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Duan S, Sawyer TW, Sontz RA, Wieland BA, Diaz AF, Merchant JL. GFAP-directed Inactivation of Men1 Exploits Glial Cell Plasticity in Favor of Neuroendocrine Reprogramming. Cell Mol Gastroenterol Hepatol 2022; 14:1025-1051. [PMID: 35835391 PMCID: PMC9490044 DOI: 10.1016/j.jcmgh.2022.06.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 06/16/2022] [Accepted: 06/28/2022] [Indexed: 01/31/2023]
Abstract
BACKGROUND & AIMS Efforts to characterize the signaling mechanisms that underlie gastroenteropancreatic neoplasms (GEP-NENs) are precluded by a lack of comprehensive models that recapitulate pathogenesis. Investigation into a potential cell-of-origin for gastrin-secreting NENs revealed a non-cell autonomous role for loss of menin in neuroendocrine cell specification, resulting in an induction of gastrin in enteric glia. Here, we investigated the hypothesis that cell autonomous Men1 inactivation in glial fibrillary acidic protein (GFAP)-expressing cells induced neuroendocrine differentiation and tumorigenesis. METHODS Transgenic GFAPΔMen1 mice were generated by conditional GFAP-directed Men1 deletion in GFAP-expressing cells. Cre specificity was confirmed using a tdTomato reporter. GFAPΔMen1 mice were evaluated for GEP-NEN development and neuroendocrine cell hyperplasia. Small interfering RNA-mediated Men1 silencing in a rat enteric glial cell line was performed in parallel. RESULTS GFAPΔMen1 mice developed pancreatic NENs, in addition to pituitary prolactinomas that phenocopied the human MEN1 syndrome. GFAPΔMen1 mice exhibited gastric neuroendocrine hyperplasia that coincided with a significant loss of GFAP expression. Men1 deletion induced loss of glial-restricted progenitor lineage markers and an increase in neuroendocrine genes, suggesting a reprogramming of GFAP+ cells. Deleting Kif3a, a mediator of Hedgehog signaling, in GFAP-expressing cells attenuated neuroendocrine hyperplasia by restricting the neuroendocrine cell fate. Similar results in the pancreas were observed when Sox10 was used to delete Men1. CONCLUSIONS GFAP-directed Men1 inactivation exploits glial cell plasticity in favor of neuroendocrine differentiation.
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Affiliation(s)
- Suzann Duan
- University of Arizona College of Medicine, Department of Medicine, Division of Gastroenterology, Tucson, Arizona
| | - Travis W. Sawyer
- Wyant College of Optical Sciences, University of Arizona, Tucson, Arizona
| | - Ricky A. Sontz
- University of Arizona College of Medicine, Department of Medicine, Division of Gastroenterology, Tucson, Arizona
| | - Bradley A. Wieland
- University of Arizona College of Medicine, Department of Medicine, Division of Gastroenterology, Tucson, Arizona
| | - Andres F. Diaz
- University of Arizona College of Medicine, Department of Medicine, Division of Gastroenterology, Tucson, Arizona
| | - Juanita L. Merchant
- University of Arizona College of Medicine, Department of Medicine, Division of Gastroenterology, Tucson, Arizona,Correspondence Address correspondence to: Dr Juanita L. Merchant, University of Arizona, 1515 N. Campbell Ave, Tucson, AZ 85724; tel: (520) 626-7897; fax: (520) 626-1291.
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2
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Stefanovic S, Laforest B, Desvignes JP, Lescroart F, Argiro L, Maurel-Zaffran C, Salgado D, Plaindoux E, De Bono C, Pazur K, Théveniau-Ruissy M, Béroud C, Puceat M, Gavalas A, Kelly RG, Zaffran S. Hox-dependent coordination of mouse cardiac progenitor cell patterning and differentiation. eLife 2020; 9:55124. [PMID: 32804075 PMCID: PMC7462617 DOI: 10.7554/elife.55124] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 08/16/2020] [Indexed: 12/15/2022] Open
Abstract
Perturbation of addition of second heart field (SHF) cardiac progenitor cells to the poles of the heart tube results in congenital heart defects (CHD). The transcriptional programs and upstream regulatory events operating in different subpopulations of the SHF remain unclear. Here, we profile the transcriptome and chromatin accessibility of anterior and posterior SHF sub-populations at genome-wide levels and demonstrate that Hoxb1 negatively regulates differentiation in the posterior SHF. Spatial mis-expression of Hoxb1 in the anterior SHF results in hypoplastic right ventricle. Activation of Hoxb1 in embryonic stem cells arrests cardiac differentiation, whereas Hoxb1-deficient mouse embryos display premature cardiac differentiation. Moreover, ectopic differentiation in the posterior SHF of embryos lacking both Hoxb1 and its paralog Hoxa1 results in atrioventricular septal defects. Our results show that Hoxb1 plays a key role in patterning cardiac progenitor cells that contribute to both cardiac poles and provide new insights into the pathogenesis of CHD.
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Affiliation(s)
- Sonia Stefanovic
- Aix Marseille Univ, INSERM, Marseille Medical Genetics, Marseille, France
| | - Brigitte Laforest
- Aix Marseille Univ, INSERM, Marseille Medical Genetics, Marseille, France
| | | | - Fabienne Lescroart
- Aix Marseille Univ, INSERM, Marseille Medical Genetics, Marseille, France
| | - Laurent Argiro
- Aix Marseille Univ, INSERM, Marseille Medical Genetics, Marseille, France
| | | | - David Salgado
- Aix Marseille Univ, INSERM, Marseille Medical Genetics, Marseille, France
| | - Elise Plaindoux
- Aix Marseille Univ, INSERM, Marseille Medical Genetics, Marseille, France
| | | | - Kristijan Pazur
- Paul Langerhans Institute Dresden (PLID) of Helmholtz Center Munich at the University Clinic Carl Gustave Carus of TU Dresden, Helmoholtz Zentrum München, German Center for Diabetes Research (DZD), Dresden, Germany
| | - Magali Théveniau-Ruissy
- Aix Marseille Univ, INSERM, Marseille Medical Genetics, Marseille, France.,Aix Marseille Univ, CNRS UMR7288, IBDM, Marseille, France
| | - Christophe Béroud
- Aix Marseille Univ, INSERM, Marseille Medical Genetics, Marseille, France
| | - Michel Puceat
- Aix Marseille Univ, INSERM, Marseille Medical Genetics, Marseille, France
| | - Anthony Gavalas
- Paul Langerhans Institute Dresden (PLID) of Helmholtz Center Munich at the University Clinic Carl Gustave Carus of TU Dresden, Helmoholtz Zentrum München, German Center for Diabetes Research (DZD), Dresden, Germany
| | - Robert G Kelly
- Aix Marseille Univ, CNRS UMR7288, IBDM, Marseille, France
| | - Stephane Zaffran
- Aix Marseille Univ, INSERM, Marseille Medical Genetics, Marseille, France
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3
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Ghosh P, Maurer JM, Sagerström CG. Analysis of novel caudal hindbrain genes reveals different regulatory logic for gene expression in rhombomere 4 versus 5/6 in embryonic zebrafish. Neural Dev 2018; 13:13. [PMID: 29945667 PMCID: PMC6020313 DOI: 10.1186/s13064-018-0112-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 06/19/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Previous work aimed at understanding the gene regulatory networks (GRNs) governing caudal hindbrain formation identified morphogens such as Retinoic Acid (RA) and Fibroblast growth factors (FGFs), as well as transcription factors like hoxb1b, hoxb1a, hnf1ba, and valentino as being required for rhombomere (r) r4-r6 formation in zebrafish. Considering that the caudal hindbrain is relatively complex - for instance, unique sets of neurons are formed in each rhombomere segment - it is likely that additional essential genes remain to be identified and integrated into the caudal hindbrain GRN. METHODS By taking advantage of gene expression data available in the Zebrafish Information Network (ZFIN), we identified 84 uncharacterized genes that are expressed in r4-r6. We selected a representative set of 22 genes and assayed their expression patterns in hoxb1b, hoxb1a, hnf1b, and valentino mutants with the goal of positioning them in the caudal hindbrain GRN. We also investigated the effects of RA and FGF on the expression of this gene set. To examine whether these genes are necessary for r4-r6 development, we analyzed germline mutants for six of the genes (gas6, gbx1, sall4, eglf6, celf2, and greb1l) for defects in hindbrain development. RESULTS Our results reveal that r4 gene expression is unaffected by the individual loss of hoxb1b, hoxb1a or RA, but is under the combinatorial regulation of RA together with hoxb1b. In contrast, r5/r6 gene expression is dependent on RA, FGF, hnf1ba and valentino - as individual loss of these factors abolishes r5/r6 gene expression. Our analysis of six mutant lines did not reveal rhombomere or neuronal defects, but transcriptome analysis of one line (gas6 mutant) identified expression changes for genes involved in several developmental processes - suggesting that these genes may have subtle roles in hindbrain development. CONCLUSION We conclude that r4-r6 formation is relatively robust, such that very few genes are absolutely required for this process. However, there are mechanistic differences in r4 versus r5/r6, such that no single factor is required for r4 development while several genes are individually required for r5/r6 formation.
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Affiliation(s)
- Priyanjali Ghosh
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation St/LRB815, Worcester, MA, USA
| | - Jennifer M Maurer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation St/LRB815, Worcester, MA, USA
| | - Charles G Sagerström
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation St/LRB815, Worcester, MA, USA.
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4
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Dynamic regulation of Nanog and stem cell-signaling pathways by Hoxa1 during early neuro-ectodermal differentiation of ES cells. Proc Natl Acad Sci U S A 2018; 114:5838-5845. [PMID: 28584089 DOI: 10.1073/pnas.1610612114] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Homeobox a1 (Hoxa1) is one of the most rapidly induced genes in ES cell differentiation and it is the earliest expressed Hox gene in the mouse embryo. In this study, we used genomic approaches to identify Hoxa1-bound regions during early stages of ES cell differentiation into the neuro-ectoderm. Within 2 h of retinoic acid treatment, Hoxa1 is rapidly recruited to target sites that are associated with genes involved in regulation of pluripotency, and these genes display early changes in expression. The pattern of occupancy of Hoxa1 is dynamic and changes over time. At 12 h of differentiation, many sites bound at 2 h are lost and a new cohort of bound regions appears. At both time points the genome-wide mapping reveals that there is significant co-occupancy of Nanog (Nanog homeobox) and Hoxa1 on many common target sites, and these are linked to genes in the pluripotential regulatory network. In addition to shared target genes, Hoxa1 binds to regulatory regions of Nanog, and conversely Nanog binds to a 3' enhancer of Hoxa1 This finding provides evidence for direct cross-regulatory feedback between Hoxa1 and Nanog through a mechanism of mutual repression. Hoxa1 also binds to regulatory regions of Sox2 (sex-determining region Y box 2), Esrrb (estrogen-related receptor beta), and Myc, which underscores its key input into core components of the pluripotential regulatory network. We propose a model whereby direct inputs of Nanog and Hoxa1 on shared targets and mutual repression between Hoxa1 and the core pluripotency network provides a molecular mechanism that modulates the fine balance between the alternate states of pluripotency and differentiation.
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5
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Lizen B, Moens C, Mouheiche J, Sacré T, Ahn MT, Jeannotte L, Salti A, Gofflot F. Conditional Loss of Hoxa5 Function Early after Birth Impacts on Expression of Genes with Synaptic Function. Front Mol Neurosci 2017; 10:369. [PMID: 29187810 PMCID: PMC5695161 DOI: 10.3389/fnmol.2017.00369] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/26/2017] [Indexed: 12/24/2022] Open
Abstract
Hoxa5 is a member of the Hox gene family that plays critical roles in successive steps of the central nervous system formation during embryonic and fetal development. In the mouse, Hoxa5 was recently shown to be expressed in the medulla oblongata and the pons from fetal stages to adulthood. In these territories, Hoxa5 transcripts are enriched in many precerebellar neurons and several nuclei involved in autonomic functions, while the HOXA5 protein is detected mainly in glutamatergic and GABAergic neurons. However, whether HOXA5 is functionally required in these neurons after birth remains unknown. As a first approach to tackle this question, we aimed at determining the molecular programs downstream of the HOXA5 transcription factor in the context of the postnatal brainstem. A comparative transcriptomic analysis was performed in combination with gene expression localization, using a conditional postnatal Hoxa5 loss-of-function mouse model. After inactivation of Hoxa5 at postnatal days (P)1–P4, we established the transcriptome of the brainstem from P21 Hoxa5 conditional mutants using RNA-Seq analysis. One major finding was the downregulation of several genes associated with synaptic function in Hoxa5 mutant specimens including different actors involved in glutamatergic synapse, calcium signaling pathway, and GABAergic synapse. Data were confirmed and extended by reverse transcription quantitative polymerase chain reaction analysis, and the expression of several HOXA5 candidate targets was shown to co-localize with Hoxa5 transcripts in precerebellar nuclei. Together, these new results revealed that HOXA5, through the regulation of key actors of the glutamatergic/GABAergic synapses and calcium signaling, might be involved in synaptogenesis, synaptic transmission, and synaptic plasticity of the cortico-ponto-cerebellar circuitry in the postnatal brainstem.
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Affiliation(s)
- Benoit Lizen
- Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Charlotte Moens
- Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Jinane Mouheiche
- Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Thomas Sacré
- Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Marie-Thérèse Ahn
- Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Lucie Jeannotte
- Department of Molecular Biology, Medical Biochemistry and Pathology, Université Laval, Quebec City, QC, Canada.,Centre de Recherche sur le Cancer, Université Laval, Quebec City, QC, Canada.,Centre de Recherche, Centre Hospitalier Universitaire de Québec, Université Laval, Quebec City, QC, Canada
| | - Ahmad Salti
- Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Françoise Gofflot
- Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium
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6
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ISL1-based LIM complexes control Slit2 transcription in developing cranial motor neurons. Sci Rep 2016; 6:36491. [PMID: 27819291 PMCID: PMC5098159 DOI: 10.1038/srep36491] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/17/2016] [Indexed: 01/02/2023] Open
Abstract
LIM-homeodomain (HD) transcription factors form a multimeric complex and assign neuronal subtype identities, as demonstrated by the hexameric ISL1-LHX3 complex which gives rise to somatic motor (SM) neurons. However, the roles of combinatorial LIM code in motor neuron diversification and their subsequent differentiation is much less well understood. In the present study, we demonstrate that the ISL1 controls postmitotic cranial branchiomotor (BM) neurons including the positioning of the cell bodies and peripheral axon pathfinding. Unlike SM neurons, which transform into interneurons, BM neurons are normal in number and in marker expression in Isl1 mutant mice. Nevertheless, the movement of trigeminal and facial BM somata is stalled, and their peripheral axons are fewer or misrouted, with ectopic branches. Among genes whose expression level changes in previous ChIP-seq and microarray analyses in Isl1-deficient cell lines, we found that Slit2 transcript was almost absent from BM neurons of Isl1 mutants. Both ISL1-LHX3 and ISL1-LHX4 bound to the Slit2 enhancer and drove endogenous Slit2 expression in SM and BM neurons. Our findings suggest that combinations of ISL1 and LHX factors establish cell-type specificity and functional diversity in terms of motor neuron identities and/or axon development.
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7
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Chuang JH, Tung LC, Lin Y. Neural differentiation from embryonic stem cells in vitro: An overview of the signaling pathways. World J Stem Cells 2015; 7:437-447. [PMID: 25815127 PMCID: PMC4369499 DOI: 10.4252/wjsc.v7.i2.437] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/12/2014] [Accepted: 12/17/2014] [Indexed: 02/06/2023] Open
Abstract
Neurons derived from embryonic stem cells (ESCs) have gained great merit in both basic research and regenerative medicine. Here we review and summarize the signaling pathways that have been reported to be involved in the neuronal differentiation of ESCs, particularly those associated with in vitro differentiation. The inducers and pathways explored include retinoic acid, Wnt/β-catenin, transforming growth factor/bone morphogenetic protein, Notch, fibroblast growth factor, cytokine, Hedgehog, c-Jun N-terminal kinase/mitogen-activated protein kinase and others. Some other miscellaneous molecular factors that have been reported in the literature are also summarized and discussed. These include calcium, calcium receptor, calcineurin, estrogen receptor, Hox protein, ceramide, glycosaminioglycan, ginsenoside Rg1, opioids, two pore channel 2, nitric oxide, chemically defined medium, cell-cell interactions, and physical stimuli. The interaction or crosstalk between these signaling pathways and factors will be explored. Elucidating these signals in detail should make a significant contribution to future progress in stem cell biology and allow, for example, better comparisons to be made between differentiation in vivo and in vitro. Of equal importance, a comprehensive understanding of the pathways that are involved in the development of neurons from ESCs in vitro will also accelerate their application as part of translational medicine.
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8
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Willaredt MA, Schlüter T, Nothwang HG. The gene regulatory networks underlying formation of the auditory hindbrain. Cell Mol Life Sci 2015; 72:519-535. [PMID: 25332098 PMCID: PMC11113740 DOI: 10.1007/s00018-014-1759-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/24/2014] [Accepted: 10/09/2014] [Indexed: 01/28/2023]
Abstract
Development and evolution of auditory hindbrain nuclei are two major unsolved issues in hearing research. Recent characterization of transgenic mice identified the rhombomeric origins of mammalian auditory nuclei and unraveled genes involved in their formation. Here, we provide an overview on these data by assembling them into rhombomere-specific gene regulatory networks (GRNs), as they underlie developmental and evolutionary processes. To explore evolutionary mechanisms, we compare the GRNs operating in the mammalian auditory hindbrain with data available from the inner ear and other vertebrate groups. Finally, we propose that the availability of genomic sequences from all major vertebrate taxa and novel genetic techniques for non-model organisms provide an unprecedented opportunity to investigate development and evolution of the auditory hindbrain by comparative molecular approaches. The dissection of the molecular mechanisms leading to auditory structures will also provide an important framework for auditory processing disorders, a clinical problem difficult to tackle so far. These data will, therefore, foster basic and clinical hearing research alike.
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Affiliation(s)
- Marc A Willaredt
- Neurogenetics group, Center of Excellence Hearing4All, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
| | - Tina Schlüter
- Neurogenetics group, Center of Excellence Hearing4All, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany
| | - Hans Gerd Nothwang
- Neurogenetics group, Center of Excellence Hearing4All, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
- Research Center for Neurosensory Science, Carl von Ossietzky University Oldenburg, 26111, Oldenburg, Germany.
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9
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The emerging framework of mammalian auditory hindbrain development. Cell Tissue Res 2015; 361:33-48. [DOI: 10.1007/s00441-014-2110-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 12/22/2014] [Indexed: 02/06/2023]
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10
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Iovino S, Burkart AM, Kriauciunas K, Warren L, Hughes KJ, Molla M, Lee YK, Patti ME, Kahn CR. Genetic insulin resistance is a potent regulator of gene expression and proliferation in human iPS cells. Diabetes 2014; 63:4130-42. [PMID: 25059784 PMCID: PMC4238001 DOI: 10.2337/db14-0109] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Insulin resistance is central to diabetes and metabolic syndrome. To define the consequences of genetic insulin resistance distinct from those secondary to cellular differentiation or in vivo regulation, we generated induced pluripotent stem cells (iPSCs) from individuals with insulin receptor mutations and age-appropriate control subjects and studied insulin signaling and gene expression compared with the fibroblasts from which they were derived. iPSCs from patients with genetic insulin resistance exhibited altered insulin signaling, paralleling that seen in the original fibroblasts. Insulin-stimulated expression of immediate early genes and proliferation were also potently reduced in insulin resistant iPSCs. Global gene expression analysis revealed marked differences in both insulin-resistant iPSCs and corresponding fibroblasts compared with control iPSCs and fibroblasts. Patterns of gene expression in patients with genetic insulin resistance were particularly distinct in the two cell types, indicating dependence on not only receptor activity but also the cellular context of the mutant insulin receptor. Thus, iPSCs provide a novel approach to define effects of genetically determined insulin resistance. This study demonstrates that effects of insulin resistance on gene expression are modified by cellular context and differentiation state. Moreover, altered insulin receptor signaling and insulin resistance can modify proliferation and function of pluripotent stem cell populations.
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Affiliation(s)
- Salvatore Iovino
- Integrative Physiology and Metabolism Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, MA
| | - Alison M Burkart
- Integrative Physiology and Metabolism Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, MA
| | - Kristina Kriauciunas
- Integrative Physiology and Metabolism Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, MA
| | - Laura Warren
- Integrative Physiology and Metabolism Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, MA
| | - Katelyn J Hughes
- Integrative Physiology and Metabolism Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, MA
| | - Michael Molla
- Integrative Physiology and Metabolism Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, MA
| | - Youn-Kyoung Lee
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA
| | - Mary-Elizabeth Patti
- Integrative Physiology and Metabolism Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, MA
| | - C Ronald Kahn
- Integrative Physiology and Metabolism Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, MA
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11
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A Hox gene controls lateral line cell migration by regulating chemokine receptor expression downstream of Wnt signaling. Proc Natl Acad Sci U S A 2013; 110:16892-7. [PMID: 24082091 DOI: 10.1073/pnas.1306282110] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The posterior lateral line primordium in zebrafish provides an amenable model to study mechanisms of collective cell migration. The directed migration of the cell cluster along the path of Sdf1a chemokine requires two receptors, Cxcr4b and Cxcr7b, which are expressed in the leading and trailing part of the primordium, respectively. The polarized expression of receptors is regulated by Wnt signaling, but downstream players mediating this control remain to be found. Here, we show that the Hox homeobox gene Hoxb8a is a critical component that acts downstream of the Wnt pathway to coordinate the expression of both chemokine receptors. We find that Hoxb8a is expressed in the leading part of the primordium and is required for the correct speed and extent of migration. Hoxb8a expression is dependent upon Wnt activity and needed both for cxcr4b expression and to repress and thus restrict cxcr7b expression to the trailing zone of the primordium. In the absence of Wnt activity, overexpressed Hoxb8a is able to repress cxcr7b but not up-regulate cxcr4b expression. Together with results from expressing dominant activator and repressor constructs, these findings suggest that Hoxb8a is induced by and cooperates with Wnt signaling to up-regulate cxcr4b, and acts through multiple mechanisms to repress cxcr7b expression.
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