Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: UMLS:C0020538 (hypertension)
170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The senescent cell-derived inhibitor (sdi)-1 protein (p21 product) has been identified as a downstream mediator of the tumor suppressor p53 in the regulation of cell cycle progression through a G1 phase checkpoint. Given the importance of cell cycle inhibition for the treatment of restenosis, in this study we focused on the function of p21 gene in inhibiting proliferation of vascular smooth muscle cells (VSMC). To test the hypothesis, we transfected human p21 gene into human aortic VSMC using hemagglutinating virus of Japan-liposome-mediated transfer. Initially, we examined the successful transfection of human p21 gene into VSMC. p21 protein was increased in VSMC transfected with p21 vector as compared with control vector. Accompanied by increased p21 protein, transfection of p21 vector resulted in a significant decrease in number of VSMC induced by 2% serum (P<.01). Although p21 has been reported to play an important role in the regulation of apoptosis in some cells, apoptosis mediated by p21 is still controversial. Therefore, we hypothesized that overexpression of p21 mediates apoptosis in human VSMC, in addition to the blockade of cell cycle progression. First, we assessed the concordance between morphologic analysis and apoptosis as determined by nuclear staining with Hoechst 33342. Cells transfected with p21 gene exhibited the characteristic features of cell shrinkage, membrane blebbing, and rounding that are typical of apoptotic death. Of greater interest, a significant increase in apoptotic cells was observed in VSMC transfected with p21 vector as compared with control vector (P<.01). These results were confirmed by the measurement of DNA fragmentation. Consistent with nuclear staining, DNA fragmentation in VSMC transfected with human p21 gene was significantly increased as compared with that in VSMC transfected with control vector (P<.05). To study the molecular mechanisms of apoptosis mediated by overexpression of p21 gene, the protein levels of bax, a promoter of apoptosis, and bcl-2, an inhibitor of apoptosis, were also measured by Western blotting. Overexpression of p21 gene significantly increased protein of bax (P<.05), whereas transfection of p21 gene did not alter bcl-2 protein. Importantly, the ratio of bax to bcl-2 was significantly increased in VSMC transfected with human p21 vector as compared with control vector (P<.05). Overall, these results demonstrated that inhibition of VSMC growth by overexpression of human p21 gene was accompanied by induction of apoptosis through an inappropriate increase in bax protein. These results suggest that regulation of cell cycle by p21 may be closely linked to programmed cell death/apoptosis in human VSMC.
Hypertension 1998 Jan
PMID:Inhibition of growth of human vascular smooth muscle cells by overexpression of p21 gene through induction of apoptosis. 945 51

Heat shock proteins (HSP) are induced during coronary ischaemia, and abnormal expression of one HSP gene may cause hypertension in rats. We examined association of a promoter polymorphism in the major stress-inducible hsp70 gene (hsp70-1 or HSP70A1) on chromosome 6 (p21.3) with coronary disease traits. This C-->A base substitution (AAACCCC) is at nucleotide position-110 in the heat shock transcription factor binding site (heat shock element, HSE). The first study sample (ECTIM), recruited from Belfast and three centers in France, consisted of 578 myocardial infarction cases and 698 age-matched controls. The frequency of the A-110 allele was 0.381 (95% CI = 0.35-0.41) and 0.384 (95% CI = 0.36-0.41) in cases and controls respectively. Homozygotes for the rarer A-110 allele had a higher BMI (27.3 kg/m2 +/- 3.9) compared with homozygotes for the common C-110 allele (26.3 kg/m2 +/- 3.3). The rarer homozygotes were shorter and heavier than the common homozygotes. A follow-up study involved 1431 healthy, middle aged men from the UK (NPHS II group). The frequency of the A-110 allele was 0.385 (95% CI = 0.37-0.40), and there was no association of genotype with BMI. Thus there appears to be no strong association of the Hsp70-1 promoter polymorphism with risk of myocardial infarction, BMI or any coronary disease traits analysed here.
...
PMID:Analysis of the association of a heat shock protein70-1 gene promoter polymorphism with myocardial infarction and coronary risk traits. 955 37

In cardiac fibroblasts, angiotensin II (Ang II) induced a rapid increase in extracellular signal regulated kinase (ERK) activity in a pertussis toxin insensitive manner. This ERK activation was abolished by the Gq-associated phospholipase C inhibitor U73122 but was insensitive to protein kinase C (PKC) inhibitors or PKC downregulation by phorbol ester. Intracellular Ca2+ chelation by BAPTA-AM or TMB-8 abolished Ang II induced ERK activation, whereas treatment with EGTA or nifedipine did not affect it. Ca2+ ionophore A23187 also induced a rapid increase in ERK activity to an extent similar to that of Ang II stimulation. Calmodulin inhibitors (W7 and calmidazolium) and tyrosine kinase inhibitors (genistein and ST638) completely blocked ERK activation by Ang II and A23187. Both Ang II and A23187 caused a rapid increase in the binding of GTP to p21(Ras), which was nearly abolished by genistein and calmidazolium. Transfection with the dominant negative mutant of Ras and the Ras inhibitor manumycin completely inhibited Ang II induced ERK activation. It was also found for the first time that cardiac fibroblasts abundantly expressed Ca2+-sensitive tyrosine kinase Pyk2/CAKbeta/RAFTK and that Ang II markedly induced its activation in a Ca2+/calmodulin-sensitive manner. Overexpression of the dominant negative mutant of Pyk2 significantly attenuated Ang II or A23187-induced ERK activities (36% and 38% inhibition compared with that in mock-transfected cells, respectively) and ERK tyrosine phosphorylation levels, as well as an increase in the binding of GTP to p21(Ras). These findings demonstrate that in cardiac fibroblasts, Ang II induced Ras/ERK activation is dominantly regulated by Gq-coupled Ca2+/calmodulin signaling and that Pyk2 plays an important role in the signal transmission for efficient activation of the Ang II induced Ras/ERK pathway.
Hypertension 1998 Oct
PMID:Role of calcium-sensitive tyrosine kinase Pyk2/CAKbeta/RAFTK in angiotensin II induced Ras/ERK signaling. 977 61

The growth-promoting effect of mechanical stress on vascular smooth muscle cells (VSMCs) has been implicated in the progress of vascular disease in hypertension. Extracellular signal-regulated kinases (ERKs) have been implicated in cellular responses, such as vascular remodeling, induced by mechanical stretch. However, it remains to be determined how mechanical stretch activates ERKs. The cytoskeleton seems the most likely candidate for force transmission into the interior of the cell. Therefore, we examined (1) whether the cytoskeleton involves mechanical stretch-induced signaling, (2) whether Rho is activated by stretch, and (3) whether Rho mediates the stretch-induced signaling in rat cultured VSMCs. Mechanical stretch activated ERKs, with a peak response observed at 20 minutes, followed by a significant increase in DNA synthesis. Treatment with the ERK kinase-1 inhibitor, PD98059, inhibited the stretch-induced increase in DNA synthesis. Cytochalasin D, which selectively disrupts the network of actin filaments, markedly inhibited stretch-induced ERK activation. In the control state, RhoA was observed predominantly in the cytosolic fraction, but it was translocated in part to the particulate fraction in response to mechanical stretch. Botulinum C3 exoenzyme, which inactivates Rho p21 (known to participate in the reorganization of the actin cytoskeleton), attenuated stretch-induced ERK activation. Inhibition of Rho kinase (p160ROCK) also suppressed stretch-induced ERK activation dose dependently. Our results suggest that mechanotransduction in VSMCs is dependent on intact actin filaments, that Rho is activated by stretch, and that Rho/p160ROCK mediates stretch-induced ERK activation and vascular hyperplasia.
...
PMID:Mechanotransduction of rat aortic vascular smooth muscle cells requires RhoA and intact actin filaments. 1040 Sep 5

Partial renal ablation leads to progressive renal insufficiency and is a model of chronic renal failure from diverse causes. We find that mice develop functional and morphologic characteristics of chronic renal failure after partial renal ablation, including glomerular sclerosis, systemic hypertension, and reduced glomerular filtration. However, we now report that littermates with a homozygous deletion of the gene for the cyclin-dependent kinase inhibitor, p21(WAF1/CIP1), do not develop chronic renal failure after ablation. The markedly different reactions of the p21(+/+) and p21(-/-) animals was not because of differences in glomerular number or degree of renal growth but rather because of the presence or absence of a normal p21 gene. Although the reaction to the stress of renal ablation is both hyperplastic and hypertrophic in the presence of a functional p21 gene, it would appear that the absence of the p21 gene may induce a more hyperplastic reaction because proliferating-cell nuclear antigen expression, a marker of cell-cycle progression, in the renal epithelium of the remnant kidney was more than five times greater in the p21(-/-) mice than in the p21(+/+) animals. Because p21 is a potent inhibitor of the cell cycle, we speculate that p21 regulates the balance between hyperplasia and hypertrophy after renal ablation. We propose that this change in response inhibits the development of chronic renal failure. These studies suggest that controlling p21 function may ameliorate or even prevent progressive end-stage renal disease.
...
PMID:The lack of a functional p21(WAF1/CIP1) gene ameliorates progression to chronic renal failure. 1048 57

Although cAMP is an important second messenger that plays a pivotal role in the regulation of platelet aggregation and dilatation of blood vessels, little is known about the action of cAMP on the growth of vascular smooth muscle cells (VSMCs). Thus, we initially studied the effects of cAMP accumulation by using various cAMP stimulants, including a phosphodiesterase type 3 inhibitor (cilostazol) on human aortic VSMC growth. Accumulation of cAMP inhibited the platelet-derived growth factor (PDGF)-stimulated VSMC growth in a dose-dependent manner (P<0.01), whereas PDGF significantly stimulated the growth of human VSMCs. Thus, we focused on the role of cell cycle regulatory genes, especially on a negative regulator, an anti-oncogene, p53. The protein of p53 was potentiated by cilostazol as well as forskolin and 8-bromo-cAMP, whereas PDGF decreased p53 expression. Upregulation of p53 protein by cAMP was further confirmed by the observation that the decrease in p21, a p53-inducible protein, by PDGF was significantly attenuated by cilostazol in a dose-dependent manner (P<0.01). These results revealed that accumulation of cAMP inhibited VSMC proliferation, which was at least in part due to an increase in p53-p21 expression. Because p53 and p21 have been reported to induce apoptosis, we examined apoptotic cells for cAMP accumulation. Incubation of VSMCs with cilostazol resulted in a significant increase in apoptotic cells in a dose-dependent manner compared with vehicle treatment as assessed by nuclear chromatic morphology (P<0.01); forskolin also stimulated apoptotic cells. Consistent with nuclear staining, DNA fragmentation in VSMCs treated with forskolin as well as 8-bromo-cAMP and cilostazol was significantly increased compared with DNA fragmentation in VSMCs treated with vehicle, whereas PDGF significantly decreased the rate of DNA fragmentation (P<0.01). Overall, these results demonstrated that cAMP inhibited the proliferation of human aortic VSMCs, accompanied by p53-p21-mediated apoptosis. Analogues of cAMP that have direct inhibitory effects on VSMC proliferation can be considered as potential antiproliferative drugs against VSMC growth.
Hypertension 2000 Jan
PMID:Cyclic AMP inhibited proliferation of human aortic vascular smooth muscle cells, accompanied by induction of p53 and p21. 1064 4

Angiotensin II is an important modulator of cell growth through AT(1) receptors, as demonstrated both in vivo and in vitro. We investigated the role of proteins involved in the cell cycle, including cyclin D1, cyclin-dependent kinase 4 (cdk4), and cyclin-dependent kinase inhibitors p21 and p27 in blood vessels of angiotensin II-infused rats and the effect therein of the AT(1)-receptor antagonist losartan. Male Sprague-Dawley rats were infused for 7 days with angiotensin II (120 ng/kg per minute SC) and/or treated with losartan (10 mg/kg per day orally). DNA synthesis in mesenteric arteries was evaluated by radiolabeled (3)H-thymidine incorporation. The expression of cyclin D1, cdk4, p21, and p27, which play critical roles during the G(1)-phase of the cell cycle process, was examined by Western blot analysis. Tail-cuff systolic blood pressure (mm Hg) was elevated (P<0.01, n=9) in angiotensin II-infused rats (161.3+/-8.2) versus control rats (110.1+/-5.3) and normalized by losartan (104.4+/-3.2). Radiolabeled (3)H-thymidine incorporation (cpm/100 microgram DNA) showed that angiotensin II infusion significantly increased DNA synthesis (152+/-5% versus 102+/-6% of control rats, P<0.05). Expression of cyclin D1 and cdk4 was significantly increased in the angiotensin II group to 213.7+/-8% and 263.6+/-37% of control animals, respectively, whereas expression of p21 and p27 was significantly decreased in the angiotensin II group to 23.2+/-10.4% and 10.3+/-5.3% of control animals, respectively. These effects induced by angiotensin II were normalized in the presence of losartan. Thus, when AT(1) receptors are stimulated in vivo, DNA synthesis is enhanced in blood vessels by activation of cyclin D1 and cdk4. Reduction in cell cycle kinase inhibitors p21 and p27 may contribute to activation of growth induced by in vivo AT(1) receptor stimulation.
Hypertension 2001 Feb
PMID:Expression of cell cycle proteins in blood vessels of angiotensin II-infused rats: role of AT(1) receptors. 1123 Mar 42

To investigate whether the genetics of hypertension modifies renal cell responses in experimental diabetes, we studied the renal cell replication and its regulation by two cyclin-dependent kinase (Cdk) inhibitors, p27(Kip1) and p21(Cip1), in prehypertensive spontaneously hypertensive rats (SHR) and their genetically normotensive counterparts, Wistar Kyoto (WKY) rats, with and without streptozotocin-induced diabetes. In diabetic SHR, the number of proliferating glomerular (0.6 +/- 0.3 positive cells/50 glomeruli) and tubulointerstitial (2.8 +/- 0.6 positive tubulointerstitial cells/50 grid fields) cells assessed by the bromodeoxyuridine technique was significantly (P = 0.0002) lower than in control SHR (13.2 +/- 1.7 and 48.6 +/- 9.7, respectively) and control (14.0 +/- 1.8 and 63.9 +/- 10.6) and diabetic (14.3 +/- 3.5 and 66.4 +/- 11.5) WKY rats. Proliferating cell nuclear antigen, another marker of cell proliferation, was significantly reduced in replicating glomerular (P = 0.0002) and tubulointerstitial (P < 0.0001) cells in diabetic SHR. In freshly isolated glomeruli, the level of p27(Kip1) detected by Western blotting was significantly higher in diabetic SHR than in nondiabetic SHR (1.52 +/- 0.14 vs. 1.00 +/- 0.10% of control, P = 0.014). The expression of p21(Cip1) in isolated glomeruli did not differ among the groups of rats. In conclusion, the response of renal cell replication to diabetes differs markedly between prehypertensive SHR and their WKY control rats. The decreased glomerular cell proliferation in prehypertensive diabetic SHR is at least partly mediated by a higher expression of the Cdk inhibitor p27(Kip1).
...
PMID:The genetics of hypertension modifies the renal cell replication response induced by experimental diabetes. 1197 52

Leptin has been hypothesized to be a pathophysiologic link between obesity and cardiovascular diseases. Because the adenylate cyclase (AC) system is a main effector of beta-adrenergic receptors and leptin has been shown to modulate AC activity in other cell lines, a leptin impact on cardiac AC activity was hypothesized. Therefore, acute and chronic effects of leptin on a rat cardiac cell line (H9c2) were investigated. Leptin affected both basal (+ 13% at 30 min and -16.4% after 18 h v untreated cells) and catecholamine-stimulated AC activity (isoproterenol + leptin at 30 min or 18 h was +21% v untreated cells; norepinephrine + leptin at 30 min was +38.8% v untreated cells; and norepinephrine + leptin at 18 h was +6% v untreated cells). Thus, long-term leptin treatment was associated with a reduced AC activity and a different responsiveness to catecholamines. The AC activity on leptin treatment was accompanied by changes in levels of proteins structurally or functionally related to AC complex (AC, Gas, Gai, p21-ras). These data indicate that the AC complex is profoundly affected at more than one level by leptin treatment in the H9c2 cardiac cell line. Differences in AC activity after short- and long-term exposure to leptin and the interaction between leptin and catecholamine might provide further insight to the understanding of the development of hypertension and congestive heart failure in obese patients.
...
PMID:Leptin affects adenylate cyclase activity in H9c2 cardiac cell line: effects of short- and long-term exposure. 1211 13

Vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) proliferate faster than those from Wistar-Kyoto rats (WKY). Therefore regulation of cell cycle progression was examined in VSMC from both strains. Analysis of G1 progression was performed in VSMC synchronized by serum starvation. Double staining for propidium iodide and bromodeoxyuridine revealed that G1 progression was faster in SHR as compared with WKY. Indeed, 59+/-6% of VSMC from SHR but only 14+/-10% of those from WKY had left G1 phase after 24 hours of mitogenic stimulation. Moreover, 15+/-2% of SHR cells had already completed the cycle at this time point. Western blot analysis demonstrated that the level of cyclin D, cyclin E, and cyclin A was higher in SHR cells progressing through G1 phase, whereas expression of cyclin-dependent kinase 2 as well as the cyclin-dependent kinase inhibitors p21 and p27 were similar in the two groups. Consistent with a higher level of cyclins, the activity of cyclin-dependent kinase 2 was more pronounced in SHR cells. Analysis of G2 progression was performed in VSMC synchronized by treatment with aphidicolin and revealed an additional difference in cell cycle regulation between SHR and WKY. Indeed, the level of cell division cycle kinase 2 was higher in cells from SHR, whereas that of its catalytic partner cyclin B was similar. Consistent with this pattern of expression, the activity of cell division cycle kinase 2 was more pronounced in VSMC from SHR as compared with WKY. Thus, these data demonstrate that the different proliferation of VSMC from SHR and WKY is related to a different progression in G1 phase as the result of the expression of cyclin D, cyclin A, and cyclin E as well as a different progression in G2 phase caused by expression of cell division cycle kinase 2.
Hypertension 2003 Aug
PMID:Different cell cycle regulation of vascular smooth muscle in genetic hypertension. 1284 12


1 2 3 4 5 Next >>

---