Project description:Lung transplantation remains the only viable therapy for patients with end-stage lung disease; however, full utilization of this treatment strategy is severely compromised by the lack of donor lung availability. For example, the vast majority of donor lungs available for transplantation are obtained from brain death (BD) individuals. Unfortunately, the autonomic storm which accompanies BD often results in neurogenic pulmonary edema (NPE), thereby either producing irreversible lung injury or leading to primary graft dysfunction following lung transplantation. We previously demonstrated that sphingosine 1-phosphate (S1P), a phospholipid angiogenic factor and major barrier-enhancing agent, as well as S1P analogues serve to reduce vascular permeability and ischemia/reperfusion (I/R) lung injury in rodents via ligation of the S1P1 receptor, S1PR1. As primary lung graft dysfunction is induced by lung vascular endothelial cell barrier dysfunction, we hypothesized that SEW-2871, a S1PR1 agonist, may attenuate NPE when administered to the donor shortly after BD. Significant lung injury was observed 4h after BD in a rat BD model with ~60% increases in BAL total protein, BAL cell counts, and lung tissue W/D weight ratios. In contrast, rats receiving SEW-2871 (0.1 mg/kg) 15 minutes after the induction of BD and assessed 4h later exhibited significant lung protection (~50% reduction, p=0.01) reflected by reduced BAL total protein, BAL cytokines concentrations, BAL albumin, BAL total cell count and lung tissue wet/dry (W/D) weights ratio. Microarray analysis at 4hrs revealed a global impact of both BD and SEW on lung gene expression with differential expression of a subclass of genes enriched in immune/inflammation response pathways across the 4 experimental groups. Overall, SEW served to attenuate the BD-mediated ie gene expression upregulation. Two potentially useful biomarkers, Tnf and Ccrl2, exhibited gene dysregulation by microarray analysis, which was validated by qPCR. We conclude that SEW-2871 significantly attenuates BD-induced lung injury and may serve as a potential candidate to improve human lung donor availability and transplantation outcomes. Animals were divided into four groups: sham, BD (A Fogarty catheter 4 Fr. was inserted and secured into the extradural space and inflated to induce BD), SEW (injection of SEW-2871), and BD/SEW. Three replicates each.

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:Clinically significant radiation-induced lung injury (RILI) is associated with significant morbidity and mortality and a common toxicity in patients administered thoracic radiotherapy. While the molecular etiology of RILI is poorly understood, we previously characterized a murine model of RILI in which alterations in lung endothelial barrier integrity surfaced as a potentially important pathobiologic event. In these studies, inhibition of HMG-CoA reductase activity (simvastatin) reduced murine RILI-associated lung inflammation and vascular leak and attenuated radiation-induced dysregulation of sphingolipid metabolic pathway genes identified by genome-wide lung gene expression profiling. In the present study, we test the hypothesis that sphingolipid signaling components serve as important modulators of RILI pathobiology and novel therapeutic targets. Sphingolipid involvement in murine RILI was confirmed by radiation-induced increases in lung expression of sphingosine kinase (SphK) isoforms 1 and 2 and increases in the ratio of ceramide to cumulative sphingosine-1-phosphate (S1P) and dihydro-S1P (DHS1P) levels in plasma, bronchoalveolar lavage (BAL) fluid and lung tissue following 25 Gy exposure (6 weeks). Moreover, genetically-engineered mice with either targeted deletion of SphK1 (SphK1-/-), or with reduced expression of selective members of the S1P receptor family (S1PR1+/-, S1PR2-/-, S1PR3-/-,), exhibited marked susceptibility to RILI-mediated lung inflammation. Finally, we assessed the efficacy of three potent vascular barrier-protective S1P analogues FTY720 (FTY), fTysiponate (fTyS) and SEW-2871 (SEW) in attenuating indices of RILI. The phosphonate analogue, fTyS, and to a lesser degree SEW, exhibited significant attenuation of RILI and RILI-induced gene dysregulation compared to control RILI-challenged mice (6 weeks). In contrast, FTY failed to significantly alter physiologic or genomic changes compared to RILI-challenged controls. Together, these results support the targeting of sphingolipid components as a novel and effective therapeutic strategy in RILI. Four mice were treated with PBS as a control. Three mice were treated with (S)-FTY-phosphonate (0.1mg/kg) as a drug control. Three mice were treated with SEW-2871 (0.1mg/kg) as a drug control. Three mice were treated with FTY720 (0.1mg/kg) as a drug control. Three mice were treated with administered radiation (25 Gy) alone. Three mice were treated with both administered radiation (25 Gy) and (S)-FTY-phosphonate (0.1mg/kg). Three mice were treated with both administered radiation (25 Gy) and SEW-2871 (0.1mg/kg). Three mice were treated with both administered radiation (25 Gy) and FTY720 (0.1mg/kg).

Project description:Clinically significant radiation-induced lung injury (RILI) is associated with significant morbidity and mortality and a common toxicity in patients administered thoracic radiotherapy. While the molecular etiology of RILI is poorly understood, we previously characterized a murine model of RILI in which alterations in lung endothelial barrier integrity surfaced as a potentially important pathobiologic event. In these studies, inhibition of HMG-CoA reductase activity (simvastatin) reduced murine RILI-associated lung inflammation and vascular leak and attenuated radiation-induced dysregulation of sphingolipid metabolic pathway genes identified by genome-wide lung gene expression profiling. In the present study, we test the hypothesis that sphingolipid signaling components serve as important modulators of RILI pathobiology and novel therapeutic targets. Sphingolipid involvement in murine RILI was confirmed by radiation-induced increases in lung expression of sphingosine kinase (SphK) isoforms 1 and 2 and increases in the ratio of ceramide to cumulative sphingosine-1-phosphate (S1P) and dihydro-S1P (DHS1P) levels in plasma, bronchoalveolar lavage (BAL) fluid and lung tissue following 25 Gy exposure (6 weeks). Moreover, genetically-engineered mice with either targeted deletion of SphK1 (SphK1-/-), or with reduced expression of selective members of the S1P receptor family (S1PR1+/-, S1PR2-/-, S1PR3-/-,), exhibited marked susceptibility to RILI-mediated lung inflammation. Finally, we assessed the efficacy of three potent vascular barrier-protective S1P analogues FTY720 (FTY), fTysiponate (fTyS) and SEW-2871 (SEW) in attenuating indices of RILI. The phosphonate analogue, fTyS, and to a lesser degree SEW, exhibited significant attenuation of RILI and RILI-induced gene dysregulation compared to control RILI-challenged mice (6 weeks). In contrast, FTY failed to significantly alter physiologic or genomic changes compared to RILI-challenged controls. Together, these results support the targeting of sphingolipid components as a novel and effective therapeutic strategy in RILI.

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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A Sphingosine 1-Phosphate 1 Receptor Agonist Modulates Brain Death-Induced Neurogenic Pulmonary Injury

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