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He R, Dong T, Chu J, Wang Y, Wang X, Song Y, Sun Y. Phaser-Trim: A Phase Separation Based Genetically Encoded Reporter for H3K9 Trimethylation in Living Cells. Anal Chem 2024. [PMID: 39101551 DOI: 10.1021/acs.analchem.4c00992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2024]
Abstract
Histone methylation is a key epigenetic modification that regulates the chromatin structure and gene expression for proper cellular and physiological processes. Aberrant histone methylation patterns are implicated in many diseases. Therefore, monitoring histone methylation dynamics in living cells and species is essential for elucidating its regulatory mechanisms and identifying potential therapeutic targets. However, current methods for detecting histone methylation are limited by their low sensitivity and specificity. To overcome this challenge, we have developed a genetically encoded biosensor named Phaser-Trim (Phase separation based genetically encoded reporter for H3K9 Trimethylation) to detect the dynamic changes of H3K9me3 in living cells and species through the generation and disappearance of phase-separated droplets. Phaser-Trim demonstrates advantages of clear phenotypic characteristics, convenient operation, quantitative accuracy, biocompatibility, high specificity, and superior imaging performance with high signal-to-background ratio (SBR) for in vivo animal imaging. Using Phaser-Trim, we have successfully detected the dynamics of the H3K9me3 level during the differentiation of neural stem cells in Drosophila. Furthermore, Phaser-Trim also holds promise for application in high-throughput screening systems to facilitate the discovery of novel anticancer drugs.
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Affiliation(s)
- Renxi He
- National Biomedical Imaging Center, College of Future Technology, State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871, China
| | - Tian Dong
- National Biomedical Imaging Center, College of Future Technology, State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871, China
| | - Jingyi Chu
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Yao Wang
- National Biomedical Imaging Center, College of Future Technology, State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871, China
| | - Xiaotian Wang
- National Biomedical Imaging Center, College of Future Technology, State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871, China
| | - Yan Song
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, 100871, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Yujie Sun
- National Biomedical Imaging Center, College of Future Technology, State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871, China
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2
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Khaket TP, Rimal S, Wang X, Bhurtel S, Wu YC, Lu B. Ribosome stalling during c-myc translation presents actionable cancer cell vulnerability. PNAS NEXUS 2024; 3:pgae321. [PMID: 39161732 PMCID: PMC11330866 DOI: 10.1093/pnasnexus/pgae321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Accepted: 07/14/2024] [Indexed: 08/21/2024]
Abstract
Myc is a major driver of tumor initiation, progression, and maintenance. Up-regulation of Myc protein level rather than acquisition of neomorphic properties appears to underlie most Myc-driven cancers. Cellular mechanisms governing Myc expression remain incompletely defined. In this study, we show that ribosome-associated quality control (RQC) plays a critical role in maintaining Myc protein level. Ribosomes stall during the synthesis of the N-terminal portion of cMyc, generating aberrant cMyc species and necessitating deployment of the early RQC factor ZNF598 to handle translational stress and restore cMyc translation. ZNF598 expression is up-regulated in human glioblastoma (GBM), and its expression positively correlates with that of cMyc. ZNF598 knockdown inhibits human GBM neurosphere formation in cell culture and Myc-dependent tumor growth in vivo in Drosophila. Intriguingly, the SARS-COV-2-encoded translational regulator Nsp1 impinges on ZNF598 to restrain cMyc translation and consequently cMyc-dependent cancer growth. Remarkably, Nsp1 exhibits synthetic toxicity with the translation and RQC-related factor ATP-binding cassette subfamily E member 1, which, despite its normally positive correlation with cMyc in cancer cells, is co-opted by Nsp1 to down-regulate cMyc and inhibit tumor growth. Ribosome stalling during c-myc translation thus offers actionable cancer cell vulnerability.
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Affiliation(s)
- Tejinder Pal Khaket
- Department of Pathology and Programs in Neuroscience and Cancer Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Suman Rimal
- Department of Pathology and Programs in Neuroscience and Cancer Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Xingjun Wang
- Department of Pathology and Programs in Neuroscience and Cancer Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sunil Bhurtel
- Department of Pathology and Programs in Neuroscience and Cancer Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yen-Chi Wu
- Department of Pathology and Programs in Neuroscience and Cancer Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Bingwei Lu
- Department of Pathology and Programs in Neuroscience and Cancer Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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3
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Li Y, Liu D, Wang H, Zhang X, Lu B, Li S. The IRE1/Xbp1 axis restores ER and tissue homeostasis perturbed by excess Notch in Drosophila. Dev Biol 2024; 507:11-19. [PMID: 38142805 DOI: 10.1016/j.ydbio.2023.12.007] [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: 08/28/2023] [Revised: 12/15/2023] [Accepted: 12/17/2023] [Indexed: 12/26/2023]
Abstract
Notch signaling controls numerous key cellular processes including cell fate determination and cell proliferation. Its malfunction has been linked to many developmental abnormalities and human disorders. Overactivation of Notch signaling is shown to be oncogenic. Retention of excess Notch protein in the endoplasmic reticulum (ER) can lead to altered Notch signaling and cell fate, but the mechanism is not well understood. In this study, we show that V5-tagged or untagged exogenous Notch is retained in the ER when overexpressed in fly tissues. Furthermore, we show that Notch retention in the ER leads to robust ER enlargement and elicits a rough eye phenotype. Gain-of-function of unfolded protein response (UPR) factors IRE1 or spliced Xbp1 (Xbp1-s) alleviates Notch accumulation in the ER, restores ER morphology and ameliorates the rough eye phenotype. Our results uncover a pivotal role of the IRE1/Xbp1 axis in regulating the detrimental effect of ER-localized excess Notch protein during development and tissue homeostasis.
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Affiliation(s)
- Yu Li
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Dongyue Liu
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Haochuan Wang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Xuejing Zhang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Bingwei Lu
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Shuangxi Li
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China.
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4
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Zhang H, Rui M, Ma Z, Gong S, Zhang S, Zhou Q, Gan C, Gong W, Wang S. Golgi-to-ER retrograde transport prevents premature differentiation of Drosophila type II neuroblasts via Notch-signal-sending daughter cells. iScience 2024; 27:108545. [PMID: 38213621 PMCID: PMC10783626 DOI: 10.1016/j.isci.2023.108545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 09/18/2023] [Accepted: 11/20/2023] [Indexed: 01/13/2024] Open
Abstract
Stem cells are heterogeneous to generate diverse differentiated cell types required for organogenesis; however, the underlying mechanisms that differently maintain these heterogeneous stem cells are not well understood. In this study, we identify that Golgi-to-endoplasmic reticulum (ER) retrograde transport specifically maintains type II neuroblasts (NBs) through the Notch signaling. We reveal that intermediate neural progenitors (INPs), immediate daughter cells of type II NBs, provide Delta and function as the NB niche. The Delta used by INPs is mainly produced by NBs and asymmetrically distributed to INPs. Blocking retrograde transport leads to a decrease in INP number, which reduces Notch activity and results in the premature differentiation of type II NBs. Furthermore, the reduction of Delta could suppress tumor formation caused by type II NBs. Our results highlight the crosstalk between Golgi-to-ER retrograde transport, Notch signaling, stem cell niche, and fusion as an essential step in maintaining the self-renewal of type II NB lineage.
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Affiliation(s)
- Huanhuan Zhang
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Menglong Rui
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Zhixin Ma
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Sifan Gong
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Shuliu Zhang
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Qingxia Zhou
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Congfeng Gan
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Wenting Gong
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Su Wang
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226019, China
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5
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Diaz LR, Gil-Ranedo J, Jaworek KJ, Nsek N, Marques JP, Costa E, Hilton DA, Bieluczyk H, Warrington O, Hanemann CO, Futschik ME, Bossing T, Barros CS. Ribogenesis boosts controlled by HEATR1-MYC interplay promote transition into brain tumour growth. EMBO Rep 2024; 25:168-197. [PMID: 38225354 PMCID: PMC10897169 DOI: 10.1038/s44319-023-00017-1] [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: 02/06/2023] [Revised: 11/16/2023] [Accepted: 11/22/2023] [Indexed: 01/17/2024] Open
Abstract
Cell commitment to tumourigenesis and the onset of uncontrolled growth are critical determinants in cancer development but the early events directing tumour initiating cell (TIC) fate remain unclear. We reveal a single-cell transcriptome profile of brain TICs transitioning into tumour growth using the brain tumour (brat) neural stem cell-based Drosophila model. Prominent changes in metabolic and proteostasis-associated processes including ribogenesis are identified. Increased ribogenesis is a known cell adaptation in established tumours. Here we propose that brain TICs boost ribogenesis prior to tumour growth. In brat-deficient TICs, we show that this dramatic change is mediated by upregulated HEAT-Repeat Containing 1 (HEATR1) to promote ribosomal RNA generation, TIC enlargement and onset of overgrowth. High HEATR1 expression correlates with poor glioma patient survival and patient-derived glioblastoma stem cells rely on HEATR1 for enhanced ribogenesis and tumourigenic potential. Finally, we show that HEATR1 binds the master growth regulator MYC, promotes its nucleolar localisation and appears required for MYC-driven ribogenesis, suggesting a mechanism co-opted in ribogenesis reprogramming during early brain TIC development.
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Affiliation(s)
- Laura R Diaz
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Jon Gil-Ranedo
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Karolina J Jaworek
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
- School of Biological Sciences, Bangor University, LL57 2UW, Bangor, UK
| | - Nsikan Nsek
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Joao Pinheiro Marques
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Eleni Costa
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - David A Hilton
- Department of Cellular and Anatomical Pathology, University Hospitals Plymouth, PL6 8DH, Plymouth, UK
| | - Hubert Bieluczyk
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Oliver Warrington
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, WC1N 3AR, London, UK
| | - C Oliver Hanemann
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Matthias E Futschik
- School of Biomedical Sciences, Faculty of Health, Derriford Research Facility, University of Plymouth, PL6 8BU, Plymouth, UK
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3004-504, Coimbra, Portugal
| | - Torsten Bossing
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Claudia S Barros
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK.
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6
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Chavda V, Lu B. Reverse Electron Transport at Mitochondrial Complex I in Ischemic Stroke, Aging, and Age-Related Diseases. Antioxidants (Basel) 2023; 12:antiox12040895. [PMID: 37107270 PMCID: PMC10135819 DOI: 10.3390/antiox12040895] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 03/28/2023] [Accepted: 03/31/2023] [Indexed: 04/09/2023] Open
Abstract
Stroke is one of the leading causes of morbidity and mortality worldwide. A main cause of brain damage by stroke is ischemia-reperfusion (IR) injury due to the increased production of reactive oxygen species (ROS) and energy failure caused by changes in mitochondrial metabolism. Ischemia causes a build-up of succinate in tissues and changes in the mitochondrial NADH: ubiquinone oxidoreductase (complex I) activity that promote reverse electron transfer (RET), in which a portion of the electrons derived from succinate are redirected from ubiquinol along complex I to reach the NADH dehydrogenase module of complex I, where matrix NAD+ is converted to NADH and excessive ROS is produced. RET has been shown to play a role in macrophage activation in response to bacterial infection, electron transport chain reorganization in response to changes in the energy supply, and carotid body adaptation to changes in the oxygen levels. In addition to stroke, deregulated RET and RET-generated ROS (RET-ROS) have been implicated in tissue damage during organ transplantation, whereas an RET-induced NAD+/NADH ratio decrease has been implicated in aging, age-related neurodegeneration, and cancer. In this review, we provide a historical account of the roles of ROS and oxidative damage in the pathogenesis of ischemic stroke, summarize the latest developments in our understanding of RET biology and RET-associated pathological conditions, and discuss new ways to target ischemic stroke, cancer, aging, and age-related neurodegenerative diseases by modulating RET.
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Affiliation(s)
- Vishal Chavda
- Department of Pathology, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Bingwei Lu
- Department of Pathology, School of Medicine, Stanford University, Stanford, CA 94305, USA
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7
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Rebelo AR, Homem CCF. dMyc-dependent upregulation of CD98 amino acid transporters is required for Drosophila brain tumor growth. Cell Mol Life Sci 2023; 80:30. [PMID: 36609617 PMCID: PMC9823048 DOI: 10.1007/s00018-022-04668-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 11/30/2022] [Accepted: 12/11/2022] [Indexed: 01/07/2023]
Abstract
Tumor cells have an increased demand for nutrients to sustain their growth, but how these increased metabolic needs are ensured or how this influences tumor formation and progression remains unclear. To unravel tumor metabolic dependencies, particularly from extracellular metabolites, we have analyzed the role of plasma membrane metabolic transporters in Drosophila brain tumors. Using a well-established neural stem cell-derived tumor model, caused by brat knockdown, we have found that 13 plasma membrane metabolic transporters, including amino acid, carbohydrate and monocarboxylate transporters, are upregulated in tumors and are required for tumor growth. We identified CD98hc and several of the light chains with which it can form heterodimeric amino acid transporters, as crucial players in brat RNAi (brat IR) tumor progression. Knockdown of these components of CD98 heterodimers caused a dramatic reduction in tumor growth. Our data also reveal that the oncogene dMyc is required and sufficient for the upregulation of CD98 transporter subunits in these tumors. Furthermore, tumor-upregulated dmyc and CD98 transporters orchestrate the overactivation of the growth-promoting signaling pathway TOR, forming a core growth regulatory network to support brat IR tumor progression. Our findings highlight the important link between oncogenes, metabolism, and signaling pathways in the regulation of tumor growth and allow for a better understanding of the mechanisms necessary for tumor progression.
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Affiliation(s)
- Ana R Rebelo
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Catarina C F Homem
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade Nova de Lisboa, Lisbon, Portugal.
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8
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Egger B. Neural Stem Cells and Brain Tumour Models in Drosophila. Neurogenetics 2023. [DOI: 10.1007/978-3-031-07793-7_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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9
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Aquila G, Alaimo A, Marracino L, Martino V, Camponogara F, Vieceli Dalla Sega F, Fortini F, Pannuti A, Zanotti C, Malagutti N, Pelucchi S, Rizzo P. Characterization of the Notch pathway in nasal polyps of patients with chronic rhinosinusitis: A pilot study. Physiol Rep 2022; 10:e15403. [PMID: 36029197 PMCID: PMC9419157 DOI: 10.14814/phy2.15403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/08/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023] Open
Abstract
Chronic rhinosinusitis with nasal polyps is a widespread pathology characterized by persistent inflammation of nasal and paranasal mucosa. Although it represents one of the most frequent diseases of the nasal cavities, its etiology is still not completely elucidated. There is evidence suggesting that the Notch signaling, a highly conserved intercellular pathway known to regulate many cellular processes, including inflammation, is implicated in nasal polyps formation. The purpose of this study was to investigate the expression of genes of the Notch pathway in nasal polyps from patients with chronic rhinosinusitis. Nasal polyps and adjacent mucosa tissue were obtained from 10 patients. RNA was analyzed by quantitative reverse transcriptase-polymerase chain reaction for the expression level of (1) Notch pathway components such as receptors (NOTCH1-4), ligands (DLL4, JAGGED-1), and target genes (HEY1, 2, and HES1) and (2) genes providing information on the pathogenesis of polyposis (C-MYC and SCGB1A1) and on eosinophils content (CCL26, IL5, and SAA2). We report a Notch-driven gene expression pattern in nasal polyps which correlates with the expression of genes highly expressed in eosinophils, whose presence is an important parameter to define the pathophysiologic diversity characterizing nasal polyps. Taken together, our results suggest a role for Notch signaling in the pathophysiology of polyposis. Further studies are needed to elucidate the role of Notch in nasal polyps formation and to establish whether it could represent a novel therapeutic target for this pathology.
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Affiliation(s)
- Giorgio Aquila
- Department of Medical SciencesUniversity of FerraraFerraraItaly
| | - Alessandra Alaimo
- Department of Ear, Nose and ThroatUniversity Hospital of FerraraFerraraItaly
| | - Luisa Marracino
- Department of Translational Medicine and Laboratory for Technologies of Advanced Therapies (LTTA)University of FerraraFerraraItaly
| | - Valeria Martino
- Department of Medical SciencesUniversity of FerraraFerraraItaly
| | - Francesca Camponogara
- Department of Translational Medicine and Laboratory for Technologies of Advanced Therapies (LTTA)University of FerraraFerraraItaly
| | - Francesco Vieceli Dalla Sega
- Department of Translational Medicine and Laboratory for Technologies of Advanced Therapies (LTTA)University of FerraraFerraraItaly
| | - Francesca Fortini
- Department of Translational Medicine and Laboratory for Technologies of Advanced Therapies (LTTA)University of FerraraFerraraItaly
| | - Antonio Pannuti
- University of Hawaii Cancer Center, University of HawaiiHonoluluHawaiiUSA
| | - Claudia Zanotti
- Department of Neuroscience DNS, Section of OtolaryngologyUniversity of PadovaPadovaItaly
| | - Nicola Malagutti
- Department of Ear, Nose and ThroatUniversity Hospital of FerraraFerraraItaly
| | - Stefano Pelucchi
- Department of Ear, Nose and ThroatUniversity Hospital of FerraraFerraraItaly
| | - Paola Rizzo
- Department of Translational Medicine and Laboratory for Technologies of Advanced Therapies (LTTA)University of FerraraFerraraItaly
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10
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Ojha R, Tantray I, Rimal S, Mitra S, Cheshier S, Lu B. Regulation of reverse electron transfer at mitochondrial complex I by unconventional Notch action in cancer stem cells. Dev Cell 2022; 57:260-276.e9. [PMID: 35077680 PMCID: PMC8852348 DOI: 10.1016/j.devcel.2021.12.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 10/06/2021] [Accepted: 12/21/2021] [Indexed: 01/26/2023]
Abstract
Metabolic flexibility is a hallmark of many cancers where mitochondrial respiration is critically involved, but the molecular underpinning of mitochondrial control of cancer metabolic reprogramming is poorly understood. Here, we show that reverse electron transfer (RET) through respiratory chain complex I (RC-I) is particularly active in brain cancer stem cells (CSCs). Although RET generates ROS, NAD+/NADH ratio turns out to be key in mediating RET effect on CSC proliferation, in part through the NAD+-dependent Sirtuin. Mechanistically, Notch acts in an unconventional manner to regulate RET by interacting with specific RC-I proteins containing electron-transporting Fe-S clusters and NAD(H)-binding sites. Genetic and pharmacological interference of Notch-mediated RET inhibited CSC growth in Drosophila brain tumor and mouse glioblastoma multiforme (GBM) models. Our results identify Notch as a regulator of RET and RET-induced NAD+/NADH balance, a critical mechanism of metabolic reprogramming and a metabolic vulnerability of cancer that may be exploited for therapeutic purposes.
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Affiliation(s)
- Rani Ojha
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA,These authors contributed equally
| | - Ishaq Tantray
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA,These authors contributed equally
| | - Suman Rimal
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Siddhartha Mitra
- Stem Cell Institute and Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA,Department of Pediatrics, Division of Hematology/Oncology/Bone Marrow Transplant, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Sam Cheshier
- Stem Cell Institute and Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA,Department of Neurosurgery, Division of Pediatric Neurosurgery, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Bingwei Lu
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA,Cancer Biology Program, Stanford University School of Medicine, Stanford, CA, USA,Lead Contact,Correspondence:
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11
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Rajan A, Ostgaard CM, Lee CY. Regulation of Neural Stem Cell Competency and Commitment during Indirect Neurogenesis. Int J Mol Sci 2021; 22:12871. [PMID: 34884676 PMCID: PMC8657492 DOI: 10.3390/ijms222312871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/24/2021] [Accepted: 11/24/2021] [Indexed: 11/29/2022] Open
Abstract
Indirect neurogenesis, during which neural stem cells generate neurons through intermediate progenitors, drives the evolution of lissencephalic brains to gyrencephalic brains. The mechanisms that specify intermediate progenitor identity and that regulate stem cell competency to generate intermediate progenitors remain poorly understood despite their roles in indirect neurogenesis. Well-characterized lineage hierarchy and available powerful genetic tools for manipulating gene functions make fruit fly neural stem cell (neuroblast) lineages an excellent in vivo paradigm for investigating the mechanisms that regulate neurogenesis. Type II neuroblasts in fly larval brains repeatedly undergo asymmetric divisions to generate intermediate neural progenitors (INPs) that undergo limited proliferation to increase the number of neurons generated per stem cell division. Here, we review key regulatory genes and the mechanisms by which they promote the specification and generation of INPs, safeguarding the indirect generation of neurons during fly larval brain neurogenesis. Homologs of these regulators of INPs have been shown to play important roles in regulating brain development in vertebrates. Insight into the precise regulation of intermediate progenitors will likely improve our understanding of the control of indirect neurogenesis during brain development and brain evolution.
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Affiliation(s)
- Arjun Rajan
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (A.R.); (C.M.O.)
| | - Cyrina M. Ostgaard
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (A.R.); (C.M.O.)
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Cheng-Yu Lee
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (A.R.); (C.M.O.)
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Division of Genetic Medicine, Department of Internal Medicine and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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12
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Gong S, Zhang Y, Tian A, Deng W. Tumor models in various Drosophila tissues. WIREs Mech Dis 2021; 13:e1525. [PMID: 34730289 PMCID: PMC8566734 DOI: 10.1002/wsbm.1525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 01/07/2023]
Abstract
The development of cancer is a complex multistage process. Over the past few decades, the model organism Drosophila melanogaster has been crucial in identifying cancer-related genes and pathways and elucidating mechanisms underlying growth regulation in development. Investigations using Drosophila has yielded new insights into the molecular mechanisms involved in tumor initiation and progression. In this review, we describe various tumor models that have been developed in recent years using different Drosophila tissues, such as the imaginal tissue, the neural tissue, the gut, the ovary, and hematopoietic cells. We discuss underlying genetic alterations, cancer-like characteristics, as well as similarities and key differences among these models. We also discuss how disruptions in stem cell division and differentiation result in tumor formation in diverse tissues, and highlight new concepts developed using the fly model to understand context-dependent tumorigenesis. We further discuss the progress made in Drosophila to explore tumor-host interactions that involve the innate immune response to tumor growth and the cachexia wasting phenotype. This article is categorized under: Cancer > Genetics/Genomics/Epigenetics Cancer > Stem Cells and Development Cancer > Molecular and Cellular Physiology.
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Affiliation(s)
- Shangyu Gong
- Department of Biochemistry and Molecular BiologyTulane University School of MedicineNew OrleansLouisianaUSA
| | - Yichi Zhang
- Department of Biochemistry and Molecular BiologyTulane University School of MedicineNew OrleansLouisianaUSA
| | - Aiguo Tian
- Department of Biochemistry and Molecular BiologyTulane University School of MedicineNew OrleansLouisianaUSA
| | - Wu‐Min Deng
- Department of Biochemistry and Molecular BiologyTulane University School of MedicineNew OrleansLouisianaUSA
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13
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Chen R, Hou Y, Connell M, Zhu S. Homeodomain protein Six4 prevents the generation of supernumerary Drosophila type II neuroblasts and premature differentiation of intermediate neural progenitors. PLoS Genet 2021; 17:e1009371. [PMID: 33556050 PMCID: PMC7895384 DOI: 10.1371/journal.pgen.1009371] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 02/19/2021] [Accepted: 01/15/2021] [Indexed: 11/19/2022] Open
Abstract
In order to boost the number and diversity of neurons generated from neural stem cells, intermediate neural progenitors (INPs) need to maintain their homeostasis by avoiding both dedifferentiation and premature differentiation. Elucidating how INPs maintain homeostasis is critical for understanding the generation of brain complexity and various neurological diseases resulting from defects in INP development. Here we report that Six4 expressed in Drosophila type II neuroblast (NB) lineages prevents the generation of supernumerary type II NBs and premature differentiation of INPs. We show that loss of Six4 leads to supernumerary type II NBs likely due to dedifferentiation of immature INPs (imINPs). We provide data to further demonstrate that Six4 inhibits the expression and activity of PntP1 in imINPs in part by forming a trimeric complex with Earmuff and PntP1. Furthermore, knockdown of Six4 exacerbates the loss of INPs resulting from the loss of PntP1 by enhancing ectopic Prospero expression in imINPs, suggesting that Six4 is also required for preventing premature differentiation of INPs. Taken together, our work identified a novel transcription factor that likely plays important roles in maintaining INP homeostasis. Intermediate neural progenitors (INPs) are descendants of neural stem cells that can proliferate for a short term to amplify the number of nerve cells generated in the brain. INPs play critical roles in determining how big and complex a brain can grow. To perform their function, INPs need to maintain their own population and must not adopt the identity of neural stem cells, a process called dedifferentiation, or acquire the fate of their own daughter cells and stop proliferation too soon, a process called premature differentiation. However, how INPs avoid dedifferentiation and premature differentiation is not fully understood. In this study, we identified a protein called Six4 as a novel factor that plays important roles in preventing the generation of extra neural stem cells and premature differentiation of INPs in developing fruit fly brains. We described how Six4 functionally and physically interacts with other factors that are involved in regulating INP cell fate specification. Our work provides novel insights into the mechanisms regulating INP development and could have important implications in understanding how complex brains are generated during normal development and how abnormal brain development or brain tumor can occur when INPs fail to avoid premature differentiation or dedifferentiation.
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Affiliation(s)
- Rui Chen
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, United States of America
| | - Yanjun Hou
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, United States of America
| | - Marisa Connell
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, United States of America
| | - Sijun Zhu
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, United States of America
- * E-mail:
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14
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MYC in Brain Development and Cancer. Int J Mol Sci 2020; 21:ijms21207742. [PMID: 33092025 PMCID: PMC7588885 DOI: 10.3390/ijms21207742] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 10/16/2020] [Accepted: 10/16/2020] [Indexed: 12/27/2022] Open
Abstract
The MYC family of transcriptional regulators play significant roles in animal development, including the renewal and maintenance of stem cells. Not surprisingly, given MYC's capacity to promote programs of proliferative cell growth, MYC is frequently upregulated in cancer. Although members of the MYC family are upregulated in nervous system tumours, the mechanisms of how elevated MYC promotes stem cell-driven brain cancers is unknown. If we are to determine how increased MYC might contribute to brain cancer progression, we will require a more complete understanding of MYC's roles during normal brain development. Here, we evaluate evidence for MYC family functions in neural stem cell fate and brain development, with a view to better understand mechanisms of MYC-driven neural malignancies.
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15
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Connacher RP, Goldstrohm AC. Molecular and biological functions of TRIM-NHL RNA-binding proteins. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1620. [PMID: 32738036 DOI: 10.1002/wrna.1620] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/17/2020] [Accepted: 06/19/2020] [Indexed: 01/02/2023]
Abstract
The TRIM-NHL family of proteins shares a conserved domain architecture and play crucial roles in stem cell biology, fertility, and development. This review synthesizes new insights that have revolutionized our understanding of the molecular and biological functions of TRIM-NHL proteins. Multiple TRIM-NHLs have been shown to bind specific RNA sequences and structures. X-ray crystal structures of TRIM-NHL proteins in complex with RNA ligands reveal versatile modes of RNA recognition by the NHL domain. Functional and genetic analyses show that TRIM-NHL RNA-binding proteins negatively regulate the protein expression from the target mRNAs that they bind. This repressive activity plays a crucial role in controlling stem cell fate in the developing brain and differentiating germline. To highlight these paradigms, we focus on several of the most-extensively studied TRIM-NHL proteins, specifically Drosophila and vertebrate TRIM71, among others. Brat is essential for development and regulates key target mRNAs to control differentiation of germline and neural stem cells. TRIM71 is also required for development and promotes stem cell proliferation while antagonizing differentiation. Moreover, TRIM71 can be utilized to help reprogram fibroblasts into induced pluripotent stem cells. Recently discovered mutations in TRIM71 cause the neurodevelopmental disease congenital hydrocephalus and emphasize the importance of its RNA-binding function in brain development. Further relevance of TRIM71 to disease pathogenesis comes from evidence linking it to several types of cancer, including liver and testicular cancer. Collectively, these advances demonstrate a primary role for TRIM-NHL proteins in the post-transcriptional regulation of gene expression in crucial biological processes. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Translation > Translation Regulation RNA Turnover and Surveillance > Regulation of RNA Stability.
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Affiliation(s)
- Robert P Connacher
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
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16
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The Integrator Complex Prevents Dedifferentiation of Intermediate Neural Progenitors back into Neural Stem Cells. Cell Rep 2020; 27:987-996.e3. [PMID: 31018143 DOI: 10.1016/j.celrep.2019.03.089] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 01/31/2019] [Accepted: 03/24/2019] [Indexed: 01/08/2023] Open
Abstract
Mutations of the Integrator subunits are associated with neurodevelopmental disorders and cancers. However, their role during neural development is poorly understood. Here, we demonstrate that the Drosophila Integrator complex prevents dedifferentiation of intermediate neural progenitors (INPs) during neural stem cell (neuroblast) lineage development. Loss of intS5, intS8, and intS1 generated ectopic type II neuroblasts. INP-specific knockdown of intS8, intS1, and intS2 resulted in the formation of excess type II neuroblasts, indicating that Integrator prevents INP dedifferentiation. Cell-type-specific DamID analysis identified 1413 IntS5-binding sites in INPs, including zinc-finger transcription factor earmuff (erm). Furthermore, erm expression is lost in intS5 and intS8 mutant neuroblast lineages, and intS8 genetically interacts with erm to suppress the formation of ectopic neuroblasts. Taken together, our data demonstrate that the Drosophila Integrator complex plays a critical role in preventing INP dedifferentiation primarily by regulating a key transcription factor Erm that also suppresses INP dedifferentiation.
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17
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Liu X, Shen J, Xie L, Wei Z, Wong C, Li Y, Zheng X, Li P, Song Y. Mitotic Implantation of the Transcription Factor Prospero via Phase Separation Drives Terminal Neuronal Differentiation. Dev Cell 2020; 52:277-293.e8. [DOI: 10.1016/j.devcel.2019.11.019] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 10/09/2019] [Accepted: 11/26/2019] [Indexed: 11/26/2022]
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18
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Abdusselamoglu MD, Landskron L, Bowman SK, Eroglu E, Burkard T, Kingston RE, Knoblich JA. Dynamics of activating and repressive histone modifications in Drosophila neural stem cell lineages and brain tumors. Development 2019; 146:dev.183400. [PMID: 31748204 DOI: 10.1242/dev.183400] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/12/2019] [Indexed: 12/21/2022]
Abstract
During central nervous system development, spatiotemporal gene expression programs mediate specific lineage decisions to generate neuronal and glial cell types from neural stem cells (NSCs). However, little is known about the epigenetic landscape underlying these highly complex developmental events. Here, we perform ChIP-seq on distinct subtypes of Drosophila FACS-purified NSCs and their differentiated progeny to dissect the epigenetic changes accompanying the major lineage decisions in vivo By analyzing active and repressive histone modifications, we show that stem cell identity genes are silenced during differentiation by loss of their activating marks and not via repressive histone modifications. Our analysis also uncovers a new set of genes specifically required for altering lineage patterns in type II neuroblasts (NBs), one of the two main Drosophila NSC identities. Finally, we demonstrate that this subtype specification in NBs, unlike NSC differentiation, requires Polycomb-group-mediated repression.
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Affiliation(s)
- Merve Deniz Abdusselamoglu
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Lisa Landskron
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Sarah K Bowman
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Elif Eroglu
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Thomas Burkard
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Robert E Kingston
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Jürgen A Knoblich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
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19
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Piggott BJ, Peters CJ, He Y, Huang X, Younger S, Jan LY, Jan YN. Paralytic, the Drosophila voltage-gated sodium channel, regulates proliferation of neural progenitors. Genes Dev 2019; 33:1739-1750. [PMID: 31753914 PMCID: PMC6942049 DOI: 10.1101/gad.330597.119] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 10/28/2019] [Indexed: 12/23/2022]
Abstract
In this study, Piggott et al. set out to examine the role of paralytic, the sole voltage-gated sodium channel in Drosophila, in neural progenitors. Using cell biology assays and electrophysiological analysis, the authors report for the first time a developmental role of voltage-gated sodium channels in regulating neural progenitor proliferation in Drosophila larvae. Proliferating cells, typically considered “nonexcitable,” nevertheless, exhibit regulation by bioelectric signals. Notably, voltage-gated sodium channels (VGSC) that are crucial for neuronal excitability are also found in progenitors and up-regulated in cancer. Here, we identify a role for VGSC in proliferation of Drosophila neuroblast (NB) lineages within the central nervous system. Loss of paralytic (para), the sole gene that encodes Drosophila VGSC, reduces neuroblast progeny cell number. The type II neuroblast lineages, featuring a population of transit-amplifying intermediate neural progenitors (INP) similar to that found in the developing human cortex, are particularly sensitive to para manipulation. Following a series of asymmetric divisions, INPs normally exit the cell cycle through a final symmetric division. Our data suggests that loss of Para induces apoptosis in this population, whereas overexpression leads to an increase in INPs and overall neuroblast progeny cell numbers. These effects are cell autonomous and depend on Para channel activity. Reduction of Para expression not only affects normal NB development, but also strongly suppresses brain tumor mass, implicating a role for Para in cancer progression. To our knowledge, our studies are the first to identify a role for VGSC in neural progenitor proliferation. Elucidating the contribution of VGSC in proliferation will advance our understanding of bioelectric signaling within development and disease states.
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Affiliation(s)
- Beverly J Piggott
- Department of Physiology, Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94158, USA.,Howard Hughes Medical Institute
| | - Christian J Peters
- Department of Physiology, Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94158, USA
| | - Ye He
- Neuroscience Initiative, Advanced Science Research Center, the Graduate Center, City University of New York, New York 10031, New York
| | - Xi Huang
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada.,Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 3E1, Canada
| | - Susan Younger
- Department of Physiology, Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94158, USA.,Howard Hughes Medical Institute
| | - Lily Yeh Jan
- Department of Physiology, Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94158, USA.,Howard Hughes Medical Institute
| | - Yuh Nung Jan
- Department of Physiology, Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94158, USA.,Howard Hughes Medical Institute
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20
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Sander M, Herranz H. MicroRNAs in Drosophila Cancer Models. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1167:157-173. [PMID: 31520354 DOI: 10.1007/978-3-030-23629-8_9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
MiRNAs are post-transcriptional regulators of gene expression which have been implicated in virtually all biological processes. MiRNAs are frequently dysregulated in human cancers. However, the functional consequences of aberrant miRNA levels are not well understood. Drosophila is emerging as an important in vivo tumor model, especially in the identification of novel cancer genes. Here, we review Drosophila studies which functionally dissect the roles of miRNAs in tumorigenesis. Ultimately, these advances help to understand the implications of miRNA dysregulation in human cancers.
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Affiliation(s)
- Moritz Sander
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Héctor Herranz
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.
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21
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Mirzoyan Z, Sollazzo M, Allocca M, Valenza AM, Grifoni D, Bellosta P. Drosophila melanogaster: A Model Organism to Study Cancer. Front Genet 2019; 10:51. [PMID: 30881374 PMCID: PMC6405444 DOI: 10.3389/fgene.2019.00051] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 01/21/2019] [Indexed: 12/26/2022] Open
Abstract
Cancer is a multistep disease driven by the activation of specific oncogenic pathways concomitantly with the loss of function of tumor suppressor genes that act as sentinels to control physiological growth. The conservation of most of these signaling pathways in Drosophila, and the ability to easily manipulate them genetically, has made the fruit fly a useful model organism to study cancer biology. In this review we outline the basic mechanisms and signaling pathways conserved between humans and flies responsible of inducing uncontrolled growth and cancer development. Second, we describe classic and novel Drosophila models used to study different cancers, with the objective to discuss their strengths and limitations on their use to identify signals driving growth cell autonomously and within organs, drug discovery and for therapeutic approaches.
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Affiliation(s)
- Zhasmine Mirzoyan
- Department of Cellular, Computational and Integrative Biology, University of Trento, Trento, Italy
| | - Manuela Sollazzo
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Mariateresa Allocca
- Department of Cellular, Computational and Integrative Biology, University of Trento, Trento, Italy
| | | | - Daniela Grifoni
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Paola Bellosta
- Department of Cellular, Computational and Integrative Biology, University of Trento, Trento, Italy.,Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy.,Department of Biosciences, University of Milan, Milan, Italy.,Department of Medicine, NYU Langone Medical Center, New York, NY, United States
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22
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Liu K, Xu K, Song Y. Faster, higher, stronger: timely and robust cell fate/identity commitment in stem cell lineages. Open Biol 2019; 9:180243. [PMID: 30958098 PMCID: PMC6395883 DOI: 10.1098/rsob.180243] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Precise specification of cell fate or identity within stem cell lineages is critical for ensuring correct stem cell lineage progression and tissue homeostasis. Failure to specify cell fate or identity in a timely and robust manner can result in developmental abnormalities and diseases such as cancer. However, the molecular basis of timely cell fate/identity specification is only beginning to be understood. In this review, we discuss key regulatory strategies employed in cell fate specification and highlight recent results revealing how timely and robust cell fate/identity commitment is achieved through transcriptional control.
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Affiliation(s)
- Kun Liu
- 1 Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences , Beijing 100871 , People's Republic of China.,2 Peking-Tsinghua Center for Life Sciences, Peking University , Beijing 100871 , People's Republic of China
| | - Ke Xu
- 1 Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences , Beijing 100871 , People's Republic of China
| | - Yan Song
- 1 Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences , Beijing 100871 , People's Republic of China.,2 Peking-Tsinghua Center for Life Sciences, Peking University , Beijing 100871 , People's Republic of China
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23
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Froldi F, Pachnis P, Szuperák M, Costas O, Fernando T, Gould AP, Cheng LY. Histidine is selectively required for the growth of Myc-dependent dedifferentiation tumours in the Drosophila CNS. EMBO J 2019; 38:embj.201899895. [PMID: 30804004 PMCID: PMC6443203 DOI: 10.15252/embj.201899895] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 01/09/2019] [Accepted: 01/16/2019] [Indexed: 12/31/2022] Open
Abstract
Rewired metabolism of glutamine in cancer has been well documented, but less is known about other amino acids such as histidine. Here, we use Drosophila cancer models to show that decreasing the concentration of histidine in the diet strongly inhibits the growth of mutant clones induced by loss of Nerfin‐1 or gain of Notch activity. In contrast, changes in dietary histidine have much less effect on the growth of wildtype neural stem cells and Prospero neural tumours. The reliance of tumours on dietary histidine and also on histidine decarboxylase (Hdc) depends upon their growth requirement for Myc. We demonstrate that Myc overexpression in nerfin‐1 tumours is sufficient to switch their mode of growth from histidine/Hdc sensitive to resistant. This study suggests that perturbations in histidine metabolism selectively target neural tumours that grow via a dedifferentiation process involving large cell size increases driven by Myc.
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Affiliation(s)
- Francesca Froldi
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia
| | | | - Milán Szuperák
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Olivia Costas
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia
| | | | | | - Louise Y Cheng
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia .,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia.,The Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Vic., Australia
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24
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Read RD. Pvr receptor tyrosine kinase signaling promotes post-embryonic morphogenesis, and survival of glia and neural progenitor cells in Drosophila. Development 2018; 145:dev.164285. [PMID: 30327326 DOI: 10.1242/dev.164285] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 10/10/2018] [Indexed: 12/30/2022]
Abstract
Stem cells reside in specialized microenvironments, called niches, that regulate their development and the development of their progeny. However, the development and maintenance of niches are poorly understood. In the Drosophila brain, cortex glial cells provide a niche that promotes self-renewal and proliferation of neural stem cell-like cells (neuroblasts). In the central brain, neuroblasts and their progeny control post-embryonic morphogenesis of cortex glia through PDGF-like ligands, and this PDGFR receptor tyrosine kinase (RTK) signaling in cortex glia is required for expression of DE-cadherin, which sustains neuroblasts. Thus, through an RTK-dependent feed-forward loop, neuroblasts and their glial niche actively maintain each other. When the EGFR RTK is constitutively activated in cortex glia, they overexpress PDGF orthologs to stimulate autocrine PDGFR signaling, which uncouples their growth and survival from neuroblasts, and drives neoplastic glial transformation and elimination of neuroblasts. These results provide fundamental insights into glial development and niche regulation, and show that niche-neural stem cell feed-forward signaling becomes hijacked to drive neural tumorigenesis.
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Affiliation(s)
- Renee D Read
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
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25
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Li B, Wong C, Gao SM, Zhang R, Sun R, Li Y, Song Y. The retromer complex safeguards against neural progenitor-derived tumorigenesis by regulating Notch receptor trafficking. eLife 2018; 7:38181. [PMID: 30176986 PMCID: PMC6140715 DOI: 10.7554/elife.38181] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 08/17/2018] [Indexed: 12/14/2022] Open
Abstract
The correct establishment and maintenance of unidirectional Notch signaling are critical for the homeostasis of various stem cell lineages. However, the molecular mechanisms that prevent cell-autonomous ectopic Notch signaling activation and deleterious cell fate decisions remain unclear. Here we show that the retromer complex directly and specifically regulates Notch receptor retrograde trafficking in Drosophila neuroblast lineages to ensure the unidirectional Notch signaling from neural progenitors to neuroblasts. Notch polyubiquitination mediated by E3 ubiquitin ligase Itch/Su(dx) is inherently inefficient within neural progenitors, relying on retromer-mediated trafficking to avoid aberrant endosomal accumulation of Notch and cell-autonomous signaling activation. Upon retromer dysfunction, hypo-ubiquitinated Notch accumulates in Rab7+ enlarged endosomes, where it is ectopically processed and activated in a ligand-dependent manner, causing progenitor-originated tumorigenesis. Our results therefore unveil a safeguard mechanism whereby retromer retrieves potentially harmful Notch receptors in a timely manner to prevent aberrant Notch activation-induced neural progenitor dedifferentiation and brain tumor formation. Most cells in the animal body are tailored to perform particular tasks, but stem cells have not yet made their choice. Instead, they have unlimited capacity to divide and, with the right signals, they can start to specialize to become a given type of cells. In the brain, this process starts with a stem cell dividing. One of the daughters will remain a stem cell, while the other, the neural progenitor, will differentiate to form a mature cell such as a neuron. Keeping this tight balance is crucial for the health of the organ: if the progenitor reverts back to being a stem cell, there will be a surplus of undifferentiated cells that can lead to a tumor. A one-way signal driven by the protein Notch partly controls the distinct fates of the two daughter cells. While the neural progenitor carries Notch at its surface, its neural stem cell sister has a Notch receptor on its membrane instead. This ensures that the Notch signaling goes in one direction, from the cell with Notch to the one sporting the receptor. When a stem cell divides, one daughter gets more of a protein called Numb than the other. Numb pulls Notch receptors away from the external membrane and into internal capsules called endosomes. This guarantees that only one of the siblings will be carrying the receptors at its surface. Yet, sometimes the Notch receptors can get activated in the endosomes, which may make neural progenitors revert to being stem cells. It is still unclear what tools the cells have to stop this abnormal activation. Here, Li et al. screened brain cells from fruit fly larvae to find out the genes that might play a role in suppressing the inappropriate Notch signaling. This highlighted a protein complex known as the retromer, which normally helps to transport proteins in the cell. Experiments showed that, in progenitors, the retromer physically interacts with Notch receptors and retrieves them from the endosomes back to the cell surface. If the retromer is inactive, the Notch receptors accumulate in the endosomes, where they can be switched on. It seems that, in fruit flies, the retromer acts as a bomb squad that recognizes and retrieves potentially harmful Notch receptors, thereby preventing brain tumor formation. Several retromer components are less present in patients with various cancers, including glioblastoma, an aggressive form of brain cancer. The results by Li et al. may therefore shed light on the link between the protein complex and the emergence of the disease in humans.
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Affiliation(s)
- Bo Li
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, China
| | - Chouin Wong
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, China
| | - Shihong Max Gao
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, China
| | - Rulan Zhang
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, China
| | - Rongbo Sun
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China.,PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China.,PKU-IDG/McGovern Institute for Brain Research, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Yan Song
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
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26
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Rust K, Tiwari MD, Mishra VK, Grawe F, Wodarz A. Myc and the Tip60 chromatin remodeling complex control neuroblast maintenance and polarity in Drosophila. EMBO J 2018; 37:embj.201798659. [PMID: 29997178 DOI: 10.15252/embj.201798659] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 05/28/2018] [Accepted: 05/29/2018] [Indexed: 02/04/2023] Open
Abstract
Stem cells establish cortical polarity and divide asymmetrically to simultaneously maintain themselves and generate differentiating offspring cells. Several chromatin modifiers have been identified as stemness factors in mammalian pluripotent stem cells, but whether these factors control stem cell polarity and asymmetric division has not been investigated so far. We addressed this question in Drosophila neural stem cells called neuroblasts. We identified the Tip60 chromatin remodeling complex and its interaction partner Myc as regulators of genes required for neuroblast maintenance. Knockdown of Tip60 complex members results in loss of cortical polarity, symmetric neuroblast division, and premature differentiation through nuclear entry of the transcription factor Prospero. We found that aPKC is the key target gene of Myc and the Tip60 complex subunit Domino in regulating neuroblast polarity. Our transcriptome analysis further showed that Domino regulates the expression of mitotic spindle genes previously identified as direct Myc targets. Our findings reveal an evolutionarily conserved functional link between Myc, the Tip60 complex, and the molecular network controlling cell polarity and asymmetric cell division.
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Affiliation(s)
- Katja Rust
- Molecular Cell Biology, Institute I for Anatomy, University of Cologne Medical School, Cologne, Germany .,Cluster of Excellence-Cellular Stress Response in Aging-Associated Diseases (CECAD), Cologne, Germany.,Stem Cell Biology, Institute for Anatomy and Cell Biology, Georg-August University Göttingen, Göttingen, Germany.,Department of Anatomy and OB-GYN/RS, University of California, San Francisco, San Francisco, CA, USA
| | - Manu D Tiwari
- Molecular Cell Biology, Institute I for Anatomy, University of Cologne Medical School, Cologne, Germany.,Cluster of Excellence-Cellular Stress Response in Aging-Associated Diseases (CECAD), Cologne, Germany.,Stem Cell Biology, Institute for Anatomy and Cell Biology, Georg-August University Göttingen, Göttingen, Germany
| | - Vivek Kumar Mishra
- Department of Dermatology and the Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
| | - Ferdi Grawe
- Molecular Cell Biology, Institute I for Anatomy, University of Cologne Medical School, Cologne, Germany
| | - Andreas Wodarz
- Molecular Cell Biology, Institute I for Anatomy, University of Cologne Medical School, Cologne, Germany .,Cluster of Excellence-Cellular Stress Response in Aging-Associated Diseases (CECAD), Cologne, Germany.,Stem Cell Biology, Institute for Anatomy and Cell Biology, Georg-August University Göttingen, Göttingen, Germany
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27
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Wissel S, Harzer H, Bonnay F, Burkard TR, Neumüller RA, Knoblich JA. Time-resolved transcriptomics in neural stem cells identifies a v-ATPase/Notch regulatory loop. J Cell Biol 2018; 217:3285-3300. [PMID: 29959232 PMCID: PMC6123005 DOI: 10.1083/jcb.201711167] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 04/25/2018] [Accepted: 06/11/2018] [Indexed: 12/14/2022] Open
Abstract
Drosophila melanogaster neural stem cells (neuroblasts) divide asymmetrically by differentially segregating protein determinants into their daughter cells. Wissel et al. use time-resolved transcriptional profiling to identify a v-ATPase/Notch regulatory loop that acts in multiple stem cell lineages both during nervous system development and in the adult gut. Drosophila melanogaster neural stem cells (neuroblasts [NBs]) divide asymmetrically by differentially segregating protein determinants into their daughter cells. Although the machinery for asymmetric protein segregation is well understood, the events that reprogram one of the two daughter cells toward terminal differentiation are less clear. In this study, we use time-resolved transcriptional profiling to identify the earliest transcriptional differences between the daughter cells on their way toward distinct fates. By screening for coregulated protein complexes, we identify vacuolar-type H+–ATPase (v-ATPase) among the first and most significantly down-regulated complexes in differentiating daughter cells. We show that v-ATPase is essential for NB growth and persistent activity of the Notch signaling pathway. Our data suggest that v-ATPase and Notch form a regulatory loop that acts in multiple stem cell lineages both during nervous system development and in the adult gut. We provide a unique resource for investigating neural stem cell biology and demonstrate that cell fate changes can be induced by transcriptional regulation of basic, cell-essential pathways.
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Affiliation(s)
- Sebastian Wissel
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Heike Harzer
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - François Bonnay
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Thomas R Burkard
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Ralph A Neumüller
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Juergen A Knoblich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
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28
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Von Stetina JR, Frawley LE, Unhavaithaya Y, Orr-Weaver TL. Variant cell cycles regulated by Notch signaling control cell size and ensure a functional blood-brain barrier. Development 2018; 145:145/3/dev157115. [PMID: 29440220 PMCID: PMC5818001 DOI: 10.1242/dev.157115] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 01/09/2018] [Indexed: 12/31/2022]
Abstract
Regulation of cell size is crucial in development. In plants and animals two cell cycle variants are employed to generate large cells by increased ploidy: the endocycle and endomitosis. The rationale behind the choice of which of these cycles is implemented is unknown. We show that in the Drosophila nervous system the subperineurial glia (SPG) are unique in using both the endocycle and endomitosis to grow. In the brain, the majority of SPG initially endocycle, then switch to endomitosis during larval development. The Notch signaling pathway and the String Cdc25 phosphatase are crucial for the endocycle versus endomitosis choice, providing the means experimentally to change cells from one to the other. This revealed fundamental insights into the control of cell size and the properties of endomitotic cells. Endomitotic cells attain a higher ploidy and larger size than endocycling cells, and endomitotic SPG are necessary for the blood-brain barrier. Decreased Notch signaling promotes endomitosis even in the ventral nerve cord SPG that normally are mononucleate, but not in the endocycling salivary gland cells, revealing tissue-specific cell cycle responses. Highlighted Article: In Drosophila brain lobes, Notch and the mitosis-activating phosphatase String regulate the switch of subperineurial glia from endocycle to endomitosis during larval development, with endomitotic cells attaining increased ploidy and size.
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Affiliation(s)
| | - Laura E Frawley
- Whitehead Institute, Cambridge, MA 02142, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | | | - Terry L Orr-Weaver
- Whitehead Institute, Cambridge, MA 02142, USA .,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
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29
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Reichardt I, Bonnay F, Steinmann V, Loedige I, Burkard TR, Meister G, Knoblich JA. The tumor suppressor Brat controls neuronal stem cell lineages by inhibiting Deadpan and Zelda. EMBO Rep 2017; 19:102-117. [PMID: 29191977 DOI: 10.15252/embr.201744188] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 10/31/2017] [Accepted: 11/10/2017] [Indexed: 11/09/2022] Open
Abstract
The TRIM-NHL protein Brain tumor (Brat) acts as a tumor suppressor in the Drosophila brain, but how it suppresses tumor formation is not completely understood. Here, we combine temperature-controlled brat RNAi with transcriptome analysis to identify the immediate Brat targets in Drosophila neuroblasts. Besides the known target Deadpan (Dpn), our experiments identify the transcription factor Zelda (Zld) as a critical target of Brat. Our data show that Zld is expressed in neuroblasts and required to allow re-expression of Dpn in transit-amplifying intermediate neural progenitors. Upon neuroblast division, Brat is enriched in one daughter cell where its NHL domain directly binds to specific motifs in the 3'UTR of dpn and zld mRNA to mediate their degradation. In brat mutants, both Dpn and Zld continue to be expressed, but inhibition of either transcription factor prevents tumorigenesis. Our genetic and biochemical data indicate that Dpn inhibition requires higher Brat levels than Zld inhibition and suggest a model where stepwise post-transcriptional inhibition of distinct factors ensures sequential generation of fates in a stem cell lineage.
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Affiliation(s)
- Ilka Reichardt
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - François Bonnay
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - Victoria Steinmann
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - Inga Loedige
- Laboratory for RNA Biology, Biochemistry Center Regensburg (BZR), University of Regensburg, Regensburg, Germany
| | - Thomas R Burkard
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - Gunter Meister
- Laboratory for RNA Biology, Biochemistry Center Regensburg (BZR), University of Regensburg, Regensburg, Germany
| | - Juergen A Knoblich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
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30
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Li X, Chen R, Zhu S. bHLH-O proteins balance the self-renewal and differentiation of Drosophila neural stem cells by regulating Earmuff expression. Dev Biol 2017; 431:239-251. [PMID: 28899667 DOI: 10.1016/j.ydbio.2017.09.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 08/23/2017] [Accepted: 09/08/2017] [Indexed: 10/18/2022]
Abstract
Balancing self-renewal and differentiation of stem cells requires differential expression of self-renewing factors in two daughter cells generated from the asymmetric division of the stem cells. In Drosophila type II neural stem cell (or neuroblast, NB) lineages, the expression of the basic helix-loop-helix-Orange (bHLH-O) family proteins, including Deadpan (Dpn) and E(spl) proteins, is required for maintaining the self-renewal and identity of type II NBs, whereas the absence of these self-renewing factors is essential for the differentiation of intermediate neural progenitors (INPs) generated from type II NBs. Here, we demonstrate that Dpn maintains type II NBs by suppressing the expression of Earmuff (Erm). We provide evidence that Dpn and E(spl) proteins suppress Erm by directly binding to C-sites and N-boxes in the cis-regulatory region of erm. Conversely, the absence of bHLH-O proteins in INPs allows activation of erm and Erm-mediated maturation of INPs. Our results further suggest that Pointed P1 (PntP1) mediates the dedifferentiation of INPs resulting from the loss of Erm or overexpression of Dpn or E(spl) proteins. Taken together, these findings reveal mechanisms underlying the regulation of the maintenance of type II NBs and differentiation of INPs through the differential expression of bHLH-O family proteins.
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Affiliation(s)
- Xiaosu Li
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, United States
| | - Rui Chen
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, United States
| | - Sijun Zhu
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, United States.
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31
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Yang CP, Samuels TJ, Huang Y, Yang L, Ish-Horowicz D, Davis I, Lee T. Imp and Syp RNA-binding proteins govern decommissioning of Drosophila neural stem cells. Development 2017; 144:3454-3464. [PMID: 28851709 PMCID: PMC5665480 DOI: 10.1242/dev.149500] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 08/21/2017] [Indexed: 02/03/2023]
Abstract
The termination of the proliferation of Drosophila neural stem cells, also known as neuroblasts (NBs), requires a ‘decommissioning’ phase that is controlled in a lineage-specific manner. Most NBs, with the exception of those of the mushroom body (MB), are decommissioned by the ecdysone receptor and mediator complex, causing them to shrink during metamorphosis, followed by nuclear accumulation of Prospero and cell cycle exit. Here, we demonstrate that the levels of Imp and Syp RNA-binding proteins regulate NB decommissioning. Descending Imp and ascending Syp expression have been shown to regulate neuronal temporal fate. We show that Imp levels decline slower in the MB than in other central brain NBs. MB NBs continue to express Imp into pupation, and the presence of Imp prevents decommissioning partly by inhibiting the mediator complex. Late-larval induction of transgenic Imp prevents many non-MB NBs from decommissioning in early pupae. Moreover, the presence of abundant Syp in aged NBs permits Prospero accumulation that, in turn, promotes cell cycle exit. Together, our results reveal that progeny temporal fate and progenitor decommissioning are co-regulated in protracted neuronal lineages. Highlighted Article: Temporal progression of Imp/Syp gradients determines the timing of neuroblast decommissioning and cell cycle exit in addition to progeny temporal fate, allowing proper completion of a neuronal lineage.
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Affiliation(s)
- Ching-Po Yang
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Tamsin J Samuels
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Yaling Huang
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Lu Yang
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - David Ish-Horowicz
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.,MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Tzumin Lee
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
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32
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Liu K, Shen D, Shen J, Gao SM, Li B, Wong C, Feng W, Song Y. The Super Elongation Complex Drives Neural Stem Cell Fate Commitment. Dev Cell 2017; 40:537-551.e6. [PMID: 28350987 DOI: 10.1016/j.devcel.2017.02.022] [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: 08/25/2016] [Revised: 01/13/2017] [Accepted: 02/26/2017] [Indexed: 10/19/2022]
Abstract
Asymmetric stem cell division establishes an initial difference between a stem cell and its differentiating sibling, critical for maintaining homeostasis and preventing carcinogenesis. Yet the mechanisms that consolidate and lock in such initial fate bias remain obscure. Here, we use Drosophila neuroblasts to demonstrate that the super elongation complex (SEC) acts as an intrinsic amplifier to drive cell fate commitment. SEC is highly expressed in neuroblasts, where it promotes self-renewal by physically associating with Notch transcription activation complex and enhancing HES (hairy and E(spl)) transcription. HES in turn upregulates SEC activity, forming an unexpected self-reinforcing feedback loop with SEC. SEC inactivation leads to neuroblast loss, whereas its forced activation results in neural progenitor dedifferentiation and tumorigenesis. Our studies unveil an SEC-mediated intracellular amplifier mechanism in ensuring robustness and precision in stem cell fate commitment and provide mechanistic explanation for the highly frequent association of SEC overactivation with human cancers.
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Affiliation(s)
- Kun Liu
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Dan Shen
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Jingwen Shen
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Shihong M Gao
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Bo Li
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Chouin Wong
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Weidong Feng
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Yan Song
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China.
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33
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Wu YC, Lee KS, Song Y, Gehrke S, Lu B. The bantam microRNA acts through Numb to exert cell growth control and feedback regulation of Notch in tumor-forming stem cells in the Drosophila brain. PLoS Genet 2017; 13:e1006785. [PMID: 28520736 PMCID: PMC5453605 DOI: 10.1371/journal.pgen.1006785] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 06/01/2017] [Accepted: 04/27/2017] [Indexed: 12/19/2022] Open
Abstract
Notch (N) signaling is central to the self-renewal of neural stem cells (NSCs) and other tissue stem cells. Its deregulation compromises tissue homeostasis and contributes to tumorigenesis and other diseases. How N regulates stem cell behavior in health and disease is not well understood. Here we show that N regulates bantam (ban) microRNA to impact cell growth, a process key to NSC maintenance and particularly relied upon by tumor-forming cancer stem cells. Notch signaling directly regulates ban expression at the transcriptional level, and ban in turn feedback regulates N activity through negative regulation of the Notch inhibitor Numb. This feedback regulatory mechanism helps maintain the robustness of N signaling activity and NSC fate. Moreover, we show that a Numb-Myc axis mediates the effects of ban on nucleolar and cellular growth independently or downstream of N. Our results highlight intricate transcriptional as well as translational control mechanisms and feedback regulation in the N signaling network, with important implications for NSC biology and cancer biology.
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Affiliation(s)
- Yen-Chi Wu
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, United States of America
| | - Kyu-Sun Lee
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, United States of America
- BioNanotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
| | - Yan Song
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, United States of America
- School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Stephan Gehrke
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, United States of America
| | - Bingwei Lu
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, United States of America
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34
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Xie Y, Li X, Deng X, Hou Y, O'Hara K, Urso A, Peng Y, Chen L, Zhu S. The Ets protein Pointed prevents both premature differentiation and dedifferentiation of Drosophila intermediate neural progenitors. Development 2016; 143:3109-18. [PMID: 27510969 DOI: 10.1242/dev.137281] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 07/27/2016] [Indexed: 01/01/2023]
Abstract
Intermediate neural progenitors (INPs) need to avoid both dedifferentiation and differentiation during neurogenesis, but the underlying mechanisms are not well understood. In Drosophila, the Ets protein Pointed P1 (PntP1) is required to generate INPs from type II neuroblasts. Here, we investigated how PntP1 promotes INP generation. By generating pntP1-specific mutants and using RNAi knockdown, we show that the loss of PntP1 leads to both an increase in type II neuroblast number and the elimination of INPs. The elimination of INPs results from the premature differentiation of INPs due to ectopic Prospero expression in newly generated immature INPs (imINPs), whereas the increase in type II neuroblasts results from the dedifferentiation of imINPs due to loss of Earmuff at later stages of imINP development. Furthermore, reducing Buttonhead enhances the loss of INPs in pntP1 mutants, suggesting that PntP1 and Buttonhead act cooperatively to prevent premature INP differentiation. Our results demonstrate that PntP1 prevents both the premature differentiation and the dedifferentiation of INPs by regulating the expression of distinct target genes at different stages of imINP development.
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Affiliation(s)
- Yonggang Xie
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
| | - Xiaosu Li
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
| | - Xiaobing Deng
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
| | - Yanjun Hou
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
| | - Krysten O'Hara
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
| | | | - Ying Peng
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Li Chen
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
| | - Sijun Zhu
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
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35
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Li X, Xie Y, Zhu S. Notch maintains Drosophila type II neuroblasts by suppressing expression of the Fez transcription factor Earmuff. Development 2016; 143:2511-21. [PMID: 27151950 DOI: 10.1242/dev.136184] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 04/26/2016] [Indexed: 01/10/2023]
Abstract
Notch signaling is crucial for maintaining neural stem cell (NSC) self-renewal and heterogeneity; however, the underlying mechanism is not well understood. In Drosophila, loss of Notch prematurely terminates the self-renewal of larval type II neuroblasts (NBs, the Drosophila NSCs) and transforms type II NBs into type I NBs. Here, we demonstrate that Notch maintains type II NBs by suppressing the activation of earmuff (erm) by Pointed P1 (PntP1). We show that loss of Notch or components of its canonical pathway leads to PntP1-dependent ectopic Erm expression in type II NBs. Knockdown of Erm significantly rescues the loss-of-Notch phenotypes, and misexpression of Erm phenocopies the loss of Notch. Ectopically expressed Erm promotes the transformation of type II NBs into type I NBs by inhibiting PntP1 function and expression in type II NBs. Our work not only elucidates a key mechanism of Notch-mediated maintenance of type II NB self-renewal and identity, but also reveals a novel function of Erm.
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Affiliation(s)
- Xiaosu Li
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
| | - Yonggang Xie
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
| | - Sijun Zhu
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
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36
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Lee S, Lee KS, Huh S, Liu S, Lee DY, Hong SH, Yu K, Lu B. Polo Kinase Phosphorylates Miro to Control ER-Mitochondria Contact Sites and Mitochondrial Ca(2+) Homeostasis in Neural Stem Cell Development. Dev Cell 2016; 37:174-189. [PMID: 27093086 PMCID: PMC4839004 DOI: 10.1016/j.devcel.2016.03.023] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 03/11/2016] [Accepted: 03/23/2016] [Indexed: 02/08/2023]
Abstract
Mitochondria play central roles in buffering intracellular Ca²⁺ transients. While basal mitochondrial Ca²⁺ (Ca²⁺ mito) is needed to maintain organellar physiology, Ca²⁺ mito overload can lead to cell death. How Ca²⁺ mito homeostasis is regulated is not well understood. Here we show that Miro, a known component of the mitochondrial transport machinery, regulates Drosophila neural stem cell (NSC) development through Ca²⁺ mito homeostasis control, independent of its role in mitochondrial transport. Miro interacts with Ca²⁺ transporters at the ER-mitochondria contact site (ERMCS). Its inactivation causes Ca²⁺ mito depletion and metabolic impairment, whereas its overexpression results in Ca²⁺ mito overload, mitochondrial morphology change, and apoptotic response. Both conditions impaired NSC lineage progression. Ca²⁺ mito homeostasis is influenced by Polo-mediated phosphorylation of a conserved residue in Miro, which positively regulates Miro localization to, and the integrity of, ERMCS. Our results elucidate a regulatory mechanism underlying Ca²⁺ mito homeostasis and how its dysregulation may affect NSC metabolism/development and contribute to disease.
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Affiliation(s)
- Seongsoo Lee
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
- BioNanotechnology Research Center, Korea Research Institute of Biotechnology and Bioscience, Daejeon, 305-806, Korea
| | - Kyu-Sun Lee
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
- BioNanotechnology Research Center, Korea Research Institute of Biotechnology and Bioscience, Daejeon, 305-806, Korea
| | - Sungun Huh
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Song Liu
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Do-Yeon Lee
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Seung Hyun Hong
- BioNanotechnology Research Center, Korea Research Institute of Biotechnology and Bioscience, Daejeon, 305-806, Korea
| | - Kweon Yu
- BioNanotechnology Research Center, Korea Research Institute of Biotechnology and Bioscience, Daejeon, 305-806, Korea
| | - Bingwei Lu
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
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37
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Froldi F, Cheng LY. Understanding how differentiation is maintained: lessons from the Drosophila brain. Cell Mol Life Sci 2016; 73:1641-4. [PMID: 26817462 PMCID: PMC11108259 DOI: 10.1007/s00018-016-2144-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 01/14/2016] [Accepted: 01/18/2016] [Indexed: 12/19/2022]
Abstract
The ability to maintain cells in a differentiated state and to prevent them from reprogramming into a multipotent state has recently emerged as a central theme in neural development as well as in oncogenesis. In the developing central nervous system (CNS) of the fruit fly Drosophila, several transcription factors were recently identified to be required in postmitotic cells to maintain differentiation, and in their absence, mature neurons undergo dedifferentiation, giving rise to proliferative neural stem cells and ultimately to tumor growth. In this review, we will highlight the current understanding of dedifferentiation and cell plasticity in the Drosophila CNS.
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Affiliation(s)
- Francesca Froldi
- Peter MacCallum Cancer Centre, East Melbourne, VIC, 3002, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Louise Y Cheng
- Peter MacCallum Cancer Centre, East Melbourne, VIC, 3002, Australia.
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, VIC, 3010, Australia.
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38
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Zacharioudaki E, Housden BE, Garinis G, Stojnic R, Delidakis C, Bray SJ. Genes implicated in stem cell identity and temporal programme are directly targeted by Notch in neuroblast tumours. Development 2015; 143:219-31. [PMID: 26657768 PMCID: PMC4725341 DOI: 10.1242/dev.126326] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 12/02/2015] [Indexed: 01/03/2023]
Abstract
Notch signalling is involved in a multitude of developmental decisions and its aberrant activation is linked to many diseases, including cancers. One example is the neural stem cell tumours that arise from constitutive Notch activity in Drosophila neuroblasts. To investigate how hyperactivation of Notch in larval neuroblasts leads to tumours, we combined results from profiling the upregulated mRNAs and mapping the regions bound by the core Notch pathway transcription factor Su(H). This identified 246 putative direct Notch targets. These genes were highly enriched for transcription factors and overlapped significantly with a previously identified regulatory programme dependent on the proneural transcription factor Asense. Included were genes associated with the neuroblast maintenance and self-renewal programme that we validated as Notch regulated in vivo. Another group were the so-called temporal transcription factors, which have been implicated in neuroblast maturation. Normally expressed in specific time windows, several temporal transcription factors were ectopically expressed in the stem cell tumours, suggesting that Notch had reprogrammed their normal temporal regulation. Indeed, the Notch-induced hyperplasia was reduced by mutations affecting two of the temporal factors, which, conversely, were sufficient to induce mild hyperplasia on their own. Altogether, the results suggest that Notch induces neuroblast tumours by directly promoting the expression of genes that contribute to stem cell identity and by reprogramming the expression of factors that could regulate maturity.
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Affiliation(s)
- Evanthia Zacharioudaki
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK Institute of Molecular Biology and Biotechnology, FORTH-Hellas, Heraklion, Crete 70013, Greece Department of Biology, University of Crete, Heraklion, Greece GR71409
| | - Benjamin E Housden
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - George Garinis
- Institute of Molecular Biology and Biotechnology, FORTH-Hellas, Heraklion, Crete 70013, Greece Department of Biology, University of Crete, Heraklion, Greece GR71409
| | - Robert Stojnic
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK Cambridge Systems Biology Centre, University of Cambridge, Cambridge CB2 1QR, UK
| | - Christos Delidakis
- Institute of Molecular Biology and Biotechnology, FORTH-Hellas, Heraklion, Crete 70013, Greece Department of Biology, University of Crete, Heraklion, Greece GR71409
| | - Sarah J Bray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
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Farnsworth DR, Bayraktar OA, Doe CQ. Aging Neural Progenitors Lose Competence to Respond to Mitogenic Notch Signaling. Curr Biol 2015; 25:3058-68. [PMID: 26585279 DOI: 10.1016/j.cub.2015.10.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 10/07/2015] [Accepted: 10/12/2015] [Indexed: 12/21/2022]
Abstract
Drosophila neural stem cells (neuroblasts) are a powerful model system for investigating stem cell self-renewal, specification of temporal identity, and progressive restriction in competence. Notch signaling is a conserved cue that is an important determinant of cell fate in many contexts across animal development; for example, mammalian T cell differentiation in the thymus and neuroblast specification in Drosophila are both regulated by Notch signaling. However, Notch also functions as a mitogen, and constitutive Notch signaling potentiates T cell leukemia as well as Drosophila neuroblast tumors. While the role of Notch signaling has been studied in these and other cell types, it remains unclear how stem cells and progenitors change competence to respond to Notch over time. Notch is required in type II neuroblasts for normal development of their transit amplifying progeny, intermediate neural progenitors (INPs). Here, we find that aging INPs lose competence to respond to constitutively active Notch signaling. Moreover, we show that reducing the levels of the old INP temporal transcription factor Eyeless/Pax6 allows Notch signaling to promote the de-differentiation of INP progeny into ectopic INPs, thereby creating a proliferative mass of ectopic progenitors in the brain. These findings provide a new system for studying progenitor competence and identify a novel role for the conserved transcription factor Eyeless/Pax6 in blocking Notch signaling during development.
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Affiliation(s)
- Dylan R Farnsworth
- Howard Hughes Medical Institute, University of Oregon, Eugene, OR 97403, USA; Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Omer Ali Bayraktar
- Howard Hughes Medical Institute, University of Oregon, Eugene, OR 97403, USA; Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA; Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Chris Q Doe
- Howard Hughes Medical Institute, University of Oregon, Eugene, OR 97403, USA; Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA; Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA.
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40
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Friday AJ, Henderson MA, Morrison JK, Hoffman JL, Keiper BD. Spatial and temporal translational control of germ cell mRNAs mediated by the eIF4E isoform IFE-1. J Cell Sci 2015; 128:4487-98. [PMID: 26542024 DOI: 10.1242/jcs.172684] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 11/02/2015] [Indexed: 11/20/2022] Open
Abstract
Regulated mRNA translation is vital for germ cells to produce new proteins in the spatial and temporal patterns that drive gamete development. Translational control involves the de-repression of stored mRNAs and their recruitment by eukaryotic initiation factors (eIFs) to ribosomes. C. elegans expresses five eIF4Es (IFE-1-IFE-5); several have been shown to selectively recruit unique pools of mRNA. Individual IFE knockouts yield unique phenotypes due to inefficient translation of certain mRNAs. Here, we identified mRNAs preferentially translated through the germline-specific eIF4E isoform IFE-1. Differential polysome microarray analysis identified 77 mRNAs recruited by IFE-1. Among the IFE-1-dependent mRNAs are several required for late germ cell differentiation and maturation. Polysome association of gld-1, vab-1, vpr-1, rab-7 and rnp-3 mRNAs relies on IFE-1. Live animal imaging showed IFE-1-dependent selectivity in spatial and temporal translation of germline mRNAs. Altered MAPK activation in oocytes suggests dual roles for IFE-1, both promoting and suppressing oocyte maturation at different stages. This single eIF4E isoform exerts positive, selective translational control during germ cell differentiation.
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Affiliation(s)
- Andrew J Friday
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - Melissa A Henderson
- Department of Molecular Sciences, DeBusk College of Osteopathic Medicine, Lincoln Memorial University, Harrogate, TN 37752, USA
| | - J Kaitlin Morrison
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - Jenna L Hoffman
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
| | - Brett D Keiper
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, NC 27834, USA
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Homem CCF, Repic M, Knoblich JA. Proliferation control in neural stem and progenitor cells. Nat Rev Neurosci 2015; 16:647-59. [PMID: 26420377 DOI: 10.1038/nrn4021] [Citation(s) in RCA: 236] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neural circuit function can be drastically affected by variations in the number of cells that are produced during development or by a reduction in adult cell number owing to disease. For this reason, unique cell cycle and cell growth control mechanisms operate in the developing and adult brain. In Drosophila melanogaster and in mammalian neural stem and progenitor cells, these mechanisms are intricately coordinated with the developmental age and the nutritional, metabolic and hormonal state of the animal. Defects in neural stem cell proliferation that result in the generation of incorrect cell numbers or defects in neural stem cell differentiation can cause microcephaly or megalencephaly.
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Affiliation(s)
- Catarina C F Homem
- Institute of Molecular Biotechnology, Dr. Bohr Gasse 3, 1030, Vienna, Austria.,Chronic Diseases Research Center, NOVA Medical School, Rua Camara Pestana, 6, 1150-082 Lisbon, Portugal
| | - Marko Repic
- Institute of Molecular Biotechnology, Dr. Bohr Gasse 3, 1030, Vienna, Austria
| | - Jürgen A Knoblich
- Institute of Molecular Biotechnology, Dr. Bohr Gasse 3, 1030, Vienna, Austria
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Li Q, Rycaj K, Chen X, Tang DG. Cancer stem cells and cell size: A causal link? Semin Cancer Biol 2015; 35:191-9. [PMID: 26241348 DOI: 10.1016/j.semcancer.2015.07.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 07/08/2015] [Indexed: 12/18/2022]
Abstract
The majority of normal animal cells are 10-20 μm in diameter. Many signaling mechanisms, notably PI3K/Akt/mTOR, Myc, and Hippo pathways, tightly control and coordinate cell growth, cell size, cell division, and cell number during homeostasis. These regulatory mechanisms are frequently deregulated during tumorigenesis resulting in wide variations in cell sizes and increased proliferation in cancer cells. Here, we first review the evidence that primitive stem cells in adult tissues are quiescent and generally smaller than their differentiated progeny, suggesting a correlation between small cell sizes with the stemness. Conversely, increased cell size positively correlates with differentiation phenotypes. We then discuss cancer stem cells (CSCs) and present some evidence that correlates cell sizes with CSC activity. Overall, a causal link between CSCs and cell size is relatively weak and remains to be rigorously assessed. In the future, optimizing methods for isolating cells based on size should help elucidate the connection between cancer cell size and CSC characteristics.
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Affiliation(s)
- Qiuhui Li
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park, Smithville, TX 78957, USA
| | - Kiera Rycaj
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park, Smithville, TX 78957, USA
| | - Xin Chen
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park, Smithville, TX 78957, USA.
| | - Dean G Tang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park, Smithville, TX 78957, USA; Cancer Stem Cell Institute, Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.
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Yuva-Aydemir Y, Xu XL, Aydemir O, Gascon E, Sayin S, Zhou W, Hong Y, Gao FB. Downregulation of the Host Gene jigr1 by miR-92 Is Essential for Neuroblast Self-Renewal in Drosophila. PLoS Genet 2015; 11:e1005264. [PMID: 26000445 PMCID: PMC4441384 DOI: 10.1371/journal.pgen.1005264] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 05/05/2015] [Indexed: 11/18/2022] Open
Abstract
Intragenic microRNAs (miRNAs), located mostly in the introns of protein-coding genes, are often co-expressed with their host mRNAs. However, their functional interaction in development is largely unknown. Here we show that in Drosophila, miR-92a and miR-92b are embedded in the intron and 3'UTR of jigr1, respectively, and co-expressed with some jigr1 isoforms. miR-92a and miR-92b are highly expressed in neuroblasts of larval brain where Jigr1 expression is low. Genetic deletion of both miR-92a and miR-92b demonstrates an essential cell-autonomous role for these miRNAs in maintaining neuroblast self-renewal through inhibiting premature differentiation. We also show that miR-92a and miR-92b directly target jigr1 in vivo and that some phenotypes due to the absence of these miRNAs are partially rescued by reducing the level of jigr1. These results reveal a novel function of the miR-92 family in Drosophila neuroblasts and provide another example that local negative feedback regulation of host genes by intragenic miRNAs is essential for animal development.
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Affiliation(s)
- Yeliz Yuva-Aydemir
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Xia-Lian Xu
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
| | - Ozkan Aydemir
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Eduardo Gascon
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Serkan Sayin
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Wenke Zhou
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Yang Hong
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Fen-Biao Gao
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
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Froldi F, Szuperak M, Weng CF, Shi W, Papenfuss AT, Cheng LY. The transcription factor Nerfin-1 prevents reversion of neurons into neural stem cells. Genes Dev 2015; 29:129-43. [PMID: 25593306 PMCID: PMC4298133 DOI: 10.1101/gad.250282.114] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Froldi et al. show that the Drosophila zinc finger transcription factor Nervous fingers 1 (Nerfin-1) locks neurons into differentiation, preventing their reversion into neuroblasts. The loss of Nerfin-1 causes reversion to multipotency and results in tumors in several neural lineages. RNA-seq and ChIP analysis show that Nerfin-1 administers its function by repression of self-renewing genes and activation of differentiation-specific genes. Cellular dedifferentiation is the regression of a cell from a specialized state to a more multipotent state and is implicated in cancer. However, the transcriptional network that prevents differentiated cells from reacquiring stem cell fate is so far unclear. Neuroblasts (NBs), the Drosophila neural stem cells, are a model for the regulation of stem cell self-renewal and differentiation. Here we show that the Drosophila zinc finger transcription factor Nervous fingers 1 (Nerfin-1) locks neurons into differentiation, preventing their reversion into NBs. Following Prospero-dependent neuronal specification in the ganglion mother cell (GMC), a Nerfin-1-specific transcriptional program maintains differentiation in the post-mitotic neurons. The loss of Nerfin-1 causes reversion to multipotency and results in tumors in several neural lineages. Both the onset and rate of neuronal dedifferentiation in nerfin-1 mutant lineages are dependent on Myc- and target of rapamycin (Tor)-mediated cellular growth. In addition, Nerfin-1 is required for NB differentiation at the end of neurogenesis. RNA sequencing (RNA-seq) and chromatin immunoprecipitation (ChIP) analysis show that Nerfin-1 administers its function by repression of self-renewing-specific and activation of differentiation-specific genes. Our findings support the model of bidirectional interconvertibility between neural stem cells and their post-mitotic progeny and highlight the importance of the Nerfin-1-regulated transcriptional program in neuronal maintenance.
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Affiliation(s)
- Francesca Froldi
- Peter MacCallum Cancer Centre, East Melbourne, Victoria 3002, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Milan Szuperak
- Peter MacCallum Cancer Centre, East Melbourne, Victoria 3002, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Chen-Fang Weng
- Peter MacCallum Cancer Centre, East Melbourne, Victoria 3002, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Wei Shi
- Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Computing and Information Systems, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Anthony T Papenfuss
- Peter MacCallum Cancer Centre, East Melbourne, Victoria 3002, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia; Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Louise Y Cheng
- Peter MacCallum Cancer Centre, East Melbourne, Victoria 3002, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia;
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Abstract
Stem cells give rise to tissues and organs during development and maintain their integrity during adulthood. They have the potential to self-renew or differentiate at each division. To ensure proper organ growth and homeostasis, self-renewal versus differentiation decisions need to be tightly controlled. Systematic genetic studies in Drosophila melanogaster are revealing extensive regulatory networks that control the switch between stem cell self-renewal and differentiation in the germline. These networks, which are based primarily on mutual translational repression, act via interlocked feedback loops to provide robustness to this important fate decision.
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Affiliation(s)
- Maija Slaidina
- Howard Hughes Medical Institute and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016 Howard Hughes Medical Institute and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016
| | - Ruth Lehmann
- Howard Hughes Medical Institute and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016 Howard Hughes Medical Institute and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016
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46
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Drosophila neuroblasts as a new model for the study of stem cell self-renewal and tumour formation. Biosci Rep 2014; 34:BSR20140008. [PMID: 24965943 PMCID: PMC4114065 DOI: 10.1042/bsr20140008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Drosophila larval brain stem cells (neuroblasts) have emerged as an important model for the study of stem cell asymmetric division and the mechanisms underlying the transformation of neural stem cells into tumour-forming cancer stem cells. Each Drosophila neuroblast divides asymmetrically to produce a larger daughter cell that retains neuroblast identity, and a smaller daughter cell that is committed to undergo differentiation. Neuroblast self-renewal and differentiation are tightly controlled by a set of intrinsic factors that regulate ACD (asymmetric cell division). Any disruption of these two processes may deleteriously affect the delicate balance between neuroblast self-renewal and progenitor cell fate specification and differentiation, causing neuroblast overgrowth and ultimately lead to tumour formation in the fly. In this review, we discuss the mechanisms underlying Drosophila neural stem cell self-renewal and differentiation. Furthermore, we highlight emerging evidence in support of the notion that defects in ACD in mammalian systems, which may play significant roles in the series of pathogenic events leading to the development of brain cancers.
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47
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Jiang Y, Reichert H. DrosophilaNeural Stem Cells in Brain Development and Tumor Formation. J Neurogenet 2014; 28:181-9. [DOI: 10.3109/01677063.2014.898639] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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48
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Eroglu E, Burkard TR, Jiang Y, Saini N, Homem CCF, Reichert H, Knoblich JA. SWI/SNF complex prevents lineage reversion and induces temporal patterning in neural stem cells. Cell 2014; 156:1259-1273. [PMID: 24630726 DOI: 10.1016/j.cell.2014.01.053] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 11/11/2013] [Accepted: 01/16/2014] [Indexed: 12/22/2022]
Abstract
Members of the SWI/SNF chromatin-remodeling complex are among the most frequently mutated genes in human cancer, but how they suppress tumorigenesis is currently unclear. Here, we use Drosophila neuroblasts to demonstrate that the SWI/SNF component Osa (ARID1) prevents tumorigenesis by ensuring correct lineage progression in stem cell lineages. We show that Osa induces a transcriptional program in the transit-amplifying population that initiates temporal patterning, limits self-renewal, and prevents dedifferentiation. We identify the Prdm protein Hamlet as a key component of this program. Hamlet is directly induced by Osa and regulates the progression of progenitors through distinct transcriptional states to limit the number of transit-amplifying divisions. Our data provide a mechanistic explanation for the widespread tumor suppressor activity of SWI/SNF. Because the Hamlet homologs Evi1 and Prdm16 are frequently mutated in cancer, this mechanism could well be conserved in human stem cell lineages. PAPERCLIP:
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Affiliation(s)
- Elif Eroglu
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Thomas R Burkard
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Yanrui Jiang
- Biozentrum, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Nidhi Saini
- Biozentrum, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Catarina C F Homem
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Heinrich Reichert
- Biozentrum, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Juergen A Knoblich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030 Vienna, Austria.
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49
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It takes two to tango, a dance between the cells of origin and cancer stem cells in the Drosophila larval brain. Semin Cell Dev Biol 2014; 28:63-9. [PMID: 24631354 DOI: 10.1016/j.semcdb.2014.03.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 03/03/2014] [Indexed: 01/12/2023]
Abstract
During malignant transformation the cells of origin give rise to cancer stem cells which possess the capacity to undergo limitless rounds of self-renewing division, regenerating themselves while producing more tumor cells. Within normal tissues, a limitless self-renewal capacity is unique to the stem cells, which divide asymmetrically to produce more restricted progenitors. Accumulating evidence suggests that misregulation of the self-renewal machinery in stem cell progeny can lead to tumorigenesis, but how it influences the properties of the resulting tumors remains unclear. Studies of the type II neural stem cell (neuroblast) lineages in the Drosophila larval brain have identified a regulatory cascade that promotes commitment to a progenitor cell identity by restricting their response to the self-renewal machinery. Brain tumor (Brat) and Numb initiate this cascade by asymmetrically extinguishing the activity of the self-renewal factors. Subsequently, Earmuff (Erm) and the SWI/SNF complex stably restrict the competence of the progenitor cell to respond to reactivation of self-renewal mechanisms. Together, this cascade programs the progenitor cell to undergo limited rounds of division, generating exclusive differentiated progeny. Here we review how defects in this cascade lead to tumor initiation and how inhibiting the self-renewal mechanisms may be an effective strategy to block CSC expansion.
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50
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Drosophila mbm is a nucleolar myc and casein kinase 2 target required for ribosome biogenesis and cell growth of central brain neuroblasts. Mol Cell Biol 2014; 34:1878-91. [PMID: 24615015 DOI: 10.1128/mcb.00658-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Proper cell growth is a prerequisite for maintaining repeated cell divisions. Cells need to translate information about intracellular nutrient availability and growth cues from energy-sensing organs into growth-promoting processes, such as sufficient supply with ribosomes for protein synthesis. Mutations in the mushroom body miniature (mbm) gene impair proliferation of neural progenitor cells (neuroblasts) in the central brain of Drosophila melanogaster. Yet the molecular function of Mbm has so far been unknown. Here we show that mbm does not affect the molecular machinery controlling asymmetric cell division of neuroblasts but instead decreases their cell size. Mbm is a nucleolar protein required for small ribosomal subunit biogenesis in neuroblasts. Accordingly, levels of protein synthesis are reduced in mbm neuroblasts. Mbm expression is transcriptionally regulated by Myc, which, among other functions, relays information from nutrient-dependent signaling pathways to ribosomal gene expression. At the posttranslational level, Mbm becomes phosphorylated by casein kinase 2 (CK2), which has an impact on localization of the protein. We conclude that Mbm is a new part of the Myc target network involved in ribosome biogenesis, which, together with CK2-mediated signals, enables neuroblasts to synthesize sufficient amounts of proteins required for proper cell growth.
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