Project description:Plant pathogenic bacteria encounter a drastic increase in apoplastic pH during the early stages of plant immunity. The effects of alkalization on pathogen-host interactions have not been comprehensively characterized. Here we used a global transcriptomic approach to assess the impact of environmental alkalization on Pseudomonas syringae pv. tomato DC3000 in vitro. In addition to the Type 3 Secretion System (T3SS), we found expression of genes encoding other virulence factors such as iron uptake, and coronatine biosynthesis to be strongly affected by environmental alkalization. We also found activity of extracytoplasmic function sigma factor, AlgU, was induced at pH 5.5 and suppressed at pH 7.8, which are pH levels that this pathogen would likely experience before and during pattern triggered immunity, respectively. This pH-dependent control requires the presence of periplasmic proteases, AlgW and MucP, that function as part of the environmental sensing system that activates AlgU in specific conditions. This is the first example of pH-dependency of AlgU activity, suggesting a regulatory pathway model where pH affects the proteolysis-dependent activation of AlgU. These results contribute to deeper understanding of the role apoplastic pH has on host-pathogen interactions.
Project description:In lung diseases caused by the major mould pathogen Aspergillus fumigatus the pulmonary epithelium is destroyed by invasive growth of fungal hyphae, a process thought to require fungal proteases. Here we show that the A. fumigatus pH-responsive transcription factor PacC governs expression of secreted proteases during invasive lung infections and is required for epithelial invasion and pathogenicity. In addition, A. fumigatus ΔpacC mutants aberrantly remodel the fungal cell wall during infection. This study defines distinct PacC-mediated mechanisms of host damage during pulmonary aspergillosis. ch1: treatment protocol
Project description:In lung diseases caused by the major mould pathogen Aspergillus fumigatus the pulmonary epithelium is destroyed by invasive growth of fungal hyphae, a process thought to require fungal proteases. Here we show that the A. fumigatus pH-responsive transcription factor PacC governs expression of secreted proteases during invasive lung infections and is required for epithelial invasion and pathogenicity. In addition, A. fumigatus M-NM-^TpacC mutants aberrantly remodel the fungal cell wall during infection. This study defines distinct PacC-mediated mechanisms of host damage during pulmonary aspergillosis. ch1: treatment protocol Temporal transcriptional profiling of ATCC46645 strain and isogenic M-NM-^TpacC Aspergillus fumigatus mutant during murine infection
Project description:The innate immune system acts as the first line of defense against invasion of microbial pathogens. Here, macrophages play a substantial role in recognition, phagocytosis and killing of pathogens and the regulation of the innate immune response. Here, interferons play a crucial role in augmenting the antimicrobial functions of macrophages and their ability to produce mediators of immunoregulation. Pathogen recognition activates many different signaling pathways that interact to produce an innate response commensurate with the microbial challenge. The co-occurrence of signaling by sensors of stress and IFN receptors is a hallmark of innate responses to many viral and bacterial pathogens. Our results show changes in chromatin accessibility upon Anisomycin, a drug that induces stress-activation of MAPK pathways, IFNg stimulation and the combination of both or with p38 inhibitor PH-797804, Anisomycin and IFNg.
Project description:The innate immune system acts as the first line of defense against invasion of microbial pathogens. Here, macrophages play a substantial role in recognition, phagocytosis and killing of pathogens and the regulation of the innate immune response. Here, interferons play a crucial role in augmenting the antimicrobial functions of macrophages and their ability to produce mediators of immunoregulation. Pathogen recognition activates many different signaling pathways that interact to produce an innate response commensurate with the microbial challenge. The co-occurrence of signaling by sensors of stress and IFN receptors is a hallmark of innate responses to many viral and bacterial pathogens. Our results show changes in chromatin accessibility upon Anisomycin, a drug that induces stress-activation of MAPK pathways, IFNb stimulation and the combination of both or with p38 inhibitor PH-797804, Anisomycin and IFNb.
Project description:The innate immune system acts as the first line of defense against invasion of microbial pathogens. Here, macrophages play a substantial role in recognition, phagocytosis and killing of pathogens and the regulation of the innate immune response. Here, interferons play a crucial role in augmenting the antimicrobial functions of macrophages and their ability to produce mediators of immunoregulation. Pathogen recognition activates many different signaling pathways that interact to produce an innate response commensurate with the microbial challenge. The co-occurrence of signaling by sensors of stress and IFN receptors is a hallmark of innate responses to many viral and bacterial pathogens. Our results show c-Jun and CREB binding upon Anisomycin, a drug that induces stress-activation of MAPK pathways, IFNg stimulation and the combination of both or with p38 inhibitor PH-797804 and JNK inhibitor SP600125, Anisomycin and IFNg.
Project description:The functional coupling of calcium-mediated signalling and alkaline tolerance has been demonstrated in multiple fungi. The applied relevance of such interplay extends most notably to fungal pathogens of man where the physiological pH of serum and tissues exerts considerable alkaline stress. Drugs targeting the calcium-dependent phosphatase, calcineurin, are potent antifungal agents but also perturb human calcineurin signalling, it has therefore been postulated that abrogation of fungal alkaline tolerance could offer a valuable therapeutic adjunct. To study the interdependency of pH- and calcium-mediated intracellular signalling in the major human fungal pathogen A. fumigatus, we examined the transcriptional response following exposure to 200 mM calcium chloride or alkaline pH (pH 8.0).
Project description:This experiment is to assess the changes of maize genes expression in response to Fusarium graminearum stains wild-type PH-1 and Δcfem1 mutant. F. graminearum is the major casual fungal pathogen of Gibberella stalk rot on maize.
