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)

With trauma, sepsis, cancer, or uremia, animals or patients experience accelerated degradation of muscle protein in the ATP-ubiquitin-proteasome (Ub-P'some) system. The initial step in myofibrillar proteolysis is unknown because this proteolytic system does not break down actomyosin complexes or myofibrils, even though it degrades monomeric actin or myosin. Since cytokines or insulin resistance are common in catabolic states and will activate caspases, we examined whether caspase-3 would break down actomyosin. We found that recombinant caspase-3 cleaves actomyosin, producing a characteristic, approximately 14-kDa actin fragment and other proteins that are degraded by the Ub-P'some. In fact, limited actomyosin cleavage by caspase-3 yields a 125% increase in protein degradation by the Ub-P'some system. Serum deprivation of L6 muscle cells stimulates actin cleavage and proteolysis; insulin blocks these responses by a mechanism requiring PI3K. Cleaved actin fragments are present in muscles of rats with muscle atrophy from diabetes or chronic uremia. Accumulation of actin fragments and the rate of proteolysis in muscle stimulated by diabetes are suppressed by a caspase-3 inhibitor. Thus, in catabolic conditions, an initial step resulting in loss of muscle protein is activation of caspase-3, yielding proteins that are degraded by the Ub-P'some system. Therapeutic strategies could be designed to prevent these events.
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PMID:Activation of caspase-3 is an initial step triggering accelerated muscle proteolysis in catabolic conditions. 1470 15

Mitochondria are the specialized organelles for energy metabolism but also participate in the production of O(2) active species, cell cycle regulation, apoptosis and thermogenesis. Classically, regulation of mitochondrial energy functions was based on the ADP/ATP ratio, which dynamically stimulates the transition between resting and maximal O(2) uptake. However, in the last years, NO was identified as a physiologic regulator of electron transfer and ATP synthesis by inhibiting cytochrome oxidase. Additionally, NO stimulates the mitochondrial production of O(2) active species, primarily O(2)(-) and H(2)O(2), and, depending on NO matrix concentration, of ONOO(-), which is responsible for the nitrosylation and nitration of mitochondrial components. By this means, alteration in mitochondrial complexes restricts energy output, further increases O(2) active species and changes cell signaling for proliferation and apoptosis through redox effects on specific pathways. These mechanisms are prototypically operating in prevalent generalized diseases like sepsis with multiorgan failure or limited neurodegenerative disorders like Parkinson's disease. Complex I appears to be highly susceptible to ONOO(-) effects and nitration, which defines an acquired group of mitochondrial disorders, in addition to the genetically induced syndromes. Increase of mitochondrial NO may follow over-expression of nNOS, induction and translocation of iNOS, and activation and/or increased content of the newly described mtNOS. Likewise, mtNOS is important in the modulation of O(2) uptake and cell signaling, and in mitochondrial pathology, including the effects of aging, dystrophin deficiency, hypoxia, inflammation and cancer.
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PMID:Nitric oxide, complex I, and the modulation of mitochondrial reactive species in biology and disease. 1505 22

The intranuclear architectural protein that is termed high mobility group box chromosomal protein 1 (HMGB1) was recently identified as a potent proinflammatory mediator when present extracellularly. HMGB1 has been demonstrated to be a long-searched-for nuclear danger signal passively released by necrotic, as opposed to apoptotic, cells that will induce inflammation. Furthermore, HMGB1 can also be actively secreted by stimulated macrophages or monocytes in a process requiring acetylation of the molecule, which enables translocation from the nucleus to secretory lysosomes. Subsequent transport out of the cells depends on a secretion signal mediated by either extracellular lysophophatidyl-choline or ATP. HMGB1 passively released from necrotic cells and HMGB1 actively secreted by inflammatory cells are thus molecularly different. Extracellular HMGB1 acts as a cytokine by signaling via the receptor for advanced glycated end-products and via members of the Toll-like receptor family. The initiated inflammatory responses include the production of multiple cytokines, chemoattraction of certain stem cells, induction of vascular adhesion molecules and impaired function of intestinal epithelial cells. Therapeutic administration of HMGB1 antagonists rescues mice from lethal sepsis, even when initial treatment is delayed for 24 h after the onset of infection, establishing a clinically relevant therapeutic window that is significantly wider than for other known cytokines.
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PMID:Mini-review: The nuclear protein HMGB1 as a proinflammatory mediator. 1516 19

In late sepsis, it has been established that the liver plays a major role in the initiation of multiorgan failure, which is the most lethal complication in hospitals. The molecular mechanism underlying liver failure that results from sepsis remains elusive. This study was undertaken to identify the bona fide differentially expressed genes in the 18-h septic liver by suppression subtractive hybridization, and the data were corroborated by Northern blot analysis. The differential gene expression profile renders a clue as to the genes involved in septic liver failure. The cecal ligation and puncture (CLP) model of a polymicrobial septic rat was used, with the late sepsis referring to animals sacrificed at 18 h after CLP. We have identified three upregulated genes (TII-kininogen, serine protease inhibitor 2.2 [Spi2.2], and alpha 2 macroglobulin [alpha M]) and six down-regulated genes (hydroxysteroid dehydrogenase [3 alpha HSD], EST189895/mouse RNase4, bile acid-CoA-amino acid N-acyltransferase [kan-1/rBAT], IF1, albumin, and alpha 2u-globulins [alpha 2u-G PGCL1]). Among these genes, the 3 alpha HSD and kan-1/rBAT are involved in bile acid metabolism. The IF1 plays a crucial role in any disease that involves ATP hydrolysis by F1F0-ATPase. The alpha 2M, TII-kininogen, and Spi2.2 are protease inhibitors. The functions of the alpha 2u-G PGCL1 and EST189895/mouse RNase4 genes are unknown. The present results suggest that the roles of disturbance of bile acid metabolism/synthesis and the abolishment of ATP production may contribute to liver failure during late sepsis.
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PMID:Isolation of bona fide differentially expressed genes in the 18-hour sepsis liver by suppression subtractive hybridization. 1516 84

Melatonin is a natural occurring compound with well-known antioxidant properties. In the last decade a new effect of melatonin on mitochondrial homeostasis has been discovered and, although the exact molecular mechanism for this effect remains unknown, it may explain, at least in part, the protective properties found for the indoleamine in degenerative conditions such as aging as well as Parkinson's disease, Alzheimer's disease, epilepsy, sepsis and other injuries such as ischemia-reperfusion. A common feature in these diseases is the existence of mitochondrial damage due to oxidative stress, which may lead to a decrease in the activities of mitochondrial complexes and ATP production, and, as a consequence, a further increase in free radical generation. A vicious cycle thus results under these conditions of oxidative stress with the final consequence being cell death by necrosis or apoptosis. Melatonin is able of directly scavenging a variety of toxic oxygen and nitrogen-based reactants, stimulates antioxidative enzymes, increases the efficiency of the electron transport chain thereby limiting electron leakage and free radical generation, and promotes ATP synthesis. Via these actions, melatonin preserves the integrity of the mitochondria and helps to maintain cell functions and survival.
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PMID:Melatonin and mitochondrial function. 1518 71

Our results show that melatonin and N-acetyl-5-methoxykynurenamine (aMK) physiologically regulate both the electron transport chain (ETC) and OXPHOS, increasing the electron transport and ATP synthesis by normal mitochondria. Melatonin also counteracts mitochondrial oxidative damage induced by t-butyl hydroperoxide, recovering glutathione levels and ATP production. However, the effects of melatonin not only depend of its antioxidant properties, since the indoleamine specifically interacts with complex I and IV of the ETC increasing their activity. Experiments in vivo showed that melatonin administration prevents sepsis-induced ETC damage decreasing the activity and expression of INOS and mtNOS, thus reducing intramitochondrial nitric oxide (NO) and peroxynitrite (ONOO-) levels. Consequently, mitochondrial ETC ad ATP production recovered to normal conditions. The presence of specific binding of melatonin in mitochondrial matrix led us to explore the genomic role of the indoleamine in these organelles. In vivo and in vitro experiments showed that administration of melatonin increased mtONA transcriptional activity of the subunits 1-3 of the complex IV. These effects correlated well with the effects of melatonin on complex IV activity. The data suggest a new rate for melatonin to regulate mitochondrial homeostasis. Due to the relationships between mitochondrial damage, aging and neurodegenerative diseases, the effects of melatonin here described further support its antiaging and neuroprotective properties.
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PMID:Mitochondrial regulation by melatonin and its metabolites. 1520 73

Sepsis-induced vasodilation is characterized by an attenuated sensitivity to vasoconstrictor substances such as norepinephrine, possibly mediated by activation of vascular potassium channels. We determined whether vasodilation associated with potassium channel activation resulted in an attenuated vasoconstrictive response to norepinephrine in humans and whether the vasodilation associated with potassium channel activation could be inhibited by pharmacological potassium channel blockers. In 30 volunteers, the brachial artery was cannulated for infusion of drugs. Forearm blood flow (FBF) was measured in both arms using strain-gauge venous occlusion plethysmography. Forearm vascular resistance (FVR, mean arterial pressure/FBF) was calculated. The effects of vasodilation induced by sodium nitroprusside (SNP, nitric oxide donor) or diazoxide (activator of the ATP-dependent potassium channel) on norepinephrine-mediated vasoconstriction were examined. Also, the effects of potassium channel blockers on vasodilation associated with potassium channel activation were determined. Intraarterial SNP infusion (2 microg/min/dL) increased forearm blood flow by 235%, from (mean +/- SEM) 2.8 +/- 0.7 to 9.4 +/- 1.5 mL/min/dL (P < 0.0001). Subsequent norepinephrine infusion (10, 30, 100, 300, 1000 ng/min/dL) increased FVR dose-dependently from 13 +/- 4 AU to 249 +/- 45 AU at the highest norepinephrine infusion. Intraarterial diazoxide infusion (1 mg/min/dL) increased FBF by 209% from 2.2 +/- 0.3 to 6.8 +/- 1.0 mL/min/dL (P < 0.001). Subsequent norepinephrine infusion increased FVR from 18 +/- 5 to 51 +/- 6 AU at the highest norepinephrine infusion rate (n = 10), significantly different from the norepinephrine-induced effects during SNP coinfusion (P < 0.001). Diazoxide-induced fall in FVR in the infused forearm was inhibited by potassium channel blockers tetraethyl ammonium (1 mg/min/dL, n = 10, P = 0.004) and quinine (50 microg/min/dL, n = 10, P = 0.016). Vasodilation induced by vascular potassium channel activation is associated with an impressive reduction in the vasoconstrictor response to norepinephrine in humans. In accordance with animal experiments, this indicates that potassium channel activation could account for the diminished norepinephrine sensitivity in septic patients. Vasodilation associated with potassium channel activation can be inhibited by pharmacological potassium channel blockade. The possible role of potassium channel blockers during sepsis-induced potassium channel activation and vasodilation in humans needs further elucidation.
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PMID:Activation of the ATP-dependent potassium channel attenuates norepinephrine-induced vasoconstriction in the human forearm. 1537 86

Liver function failure is one of the characteristics of critically ill, septic patients and is associated with worse outcome. Our previous studies have demonstrated that heat-shock response protects cells and tissue from subsequent insults and improves survival during sepsis. In this study, we have shown that mitochondrial cytochrome c oxidase (CCO) is one of the major sources of that protective effect. Experimental sepsis was induced by the cecal ligation and puncture (CLP) method. Heat-shock treatment was induced in rats by hyperthermia 24 h before CLP operation. The results showed that ATP content of the liver declined significantly, and the enzymatic activity of mitochondrial CCO was apparently suppressed during the late stages of sepsis. The mitochondrial ultrastructure of septic liver showed the deformity, mild swelling and inner membrane budding. Heat-shock treatment led to heat-shock protein 72 overexpression and prevented the downregulation of Grp75 during sepsis. On the contrary, the expression of the enzyme complex and its activity were preserved, associated with the minimization of ultrastructural deformities. In conclusion, the maintenance of mitochondrial function, especially the CCO, may be an important strategy in therapeutic interventions of a septic liver.
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PMID:Cytochrome c oxidase as the target of the heat shock protective effect in septic liver. 1537 57

Although protein carbonyl formation is an index of oxidative stress in skeletal muscles, the exact proteins, which undergo oxidation in these muscles, remain unknown. We used 2D electrophoresis, immunoblotting, and mass spectrometry to identify carbonylated proteins in the diaphragm in septic animals. Rats were injected with saline (control) or Escherichia coli lipopolysaccharides (LPS) and killed after various intervals. Diaphragm protein carbonylation increased significantly and peaked 12 h after LPS injection, and it was localized both inside muscle fibers and in blood vessels supplying muscle fibers. Aldolase A, glyceraldehyde 3-phosphate dehydrogenase, enolase 3beta, mitochondrial and cytosolic creatine kinases, alpha-actin, carbonic anyhdrase III, and ubiquinol-cytochrome c reductase were all carbonylated in septic rat diaphragms. In addition, we found significant negative correlations between the intensity of carbonylation and creatine kinase and aldolase activities. We conclude that glycolysis, ATP production, CO2 hydration, and contractile proteins are targeted by oxygen radicals inside the diaphragm during sepsis.
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PMID:Protein carbonyl formation in the diaphragm. 1547 39

Melatonin, or N-acetyl-5-methoxytryptamine, is a compound derived from tryptophan that is found in all organisms from unicells to vertebrates. This indoleamine may act as a protective agent in disease conditions such as Parkinson's, Alzheimer's, aging, sepsis and other disorders including ischemia/reperfusion. In addition, melatonin has been proposed as a drug for the treatment of cancer. These disorders have in common a dysfunction of the apoptotic program. Thus, while defects which reduce apoptotic processes can exaggerate cancer, neurodegenerative disorders and ischemic conditions are made worse by enhanced apoptosis. The mechanism by which melatonin controls cell death is not entirely known. Recently, mitochondria, which are implicated in the intrinsic pathway of apoptosis, have been identified as a target for melatonin actions. It is known that melatonin scavenges oxygen and nitrogen-based reactants generated in mitochondria. This limits the loss of the intramitochondrial glutathione and lowers mitochondrial protein damage, improving electron transport chain (ETC) activity and reducing mtDNA damage. Melatonin also increases the activity of the complex I and complex IV of the ETC, thereby improving mitochondrial respiration and increasing ATP synthesis under normal and stressful conditions. These effects reflect the ability of melatonin to reduce the harmful reduction in the mitochondrial membrane potential that may trigger mitochondrial transition pore (MTP) opening and the apoptotic cascade. In addition, a reported direct action of melatonin in the control of currents through the MTP opens a new perspective in the understanding of the regulation of apoptotic cell death by the indoleamine.
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PMID:Melatonin mitigates mitochondrial malfunction. 1561 31


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