Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Bcl-2 associated athanogene (BAG) family of proteins function as cochaperones by bridging molecules that recruit molecular chaperones to target proteins. BAG-1 provides a physical link between the heat shock proteins Hsc70/Hsp70 and the proteasome to facilitate ubiquitin-proteasome-mediated protein degradation. In addition to the proteasome, protein degradation via autophagy is responsible for maintaining cellular metabolism, organelle homeostasis and redox equilibrium. Our recent report shows that autophagy plays an important role in cardiac adaptation-induced cell survival against ischemia-reperfusion injury in association with the BAG-1 protein. BAG-1 is associated with the autophagosomal membrane protein LC3-II and it may participate in the induction of autophagy via Hsc70. Moreover, another BAG family member, BAG-3, is responsible for the induction of macroautophagy in association with HspB8. These results show the involvement of BAG family members in the induction of autophagy for the degradation of damaged or oxidized proteins to promote cell survival.
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PMID:BAG-1 induces autophagy for cardiac cell survival. 1900 66

Proteasome regulates diverse cellular functions by eliminating ubiquitinated proteins. Protein kinase A (PKA) is a key regulator of proteasome activity. However, it remains unknown how PKA regulates proteasome activity and whether it controls proteasome activity in in vivo hearts. Both the in vitro peptidase assay and the in-gel peptidase assays showed that the treatment with PKA for 30 min dose-dependently activated purified 26S proteasome. Simultaneously, PKA treatment enhanced phosphorylation and assembly of purified 26S proteasome evaluated by non-reducing native polyacrylamide gel electrophoresis, either of which was blunted by the pretreatment with a PKA inhibitor, H-89. In in vivo canine hearts, proteasome assembly and activity were enhanced 30 min after the exogenous or endogenous stimulation of PKA by the intracoronary administration of isoproterenol or forskolin for 30 min or by ischemic preconditioning (IP) with 4 times of repeated 5 min of ischemia. The intracoronary administration of H-89 blunted the enhancement of proteasome assembly and activity by IP. Myocardial proteasome activity at the end of ischemia was decreased compared with the control, however, it did not differ from the control in dogs with IP. IP decreased the accumulation of ubiquitinated proteins in the canine ischemia/reperfusion myocardium, which was blunted by the intracoronary administration of a proteasome inhibitor, epoxomicin. However, proteasome activation by IP was not involved in its infarct size-limiting effects. These findings indicate that PKA rapidly enhances proteasome assembly and activity in in vivo hearts. Further investigation will be needed to clarify pathophysiological roles of PKA-mediated proteasome activation in ischemia/reperfusion hearts.
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PMID:PKA rapidly enhances proteasome assembly and activity in in vivo canine hearts. 1905 65

The achievements of burn metabolism and nutrition in China are briefly presented. Advance a new theory "Enterogenous Hypermetabolism". Develop a formula to calculate calorie needs in Chinese burn adults. Put forward new ideas on glucose absorption, neo glycogenesis, insulin resistance, and the use of hypoglycemic agent after burn injury. Observe the variation of plasma level of free aminoacids, investigate the changes and mechanisms of 26S proteasome and 19S regulator in skeletal muscle of burn trauma, and the clinical application and its mechanism of glutamine and arginine. Introduce the approach of (13)C NMR spectroscopy to investigate the alterations of hepatic anabolism functions in severely burned rats. Offer supplying the suitable dosage of vitamin A, C, E and microelement of zinc, copper, ferrum for burn patients. Carry out serial studies of early enteral and parenteral nutrition, and compare enteral nutrition with parenteral nutrition. Early enteral nutrition with synbiotics might be beneficial to the controlling of burn infection. Both glucagon like peptide-2 (GLP-2) and intestinal trefoil factor (ITF) exhibit protective effect on intestinal mucosa in minimizing injury and protecting barrier function. The choice of suitable opportunity to use rhGH (growth hormone) is investigated. In addition, advance the view points of ischemia and anoxia in metabolism, anti-inflammatory immune and nutrition.
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PMID:[Progress of burn research in metabolism and nutrition in China]. 1910 30

Atrogin-1/MAFbx is a major atrophy-related E3 ubiquitin ligase that is expressed specifically in striated muscle. Although the contribution of atrogin-1 to cardiac and muscle hypertrophy/atrophy has been examined extensively, it remains unclear whether atrogin-1 plays an essential role in the simulated ischemia/reperfusion-induced apoptosis of primary cardiomyocytes. Here we showed that atrogin-1 markedly enhanced ischemia/reperfusion-induced apoptosis in cardiomyocytes via activation of JNK signaling. Overexpression of atrogin-1 increased phosphorylation of JNK and c-Jun and decreased phosphorylation of Foxo3a. In addition, atrogin-1 decreased Bcl-2, increased Bax, and enhanced the activation of caspases. Furthermore, JNK inhibitor SP600125 markedly blocked the effect of atrogin-1 on cell apoptosis and the expression of apoptotic-related proteins and caspases. Importantly, atrogin-1 induced sustained activation of JNK through a mechanism that involved degradation of MAPK phosphatase-1 (MKP-1) protein. Atrogin-1 interacted with and triggered MKP-1 for ubiquitin-mediated degradation. In contrast, proteasome inhibitors markedly blocked the degradation of MKP-1. Taken together, these results demonstrate that atrogin-1 promotes degradation of MKP-1 through the ubiquitin-proteasome pathway, thereby leading to persistent activation of JNK signaling and further cardiomyocyte apoptosis following ischemia/reperfusion injury.
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PMID:Atrogin-1/MAFbx enhances simulated ischemia/reperfusion-induced apoptosis in cardiomyocytes through degradation of MAPK phosphatase-1 and sustained JNK activation. 1911 50

In several pathologic conditions, like cardiac ischemia/reperfusion, the sustained elevation of plasma and interstitial catecholamine levels, namely adrenaline (ADR), and the generation of reactive oxygen species (ROS) are hallmarks. The present work aimed to investigate in cardiomyocytes which intracellular signalling pathways are altered by ADR redox ability. To mimic pathologic conditions, freshly isolated calcium tolerant cardiomyocytes from adult rat were incubated with ADR alone or in the presence of a system capable of generating ROS [(xanthine with xanthine oxidase) (X/XO)]. ADR elicited a pro-oxidant signal with generation of reactive species, which was largely magnified by the ROS generating system. However, no change in cardiomyocytes viability was observed. The pro-oxidant signal promoted the translocation to the nucleus of the transcription factors, Heat shock factor-1 (HSF-1) and Nuclear factor-kappaB (NF-kappaB). In addition, proteasome activity was compromised in the experimental groups where the generation of reactive species occurred. The decrease in the proteasome activity of the ADR group resulted from its redox sensitivity, since the activity was recovered by adding the ROS scavenger, tiron. Proteasome inhibition seemed to elicit an increase in HSP70 levels. Furthermore, retention of mitochondrial cytochrome c and inhibition of caspase 3 activity were observed by X/XO incubation in presence or absence of ADR. In conclusion, in spite of all the insults inflicted to the cardiomyocytes, they were capable to activate intracellular responses that enabled their survival. These mechanisms, namely the pathways altered by catecholamine proteasome inhibition, should be further characterized, as they could be of relevance in the ischemia preconditioning and the reperfusion injury.
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PMID:Adrenaline in pro-oxidant conditions elicits intracellular survival pathways in isolated rat cardiomyocytes. 1913 23

Ubiquitin modification targets a protein for rapid degradation by the proteasome. However, polyubiquitination of proteins can result in multiple functions depending on the topology of the ubiquitin chain. Therefore, ubiquitin signaling offers a more complex and versatile biology compared with many other posttranslational modifications. One area of potential for the application of this knowledge is the field of ischemia-induced brain damage, as occurs following a stroke. The ubiquitin proteasome system may exert a dual role on neuronal outcome following ischemia. Harmful ischemia results in an overload of the ubiquitin proteasome system, and blocking the proteasome reduces brain infarction following ischemia. However, the rapid and selective degradation of proteins following brief ischemia results in endogenous protection against ischemia. Therefore, further understanding of the molecular signaling mechanisms that regulate the ubiquitin proteasome system may reveal novel therapeutic targets to reduce brain damage when ischemia is predicted or reduce the activation of the cell death mechanisms and the inflammatory response following stroke. The aim of this review is to discuss some of the recent advances in the understanding of protein ubiquitination and its implications for novel stroke therapies.
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PMID:The role of the ubiquitin proteasome system in ischemia and ischemic tolerance. 1918 75

Hepatic ischemia/reperfusion (I/R) leads to liver injury and dysfunction through the initiation of a biphasic inflammatory response that is regulated by the transcription factor nuclear factor kappaB (NF-kappaB). We have previously shown that there is an age-dependent difference in the injury response to hepatic I/R in mice that correlates with divergent activation of NF-kappaB such that young mice have greater NF-kappaB activation, but less injury than old mice. In this study, we investigated the mechanism by which age alters the activation of NF-kappaB in the liver during I/R. Young (4-5 weeks) and old (12-14 months) mice underwent partial hepatic I/R. Livers were obtained for RNA microarray analysis and protein expression assays. Using microarray analysis, we identified age-dependent differences in the expression of genes related to protein ubiquitinylation and the proteasome. In old mice, genes that are involved in the ubiquitin-proteasome pathway were significantly down-regulated during I/R. Consistent with these findings, expression of a critical proteasome subunit, non-adenosine triphosphatase 4 (PSMD4), was reduced in old mice. Expression of the NF-kappaB inhibitory protein, IkappaB alpha, was increased in old mice and was greatly phosphorylated and ubiquitinylated. The data provide strong evidence that the age-related defect in hepatic NF-kappaB signaling during I/R is a result of decreased expression of PSMD4, a proteasome subunit responsible for recognition and recruitment of ubiquitinylated substrates to the proteasome. It appears that decreased PSMD4 expression prevents recruitment of phosphorylated and ubiquitinylated IkappaB alpha to the proteasome, resulting in a defect in NF-kappaB activation.
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PMID:Age-related decrease in proteasome expression contributes to defective nuclear factor-kappaB activation during hepatic ischemia/reperfusion. 1920 48

D-Serine, an endogenous amino acid, is involved in many physiological processes through its interaction with the glycine binding site of the N-methyl-D-aspartate (NMDA) receptor. It has important roles in development, learning, and cell death signaling. Recent evidence suggests that decreased function of the NMDA receptor is related to the etiology of schizophrenia, and the use of D-serine as add-on therapy is beneficial in alleviating the symptoms of treatment-refractory schizophrenia. The NMDA receptor also plays a major role in neuronal cell death and neurodegeneration mediated by excitatory amino acid toxicity in ischemia, epilepsy, and trauma. Due to its co-activator function, D-serine can markedly potentiate NMDA-mediated excitotoxicity. To investigate potential adverse effects of D-serine treatment, we investigated gene expression changes in the forebrain of male F-344 rats treated with a single intraperitoneal injection of D-serine (5, 20, 50, 200, or 500 mg/kg) at 96 h post-treatment. Gene expression profiling using Affymetrix Rat Genome 230 2.0 arrays revealed that D-serine treatment resulted in up- and down-regulation of 134 and 52 genes, respectively, based on the common genes identified using three statistical methods, i.e. t test (p < 0.01 over two consecutive doses), ANOVA (with adjusted Bonferonni correction for multiple testing) and significance analysis of microarray (SAM). Self organized map (SOM) clustering analysis of the differentially expressed genes showed two clusters, one with all 134 up-regulated probe sets and the other with all 52 down-regulated probe sets. The dose-response pattern of the down-regulated cluster showed nearly a perfect mirror image of that of the up-regulated one. Gene ontology analysis revealed that pathways implicated in neuronal functions and/or neurodegenerative disorders are over-represented among the differentially expressed genes. Specifically, genes involved in vesicle-mediated transport, endocytosis, ubiquitin conjugation pathway, regulation of actin filament polymerization/depolymerization, focal adhesion, Wnt signaling, and insulin signaling were up-regulated, while genes involved in RNA metabolism/splicing/processing and Notch signaling were down-regulated. Consistent with this finding, pathway analysis using GenMAPP showed a significant number of differentially expressed genes in these pathways. In addition, the GenMAPP result also showed activation of the signaling pathways of several proinflammatory cytokines (including IL-2, IL-3, IL-5, IL-6 and TNF-alpha), which might suggest the onset of neuroinflammation. Biological association network analysis showed that several nuclear factors implicated in transcription regulation (including Taf1, Max, Myc, and Hnf4a) are highly connected to a large number of up-regulated genes. While the transcript levels of these transcription factors were not changed, their connections to Ddx3x, a gene involved in mRNA processing and translation initiation, raise the possibility that they may be up-regulated at the post-transcriptional level. The observation that Ubqln1 and Ube2d, two differentially expressed genes involved in ubiquitin-mediated proteolysis and implicated in neurodegenerative disorders, are highly connected in this network suggests a role of ubiquitination proteasome pathway in response to D-serine exposure. This finding is consistent with the result of gene ontology analysis and suggests that D-serine treatment might result in damage to cellular proteins and subsequent up-regulation of ubiquitination proteasome pathway to clear these damaged proteins. In summary, D-serine exposure resulted in perturbation of a number of pathways implicated in neuronal functions and neurodegenerative disorders. However, activation of cellular response to counter the toxic effects of D-serine might be hindered due to the down-regulation of such important cellular machinery like RNA metabolism, splicing and processing. Consequently, cell damage might be further exacerbated. Taken together, these findings highlight the potential impacts of D-serine exposure on neuronal functions.
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PMID:D-Serine exposure resulted in gene expression changes implicated in neurodegenerative disorders and neuronal dysfunction in male Fischer 344 rats. 1921 59

Autophagy plays a critical and seemingly dual-purposed role in cardiomyocytes, being implicated as a mechanism of both cellular survival, for example, during ischemia/reperfusion injury and a mechanism of cell death at stages in which progressive myocyte alterations are beyond repair. This review aims to highlight the current literature as it relates to autophagy in cardiomyocytes. It provides background into the mechanisms of cell death, discusses the details that are known about the ubiquitin proteasome system and autophagy, delves into the pathways that are known to initiate and inhibit autophagy, and comments on the role of autophagy in cardiomyocyte homeostasis and cell death.
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PMID:How does the heart (not) die? The role of autophagy in cardiomyocyte homeostasis and cell death. 1924 Nov 60

Several lines of evidence suggest that the proteasome contributes to ischemia-reperfusion injury (I-RI) of organs. Although I-RI contributes to multiple disease processes in the lung, the regulation of proteasome activities during pulmonary I-RI is unknown. Thus, the authors performed a pilot study to define time-related changes of lung proteasome peptidase activities and to evaluate if possible alterations correspond to morphological and functional consequences of I-RI using a rat model. Animals underwent 120 minutes of unilateral lung ischemia. Ischemic and contralateral lungs were harvested at multiple time points for up to 168 hours of reperfusion (I-R30 min-168 h). Chymotryptic-like (CT-L) and tryptic-like (T-L) proteasome peptidase activities were measured in lung extracts. An early I-R-associated inactivation of proteasome activities paralleled impairment of oxygenation, edema formation, and degree of histopathology, and resolved with restoration of function within 24 to 72 hours. Although functional and histomorphological baseline conditions were still not fully achieved at I-R168h, proteasome activities increased continuously 1.4-fold (CT-L) and 5.7-fold (T-L) until I-R168h. Apparent K(M) values for the CT-L/T-L substrates were not influenced by I-R. This pilot study establishes an initial link between proteasome activities and physiological relevant consequences of lung I-RI, and further points towards a possible role of the proteasome during the postischemic tissue repair process.
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PMID:Proteasome peptidase activities parallel histomorphological and functional consequences of ischemia-reperfusion injury in the lung. 1941 46


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