Project description:This study examines the sites of HIV integration in quiescent CD4 T cells and compares them to activated T cells. The expression patterns of the sites hosting integration events were determined using microarray analysis data from quiescent and activated CD4 T cells.
Project description:This study examines the sites of HIV integration in quiescent CD4 T cells and compares them to activated T cells. The expression patterns of the sites hosting integration events were determined using microarray analysis data from quiescent and activated CD4 T cells. Experiment Overall Design: Integration sites were isolated by inverse PCR analysis. Quiescent and stimulated T cells from different donors were assayed in 10 µg of leukocyte total RNA using a high-density oligonucleotide array (U133a; Affymetrix, Santa Clara, Calif) at baseline and after PSD for genome-wide mRNA expression profiles. All assays were performed by the UCLA DNA Microarray Core (Affymetrix) following the manufacturer's standard protocol, with sample quality assured for RNA concentration and purity using a bioanalyzer (Agilent, Palo Alto, Calif) prior to probe synthesis. Following hybridization of fluorescent complementary RNA probes, microarrays were imaged using a scanner (Affymetrix), and low-level gene expression values were derived using GeneChip Operating Software (GCOS) (Affymetrix) and analyzed using dChip software (Harvard School of Public Health). The data submitted here have been normalized using RMAExpress.
Project description:Retroviral integration is mediated by a unique enzymatic process shared by all retroviruses and retrotransposons. During integration, double-stranded linear viral DNA is inserted into the host genome in a process catalyzed by viral-encoded integrase. However, host cell defenses against HIV-1 integration are not clear. This study identifies -catenin-like protein 1 (CTNNBL1) as a potent inhibitor of HIV-1 integration via association with viral IN and its cofactor, lens epithelium-derived growth factor/p75. CTNNBL1 overexpression blocks HIV-1 integration and inhibits viral replication, whereas CTNNBL1 depletion significantly upregulates HIV-1 integration into the genome of various target cells. Further, CTNNBL1 expression is downregulated in CD4+ T cells by activation, and CTNNBL1 depletion also facilitates HIV-1 integration in resting CD4+ T cells. Thus, host cells may employ CTNNBL1 to inhibit HIV-1 integration into the genome. This finding suggests a strategy for the treatment of HIV infections.
Project description:Latent HIV reservoirs are extremely stable which pose a tremendous challenge to eradicate HIV. Here, we show that HIV explores the integrated stress response (ISR) signaling to establish its quiescent infection, refractory to the clearance for its persistence. HA15, a recently characterized specific ISR agonist, activates ATF4/CHOP signaling to not only disrupt HIV latency but also reduce HIV+ cells in the primary CD4+ T cell model of HIV latency without the induction of cell death in the HIV negative primary CD4+ T cells and the impact of viability in resting CD4+ T cells isolated from people living with HIV (PLWH). Mechanistically, the reduction of HIV+ cells by ISR/ATF4 activation is associated with the enhancement of cellular apoptosis. However, this mainly occurs in the HIV translation negative CD4+ T cells. In fact, ISR/ATF4 activation-induced cell death largely occurs in HIV transcription active (HIV gag-pol) CD4+ T cells. This is involved in HIV RNA-induced innate immune IFIT signaling. During the acute SIV infection in the rhesus macaques, the induction of ATF4 is associated with decrease of SIV reservoir in the intestine in vivo. When further tested in the resting CD4+ T cells isolated from PLWH on ART, the induction of ISR/ATF4 signaling by HA15 reduced HIV DNA reservoir. These findings support that inactivation of ISR/ATF4 signaling is associated with the maintenance of the stable and quiescent HIV reservoirs while enforced ISR/ATF4 signaling reduces translation quiescent HIV reservoirs in CD4+ T cells.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:BACKGROUND: Combination antiretroviral therapy (cART) is able to control HIV-1 viral replication, however long-lived latent infection in resting memory CD4+ T-cells persist. The mechanisms for establishment and maintenance of latent infection in resting memory CD4+ T-cells remain unclear. Previously we have shown that HIV-1 infection of resting CD4+ T-cells co-cultured with CD11c+ myeloid dendritic cells (mDC) produced a population of non-proliferating T-cells with latent infection. Here we asked whether different antigen presenting cells (APC), including subpopulations of DC and monocytes, were able to induce post-integration latent infection in resting CD4+ T-cells, and examined potential cell interactions that may be involved using RNA-seq. RESULTS: mDC (CD1c+), SLAN+ DC and CD14+ monocytes were most efficient in stimulating proliferation of CD4+ T-cells during syngeneic culture and in generating post-integration latent infection in non-proliferating CD4+ T-cells following HIV-1 infection of APC-T-cell co-cultures. In comparison, plasmacytoid DC (pDC) and B-cells did not induce latent infection in APC-T-cell co-cultures. We compared the RNA expression profiles of APC subpopulations that could and could not induce latency in non-proliferating CD4+ T-cells. Gene expression analysis, comparing the mDC, SLAN+ DC and CD14+ monocyte subpopulations to pDC identified 53 upregulated genes that encode proteins expressed on the plasma membrane that could signal to CD4+ T-cells via cell-cell interactions (32 genes), immune checkpoints (IC) (5 genes), T-cell activation (9 genes), regulation of apoptosis (5 genes), antigen presentation (1 gene) and through unknown ligands (1 gene). CONCLUSIONS: APC subpopulations from the myeloid lineage, specifically mDC subpopulations and CD14+ monocytes, were able to efficiently induce post-integration HIV-1 latency in non-proliferating CD4+ T-cells in vitro. Inhibition of key pathways involved in mDC-T-cell interactions and HIV-1 latency may provide novel targets to eliminate HIV latency. mRNA profiles of sorted, pure antigen presenting cells including, CD1c+ myleoid dendirtic cells (mDC), SLAN+ mDC, CD14+ monocytes and plasmacytoid DC (pDC), were generated using next generation sequencing in triplicate, using Illumina Illumina Hiseq 2000.