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Somaiya RD, Stebbins K, Gingrich EC, Xie H, Campbell JN, Garcia ADR, Fox MA. Sonic hedgehog-dependent recruitment of GABAergic interneurons into the developing visual thalamus. eLife 2022; 11:e79833. [PMID: 36342840 PMCID: PMC9640189 DOI: 10.7554/elife.79833] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 10/10/2022] [Indexed: 11/09/2022] Open
Abstract
Axons of retinal ganglion cells (RGCs) play critical roles in the development of inhibitory circuits in visual thalamus. We previously reported that RGC axons signal astrocytes to induce the expression of fibroblast growth factor 15 (FGF15), a motogen required for GABAergic interneuron migration into visual thalamus. However, how retinal axons induce thalamic astrocytes to generate Fgf15 and influence interneuron migration remains unknown. Here, we demonstrate that impairing RGC activity had little impact on interneuron recruitment into mouse visual thalamus. Instead, our data show that retinal-derived sonic hedgehog (SHH) is essential for interneuron recruitment. Specifically, we show that thalamus-projecting RGCs express SHH and thalamic astrocytes generate downstream components of SHH signaling. Deletion of RGC-derived SHH leads to a significant decrease in Fgf15 expression, as well as in the percentage of interneurons recruited into visual thalamus. Overall, our findings identify a morphogen-dependent neuron-astrocyte signaling mechanism essential for the migration of thalamic interneurons.
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Affiliation(s)
- Rachana Deven Somaiya
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech CarilionRoanokeUnited States
- Graduate Program in Translational Biology, Medicine, and Health, Virginia TechBlacksburgUnited States
| | - Katelyn Stebbins
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech CarilionRoanokeUnited States
- Graduate Program in Translational Biology, Medicine, and Health, Virginia TechBlacksburgUnited States
- Virginia Tech Carilion School of MedicineRoanokeUnited States
| | - Ellen C Gingrich
- Department of Biology, Drexel UniversityPhiladelphiaUnited States
- Department of Neurobiology and Anatomy, Drexel University College of MedicinePhiladelphiaUnited States
| | - Hehuang Xie
- Fralin Life Sciences Institute at Virginia TechBlacksburgUnited States
- School of Neuroscience, College of Science, Virginia TechBlacksburgUnited States
- Genetics, Bioinformatics and Computational Biology Program, Virginia TechBlacksburgUnited States
- Department of Biomedical Sciences and Pathobiology, Virginia–Maryland College of Veterinary MedicineBlacksburgUnited States
| | - John N Campbell
- Department of Biology, University of VirginiaCharlottesvilleUnited States
- Neuroscience Graduate Program, University of VirginiaCharlottesvilleUnited States
| | - A Denise R Garcia
- Department of Biology, Drexel UniversityPhiladelphiaUnited States
- Department of Neurobiology and Anatomy, Drexel University College of MedicinePhiladelphiaUnited States
| | - Michael A Fox
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech CarilionRoanokeUnited States
- School of Neuroscience, College of Science, Virginia TechBlacksburgUnited States
- Department of Biological Sciences, College of Science, Virginia TechBlacksburgUnited States
- Department of Pediatrics, Virginia Tech Carilion School of MedicineRoanokeUnited States
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2
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The Neocortical Progenitor Specification Program Is Established through Combined Modulation of SHH and FGF Signaling. J Neurosci 2020; 40:6872-6887. [PMID: 32737167 DOI: 10.1523/jneurosci.2888-19.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 06/22/2020] [Accepted: 07/18/2020] [Indexed: 12/21/2022] Open
Abstract
Neuronal progenitors in the developing forebrain undergo dynamic competence states to ensure timely generation of specific excitatory and inhibitory neuronal subtypes from distinct neurogenic niches of the dorsal and ventral forebrain, respectively. Here we show evidence of progenitor plasticity when Sonic hedgehog (SHH) signaling is left unmodulated in the embryonic neocortex of the mammalian dorsal forebrain. We found that, at early stages of corticogenesis, loss of Suppressor of Fused (Sufu), a potent inhibitor of SHH signaling, in neocortical progenitors, altered the transcriptomic landscape of male mouse embryos. Ectopic activation of SHH signaling occurred, via degradation of Gli3R, resulting in significant upregulation of fibroblast growth factor 15 (FGF15) gene expression in all E12.5 Sufu-cKO neocortex regardless of sex. Consequently, activation of FGF signaling, and its downstream effector the MAPK signaling, facilitated expression of genes characteristic of ventral forebrain progenitors. Our studies identify the importance of modulating extrinsic niche signals such as SHH and FGF15, to maintain the competency and specification program of neocortical progenitors throughout corticogenesis.SIGNIFICANCE STATEMENT Low levels of FGF15 control progenitor proliferation and differentiation during neocortical development, but little is known on how FGF15 expression is maintained. Our studies identified SHH signaling as a critical activator of FGF15 expression during corticogenesis. We found that Sufu, via Gli3R, ensured low levels of FGF15 was expressed to prevent abnormal specification of neocortical progenitors. These studies advance our knowledge on the molecular mechanisms guiding the generation of specific neocortical neuronal lineages, their implications in neurodevelopmental diseases, and may guide future studies on how progenitor cells may be used for brain repair.
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Sirkisoon SR, Carpenter RL, Rimkus T, Doheny D, Zhu D, Aguayo NR, Xing F, Chan M, Ruiz J, Metheny-Barlow LJ, Strowd R, Lin J, Regua AT, Arrigo A, Anguelov M, Pasche B, Debinski W, Watabe K, Lo HW. TGLI1 transcription factor mediates breast cancer brain metastasis via activating metastasis-initiating cancer stem cells and astrocytes in the tumor microenvironment. Oncogene 2019; 39:64-78. [PMID: 31462709 PMCID: PMC6938539 DOI: 10.1038/s41388-019-0959-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 06/24/2019] [Accepted: 07/25/2019] [Indexed: 11/24/2022]
Abstract
Mechanisms for breast cancer metastasis remain unclear. Whether truncated glioma-associated oncogene homolog 1 (TGLI1), a transcription factor known to promote angiogenesis, migration and invasion, plays any role in metastasis of any tumor type has never been investigated. In this study, results of two mouse models of breast cancer metastasis showed that ectopic expression of TGLI1, but not GLI1, promoted preferential metastasis to the brain. Conversely, selective TGLI1 knockdown using antisense oligonucleotides led to decreased breast cancer brain metastasis (BCBM) in vivo. Immunohistochemical staining showed that TGLI1, but not GLI1, was increased in lymph node metastases compared to matched primary tumors, and that TGLI1 was expressed at higher levels in BCBM specimens compared to primary tumors. TGLI1 activation is associated with a shortened time to develop BCBM and enriched in HER2-enriched and triple-negative breast cancers. Radioresistant BCBM cell lines and specimens expressed higher levels of TGLI1, but not GLI1, than radiosensitive counterparts. Since cancer stem cells (CSCs) are radioresistant and metastasis-initiating cells, we examined TGLI1 for its involvement in breast CSCs and found TGLI1 to transcriptionally activate stemness genes CD44, Nanog, Sox2, and OCT4 leading to CSC renewal, and TGLI1 outcompetes with GLI1 for binding to target promoters. We next examined whether astrocyte-priming underlies TGLI1-mediated brain tropism and found that TGLI1-positive CSCs strongly activated and interacted with astrocytes in vitro and in vivo. These findings demonstrate, for the first time, that TGLI1 mediates breast cancer metastasis to the brain, in part, through promoting metastasis-initiating CSCs and activating astrocytes in BCBM microenvironment.
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Affiliation(s)
- Sherona R Sirkisoon
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Richard L Carpenter
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.,Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Bloomington, IN, USA
| | - Tadas Rimkus
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Daniel Doheny
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Dongqin Zhu
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Noah R Aguayo
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Fei Xing
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.,Comprehensive Cancer Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Michael Chan
- Comprehensive Cancer Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA.,Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Jimmy Ruiz
- Comprehensive Cancer Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA.,Department of Hematology and Oncology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Linda J Metheny-Barlow
- Comprehensive Cancer Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA.,Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Roy Strowd
- Comprehensive Cancer Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA.,Department of Neurology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Jiayuh Lin
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Angelina T Regua
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Austin Arrigo
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Marlyn Anguelov
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Boris Pasche
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.,Comprehensive Cancer Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Waldemar Debinski
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.,Comprehensive Cancer Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Kounosuke Watabe
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.,Comprehensive Cancer Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Hui-Wen Lo
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, USA. .,Comprehensive Cancer Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
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Somm E, Jornayvaz FR. Fibroblast Growth Factor 15/19: From Basic Functions to Therapeutic Perspectives. Endocr Rev 2018; 39:960-989. [PMID: 30124818 DOI: 10.1210/er.2018-00134] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/10/2018] [Indexed: 12/11/2022]
Abstract
Discovered 20 years ago, fibroblast growth factor (FGF)19, and its mouse ortholog FGF15, were the first members of a new subfamily of FGFs able to act as hormones. During fetal life, FGF15/19 is involved in organogenesis, affecting the development of the ear, eye, heart, and brain. At adulthood, FGF15/19 is mainly produced by the ileum, acting on the liver to repress hepatic bile acid synthesis and promote postprandial nutrient partitioning. In rodents, pharmacologic doses of FGF19 induce the same antiobesity and antidiabetic actions as FGF21, with these metabolic effects being partly mediated by the brain. However, activation of hepatocyte proliferation by FGF19 has long been a challenge to its therapeutic use. Recently, genetic reengineering of the molecule has resolved this issue. Despite a global overlap in expression pattern and function, murine FGF15 and human FGF19 exhibit several differences in terms of regulation, molecular structure, signaling, and biological properties. As most of the knowledge originates from the use of FGF19 in murine models, differences between mice and humans in the biology of FGF15/19 have to be considered for a successful translation from bench to bedside. This review summarizes the basic knowledge concerning FGF15/19 in mice and humans, with a special focus on regulation of production, morphogenic properties, hepatocyte growth, bile acid homeostasis, as well as actions on glucose, lipid, and energy homeostasis. Moreover, implications and therapeutic perspectives concerning FGF19 in human diseases (including obesity, type 2 diabetes, hepatic steatosis, biliary disorders, and cancer) are also discussed.
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Affiliation(s)
- Emmanuel Somm
- Service of Endocrinology, Diabetes, Hypertension, and Nutrition, Geneva University Hospitals, University of Geneva Medical School, Geneva, Switzerland
| | - François R Jornayvaz
- Service of Endocrinology, Diabetes, Hypertension, and Nutrition, Geneva University Hospitals, University of Geneva Medical School, Geneva, Switzerland
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McNeill B, Perez-Iratxeta C, Mazerolle C, Furimsky M, Mishina Y, Andrade-Navarro MA, Wallace VA. Comparative genomics identification of a novel set of temporally regulated hedgehog target genes in the retina. Mol Cell Neurosci 2012; 49:333-40. [PMID: 22281533 DOI: 10.1016/j.mcn.2011.12.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 11/07/2011] [Accepted: 12/15/2011] [Indexed: 11/26/2022] Open
Abstract
The hedgehog (Hh) signaling pathway is involved in numerous developmental and adult processes with many links to cancer. In vertebrates, the activity of the Hh pathway is mediated primarily through three Gli transcription factors (Gli1, 2 and 3) that can serve as transcriptional activators or repressors. The identification of Gli target genes is essential for the understanding of the Hh-mediated processes. We used a comparative genomics approach using the mouse and human genomes to identify 390 genes that contained conserved Gli binding sites. RT-qPCR validation of 46 target genes in E14.5 and P0.5 retinal explants revealed that Hh pathway activation resulted in the modulation of 30 of these targets, 25 of which demonstrated a temporal regulation. Further validation revealed that the expression of Bok, FoxA1, Sox8 and Wnt7a was dependent upon Sonic Hh (Shh) signaling in the retina and their regulation is under positive and negative controls by Gli2 and Gli3, respectively. We also show using chromatin immunoprecipitation that Gli2 binds to the Sox8 promoter, suggesting that Sox8 is an Hh-dependent direct target of Gli2. Finally, we demonstrate that the Hh pathway also modulates the expression of Sox9 and Sox10, which together with Sox8 make up the SoxE group. Previously, it has been shown that Hh and SoxE group genes promote Müller glial cell development in the retina. Our data are consistent with the possibility for a role of SoxE group genes downstream of Hh signaling on Müller cell development.
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Affiliation(s)
- Brian McNeill
- Vision Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario, Canada K1H 8L6
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White MA, Parker DS, Barolo S, Cohen BA. A model of spatially restricted transcription in opposing gradients of activators and repressors. Mol Syst Biol 2012; 8:614. [PMID: 23010997 PMCID: PMC3472688 DOI: 10.1038/msb.2012.48] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 08/20/2012] [Indexed: 12/24/2022] Open
Abstract
Morphogens control patterns of transcription in development, often by establishing concentration gradients of a single transcriptional activator. However, many morphogens, including Hedgehog, create opposing activator and repressor gradients (OARGs). In contrast to single activator gradients, it is not well understood how OARGs control transcriptional patterns. We present a general thermodynamic model that explains how spatial patterns of gene expression are established within OARGs. The model predicts that differences in enhancer binding site affinities for morphogen-responsive transcription factors (TFs) produce discrete transcriptional boundaries, but only when either activators or repressors bind cooperatively. This model quantitatively predicts the boundaries of gene expression within OARGs. When trained on experimental data, our model accounts for the counterintuitive observation that increasing the affinity of binding sites in enhancers of Hedgehog target genes produces more restricted transcription within Hedgehog gradients in Drosophila. Because our model is general, it may explain the role of low-affinity binding sites in many contexts, including mammalian Hedgehog gradients.
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Affiliation(s)
- Michael A White
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St Louis, MO, USA
| | - Davis S Parker
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Scott Barolo
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Barak A Cohen
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St Louis, MO, USA
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Porntaveetus T, Otsuka-Tanaka Y, Basson MA, Moon AM, Sharpe PT, Ohazama A. Expression of fibroblast growth factors (Fgfs) in murine tooth development. J Anat 2011; 218:534-43. [PMID: 21332717 DOI: 10.1111/j.1469-7580.2011.01352.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Fgf signalling is known to play critical roles in tooth development. Twenty-two Fgf ligands have been identified in mammals, but expression of only 10 in molars and three in the incisor loop stem cell region have been documented in murine tooth development. Our understanding of Fgf signalling in tooth development thus remains incomplete and we therefore carried out comparative in situ hybridisation analysis of unexamined Fgf ligands (eight in molars and 15 in cervical loops of incisors; Fgf11-Fgf14 were excluded from this analysis because they are not secreted and do not activate Fgf receptors) during tooth development. To identify where Fgf signalling is activated, we also examined the expression of Etv4 and Etv5, considered to be transcriptional targets of the Fgf signalling pathway. In molar tooth development, the expression of Fgf15 and Fgf20 was restricted to the primary enamel knots, whereas Etv4 and Etv5 were expressed in cells surrounding the primary enamel knots. Fgf20 expression was observed in the secondary enamel knots, whereas Fgf15 showed localised expression in the adjacent mesenchyme. Fgf16, Etv4 and Etv5 were strongly expressed in the ameloblasts of molars. In the incisor cervical loop stem cell region, Fgf17, Fgf18, Etv4 and Etv5 showed a restricted expression pattern. These molecules thus show dynamic temporo-spatial expression in murine tooth development. We also analysed teeth in Fgf15(-/-) and Fgf15(-/-) ;Fgf8(+/-) mutant mice. Neither mutant showed significant abnormalities in tooth development, indicating likely functional redundancy.
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Affiliation(s)
- Thantrira Porntaveetus
- Department of Craniofacial Development, Dental Institute, King's College London, Guy's Hospital, London, UK
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Winklmayr M, Schmid C, Laner-Plamberger S, Kaser A, Aberger F, Eichberger T, Frischauf AM. Non-consensus GLI binding sites in Hedgehog target gene regulation. BMC Mol Biol 2010; 11:2. [PMID: 20070907 PMCID: PMC2830928 DOI: 10.1186/1471-2199-11-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Accepted: 01/13/2010] [Indexed: 01/22/2023] Open
Abstract
Background The GLI transcription factors, mediators of the hedgehog signal bind with high affinity to the consensus sequence GACCACCCA. The affinity of variant single substitutions in GLI binding sites has been measured systematically, but the affinities of the variant binding sites appears low compared to the frequency of occurrence of variant sites in known GLI target gene promoters. Results We quantified transcriptional activation by GLI using PTCH1 promoter based luciferase reporters containing all single substitutions of the GLI consensus binding site. As expected variants with very low affinity did not activate the reporter. Many lower affinity binding sequences are, however, functional in the presence of moderate GLI concentration. Using two natural non-consensus GLI site promoters we showed that substitution of the variant sequences by consensus leads to comparable activity. Conclusions Variant GLI binding sites with relatively low affinity can within natural promoters lead to strong transcriptional activation. This may facilitate the identification of additional direct GLI target genes.
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Affiliation(s)
- Martina Winklmayr
- Department of Molecular Biology, University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria
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