scholarly journals Role of Toll Interleukin-1 Receptor (IL-1R) 8, a Negative Regulator of IL-1R/Toll-Like Receptor Signaling, in Resistance to Acute Pseudomonas aeruginosa Lung Infection

2011 ◽  
Vol 80 (1) ◽  
pp. 100-109 ◽  
Author(s):  
Tania Véliz Rodriguez ◽  
Federica Moalli ◽  
Nadia Polentarutti ◽  
Moira Paroni ◽  
Eduardo Bonavita ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Interleukin 1 ◽  
Bacterial Load ◽  
Lung Infection ◽  
Negative Regulator ◽  
Current Evidence ◽  
Toll Like Receptor ◽  
Content Type ◽  
Deficient Mice

ABSTRACTToll interleukin-1 receptor (IL-1R) 8 (TIR8), also known as single Ig IL-1 receptor (IL-R)-related molecule, or SIGIRR, is a member of the IL-1R-like family, primarily expressed by epithelial cells. Current evidence suggests that TIR8 plays a nonredundant role as a negative regulatorin vivounder different inflammatory conditions that are dependent on IL-R and Toll-like receptor (TLR) activation. In the present study, we examined the role of TIR8 in innate resistance to acute lung infections caused byPseudomonas aeruginosa, a Gram-negative pathogen responsible for life-threatening infections in immunocompromised individuals and cystic fibrosis patients. We show that Tir8 deficiency in mice was associated with increased susceptibility to acuteP. aeruginosainfection, in terms of mortality and bacterial load, and to exacerbated local and systemic production of proinflammatory cytokines (gamma interferon [IFN-γ], tumor necrosis factor alpha [TNF-α], IL-1β, and IL-6) and chemokines (CXCL1, CXCL2, and CCL2). It has been reported that host defense againstP. aeruginosaacute lung infection can be improved by blocking IL-1 since exaggerated IL-1β production may be harmful for the host in this infection. In agreement with these data, IL-1RI deficiency rescues the phenotype observed in Tir8-deficient mice: in Tir8−/−IL-1RI−/−double knockout mice we observed higher survival rates, enhanced bacterial clearance, and reduced levels of local and systemic cytokine and chemokine levels than in Tir8-deficient mice. These results suggest that TIR8 has a nonredundant effect in modulating the inflammation caused byP. aeruginosa, in particular, by negatively regulating IL-1RI signaling, which plays a major role in the pathogenesis of this infectious disease.

scholarly journals Mice Lacking γδ T Cells Exhibit Impaired Clearance of Pseudomonas aeruginosa Lung Infection and Excessive Production of Inflammatory Cytokines

2020 ◽  
Vol 88 (6) ◽  
Author(s):  
Toka Omar ◽  
Pascal Ziltener ◽  
Erin Chamberlain ◽  
Zhenyu Cheng ◽  
Brent Johnston
Keyword(s):  
T Cells ◽  
Immune Cells ◽  
Γδ T Cells ◽  
Lung Infection ◽  
Nkt Cell ◽  
Content Type ◽  
Cell Recruitment ◽  
Deficient Mice ◽  
Necrosis Factor

ABSTRACT Pseudomonas aeruginosa is an opportunistic pathogen that causes chronic and life-threatening infections in immunocompromised patients. A better understanding of the role that innate immunity plays in the control of P. aeruginosa infection is crucial for therapeutic development. Specifically, the role of unconventional immune cells like γδ T cells in the clearance of P. aeruginosa lung infection is not yet well characterized. In this study, the role of γδ T cells was examined in an acute mouse model of P. aeruginosa lung infection. In the absence of γδ T cells, mice displayed impaired bacterial clearance and decreased survival, outcomes which were associated with delayed neutrophil recruitment and impaired recruitment of other immune cells (macrophages, T cells, natural killer cells, and natural killer T [NKT] cells) into the airways. Despite reduced NKT cell recruitment in the airways of mice lacking γδ T cells, NKT cell-deficient mice exhibited wild-type level control of P. aeruginosa infection. Proinflammatory cytokines were also altered in γδ T cell-deficient mice, with increased production of interleukin-1β, interleukin-6, and tumor necrosis factor. γδ T cells did not appear to contribute significantly to the production of interleukin-17A or the chemokines CXCL1 and CXCL2. Importantly, host survival could be improved by inhibiting tumor necrosis factor signaling with the soluble receptor construct etanercept in γδ cell-deficient mice. These findings demonstrate that γδ T cells play a protective role in coordinating the host response to P. aeruginosa lung infection, both in contributing to early immune cell recruitment and by limiting inflammation.

scholarly journals Pseudomonas aeruginosa Oligoribonuclease Contributes to Tolerance to Ciprofloxacin by Regulating Pyocin Biosynthesis

2017 ◽  
Vol 61 (3) ◽  
Author(s):  
Fei Chen ◽  
Gukui Chen ◽  
Yiwei Liu ◽  
Yongxin Jin ◽  
Zhihui Cheng ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Type Iii Secretion ◽  
Transcription Initiation ◽  
Global Gene Expression ◽  
Secretion System ◽  
Negative Regulator ◽  
Content Type ◽  
Bacterial Response ◽  
Hydrolysis Of

ABSTRACTBacterial oligoribonuclease (Orn) is a conserved 3′-to-5′ exonuclease. InPseudomonas aeruginosa, it has been demonstrated that Orn plays a major role in the hydrolysis of pGpG, which is required for cyclic-di-GMP homeostasis. Meanwhile, Orn is involved in the degradation of nanoRNAs, which can alter global gene expression by serving as transcription initiation primers. Previously, we found that Orn is required for the type III secretion system and pathogenesis ofP. aeruginosa, indicating a role of Orn in the bacterial response to environmental stimuli. Here we report that Orn is required for the tolerance ofP. aeruginosato ciprofloxacin. Transcriptome analysis of anornmutant revealed the upregulation of pyocin biosynthesis genes. Mutation of genes involved in pyocin biosynthesis in the background of anornmutant restored bacterial tolerance to ciprofloxacin. We further demonstrate that the upregulation of pyocin biosynthesis genes is due to RecA-mediated autoproteolysis of PrtR, which is the major negative regulator of pyocin biosynthesis genes. In addition, the SOS response genes were upregulated in theornmutant, indicating a DNA damage stress. Therefore, our results revealed a novel role of Orn in bacterial tolerance to ciprofloxacin.

scholarly journals Activation of ASC Inflammasome Driven by Toll-Like Receptor 4 Contributes to Host Immunity against Rickettsial Infection

2020 ◽  
Vol 88 (4) ◽  
Author(s):  
Claire Rumfield ◽  
Ilirjana Hyseni ◽  
Jere W. McBride ◽  
David H. Walker ◽  
Rong Fang
Keyword(s):  
Host Susceptibility ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Content Type ◽  
Ifn Γ ◽  
Human Infections ◽  
Deficient Mice ◽  
Dependent Mechanism

ABSTRACT Rickettsiae are cytosolically replicating, obligately intracellular bacteria causing human infections worldwide with potentially fatal outcomes. We previously showed that Rickettsia australis activates ASC inflammasome in macrophages. In the present study, host susceptibility of ASC inflammasome-deficient mice to R. australis was significantly greater than that of C57BL/6 (B6) controls and was accompanied by increased rickettsial loads in various organs. Impaired host control of R. australis in vivo in ASC−/− mice was associated with dramatically reduced levels of interleukin 1β (IL-1β), IL-18, and gamma interferon (IFN-γ) in sera. The intracellular concentrations of R. australis in bone marrow-derived macrophages (BMMs) of TLR4−/− and ASC−/− mice were significantly greater than those in BMMs of B6 controls, highlighting the important role of inflammasome and these molecules in controlling rickettsiae in macrophages. Compared to B6 BMMs, TLR4−/− BMMs failed to secrete a significant level of IL-1β and had reduced expression levels of pro-IL-1β in response to infection with R. australis, suggesting that rickettsiae activate ASC inflammasome via a Toll-like receptor 4 (TLR4)-dependent mechanism. Further mechanistic studies suggest that the lipopolysaccharide (LPS) purified from R. australis together with ATP stimulation led to cleavage of pro-caspase-1 and pro-IL-1β, resulting in TLR4-dependent secretion of IL-1β. Taken together, these observations indicate that activation of ASC inflammasome, most likely driven by interaction of TLR4 with rickettsial LPS, contributes to host protective immunity against R. australis. These findings provide key insights into defining the interactions of rickettsiae with the host innate immune system.

scholarly journals Essential role of IRAK-4 protein and its kinase activity in Toll-like receptor–mediated immune responses but not in TCR signaling

2007 ◽  
Vol 204 (5) ◽  
pp. 1013-1024 ◽  
Author(s):  
Tatsukata Kawagoe ◽  
Shintaro Sato ◽  
Andreas Jung ◽  
Masahiro Yamamoto ◽  
Kosuke Matsui ◽  
...  
Keyword(s):  
Immune Responses ◽  
Kinase Activity ◽  
Interleukin 1 ◽  
Cell Receptor ◽  
Nuclear Factor Κb ◽  
Toll Like Receptor ◽  
Tcr Signaling ◽  
Mitogen Activated Protein

Interleukin-1 receptor–associated kinase 4 (IRAK-4) was reported to be essential for the Toll-like receptor (TLR)– and T cell receptor (TCR)–mediated signaling leading to the activation of nuclear factor κB (NF-κB). However, the importance of kinase activity of IRAK family members is unclear. In this study, we investigated the functional role of IRAK-4 activity in vivo by generating mice carrying a knockin mutation (KK213AA) that abrogates its kinase activity. IRAK-4KN/KN mice were highly resistant to TLR-induced shock response. The cytokine production in response to TLR ligands was severely impaired in IRAK-4KN/KN as well as IRAK-4−/− macrophages. The IRAK-4 activity was essential for the activation of signaling pathways leading to mitogen-activated protein kinases. TLR-induced IRAK-4/IRAK-1–dependent and –independent pathways were involved in early induction of NF-κB–regulated genes in response to TLR ligands such as tumor necrosis factor α and IκBζ. In contrast to a previous paper (Suzuki, N., S. Suzuki, D.G. Millar, M. Unno, H. Hara, T. Calzascia, S. Yamasaki, T. Yokosuka, N.J. Chen, A.R. Elford, et al. 2006. Science. 311:1927–1932), the TCR signaling was not impaired in IRAK-4−/− and IRAK-4KN/KN mice. Thus, the kinase activity of IRAK-4 is essential for the regulation of TLR-mediated innate immune responses.

scholarly journals Role of interleukin-25 in development of spontaneous arthritis in interleukin-1 receptor antagonist-deficient mice

2017 ◽  
Vol 12 ◽  
pp. 62-65
Author(s):  
Yasuharu Abe ◽  
Aya Nambu ◽  
Sachiko Yamaguchi ◽  
Ayako Takamori ◽  
Hajime Suto ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Interleukin 1 ◽  
Interleukin 1 Receptor Antagonist ◽  
Interleukin 25 ◽  
Deficient Mice

scholarly journals Systems Modeling of the Role of Interleukin-21 in the Maintenance of Effector CD4+ T Cell Responses during Chronic Helicobacter pylori Infection

mBio ◽  
2014 ◽  
Vol 5 (4) ◽  
Author(s):  
Adria Carbo ◽  
Danyvid Olivares-Villagómez ◽  
Raquel Hontecillas ◽  
Josep Bassaganya-Riera ◽  
Rupesh Chaturvedi ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
T Cell ◽  
Wild Type ◽  
Content Type ◽  
Interleukin 21 ◽  
H Pylori ◽  
Deficient Mice

ABSTRACTThe development of gastritis duringHelicobacter pyloriinfection is dependent on an activated adaptive immune response orchestrated by T helper (Th) cells. However, the relative contributions of the Th1 and Th17 subsets to gastritis and control of infection are still under investigation. To investigate the role of interleukin-21 (IL-21) in the gastric mucosa duringH. pyloriinfection, we combined mathematical modeling of CD4+T cell differentiation within vivomechanistic studies. We infected IL-21-deficient and wild-type mice withH. pyloristrain SS1 and assessed colonization, gastric inflammation, cellular infiltration, and cytokine profiles. ChronicallyH. pylori-infected IL-21-deficient mice had higherH. pyloricolonization, significantly less gastritis, and reduced expression of proinflammatory cytokines and chemokines compared to these parameters in infected wild-type littermates. Thesein vivodata were used to calibrate anH. pyloriinfection-dependent, CD4+T cell-specific computational model, which then described the mechanism by which IL-21 activates the production of interferon gamma (IFN-γ) and IL-17 during chronicH. pyloriinfection. The model predicted activated expression of T-bet and RORγt and the phosphorylation of STAT3 and STAT1 and suggested a potential role of IL-21 in the modulation of IL-10. Driven by our modeling-derived predictions, we found reduced levels of CD4+splenocyte-specifictbx21androrcexpression, reduced phosphorylation of STAT1 and STAT3, and an increase in CD4+T cell-specific IL-10 expression inH. pylori-infected IL-21-deficient mice. Our results indicate that IL-21 regulates Th1 and Th17 effector responses during chronicH. pyloriinfection in a STAT1- and STAT3-dependent manner, therefore playing a major role controllingH. pyloriinfection and gastritis.IMPORTANCEHelicobacter pyloriis the dominant member of the gastric microbiota in more than 50% of the world’s population.H. pyloricolonization has been implicated in gastritis and gastric cancer, as infection withH. pyloriis the single most common risk factor for gastric cancer. Current data suggest that, in addition to bacterial virulence factors, the magnitude and types of immune responses influence the outcome of colonization and chronic infection. This study uses a combined computational and experimental approach to investigate how IL-21, a proinflammatory T cell-derived cytokine, maintains the chronic proinflammatory T cell immune response driving chronic gastritis duringH. pyloriinfection. This research will also provide insight into a myriad of other infectious and immune disorders in which IL-21 is increasingly recognized to play a central role. The use of IL-21-related therapies may provide treatment options for individuals chronically colonized withH. pylorias an alternative to aggressive antibiotics.

scholarly journals The Effect of Anakinra in Hospitalized Patients with COVID-19: An Updated Systematic Review and Meta-Analysis

2021 ◽  
Vol 10 (19) ◽  
pp. 4462
Author(s):  
Konstantinos G. Kyriakoulis ◽  
Anastasios Kollias ◽  
Garyphallia Poulakou ◽  
Ioannis G. Kyriakoulis ◽  
Ioannis P. Trontzas ◽  
...  
Keyword(s):  
Systematic Review ◽  
Meta Analysis ◽  
Interleukin 1 ◽  
Severe Pneumonia ◽  
Hospitalized Patients ◽  
Current Evidence ◽  
Adjusted Risk ◽  
Risk Of Death ◽  
The Impact

The role of immunomodulatory agents in the treatment of hospitalized patients with COVID-19 has been of increasing interest. Anakinra, an interleukin-1 inhibitor, has been shown to offer significant clinical benefits in patients with COVID-19 and hyperinflammation. An updated systematic review and meta-analysis regarding the impact of anakinra on the outcomes of hospitalized patients with COVID-19 was conducted. Studies, randomized or non-randomized with adjustment for confounders, reporting on the adjusted risk of death in patients treated with anakinra versus those not treated with anakinra were deemed eligible. A search was performed in PubMed/EMBASE databases, as well as in relevant websites, until 1 August 2021. The meta-analysis of six studies that fulfilled the inclusion criteria (n = 1553 patients with moderate to severe pneumonia, weighted age 64 years, men 66%, treated with anakinra 50%, intubated 3%) showed a pooled hazard ratio for death in patients treated with anakinra at 0.47 (95% confidence intervals 0.34, 0.65). A meta-regression analysis did not reveal any significant associations between the mean age, percentage of males, mean baseline C-reactive protein levels, mean time of administration since symptoms onset among the included studies and the hazard ratios for death. All studies were considered as low risk of bias. The current evidence, although derived mainly from observational studies, supports a beneficial role of anakinra in the treatment of selected patients with COVID-19.

scholarly journals Exacerbated Imiquimod-Induced Psoriasis-Like Skin Inflammation in IRF5-Deficient Mice

2020 ◽  
Vol 21 (10) ◽  
pp. 3681
Author(s):  
Momoko Nakao ◽  
Tomomitsu Miyagaki ◽  
Makoto Sugaya ◽  
Shinichi Sato
Keyword(s):  
Critical Role ◽  
Skin Inflammation ◽  
Interferon Α ◽  
Toll Like Receptor ◽  
Adaptive Immune ◽  
Th17 Cytokines ◽  
Factor Α ◽  
Deficient Mice ◽  
Necrosis Factor

Interferon regulatory factors (IRFs) play diverse roles in the regulation of the innate and adaptive immune responses in various diseases. In psoriasis, IRF2 is known to be involved in pathogenesis, while studies on other IRFs are limited. In this study, we investigated the role of IRF5 in psoriasis using imiquimod-induced psoriasis-like dermatitis. Although IRF5 is known to play a critical role in the induction of proinflammatory cytokines by immune cells, such as dendritic cells (DCs), macrophages, and monocytes, IRF5 deficiency unexpectedly exacerbated psoriasiform skin inflammation. The interferon-α and tumor necrosis factor-α mRNA expression levels were decreased, while levels of Th17 cytokines including IL-17, IL-22, and IL-23 were increased in IRF5-deficient mice. Furthermore, IL-23 expression in DCs from IRF5-deficient mice was upregulated both in steady state and after toll-like receptor 7/8 agonist stimulation. Importantly, the expression of IRF4, which is also important for the IL-23 production in DCs, was augmented in DCs from IRF5-deficient mice. Taken together, our results suggest that IRF5 deficiency induces the upregulation of IRF4 in DCs followed by augmented IL-23 production, resulting in the amplification of Th17 responses and the exacerbation of imiquimod-induced psoriasis-like skin inflammation. The regulation of IRF4 or IRF5 expression may be a novel therapeutic approach to psoriasis.

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