Fibrocytes differ from macrophages but can be infected with HIV-1
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ABSTRACT: Fibrocytes (fibroblastic leukocytes) are recently identified as unique hematopoietic cells with features of both macrophages and fibroblasts. Fibrocytes are known to contribute to the remodeling or fibrosis of various injured tissues. However, their role in viral infection is not fully understood. Here we show that differentiated fibrocytes are phenotypically distinguishable from macrophages but can be infected with HIV-1. Importantly, fibrocytes exhibited persistently infected cell-like phenotypes, the degree of which was more apparent than macrophages. The infected fibrocytes produced replication-competent HIV-1, but expressed HIV-1 mRNA at low levels and strongly resisted HIV-1-induced cell death, which enabled them to support an extremely long-term HIV-1 production at low but steady levels. More importantly, our results suggested that fibrocytes were susceptible to HIV-1 regardless of their differentiation state, in contrast to the fact that monocytes become susceptible to HIV-1 after the differentiation into macrophages. Our findings indicate that fibrocytes are the previously unreported HIV-1 host cells, and suggest the importance of considering fibrocytes as one of long-lived persistently infected cells for curing HIV-1. To find the surface maker for fibrocyte and to analyze why fibrocyte show low HIV-1 replication we done the microarray analysis between fibrocyte(EA1065_65), macrophage(EA1065_02), fibrocyte infected with HIV-1 at Day12(EA1168_08) and macrophage infected with HIV-1 at Day3(EA1168_02).
Project description:Fibrocytes (fibroblastic leukocytes) are recently identified as unique hematopoietic cells with features of both macrophages and fibroblasts. Fibrocytes are known to contribute to the remodeling or fibrosis of various injured tissues. However, their role in viral infection is not fully understood. Here we show that differentiated fibrocytes are phenotypically distinguishable from macrophages but can be infected with HIV-1. Importantly, fibrocytes exhibited persistently infected cell-like phenotypes, the degree of which was more apparent than macrophages. The infected fibrocytes produced replication-competent HIV-1, but expressed HIV-1 mRNA at low levels and strongly resisted HIV-1-induced cell death, which enabled them to support an extremely long-term HIV-1 production at low but steady levels. More importantly, our results suggested that fibrocytes were susceptible to HIV-1 regardless of their differentiation state, in contrast to the fact that monocytes become susceptible to HIV-1 after the differentiation into macrophages. Our findings indicate that fibrocytes are the previously unreported HIV-1 host cells, and suggest the importance of considering fibrocytes as one of long-lived persistently infected cells for curing HIV-1.
Project description:Persistently infected macrophages serve as a long-term HIV reservoir and barrier to viral eradication, and also contribute to neurological complications in patients despite antiretroviral therapy (ART). To better understand the regulation of HIV in macrophages, we compared HIV infected human monocyte derived macrophages (MDM) to acutely infected primary CD4 T cells and Jurkat cell lines latently infected with HIV (JLAT). HIV genomes in MDM were actively transcribed despite enrichment with heterochromatin-associated H3K9me3 across the complete HIV genome in combination with elevated activation marks of H3K9ac and H3K27ac at the LTR. In contrast, JLAT showed conventional bivalent H3K4me3/H3K27me3 while CD4 showed an intermediate epigenotype. 5‘-methylcytosine (5mC) was enriched across the HIV genome in latently infected JLAT cells, while 5‘-hydroxymethylcytosine (5hmc) was enriched in CD4 and MDM. HIV infection induced multinucleation of MDMs along with DNA damage associate p53 phosphorylation, as well as loss of TET2 and the nuclear redistribution of 5-hydoxymethylation. RNA-seq analysis demonstrated that MDMs have a distinct transcriptional response to HIV persistent infection, including activation of CCL7, LAG3, and interferon signaling. Taken together, our findings suggest that HIV induces a unique macrophage nuclear and transcriptional profile, and viral genomes are maintained in a non-canonical bivalent epigenetic state.
Project description:HIV latency is a major obstacle to curing infection. Current strategies to eradicate HIV aim at increasing transcription of the latent provirus. In the present study we observed that latently infected CD4+ T cells from HIV-infected individuals failed to produce viral particles upon ex vivo exposure to SAHA (vorinostat), despite effective inhibition of histone deacetylases. To identify steps that were not susceptible to the action of SAHA or other latency reverting agents, we used a primary CD4+ T cell model, joint host and viral RNA sequencing, and a viral-encoded reporter. This model served to investigate the characteristics of latently infected cells, the dynamics of HIV latency, and the process of reactivation induced by various stimuli. During latency, we observed persistence of viral transcripts but only limited viral translation. Similarly, the reactivating agents SAHA and disulfiram successfully increased viral transcription, but failed to effectively enhance viral translation, mirroring the ex vivo data. This study highlights the importance of post-transcriptional blocks as one mechanism leading to HIV latency that needs to be relieved in order to purge the viral reservoir.
Project description:Macrophages are typically quiescent cells residing in G0, though tissue macrophages have been shown to proliferate locally in tissues; we previously demonstrated that differentiated monocyte derived macrophages (MDM) can be stimulated to re-enter G1 phase of the cell cycle from G0, without cell division. Entry into G1 correlates with an increase in CDK1 expression which phosphorylates the deoxynucleotide-triphosphate hydrolase SAMHD1 at position 592. SAMHD1 not only regulates cellular dNTP levels, but is also a restriction factor for virus replication of HIV-1 and DNA viruses. Here we show that contact with autologous CD4 T cells leads to antigen-independent macrophage cell cycle progression from G0-G1, accompanied by expression of cell cycle associated proteins, including CDK1, and the activation of the canonical MEK-ERK pathway. Further, macrophage cell cycle progression can be blocked not only by anti-cancer drugs targeting the MEK-ERK axis such as Palcociclib, but also by pre-treatment with EGFR antibody, providing additional evidence for cell surface interactions driving proliferative responses. Cell contact with uninfected CD4 T cells renders macrophages ten-fold more susceptible to transduction with VSV-G pseudotyped HIV-1 particles. These findings have important implications for HIV reservoirs in macrophages and potential targeting of macrophages for gene therapy.
Project description:We previously looked the differences in glyco genes using the CFG microarray in normal macrophages and T cells, in conjunction with our studies on effects of glycosylation on HIV/SIV infectivity. In the review of a submitted manuscript, the question arose on the effect of HIV infection on the gene expression. To address this interesting question, we looked at RNA samples derived from macrophages (derived from the sample donor), either infected or not with HIV (in vitro) at different time points. RNA preparations of infected and un-infected Human macrophage at three different time points (5, 7, and 10 days)were sent to the Microarray Core (E). The RNA was amplified, labeled, and hybridized to the GLYCOv3 microarrays.
Project description:Human immunodeficiency virus 1 (HIV-1) infects blood monocytes that cross the blood-brain barrier to the central nervous system inducing neuronal damage. This damage is prompted by the secretion of viral and neurotoxic factors by HIV-infected macrophages and can result in HIV associated neurocognitive disorders (HAND). One of these neurotoxic factors secreted by HIV-infected macrophages is cathepsin B (CATB), a lysosomal cysteine protease that plays an important role in neurodegeneration. CATB interacts with Serum Amyloid P component (SAPC) contributing to HIV-induced neurotoxicity. However, the neuronal apoptosis pathways triggered by CATB and SAPC remain unknown. We aimed to elucidate these pathways in neurons exposed to HIV-infected macrophage conditioned media (MCM) before and after inhibition of CATB or SAPC using Tandem Mass Tag (TMT) proteomics labeling. Based on significant fold change (FC) ≥ ǀ2ǀ and p-value < 0.05 criteria, a total of 10, 48 and 13 proteins were deregulated after inhibiting CATB, SAPC antibodies and the cathepsin B inhibitor CA-074, respectively. We found that antibodies against CATB and SAPC, as well as the CATB inhibitor CA-074 downregulated apoptosis related proteins. CATB, SAPC or apoptotic related proteins could become potential targets against HIV-induced neuronal degeneration.
Project description: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. 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-1b, 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. HIV-1 induced a primed, proinflammatory state, M1HIV, 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 to immune pathogenesis, and provide important targets for therapeutic approaches. Affymetrix arrays were used to identify genomic macrophage response to HIV during viral spread in culture. Experiment Overall Design: An HIV-1 spreading infection was established in primary human macrophages. RNA was extracted from both viral- and mock-infected macrophages cultures over 7 days and hybridized to Affymetrix HG-U95Av2 GeneChips for analysis.
Project description:Macrophages are important effector cells of the immune system and play an important role in mounting inflammatory responses. Macrophages can be activated by different stimuli in the tissue, either by cytokines produced by T helper cells (M1 or M2 polarization) or by the pathogens they encounter. Macrophages are also important target cells of HIV-1 and are preferentially infected by CCR5-using viruses. In this study, we investigated the ability of HIV-1 to induce changes in gene expression in unpolarized macrophages as well as in M1 or M2 polarized cells. We observed that CCR5-using HIV-1 regulates the expression of genes that are also regulated by IL-4 in macrophages. Genes regulated by HIV-1 infection and IL-4 polarization are involved in dampening pro-inflammatory responses in macrophages, which may facilitate HIV-1 to escape from detection by other immune cells. We also observed that changes in macrophage gene expression triggered by CCR5-using HIV-1 differed from those regulated by a CXCR4-using virus. This indicates that CCR5-using HIV-1 may be able to modulate macrophage gene expression to achieve successful replication. Our results provide insight in the complex interplay between HIV-1 and cells of the immune system. Polarized macrophages were obtained by stimulation of primary human monocytes with IFN-gamma (250 U/ml) in combination with TNF-alpha (12.5 ng/ml) (M1), IL-4 (50 ng/ml) (M2a), IL-10 (50 ng/ml) (M2c) for 5 days. Cells were inoculated for 24 hours with one of two HIV-1 strains (CCR5 or CXCR4 using HIV1) or their non replicating counterparts (heat inactivated virus). Macrophages that were not stimulated wiht cyokines or inoculates with HIV-1 were used as control. A total of 16 treatment conditions were tested in triplicate, for a total of 48 samples analysed.
Project description:HIV-1 infection of monocyte-derived macrophages does not elicit a detectable type I IFN response in vitro, however, previously published data has shown that blocking STAT1 and STAT3 inhibits HIV-1 replication. Here we test to see if low levels of IFN inducible genes are detectable in human monocyte-derived macrophages that have been infected with HIV-1 in vitro.
Project description:Macrophages are heterogeneous immune cells with distinct origins, phenotypes, functions and tissue localization. Their susceptibility to HIV-1 is subject to variations from permissiveness to resistance, owing in part to regulatory microRNAs. Here, we used RNAseq to examine the expression of >400 microRNAs in productively infected and bystander cells of HIV-1-exposed macrophage cultures. Two micro-RNAs up regulated in bystander macrophages, miR-221 and miR-222, were identified as negative regulators of CD4 expression and CD4-mediated HIV-1 entry. Both microRNAs were enhanced by TNF-α, an inhibitor of CD4 expression. MiR-221/miR-222 inhibitors recovered HIV-1 entry in TNF-α-treated macrophages by enhancing CD4 expression, and increased HIV-1 replication and spread in macrophages by countering TNF-α-enhanced miR-221/miR-222 expression in bystander cells. In line with these findings, HIV-1-resistant intestinal myeloid cells express higher levels of miR-221 than peripheral blood monocytes. Thus, miR-221/miR-222 act as effectors of the antiviral host response activated during macrophage infection that restrict HIV-1 entry.