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Query: UMLS:C0036690 (
sepsis
)
59,461
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Enzymes of the blood coagulation pathway enhance the inflammatory response leading to endothelial dysfunction, accounting, in part, for the vascular complications occurring in
sepsis
and cardiovascular disease. The responses of endothelial cell activation include induction of the expression of tissue factor (TF), a membrane glycoprotein that promotes thrombosis, and of E-selectin, a cell adhesion molecule that promotes inflammation. In this report, we demonstrate synergistic interactions between the coagulation factor Xa (fXa) and the proinflammatory cytokines TNF, IL-1beta, and CD40L, leading to enhanced expression of TF and E-selectin in endothelial cells. A detailed analysis of the molecular pathways that could account for this activity of fXa showed that fXa inhibited the cytokine-induced expression of dual specificity phosphatases,
MAP kinase
phosphatase-L, -4, -5, and -7, blocking a negative regulatory effect on
c-Jun N-terminal kinase
. The synergistic interaction between fXa and TNF was also involved in the inhibition of A20 and IkappaBalpha expression in the IkappaB kinase-NF-kappaB pathway. The data indicate that inhibition of negative regulatory signaling accounts for the amplification of cytokine-induced endothelial cell activation by fXa.
...
PMID:Synergistic induction of tissue factor by coagulation factor Xa and TNF: evidence for involvement of negative regulatory signaling cascades. 1610 45
Enhanced plasma levels of matrix metalloproteinase 9 (MMP-9) detected in patients with severe
sepsis
are thought to contribute to the development of organ dysfunction in endotoxemia. We have recently reported that peptidoglycan, the major wall component of gram-positive bacteria, increases MMP-9 levels in lung and liver and organ injury in the rat. Thus far, it is unclear whether MMP-9 is part of the septic response to peptidoglycan in human blood. The aim of the present study was to examine the regulation of MMP-9 by peptidoglycan in human leukocytes. The addition of peptidoglycan to whole human blood caused enhanced levels of MMP-9 after 1 h of incubation (306 vs. 75 ng/mL, P < or = 0.05) and onward, as measured by enzyme-linked immunoabsorbant assay. In neutrophil cultures, MMP-9 values increased significantly after 30 min of incubation with peptidoglycan (242 vs. 121 ng/mL, P < or = 0.05), whereas muramyl dipeptide had no effect. In contrast, adherent monocytes released insignificant amounts of MMP-9. To examine whether the released MMP-9 resulted from de novo synthesis, intracellular and secreted MMP-9 was measured during stimulation of neutrophils. The total MMP-9 values (the sum of intracellular and secreted MMP-9) before and after stimulation were mainly unaltered. The enhanced MMP-9 levels induced by peptidoglycan was attenuated by inhibitors of p38 mitogen-activated protein kinases (MAPK), (SB202190, 25 microM) and
ERK1
/2 (PD98059, 25 microM) and inhibitors of Src Tyrosine kinase (PP2, 5 microM) and PI3-K (LY294002, 25 microM).
...
PMID:Peptidoglycan of Staphylococcus aureus induces enhanced levels of matrix metalloproteinase-9 in human blood originating from neutrophils. 1613 59
Proinflammatory cytokines have been linked to depression of myocardial contractility in vivo in patients with acute septic shock and in vitro models employing isolated myocytes exposed to serum from such patients. The key pathways involved in mediating this septic organ dysfunction (cell adhesion molecule expression, inducible nitric-oxide synthase induction, and apoptosis) are known to be regulated by transcription factors STAT1, IRF1, and NF-kappaB. Utilizing a model that mimics human disease, we have demonstrated activation of the transcription factors STAT1, IRF1, and NF-kappaB in human fetal myocytes exposed to human septic serum. Both reporter and electrophoretic mobility shift assays demonstrated a 5-19-fold increase in activation of transcription factors STAT1, IRF1, and NF-kappaB in response to incubation with human septic serum. The addition of human septic serum to human fetal myocytes induced apoptosis in human fetal myocytes and activation of the
mitogen-activated protein kinase
c-Jun NH -terminal kinase and caspase 1 as measured by Western blot. These data suggest that transcription factor activation and early myocyte apoptosis play a mechanistic role in septic myocardial depression and
sepsis
-induced organ dysfunction.
...
PMID:Human serum from patients with septic shock activates transcription factors STAT1, IRF1, and NF-kappaB and induces apoptosis in human cardiac myocytes. 1622 33
Multiple intracellular signaling pathways involving kinases, transcriptional factors, and the expression of immunoregulatory mediators are altered in
sepsis
. Recent data have shown stable patterns of activation among peripheral blood mononuclear cells and neutrophils in healthy human subjects. Although polymorphisms in Toll-like receptors play a contributory role in determining cellular activation, other factors are involved as well. Increased activation of the
mitogen-activated protein kinase
protein 38, Akt, and nuclear factor (NF)-kappa B in neutrophils and other cell populations obtained at early time points in the clinical course of
sepsis
-induced acute lung injury or after accidental trauma is associated with a more-severe clinical course, suggesting that a proinflammatory cellular phenotype contributes to organ system dysfunction in such settings. Identification of patients with cellular phenotypes characterized by increased activation of NF-kappa B, Akt, and protein 38, as well as discrete patterns of gene activation, may permit identification of patients with
sepsis
who are likely to have a worse clinical outcome, thereby permitting early institution of therapies that modulate deleterious signaling pathways before organ system dysfunction develops, reducing morbidity and improving survival.
...
PMID:Alterations in cell signaling in sepsis. 1623 48
The bacterial pathogens of the genus Yersinia, the causative agents of plague,
septicemia
, and gastrointestinal syndromes, use a type III secretion system to inject virulence factors into host target cells. One virulence factor, YopJ, is essential for the death of infected macrophages and can block host proinflammatory responses by inhibiting both the nuclear factor kappaB (NF-kappaB) and
mitogen-activated protein kinase
pathways, which might be important for evasion of the host immune response and aid in establishing a systemic infection. Here, we show that YopJ is a promiscuous deubiquitinating enzyme that negatively regulates signaling by removing ubiquitin moieties from critical proteins, such as TRAF2, TRAF6, and IkappaBalpha. In contrast to the cylindromatosis tumor suppressor CYLD, which attenuates NF-kappaB signaling by selectively removing K63-linked polyubiquitin chains that activate IkappaB kinase, YopJ also cleaves K48-linked chains and thereby inhibits proteasomal degradation of IkappaBalpha. YopJ, but not a catalytically inactive YopJ mutant, promoted deubiquitination of cellular proteins and cleaved both K48- and K63-linked polyubiquitin. Moreover, an in vitro assay was established to demonstrate directly the deubiquitinating activity of purified YopJ.
...
PMID:Yersinia virulence factor YopJ acts as a deubiquitinase to inhibit NF-kappa B activation. 1630 42
Respiratory dysfunction during
sepsis
is common. However, although lung function can often be adequately supported, death frequently results from cardiovascular collapse. Despite intense investigation, the mechanism underlying the myocardial dysfunction of
sepsis
remains unclear. Macrophage migration inhibitory factor (MIF), an important cytokine released in
sepsis
and the acute respiratory distress syndrome, is a known cardiac depressant. We hypothesized that MIF released from the lung results in myocardial dysfunction during
sepsis
. In murine models of polymicrobial
sepsis
, we demonstrate a significant increase in the lungs of total and lavagable MIF between 20 and 30 h post induction of
sepsis
. At 30 h post
sepsis
, the lungs released MIF into the pulmonary circulation, increasing the plasma concentration by up to 51% in a single pass. Exogenous MIF, instilled into the lungs, increased alveolar keratinocyte-derived chemokine (KC), Macrophage inflammatory protein-2 (MIP2), and tumor necrosis factor alpha (TNFalpha) at 3 h, and plasma KC and MIP2 at 6 h postinstillation. This was associated with an increase in p38 mitogen-activated protein kinase and
c-Jun N-terminal kinase
phosphorylation. Because changes in
mitogen-activated protein kinase
activation can lead to myocardial depression, these data suggest that MIF released from the lungs may be responsible, at least in part, for the cardiac dysfunction seen in the late stages of
sepsis
.
...
PMID:Macrophage migration inhibitory factor within the alveolar spaces induces changes in the heart during late experimental sepsis. 1631 87
Glutamine (GLN) has been shown to attenuate cytokine release from LPS-stimulated human peripheral blood mononuclear cells; however, the in vivo antiinflammatory effect of GLN in polymicrobial
sepsis
and ARDS is unknown. This study evaluates the effect of GLN on inflammatory cytokine release and the pathways that may mediate antiinflammatory effects of GLN in the lung. Either 0.75 g/kg of GLN or saline placebo (SP) was administered to male rats 1 h after cecal ligation and puncture (CLP). NF-kappaB activation, IKBalpha degradation, phosphorylation of p38
MAPK
, ERK, and MKP-1 expression were evaluated in lung tissue 6 h post-CLP. Lung tissue iNOS and eNOS, TNF-alpha, IL-6, and IL-18 cytokines were assayed. Last, lung histopathology for occurrence of ARDS and survival were examined. GLN given 1 h postsepsis led to inhibition of lung tissue NF-kappaB activation (P < 0.001 vs. SP), attenuated degradation of IKBalpha, and inhibited phosphorylation of p38
MAPK
, and ERK, pathways critical for cytokine release. GLN treatment increased MKP-1 peptide expression and significantly attenuated TNF-alpha and IL-6 6 h after CLP. IL-18 was attenuated by GLN at multiple time points post-CLP. Further, GLN abrogated increases in lung iNOS expression and enhanced lung eNOS postsepsis. Finally, GLN prevented the histopathologic appearance of ARDS after
sepsis
and significantly improved survival. These data reveal that GLN exerts an antiinflammatory effect in
sepsis
that may be mediated via attenuation of multiple pathways of inflammation such as NF-kappaB, p38
MAPK
, ERK, and MKP-1. GLN also showed an inhibition of increases in iNOS expression. The antiinflammatory effect of GLN was associated with attenuation of ARDS and mortality.
...
PMID:GLUTAMINE PREVENTS ACTIVATION OF NF-kappaB AND STRESS KINASE PATHWAYS, ATTENUATES INFLAMMATORY CYTOKINE RELEASE, AND PREVENTS ACUTE RESPIRATORY DISTRESS SYNDROME (ARDS) FOLLOWING SEPSIS. 1631 91
Group B streptococcus (GBS) is the major cause of
sepsis
in newborn infants. In vitro, inactivated GBS stimulates macrophages to produce inflammatory proteins via the TLR adapter protein MyD88. Furthermore, inflammatory cytokine release in response to GBS greatly exceeds that following stimulation with pneumococci. In this study, we attempted to unravel signaling events that are involved in GBS-, but not Streptococcus pneumoniae-stimulated phagocytes to identify molecular targets for adjunctive
sepsis
therapy. We found that inactivated GBS and S. pneumoniae differed in the activation of the
MAPK
JNK
, but not IkappaB kinase. Furthermore,
JNK
was essential for the transcriptional activation of inflammatory cytokine genes in response to GBS. Inhibition of
JNK
by the anthrapyrazolone SP600125 abrogated GBS-induced cytokine formation via an AP-1- and NF-kappaB-dependent mechanism without impairing antibacterial properties such as phagocytosis of GBS and the formation of intracellular oxidative species. In contrast, inhibition of the
MAPK
p38 impaired both antibacterial processes. In a neonatal mouse model of GBS
sepsis
SP600125 inhibited the inflammatory response and improved survival. In conclusion,
JNK
plays a major role in the inflammatory, but not in the direct antibacterial response to inactivated GBS, and may thus serve as a rational target for an adjunctive GBS
sepsis
therapy.
...
PMID:c-Jun kinase is a critical signaling molecule in a neonatal model of group B streptococcal sepsis. 1649 78
Since the identification of the p38 mitogen-activated protein kinase (
MAPK
) as a key signal-transducing molecule in the expression of the proinflammatory cytokine tumor necrosis factor (TNF) more than 10 years ago, huge efforts have been made to develop inhibitors of p38
MAPK
with the intent to modulate unwanted TNF activity in diseases such as autoimmune diseases or
sepsis
. However, despite some anti-inflammatory effects in animal models, no p38
MAPK
inhibitor has yet demonstrated clinical efficacy in human autoimmune disorders. One possible reason for this paradox might relate to the fact that the p38
MAPK
signaling cascade is involved in the functional regulation of several different cell types that all contribute to the complex pathogenesis of human autoimmune diseases. In particular, p38
MAPK
has a multifaceted role in CD4 T cells that have been implicated in initiating and driving sustained inflammation in autoimmune diseases, such as rheumatoid arthritis or systemic vasculitis. Here we review recent advances in the understanding of the role of the p38
MAPK
signaling cascade in CD4 T cells and the consequences that its inhibition provokes in T cell functions in vitro and in vivo. These new data suggest that p38
MAPK
inhibitors may elicit several unwanted effects in human autoimmune diseases but may be useful for the treatment of allergic disorders.
...
PMID:The p38 mitogen-activated protein kinase signaling cascade in CD4 T cells. 1654 79
Artemisia vestita Wall., a traditional Tibetan medicine, has wide clinical application for inflammatory diseases. However, its molecular mechanism of anti-inflammatory effect is poorly understood. In the present study, we investigated the anti-inflammatory activity and underlying mechanism of the ethanol extract from Artemisia vestita (AV-ext) on lipopolysaccharide (LPS)-induced
sepsis
. Pretreatment with AV-ext significantly decreased the levels of tumor necrosis factor-alpha (TNF-alpha) in serum and liver and lung tissues, and improved the survival of mice with experimental
sepsis
. AV-ext also remarkably reduced the expression levels of TNF-alpha, interleukin-1beta and cyclooxygenase-2 in LPS-stimulated RAW 264.7 macrophages and dose dependently suppressed the activation of mitogen-activated protein kinases (MAPKs), such as p38,
extracellular signal-regulated kinase
(
ERK1
/2) and c-Jun NH2-terminal kinase (JNK). Furthermore, pretreatment with AV-ext dose dependently inhibited the activation of nuclear factor-kappaB (NF-kappaB), as well as the degradation and phosphorylation of inhibitory kappaB (IkappaB) in LPS-activated RAW 264.7 macrophages. These results collectively reveal that AV-ext inhibits TNF-alpha release from macrophages by suppressing
MAPK
and NF-kappaB signaling pathways and suggest that AV-ext may be beneficial for the treatment of endotoxin shock or
sepsis
.
...
PMID:Ethanol extract from Artemisia vestita, a traditional Tibetan medicine, exerts anti-sepsis action through down-regulating the MAPK and NF-kappaB pathways. 1659 87
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