The role of tissue-type plasminogen activator A-chain domains in plasma clearance

Browne, Michael; Chapman, C.G.; Dodd, Ian B.; Reavy, B.; Esmail, A.F.; Robinson, Jan

doi:10.1016/0268-9499(89)90048-9

Cited by 19 publications

(5 citation statements)

References 20 publications

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“…The slower plasma clearance of BM 06.022 might be explained by the fact BM 06.022 lacks mannose-rich carbohydrate chain in the first kringle, which is associated with a fast, mannose-specific uptake in liver endothelial cells (3,4,31-34). The longer plasma half-life for BM 06.022 is also in agreement with data on t-PA mutants that indicated that the finger and/or growth factor domain is associated with the rapid plasma clearance of t-PA (10)(11)(12)32,(35)(36)(37)(38).…”

Section: Discussionsupporting

confidence: 85%

Uptake, Internalization and Degradation of the Novel Plasminogen Activator Reteplase (BM 06.022) in the Rat

Kuiper¹,

Bilt²,

Berkel³

1995

Thromb Haemost

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SummaryThe catabolism of the novel plasminogen activator reteplase (BM 06.022) was described. For this purpose BM 06.022 was radiolabelled with l25I or with the accumulating label l25I-tyramine cellobiose (l25I-TC).BM 06.022 was injected at a pharmacological dose of 380 μg/kg b.w. and it was cleared from the plasma in a biphasic manner with a half-life of about 1 min in the α-phase and t1/2of 20-28 min in the β-phase. 28% and 72% of the injected dose was cleared in the α-phase and β-phase, respectively. Initially liver, kidneys, skin, bones, lungs, spleen, and muscles contributed mainly to the plasma clearance. Only liver and the kidneys, however, were responsible for the uptake and subsequent degradation of BM 06.022 and contributed for 75% to the catabolism of BM 06.022. BM 06.022 was degraded in the lysosomal compartment of both organs. Parenchymal liver cells were responsible for 70% of the liver uptake of BM 06.022. BM 06.022 associated rapidly to isolated rat parenchymal liver cells and was subsequently degraded in the lysosomal compartment of these cells. BM 06.022 bound with low-affinity to the parenchymal liver cells (550 nM) and the binding of BM 06.022 could be displaced by t-PA (IC50 5.6 nM), indicating that the low-density lipoprotein receptor-related protein (LRP) could be involved in the binding of BM 06.022. GST-RAP, which is an inhibitor of LRP, could in vivo significantly inhibit the uptake of BM 06.022 in the liver.It is concluded that BM 06.022 is metabolized primarily in the liver and the kidneys. These organs take up and degrade BM 06.022 in the lysosomes. The uptake mechanism of BM 06.022 in the kidneys is unknown, while LRP is responsible for a low-affinity binding and uptake of BM 06.022 in parenchymal liver cells.

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Section: Discussionsupporting

confidence: 85%

Uptake, Internalization and Degradation of the Novel Plasminogen Activator Reteplase (BM 06.022) in the Rat

Kuiper¹,

Bilt²,

Berkel³

1995

Thromb Haemost

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“…In addition, it was found that GK " K # P, like control t-PA, also bound to parenchymal cells in a Ca# + -dependent manner, which may indicate that the G domain is important for the optimal binding of t-PA to rat parenchymal liver cells. This observation is in agreement with observations on the importance of the G-domain in plasma clearance [28,53,55,56] and more specifically the importance of Tyr-67 in the binding to rat hepatoma cells H4 [61]. In contrast, the binding of several other t-PA mutants to the human hepatoma cell line HepG2 resulted from the interaction between the P domain and PAI-1, which is present in the extracellular matrix of HepG2 cells [32][33][34][35].…”

Section: Discussionsupporting

confidence: 92%

“…The most striking difference with the plasma clearance of control t-PA was a significantly longer plasma half-life for the three t-PA mutants studied. The longer plasma half-life is in agreement with data on t-PA mutants that indicate that the F and\or G domain may be associated with the rapid plasma clearance of t-PA [24,[53][54][55][56]. Little evidence could however be obtained for the specific involvement of the F or G domain, since both FK " K # P and GK " K # P were cleared from the plasma with comparable kinetics.…”

Section: Discussionsupporting

confidence: 82%

Interaction of mutants of tissue-type plasminogen activator with liver cells: effect of domain deletions

Kuiper¹,

Hof²,

Otter³

et al. 1996

Biochemical Journal

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The fibrin-specific thrombolyticum tissue-type plasminogen activator (t-PA) has proven to be a potent drug in several clinical trials, but its clinical application is complicated by the rapid clearance of t-PA from the circulation. The rapid plasma clearance of t-PA results from the uptake of t-PA in the liver. t-PA consists of several domains which may be involved in the interaction with the liver. Three domain-deletion mutants, which were produced by the use of a cassette gene system, were studied in vivo and in vitro for their capacity to bind to the various types of rat liver cells. The three mutants lacked, in comparison to control t-PA, the epidermal growth factor (G) domain, the finger (F) domain or the G domain plus the first kringle (K1). The plasma clearance of the three mutants was slower than that of control t-PA. The slower plasma clearance resulted from a decreased liver uptake: 50 and 80% for t-PA mutants and control t-PA respectively. It was found that the K1 domain was of major importance for the uptake of t-PA by liver endothelial cells in vivo and in vitro. The high-affinity binding of t-PA (and t-PA mutants) to parenchymal liver cells depended largely on the presence of the G domain. Other domain(s), like the F, K2 or protease domain, may be responsible for low-affinity, t-PA-specific binding to rat parenchymal liver cells.

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“…The aim of the present study was to obtain a mutant with a slow clearance in vivo and a high affinity for fibrin. Since t-PA is recognized by the liver primarily through the heavy chain (23,24), many mutants have been designed to evaluate the structural and functional relationships of t-PA by removing specific structural domains of the heavy chain (7,9,12,25). Among them, t-PA mutants containing deletion of the finger domain have a greatly prolonged half-life in vivo but tend to be accompanied by a decrease in affinity for fibrin and in fibrinolytic activity.…”

Section: Discussionmentioning

confidence: 99%

Recombinant Variants of Tissue-Type Plasminogen Activator Containing Amino Acid Substitutions in the Finger Domain

et al. 1992

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SummaryTissue-type plasminogen activator (t-PA) is a fibrin-specific agent which has been used to treat acute myocardial infarction. In an attempt to clarify the determinants for its rapid clearance in vivo and high affinity for fibrin clots, we produced five variants containing amino acid substitutions in the finger domain, at amino acid residues 7–9, 10–14, 15–19, 28–33, and 37–42. All the variants had a prolonged half-life and a decreased affinity for fibrin of various degrees. The 37–42 variant demonstrated about a 6-fold longer half-life with a lower affinity for fibrin. Human plasma clot lysis assay estimated the fibrinolytic activity of the 37–42 variant to be 1.4-fold less effective than that of the wild-type rt-PA. In a rabbit jugular vein clot lysis model, doses of 1.0 and 0.15 mg/kg were required for about 70% lysis in the wild-type and 37–42 variant, respectively. Fibrinogen was degraded only when the wild-type rt-PA was administered at a dose of 1.0 mg/kg. These findings suggest that the 37–42 variant can be employed at a lower dosage and that it is a more fibrin-specific thrombolytic agent than the wild-type rt-PA.

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The role of tissue-type plasminogen activator A-chain domains in plasma clearance

Cited by 19 publications

References 20 publications

Uptake, Internalization and Degradation of the Novel Plasminogen Activator Reteplase (BM 06.022) in the Rat

Uptake, Internalization and Degradation of the Novel Plasminogen Activator Reteplase (BM 06.022) in the Rat

Interaction of mutants of tissue-type plasminogen activator with liver cells: effect of domain deletions

Recombinant Variants of Tissue-Type Plasminogen Activator Containing Amino Acid Substitutions in the Finger Domain

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