Genome-wide transcriptional analysis of flagellin induced reprogramming in mouse corneal epithelial cells in response to Pseudomonas aeruginosa
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ABSTRACT: We previously showed that pre-exposure of the cornea to TLR5 ligand flagellin induces profound mucosal innate protection against pathogenic microbes by reprogramming gene expression. To date, there was no genome-wide cDNA array to detect full scale of flagellin mediated reprogramming of gene expression in mucosal surface epithelial cells. Taking advantage of readily accessible, easily procurable epithelial cell population, this study is the first report to use genome-wide cDNA microarray approach to document genes associated with flagellin-induced protection against Pseudomonas aeruginosa infection in corneal epithelial cells (CECs). Total RNA obtained from isolated mouse corneal epithelial cells of the control (cells scrapped off from the corneas without infection), Pseudomonas aeruginosa infected (6 h post infection) and flagellin pretreated (24 h), followed by Pseudomonas aeruginosa infection (6 h).
Project description:We previously showed that pre-exposure of the cornea to TLR5 ligand flagellin induces profound mucosal innate protection against pathogenic microbes by reprogramming gene expression. To date, there was no genome-wide cDNA array to detect full scale of flagellin mediated reprogramming of gene expression in mucosal surface epithelial cells. Taking advantage of readily accessible, easily procurable epithelial cell population, this study is the first report to use genome-wide cDNA microarray approach to document genes associated with flagellin-induced protection against Pseudomonas aeruginosa infection in corneal epithelial cells (CECs).
Project description:Activators of innate immunity may have potential to combat a broad range of infectious agents. We report that treatment with bacterial flagellin prevented rotavirus (RV) infection in mice and cured chronically RV-infected mice. Protection was independent of adaptive immunity and interferon (IFN, type I and II) and required flagellin receptors Toll-like receptor 5 (TLR5) and NOD-like receptor C4 (NLRC4). Flagellin-induced activation of TLR5 on dendritic cells elicited production of the cytokine interleukin (IL)-22, which induced a protective gene expression program in intestinal epithelial cells. Flagellin also induced NLRC4-dependent production of IL-18 and immediate elimination of RV-infected cells. Administration of IL-22 and IL-18 to mice fully recapitulated the capacity of flagellin to prevent or eliminate RV infection, and thus holds promise as a broad-spectrum antiviral agent.
Project description:Recombinant protein of Pseudomonas aeruginosa hook protein FlgE was added to cultured human corneal epithelial cell line for 4 hours and the mRNA expression profiling was performed using Agilent 8*60K array and dual labeling.
Project description:The healthy gut microbiota is composed of three different functional subgroups, symbionts, commensals and pathobionts. Additionally, infection with pathogenic bacteria can occur. Microbe Associated Molecular Patterns (MAMPs) are expressed by most members of both, microbiota and pathogens and interact with Pattern Recognition Receptors (PRRs), resulting in activation of the innate immune system. It is still unclear whether the interaction of PRRs with MAMPs of different origin, leads to a differential activation of innate immunity and whether thereby, distinction can be made between symbionts, commensals, pathobionts and pathogens. Here we addressed the question whether the interaction of flagellin with Toll-like receptor 5 (TLR5) might be a possible mechanism of the innate immune system to distinguish between the different microbial subgroups and initiate the respective immune response. To characterize distinct cellular immune responses to symbiont or pathogen derived flagellin we run transcriptomics, phosphoproteomics and proteomics of TLR5 overexpressing cells. Responses to different flagellins were characterized by differential kinetics and regulation of protein phosphorylation as well as variant protein expression patterns. In vivo experiments revealed that commensal derived flagellin mediated an inert TLR5 signal, thus not affecting Dextran-Sodium-Sulfate (DSS) induced intestinal inflammation. In vitro pathogenic derived flagellin induced a strong pro-inflammatory TLR5 response and did not ameliorate intestinal inflammation. In contrast, symbiont derived flagellin revealed an intermediate TLR5 activation and clearly ameliorated DSS induced intestinal inflammation thus shifting the host immune response in favor of mucosal immune balance. Bone marrow chimeric mice proofed that CD11c+TLR5+ intestinal lamina propria cells mediate the anti-inflammatory symbiotic effect of flagellin. We suggest that the quality of flagellin-induced TL signal might determine the balance between homeostasis and intestinal inflammation and may help the innate immune system to distinguish between symbionts, commensals, pathobionts and pathogenic microbes. We used microarrays to analyze differential expression of genes between treatments with flagellins of E. coli Nissle (EcN) and Salmonella Typhimurium SL1344 (ST).
Project description:In our study, we used a mouse model infected with Pseudomonas aeruginosa (PA) to provoke a painful, sight-threatening corneal infection. FACS sorted WT and Gal-8-/- neutrophils of PA infected corneas were processed for next-generation transcriptomic RNA sequencing (RNA-seq).
Project description:Vaccine adjuvants enhance adaptive immunity to co-administered antigens. Whereas the modes of action are multiple, the activation of antigen-presenting cells (APC) like dendritic cells by adjuvants is a prerequisite. Detection of microbial signals by innate sensors like Toll-like receptors (TLR) is a major mechanism of APC activation. Most candidate or licensed vaccines assume that adjuvant activity of TLR agonists depends on direct effect on APCs. This study addressed whether TLR stimulation of non-hematopoietic cells could contribute to the adjuvant effect. Nasal administration of flagellin enhanced T cell- and antibody-mediated immunity to co-administered antigens in a TLR5-dependent but inflammasome-independent manner. We found that lung radioresistant cells were sufficient to promote immunity, thereby suggesting that direct TLR5-mediated APC stimulation is dispensable to adjuvant activity. Consistent with this, radioresistant compartment is essential to stimulate the swift TLR5-dependent transcription. The transcriptional response was restricted to the epithelial compartment and was associated to the production of a narrow set of mediators including the chemokine CCL20, known to promote APC recruitment in mucosal tissues. Besides, flagellin was rapidly degraded in lower airways and was not transported into lung parenchyma or peripheral tissues. This study therefore suggests an unexpected mechanism for how TLR agonists act as adjuvant and how epithelium is instrumental to sense and integrate microbial signals to promote adaptive immunity. In conclusion, the immune-enhancing effect of adjuvants on epithelial cells can be harnessed for improving vaccines. 1 µg of flagellin was instillated intranasally to LPS-unresponsive C3H/HeJ mice. Total lung RNA was extracted 1h later and prepare for hybridization on Affymetrix microarrays.
Project description:Genome-wide transcriptional analysis of flagellin induced reprogramming in mouse corneal epithelial cells in response to Pseudomonas aeruginosa
Project description:Recombinant protein of Pseudomonas aeruginosa hook protein FlgE was added to cultured human corneal epithelial cell line for 4 hours and the mRNA expression profiling was performed using Agilent 8*60K array and dual labeling. Three triplicates were included for FlgE treatment and PBS control respectively, thus producing three pairs of samples for array, namely E1PBS1, E2PBS2, E3PBS3.
Project description:Bronchial epithelial cells represent the first line of defense against invading airborne pathogens. They are important contributors to innate mucosal immunity and provide a variety of anti-microbial effectors. To investigate the role of epithelial cells upon infection of airway pathogens, we stimulated BEAS-2B cells for 4 h with UV-inactivated bronchial pathogens including Staphylococcus aureus, Pseudomonas aeruginosa and Respiratory Syncitial Virus (RSV) that among other receptors can strongly activate TLR2, TLR4 and TLR3, respectively. Keywords: expression profiling, response to pathogens
Project description:Inflammasome activation is critical for host defense against various microbial infections. Activation of the NLRC4 inflammasome requires detection of flagellin or type III secretion system (T3SS) components by NLR family apoptosis inhibitory proteins (NAIPs); yet how this pathway is regulated is unknown. Here we found that interferon regulatory factor 8 (IRF8) is required for optimal activation of the NLRC4 inflammasome in bone marrow-derived macrophages infected with Salmonella Typhimurium, Burkholderia thailandensis, or Pseudomonas aeruginosa but is dispensable for activation of the canonical and non-canonical NLRP3, AIM2, and Pyrin inflammasomes. IRF8 governs the transcription of Naips to allow detection of flagellin or T3SS proteins to mediate NLRC4 inflammasome activation. Furthermore, we found that IRF8 confers protection against bacterial infection in vivo, owing to its role in inflammasome-dependent cytokine production and pyroptosis. Altogether, our findings suggest that IRF8 is a critical regulator of NAIPs and NLRC4 inflammasome activation for defense against bacterial infection.