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Llorens-Martín M, Teixeira CM, Jurado-Arjona J, Rakwal R, Shibato J, Soya H, Ávila J. Retroviral induction of GSK-3β expression blocks the stimulatory action of physical exercise on the maturation of newborn neurons. Cell Mol Life Sci 2016; 73:3569-82. [PMID: 27010990 PMCID: PMC11108461 DOI: 10.1007/s00018-016-2181-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 10/22/2022]
Abstract
Adult hippocampal neurogenesis (AHN) is a key process for certain types of hippocampal-dependent learning. Alzheimer's disease (AD) is accompanied by memory deficits related to alterations in AHN. Given that the increased activity of GSK-3β has been related to alterations in the population of hippocampal granule neurons in AD patients, we designed a novel methodology by which to induce selective GSK-3β overexpression exclusively in newborn granule neurons. To this end, we injected an rtTA-IRES-EGFP-expressing retrovirus into the hippocampus of tTO-GSK-3β mice. Using this novel retroviral strategy, we found that GSK-3β caused a cell-autonomous impairment of the morphological and synaptic maturation of newborn neurons. In addition, we examined whether GSK-3β overexpression in newborn neurons limits the effects of physical activity. While physical exercise increased the number of dendritic spines, the percentage of mushroom spines, and the head diameter of the same in tet-OFF cells, these effects were not triggered in tet-ON cells. This observation suggests that GSK-3β blocks the stimulatory actions of exercise. Given that the activity of GSK-3β is increased in the brains of individuals with AD, these data may be relevant for non-pharmacological therapies for AD.
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Affiliation(s)
- María Llorens-Martín
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, c/Nicolás Cabrera 1, 28049, Madrid, Spain.
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII), c/Valderrebollo 5, Madrid, Spain.
| | - Catia M Teixeira
- Emotional Brain Institute, Nathan Kline Institute, New York, NY, USA
| | - Jerónimo Jurado-Arjona
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, c/Nicolás Cabrera 1, 28049, Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII), c/Valderrebollo 5, Madrid, Spain
| | - Randeep Rakwal
- Faculty of Health and Sport Sciences and Tsukuba International Academy for Sport Studies (TIAS), University of Tsukuba, Tsukuba, Ibaraki, 305-8574, Japan
- Global Research Center for Innovative Life Science, School of Pharmacy and Pharmaceutical Sciences, Hoshi University, Shinagawa, Tokyo, 142-8501, Japan
| | - Junko Shibato
- Global Research Center for Innovative Life Science, School of Pharmacy and Pharmaceutical Sciences, Hoshi University, Shinagawa, Tokyo, 142-8501, Japan
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8574, Japan
| | - Hideaki Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8574, Japan
| | - Jesús Ávila
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, c/Nicolás Cabrera 1, 28049, Madrid, Spain.
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII), c/Valderrebollo 5, Madrid, Spain.
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Tillack K, Aboutalebi H, Kramer ER. An Efficient and Versatile System for Visualization and Genetic Modification of Dopaminergic Neurons in Transgenic Mice. PLoS One 2015; 10:e0136203. [PMID: 26291828 PMCID: PMC4546329 DOI: 10.1371/journal.pone.0136203] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 07/30/2015] [Indexed: 11/18/2022] Open
Abstract
Background & Aims The brain dopaminergic (DA) system is involved in fine tuning many behaviors and several human diseases are associated with pathological alterations of the DA system such as Parkinson’s disease (PD) and drug addiction. Because of its complex network integration, detailed analyses of physiological and pathophysiological conditions are only possible in a whole organism with a sophisticated tool box for visualization and functional modification. Methods & Results Here, we have generated transgenic mice expressing the tetracycline-regulated transactivator (tTA) or the reverse tetracycline-regulated transactivator (rtTA) under control of the tyrosine hydroxylase (TH) promoter, TH-tTA (tet-OFF) and TH-rtTA (tet-ON) mice, to visualize and genetically modify DA neurons. We show their tight regulation and efficient use to overexpress proteins under the control of tet-responsive elements or to delete genes of interest with tet-responsive Cre. In combination with mice encoding tet-responsive luciferase, we visualized the DA system in living mice progressively over time. Conclusion These experiments establish TH-tTA and TH-rtTA mice as a powerful tool to generate and monitor mouse models for DA system diseases.
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Affiliation(s)
- Karsten Tillack
- Development and Maintenance of the Nervous System, Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Helia Aboutalebi
- Development and Maintenance of the Nervous System, Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Edgar R. Kramer
- Development and Maintenance of the Nervous System, Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail:
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Crotty S, Pipkin ME. In vivo RNAi screens: concepts and applications. Trends Immunol 2015; 36:315-22. [PMID: 25937561 DOI: 10.1016/j.it.2015.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 03/16/2015] [Accepted: 03/17/2015] [Indexed: 11/17/2022]
Abstract
Functional genomics approaches that leverage the RNAi pathway have been applied in vivo to examine the roles of hundreds or thousands of genes; mainly in the context of cancer. Here, we discuss principles guiding the design of RNAi screens, parameters that determine success and recent developments that have improved accuracy and expanded the applicability of these approaches to other in vivo settings, including the immune system. We review recent studies that have applied in vivo RNAi screens in T cells to examine genes that regulate T cell differentiation during viral infection, and that control their accumulation in tumors in a model of adoptive T cell therapy. In this context, we put forward an argument as to why RNAi approaches in vivo are likely to provide particularly salient insight into immunology.
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Affiliation(s)
- Shane Crotty
- Division of Vaccine Discovery, La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Matthew E Pipkin
- Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL, 33458, USA.
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Wang L, Jirka G, Rosenberg PB, Buckley AF, Gomez JA, Fields TA, Winn MP, Spurney RF. Gq signaling causes glomerular injury by activating TRPC6. J Clin Invest 2015; 125:1913-26. [PMID: 25844902 DOI: 10.1172/jci76767] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 02/27/2015] [Indexed: 01/07/2023] Open
Abstract
Familial forms of focal segmental glomerulosclerosis (FSGS) have been linked to gain-of-function mutations in the gene encoding the transient receptor potential channel C6 (TRPC6). GPCRs coupled to Gq signaling activate TRPC6, suggesting that Gq-dependent TRPC6 activation underlies glomerular diseases. Here, we developed a murine model in which a constitutively active Gq α subunit (Gq(Q209L), referred to herein as GqQ>L) is specifically expressed in podocytes and examined the effects of this mutation in response to puromycin aminonucleoside (PAN) nephrosis. We found that compared with control animals, animals expressing GqQ>L exhibited robust albuminuria, structural features of FSGS, and reduced numbers of glomerular podocytes. Gq activation stimulated calcineurin (CN) activity, resulting in CN-dependent upregulation of TRPC6 in murine kidneys. Deletion of TRPC6 in GqQ>L-expressing mice prevented FSGS development and inhibited both tubular damage and podocyte loss induced by PAN nephrosis. Similarly, administration of the CN inhibitor FK506 reduced proteinuria and tubular injury but had more modest effects on glomerular pathology and podocyte numbers in animals with constitutive Gq activation. Moreover, these Gq-dependent effects on podocyte injury were generalizable to diabetic kidney disease, as expression of GqQ>L promoted albuminuria, mesangial expansion, and increased glomerular basement membrane width in diabetic mice. Together, these results suggest that targeting Gq/TRPC6 signaling may have therapeutic benefits for the treatment of glomerular diseases.
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MESH Headings
- Albuminuria/chemically induced
- Animals
- Calcineurin/metabolism
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/genetics
- Diabetic Nephropathies/genetics
- Diabetic Nephropathies/metabolism
- Diabetic Nephropathies/pathology
- GTP-Binding Protein alpha Subunits, Gq-G11/genetics
- GTP-Binding Protein alpha Subunits, Gq-G11/physiology
- Gene Deletion
- Genes, Reporter
- Glomerulosclerosis, Focal Segmental/chemically induced
- Glomerulosclerosis, Focal Segmental/genetics
- Glomerulosclerosis, Focal Segmental/pathology
- HEK293 Cells
- Humans
- Kidney Glomerulus/pathology
- Kidney Tubules/pathology
- Mice
- Mice, Mutant Strains
- Mice, Transgenic
- NFATC Transcription Factors/metabolism
- Podocytes/metabolism
- Point Mutation
- Puromycin Aminonucleoside/toxicity
- Recombinant Fusion Proteins/metabolism
- Signal Transduction
- TRPC Cation Channels/biosynthesis
- TRPC Cation Channels/deficiency
- TRPC Cation Channels/genetics
- TRPC Cation Channels/physiology
- TRPC6 Cation Channel
- Tacrolimus/pharmacology
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5
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Hsieh YJ, Hwu L, Chen YC, Ke CC, Chen FD, Wang HE, Lin KP, Yeh HH, Chang CW, Liu RS. P21-driven multifusion gene system for evaluating the efficacy of histone deacetylase inhibitors by in vivo molecular imaging and for transcription targeting therapy of cancer mediated by histone deacetylase inhibitor. J Nucl Med 2014; 55:678-85. [PMID: 24639460 DOI: 10.2967/jnumed.113.126573] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Overexpressed histone deacetylase (HDAC) activity has been linked with tumor initiation and progression that prompt the development of histone deacetylase inhibitors (HDACIs) as anticancer agents. HDACI was reported to be able to activate p21 promoter through the SP1 binding sites in the proximal region of p21(WAF1/CIP1) promoter. In this study, we established a p21(WAF1/CIP1) promoter-driven triple-fused reporter gene system (p21-3H) to evaluate the efficacy of HDACI and the ganciclovir (GCV)-mediated anticancer effect contributed by HDACI-induced and p21-driven truncated herpes simplex virus-1 thymidine kinase sr39 mutant (ttksr39) in vitro and in vivo. METHODS The p21-3H construct was generated and stably or transiently transfected into H1299 cell lines. These cells were treated with trichostatin A or vorinostat (suberoylanilide hydroxamic acid [SAHA]) to evaluate the activation of p21 promoter-driven reporter gene expression by in vitro confocal fluorescence microscopy, luciferase assay, 2'-fluoro-2'-deoxyarabinofuranosyl-5-ethyluracil ((3)H-FEAU) cellular uptake, in vivo bioluminescence imaging, and 9-(4-(18)F-fluoro-3-hydroxymethylbutyl) guanine ((18)F-FHBG) small-animal PET imaging. The therapeutic efficacy on p21-3H-expressing tumor xenografts was assessed by daily administration with SAHA (100 mg/kg intraperitoneally) or GCV (20 mg/kg) for 9 d, followed by tumor volume measurement. RESULTS On treatment with trichostatin A or SAHA, H1299 cells carrying p21-3H showed a significant increase of luciferase activity, cellular uptake of (3)H-FEAU (Moravek), and DsRed expression. In vivo tumor xenografts carrying p21-3H also showed increased luciferase activity by luminescent imaging and enhanced accumulation of (18)F-FHBG by small-animal PET imaging. Furthermore, when cells transfected with p21-3H or p21/PstI-3H (which lacks p53-binding sites) were treated, the increase of luciferase activity was similar in both groups, indicating that HDACI-induced p21 promoter activation is independent of p53. Both in vitro and in vivo results showed improved therapeutic effect by combined treatment of GCV and HDACI. CONCLUSION We have established an HDACI-inducible, p21-driven reporter system that has the potential for evaluating the anticancer effect of HDACIs on cancer cells by multiple molecular imaging modalities. Furthermore, ttksr39 in a p21-3H reporter construct provides a potential combination with thymidine kinase-mediated gene therapy to optimize the therapeutic benefit of HDACI.
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Affiliation(s)
- Ya-Ju Hsieh
- Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan
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6
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Wang L, Tang Y, Eisner W, Sparks MA, Buckley AF, Spurney RF. Augmenting podocyte injury promotes advanced diabetic kidney disease in Akita mice. Biochem Biophys Res Commun 2014; 444:622-7. [PMID: 24491571 DOI: 10.1016/j.bbrc.2014.01.115] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 01/23/2014] [Indexed: 01/13/2023]
Abstract
To determine if augmenting podocyte injury promotes the development of advanced diabetic nephropathy (DN), we created mice that expressed the enzyme cytosine deaminase (CD) specifically in podocytes of diabetic Akita mice (Akita-CD mice). In these mice, treatment with the prodrug 5-flucytosine (5-FC) causes podocyte injury as a result of conversion to the toxic metabolite 5-fluorouracil (5-FU). We found that treatment of 4-5 week old Akita mice with 5-FC for 5 days caused robust albuminuria at 16 and 20 weeks of age compared to 5-FC treated Akita controls, which do not express CD (Akita CTLs). By 20 weeks of age, there was a significant increase in mesangial expansion in Akita-CD mice compared to Akita CTLs, which was associated with a variable increase in glomerular basement membrane (GBM) width and interstitial fibrosis. At 20 weeks of age, podocyte number was similarly reduced in both groups of Akita mice, and was inversely correlated with the albuminuria and mesangial expansion. Thus, enhancing podocyte injury early in the disease process promotes the development of prominent mesangial expansion, interstitial fibrosis, increased GBM thickness and robust albuminuria. These data suggest that podocytes play a key role in the development of advanced features of diabetic kidney disease.
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Affiliation(s)
- Liming Wang
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC 27710, United States
| | - Yuping Tang
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC 27710, United States
| | - William Eisner
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC 27710, United States
| | - Matthew A Sparks
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC 27710, United States
| | - Anne F Buckley
- Department of Pathology, Duke University Medical Center, Durham, NC 27710, United States
| | - Robert F Spurney
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC 27710, United States.
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7
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Jang J, Ahn J, Lee N, Kim ST, Kweon DH, Cho JY, Park KW, Kim S, Yoon K. Ultrasound backscatter microscopy image-guided intraventricular gene delivery at murine embryonic age 9.5 and 10.5 produces distinct transgene expression patterns at the adult stage. Mol Imaging 2014; 12. [PMID: 24447614 DOI: 10.2310/7290.2013.00067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In utero injection of a retroviral vector into the embryonic telencephalon aided by ultrasound backscatter microscopy permits introduction of a gene of interest at an early stage of development. In this study, we compared the tissue distribution of gene expression in adult mice injected with retroviral vectors at different embryonic ages in utero. Following ultrasound image-guided gene delivery (UIGD) into the embryonic telencephalon, adult mice were subjected to whole-body luciferase imaging and immunohistochemical analysis at 6 weeks and 1 year postinjection. Luciferase activity was observed in a wide range of tissues in animals injected at embryonic age 9.5 (E9.5), whereas animals injected at E10.5 showed brain-localized reporter gene expression. These results suggest that mouse embryonic brain creates a closed and impermeable structure around E10. Therefore, by injecting a transgene before or after E10, transgene expression can be manipulated to be local or systemic. Our results also provide information that widens the applicability of UIGD beyond neuroscience studies.
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8
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Wang L, Tang Y, Howell DN, Ruiz P, Spurney RF. A novel mouse model of podocyte depletion. Nephron Clin Pract 2012; 121:e10-22. [PMID: 23095233 DOI: 10.1159/000342369] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Accepted: 07/20/2012] [Indexed: 11/19/2022] Open
Abstract
AIM The goal of this study was to examine the capacity for glomerular repair after a podocyte-depleting injury. METHODS We created transgenic (TG) mice expressing the yeast enzyme cytosine deaminase specifically in glomerular podocytes. In these TG animals, the prodrug 5-flucytosine (5-FC) is converted to 5-fluorouracil and promotes cell death. RESULTS Treatment with increasing dosages of 5-FC caused graded increases in proteinuria 1-2 weeks after treatment, which returned to control levels by the 10-week time point. Light microscopic examination revealed minimal pathology at the 2-week time point, but electron microscopy revealed found foot process effacement as well as focal areas of glomerular basement membrane duplication, and immunohistochemical studies detected podocyte apoptosis and a decrease in the number of Wilms' tumor protein 1 (WT1)-positive cells. By the 10-week time point, however, the number of WT1-positive cells was similar to controls and a few mice had developed focal areas of glomerulosclerosis. Consistent with the effects of 5-FC on podocyte number, expression of the podocyte mRNAs for nephrin, podocin, synaptopodin and podocalyxin were altered in a similar temporal fashion. CONCLUSION The glomerulus has a significant capacity for repair after a podocyte-depleting injury.
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Affiliation(s)
- L Wang
- Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC 27710, USA. spurn002 @ mc.duke.edu
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9
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Abstract
Dystonia is a movement disorder characterized by involuntary muscle contractions resulting in abnormal postures. Although common in the clinic, the etiology of dystonia remains unclear. Most dystonias are idiopathic and are not associated with clear pathological brain abnormalities. Attempts to genetically model these dystonias in rodents have failed to replicate dystonic symptoms. This is at odds with the fact that rodents can exhibit dystonia. Because of this discrepancy, it is necessary to consider alternative approaches to generate phenotypically and genotypically faithful models of dystonia. Conditional knockout of dystonia-related genes is 1 technique that may prove useful for modeling genetic dystonias. Lentiviral-mediated small or short hairpin RNA (shRNA) knockdown of particular genes is another approach. Finally, in cases in which the function of a dystonia-related gene is well-known, pharmacological blockade of the protein product can be used. Such an approach was successfully implemented in the case of rapid-onset dystonia parkinsonism, DYT12. This (DYT12) is a hereditary dystonia caused by mutations in the α₃ isoform of the sodium potassium adenosine triphosphatase (ATPase) pump (sodium pump), which partially hampers its physiological function. It was found that partial selective pharmacological block of the sodium pumps in the cerebellum and basal ganglia of mice recapitulates all of the salient features of DYT12, including dystonia and parkinsonism induced by stress. This DYT12 model is unique in that it faithfully replicates human symptoms of DYT12, while targeting the genetic cause of this disorder. Acute disruption of proteins implicated in dystonia may prove a generally fruitful method to model dystonia in rodents.
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Affiliation(s)
- Rachel Fremont
- Dominic P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461 USA
| | - Kamran Khodakhah
- Dominic P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461 USA
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10
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Abstract
Podocytes are highly differentiated cells that play an important role in maintaining glomerular filtration barrier integrity; a function regulated by small GTPase proteins of the Rho family. To investigate the role of Rho A in podocyte biology, we created transgenic mice expressing doxycycline-inducible constitutively active (V14 Rho) or dominant-negative Rho A (N19 Rho) in podocytes. Specific induction of either Rho A construct in podocytes caused albuminuria and foot process effacement along with disruption of the actin cytoskeleton as evidenced by decreased expression of the actin-associated protein synaptopodin. The mechanisms of these adverse effects, however, appeared to be different. Active V14 Rho enhanced actin polymerization, caused a reduction in nephrin mRNA and protein levels, promoted podocyte apoptosis, and decreased endogenous Rho A levels. In contrast, the dominant-negative N19 Rho caused a loss of podocyte stress fibers, did not alter the expression of either nephrin or Rho A, and did not cause podocyte apoptosis. Thus, our findings suggest that Rho A plays an important role in maintaining the integrity of the glomerular filtration barrier under basal conditions, but enhancement of Rho A activity above basal levels promotes podocyte injury.
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11
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Role of dopamine receptor mechanisms in the amygdaloid modulation of fear and anxiety: Structural and functional analysis. Prog Neurobiol 2010; 90:198-216. [DOI: 10.1016/j.pneurobio.2009.10.010] [Citation(s) in RCA: 202] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 06/05/2009] [Accepted: 10/09/2009] [Indexed: 11/18/2022]
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12
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Gama Sosa MA, De Gasperi R, Elder GA. Animal transgenesis: an overview. Brain Struct Funct 2009; 214:91-109. [PMID: 19937345 DOI: 10.1007/s00429-009-0230-8] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2009] [Accepted: 11/06/2009] [Indexed: 10/20/2022]
Abstract
Transgenic animals are extensively used to study in vivo gene function as well as to model human diseases. The technology for producing transgenic animals exists for a variety of vertebrate and invertebrate species. The mouse is the most utilized organism for research in neurodegenerative diseases. The most commonly used techniques for producing transgenic mice involves either the pronuclear injection of transgenes into fertilized oocytes or embryonic stem cell-mediated gene targeting. Embryonic stem cell technology has been most often used to produce null mutants (gene knockouts) but may also be used to introduce subtle genetic modifications down to the level of making single nucleotide changes in endogenous mouse genes. Methods are also available for inducing conditional gene knockouts as well as inducible control of transgene expression. Here, we review the main strategies for introducing genetic modifications into the mouse, as well as in other vertebrate and invertebrate species. We also review a number of recent methodologies for the production of transgenic animals including retrovirus-mediated gene transfer, RNAi-mediated gene knockdown and somatic cell mutagenesis combined with nuclear transfer, methods that may be more broadly applicable to species where both pronuclear injection and ES cell technology have proven less practical.
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Affiliation(s)
- Miguel A Gama Sosa
- Department of Psychiatry, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY, 10029, USA.
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13
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Pletnikov MV. Inducible and conditional transgenic mouse models of schizophrenia. PROGRESS IN BRAIN RESEARCH 2009; 179:35-47. [PMID: 20302816 DOI: 10.1016/s0079-6123(09)17905-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Schizophrenia is a devastating disorder. Despite the advance in research techniques in the last couple of decades, the pathogenesis of the disorder still remains poorly understood. Given the lack of pathognomonic feature of the disease and difficulty to analyze molecular pathways in patients, animal models have been instrumental in advancing our understanding of the disease. Recent progress in genetics has identified candidate susceptibility genes for schizophrenia, and generation of new genetic animal models has begun to provide valuable insights into the disease development. However, the complex neurodevelopmental and heterogeneous nature of schizophrenia still poses tremendous challenges for creating credible mouse models. In this review, we will discuss how current genetic systems of temporal and conditional regulation of gene expression have shed lights on the functions of the candidate genes in mouse models of schizophrenia. We also consider the strength and weaknesses of each model. We will argue that further development of more sophisticated genetic animal models is crucial for clarifying the unknowns of schizophrenia.
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Affiliation(s)
- Mikhail V Pletnikov
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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14
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Li W, Kotoshiba S, Kaldis P. Genetic mouse models to investigate cell cycle regulation. Transgenic Res 2009; 18:491-8. [PMID: 19418238 DOI: 10.1007/s11248-009-9276-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Accepted: 04/20/2009] [Indexed: 01/21/2023]
Abstract
Early studies on cell cycle regulation were based on experiments in model systems (Yeast, Xenopus, Starfish, Drosophila) and have shaped the way we understand many events that control the cell cycle. Although these model systems are of great value, the last decade was highlighted by studies done in human cells and using in vivo mouse models. Mouse models are irreplaceable tools for understanding the genetics, development, and survival strategies of mammals. New developments in generating targeting vectors and mutant mice have improved our approaches to study cell cycle regulation and cancer. Here we summarize the most recent advances of mouse model approaches in dissecting the mechanisms of cell cycle regulation and the relevance to human disease.
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Affiliation(s)
- Weimin Li
- Department of Pharmacology, University of Wisconsin-Madison, 3725 MSC, 1300 University Avenue, Madison, WI 53706, USA
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Pérez de la Mora M, Jacobsen KX, Crespo-Ramírez M, Flores-Gracia C, Fuxe K. Wiring and volume transmission in rat amygdala. Implications for fear and anxiety. Neurochem Res 2008; 33:1618-33. [PMID: 18473172 DOI: 10.1007/s11064-008-9722-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Accepted: 04/15/2008] [Indexed: 10/22/2022]
Abstract
The amygdala plays a key role in anxiety. Information from the environment reaches the amygdaloid basolateral nucleus and after its processing is relayed to the amygdaloid central nucleus where a proper anxiogenic response is implemented. Experimental evidence indicates that in this information transfer a GABAergic interface controls the trafficking of impulses between the two nuclei. Recent work indicates that interneuronal communication can take place by classical synaptic transmission (wiring transmission) and by volume transmission in which the neurotransmitter diffuses and flows through the extracellular space from its site of release and binds to extrasynaptic receptors at various distances from the source. Based on evidence from our laboratory the concept is introduced that neurotransmitters in the amygdala can modulate anxiety involving changes in fear learning and memories by effects on receptor mosaics in the fear circuits through wiring and volume transmission modes of communication.
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Affiliation(s)
- Miguel Pérez de la Mora
- Department of Biophysics, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-253, Mexico, DF, 04510, Mexico.
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Mondragón-Rodríguez S, Basurto-Islas G, Santa-Maria I, Mena R, Binder LI, Avila J, Smith MA, Perry G, García-Sierra F. Cleavage and conformational changes of tau protein follow phosphorylation during Alzheimer's disease. Int J Exp Pathol 2008; 89:81-90. [PMID: 18336525 DOI: 10.1111/j.1365-2613.2007.00568.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Phosphorylation, cleavage and conformational changes in tau protein all play pivotal roles during Alzheimer's disease (AD). In an effort to determine the chronological sequence of these changes, in this study, using confocal microscopy, we compared phosphorylation at several sites (Ser(199/202/396/404/422)-Thr(205) and the second repeat domain), cleavage of tau (D(421)) and the canonical conformational Alz-50 epitope. While all of these posttranslational modifications are found in neurofibrillary tangles (NFTs) at all stages of the disease, we found significantly higher numbers of phospho-tau positive NFTs when compared with cleaved tau (P = 0.006 in Braak III; P = 0.002 in Braak IV; P = 0.012 in Braak V) or compared with the Alz-50 epitope (P < 0.05). Consistent with these findings, in a double transgenic mice model (Tet/GSK-3beta/VLW) overexpressing the enzyme glycogen synthase kinase-3beta (GSK-3beta) and tau with a triple FTDP-17 mutation (VLW) with AD-like neurodegeneration, phosphorylation at sites Ser(199/202)-Thr(205) was greater than truncated tau. Taken together, these data strongly support the notion that the conformational changes and truncation of tau occur after the phosphorylation of tau. We propose two probable pathways for the pathological processing of tau protein during AD, either phosphorylation and cleavage of tau followed by the Alz-50 conformational change or phosphorylation followed by the conformational change and cleavage as the last step.
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Gómez-Sintes R, Hernández F, Bortolozzi A, Artigas F, Avila J, Zaratin P, Gotteland JP, Lucas JJ. Neuronal apoptosis and reversible motor deficit in dominant-negative GSK-3 conditional transgenic mice. EMBO J 2007; 26:2743-54. [PMID: 17510631 PMCID: PMC1888681 DOI: 10.1038/sj.emboj.7601725] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Accepted: 04/24/2007] [Indexed: 12/22/2022] Open
Abstract
Increased glycogen synthase kinase-3 (GSK-3) activity is believed to contribute to the etiology of chronic disorders like Alzheimer's disease and diabetes, thus supporting therapeutic potential of GSK-3 inhibitors. However, sustained GSK-3 inhibition might induce tumorigenesis through beta-catenin-APC dysregulation. Besides, sustained in vivo inhibition by genetic means (constitutive knock-out mice) revealed unexpected embryonic lethality due to massive hepatocyte apoptosis. Here, we have generated transgenic mice with conditional (tetracycline system) expression of dominant-negative-GSK-3 as an alternative genetic approach to predict the outcome of chronic GSK-3 inhibition, either per se, or in combination with mouse models of disease. By choosing a postnatal neuron-specific promoter, here we specifically address the neurological consequences. Tet/DN-GSK-3 mice showed increased neuronal apoptosis and impaired motor coordination. Interestingly, DN-GSK-3 expression shut-down restored normal GSK-3 activity and re-established normal incidence of apoptosis and motor coordination. These results reveal the importance of intact GSK-3 activity for adult neuron viability and physiology and warn of potential neurological toxicity of GSK-3 pharmacological inhibition beyond physiological levels. Interestingly, the reversibility data also suggest that unwanted side effects are likely to revert if excessive GSK-3 inhibition is halted.
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Affiliation(s)
| | - Félix Hernández
- Centro de Biología Molecular ‘Severo Ochoa', CSIC/UAM, Madrid, Spain
| | - Analía Bortolozzi
- Departamento de Neuroquímica y Neurofarmacología, Instituto de Investigaciones Biomédicas de Barcelona (CSIC), IDIBAPS, Barcelona, Spain
| | - Francesc Artigas
- Departamento de Neuroquímica y Neurofarmacología, Instituto de Investigaciones Biomédicas de Barcelona (CSIC), IDIBAPS, Barcelona, Spain
| | - Jesús Avila
- Centro de Biología Molecular ‘Severo Ochoa', CSIC/UAM, Madrid, Spain
| | - Paola Zaratin
- Istituto di Ricerche Biomediche ‘A. Marxer', LCG-RBM/Serono Discovery, Colleretto Giacosa, Italy
| | | | - José J Lucas
- Centro de Biología Molecular ‘Severo Ochoa', CSIC/UAM, Madrid, Spain
- Centro de Biología Molecular ‘Severo Ochoa', CSIC/UAM, Campus UAM de Cantoblanco, Madrid 28049, Spain. Tel.: +34 91 497 3595/8073; Fax: +34 91 497 8087; E-mail:
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18
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van der Staay FJ. Animal models of behavioral dysfunctions: Basic concepts and classifications, and an evaluation strategy. ACTA ACUST UNITED AC 2006; 52:131-59. [PMID: 16529820 DOI: 10.1016/j.brainresrev.2006.01.006] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2005] [Revised: 01/17/2006] [Accepted: 01/17/2006] [Indexed: 12/31/2022]
Abstract
In behavioral neurosciences, such as neurobiology and biopsychology, animal models make it possible to investigate brain-behavior relations, with the aim of gaining insight into normal and abnormal human behavior and its underlying neuronal and neuroendocrinological processes. Different types of animal models of behavioral dysfunctions are reviewed in this article. In order to determine the precise criteria that an animal model should fulfill, experts from different fields must define the desired characteristics of that model at the neuropathologic and behavioral level. The list of characteristics depends on the purpose of the model. The phenotype-abnormal behavior or behavioral dysfunctions-has to be translated into testable measures in animal experiments. It is essential to standardize rearing, housing, and testing conditions, and to evaluate the reliability, validity (primarily predictive and construct validity), and biological or clinical relevance of putative animal models of human behavioral dysfunctions. This evaluation, guided by a systematic strategy, is central to the development of a model. The necessity of animal models and the responsible use of animals in research are discussed briefly.
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Affiliation(s)
- F Josef van der Staay
- Wageningen University and Research Center, Animal Sciences Group, PO Box 65, 8200 AB Lelystad, The Netherlands.
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19
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Hilton KJ, Bateson AN, King AE. A model of organotypic rat spinal slice culture and biolistic transfection to elucidate factors that drive the preprotachykinin-A promoter. ACTA ACUST UNITED AC 2004; 46:191-203. [PMID: 15464207 DOI: 10.1016/j.brainresrev.2004.07.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2004] [Indexed: 11/25/2022]
Abstract
The tachykinin substance P (SP) is a neuropeptide that is expressed in some nociceptive primary sensory afferents and in discrete populations of spinal cord neurons. Expression of spinal SP and the preprotachykinin-A (PPT-A) gene that encodes SP exhibits plasticity in response to conditions such as peripheral inflammation but the mechanisms that regulate expression are poorly understood. We have developed a spinal cord organotypic culture system that is suitable for the analysis of PPT-A gene promoter activity following biolistic transfection of recombinant DNA constructs. Spinal cord organotypic slices showed good viability over a 7-day culture period. Immunostaining for phenotypic markers such as NeuN and beta-III tubulin demonstrated preservation of neurons and their structure, although there was evidence of axotomy-induced down-regulation of NeuN in certain neuronal populations. Neurokinin-1 receptor (NK-1R) immunostaining in laminae I and III was similar to that seen in acute slices. Biolistic transfection was used to introduce DNA constructs into neurons of these organotypic cultures. Following transfection with a construct in which expression of enhanced green fluorescent protein (EGFP) is controlled by the PPT-A promoter, we showed that induction of neuronal activity by administration of a forskolin analogue/high K(+) (10 microM/10 mM) for 24 h resulted in a fourfold increase in the number of EGFP-positive cells. Similarly, a twofold increase was obtained after treatment with the NK-1R-specific agonist [Sar(9),Met (O(2))(11)]-substance P (10 microM). These data demonstrate the usefulness of this model to study physiological and pharmacological factors relevant to nociceptive processing that can modulate PPT-A promoter activity.
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Affiliation(s)
- Kathryn J Hilton
- School of Biomedical Sciences, University of Leeds, Clarendon Way, Leeds, LS2 9JT, UK
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20
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Giménez E, Lavado A, Giraldo P, Cozar P, Jeffery G, Montoliu L. A Transgenic Mouse Model with Inducible Tyrosinase Gene Expression Using the Tetracycline (Tet-on) System Allows Regulated Rescue of Abnormal Chiasmatic Projections Found in Albinism. ACTA ACUST UNITED AC 2004; 17:363-70. [PMID: 15250938 DOI: 10.1111/j.1600-0749.2004.00158.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Congenital defects in retinal pigmentation, as in oculocutaneous albinism Type I (OCA1), where tyrosinase is defective, result in visual abnormalities affecting the retina and pathways into the brain. Transgenic animals expressing a functional tyrosinase gene on an albino genetic background display a correction of all these abnormalities, implicating a functional role for tyrosinase in normal retinal development. To address the function of tyrosinase in the development of the mammalian visual system, we have generated a transgenic mouse model with inducible expression of the tyrosinase gene using the tetracycline (TET-ON) system. We have produced two types of transgenic mice: first, mice expressing the transactivator rtTA chimeric protein under the control of mouse tyrosinase promoter and its locus control region (LCR), and; second, transgenic mice expressing a mouse tyrosinase cDNA construct driven by a minimal promoter inducible by rtTA in the presence of doxycycline. Inducible experiments have been carried out with selected double transgenic mouse lines. Tyrosinase expression has been induced from early embryo development and its impact assessed with histological and biochemical methods in heterozygous and homozygous double transgenic individuals. We have found an increase of tyrosinase activity in the eyes of induced animals, compared with littermate controls. However, there was significant variability in the activation of this gene, as reported in analogous experiments. In spite of this, we could observe corrected uncrossed chiasmatic pathways, decreased in albinism, in animals induced from their first gestational week. These mice could be instrumental in revealing the role of tyrosinase in mammalian visual development.
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Affiliation(s)
- Estela Giménez
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
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21
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Kunkler PE, Kraig RP. P/Q Ca2+ channel blockade stops spreading depression and related pyramidal neuronal Ca2+ rise in hippocampal organ culture. Hippocampus 2004; 14:356-67. [PMID: 15132435 PMCID: PMC2807125 DOI: 10.1002/hipo.10181] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ca2+ channels and pyramidal cell Ca2+ are involved in hippocampal spreading depression (SD), but their roles remain elusive. Accordingly, we characterized Ca2+ changes during SD in CA3 pyramidal neurons and determined whether Ca2+ channel antagonists could prevent SD. SD was induced in hippocampal organotypic cultures (HOTCs), in which experimental conditions can be rigorously controlled. SD was triggered by transient exposure to sodium acetate (NaAc)-based Ringer's coupled to an electrical pulse in the dentate gyrus and its occurrence confirmed with interstitial DC recordings. Pyramidal cell Ca2+ was measured with fura-2 filled cells and was quantified at the soma, proximal and more distal apical dendrites. Regional Ca2+ changes began simultaneously with the triggering pulse of SD and reached three distinct peaks before returning to baseline concomitant with the interstitial DC potential of SD. The first peak occurred within 5 s of the triggering pulse, was smallest, and heralded the onset of SD. The second Ca2+ change was the greatest and reached a peak 6 s later, during the early phase of SD. The third was intermediate in size and occurred 18 s later, as SD reached its maximum interstitial DC change. SD was prevented by nonselective Ca2+ blockade (Ni2+ and Cd2+) but not by either L-Ca2+ channel (nifedipine) or N-Ca2+ channel inhibition (omega-conotoxin GVIA). Importantly, SD was blocked by P/Q Ca2+ channel antagonism (omega-agatoxin-IVA), which also prompted a significant reduction in pyramidal cell Ca2+ change and hyperexcitability. These results show that the spatiotemporal pattern of pyramidal cell Ca2+ change with SD is multiphasic; they provide further evidence that these changes begin before electrophysiologic evidence of SD. Furthermore, they show that P/Q Ca2+ channel antagonism can prevent SD in HOTCs and it appears to do so by preventing the NaAc-induced increased pyramidal cell excitability from NaAc exposure, which may involve altered GABAergic transmission.
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Affiliation(s)
- Phillip E Kunkler
- Department of Neurology, MC 2030, University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA.
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22
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Karns LR, Kisielewski A, Gulding KM, Theodorescu D. Manipulation of gene expression by an ecdysone-inducible gene switch in tumor xenografts. BMC Biotechnol 2003; 1:11. [PMID: 11782290 PMCID: PMC64497 DOI: 10.1186/1472-6750-1-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2001] [Accepted: 12/18/2001] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Rapid, robust and reversible induction of transgene expression would significantly facilitate cancer gene therapy as well as allow the in vivo functional study of newly discovered genes in tumor formation and progression. The popularity of the ecdysone inducible gene switch system has led us to investigate whether such a system can successfully regulate gene expression in a syngeneic tumor system in vivo. RESULTS MBT-2 and Panc02 carcinoma cells were transfected with components of a modification of the ecdysone switch system driving firefly luciferase (F-Luc). In vitro luciferase expression +/- ecdysone analog GS-E indicated a robust induction with minimal baseline activity and complete decay after 24 hours without drug. In vitro selection of MBT-2 transfected cell clones which had complete absence of F-Luc expression in the absence of stimulation but which expressed this gene at high levels in response to GS-E were chosen for in vivo evaluation. Tumors from engineered MBT-2 cells were grown to 5 mm in diameter prior to GS-E administration, animals euthanized and tumors removed at 6, 12 and 24 hours after GS-E administration and assayed for F-Luc activity. GS-E resulted in a maximal induction of F-Luc activity at 6 hours in tumor tissue with almost complete reversion to control levels by 12 hours. CONCLUSIONS This study is the first demonstration that robust and reversible transgene expression in tumors is feasible using the ecdysone system, allowing future rapid in vivo functional characterization of gene function or gene therapy applications.
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Affiliation(s)
- Larry R Karns
- Upstate Biotechnology Inc., Charlottesville, Virginia
| | - Anne Kisielewski
- RheoGene Inc., Charlottesville, Virginia, USA
- Present address: Upstate Biotechnology Inc., Charlottesville, Virginia, USA
| | - Kathryn M Gulding
- Department of Molecular Physiology and Biological Physics University of Virginia, Charlottesville, Virginia, USA
| | - Dan Theodorescu
- Department of Molecular Physiology and Biological Physics University of Virginia, Charlottesville, Virginia, USA
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23
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Schubert W, Yang XY, Yang TTC, Factor SM, Lisanti MP, Molkentin JD, Rincon M, Chow CW. Requirement of transcription factor NFAT in developing atrial myocardium. J Cell Biol 2003; 161:861-74. [PMID: 12796475 PMCID: PMC2172977 DOI: 10.1083/jcb.200301058] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nuclear factor of activated T cell (NFAT) is a ubiquitous regulator involved in multiple biological processes. Here, we demonstrate that NFAT is temporally required in the developing atrial myocardium between embryonic day 14 and P0 (birth). Inhibition of NFAT activity by conditional expression of dominant-negative NFAT causes thinning of the atrial myocardium. The thin myocardium exhibits severe sarcomere disorganization and reduced expression of cardiac troponin-I (cTnI) and cardiac troponin-T (cTnT). Promoter analysis indicates that NFAT binds to and regulates transcription of the cTnI and the cTnT genes. Thus, regulation of cytoskeletal protein gene expression by NFAT may be important for the structural architecture of the developing atrial myocardium.
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MESH Headings
- Active Transport, Cell Nucleus/genetics
- Animals
- Animals, Newborn
- Binding Sites/genetics
- Cell Nucleus/genetics
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Down-Regulation/genetics
- Fetus
- Gene Expression Regulation, Developmental/genetics
- Genes, Regulator/genetics
- Heart Atria/abnormalities
- Heart Atria/growth & development
- Heart Atria/metabolism
- Mice
- Mice, Transgenic
- Microscopy, Electron
- Mutation/genetics
- Myocardium/metabolism
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Myocytes, Cardiac/ultrastructure
- NFATC Transcription Factors
- Nuclear Proteins
- Promoter Regions, Genetic/genetics
- Sarcomeres/metabolism
- Sarcomeres/pathology
- Sarcomeres/ultrastructure
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Troponin I/biosynthesis
- Troponin I/genetics
- Troponin T/biosynthesis
- Troponin T/genetics
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Affiliation(s)
- William Schubert
- Dept. of Molecular Pharmacology, Albert Einstein College of Medicine, Jack and Pearl Resnick Campus, Bronx, NY 10461, USA
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24
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Modo M, Rezaie P, Heuschling P, Patel S, Male DK, Hodges H. Transplantation of neural stem cells in a rat model of stroke: assessment of short-term graft survival and acute host immunological response. Brain Res 2002; 958:70-82. [PMID: 12468031 DOI: 10.1016/s0006-8993(02)03463-7] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The use of progenitors and stem cells for neural grafting is promising, as these not only have the potential to be maintained in vitro until use, but may also prove less likely to evoke an immunogenic response in the host, when compared to primary (fetal) grafts. We investigated whether the short-term survival of a grafted conditionally immortalised murine neuroepithelial stem cell line (MHP36) (2 weeks post-implantation, 4 weeks post-ischaemia) is influenced by: (i) immunosuppression (cyclosporin A (CSA) vs. no CSA), (ii) the local (intact vs. lesioned hemisphere), or (iii) global (lesioned vs. sham) brain environment. MHP36 cells were transplanted ipsi- and contralateral to the lesion in rats with middle cerebral artery occlusion (MCAo) or sham controls. Animals were either administered CSA or received no immunosuppressive treatment. A proliferation assay of lymphocytes dissociated from cervical lymph nodes, grading of the survival of the grafted cells, and histological evaluation of the immune response revealed no significant difference between animals treated with or without CSA. There was no difference in survival or immunological response to cells grafted ipsi- or contralateral to the lesion. Although a local upregulation of immunological markers (MHC class I, MHC class II, CD45, CD11b) was detected around the injection site and the ischaemic lesion, these were not specifically upregulated in response to transplanted cells. These results provide evidence for the low immunogenic properties of MHP36 cells during the initial period following implantation, known to be associated with an acute host immune response and ensuing graft rejection.
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Affiliation(s)
- Michel Modo
- Neuroimaging Research Group-Neurology P042, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK.
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25
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Schmeisser F, Donohue M, Weir JP. Tetracycline-regulated gene expression in replication-incompetent herpes simplex virus vectors. Hum Gene Ther 2002; 13:2113-24. [PMID: 12542843 DOI: 10.1089/104303402320987815] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Although herpes simplex virus (HSV) vectors appear to have great potential as gene delivery vectors both in vitro and in vivo, the expression of foreign genes in such vectors cannot be easily regulated. Of the known eukaryotic regulatory systems, the tetracycline-inducible gene expression system is perhaps the most widely used because of its induction characteristics and because of the well-known pharmacological properties of tetracycline (Tet) and analogs such as doxycycline. Here, we describe the adaptation of the Tet-inducible system for use in replication-incompetent HSV vectors. HSV vectors were constructed that contained several types of Tet-inducible promoters for foreign gene expression. These promoters contained a tetracycline response element (TRE) linked to either a minimal cytomegalovirus (CMV) immediate-early promoter, a minimal HSV ICP0 promoter, or a truncated HSV ICP0 promoter containing one copy of the HSV TAATGARAT cis-acting immediate-early regulatory element (where R represents a prime base). All three promoter constructs were regulated appropriately by doxycycline, as shown by the expression of the marker gene lacZ in cell lines engineered to express Tet transactivators. The ICP0 promoter constructs expressed the highest and most sustained levels of lacZ, but the CMV promoter construct had the highest relative level of induction, suggesting their use in different applications. To extend the utility of Tet-regulated HSV vectors, vectors were constructed that coexpressed an inducible Tet transactivator in addition to the inducible lacZ marker gene. This modification resulted in tetracycline-inducible gene expression that was not restricted to specific cell lines, and this vector was capable of inducible expression in irreversibly differentiated NT2 cells (NT-neurons) for several days. Finally, HSV vectors were constructed that expressed modified Tet transactivators, resulting in improved induction properties and indicating the flexibility of the Tet-regulated system for regulation of foreign gene expression in HSV vector-infected cells.
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Affiliation(s)
- Falko Schmeisser
- Laboratory of DNA Viruses, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA
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26
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Lin W, Albanese C, Pestell RG, Lawrence DS. Spatially discrete, light-driven protein expression. CHEMISTRY & BIOLOGY 2002; 9:1347-53. [PMID: 12498888 DOI: 10.1016/s1074-5521(02)00288-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Transgene-based inducible expression systems offer the potential to study the influence of any gene at any point during an organism's lifetime. However, the expression of individual genes is both temporally and spatially (i.e., cell/tissue)-regulated. The inducible gene expression systems devised to date do not offer fine spatial control over gene expression. We describe herein the creation and study of a light-activatable, ecdysone-inducible gene expression system. We have constructed the first example of a caged ecdysteroid, which is virtually inactive as an inducing agent in a luciferase-based gene expression system. However, upon exposure to brief illumination, the caged ecdysteroid is rapidly converted into active beta-ecdysone. Caged beta-ecdysone is cell permeable, can be intracellularly photouncaged, and, in combination with spot illumination, can be used to drive spatially discrete protein expression in a multicellular setting.
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Affiliation(s)
- Weiying Lin
- Department of Biochemistry, The Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461, USA
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27
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Albanese C, Hulit J, Sakamaki T, Pestell RG. Recent advances in inducible expression in transgenic mice. Semin Cell Dev Biol 2002; 13:129-41. [PMID: 12240598 DOI: 10.1016/s1084-9521(02)00021-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In order to accurately analyze gene function in transgenic mice, as well as to generate credible murine models of human diseases, the ability to regulate temporal- and spatial-specific expression of target genes is absolutely critical. Pioneering work in inducible transgenics, begun in the 1980s and continuing to the present, has led to the development of a variety of different inducible systems dedicated to this goal, the shared basis of which is the accurate conditional expression of a given transgene. Recent advances in inducible transgene expression in mice are discussed.
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Affiliation(s)
- Chris Albanese
- Department of Developmental and Molecular Biology, The Albert Einstein Cancer Center, Division of Hormone-Dependent Tumor Biology, Albert Einstein College of Medicine, Bronkx, NY 10461, USA.
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28
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Yamamoto A, Hen R, Dauer WT. The ons and offs of inducible transgenic technology: a review. Neurobiol Dis 2001; 8:923-32. [PMID: 11741388 DOI: 10.1006/nbdi.2001.0452] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Classical transgenic and gene-targeted mouse mutants are powerful model systems in which to study the pathogenesis of neurodegenerative diseases. However, a number of issues of fundamental importance to neurodegenerative research cannot be addressed using classical techniques. These include identification of the earliest events in disease pathogenesis and a determination of whether a particular pathogenic protein produces a inexorable or a reversible disease process. Both of these issues have profound implications for the rational development of new therapies. To address these questions, genetic techniques that allow pathogenic proteins to be expressed or knocked out with temporal and regional specificity have been developed. We have reviewed these systems, highlighting the tetracycline-regulated system because of its demonstrated utility in mice and its reversibility. These regulatable systems are a new and powerful tool for the neurobiologist and allow one to address a new set of important questions in an in vivo setting.
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Affiliation(s)
- A Yamamoto
- Department of Pharmacology, Columbia University, New York, New York 10032, USA.
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29
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30
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Ravi M, Hopfinger AJ, Hormann RE, Dinan L. 4D-QSAR analysis of a set of ecdysteroids and a comparison to CoMFA modeling. JOURNAL OF CHEMICAL INFORMATION AND COMPUTER SCIENCES 2001; 41:1587-604. [PMID: 11749586 DOI: 10.1021/ci010076u] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ecdysteroid-responsive Drosophila melanogaster B(II) cell line is a prototypical homologous inducible gene expression system. A training set of 71 ecdysteroids, for which the -log(EC(50)) potencies in the ecdysteroid-responsive B(II) cell line were measured, was used to construct 4D-QSAR models. Four nearly equivalent optimum 4D-QSAR models, for two modestly different alignments, were identified (Q(2) = 0.76-0.80). These four models, together with two CoMFA models, were used in consensus modeling to arrive at a three-dimensional pharmacophore. The C-2 and C-22 hydroxyls are identified as hydrogen-bond acceptor sites which enhance activity. A hydrophobic site near C-12 is consistent with increasing activity. The side-chain substituents at C-17 are predicted to adopt semiextended "active" conformations which could fit into a cylinder-shaped binding pocket lined largely with nonpolar residues for enhanced activity. A test set of 20 ecdysteroids was used to evaluate the QSAR models. Two 4D-QSAR models for one alignment were identified to be superior to the others based on having the smallest average residuals of prediction for the prediction set (0.69 and 1.13 -log[EC(50)] units). The correlation coefficients of the optimum 4D-QSAR models (R(2) = 0.87 and 0.88) are nearly the same as those of the best CoMFA model (R(2) = 0.92) determined for the same training set. However, the cross-validation correlation coefficient of the CoMFA model is less significant (Q(2) = 0.59) than those of the 4D-QSAR models (Q(2) = 0.80 and 0.80).
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Affiliation(s)
- M Ravi
- Laboratory of Molecular Modeling and Design (M/C-781), College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, IL 60612-7231, USA
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31
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Abstract
Behavioural phenotyping of mouse mutants is not a goal in itself but serves to characterise the behavioural effects of naturally occurring or experimentally induced mutations. Genetically engineered mouse mutants are valuable tools to elucidate the genetic control of behaviour and the interaction between genetic and environmental factors. However, a prerequisite for their use is the ability to assess different elements of behaviour. To this end, a battery of tests, which should be flexible enough to meet the needs of a particular study, should be used to characterise the behavioural phenotype. Detailed and extensive information about the effects of gene mutations is crucial for model building and model evaluation. Model building is an iterative process, switching between experimental data and theory formation. In order to facilitate this process and to allow comparison of results within and between laboratories, the standardisation of breeding, housing, and testing conditions is essential. The development and standardisation of sensitive, valid behavioural tests which are suited to phenotype mouse mutants is both a responsibility and a challenge to investigators of mouse behaviour.
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Affiliation(s)
- F J van der Staay
- Cognitive Neurobiology, Institute for Anatomy II, University of Köln, Joseph Stelzmann Str. 9, 50931 Cologne, Germany
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32
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Abstract
Genetically engineered animal models have been and will continue to be invaluable for exploring the basic mechanisms involved in the aging process as well as in extending our understanding of diseases found to be more prevalent in the older human population. Continued development of such in vivo systems will allow scientists to further dissect the role genetic and environmental factors play in aging and in age-related disease states and to enhance our understanding of these processes. In this article we discuss techniques involved in the development of such models and review some examples of laboratory mouse strains that have been used to study either normal aging or select diseases associated with aging.
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Affiliation(s)
- J K Andersen
- Buck Institute for Age Research, 8001 Redwood Boulevard, Novato, CA 94945, USA.
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33
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Jia Z, Lu YM, Agopyan N, Roder J. Gene targeting reveals a role for the glutamate receptors mGluR5 and GluR2 in learning and memory. Physiol Behav 2001; 73:793-802. [PMID: 11566212 DOI: 10.1016/s0031-9384(01)00516-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
This work suggests that class I mGluRs are involved in long-term potentiation (LTP) at CA1 synapses within the hippocampus. Our data support a pathway linking class I-mGluRs with PKC and src to enhance the open probability of the NMDAR channel. This leads to LTP of the NMDAR, but not the AMPAR. We are currently analyzing double mGluR1 X mGluR5 knockouts with Collingridge for a loss of the LTP induction switch [Nature 368 (1994) 740.]. This induction of LTP of the NMDAR is necessary for "spatial" learning and memory to occur, since mice lacking the mGluR5 are deficient in the Morris water maze and context-dependent fear conditioning. We postulate that AMPARs may provide negative feedback inhibition to the NMDAR. Hence, in null mutants lacking the AMPAR subtype, GluR2, LTP in the CA1 region of hippocampal slices was markedly enhanced (twofold) and non-saturating, whereas neuronal excitability and paired-pulse facilitation were normal. The ninefold increase in Ca(2+) permeability, in response to kainate application, suggests one possible mechanism for enhanced LTP. Enhanced LTP could result from enhanced AMPAR channel conductance or increased recruiting of previously silent synapses. Since the GluR2 null mutants showed reduced exploration and impaired motor coordination, we could make no conclusion about its role in learning and memory. Future work will be directed to inducible deletion of GluR2 only in CA1 after development is complete. These results support the correlation between LTP and learning and memory.
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Affiliation(s)
- Z Jia
- Division of Neuroscience, Hospital for Sick Children, Room 6028, McMaster Building, 555 University Avenue, Toronto, Ontario, M5G 1X5 Canada.
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34
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Wells T, Carter DA. Genetic engineering of neural function in transgenic rodents: towards a comprehensive strategy? J Neurosci Methods 2001; 108:111-30. [PMID: 11478971 DOI: 10.1016/s0165-0270(01)00391-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
As mammalian genome projects move towards completion, the attention of molecular neuroscientists is currently moving away from gene identification towards both cell-specific gene expression patterns (neuronal transcriptions) and protein expression/interactions (neuronal proteomics). In the long term, attention will increasingly be directed towards experimental interventions which are able to question neuronal function in a sophisticated manner that is cognisant of both transcriptomic and proteomic organization. Central to this effort will be the application of a new generation of transgenic approaches which are now evolving towards an appropriate level of molecular, temporal and spatial resolution. In this review, we summarize recent developments in transgenesis, and show how they have been applied in the principal model species for neuroscience, namely rats and mice. Current concepts of transgene design are also considered together with an overview of new genetically-encoded tools including both cellular indicators such as fluorescent activity reporters, and cellular regulators such as dominant negative signalling factors. Application of these tools in a whole animal context can be used to question both basic concepts of brain function, and also current concepts of underlying dysfuction in neurological diseases.
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Affiliation(s)
- T Wells
- School of Biosciences, Cardiff University, PO Box 911, Museum Avenue, Cardiff CF10 3US, UK
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35
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de Almeida LP, Zala D, Aebischer P, Déglon N. Neuroprotective effect of a CNTF-expressing lentiviral vector in the quinolinic acid rat model of Huntington's disease. Neurobiol Dis 2001; 8:433-46. [PMID: 11442352 DOI: 10.1006/nbdi.2001.0388] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurodegenerative diseases represent promising targets for gene therapy approaches provided effective transfer vectors. In the present study, we evaluated the effectiveness of LacZ-expressing lentiviral vectors with two different internal promoters, the mouse phosphoglycerate kinase 1 (PGK) and cytomegalovirus (CMV), to infect striatal cells. The intrastriatal injection of lenti-beta-Gal vectors lead to 207, 400 +/- 11,500 and 303,100 +/- 4,300 infected cells in adult rats, respectively. Importantly, the beta-galactosidase activity was higher in striatal extracts from PGK-LacZ-injected animals as compared to CMV-LacZ animals. The efficacy of the system was further examined with a potential therapeutic gene for the treatment of Huntington's disease, the human ciliary neurotrophic factor (CNTF). PGK-LacZ- or PGK-CNTF-expressing viruses were stereotaxically injected into the striatum of rats, 3 weeks later the animals were unilaterally lesioned with 180 nmol of quinolinic acid (QA). Control animals displayed 148 +/- 43 apomorphine-induced rotations ipsilateral to the lesion 5 days postlesion as compared to 26 +/- 22 turns/45 min in the CNTF-treated group. The extent of the striatal damage was significantly diminished in the CNTF-treated rats as indicated by the 52 +/- 9.7% decrease of the lesion volume and the sparing of DARPP-32, ChAT and NADPH-d neuronal populations. These results further establish that lentiviruses may represent an efficient gene delivery system for the screening of therapeutic molecules in Huntington's disease.
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Affiliation(s)
- L P de Almeida
- Division of Surgical Research and Gene Therapy Center, Lausanne Medical School, Switzerland
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36
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Price DL, Wong PC, Markowska AL, Lee MK, Thinakaren G, Cleveland DW, Sisodia SS, Borchelt DR. The value of transgenic models for the study of neurodegenerative diseases. Ann N Y Acad Sci 2001; 920:179-91. [PMID: 11193148 DOI: 10.1111/j.1749-6632.2000.tb06920.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Transgenic animal models are useful in studying the features of APP- and PS1-linked FAD and SOD1-linked FALS. These models help to investigate the nature of the cellular/biochemical/molecular alterations in neural tissue; the character and evolution of neuronal and/or glial abnormalities; the ways mutant proteins cause damage to neurons; and the biochemical pathways associated with cell death. New technologies will help to define changes in a variety of genes/gene products and the events and conformational changes in mutant proteins that are implicated in pathogenic cascades. It is hoped such study will result in novel treatments for testing in transgenic models that can then be translated into new treatments for human neurodegenerative diseases.
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Affiliation(s)
- D L Price
- Division of Neuropathology, Johns Hopkins University School of Medicine, 558 Ross Research Building, 720 Rutland Avenue, Baltimore, Maryland 21205-2196, USA.
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37
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Yen L, Gonzalez-Zulueta M, Feldman A, Yuan Y, Fryer H, Dawson T, Dawson V, Kalb RG. Reduction of functional N-methyl-D-aspartate receptors in neurons by RNase P-mediated cleavage of the NR1 mRNA. J Neurochem 2001; 76:1386-94. [PMID: 11238723 DOI: 10.1046/j.1471-4159.2001.00153.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
One approach to studying the functional role of individual NMDA receptor subunits involves the reduction in the abundance of the protein subunit in neurons. We have pursued a strategy to achieve this goal that involves the use of a small guide RNA which can lead to the destruction of the mRNA for a specific receptor subunit. We designed a small RNA molecule, termed 'external guide sequence' (EGS), which binds to the NR1 mRNA and directs the endonuclease RNase P to cleave the target message. This EGS has exquisite specificity and directed the RNase P-dependent cleavage at the targeted location within the NR1 mRNA. To improve the efficiency of this EGS, an in vitro evolution strategy was employed which led to a second generation EGS that was 10 times more potent than the parent molecule. We constructed an expression cassette by flanking the EGS with self-cleaving ribozymes and this permitted generation of the specified EGS RNA sequence from any promoter. Using a recombinant Herpes simplex virus (HSV), we expressed the EGS in neurons and showed the potency of the EGS to reduce NR1 protein within neurons. In an excitotoxicity assay, we showed that expression of the EGS in cortical neurons is neuroprotective. Our results demonstrate the utility of EGSs to reduce the expression of any gene (and potentially any splice variant) in neurons.
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MESH Headings
- Animals
- Base Sequence
- Cells, Cultured
- Cerebral Cortex/cytology
- Cerebral Cortex/physiology
- Embryo, Mammalian
- Endoribonucleases/metabolism
- Genetic Vectors
- Molecular Sequence Data
- N-Methylaspartate/toxicity
- Neurons/cytology
- Neurons/drug effects
- Neurons/physiology
- Oligodeoxyribonucleotides/chemistry
- Promoter Regions, Genetic
- RNA Editing
- RNA, Catalytic/chemistry
- RNA, Catalytic/metabolism
- RNA, Messenger/chemistry
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Receptors, N-Methyl-D-Aspartate/genetics
- Ribonuclease P
- Ribonuclease T1/metabolism
- Simplexvirus/genetics
- RNA, Small Untranslated
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Affiliation(s)
- L Yen
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA
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38
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Copin JC, Gasche Y, Li Y, Chan PH. Prolonged hypoxia during cell development protects mature manganese superoxide dismutase-deficient astrocytes from damage by oxidative stress. FASEB J 2001; 15:525-34. [PMID: 11156968 DOI: 10.1096/fj.00-0330com] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mouse astrocytes deficient in the mitochondrial form of superoxide dismutase do not grow in culture under 20% atmospheric O2 levels. By flow cytometry, immunocytochemistry, and enzymatic analysis we have shown that the oxygen block of cell division is due to a decrease in the number of cells entering the S phase of the cell cycle and is concomitant with higher DNA oxidation and impairment of mitochondrial functions. Seeding the cells under 5% O2 until the cultures become confluent can circumvent this problem. An initial hypoxic environment increases the resistance of manganese superoxide dismutase-deficient astrocytes to superoxide radicals artificially produced by paraquat treatment, preserves respiratory activity, and allows normoxic division during a subsequent passage. DNA oxidation is then not higher than in wild-type control cells. However, the adaptation of the cells is not due to compensation by other enzymes of the antioxidant defense system and is specific to cells totally lacking manganese superoxide dismutase. Alteration of the phenotype by prior hypoxia exposure in the SOD2-deficient mutant provide a unique model to study adaptative mechanisms of cellular resistance to oxygen toxicity.
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Affiliation(s)
- J C Copin
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California 94305-5487 USA
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39
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Lucas JJ, Hernández F, Gómez-Ramos P, Morán MA, Hen R, Avila J. Decreased nuclear beta-catenin, tau hyperphosphorylation and neurodegeneration in GSK-3beta conditional transgenic mice. EMBO J 2001; 20:27-39. [PMID: 11226152 PMCID: PMC140191 DOI: 10.1093/emboj/20.1.27] [Citation(s) in RCA: 691] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Glycogen synthase kinase-3beta (GSK-3beta) has been postulated to mediate Alzheimer's disease tau hyperphosphorylation, beta-amyloid-induced neurotoxicity and presenilin-1 mutation pathogenic effects. By using the tet-regulated system we have produced conditional transgenic mice overexpressing GSK-3beta in the brain during adulthood while avoiding perinatal lethality due to embryonic transgene expression. These mice show decreased levels of nuclear beta-catenin and hyperphosphorylation of tau in hippocampal neurons, the latter resulting in pretangle-like somatodendritic localization of tau. Neurons displaying somatodendritic localization of tau often show abnormal morphologies and detachment from the surrounding neuropil. Reactive astrocytosis and microgliosis were also indicative of neuronal stress and death. This was further confirmed by TUNEL and cleaved caspase-3 immunostaining of dentate gyrus granule cells. Our results demonstrate that in vivo overexpression of GSK-3beta results in neurodegeneration and suggest that these mice can be used as an animal model to study the relevance of GSK-3beta deregulation to the pathogenesis of Alzheimer's disease.
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Affiliation(s)
| | | | - Pilar Gómez-Ramos
- Centro de Biología Molecular ‘Severo Ochoa’, CSIC/Universidad Autónoma de Madrid,
Departamento de Morfología, Facultad de Medicina, Universidad Autónoma de Madrid, 28049 Madrid, Spain and Center for Neurobiology and Behavior, Columbia University, New York, NY, USA Corresponding author e-mail: J.J.Lucas and F.Hernández contributed equally to this work
| | - María A. Morán
- Centro de Biología Molecular ‘Severo Ochoa’, CSIC/Universidad Autónoma de Madrid,
Departamento de Morfología, Facultad de Medicina, Universidad Autónoma de Madrid, 28049 Madrid, Spain and Center for Neurobiology and Behavior, Columbia University, New York, NY, USA Corresponding author e-mail: J.J.Lucas and F.Hernández contributed equally to this work
| | - René Hen
- Centro de Biología Molecular ‘Severo Ochoa’, CSIC/Universidad Autónoma de Madrid,
Departamento de Morfología, Facultad de Medicina, Universidad Autónoma de Madrid, 28049 Madrid, Spain and Center for Neurobiology and Behavior, Columbia University, New York, NY, USA Corresponding author e-mail: J.J.Lucas and F.Hernández contributed equally to this work
| | - Jesús Avila
- Centro de Biología Molecular ‘Severo Ochoa’, CSIC/Universidad Autónoma de Madrid,
Departamento de Morfología, Facultad de Medicina, Universidad Autónoma de Madrid, 28049 Madrid, Spain and Center for Neurobiology and Behavior, Columbia University, New York, NY, USA Corresponding author e-mail: J.J.Lucas and F.Hernández contributed equally to this work
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40
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Saez E, Nelson MC, Eshelman B, Banayo E, Koder A, Cho GJ, Evans RM. Identification of ligands and coligands for the ecdysone-regulated gene switch. Proc Natl Acad Sci U S A 2000; 97:14512-7. [PMID: 11114195 PMCID: PMC18950 DOI: 10.1073/pnas.260499497] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ecdysone-inducible gene switch is a useful tool for modulating gene expression in mammalian cells and transgenic animals. We have identified inducers derived from plants as well as certain classes of insecticides that increase the versatility of this gene regulation system. Phytoecdysteroids share the favorable kinetics of steroids, but are inert in mammals. The gene regulation properties of one of these ecdysteroids have been examined in cell culture and in newly developed strains of ecdysone-system transgenic mice. Ponasterone A is a potent regulator of gene expression in cells and transgenic animals, enabling reporter genes to be turned on and off rapidly. A number of nonsteroidal insecticides have been identified that also activate the ecdysone system. Because the gene-controlling properties of the ecdysone switch are based on a heterodimer composed of a modified ecdysone receptor (VgEcR) and the retinoid X receptor (RXR), we have tested the effect of RXR ligands on the VgEcR/RXR complex. Used alone, RXR ligands display no activity on the ecdysone switch. However, when used in combination with a VgEcR ligand, RXR ligands dramatically enhance the absolute levels of induction. This property of the heterodimer has allowed the development of superinducer combinations that increase the dynamic range of the system.
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Affiliation(s)
- E Saez
- The Salk Institute for Biological Studies, Howard Hughes Medical Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
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41
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Abstract
We have developed a simple computer-based discrimination task that enables the quick determination of visual acuities in rodents. A grating is displayed randomly on one of two monitors at the wide end of a trapezoidal-shaped tank containing shallow water. Animals are trained to swim toward the screens, and at a fixed distance, choose the screen displaying the grating and escape to a submerged platform hidden below it. Both mice and rats learn the task quickly. Performance falls below 70% when the spatial frequency is increased beyond 0.5 cycles in most C57BU6 mice, and around 1.0 cycles per degree (cpd) in Long-Evans rats.
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Affiliation(s)
- G T Prusky
- Department of Psychology and Neuroscience, The University of Lethbridge, 4401 University Drive, AB, TIK 3M4, Lethbridge, Canada.
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42
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Lüers GH, Jess N, Franz T. Reporter-linked monitoring of transgene expression in living cells using the ecdysone-inducible promoter system. Eur J Cell Biol 2000; 79:653-7. [PMID: 11043406 DOI: 10.1078/0171-9335-00086] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Inducible promoter systems such as the ecdysone-inducible system or the tetracycline-regulated expression systems have proven to be powerful tools in studying gene function. In practice, such systems have met with the difficulty that either the vector expressing the transactivator gene or the vector carrying the response element are frequently silenced by flanking genomic sequences after stable integration. In order to identify those cells in a heterogeneous population in which a transgene is expressed from an ecdysone-inducible promoter, we have created the vector p2ER-EGFP/mcs that contains two ecdysone-inducible expression cassettes in tandem. Using two reporter genes, lacZ and green fluorescent protein (EGFP), we demonstrate that the expression of both genes can be co-induced from a very low baseline in CHO cells expressing the modified ecdysone receptor and the retinoid X receptor. The expression of EGFP and lacZ from vector p2ER-EGFP/lacZ follows the same Muristerone A concentration-dependence as that of EGFP from vector pER-EGFP, indicating that the juxtaposition of the two inducible promoters in vector p2ER-EGFP/mcs does not cause cross interference between them. We suggest that this modification of the ecdysone-inducible promoter system will allow for the visual control of the induced expression of other genes by Muristerone A.
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Affiliation(s)
- G H Lüers
- University of Bonn, Institute for Anatomy, Germany
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43
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Haas SJ, Bauer P, Rolfs A, Wree A. Immunocytochemical characterization of in vitro PKH26-labelled and intracerebrally transplanted neonatal cells. Acta Histochem 2000; 102:273-80. [PMID: 10990065 DOI: 10.1078/s0065-1281(04)70035-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The lipophilic dye PKH26 that binds irreversibly to cell membranes has been used to label various cell types in vitro prior to transplantation in order to recognize grafted cells posttransplantationally in the host tissue by fluorescence microscopy. The purpose of the present study was to optimize immunocytochemical staining procedures for PKH26-containing specimens in cell culture and after transplantation into rat brain. We demonstrated that freeze-thawing allowed for proper immunostaining of intracellular epitopes whereas PKH26-labelling was preserved. PKH26-labelled donor cells were detectable at least up to 4 months after transplantation in the host brain.
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Affiliation(s)
- S J Haas
- Institute of Anatomy, University of Rostock, Germany
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44
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Chen JF, Beilstein M, Xu YH, Turner TJ, Moratalla R, Standaert DG, Aloyo VJ, Fink JS, Schwarzschild MA. Selective attenuation of psychostimulant-induced behavioral responses in mice lacking A(2A) adenosine receptors. Neuroscience 2000; 97:195-204. [PMID: 10771351 DOI: 10.1016/s0306-4522(99)00604-1] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A(2A) adenosine receptors are highly expressed in the striatum where they modulate dopaminergic activity. The role of A(2A) receptors in psychostimulant action is less well understood because of the lack of A(2A)-selective compounds with access to the central nervous system. To investigate the A(2A) adenosinergic regulation of psychostimulant responses, we examined the consequences of genetic deletion of A(2A) receptors on psychostimulant-induced behavioral responses. The extent of dopaminergic innervation and expression of dopamine receptors in the striatum were indistinguishable between A(2A) receptor knockout and wild-type mice. However, locomotor responses to amphetamine and cocaine were attenuated in A(2A) knockout mice. In contrast, D(1)-like receptor agonists SKF81297 and SKF38393 produced identical locomotor stimulation and grooming, respectively, in wild-type and A(2A) knockout mice. Similarly, the D(2)-like agonist quinpirole produced motor-depression and stereotypy that were indistinguishable between A(2A) knockout and wild-type mice. Furthermore, attenuated amphetamine- (but not SKF81297-) induced locomotion was observed in pure 129-Steel as well as hybrid 129-SteelxC57BL/6 mice, confirming A(2A) receptor deficiency (and not genetic background) as the cause of the blunted psychostimulant responses in A(2A) knockout mice. These results demonstrate that A(2A) receptor deficiency selectively attenuates psychostimulant-induced behavioral responses and support an important role for the A(2A) receptor in modulating psychostimulant effects.
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MESH Headings
- Animals
- Behavior, Animal/drug effects
- Behavior, Animal/physiology
- Brain/cytology
- Brain/drug effects
- Brain/metabolism
- Central Nervous System Stimulants/pharmacology
- Cocaine/pharmacology
- Dopamine/metabolism
- Dopamine Agonists/pharmacology
- Dopamine Uptake Inhibitors/pharmacology
- Genotype
- Locomotion/drug effects
- Locomotion/physiology
- Mice
- Mice, Knockout
- Neostriatum/cytology
- Neostriatum/drug effects
- Neostriatum/metabolism
- Phenotype
- Receptor, Adenosine A2A
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D1/analysis
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D2/agonists
- Receptors, Dopamine D2/analysis
- Receptors, Dopamine D2/metabolism
- Receptors, Purinergic P1/deficiency
- Receptors, Purinergic P1/drug effects
- Receptors, Purinergic P1/genetics
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Affiliation(s)
- J F Chen
- Molecular Neurobiology Laboratory and Neurology Research Laboratory, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02129, USA
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45
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DePrato Primeaux S, Holmes PV, Martin RJ, Dean RG, Edwards GL. Experimentally induced attenuation of neuropeptide-Y gene expression in transgenic mice increases mortality rate following seizures. Neurosci Lett 2000; 287:61-4. [PMID: 10841991 DOI: 10.1016/s0304-3940(00)01137-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Previous experiments have reported increased seizure susceptibility in transgenic mice lacking normal neuropeptide-Y (NPY) gene expression (i.e. NPY 'knock-out' mice). A critical issue inherent in such experiments concerns the confounding of developmental influences of NPY and its neurotransmitter functions in the mature organism. The present experiments directly addressed this issue by studying seizure susceptibility in transgenic mice possessing an inducible antisense transcript that can be experimentally manipulated to attenuate NPY synthesis. NPY-deficient and control mice were injected with kainic acid (40 mg/kg, i.p.) and several seizure-related behaviors were measured. Consistent with previously reported effects in NPY knock-out mice, significantly more NPY-deficient mice died within 24 h than control mice. In situ hybridization analyses confirmed a decrease in prepro-NPY gene expression in transgenic mice. The experiments support the hypothesis that the control of neural excitability is a prominent function of NPY.
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Affiliation(s)
- S DePrato Primeaux
- Department of Psychology, The University of Georgia, Athens, GA 30602, USA
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46
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Abstract
The establishment of novel animal models using gene targeting and transgenic technology has opened a new area of neuropharmacological research. For the first time, it became possible to alter the expression of a gene in a specific cell type of an intact animal by either overexpression, inhibition or ablation. This review describes the technology and lists the relevant tools, such as reporter genes, suicide genes, immortalizing genes, and promoters, necessary for the targeted expression of these and other genes in specific cells of the central nervous system. In addition, the problem is discussed that the mouse is the species in which this technology is by far the most developed, while the rat has been used as the model species for neuropharmacology during the last century.
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Affiliation(s)
- M Bader
- Max-Delbrück-Center for Molecular Medicine, Transgenics in Berlin-Buch GmbH, Berlin, Germany
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47
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Hoppe UC, Marbán E, Johns DC. Adenovirus-mediated inducible gene expression in vivo by a hybrid ecdysone receptor. Mol Ther 2000; 1:159-64. [PMID: 10933926 DOI: 10.1006/mthe.1999.0023] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Precise control of transgene expression would markedly facilitate certain applications of gene therapy. To regulate expression of a transferred gene in response to an exogenous compound in vivo, we modified the ecdysone-responsive system. We combined the advantages of the Drosophila (DmEcR) and the Bombyx ecdysone receptor (BmEcR) by creating a chimeric Drosophila/Bombyx ecdysone receptor (DB-EcR) that preserved the ability to bind to the modified ecdysone promoter without exogenous retinoid X receptor (RXR). In cultured cells, DB-EcR effectively mediates ligand-dependent transactivation of a reporter gene at lower concentrations of the chemical ecdysone agonist GS-E than VgRXR (DmEcR + RXR). Transgene delivery in vivo was achieved by intramyocardial injection of recombinant adenovirus vectors in adult rats. Upon stimulation with GS-E, DB-EcR potently (>40-fold induction) activated gene expression in vivo while VgRXR was not induced. This hybrid ecdysone receptor represents an important new tool for in vivo transgene regulation with potentially diverse applications in somatic and germline transfer.
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Affiliation(s)
- U C Hoppe
- Institute for Molecular Cardiobiology, Johns Hopkins University, Baltimore, Maryland 21205, USA
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48
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Promises and Limitations of Transgenic and Knockout Mice in Modeling Psychiatric Symptoms. CONTEMPORARY ISSUES IN MODELING PSYCHOPATHOLOGY 2000. [DOI: 10.1007/978-1-4757-4860-4_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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49
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50
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Shin MK, Levorse JM, Ingram RS, Tilghman SM. The temporal requirement for endothelin receptor-B signalling during neural crest development. Nature 1999; 402:496-501. [PMID: 10591209 DOI: 10.1038/990040] [Citation(s) in RCA: 257] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Endothelin receptor B (EDNRB) is a G-protein-coupled receptor with seven transmembrane domains which is required for the development of melanocytes and enteric neurons. Mice that are homozygous for a null mutation in the Ednrb gene are almost completely white and die as juveniles from megacolon. To determine when EDNRB signalling is required during embryogenesis, we have exploited the tetracycline-inducible system to generate strains of mice in which the endogenous Ednrb locus is under the control of the tetracycline-dependant transactivators tTa or rtTA. By using this system to express Ednrb at different stages of embryogenesis, we have determined that EDNRB is required during a restricted period of neural crest development between embryonic days 10 and 12.5. Moreover, our results imply that EDNRB is required for the migration of both melanoblasts and enteric neuroblasts.
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Affiliation(s)
- M K Shin
- Howard Hughes Medical Institute and Department of Molecular Biology, Princeton University, New Jersey 08544, USA
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