Beta-2-agonist treatment as a potential therapy for acute inhalational lung injury.
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Administration, Inhalation↗
Biomedical subjects
Jeanine P Wiener-Kronish
Publications and source records attributed to Jeanine P Wiener-Kronish.
Passive anti-PcrV treatment protects burned mice against Pseudomonas aeruginosa challenge.
The type III secretion system consists of secreted exoproducts and structural components, such as PcrV, and this system plays an important role in the virulence of Pseudomonas aeruginosa in burned hosts. The purpose of this study was to determine if passive anti-PcrV treatment would protect burned mice from fatal P. aeruginosa challenge, and to determine the type III exoproduct phenotype of the P. aeruginosa used as challenge strains. Antiserum was raised in rabbits. Mice were given a third degree burn, challenged with a lethal dose of P. aeruginosa, and treated with either anti-PcrV or control immunoglobulin intraperitoneally. Protection against three different pseudomonads was tested. Genotyping by PCR and phenotyping by immunoblots showed the P. aeruginosa strains to all be of the invasive type III phenotype: ExoS+ and/or ExoT+, ExoU-, ExoY+. Against all strains, the anti-PcrV treatment yielded significantly better survival (p<0.05) than the control immunoglobulin treatment. Duration of significant protection was improved by giving a second injection of PcrV antisera at 24h postburn. Hence, passive anti-PcrV immunization could protect burned mice against fatal challenge with P. aeruginosa of an invasive type III phenotype. This immunotherapy might be explored further as possible treatment for highly antibiotic resistant P. aeruginosa infections in burned hosts.
Animals↗
Lysophospholipase A activity of Pseudomonas aeruginosa type III secretory toxin ExoU.
Acute lung injury in Pseudomonas aeruginosa pneumonia depends primarily on ExoU that is delivered directly into the eukaryotic cell via the type III secretion system. Recent studies demonstrated that ExoU has lipase activity, and that the cytotoxicity of ExoU is dependent on its patatin-like phospholipase domain. We investigated the phospholipase A (PLA) activity of ExoU. ExoU, but not non-catalytic ExoU-S142A, preincubated with the BEAS-2B cell lysate showed a weak increase of Ca(2+)-independent PLA(2) activity. When activated ExoU was mixed with secretory type PLA(2), more phospholipase activity was observed, suggesting that ExoU has lysophospholipase A (lysoPLA) activity. A significant increase in lysoPLA activity was also observed. Glycerol enhanced this activity and inhibitors of iPLA(2) suppressed ExoU's lysoPLA activity. Our results suggest that ExoU has a potent lysoPLA activity that requires the presence of the catalytically active site Ser(142) with an unknown eukaryotic cell factor(s) for its activation.
Adenosine Triphosphate↗
TLR4 signaling is essential for survival in acute lung injury induced by virulent Pseudomonas aeruginosa secreting type III secretory toxins.
BACKGROUND: The relative contributions of the cytotoxic phenotype of P. aeruginosa expressing type III secretory toxins and an immunocompromised condition lacking normal Toll-like receptor 4 (TLR4) signaling in the pathogenesis of acute lung injury and sepsis were evaluated in a mouse model for Pseudomonas aeruginosa pneumonia. By using lipopolysaccharide-resistant C3H/HeJ mice missing normal TLR4 signaling due to a mutation on the tlr4 gene, we evaluated how TLR4 signaling modulates the pneumonia caused by cytotoxic P. aeruginosa expressing type III secretory toxins. METHODS: We infected C3H/HeJ or C3H/FeJ mice with three different doses of either a cytotoxic P. aeruginosa strain (wild type PA103) or its non-cytotoxic isogenic mutant missing the type III secretory toxins (PA103DeltaUT). Survival of the infected mice was evaluated, and the severity of acute lung injury quantified by measuring alveolar epithelial permeability as an index of acute epithelial injury and the water to dry weight ratios of lung homogenates as an index of lung edema. Bacteriological analysis and cytokine assays were performed in the infected mice. RESULTS: Development of acute lung injury and sepsis was observed in all mouse strains when the cytotoxic P. aeruginosa strain but not the non-cytotoxic strain was instilled in the airspaces of the mice. Only C3H/HeJ mice had severe bacteremia and high mortality when a low dose of the cytotoxic P. aeruginosa strain was instilled in their lungs. CONCLUSION: The cytotoxic phenotype of P. aeruginosa is the critical factor causing acute lung injury and sepsis in infected hosts. When the P. aeruginosa is a cytotoxic strain, the TLR4 signaling system is essential to clear the bacteria to prevent lethal lung injury and bacteremia.
Acute Disease↗
A therapeutic strategy against the shared virulence mechanism utilized by both Yersinia pestis and Pseudomonas aeruginosa.
Yersinia pestis, which causes pneumonic plague in healthy individuals, has the potential to be used for biologic warfare. Pseudomonas aeruginosis is an opportunistic pathogen that causes severe pneumonia in immunocompromised patients. There is evidence that these two pathogens use a highly homologous virulence mechanism, the type III secretion system. The type III secretion systems of both Yersinia and P. aeruginosa possess a protein named V-antigen which can be used as a target for immunotherapy against bioterrorism and opportunistic infections. This article summarizes the recent progress of V-antigen studies in Yersinia and P. aeruginosa.
Amino Acid Sequence↗
Pseudomonas aeruginosa causes acute lung injury via the catalytic activity of the patatin-like phospholipase domain of ExoU.
OBJECTIVE: Acute lung injury in Pseudomonas aeruginosa pneumonia depends primarily on ExoU toxin being delivered directly into the eukaryotic cell cytosol through the type III secretion system. The amino-acid sequence of ExoU has a potato patatin-like phospholipase domain, similar to the sequence of mammalian Ca-independent phospholipase A2. We examined whether the acute lung injury caused by cytotoxic P. aeruginosa was dependent on the patatin-like phospholipase domain of ExoU. DESIGN: Laboratory investigation using an established mouse model for P. aeruginosa pneumonia with quantitative measurements of acute lung injury and mortality. SETTING: University experimental research laboratory. SUBJECTS: Balb/c mice. INTERVENTIONS: First, a site-directional mutation was introduced in the predicted catalytically active site of the patatin-like phospholipase domain of recombinant ExoU protein. The effect of the mutation on the catalytic activity of ExoU was tested by the in vitro lysophospholipase A assay. Second, the same site-directional mutation was introduced into the exoU gene of P. aeruginosa PA103. Mice were intratracheally infected with either a wild-type P. aeruginosa strain PA103 or an isogenic mutant containing the mutation in exoU. Acute epithelial lung injury, lung edema, bacteremia, and mortality were evaluated quantitatively. MEASUREMENTS AND MAIN RESULTS: Recombinant ExoU had lysophospholipase A activity. Site-directional mutations in the predicted catalytic site of ExoU caused a loss of the lysophospholipase A activity. Whereas the airspace instillation of PA103 caused acute lung injury and death of the infected mice, the airspace instillation of isogenic mutants secreting catalytically inactive ExoU were noncytotoxic and did not cause acute lung injury or death of the infected mice. CONCLUSION: Virulent P. aeruginosa causes acute lung injury and death by the cytotoxic activity derived from the patatin-like phospholipase domain of ExoU.
Acute Disease↗
V-antigen genotype and phenotype analyses of clinical isolates of Pseudomonas aeruginosa.
The pcrV genotype was analyzed in clinical isolates of Pseudomonas aeruginosa which showed a negative phenotype for secretion of V-antigen PcrV. The suppression of PcrV secretion in these isolates was due not to a lack of the pcrV gene but rather to suppression of PcrV expression.
Adult↗
Effects of monoclonal anti-PcrV antibody on Pseudomonas aeruginosa-induced acute lung injury in a rat model.
BACKGROUND: The effects of the murine monoclonal anti-PcrV antibody Mab166 on acute lung injury induced by Pseudomonas aeruginosa were analyzed in a rat model. METHODS: Lung injury was induced by the instillation of P. aeruginosa strain PA103 directly into the left lungs of anesthetized rats. One hour after the bacterial instillation, rabbit polyclonal anti-PcrV IgG, murine monoclonal anti-PcrV IgG Mab166 or Mab166 Fab-fragments were administered intratracheally directly into the lungs. The degree of alveolar epithelial injury, amount of lung edema, decrease in oxygenation and extent of lung inflammation by histology were evaluated as independent parameters of acute lung injury. RESULTS: These parameters improved in rats that had received intratracheal instillation of either rabbit polyclonal anti-PcrV IgG, murine monoclonal anti-PcrV IgG Mab166 or Mab166 Fab-fragments in comparison with the control group. CONCLUSION: Mab166 and its Fab fragments have potential as adjuvant therapy for acute lung injury due to P. aeruginosa pneumonia.
Journal Article↗
Perioperative anesthesia issues in the elderly.
Surgical procedures on geriatric patients are not always benign, but postoperative mortality and morbidity is improving. Optimal care depends on our ability to recognize potential risk factors and intervene in a positive manner. Not all the data are complete, and we are missing several key randomized trials, but investigators have identified many areas for possible intervention. Hopefully, in the near future, more concrete recommendations can be given for this very large and important topic of perioperative anesthetic issues in the elderly.
Adrenergic beta-Antagonists↗
Predicting mortality in acute respiratory distress syndrome: circulatory system knows best.
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APACHE↗
Protein binding between PcrG-PcrV and PcrH-PopB/PopD encoded by the pcrGVH-popBD operon of the Pseudomonas aeruginosa type III secretion system.
Of the proteins encoded by the pcrGVH-popBD operon of the Pseudomonas aeruginosa type III secretion system, PcrG bound to PcrV and PcrH bound to PopB/PopD. In addition, Yersinia LcrG bound to PcrV, and Yersinia LcrH bound to PopD. The results imply a highly functional conservation of type III secretion between P. aeruginosa and Yersinia species.
Animals↗
O-antigen serotypes and type III secretory toxins in clinical isolates of Pseudomonas aeruginosa.
The association of O-antigen serotypes with type III secretory toxins was analyzed in 99 clinical isolates of Pseudomonas aeruginosa. Isolates secreting ExoU were frequently serotyped as O11, but none were serotype O1. Most of the isolates that were nontypeable for O antigen did not secrete type III secretory toxins.
Bacterial Proteins↗
Single-nucleotide-polymorphism mapping of the Pseudomonas aeruginosa type III secretion toxins for development of a diagnostic multiplex PCR system.
We mapped the coding single nucleotide polymorphisms in four toxin genes-exoS, exoT, exoU, and exoY-of the Pseudomonas aeruginosa type III secretion system among several clinical isolates. We then used this information to design a multiplex PCR assay based on the simultaneous amplification of fragments of these genes. Eight strains of known genotype were used to test our multiplex PCR method, which showed 100% sensitivity and specificity in this small sample size. This assay appears to be promising for the rapid and accurate genotyping of the presence of these genes in clinical strains of P. aeruginosa.
Bacterial Typing Techniques↗
Generation and characterization of a protective monoclonal antibody to Pseudomonas aeruginosa PcrV.
Pseudomonas aeruginosa is a gram-negative pathogen causing life-threatening infections. Lung injury and the development of sepsis depend largely on the expression of type III secretion system (TTSS) virulence. TTSS functions as a molecular syringe to deliver toxins directly to the cytosol of cells, inhibit innate immune mechanisms, and prevent bacterial clearance. Polyclonal antibodies that bind to PcrV of P. aeruginosa inhibit the delivery of type III toxins and enhance the clearance of bacteria during acute lung infections. PcrV is a homologue of LcrV, a protective antigen in the Yersinia TTSS and an integral component of TTSS. In this study, a murine monoclonal antibody (MAb) to PcrV was generated: MAb 166, which is protective against P. aeruginosa when coinstilled with the bacterial inoculum or intraperitoneally transferred to mice. Fab fragments from MAb 166 prevent sepsis and death. The epitope bound by MAb 166 was mapped to the carboxyl-terminus of PcrV.
Animals↗
Effects of Cl2MDP-encapsulating liposomes in a murine model of Pseudomonas aeruginosa-induced sepsis.
Pseudomonas aeruginosa is a pathogen that frequently causes acute lung injury, bacteremia and sepsis in critically ill patients. As tissue macrophages are a major producer of inflammatory mediators that contribute to septic physiology, and are essential for eliminating bacteria from the circulation, we investigated the role of tissue macrophages in the generation of both inflammatory and anti-inflammatory cytokines in septic shock by using our mouse model of P. aeruginosa pneumonia. To see the effects of tissue macrophage depletion, we intravenously injected dichloromethylene-diphosphonate (Cl2MDP)-encapsulating liposomes in mice. Two days after the liposome injection, we instilled cytotoxic P. aeruginosa (PA103) into the lung that disseminates and causes septic shock. After the infection, we collected blood and bronchoalveolar lavage fluids. The samples were then analyzed for TNF-alpha, MIP-2, and IL-10 concentration. We compared these results to control mice that received either liposomes without Cl2MDP or phosphate buffered saline alone. Plasma TNF-alpha, MIP-2, and IL-10 levels were significantly decreased in the tissue macrophage-depleted mice compared to the control groups of mice. Although depletion of tissue macrophages by Cl2MDP-liposome administration did not affect the severity of bacteremia or the survival of infected mice, these results imply that tissue macrophages have a major role in the production of both proinflammatory and anti-inflammatory cytokines in the circulation and in the causing septic physiology associated with P. aeruginosa pneumonia.
Animals↗