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)

Growth arrest-specific homeobox (Gax) gene was isolated from rat aorta cDNA library and its expression was largely confined to the cardiovascular tissues. Gax gene was rapidly downregulated by platelet-derived growth factor in vascular smooth muscle cells (VSMCs) and overexpressed Gax was reported to reduce the neointimal thickening after balloon injury in vivo. We have demonstrated that angiotensin II (Ang II) stimulates vascular growth. In contrast, we also reported that C-type natriuretic peptide (CNP) is secreted from vascular endothelial cells to act as a novel endothelium-derived relaxing peptide and inhibits vascular growth via cGMP cascade. In the present study, we examined the effects of Ang II and CNP on Gax gene expression in VSMCs. In quiescent rat aortic VSMCs. Gax mRNA (2 3 kb) level became negligible 6 hours after the addition of Ang II (10(-6) mol/L). The inhibitory action of Ang II on Gax mRNA expression (ED50: 10(-11) mol/L) was almost completely blocked by an AT1R antagonist, CV11974. In contrast, CNP 10(-6) mol/L augmented Gax mRNA expression to exhibit 1.8-fold increase of the control 12 hours after the stimulation. This effect of CNP was mimicked by the addition of 8-bromoadenosine 3'-5'-cyclic monophosphate. The addition of C-ANF[4-23], an atrial natriuretic peptide-C receptor-specific agonist and devoid of stimulating cGMP production, exhibited no effect on Gax mRNA expression. Simultaneous administration of Ang II and CNP revealed that CNP (10(-6) mol/L) significantly attenuated the inhibitory action of Ang II (10(-10) mol/L) on Gax mRNA expression. These results suggest that Gax is a common transcription factor involved in the signaling pathway of vascular growth for Ang II and CNP and regulates the cell cycle and/or phenotype of VSMCs for vascular remodeling in hypertension and atherosclerosis.
Hypertension 1997 Jan
PMID:Opposite regulation of Gax homeobox expression by angiotensin II and C-type natriuretic peptide. 903 31

Hypertension, diabetes mellitus and chronic glomerular diseases reportedly cause in excess of 80% of the incident cases of end-stage renal disease (ESRD) in the U.S. The factors that initiate progressive renal failure in patients with these disorders remain unknown. Several investigators have reported enhanced synthesis and activity of cytokines in the kidneys of patients with renal failure. The ensuing inflammation and fibrosis have been postulated to contribute to the development of progressive renal failure. There is also abundant evidence supporting the contribution of genetic factors in ESRD susceptibility based upon the strong familial clustering of ESRD, particularly in African Americans. Therefore, genetic linkage analysis may be useful to evaluate the role of candidate genes in several cytokine cascades that could contribute to the pathogenesis of chronic renal failure. We tested for genetic linkage between eight cytokine candidate genes and chronic renal failure in a collection of African American sibling pairs concordant for ESRD. Epidermal growth factor (EGF), platelet-derived growth factor (PDGF), transforming growth factor (TGF) beta 1, TGF-beta 2 and TGF-beta 3, and tumor necrosis factor (TNF)-alpha and TNF-beta candidate genes were selected for analysis due to their putative roles in diabetic renal disease and chronic glomerulonephritis. The interleukin-1 receptor antagonist gene (IL1RN) was also genotyped due to its reported association with diabetic nephropathy. Non-parametric (genetic model independent) affected sib pair linkage analysis was used to evaluate evidence for linkage. In order to genotype TGF-beta 3, we identified four closely linked, previously unidentified, highly polymorphic microsatellite loci near the TGF-beta 3 gene. Linkage of ESRD and transforming growth factor beta 2 polymorphisms on human chromosome 1 approached significance for non-diabetic nephropathy (predominantly chronic glomerular disease, hypertensive nephrosclerosis and unknown etiology) (P = 0.08), but showed no linkage to diabetic nephropathy. The other candidate loci did not demonstrate linkage to ESRD in the total population or in the subgroups with diabetic or non-diabetic etiologies of ESRD. The IL1RN gene did not show significant evidence for linkage to ESRD; however, we did confirm an association between allele 2 of IL1RN and ESRD (as reported in diabetic nephropathy). Overall, these results suggest that these growth factor loci do not make major contributions to the pathogenesis of ESRD in African Americans.
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PMID:Genetic linkage analysis of growth factor loci and end-stage renal disease in African Americans. 906 16

1. The present study was conducted to analyse the release and production of mitogen in cultured aortic endothelial cells of stroke-prone spontaneously hypertensive rats (SHRSP), for the further understanding of the role of arterial endothelial cells in the genesis of vascular lesions in hypertension. 2. The cultured aortic endothelial cells derived from SHRSP increased released mitogens were compared with those from control Wistar-Kyoto rats (WKY) with respect to cultured vascular medial smooth muscle cells and fibroblasts. 3. Biochemical analyses determined that the major part of mitogen released from aortic endothelial cells of both SHRSP and controls was the platelet-derived growth factor B-chain. 4. Further northern analyses revealed that the transcripts of PDGF B-chain were constitutively accumulated three- to four-fold in quiescent aortic endothelial cells from SHRSP, compared with those from WKY through passages 2 to 5. 5. However, the half-lives of the transcripts after actinomycin D treatment were 1.12 h (s.d. = 0.14, n = 4) and 1.28 h (s.d. = 0.08, n = 3), in SHRSP and in WKY, respectively, showing no significant difference. 6. These suggest that the increased accumulated transcripts of PDGF B-chain in SHRSP are due to an enhanced transcriptional rate. These enhanced release and production of PDGF-B chain in arterial endothelial cells, which may be induced under chronic hypertensive conditions, is suggested to contribute to the genesis of vascular lesion in hypertension, through the stimulation of vascular smooth muscle cell proliferation and hypertrophy.
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PMID:Platelet-derived growth factor B-chain comprises the major part of enhanced released mitogen from aortic endothelial cells of stroke-prone spontaneously hypertensive rats. 907 22

In this review, the role of tyrosine kinases in angiotensin II-mediated signal transduction pathways in vascular smooth muscle is discussed. Angiotensin II was isolated by virtue of its vasoconstrictor abilities and has long been thought to play a critical role in hypertension. However, recent studies indicate important roles for angiotensin II in inflammation, atherosclerosis, and congestive heart failure. The expanding role of angiotensin II indicates that multiple signal transduction pathways are likely to be activated in a tissue-specific manner. Exciting recent data show that angiotensin II directly stimulates tyrosine kinases, including pp60(c-src) kinase (c-Src), focal adhesion kinase (FAK), and Janus kinases (JAK2 and TYK2). Angiotensin II may activate receptor tyrosine kinases, such as Axl and platelet-derived growth factor, by as-yet-undefined autocrine mechanisms. Finally, unknown tyrosine kinases may mediate tyrosine phosphorylation of Shc, Raf, and phospholipase C-gamma after angiotensin II stimulation. These angiotensin II-regulated tyrosine kinases appear to be required for angiotensin II effects, such as vasoconstriction, proto-oncogene expression, and protein synthesis, on the basis of studies with tyrosine kinase inhibitors. Thus, understanding angiotensin II-stimulated signaling events, especially those related to tyrosine kinase activity, may form the basis for the development of new therapies for cardiovascular diseases.
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PMID:Angiotensin II signal transduction in vascular smooth muscle: role of tyrosine kinases. 913 Apr 41

Vascular smooth muscle cells (VSMC) contribute to the pathophysiology of hypertension through cell growth and contraction, and phospholipase C (PLC) is a critical effector enzyme in growth factor and vasoconstrictor signaling. There is indirect evidence that angiotensin II (ANG II) receptors are linked to the PLC-beta isoform signaling pathways. However, recent studies suggest that PLC-beta isoforms may not be expressed in VSMC. Our data demonstrate that in human aortic VSMC, PLC-beta 1 and PLC-gamma 1 proteins were detected by immunoblot analysis, and PLC-beta 1 mRNA was identified by reverse transcriptase-polymerase chain reaction in rat aortic VSMC. Incubation of permeabilized VSMC with anti-PLC-beta 1 or anti-Gq alpha antibodies inhibited ANG II-dependent inositol polyphosphate (IP) formation, while anti-PLC-gamma 1 antibodies did not inhibit ANG II-regulated IP formation. Conversely, anti-PLC-gamma 1 antibodies completely abolished platelet-derived growth factor (PDGF)-dependent IP generation, whereas anti-PLC-beta 1 antibodies had no effect on PDGF-induced PLC activation. Inhibition of tyrosine phosphorylation with genistein or herbimycin A did not diminish ANG II-stimulated IP formation or cytosolic free Ca2+ concentration transients, thereby confirming that ANG II signals via a PLC-gamma 1-independent mechanism. In summary, PLC-beta 1 and PLC-gamma 1 are expressed in human aortic VSMC, and PLC-beta 1 is the isoform that is critical for ANG II-regulated PLC signaling in these cells.
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PMID:Angiotensin II activates the beta 1 isoform of phospholipase C in vascular smooth muscle cells. 917 47

Vascular smooth muscle cells of rat aorta express imidazoline receptors whose stimulation, by drugs or an endogenous ligand, agmatine, inhibits serum-stimulated proliferation. We investigated whether imidazoline receptors are expressed in human vascular smooth muscle cells if their stimulation is antiproliferative. Cultured human coronary artery vascular smooth muscle cells express a nonadrenergic binding site for 3H-idazoxan and an imidazoline receptor-binding protein as revealed by immunocytochemical and immunoblot analyses with a specific antibody. Idazoxan and agmatine dose-dependently inhibited serum-stimulated proliferation of these cells as measured by the incorporation of 3H-thymidine (IC50: 5 and 70 micromol/L, respectively) and serum-stimulated expression of proliferating cell nuclear antigen and cell numbers. The agents inhibited proliferation of human and rat (aorta) smooth muscle cells stimulated by either norepinephrine (6560+/-440 disintegrations per minute norepinephrine versus 3345+/-220 norepinephrine and idazoxan), angiotensin II (7680+/-335 disintegrations per minute angiotensin II versus 3769+/-450 angiotensin II and idazoxan), or platelet-derived growth factor (IC50: 3 micromol/L for idazoxan and 40 micromol/L for agmatine), indicating inhibition of mitosis mediated by G-protein or receptor tyrosine kinase pathways. We conclude that human vascular smooth muscle cells express imidazoline-receptors whose activation inhibits proliferation by interacting at a distal step in an intracellular signal cascade common to G-protein and receptor tyrosine kinase mitogenic pathways. Agmatine, synthesized in endothelium, may act as a paracrine regulator of vascular smooth muscle cell proliferation through imidazoline receptors, and agents acting at this site may be useful in treating vascular hyperplasia.
Hypertension 1997 Aug
PMID:Stimulation of imidazoline receptors inhibits proliferation of human coronary artery vascular smooth muscle cells. 926 Sep 95

Atrial natriuretic peptide (ANP) regulates a variety of physiological parameters, including the blood pressure and intravascular volume, by interacting with its receptors present on the plasma membrane. ANP receptors are of three subtypes: ANP-A, -B and -C receptors. ANP-A and ANP-B receptors are guanylyl cyclase receptors, whereas ANP-C receptors are coupled to adenylyl cyclase inhibition or phospholipase C activation through inhibitory guanine nucleotide-regulating protein. Unlike other G protein-coupled receptors, ANP-C receptors have a single transmembrane domain and a short cytoplasmic domain of 37 amino acids, the cytoplasmic domain has a structural specificity like those of other single-transmembrane-domain receptors and 37 amino-acid cytoplasmic domain peptide is able to exert is inhibitory effect on adenylyl cyclase. The activation of ANP-C receptor by C-ANP(4-23) (a ring-deleted peptide of ANP) and C-type natriuretic peptide inhibits the mitogen-activated protein kinase activity stimulated by endothelin-3, platelet-derived growth factor and phorbol-12 myristate 13-acetate. C-ANP also inhibits mitogen-induced stimulation of DNA synthesis, indicating that the ANP-C receptor plays a role in cell proliferation through an inhibition of mitogen-activated protein kinase and suggesting that the ANP-C receptor might also be coupled to other signal transduction mechanism(s) or that there might be an interaction of the ANP-C receptor with some other signalling pathways. ANP receptor binding is decreased in most organs in hypertensive subjects and hypertensive animals. This decrease is consistent with there being fewer guanylyl cyclase-coupled receptors in the kidney and vasculature and selective inhibition of the ANP-C receptor in the thymus and spleen. Platelet ANP-C receptors are decreased in number in hypertensive patients and spontaneously hypertensive rats. ANP-A, -B and -C receptors are decreased in number in deoxycorticosterone acetate-salt-treated kidneys and vasculature; however, the responsiveness of adenylyl cyclase to ANP is augmented in the vasculature and heart and is attenuated completely in platelets. These alterations in ANP receptor subtypes may be related to the pathophysiology of hypertension. Several hormones such as angiotensin II, ANP and catecholamines, the levels of which are increased in hypertension, downregulate or upregulate ANP-C receptors and ANP-C receptor-mediated inhibition of adenylyl cyclase. It can be suggested that the antihypertensive action of several types of drugs such as angiotensin converting enzyme inhibitors, angiotensin type 1 receptor antagonists and beta2-adrenergic antagonists may partly be attributed to their ability to modulate the expression and function of the ANP-C receptor.
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PMID:Atrial natriuretic peptide-C receptor and membrane signalling in hypertension. 928 Feb 3

Increasing evidence suggests that cytokines such as interleukin-1beta (IL-1), IL-4, and IL-8 may play an important role in the chronic inflammation and cellular growth observed in cardiovascular diseases. The lipoxygenase (LO) pathway of arachidonate metabolism has also been related to the pathology of hypertension and atherosclerosis. LO products have chemotactic, hypertrophic, and mitogenic effects in vascular cells, and the LO enzyme has been implicated in the oxidation of LDL. Furthermore, earlier studies have shown that vascular smooth muscle cell (VSMC) growth factors such as angiotensin II and platelet-derived growth factor can increase LO activity and expression in VSMCs. In the present study, we have examined whether vasoactive and inflammatory cytokines such as IL-1, IL-4, and IL-8 can modulate 12-LO activity and expression in porcine VSMCs and also whether they have growth-promoting effects in these cells. Treatment of porcine VSMCs with these cytokines led to significant increases in the levels of a cell-associated 12-LO product, 12-hydroxyeicosatetraenoic acid, as well as intracellular 12-LO enzyme activity. Furthermore, each of these cytokines led to a dose-dependent increase in 12-LO mRNA expression (333-base pair PCR product) as well as 12-LO protein expression (72 kD). In addition, all three interleukins could induce significant increases in VSMC DNA synthesis as well as proliferation. These results suggest that these cytokines have mitogenic effects in VSMCs and are also potent positive regulators of the 12-LO pathway. Thus, enhanced 12-LO activity and expression may be a key mechanism for cytokine-induced VSMC migration and proliferation.
Hypertension 1997 Oct
PMID:Regulation of 12-lipoxygenase by cytokines in vascular smooth muscle cells. 933 87

Migration of vascular smooth muscle cells (SMC) constitutes a common step in neointimal formation which occurs in several vascular diseases. Whether the migratory response of SMC derived from hypertensive animals is different to that of controls may provide a clue to the link between hypertension and atherosclerosis. We examined the migratory responses of SMC from cell cultures and ring explants (thin aortic ring segment) and compared these responses between normotensive and hypertensive rats at two different ages. Both scrape-wound assay and transwell chambers from cultured aortic SMC as well as aortic ring explant cell outgrowth models were employed. The aortae were obtained from male spontaneously hypertensive rats (SHR) and their normotensive counterpart the Wistar-Kyoto rat (WKY) at 5 and 20 weeks of age. Migration was induced by fetal bovine serum or platelet-derived growth factor (PDGF) and migrated cells were counted at different times following stimulation. We found that SMC migration exhibited a high sensitivity to serum (range of ED50: 2.2-3.6%), migration of SMC from 20-week-old SHR exceeded (by 46%, P<0.025) that of SMC from age-matched WKY and the difference became significant as early as 8 h after stimulation by serum. Chemotaxis induced by PDGF (2 h) exhibited similar differences. An elevated migratory response in SHR-SMC was also found in cells derived from 5-week-old rats in whom the blood pressure was normal. In younger animals, cell outgrowth from SHR aortic ring explants also accumulated more cells compared with WKY without a higher growth rate, thus suggesting that SHR-SMC have a higher migratory response ex vivo. In conclusion, aortic SMC migration appeared to be enhanced in various preparations from SHR. This difference also existed in young animals before the elevation of blood pressure occurred and might contribute partly to the role of hypertension as a risk factor for atherosclerosis.
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PMID:Migration of vascular smooth muscle cells is enhanced in cultures derived from spontaneously hypertensive rat. 938 44

Intracellular Ca2+ and pH are potent modulators of growth factor-induced mitogenesis and contraction. This study examined platelet-derived growth factor-(PDGF-BB) and insulin-like growth factor (IGF-1)-mediated signal transduction in primary cultured unpassaged vascular smooth muscle cells (VSMC) from mesenteric arteries of Sprague-Dawley rats. Intracellular free Ca2+ concentration ([Ca2+]i) and intracellular pH (pHi) were measured by fluorescence digital imaging using fura-2 AM and 2'7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, respectively. Characteristics of [Ca2+]i transients were determined by pre-exposing cells to Ca2+-free buffer, and involvement of the Na+/Ca2+ exchanger was assessed by withdrawal of extracellular Na+ and by exposure to dimethylbenzamil (Na+/Ca2+ exchange blocker). To determine whether pHi responses were mediated via the Na+/H+ exchanger, cells were preincubated with 10(-5) mol/L 5-(N-ethyl-N-isopropyl)amiloride (a selective Na+/H+ exchange blocker). The role of protein kinase C (PKC) and tyrosine kinases in growth factor signaling was assessed by pre-exposing cells to calphostin C and chelerythrine chloride (selective PKC inhibitors; 10(-5) mol/L) and tyrphostin A23 (a selective tyrosine kinase inhibitor; 10(-5) mol/L). PDGF-BB and IGF-1 (1 to 10 ng/mL) increased [Ca2+]i and pHi in a dose-dependent manner. At concentrations greater than 1 ng/mL both growth factors induced a biphasic [Ca2+]i response with an initial transient peak followed by a sustained elevation. At 5 ng/mL PDGF-BB and IGF-1 significantly increased [Ca2+]i from 95+/-3 nmol/L to 328+/-28 and 251+/-18 nmol/L, respectively. Ca2+ withdrawal abolished the second phase of [Ca2+]i elevation. Agonist-induced [Ca2+]i responses were similarly altered by Na+ withdrawal, by Na+/ Ca2+ exchange blockade, and by PKC inhibition; latency, the period from stimulus application to the first [Ca2+]i peak, was increased, the initial [Ca2+]i peak was attenuated, and the sustained phase was prolonged. PDGF-BB and IGF-1 (10 ng/mL) significantly increased pHi from 6.89+/-0.04 nmol/L to 7.11+/-0.01 and 7.09+/-0.02 nmol/L, respectively. EIPA and calphostin C completely inhibited agonist-elicited alkalinization. Tyrphostin A-23 abolished second-messenger responses to PDGF-BB and IGF-1, whose receptors have tyrosine kinase activity. In conclusion, PDGF-BB and IGF-1 elicit significant [Ca2+]i and pHi responses in VSMC. The underlying pathways that mediate these responses are partially dependent on Na+/ Ca2+ transporters and the Na+/H+ exchanger, both of which are linked to PKC activation.
Hypertension 1997 Dec
PMID:Growth factors mediate intracellular signaling in vascular smooth muscle cells through protein kinase C-linked pathways. 940 65


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