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Sverdlov O, Curcic J, Hannesdottir K, Gou L, De Luca V, Ambrosetti F, Zhang B, Praestgaard J, Vallejo V, Dolman A, Gomez-Mancilla B, Biliouris K, Deurinck M, Cormack F, Anderson JJ, Bott NT, Peremen Z, Issachar G, Laufer O, Joachim D, Jagesar RR, Jongs N, Kas MJ, Zhuparris A, Zuiker R, Recourt K, Zuilhof Z, Cha JH, Jacobs GE. A Study of Novel Exploratory Tools, Digital Technologies, and Central Nervous System Biomarkers to Characterize Unipolar Depression. Front Psychiatry 2021; 12:640741. [PMID: 34025472 PMCID: PMC8136319 DOI: 10.3389/fpsyt.2021.640741] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 03/23/2021] [Indexed: 01/04/2023] Open
Abstract
Background: Digital technologies have the potential to provide objective and precise tools to detect depression-related symptoms. Deployment of digital technologies in clinical research can enable collection of large volumes of clinically relevant data that may not be captured using conventional psychometric questionnaires and patient-reported outcomes. Rigorous methodology studies to develop novel digital endpoints in depression are warranted. Objective: We conducted an exploratory, cross-sectional study to evaluate several digital technologies in subjects with major depressive disorder (MDD) and persistent depressive disorder (PDD), and healthy controls. The study aimed at assessing utility and accuracy of the digital technologies as potential diagnostic tools for unipolar depression, as well as correlating digital biomarkers to clinically validated psychometric questionnaires in depression. Methods: A cross-sectional, non-interventional study of 20 participants with unipolar depression (MDD and PDD/dysthymia) and 20 healthy controls was conducted at the Centre for Human Drug Research (CHDR), the Netherlands. Eligible participants attended three in-clinic visits (days 1, 7, and 14), at which they underwent a series of assessments, including conventional clinical psychometric questionnaires and digital technologies. Between the visits, there was at-home collection of data through mobile applications. In all, seven digital technologies were evaluated in this study. Three technologies were administered via mobile applications: an interactive tool for the self-assessment of mood, and a cognitive test; a passive behavioral monitor to assess social interactions and global mobility; and a platform to perform voice recordings and obtain vocal biomarkers. Four technologies were evaluated in the clinic: a neuropsychological test battery; an eye motor tracking system; a standard high-density electroencephalogram (EEG)-based technology to analyze the brain network activity during cognitive testing; and a task quantifying bias in emotion perception. Results: Our data analysis was organized by technology - to better understand individual features of various technologies. In many cases, we obtained simple, parsimonious models that have reasonably high diagnostic accuracy and potential to predict standard clinical outcome in depression. Conclusion: This study generated many useful insights for future methodology studies of digital technologies and proof-of-concept clinical trials in depression and possibly other indications.
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Affiliation(s)
| | - Jelena Curcic
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | | | - Liangke Gou
- Novartis Pharmaceuticals Corporation, East Hanover, NJ, United States
| | - Valeria De Luca
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | | | - Bingsong Zhang
- Department of Biostatistics, Bioinformatics and Biomathematics, Georgetown University, Washington, DC, United States
| | - Jens Praestgaard
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States
| | - Vanessa Vallejo
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Andrew Dolman
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States
| | | | | | - Mark Deurinck
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | | | - John J Anderson
- Neurotrack Technologies, Inc., Redwood City, CA, United States
| | - Nicholas T Bott
- Department of Medicine, School of Medicine, Stanford University, Stanford, CA, United States
| | | | | | | | | | - Raj R Jagesar
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
| | - Niels Jongs
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
| | - Martien J Kas
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
| | | | - Rob Zuiker
- Centre for Human Drug Research, Leiden, Netherlands
| | | | - Zoë Zuilhof
- Centre for Human Drug Research, Leiden, Netherlands
| | - Jang-Ho Cha
- Novartis Institutes for Biomedical Research, Cambridge, MA, United States
| | - Gabriel E Jacobs
- Centre for Human Drug Research, Leiden, Netherlands.,Department of Psychiatry, Leiden University Medical Center, Leiden, Netherlands
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2
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Hartmann S, Biliouris K, Lesko LJ, Nowak-Göttl U, Trame MN. Quantitative Systems Pharmacology Model-Based Predictions of Clinical Endpoints to Optimize Warfarin and Rivaroxaban Anti-Thrombosis Therapy. Front Pharmacol 2020; 11:1041. [PMID: 32765265 PMCID: PMC7381140 DOI: 10.3389/fphar.2020.01041] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 06/26/2020] [Indexed: 11/25/2022] Open
Abstract
Background Tight monitoring of efficacy and safety of anticoagulants such as warfarin is imperative to optimize the benefit-risk ratio of anticoagulants in patients. The standard tests used are measurements of prothrombin time (PT), usually expressed as international normalized ratio (INR), and activated partial thromboplastin time (aPTT). Objective To leverage a previously developed quantitative systems pharmacology (QSP) model of the human coagulation network to predict INR and aPTT for warfarin and rivaroxaban, respectively. Methods A modeling and simulation approach was used to predict INR and aPTT measurements of patients receiving steady-state anticoagulation therapy. A previously developed QSP model was leveraged for the present analysis. The effect of genetic polymorphisms known to influence dose response of warfarin (CYP2C9, VKORC1) were implemented into the model by modifying warfarin clearance (CYP2C9 *1: 0.2 L/h; *2: 0.14 L/h, *3: 0.04 L/h) and the concentration of available vitamin K (VKORC1 GA: −22% from normal vitamin K concentration; AA: −44% from normal vitamin K concentration). Virtual patient populations were used to assess the ability of the model to accurately predict routine INR and aPTT measurements from patients under long-term anticoagulant therapy. Results The introduced model accurately described the observed INR of patients receiving long-term warfarin treatment. The model was able to demonstrate the influence of genetic polymorphisms of CYP2C9 and VKORC1 on the INR measurements. Additionally, the model was successfully used to predict aPTT measurements for patients receiving long-term rivaroxaban therapy. Conclusion The QSP model accurately predicted INR and aPTT measurements observed during routine therapeutic drug monitoring. This is an exemplar of how a QSP model can be adapted and used as a model-based precision dosing tool during clinical practice and drug development to predict efficacy and safety of anticoagulants to ultimately help optimize anti-thrombotic therapy.
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Affiliation(s)
- Sonja Hartmann
- Center for Pharmacometrics & Systems Pharmacology, Department of Pharmaceutics, University of Florida, Orlando, FL, United States
| | - Konstantinos Biliouris
- Center for Pharmacometrics & Systems Pharmacology, Department of Pharmaceutics, University of Florida, Orlando, FL, United States
| | - Lawrence J Lesko
- Center for Pharmacometrics & Systems Pharmacology, Department of Pharmaceutics, University of Florida, Orlando, FL, United States
| | - Ulrike Nowak-Göttl
- Thrombosis & Hemostasis Treatment Center, Institute of Clinical Chemistry, University of Schleswig-Holstein, Germany
| | - Mirjam N Trame
- Center for Pharmacometrics & Systems Pharmacology, Department of Pharmaceutics, University of Florida, Orlando, FL, United States
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3
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Trame MN, Riggs M, Biliouris K, Marathe D, Mettetal J, Post TM, Rizk ML, Visser SAG, Musante CJ. Perspective on the State of Pharmacometrics and Systems Pharmacology Integration. CPT Pharmacometrics Syst Pharmacol 2018; 7:617-620. [PMID: 29761892 PMCID: PMC6202472 DOI: 10.1002/psp4.12313] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/04/2018] [Indexed: 12/31/2022]
Abstract
Reliance on modeling and simulation in drug discovery and development has dramatically increased over the past decade. Two disciplines at the forefront of this activity, pharmacometrics and systems pharmacology (SP), emerged independently from different fields; consequently, a perception exists that only few examples integrate these approaches. Herein, we review the state of pharmacometrics and SP integration and describe benefits of combining these approaches in a model-informed drug discovery and development framework.
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Affiliation(s)
- Mirjam N Trame
- Novartis Institutes for BioMedical Research, Inc, Cambridge, Massachusetts, USA
| | - Matthew Riggs
- Metrum Research Group LLC, Tariffville, Connecticut, USA
| | | | | | - Jerome Mettetal
- Drug Safety and Metabolism, IMED Biotech Unit, AstraZeneca, Boston, Massachusetts, USA
| | - Teun M Post
- Leiden Experts on Advanced Pharmacokinetics and Pharmacodynamics (LAP&P), Leiden, The Netherlands.,Division of Systems Biomedicine and Pharmacology, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | | | | | - Cynthia J Musante
- Pfizer Worldwide Research & Development, Cambridge, Massachusetts, USA
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4
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Biliouris K, Gaitonde P, Yin W, Norris DA, Wang Y, Henry S, Fey R, Nestorov I, Schmidt S, Rogge M, Lesko LJ, Trame MN. A Semi-Mechanistic Population Pharmacokinetic Model of Nusinersen: An Antisense Oligonucleotide for the Treatment of Spinal Muscular Atrophy. CPT Pharmacometrics Syst Pharmacol 2018; 7:581-592. [PMID: 30043511 PMCID: PMC6157691 DOI: 10.1002/psp4.12323] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/06/2018] [Indexed: 01/21/2023]
Abstract
A pharmacokinetic (PK) model was developed for nusinersen, an antisense oligonucleotide (ASO) that is the first approved treatment for spinal muscular atrophy (SMA). The model was built with data from 92 nonhuman primates (NHPs) following intrathecal doses (0.3–7 mg) and characterized the PK in cerebrospinal fluid (CSF), plasma, total spinal cord, brain, and pons. The estimated volumes were 13.6, 937, 4.5, 53.8, and 2.11 mL, respectively. Global sensitivity analysis demonstrated that the CSF‐to‐plasma drug distribution rate (0.09 hour−1) is a major determinant of the maximum nusinersen concentration in central nervous system (CNS) tissues. Physiological age‐based and body weight‐based allometric scaling was implemented with exponent values of −0.08 and 1 for the rate constants and the volume of distribution, respectively. Simulations of the scaled model were in agreement with clinical observations from 52 pediatric phase I PK profiles. The developed model can be used to guide the design of clinical trials with ASOs.
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Affiliation(s)
- Konstantinos Biliouris
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, College of Pharmacy, University of Florida, Orlando, Florida, USA
| | - Puneet Gaitonde
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, College of Pharmacy, University of Florida, Orlando, Florida, USA
| | - Wei Yin
- Biogen Idec, Cambridge, Massachusetts, USA
| | | | - Yanfeng Wang
- Ionis Pharmaceuticals Inc., Carlsbad, California, USA
| | - Scott Henry
- Ionis Pharmaceuticals Inc., Carlsbad, California, USA
| | - Robert Fey
- Ionis Pharmaceuticals Inc., Carlsbad, California, USA
| | | | - Stephan Schmidt
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, College of Pharmacy, University of Florida, Orlando, Florida, USA
| | - Mark Rogge
- Biogen Idec, Cambridge, Massachusetts, USA
| | - Lawrence J Lesko
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, College of Pharmacy, University of Florida, Orlando, Florida, USA
| | - Mirjam N Trame
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, College of Pharmacy, University of Florida, Orlando, Florida, USA
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5
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Hartmann S, Biliouris K, Lesko LJ, Nowak-Göttl U, Trame MN. Quantitative Systems Pharmacology Model to Predict the Effects of Commonly Used Anticoagulants on the Human Coagulation Network. CPT Pharmacometrics Syst Pharmacol 2016; 5:554-564. [PMID: 27647667 PMCID: PMC5080651 DOI: 10.1002/psp4.12111] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 08/07/2016] [Indexed: 12/14/2022] Open
Abstract
Warfarin is the anticoagulant of choice for venous thromboembolism (VTE) treatment, although its suppression of the endogenous clot-dissolution complex APC:PS may ultimately lead to longer time-to-clot dissolution profiles, resulting in increased risk of re-thrombosis. This detrimental effect might not occur during VTE treatment using other anticoagulants, such as rivaroxaban or enoxaparin, given their different mechanisms of action within the coagulation network. A quantitative systems pharmacology model was developed describing the coagulation network to monitor clotting factor levels under warfarin, enoxaparin, and rivaroxaban treatment. The model allowed for estimation of all factor rate constants and production rates. Predictions of individual coagulation factor time courses under steady-state warfarin, enoxaparin, and rivaroxaban treatment reflected the suppression of protein C and protein S under warfarin compared to rivaroxaban and enoxaparin. The model may be used as a tool during clinical practice to predict effects of anticoagulants on individual clotting factor time courses and optimize antithrombotic therapy.
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Affiliation(s)
- S Hartmann
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, Orlando, Florida, USA
| | - K Biliouris
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, Orlando, Florida, USA
| | - L J Lesko
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, Orlando, Florida, USA
| | - U Nowak-Göttl
- University of Schleswig-Holstein, Institute of Clinical Chemistry, Thrombosis and Hemostasis Treatment Center, Campus Kiel and Lübbeck, Germany
| | - M N Trame
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, Orlando, Florida, USA.
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6
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Trame MN, Biliouris K, Lesko LJ, Mettetal JT. Systems pharmacology to predict drug safety in drug development. Eur J Pharm Sci 2016; 94:93-95. [PMID: 27251780 DOI: 10.1016/j.ejps.2016.05.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [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: 01/14/2016] [Revised: 05/05/2016] [Accepted: 05/28/2016] [Indexed: 12/20/2022]
Abstract
Ensuring that drugs are safe and effective is a very high priority for drug development and the US Food and Drug Administration review process. This is especially true today because of faster approval times and smaller clinical trials, especially in oncology and rare diseases. In light of these trends, systems pharmacology is seen as an essential strategy to understand and predict adverse drug events during drug development by analyzing interactions between drugs and multiple targets rather than the traditional "one-drug-one-target" approach. This commentary offers an overview of the current trends and challenges of using systems pharmacology to reduce the risks of unintended adverse events.
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Affiliation(s)
- Mirjam N Trame
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, Lake Nona, Orlando, FL, USA.
| | - Konstantinos Biliouris
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, Lake Nona, Orlando, FL, USA
| | - Lawrence J Lesko
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida, Lake Nona, Orlando, FL, USA
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7
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Xu H, Chaudhri VK, Wu Z, Biliouris K, Dienger-Stambaugh K, Rochman Y, Singh H. Regulation of bifurcating B cell trajectories by mutual antagonism between transcription factors IRF4 and IRF8. Nat Immunol 2015; 16:1274-81. [DOI: 10.1038/ni.3287] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 08/31/2015] [Indexed: 12/17/2022]
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8
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Biliouris K, Lavielle M, Trame MN. MatVPC: A User-Friendly MATLAB-Based Tool for the Simulation and Evaluation of Systems Pharmacology Models. CPT Pharmacometrics Syst Pharmacol 2015; 4:547-57. [PMID: 26451334 PMCID: PMC4592534 DOI: 10.1002/psp4.12011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/10/2015] [Indexed: 12/13/2022]
Abstract
Quantitative systems pharmacology (QSP) models are progressively entering the arena of contemporary pharmacology. The efficient implementation and evaluation of complex QSP models necessitates the development of flexible computational tools that are built into QSP mainstream software. To this end, we present MatVPC, a versatile MATLAB-based tool that accommodates QSP models of any complexity level. MatVPC executes Monte Carlo simulations as well as automatic construction of visual predictive checks (VPCs) and quantified VPCs (QVPCs).
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Affiliation(s)
- K Biliouris
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida Orlando, Florida, USA
| | | | - M N Trame
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, University of Florida Orlando, Florida, USA
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Abstract
![]()
Titratable
systems are common tools in metabolic engineering to
tune the levels of enzymes and cellular components as part of pathway
optimization. For nonmodel microorganisms with limited genetic tools,
inducible sugar utilization pathways offer built-in titratable systems.
However, these pathways can exhibit undesirable single-cell behaviors
that hamper the uniform and tunable control of gene expression. Here,
we applied mathematical modeling and single-cell measurements of l-arabinose utilization in Escherichia coli to systematically explore how sugar utilization pathways can be
altered to achieve desirable inducible properties. We found that different
pathway alterations, such as the removal of catabolism, constitutive
expression of high-affinity or low-affinity transporters, or further
deletion of the other transporters, came with trade-offs specific
to each alteration. For instance, sugar catabolism improved the uniformity
and linearity of the response at the cost of requiring higher sugar
concentrations to induce the pathway. Within these alterations, we
also found that a uniform and linear response could be achieved with
a single alteration: constitutively expressing the high-affinity transporter.
Equivalent modifications to the d-xylose utilization pathway
yielded similar responses, demonstrating the applicability of our
observations. Overall, our findings indicate that there is no ideal
set of typical alterations when co-opting natural utilization pathways
for titratable control and suggest design rules for manipulating these
pathways to advance basic genetic studies and the metabolic engineering
of microorganisms for optimized chemical production.
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Affiliation(s)
- Taliman Afroz
- Department
of Chemical and Biomolecular Engineering North Carolina State University Raleigh, North Carolina 27695, United States
| | - Konstantinos Biliouris
- Department
of Chemical Engineering and Materials Science University of Minnesota Minneapolis, Minnesota 55455, United States
| | - Kelsey E. Boykin
- Department
of Chemical and Biomolecular Engineering North Carolina State University Raleigh, North Carolina 27695, United States
| | - Yiannis Kaznessis
- Department
of Chemical Engineering and Materials Science University of Minnesota Minneapolis, Minnesota 55455, United States
| | - Chase L. Beisel
- Department
of Chemical and Biomolecular Engineering North Carolina State University Raleigh, North Carolina 27695, United States
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10
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Afroz T, Biliouris K, Kaznessis Y, Beisel CL. Bacterial sugar utilization gives rise to distinct single-cell behaviours. Mol Microbiol 2014; 93:1093-1103. [PMID: 24976172 DOI: 10.1111/mmi.12695] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/25/2014] [Indexed: 12/15/2022]
Abstract
Inducible utilization pathways reflect widespread microbial strategies to uptake and consume sugars from the environment. Despite their broad importance and extensive characterization, little is known how these pathways naturally respond to their inducing sugar in individual cells. Here, we performed single-cell analyses to probe the behaviour of representative pathways in the model bacterium Escherichia coli. We observed diverse single-cell behaviours, including uniform responses (d-lactose, d-galactose, N-acetylglucosamine, N-acetylneuraminic acid), 'all-or-none' responses (d-xylose, l-rhamnose) and complex combinations thereof (l-arabinose, d-gluconate). Mathematical modelling and probing of genetically modified pathways revealed that the simple framework underlying these pathways - inducible transport and inducible catabolism - could give rise to most of these behaviours. Sugar catabolism was also an important feature, as disruption of catabolism eliminated tunable induction as well as enhanced memory of previous conditions. For instance, disruption of catabolism in pathways that respond to endogenously synthesized sugars led to full pathway induction even in the absence of exogenous sugar. Our findings demonstrate the remarkable flexibility of this simple biological framework, with direct implications for environmental adaptation and the engineering of synthetic utilization pathways as titratable expression systems and for metabolic engineering.
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Affiliation(s)
- Taliman Afroz
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Konstantinos Biliouris
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA
| | - Yiannis Kaznessis
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA
| | - Chase L Beisel
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
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Volzing K, Biliouris K, Smadbeck P, Kaznessis Y. Computer-Aided Design of Synthetic Biological Constructs with the Synthetic Biology Software Suite. Synth Biol (Oxf) 2013. [DOI: 10.1016/b978-0-12-394430-6.00007-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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12
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Arkin AP, Baker D, Biliouris K, Bokinsky G, Bundy BC, Carrara P, Church GM, Cirino PC, Cobb RE, Eriksen DT, Freestone T, Fussenegger M, Groff D, Guimaraes JC, Heng BC, Huang S, Itaya M, Jewett MC, Kaznessis Y, Keasling J, Kim JE, Kim TY, Kim YB, Kuruma Y, Lee SY, Li S, Liu CC, Luisi PL, Luo Y, Ma S, Mee MT, de Souza TP, Qian S, Ranji A, Richter F, Schmidt-Dannert C, Shin JH, Smadbeck P, Smith RP, Sohn SB, Stano P, Tang N, Tanouchi Y, Tian J, Tikh I, Volzing K, Wang HH, Wu JC, You L, Zhao H, Zhou JX. Contributors. Synth Biol (Oxf) 2013. [DOI: 10.1016/b978-0-12-394430-6.00022-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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13
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Biliouris K, Babson D, Schmidt-Dannert C, Kaznessis YN. Stochastic simulations of a synthetic bacteria-yeast ecosystem. BMC Syst Biol 2012; 6:58. [PMID: 22672814 PMCID: PMC3485176 DOI: 10.1186/1752-0509-6-58] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 03/08/2012] [Indexed: 01/02/2023]
Abstract
BACKGROUND The field of synthetic biology has greatly evolved and numerous functions can now be implemented by artificially engineered cells carrying the appropriate genetic information. However, in order for the cells to robustly perform complex or multiple tasks, co-operation between them may be necessary. Therefore, various synthetic biological systems whose functionality requires cell-cell communication are being designed. These systems, microbial consortia, are composed of engineered cells and exhibit a wide range of behaviors. These include yeast cells whose growth is dependent on one another, or bacteria that kill or rescue each other, synchronize, behave as predator-prey ecosystems or invade cancer cells. RESULTS In this paper, we study a synthetic ecosystem comprising of bacteria and yeast that communicate with and benefit from each other using small diffusible molecules. We explore the behavior of this heterogeneous microbial consortium, composed of Saccharomyces cerevisiae and Escherichia coli cells, using stochastic modeling. The stochastic model captures the relevant intra-cellular and inter-cellular interactions taking place in and between the eukaryotic and prokaryotic cells. Integration of well-characterized molecular regulatory elements into these two microbes allows for communication through quorum sensing. A gene controlling growth in yeast is induced by bacteria via chemical signals and vice versa. Interesting dynamics that are common in natural ecosystems, such as obligatory and facultative mutualism, extinction, commensalism and predator-prey like dynamics are observed. We investigate and report on the conditions under which the two species can successfully communicate and rescue each other. CONCLUSIONS This study explores the various behaviors exhibited by the cohabitation of engineered yeast and bacterial cells. The way that the model is built allows for studying the dynamics of any system consisting of two species communicating with one another via chemical signals. Therefore, key information acquired by our model may potentially drive the experimental design of various synthetic heterogeneous ecosystems.
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Affiliation(s)
- Konstantinos Biliouris
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave SE, Minneapolis, MN 55455, USA
| | - David Babson
- University of Minnesota Biotechnology Institute, 140 Gortner Lab, 1479 Gortner Avenue, Saint Paul, MN 55108, USA
| | - Claudia Schmidt-Dannert
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 140 Gortner Laboratory, Saint Paul, MN 55108, USA
| | - Yiannis N Kaznessis
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave SE, Minneapolis, MN 55455, USA
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14
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Volzing K, Biliouris K, Kaznessis YN. proTeOn and proTeOff, new protein devices that inducibly activate bacterial gene expression. ACS Chem Biol 2011; 6:1107-16. [PMID: 21819083 DOI: 10.1021/cb200168y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Using an original workflow, we have modeled, constructed, and characterized two new molecular devices that inducibly activate gene expression in Escherichia coli. The devices, prokaryotic-TetOn and prokaryotic-TetOff, were built by fusing an inducible DNA-binding protein domain to a transcription activation domain and constructing a complementary synthetic promoter sequence through which they could control downstream gene expression. In particular, the transactivators were built using variants of the tetracycline repressor, TetR, and the transactivating domain of the LuxR activator. The complementary promoter sequence included TetR's operator, tetO, and elements of the lux promoter. These specific protein domains and their operator sites were chosen as they have been thoroughly studied and well characterized. First, our methodology began with optimizing the geometry of the molecular components using molecular modeling. We did so to achieve an unprecedented combination of controllable and transactivating function in bacterial organisms. The devices were then built to activate the expression of green fluorescent protein. Their unique function was found to be robustly tight and activating many-fold increases of expressed gene levels, as measured by flow cytometry experiments. The devices were further characterized with stochastic kinetic models. The new devices presented herein may become useful additions to the molecular toolboxes used by biologists to control bacterial gene expression. The methodology used may also be a foundation for the design, development, and characterization of a library of such devices and more complex gene regulatory networks.
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Affiliation(s)
- Katherine Volzing
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Konstantinos Biliouris
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Yiannis N. Kaznessis
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
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15
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Abstract
Background The tetracycline operon is a self-regulated system. It is found naturally in bacteria where it confers resistance to antibiotic tetracycline. Because of the performance of the molecular elements of the tetracycline operon, these elements are widely used as parts of synthetic gene networks where the protein production can be efficiently turned on and off in response to the presence or the absence of tetracycline. In this paper, we investigate the dynamics of the tetracycline operon. To this end, we develop a mathematical model guided by experimental findings. Our model consists of biochemical reactions that capture the biomolecular interactions of this intriguing system. Having in mind that small biological systems are subjects to stochasticity, we use a stochastic algorithm to simulate the tetracycline operon behavior. A sensitivity analysis of two critical parameters embodied this system is also performed providing a useful understanding of the function of this system. Results Simulations generate a timeline of biomolecular events that confer resistance to bacteria against tetracycline. We monitor the amounts of intracellular TetR2 and TetA proteins, the two important regulatory and resistance molecules, as a function of intrecellular tetracycline. We find that lack of one of the promoters of the tetracycline operon has no influence on the total behavior of this system inferring that this promoter is not essential for Escherichia coli. Sensitivity analysis with respect to the binding strength of tetracycline to repressor and of repressor to operators suggests that these two parameters play a predominant role in the behavior of the system. The results of the simulations agree well with experimental observations such as tight repression, fast gene expression, induction with tetracycline, and small intracellular TetR2 amounts. Conclusions Computer simulations of the tetracycline operon afford augmented insight into the interplay between its molecular components. They provide useful explanations of how the components and their interactions have evolved to best serve bacteria carrying this operon. Therefore, simulations may assist in designing novel gene network architectures consisting of tetracycline operon components.
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Affiliation(s)
- Konstantinos Biliouris
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave SE, Minneapolis, MN 55455, USA
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