1
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Patowary A, Zhang P, Jops C, Vuong CK, Ge X, Hou K, Kim M, Gong N, Margolis M, Vo D, Wang X, Liu C, Pasaniuc B, Li JJ, Gandal MJ, de la Torre-Ubieta L. Developmental isoform diversity in the human neocortex informs neuropsychiatric risk mechanisms. Science 2024; 384:eadh7688. [PMID: 38781356 DOI: 10.1126/science.adh7688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 03/13/2024] [Indexed: 05/25/2024]
Abstract
RNA splicing is highly prevalent in the brain and has strong links to neuropsychiatric disorders; yet, the role of cell type-specific splicing and transcript-isoform diversity during human brain development has not been systematically investigated. In this work, we leveraged single-molecule long-read sequencing to deeply profile the full-length transcriptome of the germinal zone and cortical plate regions of the developing human neocortex at tissue and single-cell resolution. We identified 214,516 distinct isoforms, of which 72.6% were novel (not previously annotated in Gencode version 33), and uncovered a substantial contribution of transcript-isoform diversity-regulated by RNA binding proteins-in defining cellular identity in the developing neocortex. We leveraged this comprehensive isoform-centric gene annotation to reprioritize thousands of rare de novo risk variants and elucidate genetic risk mechanisms for neuropsychiatric disorders.
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Affiliation(s)
- Ashok Patowary
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA 90095, USA
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Pan Zhang
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA 90095, USA
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Connor Jops
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Lifespan Brain Institute at Penn Med and the Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Celine K Vuong
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA 90095, USA
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Xinzhou Ge
- Department of Statistics, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Kangcheng Hou
- Bioinformatics Interdepartmental Program, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Minsoo Kim
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Naihua Gong
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael Margolis
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Daniel Vo
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Lifespan Brain Institute at Penn Med and the Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Xusheng Wang
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38103, USA
- Center for Proteomics and Metabolomics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Chunyu Liu
- Department of Psychiatry, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China
| | - Bogdan Pasaniuc
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Bioinformatics Interdepartmental Program, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Institute for Precision Health, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Computational Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Jingyi Jessica Li
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Statistics, University of California Los Angeles, Los Angeles, CA 90095, USA
- Bioinformatics Interdepartmental Program, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Computational Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Biostatistics, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Michael J Gandal
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA 90095, USA
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Lifespan Brain Institute at Penn Med and the Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Luis de la Torre-Ubieta
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA 90095, USA
- Intellectual and Developmental Disabilities Research Center, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA 90095, USA
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2
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Di Bella DJ, Domínguez-Iturza N, Brown JR, Arlotta P. Making Ramón y Cajal proud: Development of cell identity and diversity in the cerebral cortex. Neuron 2024:S0896-6273(24)00282-4. [PMID: 38754415 DOI: 10.1016/j.neuron.2024.04.021] [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: 12/15/2023] [Revised: 03/28/2024] [Accepted: 04/18/2024] [Indexed: 05/18/2024]
Abstract
Since the beautiful images of Santiago Ramón y Cajal provided a first glimpse into the immense diversity and complexity of cell types found in the cerebral cortex, neuroscience has been challenged and inspired to understand how these diverse cells are generated and how they interact with each other to orchestrate the development of this remarkable tissue. Some fundamental questions drive the field's quest to understand cortical development: what are the mechanistic principles that govern the emergence of neuronal diversity? How do extrinsic and intrinsic signals integrate with physical forces and activity to shape cell identity? How do the diverse populations of neurons and glia influence each other during development to guarantee proper integration and function? The advent of powerful new technologies to profile and perturb cortical development at unprecedented resolution and across a variety of modalities has offered a new opportunity to integrate past knowledge with brand new data. Here, we review some of this progress using cortical excitatory projection neurons as a system to draw out general principles of cell diversification and the role of cell-cell interactions during cortical development.
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Affiliation(s)
- Daniela J Di Bella
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
| | - Nuria Domínguez-Iturza
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
| | - Juliana R Brown
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Paola Arlotta
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
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3
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Liu J, Mosti F, Zhao HT, Sotelo-Fonseca JE, Escobar-Tomlienovich CF, Lollis D, Musso CM, Mao Y, Massri AJ, Doll HM, Sousa AM, Wray GA, Schmidt E, Silver DL. A human-specific enhancer fine-tunes radial glia potency and corticogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.10.588953. [PMID: 38645099 PMCID: PMC11030412 DOI: 10.1101/2024.04.10.588953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Humans evolved an extraordinarily expanded and complex cerebral cortex, associated with developmental and gene regulatory modifications 1-3 . Human accelerated regions (HARs) are highly conserved genomic sequences with human-specific nucleotide substitutions. Although there are thousands of annotated HARs, their functional contribution to human-specific cortical development is largely unknown 4,5 . HARE5 is a HAR transcriptional enhancer of the WNT signaling receptor Frizzled8 (FZD8) active during brain development 6 . Here, using genome-edited mouse and primate models, we demonstrate that human (Hs) HARE5 fine-tunes cortical development and connectivity by controlling the proliferative and neurogenic capacity of neural progenitor cells (NPCs). Hs-HARE5 knock-in mice have significantly enlarged neocortices containing more neurons. By measuring neural dynamics in vivo we show these anatomical features correlate with increased functional independence between cortical regions. To understand the underlying developmental mechanisms, we assess progenitor fate using live imaging, lineage analysis, and single-cell RNA sequencing. This reveals Hs-HARE5 modifies radial glial progenitor behavior, with increased self-renewal at early developmental stages followed by expanded neurogenic potential. We use genome-edited human and chimpanzee (Pt) NPCs and cortical organoids to assess the relative enhancer activity and function of Hs-HARE5 and Pt-HARE5. Using these orthogonal strategies we show four human-specific variants in HARE5 drive increased enhancer activity which promotes progenitor proliferation. These findings illustrate how small changes in regulatory DNA can directly impact critical signaling pathways and brain development. Our study uncovers new functions for HARs as key regulatory elements crucial for the expansion and complexity of the human cerebral cortex.
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4
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Chittavanich P, Saengwimol D, Roytrakul S, Rojanaporn D, Chaitankar V, Srimongkol A, Anurathapan U, Hongeng S, Kaewkhaw R. Ceftriaxone exerts antitumor effects in MYCN-driven retinoblastoma and neuroblastoma by targeting DDX3X for translation repression. Mol Oncol 2024; 18:918-938. [PMID: 37975412 PMCID: PMC10994227 DOI: 10.1002/1878-0261.13553] [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: 05/16/2023] [Revised: 10/13/2023] [Accepted: 11/15/2023] [Indexed: 11/19/2023] Open
Abstract
MYCN proto-oncogene, bHLH transcription factor (MYCN) amplification is associated with aggressive retinoblastoma (RB) and neuroblastoma (NB) cancer recurrence that is resistant to chemotherapies. Therefore, there is an urgent need to identify new therapeutic tools. This study aimed to evaluate the potential repurposing of ceftriaxone for the treatment of MYCN-amplified RB and NB, based on the clinical observations that the drug was serendipitously found to decrease the volume of the MYCN-driven RB subtype. Using patient-derived tumor organoids and tumor cell lines, we demonstrated that ceftriaxone is a potent and selective growth inhibitor targeting MYCN-driven RB and NB cells. Profiling of drug-induced transcriptomic changes, cell-cycle progression, and apoptotic death indicated cell-cycle arrest and death of drug-treated MYCN-amplified tumor cells. Drug target identification, using an affinity-based proteomic and molecular docking approach, and functional studies of the target proteins revealed that ceftriaxone targeted DEAD-box helicase 3 X-linked (DDX3X), thereby inhibiting translation in MYCN-amplified tumors but not in MYCN-nonamplified cells. The data suggest the feasibility of repurposing ceftriaxone as an anticancer drug and provide insights into the mechanism of drug action, highlighting DDX3X as a potential target for treating MYCN-driven tumors.
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Affiliation(s)
- Pamorn Chittavanich
- Program in Translational Medicine, Faculty of Medicine Ramathibodi HospitalMahidol UniversityBangkokThailand
| | - Duangporn Saengwimol
- Research Center, Faculty of Medicine Ramathibodi HospitalMahidol UniversityBangkokThailand
| | - Sittiruk Roytrakul
- Functional Proteomics Technology Laboratory, National Center for Genetic Engineering and BiotechnologyNational Science and Technology Development AgencyPathum ThaniThailand
| | - Duangnate Rojanaporn
- Department of Ophthalmology, Faculty of Medicine Ramathibodi HospitalMahidol UniversityBangkokThailand
| | - Vijender Chaitankar
- Biodata Mining and Discovery Section, National Institute of Arthritis and Musculoskeletal and Skin DiseasesNational Institutes of HealthBethesdaMDUSA
| | - Atthapol Srimongkol
- Research Center, Faculty of Medicine Ramathibodi HospitalMahidol UniversityBangkokThailand
| | - Usanarat Anurathapan
- Department of Pediatrics, Faculty of Medicine Ramathibodi HospitalMahidol UniversityBangkokThailand
| | - Suradej Hongeng
- Department of Pediatrics, Faculty of Medicine Ramathibodi HospitalMahidol UniversityBangkokThailand
| | - Rossukon Kaewkhaw
- Program in Translational Medicine, Faculty of Medicine Ramathibodi HospitalMahidol UniversityBangkokThailand
- Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi HospitalMahidol UniversitySamut PrakanThailand
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5
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Verma SK, Kuyumcu-Martinez MN. RNA binding proteins in cardiovascular development and disease. Curr Top Dev Biol 2024; 156:51-119. [PMID: 38556427 DOI: 10.1016/bs.ctdb.2024.01.007] [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] [Indexed: 04/02/2024]
Abstract
Congenital heart disease (CHD) is the most common birth defect affecting>1.35 million newborn babies worldwide. CHD can lead to prenatal, neonatal, postnatal lethality or life-long cardiac complications. RNA binding protein (RBP) mutations or variants are emerging as contributors to CHDs. RBPs are wizards of gene regulation and are major contributors to mRNA and protein landscape. However, not much is known about RBPs in the developing heart and their contributions to CHD. In this chapter, we will discuss our current knowledge about specific RBPs implicated in CHDs. We are in an exciting era to study RBPs using the currently available and highly successful RNA-based therapies and methodologies. Understanding how RBPs shape the developing heart will unveil their contributions to CHD. Identifying their target RNAs in the embryonic heart will ultimately lead to RNA-based treatments for congenital heart disease.
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Affiliation(s)
- Sunil K Verma
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine Charlottesville, VA, United States.
| | - Muge N Kuyumcu-Martinez
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine Charlottesville, VA, United States; Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, United States; University of Virginia Cancer Center, Charlottesville, VA, United States.
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6
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Zhang H, Mañán-Mejías PM, Miles HN, Putnam AA, MacGillivray LR, Ricke WA. DDX3X and Stress Granules: Emerging Players in Cancer and Drug Resistance. Cancers (Basel) 2024; 16:1131. [PMID: 38539466 PMCID: PMC10968774 DOI: 10.3390/cancers16061131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 03/09/2024] [Accepted: 03/11/2024] [Indexed: 05/02/2024] Open
Abstract
The DEAD (Asp-Glu-Ala-Asp)-box helicase 3 X-linked (DDX3X) protein participates in many aspects of mRNA metabolism and stress granule (SG) formation. DDX3X has also been associated with signal transduction and cell cycle regulation that are important in maintaining cellular homeostasis. Malfunctions of DDX3X have been implicated in multiple cancers, including brain cancer, leukemia, prostate cancer, and head and neck cancer. Recently, literature has reported SG-associated cancer drug resistance, which correlates with a negative disease prognosis. Based on the connections between DDX3X, SG formation, and cancer pathology, targeting DDX3X may be a promising direction for cancer therapeutics development. In this review, we describe the biological functions of DDX3X in terms of mRNA metabolism, signal transduction, and cell cycle regulation. Furthermore, we summarize the contributions of DDX3X in SG formation and cellular stress adaptation. Finally, we discuss the relationships of DDX3X, SG, and cancer drug resistance, and discuss the current research progress of several DDX3X inhibitors for cancer treatment.
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Affiliation(s)
- Han Zhang
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Paula M. Mañán-Mejías
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Hannah N. Miles
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Andrea A. Putnam
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | | | - William A. Ricke
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA
- Department of Urology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
- George M. O’Brien Urology Research Center of Excellence, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
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7
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Jowhar Z, Xu A, Venkataramanan S, Dossena F, Hoye ML, Silver DL, Floor SN, Calviello L. A ubiquitous GC content signature underlies multimodal mRNA regulation by DDX3X. Mol Syst Biol 2024; 20:276-290. [PMID: 38273160 PMCID: PMC10912769 DOI: 10.1038/s44320-024-00013-0] [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: 11/27/2023] [Revised: 12/21/2023] [Accepted: 01/03/2024] [Indexed: 01/27/2024] Open
Abstract
The road from transcription to protein synthesis is paved with many obstacles, allowing for several modes of post-transcriptional regulation of gene expression. A fundamental player in mRNA biology is DDX3X, an RNA binding protein that canonically regulates mRNA translation. By monitoring dynamics of mRNA abundance and translation following DDX3X depletion, we observe stabilization of translationally suppressed mRNAs. We use interpretable statistical learning models to uncover GC content in the coding sequence as the major feature underlying RNA stabilization. This result corroborates GC content-related mRNA regulation detectable in other studies, including hundreds of ENCODE datasets and recent work focusing on mRNA dynamics in the cell cycle. We provide further evidence for mRNA stabilization by detailed analysis of RNA-seq profiles in hundreds of samples, including a Ddx3x conditional knockout mouse model exhibiting cell cycle and neurogenesis defects. Our study identifies a ubiquitous feature underlying mRNA regulation and highlights the importance of quantifying multiple steps of the gene expression cascade, where RNA abundance and protein production are often uncoupled.
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Affiliation(s)
- Ziad Jowhar
- Department of Cell and Tissue Biology, UCSF, San Francisco, USA
- Medical Scientist Training Program, University of California, San Francisco, San Francisco, CA, 94158, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Albert Xu
- Department of Cell and Tissue Biology, UCSF, San Francisco, USA
- Medical Scientist Training Program, University of California, San Francisco, San Francisco, CA, 94158, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, 94158, USA
| | | | | | - Mariah L Hoye
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, USA
| | - Debra L Silver
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, USA
- Department of Cell Biology, Duke University Medical Center, Durham, USA
- Duke Regeneration Center, Duke University Medical Center, Durham, USA
- Department of Neurobiology, Duke University Medical Center, Durham, USA
- Duke Institute for Brain Sciences, Duke University Medical Center, Durham, USA
| | - Stephen N Floor
- Department of Cell and Tissue Biology, UCSF, San Francisco, USA.
- Helen Diller Family Comprehensive Cancer Center, San Francisco, USA.
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8
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Rosa E Silva I, Smetana JHC, de Oliveira JF. A comprehensive review on DDX3X liquid phase condensation in health and neurodevelopmental disorders. Int J Biol Macromol 2024; 259:129330. [PMID: 38218270 DOI: 10.1016/j.ijbiomac.2024.129330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/22/2023] [Accepted: 01/06/2024] [Indexed: 01/15/2024]
Abstract
DEAD-box helicases are global regulators of liquid-liquid phase separation (LLPS), a process that assembles membraneless organelles inside cells. An outstanding member of the DEAD-box family is DDX3X, a multi-functional protein that plays critical roles in RNA metabolism, including RNA transcription, splicing, nucleocytoplasmic export, and translation. The diverse functions of DDX3X result from its ability to bind and remodel RNA in an ATP-dependent manner. This capacity enables the protein to act as an RNA chaperone and an RNA helicase, regulating ribonucleoprotein complex assembly. DDX3X and its orthologs from mouse, yeast (Ded1), and C. elegans (LAF-1) can undergo LLPS, driving the formation of neuronal granules, stress granules, processing bodies or P-granules. DDX3X has been related to several human conditions, including neurodevelopmental disorders, such as intellectual disability and autism spectrum disorder. Although the research into the pathogenesis of aberrant biomolecular condensation in neurodegenerative diseases is increasing rapidly, the role of LLPS in neurodevelopmental disorders is underexplored. This review summarizes current findings relevant for DDX3X phase separation in neurodevelopment and examines how disturbances in the LLPS process can be related to neurodevelopmental disorders.
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Affiliation(s)
- Ivan Rosa E Silva
- Brazilian Biosciences National Laboratory, Center for Research in Energy and Materials, Campinas, SP, Brazil
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9
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Jowhar Z, Xu A, Venkataramanan S, Dossena F, Hoye ML, Silver DL, Floor SN, Calviello L. A ubiquitous GC content signature underlies multimodal mRNA regulation by DDX3X. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.11.540322. [PMID: 37214951 PMCID: PMC10197686 DOI: 10.1101/2023.05.11.540322] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The road from transcription to protein synthesis is paved with many obstacles, allowing for several modes of post-transcriptional regulation of gene expression. A fundamental player in mRNA biology is DDX3X, an RNA binding protein that canonically regulates mRNA translation. By monitoring dynamics of mRNA abundance and translation following DDX3X depletion, we observe stabilization of translationally suppressed mRNAs. We use interpretable statistical learning models to uncover GC content in the coding sequence as the major feature underlying RNA stabilization. This result corroborates GC content-related mRNA regulation detectable in other studies, including hundreds of ENCODE datasets and recent work focusing on mRNA dynamics in the cell cycle. We provide further evidence for mRNA stabilization by detailed analysis of RNA-seq profiles in hundreds of samples, including a Ddx3x conditional knockout mouse model exhibiting cell cycle and neurogenesis defects. Our study identifies a ubiquitous feature underlying mRNA regulation and highlights the importance of quantifying multiple steps of the gene expression cascade, where RNA abundance and protein production are often uncoupled.
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Affiliation(s)
- Ziad Jowhar
- Department of Cell and Tissue Biology, UCSF, San Francisco, United States
- Medical Scientist Training Program, University of California, San Francisco, San Francisco, CA 94158, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Albert Xu
- Department of Cell and Tissue Biology, UCSF, San Francisco, United States
- Medical Scientist Training Program, University of California, San Francisco, San Francisco, CA 94158, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | | | | | - Mariah L Hoye
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States
| | - Debra L Silver
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States
- Department of Cell Biology, Duke University Medical Center, Durham, United States
- Duke Regeneration Center, Duke University Medical Center, Durham, United States
- Department of Neurobiology, Duke University Medical Center, Durham, United States
- Duke Institute for Brain Sciences, Duke University Medical Center, Durham, United States
| | - Stephen N Floor
- Department of Cell and Tissue Biology, UCSF, San Francisco, United States
- Helen Diller Family Comprehensive Cancer Center, San Francisco, United States
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10
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Patowary A, Zhang P, Jops C, Vuong CK, Ge X, Hou K, Kim M, Gong N, Margolis M, Vo D, Wang X, Liu C, Pasaniuc B, Li JJ, Gandal MJ, de la Torre-Ubieta L. Developmental isoform diversity in the human neocortex informs neuropsychiatric risk mechanisms. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.25.534016. [PMID: 36993726 PMCID: PMC10055310 DOI: 10.1101/2023.03.25.534016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
RNA splicing is highly prevalent in the brain and has strong links to neuropsychiatric disorders, yet the role of cell-type-specific splicing or transcript-isoform diversity during human brain development has not been systematically investigated. Here, we leveraged single-molecule long-read sequencing to deeply profile the full-length transcriptome of the germinal zone (GZ) and cortical plate (CP) regions of the developing human neocortex at tissue and single-cell resolution. We identified 214,516 unique isoforms, of which 72.6% are novel (unannotated in Gencode-v33), and uncovered a substantial contribution of transcript-isoform diversity, regulated by RNA binding proteins, in defining cellular identity in the developing neocortex. We leveraged this comprehensive isoform-centric gene annotation to re-prioritize thousands of rare de novo risk variants and elucidate genetic risk mechanisms for neuropsychiatric disorders. One-Sentence Summary A cell-specific atlas of gene isoform expression helps shape our understanding of brain development and disease. Structured Abstract INTRODUCTION: The development of the human brain is regulated by precise molecular and genetic mechanisms driving spatio-temporal and cell-type-specific transcript expression programs. Alternative splicing, a major mechanism increasing transcript diversity, is highly prevalent in the human brain, influences many aspects of brain development, and has strong links to neuropsychiatric disorders. Despite this, the cell-type-specific transcript-isoform diversity of the developing human brain has not been systematically investigated.RATIONALE: Understanding splicing patterns and isoform diversity across the developing neocortex has translational relevance and can elucidate genetic risk mechanisms in neurodevelopmental disorders. However, short-read sequencing, the prevalent technology for transcriptome profiling, is not well suited to capturing alternative splicing and isoform diversity. To address this, we employed third-generation long-read sequencing, which enables capture and sequencing of complete individual RNA molecules, to deeply profile the full-length transcriptome of the germinal zone (GZ) and cortical plate (CP) regions of the developing human neocortex at tissue and single-cell resolution.RESULTS: We profiled microdissected GZ and CP regions of post-conception week (PCW) 15-17 human neocortex in bulk and at single-cell resolution across six subjects using high-fidelity long-read sequencing (PacBio IsoSeq). We identified 214,516 unique isoforms, of which 72.6% were novel (unannotated in Gencode), and >7,000 novel exons, expanding the proteome by 92,422 putative proteoforms. We uncovered thousands of isoform switches during cortical neurogenesis predicted to impact RNA regulatory domains or protein structure and implicating previously uncharacterized RNA-binding proteins in cellular identity and neuropsychiatric disease. At the single-cell level, early-stage excitatory neurons exhibited the greatest isoform diversity, and isoform-centric single-cell clustering led to the identification of previously uncharacterized cell states. We systematically assessed the contribution of transcriptomic features, and localized cell and spatio-temporal transcript expression signatures across neuropsychiatric disorders, revealing predominant enrichments in dynamic isoform expression and utilization patterns and that the number and complexity of isoforms per gene is strongly predictive of disease. Leveraging this resource, we re-prioritized thousands of rare de novo risk variants associated with autism spectrum disorders (ASD), intellectual disability (ID), and neurodevelopmental disorders (NDDs), more broadly, to potentially more severe consequences and revealed a larger proportion of cryptic splice variants with the expanded transcriptome annotation provided in this study.CONCLUSION: Our study offers a comprehensive landscape of isoform diversity in the human neocortex during development. This extensive cataloging of novel isoforms and splicing events sheds light on the underlying mechanisms of neurodevelopmental disorders and presents an opportunity to explore rare genetic variants linked to these conditions. The implications of our findings extend beyond fundamental neuroscience, as they provide crucial insights into the molecular basis of developmental brain disorders and pave the way for targeted therapeutic interventions. To facilitate exploration of this dataset we developed an online portal ( https://sciso.gandallab.org/ ).
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Venus S, Tandjigora K, Jankowsky E. The Viral Protein K7 Inhibits Biochemical Activities and Condensate Formation by the DEAD-box Helicase DDX3X. J Mol Biol 2023; 435:168217. [PMID: 37517790 PMCID: PMC10528715 DOI: 10.1016/j.jmb.2023.168217] [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: 03/10/2023] [Revised: 06/17/2023] [Accepted: 07/24/2023] [Indexed: 08/01/2023]
Abstract
The DEAD-box RNA helicase DDX3X promotes translation initiation and associates with stress granules. A range of diverse viruses produce proteins that target DDX3X, including hepatitis C, dengue, vaccinia, and influenza A. The interaction of some of these viral proteins with DDX3X has been shown to affect antiviral intracellular signaling, but it is unknown whether and how viral proteins impact the biochemical activities of DDX3X and its physical roles in cells. Here we show that the protein K7 from vaccinia virus, which binds to an intrinsically disordered region in the N-terminus of DDX3X, inhibits RNA helicase and RNA-stimulated ATPase activities, as well as liquid-liquid phase separation of DDX3X in vitro. We demonstrate in HCT 116 cells that K7 inhibits association of DDX3X with stress granules, as well as the formation of aberrant granules induced by expression of DDX3X with a point mutation linked to medulloblastoma and DDX3X syndrome. The results show that targeting of the intrinsically disordered N-terminus is an effective viral strategy to modulate the biochemical functions and subcellular localization of DDX3X. Our findings also have potential therapeutic implications for diseases linked to aberrant DDX3X granule formation.
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Affiliation(s)
- Sarah Venus
- Center for RNA Science and Therapeutics, Department of Biochemistry, Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44016, United States
| | - Kaba Tandjigora
- Center for RNA Science and Therapeutics, Department of Biochemistry, Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44016, United States
| | - Eckhard Jankowsky
- Center for RNA Science and Therapeutics, Department of Biochemistry, Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44016, United States.
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12
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Gadek M, Sherr EH, Floor SN. The variant landscape and function of DDX3X in cancer and neurodevelopmental disorders. Trends Mol Med 2023; 29:726-739. [PMID: 37422363 DOI: 10.1016/j.molmed.2023.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 06/12/2023] [Accepted: 06/14/2023] [Indexed: 07/10/2023]
Abstract
RNA molecules rely on proteins across their life cycle. DDX3X encodes an X-linked DEAD-box RNA helicase with a Y-linked paralog, DDX3Y. DDX3X is central to the RNA life cycle and is implicated in many conditions, including cancer and the neurodevelopmental disorder DDX3X syndrome. DDX3X-linked conditions often exhibit sex differences, possibly due to differences between expression or function of the X- and Y-linked paralogs DDX3X and DDX3Y. DDX3X-related diseases have different mutational landscapes, indicating different roles of DDX3X. Understanding the role of DDX3X in normal and disease states will inform the understanding of DDX3X in disease. We review the function of DDX3X and DDX3Y, discuss how mutation type and sex bias contribute to human diseases involving DDX3X, and review possible DDX3X-targeting treatments.
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Affiliation(s)
- Margaret Gadek
- Department of Cell and Tissue Biology, University of California, San Francisco, CA 94143, USA
| | - Elliott H Sherr
- Department of Neurology, University of California, San Francisco, CA 94143, USA
| | - Stephen N Floor
- Department of Cell and Tissue Biology, University of California, San Francisco, CA 94143, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA 94143, USA.
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Lupan BM, Solecki RA, Musso CM, Alsina FC, Silver DL. The exon junction complex component EIF4A3 is essential for mouse and human cortical progenitor mitosis and neurogenesis. Development 2023; 150:dev201619. [PMID: 37139782 PMCID: PMC10233715 DOI: 10.1242/dev.201619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 04/24/2023] [Indexed: 05/05/2023]
Abstract
Mutations in components of the exon junction complex (EJC) are associated with neurodevelopment and disease. In particular, reduced levels of the RNA helicase EIF4A3 cause Richieri-Costa-Pereira syndrome (RCPS) and copy number variations are linked to intellectual disability. Consistent with this, Eif4a3 haploinsufficient mice are microcephalic. Altogether, this implicates EIF4A3 in cortical development; however, the underlying mechanisms are poorly understood. Here, we use mouse and human models to demonstrate that EIF4A3 promotes cortical development by controlling progenitor mitosis, cell fate and survival. Eif4a3 haploinsufficiency in mice causes extensive cell death and impairs neurogenesis. Using Eif4a3;p53 compound mice, we show that apoptosis has the most impact on early neurogenesis, while additional p53-independent mechanisms contribute to later stages. Live imaging of mouse and human neural progenitors reveals that Eif4a3 controls mitosis length, which influences progeny fate and viability. These phenotypes are conserved, as cortical organoids derived from RCPS iPSCs exhibit aberrant neurogenesis. Finally, using rescue experiments we show that EIF4A3 controls neuron generation via the EJC. Altogether, our study demonstrates that EIF4A3 mediates neurogenesis by controlling mitosis duration and cell survival, implicating new mechanisms that underlie EJC-mediated disorders.
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Affiliation(s)
- Bianca M. Lupan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Rachel A. Solecki
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Camila M. Musso
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Fernando C. Alsina
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Debra L. Silver
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
- Departments of Cell Biology and Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
- Duke Institute for Brain Sciences and Duke Regeneration Center, Duke University Medical Center, Durham, NC 27710, USA
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Dorsey SG, Mocci E, Lane MV, Krueger BK. Rapid effects of valproic acid on the fetal brain transcriptome: Implications for brain development and autism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.01.538959. [PMID: 37205520 PMCID: PMC10187231 DOI: 10.1101/2023.05.01.538959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
There is an increased incidence of autism among the children of women who take the anti-epileptic, mood stabilizing drug, valproic acid (VPA) during pregnancy; moreover, exposure to VPA in utero causes autistic-like symptoms in rodents and non-human primates. Analysis of RNAseq data obtained from fetal mouse brains 3 hr after VPA administration revealed that VPA significantly [p(FDR) ≤ 0.025] increased or decreased the expression of approximately 7,300 genes. No significant sex differences in VPA-induced gene expression were observed. Expression of genes associated with neurodevelopmental disorders such as autism as well as neurogenesis, axon growth and synaptogenesis, GABAergic, glutaminergic and dopaminergic synaptic transmission, perineuronal nets, and circadian rhythms was dysregulated by VPA. Moreover, expression of 400 autism risk genes was significantly altered by VPA as was expression of 247 genes that have been reported to play fundamental roles in the development of the nervous system, but are not linked to autism by GWAS. The goal of this study was to identify mouse genes that are: (a) significantly up- or down-regulated by VPA in the fetal brain and (b) known to be associated with autism and/or to play a role in embryonic neurodevelopmental processes, perturbation of which has the potential to alter brain connectivity in the postnatal and adult brain. The set of genes meeting these criteria provides potential targets for future hypothesis-driven approaches to elucidating the proximal underlying causes of defective brain connectivity in neurodevelopmental disorders such as autism.
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15
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Ocañas SR, Ansere VA, Kellogg CM, Isola JVV, Chucair-Elliott AJ, Freeman WM. Chromosomal and gonadal factors regulate microglial sex effects in the aging brain. Brain Res Bull 2023; 195:157-171. [PMID: 36804773 PMCID: PMC10810555 DOI: 10.1016/j.brainresbull.2023.02.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 02/10/2023] [Accepted: 02/14/2023] [Indexed: 02/17/2023]
Abstract
Biological sex contributes to phenotypic sex effects through genetic (sex chromosomal) and hormonal (gonadal) mechanisms. There are profound sex differences in the prevalence and progression of age-related brain diseases, including neurodegenerative diseases. Inflammation of neural tissue is one of the most consistent age-related phenotypes seen with healthy aging and disease. The pro-inflammatory environment of the aging brain has primarily been attributed to microglial reactivity and adoption of heterogeneous reactive states dependent upon intrinsic (i.e., sex) and extrinsic (i.e., age, disease state) factors. Here, we review sex effects in microglia across the lifespan, explore potential genetic and hormonal molecular mechanisms of microglial sex effects, and discuss currently available models and methods to study sex effects in the aging brain. Despite recent attention to this area, significant further research is needed to mechanistically understand the regulation of microglial sex effects across the lifespan, which may open new avenues for sex informed prevention and treatment strategies.
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Affiliation(s)
- Sarah R Ocañas
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
| | - Victor A Ansere
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Collyn M Kellogg
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA; Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Jose V V Isola
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Ana J Chucair-Elliott
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Willard M Freeman
- Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA; Oklahoma City Veterans Affairs Medical Center, Oklahoma City, OK, USA; Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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Vanderhaeghen P, Polleux F. Developmental mechanisms underlying the evolution of human cortical circuits. Nat Rev Neurosci 2023; 24:213-232. [PMID: 36792753 PMCID: PMC10064077 DOI: 10.1038/s41583-023-00675-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2023] [Indexed: 02/17/2023]
Abstract
The brain of modern humans has evolved remarkable computational abilities that enable higher cognitive functions. These capacities are tightly linked to an increase in the size and connectivity of the cerebral cortex, which is thought to have resulted from evolutionary changes in the mechanisms of cortical development. Convergent progress in evolutionary genomics, developmental biology and neuroscience has recently enabled the identification of genomic changes that act as human-specific modifiers of cortical development. These modifiers influence most aspects of corticogenesis, from the timing and complexity of cortical neurogenesis to synaptogenesis and the assembly of cortical circuits. Mutations of human-specific genetic modifiers of corticogenesis have started to be linked to neurodevelopmental disorders, providing evidence for their physiological relevance and suggesting potential relationships between the evolution of the human brain and its sensitivity to specific diseases.
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Affiliation(s)
- Pierre Vanderhaeghen
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium.
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium.
| | - Franck Polleux
- Department of Neuroscience, Columbia University Medical Center, New York, NY, USA.
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
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Lupan BM, Solecki RA, Musso CM, Alsina FC, Silver DL. The exon junction complex component EIF4A3 is essential for mouse and human cortical progenitor mitosis and neurogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.13.524010. [PMID: 36711736 PMCID: PMC9882224 DOI: 10.1101/2023.01.13.524010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Mutations in components of the exon junction complex (EJC) are associated with neurodevelopment and disease. In particular, reduced levels of the RNA helicase EIF4A3 cause Richieri-Costa-Pereira Syndrome (RCPS) and CNVs are linked to intellectual disability. Consistent with this, Eif4a3 haploinsufficient mice are microcephalic. Altogether, this implicates EIF4A3 in cortical development; however, the underlying mechanisms are poorly understood. Here, we use mouse and human models to demonstrate that EIF4A3 promotes cortical development by controlling progenitor mitosis, cell fate, and survival. Eif4a3 haploinsufficiency in mice causes extensive cell death and impairs neurogenesis. Using Eif4a3 ; p53 compound mice, we show that apoptosis is most impactful for early neurogenesis, while additional p53-independent mechanisms contribute to later stages. Live imaging of mouse and human neural progenitors reveals Eif4a3 controls mitosis length, which influences progeny fate and viability. These phenotypes are conserved as cortical organoids derived from RCPS iPSCs exhibit aberrant neurogenesis. Finally, using rescue experiments we show that EIF4A3 controls neuron generation via the EJC. Altogether, our study demonstrates that EIF4A3 mediates neurogenesis by controlling mitosis duration and cell survival, implicating new mechanisms underlying EJC-mediated disorders. Summary statement This study shows that EIF4A3 mediates neurogenesis by controlling mitosis duration in both mouse and human neural progenitors, implicating new mechanisms underlying neurodevelopmental disorders.
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Ryan CS, Schröder M. The human DEAD-box helicase DDX3X as a regulator of mRNA translation. Front Cell Dev Biol 2022; 10:1033684. [PMID: 36393867 PMCID: PMC9642913 DOI: 10.3389/fcell.2022.1033684] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/07/2022] [Indexed: 08/27/2023] Open
Abstract
The human DEAD-box protein DDX3X is an RNA remodelling enzyme that has been implicated in various aspects of RNA metabolism. In addition, like many DEAD-box proteins, it has non-conventional functions that are independent of its enzymatic activity, e.g., DDX3X acts as an adaptor molecule in innate immune signalling pathways. DDX3X has been linked to several human diseases. For example, somatic mutations in DDX3X were identified in various human cancers, and de novo germline mutations cause a neurodevelopmental condition now termed 'DDX3X syndrome'. DDX3X is also an important host factor in many different viral infections, where it can have pro-or anti-viral effects depending on the specific virus. The regulation of translation initiation for specific mRNA transcripts is likely a central cellular function of DDX3X, yet many questions regarding its exact targets and mechanisms of action remain unanswered. In this review, we explore the current knowledge about DDX3X's physiological RNA targets and summarise its interactions with the translation machinery. A role for DDX3X in translational reprogramming during cellular stress is emerging, where it may be involved in the regulation of stress granule formation and in mediating non-canonical translation initiation. Finally, we also discuss the role of DDX3X-mediated translation regulation during viral infections. Dysregulation of DDX3X's function in mRNA translation likely contributes to its involvement in disease pathophysiology. Thus, a better understanding of its exact mechanisms for regulating translation of specific mRNA targets is important, so that we can potentially develop therapeutic strategies for overcoming the negative effects of its dysregulation.
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Cabrera Zapata LE, Garcia-Segura LM, Cambiasso MJ, Arevalo MA. Genetics and Epigenetics of the X and Y Chromosomes in the Sexual Differentiation of the Brain. Int J Mol Sci 2022; 23:ijms232012288. [PMID: 36293143 PMCID: PMC9603441 DOI: 10.3390/ijms232012288] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 11/27/2022] Open
Abstract
For many decades to date, neuroendocrinologists have delved into the key contribution of gonadal hormones to the generation of sex differences in the developing brain and the expression of sex-specific physiological and behavioral phenotypes in adulthood. However, it was not until recent years that the role of sex chromosomes in the matter started to be seriously explored and unveiled beyond gonadal determination. Now we know that the divergent evolutionary process suffered by X and Y chromosomes has determined that they now encode mostly dissimilar genetic information and are subject to different epigenetic regulations, characteristics that together contribute to generate sex differences between XX and XY cells/individuals from the zygote throughout life. Here we will review and discuss relevant data showing how particular X- and Y-linked genes and epigenetic mechanisms controlling their expression and inheritance are involved, along with or independently of gonadal hormones, in the generation of sex differences in the brain.
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Affiliation(s)
- Lucas E. Cabrera Zapata
- Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Córdoba, Córdoba 5016, Argentina
- Instituto Cajal (IC), Consejo Superior de Investigaciones Científicas (CSIC), 28002 Madrid, Spain
| | | | - María Julia Cambiasso
- Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Córdoba, Córdoba 5016, Argentina
- Cátedra de Biología Celular, Facultad de Odontología, Universidad Nacional de Córdoba, Córdoba 5000, Argentina
- Correspondence: (M.J.C.); (M.A.A.)
| | - Maria Angeles Arevalo
- Instituto Cajal (IC), Consejo Superior de Investigaciones Científicas (CSIC), 28002 Madrid, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence: (M.J.C.); (M.A.A.)
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Shohat S, Vol E, Shifman S. Gene essentiality in cancer cell lines is modified by the sex chromosomes. Genome Res 2022; 32:1993-2002. [PMID: 36418059 PMCID: PMC9808629 DOI: 10.1101/gr.276488.121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 11/16/2022] [Indexed: 11/27/2022]
Abstract
Human sex differences arise from gonadal hormones and sex chromosomes. Studying the direct effects of sex chromosomes in humans is still challenging. Here we studied how the sex chromosomes can modulate gene expression and the outcome of mutations across the genome by exploiting the tendency of cancer cell lines to lose or gain sex chromosomes. We inferred the dosage of the sex chromosomes in 355 female and 408 male cancer cell lines and used it to dissect the contributions of the Y and X Chromosomes to sex-biased gene expression. Furthermore, based on genome-wide CRISPR screens, we identified genes whose essentiality is different between male and female cells depending on the sex chromosomes. The most significant genes were X-linked genes compensated by Y-linked paralogs. Our sex-based analysis identifies genes that, when mutated, can affect male and female cells differently and reinforces the roles of the X and Y Chromosomes in sex-specific cell function.
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