Replacement of the Transmembrane Anchor in Angiotensin I-converting Enzyme (ACE) with a Glycosylphosphatidylinositol Tail Affects Activation of the B2 Bradykinin Receptor by ACE Inhibitors (original) (raw)
Related papers
Hypertension, 1998
We used the isolated N-and C-domains of the angiotensin I-converting enzyme (N-ACE and C-ACE; ACE; kininase II) to investigate the hydrolysis of the active 1-7 derivative of angiotensin (Ang) II and inhibition by 5-S-5-benzamido-4-oxo-6-phenylhexanoyl-L-proline (keto-ACE). Ang-(1-7) is both a substrate and an inhibitor; it is cleaved by N-ACE at approximately one half the rate of bradykinin but negligibly by C-ACE. It inhibits C-ACE, however, at an order of magnitude lower concentration than N-ACE; the IC 50 of C-ACE with 100 mol/L Ang I substrate was 1.2 mol/L and the K i was 0.13. While searching for a specific inhibitor of a single active site of ACE, we found that keto-ACE inhibited bradykinin and Ang I hydrolysis by C-ACE in approximately a 38-to 47-times lower concentration than by N-ACE; IC 50 values with C-ACE were 0.5 and 0.04 mol/L. Furthermore, we investigated how Ang-(1-7) acts via bradykinin and the involvement of its B 2 receptor. Ang-(1-7) was ineffective directly on the human bradykinin B 2 receptor transfected and expressed in Chinese hamster ovary cells. However, Ang-(1-7) potentiated arachidonic acid release by an ACE-resistant bradykinin analogue (1 mol/L), acting on the B 2 receptor when the cells were cotransfected with cDNAs of both B 2 receptor and ACE and the proteins were expressed on the plasma membrane of Chinese hamster ovary cells. Thus like other ACE inhibitors, Ang-(1-7) can potentiate the actions of a ligand of the B 2 receptor indirectly by binding to the active site of ACE and independent of blocking ligand hydrolysis. This potentiation of kinins at the receptor level can explain some of the well-documented kininlike actions of Ang-(1-7). (Hypertension. 1998;31:912-917.)
Potentiation of Bradykinin Actions by ACE Inhibitors
Trends in Endocrinology & Metabolism, 1999
Angiotensin I-converting enzyme (kininase II; ACE) inhibitors, antibodies to ACE and slowly cleaved substrates of ACE potentiate the effect of bradykinin and its analogs on their B 2 receptors independently of blocking peptide metabolism. ACE inhibitors also resensitized the receptors desensitized by the ligand (tachyphylaxis). The studies were performed on isolated organs and cells co-transfected with the receptor and the enzyme or constitutively expressing them. This enhancement of the effect of B 2 ligands is attributed to a crosstalk between the enzyme and the receptor, and not to a direct action on the receptors. It might reflect some of the local activities of ACE inhibitors.
Do angiotensin-converting enzyme inhibitors directly stimulate the kinin B1 receptor?
American journal of physiology. Heart and circulatory physiology, 2003
It has been recently claimed that the human B1 receptors for kinins bind angiotensin-converting enzyme (ACE) inhibitors via a potential zinc-binding domain and are pharmacologically stimulated by these drugs. We verified whether ACE inhibitors stimulate B1 receptors in vitro. The isolated rabbit aorta or mouse stomach responded by negligible contractions to the application of captopril, enalaprilat, or zofenoprilat. The human isolated umbilical vein also failed to respond to enalaprilat. All of these preparations were responsive to the B1 receptor agonists des-Arg9-bradykinin (BK) or Lys-des-Arg9-BK. Furthermore, enalaprilat applied continuously had no significant interaction with the effects of Lys-des-Arg9-BK on the rabbit aorta. Enalaprilat failed to stimulate [3H]arachidonate release, translocate the receptors (confocal microscopy), or stimulate ERK1/2 phosphorylation (immunoblot) in HEK-293 cells stably expressing the rabbit B1 receptor conjugated to yellow fluorescent protein....
Products of Angiotensin I Hydrolysis by Human Cardiac Enzymes Potentiate Bradykinin
Journal of Molecular and Cellular Cardiology, 2002
of Angiotensin I Hydrolysis by Human Cardiac Enzymes Potentiate Bradykinin. Journal of Molecular and Cellular Cardiology (2002) 34, 1569±1576. Some bene®cial effects of ACE inhibitors are attributed to potentiation of bradykinin's actions exerted through its B 2 receptor. We investigated them on cultured cells transfected or constitutively expressing both ACE and B 2 receptor. The potentiation of bradykinin was indirect and attributed to a crosstalk induced between enzyme and receptor via ACE, a heterodimer formation. While looking for endogenous activators, we investigated the split products of angiotensin I (Ang) Ang 1±9 and 1±7, peptides released by enzymes of human atria and ventricle. Ang 1±9 was liberated by a cathepsin A-type enzyme, Ang 1±7 by a different metallopeptidase-protease. Cathepsin A's presence in heart tissue was shown by deamidating enkephalinamide substrate, by immunoprecipitation and by immunohistochemistry. In immunohistochemistry, cathepsin A was detected in myocytes of atrial tissue. Ang 1±9 and Ang 1±7 potentiated the effect of an ACE-resistant bradykinin analogue on the B 2 receptor in transfected cells expressing human ACE and B 2 , and in human endothelial cells. Ang 1±9 and 1±7 augmented arachidonic acid and NO release by bradykinin. NO liberation by bradykinin from endothelial cells was potentiated at 10 nmol/L concentration by Ang 1±9 and Ang 1±7; at higher concentrations, Ang 1±9 was signi®cantly more active. Both peptides had little activity in absence of bradykinin or ACE. Ang 1±9 and 1±7 potentiated bradykinin action on its B 2 receptor at much lower concentrations than their IC 50 values with ACE. They probably induce conformational changes in the ACE/B 2 receptor complex via interaction with ACE.
Human ACE and bradykinin B2 receptors form a complex at the plasma membrane
FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 2006
To investigate how angiotensin I-converting enzyme (ACE) inhibitors enhance the actions of bradykinin (BK) on B2 receptors independent of blocking BK inactivation, we expressed human somatic ACE and B2 receptors in CHO cells. Bradykinin and its ACE-resistant analog were the receptor agonists. B2 fused with green fluorescent protein (GFP) and ACE were coprecipitated with antisera to GFP or ACE shown in Western blots. Immunohistochemistry of fixed cells localized ACE by red color and B2-GFP by green. Yellow on plasma membranes of coexpressing cells also indicated enzyme-receptor complex formation. Using ACE-fused cyan fluorescent protein donor and B2-fused yellow fluorescent protein (YFP) acceptor, we registered fluorescence resonance energy transfer (FRET) by the enhanced fluorescence of donor on acceptor photobleaching, establishing close (within 10 nm) positions of B2 receptors and ACE. Bradykinin stimulation cointernalized ACE and B2 receptors. We expressed ACE fused to N terminus...
Hypertension, 2016
The renin-angiotensin system and the kallikrein-kinin system contribute to fluid homeostasis and blood pressure regulation. The renin-angiotensin system is composed of 2 arms with opposing functions. The pressor arm, represented by the angiotensin type 1 receptor (AT 1 R), angiotensin-converting enzyme (ACE), and angiotensin II, is responsible for the vasoconstrictive, proliferative, fibrotic, and hypertensive effects of the renin-angiotensin system. In contrast, the second arm exerts depressor and cardiovascular protective effects through angiotensin-(1-7) (Ang-(1-7)), the Ang-(1-7)-specific receptor Mas that transduces the main physiological actions of Ang-(1-7), and ACE2 that catalyzes the generation of Ang-(1-7) from angiotensin II. 1-3 Bradykinin, generated by the kallikrein-kinin system, exerts cardioprotective, vasodilatory, and depressor properties through B2 receptor (B2 R) stimulation. 4,5 Several studies showed the existence of a cross talk between the renin-angiotensin system and kallikrein-kinin system. 6,7 For instance, kallikrein not only catalyzes the generation of kinin from kininogen, but also acts as a prorenin-activating enzyme leading to an increase in angiotensin II. 6 In addition , ACE not only generates the vasopressor angiotensin II but also responsible for the proteolytic degradation of bradykinin. 6,7 Not only was a cross talk between both systems reported at the enzymatic level, but also between the components of these systems. For example, Ang-(1-7) exerts kinin-like effects and Abstract-Bradykinin B 2 receptor (B 2 R) and angiotensin-(1-7) Mas receptor (MasR)-mediated effects are physiologically interconnected. The molecular basis for such cross talk is unknown. It is hypothesized that the cross talk occurs at the receptor level. We investigated B2R-MasR heteromerization and the functional consequences of such interaction. B2 R fused to the cyan fluorescent protein and MasR fused to the yellow fluorescent protein were transiently coexpressed in human embryonic kidney293T cells. Fluorescence resonance energy transfer analysis showed that B 2 R and MasR formed a constitutive heteromer, which was not modified by their agonists. B 2 R or MasR antagonists decreased fluorescence resonance energy transfer efficiency, suggesting that the antagonist promoted heteromer dissociation. B 2 R-MasR heteromerization induced an 8-fold increase in the MasR ligand-binding affinity. On agonist stimulation, the heteromer was internalized into early endosomes with a slower sequestration rate from the plasma membrane, compared with single receptors. B 2 R-MasR heteromerization induced a greater increase in arachidonic acid release and extracellular signal-regulated kinase phosphorylation after angiotensin-(1-7) stimulation, and this effect was blocked by the B2 R antagonist. Concerning serine/ threonine kinase Akt activity, a significant bradykinin-promoted activation was detected in B2 R-MasR but not in B2 R-expressing cells. Angiotensin-(1-7) and bradykinin elicited antiproliferative effects only in cells expressing B2 R-MasR heteromers, but not in cells expressing each receptor alone. Proximity ligation assay confirmed B2 R-MasR interaction in human glomerular endothelial cells supporting the interaction between both receptors in vivo. Our findings provide an explanation for the cross talk between bradykinin B2 R and angiotensin-(1-7) MasR-mediated effects. B2R-MasR heteromerization induces functional changes in the receptor that may lead to long-lasting protective properties. (Hypertension. 2016;68:00-00.
Background-The physiological effects of ACE inhibitors may act in part through a kinin-dependent mechanism. We investigated the effect of chronic ACE-inhibitor treatment on functional kinin B 1 -and B 2 -receptor expression, which are the molecular entities responsible for the biological effects of kinins. Methods and Results-Rats were subjected to different 6-week treatments using various mixtures of the following agents: ACE inhibitor, angiotensin AT 1 -receptor antagonist, and B 1 -and B 2 -receptor antagonists. Chronic ACE inhibition induced both renal and vascular B 1 -receptor expression, whereas B 2 -receptor expression was not modified. Furthermore, with B 1 -receptor antagonists, it was shown that B 1 -receptor induction was involved in the hypotensive effect of ACE inhibition. Using microdissection, we prepared 10 different nephron segments and found ACE-inhibitor-induced expression of functional B 1 -receptors in all segments. ACE-inhibitor-induced B 1 -receptor induction involved homologous upregulation, because it was prevented by B 1 -receptor antagonist treatment. Finally, using B 2 -receptor knockout mice, we showed that ACE-inhibitor-induced B 1 -receptor expression was B 2 -receptor independent. Conclusions-This study provides the first evidence that chronic ACE-inhibitor administration is associated with functional vascular and renal B 1 -receptor induction, which is involved in ACE-inhibitor-induced hypotension. The observed B 1 -receptor induction in the kidney might participate in the known renoprotective effects of ACE inhibition.
Enhancement of Bradykinin and Resensitization of Its B2 Receptor
Hypertension, 1999
We studied the enhancement of the effects of bradykinin B 2 receptor agonists by agents that react with active centers of angiotensin-converting enzyme (ACE) independent of enzymatic inactivation. The potentiation and the desensitization and resensitization of B 2 receptor were assessed by measuring [ 3 H]arachidonic acid release and [Ca 2ϩ ] i mobilization in Chinese hamster ovary cells transfected to express human ACE and B 2 receptor, or in endothelial cells with constitutively expressed ACE and receptor. Administration of bradykinin or its ACE-resistant analogue desensitized the receptor, but it was resensitized (arachidonic acid release or [Ca 2ϩ ] i mobilization) by agents such as enalaprilat (1 mol/L). Enalaprilat was inactive in the absence of ACE expression. La 3ϩ (100 mol/L) inhibited the apparent resensitization, probably by blocking the entry of extracellular calcium. Enalaprilat resensitized the receptor via ACE to release arachidonic acid by bradykinin at a lower concentration (5 nmol/L) than required to mobilize [Ca 2ϩ ] i (1 mol/L). Monoclonal antibodies inhibiting the ACE N-domain active center and polyclonal antiserum potentiated bradykinin. The snake venom peptide BPP5a and metabolites of angiotensin and bradykinin (angiotensin-[1-9], angiotensin-[1-7], bradykinin-[1-8]; 1 mol/L) enhanced arachidonic acid release by bradykinin. Angiotensin-(1-9) and -(1-7) also resensitized the receptor. Enalaprilat potentiated the bradykinin effect in cells expressing a mutant ACE with a single N-domain active site. Agents that reacted with a single active site, on the N-domain or on the C-domain, potentiated bradykinin not by blocking its inactivation but by inducing crosstalk between ACE and the receptor. Enalaprilat enhanced signaling via ACE by G␣ i in lower concentration than by G␣ q -coupled receptor. (Hypertension. 1999;33:835-843.) Key Words: angiotensin-converting enzyme inhibitors Ⅲ kininase II Ⅲ endothelial cells Ⅲ G proteins Ⅲ [Ca 2ϩ ] i Ⅲ arachidonic acid Ⅲ angiotensin-(1-9)
Vascular Pharmacology, 2012
The expression of the bradykinin (BK) B₁ receptor (B₁R), lacking in normal vascular tissues, is induced following innate immune system activation and chronic blockade of angiotensin converting enzyme (ACE). To identify cytokine-dependent or -independent mechanisms for the latter phenomenon, the ACE inhibitor enalaprilat and several peptides potentiated in vivo by ACE blockade were applied either directly to human umbilical artery smooth muscle cells (hUA-SMCs) or to differentiated monoblastoid U937 cells to produce a conditioned medium (CM) that was later transferred to hUA-SMCs. A phagocyte stimulant, lipopolysaccharide, did not upregulate B₁R, measured using [³H]Lys-des-Arg⁹-BK binding, or translocate NF-κB to the nuclei if applied directly to the hUA-SMCs. However, the CM of lipopolysaccharide-stimulated U937 cells was active in these respects (effects inhibited by etanercept and correlated to TNF-α presence in the CM). A peptidase-resistant B₁R agonist had no significant direct or indirect acute effect (4h) on B₁R expression, but repeated hUA-SMC stimulations over 40 h were stimulatory in the absence of NF-κB activation. Other peptides regulated by ACE or enalaprilat did not directly or indirectly stimulate B₁R expression. The reconstitution system supports the rapid cytokine-dependent vascular induction of B₁Rs and a slow "autoregulatory" one potentially relevant for the ACE blockade effect.