Quinapril inhibits c-Myc expression and normalizes smooth muscle cell proliferation in spontaneously hypertensive rats

Pathologic HDAC1/c-Myc signaling axis is responsible for angiotensinogen transcription and hypertension induced by high-fat diet

High-fat diet (HFD)-induced obesity is a cause of resistant hypertension. We have shown a possible link between histone deacetylases (HDACs) and renal angiotensinogen (Agt) upregulation in the HFD-induced hypertension, whereas the underlying mechanisms remain to be elucidated. Here, using a HDAC1/2 inhibitor romidepsin (FK228) and siRNAs, we determined roles of HDAC1 and HDAC2 in HFD-induced hypertension and found the pathologic signaling axis between HDAC1 and Agt transcription. Treatment with FK228 canceled the increased blood pressure of male C57BL/6 mice induced by HFD. FK228 also blocked upregulation of renal Agt mRNA, protein, angiotensin II (Ang II) or serum Ang II. Activation and nuclear accumulation of both HDAC1 and HDAC2 occurred in the HFD group. The HFD-induced HDAC activation was associated with an increase in deacetylated c-Myc transcription factor. Silencing of HDAC1, HDAC2 or c-Myc in HRPTEpi cells decreased Agt expression. However, only HDAC1 knockdown, but not HDAC2, increased c-Myc acetylation, suggesting selective roles in two enzymes. Chromatin immunoprecipitation assay revealed that HFD induced the binding of HDAC1 and deacetylated c-Myc at the Agt gene promoter. A putative c-Myc binding sequence in the promotor region was necessary for Agt transcription. Inhibition of c-Myc downregulated Agt and Ang II levels in kidney and serum, ameliorating HFD-induced hypertension. Thus, the abnormal HDAC1/2 in the kidney may be responsible for the upregulation of the Agt gene expression and hypertension. The results expose the pathologic HDAC1/c-myc signaling axis in kidney as a promising therapeutic target for obesity-associated resistant hypertension.

The roles of Qishen granules recipes, Qingre Jiedu, Wenyang Yiqi and Huo Xue, in the treatment of heart failure

ETHNOPHARMACOLOGICAL RELEVANCE

Recipes (Qingre Jiedu (QJ), Wenyang Yiqi (WYYQ) and Huo Xue (HX)) in Qishen granules (QSG) are believed to synergistically exert cardio-protective effects. However, the underlying pattern of each decomposed recipe in QSG and their synergistic effects in the treatment of heart failure (HF) are not clear.

OBJECTIVE

The purpose of this study is to explore the biological contributions of decomposed recipes to therapeutic effects of QSG and reveal the pharmacological mechanism of QSG in treating HF.

MATERIALS AND METHODS

The therapeutic effects of QSG or its recipes on heart failure were examined in wet-lab at both transcription and phenotypic level using HF Sprague-Dawley rats. Sequencing and transcriptome analyses were performed using in silico approaches including identification of differentially expressed genes, pathway enrichment and protein-protein interaction network studies. Specially, an optimized in silico quantitative pathway analysis that maximally extracted gene expression information was developed to reveal differentially expressed pathways (DEPs) among various groups, and is publicly available as R package QPA on GitHub (https://github.com/github-gs/QPA). Finally, the HF-related genes predicted using DEP approach were validated by quantitative real-time polymerase chain reaction and western blot.

RESULTS

Multiple key genes and the associated signaling pathways were shown to be highly relevant for the therapeutic effect of QSG. Decreased expression of Spp1 gene required for inflammatory signaling and profibrotic signaling were observed in failing hearts treated with QJ, WYYQ and HX. Decreased expression of Cx3cr1 gene required for inflammatory signaling was observed in failing hearts treated with WYYQ and HX. Decreased expression of Myc gene required for oxidative stress and Fgfr2 gene required for profibrotic signaling were observed in failing hearts treated with HX and WYYQ, respectively. Increased expression of Adcy1 gene required for cAMP-PKA signaling cascade was observed in failing hearts treated with WYYQ and HX.

CONCLUSIONS

Our study suggests that QJ, WYYQ and HX recipes in QSG achieve synergistic and complementary therapeutic effects through alleviating inflammatory responses, attenuating ventricular remodeling and enhancing myocardial energy supply.

Functional pathways associated with human carotid atheroma: a proteomics analysis

Advances in large-scale analysis are becoming very useful in understanding health and disease. Here, we used high-throughput mass spectrometry to identify differentially expressed proteins between early and advanced lesions. Carotid endarterectomy samples were collected and dissected into early and advanced atherosclerotic lesion portions. Proteins were extracted and subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Differentially expressed proteins were identified and verified using multiple reaction monitoring (MRM), on which advanced systems biology and enrichment analyses were performed. The identified proteins were further compared to the transcriptomic data of 32 paired samples obtained from early and advanced atherosclerotic lesions. A total of 95 proteins were upregulated, and 117 proteins were downregulated in advanced lesions compared to early atherosclerotic lesions (p < 0.05). The upregulated proteins were associated with proatherogenic processes, whereas downregulated proteins were involved in extracellular matrix organization and vascular smooth muscle cytoskeleton. Many of the identified proteins were linked to various "upstream regulators", among which TGFβ had the highest connections. Specifically, a total of 19 genes were commonly upregulated, and 30 genes were downregulated at the mRNA and protein levels. These genes were involved in vascular smooth muscle cell activity, for which enriched transcription factors were identified. This study deciphers altered pathways in atherosclerosis and identifies upstream regulators that could be candidate targets for treatment.

Angiotensin II increases fibronectin and collagen I through the β-catenin-dependent signaling in mouse collecting duct cells

The contribution of angiotensin II (ANG II) to renal and tubular fibrosis has been widely reported. Recent studies have shown that collecting duct cells can undergo mesenchymal transition suggesting that collecting duct cells are involved in interstitial fibrosis. The Wnt/β-catenin signaling pathway plays an essential role in development, organogenesis, and tissue homeostasis; however, the dysregulation of this pathway has been linked to fibrosis. In this study, we investigated whether AT1 receptor activation induces the expression of fibronectin and collagen I via the β-catenin pathway in mouse collecting duct cell line M-1. ANG II (10(-7) M) treatment in M-1 cells increased mRNA, protein levels of fibronectin and collagen I, the β-catenin target genes (cyclin D1 and c-myc), and the myofibroblast phenotype. These effects were prevented by candesartan, an AT1 receptor blocker. Inhibition of the β-catenin degradation with pyrvinium pamoate (pyr; 10(-9) M) prevented the ANG II-induced expression of fibronectin, collagen I, and β-catenin target genes. ANG II treatment promoted the accumulation of β-catenin protein in a time-dependent manner. Because phosphorylation of glycogen synthase kinase-3β (GSK-3β) inhibits β-catenin degradation, we further evaluated the effects of ANG II and ANG II plus pyr on p-ser9-GSK-3β levels. ANG II-dependent upregulation of β-catenin protein levels was correlated with GSK-3β phosphorylation. These effects were prevented by pyr. Our data indicate that in M-1 collecting duct cells, the β-catenin pathway mediates the stimulation of fibronectin and collagen I in response to AT1 receptor activation.

Therapeutic potential of c-Myc inhibition in the treatment of hypertrophic cardiomyopathy

Investigating the pathophysiological importance of the molecular and mechanical development of cardiomyopathy is critical to find new and broader means of protection against this disease that is increasing in prevalence and impact. The current available treatment options for cardiomyopathy mainly focus on treating symptoms and strive to make the patient more comfortable while preventing progression of disease and sudden death. The proto-oncogene c-Myc (Myc) has been shown to be increased in many different types of heart disease, including hypertrophic cardiomyopathy, before any signs of the disease are present. As the mechanisms of action and multiple pathways of dependent actions of Myc are being dissected by many research groups, inhibition of Myc is becoming an attractive paradigm for prevention and treatment of cardiomyopathy and heart failure. Elucidating the role Myc plays in the development, propagation and perpetuation of cardiomyopathy and heart failure will one day translate into potential therapeutics for cardiomyopathy.

Redox control of the cell cycle in health and disease

The cellular oxidation and reduction (redox) environment is influenced by the production and removal of reactive oxygen species (ROS). In recent years, several reports support the hypothesis that cellular ROS levels could function as ''second messengers'' regulating numerous cellular processes, including proliferation. Periodic oscillations in the cellular redox environment, a redox cycle, regulate cell-cycle progression from quiescence (G(0)) to proliferation (G(1), S, G(2), and M) and back to quiescence. A loss in the redox control of the cell cycle could lead to aberrant proliferation, a hallmark of various human pathologies. This review discusses the literature that supports the concept of a redox cycle controlling the mammalian cell cycle, with an emphasis on how this control relates to proliferative disorders including cancer, wound healing, fibrosis, cardiovascular diseases, diabetes, and neurodegenerative diseases. We hypothesize that reestablishing the redox control of the cell cycle by manipulating the cellular redox environment could improve many aspects of the proliferative disorders.

The effects of quinapril and atorvastatin on artery structure and function in adult spontaneously hypertensive rats

We studied the combined treatment effects of quinapril and atorvastatin on blood pressure and structure and function of resistance arteries from adult spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY rats). Apoptotic cells were identified by in situ end labeling using the terminal deoxynucleotide transferase-mediated dUTP nick end labeling method. Vascular structure was measured using a morphometric protocol and confocal microscopy and a pressurized artery system was used to study vascular functions. We found that a combined treatment with quinapril and atorvastatin lowered systolic blood pressure in both adult SHR and WKY rats and decreased medial thickness and volume and the number of smooth muscle cell layers in mesenteric arteries, as well as media-to-lumen ratio in the interlobular arteries from SHR but not in those from WKY rats. The number of apoptotic smooth muscle cells was higher in the mesenteric arteries from control WKY rats than control SHR and treatment increased the number of apoptotic smooth muscle cells in the arteries from both SHR and WKY rats. Treatment with quinapril and atorvastatin reduced ventricular weight in SHR and normalized the augmented contractile responses to norepinephrine but did not alter the contraction to electric field stimulation. Relaxation responses to acetylcholine and sodium nitroprusside were not affected by the treatment. We conclude that a combined treatment with quinapril and atorvastatin lowered blood pressure and improved cardiac and vessel hypertrophy and vessel function. An increase in apoptotic smooth muscle cells may be one of the mechanisms underlying the structural improvement.

Quinapril effects on resistance artery structure and function in hypertension

The effects of chronic treatment with quinapril on blood pressure, vascular reactivity and structure of resistance arteries were examined in adult, male spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. SHR and WKY at 15 weeks of age were treated with quinapril (10 mg/kg per day) for 10 weeks. Structural changes in the mesenteric arteries were measured by optical sectioning with confocal microscopy and in renal arteries by light microscopic measurements. Apoptotic cells in the mesenteric vessel wall were identified using the terminal deoxynucleotide transferase-mediated dUTP-nick end-labelling (TUNEL) method. The response of mesenteric arteries to noradrenaline, electrical stimulation, acetylcholine and sodium nitroprusside was studied using a pressure myograph system. Treatment with quinapril significantly lowered systolic blood pressure and ventricular weight in both SHR and WKY. It reduced wall thickness and medial volume in mesenteric arteries from SHR and WKY and media-to-lumen ratio in interlobular arteries of SHR. It also decreased the number of smooth muscle layers in SHR and increased the number of apoptotic smooth muscle cells in both SHR and WKY. In addition, treatment normalized the augmented contractile responses and improved the impaired relaxation response of SHR mesenteric arteries to the level of WKY. We conclude that treatment with quinapril lowered blood pressure and improved cardiac and vessel structure and vessel function. An increase in apoptotic process of medial smooth muscle cells is one of the mechanisms underlying the vascular structural improvement.

Pressure alters endothelial effects upon vascular smooth muscle cells by decreasing smooth muscle cell proliferation and increasing smooth muscle cell apoptosis

BACKGROUND

Although de-endothelialization after vascular intervention is associated with intimal hyperplasia, endothelial cells (ECs) increase smooth muscle cell (SMC) numbers in conventional cocultures. In previously published work, SMCs cocultured with ECs in a chronic high-pressure environment exhibited significantly decreased cell counts compared to monocultured SMCs in the same high pressure. This finding contrasted with SMCs cocultured with ECs in ambient pressure, which exhibited significantly higher cell counts than the monocultured SMCs in ambient pressure. We now hypothesize that extracellular pressure decreases SMC number during coculture with ECs by decreasing SMC proliferation through nuclear protein regulation and by increasing SMC apoptosis. Furthermore, this effect depends on the EC response to pressure.

METHODS

Rat aortic SMCs were cultured independently (SMC/0) or cocultured with EC (SMC/EC) under either atmospheric or increased pressure (130-135 mmHg over ambient, SMC/0-P and SMC/EC-P) for 5 days. We assessed SMC proliferative potential by determining c-myc expression (by protein analysis), apoptosis (by cell counting, staining with acridine orange or TUNEL technique), and topoisomerase IIalpha levels. Parallel studies measured the effects of conditioned media from monocultured EC and SMC exposed for 5 days to control or increased pressure on recipient SMC growing in conventional culture.

RESULTS

In high-pressure conditions, SMC/EC-P exhibited 42% less c-myc expression than SMC/0s (P = .00028). Significantly increased apoptotic activity (22 +/- 1.8%) in SMC/EC-Ps compared to SMC/0s was coupled with significantly lower topoisomerase IIalpha levels. Interestingly, pressure (SMC/0-P) and EC coculture (SMC/EC) each separately raised myocyte apoptotic activity to 15 +/- 1.3% and 17 +/- 2.0%, respectively. Conditioned media from pressurized ECs caused a 20% decrease in cell counts in target SMC compared to conditioned media from ECs in atmospheric pressure. Media from pressurized SMCs did not affect target SMCs.

CONCLUSIONS

In a model designed to study SMC/EC interactions in a dynamic environment, EC exposure to pressure alters the growth characteristics and apoptotic activity of SMCs via a secreted factor. Extracellular pressure may alter EC regulation of SMC behavior and regulate intimal hyperplasia.

Long-term effects of quinapril with high affinity for tissue angiotensin-converting enzyme after coronary intervention in Japanese

BACKGROUND

Angiotensin-converting enzyme inhibitors have been shown experimentally to prevent restenosis after balloon injury. We previously reported that quinapril reduced the 6-month restenosis (percent diameter stenosis >or=50%) rate after percutaneous coronary intervention (PCI). However, it was not established whether this favorable outcome was maintained for longer periods.

METHODS

This study was a prospective, randomized, open, and non-placebo controlled trial. Patients with coronary artery disease were enrolled after successful coronary balloon angioplasty or stenting. Two hundred and fifty-three patients were randomly assigned to the quinapril (10-20 mg per day) or control groups. The major clinical end points included death, myocardial infarction, cerebrovascular accident, or revascularization (either coronary artery bypass grafting or repeat PCI). These were tabulated according to the intention-to-treat principle.

RESULTS

Long-term follow-up was available with a median of 4.8 (interquartile range 4.2-5.1) years after the procedure. The incidence of combined end points of mortality and morbidity (myocardial infarction and cerebrovascular accident) in the quinapril group was lower than that in the control group (6.1% vs 14.8%; relative risk [RR] 0.42, 95% CI 0.18-0.96, P =.033). The overall incidence of end-point events in patients with quinapril also occurred less frequently (29.8% vs 46.7%; RR 0.58, 95% CI 0.38-0.86, P =.007).

CONCLUSIONS

These clinical outcomes show that the benefit of quinapril in patients following PCI is maintained for 4 years.

c-Myc oncoprotein: a dual pathogenic role in neoplasia and cardiovascular diseases?

A growing body of evidence indicates that c-Myc can play a pivotal role both in neoplasia and cardiovascular diseases. Indeed, alterations of the basal machinery of the cell and perturbations of c-Myc-dependent signaling network are involved in the pathogenesis of certain cardiovascular disorders. Down-regulation of c-Myc induced by intervention with antioxidants or by antisense technology may protect the integrity of the arterial wall as well as neoplastic tissues. Further intervention studies are necessary to investigate the effects of tissue-specific block of c-Myc overexpression in the development of cardiovascular diseases.

Maintenance of blood pressure control and left ventricular performance with small doses of enalapril

Enalopril treatment (20 mg every 12 hours) of 24 patients with essential hypertension and left ventricular (LV) hypertrophy established normal blood pressure (BP) after 8 weeks, and after 7 years had reduced LV mass index by 39% from 148 +/- 34 to 90 +/- 16 g/m2, and had normalized LV structure and function and QT dispersion. Stepwise reduction of the enalapril dosage from 40 to 30, 20, 10, and 5 mg/day during the eighth year caused no significant changes in BP, LV structure, LV systolic function, or QT dispersion, which all likewise remained unaltered during a further year of the 5-mg/day regimen. We conclude that for hypertensive patients in whom prolonged treatment with standard doses of enalapril has normalized BP, LV structure and function, and QT dispersion, significantly smaller doses are sufficient to maintain these cardiovascular achievements.

Parathyroid hormone-related protein expression in vascular smooth muscle of spontaneously hypertensive rats: evidence for lack of response to angiotensin II

OBJECTIVE

We studied the expression of parathyroid hormone (PTH)-related protein in vascular smooth muscle cells of spontaneously hypertensive rats (SHR) using Wistar-Kyoto (WKY) and Sprague-Dawley rats as normotensive controls.

METHODS

Aortae from 4- and 18-week-old SHR versus age-matched WKY and Sprague-Dawley rats were excised to obtain total RNA or smooth muscle cells. The cells were subcultured in Dulbecco's Modified Eagle's Medium containing 10% fetal calf serum, then serum-deprived for 72 h and stimulated with 0.1 micromol/I angiotensin II. PTH-related protein, c-myc and angiotensin II type qa receptor (AT1aR) messenger (m)RNA levels were measured by Northern blot, using total RNA extracted by phenol/chloroform. The effects of PTH-related protein(1-34)NH2 intravenous injections on arterial blood pressure and the heart rate were studied in anesthetized SHR and WKY rats.

RESULTS

The Northern blots showed a significantly higher abundance of PTH-related protein mRNA in aortae of SHR versus WKY rats in the prehypertensive state but no significant difference in adult animals. In cultured aortic smooth muscle cells, angiotensin II induced a four- to sixfold increase in PTH-related protein mRNA levels in smooth muscle cells from normotensive animals, but failed to elicit a significant response in smooth muscle cells derived from SHR in either the prehypertensive or the hypertensive state. This lack of response to angiotensin II in SHR smooth muscle cells was not due to decreased expression or responsiveness of the AT1aR, since SHR smooth muscle cells had more AT1aR mRNA than Sprague-Dawley smooth muscle cells, and angiotensin II-induced activation of c-myc was faster and greater in smooth muscle cells derived from 4- or 18-week-old SHR than in Sprague-Dawley smooth muscle cells. In contrast, PTH-related protein(1-34)NH2 induced a long-lasting dose-dependent hypotensive and tachycardic response in both SHR and WKY rats, indicating that SHR retained responsiveness to the vasodilator.

CONCLUSIONS

PTH-related protein gene expression in response to angiotensin II is impaired in SHR arteries. A deficiency in this potent local vasodilator may contribute to the development and/or maintenance of arterial hypertension in this model.