alpha-chymotrypsin and Hypertension

Human chymase forms angiotenin (ANG) I to ANG II, whereas the roles of ANG II generated by chymase and the effects of chymase inhibitors have been unclear. On the other hand, rat chymase could not convert ANG I to ANG II. In isolated rat arteries, the ANG I-induced vascular contraction was completely suppressed by angiotensin-converting enzyme (ACE) inhibitor only. However, 30% of ANG I-induced vascular contraction in isolated human arteries was suppressed by an ACE inhibitor, but the remainder was blocked by chymostatin. In hamster hypertensive models, ANG II formation by ACE, but not by chymase, in vascular tissues plays an important role in maintaining hypertension. ANG II formation also induces vascular remodeling such as neointima formation. After balloon injury of vessels in dog, chymase and ACE activities were significantly increased in the injured vessels. In this model, an ANG II receptor antagonist was effective in preventing neointimal formation after balloon injury of vessels in dog, but an ACE inhibitor was ineffective. In dog grafted veins, the activities of chymase and ACEmin the grafted vein were significantly increased 15- and 2-fold, respectively, compared with those in the symmetrical veins. The intimal area of the grafted vein was reduced by a chymase inhibitor. Therefore, chymase-dependent ANG II formation plays an important role in the proliferative response, and chymase inhibitors may appear useful for preventing vascular proliferation.

Topics: Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Chymases; Chymotrypsin; Cricetinae; Dogs; Enzyme Inhibitors; Humans; Hypertension; Neovascularization, Physiologic; Oligopeptides; Rats; Serine Endopeptidases; Serine Proteinase Inhibitors; Species Specificity; Vasoconstriction

Bioactive plant peptides have received considerable interest as potential antihypertensive agents with potentially fewer side effects than antihypertensive drugs. Here, the blood pressure-lowering effects of the Bowman-Birk protease inhibitor, BTCI, and its derived peptides, PepChy and PepTry, were investigated using normotensive (Wistar-WR) and spontaneously hypertensive rats (SHR). BTCI inhibited the proteases trypsin and chymotrypsin, respectively, at 6 µM and 40 µM, a 10-fold greater inhibition than observed with PepTry (60 µM) and PepChy (400 µM). These molecules also inhibited angiotensin converting enzyme (ACE) with IC

Topics: Animals; Antihypertensive Agents; Binding Sites; Blood Pressure; Chymotrypsin; Coronary Vessels; Enzyme Inhibitors; Hypertension; Male; Molecular Docking Simulation; Myocardial Contraction; NG-Nitroarginine Methyl Ester; Nitric Oxide Synthase Type III; Peptides; Peptidyl-Dipeptidase A; Protein Binding; Protein Interaction Domains and Motifs; Protein Structure, Secondary; Rats; Rats, Inbred SHR; Rats, Wistar; Trypsin; Trypsin Inhibitor, Bowman-Birk Soybean; Vasodilation

Hypertensive cardiac remodeling is a major cause of heart failure. The immunoproteasome is an inducible form of the proteasome and its catalytic subunit β5i (also named LMP7) is involved in angiotensin II-induced atrial fibrillation; however, its role in deoxycorticosterone-acetate (DOCA)-salt-induced cardiac remodeling remains unclear. C57BL/6 J wild-type (WT) and β5i knockout (β5i KO) mice were subjected to uninephrectomy (sham) and DOCA-salt treatment for three weeks. Cardiac function, fibrosis, and inflammation were evaluated by echocardiography and histological analysis. Protein and gene expression levels were analyzed by quantitative real-time PCR and immunoblotting. Our results showed that after 21 days of DOCA-salt treatment, β5i expression and chymotrypsin-like activity were the most significantly increased factors in the heart compared with the sham control. Moreover, DOCA-salt-induced elevation of blood pressure, adverse cardiac function, chamber and myocyte hypertrophy, interstitial fibrosis, oxidative stress, and inflammation were markedly attenuated in β5i KO mice. These findings were verified in β5i inhibitor PR-957-treated mice. Moreover, blocking of PTEN (the gene of phosphate and tensin homolog deleted on chromosome ten) markedly attenuated the inhibitory effect of β5i knockout on DOCA-salt-induced cardiac remodeling. Mechanistically, DOCA-salt stress upregulated the expression of β5i, which promoted the degradation of PTEN and the activation of downstream signals (AKT/mTOR, TGF-β1/Smad2/3, NOX, and NF-κB), which ultimately led to cardiac hypertrophic remodeling. This study provides new evidence of the critical role of β5i in DOCA-salt-induced cardiac remodeling through the regulation of PTEN stability, and indicates that the inhibition of β5i may be a promising therapeutic target for the treatment of hypertensive heart diseases.

Topics: Animals; Cardiomegaly; Chymotrypsin; Desoxycorticosterone Acetate; Fibrosis; Hypertension; Inflammation; Male; Mice, Inbred C57BL; Mice, Knockout; Oxidative Stress; Proteasome Endopeptidase Complex; Protein Subunits; PTEN Phosphohydrolase; Signal Transduction; Up-Regulation; Ventricular Remodeling

The mechanisms underlying cell and organ dysfunctions in hypertension are uncertain. The spontaneously hypertensive rat (SHR) has elevated levels of unchecked degrading proteases compared to the control Wistar Kyoto (WKY) rat. The extracellular proteases destroy membrane receptors leading to cell dysfunctions, including arteriolar constriction and elevated blood pressure. Our goal was to identify potential sources of the uncontrolled enzymatic activity.. Zymographic and digital immunohistochemical measurements in SHR pancreas and intestine were obtained as part of the digestive system with high levels of degrading enzymes.. The results showed that SHRs have significantly higher protease activity than WKY in pancreas (22.04 ± 9.01 vs 13.02 ± 3.92 casein fluorescence intensity unit; P < 0.05) and pancreatic venules (0.011 ± 0.003 vs 0.005 ± 0.003 trypsin absorbance; P < 0.05) as well as in venous blood (71.07 ± 13.92 vs 36.44 ± 16.59 casein fluorescence intensity unit; P < 0.05). The enzymatic activity is contributed by trypsin and chymotrypsin. Furthermore, a decrease of these enzyme activity levels achieved during a short-term fasting period is associated with a reduction in systolic blood pressurein SHR (135 ± 8 mm Hg vs 124 ± 7 mm Hg; P < 0.05).. The results suggest the pancreas of the SHR is a potential source for serine proteases leaking into the circulation and contributing to its protease activity.

Topics: Animals; Caloric Restriction; Chymotrypsin; Hypertension; Male; Pancreas; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Trypsin

To determine the role of proteasome proteolysis in the pathogenesis of hypertension, we have studied the proteolytic activity of the proteasome in the aorta and heart tissues of rats with spontaneous hypertension (line SHR), and used quercetin, the drug that can inhibit the activity of this multicatalytic complex. In the aorta of SHR, the activities of the proteasome were not significantly different from that observed in Wistar rats. At the same time, in the heart tissues the trypsin-like (at 40%, P > 0.05), and chymotrypsin-like (by 1.7 times, P < 0.03) activities were significantly less in SHR. Significant morphological changes (fibrosis of the left ventricle was 4.7%, aorta intima width was increased and heart weight index was higher by 21.6% (3.7 +/- 0.6 mg/g) compared with Wistar rats (2.9 +/- 0,4 mg/g, P < 0.004) were observed in these animals functional disorders (reduced stroke volume by 3 times (P < 0.0001), ejection fraction by 2.5 times (P < 0.0001), increased end diastolic pressure by 6.5 times (P < 0.005), end systolic pressure by 15% (P < 0.004)) were revealed. Pharmacological drug "Qvercetin" effectively inhibited trypsin-like and chymotrypsin-like proteasome activities in the aorta (2.7-fold (P < 0.005) and 2-fold (P < 0.003), correspondingly) and trypsin-like, and peptidyl-glutamyl peptide-hydrolyzing-like activities (2.4-fold, P > 0.05 and 9.3-fold, P < 0.02, correspondingly) activities in the heart, leading to a significant improvement of morphological and functional parameters of the heart. Whereas the drug "Qvercetin" that is widely used in clinical practice (especially in therapy of acute myocardial infarction) it could be recommended for the use in prevention of cardiac remodeling with high level of blood pressure.

Topics: Animals; Antioxidants; Aorta; Blood Pressure; Chymotrypsin; Fibrosis; Heart Ventricles; Hypertension; Male; Proteasome Endopeptidase Complex; Quercetin; Rats; Rats, Inbred SHR; Rats, Wistar; Stroke Volume; Trypsin

The tannins are natural polyphenols, able to precipitate water-soluble alkaloids and possess an inhibitory action on the angiotensin converting enzyme (ACE). We identified 18 polyphenolic compounds (tannins) from Chinese herbs and examined the in vitro effects of these tannins on ACE activity, including determination of the 50% inhibitory concentrations (IC50), specificity and mode of inhibition. We also assessed the in vivo inhibitory effect of the tannins on angiotensin I-induced blood pressure elevation in spontaneously hypertensive rats (SHR). Nine tannins with an IC50 <200 microM for ACE inhibitors were identified belonging to three tannin classes: caffeoylquinates, flavan-3-ols and gallotannins. In vitro, we found caffeoylquinates chelate the ACE zinc cofactor. Two of the flavan-3-ols: epigallocatechin-3-O-gallate and epigallocatechin-3-O-methylgallate, and one of gallotannin: 1, 2, 3, 4, 6-penta-O-galloyl-beta-D-glucose were non-specific inhibitors because also reduced the activity of trypsin and chymotrypsin. The ACE inhibition of 1, 2, 3, 4, 6-penta-O-galloyl-beta-D-glucose was also reduced after addition of bovine serum albumin, suggesting a non-specific mode of action. In vivo, 1,2,3,6-tetra-O-galloyl-beta-D-glucose and epigallocatechin-3-O-methylgallate had a strong dose-dependent hypotensive effect reducing the blood pressure significantly in the SHR with infusion of the angiotensin I. These findings indicate that some of the tannins isolated from herbs inhibit ACE activity non-specifically. The ACE inhibitory effect of these tannins may explain the hypotensive effects of some traditional Chinese herbs.

Topics: Angiotensin I; Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Blood Pressure; Chlorides; Chymotrypsin; Dose-Response Relationship, Drug; Drugs, Chinese Herbal; Hypertension; Inhibitory Concentration 50; Medicine, Chinese Traditional; Mouthwashes; Peptidyl-Dipeptidase A; Rats; Rats, Inbred SHR; Substrate Specificity; Tannins; Trypsin; Zinc Compounds

The biochemical characteristics of calmodulin-phosphodiesterase (CaM-PDE) are described. It is a cytosolic, hydrophobic, and heat-, acid-, and base-stable compound sensitive to proteases. It is optimally extracted from neutral supernatants by CHCl3/MeOH (2:1 or 1:1). It partitions into the organic fraction of CHCl3/MeOH extracts, whereas the aqueous fraction contains a component that potentiates the activator's capacity to stimulate CaM-PDE. The activator interacts with PDE by increasing its apparent affinity for CaM. Size partition chromatography of CHCl3/MeOH extracts from spontaneously hypertensive rats produces two activity peaks, one eluting at void volume with the second eluting at a position corresponding to a 4-kDa peptide. The compound at void volume can be converted to the 4-kDa entity by sonication. The CaM-PDE activator behaves as a lipopeptide that shares several characteristics with parathyroid hypertensive factor.

Topics: Acid-Base Equilibrium; Animals; Calmodulin; Chromatography, Affinity; Chromatography, Gel; Chymotrypsin; Enzyme Activation; Heart; Hydrogen-Ion Concentration; Hydrolysis; Hypertension; Mice; Myocardium; Phosphoric Diester Hydrolases; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Tissue Extracts; Trypsin

Topics: Arteriosclerosis; Blindness; Chymotrypsin; Diabetes Complications; Eye Diseases; Hemorrhage; Humans; Hypertension; Phlebitis; Visual Fields; Vitreous Body

Topics: Amine Oxidase (Copper-Containing); Animals; Animals, Newborn; Chemistry, Pharmaceutical; Chromatography; Chymotrypsin; Guinea Pigs; Hypertension; Ileum; Kidney; Muscle, Smooth; Nephrectomy; Nucleosides; Rabbits; Rats; Renal Artery Obstruction; Research; Stomach; Tissue Extracts; Trypsin; Ultraviolet Rays; Venoms

Topics: Anticoagulants; Antihypertensive Agents; Cerebrovascular Disorders; Chymotrypsin; Disease Management; Humans; Hypertension; Reserpine; Stroke; Vasodilator Agents

Topics: Choroid; Choroid Diseases; Chymotrypsin; Disease; Humans; Hydrocortisone; Hypertension; Retina; Retinal Diseases