germany and Austria as part of prenatal care. In those cases, where HIV1-infection was known during pregnancy, since 1995 the rate of vertical transmission of HIV1 was reduced to 1-2%. This low transmission rate has been achieved by the combination of anti-retroviral therapy of pregnant women, caesarean section scheduled before onset of labour, anti-retroviral post exposition prophylaxis in the newborn and refraining from breast-feeding by the HIV1-infected mother. To keep pace with new results in research, approval of new anti-retroviral drugs and changes in the general treatment recommendations for HIV1-infected adults, in 1998, 2001, 2003 and 2005 an interdisciplinary consensus meeting was held. Gynaecologists, infectious disease specialists, paediatricians, pharmacologists, virologists and members of the German AIDS Hilfe (NGO were participating in this conference to update the prevention strategies. A fifth update became necessary in 2008. The updating process was started in January 2008 and was terminated in September 2008. The guidelines provide new recommendations on the indication and the starting point for HIV-therapy in pregnancies without complications, drugs and drug combinations to be

  15. Progress in Research on Drug-resistance of HIV-1%HIV-1耐药性的研究进展

    Institute of Scientific and Technical Information of China (English)

    贾峥

    2011-01-01

    The drug-resistance of HIV-1 is one of the important cause for failure in treatment of AIDS in humans.The research on drug-resistance of HIV-1 is of an important significance in controlling the epidemic of drug-resistance HIV-1 strain and clinical therapy of AIDS.This paper reviews the generation, evolution and epidemic of drug-resistant strain, mechanism of drug-resistance, drug-resistant mutation, test for drug-resistance as well as novel methods for drug-resistance test of HIV-1.%HIV-1耐药株的出现是人类艾滋病(AIDS)治疗失败的重要原因之一,HIV-1耐药性的研究对于控制耐药株的流行及临床治疗真有重要意义.本文就HIV-1耐药株的产生、进化和传播,HIV-1的耐药机制及耐药性突变,HIV-1耐药性检测以及新型HIV-1耐药性检测方法等作一综述.

  16. Clinical presentation and opportunistic infections in HIV-1, HIV-2 and HIV-1/2 dual seropositive patients in Guinea-Bissau

    DEFF Research Database (Denmark)

    Sørensen, Allan; Jespersen, Sanne; Katzenstein, Terese L;

    2016-01-01

    BACKGROUND: Better understanding of HIV-2 infection is likely to affect the patient care in areas where HIV-2 is prevalent. In this study, we aimed to characterize the clinical presentations among HIV-1, HIV-2 and HIV-1/2 dual seropositive patients. METHODS: In a cross-sectional study, newly...... diagnosed HIV patients attending the HIV outpatient clinic at Hospital Nacional Simão Mendes in Guinea-Bissau were enrolled. Demographical and clinical data were collected and compared between HIV-1, HIV-2 and HIV-1/2 dual seropositive patients. RESULTS: A total of 169 patients (76% HIV-1, 17% HIV-2 and 6......% HIV 1/2) were included in the study between 21 March 2012 and 14 December 2012. HIV-1 seropositive patients were younger than HIV-2 and HIV-1/2 seropositive patients, but no difference in sex was observed. Patients with HIV-1 and HIV-1/2 had a lower baseline CD4 cell count than HIV-2 seropositive...

  17. Mosaic clade M human immunodeficiency virus type 1 (HIV-1) envelope immunogens

    Science.gov (United States)

    Korber, Bette T.; Fischer, William; Liao, Hua-Xin; Haynes, Barton F.; Letvin, Norman; Hahn; Beatrice H.

    2011-05-31

    The present invention relates to mosaic clade M HIV-1 Env polypeptides and to compositions comprising same. The polypeptides of the invention are suitable for use in inducing an immune response to HIV-1 in a human.

  18. Maturation Pathways of Cross-Reactive HIV-1 Neutralizing Antibodies

    Directory of Open Access Journals (Sweden)

    Dimiter S. Dimitrov

    2009-11-01

    Full Text Available Several human monoclonal antibodies (hmAbs and antibody fragments, including the best characterized in terms of structure-function b12 and Fab X5, exhibit relatively potent and broad HIV-1 neutralizing activity. However, the elicitation of b12 or b12-like antibodies in vivo by vaccine immunogens based on the HIV-1 envelope glycoprotein (Env has not been successful. B12 is highly divergent from the closest corresponding germline antibody while X5 is less divergent. We have hypothesized that the relatively high degree of specific somatic hypermutations may preclude binding of the HIV-1 envelope glycoprotein (Env to closest germline antibodies, and that identifying antibodies that are intermediates in the pathways to maturation could help design novel vaccine immunogens to guide the immune system for their enhanced elicitation. In support of this hypothesis we have previously found that a germline-like b12 (monovalent and bivalent scFv as an Fc fusion protein or IgG lacks measurable binding to an Env as measured by ELISA with a sensitivity in the μM range [1]; here we present evidence confirming and expanding these findings for a panel of Envs. In contrast, a germline-like scFv X5 bound Env with high (nM affinity. To begin to explore the maturation pathways of these antibodies we identified several possible b12 intermediate antibodies and tested their neutralizing activity. These intermediate antibodies neutralized only some HIV-1 isolates and with relatively weak potency. In contrast, germline-like scFv X5 neutralized a subset of the tested HIV-1 isolates with comparable efficiencies to that of the mature X5. These results could help explain the relatively high immunogenicity of the coreceptor binding site on gp120 and the abundance of CD4-induced (CD4i antibodies in HIV-1-infected patients (X5 is a CD4i antibody as well as the maturation pathway of X5. They also can help identify antigens that can bind specifically to b12 germline and

  19. Contrasting roles for TLR ligands in HIV-1 pathogenesis.

    Directory of Open Access Journals (Sweden)

    Beda Brichacek

    Full Text Available The first line of a host's response to various pathogens is triggered by their engagement of cellular pattern recognition receptors (PRRs. Binding of microbial ligands to these receptors leads to the induction of a variety of cellular factors that alter intracellular and extracellular environment and interfere directly or indirectly with the life cycle of the triggering pathogen. Such changes may also affect any coinfecting microbe. Using ligands to Toll-like receptors (TLRs 5 and 9, we examined their effect on human immunodeficiency virus (HIV-1 replication in lymphoid tissue ex vivo. We found marked differences in the outcomes of such treatment. While flagellin (TLR5 agonist treatment enhanced replication of CC chemokine receptor 5 (CCR 5-tropic and CXC chemokine receptor 4 (CXCR4-tropic HIV-1, treatment with oligodeoxynucleotide (ODN M362 (TLR9 agonist suppressed both viral variants. The differential effects of these TLR ligands on HIV-1 replication correlated with changes in production of CC chemokines CCL3, CCL4, CCL5, and of CXC chemokines CXCL10, and CXCL12 in the ligand-treated HIV-1-infected tissues. The nature and/or magnitude of these changes were dependent on the ligand as well as on the HIV-1 viral strain. Moreover, the tested ligands differed in their ability to induce cellular activation as evaluated by the expression of the cluster of differentiation markers (CD 25, CD38, CD39, CD69, CD154, and human leukocyte antigen D related (HLA-DR as well as of a cell proliferation marker, Ki67, and of CCR5. No significant effect of the ligand treatment was observed on apoptosis and cell death/loss in the treated lymphoid tissue ex vivo. Our results suggest that binding of microbial ligands to TLRs is one of the mechanisms that mediate interactions between coinfected microbes and HIV-1 in human tissues. Thus, the engagement of appropriate TLRs by microbial molecules or their mimetic might become a new strategy for HIV therapy or prevention.

  20. Incidence and correlates of HIV-1 RNA detection in the breast milk of women receiving HAART for the prevention of HIV-1 transmission.

    Directory of Open Access Journals (Sweden)

    Jennifer A Slyker

    Full Text Available BACKGROUND: The incidence and correlates of breast milk HIV-1 RNA detection were determined in intensively sampled women receiving highly active antiretroviral therapy (HAART for the prevention of mother-to-child HIV-1 transmission. METHODS: Women initiated HAART at 34 weeks of pregnancy. Breast milk was collected every 2-5 days during 1 month postpartum for measurements of cell-associated HIV DNA and cell-free HIV RNA. Plasma and breast milk were also collected at 2 weeks, 1, 3 and 6 months for concurrent HIV-1 RNA and DNA measurements. Regression was used to identify cofactors for breast milk HIV-1 RNA detection. RESULTS: Of 259 breast milk specimens from 25 women receiving HAART, 34 had detectable HIV-1 RNA (13%, incidence 1.4 episodes/100 person-days 95% CI = 0.97-1.9. Fourteen of 25 (56% women had detectable breast milk HIV-1 RNA [mean 2.5 log(10 copies/ml (range 2.0-3.9] at least once. HIV-1 DNA was consistently detected in breast milk cells despite HAART, and increased slowly over time, at a rate of approximately 1 copy/10(6 cells per day (p = 0.02. Baseline CD4, plasma viral load, HAART duration, and frequency of breast problems were similar in women with and without detectable breast milk HIV-1 RNA. Women with detectable breast milk HIV-1 RNA were more likely to be primiparous than women without (36% vs 0%, p = 0.05. Plasma HIV-1 RNA detection (OR = 9.0, 95%CI = 1.8-44 and plasma HIV-1 RNA levels (OR = 12, 95% CI = 2.5-56 were strongly associated with concurrent detection of breast milk HIV-1 RNA. However, no association was found between breast milk HIV-1 DNA level and concurrent breast milk HIV-1 RNA detection (OR = 0.96, 95%CI = 0.54-1.7. CONCLUSIONS: The majority of women on HAART had episodic detection of breast milk HIV-1 RNA. Breast milk HIV-1 RNA detection was associated with systemic viral burden rather than breast milk HIV-1 DNA.

  1. Characteristics of HIV-1 serodiscordant couples enrolled in a clinical trial of antiretroviral pre-exposure prophylaxis for HIV-1 prevention.

    Directory of Open Access Journals (Sweden)

    Andrew Mujugira

    Full Text Available Stable heterosexual HIV-1 serodiscordant couples in Africa have high HIV-1 transmission rates and are a critical population for evaluation of new HIV-1 prevention strategies. The Partners PrEP Study is a randomized, double-blind, placebo-controlled trial of tenofovir and emtricitabine-tenofovir pre-exposure prophylaxis to decrease HIV-1 acquisition within heterosexual HIV-1 serodiscordant couples. We describe the trial design and characteristics of the study cohort.HIV-1 serodiscordant couples, in which the HIV-1 infected partner did not meet national guidelines for initiation of antiretroviral therapy, were enrolled at 9 research sites in Kenya and Uganda. The HIV-1 susceptible partner was randomized to daily oral tenofovir, emtricitabine-tenofovir, or matching placebo with monthly follow-up for 24-36 months.From July 2008 to November 2010, 7920 HIV-1 serodiscordant couples were screened and 4758 enrolled. For 62% (2966/4758 of enrolled couples, the HIV-1 susceptible partner was male. Median age was 33 years for HIV-1 susceptible and HIV-1 infected partners [IQR (28-40 and (26-39 respectively]. Most couples (98% were married, with a median duration of partnership of 7.0 years (IQR 3.0-14.0 and recent knowledge of their serodiscordant status [median 0.4 years (IQR 0.1-2.0]. During the month prior to enrollment, couples reported a median of 4 sex acts (IQR 2-8; 27% reported unprotected sex and 14% of male and 1% of female HIV-1 susceptible partners reported sex with outside partners. Among HIV-1 infected partners, the median plasma HIV-1 level was 3.94 log(10 copies/mL (IQR 3.31-4.53 and median CD4 count was 496 cells/µL (IQR 375-662; the majority (64% had WHO stage 1 HIV-1 disease.Couples at high risk of HIV-1 transmission were rapidly recruited into the Partners PrEP Study, the largest efficacy trial of oral PrEP. (ClinicalTrials.gov NCT00557245.

  2. Field accuracy of fourth-generation rapid diagnostic tests for acute HIV-1: a systematic review

    OpenAIRE

    2015-01-01

    Introduction: Fourth-generation HIV-1 rapid diagnostic tests (RDTs) detect HIV-1 p24 antigen to screen for acute HIV-1. However, diagnostic accuracy during clinical use may be suboptimal. Methods: Clinical sensitivity and specificity of fourth-generation RDTs for acute HIV-1 were collated from field evaluation studies in adults identified by a systematic literature search. Results: Four studies with 17 381 participants from Australia, Swaziland, the United Kingdom and Malawi were identified. ...

  3. Antigen Gene Cloning and Expression of HIV-1 Toward AIDS Vaccine Design Ⅱ. Subtype Classification and Quasi-species Identification of HIV-1

    Institute of Scientific and Technical Information of China (English)

    ZENG Qingping (曾庆平); YANG Ruiyi (杨瑞仪); FENG Liling (冯丽玲); CHEN Zhuhua (陈竹华); ZENG Changhong (曾常红)

    2002-01-01

    Objectives: To analyze subtypes and quasi-species of isolatedviruses from HIV-1 infected individuals among the populationof Guangdong Province, for understanding the molecularepidemioiogical dynamics of local HIV-1 isolates, thus laying afoundation for designing a candidate AIDS vaccine.Methods: By hetero-duplex mobility assay (HMA) andsingle strand conformation poly- morphism (SSCP) analysison amplicons from single-primed polymerase chain reaction(SP-PCR), subtypes and quasi-species of tested HIV-1 isolateswere elucidated, and amplicons were sequenced forconfirmation.Results: Specific amplicons from different subtypes andquasi-species of HIV-1 could be discernible by HMA andSSCP analysis.Conclusion: HIV-1 isolates from different patients might beeither a different subtype or an identical subtype, and HIV-1isolates from an individual were present in a population ofquasi-species.

  4. Involvement of Sp1 in Butyric Acid-Induced HIV-1 Gene Expression

    Directory of Open Access Journals (Sweden)

    Kenichi Imai

    2015-09-01

    Full Text Available Background/Aims: The ability of human immunodeficiency virus-1(HIV-1 to establish latent infection and its re-activation is considered critical for progression of HIV-1 infection. We previously reported that a bacterial metabolite butyric acid, acting as a potent inhibitor of histone deacetylases (HDACs, could lead to induction of HIV-1 transcription; however, the molecular mechanism remains unclear. The aim of this study was to investigate the effect of butyric acid on HIV-1 gene expression. Methods: Butyric acid-mediated HIV-1 gene expression was determined by luciferase assay and Chromatin immunoprecipitation assay. Western blot analysis and ELISA were used for the detection of HIV-1. Results: We found that Sp1 binding sites within the HIV-1 promoter are primarily involved in butyric acid-mediated HIV-1 activation. In fact, Sp1 knockdown by small interfering RNA and the Sp1 inhibitor mithramycin A abolished the effect of butyric acid. We also observed that cAMP response element-binding-binding protein (CBP was required for butyric acid-induced HIV-1 activation. Conclusions: These results suggest that butyric acid stimulates HIV-1 promoter through inhibition of the Sp1-associated HDAC activity and recruitment of CBP to the HIV-1 LTR. Our findings suggest that Sp1 should be considered as one of therapeutic targets in anti-viral therapy against HIV-1 infection aggravated by butyric acid-producing bacteria.

  5. Anti-HIV-1 Activities of 4 Telomerase Restrictors

    Institute of Scientific and Technical Information of China (English)

    YU Xin; WANG Jinghui; de Giuli Morghen; Radaelli A; Zanotto C; Beggio P

    2007-01-01

    MTT Cell Proliferation Assay was used to optimize the concentration of Telomerase Restrictors(TRs) with minimum toxicity to the selected cells. FACSort flow cytometer and Innotest P24 HIV(Human immunodeficiency Virus) antigen mAb ELISA Kit were used to investigate the anti-HIV-1 activities of TRs. The results showed that TRs had low cytotoxicity to the PBMC (Peripheral Blood mononuclear cells) and CEM/GFP if the concentration of TRs was at 50 μmol/L or below, and the supernatant from PBMC pretreated with SHIV and TR1-001 /TR1-002 could not infect the PBMC, while can infect the C8166 with reduced infectivity, which suggested that the TRs may be one of the novel resources for screening anti-HIV-1 agents.

  6. RNA Control of HIV-1 Particle Size Polydispersity

    CERN Document Server

    Faivre-Moskalenko, Cendrine; Thomas, Audrey; Tartour, Kevin; Beck, Yvonne; Iazykov, Maksym; Danial, John; Lourdin, Morgane; Muriaux, Delphine; Castelnovo, Martin

    2014-01-01

    HIV-1, an enveloped RNA virus, produces viral particles that are known to be much more heterogeneous in size than is typical of non-enveloped viruses. We present here a novel strategy to study HIV-1 Viral Like Particles (VLP) assembly by measuring the size distribution of these purified VLPs and subsequent viral cores thanks to Atomic Force Microscopy imaging and statistical analysis. This strategy allowed us to identify whether the presence of viral RNA acts as a modulator for VLPs and cores size heterogeneity in a large population of particles. These results are analyzed in the light of a recently proposed statistical physics model for the self-assembly process. In particular, our results reveal that the modulation of size distribution by the presence of viral RNA is qualitatively reproduced, suggesting therefore an entropic origin for the modulation of RNA uptake by the nascent VLP.

  7. Attenuation of multiple Nef functions in HIV-1 elite controllers

    Directory of Open Access Journals (Sweden)

    Mwimanzi Philip

    2013-01-01

    Full Text Available Abstract Background Impaired HIV-1 Gag, Pol, and Env function has been described in elite controllers (EC who spontaneously suppress plasma viremia to Results In general, EC Nef clones were functional; however, all five activities were significantly lower in EC compared to CP. Nef clones from HLA-B*57-expressing EC exhibited poorer CD4 down-regulation function compared to those from non-B*57 EC, and the number of EC-specific B*57-associated Nef polymorphisms correlated inversely with 4 of 5 Nef functions in these individuals. Conclusion Results indicate that decreased HIV-1 Nef function, due in part to host immune selection pressures, may be a hallmark of the EC phenotype.

  8. Altered sialylation of alveolar macrophages in HIV-1-infected individuals.

    Science.gov (United States)

    Perrin, C; Giordanengo, V; Bannwarth, S; Blaive, B; Lefebvre, J C

    1997-10-01

    In previous studies, we have demonstrated that O-glycans at the surface of HIV-1-infected cell lines were hyposialylated. Moreover, we and others have shown that HIV+ individuals produced autoantibodies that react with hyposialylated CD43, on T cell lines. Since the autoantigen responsible for this abnormal immune response was not easily found in the peripheral blood cells of corresponding patients, we searched for its possible presence in other sites. Using fluorescence staining of alveolar macrophages with various lectins, we show that the binding of the PNA lectin specific for asialo O-glycans is much more efficient on cells from HIV-1-infected individuals. Moreover, the degree of reactivity of PNA is correlated with the clinical stage of the illness.

  9. Construction of HIV-1 Virus-like Particle Vaccine

    Institute of Scientific and Technical Information of China (English)

    ZHAO Dong-hai; ZHANG Xi-zhen; YU Xiang-hui; KONG Wei

    2008-01-01

    The virus-like particle(VLPs) vaccine is an ideal HIV-1 vaccine,which can simultaneously induce a neutralizing antibody reaction and ceil-mediated immunity effectively.In this study,two kinds of plasmids have been used,one can express the HIV-1 main structure proteins,Gagpol and Env,and the other contains an antibiotic gene.The two kinds of plasmids have been cotransfected into 293 cells.A stable cell line that can express Gagpol and Env proteins efficiently and lastingly has been screened.It has been confirmed that Gagpol and Env proteins in the cell culture supernatant can be self-assembled into virus-like particles.The authors have detected the secretion of VLPs in the cell medium,defined the peak of the secretion,and followed and monitored the stability of expression.

  10. Analysis of dinucleotide signatures in HIV-1 subtype B genomes

    Indian Academy of Sciences (India)

    Aridaman Pandit; Jyothirmayi Vadlamudi; Somdatta Sinha

    2013-12-01

    Dinucleotide usage is known to vary in the genomes of organisms. The dinucleotide usage profiles or genome signatures are similar for sequence samples taken from the same genome, but are different for taxonomically distant species. This concept of genome signatures has been used to study several organisms including viruses, to elucidate the signatures of evolutionary processes at the genome level. Genome signatures assume greater importance in the case of host–pathogen interactions, where molecular interactions between the two species take place continuously, and can influence their genomic composition. In this study, analyses of whole genome sequences of the HIV-1 subtype B, a retrovirus that caused global pandemic of AIDS, have been carried out to analyse the variation in genome signatures of the virus from 1983 to 2007.We show statistically significant temporal variations in some dinucleotide patterns highlighting the selective evolution of the dinucleotide profiles of HIV-1 subtype B, possibly a consequence of host specific selection.

  11. HIV-1 Nef breaches placental barrier in rat model.

    Science.gov (United States)

    Singh, Poonam; Agnihotri, Saurabh Kumar; Tewari, Mahesh Chandra; Kumar, Sadan; Sachdev, Monika; Tripathi, Raj Kamal

    2012-01-01

    The vertical transmission of HIV-1 from the mother to fetus is known, but the molecular mechanism regulating this transmission is not fully characterized. The fetus is highly protected by the placenta, which does not permit microbial pathogens to cross the placental barrier. In the present study, a rat model was established to observe the effect of HIV-1 protein Nef on placental barrier. Evans blue dye was used to assay permeability of placental barrier and fourteen day pregnant Sprague Dawley rats were injected intravenously with 2% Evans blue dye along with various concentrations of recombinant Nef. After an hour, animals were sacrificed and dye migration was observed through the assimilation of peripheral blood into fetus. Interestingly, traces of recombinant Nef protein were detected in the embryo as well as amniotic fluid and amniotic membrane along with placenta and uterus. Our study indicates that recombinant HIV-1-Nef protein breaches the placental barrier and allows the migration of Evans blue dye to the growing fetus. Further the concentration of Nef protein in blood is directly proportional to the intensity of dye migration and to the amount of Nef protein detected in uterus, placenta, amniotic membrane, amniotic fluid and embryo. Based on this study, it can be concluded that the HIV-1 Nef protein has a direct effect on breaching of the placental barrier in the model we have established in this study. Our observations will be helpful to understand the molecular mechanisms related to this breach of placental barrier by Nef in humans and may be helpful to identify specific Nef inhibitors.

  12. HIV-1 envelope subregion length variation during disease progression.

    Directory of Open Access Journals (Sweden)

    Marcel E Curlin

    Full Text Available The V3 loop of the HIV-1 Env protein is the primary determinant of viral coreceptor usage, whereas the V1V2 loop region is thought to influence coreceptor binding and participate in shielding of neutralization-sensitive regions of the Env glycoprotein gp120 from antibody responses. The functional properties and antigenicity of V1V2 are influenced by changes in amino acid sequence, sequence length and patterns of N-linked glycosylation. However, how these polymorphisms relate to HIV pathogenesis is not fully understood. We examined 5185 HIV-1 gp120 nucleotide sequence fragments and clinical data from 154 individuals (152 were infected with HIV-1 Subtype B. Sequences were aligned, translated, manually edited and separated into V1V2, C2, V3, C3, V4, C4 and V5 subregions. V1-V5 and subregion lengths were calculated, and potential N-linked glycosylation sites (PNLGS counted. Loop lengths and PNLGS were examined as a function of time since infection, CD4 count, viral load, and calendar year in cross-sectional and longitudinal analyses. V1V2 length and PNLGS increased significantly through chronic infection before declining in late-stage infection. In cross-sectional analyses, V1V2 length also increased by calendar year between 1984 and 2004 in subjects with early and mid-stage illness. Our observations suggest that there is little selection for loop length at the time of transmission; following infection, HIV-1 adapts to host immune responses through increased V1V2 length and/or addition of carbohydrate moieties at N-linked glycosylation sites. V1V2 shortening during early and late-stage infection may reflect ineffective host immunity. Transmission from donors with chronic illness may have caused the modest increase in V1V2 length observed during the course of the pandemic.

  13. Detection of Acute HIV-1 Infection by RT-LAMP.

    Directory of Open Access Journals (Sweden)

    Donna L Rudolph

    Full Text Available A rapid, cost-effective diagnostic test for the detection of acute HIV-1 infection is highly desired. Isothermal amplification techniques, such as reverse-transcription loop-mediated isothermal amplification (RT-LAMP, exhibit characteristics that are ideal for the development of a rapid nucleic acid amplification test (NAAT because they are quick, easy to perform and do not require complex, dedicated equipment and laboratory space. In this study, we assessed the ability of the HIV-1 RT-LAMP assay to detect acute HIV infection as compared to a representative rapid antibody test and several FDA-approved laboratory-based assays. The HIV-1 RT-LAMP assay detected seroconverting individuals one to three weeks earlier than a rapid HIV antibody test and up to two weeks earlier than a lab-based antigen/antibody (Ag/Ab combo enzyme immunoassay (EIA. RT-LAMP was not as sensitive as a lab-based qualitative RNA assay, which could be attributed to the significantly smaller nucleic acid input volume. To our knowledge, this is the first demonstration of detecting acute HIV infection using the RT-LAMP assay. The availability of a rapid NAAT, such as the HIV-1 RT-LAMP assay, at the point of care (POC or in laboratories that do not have access to large platform NAAT could increase the percentage of individuals who receive an acute HIV infection status or confirmation of their HIV status, while immediately linking them to counseling and medical care. In addition, early knowledge of HIV status could lead to reduced high-risk behavior at a time when individuals are at a higher risk for transmitting the virus.

  14. Exercise and Human Immunodeficiency Virus (HIV-1) Infection

    Science.gov (United States)

    Lawless, DeSales; Jackson, Catherine G. R.; Greenleaf, John E.

    1995-01-01

    The human immune system is highly efficient and remarkably protective when functioning properly. Similar to other physiological systems, it functions best when the body is maintained with a balanced diet, sufficient rest and a moderately stress-free lifestyle. It can be disrupted by inappropriate drug use and extreme emotion or exertion. The functioning of normal or compromised immune systems can be enhanced by properly prescribed moderate exercise conditioning regimens in healthy people, and in some human immunodeficiency virus (HIV-1)-infected patients but not in others who unable to complete an interval training program. Regular exercise conditioning in healthy people reduces cardiovascular risk factors, increases stamina, facilitates bodyweight control, and reduces stress by engendering positive feelings of well-being. Certain types of cancer may also be suppressed by appropriate exercise conditioning. Various exercise regimens are being evaluated as adjunct treatments for medicated patients with the HIV-1 syndrome. Limited anecdotal evidence from patients suggests that moderate exercise conditioning is per se responsible for their survival well beyond expectancy. HIV-1-infected patients respond positively, both physiologically and psychologically, to moderate exercise conditioning. However, the effectiveness of any exercise treatment programme depends on its mode, frequency, intensity and duration when prescribed o complement the pathological condition of the patient. The effectiveness of exercise conditioning regimens in patients with HIV-1 infection is reviewed in this article. In addition, we discuss mechanisms and pathways, involving the interplay of psychological and physiological factors, through which the suppressed immune system can be enhanced. The immune modulators discussed are endogenous opioids, cytokines, neurotransmitters and other hormones. Exercise conditioning treatment appears to be more effective when combined with other stress management

  15. Epsilon substituted lysinol derivatives as HIV-1 protease inhibitors.

    Science.gov (United States)

    Jones, Kristen L G; Holloway, M Katharine; Su, Hua-Poo; Carroll, Steven S; Burlein, Christine; Touch, Sinoeun; DiStefano, Daniel J; Sanchez, Rosa I; Williams, Theresa M; Vacca, Joseph P; Coburn, Craig A

    2010-07-15

    A series of HIV-1 protease inhibitors containing an epsilon substituted lysinol backbone was synthesized. Two novel synthetic routes using N-boc-L-glutamic acid alpha-benzyl ester and 2,6-diaminopimelic acid were developed. Incorporation of this epsilon substituent enabled access to the S2 pocket of the enzyme, affording high potency inhibitors. Modeling studies and synthetic efforts suggest the potency increase is due to both conformational bias and van der Waals interactions with the S2 pocket.

  16. HIV-1 binding and neutralizing antibodies of injecting drug users

    Directory of Open Access Journals (Sweden)

    Ouverney E.P.

    2005-01-01

    Full Text Available Previous studies have demonstrated a stronger seroreactivity against some synthetic peptides responsible for inducing neutralizing antibodies in injecting drug users (IDU compared to that of individuals sexually infected with HIV-1 (S, but the effectiveness in terms of the neutralizing ability of these antibodies has not been evaluated. Our objective was to study the humoral immune response of IDU by determining the specificity of their antibodies and the presence of neutralizing antibodies. The neutralization capacity against the HIV-1 isolate MN (genotype B, the primary HIV-1 isolate 95BRRJ021 (genotype F, and the seroreactivity with peptides known to induce neutralizing antibodies, from the V2 and V3 loops of different HIV-1 subtypes, were analyzed. Seroreactivity indicates that IDU plasma are more likely to recognize a broader range of peptides than S plasma, with significantly higher titers, especially of V3 peptides. Similar neutralization frequencies of the MN isolate were observed in plasma of the IDU (16/47 and S (20/60 groups in the 1:10 dilution. The neutralization of the 95BRRJ021 isolate was more frequently observed for plasma from the S group (15/23 than from the IDU group (15/47, P = 0.0108. No correlation between neutralization and seroreactivity with the peptides tested was observed. These results suggest that an important factor responsible for the extensive and broad humoral immune response observed in IDU is their infection route. There was very little difference in neutralizing antibody response between the IDU and S groups despite their differences in seroreactivity and health status.

  17. Recent Progress toward Engineering HIV-1-Specific Neutralizing Monoclonal Antibodies

    OpenAIRE

    Ming Sun; Yue Li; Huiwen Zheng; Yiming Shao

    2016-01-01

    The recent discoveries of broadly potent neutralizing human monoclonal antibodies represent a new generation of antiretrovirals for the treatment and prophylaxis. Antibodies are generally considered more effective and safer and have been proved to provide passive protection against mucosal challenge in humanized mice and macaques. Several neutralizing Abs could protect animals against HIV-1 but are not effective when used in an established infected model for therapy. In order to overcome the ...

  18. Thymic plasmacytoid dendritic cells are susceptible to productive HIV-1 infection and efficiently transfer R5 HIV-1 to thymocytes in vitro

    Directory of Open Access Journals (Sweden)

    Wright Edwina

    2011-06-01

    Full Text Available Abstract Background HIV-1 infection of the thymus contributes to the defective regeneration and loss of CD4+ T cells in HIV-1-infected individuals. As thymic dendritic cells (DC are permissive to infection by HIV-1, we examined the ability of thymic DC to enhance infection of thymocytes which may contribute to the overall depletion of CD4+ T cells. We compared productive infection in isolated human thymic and blood CD11c+ myeloid DC (mDC and CD123+ plasmacytoid DC (pDC using enhanced green fluorescent protein (EGFP CCR5 (R5-tropic NL(AD8 and CXCR4 (X4-tropic NL4-3 HIV-1 reporter viruses. Transfer of productive HIV-1 infection from thymic mDC and pDC was determined by culturing these DC subsets either alone or with sorted thymocytes. Results Productive infection was observed in both thymic pDC and mDC following exposure to R5 HIV-1 and X4 HIV-1. Thymic pDC were more frequently productively infected by both R5 and X4 HIV-1 than thymic mDC (p = 0.03; n = 6. Thymic pDC efficiently transferred productive R5 HIV-1 infection to both CD3hi (p = 0.01; mean fold increase of 6.5; n = 6 and CD3lo thymocytes (mean fold increase of 1.6; n = 2. In comparison, transfer of productive infection by thymic mDC was not observed for either X4 or R5 HIV-1. Conclusions The capacity of thymic pDC to efficiently transfer R5 HIV-1 to both mature and immature thymocytes that are otherwise refractory to R5 virus may represent a pathway to early infection and impaired production of thymocytes and CD4+ T cells in HIV-1-infected individuals.

  19. Rapid Antiretroviral Therapy Initiation for Women in an HIV-1 Prevention Clinical Trial Experiencing Primary HIV-1 Infection during Pregnancy or Breastfeeding.

    Directory of Open Access Journals (Sweden)

    Susan Morrison

    Full Text Available During an HIV-1 prevention clinical trial in East Africa, we observed 16 cases of primary HIV-1 infection in women coincident with pregnancy or breastfeeding. Nine of eleven pregnant women initiated rapid combination antiretroviral therapy (ART, despite having CD4 counts exceeding national criteria for ART initiation; breastfeeding women initiated ART or replacement feeding. Rapid ART initiation during primary HIV-1 infection during pregnancy and breastfeeding is feasible in this setting.

  20. Mother-to-Child HIV-1 Transmission Events Are Differentially Impacted by Breast Milk and Its Components from HIV-1-Infected Women.

    Directory of Open Access Journals (Sweden)

    Ruizhong Shen

    Full Text Available Breast milk is a vehicle of infection and source of protection in post-natal mother-to-child HIV-1 transmission (MTCT. Understanding the mechanism by which breast milk limits vertical transmission will provide critical insight into the design of preventive and therapeutic approaches to interrupt HIV-1 mucosal transmission. However, characterization of the inhibitory activity of breast milk in human intestinal mucosa, the portal of entry in postnatal MTCT, has been constrained by the limited availability of primary mucosal target cells and tissues to recapitulate mucosal transmission ex vivo. Here, we characterized the impact of skimmed breast milk, breast milk antibodies (Igs and non-Ig components from HIV-1-infected Ugandan women on the major events of HIV-1 mucosal transmission using primary human intestinal cells and tissues. HIV-1-specific IgG antibodies and non-Ig components in breast milk inhibited the uptake of Ugandan HIV-1 isolates by primary human intestinal epithelial cells, viral replication in and transport of HIV-1- bearing dendritic cells through the human intestinal mucosa. Breast milk HIV-1-specific IgG and IgA, as well as innate factors, blocked the uptake and transport of HIV-1 through intestinal mucosa. Thus, breast milk components have distinct and complementary effects in reducing HIV-1 uptake, transport through and replication in the intestinal mucosa and, therefore, likely contribute to preventing postnatal HIV-1 transmission. Our data suggests that a successful preventive or therapeutic approach would require multiple immune factors acting at multiple steps in the HIV-1 mucosal transmission process.

  1. Structure and dynamics of the HIV-1 frameshift element RNA.

    Science.gov (United States)

    Low, Justin T; Garcia-Miranda, Pablo; Mouzakis, Kathryn D; Gorelick, Robert J; Butcher, Samuel E; Weeks, Kevin M

    2014-07-08

    The HIV-1 ribosomal frameshift element is highly structured, regulates translation of all virally encoded enzymes, and is a promising therapeutic target. The prior model for this motif contains two helices separated by a three-nucleotide bulge. Modifications to this model were suggested by SHAPE chemical probing of an entire HIV-1 RNA genome. Novel features of the SHAPE-directed model include alternate helical conformations and a larger, more complex structure. These structural elements also support the presence of a secondary frameshift site within the frameshift domain. Here, we use oligonucleotide-directed structure perturbation, probing in the presence of formamide, and in-virion experiments to examine these models. Our data support a model in which the frameshift domain is anchored by a stable helix outside the conventional domain. Less stable helices within the domain can switch from the SHAPE-predicted to the two-helix conformation. Translational frameshifting assays with frameshift domain mutants support a functional role for the interactions predicted by and specific to the SHAPE-directed model. These results reveal that the HIV-1 frameshift domain is a complex, dynamic structure and underscore the importance of analyzing folding in the context of full-length RNAs.

  2. Positron emission tomography in patients suffering from HIV-1 infection

    Energy Technology Data Exchange (ETDEWEB)

    Sathekge, Mike [University Hospital of Pretoria, Department of Nuclear Medicine, Pretoria (South Africa); Goethals, Ingeborg; Wiele, Christophe van de [University Hospital Ghent, Department of Nuclear Medicine, Ghent (Belgium); Maes, Alex [AZ Groening, Department of Nuclear Medicine, Kortrijk (Belgium)

    2009-07-15

    This paper reviews currently available PET studies performed either to improve our understanding of the pathogenesis of HIV-1 infection or to assess the value of PET imaging in the clinical decision making of patients infected with HIV-1 presenting with AIDS-related opportunistic infections and malignancies. FDG PET has shown that HIV-1 infection progresses by distinct anatomical steps, with involvement of the upper torso preceding involvement of the lower part of the torso, and that the degree of FDG uptake relates to viral load. The former finding suggests that lymphoid tissues are engaged in a predictable sequence and that diffusible mediators of activation might be important targets for vaccine or therapeutic intervention strategies. In lipodystrophic HIV-infected patients, limited available data support the hypothesis that stavudine-related lipodystrophy is associated with increased glucose uptake by adipose tissue as a result of the metabolic stress of adipose tissue in response to highly active antiretroviral treatment (HAART). Finally, in early AIDS-related dementia complex (ADC), striatal hypermetabolism is observed, whereas progressive ADC is characterized by a decrease in subcortical and cortical metabolism. In the clinical setting, PET has been shown to allow the differentiation of AIDS-related opportunistic infections and malignancies, and to allow monitoring of side effects of HAART. However, in patients suffering from HIV infection and presenting with extracerebral lymphoma or other human malignancies, knowledge of viraemia is essential when interpreting FDG PET imaging. (orig.)

  3. Innate immune activation in primary HIV-1 infection.

    Science.gov (United States)

    Chang, J Judy; Altfeld, Marcus

    2010-10-15

    There is growing evidence that highlights the role of the immune response during acute human immunodeficiency virus type 1 (HIV-1) infection in the control or development of disease. The adaptive immune responses do not appear until after HIV-1 infection is already well established, so the role of earlier and faster-responding innate immunity needs to be more closely scrutinized. In particular, 2 aspects of innate immunity for which there are growing research developments will be examined in this review: the actions of type I interferons and natural killer cells. These two components of the innate immune response contribute to viral control both by killing infected cells and by modulating other immune cells that develop. However, the role of interferon α in immune activation is a double-edged sword, causing recruitment of adaptive immune cells that can assist in viral control but concurrently contributing to immune activation-dependent disease progression. Understanding the complexity of how innate responses affect the outcome of HIV-1 infection will help in the development of vaccines that can use innate immunity to enhance viral control with minimal pathogenesis.

  4. Copy number variation of KIR genes influences HIV-1 control

    DEFF Research Database (Denmark)

    Pelak, Kimberly; Need, Anna C; Fellay, Jacques;

    2011-01-01

    A genome-wide screen for large structural variants showed that a copy number variant (CNV) in the region encoding killer cell immunoglobulin-like receptors (KIR) associates with HIV-1 control as measured by plasma viral load at set point in individuals of European ancestry. This CNV encompasses...... the KIR3DL1-KIR3DS1 locus, encoding receptors that interact with specific HLA-Bw4 molecules to regulate the activation of lymphocyte subsets including natural killer (NK) cells. We quantified the number of copies of KIR3DS1 and KIR3DL1 in a large HIV-1 positive cohort, and showed that an increase in KIR3...... individuals with multiple copies of KIR3DL1, in the presence of KIR3DS1 and the appropriate ligands, inhibit HIV-1 replication more robustly, and associated with a significant expansion in the frequency of KIR3DS1+, but not KIR3DL1+, NK cells in their peripheral blood. Our results suggest that the relative...

  5. Oligodendrocyte Injury and Pathogenesis of HIV-1-Associated Neurocognitive Disorders

    Directory of Open Access Journals (Sweden)

    Han Liu

    2016-07-01

    Full Text Available Oligodendrocytes wrap neuronal axons to form myelin, an insulating sheath which is essential for nervous impulse conduction along axons. Axonal myelination is highly regulated by neuronal and astrocytic signals and the maintenance of myelin sheaths is a very complex process. Oligodendrocyte damage can cause axonal demyelination and neuronal injury, leading to neurological disorders. Demyelination in the cerebrum may produce cognitive impairment in a variety of neurological disorders, including human immunodeficiency virus type one (HIV-1-associated neurocognitive disorders (HAND. Although the combined antiretroviral therapy has markedly reduced the incidence of HIV-1-associated dementia, a severe form of HAND, milder forms of HAND remain prevalent even when the peripheral viral load is well controlled. HAND manifests as a subcortical dementia with damage in the brain white matter (e.g., corpus callosum, which consists of myelinated axonal fibers. How HIV-1 brain infection causes myelin injury and resultant white matter damage is an interesting area of current HIV research. In this review, we tentatively address recent progress on oligodendrocyte dysregulation and HAND pathogenesis.

  6. Aptamer-targeted RNAi for HIV-1 therapy.

    Science.gov (United States)

    Zhou, Jiehua; Rossi, John J

    2011-01-01

    The highly specific mechanism of RNA (RNAi) that inhibits the expression of disease genes is increasingly being harnessed to develop a new class of therapeutics for a wide variety of human maladies. The successful use of small interfering RNAs (siRNAs) for therapeutic purposes requires safe and efficient delivery to specific cells and tissues. Herein, we demonstrate novel cell type-specific dual inhibitory function anti-gp120 aptamer-siRNA delivery systems for HIV-1 therapy, in which both the aptamer and the siRNA portions have potent anti-HIV activities. The envelope glycoprotein is expressed on the surface of HIV-1 infected cells, allowing binding and internalization of the aptamer-siRNA chimeric molecules. The Dicer substrate siRNA delivered by the aptamers is functionally processed by Dicer, resulting in specific inhibition of HIV-1 replication and infectivity in cultured CEM T-cells and primary blood mononuclear cells. Our results provide a set of novel aptamer-targeted RNAi therapeutics to combat HIV and further validate the use of anti-gp120 aptamers for delivery of Dicer substrate siRNAs.

  7. Oligodendrocyte Injury and Pathogenesis of HIV-1-Associated Neurocognitive Disorders

    Science.gov (United States)

    Liu, Han; Xu, Enquan; Liu, Jianuo; Xiong, Huangui

    2016-01-01

    Oligodendrocytes wrap neuronal axons to form myelin, an insulating sheath which is essential for nervous impulse conduction along axons. Axonal myelination is highly regulated by neuronal and astrocytic signals and the maintenance of myelin sheaths is a very complex process. Oligodendrocyte damage can cause axonal demyelination and neuronal injury, leading to neurological disorders. Demyelination in the cerebrum may produce cognitive impairment in a variety of neurological disorders, including human immunodeficiency virus type one (HIV-1)-associated neurocognitive disorders (HAND). Although the combined antiretroviral therapy has markedly reduced the incidence of HIV-1-associated dementia, a severe form of HAND, milder forms of HAND remain prevalent even when the peripheral viral load is well controlled. HAND manifests as a subcortical dementia with damage in the brain white matter (e.g., corpus callosum), which consists of myelinated axonal fibers. How HIV-1 brain infection causes myelin injury and resultant white matter damage is an interesting area of current HIV research. In this review, we tentatively address recent progress on oligodendrocyte dysregulation and HAND pathogenesis. PMID:27455335

  8. Complement-Opsonized HIV-1 Overcomes Restriction in Dendritic Cells.

    Directory of Open Access Journals (Sweden)

    Wilfried Posch

    2015-06-01

    Full Text Available DCs express intrinsic cellular defense mechanisms to specifically inhibit HIV-1 replication. Thus, DCs are productively infected only at very low levels with HIV-1, and this non-permissiveness of DCs is suggested to go along with viral evasion. We now illustrate that complement-opsonized HIV-1 (HIV-C efficiently bypasses SAMHD1 restriction and productively infects DCs including BDCA-1 DCs. Efficient DC infection by HIV-C was also observed using single-cycle HIV-C, and correlated with a remarkable elevated SAMHD1 T592 phosphorylation but not SAMHD1 degradation. If SAMHD1 phosphorylation was blocked using a CDK2-inhibitor HIV-C-induced DC infection was also significantly abrogated. Additionally, we found a higher maturation and co-stimulatory potential, aberrant type I interferon expression and signaling as well as a stronger induction of cellular immune responses in HIV-C-treated DCs. Collectively, our data highlight a novel protective mechanism mediated by complement opsonization of HIV to effectively promote DC immune functions, which might be in the future exploited to tackle HIV infection.

  9. Developments of indoles as anti-HIV-1 inhibitors.

    Science.gov (United States)

    Xu, Hui; Lv, Min

    2009-01-01

    Since the first case of acquired immunodeficiency syndrome (AIDS) was reported in 1981, AIDS has always been a global health threat and the leading cause of deaths due to the rapid emergence of drug-resistance and unwanted metabolic side effects. Every day in 2007 an estimated 6850 people were newly infected with human immunodeficiency virus (HIV). Over the past 28 years the rapid worldwide spread of AIDS has prompted an intense research effort to discover compounds that could effectively inhibit HIV. The development of new, selective and safe inhibitors for the treatment of HIV, therefore, still remains a high priority for medical research. To the best of our knowledge, the indole derivatives have been considered as one class of promising HIV-1 inhibitors, such as delavirdine approved by the Food and Drug Administration (FDA) in 1997 for use in combination with other antiretrovirals in adults with HIV infection. In this review we focus on the synthesis and anti-HIV-1 activity of indole derivatives, in the meantime, the structure-activity relationship (SAR) for some derivatives are also surveyed. It will pave the way for the design of indole derivatives as anti-HIV-1 drugs in the future.

  10. TRIM5 and the Regulation of HIV-1 Infectivity

    Directory of Open Access Journals (Sweden)

    Jeremy Luban

    2012-01-01

    Full Text Available The past ten years have seen an explosion of information concerning host restriction factors that inhibit the replication of HIV-1 and other retroviruses. Among these factors is TRIM5, an innate immune signaling molecule that recognizes the capsid lattice as soon as the retrovirion core is released into the cytoplasm of otherwise susceptible target cells. Recognition of the capsid lattice has several consequences that include multimerization of TRIM5 into a complementary lattice, premature uncoating of the virion core, and activation of TRIM5 E3 ubiquitin ligase activity. Unattached, K63-linked ubiquitin chains are generated that activate the TAK1 kinase complex and downstream inflammatory mediators. Polymorphisms in the capsid recognition domain of TRIM5 explain the observed species-specific differences among orthologues and the relatively weak anti-HIV-1 activity of human TRIM5. Better understanding of the complex interaction between TRIM5 and the retrovirus capsid lattice may someday lead to exploitation of this interaction for the development of potent HIV-1 inhibitors.

  11. The HIV-1 Envelope Transmembrane Domain Binds TLR2 through a Distinct Dimerization Motif and Inhibits TLR2-Mediated Responses

    Science.gov (United States)

    Rotem, Etai; Schwarzter, Roland; Gramatica, Andrea; Futerman, Anthony H.; Shai, Yechiel

    2014-01-01

    HIV-1 uses a number of means to manipulate the immune system, to avoid recognition and to highjack signaling pathways. HIV-1 infected cells show limited Toll-Like Receptor (TLR) responsiveness via as yet unknown mechanisms. Using biochemical and biophysical approaches, we demonstrate that the trans-membrane domain (TMD) of the HIV-1 envelope (ENV) directly interacts with TLR2 TMD within the membrane milieu. This interaction attenuates TNFα, IL-6 and MCP-1 secretion in macrophages, induced by natural ligands of TLR2 both in in vitro and in vivo models. This was associated with decreased levels of ERK phosphorylation. Furthermore, mutagenesis demonstrated the importance of a conserved GxxxG motif in driving this interaction within the membrane milieu. The administration of the ENV TMD in vivo to lipotechoic acid (LTA)/Galactosamine-mediated septic mice resulted in a significant decrease in mortality and in tissue damage, due to the weakening of systemic macrophage activation. Our findings suggest that the TMD of ENV is involved in modulation of the innate immune response during HIV infection. Furthermore, due to the high functional homology of viral ENV proteins this function may be a general character of viral-induced immune modulation. PMID:25121610

  12. The HIV-1 envelope transmembrane domain binds TLR2 through a distinct dimerization motif and inhibits TLR2-mediated responses.

    Science.gov (United States)

    Reuven, Eliran Moshe; Ali, Mohammad; Rotem, Etai; Schwarzer, Roland; Schwarzter, Roland; Gramatica, Andrea; Futerman, Anthony H; Shai, Yechiel

    2014-08-01

    HIV-1 uses a number of means to manipulate the immune system, to avoid recognition and to highjack signaling pathways. HIV-1 infected cells show limited Toll-Like Receptor (TLR) responsiveness via as yet unknown mechanisms. Using biochemical and biophysical approaches, we demonstrate that the trans-membrane domain (TMD) of the HIV-1 envelope (ENV) directly interacts with TLR2 TMD within the membrane milieu. This interaction attenuates TNFα, IL-6 and MCP-1 secretion in macrophages, induced by natural ligands of TLR2 both in in vitro and in vivo models. This was associated with decreased levels of ERK phosphorylation. Furthermore, mutagenesis demonstrated the importance of a conserved GxxxG motif in driving this interaction within the membrane milieu. The administration of the ENV TMD in vivo to lipotechoic acid (LTA)/Galactosamine-mediated septic mice resulted in a significant decrease in mortality and in tissue damage, due to the weakening of systemic macrophage activation. Our findings suggest that the TMD of ENV is involved in modulation of the innate immune response during HIV infection. Furthermore, due to the high functional homology of viral ENV proteins this function may be a general character of viral-induced immune modulation.

  13. The HIV-1 envelope transmembrane domain binds TLR2 through a distinct dimerization motif and inhibits TLR2-mediated responses.

    Directory of Open Access Journals (Sweden)

    Eliran Moshe Reuven

    2014-08-01

    Full Text Available HIV-1 uses a number of means to manipulate the immune system, to avoid recognition and to highjack signaling pathways. HIV-1 infected cells show limited Toll-Like Receptor (TLR responsiveness via as yet unknown mechanisms. Using biochemical and biophysical approaches, we demonstrate that the trans-membrane domain (TMD of the HIV-1 envelope (ENV directly interacts with TLR2 TMD within the membrane milieu. This interaction attenuates TNFα, IL-6 and MCP-1 secretion in macrophages, induced by natural ligands of TLR2 both in in vitro and in vivo models. This was associated with decreased levels of ERK phosphorylation. Furthermore, mutagenesis demonstrated the importance of a conserved GxxxG motif in driving this interaction within the membrane milieu. The administration of the ENV TMD in vivo to lipotechoic acid (LTA/Galactosamine-mediated septic mice resulted in a significant decrease in mortality and in tissue damage, due to the weakening of systemic macrophage activation. Our findings suggest that the TMD of ENV is involved in modulation of the innate immune response during HIV infection. Furthermore, due to the high functional homology of viral ENV proteins this function may be a general character of viral-induced immune modulation.

  14. Translational regulation of HIV-1 replication by HIV-1 Rev cellular cofactors Sam68, eIF5A, hRIP, and DDX3.

    Science.gov (United States)

    Liu, Jinfeng; Henao-Mejia, Jorge; Liu, Hao; Zhao, Yingren; He, Johnny J

    2011-06-01

    Nuclear export and translation of HIV-1 RNA are two important posttranscriptional events for HIV-1 gene expression and replication. HIV-1 Rev functions to export unspliced and incompletely spliced HIV-1 RNA from the nucleus to the cytoplasm; it requires interaction with several cellular cofactors such as Sam68, eIF5A, hRIP, and DDX3. Meanwhile, some studies have also implicated Rev and some of its cofactors such as Sam68 in HIV-1 RNA translation. Thus, in this study, we aimed to characterize the potential function of all these four Rev cofactors in HIV-1 RNA translation. Ectopic expression, siRNA knockdown, and trans-complementation assays confirmed that all these cofactors were very important for HIV-1 gene expression and production through Rev and, accordingly, Rev-dependent reporter gene expression. Importantly, these studies revealed for the first time that each of these cofactors also regulated Rev-independent reporter gene expression. To directly determine the roles of these cofactors in HIV-1 RNA translation, we designed and synthesized a full-length capped HIV-1 RNA in vitro, transfected it into cells to bypass the RNA nuclear export step, and determined HIV-1 Gag expression from the cytoplasmic RNA in the cells that had ectopically expressed or siRNA knocked down cofactors. Gag expression was found to closely correlate with the expression levels of all these cofactors. Furthermore, we took advantage of a HIV-1 internal ribosomal entry site (IRES)-based bicistronic reporter gene assay and determined the effects of these cofactors on cap-independent IRES-mediated HIV-1 translation. The results showed that DDX3, eIF5A, and hRIP enhanced HIV-1 IRES-mediated translation, whereas Sam68 did not. Taken together, these results show that HIV-1 Rev cofactors Sam68, eIF5A, hRIP, and DDX3 also function in the translation of HIV-1 RNA and suggest that the regulatory mechanisms of HIV-1 RNA translation are likely different among these cofactors.

  15. HIV-1-infected and immune-activated macrophages induce astrocytic differentiation of human cortical neural progenitor cells via the STAT3 pathway.

    Directory of Open Access Journals (Sweden)

    Hui Peng

    Full Text Available Diminished adult neurogenesis is considered a potential mechanism in the pathogenesis of HIV-1-associated dementia (HAD. In HAD, HIV-1-infected and immune-activated brain mononuclear phagocytes (MP; perivascular macrophages and microglia drive central nervous system (CNS inflammation and may alter normal neurogenesis. We previously demonstrated HIV-1-infected and lipopolysaccharide (LPS activated monocyte-derived macrophages (MDM inhibit human neural progenitor cell (NPC neurogenesis, while enhancing astrogliogenesis through the secretion of the inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α, in vitro and in vivo. Here we further test the hypothesis that HIV-1-infected/activated MDM promote NPC astrogliogenesis via activation of the transcription factor signal transducer and activator of transcription 3 (STAT3, a critical factor for astrogliogenesis. Our results show that LPS-activated MDM-conditioned medium (LPS-MCM and HIV-infected/LPS-activated MDM-conditioned medium (LPS+HIV-MCM induced Janus kinase 1 (Jak1 and STAT3 activation. Induction of the Jak-STAT3 activation correlated with increased glia fibrillary acidic protein (GFAP expression, demonstrating an induction of astrogliogenesis. Moreover, STAT3-targeting siRNA (siSTAT3 decreased MCM-induced STAT3 activation and NPC astrogliogenesis. Furthermore, inflammatory cytokines (including IL-6, IL-1β and TNF-α produced by LPS-activated and/or HIV-1-infected MDM may contribute to MCM-induced STAT3 activation and astrocytic differentiation. These observations were confirmed in severe combined immunodeficient (SCID mice with HIV-1 encephalitis (HIVE. In HIVE mice, siRNA control (without target sequence, sicon pre-transfected NPCs injected with HIV-1-infected MDM showed more astrocytic differentiation and less neuronal differentiation of NPCs as compared to NPC injection alone. siSTAT3 abrogated HIV-1-infected MDM-induced astrogliogenesis of injected NPCs. Collectively, these

  16. Therapeutic doses of irradiation activate viral transcription and induce apoptosis in HIV-1 infected cells

    Energy Technology Data Exchange (ETDEWEB)

    Iordanskiy, Sergey [School of Systems Biology, Laboratory of Molecular Virology, George Mason University, Manassas, VA 20110 (United States); Van Duyne, Rachel [School of Systems Biology, Laboratory of Molecular Virology, George Mason University, Manassas, VA 20110 (United States); Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702 (United States); Sampey, Gavin C; Woodson, Caitlin M; Fry, Kelsi; Saifuddin, Mohammed; Guo, Jia; Wu, Yuntao [School of Systems Biology, Laboratory of Molecular Virology, George Mason University, Manassas, VA 20110 (United States); Romerio, Fabio [Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201 (United States); Kashanchi, Fatah, E-mail: fkashanc@gmu.edu [School of Systems Biology, Laboratory of Molecular Virology, George Mason University, Manassas, VA 20110 (United States)

    2015-11-15

    The highly active antiretroviral therapy reduces HIV-1 RNA in plasma to undetectable levels. However, the virus continues to persist in the long-lived resting CD4{sup +} T cells, macrophages and astrocytes which form a viral reservoir in infected individuals. Reactivation of viral transcription is critical since the host immune response in combination with antiretroviral therapy may eradicate the virus. Using the chronically HIV-1 infected T lymphoblastoid and monocytic cell lines, primary quiescent CD4{sup +} T cells and humanized mice infected with dual-tropic HIV-1 89.6, we examined the effect of various X-ray irradiation (IR) doses (used for HIV-related lymphoma treatment and lower doses) on HIV-1 transcription and viability of infected cells. Treatment of both T cells and monocytes with IR, a well-defined stress signal, led to increase of HIV-1 transcription, as evidenced by the presence of RNA polymerase II and reduction of HDAC1 and methyl transferase SUV39H1 on the HIV-1 promoter. This correlated with the increased GFP signal and elevated level of intracellular HIV-1 RNA in the IR-treated quiescent CD4{sup +} T cells infected with GFP-encoding HIV-1. Exposition of latently HIV-1infected monocytes treated with PKC agonist bryostatin 1 to IR enhanced transcription activation effect of this latency-reversing agent. Increased HIV-1 replication after IR correlated with higher cell death: the level of phosphorylated Ser46 in p53, responsible for apoptosis induction, was markedly higher in the HIV-1 infected cells following IR treatment. Exposure of HIV-1 infected humanized mice with undetectable viral RNA level to IR resulted in a significant increase of HIV-1 RNA in plasma, lung and brain tissues. Collectively, these data point to the use of low to moderate dose of IR alone or in combination with HIV-1 transcription activators as a potential application for the “Shock and Kill” strategy for latently HIV-1 infected cells. - Highlights: • X-ray irradiation

  17. Inhibition of reverse transcriptase activity increases stability of the HIV-1 core.

    Science.gov (United States)

    Yang, Yang; Fricke, Thomas; Diaz-Griffero, Felipe

    2013-01-01

    Previous studies showed that HIV-1 reverse transcription occurs during or before uncoating, linking mechanistically reverse transcription with uncoating. Here we show that inhibition of reverse transcriptase (RT) during HIV-1 infection by pharmacologic or genetic means increased the stability of the HIV-1 core during infection. Interestingly, HIV-1 particles with increased core stability were resistant to the core-destabilizing effects of rhesus TRIM5α (TRIM5α(rh)). Collectively, this work implies that the surface of the HIV-1 core is dynamic and changes upon the ongoing processes within the core.

  18. Focus on Chirality of HIV-1 Non-Nucleoside Reverse Transcriptase Inhibitors

    Directory of Open Access Journals (Sweden)

    Valeria Famiglini

    2016-02-01

    Full Text Available Chiral HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs are of great interest since one enantiomer is often more potent than the corresponding counterpart against the HIV-1 wild type (WT and the HIV-1 drug resistant mutant strains. This review exemplifies the various studies made to investigate the effect of chirality on the antiretroviral activity of top HIV-1 NNRTI compounds, such as nevirapine (NVP, efavirenz (EFV, alkynyl- and alkenylquinazolinone DuPont compounds (DPC, diarylpyrimidine (DAPY, dihydroalkyloxybenzyloxopyrimidine (DABO, phenethylthiazolylthiourea (PETT, indolylarylsulfone (IAS, arylphosphoindole (API and trifluoromethylated indole (TFMI The chiral separation, the enantiosynthesis, along with the biological properties of these HIV-1 NNRTIs, are discussed.

  19. Prognostic value of a CCR5 defective allele in pediatric HIV-1 infection.

    OpenAIRE

    2000-01-01

    BACKGROUND: A deletion of 32 base pairs in the CCR5 gene (delta32 CCR5) has been linked to resistance to HIV-1 infection in exposed adults and to the delay of disease progression in infected adults. MATERIALS AND METHODS: To determine the role of delta32 CCR5 in disease progression of HIV-1 infected children born to seropositive mothers, we studied a polymerase chain reaction in 301 HIV-1 infected, 262 HIV-1 exposed-uninfected and 47 HIV-1 unexposed-uninfected children of Spanish and Italian ...

  20. HIV-1 transmission during early antiretroviral therapy: evaluation of two HIV-1 transmission events in the HPTN 052 prevention study.

    Directory of Open Access Journals (Sweden)

    Li-Hua Ping

    Full Text Available In the HPTN 052 study, transmission between HIV-discordant couples was reduced by 96% when the HIV-infected partner received suppressive antiretroviral therapy (ART. We examined two transmission events where the newly infected partner was diagnosed after the HIV-infected partner (index initiated therapy. We evaluated the sequence complexity of the viral populations and antibody reactivity in the newly infected partner to estimate the dates of transmission to the newly infected partners. In both cases, transmission most likely occurred significantly before HIV-1 diagnosis of the newly infected partner, and either just before the initiation of therapy or before viral replication was adequately suppressed by therapy of the index. This study further strengthens the conclusion about the efficacy of blocking transmission by treating the infected partner of discordant couples. However, this study does not rule out the potential for HIV-1 transmission to occur shortly after initiation of ART, and this should be recognized when antiretroviral therapy is used for HIV-1 prevention.

  1. HIV-1潜伏感染及功能性治愈%HIV-1 Latency and Functional Cure

    Institute of Scientific and Technical Information of China (English)

    杨福春; 李川; 王建华

    2015-01-01

    尽管高效抗反转录病毒治疗(HAART)可有效控制艾滋病(AIDS)病人体内的艾滋病病毒1型(HIV-1)的复制,但却无法根除潜伏感染的病毒,这成为当前艾滋病治疗的主要难点之一.研究HIV-1在宿主细胞内建立和维持潜伏的分子细胞学机制,有助于发现新的抗病毒靶点和发展新的抗病毒治疗策略.近年来对HIV感染者/AIDS病人提出功能性治愈策略,相关的免疫或基因治疗手段被相继提出,部分策略已处于临床试验阶段.该文对HIV-1潜伏感染机制和功能性治愈相关研究进展进行简要综述.

  2. Sargassum fusiforme fraction is a potent and specific inhibitor of HIV-1 fusion and reverse transcriptase

    Directory of Open Access Journals (Sweden)

    Thornber Carol

    2008-01-01

    Full Text Available Abstract Sargassum fusiforme (Harvey Setchell has been shown to be a highly effective inhibitor of HIV-1 infection. To identify its mechanism of action, we performed bioactivity-guided fractionation on Sargassum fusiforme mixture. Here, we report isolation of a bioactive fraction SP4-2 (S. fusiforme, which at 8 μg/ml inhibited HIV-1 infection by 86.9%, with IC50 value of 3.7 μg. That represents 230-fold enhancement of antiretroviral potency as compared to the whole extract. Inhibition was mediated against both CXCR4 (X4 and CCR5 (R5 tropic HIV-1. Specifically, 10 μg/ml SP4-2 blocked HIV-1 fusion and entry by 53%. This effect was reversed by interaction of SP4-2 with sCD4, suggesting that S. fusiforme inhibits HIV-1 infection by blocking CD4 receptor, which also explained observed inhibition of both X4 and R5-tropic HIV-1. SP4-2 also inhibited HIV-1 replication after virus entry, by directly inhibiting HIV-1 reverse transcriptase (RT in a dose dependent manner by up to 79%. We conclude that the SP4-2 fraction contains at least two distinct and biologically active molecules, one that inhibits HIV-1 fusion by interacting with CD4 receptor, and another that directly inhibits HIV-1 RT. We propose that S. fusiforme is a lead candidate for anti-HIV-1 drug development.

  3. Down-regulation of HIV-1 Infection by Inhibition of the MAPK Signaling Pathway

    Institute of Scientific and Technical Information of China (English)

    Jian Gong; Xi-hui Shen; Chao Chen; Hui Qiu; Rong-ge Yang

    2011-01-01

    The human immunodeficiency virus type 1(HIV-1)can interact with and exploit the host cellular machinery to replicate and propagate itself.Numerous studies have shown that the Mitogen-activated protein kinase(MAPK)signal pathway can positively regulate the replication of HIV-1,but exactly how each MAPK pathway affects HIV-1 infection and replication is not understood.In this study,we used the Extracellular signal-regulated kinase(ERK)pathway inhibitor,PD98059,the Jun N-terminal kinase(JNK)pathway inhibitor,SP600125,and the p38 pathway inhibitor,SB203580,to investigate the roles of these pathways in HIV-1replication.We found that application of PD98059 results in a strong VSV-G pseudotyped HIV-1NL4-3 luciferase reporter virus and HIV-1NL4-3 virus inhibition activity.In addition,SB203580 and SP600125 also elicited marked VSV-G pseudotyped HIV-1NL4-3 luciferase reporter virus inhibition activity but no HIV-1NL4-3 virus inhibition activity.We also found that SB203580 and SP600125 can enhance the HIV-1 inhibition activity of PD98059when cells were treated with all three MAPK pathway inhibitors in combination.Finally,we show that HIV-1virus inhibition activity of the MAPK pathway inhibitors was the result of the negative regulation of HIV-1 LTR promoter activity.

  4. Molecular recognition of CCR5 by an HIV-1 gp120 V3 loop.

    Science.gov (United States)

    Tamamis, Phanourios; Floudas, Christodoulos A

    2014-01-01

    The binding of protein HIV-1 gp120 to coreceptors CCR5 or CXCR4 is a key step of the HIV-1 entry to the host cell, and is predominantly mediated through the V3 loop fragment of HIV-1 gp120. In the present work, we delineate the molecular recognition of chemokine receptor CCR5 by a dual tropic HIV-1 gp120 V3 loop, using a comprehensive set of computational tools predominantly based on molecular dynamics simulations and free energy calculations. We report, what is to our knowledge, the first complete HIV-1 gp120 V3 loop : CCR5 complex structure, which includes the whole V3 loop and the N-terminus of CCR5, and exhibits exceptional agreement with previous experimental findings. The computationally derived structure sheds light into the functional role of HIV-1 gp120 V3 loop and CCR5 residues associated with the HIV-1 coreceptor activity, and provides insights into the HIV-1 coreceptor selectivity and the blocking mechanism of HIV-1 gp120 by maraviroc. By comparing the binding of the specific dual tropic HIV-1 gp120 V3 loop with CCR5 and CXCR4, we observe that the HIV-1 gp120 V3 loop residues 13-21, which include the tip, share nearly identical structural and energetic properties in complex with both coreceptors. This result paves the way for the design of dual CCR5/CXCR4 targeted peptides as novel potential anti-AIDS therapeutics.

  5. Sargassum fusiforme fraction is a potent and specific inhibitor of HIV-1 fusion and reverse transcriptase.

    Science.gov (United States)

    Paskaleva, Elena E; Lin, Xudong; Duus, Karen; McSharry, James J; Veille, Jean-Claude L; Thornber, Carol; Liu, Yanze; Lee, David Yu-Wei; Canki, Mario

    2008-01-15

    Sargassum fusiforme (Harvey) Setchell has been shown to be a highly effective inhibitor of HIV-1 infection. To identify its mechanism of action, we performed bioactivity-guided fractionation on Sargassum fusiforme mixture. Here, we report isolation of a bioactive fraction SP4-2 (S. fusiforme), which at 8 mug/ml inhibited HIV-1 infection by 86.9%, with IC50 value of 3.7 mug. That represents 230-fold enhancement of antiretroviral potency as compared to the whole extract. Inhibition was mediated against both CXCR4 (X4) and CCR5 (R5) tropic HIV-1. Specifically, 10 mug/ml SP4-2 blocked HIV-1 fusion and entry by 53%. This effect was reversed by interaction of SP4-2 with sCD4, suggesting that S. fusiforme inhibits HIV-1 infection by blocking CD4 receptor, which also explained observed inhibition of both X4 and R5-tropic HIV-1. SP4-2 also inhibited HIV-1 replication after virus entry, by directly inhibiting HIV-1 reverse transcriptase (RT) in a dose dependent manner by up to 79%. We conclude that the SP4-2 fraction contains at least two distinct and biologically active molecules, one that inhibits HIV-1 fusion by interacting with CD4 receptor, and another that directly inhibits HIV-1 RT. We propose that S. fusiforme is a lead candidate for anti-HIV-1 drug development.

  6. Multiple lysines combined in HIV-1 Vif determines the responsiveness to CBF-β.

    Science.gov (United States)

    Ai, Youwei; Ma, Jianzhang

    2015-02-13

    The Vif (viral infectivity factor) protein of human immunodeficiency virus type-1 (HIV-1) is critical for HIV-1 infectivity. CBF-β is required for HIV-1 Vif function, as it increases the steady-state level of the HIV-1 Vif protein to promote host restriction factor APOBEC3 degradation. However, the precise mechanism by which CBF-β promotes HIV-1 Vif levels remains unclear. In the present study, we provided evidences that CBF-β promoted steady-state levels of HIV-1 Vif by inhibiting the degradation of HIV-1 Vif through the proteasome pathway. Our results reveal a new mechanism by which a cellular protein supports viral infectivity by inhibiting viral protein degradation.

  7. HIV-1 RNAs are Not Part of the Argonaute 2 Associated RNA Interference Pathway in Macrophages.

    Directory of Open Access Journals (Sweden)

    Valentina Vongrad

    Full Text Available MiRNAs and other small noncoding RNAs (sncRNAs are key players in post-transcriptional gene regulation. HIV-1 derived small noncoding RNAs (sncRNAs have been described in HIV-1 infected cells, but their biological functions still remain to be elucidated. Here, we approached the question whether viral sncRNAs may play a role in the RNA interference (RNAi pathway or whether viral mRNAs are targeted by cellular miRNAs in human monocyte derived macrophages (MDM.The incorporation of viral sncRNAs and/or their target RNAs into RNA-induced silencing complex was investigated using photoactivatable ribonucleoside-induced cross-linking and immunoprecipitation (PAR-CLIP as well as high-throughput sequencing of RNA isolated by cross-linking immunoprecipitation (HITS-CLIP, which capture Argonaute2-bound miRNAs and their target RNAs. HIV-1 infected monocyte-derived macrophages (MDM were chosen as target cells, as they have previously been shown to express HIV-1 sncRNAs. In addition, we applied small RNA deep sequencing to study differential cellular miRNA expression in HIV-1 infected versus non-infected MDMs.PAR-CLIP and HITS-CLIP data demonstrated the absence of HIV-1 RNAs in Ago2-RISC, although the presence of a multitude of HIV-1 sncRNAs in HIV-1 infected MDMs was confirmed by small RNA sequencing. Small RNA sequencing revealed that 1.4% of all sncRNAs were of HIV-1 origin. However, neither HIV-1 derived sncRNAs nor putative HIV-1 target sequences incorporated into Ago2-RISC were identified suggesting that HIV-1 sncRNAs are not involved in the canonical RNAi pathway nor is HIV-1 targeted by this pathway in HIV-1 infected macrophages.

  8. Increased iron export by ferroportin induces restriction of HIV-1 infection in sickle cell disease

    Science.gov (United States)

    Kumari, Namita; Ammosova, Tatiana; Diaz, Sharmin; Lin, Xionghao; Niu, Xiaomei; Ivanov, Andrey; Jerebtsova, Marina; Dhawan, Subhash; Oneal, Patricia; Nekhai, Sergei

    2017-01-01

    The low incidence of HIV-1 infection in patients with sickle cell disease (SCD) and inhibition of HIV-1 replication in vitro under the conditions of low intracellular iron or heme treatment suggests a potential restriction of HIV-1 infection in SCD. We investigated HIV-1 ex vivo infection of SCD peripheral blood mononuclear cells (PBMCs) and found that HIV-1 replication was inhibited at the level of reverse transcription (RT) and transcription. We observed increased expression of heme and iron-regulated genes, previously shown to inhibit HIV-1, including ferroportin, IKBα, HO-1, p21, and SAM domain and HD domain-containing protein 1 (SAMHD1). HIV-1 inhibition was less pronounced in hepcidin-treated SCD PBMCs and more pronounced in the iron or iron chelators treated, suggesting a key role of iron metabolism. In SCD PBMCs, labile iron levels were reduced and protein levels of ferroportin, HIF-1α, IKBα, and HO-1 were increased. Hemin treatment induced ferroportin expression and inhibited HIV-1 in THP-1 cells, mimicking the HIV-1 inhibition in SCD PBMCs, especially as hepcidin similarly prevented HIV-1 inhibition. In THP-1 cells with knocked down ferroportin, IKBα, or HO-1 genes but not HIF-1α or p21, HIV-1 was not inhibited by hemin. Activity of SAMHD1-regulatory CDK2 was decreased, and SAMHD1 phosphorylation was reduced in SCD PBMCs and hemin-treated THP-1 cells, suggesting SAMHD1-mediated HIV-1 restriction in SCD. Our findings point to ferroportin as a trigger of HIV-1 restriction in SCD settings, linking reduced intracellular iron levels to the inhibition of CDK2 activity, reduction of SAMHD1 phosphorylation, increased IKBα expression, and inhibition of HIV-1 RT and transcription.

  9. Cocaine enhances HIV-1-induced CD4(+) T-cell apoptosis: implications in disease progression in cocaine-abusing HIV-1 patients.

    Science.gov (United States)

    Pandhare, Jui; Addai, Amma B; Mantri, Chinmay K; Hager, Cynthia; Smith, Rita M; Barnett, Louis; Villalta, Fernando; Kalams, Spyros A; Dash, Chandravanu

    2014-04-01

    Substance abuse is a major barrier in eradication of the HIV epidemic because it serves as a powerful cofactor for viral transmission, disease progression, and AIDS-related mortality. Cocaine, one of the commonly abused drugs among HIV-1 patients, has been suggested to accelerate HIV disease progression. However, the underlying mechanism remains largely unknown. Therefore, we tested whether cocaine augments HIV-1-associated CD4(+) T-cell decline, a predictor of HIV disease progression. We examined apoptosis of resting CD4(+) T cells from HIV-1-negative and HIV-1-positive donors in our study, because decline of uninfected cells plays a major role in HIV-1 disease progression. Treatment of resting CD4(+) T cells with cocaine (up to 100 μmol/L concentrations) did not induce apoptosis, but 200 to 1000 μmol/L cocaine induced apoptosis in a dose-dependent manner. Notably, treatment of CD4(+) T cells isolated from healthy donors with both HIV-1 virions and cocaine significantly increased apoptosis compared with the apoptosis induced by cocaine or virions alone. Most important, our biochemical data suggest that cocaine induces CD4(+) T-cell apoptosis by increasing intracellular reactive oxygen species levels and inducing mitochondrial depolarization. Collectively, our results provide evidence of a synergy between cocaine and HIV-1 on CD4(+) T-cell apoptosis that may, in part, explain the accelerated disease observed in HIV-1-infected drug abusers.

  10. Cocaine modulates HIV-1 integration in primary CD4+ T cells: implications in HIV-1 pathogenesis in drug-abusing patients.

    Science.gov (United States)

    Addai, Amma B; Pandhare, Jui; Paromov, Victor; Mantri, Chinmay K; Pratap, Siddharth; Dash, Chandravanu

    2015-04-01

    Epidemiologic studies suggest that cocaine abuse worsens HIV-1 disease progression. Increased viral load has been suggested to play a key role for the accelerated HIV disease among cocaine-abusing patients. The goal of this study was to investigate whether cocaine enhances proviral DNA integration as a mechanism to increase viral load. We infected CD4(+) T cells that are the primary targets of HIV-1 in vivo and treated the cells with physiologically relevant concentrations of cocaine (1 µM-100 µM). Proviral DNA integration in the host genome was measured by nested qPCR. Our results illustrated that cocaine from 1 µM through 50 µM increased HIV-1 integration in CD4(+) T cells in a dose-dependent manner. As integration can be modulated by several early postentry steps of HIV-1 infection, we examined the direct effects of cocaine on viral integration by in vitro integration assays by use of HIV-1 PICs. Our data illustrated that cocaine directly increases viral DNA integration. Furthermore, our MS analysis showed that cocaine is able to enter CD4(+) T cells and localize to the nucleus-. In summary, our data provide strong evidence that cocaine can increase HIV-1 integration in CD4(+) T cells. Therefore, we hypothesize that increased HIV-1 integration is a novel mechanism by which cocaine enhances viral load and worsens disease progression in drug-abusing HIV-1 patients.

  11. Rare HIV-1 Subtype J Genomes and a New H/U/CRF02_AG Recombinant Genome Suggests an Ancient Origin of HIV-1 in Angola.

    Science.gov (United States)

    Bártolo, Inês; Calado, Rita; Borrego, Pedro; Leitner, Thomas; Taveira, Nuno

    2016-08-01

    Angola has an extremely diverse HIV-1 epidemic fueled in part by the frequent interchange of people with the Democratic Republic of Congo (DRC) and Republic of Congo (RC). Characterization of HIV-1 strains circulating in Angola should help to better understand the origin of HIV-1 subtypes and recombinant forms and their transmission dynamics. In this study we characterize the first near full-length HIV-1 genomic sequences from HIV-1 infected individuals from Angola. Samples were obtained in 1993 from three HIV-1 infected patients living in Cabinda, Angola. Near full-length genomic sequences were obtained from virus isolates. Maximum likelihood phylogenetic tree inference and analyses of potential recombination patterns were performed to evaluate the sequence classifications and origins. Phylogenetic and recombination analyses revealed that one virus was a pure subtype J, another mostly subtype J with a small uncertain region, and the final virus was classified as a H/U/CRF02_AG recombinant. Consistent with their epidemiological data, the subtype J sequences were more closely related to each other than to other J sequences previously published. Based on the env gene, taxa from Angola occur throughout the global subtype J phylogeny. HIV-1 subtypes J and H are present in Angola at low levels since at least 1993. Low transmission efficiency and/or high recombination potential may explain their limited epidemic success in Angola and worldwide. The high diversity of rare subtypes in Angola suggests that Angola was part of the early establishment of the HIV-1 pandemic.

  12. Generation of HIV-1 and Internal Control Transcripts as Standards for an In-House Quantitative Competitive RT-PCR Assay to Determine HIV-1 Viral Load

    Directory of Open Access Journals (Sweden)

    Anny Armas Cayarga

    2011-01-01

    Full Text Available Human immunodeficiency virus type-1 (HIV-1 viral load is useful for monitoring disease progression in HIV-infected individuals. We generated RNA standards of HIV-1 and internal control (IC by in vitro transcription and evaluated its performance in a quantitative reverse transcription polymerase chain reaction (qRT-PCR assay. HIV-1 and IC standards were obtained at high RNA concentrations, without DNA contamination. When these transcripts were included as standards in a qRT-PCR assay, it was obtained a good accuracy (±0.5 log10 unit of the expected results in the quantification of the HIV-1 RNA international standard and controls. The lower limit detection achieved using these standards was 511.0 IU/mL. A high correlation (=0.925 was obtained between the in-house qRT-PCR assay and the NucliSens easyQ HIV-1 test (bioMerieux for HIV-1 RNA quantitation with clinical samples (=14. HIV-1 and IC RNA transcripts, generated in this study, proved to be useful as standards in an in-house qRT-PCR assay for determination of HIV-1 viral load.

  13. Dynamic motions of the HIV-1 frameshift site RNA.

    Science.gov (United States)

    Mouzakis, Kathryn D; Dethoff, Elizabeth A; Tonelli, Marco; Al-Hashimi, Hashim; Butcher, Samuel E

    2015-02-03

    The HIV-1 frameshift site (FS) plays a critical role in viral replication. During translation, the HIV-1 FS transitions from a 3-helix to a 2-helix junction RNA secondary structure. The 2-helix junction structure contains a GGA bulge, and purine-rich bulges are common motifs in RNA secondary structure. Here, we investigate the dynamics of the HIV-1 FS 2-helix junction RNA. Interhelical motions were studied under different ionic conditions using NMR order tensor analysis of residual dipolar couplings. In 150 mM potassium, the RNA adopts a 43°(±4°) interhelical bend angle (β) and displays large amplitude, anisotropic interhelical motions characterized by a 0.52(±0.04) internal generalized degree of order (GDOint) and distinct order tensor asymmetries for its two helices (η = 0.26(±0.04) and 0.5(±0.1)). These motions are effectively quenched by addition of 2 mM magnesium (GDOint = 0.87(±0.06)), which promotes a near-coaxial conformation (β = 15°(±6°)) of the two helices. Base stacking in the bulge was investigated using the fluorescent purine analog 2-aminopurine. These results indicate that magnesium stabilizes extrahelical conformations of the bulge nucleotides, thereby promoting coaxial stacking of helices. These results are highly similar to previous studies of the HIV transactivation response RNA, despite a complete lack of sequence similarity between the two RNAs. Thus, the conformational space of these RNAs is largely determined by the topology of their interhelical junctions.

  14. Predicting Bevirimat resistance of HIV-1 from genotype

    Directory of Open Access Journals (Sweden)

    Hoffmann Daniel

    2010-01-01

    Full Text Available Abstract Background Maturation inhibitors are a new class of antiretroviral drugs. Bevirimat (BVM was the first substance in this class of inhibitors entering clinical trials. While the inhibitory function of BVM is well established, the molecular mechanisms of action and resistance are not well understood. It is known that mutations in the regions CS p24/p2 and p2 can cause phenotypic resistance to BVM. We have investigated a set of p24/p2 sequences of HIV-1 of known phenotypic resistance to BVM to test whether BVM resistance can be predicted from sequence, and to identify possible molecular mechanisms of BVM resistance in HIV-1. Results We used artificial neural networks and random forests with different descriptors for the prediction of BVM resistance. Random forests with hydrophobicity as descriptor performed best and classified the sequences with an area under the Receiver Operating Characteristics (ROC curve of 0.93 ± 0.001. For the collected data we find that p2 sequence positions 369 to 376 have the highest impact on resistance, with positions 370 and 372 being particularly important. These findings are in partial agreement with other recent studies. Apart from the complex machine learning models we derived a number of simple rules that predict BVM resistance from sequence with surprising accuracy. According to computational predictions based on the data set used, cleavage sites are usually not shifted by resistance mutations. However, we found that resistance mutations could shorten and weaken the α-helix in p2, which hints at a possible resistance mechanism. Conclusions We found that BVM resistance of HIV-1 can be predicted well from the sequence of the p2 peptide, which may prove useful for personalized therapy if maturation inhibitors reach clinical practice. Results of secondary structure analysis are compatible with a possible route to BVM resistance in which mutations weaken a six-helix bundle discovered in recent experiments

  15. HIV-1 clade B pol evolution following primary infection.

    Directory of Open Access Journals (Sweden)

    George K Hightower

    Full Text Available OBJECTIVE: Characterize intra-individual HIV-1 subtype B pol evolution in antiretroviral naive individuals. DESIGN: Longitudinal cohort study of individuals enrolled during primary infection. METHODS: Eligible individuals were antiretroviral naïve participants enrolled in the cohort from December 1997-December 2005 and having at least two blood samples available with the first one collected within a year of their estimated date of infection. Population-based pol sequences were generated from collected blood samples and analyzed for genetic divergence over time in respect to dual infection status, HLA, CD4 count and viral load. RESULTS: 93 participants were observed for a median of 1.8 years (Mean = 2.2 years, SD =1.9 years. All participants classified as mono-infected had less than 0.7% divergence between any two of their pol sequences using the Tamura-Nei model (TN93, while individuals with dual infection had up to 7.0% divergence. The global substitution rates (substitutions/nucleotide/year for mono and dually infected individuals were significantly different (p<0.001; however, substitution rates were not associated with HLA haplotype, CD4 or viral load. CONCLUSIONS: Even after a maximum of almost 9 years of follow-up, all mono-infected participants had less than 1% divergence between baseline and longitudinal sequences, while participants with dual infection had 10 times greater divergence. These data support the use of HIV-1 pol sequence data to evaluate transmission events, networks and HIV-1 dual infection.

  16. Genetic analysis of HIV-1 subtypes in Nairobi, Kenya.

    Directory of Open Access Journals (Sweden)

    Suhail Khoja

    Full Text Available BACKGROUND: Genetic analysis of a viral infection helps in following its spread in a given population, in tracking the routes of infection and, where applicable, in vaccine design. Additionally, sequence analysis of the viral genome provides information about patterns of genetic divergence that may have occurred during viral evolution. OBJECTIVE: In this study we have analyzed the subtypes of Human Immunodeficiency Virus -1 (HIV-1 circulating in a diverse sample population of Nairobi, Kenya. METHODOLOGY: 69 blood samples were collected from a diverse subject population attending the Aga Khan University Hospital in Nairobi, Kenya. Total DNA was extracted from peripheral blood mononuclear cells (PBMCs, and used in a Polymerase Chain Reaction (PCR to amplify the HIV gag gene. The PCR amplimers were partially sequenced, and alignment and phylogenetic analysis of these sequences was performed using the Los Alamos HIV Database. RESULTS: Blood samples from 69 HIV-1 infected subjects from varying ethnic backgrounds were analyzed. Sequence alignment and phylogenetic analysis showed 39 isolates to be subtype A, 13 subtype D, 7 subtype C, 3 subtype AD and CRF01_AE, 2 subtype G and 1 subtype AC and 1 AG. Deeper phylogenetic analysis revealed HIV subtype A sequences to be highly divergent as compared to subtypes D and C. CONCLUSION: Our analysis indicates that HIV-1 subtypes in the Nairobi province of Kenya are dominated by a genetically diverse clade A. Additionally, the prevalence of highly divergent, complex subtypes, intersubtypes, and the recombinant forms indicates viral mixing in Kenyan population, possibly as a result of dual infections.

  17. Structural mechanism of trimeric HIV-1 envelope glycoprotein activation.

    Directory of Open Access Journals (Sweden)

    Erin E H Tran

    Full Text Available HIV-1 infection begins with the binding of trimeric viral envelope glycoproteins (Env to CD4 and a co-receptor on target T-cells. Understanding how these ligands influence the structure of Env is of fundamental interest for HIV vaccine development. Using cryo-electron microscopy, we describe the contrasting structural outcomes of trimeric Env binding to soluble CD4, to the broadly neutralizing, CD4-binding site antibodies VRC01, VRC03 and b12, or to the monoclonal antibody 17b, a co-receptor mimic. Binding of trimeric HIV-1 BaL Env to either soluble CD4 or 17b alone, is sufficient to trigger formation of the open quaternary conformation of Env. In contrast, VRC01 locks Env in the closed state, while b12 binding requires a partial opening in the quaternary structure of trimeric Env. Our results show that, despite general similarities in regions of the HIV-1 gp120 polypeptide that contact CD4, VRC01, VRC03 and b12, there are important differences in quaternary structures of the complexes these ligands form on native trimeric Env, and potentially explain differences in the neutralizing breadth and potency of antibodies with similar specificities. From cryo-electron microscopic analysis at ∼9 Å resolution of a cleaved, soluble version of trimeric Env, we show that a structural signature of the open Env conformation is a three-helix motif composed of α-helical segments derived from highly conserved, non-glycosylated N-terminal regions of the gp41 trimer. The three N-terminal gp41 helices in this novel, activated Env conformation are held apart by their interactions with the rest of Env, and are less compactly packed than in the post-fusion, six-helix bundle state. These findings suggest a new structural template for designing immunogens that can elicit antibodies targeting HIV at a vulnerable, pre-entry stage.

  18. Morphine enhances HIV-1SF162-mediated neuron death and delays recovery of injured neurites.

    Directory of Open Access Journals (Sweden)

    Ruturaj R Masvekar

    Full Text Available HIV-1 enters the CNS soon after initial systemic infection; within the CNS parenchyma infected and/or activated perivascular macrophages, microglia and astrocytes release viral and cellular toxins that drive secondary toxicity in neurons and other cell types. Our previous work has largely modeled HIV-neuropathology using the individual viral proteins Tat or gp120, with murine striatal neurons as targets. To model disease processes more closely, the current study uses supernatant from HIV-1-infected cells. Supernatant from HIV-1SF162-infected differentiated-U937 cells (HIV+sup was collected and p24 level was measured by ELISA to assess the infection. Injection drug abuse is a significant risk factor for HIV-infection, and opiate drug abusers show increased HIV-neuropathology, even with anti-retroviral treatments. We therefore assessed HIV+sup effects on neuronal survival and neurite growth/pruning with or without concurrent exposure to morphine, an opiate that preferentially acts through µ-opioid receptors. Effects of HIV+sup ± morphine were assessed on neuronal populations, and also by time-lapse imaging of individual cells. HIV+sup caused dose-dependent toxicity over a range of p24 levels (10-500 pg/ml. Significant interactions occurred with morphine at lower p24 levels (10 and 25 pg/ml, and GSK3β was implicated as a point of convergence. In the presence of glia, selective neurotoxic measures were significantly enhanced and interactions with morphine were also augmented, perhaps related to a decreased level of BDNF. Importantly, the arrest of neurite growth that occurred with exposure to HIV+sup was reversible unless neurons were continuously exposed to morphine. Thus, while reducing HIV-infection levels may be protective, ongoing exposure to opiates may limit recovery. Opiate interactions observed in this HIV-infective environment were similar, though not entirely concordant, with Tat/gp120 interactions reported previously, suggesting

  19. APOBEC3 proteins can copackage and comutate HIV-1 genomes

    OpenAIRE

    Desimmie, Belete A.; Burdick, Ryan C.; Izumi, Taisuke; Doi, Hibiki; Shao, Wei; Alvord, W. Gregory; Sato, Kei; Koyanagi, Yoshio; Jones, Sara; Wilson, Eleanor; Hill, Shawn; Maldarelli, Frank; Hu, Wei-Shau; Pathak, Vinay K.

    2016-01-01

    Although APOBEC3 cytidine deaminases A3G, A3F, A3D and A3H are packaged into virions and inhibit viral replication by inducing G-to-A hypermutation, it is not known whether they are copackaged and whether they can act additively or synergistically to inhibit HIV-1 replication. Here, we showed that APOBEC3 proteins can be copackaged by visualization of fluorescently-tagged APOBEC3 proteins using single-virion fluorescence microscopy. We further determined that viruses produced in the presence ...

  20. Docking study of HIV-1 reverse transcriptase with phytochemicals.

    Science.gov (United States)

    Seal, Abhik; Aykkal, Riju; Babu, Rosana O; Ghosh, Mriganka

    2011-02-15

    Natural products are important sources of drug discovery. In this context groups of different set of phytochemicals were taken and docked into the different cavities of the Reverse transcriptase (PDB ID: 1REV) of Human immunodeficiency virus (HIV) and results were discussed. Natural compounds such as Curcumin, Geranin, Gallotannin, Tiliroside, Kaempferol-3-o-glucoside and Trachelogenin were found to very effective according to its binding energy and ligand efficiency score. Those compounds also were found to have no adverse effect as carcinogenicity and mutagenicity and favorable drug likeness score. Hence, considering the facts those compounds could use effectively for HIV-1 drug discovery.

  1. Indole-based allosteric inhibitors of HIV-1 integrase.

    Science.gov (United States)

    Patel, Pratiq A; Kvaratskhelia, Nina; Mansour, Yara; Antwi, Janet; Feng, Lei; Koneru, Pratibha; Kobe, Mathew J; Jena, Nivedita; Shi, Guqin; Mohamed, Mosaad S; Li, Chenglong; Kessl, Jacques J; Fuchs, James R

    2016-10-01

    Employing a scaffold hopping approach, a series of allosteric HIV-1 integrase (IN) inhibitors (ALLINIs) have been synthesized based on an indole scaffold. These compounds incorporate the key elements utilized in quinoline-based ALLINIs for binding to the IN dimer interface at the principal LEDGF/p75 binding pocket. The most potent of these compounds displayed good activity in the LEDGF/p75 dependent integration assay (IC50=4.5μM) and, as predicted based on the geometry of the five- versus six-membered ring, retained activity against the A128T IN mutant that confers resistance to many quinoline-based ALLINIs.

  2. Prediction of the secondary structure of HIV-1 gp120

    DEFF Research Database (Denmark)

    Hansen, J E; Lund, O; Nielsen, Jens Ole

    1996-01-01

    Fourier transform infrared spectroscopy. The predicted secondary structure of gp120 compared well with data from NMR analysis of synthetic peptides from the V3 loop and the C4 region. As a first step towards modeling the tertiary structure of gp120, the predicted secondary structure may guide the design......The secondary structure of HIV-1 gp120 was predicted using multiple alignment and a combination of two independent methods based on neural network and nearest-neighbor algorithms. The methods agreed on the secondary structure for 80% of the residues in BH10 gp120. Six helices were predicted in HIV...

  3. Prediction of the Secondary Structure of HIV-1 gp120

    DEFF Research Database (Denmark)

    Hansen, Jan; Lund, Ole; Nielsen, Jens O.

    1996-01-01

    Fourier transform infrared spectroscopy. The predicted secondary structure of gp120 compared well with data from NMR analysis of synthetic peptides from the V3 loop and the C4 region. As a first step towards modeling the tertiary structure of gp120, the predicted secondary structure may guide the design......The secondary structure of HIV-1 gp120 was predicted using multiple alignment and a combination of two independent methods based on neural network and nearest-neighbor algorithms. The methods agreed on the secondary structure for 80% of the residues in BH10 gp120. Six helices were predicted in HIV...

  4. Design and pre-clinical evaluation of a universal HIV-1 vaccine.

    Directory of Open Access Journals (Sweden)

    Sven Létourneau

    Full Text Available BACKGROUND: One of the big roadblocks in development of HIV-1/AIDS vaccines is the enormous diversity of HIV-1, which could limit the value of any HIV-1 vaccine candidate currently under test. METHODOLOGY AND FINDINGS: To address the HIV-1 variation, we designed a novel T cell immunogen, designated HIV(CONSV, by assembling the 14 most conserved regions of the HIV-1 proteome into one chimaeric protein. Each segment is a consensus sequence from one of the four major HIV-1 clades A, B, C and D, which alternate to ensure equal clade coverage. The gene coding for the HIV(CONSV protein was inserted into the three most studied vaccine vectors, plasmid DNA, human adenovirus serotype 5 and modified vaccine virus Ankara (MVA, and induced HIV-1-specific T cell responses in mice. We also demonstrated that these conserved regions prime CD8(+ and CD4(+ T cell to highly conserved epitopes in humans and that these epitopes, although usually subdominant, generate memory T cells in patients during natural HIV-1 infection. SIGNIFICANCE: Therefore, this vaccine approach provides an attractive and testable alternative for overcoming the HIV-1 variability, while focusing T cell responses on regions of the virus that are less likely to mutate and escape. Furthermore, this approach has merit in the simplicity of design and delivery, requiring only a single immunogen to provide extensive coverage of global HIV-1 population diversity.

  5. High levels of divergent HIV-1 quasispecies in patients with neurological opportunistic infections in China.

    Science.gov (United States)

    Zhang, Yulin; Wei, Feili; Liang, Qi; Ding, Wei; Qiao, Luxin; Song, Fengli; Liu, Lifeng; Yang, Sufang; Jin, Ronghua; Gu, Jianhua; Li, Ning; Chen, Dexi

    2013-08-01

    Despite the fact that the survival of people infected with human immunodeficiency virus (HIV) has improved worldwide because of the increasingly powerful and highly active antiretroviral therapy, opportunistic infections (OIs) of the central nervous system (CNS) remain a serious burden. HIV-1 is capable of entering the CNS through infected peripheral monocytes, but its effect on OIs of CNS remains unclear. In this study, we investigated the characteristics of HIV-1 in acquired immunodeficiency syndrome (AIDS) patients with CNS OIs. A total of 24 patients with CNS OIs and 16 non-CNS OIs (control) cases were selected. These AIDS patients were infected with HIV-1 by paid blood donors in China. HIV-1 loads in plasma and cerebrospinal fluid (CSF) were detected using RT-PCR, and the C2-V5 region of HIV-1 envelope gene was amplified from viral quasispecies isolated from CSF using nested PCR. The CSF HIV-1 load of CNS OIs was higher than that of non-CNS OIs, but plasma HIV-1 load of CNS OIs was not higher than that of non-CNS OIs. The nucleotide sequence of C2-V5 region of the HIV-1 quasispecies isolated from the CSF of CNS OIs had a high diversity, and the HIV-1 quasispecies isolated from the CSF of CNS OIs revealed R5 tropism as 11/25 charge rule. These results suggest that high levels of divergent HIV-1 quasispecies in the CNS probably contribute to opportunistic infections.

  6. Higher Desolvation Energy Reduces Molecular Recognition in Multi-Drug Resistant HIV-1 Protease

    Directory of Open Access Journals (Sweden)

    Ladislau C. Kovari

    2012-05-01

    Full Text Available Designing HIV-1 protease inhibitors that overcome drug-resistance is still a challenging task. In this study, four clinical isolates of multi-drug resistant HIV-1 proteases that exhibit resistance to all the US FDA-approved HIV-1 protease inhibitors and also reduce the substrate recognition ability were examined. A multi-drug resistant HIV-1 protease isolate, MDR 769, was co-crystallized with the p2/NC substrate and the mutated CA/p2 substrate, CA/p2 P1’F. Both substrates display different levels of molecular recognition by the wild-type and multi-drug resistant HIV-1 protease. From the crystal structures, only limited differences can be identified between the wild-type and multi-drug resistant protease. Therefore, a wild-type HIV-1 protease and four multi-drug resistant HIV-1 proteases in complex with the two peptides were modeled based on the crystal structures and examined during a 10 ns-molecular dynamics simulation. The simulation results reveal that the multi-drug resistant HIV-1 proteases require higher desolvation energy to form complexes with the peptides. This result suggests that the desolvation of the HIV-1 protease active site is an important step of protease-ligand complex formation as well as drug resistance. Therefore, desolvation energy could be considered as a parameter in the evaluation of future HIV-1 protease inhibitor candidates.

  7. Identification of HIV-1 Epitopes that Induce the Synthesis of a R5 HIV-1 Suppression Factor by Human CD4+ T Cells Isolated from HIV-1 Immunized Hu-PBL SCID Mice

    Directory of Open Access Journals (Sweden)

    Atsushi Yoshida

    2005-01-01

    Full Text Available We have previously reported that immunization of the severe combined immunodeficiency (SCID mice reconstituted with human peripheral blood mononuclear cells (PBMC (hu-PBL-SCID mice with inactivated human immunodeficiency virus type-1 (HIV-1-pulsed-autologous dendritic cells (HIV-DC elicits HIV-1-reactive CD4+ T cells that produce an as yet to be defined novel soluble factor in vitro with anti-viral properties against CCR5 tropic (R5 HIV-1 infection. These findings led us to perform studies designed to identify the lineage of the cell that synthesizes such a factor in vitro and define the epitopes of HIV-1 protein that have specificity for the induction of such anti-viral factor. Results of our studies show that this property is a function of CD4+ but not CD8+ T cells. Human CD4+ T cells were thus recovered from the HIV-DC-immunized hu-PBL-SCID mice and were re-stimulated in vitro by co-culture for 2 days with autologous adherent PBMC as antigen presenting cells, APC previously pulsed with inactivated HIV in IL-2-containing medium to expand HIV-1-reactive CD4+ T cells. Aliquots of these re-stimulated CD4+ T cells were then co-cultured with similar APC's that were previously pulsed with 10 μg/ml of a panel of HIV peptides for an additional 2 days, and their culture supernatants were examined for the production of both the R5 HIV-1 suppression factor and IFN-Υ. The data presented herein show that the HIV-1 primed CD4+ T cells produced the R5 suppression factor in response to a wide variety of HIV-1 gag, env, pol, nef or vif peptides, depending on the donor of the CD4+ T cells. Simultaneous production of human interferon (IFN-Υ was observed in some cases. These results indicate that human CD4+ T cells in PBMC of HIV-1 naive donors have a wide variety of HIV-1 epitope-specific CD4+ T cell precursors that are capable of producing the R5 HIV-1 suppression factor upon DC-based vaccination with whole inactivated HIV-1.

  8. Identification of HIV-1 epitopes that induce the synthesis of a R5 HIV-1 suppression factor by human CD4+ T cells isolated from HIV-1 immunized hu-PBL SCID mice.

    Science.gov (United States)

    Yoshida, Atsushi; Tanaka, Reiko; Kodama, Akira; Yamamoto, Naoki; Ansari, Aftab A; Tanaka, Yuetsu

    2005-12-01

    We have previously reported that immunization of the severe combined immunodeficiency (SCID) mice reconstituted with human peripheral blood mononuclear cells (PBMC) (hu-PBL-SCID mice) with inactivated human immunodeficiency virus type-1 (HIV-1)-pulsed-autologous dendritic cells (HIV-DC) elicits HIV-1-reactive CD4(+) T cells that produce an as yet to be defined novel soluble factor in vitro with anti-viral properties against CCR5 tropic (R5) HIV-1 infection. These findings led us to perform studies designed to identify the lineage of the cell that synthesizes such a factor in vivo and define the epitopes of HIV-1 protein that have specificity for the induction of such anti-viral factor. Results of our studies show that this property is a function of CD4(+) but not CD8(+) T cells. Human CD4(+) T cells were thus recovered from the HIV-DC-immunized hu-PBL-SCID mice and were re-stimulated in vitro by co-culture for 2 days with autologous adherent PBMC as antigen presenting cells, APC previously pulsed with inactivated HIV in IL-2-containing medium to expand HIV-1-reactive CD4(+) T cells. Aliquots of these re-stimulated CD4(+) T cells were then co-cultured with similar APC's that were previously pulsed with 10 microg/ml of a panel of HIV peptides for an additional 2 days, and their culture supernatants were examined for the production of both the R5 HIV-1 suppression factor and IFN-gamma. The data presented herein show that the HIV-1 primed CD4(+) T cells produced the R5 suppression factor in response to a wide variety of HIV-1 gag, env, pol, nef or vif peptides, depending on the donor of the CD4(+) T cells. Simultaneous production of human interferon (IFN)-gamma was observed in some cases. These results indicate that human CD4(+) T cells in PBMC of HIV-1 naive donors have a wide variety of HIV-1 epitope-specific CD4(+) T cell precursors that are capable of producing the R5 HIV-1 suppression factor upon DC-based vaccination with whole inactivated HIV-1.

  9. Anatomic dissociation between HIV-1 and its endogenous inhibitor in mucosal tissues.

    Science.gov (United States)

    Wahl, S. M.; Worley, P.; Jin, W.; McNeely, T. B.; Eisenberg, S.; Fasching, C.; Orenstein, J. M.; Janoff, E. N.

    1997-01-01

    The rarity of oral transmission of human immunodeficiency virus (HIV)-1 by saliva suggests the absence of HIV-1 in the oral cavity and/or the presence of viral inhibitory molecules. We analyzed salivary gland tissues from 55 individuals with acquired immune deficiency syndrome (AIDS) for the presence of HIV-1 by in situ hybridization and detected the virus in more than 30% of these salivary glands. These data, together with previous demonstrations of HIV-1 in oral secretions, implicate a key role for an anti-viral molecule(s) in suppressing transmission. Thus, we focused on the characterization and localization of the endogenous antiviral molecule secretory leukocyte protease inhibitor (SLPI), which inhibits HIV-1 infection in vitro. Expression of SLPI transcripts was evident in submandibular, parotid, and minor salivary glands from both HIV-1-infected and seronegative subjects. Gene expression was reflected by similar levels of SLPI protein by immunohistochemical analysis in the tissues and by enzyme-linked immunosorbent assay in the saliva. However, although SLPI accumulated in acinar cells or ductal epithelium, HIV-1 transcripts did not, and these viral transcripts were identified only in mononuclear cells within the salivary gland stroma. By in situ hybridization, we found no evidence of productive HIV-1 infection of salivary gland epithelium. Thus, HIV-1 was frequently identified in salivary gland tissue, but the virus was found in interstitial mononuclear cells only and did not co-localize with SLPI. Once within the oral cavity, HIV-1 exposure to antiviral levels of SLPI may impede infection of additional target cells, contributing to the virtual absence of oral transmission of HIV-1 by saliva. These studies emphasize the importance of innate, endogenous inhibitors of HIV-1, particularly SLPI, as effective inhibitors of HIV-1 transmission. Images Figure 1 Figure 3 Figure 4 Figure 5 PMID:9094984

  10. Modulation of HIV-1 virulence via the host glucocorticoid receptor: towards further understanding the molecular mechanisms of HIV-1 pathogenesis.

    Science.gov (United States)

    Hapgood, Janet Patricia; Tomasicchio, Michele

    2010-07-01

    The glucocorticoid receptor (GR) is a steroid receptor that regulates diverse functions, which include the immune response. In humans, the GR acts via binding to cortisol, resulting in the transcriptional modulation of key host genes. Several lines of evidence suggest that the host GR could be a key protein exploited by HIV at multiple levels to ensure its pathogenic success. Endogenous and therapeutic glucocorticoids play important roles in patients with HIV due to their well-established effects on immune function. AIDS patients develop glucocorticoid hypersensitivity, consistent with a mechanism involving an HIV-1-induced increase in expression or activity of the GR. Both the HIV-1 accessory protein Vpr and the host GR affect transcription of viral proteins from the long terminal repeat (LTR) region of the HIV-1 promoter. In addition, Vpr modulates host GR function to affect transcription of host genes, most likely via direct interaction with the GR. Vpr appears to regulate GR function by acting as a co-activator for the GR. Since both the GR and Vpr are involved in apoptosis in T cells and dendritic cells, crosstalk between these proteins may also regulate apoptosis in these and other cells. Given that cortisol is not the only ligand that activates the GR, other endogenous as well as synthetic GR ligands such as progestins may also modulate HIV pathogenesis, in particular in the cervicovaginal environment. Investigating the molecular determinants, ligand-selectivity and role in HIV pathogenesis of the GR-Vpr interaction may lead to new strategies for development of anti-HIV drugs.

  11. Association of Neutralization Sensitivity of HIV- 1 Primary Isolates With Biological Properties of Isolates From HIV-1 Infected Chinese Individuals

    Institute of Scientific and Technical Information of China (English)

    FA-XIN HEI; HAI-LI TANG; KUN-XUE HONG; JIAN-PING CHEN; HONG PENG; LIN YUAN; JIANG-QING XU; YI-MING SHAO

    2005-01-01

    Objective Although HIV-1 infection is prevalent in many regions in China, it remains largely unknown on the biological characteristics of dominant circulating isolates. This study was designed to isolate the circulating viral strains from different prevalent regions and to characterize their biological properties and neutralization sensitivity. Methods Primary viruses were isolated from fresh PBMCs using the traditional co-culture method and their capacity of inducing syncytium was tested in MT-2 cells. Meanwhile, their coreceptor usage was determined with two cell lines: Magi and GHOST (3) stably expressing CD4 and the chemokine receptor CCR5 or CXCR4. Furthermore, the sensitivity of these viruses to neutralization by HIV-1-infected patients' plasma which were highly active to neutralize SF33 strain, was quantified in GHOST cell-based neutralization assay. Results Six primary viral strains were isolated from 4 separated regions. Isolates LTG0213,LTG0214 and XVS032691 induced syncytia in MT-2 cells, and used CXCR4 as coreceptor. Isolates XJN0021, XJN0091, or SHXDC0041 did not induce syncytia, and used CCR5 as coreceptor. Overall neutralization sensitivity differed among four representative strains: HIV-1 XVS032691>LTG0214>XJN0091≈SHXDC0041. Conclusion The neutralization sensitivity of HIV isolates is linked with the phenotype of isolates, in which syncytium-inducing (SI) or CXCR4-tropic (X4) viruses are more easily neutralized than non-syncytium-inducing (NSI) or CCR5-tropic (R5) viruses. The genetic subtypes based on the phylogeny of env sequences are not classical neutralization serotypes.

  12. Development of an HIV-1 Subtype Panel in China: Isolation and Characterization of 30 HIV-1 Primary Strains Circulating in China.

    Directory of Open Access Journals (Sweden)

    Jingwan Han

    Full Text Available The complex epidemic and significant diversity of HIV-1 strains in China pose serious challenges for surveillance and diagnostic assays, vaccine development and clinical management. There is a lack of HIV-1 isolates in current canonical HIV-1 subtype panels that can represent HIV-1 diversity in China; an HIV-1 subtype panel for China is urgently needed.Blood samples were collected from HIV-1 infected patients participating in the drug-resistance surveillance program in China. The samples were isolated, cultured and stored as neat culture supernatant. The HIV-1 isolates were fully characterized. The panel was used to compare 2 viral load assays and 2 p24 assays as the examples of how this panel could be used.An HIV-1 subtype panel for China composed of 30 HIV-1 primary strains of four subtypes (B [including Thai-B], CRF01_AE, CRF07_BC and G was established. The samples were isolated and cultured to a high-titer (10(6-10(9 copies/ml/high-volume (40 ml. The HIV-1 isolates were fully characterized by the final viral load, p24 concentration, gag-pol and envC2V3 sequencing, co-receptor prediction, determination of the four amino acids at the tip of the env V3-loop, glycosylation sites in the V3 loop and the drug-resistance mutations. The comparison of two p24 assays and two viral load assays on the isolates illustrated how this panel may be used for the evaluation of diagnostic assay performance. The Pearson value between p24 assays were 0.938. The viral load results showed excellent concordance and agreement for samples of Thai-B, but lower correlations for samples of CRF01_AE.The current panel of 30 HIV-1 isolates served as a basis for the development of a comprehensive panel of fully characterized viral isolates, which could reflect the current dynamic and complex HIV-1 epidemic in China. This panel will be available to support HIV-1 research, assay evaluation, vaccine and drug development.

  13. The cell biology of HIV-1 and other retroviruses

    Directory of Open Access Journals (Sweden)

    Mouland Andrew J

    2006-11-01

    Full Text Available Abstract In recognition of the growing influence of cell biology in retrovirus research, we recently organized a Summer conference sponsored by the American Society for Cell Biology (ASCB on the Cell Biology of HIV-1 and other Retroviruses (July 20–23, 2006, Emory University, Atlanta, Georgia. The meeting brought together a number of leading investigators interested in the interplay between cell biology and retrovirology with an emphasis on presentation of new and unpublished data. The conference was arranged from early to late events in the virus replication cycle, with sessions on viral fusion, entry, and transmission; post-entry restrictions to retroviral infection; nuclear import and integration; gene expression/regulation of retroviral Gag and genomic RNA; and assembly/release. In this review, we will attempt to touch briefly on some of the highlights of the conference, and will emphasize themes and trends that emerged at the meeting. Meeting report The conference began with a keynote address from W. Sundquist on the biochemistry of HIV-1 budding. This presentation will be described in the section on Assembly and Release of Retroviruses.

  14. Pentosan polysulfate as an inhibitor of extracellular HIV-1 Tat.

    Science.gov (United States)

    Rusnati, M; Urbinati, C; Caputo, A; Possati, L; Lortat-Jacob, H; Giacca, M; Ribatti, D; Presta, M

    2001-06-22

    HIV-1 Tat protein, released from HIV-infected cells, may act as a pleiotropic heparin-binding growth factor. From this observation, extracellular Tat has been implicated in the pathogenesis of AIDS and of AIDS-associated pathologies. Here we demonstrate that the heparin analog pentosan polysulfate (PPS) inhibits the interaction of glutathione S-transferase (GST)-Tat protein with heparin immobilized to a BIAcore sensor chip. Competition experiments showed that Tat-PPS interaction occurs with high affinity (K(d) = 9.0 nm). Also, GST.Tat prevents the binding of [(3)H]heparin to GST.Tat immobilized to glutathione-agarose beads. In vitro, PPS inhibits GST.Tat internalization and, consequently, HIV-1 long terminal repeat transactivation in HL3T1 cells. Also, PPS inhibits cell surface interaction and mitogenic activity of GST.Tat in murine adenocarcinoma T53 Tat-less cells. In all assays, PPS exerts its Tat antagonist activity with an ID(50) equal to approximately 1.0 nm. In vivo, PPS inhibits the neovascularization induced by GST.Tat or by Tat-overexpressing T53 cells in the chick embryo chorioallantoic membrane. In conclusion, PPS binds Tat protein and inhibits its cell surface interaction, internalization, and biological activity in vitro and in vivo. PPS may represent a prototypic molecule for the development of novel Tat antagonists with therapeutic implications in AIDS and AIDS-associated pathologies, including Kaposi's sarcoma.

  15. Appreciating HIV-1 diversity: subtypic differences in ENV

    Energy Technology Data Exchange (ETDEWEB)

    Gnanakaran, S [Los Alamos National Laboratory; Shen, Tongye [Los Alamos National Laboratory; Lynch, Rebecca M [NON LANL; Derdeyn, Cynthia A [NON LANL

    2008-01-01

    Human immunodeficiency virus type 1 (HIV-1) group M is responsible for the current AIDS pandemic and exhibits exceedingly high levels of viral genetic diversity around the world, necessitating categorization of viruses into distinct lineages, or subtypes. These subtypes can differ by around 35% in the envelope (Env) glycoproteins of the virus, which are displayed on the surface of the virion and are targets for both neutralizing antibody and cell-mediated immune responses. This diversity reflects the remarkable ability of the virus to adapt to selective pressures, the bulk of which is applied by the host immune response, and represents a serious obstacle for developing an effective vaccine with broad coverage. Thus, it is important to understand the underlying biological consequences of inter-subtype diversity. Recent studies have revealed that the HIV-1 subtypes exhibit phenotypic differences that result from subtle differences in Env structure, particularly within the highly immunogenic V3 domain, which participates directly in viral entry. This review will therefore explore current research that describes subtypic differences in Env at the genetic and phenotypic level, focusing in particular on V3, and highlighting recent discoveries about the unique features of subtype C Env, which is the most prevalent subtype globally.

  16. Sequence determinants of breakpoint location during HIV-1 intersubtype recombination.

    Science.gov (United States)

    Baird, Heather A; Galetto, Román; Gao, Yong; Simon-Loriere, Etienne; Abreha, Measho; Archer, John; Fan, Jun; Robertson, David L; Arts, Eric J; Negroni, Matteo

    2006-01-01

    Retroviral recombination results from strand switching, during reverse transcription, between the two copies of genomic RNA present in the virus. We analysed recombination in part of the envelope gene, between HIV-1 subtype A and D strains. After a single infection cycle, breakpoints clustered in regions corresponding to the constant portions of Env. With some exceptions, a similar distribution was observed after multiple infection cycles, and among recombinant sequences in the HIV Sequence Database. We compared the experimental data with computer simulations made using a program that only allows recombination to occur whenever an identical base is present in the aligned parental RNAs. Experimental recombination was more frequent than expected on the basis of simulated recombination when, in a region spanning 40 nt from the 5' border of a breakpoint, no more than two discordant bases between the parental RNAs were present. When these requirements were not fulfilled, breakpoints were distributed randomly along the RNA, closer to the distribution predicted by computer simulation. A significant preference for recombination was also observed for regions containing homopolymeric stretches. These results define, for the first time, local sequence determinants for recombination between divergent HIV-1 isolates.

  17. Sequence determinants of breakpoint location during HIV-1 intersubtype recombination

    Science.gov (United States)

    Baird, Heather A.; Galetto, Román; Gao, Yong; Simon-Loriere, Etienne; Abreha, Measho; Archer, John; Fan, Jun; Robertson, David L.; Arts, Eric J.; Negroni, Matteo

    2006-01-01

    Retroviral recombination results from strand switching, during reverse transcription, between the two copies of genomic RNA present in the virus. We analysed recombination in part of the envelope gene, between HIV-1 subtype A and D strains. After a single infection cycle, breakpoints clustered in regions corresponding to the constant portions of Env. With some exceptions, a similar distribution was observed after multiple infection cycles, and among recombinant sequences in the HIV Sequence Database. We compared the experimental data with computer simulations made using a program that only allows recombination to occur whenever an identical base is present in the aligned parental RNAs. Experimental recombination was more frequent than expected on the basis of simulated recombination when, in a region spanning 40 nt from the 5′ border of a breakpoint, no more than two discordant bases between the parental RNAs were present. When these requirements were not fulfilled, breakpoints were distributed randomly along the RNA, closer to the distribution predicted by computer simulation. A significant preference for recombination was also observed for regions containing homopolymeric stretches. These results define, for the first time, local sequence determinants for recombination between divergent HIV-1 isolates. PMID:17003055

  18. Bayesian estimation of HIV-1 dynamics in vivo.

    Science.gov (United States)

    Ushakova, Anastasia; Pettersen, Frank Olav; Mæland, Arild; Lindqvist, Bo Henry; Kvale, Dag

    2015-03-01

    Statistical analysis of viral dynamics in HIV-1 infected patients undergoing structured treatment interruptions were performed using a novel model that accounts for treatment efficiency as well as total CD8+ T cell counts. A brief review of parameter estimates obtained in other studies is given, pointing to a considerable variation in the estimated values. A Bayesian approach to parameter estimation was used with longitudinal measurements of CD4+ and CD8+ T cell counts and HIV RNA. We describe an estimation procedure which uses spline approximations of CD8+ T cells dynamics. This approach reduces the number of parameters that must be estimated and is especially helpful when the CD8+ T cells growth function has a delayed dependence on the past. Seven important parameters related to HIV-1 in-host dynamics were estimated, most of them treated as global parameters across the group of patients. The estimated values were mainly in keeping with the estimates obtained in other reports, but our paper also introduces the estimates of some new parameters which supplement the current knowledge. The method was also tested on a simulated data set.

  19. Large-scale functional purification of recombinant HIV-1 capsid.

    Directory of Open Access Journals (Sweden)

    Magdeleine Hung

    Full Text Available During human immunodeficiency virus type-1 (HIV-1 virion maturation, capsid proteins undergo a major rearrangement to form a conical core that protects the viral nucleoprotein complexes. Mutations in the capsid sequence that alter the stability of the capsid core are deleterious to viral infectivity and replication. Recently, capsid assembly has become an attractive target for the development of a new generation of anti-retroviral agents. Drug screening efforts and subsequent structural and mechanistic studies require gram quantities of active, homogeneous and pure protein. Conventional means of laboratory purification of Escherichia coli expressed recombinant capsid protein rely on column chromatography steps that are not amenable to large-scale production. Here we present a function-based purification of wild-type and quadruple mutant capsid proteins, which relies on the inherent propensity of capsid protein to polymerize and depolymerize. This method does not require the packing of sizable chromatography columns and can generate double-digit gram quantities of functionally and biochemically well-behaved proteins with greater than 98% purity. We have used the purified capsid protein to characterize two known assembly inhibitors in our in-house developed polymerization assay and to measure their binding affinities. Our capsid purification procedure provides a robust method for purifying large quantities of a key protein in the HIV-1 life cycle, facilitating identification of the next generation anti-HIV agents.

  20. Iron status in HIV-1 infection: implications in disease pathology

    Directory of Open Access Journals (Sweden)

    Banjoko S Olatunbosun

    2012-12-01

    Full Text Available Abstract Background There had been conflicting reports with levels of markers of iron metabolism in HIV infection. This study was therefore aimed at investigating iron status and its possible mediation of severity of HIV- 1 infection and pathogenesis. Method Eighty (80 anti-retroviral naive HIV-1 positive and 50 sero-negative controls were recruited for the study. Concentrations of serum total iron, transferrin, total iron binding capacity (TIBC, CD4+ T -lymphocytes, vitamin C, zinc, selenium and transferrin saturation were estimated. Results The mean CD4+ T-lymphocyte cell counts, serum iron, TIBC, transferrin saturation for the tests and controls were 319 ± 22, 952 ± 57 cells/μl (P 4+ T-lymphocyte cell count had a positive correlation with levels of vitamin C (r = 0.497, P Conclusion It could be inferred that derangement in iron metabolism, in addition to oxidative stress, might have contributed to the depletion of CD4+ T cell population in our subjects and this may result in poor prognosis of the disease.

  1. Tetherin restricts productive HIV-1 cell-to-cell transmission.

    Directory of Open Access Journals (Sweden)

    Nicoletta Casartelli

    Full Text Available The IFN-inducible antiviral protein tetherin (or BST-2/CD317/HM1.24 impairs release of mature HIV-1 particles from infected cells. HIV-1 Vpu antagonizes the effect of tetherin. The fate of virions trapped at the cell surface remains poorly understood. Here, we asked whether tetherin impairs HIV cell-to-cell transmission, a major means of viral spread. Tetherin-positive or -negative cells, infected with wild-type or DeltaVpu HIV, were used as donor cells and cocultivated with target lymphocytes. We show that tetherin inhibits productive cell-to-cell transmission of DeltaVpu to targets and impairs that of WT HIV. Tetherin accumulates with Gag at the contact zone between infected and target cells, but does not prevent the formation of virological synapses. In the presence of tetherin, viruses are then mostly transferred to targets as abnormally large patches. These viral aggregates do not efficiently promote infection after transfer, because they accumulate at the surface of target cells and are impaired in their fusion capacities. Tetherin, by imprinting virions in donor cells, is the first example of a surface restriction factor limiting viral cell-to-cell spread.

  2. HIV-1 Populations in Semen Arise through Multiple Mechanisms.

    Directory of Open Access Journals (Sweden)

    Jeffrey A Anderson

    Full Text Available HIV-1 is present in anatomical compartments and bodily fluids. Most transmissions occur through sexual acts, making virus in semen the proximal source in male donors. We find three distinct relationships in comparing viral RNA populations between blood and semen in men with chronic HIV-1 infection, and we propose that the viral populations in semen arise by multiple mechanisms including: direct import of virus, oligoclonal amplification within the seminal tract, or compartmentalization. In addition, we find significant enrichment of six out of nineteen cytokines and chemokines in semen of both HIV-infected and uninfected men, and another seven further enriched in infected individuals. The enrichment of cytokines involved in innate immunity in the seminal tract, complemented with chemokines in infected men, creates an environment conducive to T cell activation and viral replication. These studies define different relationships between virus in blood and semen that can significantly alter the composition of the viral population at the source that is most proximal to the transmitted virus.

  3. Altered immunological reactivity in HIV-1-exposed uninfected neonates.

    Science.gov (United States)

    Hygino, Joana; Lima, Patrícia G; Filho, Renato G S; Silva, Agostinho A L; Saramago, Carmen S M; Andrade, Regis M; Andrade, Daniel M; Andrade, Arnaldo F B; Brindeiro, Rodrigo; Tanuri, Amilcar; Bento, Cleonice A M

    2008-06-01

    This work aimed to evaluate immune events in HIV-1-exposed uninfected neonates born from mothers who control (G1) or not (G2) the plasma viral load, using unexposed neonates as controls. Cord blood from each neonate was collected, plasma and mononuclear cells were separated and the lymphoproliferation and cytokine pattern were evaluated. The results demonstrated that the in vitro lymphoproliferation induced by polyclonal activators was higher in the G2 neonates. Nevertheless, no cell culture responded to poll synthetic HIV-1 envelope peptides. The cytokine dosage in the plasma and supernatants of polyclonally-activated cultures demonstrated that, while IL-4 and IL-10 were the dominant cytokines produced in G1 and control groups, IFN-gamma and TNF-alpha were significantly higher in G2 neonates. Systemic levels of IL-10 observed among the G1 neonates were higher in those born from anti-retroviral treated mothers. In summary, our results indicate an altered immune responsiveness in neonates exposed in utero to HIV and support the role of maternal anti-retroviral treatment to attenuate it.

  4. Hydrophobic Core Flexibility Modulates Enzyme Activity in HIV-1 Protease

    Energy Technology Data Exchange (ETDEWEB)

    Mittal, Seema; Cai, Yufeng; Nalam, Madhavi N.L.; Bolon, Daniel N.A.; Schiffer, Celia A. (UMASS, MED)

    2012-09-11

    Human immunodeficiency virus Type-1 (HIV-1) protease is crucial for viral maturation and infectivity. Studies of protease dynamics suggest that the rearrangement of the hydrophobic core is essential for enzyme activity. Many mutations in the hydrophobic core are also associated with drug resistance and may modulate the core flexibility. To test the role of flexibility in protease activity, pairs of cysteines were introduced at the interfaces of flexible regions remote from the active site. Disulfide bond formation was confirmed by crystal structures and by alkylation of free cysteines and mass spectrometry. Oxidized and reduced crystal structures of these variants show the overall structure of the protease is retained. However, cross-linking the cysteines led to drastic loss in enzyme activity, which was regained upon reducing the disulfide cross-links. Molecular dynamics simulations showed that altered dynamics propagated throughout the enzyme from the engineered disulfide. Thus, altered flexibility within the hydrophobic core can modulate HIV-1 protease activity, supporting the hypothesis that drug resistant mutations distal from the active site can alter the balance between substrate turnover and inhibitor binding by modulating enzyme activity.

  5. Copy number variation of KIR genes influences HIV-1 control

    DEFF Research Database (Denmark)

    Pelak, Kimberly; Need, Anna C; Fellay, Jacques;

    2011-01-01

    A genome-wide screen for large structural variants showed that a copy number variant (CNV) in the region encoding killer cell immunoglobulin-like receptors (KIR) associates with HIV-1 control as measured by plasma viral load at set point in individuals of European ancestry. This CNV encompasses...... the KIR3DL1-KIR3DS1 locus, encoding receptors that interact with specific HLA-Bw4 molecules to regulate the activation of lymphocyte subsets including natural killer (NK) cells. We quantified the number of copies of KIR3DS1 and KIR3DL1 in a large HIV-1 positive cohort, and showed that an increase in KIR3......DS1 count associates with a lower viral set point if its putative ligand is present (p = 0.00028), as does an increase in KIR3DL1 count in the presence of KIR3DS1 and appropriate ligands for both receptors (p = 0.0015). We further provide functional data that demonstrate that NK cells from...

  6. Genomic architecture of HIV-1 infection: current status & challenges.

    Science.gov (United States)

    Kaur, Gurvinder; Sharma, Gaurav; Kumar, Neeraj; Kaul, Mrinali H; Bansal, Rhea A; Vajpayee, Madhu; Wig, Naveet; Sharma, Surender K; Mehra, Narinder K

    2013-11-01

    Studies on host genomics have revealed the existence of identifiable HIV-1 specific protective factors among infected individuals who remain naturally resistant viraemia controllers with little or no evidence of virus replication. These factors are broadly grouped into those that are immune associated (MHC, chemokines, cytokines, CTLs and others), linked to viral entry (chemokine co-receptors and ligands), act as post-entry restriction elements (TRIM5a, APOBEC3) and those associated with viral replication (cytokines and others). These features have been identified through multiple experimental approaches ranging from candidate gene approaches, genome wide association studies (GWAS), expression analysis in conjunction with functional assays in humans to primate based models. Several studies have highlighted the individual and population level gross differences both in the viral clade sequences as well as host determined genetic associations. This review collates current information on studies involving major histocompatibility complex (MHC) as well as non MHC genes in the context of HIV-1 infection and AIDS involving varied ethnic groups. Special focus of the review is on the genetic studies carried out on the Indian population. Further challenges with regard to therapeutic interventions based on current knowledge have been discussed along with discussion on documented cases of stem cell therapy and very early highly active antiretroviral therapy (HAART) interventions.

  7. HIV-1 Tat interacts with LIS1 protein

    Directory of Open Access Journals (Sweden)

    Turner Willie

    2005-02-01

    Full Text Available Abstract Background HIV-1 Tat activates transcription of HIV-1 viral genes by inducing phosphorylation of the C-terminal domain (CTD of RNA polymerase II (RNAPII. Tat can also disturb cellular metabolism by inhibiting proliferation of antigen-specific T lymphocytes and by inducing cellular apoptosis. Tat-induced apoptosis of T-cells is attributed, in part, to the distortion of microtubules polymerization. LIS1 is a microtubule-associated protein that facilitates microtubule polymerization. Results We identified here LIS1 as a Tat-interacting protein during extensive biochemical fractionation of T-cell extracts. We found several proteins to co-purify with a Tat-associated RNAPII CTD kinase activity including LIS1, CDK7, cyclin H, and MAT1. Tat interacted with LIS1 but not with CDK7, cyclin H or MAT1 in vitro. LIS1 also co-immunoprecipitated with Tat expressed in HeLa cells. Further, LIS1 interacted with Tat in a yeast two-hybrid system. Conclusion Our results indicate that Tat interacts with LIS1 in vitro and in vivo and that this interaction might contribute to the effect of Tat on microtubule formation.

  8. Exploring the complexity of the HIV-1 fitness landscape.

    Directory of Open Access Journals (Sweden)

    Roger D Kouyos

    Full Text Available Although fitness landscapes are central to evolutionary theory, so far no biologically realistic examples for large-scale fitness landscapes have been described. Most currently available biological examples are restricted to very few loci or alleles and therefore do not capture the high dimensionality characteristic of real fitness landscapes. Here we analyze large-scale fitness landscapes that are based on predictive models for in vitro replicative fitness of HIV-1. We find that these landscapes are characterized by large correlation lengths, considerable neutrality, and high ruggedness and that these properties depend only weakly on whether fitness is measured in the absence or presence of different antiretrovirals. Accordingly, adaptive processes on these landscapes depend sensitively on the initial conditions. While the relative extent to which mutations affect fitness on their own (main effects or in combination with other mutations (epistasis is a strong determinant of these properties, the fitness landscape of HIV-1 is considerably less rugged, less neutral, and more correlated than expected from the distribution of main effects and epistatic interactions alone. Overall this study confirms theoretical conjectures about the complexity of biological fitness landscapes and the importance of the high dimensionality of the genetic space in which adaptation takes place.

  9. The evolutionary rate dynamically tracks changes in HIV-1 epidemics

    Energy Technology Data Exchange (ETDEWEB)

    Maljkovic-berry, Irina [Los Alamos National Laboratory; Athreya, Gayathri [Los Alamos National Laboratory; Daniels, Marcus [Los Alamos National Laboratory; Bruno, William [Los Alamos National Laboratory; Korber, Bette [Los Alamos National Laboratory; Kuiken, Carla [Los Alamos National Laboratory; Ribeiro, Ruy M [Los Alamos National Laboratory

    2009-01-01

    Large-sequence datasets provide an opportunity to investigate the dynamics of pathogen epidemics. Thus, a fast method to estimate the evolutionary rate from large and numerous phylogenetic trees becomes necessary. Based on minimizing tip height variances, we optimize the root in a given phylogenetic tree to estimate the most homogenous evolutionary rate between samples from at least two different time points. Simulations showed that the method had no bias in the estimation of evolutionary rates and that it was robust to tree rooting and topological errors. We show that the evolutionary rates of HIV-1 subtype B and C epidemics have changed over time, with the rate of evolution inversely correlated to the rate of virus spread. For subtype B, the evolutionary rate slowed down and tracked the start of the HAART era in 1996. Subtype C in Ethiopia showed an increase in the evolutionary rate when the prevalence increase markedly slowed down in 1995. Thus, we show that the evolutionary rate of HIV-1 on the population level dynamically tracks epidemic events.

  10. Tat RNA silencing suppressor activity contributes to perturbation of lymphocyte miRNA by HIV-1

    Directory of Open Access Journals (Sweden)

    Yu Lianbo

    2011-05-01

    Full Text Available Abstract Background MicroRNA (miRNA-mediated RNA silencing is integral to virtually every cellular process including cell cycle progression and response to virus infection. The interplay between RNA silencing and HIV-1 is multifaceted, and accumulating evidence posits a strike-counterstrike interface that alters the cellular environment to favor virus replication. For instance, miRNA-mediated RNA silencing of HIV-1 translation is antagonized by HIV-1 Tat RNA silencing suppressor activity. The activity of HIV-1 accessory proteins Vpr/Vif delays cell cycle progression, which is a process prominently modulated by miRNA. The expression profile of cellular miRNA is altered by HIV-1 infection in both cultured cells and clinical samples. The open question stands of what, if any, is the contribution of Tat RNA silencing suppressor activity or Vpr/Vif activity to the perturbation of cellular miRNA by HIV-1. Results Herein, we compared the perturbation of miRNA expression profiles of lymphocytes infected with HIV-1NL4-3 or derivative strains that are deficient in Tat RNA silencing suppressor activity (Tat K51A substitution or ablated of the vpr/vif open reading frames. Microarrays recapitulated the perturbation of the cellular miRNA profile by HIV-1 infection. The miRNA expression trends overlapped ~50% with published microarray results on clinical samples from HIV-1 infected patients. Moreover, the number of miRNA perturbed by HIV-1 was largely similar despite ablation of Tat RSS activity and Vpr/Vif; however, the Tat RSS mutation lessened HIV-1 downregulation of twenty-two miRNAs. Conclusions Our study identified miRNA expression changes attributable to Tat RSS activity in HIV-1NL4-3. The results accomplish a necessary step in the process to understand the interface of HIV-1 with host RNA silencing activity. The overlap in miRNA expression trends observed between HIV-1 infected CEMx174 lymphocytes and primary cells supports the utility of cultured

  11. In silico prediction of mutant HIV-1 proteases cleaving a target sequence

    CERN Document Server

    Jensen, Jan H; Winther, Jakob R; De Vico, Luca

    2014-01-01

    HIV-1 protease represents an appealing system for directed enzyme re-design, since it has various different endogenous targets, a relatively simple structure and it is well studied. Recently Chaudhury and Gray (Structure (2009) 17: 1636 -- 1648) published a computational algorithm to discern the specificity determining residues of HIV-1 protease. In this paper we present two computational tools aimed at re-designing HIV-1 protease, derived from the algorithm of Chaudhuri and Gray. First, we present an energy-only based methodology to discriminate cleavable and non cleavable peptides for HIV-1 proteases, both wild type and mutant. Secondly, we show an algorithm we developed to predict mutant HIV-1 proteases capable of cleaving a new target substrate peptide, different from the natural targets of HIV-1 protease. The obtained in silico mutant enzymes were analyzed in terms of cleavability and specificity towards the target peptide using the energy-only methodology. We found two mutant proteases as best candidate...

  12. Thiolated pyrimidine nucleotides may interfere thiol groups concentrated at lipid rafts of HIV-1 infected cells.

    Science.gov (United States)

    Kanizsai, Szilvia; Ongrádi, Joseph; Aradi, János; Nagy, Károly

    2014-12-01

    Upon HIV infection, cells become activated and cell surface thiols are present in increased number. Earlier we demonstrated in vitro anti-HIV effect of thiolated pyrimidine nucleotide UD29, which interferes thiol function. To further analyse the redox processes required for HIV-1 entry and infection, toxicity assays were performed using HIV-1 infected monolayer HeLaCD4-LTR/ β-gal cells and suspension H9 T cells treated with several thiolated nucleotide derivatives of UD29. Selective cytotoxicity of thiolated pyrimidines on HIV-1 infected cells were observed. Results indicate that thiolated pyrimidine derivates may interfere with -SH (thiol) groups concentrated in lipid rafts of cell membrane and interacts HIV-1 infected (activated) cells resulting in a selective cytotoxicity of HIV-1 infected cells, and reducing HIV-1 entry.

  13. Design of dimerization inhibitors of HIV-1 aspartic proteinase: A computer-based combinatorial approach

    Science.gov (United States)

    Caflisch, Amedeo; Schramm, Hans J.; Karplus, Martin

    2000-02-01

    Inhibition of dimerization to the active form of the HIV-1 aspartic proteinase (HIV-1 PR) may be a way to decrease the probability of escape mutations for this viral protein. The Multiple Copy Simultaneous Search (MCSS) methodology was used to generate functionality maps for the dimerization interface of HIV-1 PR. The positions of the MCSS minima of 19 organic fragments, once postprocessed to take into account solvation effects, are in good agreement with experimental data on peptides that bind to the interface. The MCSS minima combined with an approach for computational combinatorial ligand design yielded a set of modified HIV-1 PR C-terminal peptides that are similar to known nanomolar inhibitors of HIV-1 PR dimerization. A number of N-substituted 2,5-diketopiperazines are predicted to be potential dimerization inhibitors of HIV-1 PR.

  14. Modeling the HIV-1 Intasome: A Prototype View of the Target of Integrase Inhibitors

    Directory of Open Access Journals (Sweden)

    Robert Craigie

    2010-12-01

    Full Text Available The HIV-1 integrase enzyme is essential for integrating the viral DNA into the host chromosome. Infection is aborted in the absence of integration, making integrase an attractive antiviral target. Recently approved inhibitors of integrase bind tightly to integrase assembled in a nucleoprotein complex with the viral DNA ends (intasome, but have only low affinity for free integrase. High-resolution structures of HIV-1 intasomes are therefore required to understand the detailed mechanisms of inhibition and resistance. Although the structure of the HIV-1 intasome has not yet been determined, the structure of the related prototype foamy virus (PFV intasome was recently solved. A new study [1] exploits the PFV structure to model the HIV-1 intasome. The model provides the most reliable picture to date of the active site region of the HIV-1 intasome and is an important advance in studies of inhibition of this essential HIV-1 enzyme.

  15. HLA Alleles Associated with Slow Progression to AIDS Truly Prefer to Present HIV-1 p24

    DEFF Research Database (Denmark)

    Borghans, J. A.; Molgaard, A.; Boer, R. J. de;

    2007-01-01

    BACKGROUND: The mechanism behind the association between human leukocyte antigen (HLA) molecules and the rate of HIV-1 disease progression is still poorly understood. Recent data suggest that "protective" HLA molecules, i.e. those associated with a low HIV-1 viral load and relatively slow disease...... and effect, we predicted HIV-1 epitopes from the whole genome of HIV-1, and found that protective HLA alleles have a true preference for the p24 Gag protein, while non-protective HLA alleles preferentially target HIV-1 Nef. In line with this, we found a significant negative correlation between the predicted...... affinity of the best-binding p24 epitopes and the relative hazard of HIV-1 disease progression for a large number of HLA molecules. When the epitopes targeted by protective HLA alleles were mapped to the known p24 structure, we found that mutations in these epitopes are likely to disturb the p24 dimer...

  16. Nef alleles from all major HIV-1 clades activate Src-family kinases and enhance HIV-1 replication in an inhibitor-sensitive manner.

    Directory of Open Access Journals (Sweden)

    Purushottam S Narute

    Full Text Available The HIV-1 accessory factor Nef is essential for high-titer viral replication and AIDS progression. Nef function requires interaction with many host cell proteins, including specific members of the Src kinase family. Here we explored whether Src-family kinase activation is a conserved property of Nef alleles from a wide range of primary HIV-1 isolates and their sensitivity to selective pharmacological inhibitors. Representative Nef proteins from the major HIV-1 subtypes A1, A2, B, C, F1, F2, G, H, J and K strongly activated Hck and Lyn as well as c-Src to a lesser extent, demonstrating for the first time that Src-family kinase activation is a highly conserved property of primary M-group HIV-1 Nef isolates. Recently, we identified 4-amino substituted diphenylfuropyrimidines (DFPs that selectively inhibit Nef-dependent activation of Src-family kinases as well as HIV replication. To determine whether DFP compounds exhibit broad-spectrum Nef-dependent antiretroviral activity against HIV-1, we first constructed chimeric forms of the HIV-1 strain NL4-3 expressing each of the primary Nef alleles. The infectivity and replication of these Nef chimeras was indistinguishable from that of wild-type virus in two distinct cell lines (U87MG astroglial cells and CEM-T4 lymphoblasts. Importantly, the 4-aminopropanol and 4-aminobutanol derivatives of DFP potently inhibited the replication of all chimeric forms of HIV-1 in both U87MG and CEM-T4 cells in a Nef-dependent manner. The antiretroviral effects of these compounds correlated with inhibition of Nef-dependent activation of endogenous Src-family kinases in the HIV-infected cells. Our results demonstrate that the activation of Hck, Lyn and c-Src by Nef is highly conserved among all major clades of HIV-1 and that selective targeting of this pathway uniformly inhibits HIV-1 replication.

  17. KI and WU polyomaviruses and CD4+ cell counts in HIV-1-infected patients, Italy.

    Science.gov (United States)

    Babakir-Mina, Muhammed; Ciccozzi, Massimo; Farchi, Francesca; Bergallo, Massimiliano; Cavallo, Rossana; Adorno, Gaspare; Perno, Carlo Federico; Ciotti, Marco

    2010-09-01

    To investigate an association between KI and WU polyomavirus (KIPyV and WUPyV) infections and CD4+ cell counts, we tested HIV-1-positive patients and blood donors. No association was found between cell counts and virus infections in HIV-1-positive patients. Frequency of KIPyV infection was similar for both groups. WUPyV was more frequent in HIV-1-positive patients.

  18. Multi-Faceted Post-Transcriptional Functions of HIV-1 Rev

    Directory of Open Access Journals (Sweden)

    Kuan-Teh Jeang

    2012-07-01

    Full Text Available Post-transcriptional regulation of HIV-1 gene expression is largely governed by the activities of the viral Rev protein. In this minireview, the multiple post-transcriptional activities of Rev in the export of partially spliced and unspliced HIV-1 RNAs from the nucleus to the cytoplasm, in the translation of HIV-1 transcripts, and in the packaging of viral genomic RNAs are reviewed in brief.

  19. Mycobacterium avium complex augments macrophage HIV-1 production and increases CCR5 expression

    OpenAIRE

    1998-01-01

    Infection with HIV-1 results in pronounced immune suppression and susceptibility to opportunistic infections (OI). Reciprocally, OI augment HIV-1 replication. As we have shown for Mycobacterium avium complex (MAC) and Pneumocystis carinii, macrophages infected with opportunistic pathogens and within lymphoid tissues containing OI, exhibit striking levels of viral replication. To explore potential underlying mechanisms for increased HIV-1 replication associated with coinfection, blood monocyte...

  20. Sequence and structure requirements for specific recognition of HIV-1 TAR and DIS RNA by the HIV-1 Vif protein.

    Science.gov (United States)

    Freisz, Séverine; Mezher, Joelle; Hafirassou, Lamine; Wolff, Philippe; Nominé, Yves; Romier, Christophe; Dumas, Philippe; Ennifar, Eric

    2012-07-01

    The HIV-1 Vif protein plays an essential role in the regulation of the infectivity of HIV-1 virion and in vivo pathogenesis. Vif neutralizes the human DNA-editing enzyme APOBEC3 protein, an antiretroviral cellular factor from the innate immune system, allowing the virus to escape the host defence system. It was shown that Vif is packaged into viral particles through specific interactions with the viral genomic RNA. Conserved and structured sequences from the 5'-noncoding region, such as the Tat-responsive element (TAR) or the genomic RNA dimerization initiation site (DIS), are primary binding sites for Vif. In the present study we used isothermal titration calorimetry to investigate sequence and structure determinants important for Vif binding to short viral RNA corresponding to TAR and DIS stem-loops. We showed that Vif specifically binds TAR and DIS in the low nanomolar range. In addition, Vif primarily binds the TAR UCU bulge, but not the apical loop. Determinants for Vif binding to the DIS loop-loop complex are likely more complex and involve the self-complementary loop together with the upper part of the stem. These results suggest that Tat-TAR inhibitors or DIS small molecule binders might be also effective to disturb Vif-TAR and Vif-DIS binding in order to reduce Vif packaging into virions.

  1. Diminished representation of HIV-1 variants containing select drug resistance-conferring mutations in primary HIV-1 infection.

    Science.gov (United States)

    Turner, Dan; Brenner, Bluma; Routy, Jean-Pierre; Moisi, Daniela; Rosberger, Zeev; Roger, Michel; Wainberg, Mark A

    2004-12-15

    This study compared the incidence of HIV-1 variants harboring mutations conferring resistance to thymidine analogues, ie, thymidine analogue mutations (TAMs), nonnucleoside reverse transcriptase (RT) inhibitors (NNMs), lamivudine (3TC) (ie, M184V), and protease inhibitors (PIs) acquired in primary HIV infection (PHI) (n = 59) to their observed prevalence in a corresponding potential transmitter (PT) population of persons harboring resistant infections (n = 380). Both of these populations in the context of this cohort analysis possessed similar demographics. Whereas the frequencies of observed TAMs, NNMs, M184V, and protease-associated mutations (PRAMs) were similar in the PT groups, the prevalence of M184V and major PI mutations were significantly lower in the PHI group (PHI/PT ratios of 0.14 and 0.39, respectively). There was a decreased prevalence in the PHI population of resistant viruses co-expressing NNMs or TAMs with M184V compared with viruses that harbored NNMs or TAMs in the absence of M184V (P < 0.0001). It was also observed that individuals in the PT subgroups who harbored RT mutations or PRAMs with M184V had lower levels of plasma viremia than individuals who lacked M184V (P < 0.05). These findings suggest that both decreased viremia and viral fitness in the case of M184V-containing HIV-1 variants may impact on viral transmissibility.

  2. Different pattern of immunoglobulin gene usage by HIV-1 compared to non-HIV-1 antibodies derived from the same infected subject.

    Directory of Open Access Journals (Sweden)

    Liuzhe Li

    Full Text Available A biased usage of immunoglobulin (Ig genes is observed in human anti-HIV-1 monoclonal antibodies (mAbs resulting probably from compensation to reduced usage of the VH3 family genes, while the other alternative suggests that this bias usage is due to antigen requirements. If the antigen structure is responsible for the preferential usage of particular Ig genes, it may have certain implications for HIV vaccine development by the targeting of particular Ig gene-encoded B cell receptors to induce neutralizing anti-HIV-1 antibodies. To address this issue, we have produced HIV-1 specific and non-HIV-1 mAbs from an infected individual and analyzed the Ig gene usage. Green-fluorescence labeled virus-like particles (VLP expressing HIV-1 envelope (Env proteins of JRFL and BaL and control VLPs (without Env were used to select single B cells for the production of 68 recombinant mAbs. Ten of these mAbs were HIV-1 Env specific with neutralizing activity against V3 and the CD4 binding site, as well as non-neutralizing mAbs to gp41. The remaining 58 mAbs were non-HIV-1 Env mAbs with undefined specificities. Analysis revealed that biased usage of Ig genes was restricted only to anti-HIV-1 but not to non-HIV-1 mAbs. The VH1 family genes were dominantly used, followed by VH3, VH4, and VH5 among anti-HIV-1 mAbs, while non-HIV-1 specific mAbs preferentially used VH3 family genes, followed by VH4, VH1 and VH5 families in a pattern identical to Abs derived from healthy individuals. This observation suggests that the biased usage of Ig genes by anti-HIV-1 mAbs is driven by structural requirements of the virus antigens rather than by compensation to any depletion of VH3 B cells due to autoreactive mechanisms, according to the gp120 superantigen hypothesis.

  3. Schistosomiasis and HIV-1 infection in rural Zimbabwe: effect of treatment of schistosomiasis on CD4 cell count and plasma HIV-1 RNA load

    DEFF Research Database (Denmark)

    Kallestrup, Per; Zinyama, Rutendo; Gomo, Exnevia;

    2005-01-01

    To determine whether treatment of schistosomiasis has an effect on the course of human immunodeficiency virus type 1 (HIV-1) infection, individuals with schistosomiasis and with or without HIV-1 infection were randomized to receive praziquantel treatment at inclusion or after a delay of 3 months......; 287 participants were included in the study, and 227 (79%) were followed up. Among the 130 participants who were coinfected, those who received early treatment (n=64) had a significantly lower increase in plasma HIV-1 RNA load than did those who received delayed treatment (n=66) (P...

  4. Pandemic HIV-1 Vpu overcomes intrinsic herd immunity mediated by tetherin.

    Science.gov (United States)

    Iwami, Shingo; Sato, Kei; Morita, Satoru; Inaba, Hisashi; Kobayashi, Tomoko; Takeuchi, Junko S; Kimura, Yuichi; Misawa, Naoko; Ren, Fengrong; Iwasa, Yoh; Aihara, Kazuyuki; Koyanagi, Yoshio

    2015-07-17

    Among the four groups of HIV-1 (M, N, O, and P), HIV-1M alone is pandemic and has rapidly expanded across the world. However, why HIV-1M has caused a devastating pandemic while the other groups remain contained is unclear. Interestingly, only HIV-1M Vpu, a viral protein, can robustly counteract human tetherin, which tethers budding virions. Therefore, we hypothesize that this property of HIV-1M Vpu facilitates human-to-human viral transmission. Adopting a multilayered experimental-mathematical approach, we demonstrate that HIV-1M Vpu confers a 2.38-fold increase in the prevalence of HIV-1 transmission. When Vpu activity is lost, protected human populations emerge (i.e., intrinsic herd immunity develops) through the anti-viral effect of tetherin. We also reveal that all Vpus of transmitted/founder HIV-1M viruses maintain anti-tetherin activity. These findings indicate that tetherin plays the role of a host restriction factor, providing 'intrinsic herd immunity', whereas Vpu has evolved in HIV-1M as a tetherin antagonist.

  5. HIV-1 Vpr induces interferon-stimulated genes in human monocyte-derived macrophages.

    Directory of Open Access Journals (Sweden)

    Muhammad Atif Zahoor

    Full Text Available Macrophages act as reservoirs of human immunodeficiency virus type 1 (HIV-1 and play an important role in its transmission to other cells. HIV-1 Vpr is a multi-functional protein involved in HIV-1 replication and pathogenesis; however, its exact role in HIV-1-infected human macrophages remains poorly understood. In this study, we used a microarray approach to explore the effects of HIV-1 Vpr on the transcriptional profile of human monocyte-derived macrophages (MDMs. More than 500 genes, mainly those involved in the innate immune response, the type I interferon pathway, cytokine production, and signal transduction, were differentially regulated (fold change >2.0 after infection with a recombinant adenovirus expressing HIV-1 Vpr protein. The differential expression profiles of select interferon-stimulated genes (ISGs and genes involved in the innate immune response, including STAT1, IRF7, MX1, MX2, ISG15, ISG20, IFIT1, IFIT2, IFIT3, IFI27, IFI44L, APOBEC3A, DDX58 (RIG-I, TNFSF10 (TRAIL, and RSAD2 (viperin were confirmed by real-time quantitative PCR and were consistent with the microarray data. In addition, at the post-translational level, HIV-1 Vpr induced the phosphorylation of STAT1 at tyrosine 701 in human MDMs. These results demonstrate that HIV-1 Vpr leads to the induction of ISGs and expand the current understanding of the function of Vpr and its role in HIV-1 immune pathogenesis.

  6. Adenosine deaminase acting on RNA-1 (ADAR1 inhibits HIV-1 replication in human alveolar macrophages.

    Directory of Open Access Journals (Sweden)

    Michael D Weiden

    Full Text Available While exploring the effects of aerosol IFN-γ treatment in HIV-1/tuberculosis co-infected patients, we observed A to G mutations in HIV-1 envelope sequences derived from bronchoalveolar lavage (BAL of aerosol IFN-γ-treated patients and induction of adenosine deaminase acting on RNA 1 (ADAR1 in the BAL cells. IFN-γ induced ADAR1 expression in monocyte-derived macrophages (MDM but not T cells. ADAR1 siRNA knockdown induced HIV-1 expression in BAL cells of four HIV-1 infected patients on antiretroviral therapy. Similar results were obtained in MDM that were HIV-1 infected in vitro. Over-expression of ADAR1 in transformed macrophages inhibited HIV-1 viral replication but not viral transcription measured by nuclear run-on, suggesting that ADAR1 acts post-transcriptionally. The A to G hyper-mutation pattern observed in ADAR1 over-expressing cells in vitro was similar to that found in the lungs of HIV-1 infected patients treated with aerosol IFN-γ suggesting the model accurately represented alveolar macrophages. Together, these results indicate that ADAR1 restricts HIV-1 replication post-transcriptionally in macrophages harboring HIV-1 provirus. ADAR1 may therefore contribute to viral latency in macrophages.

  7. HIV-1 production is specifically associated with human NMT1 long form in human NMT isozymes.

    Science.gov (United States)

    Takamune, Nobutoki; Gota, Kayoko; Misumi, Shogo; Tanaka, Kenzo; Okinaka, Shigetaka; Shoji, Shozo

    2008-02-01

    The N-myristoylation of the N-terminal of human immunodeficiency virus type-1 (HIV-1) Pr55(gag) by human N-myristoyltransferase (hNMT) is a prerequisite modification for HIV-1 production. hNMT consists of multiple isozymes encoded by hNMT1 and hNMT2. The hNMT1 isozyme consists of long, medium, and short forms. Here, we investigated which isozyme is crucial for HIV-1 production. Human embryonic kidney (HEK) 293 cells transfected with infectious HIV-1 vectors were used as models of HIV-1-infected cells in this study. The significant reduction in HIV-1 production and the failure of the specific localization of Pr55(gag) in a detergent-resistant membrane fraction were dependent on the knockdown of the different forms of the hNMT1 isozyme but not of the hNMT2 isozyme. Additionally, the coexpression of an inactive mutant hNMT1 isozyme, namely the hNMT1 long form (hNMT1(L)), but not that of other hNMT mutants resulted in a significant reduction in HIV-1 production. These results strongly suggest that HIV-1 production is specifically associated with hNMT1, particularly hNMT1(L), but not with hNMT2 in vivo, contributing to the understanding of a step in HIV-1 replication.

  8. The kidney as a reservoir for HIV-1 after renal transplantation.

    Science.gov (United States)

    Canaud, Guillaume; Dejucq-Rainsford, Nathalie; Avettand-Fenoël, Véronique; Viard, Jean-Paul; Anglicheau, Dany; Bienaimé, Frank; Muorah, Mordi; Galmiche, Louise; Gribouval, Olivier; Noël, Laure-Helene; Satie, Anne-Pascale; Martinez, Frank; Sberro-Soussan, Rebecca; Scemla, Anne; Gubler, Marie-Claire; Friedlander, Gérard; Antignac, Corinne; Timsit, Marc-Olivier; Onetti Muda, Andrea; Terzi, Fabiola; Rouzioux, Christine; Legendre, Christophe

    2014-02-01

    Since the recent publication of data showing favorable outcomes for patients with HIV-1 and ESRD, kidney transplantation has become a therapeutic option in this population. However, reports have documented unexplained reduced allograft survival in these patients. We hypothesized that the unrecognized infection of the transplanted kidney by HIV-1 can compromise long-term allograft function. Using electron microscopy and molecular biology, we examined protocol renal transplant biopsies from 19 recipients with HIV-1 who did not have detectable levels of plasma HIV-1 RNA at transplantation. We found that HIV-1 infected the kidney allograft in 68% of these patients. Notably, HIV-1 infection was detected in either podocytes predominately (38% of recipients) or tubular cells only (62% of recipients). Podocyte infection associated with podocyte apoptosis and loss of differentiation markers as well as a faster decline in allograft function compared with tubular cell infection. In allografts with tubular cell infection, epithelial cells of the proximal convoluted tubules frequently contained abnormal mitochondria, and both patients who developed features of subclinical acute cellular rejection had allografts with tubular cell infection. Finally, we provide a novel noninvasive test for determining HIV-1 infection of the kidney allograft by measuring HIV-1 DNA and RNA levels in patients' urine. In conclusion, HIV-1 can infect kidney allografts after transplantation despite undetectable viremia, and this infection might influence graft outcome.

  9. Potent Intratype Neutralizing Activity Distinguishes Human Immunodeficiency Virus Type 2 (HIV-2) from HIV-1

    OpenAIRE

    Özkaya Şahin, Gülşen; Holmgren, Birgitta; da Silva, Zacarias; Nielsen, Jens; Nowroozalizadeh, Salma; Esbjörnsson, Joakim; Månsson, Fredrik; Andersson, Sören; Norrgren, Hans; Aaby, Peter; Jansson, Marianne; Fenyö, Eva Maria

    2012-01-01

    HIV-2 has a lower pathogenicity and transmission rate than HIV-1. Neutralizing antibodies could be contributing to these observations. Here we explored side by side the potency and breadth of intratype and intertype neutralizing activity (NAc) in plasma of 20 HIV-1-, 20 HIV-2-, and 11 dually HIV-1/2 (HIV-D)-seropositive individuals from Guinea-Bissau, West Africa. Panels of primary isolates, five HIV-1 and five HIV-2 isolates, were tested in a plaque reduction assay using U87.CD4-CCR5 cells a...

  10. The Kidney as a Reservoir for HIV-1 after Renal Transplantation

    Science.gov (United States)

    Dejucq-Rainsford, Nathalie; Avettand-Fenoël, Véronique; Viard, Jean-Paul; Anglicheau, Dany; Bienaimé, Frank; Muorah, Mordi; Galmiche, Louise; Gribouval, Olivier; Noël, Laure-Helene; Satie, Anne-Pascale; Martinez, Frank; Sberro-Soussan, Rebecca; Scemla, Anne; Gubler, Marie-Claire; Friedlander, Gérard; Antignac, Corinne; Timsit, Marc-Olivier; Onetti Muda, Andrea; Terzi, Fabiola; Rouzioux, Christine; Legendre, Christophe

    2014-01-01

    Since the recent publication of data showing favorable outcomes for patients with HIV-1 and ESRD, kidney transplantation has become a therapeutic option in this population. However, reports have documented unexplained reduced allograft survival in these patients. We hypothesized that the unrecognized infection of the transplanted kidney by HIV-1 can compromise long-term allograft function. Using electron microscopy and molecular biology, we examined protocol renal transplant biopsies from 19 recipients with HIV-1 who did not have detectable levels of plasma HIV-1 RNA at transplantation. We found that HIV-1 infected the kidney allograft in 68% of these patients. Notably, HIV-1 infection was detected in either podocytes predominately (38% of recipients) or tubular cells only (62% of recipients). Podocyte infection associated with podocyte apoptosis and loss of differentiation markers as well as a faster decline in allograft function compared with tubular cell infection. In allografts with tubular cell infection, epithelial cells of the proximal convoluted tubules frequently contained abnormal mitochondria, and both patients who developed features of subclinical acute cellular rejection had allografts with tubular cell infection. Finally, we provide a novel noninvasive test for determining HIV-1 infection of the kidney allograft by measuring HIV-1 DNA and RNA levels in patients’ urine. In conclusion, HIV-1 can infect kidney allografts after transplantation despite undetectable viremia, and this infection might influence graft outcome. PMID:24309185

  11. Monoclonal Antibodies Recognizing HIV-1 gp41 Could Inhibit Env-Mediated Syncytium Formation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Geng; CHEN Yinghua

    2005-01-01

    Some monoclonal antibodies (mAbs) could inhibit infection by HIV-1. In this study, four mAbs against HIV-1 gp41 were prepared in mice. All four mAbs could bind to the recombinant soluble gp41 and recognize the native envelope glycoprotein gp160 expressed on the HIV-Env+ CHO-WT cell in flow cytometry analysis. Interestingly, the results show that all four mAbs purified by affinity chromatography could inhibit HIV-1 Env-mediated membrane fusion (syncytium formation) by 40%-60% at 10 μg/mL, which implies potential inhibitory activities against HIV-1.

  12. Escherichia coli surface display of single-chain antibody VRC01 against HIV-1 infection

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lin-Xu [Nebraska Center for Virology, Lincoln, NE (United States); School of Biological Sciences, University of Nebraska—Lincoln, Lincoln, NE 68583 (United States); Mellon, Michael [Nebraska Center for Virology, Lincoln, NE (United States); School of Veterinary Medicine and Biomedical Sciences, Lincoln, NE (United States); Bowder, Dane [Nebraska Center for Virology, Lincoln, NE (United States); School of Biological Sciences, University of Nebraska—Lincoln, Lincoln, NE 68583 (United States); Quinn, Meghan [Nebraska Center for Virology, Lincoln, NE (United States); School of Veterinary Medicine and Biomedical Sciences, Lincoln, NE (United States); Shea, Danielle; Wood, Charles [Nebraska Center for Virology, Lincoln, NE (United States); School of Biological Sciences, University of Nebraska—Lincoln, Lincoln, NE 68583 (United States); Xiang, Shi-Hua, E-mail: sxiang2@unl.edu [Nebraska Center for Virology, Lincoln, NE (United States); School of Veterinary Medicine and Biomedical Sciences, Lincoln, NE (United States)

    2015-01-15

    Human immunodeficiency virus type 1 (HIV-1) transmission and infection occur mainly via the mucosal surfaces. The commensal bacteria residing in these surfaces can potentially be employed as a vehicle for delivering inhibitors to prevent HIV-1 infection. In this study, we have employed a bacteria-based strategy to display a broadly neutralizing antibody VRC01, which could potentially be used to prevent HIV-1 infection. The VRC01 antibody mimics CD4-binding to gp120 and has broadly neutralization activities against HIV-1. We have designed a construct that can express the fusion peptide of the scFv-VRC01 antibody together with the autotransporter β-barrel domain of IgAP gene from Neisseria gonorrhoeae, which enabled surface display of the antibody molecule. Our results indicate that the scFv-VRC01 antibody molecule was displayed on the surface of the bacteria as demonstrated by flow cytometry and immunofluorescence microscopy. The engineered bacteria can capture HIV-1 particles via surface-binding and inhibit HIV-1 infection in cell culture. - Highlights: • Designed single-chain VRC01 antibody was demonstrated to bind HIV-1 envelope gp120. • Single-chain VRC01 antibody was successfully displayed on the surface of E. coli. • Engineered bacteria can absorb HIV-1 particles and prevent HIV-1 infection in cell culture.

  13. Inhibition of HIV-1 replication in alveolar macrophages by adenovirus gene transfer vectors.

    Science.gov (United States)

    Rice, Joshua; Connor, Ruth; Worgall, Stefan; Moore, John P; Leopold, Philip L; Kaner, Robert J; Crystal, Ronald G

    2002-08-01

    To assess the hypothesis that infection of alveolar macrophages (AM) with adenovirus (Ad) gene transfer vectors might prevent subsequent human immunodeficiency virus (HIV)-1 replication in AM, AM isolated from normal volunteers were infected with increasing doses of first generation (E1(-)) Ad vectors, followed 72 h later by infection with HIV-1(JRFL), an R5/M-tropic strain that preferentially uses the CCR5 coreceptor. As a measure of HIV-1 replication, p24 Ag was quantified by enzyme-linked imunosorbent assay in supernatants on Days 4 to 14 after HIV-1infection. Pretreatment of the AM with an Ad vector resulted in a dose- and time-dependent suppression of subsequent HIV-1 replication. The Ad vector inhibition of HIV-1 replication was independent of the transgene in the Ad vector expression cassette and E4 genes in the Ad backbone. Moreover, it did not appear to be secondary to a soluble factor released by the AM, nor was it overridden by the concomitant transfer of the CCR5 or CXCR4 receptors to the AM before HIV-1 infection. These observations have implications regarding pulmonary host responses associated with HIV-1 infection, as well as possibly uncovering new therapeutic strategies against HIV-1 infection.

  14. Mangiferin, an Anti-HIV-1 Agent Targeting Protease and Effective against Resistant Strains

    OpenAIRE

    Rui-Rui Wang; Yue-Dong Gao; Chun-Hui Ma; Xing-Jie Zhang; Cheng-Gang Huang; Jing-Fei Huang; Yong-Tang Zheng

    2011-01-01

    The anti-HIV-1 activity of mangiferin was evaluated. Mangiferin can inhibit HIV-1ⅢB induced syncytium formation at non-cytotoxic concentrations, with a 50% effective concentration (EC50) at 16.90 μM and a therapeutic index (TI) above 140. Mangiferin also showed good activities in other laboratory-derived strains, clinically isolated strains and resistant HIV-1 strains. Mechanism studies revealed that mangiferin might inhibit the HIV-1 protease, but is still effective against HIV peptidic prot...

  15. Protective efficacy of a global HIV-1 mosaic vaccine against heterologous SHIV challenges in rhesus monkeys.

    Science.gov (United States)

    Barouch, Dan H; Stephenson, Kathryn E; Borducchi, Erica N; Smith, Kaitlin; Stanley, Kelly; McNally, Anna G; Liu, Jinyan; Abbink, Peter; Maxfield, Lori F; Seaman, Michael S; Dugast, Anne-Sophie; Alter, Galit; Ferguson, Melissa; Li, Wenjun; Earl, Patricia L; Moss, Bernard; Giorgi, Elena E; Szinger, James J; Eller, Leigh Anne; Billings, Erik A; Rao, Mangala; Tovanabutra, Sodsai; Sanders-Buell, Eric; Weijtens, Mo; Pau, Maria G; Schuitemaker, Hanneke; Robb, Merlin L; Kim, Jerome H; Korber, Bette T; Michael, Nelson L

    2013-10-24

    The global diversity of HIV-1 represents a critical challenge facing HIV-1 vaccine development. HIV-1 mosaic antigens are bioinformatically optimized immunogens designed for improved coverage of HIV-1 diversity. However, the protective efficacy of such global HIV-1 vaccine antigens has not previously been evaluated. Here, we demonstrate the capacity of bivalent HIV-1 mosaic antigens to protect rhesus monkeys against acquisition of infection following heterologous challenges with the difficult-to-neutralize simian-human immunodeficiency virus SHIV-SF162P3. Adenovirus/poxvirus and adenovirus/adenovirus vector-based vaccines expressing HIV-1 mosaic Env, Gag, and Pol afforded a significant reduction in the per-exposure acquisition risk following repetitive, intrarectal SHIV-SF162P3 challenges. Protection against acquisition of infection correlated with vaccine-elicited binding, neutralizing, and functional nonneutralizing antibodies, suggesting that the coordinated activity of multiple antibody functions may contribute to protection against difficult-to-neutralize viruses. These data demonstrate the protective efficacy of HIV-1 mosaic antigens and suggest a potential strategy for the development of a global HIV-1 vaccine. PAPERCLIP:

  16. Nine Crystal Structures Determine the Substrate Envelope of the MDR HIV-1 Protease

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhigang; Wang, Yong; Brunzelle, Joseph; Kovari, Iulia A.; Kovari, Ladislau C. (WSU-MED); (NWU)

    2012-03-27

    Under drug selection pressure, emerging mutations render HIV-1 protease drug resistant, leading to the therapy failure in anti-HIV treatment. It is known that nine substrate cleavage site peptides bind to wild type (WT) HIV-1 protease in a conserved pattern. However, how the multidrug-resistant (MDR) HIV-1 protease binds to the substrate cleavage site peptides is yet to be determined. MDR769 HIV-1 protease (resistant mutations at residues 10, 36, 46, 54, 62, 63, 71, 82, 84, and 90) was selected for present study to understand the binding to its natural substrates. MDR769 HIV-1 protease was co-crystallized with nine substrate cleavage site hepta-peptides. Crystallographic studies show that MDR769 HIV-1 protease has an expanded substrate envelope with wide open flaps. Furthermore, ligand binding energy calculations indicate weaker binding in MDR769 HIV-1 protease-substrate complexes. These results help in designing the next generation of HIV-1 protease inhibitors by targeting the MDR HIV-1 protease.

  17. 新疆紫草提取物抗HIV-1体外活性研究(Ⅱ)%Activity of extracts from Arnebia Euchroma (Royle) Johnst. to HIV-1 key enzymes in vitro.

    Institute of Scientific and Technical Information of China (English)

    买尔旦·马合木提; 古丽仙·胡加; 秦冬梅

    2009-01-01

    目的:研究新疆紫草水溶性组分Ⅰ、Ⅱ、Ⅲ、Ⅳ对HIV-1 3个关键酶的体外活性.方法: 分别选用HIV-1整合酶(HIV-1 ingrase,HIV-1 IN),HIV-1蛋白酶 (HIV-1 protease ,HIV-1 PR) ,HIV-1逆转录酶(HIV-1 reverse transcriptase,HIV-1 RT)体外药效筛选模型,观察组分Ⅰ、Ⅱ、Ⅲ和Ⅳ对以上酶的抑制作用.结果: 新疆紫草水溶性组分Ⅰ、Ⅱ、Ⅲ和Ⅳ对HIV-1 IN具有一定的抑制活性,50%有效浓度(EC50)分别为2.21、 14.71、5.71和66.08 μg/ml.组分Ⅰ对HIV-1 RT的抑制活性小,EC50为5.63 μg/ml.结论: 新疆紫草水溶性提取物对HIV-1 IN具有抑制活性,对HIV-1 PR均无抑制活性.

  18. Molecular Characterization of Mexican HIV-1 Vif Sequences.

    Science.gov (United States)

    Guerra-Palomares, Sandra E; Hernandez-Sanchez, Pedro G; Esparza-Perez, Mario A; Arguello, J Rafael; Noyola, Daniel E; Garcia-Sepulveda, Christian A

    2016-03-01

    The viral infectivity factor (Vif) is an HIV accessory protein that counteracts host antiviral proteins of the APOBEC3 family. Accumulating evidence highlights the pivotal role that accessory HIV proteins have on disease pathogenesis, a fact that has made them targets of interest for novel therapeutic and preventive strategies. Little is known about Vif sequence diversity outside of African or white populations. Mexico is home to Americas' third largest HIV-affected population and Mexican Hispanics represent an ever-increasing U.S. minority. This study provides a detailed analysis of the diversity seen in 77 Mexican Vif protein sequences. Phylogenetic analysis shows that most sequences cluster with HIV-1 subtype B, while less than 10% exhibit greater similarity to subtype D and A subtypes. Although most functional motifs are conserved among the Mexican sequences, substantial diversity was seen in some APOBEC binding sites, the nuclear localization inhibitory signal, and the CBFβ interaction sites.

  19. HIV-1 Polymorphism: a Challenge for Vaccine Development - A Review

    Directory of Open Access Journals (Sweden)

    Morgado MG

    2002-01-01

    Full Text Available The perspective for the development of anti-HIV/AIDS vaccines became a target sought by several research groups and pharmaceutical companies. However, the complex virus biology in addition to a striking genetic variability and the limited understanding of the immunological correlates of protection have made this an enormous scientific challenge not overcome so far. In this review we presented an updating of HIV-1 subtypes and recombinant viruses circulating in South American countries, focusing mainly on Brazil, as one of the challenges for HIV vaccine development. Moreover, we discussed the importance of stimulating developing countries to participate in the process of vaccine evaluation, not only testing vaccines according to already defined protocols, but also working together with them, in order to take into consideration their local information on virus diversity and host genetic background relevant for the vaccine development and testing, as well as including local virus based reagents to evaluate the immunogenicity of the candidate vaccines.

  20. HIV-1 integrase inhibitor resistance and its clinical implications.

    Science.gov (United States)

    Blanco, Jose-Luis; Varghese, Vici; Rhee, Soo-Yon; Gatell, Jose M; Shafer, Robert W

    2011-05-01

    With the approval in 2007 of the first integrase inhibitor (INI), raltegravir, clinicians became better able to suppress virus replication in patients infected with human immunodeficiency virus type 1 (HIV-1) who were harboring many of the most highly drug-resistant viruses. Raltegravir also provided clinicians with additional options for first-line therapy and for the simplification of regimens in patients with stable virological suppression. Two additional INIs in advanced clinical development-elvitegravir and S/GSK1349572-may prove equally versatile. However, the INIs have a relatively low genetic barrier to resistance in that 1 or 2 mutations are capable of causing marked reductions in susceptibility to raltegravir and elvitegravir, the most well-studied INIs. This perspective reviews the genetic mechanisms of INI resistance and their implications for initial INI therapy, the treatment of antiretroviral-experienced patients, and regimen simplification.

  1. Dynamic Post-Transcriptional Regulation of HIV-1 Gene Expression

    Science.gov (United States)

    Kula, Anna; Marcello, Alessandro

    2012-01-01

    Gene expression of the human immunodeficiency virus type 1 (HIV-1) is a highly regulated process. Basal transcription of the integrated provirus generates early transcripts that encode for the viral products Tat and Rev. Tat promotes the elongation of RNA polymerase while Rev mediates the nuclear export of viral RNAs that contain the Rev-responsive RNA element (RRE). These RNAs are exported from the nucleus to allow expression of Gag-Pol and Env proteins and for the production of full-length genomic RNAs. A balance exists between completely processed mRNAs and RRE-containing RNAs. Rev functions as an adaptor that recruits cellular factors to re-direct singly spliced and unspliced viral RNAs to nuclear export. The aim of this review is to address the dynamic regulation of this post-transcriptional pathway in light of recent findings that implicate several novel cellular cofactors of Rev function. PMID:24832221

  2. Dynamic Post-Transcriptional Regulation of HIV-1 Gene Expression

    Directory of Open Access Journals (Sweden)

    Alessandro Marcello

    2012-07-01

    Full Text Available Gene expression of the human immunodeficiency virus type 1 (HIV-1 is a highly regulated process. Basal transcription of the integrated provirus generates early transcripts that encode for the viral products Tat and Rev. Tat promotes the elongation of RNA polymerase while Rev mediates the nuclear export of viral RNAs that contain the Rev-responsive RNA element (RRE. These RNAs are exported from the nucleus to allow expression of Gag-Pol and Env proteins and for the production of full-length genomic RNAs. A balance exists between completely processed mRNAs and RRE-containing RNAs. Rev functions as an adaptor that recruits cellular factors to re-direct singly spliced and unspliced viral RNAs to nuclear export. The aim of this review is to address the dynamic regulation of this post-transcriptional pathway in light of recent findings that implicate several novel cellular cofactors of Rev function.

  3. RNA structure. Structure of the HIV-1 RNA packaging signal.

    Science.gov (United States)

    Keane, Sarah C; Heng, Xiao; Lu, Kun; Kharytonchyk, Siarhei; Ramakrishnan, Venkateswaran; Carter, Gregory; Barton, Shawn; Hosic, Azra; Florwick, Alyssa; Santos, Justin; Bolden, Nicholas C; McCowin, Sayo; Case, David A; Johnson, Bruce A; Salemi, Marco; Telesnitsky, Alice; Summers, Michael F

    2015-05-22

    The 5' leader of the HIV-1 genome contains conserved elements that direct selective packaging of the unspliced, dimeric viral RNA into assembling particles. By using a (2)H-edited nuclear magnetic resonance (NMR) approach, we determined the structure of a 155-nucleotide region of the leader that is independently capable of directing packaging (core encapsidation signal; Ψ(CES)). The RNA adopts an unexpected tandem three-way junction structure, in which residues of the major splice donor and translation initiation sites are sequestered by long-range base pairing and guanosines essential for both packaging and high-affinity binding to the cognate Gag protein are exposed in helical junctions. The structure reveals how translation is attenuated, Gag binding promoted, and unspliced dimeric genomes selected, by the RNA conformer that directs packaging.

  4. Inhibition of HIV-1 Reverse Transcriptase Dimerization by Small Molecules.

    Science.gov (United States)

    Tintori, Cristina; Corona, Angela; Esposito, Francesca; Brai, Annalaura; Grandi, Nicole; Ceresola, Elisa Rita; Clementi, Massimo; Canducci, Filippo; Tramontano, Enzo; Botta, Maurizio

    2016-04-15

    Because HIV-1 reverse transcriptase is an enzyme whose catalytic activity depends on its heterodimeric structure, this system could be a target for inhibitors that perturb the interactions between the protein subunits, p51 and p66. We previously demonstrated that the small molecule MAS0 reduced the association of the two RT subunits and simultaneously inhibited both the polymerase and ribonuclease H activities. In this study, some analogues of MAS0 were rationally selected by docking studies and evaluated in vitro for their ability to disrupt dimeric assembly. Two inhibitors were identified with improved activity compared to MAS0. This study lays the basis for the rational design of more potent inhibitors of RT dimerization.

  5. Design of second generation HIV-1 integrase inhibitors.

    Science.gov (United States)

    Deng, Jinxia; Dayam, Raveendra; Al-Mawsawi, Laith Q; Neamati, Nouri

    2007-01-01

    The prospect of HIV-1 integrase (IN) as a therapeutically viable retroviral drug target is on the verge of realization. The observed preclinical and clinical performance of beta-diketo containing and naphthyridine carboxamide compounds provides direct proof for the clinical application of IN inhibition. These validated lead compounds are useful in the design and development of second generation IN inhibitors. The results from preclinical and clinical studies on the first generation IN inhibitors reiterate a demand for novel second generation inhibitors with improved pharmacokinetic and metabolic properties. Pharmacophore-based drug design techniques facilitate the discovery of novel compounds on the basis of validated lead compounds specific for a drug target. In this article we have comprehensively reviewed the application of pharmacophore-based drug design methods in the field of IN inhibitor discovery.

  6. Reconstructing the temporal progression of HIV-1 immune response pathways

    Science.gov (United States)

    Jain, Siddhartha; Arrais, Joel; Venkatachari, Narasimhan J.; Ayyavoo, Velpandi; Bar-Joseph, Ziv

    2016-01-01

    Motivation: Most methods for reconstructing response networks from high throughput data generate static models which cannot distinguish between early and late response stages. Results: We present TimePath, a new method that integrates time series and static datasets to reconstruct dynamic models of host response to stimulus. TimePath uses an Integer Programming formulation to select a subset of pathways that, together, explain the observed dynamic responses. Applying TimePath to study human response to HIV-1 led to accurate reconstruction of several known regulatory and signaling pathways and to novel mechanistic insights. We experimentally validated several of TimePaths’ predictions highlighting the usefulness of temporal models. Availability and Implementation: Data, Supplementary text and the TimePath software are available from http://sb.cs.cmu.edu/timepath Contact: zivbj@cs.cmu.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:27307624

  7. HIV-1 quasispecies delineation by tag linkage deep sequencing.

    Science.gov (United States)

    Wu, Nicholas C; De La Cruz, Justin; Al-Mawsawi, Laith Q; Olson, C Anders; Qi, Hangfei; Luan, Harding H; Nguyen, Nguyen; Du, Yushen; Le, Shuai; Wu, Ting-Ting; Li, Xinmin; Lewis, Martha J; Yang, Otto O; Sun, Ren

    2014-01-01

    Trade-offs between throughput, read length, and error rates in high-throughput sequencing limit certain applications such as monitoring viral quasispecies. Here, we describe a molecular-based tag linkage method that allows assemblage of short sequence reads into long DNA fragments. It enables haplotype phasing with high accuracy and sensitivity to interrogate individual viral sequences in a quasispecies. This approach is demonstrated to deduce ∼ 2000 unique 1.3 kb viral sequences from HIV-1 quasispecies in vivo and after passaging ex vivo with a detection limit of ∼ 0.005% to ∼ 0.001%. Reproducibility of the method is validated quantitatively and qualitatively by a technical replicate. This approach can improve monitoring of the genetic architecture and evolution dynamics in any quasispecies population.

  8. Forgiveness of non-adherence to HIV-1 antiretroviral therapy.

    Science.gov (United States)

    Shuter, Jonathan

    2008-04-01

    Superior adherence to HIV-1 antiretroviral therapy is a mainstay of successful HIV management. Studies performed in the early era of highly active antiretroviral therapy demonstrated the need for > or =95% adherence in order to achieve and sustain viral suppression. High rates of viral suppression have been observed at more moderate levels of adherence with newer antiretroviral regimens. The term 'forgiveness' is being used to describe the ability of a regimen to achieve and sustain viral suppression, despite suboptimal adherence. A variety of pharmacological, viral and host properties determine the level of forgiveness of any specific regimen. As the choice of treatment options continues to expand, forgiveness of non-adherence is likely to emerge as an increasingly important factor in therapeutic decision-making.

  9. Antioxidant protection from HIV-1 gp120-induced neuroglial toxicity

    Directory of Open Access Journals (Sweden)

    Walsh Kimberley A

    2004-05-01

    Full Text Available Abstract Background The pathogenesis of HIV-1 glycoprotein 120 (gp120 associated neuroglial toxicity remains unresolved, but oxidative injury has been widely implicated as a contributing factor. In previous studies, exposure of primary human central nervous system tissue cultures to gp120 led to a simplification of neuronal dendritic elements as well as astrocytic hypertrophy and hyperplasia; neuropathological features of HIV-1-associated dementia. Gp120 and proinflammatory cytokines upregulate inducible nitric oxide synthase (iNOS, an important source of nitric oxide (NO and nitrosative stress. Because ascorbate scavenges reactive nitrogen and oxygen species, we studied the effect of ascorbate supplementation on iNOS expression as well as the neuronal and glial structural changes associated with gp120 exposure. Methods Human CNS cultures were derived from 16–18 week gestation post-mortem fetal brain. Cultures were incubated with 400 μM ascorbate-2-O-phosphate (Asc-p or vehicle for 18 hours then exposed to 1 nM gp120 for 24 hours. The expression of iNOS and neuronal (MAP2 and astrocytic (GFAP structural proteins was examined by immunohistochemistry and immunofluorescence using confocal scanning laser microscopy (CSLM. Results Following gp120 exposure iNOS was markedly upregulated from undetectable levels at baseline. Double label CSLM studies revealed astrocytes to be the prime source of iNOS with rare neurons expressing iNOS. This upregulation was attenuated by the preincubation with Asc-p, which raised the intracellular concentration of ascorbate. Astrocytic hypertrophy and neuronal injury caused by gp120 were also prevented by preincubation with ascorbate. Conclusions Ascorbate supplementation prevents the deleterious upregulation of iNOS and associated neuronal and astrocytic protein expression and structural changes caused by gp120 in human brain cell cultures.

  10. Differential Persistence of Transmitted HIV-1 Drug Resistance Mutation Classes

    Science.gov (United States)

    Jain, Vivek; Sucupira, Maria C.; Bacchetti, Peter; Hartogensis, Wendy; Diaz, Ricardo S.; Kallas, Esper G.; Janini, Luiz M.; Liegler, Teri; Pilcher, Christopher D.; Grant, Robert M.; Cortes, Rodrigo; Deeks, Steven G.

    2011-01-01

    Background. Transmitted human immunodeficiency virus type 1 (HIV-1) drug resistance (TDR) mutations can become replaced over time by emerging wild-type viral variants with improved fitness. The impact of class-specific mutations on this rate of mutation replacement is uncertain. Methods. We studied participants with acute and/or early HIV infection and TDR in 2 cohorts (San Francisco, California, and São Paulo, Brazil). We followed baseline mutations longitudinally and compared replacement rates between mutation classes with use of a parametric proportional hazards model. Results. Among 75 individuals with 195 TDR mutations, M184V/I became undetectable markedly faster than did nonnucleoside reverse-transcriptase inhibitor (NNRTI) mutations (hazard ratio, 77.5; 95% confidence interval [CI], 14.7–408.2; P < .0001), while protease inhibitor and NNRTI replacement rates were similar. Higher plasma HIV-1 RNA level predicted faster mutation replacement, but this was not statistically significant (hazard ratio, 1.71 log10 copies/mL; 95% CI, .90–3.25 log10 copies/mL; P = .11). We found substantial person-to-person variability in mutation replacement rates not accounted for by viral load or mutation class (P < .0001). Conclusions. The rapid replacement of M184V/I mutations is consistent with known fitness costs. The long-term persistence of NNRTI and protease inhibitor mutations suggests a risk for person-to-person propagation. Host and/or viral factors not accounted for by viral load or mutation class are likely influencing mutation replacement and warrant further study. PMID:21451005

  11. The choreography of HIV-1 proteolytic processing and virion assembly.

    Science.gov (United States)

    Lee, Sook-Kyung; Potempa, Marc; Swanstrom, Ronald

    2012-11-30

    HIV-1 has been the target of intensive research at the molecular and biochemical levels for >25 years. Collectively, this work has led to a detailed understanding of viral replication and the development of 24 approved drugs that have five different targets on various viral proteins and one cellular target (CCR5). Although most drugs target viral enzymatic activities, our detailed knowledge of so much of the viral life cycle is leading us into other types of inhibitors that can block or disrupt protein-protein interactions. Viruses have compact genomes and employ a strategy of using a small number of proteins that can form repeating structures to enclose space (i.e. condensing the viral genome inside of a protein shell), thus minimizing the need for a large protein coding capacity. This creates a relatively small number of critical protein-protein interactions that are essential for viral replication. For HIV-1, the Gag protein has the role of a polyprotein precursor that contains all of the structural proteins of the virion: matrix, capsid, spacer peptide 1, nucleocapsid, spacer peptide 2, and p6 (which contains protein-binding domains that interact with host proteins during budding). Similarly, the Gag-Pro-Pol precursor encodes most of the Gag protein but now includes the viral enzymes: protease, reverse transcriptase (with its associated RNase H activity), and integrase. Gag and Gag-Pro-Pol are the substrates of the viral protease, which is responsible for cleaving these precursors into their mature and fully active forms (see Fig. 1A).

  12. Biomarker evidence of axonal injury in neuroasymptomatic HIV-1 patients.

    Directory of Open Access Journals (Sweden)

    Jan Jessen Krut

    Full Text Available Prevalence of neurocognitive impairment in HIV-1 infected patients is reported to be high. Whether this is a result of active HIV-related neurodegeneration is unclear. We examined axonal injury in HIV-1 patients by measuring the light subunit of neurofilament protein (NFL in CSF with a novel, sensitive method.With a cross-sectional design, CSF concentrations of neurofilament protein light (NFL (marker of neuronal injury, neopterin (intrathecal immunoactivation and CSF/Plasma albumin ratio (blood-brain barrier integrity were analyzed on CSF from 252 HIV-infected patients, subdivided into untreated neuroasymptomatics (n = 200, HIV-associated dementia (HAD (n = 14 and on combinations antiretroviral treatment (cART (n = 85, and healthy controls (n = 204. 46 HIV-infected patients were included in both treated and untreated groups, but sampled at different timepoints. Furthermore, 78 neuroasymptomatic patients were analyzed before and after treatment initiation.While HAD patients had the highest NFL concentrations, elevated CSF NFL was also found in 33% of untreated neuroasymptomatic patients, mainly in those with blood CD4+ cell counts below 250 cells/μL. CSF NFL concentrations in the untreated neuroasymptomatics and treated groups were equivalent to controls 18.5 and 3.9 years older, respectively. Neopterin correlated with NFL levels in untreated groups while the albumin ratio correlated with NFL in both untreated and treated groups.Increased CSF NFL indicates ongoing axonal injury in many neuroasymptomatic patients. Treatment decreases NFL, but treated patients retain higher levels than controls, indicating either continued virus-related injury or an aging-like effect of HIV infection. NFL correlates with neopterin and albumin ratio, suggesting an association between axonal injury, neuroinflammation and blood-brain barrier permeability. NFL appears to be a sensitive biomarker of subclinical and clinical brain injury in HIV and warrants further

  13. Membrane topology analysis of HIV-1 envelope glycoprotein gp41

    Directory of Open Access Journals (Sweden)

    Xiao Dan

    2010-11-01

    Full Text Available Abstract Background The gp41 subunit of the HIV-1 envelope glycoprotein (Env has been widely regarded as a type I transmembrane protein with a single membrane-spanning domain (MSD. An alternative topology model suggested multiple MSDs. The major discrepancy between the two models is that the cytoplasmic Kennedy sequence in the single MSD model is assigned as the extracellular loop accessible to neutralizing antibodies in the other model. We examined the membrane topology of the gp41 subunit in both prokaryotic and mammalian systems. We attached topological markers to the C-termini of serially truncated gp41. In the prokaryotic system, we utilized a green fluorescent protein (GFP that is only active in the cytoplasm. The tag protein (HaloTag and a membrane-impermeable ligand specific to HaloTag was used in the mammalian system. Results In the absence of membrane fusion, both the prokaryotic and mammalian systems (293FT cells supported the single MSD model. In the presence of membrane fusion in mammalian cells (293CD4 cells, the data obtained seem to support the multiple MSD model. However, the region predicted to be a potential MSD is the highly hydrophilic Kennedy sequence and is least likely to become a MSD based on several algorithms. Further analysis revealed the induction of membrane permeability during membrane fusion, allowing the membrane-impermeable ligand and antibodies to cross the membrane. Therefore, we cannot completely rule out the possible artifacts. Addition of membrane fusion inhibitors or alterations of the MSD sequence decreased the induction of membrane permeability. Conclusions It is likely that a single MSD model for HIV-1 gp41 holds true even in the presence of membrane fusion. The degree of the augmentation of membrane permeability we observed was dependent on the membrane fusion and sequence of the MSD.

  14. The structure and function of HIV-1 accessory protein Vif%HIV-1辅助蛋白Vif的结构与功能

    Institute of Scientific and Technical Information of China (English)

    李震宇; 刘新泳

    2008-01-01

    HIV-1 Vif(viral infectivity factor)蛋白是由保守的vif基因编码的碱性蛋白质,是HIV-1病毒的辅助调节蛋白之一.研究表明Vif蛋白具有调节病毒侵入、组装、出芽和成熟等功能.此外,Vif蛋白能够特异性地与体内抗病毒因子APOBEC3G相互作用,增强病毒的感染性.因此,针对HIV-1Vif蛋白进行抑制剂设计已经成为抗HIV药物研究的热点之一.本文对HIV-1Vif蛋白的结构与功能研究的最新进展进行了综述.

  15. Integrated and Total HIV-1 DNA Predict Ex Vivo Viral Outgrowth.

    Directory of Open Access Journals (Sweden)

    Maja Kiselinova

    2016-03-01

    Full Text Available The persistence of a reservoir of latently infected CD4 T cells remains one of the major obstacles to cure HIV. Numerous strategies are being explored to eliminate this reservoir. To translate these efforts into clinical trials, there is a strong need for validated biomarkers that can monitor the reservoir over time in vivo. A comprehensive study was designed to evaluate and compare potential HIV-1 reservoir biomarkers. A cohort of 25 patients, treated with suppressive antiretroviral therapy was sampled at three time points, with median of 2.5 years (IQR: 2.4-2.6 between time point 1 and 2; and median of 31 days (IQR: 28-36 between time point 2 and 3. Patients were median of 6 years (IQR: 3-12 on ART, and plasma viral load (<50 copies/ml was suppressed for median of 4 years (IQR: 2-8. Total HIV-1 DNA, unspliced (us and multiply spliced HIV-1 RNA, and 2LTR circles were quantified by digital PCR in peripheral blood, at 3 time points. At the second time point, a viral outgrowth assay (VOA was performed, and integrated HIV-1 DNA and relative mRNA expression levels of HIV-1 restriction factors were quantified. No significant change was found for long- and short-term dynamics of all HIV-1 markers tested in peripheral blood. Integrated HIV-1 DNA was associated with total HIV-1 DNA (p<0.001, R² = 0.85, us HIV-1 RNA (p = 0.029, R² = 0.40, and VOA (p = 0.041, R2 = 0.44. Replication-competent virus was detected in 80% of patients by the VOA and it correlated with total HIV-1 DNA (p = 0.039, R² = 0.54. The mean quantification difference between Alu-PCR and VOA was 2.88 log10, and 2.23 log10 between total HIV-1 DNA and VOA. The levels of usHIV-1 RNA were inversely correlated with mRNA levels of several HIV-1 restriction factors (TRIM5α, SAMHD1, MX2, SLFN11, pSIP1. Our study reveals important correlations between the viral outgrowth and total and integrated HIV-1 DNA measures, suggesting that the total pool of HIV-1 DNA may predict the size of the