Bradykinin regulates the expression of kininogen binding sites on endothelial cells

Abstract

The vasoactive compound bradykinin (BK) is liberated by proteolytic cleavage from high molecular weight kininogen (HK) and low molecular weight kininogen (LK). Expression of kininogens on cell surface receptors may affect the delivery of BK at sites of inflammation. Therefore, we investigated whether BK itself alters the expression of binding sites for its parent molecules, HK and LK, on the surface of cultured human umbilical vein endothelial cells (HUVEC). 125I-LK and 125I-HK each bind to a single class of sites on HUVEC in reactions that are saturable, reversible, and zinc-dependent (Bmax = 9.7 +/- 0.2 x 10(5) sites/cell; kd = 43.3 +/- 8 nmol/L; n = 5 and Bmax = 10.3 +/- 0.4 x 10(5) sites/cell; kd = 40.3 +/- 0.9 nmol/L; n = 3 for LK and HK, respectively). HK and LK compete for the same binding site (Ki = 19.4 +/- 5 nmol/L HK v 125I-LK; Ki = 24.5 +/- 4 nmol/L LK v 125I-HK, n = 3). Moreover, 50-fold molar excess light chain of HK inhibits 125I-LK binding 51% and 50-fold molar excess LK and the heavy chain of HK inhibit 125I-light chain of HK binding 92% and 76%, respectively. Preincubation of HUVEC with BK produces a transient, concentration- dependent increase in the binding of HK and LK, reaching a maximum 3 to 4 hours after addition of BK (46% increase over control for HK; 57% increase over control for LK; P < .005 for each ligand). Des-Arg9- bradykinin, a B1 receptor agonist, increases kininogen binding to the same extent as BK; the upregulation of kininogen binding sites by BK is partially blocked by a B1 but not by a B2 receptor antagonist. The protein kinase C inhibitors (PKC), sphingosine and H7, completely block the induction of HK receptors by BK. Phorbol 12-myristate 13-acetate (PMA), which also activates PKC, stimulates the binding of HK and the purified light chain of HK to HUVEC as well. However, unlike HK and its light chain, binding of LK and the heavy chain of HK are increased by PMA only in the presence of added calcium ion. These studies show that BK upregulates a common binding site for HK, LK, and each chain of HK on HUVEC. Induction of kininogen receptors on endothelial cells by BK may modulate the generation of this vasoactive compound at sites of vascular injury.

Contact System: A Vascular Biology Modulator With Anticoagulant, Profibrinolytic, Antiadhesive, and Proinflammatory Attributes

“…The finding Alternatively, Hasan et al 56 indicate that the kininogens' that LK and its isolated heavy chain bind to platelets and thrombin inhibitory activity previously ascribed to domain endothelial cells indicates that there is a cell binding region 3, 50 prepared by proteolytic cleavage, is really domain 4, or on kininogens' heavy chain. 35,48,49 This point was confirmed the kinin moiety remaining attached to the C-terminus of by direct studies using isolated and recombinant domain 3 domain 3. When pure or plasma HK is cleaved by plasma that contained the heavy chain cell binding region on platekallikrein on an artificial surface, bradykinin is liberated lets 50 and neutrophils.…”

“…34 Although calcium ions are im-and thus functioned as a binding site (Fig 2). Another peptide (C211-C229) C-terminal to this peptide was a direct portant for phorbol 12-myristate 13-acetate upregulation of LK and heavy chain binding to endothelial cells, 35 there is inhibitor of calpain (IC 50 Å 35 mmol/L). The two regions probably form a continuous binding site on the three-dimen-no good evidence that calcium ions participate in HK binding to cells, 31,36 contrary to other laboratories' work.…”

“…[75][76][77] The affinity of prekallikrein for its binding site on the light chain of HK is as an additional cell binding site on platelets, granulocytes, and endothelial cells. 35,49,51,66 Two areas of D5 H were found to about 17 nmol/L. 78,79 The prekallikrein and factor XI binding site consists of a 31-residue sequence that contains predomi-participate in cell binding.…”

Single‐chain factor XII exhibits activity when complexed to polyphosphate

“…FXI and PK require a non-enzymatic cofactor, high molecular weight kininogen (HK), to facilitate binding of these proteins to the activating surface, whereas FXII directly associates with the surface via the fibronectin domains in the heavy chain [1][2][3][4]. Zinc ions induce conformational changes in FXII [5][6][7][8][9] and HK [10][11][12], enhancing the interaction of these proteins with the anionic surface.…”

Effect of single-chain and two-chain high molecular weight kininogen on adsorption of fibrinogen from binary mixtures to glass and sulfonated polyurethane surfaces

“…Circulating HK is a well-characterized single-chain plasma glycoprotein [20][21][22][23][24][25][26][27][28][29][30] with a molecular mass of 120 kD and a normal plasma concentration of 30-90 g/ mL. 29 As well as possessing kinin-generating activity, it functions as a nonenzymatic cofactor in the contact activation of plasma coagulation, which occurs most notably at negatively charged surfaces.…”