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Raouf Z, Steinway SN, Scheese D, Lopez CM, Duess JW, Tsuboi K, Sampah M, Klerk D, El Baassiri M, Moore H, Tragesser C, Prindle T, Wang S, Wang M, Jang HS, Fulton WB, Sodhi CP, Hackam DJ. Colitis-Induced Small Intestinal Hypomotility Is Dependent on Enteroendocrine Cell Loss in Mice. Cell Mol Gastroenterol Hepatol 2024; 18:53-70. [PMID: 38438014 PMCID: PMC11127033 DOI: 10.1016/j.jcmgh.2024.02.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/23/2024] [Accepted: 02/26/2024] [Indexed: 03/06/2024]
Abstract
BACKGROUND & AIMS The abdominal discomfort experienced by patients with colitis may be attributable in part to the presence of small intestinal dysmotility, yet mechanisms linking colonic inflammation with small-bowel motility remain largely unexplored. We hypothesize that colitis results in small intestinal hypomotility owing to a loss of enteroendocrine cells (EECs) within the small intestine that can be rescued using serotonergic-modulating agents. METHODS Male C57BL/6J mice, as well as mice that overexpress (EECOVER) or lack (EECDEL) NeuroD1+ enteroendocrine cells, were exposed to dextran sulfate sodium (DSS) colitis (2.5% or 5% for 7 days) and small intestinal motility was assessed by 70-kilodalton fluorescein isothiocyanate-dextran fluorescence transit. EEC number and differentiation were evaluated by immunohistochemistry, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling staining, and quantitative reverse-transcriptase polymerase chain reaction. Mice were treated with the 5-hydroxytryptamine receptor 4 agonist prucalopride (5 mg/kg orally, daily) to restore serotonin signaling. RESULTS DSS-induced colitis was associated with a significant small-bowel hypomotility that developed in the absence of significant inflammation in the small intestine and was associated with a significant reduction in EEC density. EEC loss occurred in conjunction with alterations in the expression of key serotonin synthesis and transporter genes, including Tph1, Ddc, and Slc6a4. Importantly, mice overexpressing EECs revealed improved small intestinal motility, whereas mice lacking EECs had worse intestinal motility when exposed to DSS. Finally, treatment of DSS-exposed mice with the 5-hydroxytryptamine receptor 4 agonist prucalopride restored small intestinal motility and attenuated colitis. CONCLUSIONS Experimental DSS colitis induces significant small-bowel dysmotility in mice owing to enteroendocrine loss that can be reversed by genetic modulation of EEC or administering serotonin analogs, suggesting novel therapeutic approaches for patients with symptomatic colitis.
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Affiliation(s)
- Zachariah Raouf
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Steve N Steinway
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Daniel Scheese
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Carla M Lopez
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Johannes W Duess
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Koichi Tsuboi
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Maame Sampah
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Daphne Klerk
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Mahmoud El Baassiri
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Hannah Moore
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Cody Tragesser
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Thomas Prindle
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Sanxia Wang
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Menghan Wang
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Hee-Seong Jang
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - William B Fulton
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Chhinder P Sodhi
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.
| | - David J Hackam
- Division of Pediatric Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.
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Bohuslavova R, Fabriciova V, Smolik O, Lebrón-Mora L, Abaffy P, Benesova S, Zucha D, Valihrach L, Berkova Z, Saudek F, Pavlinkova G. NEUROD1 reinforces endocrine cell fate acquisition in pancreatic development. Nat Commun 2023; 14:5554. [PMID: 37689751 PMCID: PMC10492842 DOI: 10.1038/s41467-023-41306-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 08/30/2023] [Indexed: 09/11/2023] Open
Abstract
NEUROD1 is a transcription factor that helps maintain a mature phenotype of pancreatic β cells. Disruption of Neurod1 during pancreatic development causes severe neonatal diabetes; however, the exact role of NEUROD1 in the differentiation programs of endocrine cells is unknown. Here, we report a crucial role of the NEUROD1 regulatory network in endocrine lineage commitment and differentiation. Mechanistically, transcriptome and chromatin landscape analyses demonstrate that Neurod1 inactivation triggers a downregulation of endocrine differentiation transcription factors and upregulation of non-endocrine genes within the Neurod1-deficient endocrine cell population, disturbing endocrine identity acquisition. Neurod1 deficiency altered the H3K27me3 histone modification pattern in promoter regions of differentially expressed genes, which resulted in gene regulatory network changes in the differentiation pathway of endocrine cells, compromising endocrine cell potential, differentiation, and functional properties.
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Affiliation(s)
- Romana Bohuslavova
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology CAS, 25250, Vestec, Czechia
| | - Valeria Fabriciova
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology CAS, 25250, Vestec, Czechia
| | - Ondrej Smolik
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology CAS, 25250, Vestec, Czechia
| | - Laura Lebrón-Mora
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology CAS, 25250, Vestec, Czechia
| | - Pavel Abaffy
- Laboratory of Gene Expression, Institute of Biotechnology CAS, 25250, Vestec, Czechia
| | - Sarka Benesova
- Laboratory of Gene Expression, Institute of Biotechnology CAS, 25250, Vestec, Czechia
| | - Daniel Zucha
- Laboratory of Gene Expression, Institute of Biotechnology CAS, 25250, Vestec, Czechia
| | - Lukas Valihrach
- Laboratory of Gene Expression, Institute of Biotechnology CAS, 25250, Vestec, Czechia
| | - Zuzana Berkova
- Diabetes Centre, Experimental Medicine Centre, Institute for Clinical and Experimental Medicine, 14021, Prague, Czechia
| | - Frantisek Saudek
- Diabetes Centre, Experimental Medicine Centre, Institute for Clinical and Experimental Medicine, 14021, Prague, Czechia
| | - Gabriela Pavlinkova
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology CAS, 25250, Vestec, Czechia.
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3
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Xu D, Zhong LT, Cheng HY, Wang ZQ, Chen XM, Feng AY, Chen WY, Chen G, Xu Y. Overexpressing NeuroD1 reprograms Müller cells into various types of retinal neurons. Neural Regen Res 2022; 18:1124-1131. [PMID: 36255002 PMCID: PMC9827787 DOI: 10.4103/1673-5374.355818] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The onset of retinal degenerative disease is often associated with neuronal loss. Therefore, how to regenerate new neurons to restore vision is an important issue. NeuroD1 is a neural transcription factor with the ability to reprogram brain astrocytes into neurons in vivo. Here, we demonstrate that in adult mice, NeuroD1 can reprogram Müller cells, the principal glial cell type in the retina, to become retinal neurons. Most strikingly, ectopic expression of NeuroD1 using two different viral vectors converted Müller cells into different cell types. Specifically, AAV7m8 GFAP681::GFP-ND1 converted Müller cells into inner retinal neurons, including amacrine cells and ganglion cells. In contrast, AAV9 GFAP104::ND1-GFP converted Müller cells into outer retinal neurons such as photoreceptors and horizontal cells, with higher conversion efficiency. Furthermore, we demonstrate that Müller cell conversion induced by AAV9 GFAP104::ND1-GFP displayed clear dose- and time-dependence. These results indicate that Müller cells in adult mice are highly plastic and can be reprogrammed into various subtypes of retinal neurons.
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Affiliation(s)
- Di Xu
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Key Laboratory of CNS Regeneration (Ministry of Education), Jinan University, Guangzhou, Guangdong Province, China
| | - Li-Ting Zhong
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Key Laboratory of CNS Regeneration (Ministry of Education), Jinan University, Guangzhou, Guangdong Province, China
| | - Hai-Yang Cheng
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Key Laboratory of CNS Regeneration (Ministry of Education), Jinan University, Guangzhou, Guangdong Province, China
| | - Zeng-Qiang Wang
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Key Laboratory of CNS Regeneration (Ministry of Education), Jinan University, Guangzhou, Guangdong Province, China
| | - Xiong-Min Chen
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Key Laboratory of CNS Regeneration (Ministry of Education), Jinan University, Guangzhou, Guangdong Province, China
| | - Ai-Ying Feng
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Key Laboratory of CNS Regeneration (Ministry of Education), Jinan University, Guangzhou, Guangdong Province, China
| | - Wei-Yi Chen
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Key Laboratory of CNS Regeneration (Ministry of Education), Jinan University, Guangzhou, Guangdong Province, China
| | - Gong Chen
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Key Laboratory of CNS Regeneration (Ministry of Education), Jinan University, Guangzhou, Guangdong Province, China,Correspondence to: Ying Xu, ; Gong Chen, .
| | - Ying Xu
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Key Laboratory of CNS Regeneration (Ministry of Education), Jinan University, Guangzhou, Guangdong Province, China,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China,Correspondence to: Ying Xu, ; Gong Chen, .
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Petitpré C, Faure L, Uhl P, Fontanet P, Filova I, Pavlinkova G, Adameyko I, Hadjab S, Lallemend F. Single-cell RNA-sequencing analysis of the developing mouse inner ear identifies molecular logic of auditory neuron diversification. Nat Commun 2022; 13:3878. [PMID: 35790771 PMCID: PMC9256748 DOI: 10.1038/s41467-022-31580-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 06/21/2022] [Indexed: 11/08/2022] Open
Abstract
Different types of spiral ganglion neurons (SGNs) are essential for auditory perception by transmitting complex auditory information from hair cells (HCs) to the brain. Here, we use deep, single cell transcriptomics to study the molecular mechanisms that govern their identity and organization in mice. We identify a core set of temporally patterned genes and gene regulatory networks that may contribute to the diversification of SGNs through sequential binary decisions and demonstrate a role for NEUROD1 in driving specification of a Ic-SGN phenotype. We also find that each trajectory of the decision tree is defined by initial co-expression of alternative subtype molecular controls followed by gradual shifts toward cell fate resolution. Finally, analysis of both developing SGN and HC types reveals cell-cell signaling potentially playing a role in the differentiation of SGNs. Our results indicate that SGN identities are drafted prior to birth and reveal molecular principles that shape their differentiation and will facilitate studies of their development, physiology, and dysfunction.
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Affiliation(s)
- Charles Petitpré
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Louis Faure
- Department of Neuroimmunology, Center for Brain Research, Medical University Vienna, 1090, Vienna, Austria
| | - Phoebe Uhl
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Paula Fontanet
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Iva Filova
- Institute of Biotechnology CAS, 25250, Vestec, Czech Republic
| | | | - Igor Adameyko
- Department of Neuroimmunology, Center for Brain Research, Medical University Vienna, 1090, Vienna, Austria
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Saida Hadjab
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
| | - Francois Lallemend
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
- Ming-Wai Lau Centre for Reparative Medicine, Stockholm Node, Karolinska Institutet, Stockholm, Sweden.
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Filova I, Bohuslavova R, Tavakoli M, Yamoah EN, Fritzsch B, Pavlinkova G. Early Deletion of Neurod1 Alters Neuronal Lineage Potential and Diminishes Neurogenesis in the Inner Ear. Front Cell Dev Biol 2022; 10:845461. [PMID: 35252209 PMCID: PMC8894106 DOI: 10.3389/fcell.2022.845461] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 01/25/2022] [Indexed: 11/13/2022] Open
Abstract
Neuronal development in the inner ear is initiated by expression of the proneural basic Helix-Loop-Helix (bHLH) transcription factor Neurogenin1 that specifies neuronal precursors in the otocyst. The initial specification of the neuroblasts within the otic epithelium is followed by the expression of an additional bHLH factor, Neurod1. Although NEUROD1 is essential for inner ear neuronal development, the different aspects of the temporal and spatial requirements of NEUROD1 for the inner ear and, mainly, for auditory neuron development are not fully understood. In this study, using Foxg1Cre for the early elimination of Neurod1 in the mouse otocyst, we showed that Neurod1 deletion results in a massive reduction of differentiating neurons in the otic ganglion at E10.5, and in the diminished vestibular and rudimental spiral ganglia at E13.5. Attenuated neuronal development was associated with reduced and disorganized sensory epithelia, formation of ectopic hair cells, and the shortened cochlea in the inner ear. Central projections of inner ear neurons with conditional Neurod1 deletion are reduced, unsegregated, disorganized, and interconnecting the vestibular and auditory systems. In line with decreased afferent input from auditory neurons, the volume of cochlear nuclei was reduced by 60% in Neurod1 mutant mice. Finally, our data demonstrate that early elimination of Neurod1 affects the neuronal lineage potential and alters the generation of inner ear neurons and cochlear afferents with a profound effect on the first auditory nuclei, the cochlear nuclei.
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Affiliation(s)
- Iva Filova
- Laboratory of Molecular Pathogenesis, Institute of Biotechnology CAS, Vestec, Czechia
| | - Romana Bohuslavova
- Laboratory of Molecular Pathogenesis, Institute of Biotechnology CAS, Vestec, Czechia
| | - Mitra Tavakoli
- Laboratory of Molecular Pathogenesis, Institute of Biotechnology CAS, Vestec, Czechia
| | - Ebenezer N. Yamoah
- Department of Physiology and Cell Biology, Institute for Neuroscience, University of Nevada, Reno, NV, United States
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, IA, United States
| | - Gabriela Pavlinkova
- Laboratory of Molecular Pathogenesis, Institute of Biotechnology CAS, Vestec, Czechia
- *Correspondence: Gabriela Pavlinkova,
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6
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Bohuslavova R, Smolik O, Malfatti J, Berkova Z, Novakova Z, Saudek F, Pavlinkova G. NEUROD1 Is Required for the Early α and β Endocrine Differentiation in the Pancreas. Int J Mol Sci 2021; 22:6713. [PMID: 34201511 PMCID: PMC8268837 DOI: 10.3390/ijms22136713] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 11/17/2022] Open
Abstract
Diabetes is a metabolic disease that involves the death or dysfunction of the insulin-secreting β cells in the pancreas. Consequently, most diabetes research is aimed at understanding the molecular and cellular bases of pancreatic development, islet formation, β-cell survival, and insulin secretion. Complex interactions of signaling pathways and transcription factor networks regulate the specification, growth, and differentiation of cell types in the developing pancreas. Many of the same regulators continue to modulate gene expression and cell fate of the adult pancreas. The transcription factor NEUROD1 is essential for the maturation of β cells and the expansion of the pancreatic islet cell mass. Mutations of the Neurod1 gene cause diabetes in humans and mice. However, the different aspects of the requirement of NEUROD1 for pancreas development are not fully understood. In this study, we investigated the role of NEUROD1 during the primary and secondary transitions of mouse pancreas development. We determined that the elimination of Neurod1 impairs the expression of key transcription factors for α- and β-cell differentiation, β-cell proliferation, insulin production, and islets of Langerhans formation. These findings demonstrate that the Neurod1 deletion altered the properties of α and β endocrine cells, resulting in severe neonatal diabetes, and thus, NEUROD1 is required for proper activation of the transcriptional network and differentiation of functional α and β cells.
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Affiliation(s)
- Romana Bohuslavova
- Institute of Biotechnology CAS, 25250 Vestec, Czech Republic; (R.B.); (O.S.); (J.M.); (Z.N.)
| | - Ondrej Smolik
- Institute of Biotechnology CAS, 25250 Vestec, Czech Republic; (R.B.); (O.S.); (J.M.); (Z.N.)
- Department of Cell Biology, Faculty of Science, Charles University, 12843 Prague, Czech Republic
| | - Jessica Malfatti
- Institute of Biotechnology CAS, 25250 Vestec, Czech Republic; (R.B.); (O.S.); (J.M.); (Z.N.)
- Department of Cell Biology, Faculty of Science, Charles University, 12843 Prague, Czech Republic
| | - Zuzana Berkova
- Laboratory of Pancreatic Islets, Institute for Clinical and Experimental Medicine, 14021 Prague, Czech Republic; (Z.B.); (F.S.)
| | - Zaneta Novakova
- Institute of Biotechnology CAS, 25250 Vestec, Czech Republic; (R.B.); (O.S.); (J.M.); (Z.N.)
| | - Frantisek Saudek
- Laboratory of Pancreatic Islets, Institute for Clinical and Experimental Medicine, 14021 Prague, Czech Republic; (Z.B.); (F.S.)
| | - Gabriela Pavlinkova
- Institute of Biotechnology CAS, 25250 Vestec, Czech Republic; (R.B.); (O.S.); (J.M.); (Z.N.)
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7
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Combined Atoh1 and Neurod1 Deletion Reveals Autonomous Growth of Auditory Nerve Fibers. Mol Neurobiol 2020; 57:5307-5323. [PMID: 32880858 DOI: 10.1007/s12035-020-02092-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 08/24/2020] [Indexed: 12/24/2022]
Abstract
Ear development requires the transcription factors ATOH1 for hair cell differentiation and NEUROD1 for sensory neuron development. In addition, NEUROD1 negatively regulates Atoh1 gene expression. As we previously showed that deletion of the Neurod1 gene in the cochlea results in axon guidance defects and excessive peripheral innervation of the sensory epithelium, we hypothesized that some of the innervation defects may be a result of abnormalities in NEUROD1 and ATOH1 interactions. To characterize the interdependency of ATOH1 and NEUROD1 in inner ear development, we generated a new Atoh1/Neurod1 double null conditional deletion mutant. Through careful comparison of the effects of single Atoh1 or Neurod1 gene deletion with combined double Atoh1 and Neurod1 deletion, we demonstrate that NEUROD1-ATOH1 interactions are not important for the Neurod1 null innervation phenotype. We report that neurons lacking Neurod1 can innervate the flat epithelium without any sensory hair cells or supporting cells left after Atoh1 deletion, indicating that neurons with Neurod1 deletion do not require the presence of hair cells for axon growth. Moreover, transcriptome analysis identified genes encoding axon guidance and neurite growth molecules that are dysregulated in the Neurod1 deletion mutant. Taken together, we demonstrate that much of the projections of NEUROD1-deprived inner ear sensory neurons are regulated cell-autonomously.
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8
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Romer AI, Singer RA, Sui L, Egli D, Sussel L. Murine Perinatal β-Cell Proliferation and the Differentiation of Human Stem Cell-Derived Insulin-Expressing Cells Require NEUROD1. Diabetes 2019; 68:2259-2271. [PMID: 31519700 PMCID: PMC6868472 DOI: 10.2337/db19-0117] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 09/03/2019] [Indexed: 12/13/2022]
Abstract
Inactivation of the β-cell transcription factor NEUROD1 causes diabetes in mice and humans. In this study, we uncovered novel functions of NEUROD1 during murine islet cell development and during the differentiation of human embryonic stem cells (HESCs) into insulin-producing cells. In mice, we determined that Neurod1 is required for perinatal proliferation of α- and β-cells. Surprisingly, apoptosis only makes a minor contribution to β-cell loss when Neurod1 is deleted. Inactivation of NEUROD1 in HESCs severely impaired their differentiation from pancreatic progenitors into insulin-expressing (HESC-β) cells; however, survival or proliferation was not affected at the time points analyzed. NEUROD1 was also required in HESC-β cells for the full activation of an essential β-cell transcription factor network. These data reveal conserved and distinct functions of NEUROD1 during mouse and human β-cell development and maturation, with important implications about the function of NEUROD1 in diabetes.
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Affiliation(s)
- Anthony I Romer
- Department of Genetics and Development, Columbia University, New York, NY
- Department of Pediatrics, Columbia University, New York, NY
| | - Ruth A Singer
- Department of Genetics and Development, Columbia University, New York, NY
- Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University, New York, NY
| | - Lina Sui
- Department of Pediatrics, Columbia University, New York, NY
| | - Dieter Egli
- Department of Pediatrics, Columbia University, New York, NY
| | - Lori Sussel
- Department of Genetics and Development, Columbia University, New York, NY
- Department of Pediatrics, University of Colorado Denver School of Medicine, Denver, CO
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Abstract
Cell-type-specific gene targeting with the Cre/loxP system has become an indispensable technique in experimental neuroscience, particularly for the study of late-born glial cells that make myelin. A plethora of conditional mutants and Cre-expressing mouse lines is now available to the research community that allows laboratories to readily engage in in vivo analyses of oligodendrocytes and their precursor cells. This chapter summarizes concepts and strategies in targeting myelinating glial cells in mice for mutagenesis or imaging, and provides an overview of the most important Cre driver lines successfully used in this rapidly growing field.
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Affiliation(s)
- Sandra Goebbels
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.
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NeuroD2 controls inhibitory circuit formation in the molecular layer of the cerebellum. Sci Rep 2019; 9:1448. [PMID: 30723302 PMCID: PMC6363755 DOI: 10.1038/s41598-018-37850-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 12/12/2018] [Indexed: 12/14/2022] Open
Abstract
The cerebellar cortex is involved in the control of diverse motor and non-motor functions. Its principal circuit elements are the Purkinje cells that integrate incoming excitatory and local inhibitory inputs and provide the sole output of the cerebellar cortex. However, the transcriptional control of circuit assembly in the cerebellar cortex is not well understood. Here, we show that NeuroD2, a neuronal basic helix-loop-helix (bHLH) transcription factor, promotes the postnatal survival of both granule cells and molecular layer interneurons (basket and stellate cells). However, while NeuroD2 is not essential for the integration of surviving granule cells into the excitatory circuit, it is required for the terminal differentiation of basket cells. Axons of surviving NeuroD2-deficient basket cells follow irregular trajectories and their inhibitory terminals are virtually absent from Purkinje cells in Neurod2 mutants. As a result inhibitory, but not excitatory, input to Purkinje cells is strongly reduced in the absence of NeuroD2. Together, we conclude that NeuroD2 is necessary to instruct a terminal differentiation program in basket cells that regulates targeted axon growth and inhibitory synapse formation. An imbalance of excitation and inhibition in the cerebellar cortex affecting Purkinje cell output may underlay impaired adaptive motor learning observed in Neurod2 mutants.
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Neurod1 Is Essential for the Primary Tonotopic Organization and Related Auditory Information Processing in the Midbrain. J Neurosci 2018; 39:984-1004. [PMID: 30541910 DOI: 10.1523/jneurosci.2557-18.2018] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/17/2018] [Accepted: 12/05/2018] [Indexed: 02/06/2023] Open
Abstract
Hearing depends on extracting frequency, intensity, and temporal properties from sound to generate an auditory map for acoustical signal processing. How physiology intersects with molecular specification to fine tune the developing properties of the auditory system that enable these aspects remains unclear. We made a novel conditional deletion model that eliminates the transcription factor NEUROD1 exclusively in the ear. These mice (both sexes) develop a truncated frequency range with no neuroanatomically recognizable mapping of spiral ganglion neurons onto distinct locations in the cochlea nor a cochleotopic map presenting topographically discrete projections to the cochlear nuclei. The disorganized primary cochleotopic map alters tuning properties of the inferior colliculus units, which display abnormal frequency, intensity, and temporal sound coding. At the behavioral level, animals show alterations in the acoustic startle response, consistent with altered neuroanatomical and physiological properties. We demonstrate that absence of the primary afferent topology during embryonic development leads to dysfunctional tonotopy of the auditory system. Such effects have never been investigated in other sensory systems because of the lack of comparable single gene mutation models.SIGNIFICANCE STATEMENT All sensory systems form a topographical map of neuronal projections from peripheral sensory organs to the brain. Neuronal projections in the auditory pathway are cochleotopically organized, providing a tonotopic map of sound frequencies. Primary sensory maps typically arise by molecular cues, requiring physiological refinements. Past work has demonstrated physiologic plasticity in many senses without ever molecularly undoing the specific mapping of an entire primary sensory projection. We genetically manipulated primary auditory neurons to generate a scrambled cochleotopic projection. Eliminating tonotopic representation to auditory nuclei demonstrates the inability of physiological processes to restore a tonotopic presentation of sound in the midbrain. Our data provide the first insights into the limits of physiology-mediated brainstem plasticity during the development of the auditory system.
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12
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Development of Microplatforms to Mimic the In Vivo Architecture of CNS and PNS Physiology and Their Diseases. Genes (Basel) 2018; 9:genes9060285. [PMID: 29882823 PMCID: PMC6027402 DOI: 10.3390/genes9060285] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/28/2018] [Accepted: 05/31/2018] [Indexed: 12/16/2022] Open
Abstract
Understanding the mechanisms that govern nervous tissues function remains a challenge. In vitro two-dimensional (2D) cell culture systems provide a simplistic platform to evaluate systematic investigations but often result in unreliable responses that cannot be translated to pathophysiological settings. Recently, microplatforms have emerged to provide a better approximation of the in vivo scenario with better control over the microenvironment, stimuli and structure. Advances in biomaterials enable the construction of three-dimensional (3D) scaffolds, which combined with microfabrication, allow enhanced biomimicry through precise control of the architecture, cell positioning, fluid flows and electrochemical stimuli. This manuscript reviews, compares and contrasts advances in nervous tissues-on-a-chip models and their applications in neural physiology and disease. Microplatforms used for neuro-glia interactions, neuromuscular junctions (NMJs), blood-brain barrier (BBB) and studies on brain cancer, metastasis and neurodegenerative diseases are addressed. Finally, we highlight challenges that can be addressed with interdisciplinary efforts to achieve a higher degree of biomimicry. Nervous tissue microplatforms provide a powerful tool that is destined to provide a better understanding of neural health and disease.
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Brulet R, Zhu J, Aktar M, Hsieh J, Cho KO. Mice with conditional NeuroD1 knockout display reduced aberrant hippocampal neurogenesis but no change in epileptic seizures. Exp Neurol 2017; 293:190-198. [PMID: 28427858 PMCID: PMC5503142 DOI: 10.1016/j.expneurol.2017.04.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 04/12/2017] [Accepted: 04/14/2017] [Indexed: 12/19/2022]
Abstract
Adult neurogenesis is significantly increased in the hippocampus of rodent models of temporal lobe epilepsy (TLE). These adult-generated neurons have recently been shown to play a contributing role in the development of spontaneous recurrent seizures (SRS). In order to eventually target pro-epileptic adult neurogenesis in the clinical setting, it will be important to identify molecular players involved in the control of aberrant neurogenesis after seizures. Here, we focused on NeuroD1 (ND1), a member of the bHLH family of transcription factors previously shown to play an essential role in the differentiation and maturation of adult-generated neurons in the hippocampus. Wild-type mice treated with pilocarpine to induce status epilepticus (SE) showed a significant up-regulation of NeuroD1+ immature neuroblasts located in both the granule cell layer (GCL), and ectopically localized to the hilar region of the hippocampus. As expected, conditional knockout (cKO) of NeuroD1 in Nestin-expressing stem/progenitors and their progeny led to a reduction in the number of NeuroD1+ adult-generated neurons after pilocarpine treatment compared to WT littermates. Surprisingly, there was no change in SRS in NeuroD1 cKO mice, suggesting that NeuroD1 cKO fails to reduce aberrant neurogenesis below the threshold needed to impact SRS. Consistent with this conclusion, the total number of adult-generated neurons in the pilocarpine model, especially the total number of Prox1+ hilar ectopic granule cells were unchanged after NeuroD1 cKO, suggesting strategies to reduce SRS will need to achieve a greater removal of aberrant adult-generated neurons.
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Affiliation(s)
- Rebecca Brulet
- Department of Molecular Biology and Hamon Center for Regenerative Science and Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jingfei Zhu
- Department of Molecular Biology and Hamon Center for Regenerative Science and Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Mahafuza Aktar
- Department of Molecular Biology and Hamon Center for Regenerative Science and Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jenny Hsieh
- Department of Molecular Biology and Hamon Center for Regenerative Science and Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Kyung-Ok Cho
- Department of Pharmacology, Catholic Neuroscience Institute, School of Medicine, The Catholic University of Korea, Seoul 06591, South Korea.
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Borromeo MD, Savage TK, Kollipara RK, He M, Augustyn A, Osborne JK, Girard L, Minna JD, Gazdar AF, Cobb MH, Johnson JE. ASCL1 and NEUROD1 Reveal Heterogeneity in Pulmonary Neuroendocrine Tumors and Regulate Distinct Genetic Programs. Cell Rep 2016; 16:1259-1272. [PMID: 27452466 DOI: 10.1016/j.celrep.2016.06.081] [Citation(s) in RCA: 314] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 04/25/2016] [Accepted: 06/21/2016] [Indexed: 11/18/2022] Open
Abstract
Small cell lung carcinoma (SCLC) is a high-grade pulmonary neuroendocrine tumor. The transcription factors ASCL1 and NEUROD1 play crucial roles in promoting malignant behavior and survival of human SCLC cell lines. Here, we find that ASCL1 and NEUROD1 identify heterogeneity in SCLC, bind distinct genomic loci, and regulate mostly distinct genes. ASCL1, but not NEUROD1, is present in mouse pulmonary neuroendocrine cells, and only ASCL1 is required in vivo for tumor formation in mouse models of SCLC. ASCL1 targets oncogenic genes including MYCL1, RET, SOX2, and NFIB while NEUROD1 targets MYC. ASCL1 and NEUROD1 regulate different genes that commonly contribute to neuronal function. ASCL1 also regulates multiple genes in the NOTCH pathway including DLL3. Together, ASCL1 and NEUROD1 distinguish heterogeneity in SCLC with distinct genomic landscapes and distinct gene expression programs.
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Affiliation(s)
- Mark D Borromeo
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Trisha K Savage
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Rahul K Kollipara
- McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Min He
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Alexander Augustyn
- Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jihan K Osborne
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Luc Girard
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - John D Minna
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Adi F Gazdar
- Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Melanie H Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jane E Johnson
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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15
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Complex Neurological Phenotype in Mutant Mice Lacking Tsc2 in Excitatory Neurons of the Developing Forebrain(123). eNeuro 2015; 2:eN-NWR-0046-15. [PMID: 26693177 PMCID: PMC4676199 DOI: 10.1523/eneuro.0046-15.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 09/09/2015] [Accepted: 09/14/2015] [Indexed: 11/25/2022] Open
Abstract
Mutations in the TSC1 and TSC2 genes cause tuberous sclerosis complex (TSC), a genetic disease often associated with epilepsy, intellectual disability, and autism, and characterized by the presence of anatomical malformations in the brain as well as tumors in other organs. The TSC1 and TSC2 proteins form a complex that inhibits mammalian target of rapamycin complex 1 (mTORC1) signaling. Previous animal studies demonstrated that Tsc1 or Tsc2 loss of function in the developing brain affects the intrinsic development of neural progenitor cells, neurons, or glia. However, the interplay between different cellular elements during brain development was not previously investigated. In this study, we generated a novel mutant mouse line (NEX-Tsc2) in which the Tsc2 gene is deleted specifically in postmitotic excitatory neurons of the developing forebrain. Homozygous mutant mice failed to thrive and died prematurely, whereas heterozygous mice appeared normal. Mutant mice exhibited distinct neuroanatomical abnormalities, including malpositioning of selected neuronal populations, neuronal hypertrophy, and cortical astrogliosis. Intrinsic neuronal defects correlated with increased mTORC1 signaling, whereas astrogliosis did not result from altered intrinsic signaling, since these cells were not directly affected by the gene knockout strategy. All neuronal and non-neuronal abnormalities were suppressed by continuous postnatal treatment with the mTORC1 inhibitor RAD001. The data suggest that the loss of Tsc2 and mTORC1 signaling activation in excitatory neurons not only disrupts their intrinsic development, but also disrupts the development of cortical astrocytes, likely through the mTORC1-dependent expression of abnormal signaling proteins. This work thus provides new insights into cell-autonomous and non-cell-autonomous functions of Tsc2 in brain development.
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16
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Krishnaswamy A, Yamagata M, Duan X, Hong YK, Sanes JR. Sidekick 2 directs formation of a retinal circuit that detects differential motion. Nature 2015; 524:466-470. [PMID: 26287463 PMCID: PMC4552609 DOI: 10.1038/nature14682] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Accepted: 06/22/2015] [Indexed: 12/18/2022]
Abstract
In the mammalian retina, processes of approximately 70 types of interneurons form specific synapses on roughly 30 types of retinal ganglion cells (RGCs) in a neuropil called the inner plexiform layer. Each RGC type extracts salient features from visual input, which are sent deeper into the brain for further processing. The specificity and stereotypy of synapses formed in the inner plexiform layer account for the feature-detecting ability of RGCs. Here we analyse the development and function of synapses on one mouse RGC type, called the W3B-RGC. These cells have the remarkable property of responding when the timing of the movement of a small object differs from that of the background, but not when they coincide. Such cells, known as local edge detectors or object motion sensors, can distinguish moving objects from a visual scene that is also moving. We show that W3B-RGCs receive strong and selective input from an unusual excitatory amacrine cell type known as VG3-AC (vesicular glutamate transporter 3). Both W3B-RGCs and VG3-ACs express the immunoglobulin superfamily recognition molecule sidekick 2 (Sdk2), and both loss- and gain-of-function studies indicate that Sdk2-dependent homophilic interactions are necessary for the selectivity of the connection. The Sdk2-specified synapse is essential for visual responses of W3B-RGCs: whereas bipolar cells relay visual input directly to most RGCs, the W3B-RGCs receive much of their input indirectly, via the VG3-ACs. This non-canonical circuit introduces a delay into the pathway from photoreceptors in the centre of the receptive field to W3B-RGCs, which could improve their ability to judge the synchrony of local and global motion.
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Affiliation(s)
- Arjun Krishnaswamy
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, 02138
| | - Masahito Yamagata
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, 02138
| | - Xin Duan
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, 02138
| | - Y. Kate Hong
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, 02138
| | - Joshua R. Sanes
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, 02138
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17
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Aimone JB, Li Y, Lee SW, Clemenson GD, Deng W, Gage FH. Regulation and function of adult neurogenesis: from genes to cognition. Physiol Rev 2014; 94:991-1026. [PMID: 25287858 DOI: 10.1152/physrev.00004.2014] [Citation(s) in RCA: 421] [Impact Index Per Article: 42.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Adult neurogenesis in the hippocampus is a notable process due not only to its uniqueness and potential impact on cognition but also to its localized vertical integration of different scales of neuroscience, ranging from molecular and cellular biology to behavior. This review summarizes the recent research regarding the process of adult neurogenesis from these different perspectives, with particular emphasis on the differentiation and development of new neurons, the regulation of the process by extrinsic and intrinsic factors, and their ultimate function in the hippocampus circuit. Arising from a local neural stem cell population, new neurons progress through several stages of maturation, ultimately integrating into the adult dentate gyrus network. The increased appreciation of the full neurogenesis process, from genes and cells to behavior and cognition, makes neurogenesis both a unique case study for how scales in neuroscience can link together and suggests neurogenesis as a potential target for therapeutic intervention for a number of disorders.
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Affiliation(s)
- James B Aimone
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Yan Li
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Star W Lee
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Gregory D Clemenson
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Wei Deng
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Fred H Gage
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
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18
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Regulation of Neurod1 contributes to the lineage potential of Neurogenin3+ endocrine precursor cells in the pancreas. PLoS Genet 2013; 9:e1003278. [PMID: 23408910 PMCID: PMC3567185 DOI: 10.1371/journal.pgen.1003278] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 12/12/2012] [Indexed: 12/12/2022] Open
Abstract
During pancreatic development, transcription factor cascades gradually commit precursor populations to the different endocrine cell fate pathways. Although mutational analyses have defined the functions of many individual pancreatic transcription factors, the integrative transcription factor networks required to regulate lineage specification, as well as their sites of action, are poorly understood. In this study, we investigated where and how the transcription factors Nkx2.2 and Neurod1 genetically interact to differentially regulate endocrine cell specification. In an Nkx2.2 null background, we conditionally deleted Neurod1 in the Pdx1+ pancreatic progenitor cells, the Neurog3+ endocrine progenitor cells, or the glucagon+ alpha cells. These studies determined that, in the absence of Nkx2.2 activity, removal of Neurod1 from the Pdx1+ or Neurog3+ progenitor populations is sufficient to reestablish the specification of the PP and epsilon cell lineages. Alternatively, in the absence of Nkx2.2, removal of Neurod1 from the Pdx1+ pancreatic progenitor population, but not the Neurog3+ endocrine progenitor cells, restores alpha cell specification. Subsequent in vitro reporter assays demonstrated that Nkx2.2 represses Neurod1 in alpha cells. Based on these findings, we conclude that, although Nkx2.2 and Neurod1 are both necessary to promote beta cell differentiation, Nkx2.2 must repress Neurod1 in a Pdx1+ pancreatic progenitor population to appropriately commit a subset of Neurog3+ endocrine progenitor cells to the alpha cell lineage. These results are consistent with the proposed idea that Neurog3+ endocrine progenitor cells represent a heterogeneous population of unipotent cells, each restricted to a particular endocrine lineage. Diabetes mellitus is a family of metabolic diseases that can result from either destruction or dysfunction of the insulin-producing beta cells of the pancreas. Recent studies have provided hope that generating insulin-producing cells from alternative cell sources may be a possible treatment for diabetes; this includes the observation that pancreatic glucagon-expressing alpha cells can be converted into beta cells under certain physiological or genetic conditions. Our study focuses on two essential beta cell regulatory factors, Nkx2.2 and Neurod1, and demonstrates how their genetic interactions can promote the development of other hormone-expressing cell types, including alpha cells. We determined that, while Nkx2.2 is required to activate Neurod1 to promote beta cell formation, Nkx2.2 must prevent expression of Neurod1 to allow alpha cell formation. Furthermore, the inactivation of Neurod1 must occur in the earliest pancreatic progenitors, at a stage in the differentiation process earlier than previously believed. These studies contribute to our understanding of the overlapping gene regulatory networks that specify islet cell types and identify the importance of timing and cellular context for these regulatory interactions. Furthermore, our data have broad implications regarding the manipulation of alpha cells or human pluripotent stem cells to generate insulin-producing beta cells for therapeutic purposes.
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19
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Ochocinska MJ, Muñoz EM, Veleri S, Weller JL, Coon SL, Pozdeyev N, Iuvone PM, Goebbels S, Furukawa T, Klein DC. NeuroD1 is required for survival of photoreceptors but not pinealocytes: results from targeted gene deletion studies. J Neurochem 2012; 123:44-59. [PMID: 22784109 DOI: 10.1111/j.1471-4159.2012.07870.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
NeuroD1 encodes a basic helix-loop-helix transcription factor involved in the development of neural and endocrine structures, including the retina and pineal gland. To determine the effect of NeuroD1 knockout in these tissues, a Cre/loxP recombination strategy was used to target a NeuroD1 floxed gene and generate NeuroD1 conditional knockout (cKO) mice. Tissue specificity was conferred using Cre recombinase expressed under the control of the promoter of Crx, which is selectively expressed in the pineal gland and retina. At 2 months of age, NeuroD1 cKO retinas have a dramatic reduction in rod- and cone-driven electroretinograms and contain shortened and disorganized outer segments; by 4 months, NeuroD1 cKO retinas are devoid of photoreceptors. In contrast, the NeuroD1 cKO pineal gland appears histologically normal. Microarray analysis of 2-month-old NeuroD1 cKO retina and pineal gland identified a subset of genes that were affected 2-100-fold; in addition, a small group of genes exhibit altered differential night/day expression. Included in the down-regulated genes are Aipl1, which is necessary to prevent retinal degeneration, and Ankrd33, whose protein product is selectively expressed in the outer segments. These findings suggest that NeuroD1 may act through Aipl1 and other genes to maintain photoreceptor homeostasis.
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Affiliation(s)
- Margaret J Ochocinska
- Section on Neuroendocrinology, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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20
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Jahan I, Pan N, Kersigo J, Fritzsch B. Neurod1 suppresses hair cell differentiation in ear ganglia and regulates hair cell subtype development in the cochlea. PLoS One 2010; 5:e11661. [PMID: 20661473 PMCID: PMC2908541 DOI: 10.1371/journal.pone.0011661] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Accepted: 06/23/2010] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND At least five bHLH genes regulate cell fate determination and differentiation of sensory neurons, hair cells and supporting cells in the mammalian inner ear. Cross-regulation of Atoh1 and Neurog1 results in hair cell changes in Neurog1 null mice although the nature and mechanism of the cross-regulation has not yet been determined. Neurod1, regulated by both Neurog1 and Atoh1, could be the mediator of this cross-regulation. METHODOLOGY/PRINCIPAL FINDINGS We used Tg(Pax2-Cre) to conditionally delete Neurod1 in the inner ear. Our data demonstrate for the first time that the absence of Neurod1 results in formation of hair cells within the inner ear sensory ganglia. Three cell types, neural crest derived Schwann cells and mesenchyme derived fibroblasts (neither expresses Neurod1) and inner ear derived neurons (which express Neurod1) constitute inner ear ganglia. The most parsimonious explanation is that Neurod1 suppresses the alternative fate of sensory neurons to develop as hair cells. In the absence of Neurod1, Atoh1 is expressed and differentiates cells within the ganglion into hair cells. We followed up on this effect in ganglia by demonstrating that Neurod1 also regulates differentiation of subtypes of hair cells in the organ of Corti. We show that in Neurod1 conditional null mice there is a premature expression of several genes in the apex of the developing cochlea and outer hair cells are transformed into inner hair cells. CONCLUSIONS/SIGNIFICANCE Our data suggest that the long noted cross-regulation of Atoh1 expression by Neurog1 might actually be mediated in large part by Neurod1. We suggest that Neurod1 is regulated by both Neurog1 and Atoh1 and provides a negative feedback for either gene. Through this and other feedback, Neurod1 suppresses alternate fates of neurons to differentiate as hair cells and regulates hair cell subtypes.
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Affiliation(s)
- Israt Jahan
- Department of Biology, University of Iowa, Iowa City, Iowa, United States of America
| | - Ning Pan
- Department of Biology, University of Iowa, Iowa City, Iowa, United States of America
| | - Jennifer Kersigo
- Department of Biology, University of Iowa, Iowa City, Iowa, United States of America
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, Iowa, United States of America
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21
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Jahan I, Kersigo J, Pan N, Fritzsch B. Neurod1 regulates survival and formation of connections in mouse ear and brain. Cell Tissue Res 2010; 341:95-110. [PMID: 20512592 DOI: 10.1007/s00441-010-0984-6] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 04/15/2010] [Indexed: 12/11/2022]
Abstract
The developing sensory neurons of the mammalian ear require two sequentially activated bHLH genes, Neurog1 and Neurod1, for their development. Neurons never develop in Neurog1 null mice, and most neurons die in Neurod1 null mutants, a gene upregulated by Neurog1. The surviving neurons of Neurod1 null mice are incompletely characterized in postnatal mice because of the early lethality of mutants and the possible compromising effect of the absence of insulin on peripheral neuropathies. Using Tg(Pax2-cre), we have generated a conditional deletion of floxed Neurod1 for the ear; this mouse is viable and allows us to investigate ear innervation defects of Neurod1 absence only in the ear. We have compared the defects in embryos and show an ear phenotype in conditional Neurod1 null mice comparable with the systemic Neurod1 null mouse. By studying postnatal animals, we show that Neurod1 not only is necessary for the survival of most spiral and many vestibular neurons, but is also essential for a segregated central projection of vestibular and cochlear afferents. In the absence of Neurod1 in the ear, vestibular and cochlear afferents enter the cochlear nucleus as a single mixed nerve. Neurites coming from vestibular and cochlear sensory epithelia project centrally to both cochlear and vestibular nuclei, in addition to their designated target projections. The peripheral innervation of the remaining sensory neurons is disorganized and shows collaterals of single neurons projecting to multiple endorgans, displaying no tonotopic organization of the organ of Corti or the cochlear nucleus. Pending elucidation of the molecular details for these Neurod1 functions, these data demonstrate that Neurod1 is not only a major factor for the survival of neurons but is crucial for the development of normal ear connections, both in the ear and in the central nervous system.
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Affiliation(s)
- Israt Jahan
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA 52242, USA
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22
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Gao Z, Ure K, Ables JL, Lagace DC, Nave KA, Goebbels S, Eisch AJ, Hsieh J. Neurod1 is essential for the survival and maturation of adult-born neurons. Nat Neurosci 2009; 12:1090-2. [PMID: 19701197 DOI: 10.1038/nn.2385] [Citation(s) in RCA: 336] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Accepted: 07/14/2009] [Indexed: 01/29/2023]
Abstract
The transcriptional program that controls adult neurogenesis is unknown. We generated mice with an inducible stem cell-specific deletion of Neurod1, resulting in substantially fewer newborn neurons in the hippocampus and olfactory bulb. Thus, Neurod1 is cell-intrinsically required for the survival and maturation of adult-born neurons.
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Affiliation(s)
- Zhengliang Gao
- Department of Molecular Biology and Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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23
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Pan N, Jahan I, Lee JE, Fritzsch B. Defects in the cerebella of conditional Neurod1 null mice correlate with effective Tg(Atoh1-cre) recombination and granule cell requirements for Neurod1 for differentiation. Cell Tissue Res 2009; 337:407-28. [PMID: 19609565 DOI: 10.1007/s00441-009-0826-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Accepted: 06/12/2009] [Indexed: 01/19/2023]
Abstract
Neurod1 is a crucial basic helix-loop-helix gene for most cerebellar granule cells and mediates the differentiation of these cells downstream of Atoh1-mediated proliferation of the precursors. In Neurod1 null mice, granule cells die throughout the posterior two thirds of the cerebellar cortex during development. However, Neurod1 is also necessary for pancreatic beta-cell development, and therefore Neurod1 null mice are diabetic, which potentially influences cerebellar defects. Here, we report a new Neurod1 conditional knock-out mouse model created by using a Tg(Atoh1-cre) line to eliminate Neurod1 in the cerebellar granule cell precursors. Our data confirm and extend previous work on systemic Neurod1 null mice and show that, in the central lobules, granule cells can be eradicated in the absence of Neurod1. Granule cells in the anterior lobules are partially viable and depend on as yet unknown genes, but the Purkinje cells show defects not previously recognized. Interestingly, delayed and incomplete Tg(Atoh1-cre) upregulation occurs in the most posterior lobules; this leads to near normal expression of Neurod1 with a concomitant normal differentiation of granule cells, Purkinje cells, and unipolar brush cells in lobules IX and X. Our analysis suggests that Neurod1 negatively regulates Atoh1 to ensure a rapid transition from proliferative precursors to differentiating neurons. Our data have implications for research on medulloblastoma, one of the most frequent brain tumors of children, as the results suggest that targeted overexpression of Neurod1 under Atoh1 promoter control may initiate the differentiation of these tumors.
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Affiliation(s)
- Ning Pan
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA 52242, USA
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24
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Iulianella A, Sharma M, Durnin M, Vanden Heuvel GB, Trainor PA. Cux2 (Cutl2) integrates neural progenitor development with cell-cycle progression during spinal cord neurogenesis. Development 2008; 135:729-41. [PMID: 18223201 DOI: 10.1242/dev.013276] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Neurogenesis requires the coordination of neural progenitor proliferation and differentiation with cell-cycle regulation. However, the mechanisms coordinating these distinct cellular activities are poorly understood. Here we demonstrate for the first time that a Cut-like homeodomain transcription factor family member, Cux2 (Cutl2), regulates cell-cycle progression and development of neural progenitors. Cux2 loss-of-function mouse mutants exhibit smaller spinal cords with deficits in neural progenitor development as well as in neuroblast and interneuron differentiation. These defects correlate with reduced cell-cycle progression of neural progenitors coupled with diminished Neurod and p27(Kip1) activity. Conversely, in Cux2 gain-of-function transgenic mice, the spinal cord is enlarged in association with enhanced neuroblast formation and neuronal differentiation, particularly with respect to interneurons. Furthermore, Cux2 overexpression induces high levels of Neurod and p27(Kip1). Mechanistically, we discovered through chromatin immunoprecipitation assays that Cux2 binds both the Neurod and p27(Kip1) promoters in vivo, indicating that these interactions are direct. Our results therefore show that Cux2 functions at multiple levels during spinal cord neurogenesis. Cux2 initially influences cell-cycle progression in neural progenitors but subsequently makes additional inputs through Neurod and p27(Kip1) to regulate neuroblast formation, cell-cycle exit and cell-fate determination. Thus our work defines novel roles for Cux2 as a transcription factor that integrates cell-cycle progression with neural progenitor development during spinal cord neurogenesis.
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Affiliation(s)
- Angelo Iulianella
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA
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25
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Goebbels S, Bormuth I, Bode U, Hermanson O, Schwab MH, Nave KA. Genetic targeting of principal neurons in neocortex and hippocampus of NEX-Cre mice. Genesis 2007; 44:611-21. [PMID: 17146780 DOI: 10.1002/dvg.20256] [Citation(s) in RCA: 386] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Conditional mutagenesis permits the cell type-specific analysis of gene functions in vivo. Here, we describe a mouse line that expresses Cre recombinase under control of regulatory sequences of NEX, a gene that encodes a neuronal basic helix-loop-helix (bHLH) protein. To mimic endogenous NEX expression in the dorsal telencephalon, the Cre recombinase gene was targeted into the NEX locus by homologous recombination in ES cells. The Cre expression pattern was analyzed following breeding into different lines of lacZ-indicator mice. Most prominent Cre activity was observed in neocortex and hippocampus, starting from around embryonic day 11.5. Within the dorsal telencephalon, Cre-mediated recombination marked pyramidal neurons and dentate gyrus mossy and granule cells, but was absent from proliferating neural precursors of the ventricular zone, interneurons, oligodendrocytes, and astrocytes. Additionally, we identified formerly unknown domains of NEX promoter activity in mid- and hindbrain. The NEX-Cre mouse will be a valuable tool for behavioral research and the conditional inactivation of target genes in pyramidal neurons of the dorsal telencephalon.
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Affiliation(s)
- Sandra Goebbels
- Max-Planck-Institute of Experimental Medicine, Goettingen, Germany
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Hirrlinger PG, Scheller A, Braun C, Hirrlinger J, Kirchhoff F. Temporal control of gene recombination in astrocytes by transgenic expression of the tamoxifen-inducible DNA recombinase variant CreERT2. Glia 2006; 54:11-20. [PMID: 16575885 DOI: 10.1002/glia.20342] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Inducible gene modification using the Cre/loxP system provides a valuable tool for the analysis of gene function in the active animal. GFAP-Cre transgenic mice have been developed to achieve gene recombination in astrocytes, the most abundant cells of the central nervous system, with pivotal roles during brain function and pathology. Unfortunately, these mice displayed neuronal recombination as well, since the GFAP promoter is also active in embryonic radial glia, which possess a substantial neurogenic potential. To enable the temporal control of gene deletions in astrocytes only, we generated a transgenic mouse with expression of CreERT2, a fusion protein of the DNA recombinase Cre and a mutated ligand-binding domain of the estrogen receptor, under the control of the human GFAP promoter. In offspring originating from crossbreedings of GFAP-CreERT2-transgenic mice with various Cre-sensitive reporter mice, consecutive intraperitoneal injections of tamoxifen induced genomic recombination selectively in astrocytes of almost all brain regions. In Bergmann glia, which represent the main astroglial cell population of the cerebellum, virtually all cells showed successful gene recombination. When adult mice received cortical stab wound lesions, simultaneously given tamoxifen induced substantial recombination in reactive glia adjacent to the site of injury. These transgenic GFAP-CreERT2 mice will allow the functional analysis of loxP-modified genes in astroglia of the postnatal and adult brain.
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Affiliation(s)
- Petra G Hirrlinger
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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