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Li Z, Klein JA, Rampam S, Kurzion R, Campbell NB, Patel Y, Haydar TF, Zeldich E. Asynchronous excitatory neuron development in an isogenic cortical spheroid model of Down syndrome. Front Neurosci 2022; 16:932384. [PMID: 36161168 PMCID: PMC9504873 DOI: 10.3389/fnins.2022.932384] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 07/21/2022] [Indexed: 11/17/2022] Open
Abstract
The intellectual disability (ID) in Down syndrome (DS) is thought to result from a variety of developmental deficits such as alterations in neural progenitor division, neurogenesis, gliogenesis, cortical architecture, and reduced cortical volume. However, the molecular processes underlying these neurodevelopmental changes are still elusive, preventing an understanding of the mechanistic basis of ID in DS. In this study, we used a pair of isogenic (trisomic and euploid) induced pluripotent stem cell (iPSC) lines to generate cortical spheroids (CS) that model the impact of trisomy 21 on brain development. Cortical spheroids contain neurons, astrocytes, and oligodendrocytes and they are widely used to approximate early neurodevelopment. Using single cell RNA sequencing (scRNA-seq), we uncovered cell type-specific transcriptomic changes in the trisomic CS. In particular, we found that excitatory neuron populations were most affected and that a specific population of cells with a transcriptomic profile resembling layer IV cortical neurons displayed the most profound divergence in developmental trajectory between trisomic and euploid genotypes. We also identified candidate genes potentially driving the developmental asynchrony between trisomic and euploid excitatory neurons. Direct comparison between the current isogenic CS scRNA-seq data and previously published datasets revealed several recurring differentially expressed genes between DS and control samples. Altogether, our study highlights the power and importance of cell type-specific analyses within a defined genetic background, coupled with broader examination of mixed samples, to comprehensively evaluate cellular phenotypes in the context of DS.
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Affiliation(s)
- Zhen Li
- Center for Neuroscience Research, Children’s National Hospital, Washington, DC, United States
| | - Jenny A. Klein
- Center for Neuroscience Research, Children’s National Hospital, Washington, DC, United States
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
| | - Sanjeev Rampam
- Department of Biomedical Engineering, Boston University, Boston, MA, United States
| | - Ronni Kurzion
- Department of Chemistry, Boston University, Boston, MA, United States
| | | | - Yesha Patel
- Department of Anatomy and Neurobiology, Boston University, Boston, MA, United States
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, United States
| | - Tarik F. Haydar
- Center for Neuroscience Research, Children’s National Hospital, Washington, DC, United States
| | - Ella Zeldich
- Department of Anatomy and Neurobiology, Boston University, Boston, MA, United States
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Harb K, Richter M, Neelagandan N, Magrinelli E, Harfoush H, Kuechler K, Henis M, Hermanns-Borgmeyer I, Calderon de Anda F, Duncan K. Pum2 and TDP-43 refine area-specific cytoarchitecture post-mitotically and modulate translation of Sox5, Bcl11b, and Rorb mRNAs in developing mouse neocortex. eLife 2022; 11:55199. [PMID: 35262486 PMCID: PMC8906809 DOI: 10.7554/elife.55199] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 02/25/2022] [Indexed: 12/15/2022] Open
Abstract
In the neocortex, functionally distinct areas process specific types of information. Area identity is established by morphogens and transcriptional master regulators, but downstream mechanisms driving area-specific neuronal specification remain unclear. Here, we reveal a role for RNA-binding proteins in defining area-specific cytoarchitecture. Mice lacking Pum2 or overexpressing human TDP-43 show apparent ‘motorization’ of layers IV and V of primary somatosensory cortex (S1), characterized by dramatic expansion of cells co-expressing Sox5 and Bcl11b/Ctip2, a hallmark of subcerebral projection neurons, at the expense of cells expressing the layer IV neuronal marker Rorβ. Moreover, retrograde labeling experiments with cholera toxin B in Pum2; Emx1-Cre and TDP43A315T mice revealed a corresponding increase in subcerebral connectivity of these neurons in S1. Intriguingly, other key features of somatosensory area identity are largely preserved, suggesting that Pum2 and TDP-43 may function in a downstream program, rather than controlling area identity per se. Transfection of primary neurons and in utero electroporation (IUE) suggest cell-autonomous and post-mitotic modulation of Sox5, Bcl11b/Ctip2, and Rorβ levels. Mechanistically, we find that Pum2 and TDP-43 directly interact with and affect the translation of mRNAs encoding Sox5, Bcl11b/Ctip2, and Rorβ. In contrast, effects on the levels of these mRNAs were not detectable in qRT-PCR or single-molecule fluorescent in situ hybridization assays, and we also did not detect effects on their splicing or polyadenylation patterns. Our results support the notion that post-transcriptional regulatory programs involving translational regulation and mediated by Pum2 and TDP-43 contribute to elaboration of area-specific neuronal identity and connectivity in the neocortex.
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Affiliation(s)
- Kawssar Harb
- Neuronal Translational Control Group, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Melanie Richter
- Institute of Developmental Neurophysiology, Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nagammal Neelagandan
- Neuronal Translational Control Group, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Elia Magrinelli
- Department of Basic Neuroscience, University of Geneva, Geneva, Switzerland
| | - Hend Harfoush
- Neuronal Translational Control Group, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Katrin Kuechler
- Neuronal Translational Control Group, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Melad Henis
- Institute of Developmental Neurophysiology, Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Department of Anatomy and Histology, Faculty of Veterinary Medicine, New Valley University, New Valley, Egypt
| | - Irm Hermanns-Borgmeyer
- Transgenic Service Group, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Froylan Calderon de Anda
- Institute of Developmental Neurophysiology, Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Kent Duncan
- Neuronal Translational Control Group, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
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