Lys-[Des-Arg9]Bradykinin

Release of biologically active kinin peptides, Met-Lys-bradykinin and Leu-Met-Lys-bradykinin from human kininogens by two major secreted aspartic proteases of Candida parapsilosis.[Pubmed:23954712]

Peptides. 2013 Oct;48:114-23.

In terms of infection incidence, the yeast Candida parapsilosis is the second after Candida albicans as causative agent of candidiases in humans. The major virulence factors of C. parapsilosis are secreted aspartic proteases (SAPPs) which help the pathogen to disseminate, acquire nutrients and dysregulate the mechanisms of innate immunity of the host. In the current work we characterized the action of two major extracellular proteases of C. parapsilosis, SAPP1 and SAPP2, on human kininogens, proteinaceous precursors of vasoactive and proinflammatory bradykinin-related peptides, collectively called the kinins. The kininogens, preferably the form with lower molecular mass, were effectively cleaved by SAPPs, with the release of two uncommon kinins, Met-Lys-bradykinin and Leu-Met-Lys-bradykinin. While optimal at acidic pH (4-5), the kinin release yield was only 2-3-fold lower at neutral pH. These peptides were able to interact with cellular kinin receptors of B2 subtype and to stimulate the human endothelial cells HMEC-1 to increased secretion of proinflammatory interleukins (ILs), IL-1beta and IL-6. The analysis of the stability of SAPP-generated kinins in plasma suggested that they are biologically equivalent to bradykinin, the best agonist of B2 receptor subtype and can be quickly converted to des-Arg(9)-bradykinin, the agonist of inflammation-inducible B1 receptors.

Extracellular aspartic protease SAP2 of Candida albicans yeast cleaves human kininogens and releases proinflammatory peptides, Met-Lys-bradykinin and des-Arg(9)-Met-Lys-bradykinin.[Pubmed:22944684]

Biol Chem. 2012 Aug;393(8):829-39.

Bradykinin-related peptides, universal mediators of inflammation collectively referred to as the kinins, are often produced in excessive amounts during microbial infections. We have recently shown that the yeast Candida albicans, the major fungal pathogen to humans, can exploit two mechanisms to enhance kinin levels at the sites of candidial infection, one depending on adsorption and activation of the endogenous kinin-generating system of the host on the fungal cell wall and the other relying on cleavage of kinin precursors, the kininogens, by pathogen-secreted proteases. This work aimed at assigning this kininogenase activity to the major secreted aspartic protease of C. albicans (SAP2). The purified SAP2 was shown to cleave human kininogens, preferably the low molecular mass form (LK) and optimally in an acidic environment (pH 3.5-4.0), and to produce two kinins, Met-Lys-bradykinin and its derivative, [Hydroxyproline(3)]-Met-Lys-bradykinin, both of which are capable of interacting with cellular bradykinin receptors of the B2 subtype. Additionally, albeit with a lower yield, des-Arg(9)-Met-Lys-bradykinin, an effective agonist of B1-subtype receptors, was released. The pathophysiological potential of these kinins and des-Arg-kinin was also proven by presenting their ability to stimulate human promonocytic cells U937 to release proinflammatory interleukin 1beta (IL-1beta) and IL-6.

Met-Lys-bradykinin-Ser-Ser, a peptide produced by the neutrophil from kininogen, is metabolically activated by angiotensin converting enzyme in vascular tissue.[Pubmed:21864683]

Pharmacol Res. 2011 Nov;64(5):528-34.

Bradykinin (BK) is a vasoactive nonapeptide cleaved from circulating kininogens and that is degraded by angiotensin converting enzyme (ACE). It has been reported that the PR3 protease from human neutrophil releases an alternate peptide of 13 amino acids, Met-Lys-BK-Ser-Ser, from high molecular weight kininogen. We have studied vascular actions of this kinin. Its affinity for recombinant B(1) and B(2) receptors is very low, as assessed by the binding competition of [(3)H]Lys-des-Arg(9)-BK and [(3)H]BK, respectively, but Met-Lys-BK-Ser-Ser effectively displaced a fraction of [(3)H]enalaprilat binding to recombinant ACE. Mutant recombinant ACE constructions revealed that affinity gap between BK and Met-Lys-BK-Ser-Ser is larger for the N-terminal catalytic site than for the C-terminal one, based on competition for the substrate Abz-Phe-Arg-Lys(Dnp)-Pro-OH in an enzymatic assay. Met-Lys-BK-Ser-Ser is a low potency stimulant of the rabbit aorta (bioassay for B(1) receptors), but the human isolated umbilical vein, a contractile bioassay for the B(2) receptors, responded to Met-Lys-BK-Ser-Ser more than expected from the radioligand binding assay, this agonist being approximately 30-fold less potent than BK in the vein. Venous tissue treatment with the ACE inhibitor enalaprilat reduced the apparent potency of Met-Lys-BK-Ser-Ser by 15-fold, while not affecting that of BK. In the rabbit isolated jugular vein, Met-Lys-BK-Ser-Ser is nearly as potent as BK as a contractile stimulant of endogenous B(2) receptors (EC(5)(0) values of 16.3 and 10.5 nM, respectively), but enalaprilat reduced the potency of Met-Lys-BK-Ser-Ser 13-fold while increasing that of BK 5.3-fold. In vascular tissue, ACE assumes a paradoxical activating role for Met-Lys-BK-Ser-Ser.

Lys-des[Arg9]-bradykinin alters migration and production of interleukin-12 in monocyte-derived dendritic cells.[Pubmed:21177981]

Am J Respir Cell Mol Biol. 2011 Sep;45(3):542-9.

This study tested the hypothesis that proinflammatory kinin peptides are involved in modulating human dendritic cell (DC) function. Inflammation is accompanied by an increased maturation of DCs and the generation of kinins, particularly Lys-des[Arg(9)]-bradykinin (Lda-BK). We assessed the role of Lda-BK in the activation and migration of human monocyte-derived DCs (hMo-DCs) matured through the use of LPS, TNF-alpha + IL-1beta, or CD40 ligand. Kinin B(1) and B(2) receptor mRNA and protein expression were assessed by confocal microscopy, flow cytometry, and RT-PCR. The effects of Lda-BK on the migration of mature hMo-DCs were assessed in Transwell chambers, whereas the expression of costimulatory molecules and the secretion of IL-12 were assessed by flow cytometry and ELISA, respectively. The expression of the kinin B(1) receptor (B(1)R) was down-regulated during the maturation of hMo-DCs, whereas the expression of B(2)R was unchanged. The B(1)R agonist Lda-BK was not chemotactic for hMo-DCs matured using LPS, TNF-alpha + IL-1beta, or CD40 ligand, but Lda-BK enhanced the secretion of IL-12p70 and inhibited the secretion of IL-12p40 by mature hMo-DCs. However, the exposure of hMo-DCs matured with TNF-alpha + IL-1beta to Lda-BK for 6 hours decreased subsequent migration in response to Lda-BK, the chemokine CCL19, or Lda-BK combined with CCL19. The expression of B(1)R was increased in hMo-DCs from subjects with asthma compared with subjects without asthma, in keeping with a tendency toward increased in vitro migration of asthmatic hMo-DCs in response to Lda-BK. The increased formation of Lda-BK and the enhanced expression of B(1)R as a consequence of inflammation may alter the migration of mature, antigen-laden DCs to regional lymph nodes in response to CCL19, may modulate the secretion of cytokines by these DCs, and may contribute to the accumulation of mature DCs in the lungs of patients with asthma.

International union of pharmacology. XLV. Classification of the kinin receptor family: from molecular mechanisms to pathophysiological consequences.[Pubmed:15734727]

Pharmacol Rev. 2005 Mar;57(1):27-77.

Kinins are proinflammatory peptides that mediate numerous vascular and pain responses to tissue injury. Two pharmacologically distinct kinin receptor subtypes have been identified and characterized for these peptides, which are named B1 and B2 and belong to the rhodopsin family of G protein-coupled receptors. The B2 receptor mediates the action of bradykinin (BK) and lysyl-bradykinin (Lys-BK), the first set of bioactive kinins formed in response to injury from kininogen precursors through the actions of plasma and tissue kallikreins, whereas the B(1) receptor mediates the action of des-Arg9-BK and Lys-des-Arg9-BK, the second set of bioactive kinins formed through the actions of carboxypeptidases on BK and Lys-BK, respectively. The B2 receptor is ubiquitous and constitutively expressed, whereas the B1 receptor is expressed at a very low level in healthy tissues but induced following injury by various proinflammatory cytokines such as interleukin-1beta. Both receptors act through G alpha(q) to stimulate phospholipase C beta followed by phosphoinositide hydrolysis and intracellular free Ca2+ mobilization and through G alpha(i) to inhibit adenylate cyclase and stimulate the mitogen-activated protein kinase pathways. The use of mice lacking each receptor gene and various specific peptidic and nonpeptidic antagonists have implicated both B1 and B2 receptors as potential therapeutic targets in several pathophysiological events related to inflammation such as pain, sepsis, allergic asthma, rhinitis, and edema, as well as diabetes and cancer. This review is a comprehensive presentation of our current understanding of these receptors in terms of molecular and cell biology, physiology, pharmacology, and involvement in human disease and drug development.

Classification of kinin receptors.[Pubmed:11258668]

Biol Chem. 2001 Jan;382(1):31-5.

This minireview is divided into three parts: the first part refers to the characterization and classification of kinin receptors using agonists and antagonists in isolated tissues (classical pharmacology). Two kinin receptors have been considered on the basis of their distinct pharmacology, namely the B1 receptor of the rabbit aorta (rank order of potency of agonists: LysdesArg9BK > desArg9BK > or = LysBK > BK; apparent affinities of antagonists Lys[Leu8]desArg9BK (pIC50 8.4) > [Leu8]desArg9BK (pIC50 7.4) >>> HOE 140, a B2 receptor antagonist, pIC50<5.0), and the B2 receptor of the rabbit jugular vein (potency of agonists: LysBK = BK >>> LysdesArg9BK = desArg9BK and HOE 140 (pIC50 9.0) >>> Lys[Leu8]desArg9BK, pIC50<5.0). The second part describes species-related B1 receptor subtypes, demonstrated by different pharmacological profiles of agonists and antagonists: human, rabbit and pig subtypes (LysdesArg9BK >> desArg9BK and Lys[Leu8]desArg9BK > [Leu8]desArg9BK) and dog, rat, mouse and hamster B1 receptors (desArg9BK = LysdesArg9BK and [Leus]desArg9BK = Lys[Leu8]desArg9BK). Affinities of agonists and antagonists in some species (man, rabbit, pig) are significantly increased (at least 10-fold) by the presence of a Lys at their N-terminus. The last part describes species-related B2 receptor subtypes supported by results obtained with non-peptide receptor agonists (FR 190997) and antagonists (FR 173657). While BK acts as a full agonist in man, rabbit and pig, FR 190997 behaves as a full agonist on human, as partial agonist on rabbit, and as pure antagonist on pig B2 receptors. Various hypotheses are considered to interpret these findings.

Hypotensive effects of Lys-des-Arg9-bradykinin and metabolically protected agonists of B1 receptors for kinins.[Pubmed:1662280]

J Pharmacol Exp Ther. 1991 Dec;259(3):997-1003.

B1 receptors for kinins are selectively stimulated by bradykinin (BK) or Lys-BK (kallidin) fragments without the C terminal arginine residue. The present study was performed using an established in vivo model of B1 receptor-mediated cardiovascular action. Rabbits pretreated with bacterial lipopolysaccharide (LPS) (25 micrograms/kg) and anesthetized 5 h later exhibit acute and transient hypotension in response to intra-arterial boluses of B1 receptor agonists. The naturally occurring B1 agonist Lys-des-Arg9-BK was more potent than des-Arg9-BK in the in vivo model, but the effect of either natural sequence was brief. Evidence derived from previous in vitro experiments suggests these peptides may be substrates for angiotensin I converting enzyme (ACE). In addition, Lys-des-Arg9-BK is hydrolyzed in vitro by aminopeptidase M. Therefore, we tested the hypotensive effects of Lys-des-Arg9-BK analogs selectively protected against ACE activity (Lys-[D-Phe8]des-Arg9-BK) or against both ACE and aminopeptidase M (Sar-[D-Phe8]des-Arg9-BK). Both analogs were found to elicit a biphasic response consisting of a brief hypotensive effect followed by a prolonged hypotensive state. Indomethacin prevented only the second, prolonged phase of the hypotension induced by the metabolically protected analogs. The duration of hypotensive episodes induced by Lys-des-Arg9-BK was increased in rabbits pretreated with either captopril, an ACE inhibitor, or the aminopeptidase M inhibitor amastatin, consistent with the prolonged effect of metabolically protected analogs. An infusion of the B1 agonist Sar-[D-Phe8]des-Arg9-BK (1 microgram/min) in lipopolysaccharide-pretreated rabbits led to a very important and persistent hypotensive state that was not prevented by indomethacin.(ABSTRACT TRUNCATED AT 250 WORDS)