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

Phosphatidylinositol 3-kinase (PI3K) activity is increased in aortae from deoxycorticosterone (DOCA)-salt rats and enhanced PI3K activity contributes to the arterial hyperreactivity in these animals. Because PI3K activity is increased in DOCA-salt hypertension, we postulated that phosphorylation of Akt and glycogen synthase kinase 3 (GSK-3), serine threonine kinases that are downstream of PI3K, would be increased in DOCA-salt hypertension. In this study, we focused on GSK-3. Because GSK-3 activity is reduced by phosphorylation, we expected that its activity would be reduced in DOCA-salt hypertensive arteries and that reduced GSK-3 activity could contribute to enhanced adrenergic signaling and vascular smooth muscle hypertrophy that augment the heightened contractile response in DOCA-salt hypertension. Surprisingly, we observed a decrease in phosphorylation of GSK-3, indicating an increase in GSK-3 activity. To determine whether increased GSK-3 activity contributes to altered arterial reactivity in DOCA-salt animals, we measured isometric contraction to norepinephrine (NE) in the presence and absence of PI3K or GSK-3 inhibition. Addition of LY294002 (20 micromol/L), a PI3K inhibitor, resulted in a rightward shift in response to NE and normalized the NE-induced contractions in the DOCA hypertensive vessels. SB415286, a GSK-3 inhibitor, resulted in a slight rightward shift in response to NE in the DOCA-salt vessels. Thus, enhanced GSK-3 activity modestly augments the effects of PI3K but does not appear to contribute greatly to the altered arterial reactivity in DOCA-salt hypertension.
Hypertension 2003 Apr
PMID:PI3-kinase-induced hyperreactivity in DOCA-salt hypertension is independent of GSK-3 activity. 1262 35

Lipocalin-type prostaglandin D2 synthase (L-PGDS) has recently been linked to a variety of pathophysiological cardiovascular conditions including hypertension and diabetes. In this study, we report on the 50% increase in L-PGDS protein expression observed in vascular smooth muscle cells (VSMC) isolated from spontaneously hypertensive rats (SHR). L-PGDS expression also increased 50% upon the differentiation of normotensive control cells (WKY, from Wistar-Kyoto rats). In addition, we demonstrate differential effects of L-PGDS treatment on cell proliferation and apoptosis in VSMCs isolated from SHR versus WKY controls. L-PGDS (50 microg/ml) was able to significantly inhibit VSMC proliferation and DNA synthesis and induce the apoptotic genes bax, bcl-x, and ei24 in SHR but had no effect on WKY cells. Hyperglycemic conditions also had opposite effects, in which increased glucose concentrations (20 mm) resulted in decreased L-PGDS expression in control cells but actually stimulated L-PGDS expression in SHR. Furthermore, we examined the effect of L-PGDS incubation on insulin-stimulated Akt, glycogen synthase kinase-3beta (GSK-3beta), and ERK phosphorylation. Unexpectedly, we found that when WKY cells were pretreated with L-PGDS, insulin could actually induce apoptosis and failed to stimulate Akt/GSK-3beta phosphorylation. Insulin-stimulated ERK phosphorylation was unaffected by L-PGDS pretreatment in both cell lines. We propose that L-PGDS is involved in the balance of VSMC proliferation and apoptosis and in the increased expression observed in the hypertensive state is an attempt to maintain a proper equilibrium between the two processes via the induction of apoptosis and inhibition of cell proliferation.
 ...
PMID:Prostaglandin D2 synthase inhibits the exaggerated growth phenotype of spontaneously hypertensive rat vascular smooth muscle cells. 1268 6

Adrenomedullin (AM) is a potent vasoactive peptide and plays an important role in cardiovascular function. In this study, we delivered the AM gene locally into the heart, using a catheter-based technique to investigate the signaling mechanism mediated by AM in protection against cardiomyocyte apoptosis induced by acute ischemia/reperfusion. After adenovirus-mediated gene delivery, highly efficient and specific expression of luciferase, green fluorescent protein, or recombinant human AM was identified in the left ventricle. Delivery of the AM gene 5 days before ischemia/reperfusion attenuated myocardial apoptosis identified by in situ dUTP nick-end labeling and DNA laddering, and the effect was blocked by the AM antagonist human calcitonin gene-related peptide (CGRP 8 to 37). AM gene transfer increased phosphorylation of Akt and glycogen synthase kinase (GSK-3beta) but reduced GSK-3beta and caspase-3 activities in the heart. The effects of AM on GSK-3beta and caspase-3 activities were blocked by CGRP (8-37) and by adenovirus containing dominant-negative Akt (DN-Akt). Furthermore, in cultured cardiomyocytes, AM also attenuated apoptosis induced by hypoxia/reoxygenation, which was accompanied by increased phospho-GSK-3beta but reduced GSK-3 and caspase-3 activities. GSK-3 and caspase-3 activities were both blocked by Ad.DN-Akt and lithium, whereas only caspase-3 was inhibited by its inhibitor Z-VAD. The effects of AM on anti-apoptosis and promoting cell viability were blocked by DN-Akt but not by constitutively active Akt, lithium, or Z-VAD. These results indicate that AM protects against cardiomyocyte apoptosis induced by ischemia/reperfusion injury through the Akt-GSK-caspase signaling pathway.
Hypertension 2004 Jan
PMID:Adrenomedullin protects against myocardial apoptosis after ischemia/reperfusion through activation of Akt-GSK signaling. 1466 48

Because adverse effects of glucose were attributed to its increased routing through the hexosamine pathway (HBP), we inquired whether HBP activation affects pancreatic beta-cell survival. Exposure of human islets to high glucose resulted in increased apoptosis of beta-cells upon serum deprivation that was reversed by azaserine. Also, glucosamine, a direct precursor of the downstream product of the HBP, increased human beta-cells apoptosis upon serum deprivation, which was reversed by benzyl-2-acetamido-2-deoxy-alpha-d-galactopyranoside (BADGP), an inhibitor of protein O-glycosylation. These results were reproduced in RIN rat beta-cells. Glucosamine treatment resulted in inhibition of tyrosine-phosphorylation of the insulin receptor (IR), IRS-1, and IRS-2, which was associated with increased O-glycosylation. These changes caused impaired activation of the PI 3-kinase/Akt survival signaling that resulted in reduced GSK-3 and FOXO1a inactivation. BADGP reversed the glucosamine-induced reduction in insulin-stimulated phosphorylation of IR, IRS-1, IRS-2, Akt, GSK-3, and FOXO1a. Impaired FOXO1a inactivation sustained expression of the pro-apoptotic protein Bim, without affecting Bad, Bcl-XL, or Bcl-2 expression. These results indicate that hyperglycemia may increase susceptibility to apoptosis of human and rat beta-cell through activation of the HBP. Increased routing of glucose through this metabolic pathway results in impaired activation of the IR/IRSs/PI3-kinase/Akt survival pathway by induction of O-glycosylation of signaling molecules.
 ...
PMID:Increased O-glycosylation of insulin signaling proteins results in their impaired activation and enhanced susceptibility to apoptosis in pancreatic beta-cells. 1505 79

Phosphoinositide-3 kinases (PI3Ks) are a family of evolutionary conserved lipid kinases that mediate many cellular responses in both physiologic and pathophysiologic states. Class I PI3K can be activated by either receptor tyrosine kinase (RTK)/cytokine receptor activation (class I(A)) or G-protein-coupled receptors (GPCR) (class I(B)). Once activated PI3Ks generate phosphatidylinositols (PtdIns) (3,4,5)P(3) leading to the recruitment and activation of Akt/protein kinase B (PKB), PDK1 and monomeric G-proteins (e.g. Rac-GTPases), which then activate a range of downstream targets including glycogen synthase kinase-3beta (GSK-3beta), mammalian target of rapamycin (mTOR), p70S6 kinase, endothelial nitric oxide synthase (eNOS) and several anti-apoptotic effectors. Class I(A) (PI3Kalpha, beta and delta) and class I(B) (PI3Kgamma) PI3Ks mediate distinct phenotypes in the heart and under negative control by the 3'-lipid phosphatase, phosphatase and tensin homolog on chromosome ten (PTEN) which dephosphorylate PtdIns(3,4,5)P(3) into PtdIns(4,5)P(2). PI3Kalpha, gamma and PTEN are expressed in cardiomyocytes, fibroblasts, endothelial cells and vascular smooth muscle cells where they modulate cell survival/apoptosis, hypertrophy, contractility, metabolism and mechanotransduction. Several transgenic and knockout models support a fundamental role of PI3K/PTEN signaling in the regulation of myocardial contractility and hypertrophy. Consequently the PI3K/PTEN signaling pathways are involved in a wide variety of diseases including cardiac hypertrophy, heart failure, preconditioning and hypertension. In this review, we discuss the biochemistry and molecular biology of PI3K (class I isoforms) and PTEN and their critical role in cardiovascular physiology and diseases.
 ...
PMID:The role of phosphoinositide-3 kinase and PTEN in cardiovascular physiology and disease. 1527 15

Osteopontin (OPN) expression increases in the heart during hypertrophy and heart failure. Here, we studied the role of OPN in pressure overload-induced hypertrophy and analyzed the signaling pathways involved in hypertrophy. Aortic banding (AB) was performed in a group of wild-type (WT) and OPN knockout (KO) mice to induce pressure overload. Left ventricular (LV) structural and functional remodeling was studied 1 month after AB. AB increased OPN and beta1 integrin (a receptor for OPN) protein expression in WT-AB group. Hypertrophic response as measured by increased heart weight-to-body weight ratio and myocyte cross-sectional area was significantly increased in WT-AB and KO-AB groups when compared with their respective shams. However, the increase was significantly higher in WT-AB. Re-expression of atrial natriuretic factor was only detected in WT-AB group. LV end-diastolic pressure-volume curve obtained using Langendorff perfusion analysis exhibited a leftward shift in WT-AB group, not in KO-AB. LV-developed pressures measured over a range of LV volumes were significantly increased in WT-AB, not in KO-AB mice. Increased phosphorylation of c-Jun N-terminal kinases, p38 kinase, Akt, and glycogen synthase kinase-3beta was significantly higher in WT-AB when compared with KO-AB group. Increased OPN expression may play an essential role in modulating compensatory cardiac hypertrophy in response to chronic pressure overload.
Hypertension 2004 Dec
PMID:Osteopontin modulates myocardial hypertrophy in response to chronic pressure overload in mice. 1552 Feb 99

Essential hypertension is frequently associated with insulin resistance of skeletal muscle glucose transport, with a potential role of angiotensin II in the pathogenesis of both conditions. The male heterozygous TG(mREN2)27 rat harbors the mouse transgene for renin, exhibits local elevations in angiotensin II, and is an excellent model of both hypertension and insulin resistance. The present study was designed to investigate the potential cellular mechanisms for insulin resistance in this hypertensive animal model, including an assessment of elements of the insulin-signaling pathway. Compared with nontransgenic, normotensive Sprague-Dawley control rats, male heterozygous TG(mREN2)27 rats displayed elevated (P < 0.05) fasting plasma insulin (74%), an exaggerated insulin response (108%) during an oral glucose tolerance test, and reduced whole body insulin sensitivity. TG(mREN2)27 rats also exhibited decreased insulin-mediated glucose transport and glycogen synthase activation in both the type IIb epitrochlearis (30 and 46%) and type I soleus (22 and 64%) muscles. Importantly, there were significant reductions (approximately 30-50%) in insulin stimulation of tyrosine phosphorylation of the insulin receptor beta-subunit and insulin receptor substrate-1 (IRS-1), IRS-1 associated with the p85 subunit of phosphatidylinositol 3-kinase, Akt Ser473 phosphorylation, and Ser9 phosphorylation of glycogen synthase kinase-3beta in epitrochlearis and soleus muscles of TG(mREN2)27 rats. Soleus muscle triglyceride concentration was 25% greater in the transgenic group compared with nontransgenic animals. Collectively, these data provide the first evidence that the insulin resistance of the hypertensive male heterozygous TG(mREN2)27 rat can be attributed to specific defects in the insulin-signaling pathway in skeletal muscle.
 ...
PMID:Defective insulin signaling in skeletal muscle of the hypertensive TG(mREN2)27 rat. 1565 91

Male heterozygous TG(mREN2)27 rats (TGR) overexpress a murine renin transgene, display marked hypertension, and have insulin resistance of skeletal muscle glucose transport and insulin signaling. We have shown previously that voluntary exercise training by TGR improves insulin-mediated skeletal muscle glucose transport (Kinnick TR, Youngblood EB, O'Keefe MP, Saengsirisuwan V, Teachey MK, and Henriksen EJ. J Appl Physiol 93: 805-812, 2002). The present study evaluated whether this training-induced enhancement of muscle glucose transport is associated with upregulation of critical insulin signaling elements, including insulin receptor substrate-1 (IRS-1), phosphatidylinositol 3-kinase, Akt, and glycogen synthase kinase-3. TGR remained sedentary or ran spontaneously in activity wheels for 6 wk, averaging 7.1 +/- 0.8 km/day by the end of week 3 and 4.3 +/- 0.5 km/day over the final week of training. Exercise training reduced total abdominal fat by 20% (P < 0.05) in TGR runners (2.64 +/- 0.01% of body weight) compared with sedentary TGR controls (3.28 +/- 0.01%). Insulin-stimulated (2 mU/ml) glucose transport activity in soleus muscle was 36% greater in TGR runners compared with sedentary TGR controls. However, the protein expression and functionality of tyrosine phosphorylation of insulin receptor and IRS-1, IRS-1 associated with the p85 regulatory subunit of phosphatidylinositol 3-kinase, and Ser473 phosphorylation of Akt were not altered by exercise training. Only insulin-stimulated glycogen synthase kinase-3beta Ser9 phosphorylation was increased (22%) by exercise training. These results indicate that voluntary exercise training in TGR can enhance insulin-mediated glucose transport in skeletal muscle, as well as reduce total abdominal fat mass. However, this adaptive response in muscle occurs independently of modifications in the proximal elements of the insulin signaling cascade.
 ...
PMID:Voluntary exercise training enhances glucose transport but not insulin signaling capacity in muscle of hypertensive TG(mREN2)27 rats. 1571 10

Several opinion leaders have monitored their blood pressure systematically a sufficient number of times a day for chronomic (time structural) analyses, from the time of encountering chronobiology until their death; they set an example for others who also may not wish to base treatment on single spotchecks in a health care office. Such self-measurements, while extremely helpful, were not readily feasible without a noteworthy interruption of activities during waking as well as of sleep. New, relatively unobtrusive instrumentation now makes monitoring possible and cost-effective and will save lives. Illustrative results and problems encountered in an as-one-goes self-survey by GSK, a physician-scientist, are presented herein. Both MESOR-hypertension and CHAT (circadian hyper-amplitude-tension) can be intermittent conditions even under treatment, and treatment is best adjusted based on monitoring, rather than "flying blind".
 ...
PMID:Why continued surveillance? Intermittent blood pressure and heart rate abnormality under treatment. 1627 83

Kallikrein cleaves low molecular weight kininogen to generate vasoactive kinins, which bind to the kinin B2 receptor, triggering a host of biological effects. Kallikrein gene delivery has been shown previously to reduce ischemia/reperfusion-induced cerebral infarction. In this study, we tested the hypothesis that the kinin B2 receptor plays a protective role in ischemic brain injury using kinin B2 receptor gene knockout (B2R-KO) mice subjected to middle cerebral artery occlusion (MCAO). The mortality rate and neurological deficit scores of B2R-KO mice (n=48) after MCAO were significantly increased compared with wild-type (WT) mice (n=40) when examined over a 14-day period. In addition, the infarct volume in B2R-KO mice was significantly larger than in WT mice at days 1 and 3 after MCAO. Similarly, apoptotic cells, detected by TUNEL labeling counterstained with propidium iodide, and caspase-3 activity in the ischemic brain increased significantly in B2R-KO mice at days 1 and 3 after MCAO. Furthermore, the accumulation of neutrophils in the ischemic brain of B2R-KO mice after MCAO increased when compared with WT mice and was associated with elevated tumor necrosis factor alpha expression. These alterations in B2R-KO mice correlated with decreased NO levels, Akt, and glycogen synthase kinase-3beta phosphorylation and increased nicotinamide-adenine dinucleotide oxidase activity. These results indicate that the kinin B2 receptor promotes survival and protects against brain injury by suppression of apoptosis and inflammation induced by ischemic stroke.
Hypertension 2006 Apr
PMID:Postischemic brain injury is exacerbated in mice lacking the kinin B2 receptor. 1839 Oct 96


1 2 3 Next >>