Project description:Arabidopsis MPK4 is involved in the control of antagonism between salicylic acid (SA) and ethylene (ET)/jasmonic acid (JA) pathways in the plant innate immune system as a repressor of the SA pathway, but an activator of the ET/JA pathway. Here we and use comparative microarray analysis of ctr1, ctr1/mpk4, mpk4 and wild type to show that MPK4 is required for only a narrow subset of ET regulated genes.
Project description:Exposure to tear fluid can enhance corneal epithelial cells' ability to resist bacterial virulence mechanisms by upregulating epithelial-derived innate defense genes. The aim of this study was to further elucidate the mechanisms by which tear fluid modulates epithelial cell susceptibility to P. aeruginosa internalization and the relationship to known to be upregulated genes with tear fluid exposure. The hypothesis tested was that tear fluid effects on epithelial cells involve the induction of microRNA expression to modify innate defense gene responses to bacterial challenge.
Project description:Exposure to tear fluid can enhance corneal epithelial cells' ability to resist bacterial virulence mechanisms by upregulating epithelial-derived innate defense genes. The aim of this study was to further elucidate the mechanisms by which tear fluid modulates epithelial cell susceptibility to P. aeruginosa internalization and the relationship to known to be upregulated genes with tear fluid exposure. The hypothesis tested was that tear fluid effects on epithelial cells involve the induction of microRNA expression to modify innate defense gene responses to bacterial challenge. Human corneal epithelial cells were incubated in either 40 ul of fresh human tear fluid or high calcium KGM without antibiotics for 16 hours before extraction or before incubation with P. aeruginosa antigens for 3 h then extraction.
Project description:The innate immune system represents the first line of defense against invading organisms. Among several key innate-immune signaling pathways, the cGAS-STING signaling has emerged as a pivotal component of innate immunity for both foreign- and self-DNA detection. Here, we conducted both computional and experimental assays to identify and characterize novel and key innate immune protein-coding genes and long noncoding RNAs
Project description:Proper defense against microbial infection depends on the controlled activation of the immune system. This is particularly important for the innate immune receptors that recognize viral double-stranded RNA (dsRNA) and initiate antiviral immune responses with the potential of triggering systemic inflammation and immunopathology. How the functions of the dsRNA receptors and their downstream effector molecules are coordinately regulated to avoid excessive immune response is poorly understood. We here demonstrate that stress granules (SGs), biomolecular condensates that form in response to various stresses including viral dsRNA, play key roles in regulating dsRNA-triggered immune response. Upon dsRNA stimulation, SGs recruit many innate immune molecules, including RIG-I-like receptors (RLRs), protein kinase R (PKR) and oligoadenylate synthases (OASes), target these molecules and dsRNA for autophagy and limit their functions through sequestration. In the absence of SGs, dsRNA stimulation results in hyperactivation of inflammatory signaling pathways, global translational arrest and bulk RNA degradation, altogether compromising the cellular capacity to restore homeostasis and triggering cell death. In contrast to most dsRNA-induced immune signaling pathways that are hyperactivated in the absence of SGs, a sub-branch of the RLR pathway (IRF3-dependent type I interferon signaling) shows time-dependent changes, where the initial spike in signaling is followed by a significant drop due to increased caspase-dependent negative feedback regulation. This highlights the role of SGs in regulating the delicate balance between the type I interferon pathway and cell death. Altogether, our data suggest that cells utilize SGs as shock absorbers to moderate antiviral innate immune response, thereby allowing cells to guard against its own immune system as well as viruses.
Project description:Salicylic acid (SA) and ethylene (ET) are two important plant hormones that regulate numerous plant growth, development, and stress response processes. Previous studies have suggested functional interplay of SA and ET in defense response, but precisely how these two hormones co-regulate plant growth and development processes remains unclear. The present findings reveal an antagonism between SA and ET in apical hook formation, a process that ensures successful soil emergence of dicotyledonous etiolated seedlings. Exogenous SA inhibited the ET-induced expression of HOOKLESS1 (HLS1) in a manner dependent on ETHYLENE INSENSITIVE3 (EIN3)/EIN3-LIKE1 (EIL1), the core transcription factors in the ET signaling pathway. We found that SA-activated NONEXPRESSER OF PR GENES1 (NPR1) physically interacted with EIN3 and interfered with the direct binding of EIN3 to target gene promoters, including the HLS1 promoter. Transcriptomic analysis further revealed that NPR1 and EIN3/EIL1 coordinately regulated subsets of genes that mediate plant growth and stress responses, suggesting that the interaction between NPR1 and EIN3/EIL1 might be an important mechanism for integrating the SA and ET signaling pathways in multiple physiological processes. Taken together, our findings shed light on the molecular mechanism underlying SA regulation of apical hook formation as well as the antagonism between SA and ET in early seedling establishment and possibly other physiological processes.
Project description:Pseudomonas aeruginosa is an opportunistic pathogen that causes nosocomial pneumonia and infects patients with cystic fibrosis. P. aeruginosa lung infections are difficult to treat due to bacterial resistance to antibiotics, and strains with multi-drug resistance are becoming more prevalent. Here we examined the use of a small host defense peptide, innate defense regulator 1002 (IDR-1002), in an acute P. aeruginosa lung infection in vivo. IDR-1002 significantly reduced the bacterial burden in the bronchoalveolar lavage fluid (BALF) as well as MCP-1 in the BALF and serum, KC in the serum, and IL-6 in the BALF. RNA-Seq was conducted on lungs and whole blood and the effects of P. aeruginosa, IDR-1002, or the combination of P. aeruginosa and IDR-1002 were evaluated. Differential gene expression analysis showed that P. aeruginosa increased multiple inflammatory and innate immune pathways as well as affected hemostasis, matrix metalloproteinases, collagen biosynthesis, and various metabolism pathways in the lungs and/or blood. Infected mice treated with IDR-1002 had significant changes in gene expression compared to untreated infected mice, with fewer differentially expressed genes associated with the inflammatory and innate immune responses to microbial infection, and treatment also affected morphogenesis, certain metabolic pathways, and lymphocyte activation. Overall, these results show that IDR-1002 was effective in treating P. aeruginosa acute lung infections and associated inflammation.
Project description:This study describes the influence of selected synthetic macrocycle on the gene expression in Pseudomonas aeruginosa PAO1. In this work, we propose two distinct functionalities responsible for a dual mechanism of action. We identified a water-soluble pillararene whose inner cavity tightly binds to specific homoserine lactones (HSLs) thereby interfering with interbacterial signalling, leading to effective synchronized suppression of exotoxins and biofilms in P. aeruginosa. An additional concerted mechanism of action is suggested that involves the cationic functional side groups on the pillararene that disrupt both the bacterial outer membrane and biofilms, to increase the penetration and efficacy of intracellular antibiotics.
Project description:Fribourg2014 - Dynamics of viral antagonism and innate immune response (H1N1 influenza A virus - NC/99)
The dynamics of the interplay between the viral antagonism and the innate immune response has been studied using modelling approaches. The responses of human monocyte-derived dendritic cells infected by two influenza A H1N1 strains (the pandemic swine-origin A/California/4/2009 (Cal/09) and the seasonal A/New Caledonia/20/1999 (NC/99)) that have different clinical outcomes have been modelled. From the time course gene expression measurements of a set of selected genes, the dynamic features of viral antagonism and innate immune response are extracted. It is found that the strength and the time scale of action of viral antagonism is significantly different between the two viruses. This model describes the viral infection by seasonal NC/99.
This model is described in the article:
Model of influenza A virus infection: Dynamics of viral antagonism and innate immune response.
Fribourg M, Hartmann B, Schmolke M, Marjanovic N, Albrecht RA, García-Sastre A, Sealfon SC, Jayaprakash C, Hayot F.
J Theor Biol. 2014 Mar 2;351C:47-57.
Abstract:
Viral antagonism of host responses is an essential component of virus pathogenicity. The study of the interplay between immune response and viral antagonism is challenging due to the involvement of many processes acting at multiple time scales. Here we develop an ordinary differential equation model to investigate the early, experimentally measured, responses of human monocyte-derived dendritic cells to infection by two H1N1 influenza A viruses of different clinical outcomes: pandemic A/California/4/2009 and seasonal A/New Caledonia/20/1999. Our results reveal how the strength of virus antagonism, and the time scale over which it acts to thwart the innate immune response, differs significantly between the two viruses, as is made clear by their impact on the temporal behavior of a number of measured genes. The model thus sheds light on the mechanisms that underlie the variability of innate immune responses to different H1N1 viruses.
This model is hosted on BioModels Database and identified
by: MODEL1403310001.
To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource
for published quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to the public
domain worldwide. Please refer to CC0 Public Domain
Dedication for more information.
Project description:Fribourg2014 - Dynamics of viral antagonism and innate immune response (H1N1 influenza A virus - Cal/09)
The dynamics of the interplay between the viral antagonism and the innate immune response has been studied using modelling approaches. The responses of human monocyte-derived dendritic cells infected by two influenza A H1N1 strains (the pandemic swine-origin A/California/4/2009 (Cal/09) and the seasonal A/New Caledonia/20/1999 (NC/99)) that have different clinical outcomes have been modelled. From the time course gene expression measurements of a set of selected genes, the dynamic features of viral antagonism and innate immune response are extracted. It is found that the strength and the time scale of action of viral antagonism is significantly different between the two viruses. This model describes the viral infection by seasonal Cal/09.
This model is described in the article:
Model of influenza A virus infection: Dynamics of viral antagonism and innate immune response.
Fribourg M, Hartmann B, Schmolke M, Marjanovic N, Albrecht RA, García-Sastre A, Sealfon SC, Jayaprakash C, Hayot F.
J Theor Biol. 2014 Mar 2;351C:47-57.
Abstract:
Viral antagonism of host responses is an essential component of virus pathogenicity. The study of the interplay between immune response and viral antagonism is challenging due to the involvement of many processes acting at multiple time scales. Here we develop an ordinary differential equation model to investigate the early, experimentally measured, responses of human monocyte-derived dendritic cells to infection by two H1N1 influenza A viruses of different clinical outcomes: pandemic A/California/4/2009 and seasonal A/New Caledonia/20/1999. Our results reveal how the strength of virus antagonism, and the time scale over which it acts to thwart the innate immune response, differs significantly between the two viruses, as is made clear by their impact on the temporal behavior of a number of measured genes. The model thus sheds light on the mechanisms that underlie the variability of innate immune responses to different H1N1 viruses.
This model is hosted on BioModels Database and identified
by: MODEL1403310002.
To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource
for published quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to the public
domain worldwide. Please refer to CC0 Public Domain
Dedication for more information.