The Experts below are selected from a list of 23538 Experts worldwide ranked by ideXlab platform
Hartmut Jaeschke - One of the best experts on this subject based on the ideXlab platform.
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protection against tnf induced liver Parenchymal Cell apoptosis during endotoxemia by a novel caspase inhibitor in mice
Toxicology and Applied Pharmacology, 2000Co-Authors: Hartmut Jaeschke, Anwar Farhood, Sui Xiong Cai, Ben Y Tseng, Mary Lynn BajtAbstract:Abstract Excessive apoptotic Cell death is implicated in a growing number of acute and chronic disease states. Caspases are critical for the intraCellular signaling pathway leading to apoptosis. The aim of this investigation was to evaluate the efficacy and the mechanism of action of the novel caspase inhibitor CV1013 in a well-characterized model of TNF-induced apoptosis. Administration of 700 mg/kg galactosamine/100 μg/kg endotoxin (Gal/ET) induced hepatoCellular apoptosis in C3Heb/FeJ mice as indicated by increased caspase-3 activity (706% above controls) and enhanced DNA fragmentation (3400% above controls) at 6 h. In addition, apoptosis was aggravated by the neutrophil-induced injury at 7 h (ALT activities: 4220 ± 960 U/L and 48 ± 4% necrosis). All animals died 8–12 h after Gal/ET treatment from shock and liver failure. A dose of 10 or 1 mg/kg of CV1013 administered three times (3, 4.5, and 5.5 h after Gal/ET) effectively prevented caspase-3 activation and Parenchymal Cell apoptosis at 6 h as well as the subsequent neutrophil-induced aggravation of the injury at 7 h after Gal/ET treatment. Animals treated with 10 mg/kg CV1013 survived for 24 h without liver injury. CV1013 reduced the processing of caspase-3 and caspase-8. This suggests that CV1013 may have inhibited the small amount of active caspase-8 generated at the receptor level. Because of the multiple amplification loops used to activate the entire caspase cascade, blocking the initial intraCellular signal by CV1013 was highly effective in preventing apoptotic Cell death. CV1013 has therapeutic potential for disease states with excessive apoptosis.
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protection against fas receptor mediated apoptosis in hepatocytes and nonParenchymal Cells by a caspase 8 inhibitor in vivo evidence for a postmitochondrial processing of caspase 8
Toxicological Sciences, 2000Co-Authors: Mary Lynn Bajt, Judy A Lawson, Jaspreet S Gujral, Steven L. Vonderfecht, Hartmut JaeschkeAbstract:Lymphocytes can kill target Cells including hepatocytes during various inflammatory diseases by Fas receptor-mediated apopto- sis. Caspase-8 is activated at the receptor level, thereby initiating the processing of downstream effector caspases. The aim of this study was to investigate the time course of caspase-8 activation and to evaluate the efficacy of the caspase-8 inhibitor IETD-CHO in a model of Fas-induced apoptosis in vivo. C3Heb/FeJ mice were treated with the anti-Fas antibody Jo-2 (0.6 mg/kg). Western blot analysis demonstrated increased cytochrome c in the cytosol (20 min), which was followed by the progressive activation of caspase-3, -9 (40 -120 min), and caspase-8 (120 min). At 90 and 120 min, extensive hemorrhage was observed, indicating damage to sinusoidal lining Cells. In addition, high plasma ALT levels (997 6 316 U/L) and histological evaluation indicated severe Parenchymal Cell injury. Parenchymal and nonParenchymal Cells showed a similar increase in caspase-3 activity and DNA fragmen- tation. Treatment with IETD-CHO (10 mg/kg) attenuated the increase in caspase-3 activity and DNA fragmentation by 80 -90% and completely prevented hemorrhage and Parenchymal Cell dam- age. IETD-CHO also prevented the early release of mitochondrial cytochrome c and the processing of caspase-3, -8, and -9. Thus, our data support the hypothesis that Fas-mediated apoptosis is depen- dent on caspase-8 activation in hepatocytes and nonParenchymal Cells. However, the bulk of procaspase-8 is processed late, suggest- ing that only a small amount of procaspase-8 may actually be activated at the Fas receptor. This initial signal may be amplified by further activation of caspase-8 by effector caspases, i.e., after mitochondrial activation. Caspase-8 is a promising therapeutic
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Protection against Fas Receptor–Mediated Apoptosis in Hepatocytes and NonParenchymal Cells by a Caspase-8 Inhibitor in Vivo: Evidence for a Postmitochondrial Processing of Caspase-8
Toxicological Sciences, 2000Co-Authors: Mary Lynn Bajt, Judy A Lawson, Jaspreet S Gujral, Steven L. Vonderfecht, Hartmut JaeschkeAbstract:Lymphocytes can kill target Cells including hepatocytes during various inflammatory diseases by Fas receptor-mediated apopto- sis. Caspase-8 is activated at the receptor level, thereby initiating the processing of downstream effector caspases. The aim of this study was to investigate the time course of caspase-8 activation and to evaluate the efficacy of the caspase-8 inhibitor IETD-CHO in a model of Fas-induced apoptosis in vivo. C3Heb/FeJ mice were treated with the anti-Fas antibody Jo-2 (0.6 mg/kg). Western blot analysis demonstrated increased cytochrome c in the cytosol (20 min), which was followed by the progressive activation of caspase-3, -9 (40 -120 min), and caspase-8 (120 min). At 90 and 120 min, extensive hemorrhage was observed, indicating damage to sinusoidal lining Cells. In addition, high plasma ALT levels (997 6 316 U/L) and histological evaluation indicated severe Parenchymal Cell injury. Parenchymal and nonParenchymal Cells showed a similar increase in caspase-3 activity and DNA fragmen- tation. Treatment with IETD-CHO (10 mg/kg) attenuated the increase in caspase-3 activity and DNA fragmentation by 80 -90% and completely prevented hemorrhage and Parenchymal Cell dam- age. IETD-CHO also prevented the early release of mitochondrial cytochrome c and the processing of caspase-3, -8, and -9. Thus, our data support the hypothesis that Fas-mediated apoptosis is depen- dent on caspase-8 activation in hepatocytes and nonParenchymal Cells. However, the bulk of procaspase-8 is processed late, suggest- ing that only a small amount of procaspase-8 may actually be activated at the Fas receptor. This initial signal may be amplified by further activation of caspase-8 by effector caspases, i.e., after mitochondrial activation. Caspase-8 is a promising therapeutic
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glutathione peroxidase deficient mice are more susceptible to neutrophil mediated hepatic Parenchymal Cell injury during endotoxemia importance of an intraCellular oxidant stress
Hepatology, 1999Co-Authors: Hartmut Jaeschke, Judy A Lawson, Michael A Fisher, Anwar FarhoodAbstract:Neutrophils contribute to hepatoCellular injury in a number of acuteinflammatory reactions. However, the molecular mechanism of Parenchymal Cell injury remains controversial. To address the issue of whether or not reactive oxygen species (ROS) are important in the injury process, we used the galactosamine/endotoxin (Gal/ET) model of acute liver failure, which involves a neutrophil-mediated Parenchymal Cell injury. In C3Heb/FeJ mice, Gal/ET induced a significant increase of hepatic and plasma levels of glutathione disulfide (GSSG), an indicator of oxidant stress, selectively during the neutrophil-mediated injury phase. In glutathione peroxidase–deficient mice (Gpx1−/−), Gal/ET or Gal/tumor necrosis factor α (TNF-α) caused more severe neutrophil-mediated liver injury compared with wild-type animals. However, there was no significant difference in other critical parameters, e.g., activation of the transcription factor, nuclear factor-κB (NF-κB), and soluble interCellular adhesion molecule-1 (sICAM-1), Parenchymal Cell apoptosis, and neutrophil sequestration in the liver. Our results suggest that neutrophil-derived ROS are responsible for an intraCellular oxidant stress in hepatocytes after Gal/ET treatment. Because of the higher susceptibility of Gpx1−/− mice to a neutrophil-mediated injury, we conclude that peroxides generated by neutrophils diffused into hepatocytes and contributed to Parenchymal Cell death in vivo. Thus, strengthening defense mechanisms against ROS in target Cells can attenuate excessive inflammatory injury without affecting host defense reactions
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Parenchymal Cell apoptosis as a signal for sinusoidal sequestration and transendothelial migration of neutrophils in murine models of endotoxin and fas antibody induced liver injury
Hepatology, 1998Co-Authors: Judy A Lawson, Michael A Fisher, Anwar Farhood, Carol A Simmons, Hartmut JaeschkeAbstract:Endotoxin (ET) induces neutrophil sequestration in hepatic sinusoids, the activation of proinflammatory transcription factors (nuclear factor κB [NF-κB]) with up-regulation of adhesion molecules on sinusoidal endothelial Cells and hepatocytes. However, if galactosamine (Gal) is co-administered with ET, neutrophils transmigrate and attack Parenchymal Cells. This suggests that a signal from Parenchymal Cells triggers neutrophil transmigration. In this study, we tested the hypothesis that Parenchymal Cell apoptosis may induce neutrophil transendothelial migration in the Gal/ET model. Treatment of C3Heb/FeJ mice with 700 mg/kg Gal and 100 μg/kg ET induced tumor necrosis factor α (TNF-α) formation (13.25 ± 0.75 ng/mL) and hepatic NF-κB activation at 90 minutes; the generation of the C-X-C chemokine KC (2.86 ± 0.30 ng/mL at 5 hours); sinusoidal neutrophil sequestration (380 ± 21 polymorphonuclear leukocytes/50 high-power fields) and apoptosis (925% ± 29% increase of DNA fragmentation; and a 45-fold increase of terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling (TUNEL)-positive Cells) at 6 hours, followed by transmigration of neutrophils and development of substantial necrosis (38% ± 3% of hepatocytes; alanine transaminase [ALT]: 1,500 ± 300 U/L) at 7 hours. Administration of uridine (1,000 mg/kg) did not reduce plasma levels of TNF-α and KC, NF-κB activation, or polymorphonuclear leukocyte sequestration, but attenuated apoptosis by 90% to 94%. In these livers, neutrophils did not transmigrate and liver injury was prevented (necrosis: <5%; ALT: 40 ± 3 U/L). However, massive apoptosis and liver injury initiated by the anti-Fas antibody, Jo2, did not recruit neutrophils into the liver. We conclude that excessive Parenchymal Cell apoptosis represents an important signal for transmigration of primed neutrophils sequestered in sinusoids during endotoxemia in vivo. However, apoptosis per se does not cause neutrophil sequestration in the liver vasculature.
Joseph P Grande - One of the best experts on this subject based on the ideXlab platform.
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disparate roles of marrow and Parenchymal Cell derived tlr4 signaling in murine lps induced systemic inflammation
Scientific Reports, 2012Co-Authors: Justin E Juskewitch, Jeffrey L Platt, Bruce E Knudsen, Keith L Knutson, Gregory J Brunn, Joseph P GrandeAbstract:Disparate roles of marrow- and Parenchymal Cell-derived TLR4 signaling in murine LPS-induced systemic inflammation
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lps induced murine systemic inflammation is driven by Parenchymal Cell activation and exclusively predicted by early mcp 1 plasma levels
American Journal of Pathology, 2012Co-Authors: Justin E Juskewitch, Jeffrey L Platt, Bruce E Knudsen, Keith L Knutson, Gregory J Brunn, Karl A Nath, Joseph P GrandeAbstract:Systemic inflammation remains a major cause of morbidity and mortality in the United States, across many disease processes. One classic murine model to study this syndrome is lipopolysaccharide (LPS)–induced Toll-like receptor 4 (TLR4)–dependent systemic inflammation. Although most studies have focused on inflammatory Cell TLR4 responses, Parenchymal Cells also express TLR4. Our objective was to define the in vivo role of Parenchymal- versus marrow-derived Cell activation via TLR4 during LPS-induced inflammation. Mice bearing TLR4 on Parenchymal Cells only, marrow-derived Cells only, both, or neither were generated using bone marrow transplantation. Mortality occurred only in mice that had TLR4 expression on their Parenchymal Cells. Before onset, virtually all major plasma cytokines and blood neutrophil responses were related to marrow-derived Cell activation via TLR4. The only cytokine predictive of oncoming systemic inflammation was the chemokine monocyte chemoattractant protein-1. Late blood neutrophil responses were related to the presence of TLR4 on either Parenchymal or marrow Cells, whereas plasma cytokine elevations late in LPS-induced systemic inflammation were dependent on mice having TLR4 in both Cell compartments. Parenchymal Cell activation via TLR4 is a key component of LPS-induced systemic inflammation and mortality, although most plasma cytokine levels and blood neutrophil responses were not key components. Given its unique role, future studies into monocyte chemoattractant protein-1's exact role during systemic inflammation are warranted.
Judy A Lawson - One of the best experts on this subject based on the ideXlab platform.
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protection against fas receptor mediated apoptosis in hepatocytes and nonParenchymal Cells by a caspase 8 inhibitor in vivo evidence for a postmitochondrial processing of caspase 8
Toxicological Sciences, 2000Co-Authors: Mary Lynn Bajt, Judy A Lawson, Jaspreet S Gujral, Steven L. Vonderfecht, Hartmut JaeschkeAbstract:Lymphocytes can kill target Cells including hepatocytes during various inflammatory diseases by Fas receptor-mediated apopto- sis. Caspase-8 is activated at the receptor level, thereby initiating the processing of downstream effector caspases. The aim of this study was to investigate the time course of caspase-8 activation and to evaluate the efficacy of the caspase-8 inhibitor IETD-CHO in a model of Fas-induced apoptosis in vivo. C3Heb/FeJ mice were treated with the anti-Fas antibody Jo-2 (0.6 mg/kg). Western blot analysis demonstrated increased cytochrome c in the cytosol (20 min), which was followed by the progressive activation of caspase-3, -9 (40 -120 min), and caspase-8 (120 min). At 90 and 120 min, extensive hemorrhage was observed, indicating damage to sinusoidal lining Cells. In addition, high plasma ALT levels (997 6 316 U/L) and histological evaluation indicated severe Parenchymal Cell injury. Parenchymal and nonParenchymal Cells showed a similar increase in caspase-3 activity and DNA fragmen- tation. Treatment with IETD-CHO (10 mg/kg) attenuated the increase in caspase-3 activity and DNA fragmentation by 80 -90% and completely prevented hemorrhage and Parenchymal Cell dam- age. IETD-CHO also prevented the early release of mitochondrial cytochrome c and the processing of caspase-3, -8, and -9. Thus, our data support the hypothesis that Fas-mediated apoptosis is depen- dent on caspase-8 activation in hepatocytes and nonParenchymal Cells. However, the bulk of procaspase-8 is processed late, suggest- ing that only a small amount of procaspase-8 may actually be activated at the Fas receptor. This initial signal may be amplified by further activation of caspase-8 by effector caspases, i.e., after mitochondrial activation. Caspase-8 is a promising therapeutic
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Protection against Fas Receptor–Mediated Apoptosis in Hepatocytes and NonParenchymal Cells by a Caspase-8 Inhibitor in Vivo: Evidence for a Postmitochondrial Processing of Caspase-8
Toxicological Sciences, 2000Co-Authors: Mary Lynn Bajt, Judy A Lawson, Jaspreet S Gujral, Steven L. Vonderfecht, Hartmut JaeschkeAbstract:Lymphocytes can kill target Cells including hepatocytes during various inflammatory diseases by Fas receptor-mediated apopto- sis. Caspase-8 is activated at the receptor level, thereby initiating the processing of downstream effector caspases. The aim of this study was to investigate the time course of caspase-8 activation and to evaluate the efficacy of the caspase-8 inhibitor IETD-CHO in a model of Fas-induced apoptosis in vivo. C3Heb/FeJ mice were treated with the anti-Fas antibody Jo-2 (0.6 mg/kg). Western blot analysis demonstrated increased cytochrome c in the cytosol (20 min), which was followed by the progressive activation of caspase-3, -9 (40 -120 min), and caspase-8 (120 min). At 90 and 120 min, extensive hemorrhage was observed, indicating damage to sinusoidal lining Cells. In addition, high plasma ALT levels (997 6 316 U/L) and histological evaluation indicated severe Parenchymal Cell injury. Parenchymal and nonParenchymal Cells showed a similar increase in caspase-3 activity and DNA fragmen- tation. Treatment with IETD-CHO (10 mg/kg) attenuated the increase in caspase-3 activity and DNA fragmentation by 80 -90% and completely prevented hemorrhage and Parenchymal Cell dam- age. IETD-CHO also prevented the early release of mitochondrial cytochrome c and the processing of caspase-3, -8, and -9. Thus, our data support the hypothesis that Fas-mediated apoptosis is depen- dent on caspase-8 activation in hepatocytes and nonParenchymal Cells. However, the bulk of procaspase-8 is processed late, suggest- ing that only a small amount of procaspase-8 may actually be activated at the Fas receptor. This initial signal may be amplified by further activation of caspase-8 by effector caspases, i.e., after mitochondrial activation. Caspase-8 is a promising therapeutic
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glutathione peroxidase deficient mice are more susceptible to neutrophil mediated hepatic Parenchymal Cell injury during endotoxemia importance of an intraCellular oxidant stress
Hepatology, 1999Co-Authors: Hartmut Jaeschke, Judy A Lawson, Michael A Fisher, Anwar FarhoodAbstract:Neutrophils contribute to hepatoCellular injury in a number of acuteinflammatory reactions. However, the molecular mechanism of Parenchymal Cell injury remains controversial. To address the issue of whether or not reactive oxygen species (ROS) are important in the injury process, we used the galactosamine/endotoxin (Gal/ET) model of acute liver failure, which involves a neutrophil-mediated Parenchymal Cell injury. In C3Heb/FeJ mice, Gal/ET induced a significant increase of hepatic and plasma levels of glutathione disulfide (GSSG), an indicator of oxidant stress, selectively during the neutrophil-mediated injury phase. In glutathione peroxidase–deficient mice (Gpx1−/−), Gal/ET or Gal/tumor necrosis factor α (TNF-α) caused more severe neutrophil-mediated liver injury compared with wild-type animals. However, there was no significant difference in other critical parameters, e.g., activation of the transcription factor, nuclear factor-κB (NF-κB), and soluble interCellular adhesion molecule-1 (sICAM-1), Parenchymal Cell apoptosis, and neutrophil sequestration in the liver. Our results suggest that neutrophil-derived ROS are responsible for an intraCellular oxidant stress in hepatocytes after Gal/ET treatment. Because of the higher susceptibility of Gpx1−/− mice to a neutrophil-mediated injury, we conclude that peroxides generated by neutrophils diffused into hepatocytes and contributed to Parenchymal Cell death in vivo. Thus, strengthening defense mechanisms against ROS in target Cells can attenuate excessive inflammatory injury without affecting host defense reactions
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Parenchymal Cell apoptosis as a signal for sinusoidal sequestration and transendothelial migration of neutrophils in murine models of endotoxin and fas antibody induced liver injury
Hepatology, 1998Co-Authors: Judy A Lawson, Michael A Fisher, Anwar Farhood, Carol A Simmons, Hartmut JaeschkeAbstract:Endotoxin (ET) induces neutrophil sequestration in hepatic sinusoids, the activation of proinflammatory transcription factors (nuclear factor κB [NF-κB]) with up-regulation of adhesion molecules on sinusoidal endothelial Cells and hepatocytes. However, if galactosamine (Gal) is co-administered with ET, neutrophils transmigrate and attack Parenchymal Cells. This suggests that a signal from Parenchymal Cells triggers neutrophil transmigration. In this study, we tested the hypothesis that Parenchymal Cell apoptosis may induce neutrophil transendothelial migration in the Gal/ET model. Treatment of C3Heb/FeJ mice with 700 mg/kg Gal and 100 μg/kg ET induced tumor necrosis factor α (TNF-α) formation (13.25 ± 0.75 ng/mL) and hepatic NF-κB activation at 90 minutes; the generation of the C-X-C chemokine KC (2.86 ± 0.30 ng/mL at 5 hours); sinusoidal neutrophil sequestration (380 ± 21 polymorphonuclear leukocytes/50 high-power fields) and apoptosis (925% ± 29% increase of DNA fragmentation; and a 45-fold increase of terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling (TUNEL)-positive Cells) at 6 hours, followed by transmigration of neutrophils and development of substantial necrosis (38% ± 3% of hepatocytes; alanine transaminase [ALT]: 1,500 ± 300 U/L) at 7 hours. Administration of uridine (1,000 mg/kg) did not reduce plasma levels of TNF-α and KC, NF-κB activation, or polymorphonuclear leukocyte sequestration, but attenuated apoptosis by 90% to 94%. In these livers, neutrophils did not transmigrate and liver injury was prevented (necrosis: <5%; ALT: 40 ± 3 U/L). However, massive apoptosis and liver injury initiated by the anti-Fas antibody, Jo2, did not recruit neutrophils into the liver. We conclude that excessive Parenchymal Cell apoptosis represents an important signal for transmigration of primed neutrophils sequestered in sinusoids during endotoxemia in vivo. However, apoptosis per se does not cause neutrophil sequestration in the liver vasculature.
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activation of caspase 3 cpp32 like proteases is essential for tnf α induced hepatic Parenchymal Cell apoptosis and neutrophil mediated necrosis in a murine endotoxin shock model
Journal of Immunology, 1998Co-Authors: Hartmut Jaeschke, Judy A Lawson, Michael A Fisher, Anwar Farhood, Carol Simmons, David A JonesAbstract:Endotoxin (ET)-induced liver failure is characterized by Parenchymal Cell apoptosis and inflammation leading to liver Cell necrosis. Members of the caspase family have been implicated in the signal transduction pathway of apoptosis. The aim of this study was to characterize ET-induced hepatic caspase activation and apoptosis and to investigate their effect on neutrophil-mediated liver injury. Treatment of C3Heb/FeJ mice with 700 mg/kg galactosamine (Gal) and 100 μg/kg Salmonella abortus equi ET increased caspase 3-like protease activity (Asp-Val-Glu-Asp-substrate) by 1730 ± 140% at 6 h. There was a parallel enhancement of apoptosis (assessed by DNA fragmentation ELISA and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay). In contrast, activity of caspase 1 (IL-1β-converting enzyme)-like proteases (Tyr-Val-Ala-Asp-substrate) did not change throughout the experiment. Caspase 3-like protease activity and apoptosis was not induced by Gal/ET in ET-resistant mice (C3H/HeJ). Furthermore, only murine TNF-α but not IL-1αβ increased caspase activity and apoptosis. Gal/ET caused neutrophil-dependent hepatoCellular necrosis at 7 h (area of necrosis, 45 ± 3%). Delayed treatment with the caspase 3-like protease inhibitor Z-Val-Ala-Asp-CH2F (Z-VAD) (10 mg/kg at 3 h) attenuated apoptosis by 81 to 88% and prevented liver Cell necrosis (≤5%). Z-VAD had no effect on the initial inflammatory response, including the sequestration of neutrophils in sinusoids. However, Z-VAD prevented neutrophil transmigration and necrosis. Our data indicate that activation of the caspase 3 subfamily of cysteine proteases is critical for the development of Parenchymal Cell apoptosis. In addition, excessive hepatoCellular apoptosis can be an important signal for transmigration of primed neutrophils sequestered in sinusoids.
Anwar Farhood - One of the best experts on this subject based on the ideXlab platform.
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protection against tnf induced liver Parenchymal Cell apoptosis during endotoxemia by a novel caspase inhibitor in mice
Toxicology and Applied Pharmacology, 2000Co-Authors: Hartmut Jaeschke, Anwar Farhood, Sui Xiong Cai, Ben Y Tseng, Mary Lynn BajtAbstract:Abstract Excessive apoptotic Cell death is implicated in a growing number of acute and chronic disease states. Caspases are critical for the intraCellular signaling pathway leading to apoptosis. The aim of this investigation was to evaluate the efficacy and the mechanism of action of the novel caspase inhibitor CV1013 in a well-characterized model of TNF-induced apoptosis. Administration of 700 mg/kg galactosamine/100 μg/kg endotoxin (Gal/ET) induced hepatoCellular apoptosis in C3Heb/FeJ mice as indicated by increased caspase-3 activity (706% above controls) and enhanced DNA fragmentation (3400% above controls) at 6 h. In addition, apoptosis was aggravated by the neutrophil-induced injury at 7 h (ALT activities: 4220 ± 960 U/L and 48 ± 4% necrosis). All animals died 8–12 h after Gal/ET treatment from shock and liver failure. A dose of 10 or 1 mg/kg of CV1013 administered three times (3, 4.5, and 5.5 h after Gal/ET) effectively prevented caspase-3 activation and Parenchymal Cell apoptosis at 6 h as well as the subsequent neutrophil-induced aggravation of the injury at 7 h after Gal/ET treatment. Animals treated with 10 mg/kg CV1013 survived for 24 h without liver injury. CV1013 reduced the processing of caspase-3 and caspase-8. This suggests that CV1013 may have inhibited the small amount of active caspase-8 generated at the receptor level. Because of the multiple amplification loops used to activate the entire caspase cascade, blocking the initial intraCellular signal by CV1013 was highly effective in preventing apoptotic Cell death. CV1013 has therapeutic potential for disease states with excessive apoptosis.
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glutathione peroxidase deficient mice are more susceptible to neutrophil mediated hepatic Parenchymal Cell injury during endotoxemia importance of an intraCellular oxidant stress
Hepatology, 1999Co-Authors: Hartmut Jaeschke, Judy A Lawson, Michael A Fisher, Anwar FarhoodAbstract:Neutrophils contribute to hepatoCellular injury in a number of acuteinflammatory reactions. However, the molecular mechanism of Parenchymal Cell injury remains controversial. To address the issue of whether or not reactive oxygen species (ROS) are important in the injury process, we used the galactosamine/endotoxin (Gal/ET) model of acute liver failure, which involves a neutrophil-mediated Parenchymal Cell injury. In C3Heb/FeJ mice, Gal/ET induced a significant increase of hepatic and plasma levels of glutathione disulfide (GSSG), an indicator of oxidant stress, selectively during the neutrophil-mediated injury phase. In glutathione peroxidase–deficient mice (Gpx1−/−), Gal/ET or Gal/tumor necrosis factor α (TNF-α) caused more severe neutrophil-mediated liver injury compared with wild-type animals. However, there was no significant difference in other critical parameters, e.g., activation of the transcription factor, nuclear factor-κB (NF-κB), and soluble interCellular adhesion molecule-1 (sICAM-1), Parenchymal Cell apoptosis, and neutrophil sequestration in the liver. Our results suggest that neutrophil-derived ROS are responsible for an intraCellular oxidant stress in hepatocytes after Gal/ET treatment. Because of the higher susceptibility of Gpx1−/− mice to a neutrophil-mediated injury, we conclude that peroxides generated by neutrophils diffused into hepatocytes and contributed to Parenchymal Cell death in vivo. Thus, strengthening defense mechanisms against ROS in target Cells can attenuate excessive inflammatory injury without affecting host defense reactions
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Parenchymal Cell apoptosis as a signal for sinusoidal sequestration and transendothelial migration of neutrophils in murine models of endotoxin and fas antibody induced liver injury
Hepatology, 1998Co-Authors: Judy A Lawson, Michael A Fisher, Anwar Farhood, Carol A Simmons, Hartmut JaeschkeAbstract:Endotoxin (ET) induces neutrophil sequestration in hepatic sinusoids, the activation of proinflammatory transcription factors (nuclear factor κB [NF-κB]) with up-regulation of adhesion molecules on sinusoidal endothelial Cells and hepatocytes. However, if galactosamine (Gal) is co-administered with ET, neutrophils transmigrate and attack Parenchymal Cells. This suggests that a signal from Parenchymal Cells triggers neutrophil transmigration. In this study, we tested the hypothesis that Parenchymal Cell apoptosis may induce neutrophil transendothelial migration in the Gal/ET model. Treatment of C3Heb/FeJ mice with 700 mg/kg Gal and 100 μg/kg ET induced tumor necrosis factor α (TNF-α) formation (13.25 ± 0.75 ng/mL) and hepatic NF-κB activation at 90 minutes; the generation of the C-X-C chemokine KC (2.86 ± 0.30 ng/mL at 5 hours); sinusoidal neutrophil sequestration (380 ± 21 polymorphonuclear leukocytes/50 high-power fields) and apoptosis (925% ± 29% increase of DNA fragmentation; and a 45-fold increase of terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling (TUNEL)-positive Cells) at 6 hours, followed by transmigration of neutrophils and development of substantial necrosis (38% ± 3% of hepatocytes; alanine transaminase [ALT]: 1,500 ± 300 U/L) at 7 hours. Administration of uridine (1,000 mg/kg) did not reduce plasma levels of TNF-α and KC, NF-κB activation, or polymorphonuclear leukocyte sequestration, but attenuated apoptosis by 90% to 94%. In these livers, neutrophils did not transmigrate and liver injury was prevented (necrosis: <5%; ALT: 40 ± 3 U/L). However, massive apoptosis and liver injury initiated by the anti-Fas antibody, Jo2, did not recruit neutrophils into the liver. We conclude that excessive Parenchymal Cell apoptosis represents an important signal for transmigration of primed neutrophils sequestered in sinusoids during endotoxemia in vivo. However, apoptosis per se does not cause neutrophil sequestration in the liver vasculature.
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activation of caspase 3 cpp32 like proteases is essential for tnf α induced hepatic Parenchymal Cell apoptosis and neutrophil mediated necrosis in a murine endotoxin shock model
Journal of Immunology, 1998Co-Authors: Hartmut Jaeschke, Judy A Lawson, Michael A Fisher, Anwar Farhood, Carol Simmons, David A JonesAbstract:Endotoxin (ET)-induced liver failure is characterized by Parenchymal Cell apoptosis and inflammation leading to liver Cell necrosis. Members of the caspase family have been implicated in the signal transduction pathway of apoptosis. The aim of this study was to characterize ET-induced hepatic caspase activation and apoptosis and to investigate their effect on neutrophil-mediated liver injury. Treatment of C3Heb/FeJ mice with 700 mg/kg galactosamine (Gal) and 100 μg/kg Salmonella abortus equi ET increased caspase 3-like protease activity (Asp-Val-Glu-Asp-substrate) by 1730 ± 140% at 6 h. There was a parallel enhancement of apoptosis (assessed by DNA fragmentation ELISA and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay). In contrast, activity of caspase 1 (IL-1β-converting enzyme)-like proteases (Tyr-Val-Ala-Asp-substrate) did not change throughout the experiment. Caspase 3-like protease activity and apoptosis was not induced by Gal/ET in ET-resistant mice (C3H/HeJ). Furthermore, only murine TNF-α but not IL-1αβ increased caspase activity and apoptosis. Gal/ET caused neutrophil-dependent hepatoCellular necrosis at 7 h (area of necrosis, 45 ± 3%). Delayed treatment with the caspase 3-like protease inhibitor Z-Val-Ala-Asp-CH2F (Z-VAD) (10 mg/kg at 3 h) attenuated apoptosis by 81 to 88% and prevented liver Cell necrosis (≤5%). Z-VAD had no effect on the initial inflammatory response, including the sequestration of neutrophils in sinusoids. However, Z-VAD prevented neutrophil transmigration and necrosis. Our data indicate that activation of the caspase 3 subfamily of cysteine proteases is critical for the development of Parenchymal Cell apoptosis. In addition, excessive hepatoCellular apoptosis can be an important signal for transmigration of primed neutrophils sequestered in sinusoids.
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activation of caspase 3 cpp32 like proteases is essential for tnf α induced hepatic Parenchymal Cell apoptosis and neutrophil mediated necrosis in a murine endotoxin shock model
Journal of Immunology, 1998Co-Authors: Hartmut Jaeschke, Judy A Lawson, Michael A Fisher, Anwar Farhood, Carol Simmons, David A JonesAbstract:Endotoxin (ET)-induced liver failure is characterized by Parenchymal Cell apoptosis and inflammation leading to liver Cell necrosis. Members of the caspase family have been implicated in the signal transduction pathway of apoptosis. The aim of this study was to characterize ET-induced hepatic caspase activation and apoptosis and to investigate their effect on neutrophil-mediated liver injury. Treatment of C3Heb/FeJ mice with 700 mg/kg galactosamine (Gal) and 100 microg/kg Salmonella abortus equi ET increased caspase 3-like protease activity (Asp-Val-Glu-Asp-substrate) by 1730 +/- 140% at 6 h. There was a parallel enhancement of apoptosis (assessed by DNA fragmentation ELISA and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay). In contrast, activity of caspase 1 (IL-1beta-converting enzyme)-like proteases (Tyr-Val-Ala-Asp-substrate) did not change throughout the experiment. Caspase 3-like protease activity and apoptosis was not induced by Gal/ET in ET-resistant mice (C3H/HeJ). Furthermore, only murine TNF-alpha but not IL-1alphabeta increased caspase activity and apoptosis. Gal/ET caused neutrophil-dependent hepatoCellular necrosis at 7 h (area of necrosis, 45 +/- 3%). Delayed treatment with the caspase 3-like protease inhibitor Z-Val-Ala-Asp-CH2F (Z-VAD) (10 mg/kg at 3 h) attenuated apoptosis by 81 to 88% and prevented liver Cell necrosis (< or = 5%). Z-VAD had no effect on the initial inflammatory response, including the sequestration of neutrophils in sinusoids. However, Z-VAD prevented neutrophil transmigration and necrosis. Our data indicate that activation of the caspase 3 subfamily of cysteine proteases is critical for the development of Parenchymal Cell apoptosis. In addition, excessive hepatoCellular apoptosis can be an important signal for transmigration of primed neutrophils sequestered in sinusoids.
Michael A Fisher - One of the best experts on this subject based on the ideXlab platform.
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glutathione peroxidase deficient mice are more susceptible to neutrophil mediated hepatic Parenchymal Cell injury during endotoxemia importance of an intraCellular oxidant stress
Hepatology, 1999Co-Authors: Hartmut Jaeschke, Judy A Lawson, Michael A Fisher, Anwar FarhoodAbstract:Neutrophils contribute to hepatoCellular injury in a number of acuteinflammatory reactions. However, the molecular mechanism of Parenchymal Cell injury remains controversial. To address the issue of whether or not reactive oxygen species (ROS) are important in the injury process, we used the galactosamine/endotoxin (Gal/ET) model of acute liver failure, which involves a neutrophil-mediated Parenchymal Cell injury. In C3Heb/FeJ mice, Gal/ET induced a significant increase of hepatic and plasma levels of glutathione disulfide (GSSG), an indicator of oxidant stress, selectively during the neutrophil-mediated injury phase. In glutathione peroxidase–deficient mice (Gpx1−/−), Gal/ET or Gal/tumor necrosis factor α (TNF-α) caused more severe neutrophil-mediated liver injury compared with wild-type animals. However, there was no significant difference in other critical parameters, e.g., activation of the transcription factor, nuclear factor-κB (NF-κB), and soluble interCellular adhesion molecule-1 (sICAM-1), Parenchymal Cell apoptosis, and neutrophil sequestration in the liver. Our results suggest that neutrophil-derived ROS are responsible for an intraCellular oxidant stress in hepatocytes after Gal/ET treatment. Because of the higher susceptibility of Gpx1−/− mice to a neutrophil-mediated injury, we conclude that peroxides generated by neutrophils diffused into hepatocytes and contributed to Parenchymal Cell death in vivo. Thus, strengthening defense mechanisms against ROS in target Cells can attenuate excessive inflammatory injury without affecting host defense reactions
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Parenchymal Cell apoptosis as a signal for sinusoidal sequestration and transendothelial migration of neutrophils in murine models of endotoxin and fas antibody induced liver injury
Hepatology, 1998Co-Authors: Judy A Lawson, Michael A Fisher, Anwar Farhood, Carol A Simmons, Hartmut JaeschkeAbstract:Endotoxin (ET) induces neutrophil sequestration in hepatic sinusoids, the activation of proinflammatory transcription factors (nuclear factor κB [NF-κB]) with up-regulation of adhesion molecules on sinusoidal endothelial Cells and hepatocytes. However, if galactosamine (Gal) is co-administered with ET, neutrophils transmigrate and attack Parenchymal Cells. This suggests that a signal from Parenchymal Cells triggers neutrophil transmigration. In this study, we tested the hypothesis that Parenchymal Cell apoptosis may induce neutrophil transendothelial migration in the Gal/ET model. Treatment of C3Heb/FeJ mice with 700 mg/kg Gal and 100 μg/kg ET induced tumor necrosis factor α (TNF-α) formation (13.25 ± 0.75 ng/mL) and hepatic NF-κB activation at 90 minutes; the generation of the C-X-C chemokine KC (2.86 ± 0.30 ng/mL at 5 hours); sinusoidal neutrophil sequestration (380 ± 21 polymorphonuclear leukocytes/50 high-power fields) and apoptosis (925% ± 29% increase of DNA fragmentation; and a 45-fold increase of terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling (TUNEL)-positive Cells) at 6 hours, followed by transmigration of neutrophils and development of substantial necrosis (38% ± 3% of hepatocytes; alanine transaminase [ALT]: 1,500 ± 300 U/L) at 7 hours. Administration of uridine (1,000 mg/kg) did not reduce plasma levels of TNF-α and KC, NF-κB activation, or polymorphonuclear leukocyte sequestration, but attenuated apoptosis by 90% to 94%. In these livers, neutrophils did not transmigrate and liver injury was prevented (necrosis: <5%; ALT: 40 ± 3 U/L). However, massive apoptosis and liver injury initiated by the anti-Fas antibody, Jo2, did not recruit neutrophils into the liver. We conclude that excessive Parenchymal Cell apoptosis represents an important signal for transmigration of primed neutrophils sequestered in sinusoids during endotoxemia in vivo. However, apoptosis per se does not cause neutrophil sequestration in the liver vasculature.
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activation of caspase 3 cpp32 like proteases is essential for tnf α induced hepatic Parenchymal Cell apoptosis and neutrophil mediated necrosis in a murine endotoxin shock model
Journal of Immunology, 1998Co-Authors: Hartmut Jaeschke, Judy A Lawson, Michael A Fisher, Anwar Farhood, Carol Simmons, David A JonesAbstract:Endotoxin (ET)-induced liver failure is characterized by Parenchymal Cell apoptosis and inflammation leading to liver Cell necrosis. Members of the caspase family have been implicated in the signal transduction pathway of apoptosis. The aim of this study was to characterize ET-induced hepatic caspase activation and apoptosis and to investigate their effect on neutrophil-mediated liver injury. Treatment of C3Heb/FeJ mice with 700 mg/kg galactosamine (Gal) and 100 μg/kg Salmonella abortus equi ET increased caspase 3-like protease activity (Asp-Val-Glu-Asp-substrate) by 1730 ± 140% at 6 h. There was a parallel enhancement of apoptosis (assessed by DNA fragmentation ELISA and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay). In contrast, activity of caspase 1 (IL-1β-converting enzyme)-like proteases (Tyr-Val-Ala-Asp-substrate) did not change throughout the experiment. Caspase 3-like protease activity and apoptosis was not induced by Gal/ET in ET-resistant mice (C3H/HeJ). Furthermore, only murine TNF-α but not IL-1αβ increased caspase activity and apoptosis. Gal/ET caused neutrophil-dependent hepatoCellular necrosis at 7 h (area of necrosis, 45 ± 3%). Delayed treatment with the caspase 3-like protease inhibitor Z-Val-Ala-Asp-CH2F (Z-VAD) (10 mg/kg at 3 h) attenuated apoptosis by 81 to 88% and prevented liver Cell necrosis (≤5%). Z-VAD had no effect on the initial inflammatory response, including the sequestration of neutrophils in sinusoids. However, Z-VAD prevented neutrophil transmigration and necrosis. Our data indicate that activation of the caspase 3 subfamily of cysteine proteases is critical for the development of Parenchymal Cell apoptosis. In addition, excessive hepatoCellular apoptosis can be an important signal for transmigration of primed neutrophils sequestered in sinusoids.
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activation of caspase 3 cpp32 like proteases is essential for tnf α induced hepatic Parenchymal Cell apoptosis and neutrophil mediated necrosis in a murine endotoxin shock model
Journal of Immunology, 1998Co-Authors: Hartmut Jaeschke, Judy A Lawson, Michael A Fisher, Anwar Farhood, Carol Simmons, David A JonesAbstract:Endotoxin (ET)-induced liver failure is characterized by Parenchymal Cell apoptosis and inflammation leading to liver Cell necrosis. Members of the caspase family have been implicated in the signal transduction pathway of apoptosis. The aim of this study was to characterize ET-induced hepatic caspase activation and apoptosis and to investigate their effect on neutrophil-mediated liver injury. Treatment of C3Heb/FeJ mice with 700 mg/kg galactosamine (Gal) and 100 microg/kg Salmonella abortus equi ET increased caspase 3-like protease activity (Asp-Val-Glu-Asp-substrate) by 1730 +/- 140% at 6 h. There was a parallel enhancement of apoptosis (assessed by DNA fragmentation ELISA and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay). In contrast, activity of caspase 1 (IL-1beta-converting enzyme)-like proteases (Tyr-Val-Ala-Asp-substrate) did not change throughout the experiment. Caspase 3-like protease activity and apoptosis was not induced by Gal/ET in ET-resistant mice (C3H/HeJ). Furthermore, only murine TNF-alpha but not IL-1alphabeta increased caspase activity and apoptosis. Gal/ET caused neutrophil-dependent hepatoCellular necrosis at 7 h (area of necrosis, 45 +/- 3%). Delayed treatment with the caspase 3-like protease inhibitor Z-Val-Ala-Asp-CH2F (Z-VAD) (10 mg/kg at 3 h) attenuated apoptosis by 81 to 88% and prevented liver Cell necrosis (< or = 5%). Z-VAD had no effect on the initial inflammatory response, including the sequestration of neutrophils in sinusoids. However, Z-VAD prevented neutrophil transmigration and necrosis. Our data indicate that activation of the caspase 3 subfamily of cysteine proteases is critical for the development of Parenchymal Cell apoptosis. In addition, excessive hepatoCellular apoptosis can be an important signal for transmigration of primed neutrophils sequestered in sinusoids.
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sinusoidal endothelial Cell and Parenchymal Cell injury during endotoxemia and hepatic ischemia reperfusion protection by the 21 aminosteroid tirilazad mesylate
International Hepatology Communications, 1997Co-Authors: Michael A Fisher, Leonard J Beuving, Robert Eversole, Hartmut JaeschkeAbstract:Abstract The early vascular injury in the liver was characterized in an experimental model of multiple organ failure (MOF). Significant increases of hyaluronic acid levels (660%) and plasma alanine aminotransferase activities (1050%) were observed after 20 min hepatic ischemia followed by 4 h reperfusion and injection of 0.5 mg/kg Salmonella enteritidis endotoxin at 30 min reperfusion. Morphological evaluation of sinusoids with transmission electron microscopy indicated neutrophil and Kupffer Cell activation as well as damage or loss of sinusoidal endothelial Cells. HepatoCellular injury was evident from fused microvilli and blebbed plasma membranes. Treatment with the 21-aminosteroid tirilazad mesylate (U-74006F) (2 × 3 mg/kg) reduced plasma hyaluronic acid levels by 61% and plasma transaminase activities by 69% suggesting a beneficial effect on sinusoidal endothelial Cell and Parenchymal Cell injury. This was confirmed by morphology. Our data provide morphological and functional evidence for severe injury to sinusoidal endothelium and the vascular pole of hepatocytes in this model of MOF. U-74006F significantly protected the liver against this Kupffer Cell- and neutrophil-mediated injury. Thus, U-74006F may be a promising therapeutic for liver dysfunction and failure during a local or systemic inflammatory response.
