1
|
Höllerer S, Jeschek M. Ultradeep characterisation of translational sequence determinants refutes rare-codon hypothesis and unveils quadruplet base pairing of initiator tRNA and transcript. Nucleic Acids Res 2023; 51:2377-2396. [PMID: 36727459 PMCID: PMC10018350 DOI: 10.1093/nar/gkad040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 12/05/2022] [Accepted: 01/13/2023] [Indexed: 02/03/2023] Open
Abstract
Translation is a key determinant of gene expression and an important biotechnological engineering target. In bacteria, 5'-untranslated region (5'-UTR) and coding sequence (CDS) are well-known mRNA parts controlling translation and thus cellular protein levels. However, the complex interaction of 5'-UTR and CDS has so far only been studied for few sequences leading to non-generalisable and partly contradictory conclusions. Herein, we systematically assess the dynamic translation from over 1.2 million 5'-UTR-CDS pairs in Escherichia coli to investigate their collective effect using a new method for ultradeep sequence-function mapping. This allows us to disentangle and precisely quantify effects of various sequence determinants of translation. We find that 5'-UTR and CDS individually account for 53% and 20% of variance in translation, respectively, and show conclusively that, contrary to a common hypothesis, tRNA abundance does not explain expression changes between CDSs with different synonymous codons. Moreover, the obtained large-scale data provide clear experimental evidence for a base-pairing interaction between initiator tRNA and mRNA beyond the anticodon-codon interaction, an effect that is often masked for individual sequences and therefore inaccessible to low-throughput approaches. Our study highlights the indispensability of ultradeep sequence-function mapping to accurately determine the contribution of parts and phenomena involved in gene regulation.
Collapse
Affiliation(s)
- Simon Höllerer
- Department of Biosystems Science and Engineering, Swiss Federal Institute of Technology – ETH Zurich, Basel CH-4058, Switzerland
| | - Markus Jeschek
- To whom correspondence should be addressed. Tel: +49 941 943 3161; Fax: +49 941 943 2403;
| |
Collapse
|
2
|
Vornholt T, Christoffel F, Pellizzoni MM, Panke S, Ward TR, Jeschek M. Systematic engineering of artificial metalloenzymes for new-to-nature reactions. Sci Adv 2021; 7:eabe4208. [PMID: 33523952 DOI: 10.1126/sciadv.abe4208] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 12/04/2020] [Indexed: 06/12/2023]
Abstract
Artificial metalloenzymes (ArMs) catalyzing new-to-nature reactions could play an important role in transitioning toward a sustainable economy. While ArMs have been created for various transformations, attempts at their genetic optimization have been case specific and resulted mostly in modest improvements. To realize their full potential, methods to rapidly discover active ArM variants for ideally any reaction of interest are required. Here, we introduce a reaction-independent, automation-compatible platform, which relies on periplasmic compartmentalization in Escherichia coli to rapidly and reliably engineer ArMs based on the biotin-streptavidin technology. We systematically assess 400 ArM mutants for five bioorthogonal transformations involving different metals, reaction mechanisms, and reactants, which include novel ArMs for gold-catalyzed hydroamination and hydroarylation. Activity enhancements up to 15-fold highlight the potential of the systematic approach. Furthermore, we suggest smart screening strategies and build machine learning models that accurately predict ArM activity from sequence, which has crucial implications for future ArM development.
Collapse
Affiliation(s)
- Tobias Vornholt
- Department of Biosystems Science and Engineering, ETH Zurich, CH-4058 Basel, Switzerland
- National Centre of Competence in Research (NCCR) Molecular Systems Engineering, Basel, Switzerland
| | - Fadri Christoffel
- National Centre of Competence in Research (NCCR) Molecular Systems Engineering, Basel, Switzerland
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, CH-4002 Basel, Switzerland
| | - Michela M Pellizzoni
- National Centre of Competence in Research (NCCR) Molecular Systems Engineering, Basel, Switzerland
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, CH-4002 Basel, Switzerland
| | - Sven Panke
- Department of Biosystems Science and Engineering, ETH Zurich, CH-4058 Basel, Switzerland
- National Centre of Competence in Research (NCCR) Molecular Systems Engineering, Basel, Switzerland
| | - Thomas R Ward
- National Centre of Competence in Research (NCCR) Molecular Systems Engineering, Basel, Switzerland
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, CH-4002 Basel, Switzerland
| | - Markus Jeschek
- Department of Biosystems Science and Engineering, ETH Zurich, CH-4058 Basel, Switzerland.
- National Centre of Competence in Research (NCCR) Molecular Systems Engineering, Basel, Switzerland
| |
Collapse
|
3
|
Höllerer S, Papaxanthos L, Gumpinger AC, Fischer K, Beisel C, Borgwardt K, Benenson Y, Jeschek M. Large-scale DNA-based phenotypic recording and deep learning enable highly accurate sequence-function mapping. Nat Commun 2020; 11:3551. [PMID: 32669542 PMCID: PMC7363850 DOI: 10.1038/s41467-020-17222-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 06/13/2020] [Indexed: 01/23/2023] Open
Abstract
Predicting effects of gene regulatory elements (GREs) is a longstanding challenge in biology. Machine learning may address this, but requires large datasets linking GREs to their quantitative function. However, experimental methods to generate such datasets are either application-specific or technically complex and error-prone. Here, we introduce DNA-based phenotypic recording as a widely applicable, practicable approach to generate large-scale sequence-function datasets. We use a site-specific recombinase to directly record a GRE's effect in DNA, enabling readout of both sequence and quantitative function for extremely large GRE-sets via next-generation sequencing. We record translation kinetics of over 300,000 bacterial ribosome binding sites (RBSs) in >2.7 million sequence-function pairs in a single experiment. Further, we introduce a deep learning approach employing ensembling and uncertainty modelling that predicts RBS function with high accuracy, outperforming state-of-the-art methods. DNA-based phenotypic recording combined with deep learning represents a major advance in our ability to predict function from genetic sequence.
Collapse
Affiliation(s)
- Simon Höllerer
- Department of Biosystems Science and Engineering, ETH Zurich, 4058, Basel, Switzerland
| | - Laetitia Papaxanthos
- Department of Biosystems Science and Engineering, ETH Zurich, 4058, Basel, Switzerland
- Swiss Institute of Bioinformatics, 4058, Basel, Switzerland
| | - Anja Cathrin Gumpinger
- Department of Biosystems Science and Engineering, ETH Zurich, 4058, Basel, Switzerland
- Swiss Institute of Bioinformatics, 4058, Basel, Switzerland
| | - Katrin Fischer
- Department of Biosystems Science and Engineering, ETH Zurich, 4058, Basel, Switzerland
| | - Christian Beisel
- Department of Biosystems Science and Engineering, ETH Zurich, 4058, Basel, Switzerland
| | - Karsten Borgwardt
- Department of Biosystems Science and Engineering, ETH Zurich, 4058, Basel, Switzerland.
- Swiss Institute of Bioinformatics, 4058, Basel, Switzerland.
| | - Yaakov Benenson
- Department of Biosystems Science and Engineering, ETH Zurich, 4058, Basel, Switzerland.
| | - Markus Jeschek
- Department of Biosystems Science and Engineering, ETH Zurich, 4058, Basel, Switzerland.
| |
Collapse
|
4
|
Vornholt T, Jeschek M. The Quest for Xenobiotic Enzymes: From New Enzymes for Chemistry to a Novel Chemistry of Life. Chembiochem 2020; 21:2241-2249. [PMID: 32294286 DOI: 10.1002/cbic.202000121] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/13/2020] [Indexed: 12/19/2022]
Abstract
Enzyme engineering has made impressive progress in the past decades, paving the way for the widespread use of enzymes for various purposes. In contrast to "classical" enzyme engineering, which focuses on optimizing specific properties of natural enzymes, a more recent trend towards the creation of artificial enzymes that catalyze fundamentally distinct, new-to-nature reactions is observable. While approaches for creating such enzymes differ significantly, they share the common goal of enabling biocatalytic novelty to broaden the range of applications for enzymes. Although most artificial enzymes reported to date are only moderately active and barely function in vivo, they have the potential to endow cells with capabilities that were previously out of reach and thus herald a new wave of "functional xenobiology". Herein, we highlight recent developments in the field of artificial enzymes with a particular focus on challenges and opportunities for their use in xenobiology.
Collapse
Affiliation(s)
- Tobias Vornholt
- Department of Biosystems Science and Engineering ETH Zürich, Mattenstrasse 26, 4058, Basel, Switzerland
| | - Markus Jeschek
- Department of Biosystems Science and Engineering ETH Zürich, Mattenstrasse 26, 4058, Basel, Switzerland
| |
Collapse
|
5
|
Heinisch T, Schwizer F, Garabedian B, Csibra E, Jeschek M, Vallapurackal J, Pinheiro VB, Marlière P, Panke S, Ward TR. Correction: E. coli surface display of streptavidin for directed evolution of an allylic deallylase. Chem Sci 2019; 10:6735. [PMID: 31367329 PMCID: PMC6625488 DOI: 10.1039/c9sc90139f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 06/19/2019] [Indexed: 12/03/2022] Open
Abstract
Correction for ‘E. coli surface display of streptavidin for directed evolution of an allylic deallylase’ by Tillmann Heinisch et al., Chem. Sci., 2018, 9, 5383–5388.
Collapse
Affiliation(s)
- Tillmann Heinisch
- Department of Chemistry , University of Basel , Mattenstrasse 24a , Basel CH-4002 , Switzerland .
| | - Fabian Schwizer
- Department of Chemistry , University of Basel , Mattenstrasse 24a , Basel CH-4002 , Switzerland .
| | - Brett Garabedian
- Department of Chemistry , University of Basel , Mattenstrasse 24a , Basel CH-4002 , Switzerland .
| | - Eszter Csibra
- Institute of Structural and Molecular Biology , University College London , Gower Street , London , WC1E 6BT , UK
| | - Markus Jeschek
- Department of Biosystems Science and Engineering , ETH Zurich , Mattenstrasse 26 , Basel CH-4058 , Switzerland
| | - Jaicy Vallapurackal
- Department of Chemistry , University of Basel , Mattenstrasse 24a , Basel CH-4002 , Switzerland .
| | - Vitor B Pinheiro
- Institute of Structural and Molecular Biology , University College London , Gower Street , London , WC1E 6BT , UK
| | | | - Sven Panke
- Department of Biosystems Science and Engineering , ETH Zurich , Mattenstrasse 26 , Basel CH-4058 , Switzerland
| | - Thomas R Ward
- Department of Chemistry , University of Basel , Mattenstrasse 24a , Basel CH-4002 , Switzerland .
| |
Collapse
|
6
|
Heinisch T, Schwizer F, Garabedian B, Csibra E, Jeschek M, Vallapurackal J, Pinheiro VB, Marlière P, Panke S, Ward TR. E. coli surface display of streptavidin for directed evolution of an allylic deallylase. Chem Sci 2018; 9:5383-5388. [PMID: 30079176 PMCID: PMC6048633 DOI: 10.1039/c8sc00484f] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 05/22/2018] [Indexed: 11/21/2022] Open
Abstract
Artificial metalloenzymes (ArMs hereafter) combine attractive features of both homogeneous catalysts and enzymes and offer the potential to implement new-to-nature reactions in living organisms. Herein we present an E. coli surface display platform for streptavidin (Sav hereafter) relying on an Lpp-OmpA anchor. The system was used for the high throughput screening of a bioorthogonal CpRu-based artificial deallylase (ADAse) that uncages an allylcarbamate-protected aminocoumarin 1. Two rounds of directed evolution afforded the double mutant S112M-K121A that displayed a 36-fold increase in surface activity vs. cellular background and a 5.7-fold increased in vitro activity compared to the wild type enzyme. The crystal structure of the best ADAse reveals the importance of mutation S112M to stabilize the cofactor conformation inside the protein.
Collapse
Affiliation(s)
- Tillmann Heinisch
- Department of Chemistry , University of Basel , Mattenstrasse 24a , Basel CH-4002 , Switzerland .
| | - Fabian Schwizer
- Department of Chemistry , University of Basel , Mattenstrasse 24a , Basel CH-4002 , Switzerland .
| | - Brett Garabedian
- Department of Chemistry , University of Basel , Mattenstrasse 24a , Basel CH-4002 , Switzerland .
| | - Eszter Csibra
- Institute of Structural and Molecular Biology , University College London , Gower Street , London , WC1E 6BT , UK
| | - Markus Jeschek
- Department of Biosystems Science and Engineering , ETH Zurich , Mattenstrasse 26 , Basel CH-4058 , Switzerland
| | - Jaicy Vallapurackal
- Department of Chemistry , University of Basel , Mattenstrasse 24a , Basel CH-4002 , Switzerland .
| | - Vitor B Pinheiro
- Institute of Structural and Molecular Biology , University College London , Gower Street , London , WC1E 6BT , UK
| | | | - Sven Panke
- Department of Biosystems Science and Engineering , ETH Zurich , Mattenstrasse 26 , Basel CH-4058 , Switzerland
| | - Thomas R Ward
- Department of Chemistry , University of Basel , Mattenstrasse 24a , Basel CH-4002 , Switzerland .
| |
Collapse
|
7
|
Weyrich A, Jeschek M, Schrapers KT, Lenz D, Chung TH, Rübensam K, Yasar S, Schneemann M, Ortmann S, Jewgenow K, Fickel J. Diet changes alter paternally inherited epigenetic pattern in male Wild guinea pigs. Environ Epigenet 2018; 4:dvy011. [PMID: 29992049 PMCID: PMC6031029 DOI: 10.1093/eep/dvy011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/19/2018] [Accepted: 04/06/2018] [Indexed: 05/14/2023]
Abstract
Epigenetic modifications, of which DNA methylation is the most stable, are a mechanism conveying environmental information to subsequent generations via parental germ lines. The paternal contribution to adaptive processes in the offspring might be crucial, but has been widely neglected in comparison to the maternal one. To address the paternal impact on the offspring's adaptability to changes in diet composition, we investigated if low protein diet (LPD) in F0 males caused epigenetic alterations in their subsequently sired sons. We therefore fed F0 male Wild guinea pigs with a diet lowered in protein content (LPD) and investigated DNA methylation in sons sired before and after their father's LPD treatment in both, liver and testis tissues. Our results point to a 'heritable epigenetic response' of the sons to the fathers' dietary change. Because we detected methylation changes also in the testis tissue, they are likely to be transmitted to the F2 generation. Gene-network analyses of differentially methylated genes in liver identified main metabolic pathways indicating a metabolic reprogramming ('metabolic shift'). Epigenetic mechanisms, allowing an immediate and inherited adaptation may thus be important for the survival of species in the context of a persistently changing environment, such as climate change.
Collapse
Affiliation(s)
- A Weyrich
- Leibniz-Institute for Zoo and Wildlife Research (IZW), Alfred-Kowalke-Street 17, D-10315 Berlin, Germany
| | - M Jeschek
- Leibniz-Institute for Zoo and Wildlife Research (IZW), Alfred-Kowalke-Street 17, D-10315 Berlin, Germany
- Berlin Center for Genomics in Biodiversity Research, Koenigin-Luise-Street 6-8, 14195 Berlin, Germany
| | - K T Schrapers
- Leibniz-Institute for Zoo and Wildlife Research (IZW), Alfred-Kowalke-Street 17, D-10315 Berlin, Germany
| | - D Lenz
- Leibniz-Institute for Zoo and Wildlife Research (IZW), Alfred-Kowalke-Street 17, D-10315 Berlin, Germany
| | - T H Chung
- Zymoresearch, EpiQuest, 17062 Murphy Avenue, Irvine, CA 92614, USA
| | - K Rübensam
- Leibniz-Institute for Zoo and Wildlife Research (IZW), Alfred-Kowalke-Street 17, D-10315 Berlin, Germany
| | - S Yasar
- Leibniz-Institute for Zoo and Wildlife Research (IZW), Alfred-Kowalke-Street 17, D-10315 Berlin, Germany
| | - M Schneemann
- Leibniz-Institute for Zoo and Wildlife Research (IZW), Alfred-Kowalke-Street 17, D-10315 Berlin, Germany
| | - S Ortmann
- Leibniz-Institute for Zoo and Wildlife Research (IZW), Alfred-Kowalke-Street 17, D-10315 Berlin, Germany
| | - K Jewgenow
- Leibniz-Institute for Zoo and Wildlife Research (IZW), Alfred-Kowalke-Street 17, D-10315 Berlin, Germany
| | - J Fickel
- Leibniz-Institute for Zoo and Wildlife Research (IZW), Alfred-Kowalke-Street 17, D-10315 Berlin, Germany
- Institute for Biochemistry and Biology, Potsdam University, Karl-Liebknecht-Street 24-25, 14476 Potsdam, Germany
| |
Collapse
|
8
|
Jeschek M, Panke S, Ward TR. Artificial Metalloenzymes on the Verge of New-to-Nature Metabolism. Trends Biotechnol 2017; 36:60-72. [PMID: 29061328 DOI: 10.1016/j.tibtech.2017.10.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/29/2017] [Accepted: 10/02/2017] [Indexed: 01/13/2023]
Abstract
Residing at the interface of chemistry and biotechnology, artificial metalloenzymes (ArMs) offer an attractive technology to combine the versatile reaction repertoire of transition metal catalysts with the exquisite catalytic features of enzymes. While earlier efforts in this field predominantly comprised studies in well-defined test-tube environments, a trend towards exploiting ArMs in more complex environments has recently emerged. Integration of these artificial biocatalysts in enzymatic cascades and using them in whole-cell biotransformations and in vivo opens up entirely novel prospects for both preparative chemistry and synthetic biology. We highlight selected recent developments with a particular focus on challenges and opportunities in the in vivo application of ArMs.
Collapse
Affiliation(s)
- Markus Jeschek
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich, Basel, Switzerland.
| | - Sven Panke
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich, Basel, Switzerland
| | - Thomas R Ward
- Department of Chemistry, University of Basel, Basel, Switzerland
| |
Collapse
|
9
|
Jeschek M, Bahls MO, Schneider V, Marlière P, Ward TR, Panke S. Biotin-independent strains of Escherichia coli for enhanced streptavidin production. Metab Eng 2017; 40:33-40. [DOI: 10.1016/j.ymben.2016.12.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/13/2016] [Accepted: 12/26/2016] [Indexed: 11/16/2022]
|
10
|
|
11
|
Sametz W, Jeschek M, Juan H, Wintersteiger R. Influence of polyunsaturated fatty acids on vasoconstrictions induced by 8-iso-PGF(2alpha) and 8-iso-PGE(2). Pharmacology 2000; 60:155-60. [PMID: 10754452 DOI: 10.1159/000028360] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
8-iso-PGF(2alpha) and 8-iso-PGE(2), which are released in vivo by free radical catalyzed peroxidation of arachidonic acid, are equipotent vasoconstrictors in vivo and in vitro. It is assumed that they exert this effect via activation of the thromboxane A(2) (TP) receptor or a TP-receptor-like isoprostane receptor. Increased levels of 8-iso-PGF(2alpha) have been detected in human cardiovascular diseases. It has been found that polyunsaturated fatty acids (PUFAs) have many beneficial effects in cardiovascular diseases, including antivasoconstrictor actions. Therefore, we investigated the influence of perfusions with eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and dihomo-gamma-linolenic acid (DGLA) at final concentrations of 3 and 30 micromol/l on vasoconstriction induced by 8-iso-PGF(2alpha), 8-iso-PGE(2) and the thromboxane A(2) mimetic U 46619 in the vasculature of the isolated perfused rabbit ear. Additionally, the effect of indomethacin (final concentration 3 micromol/l) on the effects of the PUFAs was investigated. Our results show that the PUFAs at a concentration of 30 micromol/l caused a significant inhibition of the vasoconstrictions induced by 8-iso-PGF(2alpha), 8-iso-PGE(2) and U 46619. Furthermore, it can be assumed that a part of the inhibitory effect of DGLA is due to the effect of a cyclooxygenase product, probably PGE(1), because indomethacin reduced the inhibitory effect of DGLA.
Collapse
Affiliation(s)
- W Sametz
- Department of Biomedical Research, University of Graz, Austria.
| | | | | | | |
Collapse
|
12
|
Harenberg J, Jeschek M, Acker M, Malsch R, Huhle G, Heene DL. Effects of low-molecular-weight dermatan sulfate on coagulation, fibrinolysis and tissue factor pathway inhibitor in healthy volunteers. Blood Coagul Fibrinolysis 1996; 7:49-56. [PMID: 8845462 DOI: 10.1097/00001721-199601000-00006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Low-molecular-weight (LMW)-dermatan sulfate (Desmin) with the mean molecular weight of 5600 Da has been obtained by limited depolymerization of natural dermatan sulfate. The pharmacokinetic and pharmacodynamic data of 100 and 200 mg were analyzed after intravenous injection and of 50, 100 and 200 mg after subcutaneous injection on tissue factor pathway inhibitor (TFPI) antigen and activity, heparin cofactor (HC) II activity, HeptestTM coagulation value, chromogenic S-2222 anti-factor Xa (aXa) assay, activated partial thromboplastin time (APTT), thrombin clotting time (TCT), plasminogen, tissue plasminogen activator activity (t-PA) and plasminogen activator inhibitor (PAI). After i.v.injection of 100 mg and 200 mg Desmin TFPI antigen and activity increased 2.2- and 2.7-fold, and returned to normal values within 60 and 90 min, respectively. Using the HC II assay the elimination half-lives (T1/2 el) increased from 1.9 h to 3.3 h with increasing doses of LMW-dermatan sulfate. T1/2 el were 4.3 and 6.9 h with the Heptest assay and 3.3 and 5.1 with the aXa method, respectively. APTT, TCT and the fibrinolytic parameters were not modified by either dose of i.v. LMW-dermatan sulfate. After s.c. administration of 100 mg or 200 mg LMW-dermatan sulfate no increase of TFPI antigen or activity was detected. T1/2 el was 5.6 h using HC II method, 11.1 h using Heptest and 7.8 h with the aXa activity. The total clearance was about ten-fold higher when determined by the HC II method compared with Heptest and aXa method. The volume of distribution (VD) increased with increasing doses of s.c. LMW-dermatan sulfate and was highest with the HC II method. Intravenous administration of 100 mg protamine chloride 15 min after i.v. dosing of 100 mg LMW-dermatan sulfate did not modify TFPI, coagulation or fibrinolytic parameters. Further analysis of the complex mechanism of action has to include studies which should explain the low release of TFPI in relation to the antithrombotic effects of LMW-dermatan sulfate.
Collapse
Affiliation(s)
- J Harenberg
- 1st Department of Medicine, Faculty of Clinical Medicine Mannheim, University of Heidelberg, Mannheim, Germany
| | | | | | | | | | | |
Collapse
|