Project description:The effect of human immunodeficiency virus (HIV) infection and high-level HIV replication on the function of monocytes was investigated. HIV-positive patients had elevated levels of spontaneous production of some or all of the monocyte proinflammatory cytokines measured (interleukin-1beta [IL-1beta], IL-6, and tumor necrosis factor alpha [TNF-alpha]) compared to uninfected controls. In patients on therapy with high frequencies of monocytes producing proinflammatory cytokines, this frequency was diminished in the context of viremia during an interruption of therapy. Diminished production of proinflammatory cytokines during viremia was restored by culture with autologous CD4(+) T cells or monocytes from an on-therapy time point or lipopolysaccharide (LPS). Microarray analysis demonstrated that diminished monocyte production of proinflammatory cytokines was correlated with elevated type I interferon-stimulated gene transcripts. The addition of exogenous alpha 2A interferon diminished the spontaneous production of IL-1beta, IL-6, and TNF-alpha but did not affect responses to LPS, recapitulating the changes observed for HIV-viremic patients. These results suggest that monocyte function is diminished during high-level HIV viremia and that this effect is mediated by chronic stimulation by type I interferons. This effect on monocytes during viremia may play a role in diminished innate or adaptive immune system functions in HIV-infected patients. In addition, the restoration of these functions may also play a role in some immune reconstitution syndromes observed during initiation of therapy.
Project description:Longitudinal analysis of monocyte gene expressions patterns before and after cessation of HAART: understanding the impact of HIV viremia on the monocyte tranascritome. We used microarrays to detail the global program of gene expression underlying defects in monocytes from HIV infected patients during viremia.. Diminished Production of Monocyte Proinflammatory Cytokines During HIV Viremia is Mediated by Interferon-alpha: The in vivo effect of high-level HIV replication on the function of monocytes was investigated. HIV-positive patients had elevated spontaneous production of monocyte proinflammatory cytokines (IL-1?, IL-6, and TNF-?) compared to uninfected controls. These levels were highest in patients on-therapy and was diminished, in the context of viremia, following an interruption of therapy. Diminished production of proinflammatory cytokines during viremia was restored by culturing with autologous CD4+ T cells or monocytes from an on-therapy time point, or by the addition of lipopolysaccharide (LPS). Microarray analysis demonstrated that diminished monocyte production of proinflammatory cytokines was correlated with elevated levels of type I interferon-stimulated gene transcripts. Addition of exogenous IFN-?2A suppressed the spontaneous production of IL-1?, IL-6, and TNF-? but did not affect responses to LPS, recapitulating the changes observed in HIV viremic patients. These results suggest that high-level HIV viremia inhibits monocyte function through chronic stimulation by IFN-?. This effect of viremia on monocytes may play a role in diminished adaptive immune system functions in HIV-infected patients. Restoration of these functions may contribute to the partial immune reconstitution observed following therapy and may be involved in immune reconstitution and inflammatory syndrome seen in some patients. Keywords: Longitudinal comparison
Project description:Iron deposition is frequently observed in human autoinflammatory diseases, such as in the brain of patients with multiple sclerosis or in the synovial fluid of patients with rheumatoid arthritis1-5. Yet, the functional outcome of excessive iron in inflammatory conditions is largely unknown. Granulocyte macrophage colony-stimulating factor (GM-CSF) is a proinflammatory cytokine promoting myeloid cell maturation and activation6 and is essential for the pathogenesis of many autoimmune diseases, including autoimmune encephalomyelitis7-10. Post-transcriptional regulation of GM-CSF is mediated primarily through its 3’ untranslated region (3’UTR) via interaction with specific RNA-binding proteins11. Here we show that a RNA-binding protein PCBP1 senses intracellular iron and post-transcriptionally promotes GM-CSF production. In a short hairpin (sh) RNA screening, we found that Poly(rC) binding protein 1 (PCBP1) enhanced GM-CSF 3’UTR activity and its endogenous mRNA stability. PCBP1 deficiency in autoreactive T cells resulted in a compromised production of GM-CSF and other proinflammatory cytokines, abolishing their capacity in inducing experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Using Crosslinking and Immunoprecipitation (CLIP)12, we demonstrated that PCBP1 promoted mRNA stability by recognizing CU rich elements in the 3’UTRs of pro-inflammatory cytokines. Furthermore, iron depletion induced rapid caspase-mediated proteolysis of PCBP1 and inhibited the production of GM-CSF and a module of 24 cytokines in primary murine and human T cells. Our study thus demonstrates that PCBP1 is critical for the post-transcriptional regulation of proinflammatory cytokines, and indicates that sensing iron may represent a simple yet effective means to adjust the inflammatory response to tissue homeostatic alterations.
Project description:Iron deposition is frequently observed in human autoinflammatory diseases, such as in the brain of patients with multiple sclerosis or in the synovial fluid of patients with rheumatoid arthritis1-5. Yet, the functional outcome of excessive iron in inflammatory conditions is largely unknown. Granulocyte macrophage colony-stimulating factor (GM-CSF) is a proinflammatory cytokine promoting myeloid cell maturation and activation6 and is essential for the pathogenesis of many autoimmune diseases, including autoimmune encephalomyelitis7-10. Post-transcriptional regulation of GM-CSF is mediated primarily through its 3’ untranslated region (3’UTR) via interaction with specific RNA-binding proteins11. Here we show that a RNA-binding protein PCBP1 senses intracellular iron and post-transcriptionally promotes GM-CSF production. In a short hairpin (sh) RNA screening, we found that Poly(rC) binding protein 1 (PCBP1) enhanced GM-CSF 3’UTR activity and its endogenous mRNA stability. PCBP1 deficiency in autoreactive T cells resulted in a compromised production of GM-CSF and other proinflammatory cytokines, abolishing their capacity in inducing experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Using Crosslinking and Immunoprecipitation (CLIP)12, we demonstrated that PCBP1 promoted mRNA stability by recognizing CU rich elements in the 3’UTRs of pro-inflammatory cytokines. Furthermore, iron depletion induced rapid caspase-mediated proteolysis of PCBP1 and inhibited the production of GM-CSF and a module of 24 cytokines in primary murine and human T cells. Our study thus demonstrates that PCBP1 is critical for the post-transcriptional regulation of proinflammatory cytokines, and indicates that sensing iron may represent a simple yet effective means to adjust the inflammatory response to tissue homeostatic alterations.
Project description:Pattern recognition receptors (PRR) detect microbial products and induce cytokines which shape the immunological response. Interleukin-12 (IL-12), tumor necrosis factor alpha (TNF-α) and IL-1β are proinflammatory cytokines which can be essential for resistance against infection, but if produced at high levels, may contribute to immunopathology. In contrast, IL-10 is an immunosuppressive cytokine which dampens proinflammatory responses, but can also lead to defective pathogen clearance. The regulation of these cytokines is therefore central to the generation of an effective but balanced immune response. Here, we show that macrophages derived from C57BL/6 mice produce low levels of IL-12, TNF-α and IL-1β, but high levels of IL-10 in response to TLR4 and TLR2 ligands LPS and PamCSK4, and Burkholderia pseudomallei a Gram-negative bacterium which activates TLR 2/4. In contrast, macrophages derived from BALB/c mice show a reciprocal pattern of cytokine production. Differential production of IL-10 in B. pseudomallei and LPS stimulated C57BL/6 and BALB/c macrophages was due to a type I IFN dependent, but IL-27 independent mechanism. Further, type I IFN contributed to differential IL-1β and IL-12 production in B. pseudomallei and LPS stimulated C57BL/6 and BALB/c macrophages, via both IL-10-dependent and independent mechanisms. These findings highlight key pathways responsible for the regulation of pro- and anti-inflammatory cytokines in macrophages and reveal how they may differ according to the genetic background of the host. Total RNA obtained from bone-marrow derived macrophages of C57BL/6 WT, C57BL/6 Ifnar1-/- and BALB/c mice stimulated with heat-killed Burkholderia pseudomallei or media as controls.
Project description:COVID-19 has claimed millions of lives since the emergence of SARS-CoV-2, and lung disease appears the primary cause of the deaths in COVID-19 patients. However, the underlying mechanisms of COVID-19 pathogenesis remain elusive and there is no existing model where the disease can be faithfully recapitulated and conditions for the infection process can be experimentally controlled. Herein we report the establishment of an ex vivo human precision-cut lung slice (hPCLS) platform for studying SARS-CoV-2 pathogenicity and innate immune response, and for evaluating the efficacy of antiviral drugs against SARS-CoV-2. We show that while SARS-CoV-2 continued to replicate during the course of infection, infectious virus production peaked within 2 days, and rapidly declined thereafter. Although most proinflammatory cytokines examined were induced by SARS-CoV-2 infection, the degree of induction and types of cytokines varied significantly among hPCLS from individual donors, which might reflect the heterogeneity of human populations. In particular, two cytokines (IL-8 and IP-10) are highly and consistently induced, suggesting a role in the pathogenesis of COVID-19. Histopathological examination reveals focal cytopathic effects late in the infection, which are largely limited to type II alveolar cells. Transcriptomic and proteomic analyses identified molecular signatures and cellular pathways that are largely consistent with the progression of COVID-19 in patients. Furthermore, we show that homoherringtonine, a natural plant alkaloid derived from Cephalotoxus fortunei, not only inhibited virus replication but also inflammatory cytokines, and ameliorated the histopathological changes of the lungs caused by SARS-CoV-2, demonstrating the usefulness of the hPCLS platform for evaluating antiviral drugs.
Project description:Cystic fibrosis (CF) is a genetic disorder affecting approximately 1 in 2,500 people in the UK. Here, we generated a number of high-throughput sequence data sets for monocytes and neutrophils from CF patients and matched healthy volunteers (HV); including ChIP-Seq (H3K27Ac), chromatin accessibility (ATAC-Seq), and transcript/gene expression (RNA-Seq) data. Analysis of gene expression and epigenetic profiles demonstrates a robust innate immune gene expression profile that distinguishes CF and HV during periods of disease exacerbation. Upregulation of pathways responsible for the production of proinflammatory cytokines is described.
Project description:The COVID-19 pandemic is spreading globally with high disparity in the susceptibility of the disease severity. Identification of the key underlying factors for this disparity is highly warranted. Here we describe constructing a proteomic risk score based on 20 blood proteomic biomarkers which predict the progression to severe COVID-19. We demonstrate that in our own cohort without infection, this proteomic risk score is positively associated with proinflammatory cytokines mainly among older, but not younger, individuals. We further discovered that a core set of gut microbiota could accurately predict the above proteomic biomarkers using a machine learning model, and that these gut microbiota features are highly correlated with proinflammatory cytokines.