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Circulating Monocytes in HIV-1 infected Viremic Subjects Exhibit an Anti-Apoptotic Gene Signature

ABSTRACT: Mechanisms that may allow circulating monocytes to persist as CD4 T cells diminish in HIV-1 infection have not been investigated. We have characterized steady-state gene expression signatures in circulating monocytes from HIV-infected subjects and have identified a stable anti-apoptosis gene signature comprised of 38 genes associated with p53, CD40L, TNF and MAPKinase signaling networks. The significance of this gene signature is indicated by our demonstration of cadmium chloride- or Fas ligand-induced apoptosis resistance in circulating monocytes in contrast to increasing apoptosis in CD4 T cells from the same infected subjects. As potential mechanisms in vivo, we show that monocyte CCR5 binding by HIV-1 virus or agonist chemokines serve as independent viral and host modulators resulting in increased monocyte apoptosis resistance in vitro. We also show evidence for concordance between circulating monocyte apoptosis-related gene expression in HIV-1 infection in vivo and available datasets following viral infection or envelope exposure in monocyte derived macrophages in vitro. The identification of in vivo gene expression associated with monocyte resistance to apoptosis is of relevance to AIDS pathogenesis since it would contribute to: (1) maintaining viability of infection targets and long-term reservoirs of HIV-1 infection in the monocyte/macrophage populations, and (2) protecting a cell subset critical to host survival in spite of sustained high viral replication. Keywords: two group study design

ORGANISM(S): Homo sapiens

PROVIDER: GSE14542 | GEO | 2009/03/01

SECONDARY ACCESSION(S): PRJNA111631

REPOSITORIES: GEO

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Project description:Chronic immune activation is a hallmark of human immunodeficiency virus (HIV) infection and the best prognostic indicator of disease progression. Suppressing HIV viremia by antiretroviral therapy (ART) restores normal immune response and effectively prolongs life. In HIV-infected individuals who are coinfected with hepatitis C virus (HCV) the immune system is activated despite effective HIV antiretroviral therapy controlling viral load. Here we examined CD14+ monocyte gene expression by high-density microarray analysis and T cell subsets, CD4 and CD8, by flow cytometry to characterize immune activation in monoinfected HCV, monoinfected HIV and HIV/HCV coinfected subjects with undetected HIV viral load. To determine the impact of coinfection on cognition, subjects were evaluated in 7 domains for neuropsychological (NP) performance, which was summarized as global deficit scores (GDS). Gene expression analysis of CD14+ monocytes from coinfected subjects revealed an elevated type 1 interferon (IFN) response profile unique to coinfection. For both CD4 and CD8 T cells, coinfection triggered significantly increased expression of activation markers CD38 and HLA-DR. In the coinfected group, mild cognitive impairment was associated with a type 1 IFN monocyte response but not plasma lipopolysaccharide. These observations raise the possibility that cognitive impairment evident in the HIV/HCV population is associated with the IFN response detected in coinfected individuals. Monocytes isolated from healthy controls (n=17), HCV monoinfected (n=19) and HIV/HCV coinfected (n=17) were analyzed for gene expression using high-density microarrays. Whole blood was collected in Vacutainer CPT tubes (BD Biosciences) and PBMCs were enriched by centrifugation. Typically, three million CD14+ monocytes were isolated from 30 ml of whole blood using an anti-CD14 monoclonal antibody immunomagnetic - ferrous bead conjugate according to the manufacturer’s instructions (Miltenyi Biotech). Monocyte purity exceeded 97% with <1% T or B cell contamination as determined by flow cytometry. Monocyte RNA was isolated using a Qiagen RNeasy Micro Kit with an RNA integrity value exceeding 9. Complementary DNA was synthesized and labeled with biotin (iExpress iAmplify kit, Applied Microarrays) and hybridized to Codelink Whole Human Genome Bioarrays (55K probes, Applied Microarrays). Slides were scanned (Axon GenePix 4000B, Molecular Devices), analyzed (CodeLink Expression Software Kit v4.1) and microarray data were normalized with loess normalization using R and Bioconductor package. Determination of differential gene expression and multiple testing correction / false discovery rate adjustments were performed using GeneSpring GX 7.3 software package (Agilent). Microarray data was analyzed using a variety of custom data analytic techniques for gene expression profile identification as described previously. Correlations were determined by Spearman rank correlation coefficient.

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Circulating Monocytes in HIV-1 infected Viremic Subjects Exhibit an Anti-Apoptotic Gene Signature

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