Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.24 (mitogen-activated protein kinase)
 95,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study was designed to determine the effect of all-trans retinoic acid (RA) on the development of cardiac remodeling in a pressure overload rat model. Male Sprague-Dawley rats were subjected to sham operation and the aortic constriction procedure. A subgroup of sham control and aortic constricted rats were treated with RA for 5 mo after surgery. Pressure-overloaded rats showed significantly increased interstitial and perivascular fibrosis, heart weight-to-body weight ratio, and gene expression of atrial natriuretic peptide and brain natriuretic peptide. Echocardiographic analysis showed that pressure overload induced systolic and diastolic dysfunction, as evidenced by decreased fractional shortening, ejection fraction, stroke volume, and increased E-to-E(a) ratio and isovolumic relaxation time. RA treatment prevented the above changes in cardiac structure and function and hypertrophic gene expression in pressure-overloaded rats. RA restored the ratio of Bcl-2 to Bax, inhibited cleavage of caspase-3 and -9, and prevented the decreases in the levels of SOD-1 and SOD-2. Pressure overload-induced phosphorylation of ERK1/2, JNK, and p38 was inhibited by RA, via upregulation of mitogen-activated protein kinase phosphatase (MKP)-1 and MKP-2. The pressure overload-induced production of angiotensin II was inhibited by RA via upregulation of expression of angiotensin-converting enzyme (ACE)2 and through inhibition of the expression of cardiac and renal renin, angiotensinogen, ACE, and angiotensin type 1 receptor. Similar results were observed in cultured neonatal cardiomyocytes in response to static stretch. These results demonstrate that RA has a significant inhibitory effect on pressure overload-induced cardiac remodeling, through inhibition of the expression of renin-angiotensin system components.
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PMID:All-trans retinoic acid prevents development of cardiac remodeling in aortic banded rats by inhibiting the renin-angiotensin system. 1817 13

We demonstrated previously that, in mice with chronic angiotensin II-dependent hypertension, gp91phox-containing NADPH oxidase is not involved in the development of high blood pressure, despite being important in redox signaling. Here we sought to determine whether a gp91phox homologue, Nox1, may be important in blood pressure elevation and activation of redox-sensitive pathways in a model in which the renin-angiotensin system is chronically upregulated. Nox1-deficient mice and transgenic mice expressing human renin (TTRhRen) were crossed, and 4 genotypes were generated: control, TTRhRen, Nox1-deficient, and TTRhRen Nox1-deficient. Blood pressure and oxidative stress (systemic and renal) were increased in TTRhRen mice (P<0.05). This was associated with increased NADPH oxidase activation. Nox1 deficiency had no effect on the development of hypertension in TTRhRen mice. Phosphorylation of c-Src, mitogen-activated protein kinases, and focal adhesion kinase was significantly increased 2- to 3-fold in kidneys from TTRhRen mice. Activation of c-Src, p38 mitogen-activated protein kinase, c-Jun N-terminal kinase, and focal adhesion kinase but not of extracellular signal regulated kinase 1/2 or extracellular signal regulated kinase 5, was reduced in TTRhRen/Nox1-deficient mice (P<0.05). Expression of procollagen III was increased in TTRhRen and TTRhRen/Nox1-deficient mice versus control mice, whereas vascular cell adhesion molecule-1 was only increased in TTRhRen mice. Our findings demonstrate that, in Nox1-deficient TTRhRen mice, blood pressure is elevated despite reduced NADPH oxidase activation, decreased oxidative stress, and attenuated redox signaling. Our results suggest that Nox1-containing NADPH oxidase plays a key role in the modulation of systemic and renal oxidative stress and redox-dependent signaling but not in the elevation of blood pressure in a model of chronic angiotensin II-dependent hypertension.
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PMID:Renal redox-sensitive signaling, but not blood pressure, is attenuated by Nox1 knockout in angiotensin II-dependent chronic hypertension. 1819 61

The (pro)renin receptor [(P)RR], a new component the renin-angiotensin system, was cloned recently. The (P)RR promotes direct mitogen-activated protein kinase signaling and nonproteolytic prorenin activation. We investigated the role of a (P)RR blocker, a peptide consisting of 10 amino acids from the prorenin prosegment called the "handle-region" peptide (HRP), on target organ damage in renovascular hypertensive 2-kidney, 1-clip (2K1C) rats. Vehicle-treated 2K1C rats were compared with HRP-treated 2K1C rats (3.5 mug/kg per day) and sham-operated controls. Vehicle-treated 2K1C rats developed hypertension (186+/-17 mm Hg), cardiac hypertrophy (3.16+/-0.16 mg/g), renal inflammation, fibrosis, vascular, and tubular damage. Chronic HRP treatment did not affect blood pressure (194+/-15 mm Hg), cardiac hypertrophy (2.97+/-0.11 mg/g), or renal damage. Furthermore, we investigated the renal renin and (P)RR expression. The clipped kidney of 2K1C and HRP-treated 2K1C rats showed a higher renin expression and juxtaglomerular index compared with sham-operated kidneys. The unclipped kidney showed suppressed renin expression. In contrast, (P)RR mRNA expression was not altered in any group. Plasma renin activity and aldosterone were increased in 2K1C rats compared with sham controls. HRP-treated 2K1C rats tended to lower plasma renin activity but showed similar aldosterone levels as vehicle-treated 2K1C rats. Our results indicate that blockade of the (P)RR with HRP does not improve target organ damage in renovascular hypertensive rats.
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PMID:(Pro)renin receptor peptide inhibitor "handle-region" peptide does not affect hypertensive nephrosclerosis in Goldblatt rats. 1821 68

The recently cloned (pro)renin receptor [(P)RR] mediates renin-stimulated cellular effects by activating mitogen-activated protein kinases and promotes nonproteolytic prorenin activation. In vivo, (P)RR is said to be blocked with a peptide consisting of 10 amino acids from the prorenin prosegment called the "handle-region" peptide (HRP). We tested whether human prorenin and renin induce extracellular signal-regulated kinase (ERK) 1/2 activation and whether the direct renin inhibitor aliskiren or the HRP inhibits the receptor. We detected the (P)RR mRNA and protein in isolated human monocytes and in U937 monocytes. In U937 cells, we found that both human renin and prorenin induced a long-lasting ERK 1/2 phosphorylation despite angiotensin II type 1 and 2 receptor blockade. In contrast to angiotensin II-ERK signaling, renin and prorenin signaling did not involve the epidermal growth factor receptor. A mitogen-activated protein kinase kinase 1/2 inhibitor inhibited both renin and prorenin-induced ERK 1/2 phosphorylation. Neither aliskiren nor HRP inhibited binding of (125)I-renin or (125)I-prorenin to (P)RR. Aliskiren did not inhibit renin and prorenin-induced ERK 1/2 phosphorylation and kinase activity. Fluorescence-activated cell sorter analysis showed that, although fluorescein isothiocyanate-labeled HRP bound to U937 cells, HRP did not inhibit renin or prorenin-induced ERK 1/2 activation. In conclusion, prorenin and renin-induced ERK 1/2 activation are independent of angiotensin II. The signal transduction is different from that evoked by angiotensin II. Aliskiren has no (P)RR blocking effect and did not inhibit ERK 1/2 phosphorylation or kinase activity. Finally, we found no evidence that HRP affects renin or prorenin binding and signaling.
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PMID:Prorenin and renin-induced extracellular signal-regulated kinase 1/2 activation in monocytes is not blocked by aliskiren or the handle-region peptide. 1821 69

The (pro)renin receptor [(P)RR] is a single trans-membrane domain receptor that mediates renin and prorenin specific effects. The receptor acts as co-factor for renin and prorenin by increasing their enzymatic activity on the cell-surface and it activates the mitogen activated protein kinases ERK1/2 cascade leading to cell proliferation and to up-regulation of profibrotic genes expression. Studies in genetically modified animals over-expressing (P)RR suggest a direct role for (P)RR cardiovascular and renal pathologies since rats over-expressing (P)RR in vascular smooth-muscle cells develop high blood pressure and those with an ubiquitous over-expression of (P)RR have glomerulosclerosis and proteinuria. A peptide called "handle region peptide" (HRP) mimicking part of the prosegment of prorenin was claimed to block prorenin binding to (P)RR and its activation. The mechanism of action of HRP and its specificity for (P)RR remains very controversial although infusion of this peptide gave spectacular results by preventing diabetic nephropathy in angiotensin II type1a receptor-deficient mice. In contrast to the other components of the renin angiotensin system, (P)RR is necessary to cell survival and proliferation and a mutation of (P)RR is associated with mental retardation and epilepsy, pointing to an essential role of (P)RR in brain development. The (pro)renin receptor is a more complex protein than anticipated and in depth studies of its functions that are likely not restricted to the renin angiotensin system are needed especially in the perspective of the design of a (P)RR blocker.
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PMID:Physiology and pharmacology of the (pro)renin receptor. 1824 93

Macula densa (MD) cells express the Na(+)/H(+) exchanger (NHE) isoform NHE2 at the apical membrane, which may play an important role in tubular salt sensing through the regulation of cell volume and intracellular pH. These studies aimed to determine whether NHE2 participates in the MD control of renin synthesis. Renal renin content and activity and elements of the MD signaling pathway were analyzed using wild-type (NHE2(+/+)) and NHE2 knockout (NHE2(-/-)) mice. Immunofluorescence studies indicated that NHE2(-/-) mice lack NHE3 at the MD apical membrane, so the other apical NHE isoform has not compensated for the lack of NHE2. Importantly, the number of renin-expressing cells in the afferent arteriole in NHE2(-/-) mice was increased approximately 2.5-fold using renin immunohistochemistry. Western blotting confirmed approximately 20% higher renal cortical renin content in NHE2(-/-) mice compared with wild type. No-salt diet for 1 wk significantly increased renin content and activity in NHE2(+/+) mice, but the response was blunted in NHE2(-/-) mice. Renal tissue renin activity and plasma renin concentration were elevated three- and twofold, respectively, in NHE2(-/-) mice compared with wild type. NHE2(-/-) mice also exhibited a significantly increased renal cortical cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase (mPGES) expression, indicating MD-specific mechanisms responsible for the increased renin content. Significant and chronic activation of ERK1/2 was observed in MD cells of NHE2(-/-) kidneys. Removal of salt or addition of NHE inhibitors to cultured mouse MD-derived (MMDD1) cells caused a time-dependent activation of ERK1/2. In conclusion, the NHE2 isoform appears to be important in the MD feedback control of renin secretion, and the signaling pathway likely involves MD cell shrinkage and activation of ERK1/2, COX-2, and mPGES, all well-established elements of the MD-PGE(2)-renin release pathway.
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PMID:Increased renal renin content in mice lacking the Na+/H+ exchanger NHE2. 1828 98

(Pro)renin receptor (PRR), the newest member of the renin-angiotensin system (RAS), is turning out to be an important player in the regulation of the cardiovascular system. It plays a pivotal role in activation of the local RAS and stimulates signalling pathways involved in proliferative and hypertrophic mechanisms. However, the role of PRR in the brain remains unknown. Thus, our objective in this study was to determine whether a functional PRR is present in neurons within the brain. Neuronal co-cultures from the hypothalamus and brainstem areas of neonatal rat brain express PRR mRNA. Immunoreactivity for PRR was primarily localized on the neuronal cell soma and in discrete areas in the neurites. Treatment of neurons with renin, in the presence of 2 microm losartan, caused a time- and dose-dependent stimulation of phosphorylation of extracellular signal related kinase ERK1 (p44) and ERK2 (p42) isoforms of mitogen-activated protein kinase. Optimal stimulation of fourfold was observed within 2 min with 20 nm renin. Electrophysiological recordings showed that treatment of the neurons with renin, in the presence of 2 microm losartan, resulted in a steady and stable decrease in action potential frequency. A 46% decrease in action potential frequency was observed within 5 min of treatment and was attenuated by co-incubation with a PRR blocking peptide. These observations demonstrate that the PRR is present in neurons within the brain and that its activation by renin initiates the MAP kinase signalling pathway and inhibition of neuronal activity.
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PMID:Characterization of a functional (pro)renin receptor in rat brain neurons. 1832 51

Vascular endothelial cells have a finite cell lifespan and eventually enter an irreversible growth arrest, cellular senescence. The functional changes associated with cellular senescence are thought to contribute to human aging and age-related cardiovascular disorders, for example, atherosclerosis. Angiotensin II (Ang II), a principal effector of the renin-angiotensin system (RAS), an important signaling molecule involved in atherogenic stimuli, is known to promote aging and cellular senescence. In the present study, induction of Ang II promoted a growth arrest with phenotypic characteristics of cell senescence, such as enlarged cell shapes, increased senescence-associated beta-galactosidase (SA-beta-gal) positive staining cells, and depressed cell proliferation. Ang II drastically decreased the expression level of Bcl-2, in part via the activation of extracellular signal-regulated kinase (ERK). Our results suggest that Ang II can induce HUVEC senescence; one of its molecular mechanisms is a probability that the mitogen-activated protein kinase (MAPK) signal pathway is involved in the process of pathological and physiological senescence of endothelial cells as well as vascular aging.
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PMID:Angiotensin II induces endothelial cell senescence via the activation of mitogen-activated protein kinases. 1838 64

Angiotensin II (AngII)( *) is the main effector of the renin-angiotensin system and influences cell growth, migration, differentiation, and apoptosis. The mitogen-activated protein (MAP) kinase family of serine-threonine kinases integrates diverse extracellular stimuli and is involved in the regulation of cell growth and apoptosis. AngII regulates activity of the MAP kinase family members extracellular regulated kinases (ERK1/2) and c-Jun N-terminal kinase (JNK). This review discusses the signal transduction pathways leading to ERK1/2 and JNK activation by AngII.
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PMID:Angiotensin II signal transduction: Stimulation of multiple mitogen-activated protein kinase pathways. 1840 13

Atrial fibrillation (AF) is the most common rhythm disturbance in medical practice and represents a very expensive health problem. AF can be managed with the prevention of thromboembolism and either a rate control of rhythm strategy. As both strategies have important limitations, probably a preventative strategy in patients at risk of developing arrhythmia can be a more attractive option. The renin-angiotensin system (RAS) seems to be involved in the genesis of arrhythmia by the following two mechanisms: 1. the induction of atrial fibrosis and structural remodelling by mitogen-activated protein kinase (MAPK) expression and reduction of collagenase activity; 2. the induction of electrical remodelling by shortening of the atrial effective refractory period (AERP) and of the action potential duration. For these reasons it has been hypothesized that angiotensin-converting enzyme inhibitors (ACE-Is) and angiotensin-II receptor blockers (ARBs) may play a role in preventing AF recurrence. The aim of the present review was to analyse evidence supporting the usefulness of RAS inhibition in patients with AF in order to focus on which specific subset of patients it would most favour. After reviewing the literature, we conclude that, although many studies and meta-analysis have supported the advantage of RAS block in preventing AF recurrence, it is premature to recommend the use of ACE-Is and ARBs specifically for the prevention of AF. However we believe that as these drugs are safe and manageable, they should be considered the drugs of choice in patients with AF and coexisting clinical conditions such as hypertension, coronary disease, heart failure and diabetes mellitus.
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PMID:The role of the renin-angiotensin system in atrial fibrillation and the therapeutic effects of ACE-Is and ARBS. 1878 41


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