1
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Fillion AJ, Bricco AR, Lee HD, Korenchan D, Farrar CT, Gilad AA. Development of a synthetic biosensor for chemical exchange MRI utilizing in silico optimized peptides. NMR IN BIOMEDICINE 2023; 36:e5007. [PMID: 37469121 PMCID: PMC11075521 DOI: 10.1002/nbm.5007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/26/2023] [Accepted: 06/28/2023] [Indexed: 07/21/2023]
Abstract
Chemical exchange saturation transfer (CEST) MRI has been identified as a novel alternative to classical diagnostic imaging. Over the last several decades, many studies have been conducted to determine possible CEST agents, such as endogenously expressed compounds or proteins, that can be utilized to produce contrast with minimally invasive procedures and reduced or non-existent levels of toxicity. In recent years there has been an increased interest in the generation of genetically engineered CEST contrast agents, typically based on existing proteins with CEST contrast or modified to produce CEST contrast. We have developed an in silico method for the evolution of peptide sequences to optimize CEST contrast and showed that these peptides could be combined to create de novo biosensors for CEST MRI. A single protein, superCESTide, was designed to be 198 amino acids. SuperCESTide was expressed in E. coli and purified with size exclusion chromatography. The magnetic transfer ratio asymmetry generated by superCESTide was comparable to levels seen in previous CEST reporters, such as protamine sulfate (salmon protamine) and human protamine. These data show that novel peptides with sequences optimized in silico for CEST contrast that utilize a more comprehensive range of amino acids can still produce contrast when assembled into protein units expressed in complex living environments.
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Affiliation(s)
- Adam J. Fillion
- Department of Chemical Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Alexander R. Bricco
- Department of Biomedical Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Harvey D. Lee
- Department of Biomedical Engineering, Michigan State University, East Lansing, Michigan, USA
| | - David Korenchan
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, MA, USA
| | - Christian T. Farrar
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, MA, USA
| | - Assaf A. Gilad
- Department of Chemical Engineering, Michigan State University, East Lansing, Michigan, USA
- Department of Radiology, Michigan State University, East Lansing, Michigan, USA
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2
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Longo DL, Carella A, Corrado A, Pirotta E, Mohanta Z, Singh A, Stabinska J, Liu G, McMahon MT. A snapshot of the vast array of diamagnetic CEST MRI contrast agents. NMR IN BIOMEDICINE 2023; 36:e4715. [PMID: 35187749 PMCID: PMC9724179 DOI: 10.1002/nbm.4715] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 05/11/2023]
Abstract
Since the inception of CEST MRI in the 1990s, a number of compounds have been identified as suitable for generating contrast, including paramagnetic lanthanide complexes, hyperpolarized atom cages and, most interesting, diamagnetic compounds. In the past two decades, there has been a major emphasis in this field on the identification and application of diamagnetic compounds that have suitable biosafety profiles for usage in medical applications. Even in the past five years there has been a tremendous growth in their numbers, with more and more emphasis being placed on finding those that can be ultimately used for patient studies on clinical 3 T scanners. At this point, a number of endogenous compounds present in tissue have been identified, and also natural and synthetic organic compounds that can be administered to highlight pathology via CEST imaging. Here we will provide a very extensive snapshot of the types of diamagnetic compound that can generate CEST MRI contrast, together with guidance on their utility on typical preclinical and clinical scanners and a review of the applications that might benefit the most from this new technology.
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Affiliation(s)
- Dario Livio Longo
- Institute of Biostructures and Bioimaging (IBB), National Research Council of Italy (CNR), Turin, Italy
| | - Antonella Carella
- Institute of Biostructures and Bioimaging (IBB), National Research Council of Italy (CNR), Turin, Italy
| | - Alessia Corrado
- Institute of Biostructures and Bioimaging (IBB), National Research Council of Italy (CNR), Turin, Italy
| | - Elisa Pirotta
- Institute of Biostructures and Bioimaging (IBB), National Research Council of Italy (CNR), Turin, Italy
| | - Zinia Mohanta
- F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Aruna Singh
- F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Julia Stabinska
- F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Guanshu Liu
- F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Michael T. McMahon
- F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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3
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Gilad AA, Bar-Shir A, Bricco AR, Mohanta Z, McMahon MT. Protein and peptide engineering for chemical exchange saturation transfer imaging in the age of synthetic biology. NMR IN BIOMEDICINE 2023; 36:e4712. [PMID: 35150021 PMCID: PMC10642350 DOI: 10.1002/nbm.4712] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/02/2022] [Accepted: 02/05/2022] [Indexed: 05/23/2023]
Abstract
At the beginning of the millennium, the first chemical exchange saturation transfer (CEST) contrast agents were bio-organic molecules. However, later, metal-based CEST agents (paraCEST agents) took center stage. This did not last too long as paraCEST agents showed limited translational potential. By contrast, the CEST field gradually became dominated by metal-free CEST agents. One branch of research stemming from the original work by van Zijl and colleagues is the development of CEST agents based on polypeptides. Indeed, in the last 2 decades, tremendous progress has been achieved in this field. This includes the design of novel peptides as biosensors, genetically encoded recombinant as well as synthetic reporters. This was a result of extensive characterization and elucidation of the theoretical requirements for rational designing and engineering of such agents. Here, we provide an extensive overview of the evolution of more precise protein-based CEST agents, review the rationalization of enzyme-substrate pairs as CEST contrast enhancers, discuss the theoretical considerations to improve peptide selectivity, specificity and enhance CEST contrast. Moreover, we discuss the strong influence of synthetic biology on the development of the next generation of protein-based CEST contrast agents.
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Affiliation(s)
- Assaf A. Gilad
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan, USA
- Department of Radiology, Michigan State University, East Lansing, Michigan, USA
| | - Amnon Bar-Shir
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
| | - Alexander R. Bricco
- Department of Biomedical Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Zinia Mohanta
- Division of MR Research, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Michael T. McMahon
- Division of MR Research, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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4
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Bricco A, Miralavy I, Bo S, Perlman O, Korenchan DE, Farrar CT, McMahon MT, Banzhaf W, Gilad AA. A Genetic Programming Approach to Engineering MRI Reporter Genes. ACS Synth Biol 2023; 12:1154-1163. [PMID: 36947694 PMCID: PMC10128068 DOI: 10.1021/acssynbio.2c00648] [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] [Received: 12/01/2022] [Indexed: 03/24/2023]
Abstract
Here we develop a mechanism of protein optimization using a computational approach known as "genetic programming". We developed an algorithm called Protein Optimization Engineering Tool (POET). Starting from a small library of literature values, the use of this tool allowed us to develop proteins that produce four times more MRI contrast than what was previously state-of-the-art. Interestingly, many of the peptides produced using POET were dramatically different with respect to their sequence and chemical environment than existing CEST producing peptides, and challenge prior understandings of how those peptides function. While existing algorithms for protein engineering rely on divergent evolution, POET relies on convergent evolution and consequently allows discovery of peptides with completely different sequences that perform the same function with as good or even better efficiency. Thus, this novel approach can be expanded beyond developing imaging agents and can be used widely in protein engineering.
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Affiliation(s)
- Alexander
R. Bricco
- Department
of Biomedical Engineering, Michigan State
University, East Lansing, Michigan 48823, United States
| | - Iliya Miralavy
- Department
of Computer Science & Engineering, Michigan
State University, East Lansing, Michigan 48823, United States
| | - Shaowei Bo
- The
Russell H. Morgan Department of Radiology and Radiological Sciences,
Division of MR Research, Johns Hopkins University
School of Medicine, Baltimore, Maryland 21218, United States
| | - Or Perlman
- Department
of Biomedical Engineering, Tel Aviv University, Tel Aviv 6997801, Israel
- Sagol
School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
- Athinoula
A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical
School, Boston, Massachusetts 02138, United States
| | - David E. Korenchan
- Athinoula
A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical
School, Boston, Massachusetts 02138, United States
| | - Christian T. Farrar
- Athinoula
A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical
School, Boston, Massachusetts 02138, United States
| | - Michael T. McMahon
- The
Russell H. Morgan Department of Radiology and Radiological Sciences,
Division of MR Research, Johns Hopkins University
School of Medicine, Baltimore, Maryland 21218, United States
| | - Wolfgang Banzhaf
- Department
of Computer Science & Engineering, Michigan
State University, East Lansing, Michigan 48823, United States
| | - Assaf A. Gilad
- Department
of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48823, United States
- Department
of Radiology, Michigan State University, East Lansing, Michigan 48823, United States
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5
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Fillion AJ, Bricco AR, Lee HD, Korenchan D, Farrar CT, Gilad AA. Development of a Synthetic Biosensor for Chemical Exchange MRI Utilizing In Silico Optimized Peptides. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.08.531737. [PMID: 37016672 PMCID: PMC10071792 DOI: 10.1101/2023.03.08.531737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Chemical Exchange Saturation Transfer (CEST) magnetic resonance imaging (MRI) has been identified as a novel alternative to classical diagnostic imaging. Over the last several decades, many studies have been conducted to determine possible CEST agents, such as endogenously expressed compounds or proteins, that can be utilized to produce contrast with minimally invasive procedures and reduced or non-existent levels of toxicity. In recent years there has been an increased interest in the generation of genetically engineered CEST contrast agents, typically based on existing proteins with CEST contrast or modified to produce CEST contrast. We have developed an in-silico method for the evolution of peptide sequences to optimize CEST contrast and showed that these peptides could be combined to create de novo biosensors for CEST MRI. A single protein, superCESTide 2.0, was designed to be 198 amino acids. SuperCESTide 2.0 was expressed in E. coli and purified with size-exclusion chromatography. The magnetic transfer ratio asymmetry (MTR asym ) generated by superCESTide 2.0 was comparable to levels seen in previous CEST reporters, such as protamine sulfate (salmon protamine, SP), Poly-L-Lysine (PLL), and human protamine (hPRM1). This data shows that novel peptides with sequences optimized in silico for CEST contrast that utilizes a more comprehensive range of amino acids can still produce contrast when assembled into protein units expressed in complex living environments.
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Affiliation(s)
- Adam J. Fillion
- Department of Chemical Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Alexander R. Bricco
- Department of Biomedical Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Harvey D. Lee
- Department of Biomedical Engineering, Michigan State University, East Lansing, Michigan, USA
| | - David Korenchan
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, MA, USA
| | - Christian T. Farrar
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, MA, USA
| | - Assaf A. Gilad
- Department of Chemical Engineering, Michigan State University, East Lansing, Michigan, USA
- Department of Radiology, Michigan State University, East Lansing, Michigan, USA
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6
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Bulte JWM, Wang C, Shakeri-Zadeh A. In Vivo Cellular Magnetic Imaging: Labeled vs. Unlabeled Cells. ADVANCED FUNCTIONAL MATERIALS 2022; 32:2207626. [PMID: 36589903 PMCID: PMC9798832 DOI: 10.1002/adfm.202207626] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Indexed: 06/17/2023]
Abstract
Superparamagnetic iron oxide (SPIO)-labeling of cells has been applied for magnetic resonance imaging (MRI) cell tracking for over 30 years, having resulted in a dozen or so clinical trials. SPIO nanoparticles are biodegradable and can be broken down into elemental iron, and hence the tolerance of cells to magnetic labeling has been overall high. Over the years, however, single reports have accumulated demonstrating that the proliferation, migration, adhesion and differentiation of magnetically labeled cells may differ from unlabeled cells, with inhibition of chondrocytic differentiation of labeled human mesenchymal stem cells (hMSCs) as a notable example. This historical perspective provides an overview of some of the drawbacks that can be encountered with magnetic labeling. Now that magnetic particle imaging (MPI) cell tracking is emerging as a new in vivo cellular imaging modality, there has been a renaissance in the formulation of SPIO nanoparticles this time optimized for MPI. Lessons learned from the occasional past pitfalls encountered with SPIO-labeling of cells for MRI may expedite possible future clinical translation of (combined) MRI/MPI cell tracking.
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Affiliation(s)
- Jeff W M Bulte
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Chemical & Biomolecular Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Chao Wang
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ali Shakeri-Zadeh
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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7
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Miralavy I, Bricco AR, Gilad AA, Banzhaf W. Using genetic programming to predict and optimize protein function. PEERJ PHYSICAL CHEMISTRY 2022. [DOI: 10.7717/peerj-pchem.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Protein engineers conventionally use tools such as Directed Evolution to find new proteins with better functionalities and traits. More recently, computational techniques and especially machine learning approaches have been recruited to assist Directed Evolution, showing promising results. In this article, we propose POET, a computational Genetic Programming tool based on evolutionary computation methods to enhance screening and mutagenesis in Directed Evolution and help protein engineers to find proteins that have better functionality. As a proof-of-concept, we use peptides that generate MRI contrast detected by the Chemical Exchange Saturation Transfer contrast mechanism. The evolutionary methods used in POET are described, and the performance of POET in different epochs of our experiments with Chemical Exchange Saturation Transfer contrast are studied. Our results indicate that a computational modeling tool like POET can help to find peptides with 400% better functionality than used before.
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Affiliation(s)
- Iliya Miralavy
- BEACON Center of Evolution in Action, Michigan State University, East Lansing, MI, United States of America
- Department of Computer Science and Engineering, Michigan State University, East Lansing, MI, United States of America
| | - Alexander R. Bricco
- BEACON Center of Evolution in Action, Michigan State University, East Lansing, MI, United States of America
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI, United States of America
| | - Assaf A. Gilad
- BEACON Center of Evolution in Action, Michigan State University, East Lansing, MI, United States of America
- Department of Chemical Engineering, Michigan State University, East Lansing, MI, United States of America
| | - Wolfgang Banzhaf
- BEACON Center of Evolution in Action, Michigan State University, East Lansing, MI, United States of America
- Department of Computer Science and Engineering, Michigan State University, East Lansing, MI, United States of America
- Department of Computer Science, Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador, Canada
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8
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Yun J, Baldini M, Chowdhury R, Mukherjee A. Designing Protein-Based Probes for Sensing Biological Analytes with Magnetic Resonance Imaging. ANALYSIS & SENSING 2022; 2:e202200019. [PMID: 37409177 PMCID: PMC10321474 DOI: 10.1002/anse.202200019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
Genetically encoded sensors provide unique advantages for monitoring biological analytes with molecular and cellular-level specificity. While sensors derived from fluorescent proteins represent staple tools in biological imaging, these probes are limited to optically accessible preparations owing to physical curbs on light penetration. In contrast to optical methods, magnetic resonance imaging (MRI) may be used to noninvasively look inside intact organisms at any arbitrary depth and over large fields of view. These capabilities have spurred the development of innovative methods to connect MRI readouts with biological targets using protein-based probes that are in principle genetically encodable. Here, we highlight the state-of-the-art in MRI-based biomolecular sensors, focusing on their physical mechanisms, quantitative characteristics, and biological applications. We also describe how innovations in reporter gene technology are creating new opportunities to engineer MRI sensors that are sensitive to dilute biological targets.
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Affiliation(s)
- Jason Yun
- Department of Chemistry, University of California, Santa Barbara, CA 93106, USA
| | - Michelle Baldini
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, USA
| | - Rochishnu Chowdhury
- Mechanical Engineering, University of California, Santa Barbara, CA 93106, USA
| | - Arnab Mukherjee
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, USA
- Department of Chemistry, University of California, Santa Barbara, CA 93106, USA
- Biomolecular Science and Engineering, University of California, Santa Barbara, CA 93106, USA
- Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA
- Center for BioEngineering, University of California, Santa Barbara, CA 93106, USA
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9
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Kombala CJ, Lokugama SD, Kotrotsou A, Li T, Pollard AC, Pagel MD. Simultaneous Evaluations of pH and Enzyme Activity with a CEST MRI Contrast Agent. ACS Sens 2021; 6:4535-4544. [PMID: 34856102 DOI: 10.1021/acssensors.1c02408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The extracellular tumor microenvironment of many solid tumors has high acidosis and high protease activity. Simultaneously assessing both characteristics may improve diagnostic evaluations of aggressive tumors and the effects of anticancer treatments. Noninvasive imaging methods have previously been developed that measure extracellular pH or can detect enzyme activity using chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI). Herein, we developed a single-hybrid CEST agent that can simultaneously measure pH and evaluate protease activity using a combination of dual-power acidoCEST MRI and catalyCEST MRI. Our agent showed CEST signals at 9.2 ppm from a salicylic acid moiety and at 5.0 ppm from an aryl amide. The CEST signal at 9.2 ppm could be measured after selective saturation was applied at 1 and 4 μT, and these measurements could be used with a ratiometric analysis to determine pH. The CEST signal at 5.0 ppm from the aryl amide disappeared after the agent was treated with cathepsin B, while the CEST signal at 9.2 ppm remained, indicating that the agent could detect protease activity through the amide bond cleavage. Michaelis-Menten kinetics studies with catalyCEST MRI demonstrated that the binding affinity (as shown with the Michaelis constant KM), the catalytic turnover rate (kcat), and catalytic efficiency (kcat/KM) were each higher for cathepsin B at lower pH. The kcat rates measured with catalyCEST MRI were lower than the comparable rates measured with liquid chromatography-mass spectrometry (LC-MS), which reflected a limitation of inherently noisy and relatively insensitive CEST MRI analyses. Although this level of precision limited catalyCEST MRI to semiquantitative evaluations, these semiquantitative assessments of high and low protease activity still had value by demonstrating that high acidosis and high protease activity can be used as synergistic, multiparametric biomarkers.
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Affiliation(s)
- Chathuri J. Kombala
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
| | - Sanjaya D. Lokugama
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
| | - Aikaterini Kotrotsou
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
| | - Tianzhe Li
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
| | - Alyssa C. Pollard
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
- Department of Chemistry, Rice University, Houston, Texas 77251, United States
| | - Mark D. Pagel
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, Texas 77054, United States
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10
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Liu G, van Zijl PC. CEST (Chemical Exchange Saturation Transfer) MR Molecular Imaging. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00012-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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11
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Perlman O, Ito H, Gilad AA, McMahon MT, Chiocca EA, Nakashima H, Farrar CT. Redesigned reporter gene for improved proton exchange-based molecular MRI contrast. Sci Rep 2020; 10:20664. [PMID: 33244130 PMCID: PMC7692519 DOI: 10.1038/s41598-020-77576-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 11/05/2020] [Indexed: 02/07/2023] Open
Abstract
Reporter gene imaging allows for non-invasive monitoring of molecular processes in living cells, providing insights on the mechanisms underlying pathology and therapy. A lysine-rich protein (LRP) chemical exchange saturation transfer (CEST) MRI reporter gene has previously been developed and used to image tumor cells, cardiac viral gene transfer, and oncolytic virotherapy. However, the highly repetitive nature of the LRP reporter gene sequence leads to DNA recombination events and the expression of a range of truncated LRP protein fragments, thereby greatly limiting the CEST sensitivity. Here we report the use of a redesigned LRP reporter (rdLRP), aimed to provide excellent stability and CEST sensitivity. The rdLRP contains no DNA repeats or GC rich regions and 30% less positively charged amino-acids. RT-PCR of cell lysates transfected with rdLRP demonstrated a stable reporter gene with a single distinct band corresponding to full-length DNA. A distinct increase in CEST-MRI contrast was obtained in cell lysates of rdLRP transfected cells and in in vivo LRP expressing mouse brain tumors ([Formula: see text], n = 10).
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Affiliation(s)
- Or Perlman
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, 149 13th Street, Suite 2301, Charlestown, MA, 02129, USA
| | - Hirotaka Ito
- Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Assaf A Gilad
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI, USA
- The Institute of Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, USA
- Department of Radiology, Michigan State University, East Lansing, MI, USA
| | - Michael T McMahon
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- Division of MR Research, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - E Antonio Chiocca
- Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Hiroshi Nakashima
- Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Christian T Farrar
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, 149 13th Street, Suite 2301, Charlestown, MA, 02129, USA.
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12
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Cai X, Zhang J, Lu J, Yi L, Han Z, Zhang S, Yang X, Liu G. N-Aryl Amides as Chemical Exchange Saturation Transfer Magnetic Resonance Imaging Contrast Agents. Chemistry 2020; 26:11705-11709. [PMID: 32639618 PMCID: PMC10186200 DOI: 10.1002/chem.202002415] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/28/2020] [Indexed: 12/22/2022]
Abstract
Chemical exchange saturation transfer (CEST) MRI has recently emerged as a versatile molecular imaging approach in which diamagnetic compounds can be utilized to generate an MRI signal. To expand the scope of CEST MRI applications, herein, we systematically investigated the CEST properties of N-aryl amides with different N-aromatic substitution, revealing their chemical shifts (4.6-5.8 ppm) and exchange rates (up to thousands s-1 ) are favorable to be used as CEST agents as compared to alkyl amides. As the first proof-of-concept study, we used CEST MRI to detect the enzymatic metabolism of the drug acebutolol directly by its intrinsic CEST signal without any chemical labeling. Our study implies that N-aryl amides may enable the label-free CEST MRI detection of the metabolism of many N-aryl amide-containing drugs and a variety of enzymes that act on N-aryl amides, greatly expanding the scope of CEST MR molecular imaging.
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Affiliation(s)
- Xuekang Cai
- Department of Nuclear Medicine, Peking University First Hospital, 100034, Beijing, P. R. China.,State Key Laboratory of Organic-Inorganic Composites and Beijing Key Lab of Bioprocess, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, 100029, Beijing, P. R. China.,Institute of Medical Technology, Peking University, 100871, Beijing, P. R. China
| | - Jia Zhang
- Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, 21205, USA
| | - Jiaqi Lu
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, 21218, USA
| | - Long Yi
- State Key Laboratory of Organic-Inorganic Composites and Beijing Key Lab of Bioprocess, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, 100029, Beijing, P. R. China.,Institute of Medical Technology, Peking University, 100871, Beijing, P. R. China
| | - Zheng Han
- Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, 21205, USA
| | - Shuixing Zhang
- Department of Radiology, The First Affiliated Hospital of Jinan University, 510632, Guangzhou, Guandong, P. R. China
| | - Xing Yang
- Department of Nuclear Medicine, Peking University First Hospital, 100034, Beijing, P. R. China.,Institute of Medical Technology, Peking University, 100871, Beijing, P. R. China
| | - Guanshu Liu
- Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, 21205, USA
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13
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Zhang J, Yuan Y, Gao M, Han Z, Chu C, Li Y, van Zijl PCM, Ying M, Bulte JWM, Liu G. Carbon Dots as a New Class of Diamagnetic Chemical Exchange Saturation Transfer (diaCEST) MRI Contrast Agents. Angew Chem Int Ed Engl 2019; 58:9871-9875. [PMID: 31162873 PMCID: PMC6897491 DOI: 10.1002/anie.201904722] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Indexed: 12/22/2022]
Abstract
While carbon dots (C-dots) have been extensively investigated pertaining to their fluorescent, phosphorescent, electrochemiluminescent, optoelectronic, and catalytic features, their inherent chemical exchange saturation transfer magnetic resonance imaging (CEST MRI) properties are unknown. By virtue of their hydrophilicity and abundant exchangeable protons of hydroxyl, amine, and amide anchored on the surface, we report here that C-dots can be adapted as effective diamagnetic CEST (diaCEST) MRI contrast agents. As a proof-of-concept demonstration, human glioma cells were labeled with liposomes with or without encapsulated C-dots and implanted in mouse brain. In vivo CEST MRI was able to clearly differentiate labeled cells from non-labeled cells. The present findings may encourage new applications of C-dots for in vivo imaging in deep tissues, which is currently not possible using conventional fluorescent (near-infrared) C-dots.
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Affiliation(s)
- Jia Zhang
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
| | - Yue Yuan
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
| | - Minling Gao
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
| | - Zheng Han
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
| | - Chengyan Chu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
| | - Yuguo Li
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
| | - Peter C. M. van Zijl
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
- F.M Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD (USA)
| | - Mingyao Ying
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
| | - Jeff W. M. Bulte
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
- F.M Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD (USA)
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
| | - Guanshu Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD (USA)
- F.M Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD (USA)
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14
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Zhang J, Yuan Y, Gao M, Han Z, Chu C, Li Y, van Zijl PCM, Ying M, Bulte JWM, Liu G. Carbon Dots as a New Class of Diamagnetic Chemical Exchange Saturation Transfer (diaCEST) MRI Contrast Agents. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201904722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jia Zhang
- The Russell H. Morgan Department of Radiology and Radiological ScienceDivision of MR ResearchThe Johns Hopkins University School of Medicine Baltimore MD USA
| | - Yue Yuan
- The Russell H. Morgan Department of Radiology and Radiological ScienceDivision of MR ResearchThe Johns Hopkins University School of Medicine Baltimore MD USA
- Cellular Imaging Section and Vascular Biology ProgramInstitute for Cell EngineeringThe Johns Hopkins University School of Medicine Baltimore MD USA
| | - Minling Gao
- Department of NeurologyThe Johns Hopkins University School of Medicine Baltimore MD USA
| | - Zheng Han
- The Russell H. Morgan Department of Radiology and Radiological ScienceDivision of MR ResearchThe Johns Hopkins University School of Medicine Baltimore MD USA
| | - Chengyan Chu
- The Russell H. Morgan Department of Radiology and Radiological ScienceDivision of MR ResearchThe Johns Hopkins University School of Medicine Baltimore MD USA
- Cellular Imaging Section and Vascular Biology ProgramInstitute for Cell EngineeringThe Johns Hopkins University School of Medicine Baltimore MD USA
| | - Yuguo Li
- The Russell H. Morgan Department of Radiology and Radiological ScienceDivision of MR ResearchThe Johns Hopkins University School of Medicine Baltimore MD USA
| | - Peter C. M. van Zijl
- The Russell H. Morgan Department of Radiology and Radiological ScienceDivision of MR ResearchThe Johns Hopkins University School of Medicine Baltimore MD USA
- F.M Kirby Research Center for Functional Brain ImagingKennedy Krieger Institute Baltimore MD USA
| | - Mingyao Ying
- Department of NeurologyThe Johns Hopkins University School of Medicine Baltimore MD USA
| | - Jeff W. M. Bulte
- The Russell H. Morgan Department of Radiology and Radiological ScienceDivision of MR ResearchThe Johns Hopkins University School of Medicine Baltimore MD USA
- F.M Kirby Research Center for Functional Brain ImagingKennedy Krieger Institute Baltimore MD USA
- Cellular Imaging Section and Vascular Biology ProgramInstitute for Cell EngineeringThe Johns Hopkins University School of Medicine Baltimore MD USA
| | - Guanshu Liu
- The Russell H. Morgan Department of Radiology and Radiological ScienceDivision of MR ResearchThe Johns Hopkins University School of Medicine Baltimore MD USA
- F.M Kirby Research Center for Functional Brain ImagingKennedy Krieger Institute Baltimore MD USA
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15
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Han Z, Li Y, Zhang J, Liu J, Chen C, van Zijl PC, Liu G. Molecular Imaging of Deoxycytidine Kinase Activity Using Deoxycytidine-Enhanced CEST MRI. Cancer Res 2019; 79:2775-2783. [PMID: 30940660 DOI: 10.1158/0008-5472.can-18-3565] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 02/26/2019] [Accepted: 03/27/2019] [Indexed: 11/16/2022]
Abstract
Deoxycytidine kinase (DCK) is a key enzyme for the activation of a broad spectrum of nucleoside-based chemotherapy drugs (e.g., gemcitabine); low DCK activity is one of the most important causes of cancer drug-resistance. Noninvasive imaging methods that can quantify DCK activity are invaluable for assessing tumor resistance and predicting treatment efficacy. Here we developed a "natural" MRI approach to detect DCK activity using its natural substrate deoxycytidine (dC) as the imaging probe, which can be detected directly by chemical exchange saturation transfer (CEST) MRI without any synthetic labeling. CEST MRI contrast of dC and its phosphorylated form, dCTP, successfully discriminated DCK activity in two mouse leukemia cell lines with different DCK expression. This dC-enhanced CEST MRI in xenograft leukemic cancer mouse models demonstrated that DCK(+) tumors have a distinctive dynamic CEST contrast enhancement and a significantly higher CEST contrast than DCK(-) tumors (AUC0-60 min = 0.47 ± 0.25 and 0.20 ± 0.13, respectively; P = 0.026, paired Student t test, n = 4) at 1 hour after the injection of dC. dC-enhanced CEST contrast also correlated well with tumor responses to gemcitabine treatment. This study demonstrates a novel MR molecular imaging approach for predicting cancer resistance using natural, nonradioactive, nonmetallic, and clinically available agents. This method has great potential for pursuing personalized chemotherapy by stratifying patients with different DCK activity. SIGNIFICANCE: A new molecular MRI method that detects deoxycytidine kinase activity using its natural substrate deoxycytidine has great translational potential for clinical assessment of tumor resistance and prediction of treatment efficacy.
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Affiliation(s)
- Zheng Han
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Yuguo Li
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Jia Zhang
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Jing Liu
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland.,Radiology College, Guizhou Medical University, Guiyang, Guizhou, P.R. China
| | - Chuheng Chen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Peter C van Zijl
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Guanshu Liu
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland. .,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
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16
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Ntziachristos V, Pleitez MA, Aime S, Brindle KM. Emerging Technologies to Image Tissue Metabolism. Cell Metab 2019; 29:518-538. [PMID: 30269982 DOI: 10.1016/j.cmet.2018.09.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/24/2018] [Accepted: 09/02/2018] [Indexed: 12/19/2022]
Abstract
Due to the implication of altered metabolism in a large spectrum of tissue function and disease, assessment of metabolic processes becomes essential in managing health. In this regard, imaging can play a critical role in allowing observation of biochemical and physiological processes. Nuclear imaging methods, in particular positron emission tomography, have been widely employed for imaging metabolism but are mainly limited by the use of ionizing radiation and the sensing of only one parameter at each scanning session. Observations in healthy individuals or longitudinal studies of disease could markedly benefit from non-ionizing, multi-parameter imaging methods. We therefore focus this review on progress with the non-ionizing radiation methods of MRI, hyperpolarized magnetic resonance and magnetic resonance spectroscopy, chemical exchange saturation transfer, and emerging optoacoustic (photoacoustic) imaging. We also briefly discuss the role of nuclear and optical imaging methods for research and clinical protocols.
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Affiliation(s)
- Vasilis Ntziachristos
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg 85764, Germany; Chair of Biological Imaging, TranslaTUM, Technical University of Munich, Ismaningerstr. 22, Munich 81675, Germany.
| | - Miguel A Pleitez
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg 85764, Germany; Chair of Biological Imaging, TranslaTUM, Technical University of Munich, Ismaningerstr. 22, Munich 81675, Germany
| | - Silvio Aime
- Molecular Imaging Center, Department of Molecular Biotechnologies and Health Sciences, University of Turin, Turin 10126, Italy
| | - Kevin M Brindle
- Department of Biochemistry, University of Cambridge, Old Addenbrooke's Site, Cambridge CB2 1GA, UK; Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
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17
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Wahsner J, Gale EM, Rodríguez-Rodríguez A, Caravan P. Chemistry of MRI Contrast Agents: Current Challenges and New Frontiers. Chem Rev 2019; 119:957-1057. [PMID: 30350585 PMCID: PMC6516866 DOI: 10.1021/acs.chemrev.8b00363] [Citation(s) in RCA: 813] [Impact Index Per Article: 162.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Tens of millions of contrast-enhanced magnetic resonance imaging (MRI) exams are performed annually around the world. The contrast agents, which improve diagnostic accuracy, are almost exclusively small, hydrophilic gadolinium(III) based chelates. In recent years concerns have arisen surrounding the long-term safety of these compounds, and this has spurred research into alternatives. There has also been a push to develop new molecularly targeted contrast agents or agents that can sense pathological changes in the local environment. This comprehensive review describes the state of the art of clinically approved contrast agents, their mechanism of action, and factors influencing their safety. From there we describe different mechanisms of generating MR image contrast such as relaxation, chemical exchange saturation transfer, and direct detection and the types of molecules that are effective for these purposes. Next we describe efforts to make safer contrast agents either by increasing relaxivity, increasing resistance to metal ion release, or by moving to gadolinium(III)-free alternatives. Finally we survey approaches to make contrast agents more specific for pathology either by direct biochemical targeting or by the design of responsive or activatable contrast agents.
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Affiliation(s)
- Jessica Wahsner
- Athinoula A. Martinos Center for Biomedical Imaging and the Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Eric M. Gale
- Athinoula A. Martinos Center for Biomedical Imaging and the Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Aurora Rodríguez-Rodríguez
- Athinoula A. Martinos Center for Biomedical Imaging and the Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Peter Caravan
- Athinoula A. Martinos Center for Biomedical Imaging and the Institute for Innovation in Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
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18
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19
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Mukherjee A, Davis HC, Ramesh P, Lu GJ, Shapiro MG. Biomolecular MRI reporters: Evolution of new mechanisms. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2017; 102-103:32-42. [PMID: 29157492 PMCID: PMC5726449 DOI: 10.1016/j.pnmrs.2017.05.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 05/23/2017] [Accepted: 05/28/2017] [Indexed: 05/08/2023]
Abstract
Magnetic resonance imaging (MRI) is a powerful technique for observing the function of specific cells and molecules inside living organisms. However, compared to optical microscopy, in which fluorescent protein reporters are available to visualize hundreds of cellular functions ranging from gene expression and chemical signaling to biomechanics, to date relatively few such reporters are available for MRI. Efforts to develop MRI-detectable biomolecules have mainly focused on proteins transporting paramagnetic metals for T1 and T2 relaxation enhancement or containing large numbers of exchangeable protons for chemical exchange saturation transfer. While these pioneering developments established several key uses of biomolecular MRI, such as imaging of gene expression and functional biosensing, they also revealed that low molecular sensitivity poses a major challenge for broader adoption in biology and medicine. Recently, new classes of biomolecular reporters have been developed based on alternative contrast mechanisms, including enhancement of spin diffusivity, interactions with hyperpolarized nuclei, and modulation of blood flow. These novel reporters promise to improve sensitivity and enable new forms of multiplexed and functional imaging.
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Affiliation(s)
- Arnab Mukherjee
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Hunter C Davis
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Pradeep Ramesh
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - George J Lu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Mikhail G Shapiro
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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20
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Piraner DI, Farhadi A, Davis HC, Wu D, Maresca D, Szablowski JO, Shapiro MG. Going Deeper: Biomolecular Tools for Acoustic and Magnetic Imaging and Control of Cellular Function. Biochemistry 2017; 56:5202-5209. [PMID: 28782927 PMCID: PMC6058970 DOI: 10.1021/acs.biochem.7b00443] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Most cellular phenomena of interest to mammalian biology occur within the context of living tissues and organisms. However, today's most advanced tools for observing and manipulating cellular function, based on fluorescent or light-controlled proteins, work best in cultured cells, transparent model species, or small, surgically accessed anatomical regions. Their reach into deep tissues and larger animals is limited by photon scattering. To overcome this limitation, we must design biochemical tools that interface with more penetrant forms of energy. For example, sound waves and magnetic fields easily permeate most biological tissues, allowing the formation of images and delivery of energy for actuation. These capabilities are widely used in clinical techniques such as diagnostic ultrasound, magnetic resonance imaging, focused ultrasound ablation, and magnetic particle hyperthermia. Each of these modalities offers spatial and temporal precision that could be used to study a multitude of cellular processes in vivo. However, connecting these techniques to cellular functions such as gene expression, proliferation, migration, and signaling requires the development of new biochemical tools that can interact with sound waves and magnetic fields as optogenetic tools interact with photons. Here, we discuss the exciting challenges this poses for biomolecular engineering and provide examples of recent advances pointing the way to greater depth in in vivo cell biology.
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Affiliation(s)
- Dan I. Piraner
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Arash Farhadi
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Hunter C. Davis
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Di Wu
- Division of Engineering and Applied Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - David Maresca
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Jerzy O. Szablowski
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Mikhail G. Shapiro
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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21
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Jurgielewicz P, Harmsen S, Wei E, Bachmann MH, Ting R, Aras O. New imaging probes to track cell fate: reporter genes in stem cell research. Cell Mol Life Sci 2017; 74:4455-4469. [PMID: 28674728 DOI: 10.1007/s00018-017-2584-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 06/06/2017] [Accepted: 06/26/2017] [Indexed: 01/09/2023]
Abstract
Cell fate is a concept used to describe the differentiation and development of a cell in its organismal context over time. It is important in the field of regenerative medicine, where stem cell therapy holds much promise but is limited by our ability to assess its efficacy, which is mainly due to the inability to monitor what happens to the cells upon engraftment to the damaged tissue. Currently, several imaging modalities can be used to track cells in the clinical setting; however, they do not satisfy many of the criteria necessary to accurately assess several aspects of cell fate. In recent years, reporter genes have become a popular option for tracking transplanted cells, via various imaging modalities in small mammalian animal models. This review article examines the reporter gene strategies used in imaging modalities such as MRI, SPECT/PET, Optoacoustic and Bioluminescence Imaging. Strengths and limitations of the use of reporter genes in each modality are discussed.
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Affiliation(s)
- Piotr Jurgielewicz
- Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Stefan Harmsen
- Department of Pediatrics, Stanford University, Stanford, CA, 94305, USA
| | | | | | - Richard Ting
- Department of Radiology, Weill Cornell Medicine, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Omer Aras
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 300 East 66th Street, Suite 1511, New York, NY, 10065, USA.
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22
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Gilad AA, Shapiro MG. Molecular Imaging in Synthetic Biology, and Synthetic Biology in Molecular Imaging. Mol Imaging Biol 2017; 19:373-378. [PMID: 28213833 PMCID: PMC6058969 DOI: 10.1007/s11307-017-1062-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Biomedical synthetic biology is an emerging field in which cells are engineered at the genetic level to carry out novel functions with relevance to biomedical and industrial applications. This approach promises new treatments, imaging tools, and diagnostics for diseases ranging from gastrointestinal inflammatory syndromes to cancer, diabetes, and neurodegeneration. As these cellular technologies undergo pre-clinical and clinical development, it is becoming essential to monitor their location and function in vivo, necessitating appropriate molecular imaging strategies, and therefore, we have created an interest group within the World Molecular Imaging Society focusing on synthetic biology and reporter gene technologies. Here, we highlight recent advances in biomedical synthetic biology, including bacterial therapy, immunotherapy, and regenerative medicine. We then discuss emerging molecular imaging approaches to facilitate in vivo applications, focusing on reporter genes for noninvasive modalities such as magnetic resonance, ultrasound, photoacoustic imaging, bioluminescence, and radionuclear imaging. Because reporter genes can be incorporated directly into engineered genetic circuits, they are particularly well suited to imaging synthetic biological constructs, and developing them provides opportunities for creative molecular and genetic engineering.
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Affiliation(s)
- Assaf A Gilad
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
| | - Mikhail G Shapiro
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA.
- Heritage Medical Research Institute, California Institute of Technology, Pasadena, CA, USA.
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23
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McMahon MT, Gilad AA. Cellular and Molecular Imaging Using Chemical Exchange Saturation Transfer. Top Magn Reson Imaging 2017; 25:197-204. [PMID: 27748713 DOI: 10.1097/rmr.0000000000000105] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Chemical exchange saturation transfer (CEST) is a powerful new tool well suited for molecular imaging. This technology enables the detection of low concentration probes through selective labeling of rapidly exchanging protons or other spins on the probes. In this review, we will highlight the unique features of CEST imaging technology and describe the different types of CEST agents that are suited for molecular imaging studies, including CEST theranostic agents, CEST reporter genes, and CEST environmental sensors.
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Affiliation(s)
- Michael T McMahon
- *F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute †The Russell H. Morgan Department of Radiology and Radiological Sciences, Division of MR Research ‡Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD
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24
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Advances in Monitoring Cell-Based Therapies with Magnetic Resonance Imaging: Future Perspectives. Int J Mol Sci 2017; 18:ijms18010198. [PMID: 28106829 PMCID: PMC5297829 DOI: 10.3390/ijms18010198] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 01/05/2017] [Accepted: 01/10/2017] [Indexed: 01/07/2023] Open
Abstract
Cell-based therapies are currently being developed for applications in both regenerative medicine and in oncology. Preclinical, translational, and clinical research on cell-based therapies will benefit tremendously from novel imaging approaches that enable the effective monitoring of the delivery, survival, migration, biodistribution, and integration of transplanted cells. Magnetic resonance imaging (MRI) offers several advantages over other imaging modalities for elucidating the fate of transplanted cells both preclinically and clinically. These advantages include the ability to image transplanted cells longitudinally at high spatial resolution without exposure to ionizing radiation, and the possibility to co-register anatomical structures with molecular processes and functional changes. However, since cellular MRI is still in its infancy, it currently faces a number of challenges, which provide avenues for future research and development. In this review, we describe the basic principle of cell-tracking with MRI; explain the different approaches currently used to monitor cell-based therapies; describe currently available MRI contrast generation mechanisms and strategies for monitoring transplanted cells; discuss some of the challenges in tracking transplanted cells; and suggest future research directions.
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25
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Non-invasive imaging using reporter genes altering cellular water permeability. Nat Commun 2016; 7:13891. [PMID: 28008959 PMCID: PMC5196229 DOI: 10.1038/ncomms13891] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 11/10/2016] [Indexed: 12/19/2022] Open
Abstract
Non-invasive imaging of gene expression in live, optically opaque animals is important for multiple applications, including monitoring of genetic circuits and tracking of cell-based therapeutics. Magnetic resonance imaging (MRI) could enable such monitoring with high spatiotemporal resolution. However, existing MRI reporter genes based on metalloproteins or chemical exchange probes are limited by their reliance on metals or relatively low sensitivity. Here we introduce a new class of MRI reporters based on the human water channel aquaporin 1. We show that aquaporin overexpression produces contrast in diffusion-weighted MRI by increasing tissue water diffusivity without affecting viability. Low aquaporin levels or mixed populations comprising as few as 10% aquaporin-expressing cells are sufficient to produce MRI contrast. We characterize this new contrast mechanism through experiments and simulations, and demonstrate its utility in vivo by imaging gene expression in tumours. Our results establish an alternative class of sensitive, metal-free reporter genes for non-invasive imaging. Magnetic resonance imaging combined with molecular reporters can visualise cellular functions in intact organisms. Here Mukherjee et al. present a cellular imaging approach based on intracellular changes in water diffusion using human aquaporin 1 gene as a genetically encoded reporter for MRI.
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26
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Sinharay S, Pagel MD. Advances in Magnetic Resonance Imaging Contrast Agents for Biomarker Detection. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2016; 9:95-115. [PMID: 27049630 PMCID: PMC4911245 DOI: 10.1146/annurev-anchem-071015-041514] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Recent advances in magnetic resonance imaging (MRI) contrast agents have provided new capabilities for biomarker detection through molecular imaging. MRI contrast agents based on the T2 exchange mechanism have more recently expanded the armamentarium of agents for molecular imaging. Compared with T1 and T2* agents, T2 exchange agents have a slower chemical exchange rate, which improves the ability to design these MRI contrast agents with greater specificity for detecting the intended biomarker. MRI contrast agents that are detected through chemical exchange saturation transfer (CEST) have even slower chemical exchange rates. Another emerging class of MRI contrast agents uses hyperpolarized (13)C to detect the agent with outstanding sensitivity. These hyperpolarized (13)C agents can be used to track metabolism and monitor characteristics of the tissue microenvironment. Together, these various MRI contrast agents provide excellent opportunities to develop molecular imaging for biomarker detection.
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Affiliation(s)
- Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85724;
| | - Mark D Pagel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85724;
- Department of Medical Imaging, University of Arizona, Tucson, Arizona 85724;
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27
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Sinharay S, Randtke EA, Jones KM, Howison CM, Chambers SK, Kobayashi H, Pagel MD. Noninvasive detection of enzyme activity in tumor models of human ovarian cancer using catalyCEST MRI. Magn Reson Med 2016; 77:2005-2014. [PMID: 27221386 DOI: 10.1002/mrm.26278] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/25/2016] [Accepted: 04/25/2016] [Indexed: 12/17/2022]
Abstract
PURPOSE We proposed to detect the in vivo enzyme activity of γ-glutamyl transferase (GGT) within mouse models of human ovarian cancers using catalyCEST MRI with a diamagnetic CEST agent. METHODS A CEST-FISP MRI protocol and a diamagnetic CEST agent were developed to detect GGT enzyme activity in biochemical solution. A quantitative Michaelis-Menten enzyme kinetics study was performed to confirm that catalyCEST MRI can measure enzyme activity. In vivo catalyCEST MRI studies generated pixel-wise activity maps of GGT activities. Ex vivo fluorescence imaging was performed for validation. RESULTS CatalyCEST MRI selectively detected two CEST signals from a single CEST agent, whereby one CEST signal was responsive to GGT enzyme activity and the other CEST signal was an unresponsive control signal. The comparison of these CEST signals facilitated in vivo catalyCEST MRI studies that detected high GGT activity in OVCAR-8 tumors, low GGT activity in OVCAR-3 tumors, and low or no GGT activity in muscle tissues. CONCLUSION CatalyCEST MRI with a diamagnetic CEST agent can detect the level of GGT enzyme activity within in vivo tumor models of human ovarian cancers. Magn Reson Med 77:2005-2014, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Edward A Randtke
- Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA
| | - Kyle M Jones
- Biomedical Engineering Graduate Interdisciplinary Program, University of Arizona, Tucson, Arizona, USA
| | | | - Setsuko K Chambers
- Department of Obstetrics and Gynecology, University of Arizona, Tucson, Arizona, USA.,University of Arizona Cancer Center, University of Arizona, Tucson, Arizona, USA
| | - Hisataka Kobayashi
- Laboratory of Molecular Theranostics, National Cancer Institute, NIH, Bethesda, Maryland, USA
| | - Mark D Pagel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA.,Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA.,University of Arizona Cancer Center, University of Arizona, Tucson, Arizona, USA
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28
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Fernández-Cuervo G, Sinharay S, Pagel MD. A CatalyCEST MRI Contrast Agent that Can Simultaneously Detect Two Enzyme Activities. Chembiochem 2016; 17:383-7. [PMID: 26693680 PMCID: PMC4814164 DOI: 10.1002/cbic.201500586] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Indexed: 12/28/2022]
Abstract
The simultaneous detection of multiple enzyme activities can improve the specificity of disease diagnoses. We therefore synthesized and characterized a diamagnetic chemical exchange saturation transfer (CEST) MRI contrast agent that can simultaneously detect two enzyme activities. Sulfatase and esterase enzymes cleave the ligands of the CEST agent, releasing salicylic acid that can be detected with CEST MRI. Importantly, both enzymes are required to activate the agent to produce a CEST MRI contrast, and the CEST agent was stable without enzyme treatment. These results established that this diamagnetic CEST MRI contrast agent is a platform technology with a modular design that can be potentially exploited to detect other combinations of enzyme activities, which can expand the armamentarium of contrast agents for molecular imaging.
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Affiliation(s)
- Gabriela Fernández-Cuervo
- Department of Pharmaceutical Sciences, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724, USA
| | - Sanhita Sinharay
- Department of Chemistry and Biochemistry, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724, USA
| | - Mark D Pagel
- Department of Medical Imaging, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724, USA.
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29
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Hingorani DV, Montano LA, Randtke EA, Lee YS, Cárdenas-Rodríguez J, Pagel MD. A single diamagnetic catalyCEST MRI contrast agent that detects cathepsin B enzyme activity by using a ratio of two CEST signals. CONTRAST MEDIA & MOLECULAR IMAGING 2016; 11:130-8. [PMID: 26633584 PMCID: PMC4882611 DOI: 10.1002/cmmi.1672] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 09/06/2015] [Accepted: 10/02/2015] [Indexed: 12/31/2022]
Abstract
CatalyCEST MRI can detect enzyme activity by monitoring the change in chemical exchange with water after a contrast agent is cleaved by an enzyme. Often these molecules use paramagnetic metals and are delivered with an additional non-responsive reference molecule. To improve this approach for molecular imaging, a single diamagnetic agent with enzyme-responsive and enzyme-unresponsive CEST signals was synthesized and characterized. The CEST signal from the aryl amide disappeared after cleavage of a dipeptidyl ligand with cathepsin B, while a salicylic acid moiety was largely unresponsive to enzyme activity. The ratiometric comparison of the two CEST signals from the same agent allowed for concentration independent measurements of enzyme activity. The chemical exchange rate of the salicylic acid moiety was unchanged after enzyme catalysis, which further validated that this moiety was enzyme-unresponsive. The temperature dependence of the chemical exchange rate of the salicylic acid moiety was non-Arrhenius, suggesting a two-step chemical exchange mechanism for salicylic acid. The good detection sensitivity at low saturation power facilitates clinical translation, along with the potentially low toxicity of a non-metallic MRI contrast agent. The modular design of the agent constitutes a platform technology that expands the variety of agents that may be employed by catalyCEST MRI for molecular imaging.
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Affiliation(s)
- Dina V. Hingorani
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
- Department of Surgery, University of California, San Diego, 9500 Gilman Dr, George Palade 310, La Jolla, CA 92093-0647, USA
| | - Luis A. Montano
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | - Edward A. Randtke
- Department of Medical Imaging, University of Arizona, Tucson, AZ, USA
| | - Yeon Sun Lee
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | | | - Mark D. Pagel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
- Department of Medical Imaging, University of Arizona, Tucson, AZ, USA
- University of Arizona Cancer Center, 1515 N Campbell Ave., Tucson, AZ, 85724-5024, USA
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30
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Zheng Z, Sun H, Hu C, Li G, Liu X, Chen P, Cui Y, Liu J, Wang J, Liang G. Using "On/Off" (19)F NMR/Magnetic Resonance Imaging Signals to Sense Tyrosine Kinase/Phosphatase Activity in Vitro and in Cell Lysates. Anal Chem 2016; 88:3363-8. [PMID: 26901415 DOI: 10.1021/acs.analchem.6b00036] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Tyrosine kinase and phosphatase are two important, antagonistic enzymes in organisms. Development of noninvasive approach for sensing their activity with high spatial and temporal resolution remains challenging. Herein, we rationally designed a hydrogelator Nap-Phe-Phe(CF3)-Glu-Tyr-Ile-OH (1a) whose supramolecular hydrogel (i.e., Gel 1a) can be subjected to tyrosine kinase-directed disassembly, and its phosphate precursor Nap-Phe-Phe(CF3)-Glu-Tyr(H2PO3)-Ile-OH (1b), which can be subjected to alkaline phosphatase (ALP)-instructed self-assembly to form supramolecular hydrogel Gel 1b, respectively. Mechanic properties and internal fibrous networks of the hydrogels were characterized with rheology and cryo transmission electron microscopy (cryo-TEM). Disassembly/self-assembly of their corresponding supramolecular hydrogels conferring respective "On/Off" (19)F NMR/MRI signals were employed to sense the activity of these two important enzymes in vitro and in cell lysates for the first time. We anticipate that our new (19)F NMR/magnetic resonance imaging (MRI) method would facilitate pharmaceutical researchers to screen new inhibitors for these two enzymes without steric hindrance.
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Affiliation(s)
- Zhen Zheng
- CAS Key Laboratory of Soft Matter Chemistry, Hefei Science Center CAS, Department of Chemistry, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Hongbin Sun
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei, Anhui 230031, China
| | - Chen Hu
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei, Anhui 230031, China
| | - Gongyu Li
- CAS Key Laboratory of Soft Matter Chemistry, Hefei Science Center CAS, Department of Chemistry, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Xiaomei Liu
- CAS Key Laboratory of Soft Matter Chemistry, Hefei Science Center CAS, Department of Chemistry, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Peiyao Chen
- CAS Key Laboratory of Soft Matter Chemistry, Hefei Science Center CAS, Department of Chemistry, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Yusi Cui
- CAS Key Laboratory of Soft Matter Chemistry, Hefei Science Center CAS, Department of Chemistry, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Jing Liu
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei, Anhui 230031, China
| | - Junfeng Wang
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei, Anhui 230031, China
| | - Gaolin Liang
- CAS Key Laboratory of Soft Matter Chemistry, Hefei Science Center CAS, Department of Chemistry, University of Science and Technology of China , Hefei, Anhui 230026, China
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31
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Bar-Shir A, Liang Y, Chan KWY, Gilad AA, Bulte JWM. Supercharged green fluorescent proteins as bimodal reporter genes for CEST MRI and optical imaging. Chem Commun (Camb) 2015; 51:4869-71. [PMID: 25697683 DOI: 10.1039/c4cc10195b] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Superpositively charged mutants of green fluorescent protein (GFP) demonstrated a dramatically improved chemical exchange saturation transfer (CEST) MRI contrast compared to their wild type counterparts. The mutants +36 GFP and +48 GFP were successfully expressed in mammalian cells and retained part of their fluorescence, making them a new potential bimodal reporter gene.
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Affiliation(s)
- Amnon Bar-Shir
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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32
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Andrzejewska A, Nowakowski A, Janowski M, Bulte JWM, Gilad AA, Walczak P, Lukomska B. Pre- and postmortem imaging of transplanted cells. Int J Nanomedicine 2015; 10:5543-59. [PMID: 26366076 PMCID: PMC4562754 DOI: 10.2147/ijn.s83557] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Therapeutic interventions based on the transplantation of stem and progenitor cells have garnered increasing interest. This interest is fueled by successful preclinical studies for indications in many diseases, including the cardiovascular, central nervous, and musculoskeletal system. Further progress in this field is contingent upon access to techniques that facilitate an unambiguous identification and characterization of grafted cells. Such methods are invaluable for optimization of cell delivery, improvement of cell survival, and assessment of the functional integration of grafted cells. Following is a focused overview of the currently available cell detection and tracking methodologies that covers the entire spectrum from pre- to postmortem cell identification.
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Affiliation(s)
- Anna Andrzejewska
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Adam Nowakowski
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Miroslaw Janowski
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
- Department of Neurosurgery, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
- RusselI H Morgan Department of Radiology and Radiological Science, Division of Magnetic Resonance Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jeff WM Bulte
- RusselI H Morgan Department of Radiology and Radiological Science, Division of Magnetic Resonance Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Chemical & Biomolecular Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Assaf A Gilad
- RusselI H Morgan Department of Radiology and Radiological Science, Division of Magnetic Resonance Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Piotr Walczak
- RusselI H Morgan Department of Radiology and Radiological Science, Division of Magnetic Resonance Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Radiology, Faculty of Medical Sciences, University of Warmia and Mazury, Olsztyn, Poland
| | - Barbara Lukomska
- NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
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33
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Hingorani DV, Bernstein AS, Pagel MD. A review of responsive MRI contrast agents: 2005-2014. CONTRAST MEDIA & MOLECULAR IMAGING 2015; 10:245-65. [PMID: 25355685 PMCID: PMC4414668 DOI: 10.1002/cmmi.1629] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 09/06/2014] [Accepted: 09/18/2014] [Indexed: 12/18/2022]
Abstract
This review focuses on MRI contrast agents that are responsive to a change in a physiological biomarker. The response mechanisms are dependent on six physicochemical characteristics, including the accessibility of water to the agent, tumbling time, proton exchange rate, electron spin state, MR frequency or superparamagnetism of the agent. These characteristics can be affected by changes in concentrations or activities of enzymes, proteins, nucleic acids, metabolites, or metal ions, or changes in redox state, pH, temperature, or light. A total of 117 examples are presented, including ones that employ nuclei other than (1) H, which attests to the creativity of multidisciplinary research efforts to develop responsive MRI contrast agents.
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Affiliation(s)
- Dina V Hingorani
- Department of Chemistry and Biochemistry, University of Arizona, USA
| | - Adam S Bernstein
- Department of Biomedical Engineering, University of Arizona, USA
| | - Mark D Pagel
- Department of Chemistry and Biochemistry, University of Arizona, USA
- Department of Biomedical Engineering, University of Arizona, USA
- Department of Medical Imaging, University of Arizona, USA
- University of Arizona Cancer Center, University of Arizona, USA
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34
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Abstract
Molecular imaging plays an important role in the era of personalized medicine, especially with recent advances in magnetic resonance (MR) probes. While the first generation of these probes focused on maximizing contrast enhancement, a second generation of probes has been developed to improve the accumulation within specific tissues or pathologies, and the newest generation of agents is also designed to report on changes in physiological status and has been termed "smart" agents. This represents a paradigm switch from the previously commercialized gadolinium and iron oxide probes to probes with new capabilities, and leads to new challenges as scanner hardware needs to be adapted for detecting these probes. In this chapter, we highlight the unique features for all five different categories of MR probes, including the emerging chemical exchange saturation transfer, (19)F, and hyperpolarized probes, and describe the key physical properties and features motivating their design. As part of this comparison, the strengths and weaknesses of each category are discussed.
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Affiliation(s)
- Michael T McMahon
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA; The Russell H. Morgan Department of Radiology and Radiological Sciences, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
| | - Kannie W Y Chan
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA; The Russell H. Morgan Department of Radiology and Radiological Sciences, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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35
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Bar-Shir A, Bulte JWM, Gilad AA. Molecular engineering of nonmetallic biosensors for CEST MRI. ACS Chem Biol 2015; 10:1160-70. [PMID: 25730583 DOI: 10.1021/cb500923v] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Recent advancements in molecular and synthetic biology, combined with synthetic chemistry and biotechnology, have opened up new opportunities to engineer novel platforms that can monitor complex biological processes with various noninvasive imaging modalities. After decades of using gadolinium- or iron-based metallic sensors for MRI, the recently developed chemical exchange saturation transfer (CEST) contrast mechanism has created an opportunity for rational design, in silico, of nonmetallic biosensors for MRI. These biomolecules are either naturally occurring compounds (amino acids, sugars, nucleosides, native proteins) or can be artificially engineered (synthetic probes or recombinant proteins). They can be administered either as exogenous agents or can be genetically (over)expressed. Moreover, they can be precisely engineered to achieve the desired biochemical properties for fine tuning optimized imaging schemes. The availability of these agents marks the dawn of a new scientific era for molecular and cellular MRI.
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Affiliation(s)
- Amnon Bar-Shir
- Russell
H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Jeff W. M. Bulte
- Russell
H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
- F.M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21205, United States
- Department
of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
- Department of Chemical & Biomolecular Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21218, United States
| | - Assaf A. Gilad
- Russell
H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
- F.M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21205, United States
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36
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Minn I, Bar-Shir A, Yarlagadda K, Bulte JWM, Fisher PB, Wang H, Gilad AA, Pomper MG. Tumor-specific expression and detection of a CEST reporter gene. Magn Reson Med 2015; 74:544-9. [PMID: 25919119 DOI: 10.1002/mrm.25748] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 03/25/2015] [Accepted: 04/02/2015] [Indexed: 12/19/2022]
Abstract
PURPOSE To develop an imaging tool that enables the detection of malignant tissue with enhanced specificity using the exquisite spatial resolution of MRI. METHODS Two mammalian gene expression vectors were created for the expression of the lysine-rich protein (LRP) under the control of the cytomegalovirus (CMV) promoter and the progression elevated gene-3 promoter (PEG-3 promoter) for constitutive and tumor-specific expression of LRP, respectively. Using those vectors, stable cell lines of rat 9L glioma, 9L(CMV-LRP) and 9L(PEG-LRP) , were established and tested for CEST contrast in vitro and in vivo. RESULTS 9L(PEG-LRP) cells showed increased CEST contrast compared with 9L cells in vitro. Both 9L(CMV-LRP) and 9L(PEG-LRP) cells were capable of generating tumors in the brains of mice, with a similar growth rate to tumors derived from wild-type 9L cells. An increase in CEST contrast was clearly visible in tumors derived from both 9L(CMV-LRP) and 9L(PEG-LRP) cells at 3.4 ppm. CONCLUSION The PEG-3 promoter:LRP system can be used as a cancer-specific, molecular-genetic imaging reporter system in vivo. Because of the ubiquity of MR imaging in clinical practice, sensors of this class can be used to translate molecular-genetic imaging rapidly.
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Affiliation(s)
- Il Minn
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Amnon Bar-Shir
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Cellular Imaging Section, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Keerthi Yarlagadda
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jeff W M Bulte
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Cellular Imaging Section, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Paul B Fisher
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia, USA.,VCU Institute of Molecular Medicine, Virginia Commonwealth University, Richmond, Virginia, USA.,VCU Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Hao Wang
- Division of Biostatistics and Bioinformatics, The Johns Hopkins University, Baltimore, Maryland, USA
| | - Assaf A Gilad
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Cellular Imaging Section, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Martin G Pomper
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University, Baltimore, Maryland, USA
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37
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Srivastava AK, Kadayakkara DK, Bar-Shir A, Gilad AA, McMahon MT, Bulte JWM. Advances in using MRI probes and sensors for in vivo cell tracking as applied to regenerative medicine. Dis Model Mech 2015; 8:323-36. [PMID: 26035841 PMCID: PMC4381332 DOI: 10.1242/dmm.018499] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The field of molecular and cellular imaging allows molecules and cells to be visualized in vivo non-invasively. It has uses not only as a research tool but in clinical settings as well, for example in monitoring cell-based regenerative therapies, in which cells are transplanted to replace degenerating or damaged tissues, or to restore a physiological function. The success of such cell-based therapies depends on several critical issues, including the route and accuracy of cell transplantation, the fate of cells after transplantation, and the interaction of engrafted cells with the host microenvironment. To assess these issues, it is necessary to monitor transplanted cells non-invasively in real-time. Magnetic resonance imaging (MRI) is a tool uniquely suited to this task, given its ability to image deep inside tissue with high temporal resolution and sensitivity. Extraordinary efforts have recently been made to improve cellular MRI as applied to regenerative medicine, by developing more advanced contrast agents for use as probes and sensors. These advances enable the non-invasive monitoring of cell fate and, more recently, that of the different cellular functions of living cells, such as their enzymatic activity and gene expression, as well as their time point of cell death. We present here a review of recent advancements in the development of these probes and sensors, and of their functioning, applications and limitations.
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Affiliation(s)
- Amit K Srivastava
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Deepak K Kadayakkara
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Amnon Bar-Shir
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Assaf A Gilad
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Michael T McMahon
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Jeff W M Bulte
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA. Department of Chemical & Biomolecular Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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38
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Oskolkov N, Bar-Shir A, Chan KW, Song X, van Zijl PC, Bulte JW, Gilad AA, McMahon MT. Biophysical Characterization of Human Protamine-1 as a Responsive CEST MR Contrast Agent. ACS Macro Lett 2015; 4:34-38. [PMID: 25642384 PMCID: PMC4307908 DOI: 10.1021/mz500681y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 12/15/2014] [Indexed: 11/28/2022]
Abstract
![]()
The protamines are a low-molecular-weight,
arginine-rich family
of nuclear proteins that protect chromosomal DNA in germ cells by
packing it densely using electrostatic interactions. Human protamine-1
(hPRM1) has been developed as a magnetic resonance imaging (MRI) chemical
exchange saturation transfer (CEST) reporter gene, based on a sequence
that is approximately 50% arginine, which has a side chain with rapidly
exchanging protons. In this study, we have synthesized hPRM1 and determined
how its CEST MRI contrast varies as a function of pH, phosphorylation
state, and upon noncovalent interaction with nucleic acids and heparin
(as antagonist). CEST contrast was found to be highly sensitive to
phosphorylation on serine residues, intra- and intermolecular disulfide
bridge formation, and the binding of negatively charged nucleotides
and heparin. In addition, the nucleotide binding constants (Keq) for the protamines were determined through
plotting the molar concentration of heparin versus CEST contrast and
compared between hPRM1 and salmon protamine. Taken together, these
findings are important for explaining the CEST contrast of existing
arginine-rich probes as well as serving as a guideline for designing
new genetic or synthetic probes.
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Affiliation(s)
- Nikita Oskolkov
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland United States
- F.M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland United States
| | - Amnon Bar-Shir
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Baltimore, Maryland United States
| | - Kannie W.Y. Chan
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland United States
- F.M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Baltimore, Maryland United States
| | - Xiaolei Song
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland United States
- F.M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland United States
| | - Peter C.M. van Zijl
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland United States
- F.M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland United States
| | - Jeff W.M. Bulte
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland United States
- F.M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Baltimore, Maryland United States
| | - Assaf A. Gilad
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland United States
- F.M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Baltimore, Maryland United States
| | - Michael T. McMahon
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland United States
- F.M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland United States
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39
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Liang Y, Bar-Shir A, Song X, Gilad AA, Walczak P, Bulte JWM. Label-free imaging of gelatin-containing hydrogel scaffolds. Biomaterials 2014; 42:144-50. [PMID: 25542802 DOI: 10.1016/j.biomaterials.2014.11.050] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/13/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
Abstract
Composite hyaluronic acid (HA) hydrogels containing gelatin are used in regenerative medicine as tissue-mimicking scaffolds for improving stem cell survival. Once implanted, it is assumed that these biomaterials disintegrate over time, but at present there is no non-invasive imaging technique available with which such degradation can be directly monitored in vivo. We show here the potential of chemical exchange saturation transfer magnetic resonance imaging (CEST MRI) as a label-free non-invasive imaging technique to monitor dynamic changes in scaffold composition in vivo. The CEST properties of the three individual hydrogel components (HA, GelinS, and polyethylene glycol diacrylate) were first measured in vitro. The complete hydrogel was then injected into the brain of immunodeficient rag2(-/-) mice and CEST MR images were obtained at day 1 and 7 post-transplantation. In vitro, GelinS gave the strongest CEST signal at 3.6 ppm offset from the water peak, originating from the amide protons present in gelatin. In vivo, a significant decrease in CEST signal was observed at 1 week post-implantation. These results were consistent with the biodegradation of the GelinS component, as validated by fluorescent microscopy of implanted hydrogels containing Alexa Fluor 488-labeled GelinS. Our label-free imaging approach should be useful for further development of hydrogel formulations with improved composition and stability.
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Affiliation(s)
- Yajie Liang
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Amnon Bar-Shir
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Xiaolei Song
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Assaf A Gilad
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Piotr Walczak
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jeff W M Bulte
- Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Dept. of Chemical & Biomolecular Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Dept. of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Dept. of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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40
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Vande Velde G, Himmelreich U, Neeman M. Reporter gene approaches for mapping cell fate decisions by MRI: promises and pitfalls. CONTRAST MEDIA & MOLECULAR IMAGING 2014; 8:424-31. [PMID: 24375898 DOI: 10.1002/cmmi.1590] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 11/29/2013] [Indexed: 12/15/2022]
Abstract
The central dogma of molecular biology, namely the process by which information encoded in the DNA serves as the template for transcriptional activation of specific mRNA resulting in temporal and spatial control of the translation of specific proteins, stands at the basis of normal and pathological cellular processes. Serving as the primary mechanism linking genotype to phenotype, it is clearly of significant interest for in vivo imaging. While classically, imaging revolutionized the ability to phenotype the anatomical and physiological impact of induction of changes in gene expression, the preceding molecular events remained invisible. Reporter gene-based imaging techniques provide a window for in vivo visualization of such transcriptional activation events. In addition to the widespread use of fluorescent and bioluminescent reporter genes and development of a number of reporter genes for positron emission tomography (PET) imaging, there has been significant progress in the development of reporter genes for MRI. With the development of strategies for cellular based therapies, such imaging tools could become central components for personalized patient monitoring.
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Affiliation(s)
- Greetje Vande Velde
- Biomedical MRI, KU Leuven, O&N I Herestraat 49 - box 505, 3000, Leuven, Belgium
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41
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Hingorani DV, Yoo B, Bernstein AS, Pagel MD. Detecting enzyme activities with exogenous MRI contrast agents. Chemistry 2014; 20:9840-50. [PMID: 24990812 PMCID: PMC4117811 DOI: 10.1002/chem.201402474] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This review focuses on exogenous magnetic resonance imaging (MRI) contrast agents that are responsive to enzyme activity. Enzymes can catalyze a change in water access, rotational tumbling time, the proximity of a (19)F-labeled ligand, the aggregation state, the proton chemical-exchange rate between the agent and water, or the chemical shift of (19)F, (31)P, (13)C or a labile (1)H of an agent, all of which can be used to detect enzyme activity. The variety of agents attests to the creativity in developing enzyme-responsive MRI contrast agents.
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Affiliation(s)
- Dina V. Hingorani
- Department of Chemistry and Biochemisty University of Arizona 1515 N. Campbell Ave. Tucson, AZ, USA Fax: (520)-626-0194
| | - Byunghee Yoo
- MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Adam S. Bernstein
- Department of Biomedical Engineering University of Arizona 1515 N. Campbell Ave. Tucson, AZ, USA
| | - Mark D. Pagel
- Department of Chemistry and Biochemisty University of Arizona 1515 N. Campbell Ave. Tucson, AZ, USA Fax: (520)-626-0194
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42
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Song X, Yang X, Ray Banerjee S, Pomper MG, McMahon MT. Anthranilic acid analogs as diamagnetic CEST MRI contrast agents that feature an intramolecular-bond shifted hydrogen. CONTRAST MEDIA & MOLECULAR IMAGING 2014; 10:74-80. [PMID: 24771546 DOI: 10.1002/cmmi.1597] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 01/22/2014] [Accepted: 01/29/2014] [Indexed: 12/23/2022]
Abstract
Diamagnetic chemical exchange saturation transfer (diaCEST) agents are a new class of imaging agents, which have unique magnetic resonance (MR) properties similar to agents used for optical imaging. Here we present a series of anthranilic acid analogs as examples of diaCEST agents that feature an exchangeable proton shifted downfield, namely, an intramolecular-bond shifted hydrogen (IM-SHY), which produces significant and tunable contrast at frequencies of 4.8-9.3 ppm from water. Five analogs of N-sulfonyl anthranilic acids are all highly soluble and produced similar CEST contrast at ~6-8 ppm. We also discovered that flufenamic acid, a commercial nonsteroidal anti-inflammatory drug, displayed CEST contrast at 4.8 ppm. For these N-H IM-SHY agents, the contrast produced was insensitive to pH, making them complementary to existing diaCEST probes. This initial IM-SHY library includes the largest reported shifts for N-H protons on small organic diaCEST agents, and should find use as multifrequency MR agents for in vivo applications.
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Affiliation(s)
- Xiaolei Song
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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43
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Westmeyer GG, Emer Y, Lintelmann J, Jasanoff A. MRI-based detection of alkaline phosphatase gene reporter activity using a porphyrin solubility switch. ACTA ACUST UNITED AC 2014; 21:422-9. [PMID: 24613020 DOI: 10.1016/j.chembiol.2014.01.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 01/08/2014] [Accepted: 01/13/2014] [Indexed: 12/23/2022]
Abstract
The ability to map patterns of gene expression noninvasively in living animals could have impact in many areas of biology. Reporter systems compatible with MRI could be particularly valuable, but existing strategies tend to lack sensitivity or specificity. Here we address the challenge of MRI-based gene mapping using the reporter enzyme secreted alkaline phosphatase (SEAP), in conjunction with a water-soluble metalloporphyrin contrast agent. SEAP cleaves the porphyrin into an insoluble product that accumulates at sites of enzyme expression and can be visualized by MRI and optical absorbance. The contrast mechanism functions in vitro, in brain slices, and in animals. The system also provides the possibility of readout both in the living animal and by postmortem histology, and it notably does not require intracellular delivery of the contrast agent. The solubility switch mechanism used to detect SEAP could be adapted for imaging of additional reporter enzymes or endogenous targets.
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Affiliation(s)
- Gil G Westmeyer
- Departments of Brain & Cognitive Sciences, Biological Engineering, and Nuclear Science & Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room 16-561, Cambridge, MA 02139, USA; Department of Nuclear Medicine, Technische Universität München, 81675 Munich, Germany; Institutes of Biological and Medical Imaging and Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Munich/Neuherberg, Germany
| | - Yelena Emer
- Departments of Brain & Cognitive Sciences, Biological Engineering, and Nuclear Science & Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room 16-561, Cambridge, MA 02139, USA
| | - Jutta Lintelmann
- Comprehensive Molecular Analytics Cooperation Group, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Munich/Neuherberg, Germany
| | - Alan Jasanoff
- Departments of Brain & Cognitive Sciences, Biological Engineering, and Nuclear Science & Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room 16-561, Cambridge, MA 02139, USA.
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44
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Bar-Shir A, Liu G, Chan KW, Oskolkov N, Song X, Yadav NN, Walczak P, McMahon MT, van Zijl PCM, Bulte JWM, Gilad AA. Human protamine-1 as an MRI reporter gene based on chemical exchange. ACS Chem Biol 2014; 9:134-8. [PMID: 24138139 DOI: 10.1021/cb400617q] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Genetically engineered reporters have revolutionized the understanding of many biological processes. MRI-based reporter genes can dramatically improve our ability to monitor dynamic gene expression and allow coregistration of subcellular genetic information with high-resolution anatomical images. We have developed a biocompatible MRI reporter gene based on a human gene, the human protamine-1 (hPRM1). The arginine-rich hPRM1 (47% arginine residues) generates high MRI contrast based on the chemical exchange saturation transfer (CEST) contrast mechanism. The 51 amino acid-long hPRM1 protein was fully synthesized using microwave-assisted technology, and the CEST characteristics of this protein were compared to other CEST-based contrast agents. Both bacterial and human cells were engineered to express an optimized hPRM1 gene and showed higher CEST contrast compared to controls. Live cells expressing the hPRM1 reporter gene, and embedded in three-dimensional culture, also generated higher CEST contrast compared to wild-type live cells.
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Affiliation(s)
- Amnon Bar-Shir
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
| | - Guanshu Liu
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
| | - Kannie W.Y. Chan
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
| | - Nikita Oskolkov
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
| | - Xiaolei Song
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
| | - Nirbhay N. Yadav
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
| | - Piotr Walczak
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
| | - Michael T. McMahon
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
| | - Peter C. M. van Zijl
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
| | - Jeff W. M. Bulte
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
- Department
of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- Department of Chemical & Biomolecular Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
| | - Assaf A. Gilad
- Russell
H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- Cellular
Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, United States
- F. M.
Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland 21231, United States
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45
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Abstract
The increasing complexity of in vivo imaging technologies, coupled with the development of cell therapies, has fuelled a revolution in immune cell tracking in vivo. Powerful magnetic resonance imaging (MRI) methods are now being developed that use iron oxide- and ¹⁹F-based probes. These MRI technologies can be used for image-guided immune cell delivery and for the visualization of immune cell homing and engraftment, inflammation, cell physiology and gene expression. MRI-based cell tracking is now also being applied to evaluate therapeutics that modulate endogenous immune cell recruitment and to monitor emerging cellular immunotherapies. These recent uses show that MRI has the potential to be developed in many applications to follow the fate of immune cells in vivo.
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Yang X, Song X, Li Y, Liu G, Banerjee SR, Pomper MG, McMahon MT. Salicylic acid and analogues as diaCEST MRI contrast agents with highly shifted exchangeable proton frequencies. Angew Chem Int Ed Engl 2013; 52:8116-9. [PMID: 23794432 PMCID: PMC3819166 DOI: 10.1002/anie.201302764] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 05/27/2013] [Indexed: 12/27/2022]
Affiliation(s)
- Xing Yang
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, Maryland 21287 (USA)
| | - Xiaolei Song
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, Maryland 21287 (USA)
| | - Yuguo Li
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, Maryland 21287 (USA)
| | - Guanshu Liu
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, Maryland 21287 (USA); F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway Ave., Baltimore, Maryland 21287 (USA)
| | - Sangeeta Ray Banerjee
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, Maryland 21287 (USA)
| | - Martin G. Pomper
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, Maryland 21287 (USA)
| | - Michael T. McMahon
- The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, 991 N. Broadway Baltimore, Maryland 21287 (USA); F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway Ave., Baltimore, Maryland 21287 (USA)
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47
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Yang X, Song X, Li Y, Liu G, Ray Banerjee S, Pomper MG, McMahon MT. Salicylic Acid and Analogues as diaCEST MRI Contrast Agents with Highly Shifted Exchangeable Proton Frequencies. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201302764] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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