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

The loss of ability to proliferate (terminal differentiation) and reduction in capability to resist ischemia are key phenomena observed during postnatal development of the heart. Mitogen-activated protein kinases (MAPKs) mediate signaling pathways for cell proliferation/differentiation and stress responses such as ischemia. In this study, the expression of these kinases and their associated kinases were investigated in rat heart ventricle. Extracts of 1-, 10-, 20-, 50-, and 365-day-old rat heart ventricles were probed with specific antibodies and their immunoreactivities were quantified by densitometry. Most of the mitogenic protein kinases including Raf1, RafB, Mek1, Erk2, and Rsk1 were significantly down-regulated, whereas the stress signaling kinases, such as Mlk3, Mekkl, Sekl, Mkk3, and Mapkapk2 were up-regulated in expression during postnatal development. Most MAP kinases including Erk1, JNKs, p38 Hog, as well as Rsk2, however, did not exhibit postnatal changes in expression. The proto-oncogene-encoded kinases Mos and Cot/Tpl 2 were up-regulated up to two- and four-fold, respectively, during development. Pakl, which may be involved in the regulation of cytoskeleton as well as in stress signaling, was downregulated with age, but the Pak2 isoform increased only after 50 days. All of these proteins, except RafB, were also detected in the isolated adult ventricular myocytes at comparable levels to those found in adult ventricle. Tissue distribution studies revealed that most of the protein kinases that were up-regulated during heart development tended to be preferentially expressed in heart, whereas the downregulated protein kinases were generally expressed in heart at relatively lesser amounts than in most of other tissues.
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PMID:Expression of mitogen-activated protein kinase pathways during postnatal development of rat heart. 977 26

Myocardial adaptation to ischemia has been shown to activate protein tyrosine kinase, potentiating activation of phospholipase D, which leads to the stimulation of mitogen-activated protein (MAP) kinases and MAP kinase-activated protein (MAPKAP) kinase 2. The present study sought to further examine the signal transduction pathway for the MAPKAP kinase 2 activation during ischemic adaptation. Isolated perfused rat hearts were adapted to ischemic stress by repeated ischemia and reperfusion. Hearts were pretreated with genistein to block tyrosine kinase, whereas SB-203580 was used to inhibit p38 MAP kinases. Western blot analysis demonstrated that p38 MAP kinase is phosphorylated during ischemic stress adaptation. Phosphorylation of p38 MAP kinase was blocked by genistein, suggesting that activation of p38 MAP kinase during ischemic adaptation is mediated by a tyrosine kinase signaling pathway. MAPKAP kinase 2 was estimated by following in vitro phosphorylation with recombinant human heat shock protein 27 as specific substrate for MAPKAP kinase 2. Again, both genistein and SB-203580 blocked the activation of MAPKAP kinase 2 during myocardial adaptation to ischemia. Immunofluorescence microscopy with anti-p38-antibody revealed that p38 MAP kinase is primarily localized in perinuclear regions. p38 MAP kinase moves to the nucleus after ischemic stress adaptation. After ischemia and reperfusion, cytoplasmic striations in the myocytes become obvious, indicating translocation of p38 MAP kinase from nucleus to cytoplasm. Corroborating these results, myocardial adaptation to ischemia improved the left ventricular functions and reduced myocardial infarction that were reversed by blocking either tyrosine kinase or p38 MAP kinase. These results demonstrate that myocardial adaptation to ischemia triggers a tyrosine kinase-regulated signaling pathway, leading to the translocation and activation of p38 MAP kinase and implicating a role for MAPKAP kinase 2.
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PMID:Ischemic preconditioning triggers tyrosine kinase signaling: a potential role for MAPKAP kinase 2. 981 94

The current study focuses on the role of p38 MAP kinase in response to acute preconditioning stimuli and ischemia. Exposure of the rat myoblast cell line H9C2 to preconditioning stimuli, viz. brief duration of ischemia (metabolic inhibition) and adenosine, led to activation of p38 MAP kinase. The protective preconditioning effect of these stimuli against lethal ischemic insult was abolished in the presence or p38 MAP kinase inhibitor SB 203580 but not in the presence of MEK inhibitor PD 98509. Phorbol myristate acetate, PMA, which activates protein kinase C, PKC, activates p38 MAP kinase. and this activation is inhibited by PKC inhibitor G. 6850. The preconditioning effect of PMA was abolished by SB 203580 and also by protein kinase C inhibitor Go 6850. This indicates that the protective action of preconditioning by PKC is mediated via activation of p38 MAP kinase. Paradoxically, the presence of SB 203580 and Go 6850 during the lethal stress protected the cells against cell death. The mode of cell death in this study whether necrotic or apoptotic has not been established. Lethal ischemic stress activates p38 MAP kinase. Preconditioning the cells decreases the activation of p38 MAP kinase in response to the second lethal stress. These findings highlight the role of p38 MAP kinase in ischemic preconditioning v ischemia. Furthermore, our findings in an in vitro model using a proliferating cell line indicate that the duration and/or intensity of stimuli activating p38 kinase probably determines whether it would play a beneficial v deleterious role in cell survival in response to stress.
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PMID:Role of p38 MAP kinase in myocardial stress. 984 Dec 66

We have demonstrated that the ischemia-induced apoptosis of neurons in the CA1 region of the rat hippocampus was prevented by either intracerebroventricular or intravenous infusion of pituitary adenylate cyclase-activating polypeptide (PACAP). However, the molecular mechanisms underlying the anti-apoptotic effect of PACAP remain to be determined. Within 3-6 h after ischemia, the activities of members of the mitogen-activated protein (MAP) kinase family, including extracellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK)/stress-activated protein kinase (SAPK), and p38 were increased in the hippocampus. The ischemic stress had a potent influence on the MAP kinase family, especially on JNK/SAPK. PACAP inhibited the activation of JNK/SAPK after ischemic stress. Secretion of interleukin-6 (IL-6) into the cerebrospinal fluid was intensely stimulated after PACAP infusion. IL-6 inhibited the activation of JNK/SAPK, while it activated ERK. These observations suggest that PACAP and IL-6 act to inhibit the JNK/SAPK signaling pathway, thereby protecting neurons against apoptosis.
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PMID:PACAP protects hippocampal neurons against apoptosis: involvement of JNK/SAPK signaling pathway. 992 3

Cellular ischemia results in activation of a number of kinases, including p38 mitogen-activated protein kinase (MAPK); however, it is not yet clear whether p38 MAPK activation plays a role in cellular damage or is part of a protective response against ischemia. We have developed a model to study ischemia in cultured neonatal rat cardiac myocytes. In this model, two distinct phases of p38 MAPK activation were observed during ischemia. The first phase began within 10 min and lasted less than 1 h, and the second began after 2 h and lasted throughout the ischemic period. Similar to previous studies using in vivo models, the nonspecific activator of p38 MAPK and c-Jun NH2-terminal kinase, anisomycin, protected cardiac myocytes from ischemic injury, decreasing the release of cytosolic lactate dehydrogenase by approximately 25%. We demonstrated, however, that a selective inhibitor of p38 MAPK, SB 203580, also protected cardiac myocytes against extended ischemia in a dose-dependent manner. The protective effect was seen even when the inhibitor was present during only the second, sustained phase of p38 MAPK activation. We found that ischemia induced apoptosis in neonatal rat cardiac myocytes and that SB 203580 reduced activation of caspase-3, a key event in apoptosis. These results suggest that p38 MAPK induces apoptosis during ischemia in cardiac myocytes and that selective inhibition of p38 MAPK could be developed as a potential therapy for ischemic heart disease.
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PMID:An inhibitor of p38 mitogen-activated protein kinase protects neonatal cardiac myocytes from ischemia. 1003 15

Transient global ischemia caused by 5 min of cardiac arrest induced delayed neuronal cell death (apoptosis) in the CA1 region of the rat hippocampus. To characterize the molecular mechanisms that regulate apoptosis in vivo, the contributions to cell death of mitogen-activated protein kinase family members were examined in the hippocampal region after brain ischemia-reperfusion. Ischemia-reperfusion led to a strong activation of the JNK/SAPK (c-Jun NH2-terminal protein kinase/stress activated protein kinase), ERK (extracellular signal-regulated kinase), and p38 enzymes. These results with other previous studies suggest that the activation of JNK/SAPK in accordance with p38 contributes to the induction of apoptosis in CA1 neurons.
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PMID:Delayed neuronal cell death in the rat hippocampus is mediated by the mitogen-activated protein kinase signal transduction pathway. 1007 72

Small heat shock proteins (hsp) have been implicated in mediation of classic preconditioning in the rabbit, Hsp27 is a terminal substrate of the p38 MAPK cascade. One and 2D gel electrophoresis and immunoblotting of cell fractions was used to determine p38 MAPK and hsp27 phosphorylation levels, respectively, during in vitro ischemia in control, calyculin A (Cal A)-treated (protein phosphatase inhibitor), SB203580-treated (p38MAPK inhibitor) and preconditioned (IPC) isolated adult rabbit cardiomyocytes. The dual phosphorylation of p38 MAPK was increased by early ischemia (30-60 min), after which there was a loss of total cytosolic p38 MAPK. The ischemic increase of p38 MAPK dual phosphorylation was enhanced by IPC. Cal A strongly activated dual phosphorylation of p38 MAPK in oxygenated cells and this was maintained into early ischemia, SB203580 inhibited the dual phosphorylation of p38 MAPK and attenuated the loss of total cytosolic p38 MAPK. In each protocol, ischemia translocated hsp27 from the cytosolic fraction to the cytoskeletal fraction at similar rates and extents, Hsp27 phosphorylation was quantitated as the fraction of diphosphorylated hsp27, based on IEF mobility shifts of hsp27 phosphorylation isoforms. In oxygenated control cells, cytosolic and cytoskeletal hsp27 was highly phosphorylated. After 90 min ischemia, cytoskeletal hsp27 was markedly dephosphorylated. Cal A slightly increased control cytoskeletal hsp27 phosphorylation. During ischemic incubation, Cal A blocked ischemic dephosphorylation, SB203580 accelerated ischemic hsp27 dephosphorylation and injury, IPC insignificantly decreased the initial rate of ischemic dephosphorylation of hsp27, but not the extent of dephosphorylation in later ischemia. Phosphorylation is regulated by both kinase and phosphatase activities. IPC protection was not correlated with a significant increase in cytosolic or cytoskeletal hsp27 phosphorylation levels during prolonged (> 60-90 min) ischemia.
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PMID:Phosphorylation state of hsp27 and p38 MAPK during preconditioning and protein phosphatase inhibitor protection of rabbit cardiomyocytes. 1019 87

Both mitochondrial ATP-sensitive K+ (KATP) channels and the actin cytoskeleton have been proposed to be end-effectors in ischemic preconditioning (PC). For evaluation of the participation of these proposed end effectors, rabbits underwent 30 min of regional ischemia and 3 h of reperfusion. PC by 5-min ischemia + 10-min reperfusion reduced infarct size by 60%. Diazoxide, a mitochondrial KATP-channel opener, administered before ischemia was protective. Protection was lost when diazoxide was given after onset of ischemia. Anisomycin, a p38/JNK activator, reduced infarct size, but protection from both diazoxide and anisomycin was abolished by 5-hydroxydecanoate (5-HD), an inhibitor of mitochondrial KATP channels. Isolated adult rabbit cardiomyocytes were subjected to simulated ischemia by centrifuging the cells into an oxygen-free pellet for 3 h. PC was induced by prior pelleting for 10 min followed by resuspension for 15 min. Osmotic fragility was assessed by adding cells to hypotonic (85 mosmol) Trypan blue. PC delayed the progressive increase in fragility seen in non-PC cells. Incubation with diazoxide or pinacidil was as protective as PC. Anisomycin reduced osmotic fragility, and this was reversed by 5-HD. Interestingly, protection by PC, diazoxide, and pinacidil could be abolished by disruption of the cytoskeleton by cytochalasin D. These data support a role for both mitochondrial KATP channels and cytoskeletal actin in protection by PC.
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PMID:Ischemic preconditioning depends on interaction between mitochondrial KATP channels and actin cytoskeleton. 1019 63

Ischemic preconditioning is a phenomenon whereby exposure of the myocardium to a brief episode of ischemia and reperfusion markedly reduces tissue necrosis induced by a subsequent prolonged ischemia. Therefore, it is hoped that elucidation of the mechanism of preconditioning will yield therapeutic strategies capable of reducing myocardial infarction. In the rabbit, the brief period of preconditioning ischemia and reperfusion releases adenosine, bradykinin, opioids, and oxygen radicals that summate to induce the translocation and activation of protein kinase C (PKC). PKC appears to be the first element of a complex kinase cascade that is activated during the prolonged ischemia in preconditioned hearts. Current evidence indicates that PKC activates a tyrosine kinase that leads to the activation of p38 mitogen-activated protein (MAP) kinase or JNK, or possibly both. The stimulation of these stress-activated protein kinases ultimately induces the opening of mitochondrial K(ATP) channels that may be the final mediator of protection by ischemic preconditioning.
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PMID:Signal transduction in ischemic preconditioning: the role of kinases and mitochondrial K(ATP) channels. 1035 30

This review will focus on the free radical signaling mechanism of preconditioning. The results from our laboratory as well as studies from other laboratories suggest that reactive oxygen species function as second messenger during myocardial adaptation to ischemia. This review provides evidence for the first time that tyrosine kinase and MAP kinases are the targets for reactive oxygen species generated in the preconditioned myocardium. The finding that p38 MAP kinase might be upstream of NF kappa B further supports our previous reports that MAPKAP kinase 2 could be the most likely link between the preconditioning and adaptation mediated by gene expression. p38 activation appears to be an important step in the translocation and activation of the nuclear transcription factor NF kappa B, which in turn may be involved in the induction of the expression of a variety of stress-inducible genes.
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PMID:Oxygen free radical signaling in ischemic preconditioning. 1041 20


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