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CRISPR/Cas9-mediated gene knockout in the mouse brain using in utero electroporation. Sci Rep 2016; 6:20611. [PMID: 26857612 PMCID: PMC4746659 DOI: 10.1038/srep20611] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 01/08/2016] [Indexed: 01/23/2023] Open
Abstract
The CRISPR/Cas9 system has recently been adapted for generating knockout mice to investigate physiological functions and pathological mechanisms. Here, we report a highly efficient procedure for brain-specific disruption of genes of interest in vivo. We constructed pX330 plasmids expressing humanized Cas9 and single-guide RNAs (sgRNAs) against the Satb2 gene, which encodes an AT-rich DNA-binding transcription factor and is responsible for callosal axon projections in the developing mouse brain. We first confirmed that these constructs efficiently induced double-strand breaks (DSBs) in target sites of exogenous plasmids both in vitro and in vivo. We then found that the introduction of pX330-Satb2 into the developing mouse brain using in utero electroporation led to a dramatic reduction of Satb2 expression in the transfected cerebral cortex, suggesting DSBs had occurred in the Satb2 gene with high efficiency. Furthermore, we found that Cas9-mediated targeting of the Satb2 gene induced abnormalities in axonal projection patterns, which is consistent with the phenotypes previously observed in Satb2 mutant mice. Introduction of pX330-NeuN using our procedure also resulted in the efficient disruption of the NeuN gene. Thus, our procedure combining the CRISPR/Cas9 system and in utero electroporation is an effective and rapid approach to achieve brain-specific gene knockout in vivo.
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Pathophysiological analyses of cortical malformation using gyrencephalic mammals. Sci Rep 2015; 5:15370. [PMID: 26482531 PMCID: PMC4613358 DOI: 10.1038/srep15370] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 09/23/2015] [Indexed: 12/12/2022] Open
Abstract
One of the most prominent features of the cerebral cortex of higher mammals is the presence of gyri. Because malformations of the cortical gyri are associated with severe disability in brain function, the mechanisms underlying malformations of the cortical gyri have been of great interest. Combining gyrencephalic carnivore ferrets and genetic manipulations using in utero electroporation, here we successfully recapitulated the cortical phenotypes of thanatophoric dysplasia (TD) by expressing fibroblast growth factor 8 in the ferret cerebral cortex. Strikingly, in contrast to TD mice, our TD ferret model showed not only megalencephaly but also polymicrogyria. We further uncovered that outer radial glial cells (oRGs) and intermediate progenitor cells (IPs) were markedly increased. Because it has been proposed that increased oRGs and/or IPs resulted in the appearance of cortical gyri during evolution, it seemed possible that increased oRGs and IPs underlie the pathogenesis of polymicrogyria. Our findings should help shed light on the molecular mechanisms underlying the formation and malformation of cortical gyri in higher mammals.
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Okamoto M, Shinoda T, Kawaue T, Nagasaka A, Miyata T. Ferret-mouse differences in interkinetic nuclear migration and cellular densification in the neocortical ventricular zone. Neurosci Res 2015; 86:88-95. [PMID: 24780233 DOI: 10.1016/j.neures.2014.10.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Revised: 01/23/2014] [Accepted: 02/28/2014] [Indexed: 11/19/2022]
Abstract
The thick outer subventricular zone (OSVZ) is characteristic of the development of human neocortex. How this region originates from the ventricular zone (VZ) is largely unknown. Recently, we showed that over-proliferation-induced acute nuclear densification and thickening of the VZ in neocortical walls of mice, which lack an OSVZ, causes reactive delamination of undifferentiated progenitors and invasion by these cells of basal areas outside the VZ. In this study, we sought to determine how VZ cells behave in non-rodent animals that have an OSVZ. A comparison of mid-embryonic mice and ferrets revealed: (1) the VZ is thicker and more pseudostratified in ferrets. (2) The soma and nuclei of VZ cells were horizontally and apicobasally denser in ferrets. (3) Individual endfeet were also denser on the apical (ventricular) surface in ferrets. (4) In ferrets, apicalward nucleokinesis was less directional, whereas basalward nucleokinesis was more directional; consequently, the nuclear density in the periventricular space (within 16 μm of the apical surface) was smaller in ferrets than in mice, despite the nuclear densification seen basally in ferrets. These results suggest that species-specific differences in nucleokinesis strategies may have evolved in close association with the magnitudes and patterns of nuclear stratification in the VZ.
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Empie K, Rangarajan V, Juul SE. Is the ferret a suitable species for studying perinatal brain injury? Int J Dev Neurosci 2015; 45:2-10. [PMID: 26102988 PMCID: PMC4793918 DOI: 10.1016/j.ijdevneu.2015.06.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 05/09/2015] [Accepted: 06/01/2015] [Indexed: 11/26/2022] Open
Abstract
Ferret brain architecture, composition, and development are similar to humans. Postnatal ferret brain development is comparable to that of premature infants. Ferrets have potential to model preterm and term neonatal brain injury. Ferrets may fulfill the need for an intermediate model species of neurodevelopment. Many opportunities exist to expand the use of ferrets as research subjects.
Complications of prematurity often disrupt normal brain development and/or cause direct damage to the developing brain, resulting in poor neurodevelopmental outcomes. Physiologically relevant animal models of perinatal brain injury can advance our understanding of these influences and thereby provide opportunities to develop therapies and improve long-term outcomes. While there are advantages to currently available small animal models, there are also significant drawbacks that have limited translation of research findings to humans. Large animal models such as newborn pig, sheep and nonhuman primates have complex brain development more similar to humans, but these animals are expensive, and developmental testing of sheep and piglets is limited. Ferrets (Mustela putorius furo) are born lissencephalic and undergo postnatal cortical folding to form complex gyrencephalic brains. This review examines whether ferrets might provide a novel intermediate animal model of neonatal brain disease that has the benefit of a gyrified, altricial brain in a small animal. It summarizes attributes of ferret brain growth and development that make it an appealing animal in which to model perinatal brain injury. We postulate that because of their innate characteristics, ferrets have great potential in neonatal neurodevelopmental studies.
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Affiliation(s)
- Kristen Empie
- Department of Neonatology, University of Washington, Seattle, USA
| | | | - Sandra E Juul
- Department of Neonatology, University of Washington, Seattle, USA.
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Wakimoto M, Sehara K, Ebisu H, Hoshiba Y, Tsunoda S, Ichikawa Y, Kawasaki H. Classic Cadherins Mediate Selective Intracortical Circuit Formation in the Mouse Neocortex. Cereb Cortex 2014; 25:3535-46. [PMID: 25230944 DOI: 10.1093/cercor/bhu197] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Understanding the molecular mechanisms underlying the formation of selective intracortical circuitry is one of the important questions in neuroscience research. "Barrel nets" are recently identified intracortical axonal trajectories derived from layer 2/3 neurons in layer 4 of the primary somatosensory (barrel) cortex. Axons of layer 2/3 neurons are preferentially distributed in the septal regions of layer 4 of the barrel cortex, where they show whisker-related patterns. Because cadherins have been viewed as potential candidates that mediate the formation of selective neuronal circuits, here we examined the role of cadherins in the formation of barrel nets. We disrupted the function of cadherins by expressing dominant-negative cadherin (dn-cadherin) using in utero electroporation and found that barrel nets were severely disrupted. Confocal microscopic analysis revealed that expression of dn-cadherin reduced the density of axons in septal regions in layer 4 of the barrel cortex. We also found that cadherins were important for the formation, rather than the maintenance, of barrel nets. Our results uncover an important role of cadherins in the formation of local intracortical circuitry in the neocortex.
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Affiliation(s)
- Mayu Wakimoto
- Department of Biophysical Genetics, Graduate School of Medical Sciences, Kanazawa University, Ishikawa 920-8640, Japan Brain/Liver Interface Medicine Research Center, Kanazawa University, Ishikawa 920-8640, Japan Department of Molecular and Systems Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Keisuke Sehara
- Department of Molecular and Systems Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Haruka Ebisu
- Department of Biophysical Genetics, Graduate School of Medical Sciences, Kanazawa University, Ishikawa 920-8640, Japan Brain/Liver Interface Medicine Research Center, Kanazawa University, Ishikawa 920-8640, Japan Department of Molecular and Systems Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Yoshio Hoshiba
- Department of Biophysical Genetics, Graduate School of Medical Sciences, Kanazawa University, Ishikawa 920-8640, Japan Brain/Liver Interface Medicine Research Center, Kanazawa University, Ishikawa 920-8640, Japan Department of Molecular and Systems Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Shinichi Tsunoda
- Department of Biophysical Genetics, Graduate School of Medical Sciences, Kanazawa University, Ishikawa 920-8640, Japan Brain/Liver Interface Medicine Research Center, Kanazawa University, Ishikawa 920-8640, Japan
| | - Yoshie Ichikawa
- Department of Biophysical Genetics, Graduate School of Medical Sciences, Kanazawa University, Ishikawa 920-8640, Japan Brain/Liver Interface Medicine Research Center, Kanazawa University, Ishikawa 920-8640, Japan
| | - Hiroshi Kawasaki
- Department of Biophysical Genetics, Graduate School of Medical Sciences, Kanazawa University, Ishikawa 920-8640, Japan Brain/Liver Interface Medicine Research Center, Kanazawa University, Ishikawa 920-8640, Japan Department of Molecular and Systems Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
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56
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Homman-Ludiye J, Bourne JA. Mapping arealisation of the visual cortex of non-primate species: lessons for development and evolution. Front Neural Circuits 2014; 8:79. [PMID: 25071460 PMCID: PMC4081835 DOI: 10.3389/fncir.2014.00079] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 06/19/2014] [Indexed: 01/08/2023] Open
Abstract
The integration of the visual stimulus takes place at the level of the neocortex, organized in anatomically distinct and functionally unique areas. Primates, including humans, are heavily dependent on vision, with approximately 50% of their neocortical surface dedicated to visual processing and possess many more visual areas than any other mammal, making them the model of choice to study visual cortical arealisation. However, in order to identify the mechanisms responsible for patterning the developing neocortex, specifying area identity as well as elucidate events that have enabled the evolution of the complex primate visual cortex, it is essential to gain access to the cortical maps of alternative species. To this end, species including the mouse have driven the identification of cellular markers, which possess an area-specific expression profile, the development of new tools to label connections and technological advance in imaging techniques enabling monitoring of cortical activity in a behaving animal. In this review we present non-primate species that have contributed to elucidating the evolution and development of the visual cortex. We describe the current understanding of the mechanisms supporting the establishment of areal borders during development, mainly gained in the mouse thanks to the availability of genetically modified lines but also the limitations of the mouse model and the need for alternate species.
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Affiliation(s)
- Jihane Homman-Ludiye
- Bourne Group, Australian Regenerative Medicine Institute, Monash University Clayton, VIC, Australia
| | - James A Bourne
- Bourne Group, Australian Regenerative Medicine Institute, Monash University Clayton, VIC, Australia
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57
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Kawasaki H. Molecular investigations of the brain of higher mammals using gyrencephalic carnivore ferrets. Neurosci Res 2014; 86:59-65. [PMID: 24983876 DOI: 10.1016/j.neures.2014.06.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 06/16/2014] [Accepted: 06/17/2014] [Indexed: 11/17/2022]
Abstract
The brains of mammals such as carnivores and primates contain developed structures not found in the brains of mice. Uncovering the physiological importance, developmental mechanisms and evolution of these structures using carnivores and primates would greatly contribute to our understanding of the human brain and its diseases. Although the anatomical and physiological properties of the brains of carnivores and primates have been intensively examined, molecular investigations are still limited. Recently, genetic techniques that can be applied to carnivores and primates have been explored, and molecules whose expression patterns correspond to these structures were reported. Furthermore, to investigate the functional importance of these molecules, rapid and efficient genetic manipulation methods were established by applying electroporation to gyrencephalic carnivore ferrets. In this article, I review recent advances in molecular investigations of the brains of carnivores and primates, mainly focusing on ferrets (Mustela putorius furo).
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Affiliation(s)
- Hiroshi Kawasaki
- Graduate School of Medical Sciences, Kanazawa University, Ishikawa 920-8640, Japan; Brain/Liver Interface Medicine Research Center, Kanazawa University, Ishikawa 920-8640, Japan.
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58
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Ferret–mouse differences in interkinetic nuclear migration and cellular densification in the neocortical ventricular zone. Neurosci Res 2014. [DOI: 10.1016/j.neures.2014.03.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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59
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Microinjection of membrane-impermeable molecules into single neural stem cells in brain tissue. Nat Protoc 2014; 9:1170-82. [DOI: 10.1038/nprot.2014.074] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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60
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Matsui A, Tran M, Yoshida AC, Kikuchi SS, U M, Ogawa M, Shimogori T. BTBD3 Controls Dendrite Orientation Toward Active Axons in Mammalian Neocortex. Science 2013; 342:1114-8. [DOI: 10.1126/science.1244505] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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61
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Sato T, Muroyama Y, Saito T. Inducible gene expression in postmitotic neurons by an in vivo electroporation-based tetracycline system. J Neurosci Methods 2013; 214:170-6. [PMID: 23357027 DOI: 10.1016/j.jneumeth.2013.01.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 01/09/2013] [Accepted: 01/16/2013] [Indexed: 01/05/2023]
Abstract
In vivo electroporation has been widely used to transfect foreign genes into neural progenitors and analyze the function of genes of interest in the developing nervous system. However, it has not been thoroughly examined in the conditional regulation of exogenous genes in postmitotic neurons. Here we show that the combination of in vivo electroporation and the newest version of the tetracycline (Tet)-controlled gene regulatory (Tet-On) system efficiently induced gene expression in various types of neurons in mouse embryonic and postnatal tissues. In pyramidal neurons of the cerebral cortex, tetracycline-responsive element (TRE)-driven gene expression was induced in the presence of doxycycline (Dox). The induction occurred in a dose-dependent manner. The Dox-dependent induction was also observed in cerebellar Purkinje cells and spinal cord neurons. Moreover, the TRE-driven inducible expression of mammalian Barh1 (Mbh1) mimicked the phenotype of the ubiquitous expression of Mbh1 in the spinal cord. These results indicate that the combination of the Tet-On system and in vivo electroporation is useful for analyzing gene function specifically in postmitotic neurons.
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Affiliation(s)
- Tatsuya Sato
- Department of Developmental Biology, Graduate School of Medicine, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8670, Japan
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62
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Kawasaki H, Toda T, Tanno K. In vivo genetic manipulation of cortical progenitors in gyrencephalic carnivores using in utero electroporation. Biol Open 2012; 2:95-100. [PMID: 23336081 PMCID: PMC3545273 DOI: 10.1242/bio.20123160] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Accepted: 11/07/2012] [Indexed: 12/20/2022] Open
Abstract
Brain structures such as the outer subventricular zone (OSVZ) and the inner fiber layer (IFL) in the developing cerebral cortex are especially prominent in higher mammals. However, the molecular mechanisms underlying the formation of the OSVZ are still largely unknown, mainly because genetic manipulations that can be applied to the OSVZ in higher mammals had been poorly available. Here we developed and validated a rapid and efficient genetic manipulation technique for germinal zones including the OSVZ using in utero electroporation in developing gyrencephalic carnivore ferrets. We also determined the optimal conditions for using in utero electroporation to express transgenes in germinal zones. Using our electroporation procedure, the morphology of GFP-positive cells in the OSVZ was clearly visible even without immunostaining, and multiple genes were efficiently co-expressed in the same cells. Furthermore, we uncovered that fibers, which seemed to correspond to those in the IFL of monkeys, also existed in ferrets, and were derived from newly generated cortical neurons. Our technique promises to be a powerful tool for investigating the fundamental mechanisms underlying the formation and abnormalities of the cerebral cortex in higher mammals.
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Affiliation(s)
- Hiroshi Kawasaki
- Department of Molecular and Systems Neurobiology, Graduate School of Medicine, The University of Tokyo , Bunkyo-ku, Tokyo 113-0033 , Japan ; Global COE Program "Comprehensive Center of Education and Research for Chemical Biology of the Diseases", The University of Tokyo , Bunkyo-ku, Tokyo 113-0033 , Japan
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