scholarly journals Thrombospondin-1 Restricts Interleukin-36γ-Mediated Neutrophilic Inflammation during Pseudomonas aeruginosa Pulmonary Infection

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Hernán F. Peñaloza ◽  
Tolani F. Olonisakin ◽  
William G. Bain ◽  
Yanyan Qu ◽  
Rick van der Geest ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Host Defense ◽  
Neutrophil Elastase ◽  
Pulmonary Infection ◽  
Cytokine Production ◽  
Matricellular Protein ◽  
Tissue Destruction ◽  
Content Type ◽  
Neutrophilic Inflammation ◽  
Thrombospondin 1

ABSTRACT Interleukin-36γ (IL-36γ), a member of the IL-1 cytokine superfamily, amplifies lung inflammation and impairs host defense during acute pulmonary Pseudomonas aeruginosa infection. To be fully active, IL-36γ is cleaved at its N-terminal region by proteases such as neutrophil elastase (NE) and cathepsin S (CatS). However, it remains unclear whether limiting extracellular proteolysis restrains the inflammatory cascade triggered by IL-36γ during P. aeruginosa infection. Thrombospondin-1 (TSP-1) is a matricellular protein with inhibitory activity against NE and the pathogen-secreted Pseudomonas elastase LasB—both proteases implicated in amplifying inflammation. We hypothesized that TSP-1 tempers the inflammatory response during lung P. aeruginosa infection by inhibiting the proteolytic environment required for IL-36γ activation. Compared to wild-type (WT) mice, TSP-1-deficient (Thbs1−/−) mice exhibited a hyperinflammatory response in the lungs during P. aeruginosa infection, with increased cytokine production and an unrestrained extracellular proteolytic environment characterized by higher free NE and LasB, but not CatS activity. LasB cleaved IL-36γ proximally to M19 at a cleavage site distinct from those generated by NE and CatS, which cleave IL-36γ proximally to Y16 and S18, respectively. N-terminal truncation experiments in silico predicted that the M19 and the S18 isoforms bind the IL-36R complex almost identically. IL-36γ neutralization ameliorated the hyperinflammatory response and improved lung immunity in Thbs1−/− mice during P. aeruginosa infection. Moreover, administration of cleaved IL-36γ induced cytokine production and neutrophil recruitment and activation that was accentuated in Thbs1−/− mice lungs. Collectively, our data show that TSP-1 regulates lung neutrophilic inflammation and facilitates host defense by restraining the extracellular proteolytic environment required for IL-36γ activation. IMPORTANCE Pseudomonas aeruginosa pulmonary infection can lead to exaggerated neutrophilic inflammation and tissue destruction, yet host factors that regulate the neutrophilic response are not fully known. IL-36γ is a proinflammatory cytokine that dramatically increases in bioactivity following N-terminal processing by proteases. Here, we demonstrate that thrombospondin-1, a host matricellular protein, limits N-terminal processing of IL-36γ by neutrophil elastase and the Pseudomonas aeruginosa-secreted protease LasB. Thrombospondin-1-deficient mice (Thbs1−/−) exhibit a hyperinflammatory response following infection. Whereas IL-36γ neutralization reduces inflammatory cytokine production, limits neutrophil activation, and improves host defense in Thbs1−/− mice, cleaved IL-36γ administration amplifies neutrophilic inflammation in Thbs1−/− mice. Our findings indicate that thrombospondin-1 guards against feed-forward neutrophilic inflammation mediated by IL-36γ in the lung by restraining the extracellular proteolytic environment.

scholarly journals 2,3-Dihydroxybenzoic Acid-Containing Nanofiber Wound Dressings Inhibit Biofilm Formation by Pseudomonas aeruginosa

2014 ◽  
Vol 58 (4) ◽  
pp. 2098-2104 ◽  
Author(s):  
Jayesh J. Ahire ◽  
Leon M. T. Dicks
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Iron Chelator ◽  
Wound Dressings ◽  
Tissue Destruction ◽  
Dihydroxybenzoic Acid ◽  
Chronic Infections ◽  
Content Type ◽  
Cell Numbers ◽  
Time Required

ABSTRACTPseudomonas aeruginosaforms biofilms in wounds, which often leads to chronic infections that are difficult to treat with antibiotics. Free iron enhances biofilm formation, delays wound healing, and may even be responsible for persistent inflammation, increased connective tissue destruction, and lipid peroxidation. Exposure ofP. aeruginosaXen 5 to the iron chelator 2,3-dihydroxybenzoic acid (DHBA), electrospun into a nanofiber blend of poly(d,l-lactide) (PDLLA) and poly(ethylene oxide) (PEO), referred to as DF, for 8 h decreased biofilm formation by approximately 75%. This was shown by a drastic decline in cell numbers, from 7.1 log10CFU/ml to 4.8 log10CFU/ml when biofilms were exposed to DF in the presence of 2.0 mM FeCl36H2O. A similar decline in cell numbers was recorded in the presence of 3.0 mM FeCl36H2O and DF. The cells were more mobile in the presence of DHBA, supporting the observation of less biofilm formation at lower iron concentrations. DHBA at MIC levels (1.5 mg/ml) inhibited the growth of strain Xen 5 for at least 24 h. Our findings indicate that DHBA electrospun into nanofibers inhibits cell growth for at least 4 h, which is equivalent to the time required for all DHBA to diffuse from DF. This is the first indication that DF can be developed into a wound dressing to treat topical infections caused byP. aeruginosa.

scholarly journals Vitamin D Deficiency Does Not Result in a Breach of Host Defense in Murine Models of Pneumonia

2016 ◽  
Vol 84 (11) ◽  
pp. 3097-3104 ◽  
Author(s):  
Julia Niederstrasser ◽  
Christian Herr ◽  
Lisa Wolf ◽  
Claus M. Lehr ◽  
Christoph Beisswenger ◽  
...  
Keyword(s):  
Vitamin D ◽  
Pseudomonas Aeruginosa ◽  
Streptococcus Pneumoniae ◽  
Host Defense ◽  
Murine Models ◽  
Deficient Diet ◽  
Content Type ◽  
Cell Counts ◽  
The Impact ◽  
Increased Susceptibility

Vitamin D (VitD) has a role in the regulation of calcium and phosphate metabolism and in addition impacts the activity of the immune system. VitD deficiency might be linked to increased susceptibility to respiratory tract infection. The aim of the present study was to characterize the impact of VitD deficiency on the susceptibility to bacterial infection in murine models. C57BL/6N mice were fed a diet with or without VitD for 10 weeks. The VitD-deficient or -sufficient mice were infected with Pseudomonas aeruginosa or Streptococcus pneumoniae . The colonization and inflammatory response in the lung were analyzed at defined time points. The serum 25-hydroxy-VitD concentration was significantly lower in mice on the VitD-deficient diet. In infection experiments with Pseudomonas aeruginosa or Streptococcus pneumoniae , no differences could be observed in the numbers of viable bacteria or in differential cell counts in the bronchoalveolar lavage fluids. Measurements of inflammatory cytokines (KC and interleukin-1β [IL-1β]) did not show significant differences between the groups. In conclusion, VitD-deficient animals did not show significantly increased susceptibility to infection or an altered course of infection. The immune systems of humans and mice likely respond differently to VitD. Murine models are likely not appropriate for drawing conclusions on the role of VitD in human pulmonary host defense.

scholarly journals Role of Inflammasome-independent Activation of IL-1β by the Pseudomonas aeruginosa Protease LasB

2020 ◽  
Author(s):  
Josh Sun ◽  
Doris L. LaRock ◽  
Elaine A. Skowronski ◽  
Jacqueline M. Kimmey ◽  
Joshua Olson ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Pulmonary Infection ◽  
Opportunistic Pathogen ◽  
List Type ◽  
Pulmonary Infections ◽  
Independent Manner ◽  
Proteolytic Activation ◽  
Neutrophilic Inflammation ◽  
Metalloprotease Inhibitors ◽  
Conventional Antibiotics

AbstractPulmonary damage by Pseudomonas aeruginosa during cystic fibrosis lung infection and ventilator-associated pneumonia is mediated both by pathogen virulence factors and host inflammation. Impaired immune function due to tissue damage and inflammation, coupled with pathogen multidrug resistance, complicates management of these deep-seated infections. Therefore, preservation of lung function and effective immune clearance may be enhanced by selectively controlling inflammation. Pathological inflammation during P. aeruginosa pneumonia is driven by interleukin-1β (IL-1β). This proinflammatory cytokine is canonically regulated by caspase-family inflammasome proteases, but we report that plasticity in IL-1β proteolytic activation allows for its direct maturation by the pseudomonal protease LasB. LasB promotes IL-1β activation, neutrophilic inflammation, and destruction of lung architecture characteristic of severe P. aeruginosa pulmonary infection. Discovery of this IL-1β regulatory mechanism provides a distinct target for anti-inflammatory therapeutics, such that matrix metalloprotease inhibitors blocking LasB limit inflammation and pathology during P. aeruginosa pulmonary infections.HighlightsIL-1β drives pathology during pulmonary infection by Pseudomonas aeruginosa.The Pseudomonas protease LasB cleaves and activates IL-1β independent of canonical and noncanonical inflammasomesMetalloprotease inhibitors active against LasB limit inflammation and bacterial growthResearch in ContextInflammation is highly damaging during lung infections by the opportunistic pathogen Pseudomonas aeruginosa. Sun et al. demonstrate that the Pseudomonas LasB protease directly activates IL-1β in an inflammasome-independent manner. Inhibition of IL-1β conversion by LasB protects against neutrophilic inflammation and destruction of the lung. Adjunctive therapeutics that limit pathological inflammation induced by infection would be beneficial for the treatment of pulmonary infections when used with conventional antibiotics.

NKT cells play a limited role in the neutrophilic inflammatory responses and host defense to pulmonary infection with Pseudomonas aeruginosa

2006 ◽  
Vol 8 (12-13) ◽  
pp. 2679-2685 ◽  
Author(s):  
Takeshi Kinjo ◽  
Masashi Nakamatsu ◽  
Chikara Nakasone ◽  
Natsuo Yamamoto ◽  
Yuki Kinjo ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Host Defense ◽  
Pulmonary Infection ◽  
Inflammatory Responses ◽  
Nkt Cells ◽  
Limited Role

scholarly journals The Pseudomonas aeruginosa Periplasmic Protease CtpA Can Affect Systems That Impact Its Ability To Mount Both Acute and Chronic Infections

2013 ◽  
Vol 81 (12) ◽  
pp. 4561-4570 ◽  
Author(s):  
Jin Seo ◽  
Andrew J. Darwin
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Sigma Factor ◽  
Cell Envelope ◽  
Virulence Gene ◽  
Normal Function ◽  
Host Cells ◽  
Tissue Destruction ◽  
Chronic Infections ◽  
Content Type ◽  
Virulence Gene Expression

ABSTRACTProteases play important roles in the virulence ofPseudomonas aeruginosa. Some are exported to act on host targets and facilitate tissue destruction and bacterial dissemination. Others work within the bacterial cell to process virulence factors and regulate virulence gene expression. Relatively little is known about the role of one class of bacterial serine proteases known as the carboxyl-terminal processing proteases (CTPs). TheP. aeruginosagenome encodes two CTPs annotated as PA3257/Prc and PA5134/CtpA in strain PAO1. Prc degrades mutant forms of the anti-sigma factor MucA to promote mucoidy in some cystic fibrosis lung isolates. However, nothing is known about the role or importance of CtpA. We have now found that endogenous CtpA is a soluble periplasmic protein and that actpAnull mutant has specific phenotypes consistent with an altered cell envelope. Although actpAnull mutation has no major effect on bacterial growth in the laboratory, CtpA is essential for the normal function of the type 3 secretion system (T3SS), for cytotoxicity toward host cells, and for virulence in a mouse model of acute pneumonia. Conversely, increasing the amount of CtpA above its endogenous level induces an uncharacterized extracytoplasmic function sigma factor regulon, an event that has been reported to attenuateP. aeruginosain a rat model of chronic lung infection. Therefore, a normal level of CtpA activity is critical for T3SS function and acute virulence, whereas too much activity can trigger an apparent stress response that is detrimental to chronic virulence.

scholarly journals Interleukin-23-Mediated Inflammation in Pseudomonas aeruginosa Pulmonary Infection

2011 ◽  
Vol 80 (1) ◽  
pp. 398-409 ◽  
Author(s):  
Patricia J. Dubin ◽  
Ashley Martz ◽  
Jessica R. Eisenstatt ◽  
Michael D. Fox ◽  
Alison Logar ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Pulmonary Infection ◽  
Γδ T Cells ◽  
Immunocompromised Host ◽  
Opportunistic Pathogen ◽  
Innate Immune ◽  
Lung Damage ◽  
Content Type ◽  
Interleukin 23 ◽  
Related Mortality

ABSTRACTPseudomonas aeruginosais an opportunistic pathogen that is capable of causing acute and chronic pulmonary infection in the immunocompromised host. In the case of cystic fibrosis (CF), chronicP. aeruginosainfection causes increased mortality by promoting overly exuberant airway inflammation and cumulative lung damage. Identifying the key regulators of this inflammation may lead to the development of new therapies that improveP. aeruginosa-related mortality. We report here that interleukin-23 (IL-23), the cytokine most clearly tied to IL-17-mediated inflammation, also promotes IL-17-independent inflammation duringP. aeruginosapulmonary infection. During the early innate immune response, prior to IL-17 induction, IL-23 acts synergistically with IL-1β to promote early neutrophil (polymorphonuclear leukocyte [PMN]) recruitment. However, at later time points, IL-23 also promoted IL-17 production by lung γδ T cells, which was greatly augmented in the presence of IL-1β. These studies show that IL-23 controls two independent phases of neutrophil recruitment in response toP. aeruginosainfection: early PMN emigration that is IL-17 independent and later PMN emigration regulated by IL-17.

scholarly journals Defect of CARD9 Leads to Impaired Accumulation of Gamma Interferon-Producing Memory Phenotype T Cells in Lungs and Increased Susceptibility to Pulmonary Infection with Cryptococcus neoformans

2014 ◽  
Vol 82 (4) ◽  
pp. 1606-1615 ◽  
Author(s):  
Hideki Yamamoto ◽  
Yuri Nakamura ◽  
Ko Sato ◽  
Yurie Takahashi ◽  
Toshiki Nomura ◽  
...  
Keyword(s):  
Innate Immunity ◽  
T Cells ◽  
Cryptococcus Neoformans ◽  
Host Defense ◽  
Pulmonary Infection ◽  
Gamma Interferon ◽  
Content Type ◽  
Memory Phenotype ◽  
Ifn Γ

ABSTRACTCaspase recruitment domain-containing protein 9 (CARD9) is an adaptor molecule signal that is critical for NF-κB activation and is triggered through C-type lectin receptors (CLRs), which are pattern recognition receptors that recognize carbohydrate structures. Previous studies have reported thatCryptococcus neoformans, a fungal pathogen that causes meningoencephalitis in AIDS patients, is recognized through some CLRs, such as mannose receptors or DC-SIGN. However, the role of CARD9 in the host defense against cryptococcal infection remains to be elucidated. In the present study, we analyzed the role of CARD9 in the host defense against pulmonary infection withC. neoformans. CARD9 gene-disrupted (knockout [KO]) mice were highly susceptible to this infection, as shown by the reduced fungal clearance in the infected lungs of CARD9 KO mice, compared to that in wild-type (WT) mice. Gamma interferon (IFN-γ) production was strongly reduced in CARD9 KO mice during the innate-immunity phase of infection. Reduced IFN-γ synthesis was due to impaired accumulation of NK and memory phenotype T cells, which are major sources of IFN-γ innate-immunity-phase production; a reduction in the accumulation of these cells was correlated with reduced CCL4, CCL5, CXCL9, and CXCL10 synthesis. However, differentiation of Th17 cells, but not of Th1 cells, was impaired at the adaptive-immunity phase in CARD9 KO mice compared to WT mice, although there was no significant difference in the infection susceptibility between interleukin 17A (IL-17A) KO and WT mice. These results suggest that CARD9 KO mice are susceptible toC. neoformansinfection probably due to the reduced accumulation of IFN-γ-expressing NK and memory phenotype T cells at the early stage of infection.

scholarly journals Potential of Host Defense Peptide Prodrugs as Neutrophil Elastase-Dependent Anti-Infective Agents for Cystic Fibrosis

2013 ◽  
Vol 58 (2) ◽  
pp. 978-985 ◽  
Author(s):  
Éanna Forde ◽  
Hilary Humphreys ◽  
Catherine M. Greene ◽  
Deirdre Fitzgerald-Hughes ◽  
Marc Devocelle
Keyword(s):  
Cystic Fibrosis ◽  
Host Defense ◽  
Bactericidal Activity ◽  
Neutrophil Elastase ◽  
Activity Levels ◽  
Host Defense Peptides ◽  
Content Type ◽  
Host Defense Peptide ◽  
Low Toxicity

ABSTRACTHost defense peptides (HDPs) are short antimicrobial peptides of the innate immune system. Deficiencies in HDPs contribute to enhanced susceptibility to infections, e.g., in cystic fibrosis (CF). Exogenous HDPs can compensate for these deficiencies, but their development as antimicrobials is limited by cytotoxicity. Three HDP prodrugs were designed so their net positive charge is masked by a promoiety containing a substrate for the enzyme neutrophil elastase (NE). This approach can confine activation to sites with high NE levels. Enzyme-labile peptides were synthesized, and their activation was investigated using purified NE. Susceptibilities ofPseudomonas aeruginosato parent and prodrug peptides in the presence and absence of NE-rich CF human bronchoalveolar lavage (BAL) fluid and different NaCl concentrations were compared. The effect of the HDP promoiety on cytotoxicity was determined with cystic fibrosis bronchial epithelial (CFBE41o-) cells. NE in CF BAL fluids activated the HDP prodrugs, restoring bactericidal activity against reference and clinical isolates ofP. aeruginosa. However, activation also required the addition of 300 mM NaCl. Under these conditions, the bactericidal activity levels of the HDP prodrugs differed, with pro-P18 demonstrating the greatest activity (90% to 100% of that of the parent, P18, at 6.25 μg/ml). Cytotoxic effects on CFBE41o- cells were reduced by the addition of the promoiety to HDPs. We demonstrate here for the first time the selective activation of novel HDP prodrugs by a host disease-associated enzyme atin vivoconcentrations of the CF lung. This approach may lead to the development of novel therapeutic agents with low toxicity that are active under the challenging conditions of the CF lung.

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