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Activities of wild-type and variant tissue-type plasminogen activators retained on vascular endothelial cells.

ABSTRACT: We reported that tissue-type plasminogen activator (tPA) secreted from vascular endothelial cells (VECs) is retained on the cell surface and effectively evokes both plasminogen activation and fibrin clot dissolution (fibrinolysis) on VECs. Here, to evaluate possibly different behaviors of variants of tPA, we quantitatively assessed these two events separately using green fluorescent protein (GFP)-conjugated tPA in cultured human VECs. The amount of secreted wild-type tPA-GFP correlated well with both the activities of plasminogen activation (r = 0.66) and fibrinolysis (r = -0.93). A variant of tPA-GFP, with a lower affinity to the surface of VECs but higher affinity to fibrin, showed higher fibrinolysis and lower plasminogen activation activity compared to the wild-type.

SUBMITTER: Suzuki Y

PROVIDER: S-EPMC4856425 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature

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Activities of wild-type and variant tissue-type plasminogen activators retained on vascular endothelial cells.

Suzuki Yuko Y Sano Hideto H Tomczyk Martyna M Brzoska Tomasz T Urano Tetsumei T

FEBS open bio 20160401 5

We reported that tissue-type plasminogen activator (tPA) secreted from vascular endothelial cells (VECs) is retained on the cell surface and effectively evokes both plasminogen activation and fibrin clot dissolution (fibrinolysis) on VECs. Here, to evaluate possibly different behaviors of variants of tPA, we quantitatively assessed these two events separately using green fluorescent protein (GFP)-conjugated tPA in cultured human VECs. The amount of secreted wild-type tPA-GFP correlated well with ...[more]

PMID: 27419052

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Project description:The effects of cortisol on the inhibition of cell-death processes and suppression of plasminogen-activator (PA) activity during involution of the rat ventral prostate gland were investigated to determine the principal type of PA activated by castration and inhibited by this hormone and whether the mechanism responsible for decreased PA activity involved reductions in enzyme synthesis or increased activity of a PA inhibitor. By using the technique of fibrin-agarose zymography, three bands of PA activity were detected at 4 and 7 days after castration: a major band with a molecular mass of approx. 30 kDa and two minor bands of 48 kDa and 64 kDa. Both the 30 kDa and 48 kDa activities were inhibited with anti-[urokinase-type PA (u-PA)] IgG. The 64 kDa activity was inhibited by anti-[tissue-type PA (t-PA)] IgG. In addition to retarding prostatic involution, daily administration of cortisol to the castrated animals suppressed all three bands of PA activity. A comparison of the pattern of total PA activity and of e.l.i.s.a. estimates of u-PA concentration during the castration-induced rise and after cortisol inhibition indicated a near perfect correlation between the two parameters. Northern-blot analysis using prostatic polyadenylated RNA revealed that the level of u-PA mRNA was highest at 4 and 7 days after castration and that cortisol treatment repressed u-PA mRNA to a level similar to that in non-castrated controls. Neither Northern hybridizations nor reverse zymography detected RNA transcripts or activity corresponding to the PA inhibitor PAI-1 in any of the prostate samples. Western-blot analysis revealed that, although the amount of arginine esterase A, another prostatic proteinase, also increased after castration, the rise in concentration of this protein was not blocked by glucocorticoid administration. Together our findings indicate the following: (1) the predominant form of PA activity induced in the prostate after castration and inhibited by cortisol is a 30 kDa form of u-PA. Although less prominent, t-PA and a 48 kDa form of u-PA follow a similar pattern of induction and inhibition; (2) changes in u-PA activity in response to castration and cortisol treatment are due to alterations in the level of u-PA mRNA and protein rather than in the activity of PAI-1; (3) not all castration-induced proteinases in the prostate are inhibited by cortisol.

Project description:Bradykinin causes vasodilation, stimulates tissue-type plasminogen activator (t-PA) release and, in rodents, increases muscle glucose uptake. Although bradykinin causes vasodilation partly by activating nitric-oxide synthase (NOS), the role of nitric oxide in regulating bradykinin-stimulated t-PA release is uncertain. This study examined the effect of high-dose NOS inhibition on bradykinin-stimulated t-PA release and glucose uptake in humans. We studied 24 healthy (12 women and 12 men), overweight and obese (body mass index >25 kg/m(2)), normotensive, nondiabetic subjects with normal cholesterol. We measured the effect of intra-arterial N(omega)-monomethyl-L-arginine (L-NMMA, 12 micromol/min) on forearm blood flow (FBF), net t-PA release, and glucose uptake at baseline and in response to intra-arterial bradykinin (50-200 ng/min) in subjects pretreated with the cyclooxygenase inhibitor aspirin. Measurements were repeated after isosorbide dinitrate (ISDN; 5 mg) or sildenafil (50 mg). L-NMMA decreased baseline FBF (P < 0.001), increased baseline forearm vascular resistance (P < 0.001), and increased the t-PA arterial-venous gradient (P = 0.04) without affecting baseline net t-PA release or glucose uptake. During L-NMMA, ISDN tended to decrease baseline net t-PA release (P = 0.06). L-NMMA blunted bradykinin-stimulated vasodilation (P < 0.001 for FBF and FVR). Bradykinin increased net glucose extraction (from -80 +/- 23 to -320 +/- 97 microg/min/100 ml at 200 ng/min bradykinin, P = 0.02), and L-NMMA (-143 +/- 50 microg/min/100 ml at 200 ng/min, P = 0.045) attenuated this effect. In contrast, L-NMMA enhanced bradykinin-stimulated t-PA release (39.9 +/- 7.0 ng/min/100 ml versus 30.0 +/- 4.2 ng/min/100 ml at 200 ng/min, P = 0.04 for L-NMMA). In gender-stratified analyses, L-NMMA significantly increased bradykinin-stimulated t-PA release in women (F = 6.7, P = 0.02) but not in men. Endogenous NO contributes to bradykinin-stimulated vasodilation and glucose uptake but attenuates the fibrinolytic response to exogenous bradykinin.

Dataset Information

Activities of wild-type and variant tissue-type plasminogen activators retained on vascular endothelial cells.

Publications

Activities of wild-type and variant tissue-type plasminogen activators retained on vascular endothelial cells.

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