Project description:Although respiratory distress is a common complication of severe malaria, little is known about the underlying molecular basis of lung dysfunction. Animal models have provided powerful insights into the pathogenesis of severe malaria syndromes such as cerebral malaria; however, no model of malaria-induced lung injury has been definitively established. This work used bronchoalveolar lavage (BAL), histopathology and gene expression analysis to examine the development of acute lung injury (ALI) in mice infected with Plasmodium berghei ANKA (PbA). BAL fluid of PbA-infected C57BL/6 mice revealed a significant increase in IgM and total protein prior to the development of cerebral malaria (CM), indicating disruption of the alveolar-capillary membrane barrier â the physiological hallmark of acute lung injury (ALI). In contrast to sepsis-induced ALI, BAL fluid cell counts remained constant with no infiltration of neutrophils. Histopathology showed septal inflammation without cellular transmigration into the alveolar spaces. Microarray analysis comparing malaria-induced ALI with sepsis-induced ALI identified several common gene ontology groups characterizing ALI in these models, including defense and immune response. Severity of malaria-induced ALI varied in a panel of inbred mouse strains, and development of ALI correlated with peripheral parasite burden but not CM susceptibility. CD36-/- mice, which have decreased parasite lung sequestration, were relatively protected from ALI. In summary, parasite burden and CD36-mediated sequestration in the lung are primary determinants of ALI in experimental murine malaria. Furthermore, differential susceptibility of mouse strains to malaria-induced ALI and CM indicate that distinct genetic determinants likely regulate susceptibility to these two important causes of malaria-associated morbidity and mortality. Keywords: Time course Lungs were excised immediately following euthanasia, snap-frozen in liquid nitrogen and stored at â80Â°C until use. Total RNA was extracted using Trizol reagent (Invitrogen) according to the manufacturerâs instructions, and mRNA was purified using an Oligo-dT cellulose column (NEB, Mississauga, ON) as described previously [54]. cDNA with incorporated 5-(3-aminoallyl)-2âdeoxyuridine-5â-triphosphate (AAdUTP; Sigma, Oakville ON) was reverse-transcribed from 1-2 Âµg mRNA. Purified cDNA was coupled with N-hydroxysuccinimide esters of Cy3 or Cy5 (GE Lifesciences, Baie d'Urfe QC). Cy3 and Cy5-labeled cDNA pairs and Agilent control spots were added to a final volume of 0.5ml hybridization buffer (1 M NaCl, 0.5% sodium sarcosine, 50 mM methyl ethane sulfonate (MES), pH 6.5, 33% formamide and 40Âµg salmon sperm DNA (Invitrogen)). Hybridizations were performed in Agilent hybridization (Agilent, Palo Alto CA) chambers at 42Â°C with rotation for 18-24 hours. Slides were washed in 6X SSPE, 0.005% sarcosine, followed by 0.06X SSPE, allowed to dry and scanned with a 4000A microarray scanner (Axon Instruments, Union City CA). TIFF images were quantified with GenePix (Axon Instruments). Variance stabilizing normalization [55] and loess smoothing were applied in Bioconductor [56] and the data were transformed to log2 scale. Each array was hybridized with cDNA transcribed from an RNA pool of 5 C57BL/6 mice per timepoint (Day 0 and 6) and technical replicates (dye-swap) experiments were performed for both time points.

Project description:We have previously demonstrated that pre-B-cell colony enhancing factor (PBEF) ais a biomarker in sepsis and sepsis-induced acute lung injury (ALI) with genetic variants conferring ALI susceptibility118. In the current study, we explored the mechanistic participation of PBEF in ALI and ventilator-induced associated lung injury (VIALI). Initial in vitro studies and demonstrated rhPBEF aas a direct rat neutrophil chemotactic factor in vitro producing marked in vivo increases in BAL leukocytes (PMNs) in vivo following (intratracheal injection (,IT) in C57B6 mice. These latter changes were accompanied by increased BAL levels of the PMN chemoattractants (, KC and MIP2), and modest changes in lung vascular and but were not associated with significant increasesin alveolar permeability. We next explored the potential synergism between rhPBEF administration (IT) and a mechanical ventilation model of modest VILI lung injury (4 hours, 30 ml/kg tidal volume). We and observed dramatic synergistic increases in BAL PMNs, and both BAL protein and cytokine levels (IL-6, TNF-?, KC). Gene expression profiling Microarray analysis further supported a major role for PBEF in the induction of gene modules associated with ALI and VALI (NFkB pathway, leukocyte extravasation, apoptosis, toll receptor signaling). Finally, we exposed wild type and heterozygous PBEF+/- mice (targeted deletion of a single PBEF allele deletion) to a model of severe VILImechanical ventilation-induced lung injury (4 hours, 40 ml/kg tidal volume). PBEF+/- mice were significantly protected from VIALI-associated increases in BAL protein and BAL IL-6 levels and exhibited significantly reduced expression of ALI-associated gene expression modules. Together, these results indicate that PBEF is a key inflammatory mediator intimately involved in both the development and severity of ventilator-induced ALI. Experiment Overall Design: animals were treated by PBS, rhPBEF (IT administration), VILI (4 hours, 30 ml/kg tidal volume), or both.

Project description:We have previously demonstrated that pre-B-cell colony enhancing factor (PBEF) ais a biomarker in sepsis and sepsis-induced acute lung injury (ALI) with genetic variants conferring ALI susceptibility118. In the current study, we explored the mechanistic participation of PBEF in ALI and ventilator-induced associated lung injury (VIALI). Initial in vitro studies and demonstrated rhPBEF aas a direct rat neutrophil chemotactic factor in vitro producing marked in vivo increases in BAL leukocytes (PMNs) in vivo following (intratracheal injection (,IT) in C57B6 mice. These latter changes were accompanied by increased BAL levels of the PMN chemoattractants (, KC and MIP2), and modest changes in lung vascular and but were not associated with significant increasesin alveolar permeability. We next explored the potential synergism between rhPBEF administration (IT) and a mechanical ventilation model of modest VILI lung injury (4 hours, 30 ml/kg tidal volume). We and observed dramatic synergistic increases in BAL PMNs, and both BAL protein and cytokine levels (IL-6, TNF-?, KC). Gene expression profiling Microarray analysis further supported a major role for PBEF in the induction of gene modules associated with ALI and VALI (NFkB pathway, leukocyte extravasation, apoptosis, toll receptor signaling). Finally, we exposed wild type and heterozygous PBEF+/- mice (targeted deletion of a single PBEF allele deletion) to a model of severe VILImechanical ventilation-induced lung injury (4 hours, 40 ml/kg tidal volume). PBEF+/- mice were significantly protected from VIALI-associated increases in BAL protein and BAL IL-6 levels and exhibited significantly reduced expression of ALI-associated gene expression modules. Together, these results indicate that PBEF is a key inflammatory mediator intimately involved in both the development and severity of ventilator-induced ALI. We used microarrays to detail the global programme of gene expression induced by rhPBEF treatment and VALI. Experiment Overall Design: animals were treated by PBS, rhPBEF (IT administration), VILI (4 hours, 30 ml/kg tidal volume), or both.

Project description:With advances in supportive therapy in the last two decades, mortality rates from ALI/ARDS have improved somewhat, but remain around 30 to 40% with significant morbidity in survivors. Several promising treatments are in various stages of evaluation, but many have failed to prove beneficial in large randomized clinical trials (RCT). The first definitive step forward in ALI therapeutics occurred recently as a result of a large RCT demonstrating a mortality decrease from 40 to 31% with the use of low-volume ventilation strategies. From this, it is clear that the opportunity for successful intervention in ALI exists. However, therapeutic advances remain frustrated by the lack of complete understanding of ALI pathophysiology. This stresses the importance of integrating basic and clinical research of the molecular pathogenesis of this disease. The conclusions of a recent National Heart, Lung, and Blood Institute (NHLBI) Working Group on ALI support this type of research as a priority for future investigations of ALI. One of the areas of research given priority by this ALI Working Group is the issue of ALI severity progression and the role of cells of innate immunity in this process. Currently, the processes that determine which ALI patients progress to ARDS and which do not are unclear. As with many phenotype differences, there is most likely a genetic component involved. The basis for this has been demonstrated. For example, a surfactant protein B (SP-B) polymorphism appears to increase a patient’s risk of developing ALI from pneumonia. Additionally, a polymorphism in the promoter region of the gene for interleukin-6 (IL-6) has been associated with a poor prognosis in patients with ARDS. Understanding the intracellular processes of these genes and the cells expressing them in ALI progression could lead to the identification of molecular markers of ALI severity and eventually to the development of targeted therapies. An examination of genetically uniform animals will provide a clearer insight into the interaction between immune cells in ALI progression as well as guide future human experiments. Keywords: Time Series Design, ALI - acute lung injury, ARDS - acute respiratory distress syndrome, CLP - cecal ligation and puncture

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Imbalance of Intestinal Flora Activates Inflammatory Response Contributing to Acute Lung Injury

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