Gene expression patterns in blood leukocytes discriminate patients with acute infections
ABSTRACT: Each infectious agent represents a unique combination of pathogen-associated molecular patterns that interact with specific pattern-recognition receptors expressed on immune cells. Therefore, we surmised that the blood immune cells of individuals with different infections might bear discriminative transcriptional signatures. Gene expression profiles were obtained for 131 peripheral blood samples from pediatric patients with acute infections caused by influenza A virus, Gram-negative (Escherichia coli) or Gram-positive (Staphylococcus aureus and Streptococcus pneumoniae) bacteria. Thirty-five genes were identified that best discriminate patients with influenza A virus infection from patients with either E coli or S pneumoniae infection. These genes classified with 95% accuracy (35 of 37 samples) an independent set of patients with either influenza A, E coli, or S pneumoniae infection. A different signature discriminated patients with E coli versus S aureus infections with 85% accuracy (34 of 40). Furthermore, distinctive gene expression patterns were observed in patients presenting with respiratory infections of different etiologies. Thus, microarray analyses of patient peripheral blood leukocytes might assist in the differential diagnosis of infectious diseases. Keywords: expression analysis Overall design: Entire study included 144 samples. Only 143 are included in this series because the CHP/CEL file was not available for sample PBMC_Healthy_INF295.
Project description:Each infectious agent represents a unique combination of pathogen-associated molecular patterns that interact with specific pattern-recognition receptors expressed on immune cells. Therefore, we surmised that the blood immune cells of individuals with different infections might bear discriminative transcriptional signatures. Gene expression profiles were obtained for 131 peripheral blood samples from pediatric patients with acute infections caused by influenza A virus, Gram-negative (Escherichia coli) or Gram-positive (Staphylococcus aureus and Streptococcus pneumoniae) bacteria. Thirty-five genes were identified that best discriminate patients with influenza A virus infection from patients with either E coli or S pneumoniae infection. These genes classified with 95% accuracy (35 of 37 samples) an independent set of patients with either influenza A, E coli, or S pneumoniae infection. A different signature discriminated patients with E coli versus S aureus infections with 85% accuracy (34 of 40). Furthermore, distinctive gene expression patterns were observed in patients presenting with respiratory infections of different etiologies. Thus, microarray analyses of patient peripheral blood leukocytes might assist in the differential diagnosis of infectious diseases. Experiment Overall Design: Entire study included 144 samples. Only 143 are included in this series because the CHP/CEL file was not available for sample PBMC_Healthy_INF295.
Project description:The balance between protecting tissue integrity and efficient immune response is critical for host survival. Here we investigate the role of extracellular matrix (ECM) proteolysis in achieving this balance in the lung during influenza virus infection using a combined genomic and proteomic approach. We followed the transcriptional dynamics and ECM- related responses in a mouse model of influenza virus infection, integrated with whole tissue imaging and functional assays. Our study identifies MT1-MMP as a prominent host-ECM-remodeling collagenase in influenza virus infection. We show that selective inhibition of MT1-MMP-driven ECM proteolysis protects the tissue from infection-related structural and compositional damage. Inhibition of MT1-MMP did not significantly alter the immune response or cytokine expression, indicating its dominant role in ECM remodeling. We demonstrate that the available treatment for influenza virus (Tamiflu/ Oseltamivir) does not prevent lung ECM damage and is less effective than anti-MT1-MMP treatment in influenza virus and Streptococcus pneumoniae coinfection paradigms. Importantly, combination therapy of Tamiflu with anti-MT1-MMP shows a strong synergistic effect and results in complete recovery in mice. This study highlights the importance of tissue tolerance agents for surviving infectious diseases, and the potential of such host-pathogen therapy combination for respiratory infections. Overall design: Overall 8 samples were included, in duplicates, both infected and non-infected control cells were includeda. Both MT1-MMP positive and MT1-MMP negative were tested were non-infectdd, MT1-MMP negative cells served as controls.
Project description:Miao2010 - Innate and adaptive immune
responses to primary Influenza A Virus infection
This model is described in the article:
Quantifying the early immune
response and adaptive immune response kinetics in mice infected
with influenza A virus.
Miao H, Hollenbaugh JA, Zand MS,
Holden-Wiltse J, Mosmann TR, Perelson AS, Wu H, Topham DJ.
J. Virol. 2010 Jul; 84(13):
Seasonal and pandemic influenza A virus (IAV) continues to
be a public health threat. However, we lack a detailed and
quantitative understanding of the immune response kinetics to
IAV infection and which biological parameters most strongly
influence infection outcomes. To address these issues, we use
modeling approaches combined with experimental data to
quantitatively investigate the innate and adaptive immune
responses to primary IAV infection. Mathematical models were
developed to describe the dynamic interactions between target
(epithelial) cells, influenza virus, cytotoxic T lymphocytes
(CTLs), and virus-specific IgG and IgM. IAV and immune kinetic
parameters were estimated by fitting models to a large data set
obtained from primary H3N2 IAV infection of 340 mice. Prior to
a detectable virus-specific immune response (before day 5), the
estimated half-life of infected epithelial cells is
approximately 1.2 days, and the half-life of free infectious
IAV is approximately 4 h. During the adaptive immune response
(after day 5), the average half-life of infected epithelial
cells is approximately 0.5 days, and the average half-life of
free infectious virus is approximately 1.8 min. During the
adaptive phase, model fitting confirms that CD8(+) CTLs are
crucial for limiting infected cells, while virus-specific IgM
regulates free IAV levels. This may imply that CD4 T cells and
class-switched IgG antibodies are more relevant for generating
IAV-specific memory and preventing future infection via a more
rapid secondary immune response. Also, simulation studies were
performed to understand the relative contributions of
biological parameters to IAV clearance. This study provides a
basis to better understand and predict influenza virus
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Project description:We profiled the expression of circulating microRNAs (miRNAs) in mice exposed to gram-positive and gram-negative bacteria using Illumina small RNA deep sequencing. Recombinant-specific gram-negative pathogen Escherichia coli (Xen14) and gram-positive pathogen Staphylococcus aureus (Xen29) were used to induce bacterial infection in mice at a concentration of 1 × 108 bacteria/100 μL of phosphate buffered saline (PBS). Small RNA libraries generated from the serum of mice after exposure to PBS, Xen14, Xen29, and Xen14+Xen29 via the routes of subcutaneous injection (I), cut wound (C), or under grafted skin (S) were analyzed using an Illumina HiSeq2000 Sequencer. Following exposure to gram-negative bacteria alone, no differentially expressed miRNA was found in the injection, cut, or skin graft models. Exposure to mixed bacteria induced a similar expression pattern of the circulating miRNAs to that induced by gram-positive bacterial infection. Upon gram-positive bacterial infection, 9 miRNAs (mir-193b-3p, mir-133a-1-3p, mir-133a-2-3p, mir-133a-1-5p, mir-133b-3p, mir-434-3p, mir-127-3p, mir-676-3p, mir-215-5p) showed upregulation greater than 4-fold with a p-value < 0.01. Among them, mir-193b-3p, mir-133a-1-3p, and mir-133a-2-3p presented the most common miRNA targets expressed in the mice exposed to gram-positive bacterial infection. Male C57BL/6 mice (age, 10–12 weeks; weight, 30–35 g) were purchased from BioLasco (Yi-Lan, Taiwan). The mice were anesthetized by intraperitoneal injection of an anesthetic cocktail consisting of 0.1 mg/g ketamine and 0.01 mg/g xylazine. The anesthetized mice were restrained in a supine position on a heated pad to maintain body temperature at 37°C. Recombinant-specific gram-negative pathogen Escherichia coli (Xen14) and gram-positive pathogen Staphylococcus aureus (Xen29) purchased from Caliper (Caliper, USA) were used to induce bacterial infection in the mice at a concentration of 1 × 108 bacteria/100 μL of phosphate buffered saline (PBS). To create mixed gram-negative and gram-positive bacterial infection, 1 × 108 Xen14 bacteria and 1 × 108 Xen29 bacteria/100 μL of PBS were used for wound contamination. Three animal models were used to create bacterial infection routes: subcutaneous injection (hereafter referred to as (I)), cut wound (hereafter referred to as (C)), and skin grafting (hereafter referred to as (S)). In the (I) model, E. coli and/or S. aureus suspensions were injected subcutaneously into the backs of the mice using an Fr. 25 needle. In the (C) model, a 1 cm incision wound was created in the midline of the back, smeared with E. coli and/or S. aureus suspension, and the wound was closed directly with a 4-0 nylon suture. In the (S) model, a 1×1 cm rectangular full- thickness skin graft was lifted from the backs of the mice, E. coli and/or S. aureus suspensions were spread over the wound bed, and the skin graft was reattached and closed with a 4-0 nylon suture. An additional group of animals in each of these three models was inoculated with PBS to serve as a negative control. Small RNA libraries generated from the serum of mice after exposure to PBS, Xen14, Xen29, and Xen14+Xen29 via the routes of subcutaneous injection (I), cut wound (C), or under grafted skin (S) were analyzed using an Illumina HiSeq2000 Sequencer.
Project description:Staphylococcus aureus is a Gram-positive bacteria frequently isolated from patients with bloodstream infections. Endothelial cells (ECs) play an important role in host cell defence against bacteria, and recent reports have shown that infection of ECs with S. aureus induces a wide range of cytokines and cell surface receptors involved in activating the innate immune response (). The ability of S. aureus to invade nonphagocytic cells, including ECs, has been documented (), however, the knowledge of ECs role in pathogenesis of S. aureus infection is still limited. <br> In this study, we investigate the gene expression program initiated in human ECs by internalized S. aureus, using microarray analysis. We found 156 genes differentially regulated at least threefold, using arrays representing 14 239 genes. The main part of the upregulated genes code for cytokines, cell adhesion molecules, molecules involved in antigen presentation, cell signaling or cell metabolism. A variety of cytokines and chemokines seem to play an important role in S. aureus infection. Despite an apparent inflammatory response, internalized bacteria survived without inducing EC death.<br>
Project description:To explore the circulating miRNA expression after subcutaneous injection of Gram negative and positive bacteria in the mice The recombinant specific Gram negative pathogens Escherichia coli (xen14) and Gram positive pathogens Staphyllococcus aureus (xen29) were purchased from the Caliper (Caliper, Princeton, NJ, USA). 1×108 Escherichia coli or Staphyllococcus aureus pathogen in 100 μl PBS was injected subcutaneously with Fr. 25 needle into the back of the mice to cause bacterial infection of the mice. An extra group of animals was inoculated with PBS to serve as a negative control. The mice had access to food and water ad libitum both before and after bacteria injection. The mice were killed at the indicated time points (4, 8, and 24 h) after the bacteria injection, and whole blood was drawn.
Project description:Infections of the udder by Escherichia coli very often elicit acute inflammation, while Staphylococcus aureus infections tend to cause mild, subclinical inflammation and persistent infections. The molecular causes undercovering the different disease patterns are poorly understood. We therefore profiled kinetics and extent of global changes in the transcriptome of primary bovine mammary epithelia cells (MEC) subsequent to challenging them with heat inactivated preparations of E. coli or S. aureus pathogens. E. coli swiftly and strongly induced expression of cytokines and bactericidal factors. S. aureus elicited a retarded response and failed to quickly induce expression of bactericidal factors. Both pathogens induced a similar pattern of chemokines for cell recruitment into the udder, but E. coli stimulated their synthesis much faster and stronger. The genes which are exclusively and most strongly up-regulated by E. coli may be clustered into a regulatory network with Tumor necrosis factor alpha (TNF-a) and Interleukin 1 (IL-1) in a central position. In contrast, the expression of these master cytokines is barely regulated by S. aureus. Both pathogens quickly trigger enhanced expression of IL-6. This is still possible after completely abrogating MyD88 dependent TLR-signalling in MEC. The E. coli specific strong induction of TNF-a and IL-1 expression may be causative for the severe inflammatory symptoms of animals suffering from E. coli mastitis while avoidance to quickly induce synthesis of bactericidal factors may support persistent survival of S. aureus within the udder. We suggest that S. aureus subverts MyD88-dependent activation of immune gene expression in MEC. We challenged pbMEC cultures with 1E+07 particles per ml of heat inactivated E. coli strain 1303 for 1, 3, 6, and 24 h and compared their transcriptomes to that of untreated control cells. The experiment included three biological replicas (rep1, rep2, rep3), each from a different cow We challenged pbMEC cultures with 1E+07 particles per ml of heat inactivated S. aureus strain 1027 for 1, 3, 6, and 24 h and compared their transcriptomes to that of untreated control cells. The experiment included three biological replicas (rep1, rep2, rep3), each from a different cow
Project description:Initial transcriptional response of human peripheral monocytes infected with a set of three gram-positive bacterial pathogens (Listeria monocytogenes, Staphylococcus aureus and Streptococcus pneumoniae). Monocytes were isolated from five probands.
Project description:Rationale: Lower respiratory tract infections continue to exact unacceptable worldwide mortality, often because the infecting pathogen cannot be identified. The respiratory epithelia provide protection from pneumonias through organism-specific generation of antimicrobial products, offering potential insight into the identity of infecting pathogens. Objective: This study assesses the capacity of the host gene expression response to infection to predict lower respiratory pathogens without reliance on culture data. Methods: Mice were inhalationally challenged with S. pneumoniae, P. aeruginosa, A. fumigatus or PBS prior to whole genome gene expression microarray analysis of their pulmonary parenchyma. Characteristic gene expression patterns for each condition were identified, allowing the derivation of prediction rules for each pathogen. After confirming the predictive capacity of gene expression data in blinded challenges, a computerized algorithm was devised to predict the infectious conditions of subsequent subjects. Measurements and Main Results: We observed robust, pathogen-specific gene expression patterns as early as 2 h after infection. We were able to develop a predictive model that used a limited number of specifically regulated transcripts to discriminate perfectly among infecting pathogens in the training data. Validation trials using an algorithmic decision tree revealed 94.4% diagnostic accuracy when discerning the presence of bacterial infection. The model subsequently differentiated between bacterial pathogens with 71.4% accuracy and between non-bacterial conditions with 70.0% accuracy, both far exceeding the expected diagnostic yield of standard culture-based bronchoscopy with bronchoalveolar lavage. Conclusions: These data substantiate the specificity of the pulmonary innate immune response and support the feasibility of a gene expression-based clinical tool for pneumonia diagnosis. Keywords: pathogen- and time-dependent host lung gene expression changes in pneumonia Overall design: Mouse lungs were removed 6 h after challenge with P. aeruginosa, S. pneumoniae, A. fumigatus or sham (PBS), RNA was collected from leukoreduced lung homogenates, then cRNA was amplified and hybridized to Illumina Sentrix mouse-6 gene expression arrays v1.1. Gene expression data was analyzed to determine if there were distinct patterns of host trasnscription that corresponded with a specific infection.
Project description:Outcome and resolution of an udder inflammation (mastitis) depends on the type of the invading pathogen. Gram-negative pathogens, such as Escherichia coli mostly trigger strong inflammation and full local activation of the immune defense eventually resulting in pathogen elimination. Staphylococcus aureus and other Gram-positive pathogens elicit only weak immune reactions possibly allowing for pathogen persistence. Little is known about the very early molecular determinants of this pathogen-species specific immune response of the udder. We therefore infected healthy mid-lactating heifers with a high dose of defined E. coli1303 or S. aureus1027 pathogens, sampled udder tissues at 1, 2, and 3 h post infection and globally profiled the transcriptome of samples from the gland cistern. We expectedly found that the E. coli infection elicited a fast and strong immune response. Bioinformatics analyses suggested that pathogen recognizing receptors triggered the activation of the IkB/NF-kB signaling cascade inducing the expression of a wealth of inflammation related genes, but also many immune dampeners. S. aureus infection failed to elicit inflammation and activate IkB/NF-kB signaling. Instead, it triggered immune suppressive mechanisms which were, however not outweighed by strong induction of inflammatory genes. Moreover, it activated the wnt/b-catenin signaling cascade resulting in active suppression of NF-kB signaling and rearrangement of the actin-cytoskeleton through modulating expression of the Rho GTPases. These alterations facilitate invasion of pathogens into host cells. We validated experimentally that pathogenic S. aureus, but not E. coli may invade mammary epithelial cells (MEC). Microscopy revealed an altered structure of the actin-cytoskeleton of primary MEC having internalized live GFP-tagged S. aureus pathogens. Our study reveals for the first time the earliest host responses in the udder differentiating E. coli from S. aureus mastitis. The latter is characterized by eliciting immune suppression rather than inflammation and invasion of S. aureus into the epithelial cells of the host. Overall design: 48 samples from 12 animals were analyzed. Three of four quarters per animal were sequentially inoculated with either 5 x E+06 CFU E. coli (n=6) or 5 x E+06CFU S. aureus (n=6) for 1, 2 and 3 h. One control quarter (front right quarter) remained untreated and was used to measure baseline expression values. Transcripts were defined as differentially expressed during infection if the fold change of the infected quarters relative to the unstimulated control quarter exceeded > 1.5 and the p-value of the univariate t-test paired according the individual animal was < 0.05.