Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Abnormal smooth-muscle contractility may be a major cause of disease states such as hypertension, and a smooth-muscle relaxant that modulates this process would be useful therapeutically. Smooth-muscle contraction is regulated by the cytosolic Ca2+ concentration and by the Ca2+ sensitivity of myofilaments: the former activates myosin light-chain kinase and the latter is achieved partly by inhibition of myosin phosphatase. The small GTPase Rho and its target, Rho-associated kinase, participate in this latter mechanism in vitro, but their participation has not been demonstrated in intact muscles. Here we show that a pyridine derivative, Y-27632, selectively inhibits smooth-muscle contraction by inhibiting Ca2+ sensitization. We identified the Y-27632 target as a Rho-associated protein kinase, p160ROCK. Y-27632 consistently suppresses Rho-induced, p160ROCK-mediated formation of stress fibres in cultured cells and dramatically corrects hypertension in several hypertensive rat models. Our findings indicate that p160ROCK-mediated Ca2+ sensitization is involved in the pathophysiology of hypertension and suggest that compounds that inhibit this process might be useful therapeutically.
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PMID:Calcium sensitization of smooth muscle mediated by a Rho-associated protein kinase in hypertension. 935 12

We here review mechanisms that can regulate the activity of myosin II, in smooth muscle and non-muscle cells, by modulating the Ca2+ sensitivity of myosin regulatory light chain (RLC) phosphorylation. The major mechanism of Ca2+ sensitization of smooth muscle contraction and non-muscle cell motility is through inhibition of the smooth muscle myosin phosphatase (MLCP) that dephosphorylates the RLC in smooth muscle and non-muscle. The active, GTP-bound form of the small GTPase RhoA activates a serine/threonine kinase, Rho-kinase, that phosphorylates the regulatory subunit of MLCP and inhibits phosphatase activity. G-protein-coupled release of arachidonic acid may also contribute to inhibition of MLCP acting, at least in part, through the Rho/Rho-kinase pathway. Protein kinase C(s) activated by phorbol esters and diacylglycerol can also inhibit MLCP by phosphorylating and thereby activating CPI-17, an inhibitor of its catalytic subunit; this mechanism is independent of the Rho/Rho-kinase pathway and plays only a minor, transient role in the G-protein-coupled mechanism of Ca2+ sensitization. Ca2+ sensitization by the Rho/Rho-kinase pathway contributes to the tonic phase of agonist-induced contraction in smooth muscle, and abnormally increased activation of myosin II by this mechanism is thought to play a role in diseases such as high blood pressure and cancer cell metastasis.
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PMID:Signal transduction by G-proteins, rho-kinase and protein phosphatase to smooth muscle and non-muscle myosin II. 1063 96

Hypercontraction or abnormal contraction of vascular smooth muscle is a major cause of diseases such as hypertension and vasospasm of the coronary and cerebral arteries. A better understanding of the mechanism of regulation of smooth muscle contraction should lead to improved treatments for such diseases. Recent studies have revealed important roles for the small GTPase Rho and its effector, Rho-associated kinase (Rho kinase) in Ca2+ independent regulation of smooth muscle contraction. The Rho-Rho-kinase pathway modulates the level of phosphorylation of the myosin light chain of myosin II, mainly through inhibition of myosin phosphatase, and contributes to agonist-induced Ca2+ sensitization in smooth muscle contraction. Rho-Rho-kinase mechanisms also participate in a variety of the cellular functions of non-muscle cells, such as stress-fibre formation, cytokinesis and cell migration. This review summarizes the role of the Rho-Rho-kinase pathway in contractile processes of smooth muscle and in non-muscle cell functions, and the pathophysiological implications of this pathway.
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PMID:Rho-Rho-kinase pathway in smooth muscle contraction and cytoskeletal reorganization of non-muscle cells. 1116 70

Brain natriuretic peptide (BNP) gene expression accompanies cardiac hypertrophy and heart failure. The vasoconstrictor endothelin-1 (ET) may be involved in the development of these diseases. ET has also been shown to activate phospholipase A(2) (PLA(2)), and the resulting metabolites are important second messengers. We studied how ET and PLA(2) metabolites regulate BNP gene expression. The human BNP (hBNP) promoter (from -1818 to +100) coupled to a luciferase reporter gene was transferred into neonatal ventricular myocytes (NVMs), and luciferase activity was measured as an index of promoter activity. ET induced BNP mRNA in NVMs as assessed by Northern blot. It also stimulated the hBNP promoter, an effect completely inhibited by actinomycin D. To test the involvement of different PLA(2) isoforms, transfected cells were treated with various PLA(2) inhibitors before stimulation with ET. Only Ca(2+)-independent PLA(2) blockade prevented ET-stimulated hBNP promoter activity. The PLA(2) metabolite lysophosphatidic acid (LPA) also activated the hBNP promoter, but arachidonic acid itself did not. ET regulation of the hBNP promoter is pertussis toxin-sensitive. The nonreceptor tyrosine kinase Src and the small GTPase Rac mediate the effects of both ET and LPA in stimulation of the hBNP promoter. We studied the involvement of cis elements in ET-stimulated hBNP promoter activity. Deletion of BNP promoter sequences from -1818 to -408 and from -408 to -40 reduced the effect of ET by 60% and 80%, respectively. Moreover, ET-stimulated luciferase activity was reduced by 50% when the proximal GATA element was mutated. These data suggest that (1) ET activates the hBNP promoter through a transcriptional mechanism; (2) LPA, perhaps generated by iPLA(2), is involved in the effect of ET; (3) Src and Rac mediate ET and LPA stimulation of the hBNP promoter; and (4) ET regulation of the hBNP promoter targets both distal and proximal cis elements.
Hypertension 2001 Feb
PMID:Src and Rac mediate endothelin-1 and lysophosphatidic acid stimulation of the human brain natriuretic peptide promoter. 1123 Mar 22

Chronic inhibition of endothelial NO synthesis by the administration of N(G)-nitro-L-arginine methyl ester (L-NAME) to rats induces early vascular inflammation (monocyte infiltration into coronary vessels and monocyte chemoattractant protein-1 expression) as well as subsequent arteriosclerosis. The small GTPase Rho controls cell adhesion, motility, and proliferation and is activated by several growth factors such as angiotensin II. We investigated the effect of a specific inhibitor of Rho-kinase, Y-27632, in rats treated with L-NAME to determine the role of the Rho/Rho-kinase pathway in the development of arteriosclerosis. We found here increased activity of Rho/Rho-kinase after L-NAME administration and its prevention by angiotensin II type 1 receptor blockade. Hydralazine or lecithinized superoxide dismutase (l-SOD) did not affect Rho/Rho-kinase activity. Co-treatment with Y-27632 did not affect the L-NAME-induced increase in cardiovascular tissue ACE activity or L-NAME-induced decrease in plasma NO concentrations, but did prevent the L-NAME-induced early inflammation and late coronary arteriosclerosis. In addition, Y-27632 prevented the increased gene expression of monocyte chemoattractant protein-1 and transforming growth factor-beta1 as well as cardiac fibrosis and glomerulosclerosis. These findings suggest that increased activity of Rho/Rho-kinase pathway mediated via the angiotensin II type 1 receptor may thus be important in the pathogenesis of early vascular inflammation and late remodeling induced by chronic inhibition of NO synthesis. The beneficial effects of Rho-kinase inhibition are not mediated by restoration of NO production. The Rho-kinase pathway could be a new therapeutic target for treatment of vascular diseases.
Hypertension 2002 Feb
PMID:Important role of Rho-kinase in the pathogenesis of cardiovascular inflammation and remodeling induced by long-term blockade of nitric oxide synthesis in rats. 1184 92

Abnormal contraction of vascular smooth muscle contributes to a variety of diseases such as hypertension and vasospasm in coronary and cerebral arteries. An increment in a cytoplasmic Ca2+ concentration is the key event in smooth muscle contraction. However, smooth muscle contraction is modified upon the stimulation by agonists as well as in some pathophysiological situations in Ca(2+)-independent mechanism. The molecular mechanism underlying this modulation was not elucidated. Recent studies have shown the important role of small GTPase Rho and its effector, Rho-associated kinase (Rho-kinase)/ROK/ROCK in Ca(2+)-independent regulation of smooth muscle contraction. The Rho/Rho-kinase pathway modulates the phosphorylation level of myosin light chain (MLC) of myosin II, mainly through the inhibition of myosin phosphatase, and contributes to the agonist-induced Ca(2+)-sensitization in smooth muscle contraction. The Rho/Rho-kinase pathway is involved in the pathogenesis of hypertension, vasospasm and arteriosclerosis, and is a potent target of new therapies for these diseases.
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PMID:Smooth muscle contraction by small GTPase Rho. 1208 86

The small GTPase Rho is implicated in many cellular functions such as cell adhesion, cell motility and migration, growth control, cell contraction, and cytokinesis. One of its main effectors, Rho-kinase, appears to play a key role in the regulation of force and velocity of actomyosin crossbridging in smooth muscle and nonmuscle cells by inhibiting myosin phosphatase-mediated dephosphorylation of the regulatory chain of myosin II. Abnormal activation of the Rho/Rho-kinase pathway has been shown to play a role in diseases such as hypertension and bronchial asthma. This review summarizes the current knowledge on the physiological and pathophysiological function of the Rho/Rho-kinase mediated pathway in various tissues with a focus on its possible role as a target for therapeutic interventions.
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PMID:Rho/Rho-kinase mediated signaling in physiology and pathophysiology. 1239 47

Cell adhesion to fibronectin results in formation of actin stress fibres and focal adhesions. In fibroblasts, this response requires two co-operative signals provided by interactions of the RGD sequence with alpha5beta1 integrin and the heparin-binding domain II (Hep II) domain with syndecan-4. Within Hep II, this activity was mapped to repeat III13 and to the peptide FN-C/H-V(WQPPRARITGY, repeat III14). We previously described that the synthetic heparin-binding peptide/III5 (HBP/III5) (WTPPRAQITGYRLTVGLTRR, repeat III5) binds heparin and mediates cell adhesion via chondroitin sulphate proteoglycans. We have now studied whether HBP/III5 co-operates with alpha5beta1 and drives a full cytoskeletal response in melanoma cells. SKMEL-178 cells attached and spread on the RGD-containing FNIII7-FNIII10 (FNIII7-10) fragment, but did not form stress fibres or focal adhesions. Co-immobilization of HBP/III5 with FNIII7-10 or adding soluble HBP/III5 to cells prespread on FNIII7-10, effectively induced these structures. Cell transfection with dominant-negative N19RhoA, a member of the small GTPase family, abolished the HBP/III5 effect. Both chondroitinase and heparitinase diminished focal adhesions, indicating that both types of proteoglycans bound HBP/III5 in melanoma cells. We have mapped the active sequence of HBP/III5 to YRLTVGLTRR, which is a novel sequence in fibronectin with focal-adhesion-promoting activity. The last two arginine (R) residues of this sequence are required for activity, since their replacement by alanine completely abrogated the HBP/III5 cytoskeletal effect. Moreover, this sequence is also active in the context of large fibronectin fragments. Our results establish that the Hep III region provides co-operative signals to alpha5beta1 for the progression of the cytoskeletal response and that these include activation of RhoA.
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PMID:A synthetic peptide from the heparin-binding domain III (repeats III4-5) of fibronectin promotes stress-fibre and focal-adhesion formation in melanoma cells. 1251 80

Although hypertension is a major risk factor for atherosclerosis, its underlying mechanisms remain to be delineated. We have recently reported that both endothelin-1 (ET-1) and vascular cellular adhesion molecule-1 (VCAM-1) levels, key early markers of atherosclerosis, are significantly elevated in carotid arteries of deoxycorticosterone acetate (DOCA)-salt hypertensive rats, a model known for its suppressed plasma renin levels. This study tested the hypothesis that ET-1 augments arterial VCAM-1 expression through NADPH oxidase-derived superoxide (O2-). Carotid arteries of DOCA-salt or sham-operated rats were transduced ex vivo with extracellular superoxide dismutase (EC-SOD), dominant negative HA-tagged N17Rac1 that inhibits Rac1, the small GTPase component of NADPH oxidase, or beta-galactosidase (beta-gal) reporter gene (5x10(10) plaque formation units [pfu]/mL), and the effect of transgene expression on O2- and VCAM-1 levels was assayed 24 hours afterward. The arterial activity of NADPH oxidase but not xanthine oxidase was significantly higher in DOCA-salt than in sham rats, which was abolished by the selective ETA receptor antagonist ABT-627 (3x10(-8) mol/L), NADPH oxidase inhibitor apocynin (10(-4) mol/L), or dominant negative Rac1 gene transfer. The levels of O2- and VCAM-1 were significantly increased in arteries of DOCA-salt rats, an effect that was ameliorated after EC-SOD or dominant negative Rac1 but not beta-gal reporter gene transfer. ABT-627 and apocynin also significantly reduced elevated VCAM-1 levels in ET-1-treated arteries of normal rats and arteries of DOCA-salt rats. The results of this study indicate that ET-1 stimulates arterial VCAM-1 expression by producing O2- from an ETA receptor/NADPH oxidase pathway in low-renin mineralocorticoid hypertension.
Hypertension 2003 Nov
PMID:Endothelin-1 stimulates arterial VCAM-1 expression via NADPH oxidase-derived superoxide in mineralocorticoid hypertension. 1451 26

The serine/threonine protein kinase Rho kinase, a downstream effector of the small GTPase Rho, regulates actin cytoskeletal organization, cell adhesion, cell motility, smooth muscle contraction and gene expression. Rho kinase constitutes the essential regulatory system for myosin phosphatase, controlling myosin light chain phosphorylation and thereby vascular tone. Inhibitors of Rho kinase were shown to be effective in ameliorating hypertension, vasospasm, vascular injury and associated organ damages in various animal disease models. These recent observations imply potential usefulness of the Rho kinase inhibitors as novel therapeutic and preventive agents for vascular disorders and accompanying organ injury.
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PMID:[Rho-Rho kinase pathway]. 1473 34


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