Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The epoxyeicosatrienoic acids (EETs) are products of cytochrome P450 (CYP) epoxygenases that have vasodilatory and anti-inflammatory properties. Here we report that EETs have additional fibrinolytic properties. In vascular endothelial cells, physiological concentrations of EETs, particularly 11,12-EET, or overexpression of the endothelial epoxygenase, CYP2J2, increased tissue plasminogen activator (t-PA) expression by 2.5-fold without affecting plasminogen activator inhibitor-1 expression. This increase in t-PA expression correlated with a 4-fold induction in t-PA gene transcription and a 3-fold increase in t-PA fibrinolytic activity and was blocked by the CYP inhibitor, SKF525A, but not by the calcium-activated potassium channel blocker, charybdotoxin, indicating a mechanism that does not involve endothelial cell hyperpolarization. The t-PA promoter is cAMP-responsive, and induction of t-PA gene transcription by EETs correlated with increases in intracellular cAMP levels and, functionally, with cAMP-driven promoter activity. To determine whether increases in intracellular cAMP levels were due to modulation of guanine nucleotide-binding proteins, we assessed the effects of EETs on Galpha(s) and Galpha(i2). Treatment with EETs increased Galpha(s), but not Galpha(i2), GTP-binding activity by 3.5-fold. These findings indicate that EETs possess fibrinolytic properties through the induction of t-PA and suggest that endothelial CYP2J2 may play an important role in regulating vascular hemostasis.
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PMID:Activation of Galpha s mediates induction of tissue-type plasminogen activator gene transcription by epoxyeicosatrienoic acids. 1127 71

We used the patch-clamp technique to examine the effect of adenosine on epithelial sodium channel (ENaC) activity in rat cortical collecting duct (CCD). Application of adenosine inhibits ENaC activity, and the effect of adenosine was mimicked by cyclohexyladenosine (CHA), an A(1) adenosine-receptor agonist that reduced channel activity from 1.32 to 0.64. The inhibitory effect of CHA on ENaC was mimicked by cyclopentyladenosine (CPA), which reduced channel activity from 1.1 to 0.55. In contrast, application of CGS-21680, an A(2a) adenosine-receptor agonist, had no effect on ENaC and increased channel activity from 0.96 to 1.22. This suggests that the inhibitory effect of adenosine analogs resulted from stimulation of the A(1) adenosine receptor. Inhibition of PLC with U-73122 failed to abolish the effect of CHA on ENaC. In contrast, the inhibitory effect of CHA on ENaC was absent in the presence of the PLA(2) inhibitor arachidonyl trifluoromethyl ketone (AACOCF(3)). This suggests a role of arachidonic acid (AA) in mediating the effect of adenosine on ENaC. To determine the metabolic pathway of AA responsible for the effect of adenosine, we examined the effect of CHA in the presence of indomethacin or N-methylsulfonyl-6-(2-propargyloxyphenyl)hexanamide (MS-PPOH). Inhibition of cytochrome P-450 (CYP) epoxygenase with MS-PPOH blocked the effect of CHA on ENaC. In contrast, CHA reduced ENaC activity in the presence of indomethacin. This suggests that CYP epoxygenase-dependent metabolites of AA mediate the effect of adenosine. Because 11,12-epoxyeicosatrienoic acid (11,12-EET) inhibits ENaC activity in the CCD (Wei Y, Lin DH, Kemp R, Yaddanapudi GSS, Nasjletti A, Falck JR, and Wang WH. J Gen Physiol 124: 719-727, 2004), we examined the role of 11,12-EET in mediating the effect of adenosine on ENaC. Addition of 11,12-EET inhibited ENaC channels in the CCD in which adenosine-induced inhibition was blocked by AACOCF3. We conclude that adenosine inhibits ENaC activity by stimulation of the A(1) adenosine receptor in the CCD and that the effect of adenosine is mediated by 11,12-EET.
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PMID:Adenosine inhibits ENaC via cytochrome P-450 epoxygenase-dependent metabolites of arachidonic acid. 1623 12