Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0151744 (myocardial ischemia)
 31,282 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxidized low density lipoprotein (LDL) is thought to play a major role in atherogenesis. Atherosclerotic arteries exhibit structural changes associated with profound alterations in vascular tone that are potentially involved in arterial spasm and ischemic heart disease. We report here the role of oxidized LDL in the retraction of vascular smooth muscle cells. Mildly oxidized LDL elicited a broad and sustained peak in cytosolic calcium concentration ([Ca2+]i) in cultured arterial smooth muscle cells. Concomitant with the [Ca2+]i rise, oxidized LDL evoked a sustained and intense retraction of smooth muscle cells, as shown by the changes in cross-sectional area of single cells. Cell retraction was dependent on time, the concentration of oxidized LDL, and the level of LDL oxidation (native LDL induced neither a significant [Ca2+]i rise nor cell retraction). Oxidized LDL but not native LDL also elicited a delayed (12 +/- 2 hours) and sustained (14 +/- 2 hours) increase in isometric tension in deendothelialized arterial rings only, thus suggesting a protective role of intact endothelium. When triggered by nontoxic doses of oxidized LDL, retraction of cultured cells and the contractile response of aortic rings was reversible, whereas with higher (toxic) doses (> or = 200 micrograms apoB/mL), cell retraction was irreversible and led progressively to detachment and cell death. Cell retraction can be prevented in three ways: (1) by inhibiting LDL oxidation with supplements of antioxidants (indirect inhibition); (2) by blocking the pathogenic intracellular signaling elicited by oxidized LDL (direct inhibition), eg, by inhibiting calcium influx with EGTA or the calcium channel blocker nisoldipine or by blocking intracellular signaling (at a still-unknown step) by the lipophilic antioxidant alpha-tocopherol; and (3) by directly inhibiting myosin light chain kinase by 1-(5-chloronaphthalene-1-sulfonyl)-1H-hexahydro-1, 4-diazepine. In conclusion, oxidized LDL evoked a sustained and intense calcium-dependent retraction of cultured smooth muscle cell, which can be prevented by inhibiting LDL oxidation or by blocking the intracellular signaling induced by oxidized LDL.
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PMID:Mildly oxidized LDL evokes a sustained Ca(2+)-dependent retraction of vascular smooth muscle cells. 883 13

To profile gene expression patterns involved in ischemic preconditioning, we monitored global gene expression changes by DNA microarray analysis of 3200 rat-specific genes and by real-time quantitative polymerase chain reaction in rat hearts. Forty-nine genes with altered expression were found after ischemia/reperfusion as compared to control non-ischemic hearts and 31 genes were characteristic for classic preconditioning followed by ischemia/reperfusion as compared to ischemia/reperfusion without preconditioning. Genes with altered expression due to ischemia and/or preconditioning included those controlling protein degradation, stress responses, apoptosis, metabolic enzymes, regulatory proteins, and several unknown cellular functions. Metallothionein, natriuretic peptides, coagulation factor VII, cysteine proteinase inhibitor, peroxisome proliferator activator receptor gamma and myosin light chain kinase genes were previously suspected to be related to several cardiovascular diseases, however, most of these genes have not previously been shown to be related to myocardial ischemia/reperfusion. Some genes were observed to change specifically in response to preconditioning: oligoadenylate synthase, chaperonin subunit epsilon, a cGMP phosphodiesterase (PDE9A1), a secretory carrier membrane protein, an amino acid transporter, and protease 28 subunit. None of these genes has previously been shown to be involved in the mechanism of preconditioning.
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PMID:Effect of classic preconditioning on the gene expression pattern of rat hearts: a DNA microarray study. 1258 34

Nuclear myosin regulates gene transcription and this novel function might be modulated through phosphorylation of the myosin regulatory light chain (p-MLC20). Nonmuscle MLC20 (nmMLC20) is also present in the nuclei of cardiomyocytes and a potential nmMLC20 binding sequence has been identified in the promoter of the xanthine oxidase (XO) gene. Thus, we investigated its function in the regulation of XO transcription after myocardial ischemia/reperfusion (IR). In a rat model of myocardial IR and a cardiomyocyte model of hypoxia/reoxygenation (HR) injury, the cardiac or cell injury, myosin light chain kinase (MLCK) content, XO expression and activity, XO-derived products, and level of nuclear p-nmMLC20 were detected. Coimmunoprecipitation (co-IP), chromatin immunoprecipitation, DNA pull-down, and luciferase reporter gene assays were used to decipher the molecular mechanisms through which nmMLC20 promotes XO expression. IR or HR treatment dramatically elevated nuclear p-nmMLC20 level, accompanied by increased XO expression, activity, and products (H2O2 and uric acid), as well as the IR or HR injury; these effects were ameliorated by inhibition of MLCK or knockdown of nmMLC20. Our findings from these experiments demonstrated that nuclear p-nmMLC20 binds to the consensus sequence GTCGCC in the XO gene promoter, interacts with RNA polymerase II and transcription factor IIB to form a transcription preinitiation complex, and hence activates XO gene transcription. These results suggest that nuclear p-nmMLC20 plays an important role in IR/HR injury by transcriptionally upregulating XO gene expression to increase oxidative stress in myocardium. Our findings demonstrate nuclear nmMLC20 as a potential new therapeutic target to combat cardiac IR injury.
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PMID:A novel function of nuclear nonmuscle myosin regulatory light chain in promotion of xanthine oxidase transcription after myocardial ischemia/reperfusion. 2570 32

Matrix metalloproteinase-2 (MMP-2) mediated degradation of myosin light chain 1 (MLC1) and troponin I (TnI) contributes to myocardial ischemia/reperfusion (I/R) injury. Modifications of MLC1 triggered by oxidative stress are mediated by myosin light chain kinase (MLCK), nitric oxide synthase (NOS), and MMP-2. Previous studies have shown that inhibiting both MLCK and MMP-2 protects against I/R injury. Here, we hypothesized that the addition of NOS inhibitor (L-NAME) at subprotective concentration to the mixture of subprotective concentrations of ML-7 and doxycycline (Doxy), will increase a synergistic cardioprotection of Doxy and ML-7 during I/R. Isolated rat hearts were subjected to global ischemia without or with administration of the mixture of inhibitors. Markers of I/R injury were measured in hearts and coronary effluents. Addition of L-NAME to the mixture of Doxy and ML-7 led to full recovery of heart contractility in comparison to combination of Doxy and ML-7. Improved heart contractility was associated with reduced degradation of TnI and MLC1. The combined administration of NOS, MMP-2 and MLCK inhibitors provides a novel strategy to protect heart from I/R injury.
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PMID:L-NAME improves doxycycline and ML-7 cardioprotection from oxidative stress. 2893 May 48