1
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Chacko AN, Miller ADC, Dhanabalan KM, Mukherjee A. Exploring the potential of water channels for developing genetically encoded reporters and biosensors for diffusion-weighted MRI. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 365:107743. [PMID: 39053029 DOI: 10.1016/j.jmr.2024.107743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 07/02/2024] [Accepted: 07/17/2024] [Indexed: 07/27/2024]
Abstract
Genetically encoded reporters for magnetic resonance imaging (MRI) offer a valuable technology for making molecular-scale measurements of biological processes within living organisms with high anatomical resolution and whole-organ coverage without relying on ionizing radiation. However, most MRI reporters rely on synthetic contrast agents, typically paramagnetic metals and metal complexes, which often need to be supplemented exogenously to create optimal contrast. To eliminate the need for synthetic contrast agents, we previously introduced aquaporin-1, a mammalian water channel, as a new reporter gene for the fully autonomous detection of genetically labeled cells using diffusion-weighted MRI. In this study, we aimed to expand the toolbox of diffusion-based genetic reporters by modulating aquaporin membrane trafficking and harnessing the evolutionary diversity of water channels across species. We identified a number of new water channels that functioned as diffusion-weighted reporter genes. In addition, we show that loss-of-function variants of yeast and human aquaporins can be leveraged to design first-in-class diffusion-based sensors for detecting the activity of a model protease within living cells.
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Affiliation(s)
- Asish N Chacko
- Department of Chemistry, University of California, Santa Barbara, CA 93106-5080, USA
| | - Austin D C Miller
- Biomolecular Science and Engineering Graduate Program, University of California, Santa Barbara, CA 93106-5080, USA
| | - Kaamini M Dhanabalan
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106-5080, USA
| | - Arnab Mukherjee
- Department of Chemistry, University of California, Santa Barbara, CA 93106-5080, USA; Biomolecular Science and Engineering Graduate Program, University of California, Santa Barbara, CA 93106-5080, USA; Department of Chemical Engineering, University of California, Santa Barbara, CA 93106-5080, USA; Department of Bioengineering, University of California, Santa Barbara, CA 93106-5080, USA.
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2
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Rallapalli H, McCall EC, Koretsky AP. Genetic control of MRI contrast using the manganese transporter Zip14. Magn Reson Med 2024; 92:820-835. [PMID: 38573932 PMCID: PMC11142883 DOI: 10.1002/mrm.29993] [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: 09/22/2023] [Revised: 11/15/2023] [Accepted: 12/12/2023] [Indexed: 04/06/2024]
Abstract
PURPOSE Gene-expression reporter systems, such as green fluorescent protein, have been instrumental to understanding biological processes in living organisms at organ system, tissue, cell, and molecular scales. More than 30 years of work on developing MRI-visible gene-expression reporter systems has resulted in a variety of clever application-specific methods. However, these techniques have not yet been widely adopted, so a general-purpose expression reporter is still required. Here, we demonstrate that the manganese ion transporter Zip14 is an in vivo MRI-visible, flexible, and robust gene-expression reporter to meet this need. METHODS Plasmid constructs consisting of a cell type-specific promoter, gene coding for human Zip14, and a histology-visible tag were packaged into adeno-associated viruses. These viruses were intracranially injected into the mouse brain. Serial in vivo MRI was performed using a vendor-supplied 3D-MPRAGE sequence. No additional contrast agents were administered. Animals were sacrificed after the last imaging timepoint for immunohistological validation. RESULTS Neuron-specific overexpression of Zip14 produced substantial and long-lasting changes in MRI contrast. Using appropriate viruses enabled both anterograde and retrograde neural tracing. Expression of Zip14 in astrocytes also enabled MRI of glia populations in the living mammalian brain. CONCLUSIONS The flexibility of this system as an MRI-visible gene-expression reporter will enable many applications of serial, high-resolution imaging of gene expression for basic science and therapy development.
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Affiliation(s)
- Harikrishna Rallapalli
- Section on Plasticity and Imaging of the Nervous System, NINDS/NIH, Bethesda, Maryland, USA
| | - Eleanor C McCall
- Section on Plasticity and Imaging of the Nervous System, NINDS/NIH, Bethesda, Maryland, USA
| | - Alan P Koretsky
- Section on Plasticity and Imaging of the Nervous System, NINDS/NIH, Bethesda, Maryland, USA
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3
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Huang Y, Chen X, Zhu Z, Mukherjee A. A Dual-Gene Reporter-Amplifier Architecture for Enhancing the Sensitivity of Molecular MRI by Water Exchange. Chembiochem 2024; 25:e202400087. [PMID: 38439618 DOI: 10.1002/cbic.202400087] [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: 01/30/2024] [Revised: 03/04/2024] [Accepted: 03/05/2024] [Indexed: 03/06/2024]
Abstract
The development of genetic reporters for magnetic resonance imaging (MRI) is essential for investigating biological functions in vivo. However, current MRI reporters have low sensitivity, making it challenging to create significant contrast against the tissue background, especially when only a small fraction of cells express the reporter. To overcome this limitation, we developed an approach for amplifying the sensitivity of molecular MRI by combining a chemogenetic contrast mechanism with a biophysical approach to increase water diffusion through the co-expression of a dual-gene construct comprising an organic anion transporting polypeptide, Oatp1b3, and a water channel, Aqp1. We first show that the expression of Aqp1 amplifies MRI contrast in cultured cells engineered to express Oatp1b3. We demonstrate that the contrast amplification is caused by Aqp1-driven increase in water exchange, which provides the gadolinium ions internalized by Oatp1b3-expressing cells with access to a larger water pool compared with exchange-limited conditions. We further show that our methodology allows cells to be detected using approximately 10-fold lower concentrations of gadolinium than that in the Aqp1-free scenario. Finally, we show that our approach enables the imaging of mixed-cell cultures containing a low fraction of Oatp1b3-labeled cells that are undetectable on the basis of Oatp1b3 expression alone.
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Affiliation(s)
- Yimeng Huang
- Department of Chemistry, University of California, Santa Barbara, CA 93106-5080
| | - Xinyue Chen
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106-5080
| | - Ziyue Zhu
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106-5080
| | - Arnab Mukherjee
- Department of Chemistry, University of California, Santa Barbara, CA 93106-5080
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106-5080
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106-5080
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4
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Miller ADC, Chowdhury SP, Hanson HW, Linderman SK, Ghasemi HI, Miller WD, Morrissey MA, Richardson CD, Gardner BM, Mukherjee A. Engineering water exchange is a safe and effective method for magnetic resonance imaging in diverse cell types. J Biol Eng 2024; 18:30. [PMID: 38649904 PMCID: PMC11035135 DOI: 10.1186/s13036-024-00424-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 04/08/2024] [Indexed: 04/25/2024] Open
Abstract
Aquaporin-1 (Aqp1), a water channel, has garnered significant interest for cell-based medicine and in vivo synthetic biology due to its ability to be genetically encoded to produce magnetic resonance signals by increasing the rate of water diffusion in cells. However, concerns regarding the effects of Aqp1 overexpression and increased membrane diffusivity on cell physiology have limited its widespread use as a deep-tissue reporter. In this study, we present evidence that Aqp1 generates strong diffusion-based magnetic resonance signals without adversely affecting cell viability or morphology in diverse cell lines derived from mice and humans. Our findings indicate that Aqp1 overexpression does not induce ER stress, which is frequently associated with heterologous expression of membrane proteins. Furthermore, we observed that Aqp1 expression had no detrimental effects on native biological activities, such as phagocytosis, immune response, insulin secretion, and tumor cell migration in the analyzed cell lines. These findings should serve to alleviate any lingering safety concerns regarding the utilization of Aqp1 as a genetic reporter and should foster its broader application as a noninvasive reporter for in vivo studies.
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Affiliation(s)
- Austin D C Miller
- Biomolecular Science and Engineering Graduate Program, University of California, Santa Barbara, CA, 93106, USA
| | - Soham P Chowdhury
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA, 93106, USA
| | - Hadley W Hanson
- Biomolecular Science and Engineering Graduate Program, University of California, Santa Barbara, CA, 93106, USA
| | - Sarah K Linderman
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA, 93106, USA
| | - Hannah I Ghasemi
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA, 93106, USA
| | - Wyatt D Miller
- Biomolecular Science and Engineering Graduate Program, University of California, Santa Barbara, CA, 93106, USA
| | - Meghan A Morrissey
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA, 93106, USA
| | - Chris D Richardson
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA, 93106, USA
| | - Brooke M Gardner
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA, 93106, USA
| | - Arnab Mukherjee
- Biomolecular Science and Engineering Graduate Program, University of California, Santa Barbara, CA, 93106, USA.
- Department of Chemical Engineering, University of California, Santa Barbara, CA, 93106, USA.
- Department of Bioengineering, University of California, Santa Barbara, CA, 93106, USA.
- Department of Chemistry, University of California, Santa Barbara, CA, 93106, USA.
- Neuroscience Research Institute, University of California, Santa Barbara, CA, 93106, USA.
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5
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Huang Y, Chen X, Zhu Z, Mukherjee A. A dual-gene reporter-amplifier architecture for enhancing the sensitivity of molecular MRI by water exchange. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.22.576672. [PMID: 38328134 PMCID: PMC10849537 DOI: 10.1101/2024.01.22.576672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
The development of genetic reporters for magnetic resonance imaging (MRI) is essential for investigating biological functions in intact animals. However, current MRI reporters have low sensitivity, making it challenging to create significant contrast against the tissue background, especially when only a small percentage of cells express the reporter. To overcome this limitation, we developed an approach that amplifies signals by co-expressing an MRI reporter gene, Oatp1b3, with a water channel, aquaporin-1 (Aqp1). We first show that the expression of Aqp1 amplifies the paramagnetic relaxation effect of Oatp1b3 by facilitating transmembrane water exchange. This mechanism provides Oatp1b3-expressing cells with access to a larger water pool compared with typical exchange-limited conditions. We further demonstrated that our methodology allows dual-labeled cells to be detected using approximately 10-fold lower concentrations of contrast agent than that in the Aqp1-free scenario. Finally, we show that our approach enables the imaging of mixed-cell populations containing a low fraction of Oatp1b3-labeled cells that are otherwise undetectable based on Oatp1b3 expression alone.
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Affiliation(s)
| | - Xinyue Chen
- Department of Molecular, Cellular, and Developmental Biology
| | - Ziyue Zhu
- Department of Molecular, Cellular, and Developmental Biology
| | - Arnab Mukherjee
- Department of Chemistry
- Department of Molecular, Cellular, and Developmental Biology
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6
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Chacko AN, Miller AD, Dhanabalan KM, Mukherjee A. Exploring the potential of water channels for developing MRI reporters and sensors without the need for exogenous contrast agents. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.21.576580. [PMID: 38328035 PMCID: PMC10849501 DOI: 10.1101/2024.01.21.576580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Genetically encoded reporters for magnetic resonance imaging (MRI) offer a valuable technology for making molecular-scale measurements of biological processes within living organisms with high anatomical resolution and whole-organ coverage without relying on ionizing radiation. However, most MRI reporters rely on contrast agents, typically paramagnetic metals and metal complexes, which often need to be supplemented exogenously to create optimal contrast. To eliminate the need for contrast agents, we previously introduced aquaporin-1, a mammalian water channel, as a new reporter gene for the fully autonomous detection of genetically labeled cells using diffusion-weighted MRI. In this study, we aimed to expand the toolbox of diffusion-based genetic reporters by modulating aquaporin membrane trafficking and harnessing the evolutionary diversity of water channels across species. We identified a number of new water channels that functioned as diffusion-weighted reporter genes. In addition, we show that loss-of-function variants of yeast and human aquaporins can be leveraged to design first-in-class diffusion-based sensors for detecting the activity of a model protease within living cells.
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Affiliation(s)
| | | | | | - Arnab Mukherjee
- Department of Chemistry
- Biomolecular Science and Engineering Graduate Program
- Department of Chemical Engineering
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7
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Miller ADC, Chowdhury SP, Hanson HW, Linderman SK, Ghasemi HI, Miller WD, Morrissey MA, Richardson CD, Gardner BM, Mukherjee A. Engineering water exchange is a safe and effective method for magnetic resonance imaging in diverse cell types. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.07.566095. [PMID: 37986852 PMCID: PMC10659288 DOI: 10.1101/2023.11.07.566095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Aquaporin-1 (Aqp1), a water channel, has garnered significant interest for cell-based medicine and in vivo synthetic biology due to its ability to be genetically encoded to produce magnetic resonance signals by increasing the rate of water diffusion in cells. However, concerns regarding the effects of Aqp1 overexpression and increased membrane diffusivity on cell physiology have limited its widespread use as a deep-tissue reporter. In this study, we present evidence that Aqp1 generates strong diffusion-based magnetic resonance signals without adversely affecting cell viability or morphology in diverse cell lines derived from mice and humans. Our findings indicate that Aqp1 overexpression does not induce ER stress, which is frequently associated with heterologous expression of membrane proteins. Furthermore, we observed that Aqp1 expression had no detrimental effects on native biological activities, such as phagocytosis, immune response, insulin secretion, and tumor cell migration in the analyzed cell lines. These findings should serve to alleviate any lingering safety concerns regarding the utilization of Aqp1 as a genetic reporter and should foster its broader application as a noninvasive reporter for in vivo studies.
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Affiliation(s)
- Austin D C Miller
- Biomolecular Science and Engineering Graduate Program, University of California, Santa Barbara, CA 93106, USA
| | - Soham P Chowdhury
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - Hadley W Hanson
- Biomolecular Science and Engineering Graduate Program, University of California, Santa Barbara, CA 93106, USA
| | - Sarah K Linderman
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - Hannah I Ghasemi
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - Wyatt D Miller
- Biomolecular Science and Engineering Graduate Program, University of California, Santa Barbara, CA 93106, USA
| | - Meghan A Morrissey
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - Chris D Richardson
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - Brooke M Gardner
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - Arnab Mukherjee
- Biomolecular Science and Engineering Graduate Program, University of California, Santa Barbara, CA 93106, USA
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, USA
- Department of Bioengineering, University of California, Santa Barbara, CA 93106, USA
- Department of Chemistry, University of California, Santa Barbara, CA 93106, USA
- Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA
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8
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Dan Q, Jiang X, Wang R, Dai Z, Sun D. Biogenic Imaging Contrast Agents. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2207090. [PMID: 37401173 PMCID: PMC10477908 DOI: 10.1002/advs.202207090] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 06/08/2023] [Indexed: 07/05/2023]
Abstract
Imaging contrast agents are widely investigated in preclinical and clinical studies, among which biogenic imaging contrast agents (BICAs) are developing rapidly and playing an increasingly important role in biomedical research ranging from subcellular level to individual level. The unique properties of BICAs, including expression by cells as reporters and specific genetic modification, facilitate various in vitro and in vivo studies, such as quantification of gene expression, observation of protein interactions, visualization of cellular proliferation, monitoring of metabolism, and detection of dysfunctions. Furthermore, in human body, BICAs are remarkably helpful for disease diagnosis when the dysregulation of these agents occurs and can be detected through imaging techniques. There are various BICAs matched with a set of imaging techniques, including fluorescent proteins for fluorescence imaging, gas vesicles for ultrasound imaging, and ferritin for magnetic resonance imaging. In addition, bimodal and multimodal imaging can be realized through combining the functions of different BICAs, which helps overcome the limitations of monomodal imaging. In this review, the focus is on the properties, mechanisms, applications, and future directions of BICAs.
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Affiliation(s)
- Qing Dan
- Shenzhen Key Laboratory for Drug Addiction and Medication SafetyDepartment of UltrasoundInstitute of Ultrasonic MedicinePeking University Shenzhen HospitalShenzhen Peking University‐The Hong Kong University of Science and Technology Medical CenterShenzhen518036P. R. China
| | - Xinpeng Jiang
- Department of Biomedical EngineeringCollege of Future TechnologyPeking UniversityBeijing100871P. R. China
| | - Run Wang
- Shenzhen Key Laboratory for Drug Addiction and Medication SafetyDepartment of UltrasoundInstitute of Ultrasonic MedicinePeking University Shenzhen HospitalShenzhen Peking University‐The Hong Kong University of Science and Technology Medical CenterShenzhen518036P. R. China
| | - Zhifei Dai
- Department of Biomedical EngineeringCollege of Future TechnologyPeking UniversityBeijing100871P. R. China
| | - Desheng Sun
- Shenzhen Key Laboratory for Drug Addiction and Medication SafetyDepartment of UltrasoundInstitute of Ultrasonic MedicinePeking University Shenzhen HospitalShenzhen Peking University‐The Hong Kong University of Science and Technology Medical CenterShenzhen518036P. R. China
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9
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Rallapalli H, Bayin NS, Goldman H, Maric D, Nieman BJ, Koretsky AP, Joyner AL, Turnbull DH. Cell specificity of Manganese-enhanced MRI signal in the cerebellum. Neuroimage 2023; 276:120198. [PMID: 37245561 PMCID: PMC10330770 DOI: 10.1016/j.neuroimage.2023.120198] [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: 03/23/2023] [Revised: 05/19/2023] [Accepted: 05/25/2023] [Indexed: 05/30/2023] Open
Abstract
Magnetic Resonance Imaging (MRI) resolution continues to improve, making it important to understand the cellular basis for different MRI contrast mechanisms. Manganese-enhanced MRI (MEMRI) produces layer-specific contrast throughout the brain enabling in vivo visualization of cellular cytoarchitecture, particularly in the cerebellum. Due to the unique geometry of the cerebellum, especially near the midline, 2D MEMRI images can be acquired from a relatively thick slice by averaging through areas of uniform morphology and cytoarchitecture to produce very high-resolution visualization of sagittal planes. In such images, MEMRI hyperintensity is uniform in thickness throughout the anterior-posterior axis of sagittal sections and is centrally located in the cerebellar cortex. These signal features suggested that the Purkinje cell layer, which houses the cell bodies of the Purkinje cells and the Bergmann glia, is the source of hyperintensity. Despite this circumstantial evidence, the cellular source of MRI contrast has been difficult to define. In this study, we quantified the effects of selective ablation of Purkinje cells or Bergmann glia on cerebellar MEMRI signal to determine whether signal could be assigned to one cell type. We found that the Purkinje cells, not the Bergmann glia, are the primary of source of the enhancement in the Purkinje cell layer. This cell-ablation strategy should be useful for determining the cell specificity of other MRI contrast mechanisms.
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Affiliation(s)
- Harikrishna Rallapalli
- Department of Radiology, NYU Langone Radiology - Center for Biomedical Imaging, New York University School of Medicine, 660 First Avenue, New York, NY 10016, United States; National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - N Sumru Bayin
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, United States; Gurdon Institute, University of Cambridge, UK; Department of Physiology, Development and Neuroscience, University of Cambridge, UK
| | - Hannah Goldman
- Department of Radiology, NYU Langone Radiology - Center for Biomedical Imaging, New York University School of Medicine, 660 First Avenue, New York, NY 10016, United States
| | - Dragan Maric
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Brian J Nieman
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Canada; Translational Medicine, The Hospital for Sick Children, Toronto, Canada; Medical Biophysics, University of Toronto, Toronto, Canada; Ontario Institute for Cancer Research, Toronto, Canada
| | - Alan P Koretsky
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Alexandra L Joyner
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, United States
| | - Daniel H Turnbull
- Department of Radiology, NYU Langone Radiology - Center for Biomedical Imaging, New York University School of Medicine, 660 First Avenue, New York, NY 10016, United States.
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10
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Cheng HLM. A primer on in vivo cell tracking using MRI. Front Med (Lausanne) 2023; 10:1193459. [PMID: 37324153 PMCID: PMC10264782 DOI: 10.3389/fmed.2023.1193459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 05/12/2023] [Indexed: 06/17/2023] Open
Abstract
Cell tracking by in vivo magnetic resonance imaging (MRI) offers a collection of multiple advantages over other imaging modalities, including high spatial resolution, unlimited depth penetration, 3D visualization, lack of ionizing radiation, and the potential for long-term cell monitoring. Three decades of innovation in both contrast agent chemistry and imaging physics have built an expansive array of probes and methods to track cells non-invasively across a diverse range of applications. In this review, we describe both established and emerging MRI cell tracking approaches and the variety of mechanisms available for contrast generation. Emphasis is given to the advantages, practical limitations, and persistent challenges of each approach, incorporating quantitative comparisons where possible. Toward the end of this review, we take a deeper dive into three key application areas - tracking cancer metastasis, immunotherapy for cancer, and stem cell regeneration - and discuss the cell tracking techniques most suitable to each.
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Affiliation(s)
- Hai-Ling Margaret Cheng
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada
- Ted Rogers Centre for Heart Research, Translational Biology & Engineering Program, Toronto, ON, Canada
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11
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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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12
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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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13
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Zheng N, Li M, Wu Y, Kaewborisuth C, Li Z, Gui Z, Wu J, Cai A, Lin K, Su KP, Xiang H, Tian X, Manyande A, Xu F, Wang J. A novel technology for in vivo detection of cell type-specific neural connection with AQP1-encoding rAAV2-retro vector and metal-free MRI. Neuroimage 2022; 258:119402. [PMID: 35732245 DOI: 10.1016/j.neuroimage.2022.119402] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 06/18/2022] [Accepted: 06/18/2022] [Indexed: 01/10/2023] Open
Abstract
A mammalian brain contains numerous neurons with distinct cell types for complex neural circuits. Virus-based circuit tracing tools are powerful in tracking the interaction among the different brain regions. However, detecting brain-wide neural networks in vivo remains challenging since most viral tracing systems rely on postmortem optical imaging. We developed a novel approach that enables in vivo detection of brain-wide neural connections based on metal-free magnetic resonance imaging (MRI). The recombinant adeno-associated virus (rAAV) with retrograde ability, the rAAV2-retro, encoding the human water channel aquaporin 1 (AQP1) MRI reporter gene was generated to label neural connections. The mouse was micro-injected with the virus at the Caudate Putamen (CPU) region and subjected to detection with Diffusion-weighted MRI (DWI). The prominent structure of the CPU-connected network was clearly defined. In combination with a Cre-loxP system, rAAV2-retro expressing Cre-dependent AQP1 provides a CPU-connected network of specific type neurons. Here, we established a sensitive, metal-free MRI-based strategy for in vivo detection of cell type-specific neural connections in the whole brain, which could visualize the dynamic changes of neural networks in rodents and potentially in non-human primates.
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Affiliation(s)
- Ning Zheng
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Wuhan 430071, China
| | - Mei Li
- The Brain Cognition and Brain Disease Institute (BCBDI), NMPA Key Laboratory for Research and Evaluation of Viral Vector Technology in Cell and Gene Therapy Medicinal Products, Shenzhen Key Laboratory of Viral Vectors for Biomedicine, Shenzhen Institute of Advanced Technology, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Yang Wu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Wuhan 430071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Challika Kaewborisuth
- Virology and Cell Technology Research Team, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani 12120, Thailand
| | - Zhen Li
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zhu Gui
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Wuhan 430071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinfeng Wu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Wuhan 430071, China
| | - Aoling Cai
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Wuhan 430071, China
| | - Kangguang Lin
- Department of Affective Disorders, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Kuan-Pin Su
- Department of Psychiatry, China Medical University Hospital, Taichung City, Taiwan, China
| | - Hongbing Xiang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xuebi Tian
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Anne Manyande
- School of Human and Social Sciences, University of West London, Middlesex, TW8 9GA, UK
| | - Fuqiang Xu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Wuhan 430071, China; The Brain Cognition and Brain Disease Institute (BCBDI), NMPA Key Laboratory for Research and Evaluation of Viral Vector Technology in Cell and Gene Therapy Medicinal Products, Shenzhen Key Laboratory of Viral Vectors for Biomedicine, Shenzhen Institute of Advanced Technology, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Chinese Academy of Sciences, Shenzhen 518055, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jie Wang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Wuhan 430071, China; Institute of Neuroscience and Brain Diseases, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei, China.
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14
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Uselman TW, Medina CS, Gray HB, Jacobs RE, Bearer EL. Longitudinal manganese-enhanced magnetic resonance imaging of neural projections and activity. NMR IN BIOMEDICINE 2022; 35:e4675. [PMID: 35253280 PMCID: PMC11064873 DOI: 10.1002/nbm.4675] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 10/19/2021] [Accepted: 12/07/2021] [Indexed: 06/14/2023]
Abstract
Manganese-enhanced magnetic resonance imaging (MEMRI) holds exceptional promise for preclinical studies of brain-wide physiology in awake-behaving animals. The objectives of this review are to update the current information regarding MEMRI and to inform new investigators as to its potential. Mn(II) is a powerful contrast agent for two main reasons: (1) high signal intensity at low doses; and (2) biological interactions, such as projection tracing and neural activity mapping via entry into electrically active neurons in the living brain. High-spin Mn(II) reduces the relaxation time of water protons: at Mn(II) concentrations typically encountered in MEMRI, robust hyperintensity is obtained without adverse effects. By selectively entering neurons through voltage-gated calcium channels, Mn(II) highlights active neurons. Safe doses may be repeated over weeks to allow for longitudinal imaging of brain-wide dynamics in the same individual across time. When delivered by stereotactic intracerebral injection, Mn(II) enters active neurons at the injection site and then travels inside axons for long distances, tracing neuronal projection anatomy. Rates of axonal transport within the brain were measured for the first time in "time-lapse" MEMRI. When delivered systemically, Mn(II) enters active neurons throughout the brain via voltage-sensitive calcium channels and clears slowly. Thus behavior can be monitored during Mn(II) uptake and hyperintense signals due to Mn(II) uptake captured retrospectively, allowing pairing of behavior with neural activity maps for the first time. Here we review critical information gained from MEMRI projection mapping about human neuropsychological disorders. We then discuss results from neural activity mapping from systemic Mn(II) imaged longitudinally that have illuminated development of the tonotopic map in the inferior colliculus as well as brain-wide responses to acute threat and how it evolves over time. MEMRI posed specific challenges for image data analysis that have recently been transcended. We predict a bright future for longitudinal MEMRI in pursuit of solutions to the brain-behavior mystery.
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Affiliation(s)
- Taylor W. Uselman
- University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | | | - Harry B. Gray
- Beckman Institute, California Institute of Technology, Pasadena, California, USA
| | - Russell E. Jacobs
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Elaine L. Bearer
- University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
- Beckman Institute, California Institute of Technology, Pasadena, California, USA
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15
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Tracking Neural Stem Cells in vivo: Achievements and Limitations. Stem Cell Rev Rep 2022; 18:1774-1788. [PMID: 35122628 DOI: 10.1007/s12015-022-10333-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2022] [Indexed: 12/12/2022]
Abstract
Neural stem cell (NSC) therapies are developing rapidly and have been proposed as a treatment option for various neurological diseases, such as stroke, Parkinson's disease and multiple sclerosis. However, monitoring transplanted NSCs, exploring their location and migration, and evaluating their efficacy and safety have all become serious and important issues. Two main problems in tracking NSCs have been noted: labeling them for visibility and imaging them. Direct labeling and reporter gene labeling are the two main methods for labeling stem cells. Magnetic resonance imaging and nuclear imaging, including positron emission tomography, single-photon emission computed tomography, and optical imaging, are the most commonly used imaging techniques. Each has its strengths and weaknesses. Thus, multimodal imaging, which combines two or more imaging methods to complement the advantages and disadvantages of each, has garnered increased attention. Advances in image fusion and nanotechnology, as well as the exploration of new tracers and new imaging modalities have substantially facilitated the development of NSC tracking technology. However, the safety issues related to tracking and long-term tracking of cell viability are still challenges. In this review, we discuss the merits and defects of different labeling and imaging methods, as well as recent advances, challenges and prospects in NSC tracking.
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16
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Computationally designed dual-color MRI reporters for noninvasive imaging of transgene expression. Nat Biotechnol 2022; 40:1143-1149. [PMID: 35102291 DOI: 10.1038/s41587-021-01162-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 11/12/2021] [Indexed: 12/13/2022]
Abstract
Imaging of gene-expression patterns in live animals is difficult to achieve with fluorescent proteins because tissues are opaque to visible light. Imaging of transgene expression with magnetic resonance imaging (MRI), which penetrates to deep tissues, has been limited by single reporter visualization capabilities. Moreover, the low-throughput capacity of MRI limits large-scale mutagenesis strategies to improve existing reporters. Here we develop an MRI system, called GeneREFORM, comprising orthogonal reporters for two-color imaging of transgene expression in deep tissues. Starting from two promiscuous deoxyribonucleoside kinases, we computationally designed highly active, orthogonal enzymes ('reporter genes') that specifically phosphorylate two MRI-detectable synthetic deoxyribonucleosides ('reporter probes'). Systemically administered reporter probes exclusively accumulate in cells expressing the designed reporter genes, and their distribution is displayed as pseudo-colored MRI maps based on dynamic proton exchange for noninvasive visualization of transgene expression. We envision that future extensions of GeneREFORM will pave the way to multiplexed deep-tissue mapping of gene expression in live animals.
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17
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Ozbakir HF, Miller ADC, Fishman KB, Martins AF, Kippin TE, Mukherjee A. A Protein-Based Biosensor for Detecting Calcium by Magnetic Resonance Imaging. ACS Sens 2021; 6:3163-3169. [PMID: 34420291 DOI: 10.1021/acssensors.1c01085] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Calcium-responsive contrast agents for magnetic resonance imaging (MRI) offer a promising approach for noninvasive brain-wide monitoring of neural activity at any arbitrary depth. Current examples of MRI-based calcium probes involve synthetic molecules and nanoparticles, which cannot be used to examine calcium signaling in a genetically encoded form. Here, we describe a new MRI sensor for calcium, based entirely on a naturally occurring calcium-binding protein known as calprotectin. Calcium-binding causes calprotectin to sequester manganese ions, thereby limiting Mn2+ enhanced paramagnetic relaxation of nearby water molecules. We demonstrate that this mechanism allows calprotectin to alter T1 and T2 based MRI signals in response to biologically relevant calcium concentrations. The resulting response amplitude, i.e., change in relaxation time, is comparable to existing MRI-based calcium sensors as well as other reported protein-based MRI sensors. As a preliminary demonstration of its biological applicability, we used calprotectin to detect calcium in a lysed hippocampal cell preparation as well as in intact Chinese hamster ovary cells treated with a calcium ionophore. Calprotectin thus represents a promising path toward noninvasive imaging of calcium signaling by combining the molecular and cellular specificity of genetically encodable tools with the ability of MRI to image through scattering tissue of any size and depth.
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18
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Petrus E, Saar G, Daoust A, Dodd S, Koretsky AP. A hierarchy of manganese competition and entry in organotypic hippocampal slice cultures. NMR IN BIOMEDICINE 2021; 34:e4476. [PMID: 33538073 PMCID: PMC7988546 DOI: 10.1002/nbm.4476] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 01/02/2021] [Indexed: 05/15/2023]
Abstract
Contrast agents improve clinical and basic research MRI. The manganese ion (Mn2+ ) is an essential, endogenous metal found in cells and it enhances MRI contrast because of its paramagnetic properties. Manganese-enhanced MRI (MEMRI) has been widely used to image healthy and diseased states of the body and the brain in a variety of animal models. There has also been some work in translating the useful properties of MEMRI to humans. Mn2+ accumulates in brain regions with high neural activity and enters cells via voltage-dependent channels that flux calcium (Ca2+ ). In addition, metal transporters for zinc (Zn2+ ) and iron (Fe2+ ) can also transport Mn2+ . There is also transfer through channels specific for Mn2+ . Although Mn2+ accumulates in many tissues including brain, the mechanisms and preferences of its mode of entry into cells are not well characterized. The current study used MRI on living organotypic hippocampal slice cultures to detect which transport mechanisms are preferentially used by Mn2+ to enter cells. The use of slice culture overcomes the presence of the blood brain barrier, which limits inferences made with studies of the intact brain in vivo. A range of Mn2+ concentrations were used and their effects on neural activity were assessed to avoid using interfering doses of Mn2+ . Zn2+ and Fe2+ were the most efficient competitors for Mn2+ uptake into the cultured slices, while the presence of Ca2+ or Ca2+ channel antagonists had a more moderate effect. Reducing slice activity via excitatory receptor antagonists was also effective at lowering Mn2+ uptake. In conclusion, a hierarchy of those agents which influence Mn2+ uptake was established to enhance understanding of how Mn2+ enters cells in a cultured slice preparation.
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Affiliation(s)
- Emily Petrus
- Laboratory of Functional and Molecular ImagingNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMarylandUSA
| | - Galit Saar
- Laboratory of Functional and Molecular ImagingNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMarylandUSA
| | - Alexia Daoust
- Laboratory of Functional and Molecular ImagingNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMarylandUSA
| | - Steve Dodd
- Laboratory of Functional and Molecular ImagingNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMarylandUSA
| | - Alan P. Koretsky
- Laboratory of Functional and Molecular ImagingNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMarylandUSA
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19
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Szulc DA, Lee XA, Cheng HYM, Cheng HLM. Bright Ferritin-a Reporter Gene Platform for On-Demand, Longitudinal Cell Tracking on MRI. iScience 2020; 23:101350. [PMID: 32707432 PMCID: PMC7381694 DOI: 10.1016/j.isci.2020.101350] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/14/2020] [Accepted: 07/03/2020] [Indexed: 02/02/2023] Open
Abstract
A major unresolved challenge in cell-based regenerative medicine is the absence of non-invasive technologies for tracking cell fate in deep tissue and with high spatial resolution over an extended interval. MRI is highly suited for this task, but current methods fail to provide longitudinal monitoring or high sensitivity, or both. In this study, we fill this technological gap with the first discovery and demonstration of in vivo cellular production of endogenous bright contrast via an MRI genetic reporter system that forms manganese-ferritin nanoparticles. We demonstrate this technology in human embryonic kidney cells genetically modified to stably overexpress ferritin and show that, in the presence of manganese, these cells produce far greater contrast than conventional ferritin overexpression with iron or manganese-permeable cells. In living mice, diffusely implanted bright-ferritin cells produce the highest and most sustained contrast in skeletal muscle. The bright-ferritin platform has potential for on-demand, longitudinal, and sensitive cell tracking in vivo.
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Affiliation(s)
- Daniel A Szulc
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, RS407, Toronto, ON M5S 3G9, Canada; Ted Rogers Centre for Heart Research, Translational Biology & Engineering Program, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Xavier A Lee
- Ted Rogers Centre for Heart Research, Translational Biology & Engineering Program, University of Toronto, Toronto, ON M5G 1M1, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Hai-Ying Mary Cheng
- Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Hai-Ling Margaret Cheng
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, RS407, Toronto, ON M5S 3G9, Canada; Ted Rogers Centre for Heart Research, Translational Biology & Engineering Program, University of Toronto, Toronto, ON M5G 1M1, Canada; The Edward S. Rogers Sr. Department of Electrical & Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada.
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20
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Ozbakir HF, Anderson NT, Fan KC, Mukherjee A. Beyond the Green Fluorescent Protein: Biomolecular Reporters for Anaerobic and Deep-Tissue Imaging. Bioconjug Chem 2020; 31:293-302. [PMID: 31794658 PMCID: PMC7033020 DOI: 10.1021/acs.bioconjchem.9b00688] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Fluorescence imaging represents cornerstone technology for studying biological function at the cellular and molecular levels. The technology's centerpiece is a prolific collection of genetic reporters based on the green fluorescent protein (GFP) and related analogs. More than two decades of protein engineering have endowed the GFP repertoire with an incredible assortment of fluorescent proteins, allowing scientists immense latitude in choosing reporters tailored to various cellular and environmental contexts. Nevertheless, GFP and derivative reporters have specific limitations that hinder their unrestricted use for molecular imaging. These challenges have inspired the development of new reporter proteins and imaging mechanisms. Here, we review how these developments are expanding the frontiers of reporter gene techniques to enable nondestructive studies of cell function in anaerobic environments and deep inside intact animals-two important biological contexts that are fundamentally incompatible with the use of GFP-based reporters.
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Affiliation(s)
- Harun F. Ozbakir
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Nolan T. Anderson
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Kang-Ching Fan
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Arnab Mukherjee
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
- Department of Chemistry, University of California, Santa Barbara, California 93106, United States
- Neuroscience Research Institute, University of California, Santa Barbara, California 93106, United States
- Center for Bioengineering, University of California, Santa Barbara, California 93106, United States
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21
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Rallapalli H, Tan IL, Volkova E, Wojcinski A, Darwin BC, Lerch JP, Joyner AL, Turnbull DH. MEMRI-based imaging pipeline for guiding preclinical studies in mouse models of sporadic medulloblastoma. Magn Reson Med 2020; 83:214-227. [PMID: 31403226 PMCID: PMC6778701 DOI: 10.1002/mrm.27904] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 06/20/2019] [Accepted: 06/24/2019] [Indexed: 01/07/2023]
Abstract
PURPOSE Genetically engineered mouse models of sporadic cancers are critical for studying tumor biology and for preclinical testing of therapeutics. We present an MRI-based pipeline designed to produce high resolution, quantitative information about tumor progression and response to novel therapies in mouse models of medulloblastoma (MB). METHODS Sporadic MB was modeled in mice by inducing expression of an activated form of the Smoothened gene (aSmo) in a small number of cerebellar granule cell precursors. aSmo mice were imaged and analyzed at defined time-points using a 3D manganese-enhanced MRI-based pipeline optimized for high-throughput. RESULTS A semi-automated segmentation protocol was established that estimates tumor volume in a time-frame compatible with a high-throughput pipeline. Both an empirical, volume-based classifier and a linear discriminant analysis-based classifier were tested to distinguish progressing from nonprogressing lesions at early stages of tumorigenesis. Tumor centroids measured at early stages revealed that there is a very specific location of the probable origin of the aSmo MB tumors. The efficacy of the manganese-enhanced MRI pipeline was demonstrated with a small-scale experimental drug trial designed to reduce the number of tumor associated macrophages and microglia. CONCLUSION Our results revealed a high level of heterogeneity between tumors within and between aSmo MB models, indicating that meaningful studies of sporadic tumor progression and response to therapy could not be conducted without an imaging-based pipeline approach.
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Affiliation(s)
- Harikrishna Rallapalli
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine
- Department of Radiology, New York University School of Medicine
- Biomedical Imaging Graduate Program, New York University School of Medicine
| | - I-Li Tan
- Developmental Biology Program, Sloan Kettering Institute
- Biochemistry, Cell and Molecular Biology Program, Weill Graduate School of Medical Sciences of Cornell University
| | - Eugenia Volkova
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine
| | | | - Benjamin C. Darwin
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jason P. Lerch
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Alexandra L. Joyner
- Developmental Biology Program, Sloan Kettering Institute
- Biochemistry, Cell and Molecular Biology Program, Weill Graduate School of Medical Sciences of Cornell University
| | - Daniel H. Turnbull
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine
- Department of Radiology, New York University School of Medicine
- Biomedical Imaging Graduate Program, New York University School of Medicine
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22
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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: 843] [Impact Index Per Article: 168.6] [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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23
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Cloyd RA, Koren SA, Abisambra JF. Manganese-Enhanced Magnetic Resonance Imaging: Overview and Central Nervous System Applications With a Focus on Neurodegeneration. Front Aging Neurosci 2018; 10:403. [PMID: 30618710 PMCID: PMC6300587 DOI: 10.3389/fnagi.2018.00403] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 11/23/2018] [Indexed: 12/16/2022] Open
Abstract
Manganese-enhanced magnetic resonance imaging (MEMRI) rose to prominence in the 1990s as a sensitive approach to high contrast imaging. Following the discovery of manganese conductance through calcium-permeable channels, MEMRI applications expanded to include functional imaging in the central nervous system (CNS) and other body systems. MEMRI has since been employed in the investigation of physiology in many animal models and in humans. Here, we review historical perspectives that follow the evolution of applied MRI research into MEMRI with particular focus on its potential toxicity. Furthermore, we discuss the more current in vivo investigative uses of MEMRI in CNS investigations and the brief but decorated clinical usage of chelated manganese compound mangafodipir in humans.
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Affiliation(s)
- Ryan A Cloyd
- Department of Physiology, University of Kentucky, Lexington, KY, United States.,College of Medicine, University of Kentucky, Lexington, KY, United States.,Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
| | - Shon A Koren
- Department of Physiology, University of Kentucky, Lexington, KY, United States.,Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States.,Department of Neuroscience & Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, United States
| | - Jose F Abisambra
- Department of Physiology, University of Kentucky, Lexington, KY, United States.,Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States.,Department of Neuroscience & Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, United States.,Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, United States
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24
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Bose RJC, Mattrey RF. Accomplishments and challenges in stem cell imaging in vivo. Drug Discov Today 2018; 24:492-504. [PMID: 30342245 DOI: 10.1016/j.drudis.2018.10.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 09/24/2018] [Accepted: 10/13/2018] [Indexed: 02/08/2023]
Abstract
Stem cell therapies have demonstrated promising preclinical results, but very few applications have reached the clinic owing to safety and efficacy concerns. Translation would benefit greatly if stem cell survival, distribution and function could be assessed in vivo post-transplantation, particularly in patients. Advances in molecular imaging have led to extraordinary progress, with several strategies being deployed to understand the fate of stem cells in vivo using magnetic resonance, scintigraphy, PET, ultrasound and optical imaging. Here, we review the recent advances, challenges and future perspectives and opportunities in stem cell tracking and functional assessment, as well as the advantages and challenges of each imaging approach.
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Affiliation(s)
- Rajendran J C Bose
- Department of Radiology and Advanced Imaging Research Center, 5323 Harry Hines Blvd, UT Southwestern Medical Center, Dallas, TX 75390-8514, USA; Current affiliation: Molecular Imaging Program at Stanford (MIPS) and the Canary Center at Stanford for Cancer Early Detection, Department of Radiology, School of Medicine, Stanford University, Stanford, CA 94305-5427, USA
| | - Robert F Mattrey
- Department of Radiology and Advanced Imaging Research Center, 5323 Harry Hines Blvd, UT Southwestern Medical Center, Dallas, TX 75390-8514, USA.
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Ghosh S, Harvey P, Simon JC, Jasanoff A. Probing the brain with molecular fMRI. Curr Opin Neurobiol 2018; 50:201-210. [PMID: 29649765 DOI: 10.1016/j.conb.2018.03.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 02/12/2018] [Accepted: 03/21/2018] [Indexed: 01/07/2023]
Abstract
One of the greatest challenges of modern neuroscience is to incorporate our growing knowledge of molecular and cellular-scale physiology into integrated, organismic-scale models of brain function in behavior and cognition. Molecular-level functional magnetic resonance imaging (molecular fMRI) is a new technology that can help bridge these scales by mapping defined microscopic phenomena over large, optically inaccessible regions of the living brain. In this review, we explain how MRI-detectable imaging probes can be used to sensitize noninvasive imaging to mechanistically significant components of neural processing. We discuss how a combination of innovative probe design, advanced imaging methods, and strategies for brain delivery can make molecular fMRI an increasingly successful approach for spatiotemporally resolved studies of diverse neural phenomena, perhaps eventually in people.
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Affiliation(s)
- Souparno Ghosh
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Rm. 16-561, Cambridge, MA 02139, United States
| | - Peter Harvey
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Rm. 16-561, Cambridge, MA 02139, United States
| | - Jacob C Simon
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Rm. 16-561, Cambridge, MA 02139, United States
| | - Alan Jasanoff
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Rm. 16-561, Cambridge, MA 02139, United States; Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, 77 Massachusetts Ave., Rm. 16-561, Cambridge, MA 02139, United States; Department of Nuclear Science & Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Rm. 16-561, Cambridge, MA 02139, United States.
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26
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Bedenk BT, Almeida-Corrêa S, Jurik A, Dedic N, Grünecker B, Genewsky AJ, Kaltwasser SF, Riebe CJ, Deussing JM, Czisch M, Wotjak CT. Mn 2+ dynamics in manganese-enhanced MRI (MEMRI): Ca v1.2 channel-mediated uptake and preferential accumulation in projection terminals. Neuroimage 2017; 169:374-382. [PMID: 29277401 DOI: 10.1016/j.neuroimage.2017.12.054] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 11/27/2017] [Accepted: 12/18/2017] [Indexed: 12/11/2022] Open
Abstract
Manganese-enhanced magnetic resonance imaging (MEMRI) exploits the biophysical similarity of Ca2+ and Mn2+ to map the brain's activity in vivo. However, to what extent different Ca2+ channels contribute to the enhanced signal that MEMRI provides and how Mn2+ dynamics influence Mn2+ brain accumulation after systemic administration of MnCl2 are not yet fully understood. Here, we demonstrate that mice lacking the L-type Ca2+ channel 1.2 (Cav1.2) in the CNS show approximately 50% less increase in MEMRI contrast after repeated systemic MnCl2 injections, as compared to control mice. In contrast, genetic deletion of L-type Ca2+ channel 1.3 (Cav1.3) did not reduce signal. Brain structure- or cell type-specific deletion of Cav1.2 in combination with voxel-wise MEMRI analysis revealed a preferential accumulation of Mn2+ in projection terminals, which was confirmed by local MnCl2 administration to defined brain areas. Taken together, we provide unequivocal evidence that Cav1.2 represents an important channel for neuronal Mn2+ influx after systemic injections. We also show that after neuronal uptake, Mn2+ preferentially accumulates in projection terminals.
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Affiliation(s)
- Benedikt T Bedenk
- Max Planck Institute of Psychiatry, Dept. Stress Neurobiology & Neurogenetics, Kraepelinstr. 2-10, 80804 Munich, Germany; Max Planck Institute of Psychiatry, Core Unit Neuroimaging, Kraepelinstr. 2-10, 80804 Munich, Germany
| | - Suellen Almeida-Corrêa
- Max Planck Institute of Psychiatry, Dept. Stress Neurobiology & Neurogenetics, Kraepelinstr. 2-10, 80804 Munich, Germany
| | - Angela Jurik
- Max Planck Institute of Psychiatry, Dept. Stress Neurobiology & Neurogenetics, Kraepelinstr. 2-10, 80804 Munich, Germany
| | - Nina Dedic
- Max Planck Institute of Psychiatry, Dept. Stress Neurobiology & Neurogenetics, Kraepelinstr. 2-10, 80804 Munich, Germany
| | - Barbara Grünecker
- Max Planck Institute of Psychiatry, Core Unit Neuroimaging, Kraepelinstr. 2-10, 80804 Munich, Germany
| | - Andreas J Genewsky
- Max Planck Institute of Psychiatry, Dept. Stress Neurobiology & Neurogenetics, Kraepelinstr. 2-10, 80804 Munich, Germany
| | - Sebastian F Kaltwasser
- Max Planck Institute of Psychiatry, Dept. Stress Neurobiology & Neurogenetics, Kraepelinstr. 2-10, 80804 Munich, Germany
| | - Caitlin J Riebe
- Max Planck Institute of Psychiatry, Dept. Stress Neurobiology & Neurogenetics, Kraepelinstr. 2-10, 80804 Munich, Germany
| | - Jan M Deussing
- Max Planck Institute of Psychiatry, Dept. Stress Neurobiology & Neurogenetics, Kraepelinstr. 2-10, 80804 Munich, Germany
| | - Michael Czisch
- Max Planck Institute of Psychiatry, Core Unit Neuroimaging, Kraepelinstr. 2-10, 80804 Munich, Germany
| | - Carsten T Wotjak
- Max Planck Institute of Psychiatry, Dept. Stress Neurobiology & Neurogenetics, Kraepelinstr. 2-10, 80804 Munich, Germany.
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27
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Svehla P, Bédécarrats A, Jahn C, Nargeot R, Ciobanu L. Intracellular manganese enhanced MRI signals reflect the frequency of action potentials in Aplysia neurons. J Neurosci Methods 2017; 295:121-128. [PMID: 29248445 DOI: 10.1016/j.jneumeth.2017.12.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 12/12/2017] [Accepted: 12/13/2017] [Indexed: 01/05/2023]
Abstract
BACKGROUND Manganese-enhanced magnetic resonance imaging (MEMRI) is an increasingly popular alternative to standard functional MRI methods in animal studies. The contrast in MEMRI images is based on the accumulation of Mn2+ ions inside neurons, and, since manganese can serve as calcium analogue, this accumulation reflects calcium dynamics providing versatile information about brain neuroarchitecture and functionality. However, despite its use as a functional imaging tool, the exact relationship between the MEMRI signal and neuronal activity remains elusive. NEW METHOD In order to better understand the mechanisms underlying Mn2+ accumulation resulting in MEMRI signal enhancement we investigated single neuron responses of isolated Aplysia buccal ganglia subjected to chemical (dopamine) or electrical stimulation of an input nerve (oesophageal nerve). The elicited electrical activity that represents a fictive feeding was recorded with electrophysiological methods and the Mn2+ uptake in individual neurons was evaluated with MEMRI at 17.2T. RESULTS & COMPARISON WITH EXISTING METHOD(S) We show a positive correlation between bursts of electrical activity and MEMRI signal intensity in identified neurons and demonstrate that the MEMRI signal reflects mainly fast and high membrane depolarization processes such as action potentials, and it is not sensitive to slow and small membrane depolarizations, such as post-synaptic potentials.
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Affiliation(s)
- Pavel Svehla
- NeuroSpin, CEA Saclay, 91191 Gif-sur-Yvette, France; University Paris-Sud, XI, 91450 Orsay, France
| | | | | | - Romuald Nargeot
- University of Bordeaux, INCIA, UMR 5287, F-33000 Bordeaux, France
| | - Luisa Ciobanu
- NeuroSpin, CEA Saclay, 91191 Gif-sur-Yvette, France.
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28
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Alvares RDA, Szulc DA, Cheng HLM. A scale to measure MRI contrast agent sensitivity. Sci Rep 2017; 7:15493. [PMID: 29138455 PMCID: PMC5686147 DOI: 10.1038/s41598-017-15732-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 11/01/2017] [Indexed: 01/17/2023] Open
Abstract
Magnetic resonance imaging (MRI) provides superior resolution of anatomical features and the best soft tissue contrast, and is one of the predominant imaging modalities. With this technique, contrast agents are often used to aid discrimination by enhancing specific features. Over the years, a rich diversity of such agents has evolved and with that, so has a need to systematically sort contrast agents based on their efficiency, which directly determines sensitivity. Herein, we present a scale to rank MRI contrast agents. The scale is based on analytically determining the minimum detectable concentration of a contrast agent, and employing a ratiometric approach to standardize contrast efficiency to a benchmark contrast agent. We demonstrate the approach using several model contrast agents and compare the relative sensitivity of these agents for the first time. As the first universal metric of contrast agent sensitivity, this scale will be vital to easily assessing contrast agent efficiency and thus important to promoting use of some of the elegant and diverse contrast agents in research and clinical practice.
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Affiliation(s)
- Rohan D A Alvares
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada
| | - Daniel A Szulc
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada
| | - Hai-Ling M Cheng
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.
- Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Ontario, Canada.
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada.
- Ontario Institute for Regenerative Medicine, Toronto, Ontario, Canada.
- Heart & Stroke/Richard Lewar Centre of Excellence for Cardiovascular Research, Toronto, Ontario, Canada.
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29
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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: 29] [Impact Index Per Article: 4.1] [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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30
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Genetically encoded iron-associated proteins as MRI reporters for molecular and cellular imaging. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2017; 10. [DOI: 10.1002/wnan.1482] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 04/18/2017] [Accepted: 05/04/2017] [Indexed: 02/06/2023]
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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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32
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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: 65] [Impact Index Per Article: 8.1] [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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33
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Vistain LF, Rotz MW, Rathore R, Preslar AT, Meade TJ. Targeted delivery of gold nanoparticle contrast agents for reporting gene detection by magnetic resonance imaging. Chem Commun (Camb) 2016; 52:160-3. [PMID: 26505558 DOI: 10.1039/c5cc06565h] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Detection of protein expression by MRI requires a high payload of Gd(III) per protein binding event. Presented here is a targeted AuDNA nanoparticle capable of delivering several hundred Gd(III) chelates to the HaloTag reporter protein. Incubating this particle with HaloTag-expressing cells produced a 9.4 contrast-to-noise ratio compared to non-expressing cells.
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Affiliation(s)
- Luke F Vistain
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA.
| | - Matthew W Rotz
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA.
| | - Richa Rathore
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA.
| | - Adam T Preslar
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA.
| | - Thomas J Meade
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113, USA.
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Cho IK, Wang S, Mao H, Chan AWS. Genetic engineered molecular imaging probes for applications in cell therapy: emphasis on MRI approach. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2016; 6:234-261. [PMID: 27766183 PMCID: PMC5069277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 08/31/2016] [Indexed: 06/06/2023]
Abstract
Recent advances in stem cell-based regenerative medicine, cell replacement therapy, and genome editing technologies (i.e. CRISPR-Cas 9) have sparked great interest in in vivo cell monitoring. Molecular imaging promises a unique approach to noninvasively monitor cellular and molecular phenomena, including cell survival, migration, proliferation, and even differentiation at the whole organismal level. Several imaging modalities and strategies have been explored for monitoring cell grafts in vivo. We begin this review with an introduction describing the progress in stem cell technology, with a perspective toward cell replacement therapy. The importance of molecular imaging in reporting and assessing the status of cell grafts and their relation to the local microenvironment is highlighted since the current knowledge gap is one of the major obstacles in clinical translation of stem cell therapy. Based on currently available imaging techniques, we provide a brief discussion on the pros and cons of each imaging modality used for monitoring cell grafts with particular emphasis on magnetic resonance imaging (MRI) and the reporter gene approach. Finally, we conclude with a comprehensive discussion of future directions of applying molecular imaging in regenerative medicine to emphasize further the importance of correlating cell graft conditions and clinical outcomes to advance regenerative medicine.
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Affiliation(s)
- In K Cho
- Department of Human Genetics, Emory University School of MedicineAtlanta, GA, USA
- Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research CenterAtlanta, GA, USA
| | - Silun Wang
- Department of Radiology and Imaging Sciences, Emory University School of MedicineAtlanta, GA, USA
| | - Hui Mao
- Department of Radiology and Imaging Sciences, Emory University School of MedicineAtlanta, GA, USA
| | - Anthony WS Chan
- Department of Human Genetics, Emory University School of MedicineAtlanta, GA, USA
- Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research CenterAtlanta, GA, USA
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Abstract
UNLABELLED Comprehensive analysis of brain function depends on understanding the dynamics of diverse neural signaling processes over large tissue volumes in intact animals and humans. Most existing approaches to measuring brain signaling suffer from limited tissue penetration, poor resolution, or lack of specificity for well-defined neural events. Here we discuss a new brain activity mapping method that overcomes some of these problems by combining MRI with contrast agents sensitive to neural signaling. The goal of this "molecular fMRI" approach is to permit noninvasive whole-brain neuroimaging with specificity and resolution approaching current optical neuroimaging methods. In this article, we describe the context and need for molecular fMRI as well as the state of the technology today. We explain how major types of MRI probes work and how they can be sensitized to neurobiological processes, such as neurotransmitter release, calcium signaling, and gene expression changes. We comment both on past work in the field and on challenges and promising avenues for future development. SIGNIFICANCE STATEMENT Brain researchers currently have a choice between measuring neural activity using cellular-level recording techniques, such as electrophysiology and optical imaging, or whole-brain imaging methods, such as fMRI. Cellular level methods are precise but only address a small portion of mammalian brains; on the other hand, whole-brain neuroimaging techniques provide very little specificity for neural pathways or signaling components of interest. The molecular fMRI techniques we discuss have particular potential to combine the specificity of cellular-level measurements with the noninvasive whole-brain coverage of fMRI. On the other hand, molecular fMRI is only just getting off the ground. This article aims to offer a snapshot of the status and future prospects for development of molecular fMRI techniques.
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Kraidith K, Svasti S, Teerapornpuntakit J, Vadolas J, Chaimana R, Lapmanee S, Suntornsaratoon P, Krishnamra N, Fucharoen S, Charoenphandhu N. Hepcidin and 1,25(OH)2D3 effectively restore Ca2+ transport in β-thalassemic mice: reciprocal phenomenon of Fe2+ and Ca2+ absorption. Am J Physiol Endocrinol Metab 2016; 311:E214-23. [PMID: 27245334 DOI: 10.1152/ajpendo.00067.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 05/23/2016] [Indexed: 12/15/2022]
Abstract
Previously, β-thalassemia, an inherited anemic disorder with iron overload caused by loss-of-function mutation of β-globin gene, has been reported to induce osteopenia and impaired whole body calcium metabolism, but the pathogenesis of aberrant calcium homeostasis remains elusive. Herein, we investigated how β-thalassemia impaired intestinal calcium absorption and whether it could be restored by administration of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] or hepcidin, the latter of which was the liver-derived antagonist of intestinal iron absorption. The results showed that, in hemizygous β-globin knockout (BKO) mice, the duodenal calcium transport was lower than that in wild-type littermates, and severity was especially pronounced in female mice. Both active and passive duodenal calcium fluxes in BKO mice were found to be less than those in normal mice. This impaired calcium transport could be restored by 7-day 1,25(OH)2D3 treatment. The 1,25(OH)2D3-induced calcium transport was diminished by inhibitors of calcium transporters, e.g., L-type calcium channel, NCX1, and PMCA1b, as well as vesicular transport inhibitors. Interestingly, the duodenal calcium transport exhibited an inverse correlation with transepithelial iron transport, which was markedly enhanced in thalassemic mice. Thus, 3-day subcutaneous hepcidin injection and acute direct hepcidin exposure in the Ussing chamber were capable of restoring the thalassemia-associated impairment of calcium transport; however, the positive effect of hepcidin on calcium transport was completely blocked by proteasome inhibitors MG132 and bortezomib. In conclusion, both 1,25(OH)2D3 and hepcidin could be used to alleviate the β-thalassemia-associated impairment of calcium absorption. Therefore, our study has shed light on the development of a treatment strategy to rescue calcium dysregulation in β-thalassemia.
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Affiliation(s)
- Kamonshanok Kraidith
- Center of Calcium and Bone Research, Faculty of Science, Mahidol University, Bangkok, Thailand; Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Saovaros Svasti
- Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand; and
| | | | - Jim Vadolas
- Cell and Gene Therapy Research Group, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Australia
| | - Rattana Chaimana
- Center of Calcium and Bone Research, Faculty of Science, Mahidol University, Bangkok, Thailand; Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Sarawut Lapmanee
- Center of Calcium and Bone Research, Faculty of Science, Mahidol University, Bangkok, Thailand; Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Panan Suntornsaratoon
- Center of Calcium and Bone Research, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Nateetip Krishnamra
- Center of Calcium and Bone Research, Faculty of Science, Mahidol University, Bangkok, Thailand; Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Suthat Fucharoen
- Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand; and
| | - Narattaphol Charoenphandhu
- Center of Calcium and Bone Research, Faculty of Science, Mahidol University, Bangkok, Thailand; Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand;
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Barandov A, Bartelle BB, Gonzalez BA, White WL, Lippard SJ, Jasanoff A. Membrane-Permeable Mn(III) Complexes for Molecular Magnetic Resonance Imaging of Intracellular Targets. J Am Chem Soc 2016; 138:5483-6. [PMID: 27088782 DOI: 10.1021/jacs.5b13337] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Intracellular compartments make up roughly two-thirds of the body, but delivery of molecular imaging probes to these spaces can be challenging. This situation is particularly true for probes designed for detection by magnetic resonance imaging (MRI), a high-resolution but relatively insensitive modality. Most MRI contrast agents are polar and membrane impermeant, making it difficult to deliver them in sufficient quantities for measurement of intracellular analytes. Here we address this problem by introducing a new class of planar tetradentate Mn(III) chelates assembled from a 1,2-phenylenediamido (PDA) backbone. Mn(III)-PDA complexes display T1 relaxivity comparable to that of Gd(III)-based contrast agents and undergo spontaneous cytosolic localization via defined mechanisms. Probe variants incorporating enzyme-cleavable acetomethoxy ester groups are processed by intracellular esterases and accumulate in cells. Probes modified with ethyl esters preferentially label genetically modified cells that express a substrate-selective esterase. In each case, the contrast agents gives rise to robust T1-weighted MRI enhancements, providing precedents for the detection of intracellular targets by Mn(III)-PDA complexes. These compounds therefore constitute a platform from which to develop reagents for molecular MRI of diverse processes inside cells.
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Affiliation(s)
- Ali Barandov
- Departments of †Biological Engineering, ‡Chemistry, §Brain and Cognitive Sciences, and ⊥Nuclear Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Benjamin B Bartelle
- Departments of †Biological Engineering, ‡Chemistry, §Brain and Cognitive Sciences, and ⊥Nuclear Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Beatriz A Gonzalez
- Departments of †Biological Engineering, ‡Chemistry, §Brain and Cognitive Sciences, and ⊥Nuclear Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - William L White
- Departments of †Biological Engineering, ‡Chemistry, §Brain and Cognitive Sciences, and ⊥Nuclear Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Stephen J Lippard
- Departments of †Biological Engineering, ‡Chemistry, §Brain and Cognitive Sciences, and ⊥Nuclear Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Alan Jasanoff
- Departments of †Biological Engineering, ‡Chemistry, §Brain and Cognitive Sciences, and ⊥Nuclear Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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Patrick PS, Rodrigues TB, Kettunen MI, Lyons SK, Neves AA, Brindle KM. Development of Timd2 as a reporter gene for MRI. Magn Reson Med 2016; 75:1697-707. [PMID: 25981669 PMCID: PMC4832381 DOI: 10.1002/mrm.25750] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 03/27/2015] [Accepted: 03/27/2015] [Indexed: 12/20/2022]
Abstract
PURPOSE To assess the potential of an MRI gene reporter based on the ferritin receptor Timd2 (T-cell immunoglobulin and mucin domain containing protein 2), using T1- and T2-weighted imaging. METHODS Pellets of cells that had been modified to express the Timd2 transgene, and incubated with either iron-loaded or manganese-loaded ferritin, were imaged using T1- and T2-weighted MRI. Mice were also implanted subcutaneously with Timd2-expressing cells and the resulting xenograft tissue imaged following intravenous injection of ferritin using T2-weighted imaging. RESULTS Timd2-expressing cells, but not control cells, showed a large increase in both R2 and R1 in vitro following incubation with iron-loaded and manganese-loaded ferritin, respectively. Expression of Timd2 had no effect on cell viability or proliferation; however, manganese-loaded ferritin, but not iron-loaded ferritin, was toxic to Timd2-expressing cells. Timd2-expressing xenografts in vivo showed much smaller changes in R2 following injection of iron-loaded ferritin than the same cells incubated in vitro with iron-loaded ferritin. CONCLUSION Timd2 has demonstrated potential as an MRI reporter gene, producing large increases in R2 and R1 with ferritin and manganese-loaded ferritin respectively in vitro, although more modest changes in R2 in vivo. Manganese-loaded apoferritin was not used in vivo due to the toxicity observed in vitro. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance.
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Affiliation(s)
- P. Stephen Patrick
- Department of BiochemistryUniversity of CambridgeCambridgeUnited Kingdom
- Cancer Research UK Cambridge Institute, University of CambridgeCambridgeUnited Kingdom
| | - Tiago B. Rodrigues
- Cancer Research UK Cambridge Institute, University of CambridgeCambridgeUnited Kingdom
| | - Mikko I. Kettunen
- Cancer Research UK Cambridge Institute, University of CambridgeCambridgeUnited Kingdom
| | - Scott K. Lyons
- Cancer Research UK Cambridge Institute, University of CambridgeCambridgeUnited Kingdom
| | - André A. Neves
- Cancer Research UK Cambridge Institute, University of CambridgeCambridgeUnited Kingdom
| | - Kevin M. Brindle
- Department of BiochemistryUniversity of CambridgeCambridgeUnited Kingdom
- Cancer Research UK Cambridge Institute, University of CambridgeCambridgeUnited Kingdom
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Increased Understanding of Stem Cell Behavior in Neurodegenerative and Neuromuscular Disorders by Use of Noninvasive Cell Imaging. Stem Cells Int 2016; 2016:6235687. [PMID: 26997958 PMCID: PMC4779824 DOI: 10.1155/2016/6235687] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 01/07/2016] [Accepted: 01/11/2016] [Indexed: 12/13/2022] Open
Abstract
Numerous neurodegenerative and neuromuscular disorders are associated with cell-specific depletion in the human body. This imbalance in tissue homeostasis is in healthy individuals repaired by the presence of endogenous stem cells that can replace the lost cell type. However, in most disorders, a genetic origin or limited presence or exhaustion of stem cells impairs correct cell replacement. During the last 30 years, methods to readily isolate and expand stem cells have been developed and this resulted in a major change in the regenerative medicine field as it generates sufficient amount of cells for human transplantation applications. Furthermore, stem cells have been shown to release cytokines with beneficial effects for several diseases. At present however, clinical stem cell transplantations studies are struggling to demonstrate clinical efficacy despite promising preclinical results. Therefore, to allow stem cell therapy to achieve its full potential, more insight in their in vivo behavior has to be achieved. Different methods to noninvasively monitor these cells have been developed and are discussed. In some cases, stem cell monitoring even reached the clinical setting. We anticipate that by further exploring these imaging possibilities and unraveling their in vivo behavior further improvement in stem cell transplantations will be achieved.
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Engineering intracellular biomineralization and biosensing by a magnetic protein. Nat Commun 2015; 6:8721. [PMID: 26522873 PMCID: PMC4667635 DOI: 10.1038/ncomms9721] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 09/24/2015] [Indexed: 11/08/2022] Open
Abstract
Remote measurement and manipulation of biological systems can be achieved using magnetic techniques, but a missing link is the availability of highly magnetic handles on cellular or molecular function. Here we address this need by using high-throughput genetic screening in yeast to select variants of the iron storage ferritin (Ft) that display enhanced iron accumulation under physiological conditions. Expression of Ft mutants selected from a library of 10(7) variants induces threefold greater cellular iron loading than mammalian heavy chain Ft, over fivefold higher contrast in magnetic resonance imaging, and robust retention on magnetic separation columns. Mechanistic studies of mutant Ft proteins indicate that improved magnetism arises in part from increased iron oxide nucleation efficiency. Molecular-level iron loading in engineered Ft enables detection of individual particles inside cells and facilitates creation of Ft-based intracellular magnetic devices. We demonstrate construction of a magnetic sensor actuated by gene expression in yeast.
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He X, Cai J, Liu B, Zhong Y, Qin Y. Cellular magnetic resonance imaging contrast generated by the ferritin heavy chain genetic reporter under the control of a Tet-On switch. Stem Cell Res Ther 2015; 6:207. [PMID: 26517988 PMCID: PMC4628232 DOI: 10.1186/s13287-015-0205-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 08/30/2015] [Accepted: 10/16/2015] [Indexed: 12/26/2022] Open
Abstract
INTRODUCTION Despite the strong appeal of ferritin as a magnetic resonance imaging (MRI) reporter for stem cell research, no attempts have been made to apply this genetic imaging reporter in stem cells in an inducible manner, which is important for minimizing the potential risk related to the constitutive expression of an imaging reporter. The aim of the present study was to develop an inducible genetic MRI reporter system that enables the production of intracellular MRI contrast as needed. METHODS Ferritin heavy chain (FTH1) was genetically modified by adding a Tet-On switch. A C3H10T1/2 cell line carrying Tet-FTH1 (C3H10T1/2-FTH1) was established via lentiviral transduction. The dose- and time-dependent expression of FTH1 in C3H10T1/2 cells was assessed by western blot and immunofluorescence staining. The induced "ON" and non-induced "OFF" expressions of FTH1 were detected using a 3.0 T MRI scanner. Iron accumulation in cells was analyzed by Prussian blue staining and transmission electron microscopy (TEM). RESULTS The expression of FTH1 was both dose- and time-dependently induced, and FTH1 expression peaked in response to induction with doxycycline (Dox) at 0.2 μg/ml for 72 h. The induced expression of FTH1 resulted in a significant increase in the transverse relaxation rate of C3H10T1/2-FTH1 cells following iron supplementation. Prussian blue staining and TEM revealed extensive iron accumulation in C3H10T1/2-FTH1 cells in the presence of Dox. CONCLUSIONS Cellular MRI contrast can be produced as needed via the expression of FTH1 under the control of a Tet-On switch. This finding could lay the groundwork for the use of FTH1 to track stem cells in vivo in an inducible manner.
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Affiliation(s)
- Xiaoya He
- Department of Radiology, Children's Hospital of Chongqing Medical University, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Ministry of Education Key Laboratory of Child Development and Disorders, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Key Laboratory of Pediatrics in Chongqing, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Chongqing International Science and Technology Cooperation Center For Child Development and Disorders, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China.
| | - Jinhua Cai
- Department of Radiology, Children's Hospital of Chongqing Medical University, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Ministry of Education Key Laboratory of Child Development and Disorders, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Key Laboratory of Pediatrics in Chongqing, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Chongqing International Science and Technology Cooperation Center For Child Development and Disorders, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China.
| | - Bo Liu
- Department of Radiology, Children's Hospital of Chongqing Medical University, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Ministry of Education Key Laboratory of Child Development and Disorders, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Key Laboratory of Pediatrics in Chongqing, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Chongqing International Science and Technology Cooperation Center For Child Development and Disorders, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China.
| | - Yi Zhong
- Department of Radiology, Children's Hospital of Chongqing Medical University, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Ministry of Education Key Laboratory of Child Development and Disorders, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Key Laboratory of Pediatrics in Chongqing, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Chongqing International Science and Technology Cooperation Center For Child Development and Disorders, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China.
| | - Yong Qin
- Department of Radiology, Children's Hospital of Chongqing Medical University, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Ministry of Education Key Laboratory of Child Development and Disorders, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Key Laboratory of Pediatrics in Chongqing, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China. .,Chongqing International Science and Technology Cooperation Center For Child Development and Disorders, 136 Zhongshan 2 Road, Yuzhong District, Chongqing, 400014, China.
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Lost signature: progress and failures in in vivo tracking of implanted stem cells. Appl Microbiol Biotechnol 2015; 99:9907-22. [DOI: 10.1007/s00253-015-6965-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 08/25/2015] [Accepted: 08/27/2015] [Indexed: 01/01/2023]
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Spatial memory training induces morphological changes detected by manganese-enhanced MRI in the hippocampal CA3 mossy fiber terminal zone. Neuroimage 2015; 128:227-237. [PMID: 26254115 DOI: 10.1016/j.neuroimage.2015.07.084] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 07/22/2015] [Accepted: 07/30/2015] [Indexed: 01/03/2023] Open
Abstract
Hippocampal mossy fibers (MFs) can show plasticity of their axon terminal arbor consequent to learning a spatial memory task. Such plasticity is seen as translaminar sprouting from the stratum lucidum (SL) of CA3 into the stratum pyramidale (SP) and the stratum oriens (SO). However, the functional role of this presynaptic remodeling is still obscure. In vivo imaging that allows longitudinal observation of such remodeling could provide a deeper understanding of this presynaptic growth phenomenon as it occurs over time. Here we used manganese-enhanced magnetic resonance imaging (MEMRI), which shows a high-contrast area that co-localizes with the MFs. This technique was applied in the detection of learning-induced MF plasticity in two strains of rats. Quantitative analysis of a series of sections in the rostral dorsal hippocampus showed increases in the CA3a' area in MEMRI of trained Wistar rats consistent with the increased SO+SP area seen in the Timm's staining. MF plasticity was not seen in the trained Lister-Hooded rats in either MEMRI or in Timm's staining. This indicates the potential of MEMRI for revealing neuro-architectures and plasticity of the hippocampal MF system in vivo in longitudinal studies.
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Bernau K, Lewis CM, Petelinsek AM, Reagan MS, Niles DJ, Mattis VB, Meyerand ME, Suzuki M, Svendsen CN. In Vivo Tracking of Human Neural Progenitor Cells in the Rat Brain Using Magnetic Resonance Imaging Is Not Enhanced by Ferritin Expression. Cell Transplant 2015; 25:575-92. [PMID: 26160767 DOI: 10.3727/096368915x688614] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Rapid growth in the field of stem cell research has generated a lot of interest in their therapeutic use, especially in the treatment of neurodegenerative diseases. Specifically, human neural progenitor cells (hNPCs), unique in their capability to differentiate into cells of the neural lineage, have been widely investigated due to their ability to survive, thrive, and migrate toward injured tissues. Still, one of the major roadblocks for clinical applicability arises from the inability to monitor these cells following transplantation. Molecular imaging techniques, such as magnetic resonance imaging (MRI), have been explored to assess hNPC transplant location, migration, and survival. Here we investigated whether inducing hNPCs to overexpress ferritin (hNPCs(Fer)), an iron storage protein, is sufficient to track these cells long term in the rat striatum using MRI. We found that increased hypointensity on MRI images could establish hNPC(Fer) location. Unexpectedly, however, wild-type hNPC transplants were detected in a similar manner, which is likely due to increased iron accumulation following transplantation-induced damage. Hence, we labeled hNPCs with superparamagnetic iron oxide (SPIO) nanoparticles to further increase iron content in an attempt to enhance cell contrast in MRI. SPIO-labeling of hNPCs (hNPCs-SPIO) achieved increased hypointensity, with significantly greater area of decreased T2* compared to hNPC(Fer) (p < 0.0001) and all other controls used. However, none of the techniques could be used to determine graft rejection in vivo, which is imperative for understanding cell behavior following transplantation. We conclude that in order for cell survival to be monitored in preclinical and clinical settings, another molecular imaging technique must be employed, including perhaps multimodal imaging, which would utilize MRI along with another imaging modality.
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Affiliation(s)
- Ksenija Bernau
- University of Wisconsin-Madison, Department of Biomedical Engineering, Madison, WI, USA
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Szulc KU, Lerch JP, Nieman BJ, Bartelle BB, Friedel M, Suero-Abreu GA, Watson C, Joyner AL, Turnbull DH. 4D MEMRI atlas of neonatal FVB/N mouse brain development. Neuroimage 2015; 118:49-62. [PMID: 26037053 DOI: 10.1016/j.neuroimage.2015.05.029] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 05/11/2015] [Accepted: 05/13/2015] [Indexed: 11/19/2022] Open
Abstract
The widespread use of the mouse as a model system to study brain development has created the need for noninvasive neuroimaging methods that can be applied to early postnatal mice. The goal of this study was to optimize in vivo three- (3D) and four-dimensional (4D) manganese (Mn)-enhanced MRI (MEMRI) approaches for acquiring and analyzing data from the developing mouse brain. The combination of custom, stage-dependent holders and self-gated (motion-correcting) 3D MRI sequences enabled the acquisition of high-resolution (100-μm isotropic), motion artifact-free brain images with a high level of contrast due to Mn-enhancement of numerous brain regions and nuclei. We acquired high-quality longitudinal brain images from two groups of FVB/N strain mice, six mice per group, each mouse imaged on alternate odd or even days (6 3D MEMRI images at each day) covering the developmental stages between postnatal days 1 to 11. The effects of Mn-exposure, anesthesia and MRI were assessed, showing small but significant transient effects on body weight and brain volume, which recovered with time and did not result in significant morphological differences when compared to controls. Metrics derived from deformation-based morphometry (DBM) were used for quantitative analysis of changes in volume and position of a number of brain regions. The cerebellum, a brain region undergoing significant changes in size and patterning at early postnatal stages, was analyzed in detail to demonstrate the spatiotemporal characterization made possible by this new atlas of mouse brain development. These results show that MEMRI is a powerful tool for quantitative analysis of mouse brain development, with great potential for in vivo phenotype analysis in mouse models of neurodevelopmental diseases.
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Affiliation(s)
- Kamila U Szulc
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA; Biomedical Imaging, New York University School of Medicine, New York, NY, USA
| | - Jason P Lerch
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Brian J Nieman
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada; Ontario Institute for Cancer Research, Toronto, ON, Canada
| | - Benjamin B Bartelle
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA; Molecular Biophysics Graduate Programs, New York University School of Medicine, New York, NY, USA
| | - Miriam Friedel
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, ON, Canada
| | - Giselle A Suero-Abreu
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA; Biomedical Imaging, New York University School of Medicine, New York, NY, USA
| | - Charles Watson
- Health Sciences, Curtin University, Perth, Western Australia, Australia
| | - Alexandra L Joyner
- Developmental Biology Program, Sloan-Kettering Institute, New York, NY, USA
| | - Daniel H Turnbull
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA; Biomedical Imaging, New York University School of Medicine, New York, NY, USA; Molecular Biophysics Graduate Programs, New York University School of Medicine, New York, NY, USA; Department of Radiology, New York University School of Medicine, New York, NY, USA; Department of Pathology, New York University School of Medicine, New York, NY, USA.
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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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Lewis CM, Graves SA, Hernandez R, Valdovinos HF, Barnhart TE, Cai W, Meyerand ME, Nickles RJ, Suzuki M. ⁵²Mn production for PET/MRI tracking of human stem cells expressing divalent metal transporter 1 (DMT1). Am J Cancer Res 2015; 5:227-39. [PMID: 25553111 PMCID: PMC4279187 DOI: 10.7150/thno.10185] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 10/22/2014] [Indexed: 12/26/2022] Open
Abstract
There is a growing demand for long-term in vivo stem cell imaging for assessing cell therapy techniques and guiding therapeutic decisions. This work develops the production of 52Mn and establishes proof of concept for the use of divalent metal transporter 1 (DMT1) as a positron emission tomography (PET) and magnetic resonance imaging (MRI) reporter gene for stem cell tracking in the rat brain. 52Mn was produced via proton irradiation of a natural chromium target. In a comparison of two 52Mn separation methods, solvent-solvent extraction was preferred over ion exchange chromatography because of reduced chromium impurities and higher 52Mn recovery. In vitro uptake of Mn-based PET and MRI contrast agents (52Mn2+ and Mn2+, respectively) was enhanced in DMT1 over-expressing human neural progenitor cells (hNPC-DMT1) compared to wild-type control cells (hNPC-WT). After cell transplantation in the rat striatum, increased uptake of Mn-based contrast agents in grafted hNPC-DMT1 was detected in in vivo manganese-enhanced MRI (MEMRI) and ex vivo PET and autoradiography. These initial studies indicate that this approach holds promise for dual-modality PET/MR tracking of transplanted stem cells in the central nervous system and prompt further investigation into the clinical applicability of this technique.
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Bartelle BB, Mana MD, Suero-Abreu GA, Rodriguez JJ, Turnbull DH. Engineering an effective Mn-binding MRI reporter protein by subcellular targeting. Magn Reson Med 2014; 74:1750-7. [PMID: 25522343 DOI: 10.1002/mrm.25566] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 10/24/2014] [Accepted: 11/17/2014] [Indexed: 12/23/2022]
Abstract
PURPOSE Manganese (Mn) is an effective contrast agent and biologically active metal, which has been widely used for Mn-enhanced MRI (MEMRI). The purpose of this study was to develop and test a Mn binding protein for use as a genetic reporter for MEMRI. METHODS The bacterial Mn-binding protein, MntR was identified as a candidate reporter protein. MntR was engineered for expression in mammalian cells, and targeted to different subcellular organelles, including the Golgi Apparatus where cellular Mn is enriched. Transfected HEK293 cells and B16 melanoma cells were tested in vitro and in vivo, using immunocytochemistry, MR imaging and relaxometry. RESULTS Subcellular targeting of MntR to the cytosol, endoplasmic reticulum and Golgi apparatus was verified with immunocytochemistry. After targeting to the Golgi, MntR expression produced robust R1 changes and T1 contrast in cells, in vitro and in vivo. Co-expression with the divalent metal transporter DMT1, a previously described Mn-based reporter, further enhanced contrast in B16 cells in culture, but in the in vivo B16 tumor model tested was not significantly better than MntR alone. CONCLUSION This second-generation reporter system both expands the capabilities of genetically encoded reporters for imaging with MEMRI and provides important insights into the mechanisms of Mn biology which create endogenous MEMRI contrast.
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Affiliation(s)
- Benjamin B Bartelle
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Miyeko D Mana
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York, USA.,Koch Institute of Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Giselle A Suero-Abreu
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York, USA
| | - Joe J Rodriguez
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York, USA
| | - Daniel H Turnbull
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York, USA.,Departments of Radiology and Pathology, New York University School of Medicine, New York, New York, USA
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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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50
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Cho IK, Moran SP, Paudyal R, Piotrowska-Nitsche K, Cheng PH, Zhang X, Mao H, Chan AW. Longitudinal monitoring of stem cell grafts in vivo using magnetic resonance imaging with inducible maga as a genetic reporter. Am J Cancer Res 2014; 4:972-89. [PMID: 25161700 PMCID: PMC4143941 DOI: 10.7150/thno.9436] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 06/29/2014] [Indexed: 01/06/2023] Open
Abstract
PURPOSE The ability to longitudinally monitor cell grafts and assess their condition is critical for the clinical translation of stem cell therapy in regenerative medicine. Developing an inducible genetic magnetic resonance imaging (MRI) reporter will enable non-invasive and longitudinal monitoring of stem cell grafts in vivo. METHODS MagA, a bacterial gene involved in the formation of iron oxide nanocrystals, was genetically modified for in vivo monitoring of cell grafts by MRI. Inducible expression of MagA was regulated by a Tet-On (Tet) switch. A mouse embryonic stem cell-line carrying Tet-MagA (mESC-MagA) was established by lentivirus transduction. The impact of expressing MagA in mESCs was evaluated via proliferation assay, cytotoxicity assay, teratoma formation, MRI, and inductively coupled plasma atomic emission spectroscopy (ICP-OES). Mice were grafted with mESCs with and without MagA (mESC-MagA and mESC-WT). The condition of cell grafts with induced "ON" and non-induced "OFF" expression of MagA was longitudinally monitored in vivo using a 7T MRI scanner. After imaging, whole brain samples were harvested for histological assessment. RESULTS Expression of MagA in mESCs resulted in significant changes in the transverse relaxation rate (R2 or 1/T2) and susceptibility weighted MRI contrast. The pluripotency of mESCs carrying MagA was not affected in vitro or in vivo. Intracranial mESC-MagA grafts generated sufficient T2 and susceptibility weighted contrast at 7T. The mESC-MagA grafts can be monitored by MRI longitudinally upon induced expression of MagA by administering doxycycline (Dox) via diet. CONCLUSION Our results demonstrate MagA could be used to monitor cell grafts noninvasively, longitudinally, and repetitively, enabling the assessment of cell graft conditions in vivo.
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