Article

The CDK Inhibitor p21Cip1/WAF1 Is Induced by Fc R Activation and Restricts the Replication of Human Immunodeficiency Virus Type 1 and Related Primate Lentiviruses in Human Macrophages

Institut Pasteur, Unité de Régulation des Infections Rétrovirales, Paris, France.
Journal of Virology (Impact Factor: 4.65). 09/2009; 83(23):12253-65. DOI: 10.1128/JVI.01395-09
Source: PubMed

ABSTRACT Macrophages are major targets of human immunodeficiency virus type 1 (HIV-1). We have previously shown that aggregation of activating immunoglobulin G Fc receptors (FcgammaR) by immune complexes inhibits reverse transcript accumulation and integration of HIV-1 and related lentiviruses in monocyte-derived macrophages. Here, we show that FcgammaR-mediated restriction of HIV-1 is not due to enhanced degradation of incoming viral proteins or cDNA and is associated to the induction of the cyclin-dependent kinase inhibitor p21(Cip1/WAF1) (p21). Small interfering RNA-mediated p21 knockdown rescued viral replication in FcgammaR-activated macrophages and enhanced HIV-1 infection in unstimulated macrophages by increasing reverse transcript and integrated DNA levels. p21 induction by other stimuli, such as phorbol myristate acetate and the histone deacetylase inhibitor MS-275, was also associated with preintegrative blocks of HIV-1 replication in macrophages. Binding of p21 to reverse transcription/preintegration complex-associated HIV-1 proteins was not detected in yeast two-hybrid, pulldown, or coimmunoprecipitation assays, suggesting that p21 may affect viral replication independently of a specific interaction with an HIV-1 component. Consistently, p21 silencing rescued viral replication from the FcgammaR-mediated restriction also in simian immunodeficiency virus SIV(mac)- and HIV-2-infected macrophages. Our results point to a role of p21 as an inhibitory factor of lentiviral infection in macrophages and to its implication in FcgammaR-mediated restriction.

Download full-text

Full-text

Available from: Anna Bergamaschi, Sep 02, 2015
0 Followers
 · 
104 Views
 · 
27 Downloads
  • Source
    • "In primary macrophages, dendritic cells and resting CD4+ T cells SAMHD1 degrades dNTPs which are required for efficient reverse transcription [2-4]. Two other factors p21 and PAF1 act at an early stage however their mechanism of action is not yet understood [5,6]. Once reverse transcription is complete the pre-integration complex (PIC) containing the double stranded (ds)DNA is then formed and integrated into the genome of the host cell. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The discovery of novel anti-viral restriction factors illuminates unknown aspects of innate sensing and immunity. We identified RNA-associated Early-stage Anti-viral Factor (REAF) using a whole genome siRNA screen for restriction factors to human immunodeficiency virus (HIV) that act in the early phase of viral replication. We observed more than 50 fold rescue of HIV-1 infection, using a focus forming unit (FFU) assay, following knockdown of REAF by specific siRNA. Quantitative PCR was used to show that REAF knockdown results in an increase of early and late reverse transcripts which impacts the level of integration. REAF thus appears to act at an early stage of the viral life cycle during reverse transcription. Conversely when REAF is over-expressed in target cells less infected cells are detectable and fewer reverse transcripts are produced. Human REAF can also inhibit HIV-2 and simian immunodeficiency virus (SIV) infection. REAF associates with viral nucleic acids and may act to prevent reverse transcription. This report firmly places REAF alongside APOBECs and SAMHD1 as a potent inhibitor of HIV replication acting early in the replication cycle, just after cell entry. We propose that REAF is part of an anti-viral surveillance system destroying incoming retroviruses. This novel mechanism could apply to invasion of cells by any intracellular pathogen.
    Retrovirology 01/2014; 11(1):3. DOI:10.1186/1742-4690-11-3 · 4.77 Impact Factor
  • Source
    • "The status of HIV permissiveness in a given cell subset is dependent in part on virus ability to counteract intrinsic cellular defenses mechanisms [7] mediated by several restriction factors including APOBEC3G [8-10], TRIM5α [11,12], Tetherin/CD317 [13] and most recently discovered, SAMHD1 [14,15]. In addition to restriction factors that directly target the virus, p21/CDKN1A, a potent inhibitor of cyclin dependent kinases, was demonstrated to limit HIV replication in macrophages [16] and CD4+ T-cells from HIV elite controllers [17,18], likely by an indirect mechanism. On the other hand, HIV uses the host-cell machinery for its successful replication. "
    [Show abstract] [Hide abstract]
    ABSTRACT: We previously demonstrated that primary Th1Th17 cells are highly permissive to HIV-1, whereas Th1 cells are relatively resistant. Molecular mechanisms underlying these differences remain unknown. Exposure to replication competent and single-round VSV-G pseudotyped HIV strains provide evidence that superior HIV replication in Th1Th17 vs. Th1 cells was regulated by mechanisms located at entry and post-entry levels. Genome-wide transcriptional profiling identified transcripts upregulated (n = 264) and downregulated (n = 235) in Th1Th17 vs. Th1 cells (p-value < 0.05; fold change cut-off 1.3). Gene Set Enrichment Analysis revealed pathways enriched in Th1Th17 (nuclear receptors, trafficking, p38/MAPK, NF-kappaB, p53/Ras, IL-23) vs. Th1 cells (proteasome, interferon alpha/beta). Differentially expressed genes were classified into biological categories using Gene Ontology. Th1Th17 cells expressed typical Th17 markers (IL-17A/F, IL-22, CCL20, RORC, IL-26, IL-23R, CCR6) and transcripts functionally linked to regulating cell trafficking (CEACAM1, MCAM), activation (CD28, CD40LG, TNFSF13B, TNFSF25, PTPN13, MAP3K4, LTB, CTSH), transcription (PPARgamma, RUNX1, ATF5, ARNTL), apoptosis (FASLG), and HIV infection (CXCR6, FURIN). Differential expression of CXCR6, PPARgamma, ARNTL, PTPN13, MAP3K4, CTSH, SERPINB6, PTK2, and ISG20 was validated by RT-PCR, flow cytometry and/or confocal microscopy. The nuclear receptor PPARgamma was preferentially expressed by Th1Th17 cells. PPARgamma RNA interference significantly increased HIV replication at levels post-entry and prior HIV-DNA integration. Finally, the activation of PPARgamma pathway via the agonist Rosiglitazone induced the nuclear translocation of PPARgamma and a robust inhibition of viral replication. Thus, transcriptional profiling in Th1Th17 vs. Th1 cells demonstrated that HIV permissiveness is associated with a superior state of cellular activation and limited antiviral properties and identified PPARgamma as an intrinsic negative regulator of viral replication. Therefore, triggering PPARgamma pathway via non-toxic agonists may contribute to limiting covert HIV replication and disease progression during antiretroviral treatment.
    Retrovirology 12/2013; 10(1):160. DOI:10.1186/1742-4690-10-160 · 4.77 Impact Factor
  • Source
    • "Furthermore , differentiation of cells to an HIV-1-resistant phenotype is associated with a loss of CDK1 expression [89,90]. Interestingly, Cribier et al. demonstrated a decrease in T592 phosphorylation in cells treated with IFN-α, thus implying a link between type 1 IFN signaling and SAMHD1 activation [82] that may involve p21 Waf1/Cip1 , a cell-cycle-regulated inhibitor of HIV-1 replication [91], and CDK1, a cell-cycle-regulated kinase activity that is induced by IFN-α [92] [93]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: SAMHD1 is the most recent addition to a unique group of host restriction factors that limit retroviral replication at distinct stages of the viral life cycle. SAMHD1 is a deoxynucleoside triphosphate triphosphohydrolase that degrades the intracellular pool of deoxynucleoside triphosphates available during early reverse transcription. SAMHD1 activity is blocked by the Vpx accessory function present in HIV-2 and SIVsm. Mutations in SAMHD1 are associated with the autoimmune disorder Aicardi-Goutières syndrome, thus emphasizing its role in regulation of the immune response. SAMHD1 anti-retroviral activity is modulated by post-translational modifications, cell-cycle dependent functions and cytokine-mediated changes. Innate receptors that sense retroviral DNA intermediates are the focus of intense study, and recent studies have established a link between SAMHD1 restriction, innate sensing of DNA and protective immune responses. Cell-cycle dependent regulation of SAMHD1 by phosphorylation and the increasingly broad range of viruses inhibited by SAMHD1 further emphasize the importance of these mechanisms of host restriction. This review highlights current knowledge regarding SAMHD1 regulation and its impact on innate immune signalling and retroviral restriction.
    Journal of Molecular Biology 10/2013; 425(24). DOI:10.1016/j.jmb.2013.10.022 · 4.33 Impact Factor
Show more