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)

Tumor necrosis factor-alpha (TNF-alpha) plays a role in several disease states such as sepsis, cachexia, and non-insulin-dependent diabetes. TNF-alpha interferes with insulin signaling and inhibits differentiation-specific gene expression in adipose tissue and skeletal muscle. We have examined the mechanisms by which TNF-alpha, in comparison to basic fibroblast growth factor (bFGF), inhibits the insulin-like growth factor-I (IGF-I)-induced differentiation of C2C12 myoblasts. Adhesion of quiescent, suspended myoblasts to collagen in high concentrations of IGF-I (10 nM) induced these cells to proliferate during the initial 24 h postplating and in so doing transiently inhibited the expression of myogenin, an essential transcription factor controlling myoblast differentiation. Low doses of IGF-I (1 nM) were minimally mitogenic and enhanced muscle-specific gene expression. Quiescent myoblasts treated with bFGF in combination with IGF-I did not express myogenin, but expressed proliferating cell nuclear antigen and underwent DNA synthesis. In contrast, TNF-alpha in the presence or absence of 1 nM IGF-I, did not stimulate DNA synthesis in myoblasts. However, TNF-alpha inhibited myogenin mRNA and protein expression. Expression of the cyclin-dependent kinase inhibitor p21 correlated with myogenin expression and myoblast differentiation, but not with growth arrest. These results indicate that both TNF-alpha and bFGF inhibit myogenin expression but differentially influence myoblast proliferation.
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PMID:Tumor necrosis factor-alpha and basic fibroblast growth factor differentially inhibit the insulin-like growth factor-I induced expression of myogenin in C2C12 myoblasts. 1032 64

During the last years many investigations have shown that a major catalyst within the mechanism of skeletal muscle wasting occurring under conditions like sepsis, injuries, trauma, cancer cachexia, chronic acidosis, fasting, glucocorticoid treatment, and insulinopenia is the ubiquitin-proteasome system. Evidence for this was obtained by findings that the rate of ATP-dependent protein degradation is increased, that m-RNA concentrations of several proteasome subunits and ubiquitin are increased and the amount of ubiquitin-protein conjugates is elevated under these conditions. Additionally, the enhanced protein breakdown was shown to be suppressed by proteasome inhibitors. In the present report we show that most but not all of the proteolytic activities of partially purified 20S/26S proteasomes from skeletal muscle of rats increase after induction of Diabetes mellitus. This finding suggests that part of the mechanism of acceleration of muscle protein breakdown is due to changes in proteasome activities.
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PMID:Alterations of proteasome activities in skeletal muscle tissue of diabetic rats. 1036 52

The development of pharmacological approaches for preventing the loss of muscle proteins would be extremely valuable for cachectic patients. For example, severe wasting in cancer patients correlates with a reduced efficacy of chemotherapy and radiotherapy. Pentoxifylline (PTX) is a very inexpensive xanthine derivative, which is widely used in humans as a haemorheological agent, and inhibits tumor necrosis factor transcription. We have shown here that a daily administration of PTX prevents muscle atrophy and suppresses increased protein breakdown in Yoshida sarcoma-bearing rats by inhibiting the activation of a nonlysosomal, Ca(2+)-independent proteolytic pathway. PTX blocked the ubiquitin pathway, apparently by suppressing the enhanced expression of ubiquitin, the 14-kDa ubiquitin conjugating enzyme E2, and the C2 20S proteasome subunit in muscle from cancer rats. The 19S complex and 11S regulator associate with the 20S proteasome and regulate its peptidase activities. The mRNA levels for the ATPase subunit MSS1 of the 19S complex increased in cancer cachexia, in contrast with mRNAs of other regulatory subunits. This adaptation was suppressed by PTX, suggesting that the drug inhibited the activation of the 26S proteasome. This is the first demonstration of a pharmacological manipulation of the ubiquitin-proteasome pathway in cachexia with a drug which is well tolerated in humans. Overall, the data suggest that PTX can prevent muscle wasting in situations where tumor necrosis factor production rises, including cancer, sepsis, AIDS and trauma.
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PMID:Manipulation of the ubiquitin-proteasome pathway in cachexia: pentoxifylline suppresses the activation of 20S and 26S proteasomes in muscles from tumor-bearing rats. 1036 54

Leptin, the ob gene product, has been proposed as a mediator of inflammatory cytokine-dependent decreased food intake and cachexia in rodents. In humans, leptin serum levels increase after administration of tumor necrosis factor-alpha (TNF-alpha) or interleukin-2 or during septicemia. However, the effect of human chronic inflammatory disease on serum leptin is unknown. We therefore determined the serum leptin level (radioimmunoassay), body mass index (BMI), percent body fat ([%BF] bioelectrical impedance analysis), and disease activity (Disease Activity Score [DAS]) in 58 patients with rheumatoid arthritis (RA) and 16 controls. The BMI, %BF, serum leptin, and ratio of leptin to %BF (leptin/%BF) did not differ significantly in 25 patients with moderate RA activity (DAS, 3.6 +/- 0.5), 33 patients with low RA activity (DAS, 1.8 +/- 0.5), and controls. A positive correlation for serum leptin and %BF was detected in all groups. Our data indicate that in RA, a human chronic cytokine-mediated inflammatory disease, the serum leptin level is directly related to %BF but not to disease activity.
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PMID:Leptin serum levels are not correlated with disease activity in patients with rheumatoid arthritis. 1038 Nov 49

Insulin deficiency (e.g., in acute diabetes or fasting) is associated with enhanced protein breakdown in skeletal muscle leading to muscle wasting. Because recent studies have suggested that this increased proteolysis is due to activation of the ubiquitin-proteasome (Ub-proteasome) pathway, we investigated whether diabetes is associated with an increased rate of Ub conjugation to muscle protein. Muscle extracts from streptozotocin-induced insulin-deficient rats contained greater amounts of Ub-conjugated proteins than extracts from control animals and also 40-50% greater rates of conjugation of (125)I-Ub to endogenous muscle proteins. This enhanced Ub-conjugation occurred mainly through the N-end rule pathway that involves E2(14k) and E3alpha. A specific substrate of this pathway, alpha-lactalbumin, was ubiquitinated faster in the diabetic extracts, and a dominant negative form of E2(14k) inhibited this increase in ubiquitination rates. Both E2(14k) and E3alpha were shown to be rate-limiting for Ub conjugation because adding small amounts of either to extracts stimulated Ub conjugation. Furthermore, mRNA for E2(14k) and E3alpha (but not E1) were elevated 2-fold in muscles from diabetic rats, although no significant increase in E2(14k) and E3alpha content could be detected by immunoblot or activity assays. The simplest interpretation of these results is that small increases in both E2(14k) and E3alpha in muscles of insulin-deficient animals together accelerate Ub conjugation and protein degradation by the N-end rule pathway, the same pathway activated in cancer cachexia, sepsis, and hyperthyroidism.
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PMID:Ubiquitin conjugation by the N-end rule pathway and mRNAs for its components increase in muscles of diabetic rats. 1056 3

Muscle protein breakdown during sepsis is associated with upregulated expression and activity of the ubiquitin-proteasome proteolytic pathway. Previous studies suggest that ubiquitination of proteins in skeletal muscle is regulated by the ubiquitin ligase E3alpha together with the 14 kDa ubiquitin-conjugating enzyme E2(14k). The E3alpha gene was cloned only recently. The influence of sepsis on the gene expression of E3alpha in skeletal muscle has not been reported. In the present study, induction of sepsis in rats by cecal ligation and puncture resulted in increased mRNA levels for E3alpha in white, fast-twitch but not in red slow-twitch muscle. Treatment with the glucocorticoid receptor antagonist RU38486 (10 mg/kg) prevented the sepsis-induced increase in E3alpha and E2(14k) mRNA levels. The present study is the first report of increased E3alpha expression in skeletal muscle during sepsis. The results lend further support to the concept that glucocorticoid-mediated upregulation of the ubiquitin-proteasome proteolytic pathway is involved in sepsis-induced muscle cachexia. Increased expression of both E3alpha and E2(14k) suggests that muscle proteins are degraded in the N-end rule pathway during sepsis.
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PMID:The gene expression of ubiquitin ligase E3alpha is upregulated in skeletal muscle during sepsis in rats-potential role of glucocorticoids. 1063 Oct 91

An overproduction of proinflammatory cytokines mediates the damaging sequelae of inflammation in pathologic conditions such as rheumatoid arthritis, graft-vs-host reaction, cachexia, and sepsis syndrome. We examined the cytokine regulatory activity of synthetic melanin, exemplified by biosynthetic l-glycine-l-tyrosine-based polymer (ME-1) and chemosynthetic dihydroxyphenylalanine-based polymer (MC-1). At nontoxic concentrations, both compounds effectively (>/=60%) and reversibly suppressed the production of tumor necrosis factor (TNF), even when applied after stimulation of human peripheral blood monocytes with lipopolysaccharide (LPS). The inhibitory activity of melanin was selective with regard to cytokine response but not inducer- or cell-type-specific. In addition to TNF, melanin inhibited production of interleukin (IL)-1beta, IL-6, and IL-10 but not granulocyte-macrophage colony-stimulating factor by the LPS-stimulated monocytes. Melanin was equally effective in inhibiting production of TNF by monocytes stimulated with the purified protein derivative of Mycobacterium tuberculosis and production of IL-6 by IL-1alpha-stimulated human fibroblasts and endothelial cells. Northern blot analysis, mRNA stability determination, immunoprecipitation studies on metabolically labeled intracellular TNF, and pulse chase experiments revealed that melanin reduced efficiency of mRNA translation. The finding that melanin arrests ongoing cytokine synthesis suggests that this compound may be useful as an adjunct therapy for conditions showing involvement of proinflammatory cytokines.
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PMID:Synthetic melanin suppresses production of proinflammatory cytokines. 1067 72

C3H/HeJ mice have an impaired ability to respond to lipopolysaccharide (LPS) due to a mutation in the gene that encodes Toll-like receptor 4 (TLR4). The effect of TLR4 deficiency on host responses to endodontic infections is unknown. In the present study, we compared periapical bone destruction, sepsis, and inflammatory cytokine production in LPS-hyporesponsive C3H/HeJ and wild-type control C3H/HeOuJ mice. The mandibular first molars of both strains were subjected to pulpal exposure and infection with a mixture of four anaerobic pathogens, Prevotella intermedia, Fusobacterium nucleatum, Streptococcus intermedius, and Peptostreptococcus micros. At sacrifice on day 21, TLR4-deficient C3H/HeJ mice had significantly reduced periapical bone destruction compared to wild-type C3H/HeOuJ mice (P < 0.001). The decreased bone destruction in C3H/HeJ correlated with reduced expression of the bone resorptive cytokines interleukin 1alpha (IL-1alpha) (P < 0.01) and IL-1beta (P < 0.05) as well as the proinflammatory cytokine IL-12 (P < 0.05). No significant differences were seen in the levels of gamma interferon, tumor necrosis factor alpha (TNF-alpha), or IL-10 between the two strains. The expression of IL-1alpha, IL-1beta, TNF-alpha, IL-10, and IL-12 were all significantly reduced in vitro in macrophages from both TLR4-deficient C3H/HeJ and C57BL/10ScNCr strains, compared to wild-type controls. Notably, the responses of TLR4-deficient macrophages to both gram-positive and gram-negative bacteria were similarly reduced. Neither C3H/HeJ nor C3H/HeOuJ mice exhibited orofacial abscess development or infection dissemination as determined by splenomegaly or cachexia. We conclude that intact TLR function mediates increased proinflammatory responses and bone destruction in response to mixed anaerobic infections.
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PMID:Toll-like receptor 4-deficient mice have reduced bone destruction following mixed anaerobic infection. 1089 73

We examined the effect of insulin-like growth factor I (IGF-I), administered in vivo, on protein turnover rates and gene expression of the ubiquitin-proteasome proteolytic pathway in skeletal muscle of septic rats. Sepsis was induced by cecal ligation and puncture. Other rats were sham-operated. Miniosmotic pumps were implanted sc, and groups of rats received IGF-I (7 mg/kg x 24 h) or saline. Protein synthesis and breakdown rates were determined in incubated extensor digitorum longus muscles. Messenger RNA levels for ubiquitin and the ubiquitin-conjugating enzyme E2(14k) were determined by Northern blot analysis. Sepsis resulted in an approximately 30% reduction of muscle protein synthesis, and this effect of sepsis was blunted in rats treated with IGF-I. In contrast, IGF-I did not prevent the sepsis-induced increase in total and myofibrillar muscle protein breakdown. Ubiquitin and E2(14k) messenger RNA levels were increased several fold in muscle from septic rats, and this effect of sepsis was abolished in IGF-I treated rats. The results suggest that administration of IGF-I may improve sepsis-induced muscle cachexia by stimulating protein synthesis. However, because muscles were resistant to IGF-I, with regard to regulation of protein breakdown, the use of IGF-I to treat muscle cachexia during sepsis remains unclear. An additional important implication of the present study is that changes in messenger RNA levels for ubiquitin and the ubiquitin-conjugating enzyme E2(14k) do not always reflect changes in muscle protein breakdown rates.
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PMID:Insulin-like growth factor I reduces ubiquitin and ubiquitin-conjugating enzyme gene expression but does not inhibit muscle proteolysis in septic rats. 1091 58

This year, the US Institute of Medicine has estimated that medical errors kill up to 98,000 Americans each year,1 a problem surpassing automobile fatalities. For patients on the medical ward, drug therapy is the primary intervention they are receiving yet medication errors occur in as many as 4% of inpatients.2 Although greater monitoring intensity and much lower nurse-patient ratios in the ICU may reduce the incidence of medication errors, the shear number if interventions dramatically increases the risk of error.3 Furthermore, the study by the Institute of Medicine only addressed a small part of the problem. The taxonomy of errors includes both "accidents" (skill-based errors) and intentional "mistakes" (knowledge-based and rule-based errors).2 Thus, the Institute of Medicine would not consider the proscribing of human growth hormone for cachexia an error unless the proscribed dose was not administered or it was given to the wrong patient. In the ICU, the risks associated with both kinds of errors are considerable. In this review we will focus on the second kind of errors and examine harms associated with the care of patients with sepsis.
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PMID:Limiting harm in the ICU. 1096 10


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