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Spikol ED, Cheng J, Macurak M, Subedi A, Halpern ME. Genetically defined nucleus incertus neurons differ in connectivity and function. eLife 2024; 12:RP89516. [PMID: 38819436 PMCID: PMC11142643 DOI: 10.7554/elife.89516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024] Open
Abstract
The nucleus incertus (NI), a conserved hindbrain structure implicated in the stress response, arousal, and memory, is a major site for production of the neuropeptide relaxin-3. On the basis of goosecoid homeobox 2 (gsc2) expression, we identified a neuronal cluster that lies adjacent to relaxin 3a (rln3a) neurons in the zebrafish analogue of the NI. To delineate the characteristics of the gsc2 and rln3a NI neurons, we used CRISPR/Cas9 targeted integration to drive gene expression specifically in each neuronal group, and found that they differ in their efferent and afferent connectivity, spontaneous activity, and functional properties. gsc2 and rln3a NI neurons have widely divergent projection patterns and innervate distinct subregions of the midbrain interpeduncular nucleus (IPN). Whereas gsc2 neurons are activated more robustly by electric shock, rln3a neurons exhibit spontaneous fluctuations in calcium signaling and regulate locomotor activity. Our findings define heterogeneous neurons in the NI and provide new tools to probe its diverse functions.
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Affiliation(s)
- Emma D Spikol
- Department of Molecular and Systems Biology, Geisel School of Medicine at DartmouthHanoverUnited States
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Ji Cheng
- Department of Molecular and Systems Biology, Geisel School of Medicine at DartmouthHanoverUnited States
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Michelle Macurak
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Abhignya Subedi
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
| | - Marnie E Halpern
- Department of Molecular and Systems Biology, Geisel School of Medicine at DartmouthHanoverUnited States
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
- Department of Biology, Johns Hopkins UniversityBaltimoreUnited States
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2
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Rich MH, Sharrock AV, Mulligan TS, Matthews F, Brown AS, Lee-Harwood HR, Williams EM, Copp JN, Little RF, Francis JJB, Horvat CN, Stevenson LJ, Owen JG, Saxena MT, Mumm JS, Ackerley DF. A metagenomic library cloning strategy that promotes high-level expression of captured genes to enable efficient functional screening. Cell Chem Biol 2023; 30:1680-1691.e6. [PMID: 37898120 PMCID: PMC10842177 DOI: 10.1016/j.chembiol.2023.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 06/17/2023] [Accepted: 10/02/2023] [Indexed: 10/30/2023]
Abstract
Functional screening of environmental DNA (eDNA) libraries is a potentially powerful approach to discover enzymatic "unknown unknowns", but is usually heavily biased toward the tiny subset of genes preferentially transcribed and translated by the screening strain. We have overcome this by preparing an eDNA library via partial digest with restriction enzyme FatI (cuts CATG), causing a substantial proportion of ATG start codons to be precisely aligned with strong plasmid-encoded promoter and ribosome-binding sequences. Whereas we were unable to select nitroreductases from standard metagenome libraries, our FatI strategy yielded 21 nitroreductases spanning eight different enzyme families, each conferring resistance to the nitro-antibiotic niclosamide and sensitivity to the nitro-prodrug metronidazole. We showed expression could be improved by co-expressing rare tRNAs and encoded proteins purified directly using an embedded His6-tag. In a transgenic zebrafish model of metronidazole-mediated targeted cell ablation, our lead MhqN-family nitroreductase proved ∼5-fold more effective than the canonical nitroreductase NfsB.
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Affiliation(s)
- Michelle H Rich
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Abigail V Sharrock
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Timothy S Mulligan
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Frazer Matthews
- Department of Genetic Medicine, McKusick-Nathans Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Alistair S Brown
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Hannah R Lee-Harwood
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Elsie M Williams
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Janine N Copp
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Rory F Little
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Jenni J B Francis
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Claire N Horvat
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Luke J Stevenson
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Jeremy G Owen
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Meera T Saxena
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Jeff S Mumm
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Genetic Medicine, McKusick-Nathans Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Center for Nanomedicine, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - David F Ackerley
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand.
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3
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Coomer C, Naumova D, Talay M, Zolyomi B, Snell N, Sorkac A, Chanchu JM, Cheng J, Roman I, Li J, Robson D, Barnea G, Halpern ME. Transsynaptic labeling and transcriptional control of zebrafish neural circuits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.03.535421. [PMID: 37066422 PMCID: PMC10103993 DOI: 10.1101/2023.04.03.535421] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
Deciphering the connectome, the ensemble of synaptic connections that underlie brain function is a central goal of neuroscience research. The trans-Tango genetic approach, initially developed for anterograde transsynaptic tracing in Drosophila, can be used to map connections between presynaptic and postsynaptic partners and to drive gene expression in target neurons. Here, we describe the successful adaptation of trans-Tango to visualize neural connections in a living vertebrate nervous system, that of the zebrafish. Connections were validated between synaptic partners in the larval retina and brain. Results were corroborated by functional experiments in which optogenetic activation of retinal ganglion cells elicited responses in neurons of the optic tectum, as measured by trans-Tango-dependent expression of a genetically encoded calcium indicator. Transsynaptic signaling through trans-Tango reveals predicted as well as previously undescribed synaptic connections, providing a valuable in vivo tool to monitor and interrogate neural circuits over time.
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4
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Rich MH, Sharrock AV, Mulligan TS, Matthews F, Brown AS, Lee-Harwood HR, Williams EM, Copp JN, Little RF, Francis JJB, Horvat CN, Stevenson LJ, Owen JG, Saxena MT, Mumm JS, Ackerley DF. A metagenomic library cloning strategy that promotes high-level expression of captured genes to enable efficient functional screening. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.24.534183. [PMID: 36993673 PMCID: PMC10055417 DOI: 10.1101/2023.03.24.534183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Functional screening of environmental DNA (eDNA) libraries is a potentially powerful approach to discover enzymatic "unknown unknowns", but is usually heavily biased toward the tiny subset of genes preferentially transcribed and translated by the screening strain. We have overcome this by preparing an eDNA library via partial digest with restriction enzyme FatI (cuts CATG), causing a substantial proportion of ATG start codons to be precisely aligned with strong plasmid-encoded promoter and ribosome-binding sequences. Whereas we were unable to select nitroreductases from standard metagenome libraries, our FatI strategy yielded 21 nitroreductases spanning eight different enzyme families, each conferring resistance to the nitro-antibiotic niclosamide and sensitivity to the nitro-prodrug metronidazole. We showed expression could be improved by co-expressing rare tRNAs and encoded proteins purified directly using an embedded His6-tag. In a transgenic zebrafish model of metronidazole-mediated targeted cell ablation, our lead MhqN-family nitroreductase proved ~5-fold more effective than the canonical nitroreductase NfsB.
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Affiliation(s)
- Michelle H Rich
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Abigail V Sharrock
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Timothy S Mulligan
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Frazer Matthews
- Department of Genetic Medicine, McKusick-Nathans Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Alistair S Brown
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Hannah R Lee-Harwood
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Elsie M Williams
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
- Current address: Burnet Institute, Melbourne, Victoria 3004, Australia
| | - Janine N Copp
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
- Current addresses: Michael Smith Laboratories, University of British Columbia, Vancouver BC V6T 1Z4, Canada; Abcellera Biologics Inc, Vancouver BC V5Y 0A1, Canada
| | - Rory F Little
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
- Current address: Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, 07745 Jena, Germany
| | - Jenni JB Francis
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Claire N Horvat
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
- Current address: Teva Pharmaceuticals, Sydney, New South Wales 2113, Australia
| | - Luke J Stevenson
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Jeremy G Owen
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Meera T Saxena
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Jeff S Mumm
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Department of Genetic Medicine, McKusick-Nathans Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Center for Nanomedicine, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - David F Ackerley
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
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5
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Sharrock AV, Mulligan TS, Hall KR, Williams EM, White DT, Zhang L, Emmerich K, Matthews F, Nimmagadda S, Washington S, Le KD, Meir-Levi D, Cox OL, Saxena MT, Calof AL, Lopez-Burks ME, Lander AD, Ding D, Ji H, Ackerley DF, Mumm JS. NTR 2.0: a rationally engineered prodrug-converting enzyme with substantially enhanced efficacy for targeted cell ablation. Nat Methods 2022; 19:205-215. [PMID: 35132245 PMCID: PMC8851868 DOI: 10.1038/s41592-021-01364-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 11/29/2021] [Indexed: 11/12/2022]
Abstract
Transgenic expression of bacterial nitroreductase (NTR) enzymes sensitizes eukaryotic cells to prodrugs such as metronidazole (MTZ), enabling selective cell-ablation paradigms that have expanded studies of cell function and regeneration in vertebrates. However, first-generation NTRs required confoundingly toxic prodrug treatments to achieve effective cell ablation, and some cell types have proven resistant. Here we used rational engineering and cross-species screening to develop an NTR variant, NTR 2.0, which exhibits ~100-fold improvement in MTZ-mediated cell-specific ablation efficacy, eliminating the need for near-toxic prodrug treatment regimens. NTR 2.0 therefore enables sustained cell-loss paradigms and ablation of previously resistant cell types. These properties permit enhanced interrogations of cell function, extended challenges to the regenerative capacities of discrete stem cell niches, and novel modeling of chronic degenerative diseases. Accordingly, we have created a series of bipartite transgenic reporter/effector resources to facilitate dissemination of NTR 2.0 to the research community.
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Affiliation(s)
- Abigail V Sharrock
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Timothy S Mulligan
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Kelsi R Hall
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Elsie M Williams
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - David T White
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Liyun Zhang
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Kevin Emmerich
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Frazer Matthews
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Saumya Nimmagadda
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Selena Washington
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Katherine D Le
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Danielle Meir-Levi
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Olivia L Cox
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Meera T Saxena
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
- Luminomics, Baltimore, MD, USA
| | - Anne L Calof
- Department of Anatomy and Neurobiology, University of California, Irvine, CA, USA
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
- Center for Complex Biological Systems, University of California, Irvine, CA, USA
| | - Martha E Lopez-Burks
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
- Center for Complex Biological Systems, University of California, Irvine, CA, USA
| | - Arthur D Lander
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
- Center for Complex Biological Systems, University of California, Irvine, CA, USA
| | - Ding Ding
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Hongkai Ji
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - David F Ackerley
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand.
- Centre for Biodiscovery and Maurice Wilkins Centre for Molecular Biodiscovery, Victoria University of Wellington, Wellington, New Zealand.
| | - Jeff S Mumm
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA.
- The Center for Nanomedicine, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA.
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA.
- Department of Genetic Medicine, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, MD, USA.
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6
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Choi JH, Duboue ER, Macurak M, Chanchu JM, Halpern ME. Specialized neurons in the right habenula mediate response to aversive olfactory cues. eLife 2021; 10:e72345. [PMID: 34878403 PMCID: PMC8691842 DOI: 10.7554/elife.72345] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 12/07/2021] [Indexed: 12/27/2022] Open
Abstract
Hemispheric specializations are well studied at the functional level but less is known about the underlying neural mechanisms. We identified a small cluster of cholinergic neurons in the dorsal habenula (dHb) of zebrafish, defined by their expression of the lecithin retinol acyltransferase domain containing 2 a (lratd2a) gene and their efferent connections with a subregion of the ventral interpeduncular nucleus (vIPN). The lratd2a-expressing neurons in the right dHb are innervated by a subset of mitral cells from both the left and right olfactory bulb and are activated upon exposure to the odorant cadaverine that is repellent to adult zebrafish. Using an intersectional strategy to drive expression of the botulinum neurotoxin specifically in these neurons, we find that adults no longer show aversion to cadaverine. Mutants with left-isomerized dHb that lack these neurons are also less repelled by cadaverine and their behavioral response to alarm substance, a potent aversive cue, is diminished. However, mutants in which both dHb have right identity appear more reactive to alarm substance. The results implicate an asymmetric dHb-vIPN neural circuit in the processing of repulsive olfactory cues and in modulating the resultant behavioral response.
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Affiliation(s)
- Jung-Hwa Choi
- Carnegie Institution for Science, Department of EmbryologyBaltimoreUnited States
| | - Erik R Duboue
- Jupiter Life Science Initiative, Florida Atlantic UniversityJupiterUnited States
- Wilkes Honors College, Florida Atlantic UniversityJupiterUnited States
| | - Michelle Macurak
- Carnegie Institution for Science, Department of EmbryologyBaltimoreUnited States
| | - Jean-Michel Chanchu
- Carnegie Institution for Science, Department of EmbryologyBaltimoreUnited States
| | - Marnie E Halpern
- Carnegie Institution for Science, Department of EmbryologyBaltimoreUnited States
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7
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Namikawa K, Dorigo A, Zagrebelsky M, Russo G, Kirmann T, Fahr W, Dübel S, Korte M, Köster RW. Modeling Neurodegenerative Spinocerebellar Ataxia Type 13 in Zebrafish Using a Purkinje Neuron Specific Tunable Coexpression System. J Neurosci 2019; 39:3948-3969. [PMID: 30862666 PMCID: PMC6520513 DOI: 10.1523/jneurosci.1862-18.2019] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 02/19/2019] [Accepted: 02/25/2019] [Indexed: 12/17/2022] Open
Abstract
Purkinje cells (PCs) are primarily affected in neurodegenerative spinocerebellar ataxias (SCAs). For generating animal models for SCAs, genetic regulatory elements specifically targeting PCs are required, thereby linking pathological molecular effects with impaired function and organismic behavior. Because cerebellar anatomy and function are evolutionary conserved, zebrafish represent an excellent model to study SCAs in vivo We have isolated a 258 bp cross-species PC-specific enhancer element that can be used in a bidirectional manner for bioimaging of transgene-expressing PCs in zebrafish (both sexes) with variable copy numbers for tuning expression strength. Emerging ectopic expression at high copy numbers can be further eliminated by repurposing microRNA-mediated posttranslational mRNA regulation.Subsequently, we generated a transgenic SCA type 13 (SCA13) model, using a zebrafish-variant mimicking a human pathological SCA13R420H mutation, resulting in cell-autonomous progressive PC degeneration linked to cerebellum-driven eye-movement deficits as observed in SCA patients. This underscores that investigating PC-specific cerebellar neuropathologies in zebrafish allows for interconnecting bioimaging of disease mechanisms with behavioral analysis suitable for therapeutic compound testing.SIGNIFICANCE STATEMENT SCA13 patients carrying a KCNC3R420H allele have been shown to display mid-onset progressive cerebellar atrophy, but genetic modeling of SCA13 by expressing this pathogenic mutant in different animal models has not resulted in neuronal degeneration so far; likely because the transgene was expressed in heterologous cell types. We developed a genetic system for tunable PC-specific coexpression of several transgenes to manipulate and simultaneously monitor cerebellar PCs. We modeled a SCA13 zebrafish accessible for bioimaging to investigate disease progression, revealing robust PC degeneration, resulting in impaired eye movement. Our transgenic zebrafish mimicking both neuropathological and behavioral changes manifested in SCA-affected patients will be suitable for investigating causes of cerebellar diseases in vivo from the molecular to the behavioral level.
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Affiliation(s)
| | | | - Marta Zagrebelsky
- Cellular Neurobiology, Zoological Institute, Technical University Braunschweig, Braunschweig 38106, Germany
| | - Giulio Russo
- Cellular and Molecular Neurobiology
- Biotechnology and Bioinformatics, Institute for Biochemistry, Technical University Braunschweig 38106, Germany, and
| | | | - Wieland Fahr
- Biotechnology and Bioinformatics, Institute for Biochemistry, Technical University Braunschweig 38106, Germany, and
| | - Stefan Dübel
- Biotechnology and Bioinformatics, Institute for Biochemistry, Technical University Braunschweig 38106, Germany, and
| | - Martin Korte
- Cellular Neurobiology, Zoological Institute, Technical University Braunschweig, Braunschweig 38106, Germany
- Research Group Neuroinflammation and Neurodegeneration, Helmholtz Centre for Infection Research, Braunschweig 38106, Germany
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8
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Eisenhut P, Klanert G, Weinguny M, Baier L, Jadhav V, Ivansson D, Borth N. A CRISPR/Cas9 based engineering strategy for overexpression of multiple genes in Chinese hamster ovary cells. Metab Eng 2018; 48:72-81. [PMID: 29852271 DOI: 10.1016/j.ymben.2018.05.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/25/2018] [Accepted: 05/26/2018] [Indexed: 12/23/2022]
Abstract
Manipulation of multiple genes to engineer Chinese Hamster Ovary (CHO) cells for better performance in production processes of biopharmaceuticals has recently become more and more popular. Yet, identification of useful genes and the unequivocally assessment of their effect alone and in combination(s) on the cellular phenotype is difficult due to high variation between subclones. Here, we present development and proof-of-concept of a novel engineering strategy using multiplexable activation of artificially repressed genes (MAARGE). This strategy will allow faster screening of overexpression of multiple genes in all possible combinations. MAARGE, in its here presented installment, comprises four different genes of interest that can all be stably integrated into the genome from one plasmid in a single transfection. Three of the genes are initially repressed by a repressor element (RE) that is integrated between promoter and translation start site. We show that an elongated 5'-UTR with an additional transcription termination (poly(A)) signal most efficiently represses protein expression. Distinct guide RNA (gRNA) targets flanking the REs for each gene then allow to specifically delete the RE by CRISPR/Cas9 and thus to activate the expression of the corresponding gene(s). We show that both individual and multiplexed activation of the genes of interest in a stably transfected CHO cell line is possible. Also, upon transfection of this stable cell line with all three gRNAs together, it was possible to isolate cells that express all potential gene combinations in a single experiment.
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Key Words
- BFP, Blue Fluorescent Protein
- BP, Bandpass
- CD, Chemically defined
- CHO, Chinese Hamster ovary
- CRISPR, Clustered regularly interspaced palindromic repeats
- CRISPR/Cas9
- Cas9, CRISPR-associated protein 9
- Cell line engineering
- Chinese Hamster
- Fluorescent proteins
- GFP, Green Fluorescent Protein
- MAARGE, Multiplexable Activation of Artificially Repressed Genes
- MFI, Mean fluorescence intensity
- Ovary cells CHO
- Pathway engineering
- RE, Repressor element
- REST, Repressor element 1 silencing transcription factor
- RFP, Red Fluorescent protein
- RFP657, Red Fluorescent protein 657
- bp, Base pairs
- gRNA, Guide RNA
- poly(A), Poly Adenylation signal
- rpm, Rotations per minute
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Affiliation(s)
- Peter Eisenhut
- ACIB Gmbh, Austrian Centre of Industrial Biotechnology, Graz, Austria; Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Gerald Klanert
- ACIB Gmbh, Austrian Centre of Industrial Biotechnology, Graz, Austria; Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Marcus Weinguny
- ACIB Gmbh, Austrian Centre of Industrial Biotechnology, Graz, Austria; Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Laurenz Baier
- ACIB Gmbh, Austrian Centre of Industrial Biotechnology, Graz, Austria; Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Vaibhav Jadhav
- ACIB Gmbh, Austrian Centre of Industrial Biotechnology, Graz, Austria; Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | | | - Nicole Borth
- ACIB Gmbh, Austrian Centre of Industrial Biotechnology, Graz, Austria; Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria.
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9
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Sheahan AV, Ellis L. Epigenetic reprogramming: A key mechanism driving therapeutic resistance. Urol Oncol 2018; 36:375-379. [PMID: 29395951 DOI: 10.1016/j.urolonc.2017.12.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 12/21/2017] [Accepted: 12/24/2017] [Indexed: 01/08/2023]
Abstract
Prostate cancer initiation, development and progression is driven by androgen receptor (AR) signaling. Androgen deprivation therapy is the primary treatment for patients that present with locally advanced or metastatic disease. However, androgen deprivation therapy is not curative, and patients will progress to castrate-resistant disease (CRPC). Although most patient's progress to CRPC via restoration of AR signaling (CRPC-Ad), approximately a quarter of patients will progress via mechanisms independent of AR signaling. This highly lethal phenotype is termed aggressive variant prostate cancer (AVPC). Data from clinical and preclinical studies demonstrate that AVPC involves combinatorial loss-of-function mutations in key tumor suppressor genes, low to absent AR levels, and re-expression of reprogramming, stem, and neuroendocrine related gene signatures. Further, AVPC is shown to evolve from a CRPC-Ad phenotype. Overall, lineage plasticity underlying progression to AVPC is thought to be provoked by genome-wide chromatin remodeling. Here, we will discuss an emerging focus on key drivers of chromatin remodeling in AVPC, and how their identification could provide noninvasive biomarkers to predict or detect AVPC emergence, and therapeutic targets to prevent or reverse progression to AVPC.
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Affiliation(s)
- Anjali V Sheahan
- Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA
| | - Leigh Ellis
- Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA; Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; The Broad Institute, Cambridge, MA.
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10
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Lee DA, Andreev A, Truong TV, Chen A, Hill AJ, Oikonomou G, Pham U, Hong YK, Tran S, Glass L, Sapin V, Engle J, Fraser SE, Prober DA. Genetic and neuronal regulation of sleep by neuropeptide VF. eLife 2017; 6:25727. [PMID: 29106375 PMCID: PMC5705210 DOI: 10.7554/elife.25727] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 11/03/2017] [Indexed: 12/25/2022] Open
Abstract
Sleep is an essential and phylogenetically conserved behavioral state, but it remains unclear to what extent genes identified in invertebrates also regulate vertebrate sleep. RFamide-related neuropeptides have been shown to promote invertebrate sleep, and here we report that the vertebrate hypothalamic RFamide neuropeptide VF (NPVF) regulates sleep in the zebrafish, a diurnal vertebrate. We found that NPVF signaling and npvf-expressing neurons are both necessary and sufficient to promote sleep, that mature peptides derived from the NPVF preproprotein promote sleep in a synergistic manner, and that stimulation of npvf-expressing neurons induces neuronal activity levels consistent with normal sleep. These results identify NPVF signaling and npvf-expressing neurons as a novel vertebrate sleep-promoting system and suggest that RFamide neuropeptides participate in an ancient and central aspect of sleep control.
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Affiliation(s)
- Daniel A Lee
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Andrey Andreev
- Department of Bioengineering, University of Southern California, Los Angeles, United States
| | - Thai V Truong
- Translational Imaging Center, University of Southern California, Los Angeles, United States
| | - Audrey Chen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Andrew J Hill
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Grigorios Oikonomou
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Uyen Pham
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Young K Hong
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Steven Tran
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Laura Glass
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Viveca Sapin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Jae Engle
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Scott E Fraser
- Department of Bioengineering, University of Southern California, Los Angeles, United States.,Translational Imaging Center, University of Southern California, Los Angeles, United States
| | - David A Prober
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
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11
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Zebrafish as a model to evaluate peptide-related cancer therapies. Amino Acids 2017; 49:1907-1913. [DOI: 10.1007/s00726-017-2388-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 01/27/2017] [Indexed: 02/03/2023]
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12
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Abstract
UNLABELLED The hypothalamus plays an important role in regulating sleep, but few hypothalamic sleep-promoting signaling pathways have been identified. Here we demonstrate a role for the neuropeptide QRFP (also known as P518 and 26RFa) and its receptors in regulating sleep in zebrafish, a diurnal vertebrate. We show that QRFP is expressed in ∼10 hypothalamic neurons in zebrafish larvae, which project to the hypothalamus, hindbrain, and spinal cord, including regions that express the two zebrafish QRFP receptor paralogs. We find that the overexpression of QRFP inhibits locomotor activity during the day, whereas mutation of qrfp or its receptors results in increased locomotor activity and decreased sleep during the day. Despite the restriction of these phenotypes to the day, the circadian clock does not regulate qrfp expression, and entrained circadian rhythms are not required for QRFP-induced rest. Instead, we find that QRFP overexpression decreases locomotor activity largely in a light-specific manner. Our results suggest that QRFP signaling plays an important role in promoting sleep and may underlie some aspects of hypothalamic sleep control. SIGNIFICANCE STATEMENT The hypothalamus is thought to play a key role in regulating sleep in vertebrate animals, but few sleep-promoting signaling pathways that function in the hypothalamus have been identified. Here we use the zebrafish, a diurnal vertebrate, to functionally and anatomically characterize the neuropeptide QRFP. We show that QRFP is exclusively expressed in a small number of neurons in the larval zebrafish hypothalamus that project widely in the brain. We also show that QRFP overexpression reduces locomotor activity, whereas animals that lack QRFP signaling are more active and sleep less. These results suggest that QRFP signaling participates in the hypothalamic regulation of sleep.
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13
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Horstick EJ, Tabor KM, Jordan DC, Burgess HA. Genetic Ablation, Sensitization, and Isolation of Neurons Using Nitroreductase and Tetrodotoxin-Insensitive Channels. Methods Mol Biol 2016; 1451:355-66. [PMID: 27464821 DOI: 10.1007/978-1-4939-3771-4_25] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Advances in genetic technologies enable the highly selective expression of transgenes in targeted neuronal cell types. Transgene expression can be used to noninvasively ablate, silence or activate neurons, providing a tool to probe their contribution to the control of behavior or physiology. Here, we describe the use of the tetrodotoxin (TTX)-resistant voltage-gated sodium channel Nav1.5 for either sensitizing neurons to depolarizing input, or isolating targeted neurons from surrounding neural activity, and methods for selective neuronal ablation using the bacterial nitroreductase NfsB.
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Affiliation(s)
- Eric J Horstick
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, 20892, USA
| | - Kathryn M Tabor
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, 20892, USA
| | - Diana C Jordan
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, 20892, USA
| | - Harold A Burgess
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, 20892, USA. .,NIH, 6 Center Drive, Building 6B, Room 3B308, Bethesda, MD, 20892, USA.
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14
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Marquart GD, Tabor KM, Brown M, Strykowski JL, Varshney GK, LaFave MC, Mueller T, Burgess SM, Higashijima SI, Burgess HA. A 3D Searchable Database of Transgenic Zebrafish Gal4 and Cre Lines for Functional Neuroanatomy Studies. Front Neural Circuits 2015; 9:78. [PMID: 26635538 PMCID: PMC4656851 DOI: 10.3389/fncir.2015.00078] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 11/06/2015] [Indexed: 01/08/2023] Open
Abstract
Transgenic methods enable the selective manipulation of neurons for functional mapping of neuronal circuits. Using confocal microscopy, we have imaged the cellular-level expression of 109 transgenic lines in live 6 day post fertilization larvae, including 80 Gal4 enhancer trap lines, 9 Cre enhancer trap lines and 20 transgenic lines that express fluorescent proteins in defined gene-specific patterns. Image stacks were acquired at single micron resolution, together with a broadly expressed neural marker, which we used to align enhancer trap reporter patterns into a common 3-dimensional reference space. To facilitate use of this resource, we have written software that enables searching for transgenic lines that label cells within a selectable 3-dimensional region of interest (ROI) or neuroanatomical area. This software also enables the intersectional expression of transgenes to be predicted, a feature which we validated by detecting cells with co-expression of Cre and Gal4. Many of the imaged enhancer trap lines show intrinsic brain-specific expression. However, to increase the utility of lines that also drive expression in non-neuronal tissue we have designed a novel UAS reporter, that suppresses expression in heart, muscle, and skin through the incorporation of microRNA binding sites in a synthetic 3′ untranslated region. Finally, we mapped the site of transgene integration, thus providing molecular identification of the expression pattern for most lines. Cumulatively, this library of enhancer trap lines provides genetic access to 70% of the larval brain and is therefore a powerful and broadly accessible tool for the dissection of neural circuits in larval zebrafish.
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Affiliation(s)
- Gregory D Marquart
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health Bethesda, MD, USA ; Neuroscience and Cognitive Science Program, University of Maryland College Park, MD, USA
| | - Kathryn M Tabor
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health Bethesda, MD, USA
| | - Mary Brown
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health Bethesda, MD, USA
| | - Jennifer L Strykowski
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health Bethesda, MD, USA
| | - Gaurav K Varshney
- Translational and Functional Genomics Branch, National Human Genome Research Institute, National Institutes of Health Bethesda, MD, USA
| | - Matthew C LaFave
- Translational and Functional Genomics Branch, National Human Genome Research Institute, National Institutes of Health Bethesda, MD, USA
| | - Thomas Mueller
- Division of Biology, Kansas State University Manhattan, KS, USA
| | - Shawn M Burgess
- Translational and Functional Genomics Branch, National Human Genome Research Institute, National Institutes of Health Bethesda, MD, USA
| | - Shin-Ichi Higashijima
- National Institutes of Natural Sciences, Okazaki Institute for Integrative Bioscience, National Institute for Physiological Sciences Aichi, Japan
| | - Harold A Burgess
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health Bethesda, MD, USA ; Neuroscience and Cognitive Science Program, University of Maryland College Park, MD, USA
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15
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Das SK, Menezes ME, Bhatia S, Wang XY, Emdad L, Sarkar D, Fisher PB. Gene Therapies for Cancer: Strategies, Challenges and Successes. J Cell Physiol 2015; 230:259-71. [PMID: 25196387 DOI: 10.1002/jcp.24791] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 08/29/2014] [Indexed: 12/13/2022]
Abstract
Gene therapy, which involves replacement of a defective gene with a functional, healthy copy of that gene, is a potentially beneficial cancer treatment approach particularly over chemotherapy, which often lacks selectivity and can cause non-specific toxicity. Despite significant progress pre-clinically with respect to both enhanced targeting and expression in a tumor-selective manner several hurdles still prevent success in the clinic, including non-specific expression, low-efficiency delivery and biosafety. Various innovative genetic approaches are under development to reconstruct vectors/transgenes to make them safer and more effective. Utilizing cutting-edge delivery technologies, gene expression can now be targeted in a tissue- and organ-specific manner. With these advances, gene therapy is poised to become amenable for routine cancer therapy with potential to elevate this methodology as a first line therapy for neoplastic diseases. This review discusses recent advances in gene therapy and their impact on a pre-clinical and clinical level.
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Affiliation(s)
- Swadesh K Das
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia.,VCU Institute of Molecular Medicine, Virginia Commonwealth University, Richmond, Virginia.,VCU Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia
| | - Mitchell E Menezes
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia
| | - Shilpa Bhatia
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia
| | - Xiang-Yang Wang
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia.,VCU Institute of Molecular Medicine, Virginia Commonwealth University, Richmond, Virginia.,VCU Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia
| | - Luni Emdad
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia.,VCU Institute of Molecular Medicine, Virginia Commonwealth University, Richmond, Virginia.,VCU Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia
| | - Devanand Sarkar
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia.,VCU Institute of Molecular Medicine, Virginia Commonwealth University, Richmond, Virginia.,VCU Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia
| | - Paul B Fisher
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia.,VCU Institute of Molecular Medicine, Virginia Commonwealth University, Richmond, Virginia.,VCU Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia
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16
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The promise of zebrafish as a chemical screening tool in cancer therapy. Future Med Chem 2015; 7:1395-405. [DOI: 10.4155/fmc.15.73] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Cancer progression in zebrafish recapitulates many aspects of human cancer and as a result, zebrafish have been gaining popularity for their potential use in basic and translational cancer research. Human cancer can be modeled in zebrafish by induction using chemical mutagens, xenotransplantation or by genetic manipulation. Chemical screens based on zebrafish cancer models offer a rapid, powerful and inexpensive means of evaluating the potential of suppression or prevention on cancer. The identification of small molecules through such screens will serve as ideal entry points for novel chemical therapies for cancer treatment. This article outlines advances that have been made within the growing field of zebrafish cancer models and presents their advantages for chemical drug screening.
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17
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Wang K, Milkie D, Saxena A, Engerer P, Misgeld T, Bronner ME, Mumm J, Betzig E. Rapid adaptive optical recovery of optimal resolution over large volumes. Nat Methods 2014; 11:625-8. [PMID: 24727653 PMCID: PMC4069208 DOI: 10.1038/nmeth.2925] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 03/06/2014] [Indexed: 02/06/2023]
Abstract
Using a descanned, laser-induced guide star and direct wavefront sensing, we demonstrate adaptive correction of complex optical aberrations at high numerical aperture (NA) and a 14-ms update rate. This correction permits us to compensate for the rapid spatial variation in aberration often encountered in biological specimens and to recover diffraction-limited imaging over large volumes (>240 mm per side). We applied this to image fine neuronal processes and subcellular dynamics within the zebrafish brain.
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Affiliation(s)
- Kai Wang
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Dan Milkie
- Coleman Technologies, Inc., Newtown Square, Pennsylvania, USA
| | - Ankur Saxena
- Division of Biology, California Institute of Technology, Pasadena, California, USA
| | - Peter Engerer
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
- Munich Center for Systems Neurology, Munich, Germany
- German Center for Neurodegenerative Diseases, Munich, Germany
| | - Thomas Misgeld
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
- Munich Center for Systems Neurology, Munich, Germany
- German Center for Neurodegenerative Diseases, Munich, Germany
| | - Marianne E. Bronner
- Division of Biology, California Institute of Technology, Pasadena, California, USA
| | - Jeff Mumm
- Department of Cellular Biology and Anatomy, Georgia Regents University, Augusta, Georgia, USA
| | - Eric Betzig
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
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18
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Mathias JR, Zhang Z, Saxena MT, Mumm JS. Enhanced cell-specific ablation in zebrafish using a triple mutant of Escherichia coli nitroreductase. Zebrafish 2014; 11:85-97. [PMID: 24428354 DOI: 10.1089/zeb.2013.0937] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Transgenic expression of bacterial nitroreductase (NTR) facilitates chemically-inducible targeted cell ablation. In zebrafish, the NTR system enables studies of cell function and cellular regeneration. Metronidazole (MTZ) has become the most commonly used prodrug substrate for eliciting cell loss in NTR-expressing transgenic zebrafish due to the cell-specific nature of its cytotoxic derivatives. Unfortunately, MTZ treatments required for effective cell ablation border toxic effects, and, thus, likely incur undesirable nonspecific effects. Here, we tested whether a triple mutant variant of NTR, previously shown to display improved activity in bacterial assays, can solve this issue by promoting cell ablation in zebrafish using reduced prodrug treatment regimens. We generated several complementary transgenic zebrafish lines expressing either wild-type or mutant NTR (mutNTR) in specific neural cell types, and assayed prodrug-induced cell ablation kinetics using confocal time series imaging and plate reader-based quantification of fluorescent reporters expressed in targeted cell types. The results show that cell ablation can be achieved in mutNTR expressing transgenic lines with markedly shortened prodrug exposure times and/or at lower prodrug concentrations. The mutNTR variant characterized here can circumvent problematic nonspecific/toxic effects arising from low prodrug conversion efficiency, thus increasing the effectiveness and versatility of this selective cell ablation methodology.
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19
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Minn I, Menezes ME, Sarkar S, Yarlagadda K, Das SK, Emdad L, Sarkar D, Fisher PB, Pomper MG. Molecular-genetic imaging of cancer. Adv Cancer Res 2014; 124:131-69. [PMID: 25287688 PMCID: PMC4339000 DOI: 10.1016/b978-0-12-411638-2.00004-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Molecular-genetic imaging of cancer using nonviral delivery systems has great potential for clinical application as a safe, efficient, noninvasive tool for visualization of various cellular processes including detection of cancer, and its attendant metastases. In recent years, significant effort has been expended in overcoming technical hurdles to enable clinical adoption of molecular-genetic imaging. This chapter will provide an introduction to the components of molecular-genetic imaging and recent advances on each component leading to safe, efficient clinical applications for detecting cancer. Combination with therapy, namely, generating molecular-genetic theranostic constructs, will provide further impetus for clinical translation of this promising technology.
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Affiliation(s)
- Il Minn
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
| | | | - Siddik Sarkar
- Department of Human and Molecular Genetics, Richmond, Virginia, USA
| | - Keerthi Yarlagadda
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
| | - Swadesh K Das
- Department of Human and Molecular Genetics, Richmond, Virginia, USA; VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA
| | - Luni Emdad
- Department of Human and Molecular Genetics, Richmond, Virginia, USA; VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA; VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA
| | - Devanand Sarkar
- Department of Human and Molecular Genetics, Richmond, Virginia, USA; VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA; VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA
| | - Paul B Fisher
- Department of Human and Molecular Genetics, Richmond, Virginia, USA; VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA; VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia, USA
| | - Martin G Pomper
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, USA.
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