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Catela C, Assimacopoulos S, Chen Y, Tsioras K, Feng W, Kratsios P. The Iroquois ( Iro/Irx) homeobox genes are conserved Hox targets involved in motor neuron development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.30.596714. [PMID: 38853975 PMCID: PMC11160718 DOI: 10.1101/2024.05.30.596714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
The Iroquois (Iro/Irx) homeobox genes encode transcription factors with fundamental roles in animal development. Despite their link to various congenital conditions in humans, our understanding of Iro/Irx gene expression, function, and regulation remains incomplete. Here, we conducted a systematic expression analysis of all six mouse Irx genes in the embryonic spinal cord. We found five Irx genes (Irx1, Irx2, Irx3, Irx5, and Irx6) to be confined mostly to ventral spinal domains, offering new molecular markers for specific groups of post-mitotic motor neurons (MNs). Further, we engineered Irx2, Irx5, and Irx6 mouse mutants and uncovered essential but distinct roles for Irx2 and Irx6 in MN development. Last, we found that the highly conserved regulators of MN development across species, the HOX proteins, directly control Irx gene expression both in mouse and C. elegans MNs, critically expanding the repertoire of HOX target genes in the developing nervous system. Altogether, our study provides important insights into Iro/Irx expression and function in the developing spinal cord, and uncovers an ancient gene regulatory relationship between HOX and Iro/Irx genes.
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Affiliation(s)
- Catarina Catela
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, USA
| | - Stavroula Assimacopoulos
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, USA
| | - Yihan Chen
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, USA
| | - Konstantinos Tsioras
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, USA
| | - Weidong Feng
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, USA
| | - Paschalis Kratsios
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, USA
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2
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Dorgau B, Collin J, Rozanska A, Zerti D, Unsworth A, Crosier M, Hussain R, Coxhead J, Dhanaseelan T, Patel A, Sowden JC, FitzPatrick DR, Queen R, Lako M. Single-cell analyses reveal transient retinal progenitor cells in the ciliary margin of developing human retina. Nat Commun 2024; 15:3567. [PMID: 38670973 PMCID: PMC11053058 DOI: 10.1038/s41467-024-47933-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 04/12/2024] [Indexed: 04/28/2024] Open
Abstract
The emergence of retinal progenitor cells and differentiation to various retinal cell types represent fundamental processes during retinal development. Herein, we provide a comprehensive single cell characterisation of transcriptional and chromatin accessibility changes that underline retinal progenitor cell specification and differentiation over the course of human retinal development up to midgestation. Our lineage trajectory data demonstrate the presence of early retinal progenitors, which transit to late, and further to transient neurogenic progenitors, that give rise to all the retinal neurons. Combining single cell RNA-Seq with spatial transcriptomics of early eye samples, we demonstrate the transient presence of early retinal progenitors in the ciliary margin zone with decreasing occurrence from 8 post-conception week of human development. In retinal progenitor cells, we identified a significant enrichment for transcriptional enhanced associate domain transcription factor binding motifs, which when inhibited led to loss of cycling progenitors and retinal identity in pluripotent stem cell derived organoids.
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Affiliation(s)
- Birthe Dorgau
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Joseph Collin
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Agata Rozanska
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Darin Zerti
- Biosciences Institute, Newcastle University, Newcastle, UK
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | | | - Moira Crosier
- Biosciences Institute, Newcastle University, Newcastle, UK
| | | | | | | | - Aara Patel
- UCL Great Ormond Street Institute of Child Health and NIHR Great Ormond Street Hospital Biomedical Research Centre, University College London, London, UK
| | - Jane C Sowden
- UCL Great Ormond Street Institute of Child Health and NIHR Great Ormond Street Hospital Biomedical Research Centre, University College London, London, UK
| | - David R FitzPatrick
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
| | - Rachel Queen
- Biosciences Institute, Newcastle University, Newcastle, UK.
| | - Majlinda Lako
- Biosciences Institute, Newcastle University, Newcastle, UK.
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3
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Minařík M, Modrell MS, Gillis JA, Campbell AS, Fuller I, Lyne R, Micklem G, Gela D, Pšenička M, Baker CVH. Identification of multiple transcription factor genes potentially involved in the development of electrosensory versus mechanosensory lateral line organs. Front Cell Dev Biol 2024; 12:1327924. [PMID: 38562141 PMCID: PMC10982350 DOI: 10.3389/fcell.2024.1327924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 02/19/2024] [Indexed: 04/04/2024] Open
Abstract
In electroreceptive jawed vertebrates, embryonic lateral line placodes give rise to electrosensory ampullary organs as well as mechanosensory neuromasts. Previous reports of shared gene expression suggest that conserved mechanisms underlie electroreceptor and mechanosensory hair cell development and that electroreceptors evolved as a transcriptionally related "sister cell type" to hair cells. We previously identified only one transcription factor gene, Neurod4, as ampullary organ-restricted in the developing lateral line system of a chondrostean ray-finned fish, the Mississippi paddlefish (Polyodon spathula). The other 16 transcription factor genes we previously validated in paddlefish were expressed in both ampullary organs and neuromasts. Here, we used our published lateral line organ-enriched gene-set (arising from differential bulk RNA-seq in late-larval paddlefish), together with a candidate gene approach, to identify 25 transcription factor genes expressed in the developing lateral line system of a more experimentally tractable chondrostean, the sterlet (Acipenser ruthenus, a small sturgeon), and/or that of paddlefish. Thirteen are expressed in both ampullary organs and neuromasts, consistent with conservation of molecular mechanisms. Seven are electrosensory-restricted on the head (Irx5, Irx3, Insm1, Sp5, Satb2, Mafa and Rorc), and five are the first-reported mechanosensory-restricted transcription factor genes (Foxg1, Sox8, Isl1, Hmx2 and Rorb). However, as previously reported, Sox8 is expressed in ampullary organs as well as neuromasts in a catshark (Scyliorhinus canicula), suggesting the existence of lineage-specific differences between cartilaginous and ray-finned fishes. Overall, our results support the hypothesis that ampullary organs and neuromasts develop via largely conserved transcriptional mechanisms, and identify multiple transcription factors potentially involved in the formation of electrosensory versus mechanosensory lateral line organs.
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Affiliation(s)
- Martin Minařík
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Melinda S. Modrell
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - J. Andrew Gillis
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Alexander S. Campbell
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Isobel Fuller
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Rachel Lyne
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Gos Micklem
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - David Gela
- Faculty of Fisheries and Protection of Waters, Research Institute of Fish Culture and Hydrobiology, University of South Bohemia in České Budějovice, Vodňany, Czechia
| | - Martin Pšenička
- Faculty of Fisheries and Protection of Waters, Research Institute of Fish Culture and Hydrobiology, University of South Bohemia in České Budějovice, Vodňany, Czechia
| | - Clare V. H. Baker
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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Malik A, Jayarathna DK, Fisher M, Barbhuiya TK, Gandhi NS, Batra J. Dynamics and recognition of homeodomain containing protein-DNA complex of IRX4. Proteins 2024; 92:282-301. [PMID: 37861198 DOI: 10.1002/prot.26604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 09/15/2023] [Accepted: 09/25/2023] [Indexed: 10/21/2023]
Abstract
Iroquois Homeobox 4 (IRX4) belongs to a family of homeobox TFs having roles in embryogenesis, cell specification, and organ development. Recently, large scale genome-wide association studies and epigenetic studies have highlighted the role of IRX4 and its associated variants in prostate cancer. No studies have investigated and characterized the structural aspect of the IRX4 homeodomain and its potential to bind to DNA. The current study uses sequence analysis, homology modeling, and molecular dynamics simulations to explore IRX4 homeodomain-DNA recognition mechanisms and the role of somatic mutations affecting these interactions. Using publicly available databases, gene expression of IRX4 was found in different tissues, including prostate, heart, skin, vagina, and the protein expression was found in cancer cell lines (HCT166, HEK293), B cells, ascitic fluid, and brain. Sequence conservation of the homeodomain shed light on the importance of N- and C-terminal residues involved in DNA binding. The specificity of IRX4 homodimer bound to consensus human DNA sequence was confirmed by molecular dynamics simulations, representing the role of conserved amino acids including R145, A194, N195, S190, R198, and R199 in binding to DNA. Additional N-terminal residues like T144 and G143 were also found to have specific interactions highlighting the importance of N-terminus of the homeodomain in DNA recognition. Additionally, the effects of somatic mutations, including the conserved Arginine (R145, R198, and R199) residues on DNA binding elucidated the importance of these residues in stabilizing the protein-DNA complex. Secondary structure and hydrogen bonding analysis showed the roles of specific residues (R145, T191, A194, N195, R198, and R199) in maintaining the homogeneity of the structure and its interaction with DNA. The differences in relative binding free energies of all the mutants shed light on the structural modularity of this protein and the dynamics behind protein-DNA interaction. We also have predicted that the C-terminal sequence of the IRX4 homeodomain could act as a potential cell-penetrating peptide, emphasizing the role these small peptides could play in targeting homeobox TFs.
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Affiliation(s)
- Adil Malik
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
- Translational Research Institute, Woolloongabba, Queensland, Australia
| | - Dulari K Jayarathna
- Centre for Genomics and Personalised Health, Queensland University of Technology, Brisbane, Queensland, Australia
- School of Chemistry and Physics, Faculty of Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Mark Fisher
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
- Centre for Genomics and Personalised Health, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Tabassum Khair Barbhuiya
- Centre for Genomics and Personalised Health, Queensland University of Technology, Brisbane, Queensland, Australia
- School of Chemistry and Physics, Faculty of Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Neha S Gandhi
- Centre for Genomics and Personalised Health, Queensland University of Technology, Brisbane, Queensland, Australia
- School of Chemistry and Physics, Faculty of Science, Queensland University of Technology, Brisbane, Queensland, Australia
- Department of Computer Science and Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Udupi, Karnataka, India
| | - Jyotsna Batra
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
- Translational Research Institute, Woolloongabba, Queensland, Australia
- Centre for Genomics and Personalised Health, Queensland University of Technology, Brisbane, Queensland, Australia
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5
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Wu SR, Zoghbi HY. The Atoh1-Cre Knock-In Allele Ectopically Labels a Subpopulation of Amacrine Cells and Bipolar Cells in Mouse Retina. eNeuro 2023; 10:ENEURO.0307-23.2023. [PMID: 37923392 PMCID: PMC10626521 DOI: 10.1523/eneuro.0307-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 10/04/2023] [Accepted: 10/05/2023] [Indexed: 11/07/2023] Open
Abstract
The retina has diverse neuronal cell types derived from a common pool of retinal progenitors. Many molecular drivers, mostly transcription factors, have been identified to promote different cell fates. In Drosophila, atonal is required for specifying photoreceptors. In mice, there are two closely related atonal homologs, Atoh1 and Atoh7 While Atoh7 is known to promote the genesis of retinal ganglion cells, there is no study on the function of Atoh1 in retinal development. Here, we crossed Atoh1Cre/+ mice to mice carrying a Cre-dependent TdTomato reporter to track potential Atoh1-lineage neurons in retinas. We characterized a heterogeneous group of TdTomato+ retinal neurons that were detected at the postnatal stage, including glutamatergic amacrine cells, AII amacrine cells, and BC3b bipolar cells. Unexpectedly, we did not observe TdTomato+ retinal neurons in the mice with an Atoh1-FlpO knock-in allele and a Flp-dependent TdTomato reporter, suggesting Atoh1 is not expressed in the mouse retina. Consistent with these data, conditional removal of Atoh1 in the retina did not cause any observable phenotypes. Importantly, we did not detect Atoh1 expression in the retina at multiple ages using mice with Atoh1-GFP knock-in allele. Therefore, we conclude that Atoh1Cre/+ mice have ectopic Cre expression in the retina and that Atoh1 is not required for retinal development.
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Affiliation(s)
- Sih-Rong Wu
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030
| | - Huda Y Zoghbi
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas 77030
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6
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Chen JK, Wiedemann J, Nguyen L, Lin Z, Tahir M, Hui CC, Plikus MV, Andersen B. IRX5 promotes DNA damage repair and activation of hair follicle stem cells. Stem Cell Reports 2023; 18:1227-1243. [PMID: 37084727 PMCID: PMC10202659 DOI: 10.1016/j.stemcr.2023.03.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 03/20/2023] [Accepted: 03/21/2023] [Indexed: 04/23/2023] Open
Abstract
The molecular mechanisms allowing hair follicles to periodically activate their stem cells (HFSCs) are incompletely characterized. Here, we identify the transcription factor IRX5 as a promoter of HFSC activation. Irx5-/- mice have delayed anagen onset, with increased DNA damage and diminished HFSC proliferation. Open chromatin regions form near cell cycle progression and DNA damage repair genes in Irx5-/- HFSCs. DNA damage repair factor BRCA1 is an IRX5 downstream target. Inhibition of FGF kinase signaling partially rescues the anagen delay in Irx5-/- mice, suggesting that the Irx5-/- HFSC quiescent phenotype is partly due to failure to suppress Fgf18 expression. Interfollicular epidermal stem cells also show decreased proliferation and increased DNA damage in Irx5-/-mice. Consistent with a role for IRX5 as a promoter of DNA damage repair, we find that IRX genes are upregulated in many cancer types and that there is a correlation between IRX5 and BRCA1 expression in breast cancer.
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Affiliation(s)
- Jefferson K Chen
- Departments of Biological Chemistry and Medicine, Division of Endocrinology, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Julie Wiedemann
- Departments of Biological Chemistry and Medicine, Division of Endocrinology, School of Medicine, University of California, Irvine, Irvine, CA, USA; Mathematical, Computational and Systems Biology (MCSB) Program, University of California, Irvine, Irvine, CA, USA
| | - Ly Nguyen
- Departments of Biological Chemistry and Medicine, Division of Endocrinology, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Zhongqi Lin
- Departments of Biological Chemistry and Medicine, Division of Endocrinology, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Mahum Tahir
- Departments of Biological Chemistry and Medicine, Division of Endocrinology, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Chi-Chung Hui
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children and Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Maksim V Plikus
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Bogi Andersen
- Departments of Biological Chemistry and Medicine, Division of Endocrinology, School of Medicine, University of California, Irvine, Irvine, CA, USA.
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7
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Narwidina A, Miyazaki A, Iwata K, Kurogoushi R, Sugimoto A, Kudo Y, Kawarabayashi K, Yamakawa Y, Akazawa Y, Kitamura T, Nakagawa H, Yamaguchi-Ueda K, Hasegawa T, Yoshizaki K, Fukumoto S, Yamamoto A, Ishimaru N, Iwasaki T, Iwamoto T. Iroquois homeobox 3 regulates odontoblast proliferation and differentiation mediated by Wnt5a expression. Biochem Biophys Res Commun 2023; 650:47-54. [PMID: 36773339 DOI: 10.1016/j.bbrc.2023.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/02/2023] [Indexed: 02/09/2023]
Abstract
Iroquois homeobox (Irx) genes are TALE-class homeobox genes that are evolutionarily conserved across species and have multiple critical cellular functions in fundamental tissue development processes. Previous studies have shown that Irxs genes are expressed during tooth development. However, the precise roles of genes in teeth remain unclear. Here, we demonstrated for the first time that Irx3 is an essential molecule for the proliferation and differentiation of odontoblasts. Using cDNA synthesized from postnatal day 1 (P1) tooth germs, we examined the expression of all Irx genes (Irx1-Irx6) by RT-PCR and found that all genes except Irx4 were expressed in the tooth tissue. Irx1-Irx3 a were expressed in the dental epithelial cell line M3H1 cells, while Irx3 and Irx5 were expressed in the dental mesenchymal cell line mDP cells. Only Irx3 was expressed in both undifferentiated cell lines. Immunostaining also revealed the presence of IRX3 in the dental epithelial cells and mesenchymal condensation. Inhibition of endogenous Irx3 by siRNA blocks the proliferation and differentiation of mDP cells. Wnt3a, Wnt5a, and Bmp4 are factors involved in odontoblast differentiation and were highly expressed in mDP cells by quantitative PCR analysis. Interestingly, the expression of Wnt5a (but not Wnt3a or Bmp4) was suppressed by Irx3 siRNA. These results suggest that Irx3 plays an essential role in part through the regulation of Wnt5a expression during odontoblast proliferation and differentiation.
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Affiliation(s)
- Anrizandy Narwidina
- Department of Pediatric Dentistry, Graduate School of Oral Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan; Department of Pediatric Dentistry, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan
| | - Aya Miyazaki
- Department of Pediatric Dentistry, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan
| | - Kokoro Iwata
- Department of Pediatric Dentistry / Special Needs Dentistry, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, 113-8549, Japan
| | - Rika Kurogoushi
- Department of Pediatric Dentistry / Special Needs Dentistry, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, 113-8549, Japan
| | - Asuna Sugimoto
- Department of Pediatric Dentistry / Special Needs Dentistry, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, 113-8549, Japan
| | - Yasusei Kudo
- Department of Oral Bioscience, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan
| | - Keita Kawarabayashi
- Department of Pediatric Dentistry, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan
| | - Yoshihito Yamakawa
- Department of Pediatric Dentistry, Graduate School of Oral Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan; Department of Pediatric Dentistry, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan
| | - Yuki Akazawa
- Department of Pediatric Dentistry, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan
| | - Takamasa Kitamura
- Department of Pediatric Dentistry, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan
| | - Hiroshi Nakagawa
- Department of Pediatric Dentistry, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan
| | - Kimiko Yamaguchi-Ueda
- Department of Pediatric Dentistry, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan
| | - Tomokazu Hasegawa
- Department of Pediatric Dentistry, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan
| | - Keigo Yoshizaki
- Orthodontics and Dentofacial Orthopedics Section, Division of Oral Health, Growth and Development, Kyushu University Faculty of Dental Science, Fukuoka, 812-8582, Japan
| | - Satoshi Fukumoto
- Pediatric Dentistry Section, Division of Oral Health, Growth and Development, Kyushu University Faculty of Dental Science, Fukuoka, 812-8582, Japan
| | - Akihito Yamamoto
- Department of Tissue Regeneration, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan
| | - Naozumi Ishimaru
- Department of Oral Molecular Pathology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan
| | - Tomonori Iwasaki
- Department of Pediatric Dentistry, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8504, Japan
| | - Tsutomu Iwamoto
- Department of Pediatric Dentistry / Special Needs Dentistry, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, 113-8549, Japan.
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8
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Pahl MC, Grant SFA, Leibel RL, Stratigopoulos G. Technologies, strategies, and cautions when deconvoluting genome-wide association signals: FTO in focus. Obes Rev 2023; 24:e13558. [PMID: 36882962 DOI: 10.1111/obr.13558] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 10/08/2022] [Accepted: 01/31/2023] [Indexed: 03/09/2023]
Abstract
Genome-wide association studies have revealed a plethora of genetic variants that correlate with polygenic conditions. However, causal molecular mechanisms have proven challenging to fully define. Without such information, the associations are not physiologically useful or clinically actionable. By reviewing studies of the FTO locus in the genetic etiology of obesity, we wish to highlight advances in the field fueled by the evolution of technical and analytic strategies in assessing the molecular bases for genetic associations. Particular attention is drawn to extrapolating experimental findings from animal models and cell types to humans, as well as technical aspects used to identify long-range DNA interactions and their biological relevance with regard to the associated trait. A unifying model is proposed by which independent obesogenic pathways regulated by multiple FTO variants and genes are integrated at the primary cilium, a cellular antenna where signaling molecules that control energy balance convene.
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Affiliation(s)
- Matthew C Pahl
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Struan F A Grant
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Division of Diabetes and Endocrinology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Pediatrics, The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.,Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Rudolph L Leibel
- Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York, USA.,Naomi Berrie Diabetes Center, Columbia University Medical Center, New York, New York, USA
| | - George Stratigopoulos
- Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York, USA.,Naomi Berrie Diabetes Center, Columbia University Medical Center, New York, New York, USA
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9
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Iroquois Family Genes in Gastric Carcinogenesis: A Comprehensive Review. Genes (Basel) 2023; 14:genes14030621. [PMID: 36980893 PMCID: PMC10048635 DOI: 10.3390/genes14030621] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/24/2023] [Accepted: 02/26/2023] [Indexed: 03/06/2023] Open
Abstract
Gastric cancer (GC) is the fifth leading cause of cancer-associated death worldwide, accounting for 768,793 related deaths and 1,089,103 new cases in 2020. Despite diagnostic advances, GC is often detected in late stages. Through a systematic literature search, this study focuses on the associations between the Iroquois gene family and GC. Accumulating evidence indicates that Iroquois genes are involved in the regulation of various physiological and pathological processes, including cancer. To date, information about Iroquois genes in GC is very limited. In recent years, the expression and function of Iroquois genes examined in different models have suggested that they play important roles in cell and cancer biology, since they were identified to be related to important signaling pathways, such as wingless, hedgehog, mitogen-activated proteins, fibroblast growth factor, TGFβ, and the PI3K/Akt and NF-kB pathways. In cancer, depending on the tumor, Iroquois genes can act as oncogenes or tumor suppressor genes. However, in GC, they seem to mostly act as tumor suppressor genes and can be regulated by several mechanisms, including methylation, microRNAs and important GC-related pathogens. In this review, we provide an up-to-date review of the current knowledge regarding Iroquois family genes in GC.
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10
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Petridou E, Godinho L. Cellular and Molecular Determinants of Retinal Cell Fate. Annu Rev Vis Sci 2022; 8:79-99. [DOI: 10.1146/annurev-vision-100820-103154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The vertebrate retina is regarded as a simple part of the central nervous system (CNS) and thus amenable to investigations of the determinants of cell fate. Its five neuronal cell classes and one glial cell class all derive from a common pool of progenitors. Here we review how each cell class is generated. Retinal progenitors progress through different competence states, in each of which they generate only a small repertoire of cell classes. The intrinsic state of the progenitor is determined by the complement of transcription factors it expresses. Thus, although progenitors are multipotent, there is a bias in the types of fates they generate during any particular time window. Overlying these competence states are stochastic mechanisms that influence fate decisions. These mechanisms are determined by a weighted set of probabilities based on the abundance of a cell class in the retina. Deterministic mechanisms also operate, especially late in development, when preprogrammed progenitors solely generate specific fates.
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Affiliation(s)
- Eleni Petridou
- Institute of Neuronal Cell Biology, Technical University of Munich, Munich, Germany;,
- Graduate School of Systemic Neurosciences (GSN), Ludwig Maximilian University of Munich, Planegg-Martinsried, Germany
| | - Leanne Godinho
- Institute of Neuronal Cell Biology, Technical University of Munich, Munich, Germany;,
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11
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Gill D, Parry A, Santos F, Okkenhaug H, Todd CD, Hernando-Herraez I, Stubbs TM, Milagre I, Reik W. Multi-omic rejuvenation of human cells by maturation phase transient reprogramming. eLife 2022; 11:e71624. [PMID: 35390271 PMCID: PMC9023058 DOI: 10.7554/elife.71624] [Citation(s) in RCA: 60] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 04/06/2022] [Indexed: 11/13/2022] Open
Abstract
Ageing is the gradual decline in organismal fitness that occurs over time leading to tissue dysfunction and disease. At the cellular level, ageing is associated with reduced function, altered gene expression and a perturbed epigenome. Recent work has demonstrated that the epigenome is already rejuvenated by the maturation phase of somatic cell reprogramming, which suggests full reprogramming is not required to reverse ageing of somatic cells. Here we have developed the first "maturation phase transient reprogramming" (MPTR) method, where reprogramming factors are selectively expressed until this rejuvenation point then withdrawn. Applying MPTR to dermal fibroblasts from middle-aged donors, we found that cells temporarily lose and then reacquire their fibroblast identity, possibly as a result of epigenetic memory at enhancers and/or persistent expression of some fibroblast genes. Excitingly, our method substantially rejuvenated multiple cellular attributes including the transcriptome, which was rejuvenated by around 30 years as measured by a novel transcriptome clock. The epigenome was rejuvenated to a similar extent, including H3K9me3 levels and the DNA methylation ageing clock. The magnitude of rejuvenation instigated by MPTR appears substantially greater than that achieved in previous transient reprogramming protocols. In addition, MPTR fibroblasts produced youthful levels of collagen proteins, and showed partial functional rejuvenation of their migration speed. Finally, our work suggests that optimal time windows exist for rejuvenating the transcriptome and the epigenome. Overall, we demonstrate that it is possible to separate rejuvenation from complete pluripotency reprogramming, which should facilitate the discovery of novel anti-ageing genes and therapies.
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Affiliation(s)
- Diljeet Gill
- Epigenetics Programme, Babraham InstituteCambridgeUnited Kingdom
| | - Aled Parry
- Epigenetics Programme, Babraham InstituteCambridgeUnited Kingdom
| | - Fátima Santos
- Epigenetics Programme, Babraham InstituteCambridgeUnited Kingdom
| | | | | | | | | | - Inês Milagre
- Laboratory for Epigenetic Mechanisms/Chromosome Dynamics Lab, Instituto Gulbenkian de CiênciaOeirasPortugal
| | - Wolf Reik
- Epigenetics Programme, Babraham InstituteCambridgeUnited Kingdom
- Wellcome Trust Sanger Institute, HinxtonCambridgeUnited Kingdom
- Centre for Trophoblast Research, University of CambridgeCambridgeUnited Kingdom
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12
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Mégarbané A, Hana S, Mégarbané H, Castro C, Baulande S, Criqui A, Roëckel-Trevisiol N, Dagher C, Al-Ali MT, Desvignes JP, Mahfoud D, El-Hayek S, Delague V. Clinical and Molecular Update on the Fourth Reported Family with Hamamy Syndrome. Mol Syndromol 2021; 12:342-350. [PMID: 34899143 DOI: 10.1159/000517253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 05/18/2021] [Indexed: 11/19/2022] Open
Abstract
We report on 2 cousins, a girl and a boy, born to first-cousin Lebanese parents with Hamamy syndrome, exhibiting developmental delay, intellectual disability, severe telecanthus, abnormal ears, dentinogenesis imperfecta, and bone fragility. Whole-exome sequencing studies performed on the 2 affected individuals and one obligate carrier revealed the presence of a homozygous c.503G>A (p.Arg168His) missense mutation in IRX5 in both sibs, not reported in any other family. Review of the literature and differential diagnoses are discussed.
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Affiliation(s)
- André Mégarbané
- Department of Human Genetics, Gilbert and Rose-Marie Ghagoury School of Medicine, Lebanese American University, Byblos, Lebanon.,Institut Jérôme Lejeune, Paris, France
| | - Sayeeda Hana
- Centre for Arab Genomic Studies, Dubai, United Arab Emirates
| | - Hala Mégarbané
- Department of Dermatology, Balamand University, Saint George Hospital, Beirut, Lebanon
| | | | | | | | | | - Christel Dagher
- Department of Human Genetics, Gilbert and Rose-Marie Ghagoury School of Medicine, Lebanese American University, Byblos, Lebanon
| | | | | | - Daniel Mahfoud
- Department of Radiology, Gilbert and Rose-Marie Ghagoury School of Medicine, Lebanese American University, Byblos, Lebanon
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13
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Dou Z, Son JE, Hui CC. Irx3 and Irx5 - Novel Regulatory Factors of Postnatal Hypothalamic Neurogenesis. Front Neurosci 2021; 15:763856. [PMID: 34795556 PMCID: PMC8593166 DOI: 10.3389/fnins.2021.763856] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 10/07/2021] [Indexed: 12/27/2022] Open
Abstract
The hypothalamus is a brain region that exhibits highly conserved anatomy across vertebrate species and functions as a central regulatory hub for many physiological processes such as energy homeostasis and circadian rhythm. Neurons in the arcuate nucleus of the hypothalamus are largely responsible for sensing of peripheral signals such as leptin and insulin, and are critical for the regulation of food intake and energy expenditure. While these neurons are mainly born during embryogenesis, accumulating evidence have demonstrated that neurogenesis also occurs in postnatal-adult mouse hypothalamus, particularly in the first two postnatal weeks. This second wave of active neurogenesis contributes to the remodeling of hypothalamic neuronal populations and regulation of energy homeostasis including hypothalamic leptin sensing. Radial glia cell types, such as tanycytes, are known to act as neuronal progenitors in the postnatal mouse hypothalamus. Our recent study unveiled a previously unreported radial glia-like neural stem cell (RGL-NSC) population that actively contributes to neurogenesis in the postnatal mouse hypothalamus. We also identified Irx3 and Irx5, which encode Iroquois homeodomain-containing transcription factors, as genetic determinants regulating the neurogenic property of these RGL-NSCs. These findings are significant as IRX3 and IRX5 have been implicated in FTO-associated obesity in humans, illustrating the importance of postnatal hypothalamic neurogenesis in energy homeostasis and obesity. In this review, we summarize current knowledge regarding postnatal-adult hypothalamic neurogenesis and highlight recent findings on the radial glia-like cells that contribute to the remodeling of postnatal mouse hypothalamus. We will discuss characteristics of the RGL-NSCs and potential actions of Irx3 and Irx5 in the regulation of neural stem cells in the postnatal-adult mouse brain. Understanding the behavior and regulation of neural stem cells in the postnatal-adult hypothalamus will provide novel mechanistic insights in the control of hypothalamic remodeling and energy homeostasis.
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Affiliation(s)
- Zhengchao Dou
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Joe Eun Son
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Chi-chung Hui
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
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14
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West ER, Cepko CL. Development and diversification of bipolar interneurons in the mammalian retina. Dev Biol 2021; 481:30-42. [PMID: 34534525 DOI: 10.1016/j.ydbio.2021.09.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 08/31/2021] [Accepted: 09/13/2021] [Indexed: 12/18/2022]
Abstract
The bipolar interneurons of the mammalian retina have evolved as a diverse set of cells with distinct subtype characteristics, which reflect specialized contributions to visual circuitry. Fifteen subtypes of bipolar interneurons have been identified in the mouse retina, each with characteristic gene expression, morphology, and light responses. This review provides an overview of the developmental events that underlie the generation of the diverse bipolar cell class, summarizing the current knowledge of genetic programs that establish and maintain bipolar subtype fates, as well as the events that shape the final distribution of bipolar subtypes. With much left to be discovered, bipolar interneurons present an ideal model system for studying the interplay between cell-autonomous and non-cell-autonomous mechanisms that influence neuronal subtype development within the central nervous system.
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Affiliation(s)
- Emma R West
- Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - Constance L Cepko
- Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA.
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15
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Holdhof D, Schoof M, Al-Kershi S, Spohn M, Kresbach C, Göbel C, Hellwig M, Indenbirken D, Moreno N, Kerl K, Schüller U. Brahma-related gene 1 has time-specific roles during brain and eye development. Development 2021; 148:268382. [PMID: 34042968 DOI: 10.1242/dev.196147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 05/04/2021] [Indexed: 11/20/2022]
Abstract
During development, gene expression is tightly controlled to facilitate the generation of the diverse cell types that form the central nervous system. Brahma-related gene 1 (Brg1, also known as Smarca4) is the catalytic subunit of the SWItch/sucrose nonfermentable (SWI/SNF) chromatin remodeling complex that regulates transcription. We investigated the role of Brg1 between embryonic day 6.5 (E6.5) and E14.5 in Sox2-positive neural stem cells (NSCs). Being without major consequences at E6.5 and E14.5, loss of Brg1 between E7.5 and E12.5 resulted in the formation of rosette-like structures in the subventricular zone, as well as morphological alterations and enlargement of neural retina (NR). Additionally, Brg1-deficient cells showed decreased survival in vitro and in vivo. Furthermore, we uncovered distinct changes in gene expression upon Brg1 loss, pointing towards impaired neuron functions, especially those involving synaptic communication and altered composition of the extracellular matrix. Comparison with mice deficient for integrase interactor 1 (Ini1, also known as Smarcb1) revealed that the enlarged NR was Brg1 specific and was not caused by a general dysfunction of the SWI/SNF complex. These results suggest a crucial role for Brg1 in NSCs during brain and eye development.
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Affiliation(s)
- Dörthe Holdhof
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,Research Institute Children's Cancer Center Hamburg, 20251 Hamburg, Germany
| | - Melanie Schoof
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,Research Institute Children's Cancer Center Hamburg, 20251 Hamburg, Germany
| | - Sina Al-Kershi
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,Research Institute Children's Cancer Center Hamburg, 20251 Hamburg, Germany
| | - Michael Spohn
- Research Institute Children's Cancer Center Hamburg, 20251 Hamburg, Germany.,Bioinformatics Facility, University Medical Center, Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Catena Kresbach
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,Research Institute Children's Cancer Center Hamburg, 20251 Hamburg, Germany
| | - Carolin Göbel
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,Research Institute Children's Cancer Center Hamburg, 20251 Hamburg, Germany
| | - Malte Hellwig
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,Research Institute Children's Cancer Center Hamburg, 20251 Hamburg, Germany
| | - Daniela Indenbirken
- Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany
| | - Natalia Moreno
- Department of Pediatric Hematology and Oncology, University Children's Hospital Münster, 48149 Münster, Germany
| | - Kornelius Kerl
- Department of Pediatric Hematology and Oncology, University Children's Hospital Münster, 48149 Münster, Germany
| | - Ulrich Schüller
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.,Research Institute Children's Cancer Center Hamburg, 20251 Hamburg, Germany.,Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
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16
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Kohl S, Llavona P, Sauer A, Reuter P, Weisschuh N, Kempf M, Dehmelt FA, Arrenberg AB, Sliesoraityte I, Zrenner E, van Schooneveld MJ, Rudolph G, Kühlewein L, Wissinger B. A duplication on chromosome 16q12 affecting the IRXB gene cluster is associated with autosomal dominant cone dystrophy with early tritanopic color vision defect. Hum Mol Genet 2021; 30:1218-1229. [PMID: 33891002 PMCID: PMC8212766 DOI: 10.1093/hmg/ddab117] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/15/2021] [Accepted: 04/15/2021] [Indexed: 02/06/2023] Open
Abstract
Cone dystrophies are a rare subgroup of inherited retinal dystrophies and hallmarked by color vision defects, low or decreasing visual acuity and central vision loss, nystagmus and photophobia. Applying genome-wide linkage analysis and array comparative genome hybridization, we identified a locus for autosomal dominant cone dystrophy on chromosome 16q12 in four independent multigeneration families. The locus is defined by duplications of variable size with a smallest region of overlap of 608 kb affecting the IRXB gene cluster and encompasses the genes IRX5 and IRX6. IRX5 and IRX6 belong to the Iroquois (Iro) protein family of homeodomain-containing transcription factors involved in patterning and regionalization of embryonic tissue in vertebrates, including the eye and the retina. All patients presented with a unique progressive cone dystrophy phenotype hallmarked by early tritanopic color vision defects. We propose that the disease underlies a misregulation of the IRXB gene cluster on chromosome 16q12 and demonstrate that overexpression of Irx5a and Irx6a, the two orthologous genes in zebrafish, results in visual impairment in 5-day-old zebrafish larvae.
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Affiliation(s)
- Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany
| | - Pablo Llavona
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany
| | - Alexandra Sauer
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany
| | - Peggy Reuter
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany
| | - Nicole Weisschuh
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany
| | - Melanie Kempf
- University Eye Hospital, Centre for Ophthalmology, University of Tübingen, Universitätsklinikum Tübingen, Tübingen 72076, Germany.,Center for Rare Eye Diseases, University of Tübingen, Tübingen 72076, Germany
| | - Florian Alexander Dehmelt
- Werner Reichardt Centre for Integrative Neuroscience and Institute of Neurobiology, University of Tübingen, Tübingen 72076, Germany
| | - Aristides B Arrenberg
- Werner Reichardt Centre for Integrative Neuroscience and Institute of Neurobiology, University of Tübingen, Tübingen 72076, Germany
| | - Ieva Sliesoraityte
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany
| | - Eberhart Zrenner
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany.,Werner Reichardt Centre for Integrative Neuroscience and Institute of Neurobiology, University of Tübingen, Tübingen 72076, Germany
| | - Mary J van Schooneveld
- Department of Ophthalmology, Amsterdam University Medical Centre, Amsterdam 1100 DD, The Netherlands.,Bartiméus Diagnostic Department, Zeist, The Netherlands
| | - Günther Rudolph
- Department of Ophthalmology, University Hospital, LMU Munich, München 80336, Germany
| | - Laura Kühlewein
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany.,University Eye Hospital, Centre for Ophthalmology, University of Tübingen, Universitätsklinikum Tübingen, Tübingen 72076, Germany
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany
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17
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Lyu J, Mu X. Genetic control of retinal ganglion cell genesis. Cell Mol Life Sci 2021; 78:4417-4433. [PMID: 33782712 DOI: 10.1007/s00018-021-03814-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 02/27/2021] [Accepted: 03/18/2021] [Indexed: 12/18/2022]
Abstract
Retinal ganglion cells (RGCs) are the only projection neurons in the neural retina. They receive and integrate visual signals from upstream retinal neurons in the visual circuitry and transmit them to the brain. The function of RGCs is performed by the approximately 40 RGC types projecting to various central brain targets. RGCs are the first cell type to form during retinogenesis. The specification and differentiation of the RGC lineage is a stepwise process; a hierarchical gene regulatory network controlling the RGC lineage has been identified and continues to be elaborated. Recent studies with single-cell transcriptomics have led to unprecedented new insights into their types and developmental trajectory. In this review, we summarize our current understanding of the functions and relationships of the many regulators of the specification and differentiation of the RGC lineage. We emphasize the roles of these key transcription factors and pathways in different developmental steps, including the transition from retinal progenitor cells (RPCs) to RGCs, RGC differentiation, generation of diverse RGC types, and central projection of the RGC axons. We discuss critical issues that remain to be addressed for a comprehensive understanding of these different aspects of RGC genesis and emerging technologies, including single-cell techniques, novel genetic tools and resources, and high-throughput genome editing and screening assays, which can be leveraged in future studies.
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Affiliation(s)
- Jianyi Lyu
- Department of Ophthalmology/Ross Eye Institute, State University of New York At Buffalo, Buffalo, NY, 14203, USA
- School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China
| | - Xiuqian Mu
- Department of Ophthalmology/Ross Eye Institute, State University of New York At Buffalo, Buffalo, NY, 14203, USA.
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18
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Tao H, Lambert JP, Yung TM, Zhu M, Hahn NA, Li D, Lau K, Sturgeon K, Puviindran V, Zhang X, Gong W, Chen XX, Anderson G, Garry DJ, Henkelman RM, Sun Y, Iulianella A, Kawakami Y, Gingras AC, Hui CC, Hopyan S. IRX3/5 regulate mitotic chromatid segregation and limb bud shape. Development 2020; 147:dev.180042. [PMID: 32907847 DOI: 10.1242/dev.180042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 08/25/2020] [Indexed: 01/19/2023]
Abstract
Pattern formation is influenced by transcriptional regulation as well as by morphogenetic mechanisms that shape organ primordia, although factors that link these processes remain under-appreciated. Here we show that, apart from their established transcriptional roles in pattern formation, IRX3/5 help to shape the limb bud primordium by promoting the separation and intercalation of dividing mesodermal cells. Surprisingly, IRX3/5 are required for appropriate cell cycle progression and chromatid segregation during mitosis, possibly in a nontranscriptional manner. IRX3/5 associate with, promote the abundance of, and share overlapping functions with co-regulators of cell division such as the cohesin subunits SMC1, SMC3, NIPBL and CUX1. The findings imply that IRX3/5 coordinate early limb bud morphogenesis with skeletal pattern formation.
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Affiliation(s)
- Hirotaka Tao
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Jean-Philippe Lambert
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON M5G 1X5, Canada
| | - Theodora M Yung
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Min Zhu
- Department of Mechanical and Industrial Engineering, University of Toronto, ON M5S 3G8, Canada
| | - Noah A Hahn
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Danyi Li
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Kimberly Lau
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Kendra Sturgeon
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Vijitha Puviindran
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Xiaoyun Zhang
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Wuming Gong
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA
| | - Xiao Xiao Chen
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Gregory Anderson
- Mouse Imaging Centre, Hospital for Sick Children, Toronto Centre for Phenogenomics, Department of Medical Biophysics, University of Toronto, Toronto, ON M5T 3H7, Canada
| | - Daniel J Garry
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA
| | - R Mark Henkelman
- Mouse Imaging Centre, Hospital for Sick Children, Toronto Centre for Phenogenomics, Department of Medical Biophysics, University of Toronto, Toronto, ON M5T 3H7, Canada
| | - Yu Sun
- Department of Mechanical and Industrial Engineering, University of Toronto, ON M5S 3G8, Canada
| | - Angelo Iulianella
- Department of Medical Neuroscience, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Yasuhiko Kawakami
- Department of Genetics, Cell Biology and Development, Stem Cell Institute, University of Minnesota, Minneapolis, MN 55455, USA
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON M5G 1X5, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Chi-Chung Hui
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada .,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Sevan Hopyan
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada .,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.,Division of Orthopaedic Surgery, Hospital for Sick Children and University of Toronto, Toronto M5G 1X8, Canada
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19
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Yin C, Ishii T, Kaneda M. Two Types of Cl Transporters Contribute to the Regulation of Intracellular Cl Concentrations in ON- and OFF-type Bipolar Cells in the Mouse Retina. Neuroscience 2020; 440:267-276. [PMID: 32531472 DOI: 10.1016/j.neuroscience.2020.06.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/28/2020] [Accepted: 06/01/2020] [Indexed: 11/29/2022]
Abstract
In the retina, ON- and OFF-type bipolar cells are classified by subtype-specific center responses, which are attributed to differences in glutamate receptor subtypes. However, the mechanisms by which ON- and OFF-type bipolar cells generate subtype-specific surround responses remain unclear. One hypothesis for surround responses is that intracellular Cl concentrations ([Cl-]i) are set at different levels to achieve opposite polarities for GABA responses in ON- and OFF-type bipolar cells. Although this hypothesis is supported by previous findings obtained from rod (ON-) type bipolar cells, there is currently no information on OFF-type bipolar cells. In the present study, we examined the distribution and function of the Cl transporters, the Na-K-Cl co-transporter (NKCC1) and K-Cl co-transporter (KCC2), in rod (ON-) and OFF-type bipolar cells using immunohistochemical, in situ hybridization, and electrophysiological methods. Rod (ON-) and OFF-type bipolar cells both expressed NKCC1 and KCC2. However, the functional contribution of NKCC1 and KCC2 to the regulation of [Cl-]i differed between rod (ON-) and OFF-type bipolar cells. Strong NKCC1 activity increased [Cl-]i in rod (ON-) type bipolar cells, while that of KCC2 decreased [Cl-]i in OFF-type bipolar cells. We also confirmed the presence of a [Cl-]i gradient between dendrites and axon terminals in rod (ON-type) bipolar cells. Thus, the subtype-specific control of [Cl-]i is achieved by the activity of NKCC1 relative to that of KCC2 and appears to influence the polarity of surround responses.
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Affiliation(s)
- Chengzhu Yin
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
| | - Toshiyuki Ishii
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan.
| | - Makoto Kaneda
- Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
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20
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VSTM2A Overexpression Is a Sensitive and Specific Biomarker for Mucinous Tubular and Spindle Cell Carcinoma (MTSCC) of the Kidney. Am J Surg Pathol 2019; 42:1571-1584. [PMID: 30285995 DOI: 10.1097/pas.0000000000001150] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Our recent study revealed recurrent chromosomal losses and somatic mutations of genes in the Hippo pathway in mucinous tubular and spindle cell carcinoma (MTSCC). Here, we performed an integrative analysis of 907 renal cell carcinoma (RCC) samples (combined from The Cancer Genome Atlas and in-house studies) and the Knepper data set of microdissected rat nephrons. We identified VSTM2A and IRX5 as novel cancer-specific and lineage-specific biomarkers in MTSCC. We then assessed their expression by RNA in situ hybridization (ISH) in 113 tumors, including 33 MTSCC, 40 type 1 papillary RCC, 8 type 2 papillary RCC, 2 unclassified RCC, 15 clear cell RCC, and 15 chromophobe RCC. Sensitivity and specificity were calculated as the area under the receiver operating characteristics curve (AUC). All MTSCC tumors demonstrated moderate to high expression of VSTM2A (mean ISH score=255). VSTM2A gene expression assessed by RNA sequencing strongly correlated with VSTM2A ISH score (r(2)=0.81, P=0.00016). The majority of non-MTSCC tumors demonstrated negative or low expression of VSTM2A. IRX5, nominated as a lineage-specific biomarker, showed moderate to high expression in MTSCC tumors (mean ISH score=140). IRX5 gene expression assessed by RNA sequencing strongly correlated with IRX5 ISH score (r(2)=0.69, P=0.00291). VSTM2A (AUC: 99.2%) demonstrated better diagnostic efficacy than IRX5 (AUC: 87.5%), and may thus serve as a potential diagnostic marker to distinguish tumors with overlapping histology. Furthermore, our results suggest MTSCC displays an overlapping phenotypic expression pattern with the loop of Henle region of normal nephrons.
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21
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Langer BE, Roscito JG, Hiller M. REforge Associates Transcription Factor Binding Site Divergence in Regulatory Elements with Phenotypic Differences between Species. Mol Biol Evol 2019; 35:3027-3040. [PMID: 30256993 PMCID: PMC6278867 DOI: 10.1093/molbev/msy187] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Elucidating the genomic determinants of morphological differences between species is key to understanding how morphological diversity evolved. While differences in cis-regulatory elements are an important genetic source for morphological evolution, it remains challenging to identify regulatory elements involved in phenotypic differences. Here, we present Regulatory Element forward genomics (REforge), a computational approach that detects associations between transcription factor binding site divergence in putative regulatory elements and phenotypic differences between species. By simulating regulatory element evolution in silico, we show that this approach has substantial power to detect such associations. To validate REforge on real data, we used known binding motifs for eye-related transcription factors and identified significant binding site divergence in vision-impaired subterranean mammals in 1% of all conserved noncoding elements. We show that these genomic regions are significantly enriched in regulatory elements that are specifically active in mouse eye tissues, and that several of them are located near genes, which are required for eye development and photoreceptor function and are implicated in human eye disorders. Thus, our genome-wide screen detects widespread divergence of eye-regulatory elements and highlights regulatory regions that likely contributed to eye degeneration in subterranean mammals. REforge has broad applicability to detect regulatory elements that could be involved in many other phenotypes, which will help to reveal the genomic basis of morphological diversity.
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Affiliation(s)
- Björn E Langer
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.,Center for Systems Biology, Dresden, Germany
| | - Juliana G Roscito
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.,Center for Systems Biology, Dresden, Germany
| | - Michael Hiller
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.,Center for Systems Biology, Dresden, Germany
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22
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Bai M, Han Y, Wu Y, Liao J, Li L, Wang L, Li Q, Xing W, Chen L, Zou W, Li J. Targeted genetic screening in mice through haploid embryonic stem cells identifies critical genes in bone development. PLoS Biol 2019; 17:e3000350. [PMID: 31265461 PMCID: PMC6629148 DOI: 10.1371/journal.pbio.3000350] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 07/15/2019] [Accepted: 06/18/2019] [Indexed: 01/23/2023] Open
Abstract
Mutagenic screening is powerful for identifying key genes involved in developmental processes. However, such screens are successful only in lower organisms. Here, we develop a targeted genetic screening approach in mice through combining androgenetic haploid embryonic stem cells (AG-haESCs) and clustered regularly interspaced palindromic repeats/CRISPR-associated protein 9 (CRISPR-Cas9) technology. We produced a mutant semi-cloned (SC) mice pool by oocyte injection of AG-haESCs carrying constitutively expressed Cas9 and an single guide RNA (sgRNA) library targeting 72 preselected genes in one step and screened for bone-development-related genes through skeletal analysis at birth. This yielded 4 genes: Zic1 and Clec11a, which are required for bone development, and Rln1 and Irx5, which had not been previously considered. Whereas Rln1-/- mice exhibited small skeletal size only at birth, Irx5-/- mice showed skeletal abnormalities both in postnatal and adult phases due to decreased bone mass and increased bone marrow adipogenesis. Mechanistically, iroquois homeobox 5 (IRX5) promotes osteoblastogenesis and inhibits adipogenesis by suppressing peroxisome proliferator activated receptor γ (PPARγ) activation. Thus, AG-haESC-mediated functional mutagenic screening opens new avenues for genetic interrogation of developmental processes in mice.
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Affiliation(s)
- Meizhu Bai
- State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Yujiao Han
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Yuxuan Wu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Jiaoyang Liao
- State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Lin Li
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lijun Wang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Qing Li
- State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Wenhui Xing
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Luonan Chen
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, Shanghai Tech University, Shanghai, China
| | - Weiguo Zou
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
- * E-mail: (JL); (WZ)
| | - Jinsong Li
- State Key Laboratory of Cell Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, Shanghai Tech University, Shanghai, China
- * E-mail: (JL); (WZ)
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23
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Miksiunas R, Mobasheri A, Bironaite D. Homeobox Genes and Homeodomain Proteins: New Insights into Cardiac Development, Degeneration and Regeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1212:155-178. [PMID: 30945165 DOI: 10.1007/5584_2019_349] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cardiovascular diseases are the most common cause of human death in the developing world. Extensive evidence indicates that various toxic environmental factors and unhealthy lifestyle choices contribute to the risk, incidence and severity of cardiovascular diseases. Alterations in the genetic level of myocardium affects normal heart development and initiates pathological processes leading to various types of cardiac diseases. Homeobox genes are a large and highly specialized family of closely related genes that direct the formation of body structure, including cardiac development. Homeobox genes encode homeodomain proteins that function as transcription factors with characteristic structures that allow them to bind to DNA, regulate gene expression and subsequently control the proper physiological function of cells, tissues and organs. Mutations in homeobox genes are rare and usually lethal with evident alterations in cardiac function at or soon after the birth. Our understanding of homeobox gene family expression and function has expanded significantly during the recent years. However, the involvement of homeobox genes in the development of human and animal cardiac tissue requires further investigation. The phenotype of human congenital heart defects unveils only some aspects of human heart development. Therefore, mouse models are often used to gain a better understanding of human heart function, pathology and regeneration. In this review, we have focused on the role of homeobox genes in the development and pathology of human heart as potential tools for the future development of targeted regenerative strategies for various heart malfunctions.
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Affiliation(s)
- Rokas Miksiunas
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Ali Mobasheri
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Daiva Bironaite
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania.
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24
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Bjune JI, Haugen C, Gudbrandsen O, Nordbø OP, Nielsen HJ, Våge V, Njølstad PR, Sagen JV, Dankel SN, Mellgren G. IRX5 regulates adipocyte amyloid precursor protein and mitochondrial respiration in obesity. Int J Obes (Lond) 2018; 43:2151-2162. [PMID: 30538277 PMCID: PMC6451637 DOI: 10.1038/s41366-018-0275-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/02/2018] [Accepted: 10/28/2018] [Indexed: 12/13/2022]
Abstract
Objective A causal obesity risk variant in the FTO locus was recently shown to inhibit adipocyte thermogenesis via increased adipose expression of the homeobox transcription factors IRX3 and IRX5. However, causal effects of IRX5 on fat storage remain to be shown in vivo, and discovery of downstream mediators may open new therapeutic avenues. Methods 17 WT and 13 Irx5 knockout (KO) mice were fed low-fat control (Ctr) or high-fat (HF) diet for 10 weeks. Body weight, energy intake and fat mass were measured. Irx5-dependent gene expression was explored by transcriptome analysis of epididymal white adipose tissue (eWAT), confirmatory obesity-dependent expression in human adipocytes in vivo, and in vitro knock-down, overexpression and transcriptional activation assays. Results Irx5 knock-out mice weighed less, had diminished fat mass, and were protected from diet-induced fat accumulation. Key adipose mitochondrial genes Pparγ coactivator 1-alpha (Pgc-1α) and uncoupling protein 1 (Ucp1) were upregulated, and a gene network centered on amyloid precursor protein (App) was downregulated in adipose tissue of knock-out mice and in isolated mouse adipocytes with stable Irx5 knock-down. An APP-centered network was also enriched in isolated adipocytes from obese compared to lean humans. IRX5 overexpression increased APP promoter activity and both IRX5 and APP inhibited transactivation of PGC-1α and UCP1. Knock-down of Irx5 or App increased mitochondrial respiration in adipocytes. Conclusion Irx5-KO mice were protected from obesity and this can partially be attributed to reduced adipose App and improved mitochondrial respiration. This novel Irx5-App pathway in adipose tissue is a possible therapeutic entry point against obesity.
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Affiliation(s)
- Jan-Inge Bjune
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, 5020, Bergen, Norway.,Hormone Laboratory, Haukeland University Hospital, 5021, Bergen, Norway
| | - Christine Haugen
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, 5020, Bergen, Norway.,Hormone Laboratory, Haukeland University Hospital, 5021, Bergen, Norway
| | - Oddrun Gudbrandsen
- Department of Clinical Medicine, University of Bergen, 5020, Bergen, Norway
| | - Ole P Nordbø
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, 5020, Bergen, Norway.,Hormone Laboratory, Haukeland University Hospital, 5021, Bergen, Norway
| | - Hans J Nielsen
- Department of Surgery, Voss Hospital, 5704, Voss, Norway
| | - Villy Våge
- Department of Surgery, Voss Hospital, 5704, Voss, Norway
| | - Pål R Njølstad
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, 5020, Bergen, Norway.,Department of Pediatrics and Adolescents, Haukeland University Hospital, 5021, Bergen, Norway
| | - Jørn V Sagen
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, 5020, Bergen, Norway.,Hormone Laboratory, Haukeland University Hospital, 5021, Bergen, Norway
| | - Simon N Dankel
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, 5020, Bergen, Norway. .,Hormone Laboratory, Haukeland University Hospital, 5021, Bergen, Norway.
| | - Gunnar Mellgren
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, 5020, Bergen, Norway. .,Hormone Laboratory, Haukeland University Hospital, 5021, Bergen, Norway.
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25
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Fu A, Oberholtzer SM, Bagheri-Fam S, Rastetter RH, Holdreith C, Caceres VL, John SV, Shaw SA, Krentz KJ, Zhang X, Hui CC, Wilhelm D, Jorgensen JS. Dynamic expression patterns of Irx3 and Irx5 during germline nest breakdown and primordial follicle formation promote follicle survival in mouse ovaries. PLoS Genet 2018; 14:e1007488. [PMID: 30071018 PMCID: PMC6071956 DOI: 10.1371/journal.pgen.1007488] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 06/13/2018] [Indexed: 01/12/2023] Open
Abstract
Women and other mammalian females are born with a finite supply of oocytes that determine their reproductive lifespan. During fetal development, individual oocytes are enclosed by a protective layer of granulosa cells to form primordial follicles that will grow, mature, and eventually release the oocyte for potential fertilization. Despite the knowledge that follicles are dysfunctional and will die without granulosa cell-oocyte interactions, the mechanisms by which these cells establish communication is unknown. We previously identified that two members of the Iroquois homeobox transcription factor gene family, Irx3 and Irx5, are expressed within developing ovaries but not testes. Deletion of both factors (Irx3-Irx5EGFP/Irx3-Irx5EGFP) disrupted granulosa cell-oocyte contact during early follicle development leading to oocyte death. Thus, we hypothesized that Irx3 and Irx5 are required to develop cell-cell communication networks to maintain follicle integrity and female fertility. A series of Irx3 and Irx5 mutant mouse models were generated to assess roles for each factor. While both Irx3 and Irx5 single mutant females were subfertile, their breeding outcomes and ovary histology indicated distinct causes. Careful analysis of Irx3- and Irx5-reporter mice linked the cause of this disparity to dynamic spatio-temporal changes in their expression patterns. Both factors marked the progenitor pre-granulosa cell population in fetal ovaries. At the critical phase of germline nest breakdown and primordial follicle formation however, Irx3 and Irx5 transitioned to oocyte- and granulosa cell-specific expression respectively. Further investigation into the cause of follicle death in Irx3-Irx5EGFP/Irx3-Irx5EGFP ovaries uncovered specific defects in both granulosa cells and oocytes. Granulosa cell defects included poor contributions to basement membrane deposition and mis-localization of gap junction proteins. Granulosa cells and oocytes both presented fewer cell projections resulting in compromised cell-cell communication. Altogether, we conclude that Irx3 and Irx5 first work together to define the pregranulosa cell population of germline nests. During primordial follicle formation, they transition to oocyte- and granulosa cell-specific expression patterns where they cooperate in neighboring cells to build the foundation for follicle integrity. This foundation is left as their legacy of the essential oocyte-granulosa cell communication network that ensures and ultimately optimizes the integrity of the ovarian reserve and therefore, the female reproductive lifespan.
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Affiliation(s)
- Anqi Fu
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Sydney M. Oberholtzer
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Stefan Bagheri-Fam
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia
| | - Raphael H. Rastetter
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
| | - Claire Holdreith
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Valeria L. Caceres
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Steven V. John
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Sarah A. Shaw
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Kathleen J. Krentz
- Genome Editing and Animal Models Core, Biotechnology Center, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Xiaoyun Zhang
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children and Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Chi-chung Hui
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children and Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Dagmar Wilhelm
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia
| | - Joan S. Jorgensen
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
- * E-mail:
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26
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Suzuki-Kerr H, Iwagawa T, Sagara H, Mizota A, Suzuki Y, Watanabe S. Pivotal roles of Fezf2 in differentiation of cone OFF bipolar cells and functional maturation of cone ON bipolar cells in retina. Exp Eye Res 2018; 171:142-154. [DOI: 10.1016/j.exer.2018.03.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 03/05/2018] [Accepted: 03/16/2018] [Indexed: 10/17/2022]
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27
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Hu W, Xin Y, Zhang L, Hu J, Sun Y, Zhao Y. Iroquois Homeodomain transcription factors in ventricular conduction system and arrhythmia. Int J Med Sci 2018; 15:808-815. [PMID: 30008591 PMCID: PMC6036080 DOI: 10.7150/ijms.25140] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 04/29/2018] [Indexed: 02/05/2023] Open
Abstract
Iroquois homeobox genes, Irx, encode cardiac transcription factors, Irx1-6 in most mammals. These six transcription factors are expressed in different patterns mainly in the ventricular part of the heart. Existing researches show that Irx genes play key roles in the differentiation and development of ventricular conduction system and the establishment and maintenance of gradient expression of potassium channels, Kv4.2. Our main focus of this review is on the recent advances in the discovery of above-mentioned genes and the function of the encoding products, how Irx genes establish ventricular conduction system and regulate ventricular repolarization, how the individual and complementary functions can be verified to complement our cognition and leads to novel therapeutic approaches.
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Affiliation(s)
- Wenyu Hu
- Department of Cardiology, the First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
| | - Yanguo Xin
- Department of Cardiology, West China Hospital of Sichuan University, Chengdu, Sichuan 610041, China
| | - Lin Zhang
- Department of Cardiology, Jinqiu Hosipital Of Liaoning Province, Shenyang, Liaoning110001, China
| | - Jian Hu
- Department of Cardiology, the First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
| | - Yingxian Sun
- Department of Cardiology, the First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
| | - Yinan Zhao
- Department of Neurology, the First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, China
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28
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Dendritic stratification differs among retinal OFF bipolar cell types in the absence of rod photoreceptors. PLoS One 2017; 12:e0173455. [PMID: 28257490 PMCID: PMC5336283 DOI: 10.1371/journal.pone.0173455] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/22/2017] [Indexed: 01/09/2023] Open
Abstract
Retinal OFF bipolar cells show distinct connectivity patterns with photoreceptors in the wild-type mouse retina. Some types are cone-specific while others penetrate further through the outer plexiform layer (OPL) to contact rods in addition to cones. To explore dendritic stratification of OFF bipolar cells in the absence of rods, we made use of the 'cone-full' Nrl-/- mouse retina in which all photoreceptor precursor cells commit to a cone fate including those which would have become rods in wild-type retinas. The dendritic distribution of OFF bipolar cell types was investigated by confocal and electron microscopic imaging of immunolabeled tissue sections. The cells' dendrites formed basal contacts with cone terminals and expressed the corresponding glutamate receptor subunits at those sites, indicating putative synapses. All of the four analyzed cell populations showed distinctive patterns of vertical dendritic invasion through the OPL. This disparate behavior of dendritic extension in an environment containing only cone terminals demonstrates type-dependent specificity for dendritic outgrowth in OFF bipolar cells: rod terminals are not required for inducing dendritic extension into distal areas of the OPL.
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29
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Comprehensive Rare Variant Analysis via Whole-Genome Sequencing to Determine the Molecular Pathology of Inherited Retinal Disease. Am J Hum Genet 2017; 100:75-90. [PMID: 28041643 DOI: 10.1016/j.ajhg.2016.12.003] [Citation(s) in RCA: 312] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 11/29/2016] [Indexed: 12/22/2022] Open
Abstract
Inherited retinal disease is a common cause of visual impairment and represents a highly heterogeneous group of conditions. Here, we present findings from a cohort of 722 individuals with inherited retinal disease, who have had whole-genome sequencing (n = 605), whole-exome sequencing (n = 72), or both (n = 45) performed, as part of the NIHR-BioResource Rare Diseases research study. We identified pathogenic variants (single-nucleotide variants, indels, or structural variants) for 404/722 (56%) individuals. Whole-genome sequencing gives unprecedented power to detect three categories of pathogenic variants in particular: structural variants, variants in GC-rich regions, which have significantly improved coverage compared to whole-exome sequencing, and variants in non-coding regulatory regions. In addition to previously reported pathogenic regulatory variants, we have identified a previously unreported pathogenic intronic variant in CHM in two males with choroideremia. We have also identified 19 genes not previously known to be associated with inherited retinal disease, which harbor biallelic predicted protein-truncating variants in unsolved cases. Whole-genome sequencing is an increasingly important comprehensive method with which to investigate the genetic causes of inherited retinal disease.
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30
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Lagali PS, Medina CF, Zhao BYH, Yan K, Baker AN, Coupland SG, Tsilfidis C, Wallace VA, Picketts DJ. Retinal interneuron survival requires non-cell-autonomous Atrx activity. Hum Mol Genet 2016; 25:4787-4803. [PMID: 28173139 DOI: 10.1093/hmg/ddw306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 08/25/2016] [Accepted: 08/30/2016] [Indexed: 01/13/2023] Open
Abstract
ATRX is a chromatin remodeling protein that is mutated in several intellectual disability disorders including alpha-thalassemia/mental retardation, X-linked (ATR-X) syndrome. We previously reported the prevalence of ophthalmological defects in ATR-X syndrome patients, and accordingly we find morphological and functional visual abnormalities in a mouse model harboring a mutation occurring in ATR-X patients. The visual system abnormalities observed in these mice parallels the Atrx-null retinal phenotype characterized by interneuron defects and selective loss of amacrine and horizontal cells. The mechanisms that underlie selective neuronal vulnerability and neurodegeneration in the central nervous system upon Atrx mutation or deletion are unknown. To interrogate the cellular specificity of Atrx for its retinal neuroprotective functions, we employed a combination of temporal and lineage-restricted conditional ablation strategies to generate five different conditional knockout mouse models, and subsequently identified a non-cell-autonomous requirement for Atrx in bipolar cells for inhibitory interneuron survival in the retina. Atrx-deficient retinal bipolar cells exhibit functional, structural and molecular alterations consistent with impairments in neuronal activity and connectivity. Gene expression changes in the Atrx-null retina indicate defective synaptic structure and neuronal circuitry, suggest excitotoxic mechanisms of neurodegeneration, and demonstrate that common targets of ATRX in the forebrain and retina may contribute to similar neuropathological processes underlying cognitive impairment and visual dysfunction in ATR-X syndrome.
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Affiliation(s)
- Pamela S Lagali
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - Chantal F Medina
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - Brandon Y H Zhao
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - Keqin Yan
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - Adam N Baker
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - Stuart G Coupland
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada.,Department of Ophthalmology, University of Ottawa, Ottawa, ON K1H 8M5, Canada,,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Catherine Tsilfidis
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada.,Department of Ophthalmology, University of Ottawa, Ottawa, ON K1H 8M5, Canada,,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Valerie A Wallace
- Vision Research Division, Krembil Research Institute, Toronto, Ontario, Canada M5T 2S8,,Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON M5T 3A9, Canada
| | - David J Picketts
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada,,Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
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31
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Cardeña-Núñez S, Sánchez-Guardado LÓ, Corral-San-Miguel R, Rodríguez-Gallardo L, Marín F, Puelles L, Aroca P, Hidalgo-Sánchez M. Expression patterns of Irx genes in the developing chick inner ear. Brain Struct Funct 2016; 222:2071-2092. [PMID: 27783221 DOI: 10.1007/s00429-016-1326-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 10/14/2016] [Indexed: 10/20/2022]
Abstract
The vertebrate inner ear is a complex three-dimensional sensorial structure with auditory and vestibular functions. The molecular patterning of the developing otic epithelium creates various positional identities, consequently leading to the stereotyped specification of each neurosensory and non-sensory element of the membranous labyrinth. The Iroquois (Iro/Irx) genes, clustered in two groups (A: Irx1, Irx2, and Irx4; and B: Irx3, Irx5, and Irx6), encode for transcriptional factors involved directly in numerous patterning processes of embryonic tissues in many phyla. This work presents a detailed study of the expression patterns of these six Irx genes during chick inner ear development, paying particular attention to the axial specification of the otic anlagen. The Irx genes seem to play different roles at different embryonic periods. At the otic vesicle stage (HH18), all the genes of each cluster are expressed identically. Both clusters A and B seem involved in the specification of the lateral and posterior portions of the otic anlagen. Cluster B seems to regulate a larger area than cluster A, including the presumptive territory of the endolymphatic apparatus. Both clusters seem also to be involved in neurogenic events. At stages HH24/25-HH27, combinations of IrxA and IrxB genes participate in the specification of most sensory patches and some non-sensory components of the otic epithelium. At stage HH34, the six Irx genes show divergent patterns of expression, leading to the final specification of the membranous labyrinth, as well as to cell differentiation.
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Affiliation(s)
- Sheila Cardeña-Núñez
- Department of Cell Biology, School of Science, University of Extremadura, Avda de Elvas s/n, E06071, Badajoz, Spain
| | - Luis Óscar Sánchez-Guardado
- Department of Cell Biology, School of Science, University of Extremadura, Avda de Elvas s/n, E06071, Badajoz, Spain
| | - Rubén Corral-San-Miguel
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de La Arrixaca (IMIB-Arrixaca), E30100, Murcia, Spain
| | - Lucía Rodríguez-Gallardo
- Department of Cell Biology, School of Science, University of Extremadura, Avda de Elvas s/n, E06071, Badajoz, Spain
| | - Faustino Marín
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de La Arrixaca (IMIB-Arrixaca), E30100, Murcia, Spain
| | - Luis Puelles
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de La Arrixaca (IMIB-Arrixaca), E30100, Murcia, Spain
| | - Pilar Aroca
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de La Arrixaca (IMIB-Arrixaca), E30100, Murcia, Spain
| | - Matías Hidalgo-Sánchez
- Department of Cell Biology, School of Science, University of Extremadura, Avda de Elvas s/n, E06071, Badajoz, Spain.
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Liu D, Pattabiraman V, Bacanamwo M, Anderson LM. Iroquois homeobox transcription factor (Irx5) promotes G1/S-phase transition in vascular smooth muscle cells by CDK2-dependent activation. Am J Physiol Cell Physiol 2016; 311:C179-89. [PMID: 27170637 PMCID: PMC5129766 DOI: 10.1152/ajpcell.00293.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 05/06/2016] [Indexed: 12/30/2022]
Abstract
The Iroquois homeobox (Irx5) gene is essential in embryonic development and cardiac electrophysiology. Although recent studies have reported that IRX5 protein is involved in regulation of the cell cycle and apoptosis in prostate cancer cells, little is known about the role of IRX5 in the adult vasculature. Here we report novel observations on the role of IRX5 in adult vascular smooth muscle cells (VSMCs) during proliferation in vitro and in vivo. Comparative studies using primary human endothelial cells, VSMCs, and intact carotid arteries to determine relative expression of Irx5 in the peripheral vasculature demonstrate significantly higher expression in VSMCs. Sprague-Dawley rat carotid arteries were subjected to balloon catherization, and the presence of IRX5 was examined by immunohistochemistry after 2 wk. Results indicate markedly elevated IRX5 signal at 14 days compared with uninjured controls. Total RNA was isolated from injured and uninjured arteries, and Irx5 expression was measured by RT-PCR. Results demonstrate a significant increase in Irx5 expression at 3-14 days postinjury compared with controls. Irx5 genetic gain- and loss-of-function studies using thymidine and 5-bromo-2'-deoxyuridine incorporation assays resulted in modulation of DNA synthesis in primary rat aortic VSMCs. Quantitative RT-PCR results revealed modulation of cyclin-dependent kinase inhibitor 1B (p27(kip1)), E2F transcription factor 1 (E2f1), and proliferating cell nuclear antigen (Pcna) expression in Irx5-transduced VSMCs compared with controls. Subsequently, apoptosis was observed and confirmed by morphological observation, caspase-3 cleavage, and enzymatic activation compared with control conditions. Taken together, these results indicate that Irx5 plays an important role in VSMC G1/S-phase cell cycle checkpoint control and apoptosis.
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Affiliation(s)
- Dong Liu
- Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, Georgia; Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia; and
| | - Vaishnavi Pattabiraman
- Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, Georgia; Department of Medicine, Morehouse School of Medicine, Atlanta, Georgia
| | - Methode Bacanamwo
- Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, Georgia; Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia; and
| | - Leonard M Anderson
- Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, Georgia; Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia; and
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Transitional Progenitors during Vertebrate Retinogenesis. Mol Neurobiol 2016; 54:3565-3576. [PMID: 27194297 DOI: 10.1007/s12035-016-9899-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 05/03/2016] [Indexed: 12/13/2022]
Abstract
The retina is a delicate neural tissue responsible for light signal capturing, modulating, and passing to mid-brain. The brain then translated the signals into three-dimensional vision. The mature retina is composed of more than 50 subtypes of cells, all of which are developed from a pool of early multipotent retinal progenitors, which pass through sequential statuses of oligopotent, bipotent, and unipotent progenitors, and finally become terminally differentiated retinal cells. A transitional progenitor model is proposed here to describe how intrinsic developmental programs, along with environmental cues, control the step-by-step differentiation during retinogenesis. The model could elegantly explain many current findings as well as predict roles of intrinsic factors during retinal development.
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Vöcking O, Kourtesis I, Hausen H. Posterior eyespots in larval chitons have a molecular identity similar to anterior cerebral eyes in other bilaterians. EvoDevo 2015; 6:40. [PMID: 26702352 PMCID: PMC4689004 DOI: 10.1186/s13227-015-0036-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 11/19/2015] [Indexed: 11/17/2022] Open
Abstract
Background Development of cerebral eyes is generally based on fine-tuned networks and closely intertwined with the formation of brain and head. Consistently and best studied in insects and vertebrates, many signaling pathways relaying the activity of eye developmental factors to positional information in the head region are characterized. Though known from several organisms, photoreceptors developing outside the head region are much less studied and the course of their development, relation to cerebral eyes and evolutionary origin is in most cases unknown. To explore how position influences development of otherwise similar photoreceptors, we analyzed the molecular characteristics of photoreceptors we discovered at the very anterior, the posttrochal mid-body and posterior body region of larval Leptochiton asellus, a representative of the chiton subgroup of mollusks. Results Irrespective of their position, all found photoreceptors exhibit a molecular signature highly similar to cerebral eye photoreceptors of related animals. All photoreceptors employ the same subtype of visual pigments (r-opsin), and the same key elements for phototransduction such as GNAq, trpC and arrestin and intracellular r-opsin transport such as rip11 and myosinV as described from other protostome cerebral eyes. Several transcription factors commonly involved in cerebral eye and brain development such as six1/2, eya, dachshund, lhx2/9 and prox are also expressed by all found photoreceptor cells, only pax6 being restricted to the anterior most cells. Coexpression of pax6 and MITF in photoreceptor-associated shielding pigment cells present at the mid-body position matches the common situation in cerebral eye retinal pigment epithelium specification and differentiation. Notably, all photoreceptors, even the posterior ones, further express clear anterior markers such as foxq2, irx, otx, and six3/6 (only the latter absent in the most posterior photoreceptors), which play important roles in the early patterning of the anterior neurogenic area throughout the animal kingdom. Conclusions Our data suggest that anterior eyes with brain-associated development can indeed be subject to heterotopic replication to developmentally distinct and even posterior body regions. Retention of the transcriptional activity of a broad set of eye developmental factors and common anterior markers suggests a mode of eye development induction, which is largely independent of body regionalization. Electronic supplementary material The online version of this article (doi:10.1186/s13227-015-0036-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Oliver Vöcking
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway ; Department of Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway
| | - Ioannis Kourtesis
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway
| | - Harald Hausen
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway
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Chakraborty R, Pardue MT. Molecular and Biochemical Aspects of the Retina on Refraction. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 134:249-67. [PMID: 26310159 DOI: 10.1016/bs.pmbts.2015.06.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mutant mouse models with specific visual pathway defects offer an advantage to comprehensively investigate the role of specific pathways/neurons involved in refractive development. In this review, we will focus on recent studies using mouse models that have provided insight into retinal pathways and neurotransmitters controlling refractive development. Specifically, we will examine the contributions of rod and cone photoreceptors and the ON and OFF retinal pathways to visually driven eye growth with emphasis on dopaminergic mechanisms.
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Affiliation(s)
- Ranjay Chakraborty
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Machelle T Pardue
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia, USA.
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Transcription factor PRDM8 is required for rod bipolar and type 2 OFF-cone bipolar cell survival and amacrine subtype identity. Proc Natl Acad Sci U S A 2015; 112:E3010-9. [PMID: 26023183 DOI: 10.1073/pnas.1505870112] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Retinal bipolar (BP) cells mediate the earliest steps in image processing in the visual system, but the genetic pathways that regulate their development and function are incompletely known. We identified PRDI-BF1 and RIZ homology domain containing 8 (PRDM8) as a highly conserved transcription factor that is abundantly expressed in mouse retina. During development and in maturity, PRDM8 is expressed strongly in BP cells and a fraction of amacrine and ganglion cells. To determine whether Prdm8 is essential to BP cell development or physiology, we targeted the gene in mice. Prdm8(EGFP/EGFP) mice showed nonprogressive b-wave deficits on electroretinograms, consistent with compromised BP cell function or circuitry resembling the incomplete form of human congenital stationary night blindness (CSNB). BP cell specification was normal in Prdm8(EGFP/EGFP) retina as determined by VSX2(+) cell numbers and retinal morphology at postnatal day 6. BP subtype differentiation was impaired, however, as indicated by absent or diminished expression of BP subtype-specific markers, including the putative PRDM8 regulatory target PKCα (Prkca) and its protein. By adulthood, rod bipolar (RB) and type 2 OFF-cone bipolar (CB) cells were nearly absent from Prdm8-null mice. Although no change was detected in total amacrine cell (AC) numbers, increased PRKCA(+) and cholinergic ACs and decreased GABAergic ACs were seen, suggesting an alteration in amacrine subtype identity. These findings establish that PRDM8 is required for RB and type 2 OFF-CB cell survival and amacrine subtype identity, and they present PRDM8 as a candidate gene for human CSNB.
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Churcher AM, Pujolar JM, Milan M, Hubbard PC, Martins RST, Saraiva JL, Huertas M, Bargelloni L, Patarnello T, Marino IAM, Zane L, Canário AVM. Changes in the gene expression profiles of the brains of male European eels (Anguilla anguilla) during sexual maturation. BMC Genomics 2014; 15:799. [PMID: 25230743 PMCID: PMC4175612 DOI: 10.1186/1471-2164-15-799] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 09/11/2014] [Indexed: 12/19/2022] Open
Abstract
Background The vertebrate brain plays a critical role in the regulation of sexual maturation and reproduction by integrating environmental information with developmental and endocrine status. The European eel Anguilla anguilla is an important species in which to better understand the neuroendocrine factors that control reproduction because it is an endangered species, has a complex life cycle that includes two extreme long distance migrations with both freshwater and seawater stages and because it occupies a key position within the teleost phylogeny. At present, mature eels have never been caught in the wild and little is known about most aspects of reproduction in A. anguilla. The goal of this study was to identify genes that may be involved in sexual maturation in experimentally matured eels. For this, we used microarrays to compare the gene expression profiles of sexually mature to immature males. Results Using a false discovery rate of 0.05, a total of 1,497 differentially expressed genes were identified. Of this set, 991 were expressed at higher levels in brains (forebrain and midbrain) of mature males while 506 were expressed at lower levels relative to brains of immature males. The set of up-regulated genes includes genes involved in neuroendocrine processes, cell-cell signaling, neurogenesis and development. Interestingly, while genes involved in immune system function were down-regulated in the brains of mature males, changes in the expression levels of several receptors and channels were observed suggesting that some rewiring is occurring in the brain at sexual maturity. Conclusions This study shows that the brains of eels undergo major changes at the molecular level at sexual maturity that may include re-organization at the cellular level. Here, we have defined a set of genes that help to understand the molecular mechanisms controlling reproduction in eels. Some of these genes have previously described functions while many others have roles that have yet to be characterized in a reproductive context. Since most of the genes examined here have orthologs in other vertebrates, the results of this study will contribute to the body of knowledge concerning reproduction in vertebrates as well as to an improved understanding of eel biology. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-799) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Allison M Churcher
- CCMAR- Centre for Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
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Zagozewski JL, Zhang Q, Pinto VI, Wigle JT, Eisenstat DD. The role of homeobox genes in retinal development and disease. Dev Biol 2014; 393:195-208. [PMID: 25035933 DOI: 10.1016/j.ydbio.2014.07.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 07/02/2014] [Accepted: 07/08/2014] [Indexed: 11/18/2022]
Abstract
Homeobox genes are an evolutionarily conserved class of transcription factors that are critical for development of many organ systems, including the brain and eye. During retinogenesis, homeodomain-containing transcription factors, which are encoded by homeobox genes, play essential roles in the regionalization and patterning of the optic neuroepithelium, specification of retinal progenitors and differentiation of all seven of the retinal cell classes that derive from a common progenitor. Homeodomain transcription factors control retinal cell fate by regulating the expression of target genes required for retinal progenitor cell fate decisions and for terminal differentiation of specific retinal cell types. The essential role of homeobox genes during retinal development is demonstrated by the number of human eye diseases, including colobomas and anophthalmia, which are attributed to homeobox gene mutations. In the following review, we highlight the role of homeodomain transcription factors during retinogenesis and regulation of their gene targets. Understanding the complexities of vertebrate retina development will enhance our ability to drive differentiation of specific retinal cell types towards novel cell-based replacement therapies for retinal degenerative diseases.
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Affiliation(s)
- Jamie L Zagozewski
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada T6G 2H7
| | - Qi Zhang
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, MB, Canada R3E 0J9
| | - Vanessa I Pinto
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, Canada R3E 0J9
| | - Jeffrey T Wigle
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, Canada R3E 0J9; Institute of Cardiovascular Sciences, St. Boniface Hospital Research Institute, Winnipeg, MB, Canada R2H 2A6
| | - David D Eisenstat
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada T6G 2H7; Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, Canada R3E 0J9; Department of Pediatrics, University of Alberta, Edmonton, AB, Canada T6G 1C9.
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Bai L, Kiyama T, Li H, Wang SW. Birth of cone bipolar cells, but not rod bipolar cells, is associated with existing RGCs. PLoS One 2014; 9:e83686. [PMID: 24392091 PMCID: PMC3879276 DOI: 10.1371/journal.pone.0083686] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 11/14/2013] [Indexed: 12/12/2022] Open
Abstract
Retinal ganglion cells (RGCs) play important roles in retinogenesis. They are required for normal retinal histogenesis and retinal cell number balance. Developmental RGC loss is typically characterized by initial retinal neuronal number imbalance and subsequent loss of retinal neurons. However, it is not clear whether loss of a specific non-RGC cell type in the RGC-depleted retina is due to reduced cell production or subsequent degeneration. Taking advantage of three knockout mice with varying degrees of RGC depletion, we re-examined bipolar cell production in these retinas from various aspects. Results show that generation of the cone bipolar cells is correlated with the existing number of RGCs. However, generation of the rod bipolar cells is unaffected by RGC shortage. Results report the first observation that RGCs selectively influence the genesis of subsequent retinal cell types.
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Affiliation(s)
- Ling Bai
- Department of Ophthalmology, the Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, China
| | - Takae Kiyama
- Department of Ophthalmology and Visual Science, University of Texas Health Science Center at Houston Medical School, Houston, Texas, United States of America
| | - Hongyan Li
- Department of Ophthalmology and Visual Science, University of Texas Health Science Center at Houston Medical School, Houston, Texas, United States of America
| | - Steven W. Wang
- Department of Ophthalmology and Visual Science, University of Texas Health Science Center at Houston Medical School, Houston, Texas, United States of America
- * E-mail:
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41
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Cerdá-Esteban N, Spagnoli FM. Glimpse into Hox and tale regulation of cell differentiation and reprogramming. Dev Dyn 2013; 243:76-87. [PMID: 24123411 DOI: 10.1002/dvdy.24075] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 09/15/2013] [Accepted: 10/04/2013] [Indexed: 12/20/2022] Open
Abstract
During embryonic development, cells become gradually restricted in their developmental potential and start elaborating lineage-specific transcriptional networks to ultimately acquire a unique differentiated state. Hox genes play a central role in specifying regional identities, thereby providing the cell with critical information on positional value along its differentiation path. The exquisite DNA-binding specificity of the Hox proteins is frequently dependent upon their interaction with members of the TALE family of homeodomain proteins. In addition to their function as Hox-cofactors, TALE homeoproteins control multiple crucial developmental processes through Hox-independent mechanisms. Here, we will review recent findings on the function of both Hox and TALE proteins in cell differentiation, referring mostly to vertebrate species. In addition, we will discuss the direct implications of this knowledge on cell plasticity and cell reprogramming.
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Affiliation(s)
- Nuria Cerdá-Esteban
- Laboratory of Molecular and Cellular Basis of Embryonic Development, Max Delbrück Center for Molecular Medicine, Berlin, Germany
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Islet-1 immunoreactivity in the developing retina of Xenopus laevis. ScientificWorldJournal 2013; 2013:740420. [PMID: 24348185 PMCID: PMC3844241 DOI: 10.1155/2013/740420] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 09/22/2013] [Indexed: 01/09/2023] Open
Abstract
The LIM-homeodomain transcription factor Islet1 (Isl1) has been widely used as a marker of neuronal differentiation in the developing visual system of different classes of vertebrates, including mammals, birds, reptiles, and fish. In the present study, we analyzed the spatial and temporal distribution of Isl1-immunoreactive cells during Xenopus laevis retinal development and its relation to the formation of the retinal layers, and in combination with different markers of cell differentiation. The earliest Isl1 expression appeared at St29-30 in the cell nuclei of sparse differentiating neuroblasts located in the vitreal surface of the undifferentiated retina. At St35-36, abundant Isl1-positive cells accumulated at the vitreal surface of the neuroepithelium. As development proceeded and through the postmetamorphic juveniles, Isl1 expression was identified in subpopulations of ganglion cells and in subsets of amacrine, bipolar, and horizontal cells. These data together suggest a possible role for Isl1 in the early differentiation and maintenance of different retinal cell types, and Isl1 can serve as a specific molecular marker for the study of retinal cell specification in X. laevis.
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Star EN, Zhu M, Shi Z, Liu H, Pashmforoush M, Sauve Y, Bruneau BG, Chow RL. Regulation of retinal interneuron subtype identity by the Iroquois homeobox gene Irx6. Development 2013; 139:4644-55. [PMID: 23172916 DOI: 10.1242/dev.081729] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Interneuronal subtype diversity lies at the heart of the distinct molecular properties and synaptic connections that shape the formation of the neuronal circuits that are necessary for the complex spatial and temporal processing of sensory information. Here, we investigate the role of Irx6, a member of the Iroquois homeodomain transcription factor family, in regulating the development of retinal bipolar interneurons. Using a knock-in reporter approach, we show that, in the mouse retina, Irx6 is expressed in type 2 and 3a OFF bipolar interneurons and is required for the expression of cell type-specific markers in these cells, likely through direct transcriptional regulation. In Irx6 mutant mice, presumptive type 3a bipolar cells exhibit an expansion of their axonal projection domain to the entire OFF region of the inner plexiform layer, and adopt molecular features of both type 2 and 3a bipolar cells, highlighted by the ectopic upregulation of neurokinin 3 receptor (Nk3r) and Vsx1. These findings reveal Irx6 as a key regulator of type 3a bipolar cell identity that prevents these cells from adopting characteristic features of type 2 bipolar cells. Analysis of the Irx6;Vsx1 double null retina suggests that the terminal differentiation of type 2 bipolar cells is dependent on the combined expression of the transcription factors Irx6 and Vsx1, but also points to the existence of Irx6;Vsx1-independent mechanisms in regulating OFF bipolar subtype-specific gene expression. This work provides insight into the generation of neuronal subtypes by revealing a mechanism in which opposing, yet interdependent, transcription factors regulate subtype identity.
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Affiliation(s)
- Erin N Star
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada
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Xiang M. Intrinsic control of mammalian retinogenesis. Cell Mol Life Sci 2012; 70:2519-32. [PMID: 23064704 DOI: 10.1007/s00018-012-1183-2] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 09/25/2012] [Accepted: 09/27/2012] [Indexed: 01/18/2023]
Abstract
The generation of appropriate and diverse neuronal and glial types and subtypes during development constitutes the critical first step toward assembling functional neural circuits. During mammalian retinogenesis, all seven neuronal and glial cell types present in the adult retina are specified from multipotent progenitors by the combined action of various intrinsic and extrinsic factors. Tremendous progress has been made over the past two decades in uncovering the complex molecular mechanisms that control retinal cell diversification. Molecular genetic studies coupled with bioinformatic approaches have identified numerous transcription factors and cofactors as major intrinsic regulators leading to the establishment of progenitor multipotency and eventual differentiation of various retinal cell types and subtypes. More recently, non-coding RNAs have emerged as another class of intrinsic factors involved in generating retinal cell diversity. These intrinsic regulatory factors are found to act in different developmental processes to establish progenitor multipotency, define progenitor competence, determine cell fates, and/or specify cell types and subtypes.
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Affiliation(s)
- Mengqing Xiang
- Center for Advanced Biotechnology and Medicine, Rutgers University, 679 Hoes Lane West, Piscataway, NJ, 08854, USA.
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45
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Abstract
The original hedgehog (hh) gene was found in Drosophila and named for the appearance of a mutant phenotype which causes an embryo to be covered with pointy denticles, thus resembling a hedgehog. The hedgehog family consists of sonic hedgehog (Shh), desert hedgehog (Dhh), and Indian hedgehog (Ihh). Shh is found in vertebrates and the best studied ligand of the hedgehog signaling pathway (Gilbert, 2000). It plays an important role in regulating vertebrate organogenesis, such as in the growth of digits on limbs and organization of the brain, and earlier studies also show that it is important during retinal development (for a review, see Amato et al., 2004). Hedgehog expression drives waves of neurogenesis in animal retina, although genetic programs that control its expression are poorly elucidated. Recently, a novel transcriptional cascade which involves the atonal and Iroquois gene family was proposed in the regulation of hedgehog waves during vertebrate retinal development (Choy et al., 2010). This chapter will focus on Shh by addressing its signaling mechanisms and roles in vertebrate eye development, as well as a novel finding in retinogenesis.
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Kim KH, Rosen A, Bruneau BG, Hui CC, Backx PH. Iroquois homeodomain transcription factors in heart development and function. Circ Res 2012; 110:1513-24. [PMID: 22628575 DOI: 10.1161/circresaha.112.265041] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Numerous cardiac transcription factors play overlapping roles in both the specification and proliferation of the cardiac tissues and chambers during heart development. It has become increasingly apparent that cardiac transcription factors also play critical roles in the regulation of expression of many functional genes in the prenatal and postnatal hearts. Accordingly, mutations of cardiac transcription factors cannot only result in congenital heart defects but also alter heart function thereby predisposing to heart disease and cardiac arrhythmias. In this review, we summarize the roles of Iroquois homeobox (Irx) family of transcription factors in heart development and function. In all, 6 Irx genes are expressed with distinct and overlapping patterns in the mammalian heart. Studies in several animal models demonstrate that Irx genes are important for the establishment of ventricular chamber properties, the ventricular conduction system, as well as heterogeneity of the ventricular repolarization. The molecular mechanisms by which Irx proteins regulate gene expression and the clinical relevance of Irx functions in the heart are discussed.
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Affiliation(s)
- Kyoung-Han Kim
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
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Mutations in IRX5 impair craniofacial development and germ cell migration via SDF1. Nat Genet 2012; 44:709-13. [PMID: 22581230 DOI: 10.1038/ng.2259] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Accepted: 04/02/2012] [Indexed: 12/18/2022]
Abstract
Using homozygosity mapping and locus resequencing, we found that alterations in the homeodomain of the IRX5 transcription factor cause a recessive congenital disorder affecting face, brain, blood, heart, bone and gonad development. We found through in vivo modeling in Xenopus laevis embryos that Irx5 modulates the migration of progenitor cell populations in branchial arches and gonads by repressing Sdf1. We further found that transcriptional control by Irx5 is modulated by direct protein-protein interaction with two GATA zinc-finger proteins, GATA3 and TRPS1; disruptions of these proteins also cause craniofacial dysmorphisms. Our findings suggest that IRX proteins integrate combinatorial transcriptional inputs to regulate key signaling molecules involved in the ontogeny of multiple organs during embryogenesis and homeostasis.
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Zhang Y, Yang Y, Trujillo C, Zhong W, Leung YF. The expression of irx7 in the inner nuclear layer of zebrafish retina is essential for a proper retinal development and lamination. PLoS One 2012; 7:e36145. [PMID: 22540019 PMCID: PMC3335143 DOI: 10.1371/journal.pone.0036145] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Accepted: 03/26/2012] [Indexed: 01/24/2023] Open
Abstract
Irx7, a member in the zebrafish iroquois transcription factor (TF) family, has been shown to control brain patterning. During retinal development, irx7's expression was found to appear exclusively in the inner nuclear layer (INL) as soon as the prospective INL cells withdraw from the cell cycle and during retinal lamination. In Irx7-deficient retinas, the formation of a proper retinal lamination was disrupted and the differentiation of INL cell types, including amacrine, horizontal, bipolar and Muller cells, was compromised. Despite irx7's exclusive expression in the INL, photoreceptors differentiation was also compromised in Irx7-deficient retinas. Compared with other retinal cell types, ganglion cells differentiated relatively well in these retinas, except for their dendritic projections into the inner plexiform layer (IPL). In fact, the neuronal projections of amacrine and bipolar cells into the IPL were also diminished. These indicate that the retinal lamination issue in the Irx7-deficient retinas is likely caused by the attenuation of the neurite outgrowth. Since the expression of known TFs that can specify specific retinal cell type was also altered in Irx7-deficient retinas, thus the irx7 gene network is possibly a novel regulatory circuit for retinal development and lamination.
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Affiliation(s)
- Yuqing Zhang
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Yifan Yang
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Caleb Trujillo
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Wenxuan Zhong
- Department of Statistics, University of Illinois at Urbana-Champaign, Champaign, Illinois, United States of America
| | - Yuk Fai Leung
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine Lafayette, Indiana, United States of America
- * E-mail:
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Shi Z, Jervis D, Nickerson PEB, Chow RL. Requirement for the paired-like homeodomain transcription factor VSX1 in type 3a mouse retinal bipolar cell terminal differentiation. J Comp Neurol 2012; 520:117-29. [PMID: 21674500 DOI: 10.1002/cne.22697] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Retinal bipolar cells make up a class of at least 11 distinct interneurons that have been classified through morphological and molecular approaches. Previous work has shown that the paired-like homeodomain transcription factor Vsx1 is essential for the proper development of a subset of these interneurons. In Vsx1-null mice, bipolar cells are properly specified but exhibit terminal differentiation defects characterized by reduced expression of OFF bipolar cell markers and defects in OFF visual signaling. Here, we further examined the role of Vsx1 in OFF bipolar cells using recently identified cell-type-specific markers. In contrast to its previously characterized expression in type 2 OFF bipolar cells, Vsx1 expression was not detected in type 3 OFF bipolar cells, by either immunohistological or transgenic reporter labeling approaches. This observation was unexpected given previous findings that Cabp5 immunolabeling of type 3 bipolar cell axon terminals is reduced in Vsx1-null mice. However, we observed reduced levels of the type 3a bipolar cell marker hyperpolarization-activated and cyclic nucleotide-gated channel 4 (HCN4) in Vsx1-null mice, which is consistent with a requirement for Vsx1 in type 3 bipolar cell differentiation. In contrast, expression of the type 3b bipolar cell marker regulatory subunit RII-beta of protein kinase A was unchanged. Despite the absence of Vsx1 in mature type 3 bipolar cells, colabeling of Vsx1 and HCN4 was observed at postnatal stages. These findings reveal a role for Vsx1 in type 3a bipolar cells and suggest that Vsx1 function is required transiently in this cell type during the postnatal period.
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Affiliation(s)
- Zhiwei Shi
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
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A transcriptional program promotes remodeling of GABAergic synapses in Caenorhabditis elegans. J Neurosci 2011; 31:15362-75. [PMID: 22031882 DOI: 10.1523/jneurosci.3181-11.2011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although transcription factors are known to regulate synaptic plasticity, downstream genes that contribute to neural circuit remodeling are largely undefined. In Caenorhabditis elegans, GABAergic Dorsal D (DD) motor neuron synapses are relocated to new sites during larval development. This remodeling program is blocked in Ventral D (VD) GABAergic motor neurons by the COUP-TF (chicken ovalbumin upstream promoter transcription factor) homolog, UNC-55. We exploited this UNC-55 function to identify downstream synaptic remodeling genes that encode a diverse array of protein types including ion channels, cytoskeletal components, and transcription factors. We show that one of these targets, the Iroquois-like homeodomain protein, IRX-1, functions as a key regulator of remodeling in DD neurons. Our discovery of irx-1 as an unc-55-regulated target defines a transcriptional pathway that orchestrates an intricate synaptic remodeling program. Moreover, the well established roles of these conserved transcription factors in mammalian neural development suggest that a similar cascade may also control synaptic plasticity in more complex nervous systems.
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