Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036690 (sepsis)
 59,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We examined the influence of sepsis on the expression and activity of the calpain and caspase systems in skeletal muscle. Sepsis was induced in rats by cecal ligation and puncture (CLP). Control rats were sham operated. Calpain activity was determined by measuring the calcium-dependent hydrolysis of casein and by casein zymography. The activity of the endogenous calpain inhibitor calpastatin was measured by determining the inhibitory effect on calpain activity in muscle extracts. Protein levels of mu- and m-calpain and calpastatin were determined by Western blotting, and calpastatin mRNA was measured by real-time PCR. Caspase-3 activity was determined by measuring the hydrolysis of the fluorogenic caspase-3 substrate Ac-DEVD-AMC and by determining protein and mRNA expression for caspase-3 by Western blotting and real-time PCR, respectively. In addition, the role of calpains and caspase-3 in sepsis-induced muscle protein breakdown was determined by measuring protein breakdown rates in the presence of specific inhibitors. Sepsis resulted in increased muscle calpain activity caused by reduced calpastatin activity. In contrast, caspase-3 activity, mRNA levels, and activated caspase-3 29-kDa fragment were not altered in muscle from septic rats. Sepsis-induced muscle proteolysis was blocked by the calpain inhibitor calpeptin but was not influenced by the caspase-3 inhibitor Ac-DEVD-CHO. The results suggest that sepsis-induced muscle wasting is associated with increased calpain activity, secondary to reduced calpastatin activity, and that caspase-3 activity is not involved in the catabolic response to sepsis.
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PMID:Sepsis stimulates calpain activity in skeletal muscle by decreasing calpastatin activity but does not activate caspase-3. 1556 79

Caspase-1-deficient (-/-) mice are protected against sepsis-induced hypotension and mortality. We investigated the role of caspase-1 and its associated cytokines in a nonhypotensive model of endotoxemic acute renal failure (ARF). Mice were injected intraperitoneally with 2.5 mg of LPS that induces endotoxemic ARF. On immunoblot analysis of whole kidney, there was an increase in caspase-1 protein in LPS-treated mice compared with vehicle-treated controls. In LPS-treated mice, the glomerular filtration rate (GFR) was significantly higher in caspase-1 -/- vs. wild-type mice at 16 and 36 h after LPS. To determine the mechanism of this protection, the caspase-1-activated cytokines IL-1beta and IL-18 were investigated. IL-1beta and IL-18 protein were significantly increased in the kidneys of LPS- vs. vehicle-treated mice. To determine the role of these cytokines, mice were treated with recombinant IL-1 receptor antagonist (IL-1Ra) or IL-18-neutralizing antiserum. In LPS-treated mice, GFR was not different in IL-1Ra-treated or IL-18-neutralizing antiserum-treated or combination therapy (IL-1Ra plus IL-18-neutralizing antiserum-treated) compared with control mice. In addition, tubular cell apoptosis, neutrophil infiltration, myeloperoxidase activity, caspase-3 activity, and calpain activity were not different between wild-type and caspase-1 -/- mice with endotoxemic ARF. In LPS- vs. vehicle-treated wild-type mice, renal IL-1alpha was significantly increased. In both LPS- and vehicle-treated caspase-1 -/- mice, renal IL-1alpha was very low. In summary, caspase-1 -/- mice are functionally protected against endotoxemic ARF. Neutralization of IL-1beta and IL-18 is not functionally protective. The role of the intracellular proinflammatory cytokine IL-1alpha in endotoxemic ARF merits further study.
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PMID:Endotoxemic acute renal failure is attenuated in caspase-1-deficient mice. 1564 89

We hypothesized that modulation of endothelin-converting enzyme-1 (ECE-1) activity would affect phosphorylation of p38-mitogen activated protein kinase (p38-MAPK) and potentiate apoptosis in adult rat ventricular myocytes (ARVMs) during sepsis. The activity of ECE-1 in ARVMs was altered by increasing the substrate availability for ECE-1 by exogenous administration of bigendothelin-1 (bigET-1, 100 nM) and by inhibiting ECE-1 using FR901533 (10 microM) for 24-h. FR901533 significantly decreased the concentration of ET-1 in both sham and sepsis groups. FR901533 decreased p38-MAPK phosphorylation in sepsis but not in sham group. BigET-1 upregulated p38-MAPK phosphorylation, produced hypertrophy, decreased cell viability and reversed FR901533-induced down-regulation of p38-MAPK phosphorylation in both groups. Although, FR901533 did not affect cell cross-sectional area, it significantly reduced the viability of ARVM in both groups. The peak shortening of sham ARVMs was elevated by bigET-1, FR901533 and pretreatment with FR901533 followed by bigET-1. However, the contractility of septic ARVMs was not altered by either bigET-1 or FR901533 treatments per se. Septic ARVM exhibited significantly increased caspase-3 activity at 12 and 24-h. Pretreatment with FR901533 significantly elevated caspase-3 activity in both sham and sepsis group. The data demonstrated that bigET-1-induced hypertrophy in septic ARVM correlates with an ECE-1 dependent-activation of p38-MAPK. The results suggest that non-responsiveness of ARVM to bigET-1 is due to ECE-1 dependent apoptosis. We concluded that ECE-1 may play a crucial role in ARVM dysfunction via increased caspase-3 activity and p38-MAPK phosphorylation during sepsis.
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PMID:Endothelin-converting enzyme-1-mediated signaling in adult rat ventricular myocyte contractility and apoptosis during sepsis. 1573 12

The potency of clarithromycin as immunomodulator was assessed in an experimental model of sepsis based on acute pyelonephritis by susceptible Escherichia coli. 55 rabbits were utilized; 5 for preliminary pharmacokinetic study and 50 for treatment. The latter were divided into 5 groups of treatment, A: controls; B: clarithromycin pretreatment; C: amikacin pretreatment; D: clarithromycin treatment on presentation of pulmonary oedema; and E; amikacin treatment on presentation of pulmonary oedema. Survival was recorded; tumour necrosis factor-alpha (TNFalpha), and malondialdehyde (MDA) were estimated in serum; activities of caspase-3 in monocyte cytosolic extracts were studied; and bacterial counts made in various organs. Median survival of animals of groups A, B, C, D and E was 1.0, 21.0, 12.5, 2.0 and 5.0 d, respectively. TNFalpha and MDA and monocyte caspase-3 activity of group A increased over time; no increases were detected in groups B and C. Concentrations of MDA and activities of monocytic caspase-3 were decreased after administration of clarithromycin in group D, an effect not occurring in group E. Bacterial load was decreased in renal tissue of group D compared to group A. It is concluded that intravenous clarithromycin might constitute a promising immunomodulator in sepsis even in the advent of pulmonary oedema.
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PMID:Clarithromycin: immunomodulatory therapy of experimental sepsis and acute pyelonephritis by Escherichia coli. 1576 90

The pathophysiology of sepsis-induced myocardial dysfunction still remains controversial. Macrophage migration inhibitory factor (MIF) has recently been identified as a cardiac-derived myocardial depressant factor in septic shock. Putative mechanisms by which MIF affects cardiac function are unknown. In an investigation of possible mechanisms of action, a rat model of endotoxin toxicity was designed using intraperitoneal (I/P) injection of lipopolysaccharides (LPS) with or without coinfusion of neutralizing anti-MIF or isotypic-matched antibodies. Echocardiographic evaluation revealed that MIF neutralization reversed endotoxin-induced myocardial dysfunction at 24 hours after injection. RNase protection assay (RPA) and Western blot established that MIF neutralization prevented LPS-induced mRNA expression and production of heart-derived inflammatory paracrine and autocrine cytokines such as IL-1s and IL-6. Moreover, MIF immunoneutralization increased heart Bcl-2/Bax protein ratio and suppressed endotoxin-induced release of mitochondrial cytochrome-c, as demonstrated by Western blotting. Inhibition of mitochondrial loss of cytochrome-c decreased in heart caspase-3 activity at 6 and 24 hours after injection. MIF neutralization also restored the LPS-induced deficient nuclear translocation of phospho-Akt and consequently the expression of the heart survival nuclear factor GATA-4. The restoration of the translocation/expression of survival factors by MIF inhibition resulted in lowered endotoxin-induced DNA fragmentation at 24 hours, a hallmark of downstream cardiomyocyte apoptosis. Our data indicate that early inactivation of MIF significantly reverses the imbalance of proapoptotic to prosurvival pathways and reduces acute inflammation of the heart thereby improving myocardial dysfunction induced by endotoxin.
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PMID:Endotoxin-induced myocardial dysfunction: effects of macrophage migration inhibitory factor neutralization. 1587 12

Although studies have shown increased evidence of death receptor-driven apoptosis in intestinal lymphoid cells, splenocytes, and the liver following the onset of polymicrobial sepsis, little is known about the mediators controlling this process or their pathologic contribution. We therefore attempted to test the hypothesis that the hydrodynamic administration of small interfering RNA (siRNA) against the death receptor, Fas or caspase-8, should attenuate the onset of morbidity and mortality seen in sepsis, as produced by cecal ligation and puncture (CLP). We initially show that in vivo administration of green fluorescent protein (GFP) siRNA in GFP transgenic mice results in a decrease in GFP fluorescence in most tissues. Subsequently, we also found that treating septic nontransgenic mice with siRNA targeting Fas or caspase-8 but not GFP (used as a control here) decreased the mRNA, in a sustained fashion up to 10 days, and protein expression of Fas and caspase-8, respectively. In addition, transferase-mediated dUTP (deoxyuridine triphosphate) nick end labeling (TUNEL) and active caspase-3 analyses revealed a decrease in apoptosis in the liver and spleen but not the thymus following siRNA treatment. Indices of liver damage were also decreased. Finally, the injection of Fas or caspase-8 given not only 30 minutes but up to 12 hours after CLP significantly improved the survival of septic mice.
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PMID:In vivo delivery of caspase-8 or Fas siRNA improves the survival of septic mice. 1594 15

Apoptosis of lymphoid tissues during sepsis is well documented and linked to the pathobiology of organ failure and death. In this study, we evaluated the effect of a single dose of recombinant erythropoietin (EPO) on thymic and splenic apoptosis in an endotoxic sepsis model. Young male Wistar rats were divided into 3 groups and administered intraperitoneally (IP) either normal saline; lipopolysaccharide (LPS) 10 mg/kg; or EPO (5000 U/kg) 30 min before lipopolysaccharide. Six hours following LPS administration animals were sacrificed. Apoptosis was assessed by hematoxylin-eosin staining, terminal deoxynucleotide transferase-mediated fluorescein-dUTP nick end labeling (TUNEL), and caspase-3 immunostaining. When compared with animals given LPS, animals pretreated with EPO displayed reduced splenic and thymic TUNEL positivity of 44+/-3 (p<0.05) and 143+/-4 (p<0.05) nuclei per high power field (hpf), respectively. Caspase-3 positivity was also significantly reduced in the spleen and thymus, with 31+/-4 (p<0.05) and 93+/-3 (p<0.05) positive stained nuclei per hpf, respectively. Serum nitrite levels were elevated in animals given lipopolysaccharide. Pretreatment with EPO attenuated the increase in nitrite levels; however, this did not reach statistical significance. We conclude that a single dose of recombinant erythropoietin can reduce thymic and splenic apoptosis associated with lipopolysaccharide administration.
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PMID:Erythropoietin attenuates lipopolysaccharide-induced splenic and thymic apoptosis in rats. 1608 14

Streptococcus pneumoniae is the major pathogen of community-acquired pneumonia and a common cause of otitis, meningitis and sepsis. During pneumococci infection accompanied with bacterial invasion and hematogenous spreading, the endothelium is directly targeted by pneumococci and their virulence factors. Therefore, we tested the hypothesis that pneumococci induced endothelial apoptosis. Unencapsulated R6x pneumococci strongly induced apoptosis of human endothelial cells both from lung microvasculature and umbilical vein, whereas an encapsulated strain D39 mainly led to necrotic cell death. Deletion of the gene coding for pneumolysin reduced pneumococci-induced apoptosis in HUVEC. Furthermore, N-acetyl-L-cysteine, an antioxidant thiol, significantly reduced apoptosis caused by R6x, and LDH release induced by D39, pointing to a role for reactive oxygen species in the pathogenesis. Apoptotic cells showed increased cleavage and activity of caspases 6 and 9 but only late activation of caspase 3. Programmed cell death could be strongly reduced by pan-caspase inhibitor zVAD. Reduced levels of Bcl2 and cytosolic increase of apoptosis-inducing factor in pneumococci-infected cells implicated involvement of mitochondrial death pathways. Caspase activation and apoptosis were abolished by cAMP elevation. Moreover, p38 mitogen-activated protein kinase and c-Jun NH(2)-terminal kinase were activated in pneumococci-infected cells and inhibitors of both kinases strongly reduced pneumococci-induced caspase activation and apoptosis. Hence, kinase- and caspase-dependence of pneumococci-induced endothelial apoptosis may bear relevance to novel therapeutic approaches to pneumococci-related disease.
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PMID:Streptococcus pneumoniae R6x induced p38 MAPK and JNK-mediated caspase-dependent apoptosis in human endothelial cells. 1611 18

During sepsis, endothelial cells are both a source and target of pro-inflammatory cytokines (e.g. IL-1alpha, IL-1beta, TNFalpha and others), which may be detrimental to vascular homeostasis. Our laboratory has demonstrated that Haemophilus somnus, a gram-negative pathogen of cattle that causes sepsis and vasculitis, and its lipooligosaccharide (LOS) induce caspases-3, -8 and -9 activation, and apoptosis of endothelial cells in vitro. In this study, we provide evidence that H. somnus LOS increases IL-1alpha and IL-1beta mRNA expression, and caspase-1 activation in endothelial cells. Addition of a caspase-1 inhibitor (YVAD), or incubation in a high extracellular potassium buffer (150 mM), reduced caspase-1 activation and significantly enhanced H. somnus LOS-mediated caspase-3 activation. Likewise, blocking the IL-1 type 1 receptor by addition of IL-receptor antagonist (IL-1ra) significantly enhanced LOS-mediated caspase-3 activation. Conversely, addition of exogenous recombinant bovine IL-1beta (100 ng/mL) to endothelial cells diminished LOS-mediated apoptosis. IL-1beta has been reported previously to protect numerous cell types from apoptosis by activating PI3 kinase/p-Akt signaling pathways. Addition of selective PI3 kinase inhibitors (e.g. wortmannin and LY294002) significantly enhanced LOS-mediated caspase-3 activation. Exposure of endothelial cells to IL-1beta or LOS increased pAkt protein as assessed by western blot. Overall, these results suggest that signaling through the IL-1 type 1 receptor diminishes H. somnus LOS-mediated apoptosis.
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PMID:Signaling through interleukin-1 type 1 receptor diminishes Haemophilus somnus lipooligosaccharide-mediated apoptosis of endothelial cells. 1612 94

Apoptosis and inflammation play an important role in the pathogenesis of direct/pulmonary acute lung injury (ALI). However, the role of the Fas receptor-driven apoptotic pathway in indirect/nonpulmonary ALI is virtually unstudied. We hypothesized that if Fas or caspase-8 plays a role in the induction of indirect ALI, their local silencing using small interfering RNA (siRNA) should be protective in hemorrhage-induced septic ALI. Initially, as a proof of principle, green fluorescent protein-siRNA was administered intratracheally into transgenic mice overexpressing green fluorescent protein. Twenty-four hours after siRNA delivery, lung sections revealed a significant decrease in green fluorescence. Intratracheally administered Cy-5-labeled Fas-siRNA localized primarily in pulmonary epithelial cells. Intratracheal instillation of siRNA did not induce lung inflammation via toll-like receptor or protein kinase PKR pathways as assessed by lung tissue interferon-alpha, tumor necrosis factor-alpha, and interleukin (IL)-6 levels. Mice subjected to hemorrhagic shock and sepsis received either Fas-, caspase-8-, or control-siRNA intratracheally 4 hours after hemorrhage. Fas- or caspase-8-siRNA significantly reduced lung tissue Fas or caspase-8 mRNA, respectively. Only Fas-siRNA markedly diminished lung tissue tumor necrosis factor-alpha, IL-6, IL-10, interferon-gamma, IL-12, and caspase-3 activity. Fas-siRNA also preserved alveolar architecture and reduced lung neutrophil infiltration and pulmonary epithelial apoptosis. These data indicate the pathophysiological significance of Fas activation in nonpulmonary/shock-induced ALI and the feasibility of intrapulmonary administration of anti-apoptotic siRNA in vivo.
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PMID:Silencing of Fas, but not caspase-8, in lung epithelial cells ameliorates pulmonary apoptosis, inflammation, and neutrophil influx after hemorrhagic shock and sepsis. 1631 69


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