Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.4.1 (phosphodiesterase)
 18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Essential polyunsatured fatty acids have been shown to modulate enzymes, channels and transporters, to interact with lipid bilayers and to affect metabolic pathways. We have previously shown that eicosapentanoic acid (EPA, C20:5, n-3) activates epithelial sodium channels (ENaCs) in a cAMP-dependent manner involving stimulation of cAMP-dependent protein kinase (PKA). In the present study, we explored further the mechanism of EPA stimulation of ENaC in A6 cells. Fluorescence resonance energy transfer experiments confirmed activation of PKA by EPA. Consistent with our previous studies, EPA had no further stimulatory effect on amiloride-sensitive transepithelial current (INa) in the presence of CPT-cAMP. Thus, we investigated the effect of EPA on cellular pathways which produce cAMP. EPA did not stimulate adenylate cyclase activity or total cellular cAMP accumulation. However, membrane-bound phosphodiesterase activity was inhibited by EPA from 2.46 pmol/mg of protein/min to 1.3 pmol/mg of protein/min. To investigate the potential role of an A-kinase-anchoring protein (AKAP), we used HT31, an inhibitor of the binding between PKA and AKAPs as well as cerulenin, an inhibitor of myristoylation and palmitoylation. Both agents prevented the stimulatory effect of EPA and CPT-cAMP on INa and drastically decreased the amount of PKA in the apical membrane. Colocalization experiments in A6 cells cotransfected with fluorescently labeled ENaC beta subunit and PKA regulatory subunit confirmed the close proximity of the two proteins and the membrane anchorage of PKA. Last, in A6 cells transfected with a dead mutant of Sgk, an enzyme which up-regulates ENaCs, EPA did not stimulate Na+ current. Our results suggest that stimulation of ENaCs by EPA occurs via SGK in membrane-bound compartments containing an AKAP, activated PKA, and a phosphodiesterase.
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PMID:Epithelial Na+ channel stimulation by n-3 fatty acids requires proximity to a membrane-bound A-kinase-anchoring protein complexed with protein kinase A and phosphodiesterase. 1747 24

Cilostazol (CILO), a selective inhibitor of phosphodiesterase 3 with potent antithrombotic property, has been shown to have a vasculoprotective effect in atherosclerosis animal models due to its potential anti-inflammatory and antioxidant actions. This study was undertaken to investigate whether CILO has in fact any vasculoprotective effects in aldosterone-induced hypertensive rats (Aldo-rats), and whether CILO affects Aldo-induced oxidative stress, nitric oxide (NO) production and pro-inflammatory gene expression. Treatment with CILO markedly ameliorated perivascular inflammatory changes in the coronary arterioles of Aldo-rats without affecting the systolic blood pressure and left ventricular weight. Treatment with CILO also prevented the increase in plasma levels of thiobarbituric acid-reactive substances, an oxidative stress marker, as well as decreased urinary NOx excretion in Aldo-rats. Furthermore, CILO almost completely inhibited a set of upregulated proinflammatory genes (ICAM-1, MCP-1, PDGF-A, osteopontin, MMP-2 and ACE), as well as NAD(P)H oxidase components (p22phox, gp91phox, p47phox) and Aldo-inducible genes (SGK-1 and NHE-1) in the aortic tissues from Aldo-rats. Taken together, this study showed for the first time that CILO prevented Aldo-induced vascular inflammation and injury without affecting the blood pressure, suggesting its vasculoprotective effect on Aldo-induced vascular injury independent of blood pressure.
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PMID:Vasculoprotective effect of cilostazol in aldosterone-induced hypertensive rats. 2001 1