Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0243026 (sepsis)
 52,417 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the past decade it has become apparent that many diseases result from aberrations in signaling pathways. These include proliferative diseases such as cancers, atherosclerosis and psoriasis and inflammatory conditions such as sepsis, rheumatoid arthritis and tissue rejection. These findings refocused the research of the medical community to seek new modalities for disease management which essentially consist of designing drugs which intercept cell signaling. In this review, the emerging success in using tyrosine kinase blockers and other signal interceptors, such as protein kinase C blockers, Ras blockers, Ca2+ signaling inhibitors and estrogen antagonists which inhibit growth of cancer cells in vitro and in vivo, will be discussed. These signal interceptors, especially tyrosine-kinase blockers, are also able to block inflammatory responses and the proliferation of vascular smooth muscle cells and psoriatic keratinocytes. The utility of signal interceptors in analyzing signal-transduction pathways is also discussed.
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PMID:Signal-transduction therapy. A novel approach to disease management. 795 36

It is believed that induction of cytokine expression by bacterial cell wall components plays a role in the development and course of sepsis. However, most attention has been focused on lipopolysaccharide (LPS). We studied the ability of N-acetylglucosaminyl-1,6-anhydro-N-acetylmuramyl-L-alanyl-D- isoglutamyl-m-diaminopimelyl-D-alanine (G(Anh)MTetra), a naturally occurring breakdown product of peptidoglycan that is produced by soluble lytic transglycosylase of Escherichia coli, to induce cytokine expression in human monocytes. G(Anh)MTetra was found to strongly induce interleukin (IL)-1 beta and IL-6 mRNA expression after 2 h and IL-1 beta and IL-6 protein secretion after 48 h of activation. The increase in mRNA accumulation was at least partly due to an increase in the transcription rates of the respective genes and was accompanied by a strong induction of nuclear factor-kappa B and activator protein-1 transcription factor expression. Experiments using inhibitors of protein kinase C, protein kinase A, and tyrosine kinase-dependent pathways revealed that G(Anh)MTetra-induced IL-1 beta and IL-6 mRNA expression involves activation of an H7-inhibitable pathway. By using the protein synthesis inhibitor cycloheximide, it was shown that G(Anh)MTetra-induced IL-6 mRNA expression depends on the synthesis of new protein, whereas G(Anh)MTetra-induced IL-1 beta mRNA accumulation does not. When responses to G(Anh)MTetra were compared with those to LPS and muramyldipeptide (MDP), it was found that the optimal response to G(Anh)MTetra induction was similar to that of LPS but significantly higher than the response to MDP. Furthermore, maximal G(Anh)MTetra-induced IL-1 beta and IL-6 mRNA expression could be enhanced by co-stimulation with LPS or MDP, suggesting that different receptors and/or transduction pathways were involved. These results indicate that G(Anh)MTetra induces IL-1 beta and IL-6 expression in human monocytes suggesting a possible role for G(Anh)MTetra in the release of cytokines during sepsis.
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PMID:G(Anh)MTetra, a natural bacterial cell wall breakdown product, induces interleukin-1 beta and interleukin-6 expression in human monocytes. A study of the molecular mechanisms involved in inflammatory cytokine expression. 830 82

Many different cellular processes are altered by microenvironmental changes in the oxygen level, particularly hypoxia. In most cases, these hypoxic effects are mediated via alterations in cellular signal transduction pathways. Low oxygen states are generally viewed as deleterious; however, recent studies show that alterations in oxygen levels are physiologically important, influencing cells in a variety of ways. Low oxygen levels can stimulate cellular processes, such as the production of tumor necrosis factor, interleukin (IL)-1, IL-8, and nuclear factor kappa B. Kupffer cell-mediated alterations in cocultured hepatocyte function are altered by pre-exposure to hypoxic culture conditions, whereas superoxide production, intracellular pH, and adenosine triphosphate levels are decreased by hypoxia. Hypoxia followed by reoxygenation stimulates tyrosine kinase enzymes and increases intracellular calcium in a variety of cells. This review highlights recent findings concerning the manner and mechanisms by which low oxygen levels influence cell functions and cellular signaling systems. Detailed information is still lacking about the location and mechanism of most hypoxic-mediated alterations in cell signaling pathways. However, information about how factors altered by trauma and sepsis, such as Po2, acidosis, and endotoxin, effect cellular signaling pathways is rapidly emerging. Understanding the mechanism by which oxygen availability alters cell function will be important to the development of optimal therapies for post-traumatic shock and organ dysfunction.
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PMID:Hypoxic alterations in cellular signal transduction in shock and sepsis. 877 93

X-linked agammaglobulinemia (XLA) is usually considered a disorder of B cell development; however, the gene that is defective in XLA encodes a cytoplasmic tyrosine kinase called Btk, that is expressed throughout myeloid as well as B cell differentiation. A review of medical records of patients in whom mutations in Btk had been identified indicated that 13 of 50 patients (26%) had experienced episodes of profound neutropenia. In 12 of the 13 patients, neutropenia was part of the acute illness that precipitated an evaluation for immunodeficiency. These boys were more likely to be less than a year of age at the time of diagnosis and they were less likely to have a family history of immunodeficiency. Neutropenia was associated with staphylococcal or pseudomonas sepsis in 6 of the patients. The duration of neutropenia was variable but was often more than 1 week. Neutropenia was not seen in any patient with XLA receiving intravenous gammaglobulin. Although neutropenia was not associated with any specific mutation in Btk, most of the alterations in this gene in the patients with XLA and neutropenia resulted in the absence of Btk protein or in amino acid substitutions in sites thought to be critical to Btk function. Btk may not be required for neutrophil production under normal circumstances; however, it may play a role in the response to stress.
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PMID:Neutropenia in X-linked agammaglobulinemia. 893 4

Alterations in protein kinase C (PKC) activity have been implied in the pathogenesis of common variable immunodeficiency (CVID). We analyzed amiloride-sensitive red blood cell Na+/H+ exchange (sodium-proton antiport, SPA) and its response to protein kinase stimulation in a patient with CVID. Compared with healthy subjects or patients with sepsis, a unique pattern of SPA activation has been shown. The patient's SPA was decreased and unresponsive to PKC stimulation, whereas stimulation by insulin, a tyrosine kinase activator, restored SPA activity. An alteration of serine-threonine phosphorylation is suggested as a possible mechanism for the immune failure.
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PMID:Common variable immunodeficiency associated with myelocathexis and altered membrane sodium-proton antiport. 920 Jan 89

A critical feature of sepsis-induced adult respiratory distress syndrome (ARDS) is the release of cytokines (such as interleukin [IL]-6, IL-8, and tumor necrosis factor [TNF]) from endotoxin (lipopolysaccharide [LPS])-activated alveolar macrophages (AM). Nuclear factor kappa B (NF-kappaB) is activated in AM from patients with ARDS, and it is essential for the transcription of many cytokine genes. In these studies, we evaluated the regulation of LPS-induced cytokine release and the activation of NF-kappaB in human AM. We found that the activation of NF-kappaB and the release of IL-6, IL-8, and TNF from AM exposed to LPS was protein kinase C-independent and tyrosine kinase- and phosphatidylcholine-specific phospholipase C-dependent. We also found that LPS-induced activation of NF-kappaB was enhanced in AM cultured in serum or in the presence of LPS-binding protein, simulating conditions in the lung that are present in ARDS. In addition, LPS triggered the activation of several different NF-kappaB complexes in AM, and different forms of NF-kappaB bound to the IL-6, IL-8, and TNF promoter sequences. These observations suggest that physiologic abnormalities present in the lungs of patients with ARDS facilitate the activation of NF-kappaB and local release of cytokines.
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PMID:Lipopolysaccharide-induced NF-kappaB activation and cytokine release in human alveolar macrophages is PKC-independent and TK- and PC-PLC-dependent. 949 Jun 56

LPS endotoxin-induced macrophage activation is recognized to be important in both nonspecific immunity and endotoxin-induced sepsis when excessive macrophage stimulation occurs. In this study, we showed that reduction of c-Abl in macrophages prevented LPS-induced growth arrest, nitric oxide production and TNF-alpha secretion by ANA-1 macrophages. These cells continued to grow but later underwent apoptosis. Reduction of c-Abl in these cells led to reduced c-Abl kinase activity associated with Ran, which recently has been shown to be an LPS-responsive gene product. Our data suggest that c-Abl tyrosine kinase is one of the intermediates downstream of the initial signal transduction event related to activation of macrophages by LPS.
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PMID:Involvement of C-Abl tyrosine kinase in lipopolysaccharide-induced macrophage activation. 953 Dec 91

The regulation of monocyte function and the inhibition of TNF-alpha production during bacterial sepsis are critical in attenuating adverse host responses to endotoxemia. To study the function of a novel receptor tyrosine kinase, mer, that is expressed in monocytes, we generated mice (merkd) that lack the signaling tyrosine kinase domain. Upon LPS challenge, merkd animals died of endotoxic shock (15/17, 88.2%), whereas control wild-type mice survived (1/15, 6.7% died). Susceptible merkd mice exhibited edema, leukocyte infiltration, and signs of endotoxic shock that correlated with higher levels of TNF-alpha found in the serum of merkd mice as compared with wild-type control animals. Death due to LPS-induced endotoxic shock in merkd mice was blocked by administration of anti-TNF-alpha Ab, suggesting that overproduction of this cytokine was principally responsible for the heightened suseptibility. The increase in TNF-alpha production appeared to be the result of a substantial increase in the LPS-dependent activation of NF-kappa B nuclear translocation resulting in greater TNF-alpha production by macrophages from merkd mice. Thus, Mer receptor tyrosine kinase signaling participates in a novel inhibitory pathway in macrophages important for regulating TNF-alpha secretion and attenuating endotoxic shock.
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PMID:A novel receptor tyrosine kinase, Mer, inhibits TNF-alpha production and lipopolysaccharide-induced endotoxic shock. 1009 6

Kupffer cells, a majority of the body's fixed macrophages, are a major site of bacterial lipopolysaccharide (LPS) metabolism and are mediators in the body's response to sepsis. Uptake of LPS is different in Kupffer cells than other macrophages. Signal transduction in other macrophages in response to LPS involves phosphorylation of proteins in the 50-60 kDa range. We hypothesized that Kupffer cells may have unique signal transduction pathways in response to LPS. Rat Kupffer cells were exposed to LPS (1 microgram/mL) for varying times ranging from 15 to 90 min. Cell lysates were Western blotted using an anti-phosphotyrosine antibody. The blots showed an increase in the amount of tyrosine phosphorylation on two proteins of 119 kDa and 83 kDa. The effects of varying LPS concentration (1 ng/mL-1 microgram/mL) showed an increasing amount of phosphorylation with increasing LPS concentration. To associate the importance of tyrosine phosphorylation in the response of Kupffer cells to LPS, the tyrosine kinase inhibitors, tyrphostin, lavendustin, and genisten were used to study the effects of inhibiting phosphorylation on TNF-alpha production. Kupffer cells were preincubated in the presence of the inhibitor and exposed to LPS (1 microgram/mL). TNF-alpha was measured in the conditioned media by ELISA. A 70% or greater decrease in TNF-alpha production was observed. When phagocytosis of latex beads by rat Kupffer cells was measured in vivo using intravital video microscopy, LPS treatment significantly increased uptake. This increase in phagocytosis was inhibited by tyrphostin. These results show what may be unique phosphorylation events in Kupffer cells that are related to LPS induced production of TNF-alpha.
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PMID:Tyrosine kinase activation in LPS stimulated rat Kupffer cells. 1035 46

Tyrosine phosphorylation pathways are essential components of the process of macrophage activation and the resultant production of inflammatory mediators such as tumor necrosis factor (TNF) and nitric oxide (NO). Several lines of evidence suggest that members of the src family of protein tyrosine kinases play important roles in macrophage activation by gram-negative bacterial lipopolysaccharide (LPS) or the cytokine interferon-gamma (IFN-gamma), but targeted disruption of three members of the src family (hck, fgr, and lyn) in mice failed to demonstrate a requirement for these particular kinases in macrophage activation. We report that the pyrazolopyrimidine PP1, a src family-selective tyrosine kinase inhibitor, potently inhibits the production of TNF and inducible nitric oxide synthase (iNOS) in RAW 264.7 murine macrophages stimulated with LPS, rlFN-gamma, or LPS + rIFN-gamma. Furthermore, the tested concentrations of PP1 inhibit LPS- and rlFN-gamma-mediated tyrosine phosphorylation of the hck tyrosine kinase and its putative substrate, vav, but fail to block rlFN-gamma-mediated JAK2 tyrosine phosphorylation. These findings provide additional support for a model of macrophage activation involving one or more src-related kinases. Selective inhibitors of this signaling pathway should be studied in animal models of sepsis.
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PMID:The src family-selective tyrosine kinase inhibitor PP1 blocks LPS and IFN-gamma-mediated TNF and iNOS production in murine macrophages. 1056 9


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