Project description:Here we investigated whether a combination of cell-free infection and cell-to-cell spread confers a selective advantage in the evolution of resistance to an inhibitor relative to cell-to-cell spread alone due to the stronger selection pressure against drug sensitive virus. We propagated HIV infection using coculture of infected with uninfected cells in the face of the reverse transcriptase inhibitor efavirenz (EFV), and compared the effect on drug resistance evolution of including one cycle of cell-free infection. In the presence of a single cell-free infection step, we obtained earlier evolution of resistance to EFV. When we increased selective pressure by adding emtricitabine (FTC as a second drug, infection with the cell-free step evolved multidrug resistance and was able to replicate, while infection without a cell-free step failed to evolve multidrug resistance. In conclusion, our results suggest that, HIV cell-to-cell spread has a decreased capacity to rapidly evolve resistance to inhibitors, which is conferred by cell-free infection.
Project description:The goal of this study was to determine how an HIV quasispecies is maintained in the face of selection. We deep sequenced the HIV provirus from cell populations as well as single cells at different time points from in vitro evolution experiments and found that when a less fit and more fit infect the same cell, they share components (complmentation) and therefore allow the less fit to perpetuate. We reproduced a quasispecies to an HIV reverse transcriptase inhibitor. The drug resistant genotype never completely supplanted the drug sensitive genotype, which stabilized at about 20% of viral sequences. Single-cell sequencing showed that resistant genotype frequency plateaued when cells were co-infected with sensitive and resistant genotypes, suggesting a sharing of viral proteins in co-infected cells (complementation), masking genotypic differences. To test if complementation can confer phenotypic drug resistance, we co-transfected fluorescently labelled molecular clones of sensitive and resistant HIV and observed drug resistance in genotypically sensitive virus from co-transfected cells. Resistant virus preferentially co-infected cells with drug sensitive HIV, explaining initiation of co-infections. Modelling showed that a stable quasispecies could form at the experimental multiplicities of infection. Conclusions: Complementation can lead to a quasispecies in infection environments where multiple infections per cell are common
Project description:We invesitgated cellular pathways required for HIV-1 activation using HIV-1-suppressing agents. Despite effective antiretroviral therapy, HIV-1-nfected cells continue to produce viral antigens and induce chronic immune exhaustion. Using a novel dual reporter system and a high-throughput drug screen, we identified FDA-approved drugs which can suppress HIV-1 reactivation in both cell line models and CD4+ T cells from virally suppressed, HIV-1-infected individuals. We identified 11 cellular pathways required for HIV-1 reactivation as druggable targets. Using differential expression analysis, gene set enrichment analysis and exon-intron landscape analysis, we examined the impact of drug treatment on the cellular environment at a genome-wide level.
Project description:The response of human immunodeficiency virus type 1 (HIV-1) quasispecies to antiretroviral therapy is influenced by the ensemble of mutants that composes the evolving population. Low-abundance subpopulations within HIV-1 quasispecies may determine the viral response to the administered drug combinations. However, routine sequencing assays available to clinical laboratories do not recognize HIV-1 minority variants representing less than 25% of the population. Although several alternative and more sensitive genotyping techniques have been developed, including next-generation sequencing (NGS) methods, they are usually very time consuming, expensive and require highly trained personnel, thus becoming unrealistic approaches in daily clinical practice. Here we describe the development and testing of a HIV-1 genotyping DNA microarray that detects and quantifies, in majority and minority viral subpopulations, relevant mutations and amino acid insertions in 42 codons of the pol gene associated with resistance and multidrug resistance to protease (PR) and reverse transcriptase (RT) inhibitors. A customized bioinformatics protocol has been implemented to analyze the microarray hybridization data by including a new normalization procedure and a stepwise filtering algorithm which resulted in the highly accurate (96.33%) detection of positive/negative signals. This microarray has been tested with 57 subtype B HIV-1 clinical samples extracted from multi-treated patients, showing an overall identification of 95.53% and 89.24% of the queried PR and RT codons, respectively, and enough sensitivity to detect minority subpopulations representing as low as 5-10% of the total quasispecies. Such a genotyping platform represents an efficient diagnostic and prognostic tool useful to personalize antiviral treatments in clinical practice.
Project description:To assess the virological response, genotypic resistance profiles, and antiretroviral plasma concentrations in HIV-2 antiretroviral-treated (antiretroviral therapy, ART) patients in Côte d'Ivoire.A cross-sectional survey was conducted among HIV-2 patients receiving ART. Plasma HIV-2 viral load was performed using the Agence Nationale de Recherche sur le SIDA et les hépatites virales (ANRS) assay. Protease and reverse transcriptase sequencing was performed using in-house methods and antiretroviral plasma concentrations were assessed using ultra performance liquid chromatography combined with tandem mass spectrometry.One hundred and forty-five HIV-2-treated patients were enrolled with a median CD4 cell count of 360 cells/?l (interquartile range, IQR?=?215-528). Median duration of ART was 4 years (IQR?=?2-7) and 74% of patients displayed viral load less than 50?copies/ml. Median plasma HIV-2 RNA among patients with viral load more than 50?copies/ml was 3016?copies/ml (IQR?=?436-5156). Most patients (84%) received a lopinavir/ritonavir-based regimen. HIV-2 resistance mutations to nucleoside reverse transcriptase inhibitors and protease inhibitors were detected in 21 of 25 (84%) and 20 of 29 (69%) samples, respectively. The most prevalent nucleoside reverse transcriptase inhibitor resistance mutations were M184I/V (90%), Q151M (24%), and S215F/Y (24%). The most prevalent protease inhibitor resistance mutations were V47A (60%) and I54M (30%). Median CD4 cell counts were 434 cells/?l (292-573) and 204 cells/?l (122-281) in patients with viral load less than 50?copies/ml and those exhibiting virological failure (P?<?0.0001), respectively. The proportions of patients with adequate antiretroviral plasma concentrations were 81 and 93% in patients displaying virological failure and in those with viral load less than 50?copies/ml, respectively (P?=?0.046), suggesting good treatment adherence.We observed adequate drug plasma concentrations and virological suppression in a high proportion of HIV-2-infected patients. However, in cases of virological failure, the limited HIV-2 therapeutic arsenal and cross-resistance dramatically reduced treatment options.
Project description:<p>The overarching goal of this project is to identify and characterize genetic determinants of HIV 1 susceptibility and resistance in samples of African American (AA) and European American (EA) injection drug users (IDUs) by conducting (1) a case/control genome-wide association (GWA) study of HIV 1 infection (positive/negative); (2) a case-only GWA study of viral load among HIV+ IDUs. The study uses existing samples and data from Urban Health Study (UHS) (PI: Alex Kral), which was the longest-running study of street-recruited IDUs in North America, from 1986-2005. UHS was a serial, cross-sectional sero-epidemiological study. Data were collected every 6 months in communities with a high prevalence of injection drug use in the San Francisco Bay Area. It used targeted sampling in neighborhoods at easily accessible community field sites, such as churches, single room occupancy hotels, and community centers. Eligibility criteria for initial entry to the study were (1) injection drug use in past 30 days; (2) ability to provide informed consent; and (3) age 18 or older. The UHS cohort includes over 9,000 African American and European American IDUs whose serum samples have been stored and data are available on HIV antibody status, HIV risk behaviors, drug abuse and demographics.</p> <p>The current study includes 984 HIV+ cases and 2,243 HIV- controls. Approximately two HIV- controls per case were frequency matched on: (1) self-reported ancestry; (2) sex; (3) age; (4) year of ascertainment; and (5) HIV risk class. This GWAS (DA026141) was funded by the National Institute on Drug Abuse (NIDA; PI: Eric O. Johnson). Funding support for genotyping, which was performed at the Johns Hopkins University Center for Inherited Disease Research (CIDR), was provided by NIDA and the NIH contract "High throughput genotyping for studying the genetic contributions to human disease"(HHSN268200782096C). </p>