Project description:Human rhinovirus and influenza virus infections of the upper airway lead to colds and the flu and can trigger exacerbations of lower airway diseases including asthma and chronic obstructive pulmonary disease. Despite modest advances in the diagnosis and treatment of infections by these viruses, novel diagnostic and therapeutic targets are still needed to differentiate between the cold and the flu, since the clinical course of influenza can be severe while that of rhinovirus is usually more mild. In our investigation of influenza and rhinovirus infection of human respiratory epithelial cells, we used a systems approach to identify the temporally changing patterns of host gene expression from these viruses. After infection of human bronchial epithelial cells (BEAS-2B) with rhinovirus, influenza virus or co-infection with both viruses, we studied the time-course of host gene expression changes over three days. From these data, we constructed a transcriptional regulatory network model that revealed shared and unique host responses to these viral infections such that after a lag of 4-8 hours, most cell host responses were similar for both viruses, while divergent host cell responses appeared after 24-48 hours. The similarities and differences in gene expression after epithelial infection of rhinovirus, influenza virus, or both viruses together revealed qualitative and quantitative differences in innate immune activation and regulation. These differences help explain the generally mild outcome of rhinovirus infections compared to influenza infections which can be much more severe. Human bronchial epithelial cells (BEAS-2B) were infected with rhinovirus, influenza virus or both viruses and RNAs were then profiled at 10 time points (2, 4, 6, 8, 12, 24, 26, 48, 60 and 72hrs)
Project description:Rhinovirus infections exacerbate chronic respiratory inflammatory diseases such as asthma and chronic obstructive pulmonary disease (COPD). Airway epithelial cells are the primary site of rhinovirus replication and responsible for initiating the host immune response to infection. Numerous studies have reported that the anti-viral innate immune response in asthma is deficient leading to the conclusion that epithelial innate immunity is a key determinant of disease severity during a rhinovirus induced exacerbation. However, deficient rhinovirus-induced epithelial interferon production in asthma has not always been observed. We hypothesised that disparate in vitro airway epithelial infection models lacking genome-wide, time-course analyses have obscured the role of epithelial innate anti-viral immunity in asthma and COPD. To address this, we developed a low multiplicity of infection (MOI) rhinovirus model of differentiated primary epithelial cells obtained from healthy, asthma and COPD donors. Using genome-wide gene expression following infection, we demonstrated that gene expression patterns are similar across patient groups, but that the kinetics of induction are delayed in cells obtained from asthma and COPD donors. Rhinovirus-induced innate immune responses were defined by interferons (type-I, II and III), interferon response factors (IRF1, IRF3 and IRF7), TLR signalling and NF‐kB and STAT1 activation. Induced gene expression was evident at 24 hours and peaked at 48 hours post‐infection in cells from healthy subjects. In contrast, in cells from donors with asthma or COPD induction was maximal at or beyond 72-96 hours post infection. Thus, we propose that propensity for viral exacerbations of asthma and COPD relate to delayed (rather than deficient) expression of epithelial cell innate anti-viral immune genes which in turns leads to a delayed and ultimately more inflammatory host immune response.
Project description:Maturation and activation of plasmacytoid dendritic cells (pDCs), induced by the interaction of pathogens or trauma-derived danger signals, with pattern-recognition receptors, is a pivotal step in pDC innate and adaptive immune activation. Exposure to metabolites present in the pDC microenvironment may well influence critical signaling pathways in their function, and thereby tune host immune responses against endogenous, bacterial and viral pathogens. In this experiment, we have addressed the impact of hyperlipidemia on human pDCs at baseline and after activation. We show that exposure to pro-atherogenic (oxidized) low density lipoproteins led to pDC lipid accumulation, which in turn ablated Toll-like receptor (TLR) 7 and 9 dependent up-regulation of pDC maturation markers CD40, CD83, CD86 and HLA-DR. Transcriptional profiling and in vitro cell experiments revealed that, oxLDL exposure dampened TLR9 activation induced production of pro-inflammatory cytokines in a NUR77/IRF7 dependent manner and impaired the capacity of pDCs to prime and polarize CD4+ T helper (Th) cells. These results highlight the marked impact of hyperlipidemia on pDC responses to pathogen-derived signals.
Project description:<p>Plasmacytoid dendritic cells (pDC) are a subset of dendritic cells with unique immunophenotypic properties and functions. While their role in antiviral immunity through production of type I interferons is well-established, their contributions to anti-tumor immunity are less clear. While some evidence demonstrates that pDC in the tumor microenvironment (TME) may drive CD4+ T cell to become <a href="https://www.ncbi.nlm.nih.gov/gene/50943">Foxp3</a>+ T regulatory cells, little is understood about the relationship of pDC with cytotoxic CD8+ T cell, the key player in antitumor immune responses.</p> <p>In this study, we perform comprehensive immunophenotyping and functional analysis of pDC from the TME and draining lymph nodes of patients with head and neck squamous cell carcinoma (HNSCC) and identify a novel pDC subset characterized by expression of the TNF receptor superfamily member <a href="https://www.ncbi.nlm.nih.gov/gene/?term=7293">CD134 (OX40)</a>. We show that OX40 expression is expressed on intratumoral pDC in both humans and mice in a tumor-model specific fashion and that this subset of pDC enhances tumor associated-antigen (TAA)-specific CD8+ T cell responses. Through transcriptomic profiling of OX40-expressing pDC from the TME, we further characterize gene signatures unique to this pDC subset that support its role as an important immunostimulatory immune population in the TME.</p>
Project description:Human rhinovirus and influenza virus infections of the upper airway lead to colds and the flu and can trigger exacerbations of lower airway diseases including asthma and chronic obstructive pulmonary disease. Despite modest advances in the diagnosis and treatment of infections by these viruses, novel diagnostic and therapeutic targets are still needed to differentiate between the cold and the flu, since the clinical course of influenza can be severe while that of rhinovirus is usually more mild. In our investigation of influenza and rhinovirus infection of human respiratory epithelial cells, we used a systems approach to identify the temporally changing patterns of host gene expression from these viruses. After infection of human bronchial epithelial cells (BEAS-2B) with rhinovirus, influenza virus or co-infection with both viruses, we studied the time-course of host gene expression changes over three days. From these data, we constructed a transcriptional regulatory network model that revealed shared and unique host responses to these viral infections such that after a lag of 4-8 hours, most cell host responses were similar for both viruses, while divergent host cell responses appeared after 24-48 hours. The similarities and differences in gene expression after epithelial infection of rhinovirus, influenza virus, or both viruses together revealed qualitative and quantitative differences in innate immune activation and regulation. These differences help explain the generally mild outcome of rhinovirus infections compared to influenza infections which can be much more severe.
Project description:We employed the single-cell RNA sequencing (scRNA-seq) technology to study HIV-induced transcriptomic change in innate immune cells in lymphoid organs. We performed scRNA-seq on hCD45+hCD3-hCD19- human leukocytes isolated from spleens of humanized NOD/Rag2-/- /γc-/- (NRG) mice transplanted with human CD34+ hematopoietic stem-progenitor cells (NRG-hu HSC mice). We identified major populations of innate immune cells including plasmacytoid dendritic cells (pDC), myeloid dendritic cells (mDC), macrophage, nature killer (NK) cells and innate lymphoid cells (ILC). HIV-1 infection significantly upregulated genes involved in type-I interferon inflammatory pathways in each of the innate immune subsets. Interestingly, we found that the TNF-related apoptosis-inducing ligand (TRAIL) was upregulated in the innate immune populations including pDC, mDC, macrophage, NK and ILC. In summary, we characterized HIV-induced transcriptomic changes of innate immune cells in the spleen at single-cell levels, identified the TRAIL+ innate immune cells and defined an important role of TRAIL signaling pathway in HIV-1 induced CD4+ T cell depletion in vivo.
Project description:Macrophages are central players in immune response, manifesting divergent phenotypes to control inflammation and innate immunity through release of cytokines and other signaling factors. Recently, the focus on metabolism has been reemphasized as critical signaling and regulatory pathways of human pathophysiology, ranging from cancer to aging, often converge on metabolic responses. Here, we used genome-scale modeling and multi-omics (transcriptomics, proteomics, and metabolomics) analysis to assess metabolic features that are critical for macrophage activation. A genome-scale metabolic network for the RAW 264.7 cell line was constructed to determine metabolic modulators of activation. Metabolites well-known to be associated with immunoactivation (glucose and arginine) and immunosuppression (tryptophan and vitamin D3) were among the most critical effectors. Intracellular metabolic mechanisms were assessed, identifying a suppressive role for de-novo nucleotide synthesis. Finally, underlying metabolic mechanisms of macrophage activation were identified by analyzing multi-omic data obtained from LPS-stimulated RAW cells in the context of our flux-based predictions. This study demonstrates that the role of metabolism in regulating activation may be greater than previously anticipated and elucidates underlying connections between activation and metabolic effectors. This submission corresponds to the metabolomics data from this study.