1
|
Nishino R, Nomura-Komoike K, Iida T, Fujieda H. Cell cycle-dependent activation of proneural transcription factor expression and reactive gliosis in rat Müller glia. Sci Rep 2023; 13:22712. [PMID: 38123648 PMCID: PMC10733309 DOI: 10.1038/s41598-023-50222-0] [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: 10/02/2023] [Accepted: 12/16/2023] [Indexed: 12/23/2023] Open
Abstract
Retinal Müller glia have a capacity to regenerate neurons in lower vertebrates like zebrafish, but such ability is extremely limited in mammals. In zebrafish, Müller glia proliferate after injury, which promotes their neurogenic reprogramming while inhibiting reactive gliosis. In mammals, however, how the cell cycle affects the fate of Müller glia after injury remains unclear. Here, we focused on the expression of proneural transcription factors, Ngn2 and Ascl1, and a gliosis marker glial fibrillary acidic protein (GFAP) in rat Müller glia after N-methyl-N-nitrosourea (MNU)-induced photoreceptor injury and analyzed the role of Müller glia proliferation in the regulation of their expression using retinal explant cultures. Thymidine-induced G1/S arrest of Müller glia proliferation significantly hampered the expression of Ascl1, Ngn2, and GFAP, and release from the arrest induced their upregulation. The migration of Müller glia nuclei into the outer nuclear layer was also shown to be cell cycle-dependent. These data suggest that, unlike the situation in zebrafish, cell cycle progression of Müller glia in mammals promotes both neurogenic reprogramming and reactive gliosis, which may be one of the mechanisms underlying the limited regenerative capacity of the mammalian retina.
Collapse
Affiliation(s)
- Reiko Nishino
- Department of Anatomy and Neurobiology, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan
- Department of Ophthalmology, School of Medicine, Tokyo Women's Medical University, Tokyo, Japan
| | - Kaori Nomura-Komoike
- Department of Anatomy and Neurobiology, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan
| | - Tomohiro Iida
- Department of Ophthalmology, School of Medicine, Tokyo Women's Medical University, Tokyo, Japan
| | - Hiroki Fujieda
- Department of Anatomy and Neurobiology, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan.
| |
Collapse
|
2
|
Seifert AW, Duncan EM, Zayas RM. Enduring questions in regenerative biology and the search for answers. Commun Biol 2023; 6:1139. [PMID: 37945686 PMCID: PMC10636051 DOI: 10.1038/s42003-023-05505-7] [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: 06/09/2023] [Accepted: 10/25/2023] [Indexed: 11/12/2023] Open
Abstract
The potential for basic research to uncover the inner workings of regenerative processes and produce meaningful medical therapies has inspired scientists, clinicians, and patients for hundreds of years. Decades of studies using a handful of highly regenerative model organisms have significantly advanced our knowledge of key cell types and molecular pathways involved in regeneration. However, many questions remain about how regenerative processes unfold in regeneration-competent species, how they are curtailed in non-regenerative organisms, and how they might be induced (or restored) in humans. Recent technological advances in genomics, molecular biology, computer science, bioengineering, and stem cell research hold promise to collectively provide new experimental evidence for how different organisms accomplish the process of regeneration. In theory, this new evidence should inform the design of new clinical approaches for regenerative medicine. A deeper understanding of how tissues and organs regenerate will also undoubtedly impact many adjacent scientific fields. To best apply and adapt these new technologies in ways that break long-standing barriers and answer critical questions about regeneration, we must combine the deep knowledge of developmental and evolutionary biologists with the hard-earned expertise of scientists in mechanistic and technical fields. To this end, this perspective is based on conversations from a workshop we organized at the Banbury Center, during which a diverse cross-section of the regeneration research community and experts in various technologies discussed enduring questions in regenerative biology. Here, we share the questions this group identified as significant and unanswered, i.e., known unknowns. We also describe the obstacles limiting our progress in answering these questions and how expanding the number and diversity of organisms used in regeneration research is essential for deepening our understanding of regenerative capacity. Finally, we propose that investigating these problems collaboratively across a diverse network of researchers has the potential to advance our field and produce unexpected insights into important questions in related areas of biology and medicine.
Collapse
Affiliation(s)
- Ashley W Seifert
- Department of Biology, University of Kentucky, Lexington, KY, 40506, USA.
| | - Elizabeth M Duncan
- Department of Biology, University of Kentucky, Lexington, KY, 40506, USA.
| | - Ricardo M Zayas
- Department of Biology, San Diego State University, San Diego, CA, 92182, USA.
| |
Collapse
|
3
|
Zhang X, Leavey P, Appel H, Makrides N, Blackshaw S. Molecular mechanisms controlling vertebrate retinal patterning, neurogenesis, and cell fate specification. Trends Genet 2023; 39:736-757. [PMID: 37423870 PMCID: PMC10529299 DOI: 10.1016/j.tig.2023.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 07/11/2023]
Abstract
This review covers recent advances in understanding the molecular mechanisms controlling neurogenesis and specification of the developing retina, with a focus on insights obtained from comparative single cell multiomic analysis. We discuss recent advances in understanding the mechanisms by which extrinsic factors trigger transcriptional changes that spatially pattern the optic cup (OC) and control the initiation and progression of retinal neurogenesis. We also discuss progress in unraveling the core evolutionarily conserved gene regulatory networks (GRNs) that specify early- and late-state retinal progenitor cells (RPCs) and neurogenic progenitors and that control the final steps in determining cell identity. Finally, we discuss findings that provide insight into regulation of species-specific aspects of retinal patterning and neurogenesis, including consideration of key outstanding questions in the field.
Collapse
Affiliation(s)
- Xin Zhang
- Department of Ophthalmology, Columbia University School of Medicine, New York, NY, USA; Department of Pathology and Cell Biology, Columbia University School of Medicine, New York, NY, USA.
| | - Patrick Leavey
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Haley Appel
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Neoklis Makrides
- Department of Ophthalmology, Columbia University School of Medicine, New York, NY, USA
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Psychiatry and Behavioral Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
4
|
Agarwal D, Dash N, Mazo KW, Chopra M, Avila MP, Patel A, Wong RM, Jia C, Do H, Cheng J, Chiang C, Jurlina SL, Roshan M, Perry MW, Rho JM, Broyer R, Lee CD, Weinreb RN, Gavrilovici C, Oesch NW, Welsbie DS, Wahlin KJ. Human retinal ganglion cell neurons generated by synchronous BMP inhibition and transcription factor mediated reprogramming. NPJ Regen Med 2023; 8:55. [PMID: 37773257 PMCID: PMC10541876 DOI: 10.1038/s41536-023-00327-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 08/31/2023] [Indexed: 10/01/2023] Open
Abstract
In optic neuropathies, including glaucoma, retinal ganglion cells (RGCs) die. Cell transplantation and endogenous regeneration offer strategies for retinal repair, however, developmental programs required for this to succeed are incompletely understood. To address this, we explored cellular reprogramming with transcription factor (TF) regulators of RGC development which were integrated into human pluripotent stem cells (PSCs) as inducible gene cassettes. When the pioneer factor NEUROG2 was combined with RGC-expressed TFs (ATOH7, ISL1, and POU4F2) some conversion was observed and when pre-patterned by BMP inhibition, RGC-like induced neurons (RGC-iNs) were generated with high efficiency in just under a week. These exhibited transcriptional profiles that were reminiscent of RGCs and exhibited electrophysiological properties, including AMPA-mediated synaptic transmission. Additionally, we demonstrated that small molecule inhibitors of DLK/LZK and GCK-IV can block neuronal death in two pharmacological axon injury models. Combining developmental patterning with RGC-specific TFs thus provided valuable insight into strategies for cell replacement and neuroprotection.
Collapse
Affiliation(s)
- Devansh Agarwal
- Shu Chien-Gene Lay Department of Bioengineering, UC San Diego, La Jolla, CA, USA
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Nicholas Dash
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Kevin W Mazo
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Manan Chopra
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Maria P Avila
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Amit Patel
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Ryan M Wong
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Cairang Jia
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Hope Do
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Jie Cheng
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Colette Chiang
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Shawna L Jurlina
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Mona Roshan
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Michael W Perry
- Department of Biological Sciences, UC San Diego, La Jolla, CA, USA
| | - Jong M Rho
- Department of Neurosciences, UC San Diego, La Jolla, CA, USA
| | - Risa Broyer
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Cassidy D Lee
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Robert N Weinreb
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | | | - Nicholas W Oesch
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
- Department of Psychology, UC San Diego, La Jolla, CA, USA
| | - Derek S Welsbie
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA
| | - Karl J Wahlin
- Viterbi Family Department of Ophthalmology & the Shiley Eye Institute, UC San Diego, La Jolla, CA, USA.
| |
Collapse
|
5
|
Ge Y, Chen X, Nan N, Bard J, Wu F, Yergeau D, Liu T, Wang J, Mu X. Key transcription factors influence the epigenetic landscape to regulate retinal cell differentiation. Nucleic Acids Res 2023; 51:2151-2176. [PMID: 36715342 PMCID: PMC10018358 DOI: 10.1093/nar/gkad026] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 01/05/2023] [Accepted: 01/09/2023] [Indexed: 01/31/2023] Open
Abstract
How the diverse neural cell types emerge from multipotent neural progenitor cells during central nervous system development remains poorly understood. Recent scRNA-seq studies have delineated the developmental trajectories of individual neural cell types in many neural systems including the neural retina. Further understanding of the formation of neural cell diversity requires knowledge about how the epigenetic landscape shifts along individual cell lineages and how key transcription factors regulate these changes. In this study, we dissect the changes in the epigenetic landscape during early retinal cell differentiation by scATAC-seq and identify globally the enhancers, enriched motifs, and potential interacting transcription factors underlying the cell state/type specific gene expression in individual lineages. Using CUT&Tag, we further identify the enhancers bound directly by four key transcription factors, Otx2, Atoh7, Pou4f2 and Isl1, including those dependent on Atoh7, and uncover the sequential and combinatorial interactions of these factors with the epigenetic landscape to control gene expression along individual retinal cell lineages such as retinal ganglion cells (RGCs). Our results reveal a general paradigm in which transcription factors collaborate and compete to regulate the emergence of distinct retinal cell types such as RGCs from multipotent retinal progenitor cells (RPCs).
Collapse
Affiliation(s)
- Yichen Ge
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Xushen Chen
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Nan Nan
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
- Department of Biostatistics, School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, USA
| | - Jonathan Bard
- New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, USA
| | - Fuguo Wu
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Donald Yergeau
- New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, USA
| | - Tao Liu
- Department of Biostatistics & Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Jie Wang
- Department of Biostatistics & Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Xiuqian Mu
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| |
Collapse
|
6
|
Keeley PW, Patel PS, Ryu MS, Reese BE. Neurog2 regulates Isl1 to modulate horizontal cell number. Development 2023; 150:dev201315. [PMID: 36537573 PMCID: PMC10108602 DOI: 10.1242/dev.201315] [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: 09/22/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022]
Abstract
The population sizes of different retinal cell types vary between different strains of mice, and that variation can be mapped to genomic loci in order to identify its polygenic origin. In some cases, controlling genes act independently, whereas in other instances, they exhibit epistasis. Here, we identify an epistatic interaction revealed through the mapping of quantitative trait loci from a panel of recombinant inbred strains of mice. The population of retinal horizontal cells exhibits a twofold variation in number, mapping to quantitative trait loci on chromosomes 3 and 13, where these loci are shown to interact epistatically. We identify a prospective genetic interaction underlying this, mediated by the bHLH transcription factor Neurog2, at the chromosome 3 locus, functioning to repress the LIM homeodomain transcription factor Isl1, at the chromosome 13 locus. Using single and double conditional knockout mice, we confirm the countervailing actions of each gene, and validate in vitro a crucial role for two single nucleotide polymorphisms in the 5'UTR of Isl1, one of which yields a novel E-box, mediating the repressive action of Neurog2.
Collapse
Affiliation(s)
- Patrick W. Keeley
- Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-5060, USA
| | - Pooja S. Patel
- Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-5060, USA
| | - Matthew S. Ryu
- Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-5060, USA
| | - Benjamin E. Reese
- Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-5060, USA
- Department of Psychological and Brain Sciences, University of California at Santa Barbara, Santa Barbara, CA 93106-5060, USA
| |
Collapse
|
7
|
Sun C, Chen S. Disease-causing mutations in genes encoding transcription factors critical for photoreceptor development. Front Mol Neurosci 2023; 16:1134839. [PMID: 37181651 PMCID: PMC10172487 DOI: 10.3389/fnmol.2023.1134839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 04/04/2023] [Indexed: 05/16/2023] Open
Abstract
Photoreceptor development of the vertebrate visual system is controlled by a complex transcription regulatory network. OTX2 is expressed in the mitotic retinal progenitor cells (RPCs) and controls photoreceptor genesis. CRX that is activated by OTX2 is expressed in photoreceptor precursors after cell cycle exit. NEUROD1 is also present in photoreceptor precursors that are ready to specify into rod and cone photoreceptor subtypes. NRL is required for the rod fate and regulates downstream rod-specific genes including the orphan nuclear receptor NR2E3 which further activates rod-specific genes and simultaneously represses cone-specific genes. Cone subtype specification is also regulated by the interplay of several transcription factors such as THRB and RXRG. Mutations in these key transcription factors are responsible for ocular defects at birth such as microphthalmia and inherited photoreceptor diseases such as Leber congenital amaurosis (LCA), retinitis pigmentosa (RP) and allied dystrophies. In particular, many mutations are inherited in an autosomal dominant fashion, including the majority of missense mutations in CRX and NRL. In this review, we describe the spectrum of photoreceptor defects that are associated with mutations in the above-mentioned transcription factors, and summarize the current knowledge of molecular mechanisms underlying the pathogenic mutations. At last, we deliberate the outstanding gaps in our understanding of the genotype-phenotype correlations and outline avenues for future research of the treatment strategies.
Collapse
Affiliation(s)
- Chi Sun
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, MO, United States
- *Correspondence: Chi Sun,
| | - Shiming Chen
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, MO, United States
- Department of Developmental Biology, Washington University in St. Louis, St. Louis, MO, United States
| |
Collapse
|
8
|
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.
Collapse
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;,
| |
Collapse
|
9
|
Grigoryan EN. Self-Organization of the Retina during Eye Development, Retinal Regeneration In Vivo, and in Retinal 3D Organoids In Vitro. Biomedicines 2022; 10:1458. [PMID: 35740479 PMCID: PMC9221005 DOI: 10.3390/biomedicines10061458] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 06/16/2022] [Accepted: 06/18/2022] [Indexed: 11/23/2022] Open
Abstract
Self-organization is a process that ensures histogenesis of the eye retina. This highly intricate phenomenon is not sufficiently studied due to its biological complexity and genetic heterogeneity. The review aims to summarize the existing central theories and ideas for a better understanding of retinal self-organization, as well as to address various practical problems of retinal biomedicine. The phenomenon of self-organization is discussed in the spatiotemporal context and illustrated by key findings during vertebrate retina development in vivo and retinal regeneration in amphibians in situ. Described also are histotypic 3D structures obtained from the disaggregated retinal progenitor cells of birds and retinal 3D organoids derived from the mouse and human pluripotent stem cells. The review highlights integral parts of retinal development in these conditions. On the cellular level, these include competence, differentiation, proliferation, apoptosis, cooperative movements, and migration. On the physical level, the focus is on the mechanical properties of cell- and cell layer-derived forces and on the molecular level on factors responsible for gene regulation, such as transcription factors, signaling molecules, and epigenetic changes. Finally, the self-organization phenomenon is discussed as a basis for the production of retinal organoids, a promising model for a wide range of basic scientific and medical applications.
Collapse
Affiliation(s)
- Eleonora N Grigoryan
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 119334 Moscow, Russia
| |
Collapse
|
10
|
Zhang H, Zhuang P, Welchko RM, Dai M, Meng F, Turner DL. Regulation of retinal amacrine cell generation by miR-216b and Foxn3. Development 2022; 149:273765. [PMID: 34919141 PMCID: PMC8917416 DOI: 10.1242/dev.199484] [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: 01/31/2021] [Accepted: 12/07/2021] [Indexed: 01/19/2023]
Abstract
The mammalian retina contains a complex mixture of different types of neurons. We find that microRNA miR-216b is preferentially expressed in postmitotic retinal amacrine cells in the mouse retina, and expression of miR-216a/b and miR-217 in retina depend in part on Ptf1a, a transcription factor required for amacrine cell differentiation. Surprisingly, ectopic expression of miR-216b directed the formation of additional amacrine cells and reduced bipolar neurons in the developing retina. We identify the Foxn3 mRNA as a retinal target of miR-216b by Argonaute PAR-CLIP and reporter analysis. Inhibition of Foxn3, a transcription factor, in the postnatal developing retina by RNAi increased the formation of amacrine cells and reduced bipolar cell formation. Foxn3 disruption by CRISPR in embryonic retinal explants also increased amacrine cell formation, whereas Foxn3 overexpression inhibited amacrine cell formation prior to Ptf1a expression. Co-expression of Foxn3 partially reversed the effects of ectopic miR-216b on retinal cell formation. Our results identify Foxn3 as a novel regulator of interneuron formation in the developing retina and suggest that miR-216b likely regulates Foxn3 and other genes in amacrine cells.
Collapse
Affiliation(s)
- Huanqing Zhang
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Pei Zhuang
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Ryan M. Welchko
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Manhong Dai
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Fan Meng
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109-2200, USA,Department of Psychiatry, University of Michigan, Ann Arbor, MI 48109, USA
| | - David L. Turner
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109-2200, USA,Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA,Author for correspondence ()
| |
Collapse
|
11
|
Lyu P, Hoang T, Santiago CP, Thomas ED, Timms AE, Appel H, Gimmen M, Le N, Jiang L, Kim DW, Chen S, Espinoza DF, Telger AE, Weir K, Clark BS, Cherry TJ, Qian J, Blackshaw S. Gene regulatory networks controlling temporal patterning, neurogenesis, and cell-fate specification in mammalian retina. Cell Rep 2021; 37:109994. [PMID: 34788628 PMCID: PMC8642835 DOI: 10.1016/j.celrep.2021.109994] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 09/30/2021] [Accepted: 10/21/2021] [Indexed: 12/30/2022] Open
Abstract
Gene regulatory networks (GRNs), consisting of transcription factors and their target sites, control neurogenesis and cell-fate specification in the developing central nervous system. In this study, we use integrated single-cell RNA and single-cell ATAC sequencing (scATAC-seq) analysis in developing mouse and human retina to identify multiple interconnected, evolutionarily conserved GRNs composed of cell-type-specific transcription factors that both activate genes within their own network and inhibit genes in other networks. These GRNs control temporal patterning in primary progenitors, regulate transition from primary to neurogenic progenitors, and drive specification of each major retinal cell type. We confirm that NFI transcription factors selectively activate expression of genes promoting late-stage temporal identity in primary retinal progenitors and identify other transcription factors that regulate rod photoreceptor specification in postnatal retina. This study inventories cis- and trans-acting factors that control retinal development and can guide cell-based therapies aimed at replacing retinal neurons lost to disease.
Collapse
Affiliation(s)
- Pin Lyu
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Thanh Hoang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Clayton P Santiago
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Eric D Thomas
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Andrew E Timms
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Haley Appel
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Megan Gimmen
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Nguyet Le
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Lizhi Jiang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Dong Won Kim
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Siqi Chen
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - David F Espinoza
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ariel E Telger
- Department of Ophthalmology and Visual Sciences, Brotman Baty Institute, Seattle, WA 98195, USA
| | - Kurt Weir
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Brian S Clark
- Department of Ophthalmology and Visual Sciences, Brotman Baty Institute, Seattle, WA 98195, USA; Brotman Baty Institute, Seattle, WA 98195, USA; Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Timothy J Cherry
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA 98101, USA; Brotman Baty Institute, Seattle, WA 98195, USA; Department of Pediatrics, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Jiang Qian
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Seth Blackshaw
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| |
Collapse
|
12
|
Shiau F, Ruzycki PA, Clark BS. A single-cell guide to retinal development: Cell fate decisions of multipotent retinal progenitors in scRNA-seq. Dev Biol 2021; 478:41-58. [PMID: 34146533 PMCID: PMC8386138 DOI: 10.1016/j.ydbio.2021.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 06/07/2021] [Accepted: 06/08/2021] [Indexed: 12/20/2022]
Abstract
Recent advances in high throughput single-cell RNA sequencing (scRNA-seq) technology have enabled the simultaneous transcriptomic profiling of thousands of individual cells in a single experiment. To investigate the intrinsic process of retinal development, researchers have leveraged this technology to quantify gene expression in retinal cells across development, in multiple species, and from numerous important models of human disease. In this review, we summarize recent applications of scRNA-seq and discuss how these datasets have complemented and advanced our understanding of retinal progenitor cell competence, cell fate specification, and differentiation. Finally, we also highlight the outstanding questions in the field that advances in single-cell data generation and analysis will soon be able to answer.
Collapse
Affiliation(s)
- Fion Shiau
- John F Hardesty, MD Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Philip A Ruzycki
- John F Hardesty, MD Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Brian S Clark
- John F Hardesty, MD Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA; Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA.
| |
Collapse
|
13
|
Kaufman ML, Goodson NB, Park KU, Schwanke M, Office E, Schneider SR, Abraham J, Hensley A, Jones KL, Brzezinski JA. Initiation of Otx2 expression in the developing mouse retina requires a unique enhancer and either Ascl1 or Neurog2 activity. Development 2021; 148:dev199399. [PMID: 34143204 PMCID: PMC8254865 DOI: 10.1242/dev.199399] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 05/10/2021] [Indexed: 11/20/2022]
Abstract
During retinal development, a large subset of progenitors upregulates the transcription factor Otx2, which is required for photoreceptor and bipolar cell formation. How these retinal progenitor cells initially activate Otx2 expression is unclear. To address this, we investigated the cis-regulatory network that controls Otx2 expression in mice. We identified a minimal enhancer element, DHS-4D, that drove expression in newly formed OTX2+ cells. CRISPR/Cas9-mediated deletion of DHS-4D reduced OTX2 expression, but this effect was diminished in postnatal development. Systematic mutagenesis of the enhancer revealed that three basic helix-loop-helix (bHLH) transcription factor-binding sites were required for its activity. Single cell RNA-sequencing of nascent Otx2+ cells identified the bHLH factors Ascl1 and Neurog2 as candidate regulators. CRISPR/Cas9 targeting of these factors showed that only the simultaneous loss of Ascl1 and Neurog2 prevented OTX2 expression. Our findings suggest that Ascl1 and Neurog2 act either redundantly or in a compensatory fashion to activate the DHS-4D enhancer and Otx2 expression. We observed redundancy or compensation at both the transcriptional and enhancer utilization levels, suggesting that the mechanisms governing Otx2 regulation in the retina are flexible and robust.
Collapse
Affiliation(s)
- Michael L. Kaufman
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Noah B. Goodson
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ko Uoon Park
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Michael Schwanke
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Emma Office
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Sophia R. Schneider
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Joy Abraham
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Austin Hensley
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Kenneth L. Jones
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Joseph A. Brzezinski
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| |
Collapse
|
14
|
Zhang X, Mandric I, Nguyen KH, Nguyen TTT, Pellegrini M, Grove JCR, Barnes S, Yang XJ. Single Cell Transcriptomic Analyses Reveal the Impact of bHLH Factors on Human Retinal Organoid Development. Front Cell Dev Biol 2021; 9:653305. [PMID: 34055784 PMCID: PMC8155690 DOI: 10.3389/fcell.2021.653305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 03/22/2021] [Indexed: 11/13/2022] Open
Abstract
The developing retina expresses multiple bHLH transcription factors. Their precise functions and interactions in uncommitted retinal progenitors remain to be fully elucidated. Here, we investigate the roles of bHLH factors ATOH7 and Neurog2 in human ES cell-derived retinal organoids. Single cell transcriptome analyses identify three states of proliferating retinal progenitors: pre-neurogenic, neurogenic, and cell cycle-exiting progenitors. Each shows different expression profile of bHLH factors. The cell cycle-exiting progenitors feed into a postmitotic heterozygous neuroblast pool that gives rise to early born neuronal lineages. Elevating ATOH7 or Neurog2 expression accelerates the transition from the pre-neurogenic to the neurogenic state, and expands the exiting progenitor and neuroblast populations. In addition, ATOH7 and Neurog2 significantly, yet differentially, enhance retinal ganglion cell and cone photoreceptor production. Moreover, single cell transcriptome analyses reveal that ATOH7 and Neurog2 each assert positive autoregulation, and both suppress key bHLH factors associated with the pre-neurogenic and states and elevate bHLH factors expressed by exiting progenitors and differentiating neuroblasts. This study thus provides novel insight regarding how ATOH7 and Neurog2 impact human retinal progenitor behaviors and neuroblast fate choices.
Collapse
Affiliation(s)
- Xiangmei Zhang
- Department of Ophthalmology, Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Igor Mandric
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Kevin H Nguyen
- Department of Ophthalmology, Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Thao T T Nguyen
- Department of Ophthalmology, Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Matteo Pellegrini
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA, United States
| | - James C R Grove
- Department of Ophthalmology, Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Steven Barnes
- Department of Ophthalmology, Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States.,Doheny Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Xian-Jie Yang
- Department of Ophthalmology, Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States
| |
Collapse
|
15
|
Wu F, Bard JE, Kann J, Yergeau D, Sapkota D, Ge Y, Hu Z, Wang J, Liu T, Mu X. Single cell transcriptomics reveals lineage trajectory of retinal ganglion cells in wild-type and Atoh7-null retinas. Nat Commun 2021; 12:1465. [PMID: 33674582 PMCID: PMC7935890 DOI: 10.1038/s41467-021-21704-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 02/09/2021] [Indexed: 01/31/2023] Open
Abstract
Atoh7 has been believed to be essential for establishing the retinal ganglion cell (RGC) lineage, and Pou4f2 and Isl1 are known to regulate RGC specification and differentiation. Here we report our further study of the roles of these transcription factors. Using bulk RNA-seq, we identify genes regulated by the three transcription factors, which expand our understanding of the scope of downstream events. Using scRNA-seq on wild-type and mutant retinal cells, we reveal a transitional cell state of retinal progenitor cells (RPCs) co-marked by Atoh7 and other genes for different lineages and shared by all early retinal lineages. We further discover the unexpected emergence of the RGC lineage in the absence of Atoh7. We conclude that competence of RPCs for different retinal fates is defined by lineage-specific genes co-expressed in the transitional state and that Atoh7 defines the RGC competence and collaborates with other factors to shepherd transitional RPCs to the RGC lineage.
Collapse
Affiliation(s)
- Fuguo Wu
- Department of Ophthalmology/Ross Eye Institute, University at Buffalo, Buffalo, NY, USA
- New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, USA
| | - Jonathan E Bard
- New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, USA
| | - Julien Kann
- New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, USA
| | - Donald Yergeau
- New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, USA
| | - Darshan Sapkota
- Department of Ophthalmology/Ross Eye Institute, University at Buffalo, Buffalo, NY, USA
- New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, USA
| | - Yichen Ge
- Department of Ophthalmology/Ross Eye Institute, University at Buffalo, Buffalo, NY, USA
- New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, USA
| | - Zihua Hu
- New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, USA
| | - Jie Wang
- Department of Biostatistics & Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Tao Liu
- Department of Biostatistics & Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Xiuqian Mu
- Department of Ophthalmology/Ross Eye Institute, University at Buffalo, Buffalo, NY, USA.
- New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY, USA.
| |
Collapse
|
16
|
Oproescu AM, Han S, Schuurmans C. New Insights Into the Intricacies of Proneural Gene Regulation in the Embryonic and Adult Cerebral Cortex. Front Mol Neurosci 2021; 14:642016. [PMID: 33658912 PMCID: PMC7917194 DOI: 10.3389/fnmol.2021.642016] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 01/26/2021] [Indexed: 12/21/2022] Open
Abstract
Historically, the mammalian brain was thought to lack stem cells as no new neurons were found to be made in adulthood. That dogma changed ∼25 years ago with the identification of neural stem cells (NSCs) in the adult rodent forebrain. However, unlike rapidly self-renewing mature tissues (e.g., blood, intestinal crypts, skin), the majority of adult NSCs are quiescent, and those that become 'activated' are restricted to a few neurogenic zones that repopulate specific brain regions. Conversely, embryonic NSCs are actively proliferating and neurogenic. Investigations into the molecular control of the quiescence-to-proliferation-to-differentiation continuum in the embryonic and adult brain have identified proneural genes encoding basic-helix-loop-helix (bHLH) transcription factors (TFs) as critical regulators. These bHLH TFs initiate genetic programs that remove NSCs from quiescence and drive daughter neural progenitor cells (NPCs) to differentiate into specific neural cell subtypes, thereby contributing to the enormous cellular diversity of the adult brain. However, new insights have revealed that proneural gene activities are context-dependent and tightly regulated. Here we review how proneural bHLH TFs are regulated, with a focus on the murine cerebral cortex, drawing parallels where appropriate to other organisms and neural tissues. We discuss upstream regulatory events, post-translational modifications (phosphorylation, ubiquitinylation), protein-protein interactions, epigenetic and metabolic mechanisms that govern bHLH TF expression, stability, localization, and consequent transactivation of downstream target genes. These tight regulatory controls help to explain paradoxical findings of changes to bHLH activity in different cellular contexts.
Collapse
Affiliation(s)
- Ana-Maria Oproescu
- Sunnybrook Research Institute, Biological Sciences Platform, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Sisu Han
- Sunnybrook Research Institute, Biological Sciences Platform, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Carol Schuurmans
- Sunnybrook Research Institute, Biological Sciences Platform, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
17
|
Aslanpour S, Rosin JM, Balakrishnan A, Klenin N, Blot F, Gradwohl G, Schuurmans C, Kurrasch DM. Ascl1 is required to specify a subset of ventromedial hypothalamic neurons. Development 2020; 147:dev180067. [PMID: 32253239 DOI: 10.1242/dev.180067] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 03/23/2020] [Indexed: 03/01/2024]
Abstract
Despite clear physiological roles, the ventromedial hypothalamus (VMH) developmental programs are poorly understood. Here, we asked whether the proneural gene achaete-scute homolog 1 (Ascl1) contributes to VMH development. Ascl1 transcripts were detected in embryonic day (E) 10.5 to postnatal day 0 VMH neural progenitors. The elimination of Ascl1 reduced the number of VMH neurons at E12.5 and E15.5, particularly within the VMH-central (VMHC) and -dorsomedial (VMHDM) subdomains, and resulted in a VMH cell fate change from glutamatergic to GABAergic. We observed a loss of Neurog3 expression in Ascl1-/- hypothalamic progenitors and an upregulation of Neurog3 when Ascl1 was overexpressed. We also demonstrated a glutamatergic to GABAergic fate switch in Neurog3-null mutant mice, suggesting that Ascl1 might act via Neurog3 to drive VMH cell fate decisions. We also showed a concomitant increase in expression of the central GABAergic fate determinant Dlx1/2 in the Ascl1-null hypothalamus. However, Ascl1 was not sufficient to induce an ectopic VMH fate when overexpressed outside the normal window of competency. Combined, Ascl1 is required but not sufficient to specify the neurotransmitter identity of VMH neurons, acting in a transcriptional cascade with Neurog3.
Collapse
Affiliation(s)
- Shaghayegh Aslanpour
- Department of Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Jessica M Rosin
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Anjali Balakrishnan
- Sunnybrook Research Institute, Department of Biochemistry, University of Toronto, ON M4N 3M5, Canada
| | - Natalia Klenin
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Florence Blot
- Department of Development and Stem Cells, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM, Universite de Strasbourg, Illkirch 67400, France
| | - Gerard Gradwohl
- Department of Development and Stem Cells, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM, Universite de Strasbourg, Illkirch 67400, France
| | - Carol Schuurmans
- Sunnybrook Research Institute, Department of Biochemistry, University of Toronto, ON M4N 3M5, Canada
| | - Deborah M Kurrasch
- Department of Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| |
Collapse
|
18
|
Neurog2 Acts as a Classical Proneural Gene in the Ventromedial Hypothalamus and Is Required for the Early Phase of Neurogenesis. J Neurosci 2020; 40:3549-3563. [PMID: 32273485 DOI: 10.1523/jneurosci.2610-19.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 03/21/2020] [Accepted: 03/24/2020] [Indexed: 12/28/2022] Open
Abstract
The tuberal hypothalamus is comprised of the dorsomedial, ventromedial, and arcuate nuclei, as well as parts of the lateral hypothalamic area, and it governs a wide range of physiologies. During neurogenesis, tuberal hypothalamic neurons are thought to be born in a dorsal-to-ventral and outside-in pattern, although the accuracy of this description has been questioned over the years. Moreover, the intrinsic factors that control the timing of neurogenesis in this region are poorly characterized. Proneural genes, including Achate-scute-like 1 (Ascl1) and Neurogenin 3 (Neurog3) are widely expressed in hypothalamic progenitors and contribute to lineage commitment and subtype-specific neuronal identifies, but the potential role of Neurogenin 2 (Neurog2) remains unexplored. Birthdating in male and female mice showed that tuberal hypothalamic neurogenesis begins as early as E9.5 in the lateral hypothalamic and arcuate and rapidly expands to dorsomedial and ventromedial neurons by E10.5, peaking throughout the region by E11.5. We confirmed an outside-in trend, except for neurons born at E9.5, and uncovered a rostrocaudal progression but did not confirm a dorsal-ventral patterning to tuberal hypothalamic neuronal birth. In the absence of Neurog2, neurogenesis stalls, with a significant reduction in early-born BrdU+ cells but no change at later time points. Further, the loss of Ascl1 yielded a similar delay in neuronal birth, suggesting that Ascl1 cannot rescue the loss of Neurog2 and that these proneural genes act independently in the tuberal hypothalamus. Together, our findings show that Neurog2 functions as a classical proneural gene to regulate the temporal progression of tuberal hypothalamic neurogenesis.SIGNIFICANCE STATEMENT Here, we investigated the general timing and pattern of neurogenesis within the tuberal hypothalamus. Our results confirmed an outside-in trend of neurogenesis and uncovered a rostrocaudal progression. We also showed that Neurog2 acts as a classical proneural gene and is responsible for regulating the birth of early-born neurons within the ventromedial hypothalamus, acting independently of Ascl1 In addition, we revealed a role for Neurog2 in cell fate specification and differentiation of ventromedial -specific neurons. Last, Neurog2 does not have cross-inhibitory effects on Neurog1, Neurog3, and Ascl1 These findings are the first to reveal a role for Neurog2 in hypothalamic development.
Collapse
|
19
|
Patoori S, Jean-Charles N, Gopal A, Sulaiman S, Gopal S, Wang B, Souferi B, Emerson MM. Cis-regulatory analysis of Onecut1 expression in fate-restricted retinal progenitor cells. Neural Dev 2020; 15:5. [PMID: 32192535 PMCID: PMC7082998 DOI: 10.1186/s13064-020-00142-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 02/27/2020] [Indexed: 01/03/2023] Open
Abstract
Background The vertebrate retina consists of six major classes of neuronal cells. During development, these cells are generated from a pool of multipotent retinal progenitor cells (RPCs) that express the gene Vsx2. Fate-restricted RPCs have recently been identified, with limited mitotic potential and cell fate possibilities compared to multipotent RPCs. One population of fate-restricted RPCs, marked by activity of the regulatory element ThrbCRM1, gives rise to both cone photoreceptors and horizontal cells. These cells do not express Vsx2, but co-express the transcription factors (TFs) Onecut1 and Otx2, which bind to ThrbCRM1. The components of the gene regulatory networks that control the transition from multipotent to fate-restricted gene expression are not known. This work aims to identify and evaluate cis-regulatory elements proximal to Onecut1 to identify the gene regulatory networks involved in RPC fate-restriction. Method We identified regulatory elements through ATAC-seq and conservation, followed by reporter assays to screen for activity based on temporal and spatial criteria. The regulatory elements of interest were subject to deletion and mutation analysis to identify functional sequences and evaluated by quantitative flow cytometry assays. Finally, we combined the enhancer::reporter assays with candidate TF overexpression to evaluate the relationship between the TFs, the enhancers, and early vertebrate retinal development. Statistical tests included ANOVA, Kruskal-Wallis, or unpaired t-tests. Results Two regulatory elements, ECR9 and ECR65, were identified to be active in ThrbCRM1(+) restricted RPCs. Candidate bHLH binding sites were identified as critical sequences in both elements. Overexpression of candidate bHLH TFs revealed specific enhancer-bHLH interactions. Nhlh1 overexpression expanded ECR65 activity into the Vsx2(+) RPC population, and overexpression of NeuroD1/NeuroG2/NeuroD4 had a similar effect on ECR9. Furthermore, bHLHs that were able to activate ectopic ECR9 reporter were able to induce endogenous Otx2 expression. Conclusions This work reports a large-scale screen to identify spatiotemporally specific regulatory elements near the Onecut1 locus. These elements were used to identify distinct populations in the developing retina. In addition, fate-restricted regulatory elements responded differentially to bHLH factors, and suggest a role for retinal bHLHs upstream of the Otx2 and Onecut1 genes during the formation of restricted RPCs from multipotent RPCs.
Collapse
Affiliation(s)
- Sruti Patoori
- Biology PhD Program, The Graduate Center, The City University of New York, New York, NY, 10016, USA.,Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA
| | - Nathalie Jean-Charles
- Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA
| | - Ariana Gopal
- Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA
| | - Sacha Sulaiman
- Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA
| | - Sneha Gopal
- Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA.,Present Address: Doctoral program in Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Brian Wang
- Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA
| | - Benjamin Souferi
- Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA.,Present Address: Touro College of Osteopathic Medicine, New York, NY, 10027, USA
| | - Mark M Emerson
- Biology PhD Program, The Graduate Center, The City University of New York, New York, NY, 10016, USA. .,Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA. .,Biochemistry PhD Program, Graduate Center, City University of New York, New York, NY, 10016, USA.
| |
Collapse
|
20
|
Murphy DP, Hughes AEO, Lawrence KA, Myers CA, Corbo JC. Cis-regulatory basis of sister cell type divergence in the vertebrate retina. eLife 2019; 8:e48216. [PMID: 31633482 PMCID: PMC6802965 DOI: 10.7554/elife.48216] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 09/19/2019] [Indexed: 12/27/2022] Open
Abstract
Multicellular organisms evolved via repeated functional divergence of transcriptionally related sister cell types, but the mechanisms underlying sister cell type divergence are not well understood. Here, we study a canonical pair of sister cell types, retinal photoreceptors and bipolar cells, to identify the key cis-regulatory features that distinguish them. By comparing open chromatin maps and transcriptomic profiles, we found that while photoreceptor and bipolar cells have divergent transcriptomes, they share remarkably similar cis-regulatory grammars, marked by enrichment of K50 homeodomain binding sites. However, cell class-specific enhancers are distinguished by enrichment of E-box motifs in bipolar cells, and Q50 homeodomain motifs in photoreceptors. We show that converting K50 motifs to Q50 motifs represses reporter expression in bipolar cells, while photoreceptor expression is maintained. These findings suggest that partitioning of Q50 motifs within cell type-specific cis-regulatory elements was a critical step in the evolutionary divergence of the bipolar transcriptome from that of photoreceptors.
Collapse
Affiliation(s)
- Daniel P Murphy
- Department of Pathology and ImmunologyWashington University School of MedicineSt. LouisUnited States
| | - Andrew EO Hughes
- Department of Pathology and ImmunologyWashington University School of MedicineSt. LouisUnited States
| | - Karen A Lawrence
- Department of Pathology and ImmunologyWashington University School of MedicineSt. LouisUnited States
| | - Connie A Myers
- Department of Pathology and ImmunologyWashington University School of MedicineSt. LouisUnited States
| | - Joseph C Corbo
- Department of Pathology and ImmunologyWashington University School of MedicineSt. LouisUnited States
| |
Collapse
|
21
|
Taylor SM, Giuffre E, Moseley P, Hitchcock PF. The MicroRNA, miR-18a, Regulates NeuroD and Photoreceptor Differentiation in the Retina of Zebrafish. Dev Neurobiol 2019; 79:202-219. [PMID: 30615274 PMCID: PMC6351175 DOI: 10.1002/dneu.22666] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 12/13/2018] [Accepted: 12/14/2018] [Indexed: 12/21/2022]
Abstract
During embryonic retinal development, six types of retinal neurons are generated from multipotent progenitors in a strict spatiotemporal pattern. This pattern requires cell cycle exit (i.e. neurogenesis) and differentiation to be precisely regulated in a lineage‐specific manner. In zebrafish, the bHLH transcription factor NeuroD governs photoreceptor genesis through Notch signaling but also governs photoreceptor differentiation though distinct mechanisms that are currently unknown. Also unknown are the mechanisms that regulate NeuroD and the spatiotemporal pattern of photoreceptor development. Members of the miR‐17‐92 microRNA cluster regulate CNS neurogenesis, and a member of this cluster, miR‐18a, is predicted to target neuroD mRNA. The purpose of this study was to determine if, in the developing zebrafish retina, miR‐18a regulates NeuroD and if it plays a role in photoreceptor development. Quantitative RT‐PCR showed that, of the three miR‐18 family members (miR‐18a, b, and c), miR‐18a expression most closely parallels neuroD expression. Morpholino oligonucleotides and CRISPR/Cas9 gene editing were used for miR‐18a loss‐of‐function (LOF) and both resulted in larvae with more mature photoreceptors at 70 hpf without affecting cell proliferation. Western blot showed that miR‐18a LOF increases NeuroD protein levels and in vitro dual luciferase assay showed that miR‐18a directly interacts with the 3′ UTR of neuroD. Finally, tgif1 mutants have increased miR‐18a expression, less NeuroD protein and fewer mature photoreceptors, and the photoreceptor deficiency is rescued by miR‐18a knockdown. Together, these results show that, independent of neurogenesis, miR‐18a regulates the timing of photoreceptor differentiation and indicate that this occurs through post‐transcriptional regulation of NeuroD.
Collapse
Affiliation(s)
- Scott M Taylor
- Department of Biology, University of West Florida, 11000 University Parkway, Pensacola, Florida, 32514
| | - Emily Giuffre
- Department of Biology, University of West Florida, 11000 University Parkway, Pensacola, Florida, 32514
| | - Patience Moseley
- Department of Biology, University of West Florida, 11000 University Parkway, Pensacola, Florida, 32514
| | - Peter F Hitchcock
- Ophthalmology and Visual Sciences, University of Michigan, W. K. Kellogg Eye Center, 1000 Wall Street, Ann Arbor, Michigan, 48105
| |
Collapse
|
22
|
Kowalchuk AM, Maurer KA, Shoja-Taheri F, Brown NL. Requirements for Neurogenin2 during mouse postnatal retinal neurogenesis. Dev Biol 2018; 442:220-235. [PMID: 30048641 PMCID: PMC6143394 DOI: 10.1016/j.ydbio.2018.07.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 07/22/2018] [Accepted: 07/23/2018] [Indexed: 02/02/2023]
Abstract
During embryonic retinal development, the bHLH factor Neurog2 regulates the temporal progression of neurogenesis, but no role has been assigned for this gene in the postnatal retina. Using Neurog2 conditional mutants, we found that Neurog2 is necessary for the development of an early, embryonic cohort of rod photoreceptors, but also required by both a subset of cone bipolar subtypes, and rod bipolars. Using transcriptomics, we identified a subset of downregulated genes in P2 Neurog2 mutants, which act during rod differentiation, outer segment morphogenesis or visual processing. We also uncovered defects in neuronal cell culling, which suggests that the rod and bipolar cell phenotypes may arise via more complex mechanisms rather than a simple cell fate shift. However, given an overall phenotypic resemblance between Neurog2 and Blimp1 mutants, we explored the relationship between these two factors. We found that Blimp1 is downregulated between E12-birth in Neurog2 mutants, which probably reflects a dependence on Neurog2 in embryonic progenitor cells. Overall, we conclude that the Neurog2 gene is expressed and active prior to birth, but also exerts an influence on postnatal retinal neuron differentiation.
Collapse
Affiliation(s)
- Angelica M Kowalchuk
- Department of Cell Biology and Human Anatomy, University of California-Davis, Davis, CA 95616, USA
| | - Kate A Maurer
- Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA
| | - Farnaz Shoja-Taheri
- Department of Cell Biology and Human Anatomy, University of California-Davis, Davis, CA 95616, USA
| | - Nadean L Brown
- Department of Cell Biology and Human Anatomy, University of California-Davis, Davis, CA 95616, USA; Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA.
| |
Collapse
|
23
|
Ando M, Goto M, Hojo M, Kita A, Kitagawa M, Ohtsuka T, Kageyama R, Miyamoto S. The proneural bHLH genes Mash1, Math3 and NeuroD are required for pituitary development. J Mol Endocrinol 2018; 61:127-138. [PMID: 30307165 DOI: 10.1530/jme-18-0090] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Multiple signaling molecules and transcription factors are required for pituitary development. Activator-type bHLH genes Mash1, Math, NeuroD (Neurod) and Neurogenin (Neurog) are well known as key molecules in neural development. Although analyses of targeted mouse mutants have demonstrated involvement of these bHLH genes in pituitary development, studies with single-mutant mice could not elucidate their exact functions, because they cooperatively function and compensate each other. The aim of this study was to elucidate the roles of Mash1, Math3 and NeuroD in pituitary development. Mash1;Math3;NeuroD triple-mutant mice were analyzed by immunohistochemistry and quantitative real-time RT-PCR. Misexpression studies with retroviruses in pituisphere cultures were also performed. The triple-mutant adenohypophysis was morphologically normal, though the lumen of the neurohypophysis remained unclosed. However, in triple-mutant pituitaries, somatotropes, gonadotropes and corticotropes were severely decreased, whereas lactotropes were increased. Misexpression of Mash1 alone with retrovirus could not induce generation of hormonal cells, though Mash1 was involved in differentiation of pituitary progenitor cells. These data suggest that Mash1, Math3 and NeuroD cooperatively control the timing of pituitary progenitor cell differentiation and that they are also required for subtype specification of pituitary hormonal cells. Mash1 is necessary for corticotroph and gonadotroph differentiation, and compensated by Math3 and NeuroD. Math3 is necessary for somatotroph differentiation, and compensated by Mash1 and NeuroD. Neurog2 may compensate Mash1, Math3 and NeuroD during pituitary development. Furthermore, Mash1, Math3 and NeuroD are required for neurohypophysis development. Thus, Mash1, Math3 and NeuroD are required for pituitary development, and compensate each other.
Collapse
Affiliation(s)
- Mitsushige Ando
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Masanori Goto
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Masato Hojo
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Neurosurgery, Shiga Medical Center for Adults, Shiga, Japan
| | - Aya Kita
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Masashi Kitagawa
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Toshiyuki Ohtsuka
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Ryoichiro Kageyama
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Susumu Miyamoto
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan
| |
Collapse
|
24
|
Dennis DJ, Han S, Schuurmans C. bHLH transcription factors in neural development, disease, and reprogramming. Brain Res 2018; 1705:48-65. [PMID: 29544733 DOI: 10.1016/j.brainres.2018.03.013] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/07/2018] [Accepted: 03/10/2018] [Indexed: 01/16/2023]
Abstract
The formation of functional neural circuits in the vertebrate central nervous system (CNS) requires that appropriate numbers of the correct types of neuronal and glial cells are generated in their proper places and times during development. In the embryonic CNS, multipotent progenitor cells first acquire regional identities, and then undergo precisely choreographed temporal identity transitions (i.e. time-dependent changes in their identity) that determine how many neuronal and glial cells of each type they will generate. Transcription factors of the basic-helix-loop-helix (bHLH) family have emerged as key determinants of neural cell fate specification and differentiation, ensuring that appropriate numbers of specific neuronal and glial cell types are produced. Recent studies have further revealed that the functions of these bHLH factors are strictly regulated. Given their essential developmental roles, it is not surprising that bHLH mutations and de-regulated expression are associated with various neurological diseases and cancers. Moreover, the powerful ability of bHLH factors to direct neuronal and glial cell fate specification and differentiation has been exploited in the relatively new field of cellular reprogramming, in which pluripotent stem cells or somatic stem cells are converted to neural lineages, often with a transcription factor-based lineage conversion strategy that includes one or more of the bHLH genes. These concepts are reviewed herein.
Collapse
Affiliation(s)
- Daniel J Dennis
- Sunnybrook Research Institute, 2075 Bayview Ave, Toronto, ON M4N3M5, Canada
| | - Sisu Han
- Sunnybrook Research Institute, 2075 Bayview Ave, Toronto, ON M4N3M5, Canada; Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Carol Schuurmans
- Sunnybrook Research Institute, 2075 Bayview Ave, Toronto, ON M4N3M5, Canada; Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
| |
Collapse
|
25
|
Chouchane M, Costa MR. Instructing neuronal identity during CNS development and astroglial-lineage reprogramming: Roles of NEUROG2 and ASCL1. Brain Res 2018; 1705:66-74. [PMID: 29510143 DOI: 10.1016/j.brainres.2018.02.045] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 02/16/2018] [Accepted: 02/27/2018] [Indexed: 01/02/2023]
Abstract
The adult mammalian brain contains an enormous variety of neuronal types, which are generally categorized in large groups, based on their neurochemical identity, hodological properties and molecular markers. This broad classification has allowed the correlation between individual neural progenitor populations and their neuronal progeny, thus contributing to probe the cellular and molecular mechanisms involved in neuronal identity determination during central nervous system (CNS) development. In this review, we discuss the contribution of the proneural genes Neurogenin2 (Neurog2) and Achaete-scute homolog 1 (Ascl1) for the specification of neuronal phenotypes in the developing neocortex, cerebellum and retina. Then, we revise recent data on astroglia cell lineage reprogramming into induced neurons using the same proneural proteins to compare the neuronal phenotypes obtained from astroglial cells originated in those CNS regions. We conclude that Ascl1 and Neurog2 have different contributions to determine neuronal fates, depending on the neural progenitor or astroglial population expressing those proneural factors. Finally, we discuss some possible explanations for these seemingly conflicting effects of Ascl1 and Neurog2 and propose future approaches to further dissect the molecular mechanisms of neuronal identity specification.
Collapse
Affiliation(s)
- Malek Chouchane
- Brain Institute, Federal University of Rio Grande do Norte, Natal 59072-970, Brazil; Neurological Surgery Department, University of California, San Francisco 94158, USA
| | - Marcos R Costa
- Brain Institute, Federal University of Rio Grande do Norte, Natal 59072-970, Brazil.
| |
Collapse
|
26
|
Transcriptional regulation of Nfix by NFIB drives astrocytic maturation within the developing spinal cord. Dev Biol 2017; 432:286-297. [PMID: 29106906 DOI: 10.1016/j.ydbio.2017.10.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 10/23/2017] [Accepted: 10/23/2017] [Indexed: 01/15/2023]
Abstract
During mouse spinal cord development, ventricular zone progenitor cells transition from producing neurons to producing glia at approximately embryonic day 11.5, a process known as the gliogenic switch. The transcription factors Nuclear Factor I (NFI) A and B initiate this developmental transition, but the contribution of a third NFI member, NFIX, remains unknown. Here, we reveal that ventricular zone progenitor cells within the spinal cord express NFIX after the onset of NFIA and NFIB expression, and after the gliogenic switch has occurred. Mice lacking NFIX exhibit normal neurogenesis within the spinal cord, and, while early astrocytic differentiation proceeds normally, aspects of terminal astrocytic differentiation are impaired. Finally, we report that, in the absence of Nfia or Nfib, there is a marked reduction in the spinal cord expression of NFIX, and that NFIB can transcriptionally activate Nfix expression in vitro. These data demonstrate that NFIX is part of the downstream transcriptional program through which NFIA and NFIB coordinate gliogenesis within the spinal cord. This hierarchical organisation of NFI protein expression and function during spinal cord gliogenesis reveals a previously unrecognised auto-regulatory mechanism within this gene family.
Collapse
|
27
|
Huang L, Chen M, Zhang W, Sun X, Liu B, Ge J. Retinoid acid and taurine promote NeuroD1-induced differentiation of induced pluripotent stem cells into retinal ganglion cells. Mol Cell Biochem 2017; 438:67-76. [PMID: 28766169 DOI: 10.1007/s11010-017-3114-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 07/15/2017] [Indexed: 01/11/2023]
Abstract
Induced pluripotent stem cells (iPSCs) possess the capacity to differentiate into multiple cell types including retinal neurons. Despite substantial progress in the transcriptional regulation of iPSC differentiation process, the efficiency of generation of retinal neurons from iPSCs is still low. In this study, we investigated the role of transcription factor NeuroD1 in the differentiation of iPSCs into retinal neurons. We observed that retrovirus-mediated NeuroD1 overexpression in iPSCs increased the efficiency of neuronal differentiation. Immunostaining analysis showed that NeuroD1 overexpression increased the expression of retina ganglion cell markers including Islet-1, Math5, Brn3b, and Thy1.2. Retinoid acid (RA) and taurine further improved the differentiation efficiency of iPSCs overexpressing NeuroD1. However, RA and taurine did not promote differentiation in the absence of NeuroD1 overexpression. Together, our study provides new evidence in transcription factor-regulated stem cell differentiation in vitro.
Collapse
Affiliation(s)
- Li Huang
- Department of Ophthalmology, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, China
| | - Mengfei Chen
- Head&Neck Surgery Department of Otolaryngology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Weizhong Zhang
- Ophthalmology Department, Sir Runrun Hospital Affiliated With Nanjing Medical University, Nanjing, 325200, China
| | - Xuerong Sun
- Institute of Aging Research, Dongguan Scientific Research Center, Guangdong Medical University, Dongguan, 523808, China
| | - Bingqian Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmologic Center, Sun Yet-sen University, Guangzhou, 510060, China
| | - Jian Ge
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmologic Center, Sun Yet-sen University, Guangzhou, 510060, China.
| |
Collapse
|
28
|
Park KU, Randazzo G, Jones KL, Brzezinski JA. Gsg1, Trnp1, and Tmem215 Mark Subpopulations of Bipolar Interneurons in the Mouse Retina. Invest Ophthalmol Vis Sci 2017; 58:1137-1150. [PMID: 28199486 PMCID: PMC5317276 DOI: 10.1167/iovs.16-19767] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Purpose How retinal bipolar cell interneurons are specified and assigned to specialized subtypes is only partially understood. In part, this is due to a lack of early pan- and subtype-specific bipolar cell markers. To discover these factors, we identified genes that were upregulated in Blimp1 (Prdm1) mutant retinas, which exhibit precocious bipolar cell development. Methods Postnatal day (P)2 retinas from Blimp1 conditional knock-out (CKO) mice and controls were processed for RNA sequencing. Genes that increased at least 45% and were statistically different between conditions were considered candidate bipolar-specific factors. Candidates were further evaluated by RT-PCR, in situ hybridization, and immunohistochemistry. Knock-in Tmem215-LacZ mice were used to better trace retinal expression. Results A comparison between Blimp1 CKO and control RNA-seq datasets revealed approximately 40 significantly upregulated genes. We characterized the expression of three genes that have no known function in the retina, Gsg1 (germ cell associated gene), Trnp1 (TMF-regulated nuclear protein), and Tmem215 (a predicted transmembrane protein). Germ cell associated gene appeared restricted to a small subset of cone bipolars while Trnp1 was seen in all ON type bipolar cells. Using Tmem215-LacZ heterozygous knock-in mice, we observed that β-galactosidase expression started early in bipolar cell development. In adults, Tmem215 was expressed by a subset of ON and OFF cone bipolar cells. Conclusions We have identified Gsg1, Tmem215, and Trnp1 as novel bipolar subtype-specific genes. The spatial and temporal pattern of their expression is consistent with a role in controlling bipolar subtype fate choice, differentiation, or physiology.
Collapse
Affiliation(s)
- Ko Uoon Park
- Department of Ophthalmology, University of Colorado Denver, Aurora, Colorado, United States
| | - Grace Randazzo
- Department of Ophthalmology, University of Colorado Denver, Aurora, Colorado, United States
| | - Kenneth L Jones
- Department of Pediatrics, Section Hematology/Oncology, University of Colorado Denver, Aurora, Colorado, United States
| | - Joseph A Brzezinski
- Department of Ophthalmology, University of Colorado Denver, Aurora, Colorado, United States
| |
Collapse
|
29
|
Chen Y, Bartanus J, Liang D, Zhu H, Breman AM, Smith JL, Wang H, Ren Z, Patel A, Stankiewicz P, Cram DS, Cheung SW, Wu L, Yu F. Characterization of chromosomal abnormalities in pregnancy losses reveals critical genes and loci for human early development. Hum Mutat 2017; 38:669-677. [PMID: 28247551 DOI: 10.1002/humu.23207] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 02/19/2017] [Accepted: 02/21/2017] [Indexed: 11/09/2022]
Abstract
Detailed characterization of chromosomal abnormalities, a common cause for congenital abnormalities and pregnancy loss, is critical for elucidating genes for human fetal development. Here, 2,186 product-of-conception samples were tested for copy-number variations (CNVs) at two clinical diagnostic centers using whole-genome sequencing and high-resolution chromosomal microarray analysis. We developed a new gene discovery approach to predict potential developmental genes and identified 275 candidate genes from CNVs detected from both datasets. Based on Mouse Genome Informatics (MGI) and Zebrafish model organism database (ZFIN), 75% of identified genes could lead to developmental defects when mutated. Genes involved in embryonic development, gene transcription, and regulation of biological processes were significantly enriched. Especially, transcription factors and gene families sharing specific protein domains predominated, which included known developmental genes such as HOX, NKX homeodomain genes, and helix-loop-helix containing HAND2, NEUROG2, and NEUROD1 as well as potential novel developmental genes. We observed that developmental genes were denser in certain chromosomal regions, enabling identification of 31 potential genomic loci with clustered genes associated with development.
Collapse
Affiliation(s)
- Yiyun Chen
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Justin Bartanus
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Desheng Liang
- State Key Lab of Medical Genetics of China Central South University, Changsha, Hunan, China
| | | | - Amy M Breman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Cytogenetics Laboratory, Baylor Miraca Genetics Laboratories, Houston, Texas
| | - Janice L Smith
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Cytogenetics Laboratory, Baylor Miraca Genetics Laboratories, Houston, Texas
| | - Hua Wang
- Hunan Maternal and Child Health Care Hospital, Changsha, Hunan, China
| | - Zhilin Ren
- Berry Genomics Corporation, Beijing, China
| | - Ankita Patel
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Cytogenetics Laboratory, Baylor Miraca Genetics Laboratories, Houston, Texas
| | - Pawel Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Cytogenetics Laboratory, Baylor Miraca Genetics Laboratories, Houston, Texas
| | | | - Sau Wai Cheung
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Cytogenetics Laboratory, Baylor Miraca Genetics Laboratories, Houston, Texas
| | - Lingqian Wu
- State Key Lab of Medical Genetics of China Central South University, Changsha, Hunan, China
| | - Fuli Yu
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Berry Genomics Corporation, Beijing, China
| |
Collapse
|
30
|
Temporal profiling of photoreceptor lineage gene expression during murine retinal development. Gene Expr Patterns 2017; 23-24:32-44. [PMID: 28288836 DOI: 10.1016/j.gep.2017.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 02/03/2017] [Accepted: 03/07/2017] [Indexed: 02/08/2023]
Abstract
Rod and cone photoreceptors are photosensitive cells in the retina that convert light to electrical signals that are transmitted to visual processing centres in the brain. During development, cones and rods are generated from a common pool of multipotent retinal progenitor cells (RPCs) that also give rise to other retinal cell types. Cones and rods differentiate in two distinct waves, peaking in mid-embryogenesis and the early postnatal period, respectively. As RPCs transition from making cones to generating rods, there are changes in the expression profiles of genes involved in photoreceptor cell fate specification and differentiation. To better understand the temporal transition from cone to rod genesis, we assessed the timing of onset and offset of expression of a panel of 11 transcription factors and 7 non-transcription factors known to function in photoreceptor development, examining their expression between embryonic day (E) 12.5 and postnatal day (P) 60. Transcription factor expression in the photoreceptor layer was observed as early as E12.5, beginning with Crx, Otx2, Rorb, Neurod1 and Prdm1 expression, followed at E15.5 with the expression of Thrb, Neurog1, Sall3 and Rxrg expression, and at P0 by Nrl and Nr2e3 expression. Of the non-transcription factors, peanut agglutinin lectin staining and cone arrestin protein were observed as early as E15.5 in the developing outer nuclear layer, while transcripts for the cone opsins Opn1mw and Opn1sw and Recoverin protein were detected in photoreceptors by P0. In contrast, Opn1mw and Opn1sw protein were not observed in cones until P7, when rod-specific Gnat1 transcripts and rhodopsin protein were also detected. We have thus identified four transitory stages during murine retina photoreceptor differentiation marked by the period of onset of expression of new photoreceptor lineage genes. By characterizing these stages, we have clarified the dynamic nature of gene expression during the period when photoreceptor identities are progressively acquired during development.
Collapse
|
31
|
Aparicio JG, Hopp H, Choi A, Mandayam Comar J, Liao VC, Harutyunyan N, Lee TC. Temporal expression of CD184(CXCR4) and CD171(L1CAM) identifies distinct early developmental stages of human retinal ganglion cells in embryonic stem cell derived retina. Exp Eye Res 2017; 154:177-189. [PMID: 27867005 PMCID: PMC5359064 DOI: 10.1016/j.exer.2016.11.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 08/29/2016] [Accepted: 11/14/2016] [Indexed: 12/29/2022]
Abstract
Human retinal ganglion cells (RGCs) derived from pluripotent stem cells (PSCs) have anticipated value for human disease study, drug screening, and therapeutic applications; however, their full potential remains underdeveloped. To characterize RGCs in human embryonic stem cell (hESC) derived retinal organoids we examined RGC markers and surface antigen expression and made comparisons to human fetal retina. RGCs in both tissues exhibited CD184 and CD171 expression and distinct expression patterns of the RGC markers BRN3 and RBPMS. The retinal progenitor cells (RPCs) of retinal organoids expressed CD184, consistent with its expression in the neuroblastic layer in fetal retina. In retinal organoids CD184 expression was enhanced in RGC competent RPCs and high CD184 expression was retained on post-mitotic RGC precursors; CD171 was detected on maturing RGCs. The differential expression timing of CD184 and CD171 permits identification and enrichment of RGCs from retinal organoids at differing maturation states from committed progenitors to differentiating neurons. These observations will facilitate molecular characterization of PSC-derived RGCs during differentiation, critical knowledge for establishing the veracity of these in vitro produced cells. Furthermore, observations made in the retinal organoid model closely parallel those in human fetal retina further validating use of retinal organoid to model early retinal development.
Collapse
Affiliation(s)
- J G Aparicio
- The Vision Center, Division of Ophthalmology, and Department of Surgery, Children's Hospital Los Angeles, Los Angeles, CA, USA.
| | - H Hopp
- The Vision Center, Division of Ophthalmology, and Department of Surgery, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - A Choi
- The Vision Center, Division of Ophthalmology, and Department of Surgery, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | | | - V C Liao
- The Vision Center, Division of Ophthalmology, and Department of Surgery, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - N Harutyunyan
- The Vision Center, Division of Ophthalmology, and Department of Surgery, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - T C Lee
- The Vision Center, Division of Ophthalmology, and Department of Surgery, Children's Hospital Los Angeles, Los Angeles, CA, USA; Department of Ophthalmology and USC Eye Institute, University of Southern California, USA
| |
Collapse
|
32
|
Chohan A, Singh U, Kumar A, Kaur J. Müller stem cell dependent retinal regeneration. Clin Chim Acta 2016; 464:160-164. [PMID: 27876464 DOI: 10.1016/j.cca.2016.11.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 11/16/2016] [Accepted: 11/18/2016] [Indexed: 12/29/2022]
Abstract
Müller Stem cells to treat ocular diseases has triggered enthusiasm across all medical and scientific communities. Recent development in the field of stem cells has widened the prospects of applying cell based therapies to regenerate ocular tissues that have been irreversibly damaged by disease or injury. Ocular tissues such as the lens and the retina are now known to possess cell having remarkable regenerative abilities. Recent studies have shown that the Müller glia, a cell found in all vertebrate retinas, is the primary source of new neurons, and therefore are considered as the cellular basis for retinal regeneration in mammalian retinas. Here, we review the current status of retinal regeneration of the human eye by Müller stem cells. This review elucidates the current status of retinal regeneration by Müller stem cells, along with major retinal degenerative diseases where these stem cells play regenerative role in retinal repair and replacement.
Collapse
Affiliation(s)
- Annu Chohan
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Usha Singh
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Atul Kumar
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Jasbir Kaur
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
| |
Collapse
|
33
|
Boije H, Shirazi Fard S, Edqvist PH, Hallböök F. Horizontal Cells, the Odd Ones Out in the Retina, Give Insights into Development and Disease. Front Neuroanat 2016; 10:77. [PMID: 27486389 PMCID: PMC4949263 DOI: 10.3389/fnana.2016.00077] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 06/21/2016] [Indexed: 01/03/2023] Open
Abstract
Thorough investigation of a neuronal population can help reveal key aspects regarding the nervous system and its development. The retinal horizontal cells have several extraordinary features making them particularly interesting for addressing questions regarding fate assignment and subtype specification. In this review we discuss and summarize data concerning the formation and diversity of horizontal cells, how morphology is correlated to molecular markers, and how fate assignment separates the horizontal lineage from the lineages of other retinal cell types. We discuss the novel and unique features of the final cell cycle of horizontal cell progenitors and how they may relate to retinoblastoma carcinogenesis.
Collapse
Affiliation(s)
- Henrik Boije
- Department of Neuroscience, Uppsala University Uppsala, Sweden
| | | | - Per-Henrik Edqvist
- Department of Immunology, Genetics and Pathology, Uppsala University Uppsala, Sweden
| | - Finn Hallböök
- Department of Neuroscience, Uppsala University Uppsala, Sweden
| |
Collapse
|
34
|
Abstract
Photoreceptors have been the most intensively studied retinal cell type. Early lineage studies showed that photoreceptors are produced by retinal progenitor cells (RPCs) that produce only photoreceptor cells and by RPCs that produce both photoreceptor cells and other retinal cell types. More recent lineage studies have shown that there are intrinsic, molecular differences among these RPCs and that these molecular differences operate in gene regulatory networks (GRNs) that lead to the choice of the rod versus the cone fate. In addition, there are GRNs that lead to the choice of a photoreceptor fate and that of another retinal cell type. An example of such a GRN is one that drives the binary fate choice between a rod photoreceptor and bipolar cell. This GRN has many elements, including both feedforward and feedback regulatory loops, highlighting the complexity of such networks. This and other examples of retinal cell fate determination are reviewed here, focusing on the events that direct the choice of rod and cone photoreceptor fate.
Collapse
Affiliation(s)
- Constance L Cepko
- Departments of Genetics and Ophthalmology, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115;
| |
Collapse
|
35
|
Taylor SM, Alvarez-Delfin K, Saade CJ, Thomas JL, Thummel R, Fadool JM, Hitchcock PF. The bHLH Transcription Factor NeuroD Governs Photoreceptor Genesis and Regeneration Through Delta-Notch Signaling. Invest Ophthalmol Vis Sci 2015; 56:7496-515. [PMID: 26580854 PMCID: PMC4654396 DOI: 10.1167/iovs.15-17616] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 10/06/2015] [Indexed: 01/08/2023] Open
Abstract
PURPOSE Photoreceptor genesis in the retina requires precise regulation of progenitor cell competence, cell cycle exit, and differentiation, although information around the mechanisms that govern these events currently is lacking. In zebrafish, the basic helix-loop-helix (bHLH) transcription factor NeuroD governs photoreceptor genesis, but the signaling pathways through which NeuroD functions are unknown. The purpose of this study was to identify these pathways, and during photoreceptor genesis, Notch signaling was investigated as the putative mediator of NeuroD function. METHODS In embryos, genetic mosaic analysis was used to determine if NeuroD functions is cell- or non-cell-autonomous. Morpholino-induced NeuroD knockdown, CRISPR/Cas9 mutation, and pharmacologic and transgenic approaches were used, followed by in situ hybridization, immunocytochemistry, and quantitative RT-PCR (qRT-PCR), to identify mechanisms through which NeuroD functions. In adults, following photoreceptor ablation and NeuroD knockdown, similar methods as above were used to identify NeuroD function during photoreceptor regeneration. RESULTS In embryos, NeuroD function is non-cell-autonomous, NeuroD knockdown increases Notch pathway gene expression, Notch inhibition rescues the NeuroD knockdown-induced deficiency in cell cycle exit but not photoreceptor maturation, and Notch activation and CRISPR/Cas9 mutation of neurod recapitulate NeuroD knockdown. In adults, NeuroD knockdown prevents cell cycle exit and photoreceptor regeneration and increases Notch pathway gene expression, and Notch inhibition rescues this phenotype. CONCLUSIONS These data demonstrate that during embryonic development, NeuroD governs photoreceptor genesis via non-cell-autonomous mechanisms and that, during photoreceptor development and regeneration, Notch signaling is a mechanistic link between NeuroD and cell cycle exit. In contrast, during embryonic development, NeuroD governs photoreceptor maturation via mechanisms that are independent of Notch signaling.
Collapse
Affiliation(s)
- Scott M. Taylor
- Department of Ophthalmology and Visual Sciences University of Michigan, W. K. Kellogg Eye Center, Ann Arbor, Michigan, United States
| | - Karen Alvarez-Delfin
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States
| | - Carole J. Saade
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States
| | - Jennifer L. Thomas
- Departments of Anatomy/Cell Biology and Ophthalmology, Wayne State University, Detroit, Michigan, United States
| | - Ryan Thummel
- Departments of Anatomy/Cell Biology and Ophthalmology, Wayne State University, Detroit, Michigan, United States
| | - James M. Fadool
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States
| | - Peter F. Hitchcock
- Department of Ophthalmology and Visual Sciences University of Michigan, W. K. Kellogg Eye Center, Ann Arbor, Michigan, United States
| |
Collapse
|
36
|
Hardwick LJA, Philpott A. Multi-site phosphorylation regulates NeuroD4 activity during primary neurogenesis: a conserved mechanism amongst proneural proteins. Neural Dev 2015; 10:15. [PMID: 26084567 PMCID: PMC4494719 DOI: 10.1186/s13064-015-0044-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 06/10/2015] [Indexed: 02/04/2023] Open
Abstract
Background Basic Helix Loop Helix (bHLH) proneural transcription factors are master regulators of neurogenesis that act at multiple stages in this process. We have previously demonstrated that multi-site phosphorylation of two members of the proneural protein family, Ngn2 and Ascl1, limits their ability to drive neuronal differentiation when cyclin-dependent kinase levels are high, as would be found in rapidly cycling cells. Here we investigate potential phospho-regulation of proneural protein NeuroD4 (also known as Xath3), the Xenopus homologue of Math3/NeuroM, that functions downstream of Ngn2 in the neurogenic cascade. Results Using the developing Xenopus embryo system, we show that NeuroD4 is expressed and phosphorylated during primary neurogenesis, and this phosphorylation limits its ability to drive neuronal differentiation. Phosphorylation of up to six serine/threonine-proline sites contributes additively to regulation of NeuroD4 proneural activity without altering neuronal subtype specification, and number rather than location of available phospho-sites is the key for limiting NeuroD4 activity. Mechanistically, a phospho-mutant NeuroD4 displays increased protein stability and enhanced chromatin binding relative to wild-type NeuroD4, resulting in transcriptional up-regulation of a range of target genes that further promote neuronal differentiation. Conclusions Multi-site phosphorylation on serine/threonine-proline pairs is a widely conserved mechanism of limiting proneural protein activity, where it is the number of phosphorylated sites, rather than their location that determines protein activity. Hence, multi-site phosphorylation is very well suited to allow co-ordination of proneural protein activity with the cellular proline-directed kinase environment. Electronic supplementary material The online version of this article (doi:10.1186/s13064-015-0044-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Laura J A Hardwick
- Department of Oncology, University of Cambridge, Hutchison/MRC Research Centre, Cambridge Biomedical Campus, Cambridge, CB2 0XZ, UK.
| | - Anna Philpott
- Department of Oncology, University of Cambridge, Hutchison/MRC Research Centre, Cambridge Biomedical Campus, Cambridge, CB2 0XZ, UK.
| |
Collapse
|
37
|
Can the ‘neuron theory’ be complemented by a universal mechanism for generic neuronal differentiation. Cell Tissue Res 2014; 359:343-84. [DOI: 10.1007/s00441-014-2049-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 10/23/2014] [Indexed: 12/19/2022]
|
38
|
Intrinsically different retinal progenitor cells produce specific types of progeny. Nat Rev Neurosci 2014; 15:615-27. [DOI: 10.1038/nrn3767] [Citation(s) in RCA: 249] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
39
|
Hao H, Li Y, Tzatzalos E, Gilbert J, Zala D, Bhaumik M, Cai L. Identification of a transient Sox5 expressing progenitor population in the neonatal ventral forebrain by a novel cis-regulatory element. Dev Biol 2014; 393:183-93. [PMID: 24954155 PMCID: PMC4167819 DOI: 10.1016/j.ydbio.2014.06.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 06/09/2014] [Accepted: 06/12/2014] [Indexed: 11/30/2022]
Abstract
Precise control of lineage-specific gene expression in the neural stem/progenitor cells is crucial for generation of the diversity of neuronal and glial cell types in the central nervous system (CNS). The mechanism underlying such gene regulation, however, is not fully elucidated. Here, we report that a 377 bp evolutionarily conserved DNA fragment (CR5), located approximately 32 kbp upstream of Olig2 transcription start site, acts as a cis-regulator for gene expression in the development of the neonatal forebrain. CR5 is active in a time-specific and brain region-restricted manner. CR5 activity is not detected in the embryonic stage, but it is exclusively in a subset of Sox5+ cells in the neonatal ventral forebrain. Furthermore, we show that Sox5 binding motif in CR5 is important for this cell-specific gene regulatory activity; mutation of Sox5 binding motif in CR5 alters reporter gene expression with different cellular composition. Together, our study provides new insights into the regulation of cell-specific gene expression during CNS development.
Collapse
Affiliation(s)
- Hailing Hao
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States
| | - Ying Li
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States
| | - Evangeline Tzatzalos
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States
| | - Jordana Gilbert
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States
| | - Dhara Zala
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States
| | - Mantu Bhaumik
- The Child Health Institute of New Jersey, 89 French Street, New Brunswick, NJ 08901, United States
| | - Li Cai
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States.
| |
Collapse
|
40
|
Mizeracka K, DeMaso CR, Cepko CL. Notch1 is required in newly postmitotic cells to inhibit the rod photoreceptor fate. Development 2013; 140:3188-97. [PMID: 23824579 DOI: 10.1242/dev.090696] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Several models of cell fate determination can be invoked to explain how single retinal progenitor cells (RPCs) produce different cell types in a terminal division. To gain insight into this process, the effects of the removal of a cell fate regulator, Notch1, were studied in newly postmitotic cells using a conditional allele of Notch1 (N1-CKO) in mice. Almost all newly postmitotic N1-CKO cells became rod photoreceptors, whereas wild-type (WT) cells achieved a variety of fates. Single cell profiling of wild-type and N1-CKO retinal cells transitioning from progenitor to differentiated states revealed differential expression of inhibitor of DNA binding factors Id1 and Id3, as well as Notch-regulated ankyrin repeat protein (Nrarp). Misexpression of Id1 and Id3 was found to be sufficient to drive production of Müller glial cells and/or RPCs. Moreover, Id1 and Id3 were shown to partially rescue the production of bipolar and Müller glial cells in the absence of Notch1 in mitotic and newly postmitotic cells. Misexpression of Nrarp, a downstream target gene and inhibitor of the Notch signaling pathway, resulted in the overproduction of rod photoreceptors at the expense of Müller glial cells. These data demonstrate that cell fate decisions can be made in newly postmitotic retinal cells, and reveal some of the regulators downstream of Notch1 that influence the choice of rod and non-rod fates. Taken together, our results begin to address how different signals downstream from a common pathway lead to different fate outcomes.
Collapse
|
41
|
Pollak J, Wilken MS, Ueki Y, Cox KE, Sullivan JM, Taylor RJ, Levine EM, Reh TA. ASCL1 reprograms mouse Muller glia into neurogenic retinal progenitors. Development 2013; 140:2619-31. [PMID: 23637330 PMCID: PMC3666387 DOI: 10.1242/dev.091355] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2013] [Indexed: 12/14/2022]
Abstract
Non-mammalian vertebrates have a robust ability to regenerate injured retinal neurons from Müller glia (MG) that activate the gene encoding the proneural factor Achaete-scute homolog 1 (Ascl1; also known as Mash1 in mammals) and de-differentiate into progenitor cells. By contrast, mammalian MG have a limited regenerative response and fail to upregulate Ascl1 after injury. To test whether ASCL1 could restore neurogenic potential to mammalian MG, we overexpressed ASCL1 in dissociated mouse MG cultures and intact retinal explants. ASCL1-infected MG upregulated retinal progenitor-specific genes and downregulated glial genes. Furthermore, ASCL1 remodeled the chromatin at its targets from a repressive to an active configuration. MG-derived progenitors differentiated into cells that exhibited neuronal morphologies, expressed retinal subtype-specific neuronal markers and displayed neuron-like physiological responses. These results indicate that a single transcription factor, ASCL1, can induce a neurogenic state in mature MG.
Collapse
Affiliation(s)
- Julia Pollak
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
- Neurobiology and Behavior Program, University of Washington, Seattle, WA 98195, USA
| | - Matthew S. Wilken
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA
| | - Yumi Ueki
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Kristen E. Cox
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Jane M. Sullivan
- Neurobiology and Behavior Program, University of Washington, Seattle, WA 98195, USA
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Russell J. Taylor
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Edward M. Levine
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA
| | - Thomas A. Reh
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
- Neurobiology and Behavior Program, University of Washington, Seattle, WA 98195, USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA
| |
Collapse
|
42
|
Mao CA, Cho JH, Wang J, Gao Z, Pan P, Tsai WW, Frishman LJ, Klein WH. Reprogramming amacrine and photoreceptor progenitors into retinal ganglion cells by replacing Neurod1 with Atoh7. Development 2013; 140:541-51. [PMID: 23293286 DOI: 10.1242/dev.085886] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The specification of the seven retinal cell types from a common pool of retina progenitor cells (RPCs) involves complex interactions between the intrinsic program and the environment. The proneural basic helix-loop-helix (bHLH) transcriptional regulators are key components for the intrinsic programming of RPCs and are essential for the formation of the diverse retinal cell types. However, the extent to which an RPC can re-adjust its inherent program and the mechanisms through which the expression of a particular bHLH factor influences RPC fate is unclear. Previously, we have shown that Neurod1 inserted into the Atoh7 locus activates the retinal ganglion cell (RGC) program in Atoh7-expressing RPCs but not in Neurod1-expressing RPCs, suggesting that Atoh7-expressing RPCs are not able to adopt the cell fate determined by Neurod1, but rather are pre-programmed to produce RGCs. Here, we show that Neurod1-expressing RPCs, which are destined to produce amacrine and photoreceptor cells, can be re-programmed into RGCs when Atoh7 is inserted into the Neurod1 locus. These results suggest that Atoh7 acts dominantly to convert a RPC subpopulation not destined for an RGC fate to adopt that fate. Thus, Atoh7-expressing and Neurod1-expressing RPCs are intrinsically different in their behavior. Additionally, ChIP-Seq analysis identified an Atoh7-dependent enhancer within the intronic region of Nrxn3. The enhancer recognized and used Atoh7 in the developing retina to regulate expression of Nrxn3, but could be forced to use Neurod1 when placed in a different regulatory context. The results indicate that Atoh7 and Neurod1 activate distinct sets of genes in vivo, despite their common DNA-binding element.
Collapse
Affiliation(s)
- Chai-An Mao
- Department of Biochemistry and Molecular Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | | | | | | | | | | | | | | |
Collapse
|
43
|
Usui A, Mochizuki Y, Iida A, Miyauchi E, Satoh S, Sock E, Nakauchi H, Aburatani H, Murakami A, Wegner M, Watanabe S. The early retinal progenitor-expressed gene Sox11 regulates the timing of the differentiation of retinal cells. Development 2013; 140:740-50. [PMID: 23318640 DOI: 10.1242/dev.090274] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Sry-related HMG box (Sox) proteins, Sox11 and Sox4 are members of the SoxC subtype. We found that Sox11 was strongly expressed in early retinal progenitor cells and that Sox4 expression began around birth, when expression of Sox11 subsided. To analyze the roles of Sox11 and Sox4 in retinal development, we perturbed their expression patterns in retinal explant cultures. Overexpression of Sox11 and Sox4 in retinal progenitors resulted in similar phenotypes: an increased number of cone cells and dramatically decreased numbers of rod cells and Müller glia. Birth-date analysis showed that cone cells were produced at a later developmental stage than that in which cone genesis normally occurs. Sox11-knockout retinas showed delayed onset and progress of differentiation of subsets of retinal cells during the embryonic period. After birth, retinal differentiation took place relatively normally, probably because of the redundant activity of Sox4, which starts to be expressed around birth. Overexpression and loss-of-function analysis failed to provide any evidence that Sox11 and Sox4 directly regulate the transcription of genes crucial to the differentiation of subsets of retinal cells. However, histone H3 acetylation of some early proneural genes was reduced in knockout retina. Thus, Sox11 may create an epigenetic state that helps to establish the competency to differentiate. Taking our findings together, we propose that the sequential expression of Sox11 and Sox4 during retinogenesis leads to the fine adjustment of retinal differentiation by helping to establish the competency of retinal progenitors.
Collapse
Affiliation(s)
- Ayumi Usui
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Boije H, Shirazi Fard S, Ring H, Hallböök F. Forkheadbox N4 (FoxN4) triggers context-dependent differentiation in the developing chick retina and neural tube. Differentiation 2013; 85:11-9. [PMID: 23314287 DOI: 10.1016/j.diff.2012.12.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 11/23/2012] [Accepted: 12/08/2012] [Indexed: 02/08/2023]
Abstract
FoxN4, a forkhead box transcription factor, is expressed in the chicken eye field and in retinal progenitor cells (RPCs) throughout development. FoxN4 labelling overlapped with that of Pax6 and Sox2, two crucial transcription factors for RPCs. Later, during neurogenesis in the retina, some cells were intensely and transiently labelled for FoxN4. These cells co-labelled for Lim1, a transcription factor expressed in early-born horizontal cells. The result suggests that high levels of FoxN4 combined with expression of Lim1 define a population of RPCs committed to the horizontal cell fate prior to their last apical mitosis. As these prospective horizontal cells develop, their FoxN4 expression is down-regulated. Previous results suggested that FoxN4 is important for the generation of horizontal and amacrine cells but that it is not sufficient for the generation of horizontal cells (Li et al., 2004). We found that over-expression of FoxN4 in embryonic day 3 chicken retina could activate horizontal cell markers Prox1 and Lim1, and that it generated numerous and ectopically located horizontal cells of both main subtypes. However, genes expressed in photoreceptors, amacrine and ganglion cells were also activated, indicating that FoxN4 triggered the expression of several differentiation factors. This effect was not exclusive for the retina but was also seen when FoxN4 was over-expressed in the mesencephalic neural tube. Combining the results from over-expression and wild-type expression data we suggest a model where a low level of FoxN4 is maintained in RPCs and that increased levels during a restricted period trigger neurogenesis and commitment of RPCs to the horizontal cell fate.
Collapse
Affiliation(s)
- H Boije
- Department of Neuroscience, Biomedical Centre, Uppsala University, Husargatan 3, Uppsala, Sweden
| | | | | | | |
Collapse
|
45
|
Reh TA. The Development of the Retina. Retina 2013. [DOI: 10.1016/b978-1-4557-0737-9.00013-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
46
|
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.
Collapse
Affiliation(s)
- Mengqing Xiang
- Center for Advanced Biotechnology and Medicine, Rutgers University, 679 Hoes Lane West, Piscataway, NJ, 08854, USA.
| |
Collapse
|
47
|
Neurogenin2 expression together with NeuroM regulates GDNF family neurotrophic factor receptor α1 (GFRα1) expression in the embryonic spinal cord. Dev Biol 2012; 370:250-63. [DOI: 10.1016/j.ydbio.2012.08.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 08/01/2012] [Accepted: 08/02/2012] [Indexed: 10/28/2022]
|
48
|
Besser M, Jagatheaswaran M, Reinhard J, Schaffelke P, Faissner A. Tenascin C regulates proliferation and differentiation processes during embryonic retinogenesis and modulates the de-differentiation capacity of Müller glia by influencing growth factor responsiveness and the extracellular matrix compartment. Dev Biol 2012; 369:163-76. [DOI: 10.1016/j.ydbio.2012.05.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 05/15/2012] [Accepted: 05/18/2012] [Indexed: 01/18/2023]
|
49
|
An essential role for RAX homeoprotein and NOTCH-HES signaling in Otx2 expression in embryonic retinal photoreceptor cell fate determination. J Neurosci 2012; 31:16792-807. [PMID: 22090505 DOI: 10.1523/jneurosci.3109-11.2011] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The molecular mechanisms underlying cell fate determination from common progenitors in the vertebrate CNS remain elusive. We previously reported that the OTX2 homeoprotein regulates retinal photoreceptor cell fate determination. While Otx2 transactivation is a pivotal process for photoreceptor cell fate determination, its transactivation mechanism in the retina is unknown. Here, we identified an evolutionarily conserved Otx2 enhancer of ∼500 bp, named embryonic enhancer locus for photoreceptor Otx2 transcription (EELPOT), which can recapitulate initial Otx2 expression in the embryonic mouse retina. We found that the RAX homeoprotein interacts with EELPOT to transactivate Otx2, mainly in the final cell cycle of retinal progenitors. Conditional inactivation of Rax results in downregulation of Otx2 expression in vivo. We also showed that NOTCH-HES signaling negatively regulates EELPOT to suppress Otx2 expression. These results suggest that the integrated activity of cell-intrinsic and -extrinsic factors on EELPOT underlies the molecular basis of photoreceptor cell fate determination in the embryonic retina.
Collapse
|
50
|
Zaghloul NA, Yan B, Moody SA. Step-wise specification of retinal stem cells during normal embryogenesis. Biol Cell 2012; 97:321-37. [PMID: 15836431 DOI: 10.1042/bc20040521] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The specification of embryonic cells to produce the retina begins at early embryonic stages as a multi-step process that gradually restricts fate potentials. First, a subset of embryonic cells becomes competent to form retina by their lack of expression of endo-mesoderm-specifying genes. From these cells, a more restricted subset is biased to form retina by virtue of their close proximity to sources of bone morphogenetic protein antagonists during neural induction. During gastrulation, the definitive RSCs (retinal stem cells) are specified as the eye field by interactions with underlying mesoderm and the expression of a network of retina-specifying genes. As the eye field is transformed into the optic vesicle and optic cup, a heterogeneous population of RPCs (retinal progenitor cells) forms to give rise to the different domains of the retina: the optic stalk, retinal pigmented epithelium and neural retina. Further diversity of RPCs appears to occur under the influences of cell-cell interactions, cytokines and combinations of regulatory genes, leading to the differentiation of a multitude of different retinal cell types. This review examines what is known about each sequential step in retinal specification during normal vertebrate development, and how that knowledge will be important to understand how RSCs might be manipulated for regenerative therapies to treat retinal diseases.
Collapse
Affiliation(s)
- Norann A Zaghloul
- Department of Anatomy and Cell Biology, The George Washington University, 2300 Eye Street, NW, Washington, DC 20037, USA
| | | | | |
Collapse
|