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: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. Keywords: response to treatment and/or stress

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. Keywords: We used microarrays to detail the global programme of gene expression induced by rhPBEF treatment and VALI.

Project description:Acute lung injury (ALI), a major cause of acute respiratory failure with high morbidity and mortality, isare characterized by significant pulmonary inflammation and both alveolar and vascular barriers dysfunction. In Pprior studies have highlighted the role of nonmuscle myosin light chain kinase (nmMLCK) as an essential element of inflammatory response with MYLK polymorphisms associated withwhich alters ALI susceptibility. In the present study we sought to further define nmMLCK in acute inflammatory syndromes and examined We examined nmMLCK as a molecular target involved in increase of lung epithelial and endothelial barrier permeability. We utilized in two muirine models of inflammatory lung injury: intratracheal administration of endotoxin/lipopolysaccharide (LPS, 2.5 mg/kg) and VILI (ventilator-induced lung injury, tidal volume 40ml/kg). Two complementary strategies were used to reduce nmMLCK activity or expression. We found that membrane permeant oligopeptide, PIK, inhibited MLC kinase activity in vitro in aand displayed dose-dependent mannerinhibition of MLC kinase activity.. Intravenous delivery of PIK significantly attenuated LPS-induced lung inflammation reflected by decreasing accumulation of bronchoalveolar lavage (BAL) albumin (~ 50% reduction) as well as reduction in BAL cells, tissue MPO activity and tissue albumin in lung homogenates. A second regulatory approach explored targeting murine nmMLCK by administration of siRNA (5mg/kg) 3 days prior to LPS challenge. siRNA decreased of nmMLCK expression in lungs (~ 70% reduction) and resulted in significant attenuation LPS-induced lung inflammation (~ 40% reduction) as reflected by decreased BAL protein level and BAL cells. For targeting pulmonary vessels nmMLCK we used ACE antibody-conjugated liposomes with nmMLCK siRNA in murine ventilator-induced lung injury (VILI) model. Protein silencing of nmMLCK was evident by immunohistochemical analysis with a decrease in relative intensity of fluorescence in lung vessels compared with control animals. Furthermore, the inhibition of nmMLCK expression by siRNA in vessels significantly attenuated VILI lung injury as reflected by decreased BAL protein level (40% reduction). Finally, MLCK knockout mice were significantly protected (reduced BAL protein and albumin) when exposed to a model of severe VILI (4h, 40ml/kg tidal volume). Conclusion: the MLCK gene KO and chemical biology results indicate that the targeting of nmMLCK in vivo attenuate the severity of LPS-induced or VILI acute lung injury. We used microarrays to detail the global programme of gene expression induced by VILI in Wild type and nmMLCK-/- mouse. Experiment Overall Design: four group (n=3) of animals were treated by SB (Spontaneouse breathing) or VILI (4 hours, 30 ml/kg tidal volume) in Wild type or nmMLCK-/- animals;

Project description:Acute lung injury (ALI), a major cause of acute respiratory failure with high morbidity and mortality, isare characterized by significant pulmonary inflammation and both alveolar and vascular barriers dysfunction. In Pprior studies have highlighted the role of nonmuscle myosin light chain kinase (nmMLCK) as an essential element of inflammatory response with MYLK polymorphisms associated withwhich alters ALI susceptibility. In the present study we sought to further define nmMLCK in acute inflammatory syndromes and examined We examined nmMLCK as a molecular target involved in increase of lung epithelial and endothelial barrier permeability. We utilized in two muirine models of inflammatory lung injury: intratracheal administration of endotoxin/lipopolysaccharide (LPS, 2.5 mg/kg) and VILI (ventilator-induced lung injury, tidal volume 40ml/kg). Two complementary strategies were used to reduce nmMLCK activity or expression. We found that membrane permeant oligopeptide, PIK, inhibited MLC kinase activity in vitro in aand displayed dose-dependent mannerinhibition of MLC kinase activity.. Intravenous delivery of PIK significantly attenuated LPS-induced lung inflammation reflected by decreasing accumulation of bronchoalveolar lavage (BAL) albumin (~ 50% reduction) as well as reduction in BAL cells, tissue MPO activity and tissue albumin in lung homogenates. A second regulatory approach explored targeting murine nmMLCK by administration of siRNA (5mg/kg) 3 days prior to LPS challenge. siRNA decreased of nmMLCK expression in lungs (~ 70% reduction) and resulted in significant attenuation LPS-induced lung inflammation (~ 40% reduction) as reflected by decreased BAL protein level and BAL cells. For targeting pulmonary vessels nmMLCK we used ACE antibody-conjugated liposomes with nmMLCK siRNA in murine ventilator-induced lung injury (VILI) model. Protein silencing of nmMLCK was evident by immunohistochemical analysis with a decrease in relative intensity of fluorescence in lung vessels compared with control animals. Furthermore, the inhibition of nmMLCK expression by siRNA in vessels significantly attenuated VILI lung injury as reflected by decreased BAL protein level (40% reduction). Finally, MLCK knockout mice were significantly protected (reduced BAL protein and albumin) when exposed to a model of severe VILI (4h, 40ml/kg tidal volume). Conclusion: the MLCK gene KO and chemical biology results indicate that the targeting of nmMLCK in vivo attenuate the severity of LPS-induced or VILI acute lung injury. We used microarrays to detail the global programme of gene expression induced by VILI in Wild type and nmMLCK-/- mouse.

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Acute Lung Injury In Experimental Malaria

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