scholarly journals Cathepsin K: a cysteine protease with unique kinin-degrading properties

2004 ◽  
Vol 383 (3) ◽  
pp. 501-506 ◽  
Author(s):  
Emmanuel GODAT ◽  
Fabien LECAILLE ◽  
Claire DESMAZES ◽  
Sophie DUCHÊNE ◽  
Enrico WEIDAUER ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Smooth Muscles ◽  
Cathepsin K ◽  
Cysteine Proteases ◽  
Unique Property ◽  
Converting Enzyme ◽  
Aminobenzoic Acid ◽  
Wild Type ◽  
Dose Dependent ◽  
Type Receptor

Taking into account a previous report of an unidentified enzyme from macrophages acting as a kininase, the ability of cysteine proteases to degrade kinins has been investigated. Wild-type fibroblast lysates from mice, by contrast with cathepsin K-deficient lysates, hydrolysed BK (bradykinin), and released two metabolites, BK-(1–4) and BK-(5–9). Cathepsin K, but not cathepsins B, H, L and S, cleaved kinins at the Gly4–Phe5 bond and the bradykinin-mimicking substrate Abz (o-aminobenzoic acid)-RPPGFSPFR-3-NO2-Tyr (3-nitrotyrosine) more efficiently (pH 6.0: kcat/Km=12500 mM−1·s−1; pH 7.4: kcat/Km=6930 mM−1·s−1) than angiotensin-converting enzyme hydrolysed BK. Conversely Abz-RPPGFSPFR-3-NO2-Tyr was not cleaved by the Y67L (Tyr67→Leu)/L205A (Leu205→Ala) cathepsin K mutant, indicating that kinin degradation mostly depends on the S2 substrate specificity. Kininase activity was further evaluated on bronchial smooth muscles. BK, but not its metabolites BK(1-4) and BK(5-9), induced a dose-dependent contraction, which was abolished by Hoe140, a B2-type receptor antagonist. Cathepsin K impaired BK-dependent contraction of normal and chronic hypoxic rats, whereas cathepsins B and L did not. Taking together vasoactive properties of kinins and the potency of cathepsin K to modulate BK-dependent contraction of smooth muscles, the present data support the notion that cathepsin K may act as a kininase, a unique property among mammalian cysteine proteases.

Vascular Angiotensin-Converting Enzyme Activity in Man and other Species

1984 ◽  
Vol 66 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Mizuo Miyazaki ◽  
Hideki Okunishi ◽  
Kazuo Nishimura ◽  
Noboru Toda
Keyword(s):  
Angiotensin Converting Enzyme ◽  
High Performance ◽  
Muscle Tone ◽  
Chloride Ion ◽  
Kidney Cortex ◽  
Dependent Manner ◽  
Converting Enzyme ◽  
Aortic Endothelial Cells ◽  
Ace Activity ◽  
Dose Dependent

1. Angiotensin-converting enzyme (ACE) activity in blood vessels of different species was determined. 2. ACE was solubilized by Nonidet P-40, and assayed by reversible phase high performance liquid chromatography. Approximately 98% ACE was recovered in the liquid phase by the use of the detergent. 3. The ACE activity varied with chloride ion (Cl−) concentrations; the maximum activities in dog, human, monkey and rabbit tissues were obtained at the concentrations of 800, 600, 600 and 300 mmol/l respectively. The optimal Cl− concentration was quite similar in different tissues and plasma obtained from the same species. 4. The ACE activity in the cerebral, mesenteric, pulmonary and renal arteries was in a range between 1.01 and 1.60 m-units/mg of protein in dogs and between 0.43 and 0.94 m-unit/mg of protein in monkeys. The activity in dog aortae was 0.20 ± 0.02 m-unit/mg of protein, and the activity in aortic endothelial cells was 2.61 ± 0.65 m-units/mg of protein. ACE activities in the dog lung, kidney cortex and cerebral cortex were 28.6 ± 2.6, 15.7 ± 3.0 and 3.5 ± 0.6m-units/mg of protein respectively. SA-446, a captopril-like ACE inhibitor, reduced the ACE activity in arteries in a dose-dependent manner. 5. Vascular ACE appears to be concentrated in the endothelium and may contribute to regulate vascular muscle tone and local blood flow by a conversion of angiotensin I into II.

scholarly journals Antibody binding and ACE2 binding inhibition is significantly reduced for the Omicron variant compared to all other variants of concern

2022 ◽  
Author(s):  
Daniel Junker ◽  
Matthias Becker ◽  
Teresa Wagner ◽  
Philipp D Kaiser ◽  
Sandra Maier ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Antibody Binding ◽  
Large Cohort ◽  
Converting Enzyme ◽  
Wild Type ◽  
Immune Control ◽  
Angiotensin Converting Enzyme 2 ◽  
Igg Binding ◽  
Binding Inhibition ◽  
Rapid Emergence

The rapid emergence of the Omicron variant and its large number of mutations has led to its classification as a variant of concern (VOC) by the WHO. Initial studies on the neutralizing response towards this variant within convalescent and vaccinated individuals have identified substantial reductions. However many of these sample sets used in these studies were either small, uniform in nature, or were compared only to wild-type (WT) or, at most, a few other VOC. Here, we assessed IgG binding, (Angiotensin-Converting Enzyme 2) ACE2 binding inhibition, and antibody binding dynamics for the omicron variant compared to all other VOC and variants of interest (VOI), in a large cohort of infected, vaccinated, and infected and then vaccinated individuals. While omicron was capable of binding to ACE2 efficiently, antibodies elicited by infection or immunization showed reduced IgG binding and ACE2 binding inhibition compared to WT and all VOC. Among vaccinated samples, antibody binding responses towards omicron were only improved following administration of a third dose. Overall, our results identify that omicron can still bind ACE2 while pre-existing antibodies can bind omicron. The extent of the mutations appear to inhibit the development of a neutralizing response, and as a result, omicron remains capable of evading immune control.

Amiodarone induces apoptosis of human and rat alveolar epithelial cells in vitro

2000 ◽  
Vol 278 (5) ◽  
pp. L1039-L1044 ◽  
Author(s):  
Raed Bargout ◽  
Aleksandar Jankov ◽  
Erhan Dincer ◽  
Rongqi Wang ◽  
Themis Komodromos ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
A549 Cell ◽  
Pulmonary Toxicity ◽  
Cell Loss ◽  
Alveolar Epithelial Cells ◽  
Converting Enzyme ◽  
A549 Cell Line ◽  
Alveolar Epithelial ◽  
Induction Of Apoptosis ◽  
Dose Dependent

The antiarrhythmic amiodarone (AM) and its metabolite desethylamiodarone (Des) are known to cause AM-induced pulmonary toxicity, but the mechanisms underlying this disorder remain unclear. We hypothesized that AM might cause AM-induced pulmonary toxicity in part through the induction of apoptosis or necrosis in alveolar epithelial cells (AECs). Two models of type II pneumocytes, the human AEC-derived A549 cell line and primary AECs isolated from adult Wistar rats, were incubated with AM or Des for 20 h. Apoptotic cells were determined by morphological assessment of nuclear fragmentation with propidium iodide on ethanol-fixed cells. Necrotic cells were quantitated by loss of dye exclusion. Both AM and Des caused dose-dependent necrosis starting at 2.5 and 0.1 μg/ml, respectively, in primary rat AECs and at 10 and 5 μg/ml in subconfluent A549 cells ( P < 0.05 and P < 0.01, respectively). AM and Des also induced dose-dependent apoptosis beginning at 2.5 μg/ml in the primary AECs ( P < 0.05 for both compounds) and at 10 and 5 μg/ml, respectively, in the A549 cell line ( P < 0.01). The two compounds also caused significant net cell loss (up to 80% over 20 h of incubation) by either cell type at drug concentrations near or below the therapeutic serum concentration for AM. The cell loss was not due to detachment but was blocked by the broad-spectrum caspase inhibitor Z-Val-Ala-Asp-fluoromethylketone. Furthermore, the angiotensin-converting enzyme inhibitor captopril (500 ng/ml) and the angiotensin-receptor antagonist saralasin (50 μg/ml) significantly inhibited both the induction of apoptosis and net cell loss in response to AM. These results are consistent with recent work from this laboratory demonstrating potent inhibition of apoptosis in human AECs by captopril (Uhal BD, Gidea C, Bargout R, Bifero A, Ibarra-Sunga O, Papp M, Flynn K, and Filippatos G. Am J Physiol Lung Cell Mol Physiol 275: L1013–L1017, 1998). They also suggested that the accumulation of AM and/or its primary metabolite Des in lung tissue may induce cytotoxicity of AECs that might be inhibitable by angiotensin-converting enzyme inhibitors or other antagonists of the renin-angiotensin system.

Angiotensin-converting enzyme limits inflammation elicited by Trypanosoma cruzi cysteine proteases: a peripheral mechanism regulating adaptive immunity via the innate kinin pathway

2008 ◽  
Vol 389 (8) ◽  
Author(s):  
Julio Scharfstein ◽  
Ana Carolina Monteiro ◽  
Veronica Schmitz ◽  
Erik Svensjö
Keyword(s):  
Trypanosoma Cruzi ◽  
Angiotensin Converting Enzyme ◽  
Tissue Injury ◽  
Cysteine Proteases ◽  
Interferon Γ ◽  
Converting Enzyme ◽  
Potential Threat ◽  
Kinin System ◽  
Dc Maturation

AbstractTissue injury by pathogens induces a stereotyped inflammatory response that alerts the innate immune system of the potential threat to host integrity. Here, we review knowledge emerging from investigations of the role of the kinin system in the mechanisms that link innate to the adaptive phase of immunity. Progress in this field started with results demonstrating that bradykinin is an endogenous danger signal that induces dendritic cell (DC) maturation via G protein-coupled bradykinin B2receptors (B2R). The immunostimulatory role of kinins was recently confirmed in two different mouse models ofTrypanosoma cruziinfection, a parasitic protozoan equipped with kinin-releasing cysteine proteases (cruzipain). Infection by the intraperitoneal route showed that DCs from B2R-/-mice (susceptible phenotype) failed to sense kinin ‘danger’ signals proteolytically released by parasites, explaining why these mutant mice display lower frequencies of interferon-γ-producing effector T-cells. Studies of the dynamics of inflammation in the subcutaneous model of infection revealed that the balance between cruzipain and angiotensin-converting enzyme, respectively acting as kinin-generating and degrading enzymes, governs extent of DC maturation and TH1 development via the B2R-dependent innate pathway. Studies of the kinin role in immunity may shed light on the relationship between proteolytic networks and the cytokine circuits that guide T-cell development.

Differential ANG II generation in plasma and tissue of mice with decreased expression of the ACE gene

2002 ◽  
Vol 282 (6) ◽  
pp. H2254-H2258 ◽  
Author(s):  
Chih-Chang Wei ◽  
Baohong Tian ◽  
Gilbert Perry ◽  
Qing Cheng Meng ◽  
Yiu-Fai Chen ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Steady State ◽  
Angiotensin Converting Enzyme ◽  
Ang Ii ◽  
Converting Enzyme ◽  
Heterozygous Deletion ◽  
Wild Type ◽  
Vascular Space ◽  
Plasma Angiotensin ◽  
Ace Activity

We utilized mice with homozygous disruption of angiotensin-converting enzyme (ACE) (−/−), mice with heterozygous deletion of ACE (+/−), and wild-type mice (+/+) to test the hypothesis that genetic variation in ACE modulates tissue and plasma angiotensin (ANG) II concentrations. With the use of ANG I as substrate, kidney, heart, and lung ACE activity was reduced 80% in −/− mice compared with +/+ mice. However, ANG II concentrations and ANG II-to-ANG I ratios in the kidney, heart, and lung did not differ among genotypes. In contrast, plasma ANG II concentrations in −/− mice were <2 fmol/ml, whereas plasma ANG I concentrations were extremely high (765 fmol/ml). Chymase activity was increased 14-fold in the kidney ( P < 0.05) and 1.5-fold in the heart ( P < 0.05) of −/− versus +/+ mice but did not differ among genotypes in the lung. ANG II formation from enzymes other than ACE and chymase contributed <2% of total ANG II formation in all genotypes. These data suggest that ACE is essential to ANG II formation in the vascular space, whereas chymase may provide an important mechanism in maintaining steady-state ANG II levels in tissue.

scholarly journals S3 to S3' subsite specificity of recombinant human cathepsin K and development of selective internally quenched fluorescent substrates

2003 ◽  
Vol 373 (3) ◽  
pp. 981-986 ◽  
Author(s):  
Marcio F. M. ALVES ◽  
Luciano PUZER ◽  
Simone S. COTRIN ◽  
Maria Aparecida JULIANO ◽  
Luiz JULIANO ◽  
...  
Keyword(s):  
Amino Acids ◽  
Cathepsin K ◽  
Cysteine Proteases ◽  
Aminobenzoic Acid ◽  
Hydrophobic Amino Acids ◽  
Human Cathepsin ◽  
General Sequences ◽  
Natural Amino Acids ◽  
Positively Charged ◽  
K Activity

We have systematically examined the S3 to S3′ subsite substrate specificity requirements of cathepsin K using internally quenched fluorescent peptides derived from the lead sequence Abz-KLRFSKQ-EDDnp [where Abz is o-aminobenzoic acid and EDDnp is N-(2,4-dinitrophenyl)ethylenediamine]. We assayed six series of peptides, in which each position except Gln was substituted with various natural amino acids. The results indicated that the S3–S1 subsite requirements are more restricted than those of S1′–S3′. Cathepsin K preferentially accommodates hydrophobic amino acids with aliphatic side chains (Leu, Ile and Val) in the S2 site. Modifications at P1 residues also have a large influence on cathepsin K activity. Positively charged residues (Arg and Lys) represent the best accepted amino acids in this position, although a particular preference for Gly was found as well. Subsite S3 accepted preferentially basic amino acids such as Lys and Arg. A broad range of amino acids was accommodated in the remaining subsites. We further explored the acceptance of a Pro residue in the P2 position by cathepsin K in order to develop specific substrates for the enzyme. Two series of peptides with the general sequences Abz-KXPGSKQ-EDDnp and Abz-KPXGSKQ-EDDnp (where X denotes the position of the amino acid that is altered) were synthesized. The substrates Abz-KPRGSKQ-EDDnp and Abz-KKPGSKQ-EDDnp were cleaved by cathepsin K at the Arg–Gly and Gly–Ser bonds respectively, and have been shown to be specific for cathepsin K when compared with other lysosomal cysteine proteases such as cathepsins L and B and with the aspartyl protease cathepsin D.

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