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Dinglasan JLN, Sword TT, Barker JW, Doktycz MJ, Bailey CB. Investigating and Optimizing the Lysate-Based Expression of Nonribosomal Peptide Synthetases Using a Reporter System. ACS Synth Biol 2023; 12:1447-1460. [PMID: 37039644 PMCID: PMC11236431 DOI: 10.1021/acssynbio.2c00658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
Lysate-based cell-free expression (CFE) systems are accessible platforms for expressing proteins that are difficult to synthesize in vivo, such as nonribosomal peptide synthetases (NRPSs). NRPSs are large (>100 kDa), modular enzyme complexes that synthesize bioactive peptide natural products. This synthetic process is analogous to transcription/translation (TX/TL) in lysates, resulting in potential resource competition between NRPS expression and NRPS activity in cell-free environments. Moreover, CFE conditions depend on the size and structure of the protein. Here, a reporter system for rapidly investigating and optimizing reaction environments for NRPS CFE is described. This strategy is demonstrated in E. coli lysate reactions using blue pigment synthetase A (BpsA), a model NRPS, carrying a C-terminal tetracysteine (TC) tag which forms a fluorescent complex with the biarsenical dye, FlAsH. A colorimetric assay was adapted for lysate reactions to detect the blue pigment product, indigoidine, of cell-free expressed BpsA-TC, confirming that the tagged enzyme is catalytically active. An optimized protocol for end point TC/FlAsH complex measurements in reactions enables quick comparisons of full-length BpsA-TC expressed under different reaction conditions, defining unique requirements for NRPS expression that are related to the protein's catalytic activity and size. Importantly, these protein-dependent CFE conditions enable higher indigoidine titer and improve the expression of other monomodular NRPSs. Notably, these conditions differ from those used for the expression of superfolder GFP (sfGFP), a common reporter for optimizing lysate-based CFE systems, indicating the necessity for tailored reporters to optimize expression for specific enzyme classes. The reporter system is anticipated to advance lysate-based CFE systems for complex enzyme synthesis, enabling natural product discovery.
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Affiliation(s)
- Jaime Lorenzo N Dinglasan
- Graduate School of Genome Science & Technology, University of Tennessee-Knoxville, Knoxville, Tennessee 37996, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Tien T Sword
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, Tennessee 37996, United States
| | - J William Barker
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, Tennessee 37996, United States
| | - Mitchel J Doktycz
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Constance B Bailey
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, Tennessee 37996, United States
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Analysis of Virulence and Antimicrobial Resistance Gene Carriage in Staphylococcus aureus Infections in Equids Using Whole-Genome Sequencing. mSphere 2021; 6:e0019620. [PMID: 34346711 PMCID: PMC8386420 DOI: 10.1128/msphere.00196-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
While Staphylococcus aureus is associated with significant morbidity and mortality in equids (horses, donkeys, and mules), few studies have performed whole-genome sequencing to fully categorize large collections of equine isolates. Such sequencing allows for a comprehensive analysis of the genetic lineage and relationships of isolates, as well as the virulence genes present in each, which can be important for understanding the epidemiology of strains and their range of infections. Seventy-two clinical Staphylococcus aureus isolates from equids were collected at the Texas A&M University Veterinary Medical Teaching Hospital between 2007 and 2017. Whole-genome sequencing was performed to characterize the isolates according to sequence typing, biofilm association, antimicrobial resistance, and toxin gene carriage. Of the 72 isolates, 19% were methicillin resistant, of which the majority belonged to clonal complex 8. Eighteen distinct sequence types (STs) were represented, with the most common being ST1, ST133, ST8, and ST97. Most isolates had weak or negative overall biofilm production. Toxin and antimicrobial resistance gene carriage was varied; of note, this study revealed that a large proportion of North American equine isolates carry the leucocidin PQ toxin (66% of isolates). One isolate (17-021) carried genes imparting lincosamide and high-level mupirocin resistance, a combination not previously reported in equine-derived S. aureus isolates. IMPORTANCE This is one of the first studies to perform whole-genome sequencing (WGS) of a large collection of Staphylococcus aureus isolates, both methicillin resistant and susceptible, collected from horses. A large proportion of the isolates carry leucocidin PQ (LukPQ), making this one of the first reports of such carriage in the United States. The presence of lincosamide and high-level mupirocin resistance in a methicillin-susceptible S. aureus (MSSA) isolate highlights the importance of MSSA as a reservoir of important antimicrobial resistance genes. As microbial resistance genes on mobile genetic elements can pass between S. aureus strains and livestock-associated strains can be transferred to humans, these findings have important public health implications.
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Thrombin generation test based on a 96-channel pipettor for evaluation of FXIa procoagulant activity in pharmaceuticals. Nat Protoc 2021; 16:3981-4003. [PMID: 34215864 DOI: 10.1038/s41596-021-00568-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 05/04/2021] [Indexed: 02/06/2023]
Abstract
Thrombin generation (TG) assays are used widely to investigate both diseases and drugs that impact thrombosis and bleeding. TG assays were also instrumental in the identification of thrombogenic impurities in immune globulin products, which were associated with thrombotic adverse events in patients. TG assays are therefore now used by quality control laboratories of plasma derivative drug manufacturers and regulatory agencies responsible for the safety testing and release of immune globulin products. In this protocol, we describe a robust and sensitive version of the TG assay for quantitative measurement of thrombogenic activity in immune globulin products. Compared with the version of the assay commonly used in clinical laboratories that compares individual patient plasma samples with normal donor samples, our TG assay is suitable for quick (170-260 min) semiautomated analysis of multiple drug samples against the World Health Organization international standard for factor XIa. Commercially available reagents can be used for the assay, and it does not require specialized equipment. The protocol can be easily adapted for the measurement of the procoagulant activity of other biopharmaceuticals, e.g., coagulation factors.
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Liang Y, Jackson JW, Woodle SA, Surov SS, Parunov LA, Scott DE, Weinstein M, Lee TK, Ovanesov MV. Detecting factor XIa in immune globulin products: Commutability of international reference materials for traditional and global hemostasis assays. Res Pract Thromb Haemost 2021; 5:211-222. [PMID: 33537546 PMCID: PMC7845073 DOI: 10.1002/rth2.12467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/21/2020] [Accepted: 11/03/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Activated coagulation factor XIa (FXIa) is an impurity and primary source of procoagulant activity in thrombosis-implicated immune globulin (IG) products. Several assays, of varying quality and precision are used to assess FXIa-like procoagulant activity in units relevant to their respective principles. OBJECTIVES To advance unified reporting, we sought to employ the World Health Organization reference reagents (RRs) to present the results of differing methodologies in units of FXIa activity and rank the sensitivity and robustness of these methodologies. METHODS RR 11/236 served as a calibrator in several FXIa-sensitive blood coagulation tests: two commercial chromogenic FXIa assays (CAs); a nonactivated partial thromboplastin time (NaPTT); an in-house fibrin generation (FG) assay; an in-house thrombin generation (TG) assay; and an assay for FXIa- and kallikrein-like proteolytic activities based on cleavage of substrate SN13a. Some assays were tested in either normal or FXI-deficient plasma. RESULTS Each method demonstrated a sigmoidal dose-response to RRs. NaPTT was the least sensitive to FXIa and the least precise; our in-house TG was the most sensitive; and the two CAs were the most precise. All methods, except for SN13a, which is less specific for thrombotic impurities, gave comparable (within 20% difference) FXIa activity assignments for IG lots. CONCLUSIONS Purified FXIa reference standards support quantitation of FXIa levels in IG products in all tested assay methodologies. This should help to standardize the measurement of thrombotic potentials in IG products and prevent products exhibiting high procoagulant activity from distribution for patient use. Further research is needed to address the effect of IG product-specific matrixes on assay performance.
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Affiliation(s)
- Yideng Liang
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMDUSA
| | - Joseph W. Jackson
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMDUSA
| | - Samuel A. Woodle
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMDUSA
| | - Stepan S. Surov
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMDUSA
| | - Leonid A. Parunov
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMDUSA
| | - Dorothy E. Scott
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMDUSA
| | - Mark Weinstein
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMDUSA
| | - Timothy K. Lee
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMDUSA
| | - Mikhail V. Ovanesov
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMDUSA
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Xu Y, Liang Y, Parunov L, Despres D, Eckhaus M, Scott D, Ovanesov M, Struble EB. Combined thrombogenic effects of vessel injury, pregnancy and procoagulant immune globulin administration in mice. Thromb J 2020; 18:32. [PMID: 33292285 PMCID: PMC7648396 DOI: 10.1186/s12959-020-00245-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/26/2020] [Indexed: 11/25/2022] Open
Abstract
Background Pregnant women are at increased risk of thrombotic adverse events. Plasma derived immune globulin (IG) products, which are used in pregnancy for various indications, may contain procoagulant impurity activated coagulation factor XI (FXIa). Procoagulant IG products have been associated with increased thrombogenicity but their effect in pregnancy is unknown. Methods Late pregnant (gestation days 17–20) or early lactation (days 1–3) and control female mice were treated with IGs supplemented with human FXIa then subjected to ferric chloride (FeCl3) vessel injury. Occlusion of blood vessel was assessed by recording blood velocity in the femoral vein for 20 min using doppler ultrasound laser imaging. FXIa dose was selected by the ability to increase thrombin generation in mouse plasma in vitro. Results FXIa produced robust thrombin generation in mouse plasma ex vivo. Following FeCl3 injury, pregnant and non-pregnant mice receiving IG + FXIa exhibited faster reduction of blood velocity in femoral vein compared to IG alone or untreated controls. In vitro, thrombin generation in plasma samples collected after thrombosis in FXIa-treated animals was elevated and could be reduced by anti-FXI antibody. Conclusions Our results suggest that intravenously-administered FXIa may contribute to thrombosis at the site of vascular injury in both pregnant and non-pregnant animals. Supplementary Information Supplementary information accompanies this paper at 10.1186/s12959-020-00245-8.
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Affiliation(s)
- Yanqun Xu
- Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993-0002, USA
| | - Yideng Liang
- Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993-0002, USA
| | - Leonid Parunov
- Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993-0002, USA
| | - Daryl Despres
- Mouse Imaging Facility, National Institutes of Health, Bethesda, MD, USA
| | - Michael Eckhaus
- Pathology Service, Division of Veterinary Resources, National Institutes of Health, Bethesda, MD, USA
| | - Dorothy Scott
- Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993-0002, USA
| | - Mikhail Ovanesov
- Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993-0002, USA.
| | - Evi B Struble
- Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993-0002, USA.
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6
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Nechipurenko DY, Shibeko AM, Sveshnikova AN, Panteleev MA. In Silico Hemostasis Modeling and Prediction. Hamostaseologie 2020; 40:524-535. [PMID: 32916753 DOI: 10.1055/a-1213-2117] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Computational physiology, i.e., reproduction of physiological (and, by extension, pathophysiological) processes in silico, could be considered one of the major goals in computational biology. One might use computers to simulate molecular interactions, enzyme kinetics, gene expression, or whole networks of biochemical reactions, but it is (patho)physiological meaning that is usually the meaningful goal of the research even when a single enzyme is its subject. Although exponential rise in the use of computational and mathematical models in the field of hemostasis and thrombosis began in the 1980s (first for blood coagulation, then for platelet adhesion, and finally for platelet signal transduction), the majority of their successful applications are still focused on simulating the elements of the hemostatic system rather than the total (patho)physiological response in situ. Here we discuss the state of the art, the state of the progress toward the efficient "virtual thrombus formation," and what one can already get from the existing models.
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Affiliation(s)
- Dmitry Y Nechipurenko
- Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia.,Center for Theoretical Problems of Physicochemical Pharmacology of the Russian Academy of Sciences, Moscow, Russia.,Dmitry Rogachev National Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
| | - Aleksey M Shibeko
- Center for Theoretical Problems of Physicochemical Pharmacology of the Russian Academy of Sciences, Moscow, Russia.,Dmitry Rogachev National Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
| | - Anastasia N Sveshnikova
- Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia.,Center for Theoretical Problems of Physicochemical Pharmacology of the Russian Academy of Sciences, Moscow, Russia.,Dmitry Rogachev National Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
| | - Mikhail A Panteleev
- Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia.,Center for Theoretical Problems of Physicochemical Pharmacology of the Russian Academy of Sciences, Moscow, Russia.,Dmitry Rogachev National Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
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Novel Bead-Based Epitope Assay is a sensitive and reliable tool for profiling epitope-specific antibody repertoire in food allergy. Sci Rep 2019; 9:18425. [PMID: 31804555 PMCID: PMC6895130 DOI: 10.1038/s41598-019-54868-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 11/09/2019] [Indexed: 12/16/2022] Open
Abstract
Identification of allergenic IgE epitopes is instrumental for the development of novel diagnostic and prognostic methods in food allergy. In this work, we present the quantification and validation of a Bead-Based Epitope Assay (BBEA) that through multiplexing of epitopes and multiple sample processing enables completion of large experiments in a short period of time, using minimal quantities of patients’ blood. Peptides that are uniquely coupled to beads are incubated with serum or plasma samples, and after a secondary fluorophore-labeled antibody is added, the level of fluorescence is quantified with a Luminex reader. The signal is then normalized and converted to epitope-specific antibody binding values. We show that the effect of technical artifacts, i.e. well position or reading order, is minimal; and batch effects - different individual microplate runs - can be easily estimated and eliminated from the data. Epitope-specific antibody binding quantified with BBEA is highly reliable, reproducible and has greater sensitivity of epitope detection compared to peptide microarrays. IgE directed at allergenic epitopes is a sensitive biomarker of food allergy and can be used to predict allergy severity and phenotypes; and quantification of the relationship between epitope-specific IgE and IgG4 can further improve our understanding of the immune mechanisms behind allergic sensitization.
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8
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Singleton C, Gilman J, Rollit J, Zhang K, Parker DA, Love J. A design of experiments approach for the rapid formulation of a chemically defined medium for metabolic profiling of industrially important microbes. PLoS One 2019; 14:e0218208. [PMID: 31188885 PMCID: PMC6561596 DOI: 10.1371/journal.pone.0218208] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/28/2019] [Indexed: 12/30/2022] Open
Abstract
Geobacillus thermoglucosidans DSM2542 is an industrially important microbe, however the complex nutritional requirements of Geobacilli confound metabolic engineering efforts. Previous studies have utilised semi-defined media recipes that contain complex, undefined, biologically derived nutrients which have unknown ingredients that cannot be quantified during metabolic profiling. This study used design of experiments to investigate how individual nutrients and interactions between these nutrients contribute to growth. A mathematically derived defined medium has been formulated that has been shown to robustly support growth of G. thermoglucosidans in two different environmental conditions (96-well plate and shake flask) and with a variety of lignocellulose-based carbohydrates. This enabled the catabolism of industrially relevant carbohydrates to be investigated.
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Affiliation(s)
- Chloe Singleton
- The Exeter Microbial Biofuels Group, College of Life and Environmental Sciences, The University of Exeter, Exeter, Devon, United Kingdom
| | - James Gilman
- The Exeter Microbial Biofuels Group, College of Life and Environmental Sciences, The University of Exeter, Exeter, Devon, United Kingdom
| | - Jessica Rollit
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Kun Zhang
- Shell Technology Centre, Houston, Texas, United States of America
| | - David A. Parker
- The Exeter Microbial Biofuels Group, College of Life and Environmental Sciences, The University of Exeter, Exeter, Devon, United Kingdom
- Shell Technology Centre, Houston, Texas, United States of America
| | - John Love
- The Exeter Microbial Biofuels Group, College of Life and Environmental Sciences, The University of Exeter, Exeter, Devon, United Kingdom
- * E-mail:
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Gilman J, Singleton C, Tennant RK, James P, Howard TP, Lux T, Parker DA, Love J. Rapid, Heuristic Discovery and Design of Promoter Collections in Non-Model Microbes for Industrial Applications. ACS Synth Biol 2019; 8:1175-1186. [PMID: 30995831 DOI: 10.1021/acssynbio.9b00061] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Well-characterized promoter collections for synthetic biology applications are not always available in industrially relevant hosts. We developed a broadly applicable method for promoter identification in atypical microbial hosts that requires no a priori understanding of cis-regulatory element structure. This novel approach combines bioinformatic filtering with rapid empirical characterization to expand the promoter toolkit and uses machine learning to improve the understanding of the relationship between DNA sequence and function. Here, we apply the method in Geobacillus thermoglucosidasius, a thermophilic organism with high potential as a synthetic biology chassis for industrial applications. Bioinformatic screening of G. kaustophilus, G. stearothermophilus, G. thermodenitrificans, and G. thermoglucosidasius resulted in the identification of 636 100 bp putative promoters, encompassing the genome-wide design space and lacking known transcription factor binding sites. Eighty of these sequences were characterized in vivo, and activities covered a 2-log range of predictable expression levels. Seven sequences were shown to function consistently regardless of the downstream coding sequence. Partition modeling identified sequence positions upstream of the canonical -35 and -10 consensus motifs that were predicted to strongly influence regulatory activity in Geobacillus, and artificial neural network and partial least squares regression models were derived to assess if there were a simple, forward, quantitative method for in silico prediction of promoter function. However, the models were insufficiently general to predict pre hoc promoter activity in vivo, most probably as a result of the relatively small size of the training data set compared to the size of the modeled design space.
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Affiliation(s)
- James Gilman
- The BioEconomy Centre, Biosciences, College of Life and Environmental Sciences, Stocker Road, University of Exeter, Exeter EX4 4QD, U.K
| | - Chloe Singleton
- The BioEconomy Centre, Biosciences, College of Life and Environmental Sciences, Stocker Road, University of Exeter, Exeter EX4 4QD, U.K
| | - Richard K. Tennant
- The BioEconomy Centre, Biosciences, College of Life and Environmental Sciences, Stocker Road, University of Exeter, Exeter EX4 4QD, U.K
| | - Paul James
- The BioEconomy Centre, Biosciences, College of Life and Environmental Sciences, Stocker Road, University of Exeter, Exeter EX4 4QD, U.K
| | - Thomas P. Howard
- School of Natural and Environmental Sciences, Newcastle University, Devonshire Building, Newcastle-upon-Tyne NE1 7RU, U.K
| | - Thomas Lux
- Plant Genome and Systems Biology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Munich 85764, Germany
| | - David A. Parker
- Biodomain, Shell Technology Center Houston, 3333 Highway 6 South, Houston, Texas 77082-3101, United States
| | - John Love
- The BioEconomy Centre, Biosciences, College of Life and Environmental Sciences, Stocker Road, University of Exeter, Exeter EX4 4QD, U.K
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Modeling thrombosis in silico: Frontiers, challenges, unresolved problems and milestones. Phys Life Rev 2018; 26-27:57-95. [PMID: 29550179 DOI: 10.1016/j.plrev.2018.02.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/21/2018] [Accepted: 02/24/2018] [Indexed: 12/24/2022]
Abstract
Hemostasis is a complex physiological mechanism that functions to maintain vascular integrity under any conditions. Its primary components are blood platelets and a coagulation network that interact to form the hemostatic plug, a combination of cell aggregate and gelatinous fibrin clot that stops bleeding upon vascular injury. Disorders of hemostasis result in bleeding or thrombosis, and are the major immediate cause of mortality and morbidity in the world. Regulation of hemostasis and thrombosis is immensely complex, as it depends on blood cell adhesion and mechanics, hydrodynamics and mass transport of various species, huge signal transduction networks in platelets, as well as spatiotemporal regulation of the blood coagulation network. Mathematical and computational modeling has been increasingly used to gain insight into this complexity over the last 30 years, but the limitations of the existing models remain profound. Here we review state-of-the-art-methods for computational modeling of thrombosis with the specific focus on the analysis of unresolved challenges. They include: a) fundamental issues related to physics of platelet aggregates and fibrin gels; b) computational challenges and limitations for solution of the models that combine cell adhesion, hydrodynamics and chemistry; c) biological mysteries and unknown parameters of processes; d) biophysical complexities of the spatiotemporal networks' regulation. Both relatively classical approaches and innovative computational techniques for their solution are considered; the subjects discussed with relation to thrombosis modeling include coarse-graining, continuum versus particle-based modeling, multiscale models, hybrid models, parameter estimation and others. Fundamental understanding gained from theoretical models are highlighted and a description of future prospects in the field and the nearest possible aims are given.
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11
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Melhado-Kimura V, Bizzacchi JMA, Quaino SKP, Montalvao S, Bahamondes L, Fernandes A. Effect of the injectable contraceptive depot-medroxyprogesterone acetate on coagulation parameters in new users. J Obstet Gynaecol Res 2017; 43:1054-1060. [DOI: 10.1111/jog.13306] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 12/21/2016] [Accepted: 01/14/2017] [Indexed: 11/27/2022]
Affiliation(s)
| | | | | | - Silmara Montalvao
- Blood Center, School of Medical Sciences; University of Campinas; Campinas SP Brazil
| | - Luis Bahamondes
- Department of Obstetrics and Gynecology; University of Campinas; Campinas SP Brazil
| | - Arlete Fernandes
- Department of Obstetrics and Gynecology; University of Campinas; Campinas SP Brazil
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Abstract
Background: Dilution bias is a major cause of immunoassay variability due to the lack of an internal standard to determine the true versus the expected dilution value. Methodology: We used an internal control to measure dilution bias in an ELISA. Acridine-orange was added at the first dilution step and monitored throughout dilutions. Assay results were corrected using the fluorescent signal ratio between samples and reference. Acridine dilution correlated with analyte-specific assay measurements (R2 = 0.987). Correction of assay results with the measured dilution factor improved both accuracy and precision resulting in a reduction of >50% %CV reduction. Conclusion: Dilution correction can significantly improve accuracy and precision of immunoassays. Additional control strategies may further mitigate other sources of variability.
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Liew OW, Yandle TG, Chong JPC, Ng YX, Frampton CM, Ng TP, Lam CSP, Richards AM. High-Sensitivity Sandwich ELISA for Plasma NT-proUcn2: Plasma Concentrations and Relationship to Mortality in Heart Failure. Clin Chem 2016; 62:856-65. [DOI: 10.1373/clinchem.2015.252932] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/21/2016] [Indexed: 01/01/2023]
Abstract
Abstract
BACKGROUND
Urocortin 2 (Ucn2) has powerful hemodynamic, renal, and neurohormonal actions and likely participates in normal circulatory homeostasis and the compensatory response to heart failure (HF). A validated assay for endogenous circulating Ucn2 would facilitate investigations into Ucn2 physiology and elucidate its derangement and potential as a biomarker in heart disease.
METHOD
We developed a chemiluminescence-based sandwich ELISA to measure plasma N-terminal (NT)-proUcn2 in non-HF patients (control; n = 160) and HF patients with reduced (HFREF; n = 134) and preserved (HFPEF; n = 121) left ventricular ejection fraction (LVEF).
RESULTS
The ELISA had a limit of detection of 8.47 ng/L (1.52 pmol/L) and working range of 23.8–572 ng/L. Intra- and interassay CV and total error were 4.8, 16.2, and 17.7%, respectively. The median (interquartile range) plasma NT-proUcn2 concentration in controls was 112 (86–132) ng/L. HFREF, HFPEF, and all HF plasma concentrations were significantly increased [117 (98–141) ng/L, P = 0.0007; 119 (93–136) ng/L, P = 0.0376, and 119 (97–140) ng/L, P = 0.001] compared with controls but did not differ significantly between HFREF and HFPEF. NT-proUcn2 was modestly related to age (r = 0.264, P = 0.001) and cardiac troponin T (r = 0.258, P = 0.001) but not N-terminal pro-B-type natriuretic peptide, body mass index, LVEF, or estimated glomerular filtration rate. On multivariate analysis, plasma NT-proUcn2 was independently and inversely related to 2-year mortality in HF.
CONCLUSIONS
The validated ELISA measured human NT-proUcn2 in plasma and showed modest but significant increases in HF patients compared with controls. In HF, the unusual inverse relationship between plasma NT-proUcn2 and 2-year mortality portends potential prognostic value but requires further corroboration.
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Affiliation(s)
- Oi Wah Liew
- Cardiovascular Research Institute, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
| | - Timothy G Yandle
- Christchurch Heart Institute, University of Otago, Otago, New Zealand
| | - Jenny P C Chong
- Cardiovascular Research Institute, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
| | - Yan Xia Ng
- Cardiovascular Research Institute, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
| | | | - Tze Pin Ng
- Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
| | - Carolyn S P Lam
- Cardiovascular Research Institute, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
- Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
| | - A Mark Richards
- Cardiovascular Research Institute, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
- Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
- Christchurch Heart Institute, University of Otago, Otago, New Zealand
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Roselle C, Verch T, Shank-Retzlaff M. Mitigation of microtiter plate positioning effects using a block randomization scheme. Anal Bioanal Chem 2016; 408:3969-79. [DOI: 10.1007/s00216-016-9469-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/02/2016] [Accepted: 03/04/2016] [Indexed: 11/30/2022]
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15
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Jha NK, Shestopal SA, Gourley MJ, Woodle SA, Liang Y, Sarafanov AG, Weinstein M, Ovanesov MV. Optimization of the thrombin generation test components to measure potency of factor VIII concentrates. Haemophilia 2016; 22:780-9. [DOI: 10.1111/hae.12943] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2016] [Indexed: 02/06/2023]
Affiliation(s)
- N. K. Jha
- Office of Blood Research and Review Center for Biologics Evaluation and Research U.S. Food and Drug Administration Silver Spring MDUSA
- Department of Physics George Washington University Washington DC USA
| | - S. A. Shestopal
- Office of Blood Research and Review Center for Biologics Evaluation and Research U.S. Food and Drug Administration Silver Spring MDUSA
| | - M. J. Gourley
- Office of Blood Research and Review Center for Biologics Evaluation and Research U.S. Food and Drug Administration Silver Spring MDUSA
| | - S. A. Woodle
- Office of Blood Research and Review Center for Biologics Evaluation and Research U.S. Food and Drug Administration Silver Spring MDUSA
| | - Y. Liang
- Office of Blood Research and Review Center for Biologics Evaluation and Research U.S. Food and Drug Administration Silver Spring MDUSA
| | - A. G. Sarafanov
- Office of Blood Research and Review Center for Biologics Evaluation and Research U.S. Food and Drug Administration Silver Spring MDUSA
| | - M. Weinstein
- Office of Blood Research and Review Center for Biologics Evaluation and Research U.S. Food and Drug Administration Silver Spring MDUSA
| | - M. V. Ovanesov
- Office of Blood Research and Review Center for Biologics Evaluation and Research U.S. Food and Drug Administration Silver Spring MDUSA
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16
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Lachmann A, Giorgi FM, Alvarez MJ, Califano A. Detection and removal of spatial bias in multiwell assays. Bioinformatics 2016; 32:1959-65. [PMID: 27153732 DOI: 10.1093/bioinformatics/btw092] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 02/14/2016] [Indexed: 01/05/2023] Open
Abstract
MOTIVATION Multiplex readout assays are now increasingly being performed using microfluidic automation in multiwell format. For instance, the Library of Integrated Network-based Cellular Signatures (LINCS) has produced gene expression measurements for tens of thousands of distinct cell perturbations using a 384-well plate format. This dataset is by far the largest 384-well gene expression measurement assay ever performed. We investigated the gene expression profiles of a million samples from the LINCS dataset and found that the vast majority (96%) of the tested plates were affected by a significant 2D spatial bias. RESULTS Using a novel algorithm combining spatial autocorrelation detection and principal component analysis, we could remove most of the spatial bias from the LINCS dataset and show in parallel a dramatic improvement of similarity between biological replicates assayed in different plates. The proposed methodology is fully general and can be applied to any highly multiplexed assay performed in multiwell format. CONTACT ac2248@columbia.edu SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Alexander Lachmann
- Department of Biomedical Informatics (DBMI) Department of Systems Biology Center for Computational Biology and Bioinformatics (C2B2), Columbia University, New York, NY, USA
| | - Federico M Giorgi
- Department of Systems Biology Center for Computational Biology and Bioinformatics (C2B2), Columbia University, New York, NY, USA Scuola Superiore Sant'Anna, Pisa, Italy
| | | | - Andrea Califano
- Department of Biomedical Informatics (DBMI) Department of Systems Biology Center for Computational Biology and Bioinformatics (C2B2), Columbia University, New York, NY, USA Department of Biochemistry and Molecular Biophysics Institute for Cancer Genetics Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA
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17
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Parunov LA, Surov SS, Tucker E, Ovanesov MV. The effect of corn trypsin inhibitor and inhibiting antibodies for FXIa and FXIIa on coagulation of plasma and whole blood: comment. J Thromb Haemost 2015; 13:1527-30. [PMID: 26094623 DOI: 10.1111/jth.13028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- L A Parunov
- Office of Blood Research and Review, CBER, US Food and Drug Administration, Silver Spring, MD, USA
| | - S S Surov
- Office of Blood Research and Review, CBER, US Food and Drug Administration, Silver Spring, MD, USA
| | - E Tucker
- Oregon Health and Science University, Portland, OR, USA
| | - M V Ovanesov
- Office of Blood Research and Review, CBER, US Food and Drug Administration, Silver Spring, MD, USA
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18
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Germishuizen WA, Gyure DC, Stubbings D, Burnouf T. Quantifying the thrombogenic potential of human plasma-derived immunoglobulin products. Biologicals 2014; 42:260-70. [PMID: 25096922 DOI: 10.1016/j.biologicals.2014.04.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 04/24/2014] [Accepted: 04/29/2014] [Indexed: 12/27/2022] Open
Abstract
Polyvalent immunoglobulin G (IgG) products obtained by fractionation of human plasma are used to treat a broad range of conditions, including immunodeficiency syndromes and autoimmune, inflammatory, and infectious diseases. Recent incidences of increased thromboembolic events (TEEs) associated with intravenous (IV) IgG (IVIG) led to recalls of some products and increased regulatory oversight of manufacturing processes in order to ensure that products are essentially free of procoagulant/thrombogenic plasma protein contaminants. Laboratory investigations have now identified activated factor XI (FXIa) as the likely causative agent of IVIG-related TEEs. Quantification of the thrombogenic potential is becoming a requirement made to fractionators (a) to validate the capacity of IVIG and subcutaneous IgG manufacturing processes to remove procoagulant contaminants and (b) to establish the safety of the final products. However, in the absence of a recommended test by the main regulatory authorities, several analytical approaches have been evaluated by fractionators, regulators, and university groups. This review focuses on the scientific rationale, merits, and applications of several analytical methods of quantifying the thrombogenic potential of IgG products and intermediates to meet the latest regulatory requirements.
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Affiliation(s)
| | - D C Gyure
- National Bioproducts Institute, Pinetown, South Africa
| | - D Stubbings
- National Bioproducts Institute, Pinetown, South Africa
| | - T Burnouf
- Graduate Institute of Biomedical Materials and Tissue Engineering, Taipei Medical University, 250 Wuxing St., Taipei City 110, Taiwan.
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19
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Sridhar G, Ekezue BF, Izurieta HS, Selvam N, Ovanesov MV, Divan HA, Liang Y, Golding B, Forshee RA, Anderson SA, Menis M. Immune globulins and same-day thrombotic events as recorded in a large health care database during 2008 to 2012. Transfusion 2014; 54:2553-65. [DOI: 10.1111/trf.12663] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 02/03/2014] [Accepted: 02/25/2014] [Indexed: 01/01/2023]
Affiliation(s)
| | | | - Hector S. Izurieta
- Center for Biologics Evaluation and Research; US Food and Drug Administration; Rockville Maryland
| | | | - Mikhail V. Ovanesov
- Center for Biologics Evaluation and Research; US Food and Drug Administration; Rockville Maryland
| | | | - Yideng Liang
- Center for Biologics Evaluation and Research; US Food and Drug Administration; Rockville Maryland
| | - Basil Golding
- Center for Biologics Evaluation and Research; US Food and Drug Administration; Rockville Maryland
| | - Richard A. Forshee
- Center for Biologics Evaluation and Research; US Food and Drug Administration; Rockville Maryland
| | - Steven A. Anderson
- Center for Biologics Evaluation and Research; US Food and Drug Administration; Rockville Maryland
| | - Mikhail Menis
- Center for Biologics Evaluation and Research; US Food and Drug Administration; Rockville Maryland
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