1
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Intrabiliary infusion of naked DNA vectors targets periportal hepatocytes in mice. MOLECULAR THERAPY - METHODS & CLINICAL DEVELOPMENT 2022; 27:352-367. [DOI: 10.1016/j.omtm.2022.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022]
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2
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Arias A, Manubens-Gil L, Dierssen M. Fluorescent transgenic mouse models for whole-brain imaging in health and disease. Front Mol Neurosci 2022; 15:958222. [PMID: 36211979 PMCID: PMC9538927 DOI: 10.3389/fnmol.2022.958222] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 08/08/2022] [Indexed: 11/25/2022] Open
Abstract
A paradigm shift is occurring in neuroscience and in general in life sciences converting biomedical research from a descriptive discipline into a quantitative, predictive, actionable science. Living systems are becoming amenable to quantitative description, with profound consequences for our ability to predict biological phenomena. New experimental tools such as tissue clearing, whole-brain imaging, and genetic engineering technologies have opened the opportunity to embrace this new paradigm, allowing to extract anatomical features such as cell number, their full morphology, and even their structural connectivity. These tools will also allow the exploration of new features such as their geometrical arrangement, within and across brain regions. This would be especially important to better characterize brain function and pathological alterations in neurological, neurodevelopmental, and neurodegenerative disorders. New animal models for mapping fluorescent protein-expressing neurons and axon pathways in adult mice are key to this aim. As a result of both developments, relevant cell populations with endogenous fluorescence signals can be comprehensively and quantitatively mapped to whole-brain images acquired at submicron resolution. However, they present intrinsic limitations: weak fluorescent signals, unequal signal strength across the same cell type, lack of specificity of fluorescent labels, overlapping signals in cell types with dense labeling, or undetectable signal at distal parts of the neurons, among others. In this review, we discuss the recent advances in the development of fluorescent transgenic mouse models that overcome to some extent the technical and conceptual limitations and tradeoffs between different strategies. We also discuss the potential use of these strains for understanding disease.
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Affiliation(s)
- Adrian Arias
- Department of System Biology, Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Linus Manubens-Gil
- Institute for Brain and Intelligence, Southeast University, Nanjing, China
| | - Mara Dierssen
- Department of System Biology, Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Experimental and Health Sciences, University Pompeu Fabra, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Barcelona, Spain
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Wang Y, Ma G, Gao G, Tao J, Cao W, Sun H, Ma F, Zhang Y, Wei Y, Tian M. Bioimaging of Dissolvable Microneedle Arrays: Challenges and Opportunities. RESEARCH (WASHINGTON, D.C.) 2022; 2022:9758491. [PMID: 36034102 PMCID: PMC9368514 DOI: 10.34133/2022/9758491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 06/10/2022] [Indexed: 11/29/2022]
Abstract
The emergence of microneedle arrays (MNAs) as a novel, simple, and minimally invasive administration approach largely addresses the challenges of traditional drug delivery. In particular, the dissolvable MNAs act as a promising, multifarious, and well-controlled platform for micro-nanotransport in medical research and cosmetic formulation applications. The effective delivery mostly depends on the behavior of the MNAs penetrated into the body, and accurate assessment is urgently needed. Advanced imaging technologies offer high sensitivity and resolution visualization of cross-scale, multidimensional, and multiparameter information, which can be used as an important aid for the evaluation and development of new MNAs. The combination of MNA technology and imaging can generate considerable new knowledge in a cost-effective manner with regards to the pharmacokinetics and bioavailability of active substances for the treatment of various diseases. In addition, noninvasive imaging techniques allow rapid, receptive assessment of transdermal penetration and drug deposition in various tissues, which could greatly facilitate the translation of experimental MNAs into clinical application. Relying on the recent promising development of bioimaging, this review is aimed at summarizing the current status, challenges, and future perspective on in vivo assessment of MNA drug delivery by various imaging technologies.
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Affiliation(s)
- Yanni Wang
- Laboratory of Biologics and Biomaterials, College of Pharmacy, Zhejiang University of Technology, Hangzhou 310014, China
| | - Gehua Ma
- College of Computer Science and Technology, Zhejiang University, Hangzhou 310027, China
| | - Guangzhi Gao
- Laboratory of Biologics and Biomaterials, College of Pharmacy, Zhejiang University of Technology, Hangzhou 310014, China
| | - Ji Tao
- Human Phenome Institute, Fudan University, Shanghai 201203, China
| | - Wenzhao Cao
- Human Phenome Institute, Fudan University, Shanghai 201203, China
| | - Haohao Sun
- College of Information Engineering, Zhejiang University of Technology, Hangzhou 310023, China
| | - Fengsen Ma
- Laboratory of Biologics and Biomaterials, College of Pharmacy, Zhejiang University of Technology, Hangzhou 310014, China
- Life Science Research Center, Frontier Crossing Institute, Zhejiang University of Technology, Hangzhou 310023, China
| | - Yilong Zhang
- Engineering Research Center of Intelligent Sensing and System, Ministry of Education, Hangzhou 310023, China
- College of Computer Science and Technology, Zhejiang University of Technology, Hangzhou 310023, China
| | - Yen Wei
- Department of Chemistry and the Tsinghua Center for Frontier Polymer Research, Tsinghua University, Beijing 100084, China
| | - Mei Tian
- Human Phenome Institute, Fudan University, Shanghai 201203, China
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4
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Vaghela R, Arkudas A, Horch RE, Hessenauer M. Actually Seeing What Is Going on - Intravital Microscopy in Tissue Engineering. Front Bioeng Biotechnol 2021; 9:627462. [PMID: 33681162 PMCID: PMC7925911 DOI: 10.3389/fbioe.2021.627462] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 01/26/2021] [Indexed: 12/21/2022] Open
Abstract
Intravital microscopy (IVM) study approach offers several advantages over in vitro, ex vivo, and 3D models. IVM provides real-time imaging of cellular events, which provides us a comprehensive picture of dynamic processes. Rapid improvement in microscopy techniques has permitted deep tissue imaging at a higher resolution. Advances in fluorescence tagging methods enable tracking of specific cell types. Moreover, IVM can serve as an important tool to study different stages of tissue regeneration processes. Furthermore, the compatibility of different tissue engineered constructs can be analyzed. IVM is also a promising approach to investigate host reactions on implanted biomaterials. IVM can provide instant feedback for improvising tissue engineering strategies. In this review, we aim to provide an overview of the requirements and applications of different IVM approaches. First, we will discuss the history of IVM development, and then we will provide an overview of available optical modalities including the pros and cons. Later, we will summarize different fluorescence labeling methods. In the final section, we will discuss well-established chronic and acute IVM models for different organs.
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Affiliation(s)
- Ravikumar Vaghela
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Andreas Arkudas
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Raymund E Horch
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Maximilian Hessenauer
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
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5
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Huang Q, Cohen MA, Alsina FC, Devlin G, Garrett A, McKey J, Havlik P, Rakhilin N, Wang E, Xiang K, Mathews P, Wang L, Bock C, Ruthig V, Wang Y, Negrete M, Wong CW, Murthy PKL, Zhang S, Daniel AR, Kirsch DG, Kang Y, Capel B, Asokan A, Silver DL, Jaenisch R, Shen X. Intravital imaging of mouse embryos. Science 2020; 368:181-186. [PMID: 32273467 PMCID: PMC7646360 DOI: 10.1126/science.aba0210] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 03/16/2020] [Indexed: 12/11/2022]
Abstract
Embryonic development is a complex process that is unamenable to direct observation. In this study, we implanted a window to the mouse uterus to visualize the developing embryo from embryonic day 9.5 to birth. This removable intravital window allowed manipulation and high-resolution imaging. In live mouse embryos, we observed transient neurotransmission and early vascularization of neural crest cell (NCC)-derived perivascular cells in the brain, autophagy in the retina, viral gene delivery, and chemical diffusion through the placenta. We combined the imaging window with in utero electroporation to label and track cell division and movement within embryos and observed that clusters of mouse NCC-derived cells expanded in interspecies chimeras, whereas adjacent human donor NCC-derived cells shrank. This technique can be combined with various tissue manipulation and microscopy methods to study the processes of development at unprecedented spatiotemporal resolution.
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Affiliation(s)
- Qiang Huang
- Department of Pediatric Surgery, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China.
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Malkiel A Cohen
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Fernando C Alsina
- Department of Molecular Genetics and Microbiology, School of Medicine, Duke University, Durham, NC, USA
| | - Garth Devlin
- Department of Surgery, School of Medicine, Duke University, Durham, NC, USA
| | - Aliesha Garrett
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Jennifer McKey
- Department of Cell Biology, School of Medicine, Duke University, Durham, NC, USA
| | - Patrick Havlik
- Department of Surgery, School of Medicine, Duke University, Durham, NC, USA
| | - Nikolai Rakhilin
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Ergang Wang
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Kun Xiang
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Parker Mathews
- Division of Hematologic Malignancies and Cellular Therapy, Duke University Medical Center, Durham, NC, USA
| | - Lihua Wang
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Cheryl Bock
- Duke Cancer Institute, School of Medicine, Duke University, Durham, NC, USA
| | - Victor Ruthig
- Department of Cell Biology, School of Medicine, Duke University, Durham, NC, USA
| | - Yi Wang
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Marcos Negrete
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Chi Wut Wong
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Preetish K L Murthy
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA
| | - Shupei Zhang
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Andrea R Daniel
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA
| | - David G Kirsch
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA
- Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Yubin Kang
- Division of Hematologic Malignancies and Cellular Therapy, Duke University Medical Center, Durham, NC, USA
| | - Blanche Capel
- Department of Cell Biology, School of Medicine, Duke University, Durham, NC, USA
| | - Aravind Asokan
- Department of Surgery, School of Medicine, Duke University, Durham, NC, USA
| | - Debra L Silver
- Department of Molecular Genetics and Microbiology, School of Medicine, Duke University, Durham, NC, USA
| | - Rudolf Jaenisch
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Xiling Shen
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, USA.
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6
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Laser Scanning Microscopy of Yersinia pestis Infected Tissues. Methods Mol Biol 2019. [PMID: 31177432 DOI: 10.1007/978-1-4939-9541-7_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Laser scanning microscopy (LSM) is a technology that allows for direct observations of host-pathogen interactions during infection. Two of the most available forms of LSM are confocal and two-photon LSM. In addition to high resolution and contrast, these two technologies also provide high excitation penetrance in unsectioned samples. High penetrance allows for imaging of layers of tissue that are difficult to image with other more conventional microscopy approaches. Thus, confocal and two-photon LSM open the possibility of observing infection in a three-dimensional context, where the natural architecture of a tissue is preserved. Few studies have used LSM technology to gain insights into Yersinia pestis pathogenesis in the mammalian host. The use of LSM in the plague field has an enormous potential for the discovery of the mechanisms that lie behind key aspects of pathogenesis such as colonization, dissemination, and tissue damage. This chapter provides guidance for the implementation of confocal or two-photon LSM to study Y. pestis interactions with the host in unsectioned tissues. This document provides specific instructions applied to imaging of Y. pestis, and also discusses relevant aspects of imaging, such as the operation of laser scanning microscopes and the use of fluorescent probes.
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Abstract
Mouse genetic approaches when combined with live imaging tools are revolutionizing our current understanding of mammalian developmental biology. The availability and improvement of a wide variety of genetically encoded fluorescent proteins have provided indispensable tools to visualize cells and subcellular features in living organisms. It is now possible to generate genetically modified mouse lines expressing several spectrally distinct fluorescent proteins in a tissue-specific or -inducible manner. Such reporter-expressing lines make it possible to image dynamic cellular behaviors in the context of living embryos undergoing normal or aberrant development. As with all viviparous mammals, mouse embryos develop within the uterus, and so live imaging experiments require culture conditions that closely mimic the in vivo environment. Over the past decades, significant advances have been made in developing conditions for culturing both pre- and postimplantation-stage mouse embryos. In this chapter, we discuss routine methods for ex utero culture of preimplantation- and postimplantation-stage mouse embryos. In particular, we describe protocols for collecting mouse embryos of various stages, setting up culture conditions for their ex utero culture and imaging, and using laser scanning confocal microscopy to visualize live processes in mouse embryos expressing fluorescent reporters.
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Affiliation(s)
- Sonja Nowotschin
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Vidur Garg
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Anna Piliszek
- Department of Experimental Embryology, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzębiec, Poland
| | - Anna-Katerina Hadjantonakis
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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8
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Carroll P, Muwanguzi-Karugaba J, Parish T. Codon-optimized DsRed fluorescent protein for use in Mycobacterium tuberculosis. BMC Res Notes 2018; 11:685. [PMID: 30285840 PMCID: PMC6167837 DOI: 10.1186/s13104-018-3798-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 09/27/2018] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE We have previously codon-optimized a number of red fluorescent proteins for use in Mycobacterium tuberculosis (mCherry, tdTomato, Turbo-635). We aimed to expand this repertoire to include DsRed, another widely used and flexible red fluorescent protein. RESULTS We generated expression constructs with a full length DsRed under the control of one of three strong, constitutive promoters (Phsp60, PrpsA or PG13) for use in mycobacteria. We confirmed that full length DsRed (225 amino acids) was expressed and fluoresced brightly. In contrast to mCherry, truncated versions of DsRed lacking several amino acids at the N-terminus were not functional. Thus, we have expanded the repertoire of optimized fluorescent proteins for mycobacteria.
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Affiliation(s)
- Paul Carroll
- Queen Mary University of London, Barts & The London School of Medicine and Dentistry, London, UK
| | | | - Tanya Parish
- Queen Mary University of London, Barts & The London School of Medicine and Dentistry, London, UK
- Infectious Disease Research Institute, Seattle, WA 98102 USA
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Stabler CL, Long RC, Constantinidis I, Sambanis A. In Vivo Noninvasive Monitoring of a Tissue Engineered Construct Using 1H NMR Spectroscopy. Cell Transplant 2017; 14:139-49. [PMID: 15881423 DOI: 10.3727/000000005783983197] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Direct, noninvasive monitoring of tissue engineered substitutes containing live, functional cells would provide valuable information on dynamic changes that occur postimplantation. Such changes include remodeling both within the construct and at the interface of the implant with the surrounding host tissue, and may result in changes in the number of viable cells in the construct. This study investigated the use of 1H NMR spectroscopy in noninvasively monitoring the viable cell number within a tissue engineered construct in vivo. The construct consisted of mouse βTC3 insulinomas in a disk-shaped agarose gel, surrounded by a cell-free agarose gel layer. Localized 1H NMR spectra were acquired from within implanted constructs, and the total choline resonance was measured. Critical issues that had to be addressed in accurately quantifying total choline from the implanted cells included avoiding signal from host tissue and correcting for interfering signal from diffusing solutes. In vivo NMR measurements were correlated with MTT assays and NMR measurements performed in vitro on explanted constructs. Total choline measurements accurately and noninvasively quantified viable βTC3 cell numbers in vivo, in the range of 1 × 106 to more than 14 × 106 cells, and monitored changes in viable cell number that occurred in the same construct over time. This is the first study using NMR techniques to monitor viable cell numbers in an implanted tissue substitute. It established architectural characteristics that a construct should have to be amenable to NMR monitoring, and it set the foundation for future in vivo investigations with other tissue engineered implants.
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Affiliation(s)
- C L Stabler
- Georgia Institute of Technology/Emory University Center for the Engineering of Living Tissues, 315 Ferst Drive, Atlanta, GA 30332-0363, USA
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10
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Reliable Genetic Labeling of Adult-Born Dentate Granule Cells Using Ascl1 CreERT2 and Glast CreERT2 Murine Lines. J Neurosci 2016; 35:15379-90. [PMID: 26586824 DOI: 10.1523/jneurosci.2345-15.2015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Newly generated dentate granule cells (GCs) are relevant for input discrimination in the adult hippocampus. Yet, their precise contribution to information processing remains unclear. To address this question, it is essential to develop approaches to precisely label entire cohorts of adult-born GCs. In this work, we used genetically modified mice to allow conditional expression of tdTomato (Tom) in adult-born GCs and characterized their development and functional integration. Ascl1(CreERT2);CAG(floxStopTom) and Glast(CreERT2);CAG(floxStopTom) mice resulted in indelible expression of Tom in adult neural stem cells and their lineage upon tamoxifen induction. Whole-cell recordings were performed to measure intrinsic excitability, firing behavior, and afferent excitatory connectivity. Developing GCs were also staged by the expression of early and late neuronal markers. The slow development of adult-born GCs characterized here is consistent with previous reports using retroviral approaches that have revealed that a mature phenotype is typically achieved after 6-8 weeks. Our findings demonstrate that Ascl1(CreERT2) and Glast(CreERT2) mouse lines enable simple and reliable labeling of adult-born GC lineages within restricted time windows. Therefore, these mice greatly facilitate tagging new neurons and manipulating their activity, required for understanding adult neurogenesis in the context of network remodeling, learning, and behavior. SIGNIFICANCE STATEMENT Our study shows that Ascl1(CreERT2) and Glast(CreERT2) mice lines can be used to label large cohorts of adult-born dentate granule cells with excellent time resolution. Neurons labeled in this manner display developmental and functional profiles that are in full agreement with previous findings using thymidine analogs and retroviral labeling, thus providing an alternative approach to tackle fundamental questions on circuit remodeling. Because of the massive neuronal targeting and the simplicity of this method, genetic labeling will contribute to expand research on adult neurogenesis.
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11
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Deleidi M, Yu C. Genome editing in pluripotent stem cells: research and therapeutic applications. Biochem Biophys Res Commun 2016; 473:665-74. [PMID: 26930470 DOI: 10.1016/j.bbrc.2016.02.113] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 02/26/2016] [Indexed: 12/26/2022]
Abstract
Recent progress in human pluripotent stem cell (hPSC) and genome editing technologies has opened up new avenues for the investigation of human biology in health and disease as well as the development of therapeutic applications. Gene editing approaches with programmable nucleases have been successfully established in hPSCs and applied to study gene function, develop novel animal models and perform genetic and chemical screens. Several studies now show the successful editing of disease-linked alleles in somatic and patient-derived induced pluripotent stem cells (iPSCs) as well as in animal models. Importantly, initial clinical trials have shown the safety of programmable nucleases for ex vivo somatic gene therapy. In this context, the unlimited proliferation potential and the pluripotent properties of iPSCs may offer advantages for gene targeting approaches. However, many technical and safety issues still need to be addressed before genome-edited iPSCs are translated into the clinical setting. Here, we provide an overview of the available genome editing systems and discuss opportunities and perspectives for their application in basic research and clinical practice, with a particular focus on hPSC based research and gene therapy approaches. Finally, we discuss recent research on human germline genome editing and its social and ethical implications.
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Affiliation(s)
- Michela Deleidi
- German Center for Neurodegenerative Diseases (DZNE) Tübingen within the Helmholtz Association, Tübingen, Germany; Hertie Institute for Clinical Brain Research, University of Tübingen, Germany.
| | - Cong Yu
- Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo, New York, USA
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12
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Impact of Environmental Factors on Bacteriocin Promoter Activity in Gut-Derived Lactobacillus salivarius. Appl Environ Microbiol 2015; 81:7851-9. [PMID: 26341205 DOI: 10.1128/aem.02339-15] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 08/30/2015] [Indexed: 12/27/2022] Open
Abstract
Bacteriocin production is regarded as a desirable probiotic trait that aids in colonization and persistence in the gastrointestinal tract (GIT). Strains of Lactobacillus salivarius, a species associated with the GIT, are regarded as promising probiotic candidates and have a number of associated bacteriocins documented to date. These include multiple class IIb bacteriocins (salivaricin T, salivaricin P, and ABP-118) and the class IId bacteriocin bactofencin A, which show activity against medically important pathogens. However, the production of a bacteriocin in laboratory media does not ensure production under stressful environmental conditions, such as those encountered within the GIT. To allow this issue to be addressed, the promoter regions located upstream of the structural genes encoding the L. salivarius bacteriocins mentioned above were fused to a number of reporter proteins (green fluorescent protein [GFP], red fluorescent protein [RFP], and luciferase [Lux]). Of these, only transcriptional fusions to GFP generated signals of sufficient strength to enable the study of promoter activity in L. salivarius. While analysis of the class IIb bacteriocin promoter regions indicated relatively weak GFP expression, assessment of the promoter of the antistaphylococcal bacteriocin bactofencin A revealed a strong promoter that is most active in the absence of the antimicrobial peptide and is positively induced in the presence of mild environmental stresses, including simulated gastric fluid. Taken together, these data provide information on factors that influence bacteriocin production, which will assist in the development of strategies to optimize in vivo and in vitro production of these antimicrobials.
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13
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Single cells get together: High-resolution approaches to study the dynamics of early mouse development. Semin Cell Dev Biol 2015; 47-48:92-100. [PMID: 26183190 DOI: 10.1016/j.semcdb.2015.06.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 06/17/2015] [Accepted: 06/19/2015] [Indexed: 11/22/2022]
Abstract
Embryonic development is a complex and highly dynamic process during which individual cells interact with one another, adopt different identities and organize themselves in three-dimensional space to generate an entire organism. Recent technical developments in genomics and high-resolution quantitative imaging are making it possible to study cellular populations at single-cell resolution and begin to integrate different inputs, for example genetic, physical and chemical factors, that affect cell differentiation over spatial and temporal scales. The preimplantation mouse embryo allows the analysis of cell fate decisions in vivo with high spatiotemporal resolution. In this review we highlight how the application of live imaging and single-cell resolution analysis pipelines is providing an unprecedented level of insight on the processes that shape the earliest stages of mammalian development.
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14
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Murphey DK, Herman AM, Arenkiel BR. Dissecting inhibitory brain circuits with genetically-targeted technologies. Front Neural Circuits 2014; 8:124. [PMID: 25368555 PMCID: PMC4201106 DOI: 10.3389/fncir.2014.00124] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 09/22/2014] [Indexed: 12/14/2022] Open
Abstract
The evolution of genetically targeted tools has begun to allow us to dissect anatomically and functionally heterogeneous interneurons, and to probe circuit function from synapses to behavior. Over the last decade, these tools have been used widely to visualize neurons in a cell type-specific manner, and engage them to activate and inactivate with exquisite precision. In this process, we have expanded our understanding of interneuron diversity, their functional connectivity, and how selective inhibitory circuits contribute to behavior. Here we discuss the relative assets of genetically encoded fluorescent proteins (FPs), viral tracing methods, optogenetics, chemical genetics, and biosensors in the study of inhibitory interneurons and their respective circuits.
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Affiliation(s)
- Dona K Murphey
- Department of Neurology, Baylor College of Medicine Houston, TX, USA
| | - Alexander M Herman
- Program in Developmental Biology, Baylor College of Medicine Houston, TX, USA
| | - Benjamin R Arenkiel
- Program in Developmental Biology, Baylor College of Medicine Houston, TX, USA ; Department of Molecular and Human Genetics, Baylor College of Medicine Houston, TX, USA ; Department of Neuroscience, Baylor College of Medicine Houston, TX, USA ; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital Houston, TX, USA
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15
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Chiou SH, Kim-Kiselak C, Risca VI, Heimann MK, Chuang CH, Burds AA, Greenleaf WJ, Jacks TE, Feldser DM, Winslow MM. A conditional system to specifically link disruption of protein-coding function with reporter expression in mice. Cell Rep 2014; 7:2078-86. [PMID: 24931605 DOI: 10.1016/j.celrep.2014.05.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 04/04/2014] [Accepted: 05/15/2014] [Indexed: 10/25/2022] Open
Abstract
Conditional gene deletion in mice has contributed immensely to our understanding of many biological and biomedical processes. Despite an increasing awareness of nonprotein-coding functional elements within protein-coding transcripts, current gene-targeting approaches typically involve simultaneous ablation of noncoding elements within targeted protein-coding genes. The potential for protein-coding genes to have additional noncoding functions necessitates the development of novel genetic tools capable of precisely interrogating individual functional elements. We present a strategy that couples Cre/loxP-mediated conditional gene disruption with faithful GFP reporter expression in mice in which Cre-mediated stable inversion of a splice acceptor-GFP-splice donor cassette concurrently disrupts protein production and creates a GFP fusion product. Importantly, cassette inversion maintains physiologic transcript structure, thereby ensuring proper microRNA-mediated regulation of the GFP reporter, as well as maintaining expression of nonprotein-coding elements. To test this potentially generalizable strategy, we generated and analyzed mice with this conditional knockin reporter targeted to the Hmga2 locus.
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Affiliation(s)
- Shin-Heng Chiou
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA
| | - Caroline Kim-Kiselak
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Viviana I Risca
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA
| | - Megan K Heimann
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Chen-Hua Chuang
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA
| | - Aurora A Burds
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - William J Greenleaf
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA
| | - Tyler E Jacks
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - David M Feldser
- Department of Cancer Biology, University of Pennsylvania, Philadelphia, PA 19104-6160, USA; Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104-6160, USA
| | - Monte M Winslow
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA; Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305-5324, USA; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305-5456, USA.
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16
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Lou X, Schiegg M, Hamprecht FA. Active structured learning for cell tracking: algorithm, framework, and usability. IEEE TRANSACTIONS ON MEDICAL IMAGING 2014; 33:849-860. [PMID: 24710154 DOI: 10.1109/tmi.2013.2296937] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
One distinguishing property of life is its temporal dynamics, and it is hence only natural that time lapse experiments play a crucial role in modern biomedical research areas such as signaling pathways, drug discovery or developmental biology. Such experiments yield a very large number of images that encode complex cellular activities, and reliable automated cell tracking emerges naturally as a prerequisite for further quantitative analysis. However, many existing cell tracking methods are restricted to using only a small number of features to allow for manual tweaking. In this paper, we propose a novel cell tracking approach that embraces a powerful machine learning technique to optimize the tracking parameters based on user annotated tracks. Our approach replaces the tedious parameter tuning with parameter learning and allows for the use of a much richer set of complex tracking features, which in turn affords superior prediction accuracy. Furthermore, we developed an active learning approach for efficient training data retrieval, which reduces the annotation effort to only 17%. In practical terms, our approach allows life science researchers to inject their expertise in a more intuitive and direct manner. This process is further facilitated by using a glyph visualization technique for ground truth annotation and validation. Evaluation and comparison on several publicly available benchmark sequences show significant performance improvement over recently reported approaches. Code and software tools are provided to the public.
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17
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Rattanapak T, Birchall JC, Young K, Kubo A, Fujimori S, Ishii M, Hook S. Dynamic visualization of dendritic cell-antigen interactions in the skin following transcutaneous immunization. PLoS One 2014; 9:e89503. [PMID: 24586830 PMCID: PMC3933627 DOI: 10.1371/journal.pone.0089503] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 01/21/2014] [Indexed: 11/18/2022] Open
Abstract
Delivery of vaccines into the skin provides many advantages over traditional parenteral vaccination and is a promising approach due to the abundance of antigen presenting cells (APC) residing in the skin including Langerhans cells (LC) and dermal dendritic cells (DDC). However, the main obstacle for transcutaneous immunization (TCI) is the effective delivery of the vaccine through the stratum corneum (SC) barrier to the APC in the deeper skin layers. This study therefore utilized microneedles (MN) and a lipid-based colloidal delivery system (cubosomes) as a synergistic approach for the delivery of vaccines to APC in the skin. The process of vaccine uptake and recruitment by specific types of skin APC was investigated in real-time over 4 hours in B6.Cg-Tg (Itgax-EYFP) 1 Mnz/J mice by two-photon microscopy. Incorporation of the vaccine into a particulate delivery system and the use of MN preferentially increased vaccine antigen uptake by a highly motile subpopulation of skin APC known as CD207⁺ DC. No uptake of antigen or any response to immunisation by LC could be detected.
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Affiliation(s)
| | - James C Birchall
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom
| | - Katherine Young
- School of Pharmacy, University of Otago, Dunedin, New Zealand
| | - Atsuko Kubo
- Laboratory of Cellular Dynamics, Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Sayumi Fujimori
- Laboratory of Cellular Dynamics, Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Masaru Ishii
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences and Laboratory of Cellular Dynamics, Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Sarah Hook
- School of Pharmacy, University of Otago, Dunedin, New Zealand
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18
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Molitoris BA. Using 2-photon microscopy to understand albuminuria. TRANSACTIONS OF THE AMERICAN CLINICAL AND CLIMATOLOGICAL ASSOCIATION 2014; 125:343-56; discussion 356-7. [PMID: 25125750 PMCID: PMC4112674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Intravital 2-photon microscopy, along with the development of fluorescent probes and innovative software, has rapidly advanced the study of intracellular and intercellular processes at the organ level. Researchers can quantify the distribution, behavior, and dynamic interactions of up to four labeled chemical probes and proteins simultaneously and repeatedly in four dimensions (3D + time) with subcellular resolution in real time. Transgenic fluorescently labeled proteins, delivery of plasmids, and photo-activatable probes enhance these possibilities. Thus, multi-photon microscopy has greatly extended our ability to understand cell biology intra-vitally at cellular and subcellular levels. For example, evaluation of rat surface glomeruli and accompanying proximal tubules has shown the long held paradigm regarding limited albumin filtration under physiologic conditions is to be questioned. Furthermore, the role of proximal tubules in determining albuminuria under physiologic and disease conditions was supported by direct visualization and quantitative analysis.
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19
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Rattanapak T, Birchall J, Young K, Ishii M, Meglinski I, Rades T, Hook S. Transcutaneous immunization using microneedles and cubosomes: Mechanistic investigations using Optical Coherence Tomography and Two-Photon Microscopy. J Control Release 2013; 172:894-903. [DOI: 10.1016/j.jconrel.2013.08.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/07/2013] [Accepted: 08/13/2013] [Indexed: 12/17/2022]
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20
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Zhu Z, Huangfu D. Human pluripotent stem cells: an emerging model in developmental biology. Development 2013; 140:705-17. [PMID: 23362344 DOI: 10.1242/dev.086165] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Developmental biology has long benefited from studies of classic model organisms. Recently, human pluripotent stem cells (hPSCs), including human embryonic stem cells and human induced pluripotent stem cells, have emerged as a new model system that offers unique advantages for developmental studies. Here, we discuss how studies of hPSCs can complement classic approaches using model organisms, and how hPSCs can be used to recapitulate aspects of human embryonic development 'in a dish'. We also summarize some of the recently developed genetic tools that greatly facilitate the interrogation of gene function during hPSC differentiation. With the development of high-throughput screening technologies, hPSCs have the potential to revolutionize gene discovery in mammalian development.
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Affiliation(s)
- Zengrong Zhu
- Developmental Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA.
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21
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Luche H, Nageswara Rao T, Kumar S, Tasdogan A, Beckel F, Blum C, Martins VC, Rodewald HR, Fehling HJ. In vivo fate mapping identifies pre-TCRα expression as an intra- and extrathymic, but not prethymic, marker of T lymphopoiesis. ACTA ACUST UNITED AC 2013; 210:699-714. [PMID: 23509324 PMCID: PMC3620354 DOI: 10.1084/jem.20122609] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A novel pre-TCRα (pTα) reporter mouse reveals that expression of pTα is confined to the T lineage and does not occur on prethymic progenitors. Expression of the pre–T cell receptor α (pTα) gene has been exploited in previous studies as a molecular marker to identify tiny cell populations in bone marrow (BM) and blood that were suggested to contain physiologically relevant thymus settling progenitors (TSPs). But to what extent these cells genuinely contribute to thymopoiesis has remained obscure. We have generated a novel pTαiCre knockin mouse line and performed lineage-tracing experiments to precisely quantitate the contribution of pTα-expressing progenitors to distinct differentiation pathways and to the genealogy of mature hematopoietic cells under physiological in vivo conditions. Using these mice in combination with fluorescent reporter strains, we observe highly consistent labeling patterns that identify pTα expression as a faithful molecular marker of T lineage commitment. Specifically, the fate of pTα-expressing progenitors was found to include all αβ and most γδ T cells but, in contrast to previous assumptions, to exclude B, NK, and thymic dendritic cells. Although we could detect small numbers of T cell progenitors with a history of pTα expression in BM and blood, our data clearly exclude these populations as physiologically important precursors of thymopoiesis and indicate that they instead belong to a pathway of T cell maturation previously defined as extrathymic.
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Affiliation(s)
- Hervé Luche
- Institute of Immunology, University Clinics Ulm, D-89081 Ulm, Germany
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22
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Live imaging, identifying, and tracking single cells in complex populations in vivo and ex vivo. Methods Mol Biol 2013; 1052:109-23. [PMID: 23640250 DOI: 10.1007/7651_2013_19] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Advances in optical imaging technologies combined with the use of genetically encoded fluorescent proteins have enabled the visualization of stem cells over extensive periods of time in vivo and ex vivo. The generation of genetically encoded fluorescent protein reporters that are fused with subcellularly localized proteins, such as human histone H2B, has made it possible to direct fluorescent protein reporters to specific subcellular structures and identify single cells in complex populations. This facilitates the visualization of cellular behaviors such as division, movement, and apoptosis at a single-cell resolution and, in principle, allows the prospective and retrospective tracking towards determining the lineage of each cell.
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23
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den Adel B, Bovens SM, Boekhorst BT, Strijkers GJ, Poelmann RE, van der Weerd L, Pasterkamp G. Histological validation of iron-oxide and gadolinium based MRI contrast agents in experimental atherosclerosis: The do's and don't's. Atherosclerosis 2012; 225:274-80. [DOI: 10.1016/j.atherosclerosis.2012.07.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 07/17/2012] [Accepted: 07/17/2012] [Indexed: 12/22/2022]
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24
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Abstract
Live confocal microscopy of vital fluorescent markers, expressed in mouse embryonic tissues, is a powerful and exciting method to study mammalian embryonic development. This chapter discusses imaging approaches to visualize and characterize dynamic changes of the yolk-sac vasculature and blood flow in mouse embryos. We describe static embryo-culture protocols, which allow maintaining early mouse embryos on the imaging stage for over 24 h. We also describe vital fluorescent-reporter lineages, which can be used to image the developing vasculature and characterize hemodynamics by tracking individual blood cells. Imaging approaches described in this chapter can be used to analyze cardiovascular defects in mutant animals and can provide insights into understanding how genetic signaling pathways and physiological inputs regulate development.
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25
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Nowotschin S, Hadjantonakis AK. Photomodulatable fluorescent proteins for imaging cell dynamics and cell fate. Organogenesis 2012; 5:217-26. [PMID: 20539741 DOI: 10.4161/org.5.4.10939] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 11/09/2009] [Indexed: 12/25/2022] Open
Abstract
An organism arises from the coordinate generation of different cell types and the stereotypical organization of these cells into tissues and organs. Even so, the dynamic behaviors, as well as the ultimate fates, of cells driving the morphogenesis of an organism, or even an individual organ, remain largely unknown. Continued innovations in optical imaging modalities, along with the discovery and evolution of improved genetically-encoded fluorescent protein reporters in combination with model organism, stem cell and tissue engineering paradigms are providing the means to investigate these unresolved questions. The emergence of fluorescent proteins whose spectral properties can be photomodulated is one of the most significant new developments in the field of cell biology where they are primarily used for studying protein dynamics in cells. Likewise, the use of photomodulatable fluorescent proteins holds great promise for use in developmental biology. Photomodulatable fluorescent proteins also represent attractive and emergent tools for studying cell dynamics in complex populations by facilitating the labeling and tracking of individual or defined groups of cells. Here, we review the currently available photomodulatable fluorescent proteins and their application in model organisms. We also discuss prospects for their use in mice, and by extension in embryonic stem cell and tissue engineering paradigms.
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Affiliation(s)
- Sonja Nowotschin
- Developmental Biology Program; Sloan-Kettering Institute; New York, NY USA
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26
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Xenopoulos P, Nowotschin S, Hadjantonakis AK. Live imaging fluorescent proteins in early mouse embryos. Methods Enzymol 2012; 506:361-89. [PMID: 22341233 DOI: 10.1016/b978-0-12-391856-7.00042-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mouse embryonic development comprises highly dynamic and coordinated events that drive key cell lineage specification and morphogenetic events. These processes involve cellular behaviors including proliferation, migration, apoptosis, and differentiation, each of which is regulated both spatially and temporally. Live imaging of developing embryos provides an essential tool to investigate these coordinated processes in three-dimensional space over time. For this purpose, the development and application of genetically encoded fluorescent protein (FP) reporters has accelerated over the past decade allowing for the high-resolution visualization of developmental progression. Ongoing efforts are aimed at generating improved reporters, where spectrally distinct as well as novel FPs whose optical properties can be photomodulated, are exploited for live imaging of mouse embryos. Moreover, subcellular tags in combination with using FPs allow for the visualization of multiple subcellular characteristics, such as cell position and cell morphology, in living embryos. Here, we review recent advances in the application of FPs for live imaging in the early mouse embryo, as well as some of the methods used for ex utero embryo development that facilitate on-stage time-lapse specimen visualization.
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27
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Zhang JX, Li H, Chan CF, Lan R, Chan WL, Law GL, Wong WK, Wong KL. A potential water-soluble ytterbium-based porphyrin–cyclen dual bio-probe for Golgi apparatus imaging and photodynamic therapy. Chem Commun (Camb) 2012; 48:9646-8. [DOI: 10.1039/c2cc34963a] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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28
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Snippert HJ, Schepers AG, Delconte G, Siersema PD, Clevers H. Slide preparation for single-cell-resolution imaging of fluorescent proteins in their three-dimensional near-native environment. Nat Protoc 2011; 6:1221-8. [PMID: 21799490 DOI: 10.1038/nprot.2011.365] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In recent years, many mouse models have been developed to mark and trace the fate of adult cell populations using fluorescent proteins. High-resolution visualization of such fluorescent markers in their physiological setting is thus an important aspect of adult stem cell research. Here we describe a protocol to produce sections (150-200 μm) of near-native tissue with optimal tissue and cellular morphology by avoiding artifacts inherent in standard freezing or embedding procedures. The activity of genetically expressed fluorescent proteins is maintained, thereby enabling high-resolution three-dimensional (3D) reconstructions of fluorescent structures in virtually all types of tissues. The procedure allows immunofluorescence labeling of proteins to depths up to 50 μm, as well as a chemical 'Click-iT' reaction to detect DNA-intercalating analogs such as ethynyl deoxyuridine (EdU). Generation of near-native sections ready for imaging analysis takes approximately 2-3 h. Postsectioning processes, such as antibody labeling or EdU detection, take up to 10 h.
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Affiliation(s)
- Hugo J Snippert
- Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands
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29
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Dhaliwal J, Lagace DC. Visualization and genetic manipulation of adult neurogenesis using transgenic mice. Eur J Neurosci 2011; 33:1025-36. [PMID: 21395845 DOI: 10.1111/j.1460-9568.2011.07600.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Many laboratories have focused efforts on the creation of transgenic mouse models to study adult neurogenesis. In the last decade several constitutive reporter, as well as inducible transgenic lines have been published that allowed for visualization, tracking and alteration of specific neurogenic cell populations in the adult brain. Given the popularity of this approach, multiple mouse lines are available, and this review summarizes the differences in the basic techniques that have been used to create these mice, highlighting the different constructs and reporter proteins used, as well as the strengths and limitations of each of these models. Representative examples from the literature demonstrate some of the diverse and seminal findings that have come to fruition through the laborious, yet highly rewarding work of creating transgenic mouse lines for adult neurogenesis research.
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Affiliation(s)
- Jagroop Dhaliwal
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
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30
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Khairy K, Keller PJ. Reconstructing embryonic development. Genesis 2011; 49:488-513. [DOI: 10.1002/dvg.20698] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 11/22/2010] [Accepted: 11/24/2010] [Indexed: 01/22/2023]
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31
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Artus J, Hadjantonakis AK. Generation of chimeras by aggregation of embryonic stem cells with diploid or tetraploid mouse embryos. Methods Mol Biol 2011; 693:37-56. [PMID: 21080273 DOI: 10.1007/978-1-60761-974-1_3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
From the hybrid creatures of the Greek and Egyptian mythologies, the concept of the chimera has evolved and, in modern day biology, refers to an organism comprises of at least two populations of genetically distinct cells. Mouse chimeras have proven an invaluable tool for the generation of genetically modified strains. In addition, chimeras have been extensively used in developmental biology as a powerful tool to analyze the phenotype of specific mutations, to attribute function to gene products and to address the question of cell autonomy versus noncell autonomy of gene function. This chapter describes a simple and economical technique used to generate mouse chimeras by embryo aggregation. Multiple aggregation combinations are described each of which can be tailored to answer particular biological questions.
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Affiliation(s)
- Jérôme Artus
- Developmental Biology Program, Sloan-Kettering Institute, New York, NY, USA
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32
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Abstract
Cell culture in two dimensions has been routinely and diligently undertaken in thousands of laboratories worldwide for the past four decades. However, the culture of cells in two dimensions is arguably primitive and does not reproduce the anatomy or physiology of a tissue for informative or useful study. Creating a third dimension for cell culture is clearly more relevant, but requires a multidisciplinary approach and multidisciplinary expertise. When entering the third dimension, investigators need to consider the design of scaffolds for supporting the organisation of cells or the use of bioreactors for controlling nutrient and waste product exchange. As 3D culture systems become more mature and relevant to human and animal physiology, the ability to design and develop co-cultures becomes possible as does the ability to integrate stem cells. The primary objectives for developing 3D cell culture systems vary widely - and range from engineering tissues for clinical delivery through to the development of models for drug screening. The intention of this review is to provide a general overview of the common approaches and techniques for designing 3D culture models.
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Affiliation(s)
- John W Haycock
- Department of Materials Science and Engineering, Kroto Research Institute, University of Sheffield, Sheffield, UK.
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33
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Abstract
Mouse genetic approaches when combined with live imaging tools have the potential to revolutionize our current understanding of mammalian biology. The availability and improvement of a wide variety of fluorescent proteins have provided indispensable tools to visualize cells in living organisms. It is now possible to generate genetically modified mouse strains expressing fluorescent proteins in a tissue-specific manner. These reporter-expressing strains make it possible to image dynamic cell behaviors in the context of a living embryo. Since mouse embryos develop within the uterus, live imaging experiments require culture conditions that closely mimic those in vivo. Over the past few decades, significant advances have been made in developing conditions for culturing both pre- and postimplantation stage embryos. In this chapter, we will discuss methods for ex utero culture of preimplantation and postimplantation stage mouse embryos. In particular, we will describe protocols for collecting embryos at various stages, setting up culture conditions for imaging and using laser scanning confocal microscopy to visualize live processes in mouse embryos expressing fluorescent reporters.
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Affiliation(s)
- Anna Piliszek
- Developmental Biology Program, Sloan-Kettering Institute, New York, NY, USA.
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34
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Balic A, Aguila HL, Mina M. Identification of cells at early and late stages of polarization during odontoblast differentiation using pOBCol3.6GFP and pOBCol2.3GFP transgenic mice. Bone 2010; 47:948-58. [PMID: 20728593 PMCID: PMC2957651 DOI: 10.1016/j.bone.2010.08.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 08/12/2010] [Accepted: 08/13/2010] [Indexed: 02/09/2023]
Abstract
Transgenic mouse lines in which GFP expression is under the control of tissue- and stage specific promoters have provided powerful experimental tools for identification and isolation of cells at specific stage of differentiation along a lineage. In the present study, we used primary cell cultures derived from the dental pulp from pOBCol3.6GFP and pOBCol2.3GFP transgenic mice as a model to develop markers for early stages of odontoblast differentiation from progenitor cells. We analyzed the temporal and spatial expression of 2.3-GFP and 3.6-GFP during in vitro mineralization. Using FACS to separate cells based on GFP expression, we obtained relatively homogenous subpopulations of cells and analyzed their dentinogenic potentials and their progression into odontoblasts. Our observations showed that these transgenes were activated before the onset of matrix deposition and in cells at different stages of polarization. The 3.6-GFP transgene was activated in cells in early stages of polarization, whereas the 2.3-GFP transgene was activated at a later stage of polarization just before or at the time of formation of secretory odontoblast.
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Affiliation(s)
- Anamaria Balic
- Department of Craniofacial Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT
| | - H. Leonardo Aguila
- Department of Immunology, School of Medicine, University of Connecticut Health Center, Farmington, CT
| | - Mina Mina
- Department of Craniofacial Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT
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35
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Nel-Themaat L, Jang CW, Stewart MD, Akiyama H, Viger RS, Behringer RR. Sertoli cell behaviors in developing testis cords and postnatal seminiferous tubules of the mouse. Biol Reprod 2010; 84:342-50. [PMID: 20944081 DOI: 10.1095/biolreprod.110.086900] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Sertoli cells are the primary structural component of the fetal testis cords and postnatal seminiferous tubules. Live imaging technologies facilitate the visualization of cell morphologies and behaviors through developmental processes. A transgenic mouse line was generated using a fragment of the rat Gata4 gene to direct the expression of a dual-color fluorescent protein reporter in fetal and adult Sertoli cells. The reporter encoded a red fluorescent protein, monomeric Cherry (mCherry), fused to histone 2B and enhanced green fluorescent protein (EGFP) fused to a glycosylphosphatidylinositol sequence, with a self-cleaving 2A polypeptide separating the two fusion proteins. After translation, the red and green fluorescent proteins translocated to the nucleus and plasma membrane, respectively, of Sertoli cells. Transgene expression in testes was first detected by fluorescent microscopy around Embryonic Day 12.0. Sertoli cell division and migration were visualized during testis cord formation in organ culture. Initially, the Sertoli cells had mesenchyme-like morphologies and behaviors, but later, the cells migrated to the periphery of the testis cords to become epithelialized. In postnatal seminiferous tubules, Sertoli nuclei were evenly spaced when viewed from the external surface of tubules, and Sertoli cytoplasm and membranes were associated with germ cells basally in a rosette pattern. This mouse line was bred to previously described transgenic mouse lines expressing EGFP in Sertoli cytoplasm or a nuclear cyan fluorescent protein (Cerulean) and mCherry in plasma membranes of germ cells. This revealed the physical relationship between Sertoli and germ cells in developing testis cords and provided a novel perspective on Sertoli cell development.
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Affiliation(s)
- Liesl Nel-Themaat
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, Texas, 77005, USA
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36
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Abstract
Fluorescence microscopy has profoundly changed cell and molecular biology studies by permitting tagged gene products to be followed as they function and interact. The ability of a fluorescent dye to absorb and emit light of different wavelengths allows it to generate startling contrast that, in the best cases, can permit single molecule detection and tracking. However, in many experimental settings, fluorescent probes fall short of their potential due to dye bleaching, dye signal saturation, and tissue autofluorescence. Here, we demonstrate that second harmonic generating (SHG) nanoprobes can be used for in vivo imaging, circumventing many of the limitations of classical fluorescence probes. Under intense illumination, such as at the focus of a laser-scanning microscope, these SHG nanocrystals convert two photons into one photon of half the wavelength; thus, when imaged by conventional two-photon microscopy, SHG nanoprobes appear to generate a signal with an inverse Stokes shift like a fluorescent dye, but with a narrower emission. Unlike commonly used fluorescent probes, SHG nanoprobes neither bleach nor blink, and the signal they generate does not saturate with increasing illumination intensity. The resulting contrast and detectability of SHG nanoprobes provide unique advantages for molecular imaging of living cells and tissues.
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37
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Abstract
Heterotopic ossification (HO), or endochondral bone formation at nonskeletal sites, often results from traumatic injury and can lead to devastating consequences. Alternatively, the ability to harness this phenomenon would greatly enhance current orthopedic tools for treating segmental bone defects. Thus, understanding the earliest events in this process potentially would allow us to design more targeted therapies to either block or enhance this process. Using a murine model of HO induced by delivery of adenovirus-transduced cells expressing bone morphogenetic protein 2 (BMP-2), we show here that one of the earliest stages in this process is the establishment of new vessels prior to the appearance of cartilage. As early as 48 hours after induction of HO, we observed the appearance of brown adipocytes expressing vascular endothelial growth factors (VEGFs) simultaneous with endothelial progenitor replication. This was determined by using a murine model that possesses the VEGF receptor 2 (Flk1) promoter containing an endothelial cell enhancer driving the expression of nuclear-localized yellow fluorescent protein (YFP). Expression of this marker has been shown previously to correlate with the establishment of new vasculature, and the nuclear localization of YFP expression allowed us to quantify changes in endothelial cell numbers. We found a significant increase in Flk1-H2B::YFP cells in BMP-2-treated animals compared with controls. The increase in endothelial progenitors occurred 3 days prior to the appearance of early cartilage. The data collectively suggest that vascular remodeling and growth may be essential to modify the microenvironment and enable engraftment of the necessary progenitors to form endochondral bone.
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38
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Stewart MD, Jang CW, Hong NW, Austin AP, Behringer RR. Dual fluorescent protein reporters for studying cell behaviors in vivo. Genesis 2010; 47:708-17. [PMID: 19813259 DOI: 10.1002/dvg.20565] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Fluorescent proteins (FPs) are useful tools for visualizing live cells and their behaviors. Protein domains that mediate subcellular localization have been fused to FPs to highlight cellular structures. FPs fused with histone H2B incorporate into chromatin allowing visualization of nuclear events. FPs fused to a glycosylphosphatidylinositol anchor signal sequence label the plasma membrane, highlighting cellular shape. Thus, a reporter gene containing both types of FP fusions would allow for effective monitoring of cell shape, movement, mitotic stage, apoptosis, and other cellular activities. Here, we report a binary color-coding system using four differently colored FP reporters that generates 16 distinct color codes to label the nuclei and plasma membranes of live cells in culture and in transgenic mice. As an initial test of this system in vivo, the promoter of the human Ubiquitin C (UBC) gene was used to widely express one of the color-code reporters. Widespread expression of the reporter was attained in embryos; however, both male and female transgenic mice were infertile. In contrast, the promoter of the mouse Oct4/Pou5f1 gene linked to two different color-code reporters specifically labeled blastocysts, primordial germ cells, and postnatal germ cells, and these mice were fertile. Time-lapse movies of fluorescently-labeled primordial germs cells demonstrate the utility of the color-code system to visualize cell behaviors. This set of new FP reporters should be a useful tool for labeling distinct cell populations and studying their behaviors in complex tissues in vivo.
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Affiliation(s)
- M David Stewart
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA
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Koentgen F, Suess G, Naf D. Engineering the mouse genome to model human disease for drug discovery. Methods Mol Biol 2010; 602:55-77. [PMID: 20012392 DOI: 10.1007/978-1-60761-058-8_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Genetically engineered mice (GEM) have become invaluable tools for human disease modeling and drug development. Completion of the mouse genome sequence in combination with transgenesis and gene targeting in embryonal stem cells have opened up unprecedented opportunities. Advanced technologies for derivation of GEM models will be introduced and discussed.
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Nowotschin S, Ferrer-Vaquer A, Hadjantonakis AK. Imaging mouse development with confocal time-lapse microscopy. Methods Enzymol 2010; 476:351-77. [PMID: 20691876 DOI: 10.1016/s0076-6879(10)76020-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The gene expression, signaling, and cellular dynamics driving mouse embryo development have emerged through embryology and genetic studies. However, since mouse development is a temporally regulated three-dimensional process, any insight needs to be placed in this context of real-time visualization. Live imaging using genetically encoded fluorescent protein reporters is pushing the envelope of our understanding by uncovering unprecedented insights into mouse development and leading to the formulation of quantitative accurate models.
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Affiliation(s)
- Sonja Nowotschin
- Developmental Biology Program, Sloan-Kettering Institute, New York, USA
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41
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Abstract
For the past three decades, methods for culturing mouse embryos ex vivo have been optimized in order to improve embryo viability and physiology throughout critical stages of embryogenesis. Combining advances made in the production of transgenic animals and in the development of different varieties of fluorescent proteins (FPs), time-lapse imaging is becoming more and more popular in the analysis of dynamic events during mouse development. Targeting FPs to specific cell types or subcellular compartments has enabled researchers to study cell proliferation, apoptosis, migration, and changes in cell morphology in living mouse embryos in real time. Here we provide a guide for time-lapse imaging of early stages of mouse embryo development.
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Affiliation(s)
- Ryan S Udan
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA
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Baril P, Martin-Duque P, Vassaux G. Visualization of gene expression in the live subject using the Na/I symporter as a reporter gene: applications in biotherapy. Br J Pharmacol 2009; 159:761-71. [PMID: 19814733 DOI: 10.1111/j.1476-5381.2009.00412.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Biotherapies involve the utilization of antibodies, genetically modified viruses, bacteria or cells for therapeutic purposes. Molecular imaging has the potential to provide unique information that will guarantee their biosafety in humans and provide a rationale for the future development of new generations of reagents. In this context, non-invasive imaging of gene expression is an attractive prospect, allowing precise, spacio-temporal measurements of gene expression in longitudinal studies involving gene transfer vectors. With the emergence of cell therapies in regenerative medicine, it is also possible to track cells injected into subjects. In this context, the Na/I symporter (NIS) has been used in preclinical studies. Associated with a relevant radiotracer ((123)I(-), (124)I(-), (99m)TcO4(-)), NIS can be used to monitor gene transfer and the spread of selectively replicative viruses in tumours as well as in cells with a therapeutic potential. In addition to its imaging potential, NIS can be used as a therapeutic transgene through its ability to concentrate therapeutic doses of radionuclides in target cells. This dual property has applications in cancer treatment and could also be used to eradicate cells with therapeutic potential in the case of adverse events. Through experience acquired in preclinical studies, we can expect that non-invasive molecular imaging using NIS as a transgene will be pivotal for monitoring in vivo the exact distribution and pharmacodynamics of gene expression in a precise and quantitative way. This review highlights the applications of NIS in biotherapy, with a particular emphasis on image-guided radiotherapy, monitoring of gene and vector biodistribution and trafficking of stem cells.
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Affiliation(s)
- Patrick Baril
- Inserm U948, Université de Nantes, Nantes Atlantique Universités, EA4274, Institut des Maladies de l'Appareil Digestif, CHU Hôtel Dieu, Nantes, France.
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Day RN, Davidson MW. The fluorescent protein palette: tools for cellular imaging. Chem Soc Rev 2009; 38:2887-921. [PMID: 19771335 DOI: 10.1039/b901966a] [Citation(s) in RCA: 561] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
This critical review provides an overview of the continually expanding family of fluorescent proteins (FPs) that have become essential tools for studies of cell biology and physiology. Here, we describe the characteristics of the genetically encoded fluorescent markers that now span the visible spectrum from deep blue to deep red. We identify some of the novel FPs that have unusual characteristics that make them useful reporters of the dynamic behaviors of proteins inside cells, and describe how many different optical methods can be combined with the FPs to provide quantitative measurements in living systems (227 references).
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Affiliation(s)
- Richard N Day
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Dr., Indianapolis, IN 46202, USA.
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Nowotschin S, Eakin GS, Hadjantonakis AK. Dual transgene strategy for live visualization of chromatin and plasma membrane dynamics in murine embryonic stem cells and embryonic tissues. Genesis 2009; 47:330-6. [PMID: 19358158 PMCID: PMC2875877 DOI: 10.1002/dvg.20500] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To simultaneously follow multiple subcellular characteristics, for example, cell position and cell morphology, in living specimens requires multiple subcellular labels. Toward this goal, we generated dual-tagged mouse embryonic stem (ES) cells constitutively expressing differentially localized, spectrally distinct, genetically encoded fluorescent protein fusions. We have used human histone H2B fusions to fluorescent proteins to mark chromatin. This provides a descriptor of cell position, division, and death. An additional descriptor of cell morphology is achieved by combining this transgene with select lipid-modified fluorescent protein fusions that mark the plasma membrane. Using this strategy, wewere able to live image cellular dynamics in three dimensions over time both in cultured ES cells and in mouse embryos generated using dual-tagged ES cells. This study, therefore, presents the feasibility of applying multiple spectrally and subcellularly distinct fluorescent protein reporters for live imaging studies in ES cells and mouse embryos. Furthermore, the increasing availability of spectral variant fluorescent proteins along with the development of methods that permit improved spectral separation now facilitate multiplexing of fluorescent reporters to provide readouts of a variety of anatomical and physiological behaviors simultaneously in living specimens.
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Affiliation(s)
- Sonja Nowotschin
- Developmental Biology Program, Sloan-Kettering Institute, New York, New York
| | - Guy S. Eakin
- Developmental Biology Program, Sloan-Kettering Institute, New York, New York
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Larina IV, Shen W, Kelly OG, Hadjantonakis AK, Baron MH, Dickinson ME. A membrane associated mCherry fluorescent reporter line for studying vascular remodeling and cardiac function during murine embryonic development. Anat Rec (Hoboken) 2009; 292:333-41. [PMID: 19248165 PMCID: PMC2901876 DOI: 10.1002/ar.20821] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The development of the cardiovascular system is a highly dynamic process dependent on multiple signaling pathways regulating proliferation, differentiation, migration, cell-cell and cell-matrix interactions. To characterize cell and tissue dynamics during the formation of the cardiovascular system in mice, we generated a novel transgenic mouse line, Tg(Flk1::myr-mCherry), in which endothelial cell membranes are brightly labeled with mCherry, a red fluorescent protein. Tg(Flk1::myr-mCherry) mice are viable, fertile, and do not exhibit any developmental abnormalities. High levels of mCherry are expressed in the embryonic endothelium and endocardium, and expression is also observed in capillaries in adult animals. Targeting of the fluorescent protein to the cell membrane allows for subcellular imaging and cell tracking. By acquiring confocal time lapses of live embryos cultured on the microscope stage, we demonstrate that the newly generated transgenic model beautifully highlights the sprouting behaviors of endothelial cells during vascular plexus formation. We have also used embryos from this line to imaging the endocardium in the beating embryonic mouse heart, showing that Tg(Flk1::myr-mCherry) mice are suitable for the characterization of cardio dynamics. Furthermore, when combined with the previously described Tg(Flk1::H2B-EYFP) line, cell number in addition to cell architecture is revealed, making it possible to determine how individual endothelial cells contribute to the structure of the vessel.
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Affiliation(s)
- Irina V. Larina
- Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Wei Shen
- Biological Imaging Center, Caltech, Pasadena, CA 91125
| | - Olivia G. Kelly
- Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Biological Imaging Center, Caltech, Pasadena, CA 91125
| | | | - Margaret H. Baron
- Depts of Medicine, Oncological Sciences, Gene and Cell Medicine and Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029
| | - Mary E. Dickinson
- Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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Molitoris BA, Sandoval RM. Techniques to study nephron function: microscopy and imaging. Pflugers Arch 2009; 458:203-9. [PMID: 19145447 DOI: 10.1007/s00424-008-0629-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 12/23/2008] [Indexed: 11/26/2022]
Abstract
Recent advances in optics, computer sciences, fluorophores, and molecular techniques allow investigators the opportunity to study dynamic events within the functioning kidney with subcellular resolution. Investigators can now use two-photon microscopy to follow several complex heterogenous processes in organs such as the kidney with high spacial and temporal resolution. Repeat determinations over time within the same animal are possible and minimize animal use and interanimal variability. Furthermore, the ability to obtain volumetric data (3D) makes quantitative 4D (time) analysis possible. Finally, use of multiple fluorophores concurrently allows for three different or interactive processes to be observed simultaneously. Therefore, this approach compliments existing molecular, biochemical, and pharmacologic techniques by advancing in vivo data analysis and interpretation to subcellular levels for molecules without the requirement for fixation. Its use in the kidney is in its infancy but offers much promise for unraveling the complex interdependent physiologic and pathophysiologic processes known to contribute to cell function and disease.
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Affiliation(s)
- Bruce A Molitoris
- Department of Medicine, Indiana University School of Medicine, Indianapolis, 46202, USA.
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Kwon GS, Viotti M, Hadjantonakis AK. The endoderm of the mouse embryo arises by dynamic widespread intercalation of embryonic and extraembryonic lineages. Dev Cell 2008; 15:509-20. [PMID: 18854136 DOI: 10.1016/j.devcel.2008.07.017] [Citation(s) in RCA: 309] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 07/10/2008] [Accepted: 07/30/2008] [Indexed: 12/22/2022]
Abstract
The cell movements underlying the morphogenesis of the embryonic endoderm, the tissue that will give rise to the respiratory and digestive tracts, are complex and not well understood. Using live imaging combined with genetic labeling, we investigated the cell behaviors and fate of the visceral endoderm during gut endoderm formation in the mouse gastrula. Contrary to the prevailing view, our data reveal no mass displacement of visceral endoderm to extraembryonic regions concomitant with the emergence of epiblast-derived definitive endoderm. Instead, we observed dispersal of the visceral endoderm epithelium and extensive mixing between cells of visceral endoderm and epiblast origin. Visceral endoderm cells remained associated with the epiblast and were incorporated into the early gut tube. Our findings suggest that the segregation of extraembryonic and embryonic tissues within the mammalian embryo is not as strict as believed and that a lineage previously defined as exclusively extraembryonic contributes cells to the embryo.
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Affiliation(s)
- Gloria S Kwon
- Developmental Biology Program, Sloan-Kettering Institute, 1275 York Avenue, New York, NY 10021, USA
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Akins EJ, Dubey P. Noninvasive imaging of cell-mediated therapy for treatment of cancer. J Nucl Med 2008; 49 Suppl 2:180S-95S. [PMID: 18523073 DOI: 10.2967/jnumed.107.045971] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cell-mediated therapy (immunotherapy) for the treatment of cancer is an active area of investigation in animal models and clinical trials. Despite many advances, objective responses to immunotherapy are observed in a small number of cases, for certain tumor types. To better understand differences in outcomes, it is critical to develop assays for tracking effector cell localization and function in situ. The fairly recent use of molecular imaging techniques to track cell populations has presented researchers and clinicians with a powerful diagnostic tool for determining the efficacy of cell-mediated therapy for the treatment of cancer. This review highlights the application of whole-body noninvasive radioisotopic, magnetic, and optical imaging methods for monitoring effector cells in vivo. Issues that affect sensitivity of detection, such as methods of cell marking, efficiency of cell labeling, toxicity, and limits of detection of imaging modalities, are discussed.
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Affiliation(s)
- Elizabeth J Akins
- Section on Molecular Medicine, Department of Internal Medicine, Wake Forest University Health Sciences, Winston-Salem, North Carolina, USA
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Kieffer BL, Evans CJ. Opioid receptors: from binding sites to visible molecules in vivo. Neuropharmacology 2008; 56 Suppl 1:205-12. [PMID: 18718480 DOI: 10.1016/j.neuropharm.2008.07.033] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 07/24/2008] [Indexed: 12/16/2022]
Abstract
Opioid drugs such as heroin interact directly with opioid receptors whilst other addictive drugs, including marijuana, alcohol and nicotine indirectly activate endogenous opioid systems to contribute to their rewarding properties. The opioid system therefore plays a key role in addiction neurobiology and continues to be a primary focus for NIDA-supported research. Opioid receptors and their peptide ligands, the endorphins and enkephalins, form an extensive heterogeneous network throughout the central and peripheral nervous system. In addition to reward, opioid drugs regulate many functions such that opioid receptors are targets of choice in several physiological, neurological and psychiatric disorders. Because of the multiplicity and diversity of ligands and receptors, opioid receptors have served as an optimal model for G protein coupled receptor (GPCR) research. The isolation of opioid receptor genes opened the way to molecular manipulations of the receptors, both in artificial systems and in vivo, contributing to our current understanding of the diversity of opioid receptor biology at the behavioral, cellular and molecular levels. This review will briefly summarize some aspects of current knowledge that has accumulated since the very early characterization of opioid receptor genes. Importantly, we will identify a number of research directions that are likely to develop during the next decade.
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Affiliation(s)
- Brigitte L Kieffer
- IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), Département Neurobiologie et génétique, Illkirch, F-67400 France; INSERM, U596, Illkirch F-67400, France; CNRS, UMR7104, Illkirch F-67400, France.
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Hadjantonakis AK, Pisano E, Papaioannou VE. Tbx6 regulates left/right patterning in mouse embryos through effects on nodal cilia and perinodal signaling. PLoS One 2008; 3:e2511. [PMID: 18575602 PMCID: PMC2427182 DOI: 10.1371/journal.pone.0002511] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Accepted: 05/24/2008] [Indexed: 01/14/2023] Open
Abstract
Background The determination of left/right body axis during early embryogenesis sets up a developmental cascade that coordinates the development of the viscera and is essential to the correct placement and alignment of organ systems and vasculature. Defective left-right patterning can lead to congenital cardiac malformations, vascular anomalies and other serious health problems. Here we describe a novel role for the T-box transcription factor gene Tbx6 in left/right body axis determination in the mouse. Results Embryos lacking Tbx6 show randomized embryo turning and heart looping. Our results point to multiple mechanisms for this effect. First, Dll1, a direct target of Tbx6, is down regulated around the node in Tbx6 mutants and there is a subsequent decrease in nodal signaling, which is required for laterality determination. Secondly, in spite of a lack of expression of Tbx6 in the node, we document a profound effect of the Tbx6 mutation on the morphology and motility of nodal cilia. This results in the loss of asymmetric calcium signaling at the periphery of the node, suggesting that unidirectional nodal flow is disrupted. To carry out these studies, we devised a novel method for direct labeling and live imaging cilia in vivo using a genetically-encoded fluorescent protein fusion that labels tubulin, combined with laser point scanning confocal microscopy for direct visualization of cilia movement. Conclusions We conclude that the transcription factor gene Tbx6 is essential for correct left/right axis determination in the mouse and acts through effects on notch signaling around the node as well as through an effect on the morphology and motility of the nodal cilia.
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Affiliation(s)
| | - Elinor Pisano
- Department of Genetics and Development, College of Physicians and Surgeons of Columbia University, New York, New York, United States of America
| | - Virginia E. Papaioannou
- Department of Genetics and Development, College of Physicians and Surgeons of Columbia University, New York, New York, United States of America
- * E-mail:
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