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Vilas A, Briso-Montiano Á, Segovia-Falquina C, Martín-Martínez A, Soriano-Sexto A, Gallego D, Ruiz-Montés V, Gámez A, Pérez B. HepG2 PMM2-CDG knockout model: A versatile platform for variant and therapeutic evaluation. Mol Genet Metab 2024; 143:108538. [PMID: 39096554 DOI: 10.1016/j.ymgme.2024.108538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 06/28/2024] [Accepted: 07/15/2024] [Indexed: 08/05/2024]
Abstract
Phosphomannomutase 2 deficiency (PMM2-CDG), the most frequent congenital disorder of glycosylation, is an autosomal recessive disease caused by biallelic pathogenic variants in the PMM2 gene. There is no cure for this multisystemic syndrome. Some of the therapeutic approaches that are currently in development include mannose-1-phosphate replacement therapy, drug repurposing, and the use of small chemical molecules to correct folding defects. Preclinical models are needed to evaluate the efficacy of treatments to overcome the high lethality of the available animal model. In addition, the number of variants with unknown significance is increasing in clinical settings. This study presents the generation of a cellular disease model by knocking out the PMM2 gene in the hepatoma HepG2 cell line using CRISPR-Cas9 gene editing. The HepG2 knockout model accurately replicates the PMM2-CDG phenotype, exhibiting a complete absence of PMM2 protein and mRNA, a 90% decrease in PMM enzymatic activity, and altered ICAM-1, LAMP1 and A1AT glycoprotein patterns. The evaluation of PMM2 disease-causing variants validates the model's utility for studying new PMM2 clinical variants, providing insights for diagnosis and potentially for evaluating therapies. A CRISPR-Cas9-generated HepG2 knockout model accurately recapitulates the PMM2-CDG phenotype, providing a valuable tool for assessing disease-causing variants and advancing therapeutic strategies.
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Affiliation(s)
- Alicia Vilas
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain; U746 - CIBER de Enfermedades Raras (CIBERER), Madrid, Spain; Instituto de Investigación Sanitaria IdiPAZ, Madrid, Spain
| | - Álvaro Briso-Montiano
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain; U746 - CIBER de Enfermedades Raras (CIBERER), Madrid, Spain; Instituto de Investigación Sanitaria IdiPAZ, Madrid, Spain
| | - Cristina Segovia-Falquina
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain; U746 - CIBER de Enfermedades Raras (CIBERER), Madrid, Spain; Instituto de Investigación Sanitaria IdiPAZ, Madrid, Spain
| | - Arturo Martín-Martínez
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain; U746 - CIBER de Enfermedades Raras (CIBERER), Madrid, Spain; Instituto de Investigación Sanitaria IdiPAZ, Madrid, Spain
| | - Alejandro Soriano-Sexto
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain; U746 - CIBER de Enfermedades Raras (CIBERER), Madrid, Spain; Instituto de Investigación Sanitaria IdiPAZ, Madrid, Spain
| | - Diana Gallego
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain; U746 - CIBER de Enfermedades Raras (CIBERER), Madrid, Spain; Instituto de Investigación Sanitaria IdiPAZ, Madrid, Spain
| | - Vera Ruiz-Montés
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain; U746 - CIBER de Enfermedades Raras (CIBERER), Madrid, Spain; Instituto de Investigación Sanitaria IdiPAZ, Madrid, Spain
| | - Alejandra Gámez
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain; U746 - CIBER de Enfermedades Raras (CIBERER), Madrid, Spain; Instituto de Investigación Sanitaria IdiPAZ, Madrid, Spain
| | - Belén Pérez
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-SO UAM-CSIC, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain; U746 - CIBER de Enfermedades Raras (CIBERER), Madrid, Spain; Instituto de Investigación Sanitaria IdiPAZ, Madrid, Spain.
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Annibalini G, Di Patria L, Valli G, Bocconcelli M, Saltarelli R, Ferri L, Barberi L, Fanelli F, Morrone A, Barone R, Guerrini R, Musarò A, Stocchi V, Barbieri E. Impaired myoblast differentiation and muscle IGF-1 receptor signaling pathway activation after N-glycosylation inhibition. FASEB J 2024; 38:e23797. [PMID: 38963344 DOI: 10.1096/fj.202400213rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 06/08/2024] [Accepted: 06/24/2024] [Indexed: 07/05/2024]
Abstract
The role of N-glycosylation in the myogenic process remains poorly understood. Here, we evaluated the impact of N-glycosylation inhibition by Tunicamycin (TUN) or by phosphomannomutase 2 (PMM2) gene knockdown, which encodes an enzyme essential for catalyzing an early step of the N-glycosylation pathway, on C2C12 myoblast differentiation. The effect of chronic treatment with TUN on tibialis anterior (TA) and extensor digitorum longus (EDL) muscles of WT and MLC/mIgf-1 transgenic mice, which overexpress muscle Igf-1Ea mRNA isoform, was also investigated. TUN-treated and PMM2 knockdown C2C12 cells showed reduced ConA, PHA-L, and AAL lectin binding and increased ER-stress-related gene expression (Chop and Hspa5 mRNAs and s/uXbp1 ratio) compared to controls. Myogenic markers (MyoD, myogenin, and Mrf4 mRNAs and MF20 protein) and myotube formation were reduced in both TUN-treated and PMM2 knockdown C2C12 cells. Body and TA weight of WT and MLC/mIgf-1 mice were not modified by TUN treatment, while lectin binding slightly decreased in the TA muscle of WT (ConA and AAL) and MLC/mIgf-1 (ConA) mice. The ER-stress-related gene expression did not change in the TA muscle of WT and MLC/mIgf-1 mice after TUN treatment. TUN treatment decreased myogenin mRNA and increased atrogen-1 mRNA, particularly in the TA muscle of WT mice. Finally, the IGF-1 production and IGF1R signaling pathways activation were reduced due to N-glycosylation inhibition in TA and EDL muscles. Decreased IGF1R expression was found in TUN-treated C2C12 myoblasts which was associated with lower IGF-1-induced IGF1R, AKT, and ERK1/2 phosphorylation compared to CTR cells. Chronic TUN-challenge models can help to elucidate the molecular mechanisms through which diseases associated with aberrant N-glycosylation, such as Congenital Disorders of Glycosylation (CDG), affect muscle and other tissue functions.
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Affiliation(s)
- Giosuè Annibalini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Laura Di Patria
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Giacomo Valli
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Matteo Bocconcelli
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Roberta Saltarelli
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Lorenzo Ferri
- Department of Neuroscience and Medical Genetics, Meyer Children's Hospital IRCCS, Florence, Italy
| | - Laura Barberi
- DAHFMO-Unit of Histology and Medical Embryology, Laboratory Affiliated to Istituto Pasteur Italia, University of Rome La Sapienza, Rome, Italy
| | - Fabiana Fanelli
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Amelia Morrone
- Department of Neuroscience and Medical Genetics, Meyer Children's Hospital IRCCS, Florence, Italy
- Department of NEUROFARBA, University of Florence, Florence, Italy
| | - Rita Barone
- Child Neurology and Psychiatry Unit, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
- Research Unit of Rare Diseases and Neurodevelopmental Disorders, Oasi Research Institute-IRCCS, Troina, Italy
| | - Renzo Guerrini
- Department of Neuroscience and Medical Genetics, Meyer Children's Hospital IRCCS, Florence, Italy
- Department of NEUROFARBA, University of Florence, Florence, Italy
| | - Antonio Musarò
- DAHFMO-Unit of Histology and Medical Embryology, Laboratory Affiliated to Istituto Pasteur Italia, University of Rome La Sapienza, Rome, Italy
| | - Vilberto Stocchi
- Department of Human Sciences for the Promotion of Quality of Life, University San Raffaele, Rome, Italy
| | - Elena Barbieri
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
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3
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Aziz RA, Ramesh P, Suchithra KV, Stothard P, Narayana VK, Raghu SV, Shen FT, Young CC, Prasad TSK, Hameed A. Comprehensive insights into the impact of bacterial indole-3-acetic acid on sensory preferences in Drosophila melanogaster. Sci Rep 2024; 14:8311. [PMID: 38594449 PMCID: PMC11003987 DOI: 10.1038/s41598-024-58829-7] [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: 12/05/2023] [Accepted: 04/03/2024] [Indexed: 04/11/2024] Open
Abstract
Several bacteria of environmental and clinical origins, including some human-associated strains secrete a cross-kingdom signaling molecule indole-3-acetic acid (IAA). IAA is a tryptophan (trp) derivative mainly known for regulating plant growth and development as a hormone. However, the nutritional sources that boost IAA secretion in bacteria and the impact of secreted IAA on non-plant eukaryotic hosts remained less explored. Here, we demonstrate significant trp-dependent IAA production in Pseudomonas juntendi NEEL19 when provided with ethanol as a carbon source in liquid cultures. IAA was further characterized to modulate the odor discrimination, motility and survivability in Drosophila melanogaster. A detailed analysis of IAA-fed fly brain proteome using high-resolution mass spectrometry showed significant (fold change, ± 2; p ≤ 0.05) alteration in the proteins governing neuromuscular features, audio-visual perception and energy metabolism as compared to IAA-unfed controls. Sex-wise variations in differentially regulated proteins were witnessed despite having similar visible changes in chemo perception and psychomotor responses in IAA-fed flies. This study not only revealed ethanol-specific enhancement in trp-dependent IAA production in P. juntendi, but also showed marked behavioral alterations in flies for which variations in an array of proteins governing odor discrimination, psychomotor responses, and energy metabolism are held responsible. Our study provided novel insights into disruptive attributes of bacterial IAA that can potentially influence the eukaryotic gut-brain axis having broad environmental and clinical implications.
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Affiliation(s)
- Raifa Abdul Aziz
- Neurogenetics Lab, Department of Applied Zoology, Mangalore University, Mangalagangothri, Konaje, Mangalore, 574199, India
| | - Poornima Ramesh
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Deralakatte, Mangalore, 575018, India
| | - Kokkarambath Vannadil Suchithra
- Division of Microbiology and Biotechnology, Yenepoya Research Centre, Yenepoya (Deemed to Be University), Deralakatte, Mangalore, 575018, India
| | - Paul Stothard
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
| | - Vanya Kadla Narayana
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Deralakatte, Mangalore, 575018, India
| | - Shamprasad Varija Raghu
- Neurogenetics Lab, Department of Applied Zoology, Mangalore University, Mangalagangothri, Konaje, Mangalore, 574199, India
- Division of Neuroscience, Yenepoya Research Centre, Yenepoya (Deemed to Be University), Deralakatte, Mangalore, 575018, India
| | - Fo-Ting Shen
- Department of Soil & Environmental Sciences, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung, 402, Taiwan.
- Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung, 402, Taiwan.
| | - Chiu-Chung Young
- Department of Soil & Environmental Sciences, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung, 402, Taiwan
- Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung, 402, Taiwan
| | - T S Keshava Prasad
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Deralakatte, Mangalore, 575018, India.
| | - Asif Hameed
- Division of Microbiology and Biotechnology, Yenepoya Research Centre, Yenepoya (Deemed to Be University), Deralakatte, Mangalore, 575018, India.
- Department of Soil & Environmental Sciences, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung, 402, Taiwan.
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4
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Xu C, Xu J, Tang HW, Ericsson M, Weng JH, DiRusso J, Hu Y, Ma W, Asara JM, Perrimon N. A phosphate-sensing organelle regulates phosphate and tissue homeostasis. Nature 2023; 617:798-806. [PMID: 37138087 PMCID: PMC10443203 DOI: 10.1038/s41586-023-06039-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 03/31/2023] [Indexed: 05/05/2023]
Abstract
Inorganic phosphate (Pi) is one of the essential molecules for life. However, little is known about intracellular Pi metabolism and signalling in animal tissues1. Following the observation that chronic Pi starvation causes hyperproliferation in the digestive epithelium of Drosophila melanogaster, we determined that Pi starvation triggers the downregulation of the Pi transporter PXo. In line with Pi starvation, PXo deficiency caused midgut hyperproliferation. Interestingly, immunostaining and ultrastructural analyses showed that PXo specifically marks non-canonical multilamellar organelles (PXo bodies). Further, by Pi imaging with a Förster resonance energy transfer (FRET)-based Pi sensor2, we found that PXo restricts cytosolic Pi levels. PXo bodies require PXo for biogenesis and undergo degradation following Pi starvation. Proteomic and lipidomic characterization of PXo bodies unveiled their distinct feature as an intracellular Pi reserve. Therefore, Pi starvation triggers PXo downregulation and PXo body degradation as a compensatory mechanism to increase cytosolic Pi. Finally, we identified connector of kinase to AP-1 (Cka), a component of the STRIPAK complex and JNK signalling3, as the mediator of PXo knockdown- or Pi starvation-induced hyperproliferation. Altogether, our study uncovers PXo bodies as a critical regulator of cytosolic Pi levels and identifies a Pi-dependent PXo-Cka-JNK signalling cascade controlling tissue homeostasis.
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Affiliation(s)
- Chiwei Xu
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
- Robin Chemers Neustein Laboratory of Mammalian Development and Cell Biology, The Rockefeller University, New York, NY, USA.
| | - Jun Xu
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Hong-Wen Tang
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore, Singapore
| | - Maria Ericsson
- Department of Cell Biology, Electron Microscopy Facility, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Jui-Hsia Weng
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Jonathan DiRusso
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Yanhui Hu
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Wenzhe Ma
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
| | - John M Asara
- Department of Medicine, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
- Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA.
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Sechi S, Karimpour-Ghahnavieh A, Frappaolo A, Di Francesco L, Piergentili R, Schininà E, D’Avino PP, Giansanti MG. Identification of GOLPH3 Partners in Drosophila Unveils Potential Novel Roles in Tumorigenesis and Neural Disorders. Cells 2021; 10:cells10092336. [PMID: 34571985 PMCID: PMC8468827 DOI: 10.3390/cells10092336] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 12/28/2022] Open
Abstract
Golgi phosphoprotein 3 (GOLPH3) is a highly conserved peripheral membrane protein localized to the Golgi apparatus and the cytosol. GOLPH3 binding to Golgi membranes depends on phosphatidylinositol 4-phosphate [PI(4)P] and regulates Golgi architecture and vesicle trafficking. GOLPH3 overexpression has been correlated with poor prognosis in several cancers, but the molecular mechanisms that link GOLPH3 to malignant transformation are poorly understood. We recently showed that PI(4)P-GOLPH3 couples membrane trafficking with contractile ring assembly during cytokinesis in dividing Drosophila spermatocytes. Here, we use affinity purification coupled with mass spectrometry (AP-MS) to identify the protein-protein interaction network (interactome) of Drosophila GOLPH3 in testes. Analysis of the GOLPH3 interactome revealed enrichment for proteins involved in vesicle-mediated trafficking, cell proliferation and cytoskeleton dynamics. In particular, we found that dGOLPH3 interacts with the Drosophila orthologs of Fragile X mental retardation protein and Ataxin-2, suggesting a potential role in the pathophysiology of disorders of the nervous system. Our findings suggest novel molecular targets associated with GOLPH3 that might be relevant for therapeutic intervention in cancers and other human diseases.
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Affiliation(s)
- Stefano Sechi
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Angela Karimpour-Ghahnavieh
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Anna Frappaolo
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Laura Di Francesco
- Dipartimento di Scienze Biochimiche A. Rossi Fanelli, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (L.D.F.); (E.S.)
| | - Roberto Piergentili
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Eugenia Schininà
- Dipartimento di Scienze Biochimiche A. Rossi Fanelli, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (L.D.F.); (E.S.)
| | - Pier Paolo D’Avino
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK;
| | - Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
- Correspondence: ; Tel.: +39-064-991-2555
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Bhimreddy M, Rushton E, Kopke DL, Broadie K. Secreted C-type lectin regulation of neuromuscular junction synaptic vesicle dynamics modulates coordinated movement. J Cell Sci 2021; 134:261954. [PMID: 33973638 DOI: 10.1242/jcs.257592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 04/03/2021] [Indexed: 11/20/2022] Open
Abstract
The synaptic cleft manifests enriched glycosylation, with structured glycans coordinating signaling between presynaptic and postsynaptic cells. Glycosylated signaling ligands orchestrating communication are tightly regulated by secreted glycan-binding lectins. Using the Drosophila neuromuscular junction (NMJ) as a model glutamatergic synapse, we identify a new Ca2+-binding (C-type) lectin, Lectin-galC1 (LGC1), which modulates presynaptic function and neurotransmission strength. We find that LGC1 is enriched in motoneuron presynaptic boutons and secreted into the NMJ extracellular synaptomatrix. We show that LGC1 limits locomotor peristalsis and coordinated movement speed, with a specific requirement for synaptic function, but not NMJ architecture. LGC1 controls neurotransmission strength by limiting presynaptic active zone (AZ) and postsynaptic glutamate receptor (GluR) aligned synapse number, reducing both spontaneous and stimulation-evoked synaptic vesicle (SV) release, and capping SV cycling rate. During high-frequency stimulation (HFS), mutants have faster synaptic depression and impaired recovery while replenishing depleted SV pools. Although LGC1 removal increases the number of glutamatergic synapses, we find that LGC1-null mutants exhibit decreased SV density within presynaptic boutons, particularly SV pools at presynaptic active zones. Thus, LGC1 regulates NMJ neurotransmission to modulate coordinated movement.
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Affiliation(s)
- Meghana Bhimreddy
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - Emma Rushton
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - Danielle L Kopke
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA.,Kennedy Center for Research on Human Development, Vanderbilt University and Medical Center, Nashville, TN 37235, USA.,Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
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7
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Rushton E, Kopke DL, Broadie K. Extracellular heparan sulfate proteoglycans and glycan-binding lectins orchestrate trans-synaptic signaling. J Cell Sci 2020; 133:133/15/jcs244186. [PMID: 32788209 DOI: 10.1242/jcs.244186] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The exceedingly narrow synaptic cleft (<20 nm) and adjacent perisynaptic extracellular space contain an astonishing array of secreted and membrane-anchored glycoproteins. A number of these extracellular molecules regulate intercellular trans-synaptic signaling by binding to ligands, acting as co-receptors or modulating ligand-receptor interactions. Recent work has greatly expanded our understanding of extracellular proteoglycan and glycan-binding lectin families as key regulators of intercellular signaling at the synapse. These secreted proteins act to regulate the compartmentalization of glycoprotein ligands and receptors, crosslink dynamic extracellular and cell surface lattices, modulate both exocytosis and endocytosis vesicle cycling, and control postsynaptic receptor trafficking. Here, we focus closely on the Drosophila glutamatergic neuromuscular junction (NMJ) as a model synapse for understanding extracellular roles of the many heparan sulfate proteoglycan (HSPG) and lectin proteins that help determine synaptic architecture and neurotransmission strength. We particularly concentrate on the roles of extracellular HSPGs and lectins in controlling trans-synaptic signaling, especially that mediated by the Wnt and BMP pathways. These signaling mechanisms are causally linked to a wide spectrum of neurological disease states that impair coordinated movement and cognitive functions.
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Affiliation(s)
- Emma Rushton
- Department of Biological Sciences, Brain Institute, and Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, USA
| | - Danielle L Kopke
- Department of Biological Sciences, Brain Institute, and Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Brain Institute, and Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, USA
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Carrier of Wingless (Cow) Regulation of Drosophila Neuromuscular Junction Development. eNeuro 2020; 7:ENEURO.0285-19.2020. [PMID: 32024666 PMCID: PMC7070448 DOI: 10.1523/eneuro.0285-19.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 01/09/2020] [Accepted: 01/27/2020] [Indexed: 01/17/2023] Open
Abstract
The first Wnt signaling ligand discovered, Drosophila Wingless [Wg (Wnt1 in mammals)], plays critical roles in neuromuscular junction (NMJ) development, regulating synaptic architecture, and function. Heparan sulfate proteoglycans (HSPGs), consisting of a core protein with heparan sulfate (HS) glycosaminoglycan (GAG) chains, bind to Wg ligands to control both extracellular distribution and intercellular signaling function. Drosophila HSPGs previously shown to regulate Wg trans-synaptic signaling at the NMJ include the glypican Dally-like protein (Dlp) and perlecan Terribly Reduced Optic Lobes (Trol). Here, we investigate synaptogenic functions of the most recently described Drosophila HSPG, secreted Carrier of Wingless (Cow), which directly binds Wg in the extracellular space. At the glutamatergic NMJ, we find that Cow secreted from the presynaptic motor neuron acts to limit synaptic architecture and neurotransmission strength. In cow null mutants, we find increased synaptic bouton number and elevated excitatory current amplitudes, phenocopying presynaptic Wg overexpression. We show cow null mutants exhibit an increased number of glutamatergic synapses and increased synaptic vesicle fusion frequency based both on GCaMP imaging and electrophysiology recording. We find that membrane-tethered Wg prevents cow null defects in NMJ development, indicating that Cow mediates secreted Wg signaling. It was shown previously that the secreted Wg deacylase Notum restricts Wg signaling at the NMJ, and we show here that Cow and Notum work through the same pathway to limit synaptic development. We conclude Cow acts cooperatively with Notum to coordinate neuromuscular synapse structural and functional differentiation via negative regulation of Wg trans-synaptic signaling within the extracellular synaptomatrix.
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9
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Large-Scale Transgenic Drosophila Resource Collections for Loss- and Gain-of-Function Studies. Genetics 2020; 214:755-767. [PMID: 32071193 DOI: 10.1534/genetics.119.302964] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 02/11/2020] [Indexed: 01/20/2023] Open
Abstract
The Transgenic RNAi Project (TRiP), a Drosophila melanogaster functional genomics platform at Harvard Medical School, was initiated in 2008 to generate and distribute a genome-scale collection of RNA interference (RNAi) fly stocks. To date, it has generated >15,000 RNAi fly stocks. As this covers most Drosophila genes, we have largely transitioned to development of new resources based on CRISPR technology. Here, we present an update on our libraries of publicly available RNAi and CRISPR fly stocks, and focus on the TRiP-CRISPR overexpression (TRiP-OE) and TRiP-CRISPR knockout (TRiP-KO) collections. TRiP-OE stocks express single guide RNAs targeting upstream of a gene transcription start site. Gene activation is triggered by coexpression of catalytically dead Cas9 fused to an activator domain, either VP64-p65-Rta or Synergistic Activation Mediator. TRiP-KO stocks express one or two single guide RNAs targeting the coding sequence of a gene or genes. Cutting is triggered by coexpression of Cas9, allowing for generation of indels in both germline and somatic tissue. To date, we have generated >5000 TRiP-OE or TRiP-KO stocks for the community. These resources provide versatile, transformative tools for gene activation, gene repression, and genome engineering.
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Functional analysis of glycosylation using Drosophila melanogaster. Glycoconj J 2019; 37:1-14. [DOI: 10.1007/s10719-019-09892-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/13/2019] [Accepted: 09/25/2019] [Indexed: 12/15/2022]
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11
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Iyer S, Sam FS, DiPrimio N, Preston G, Verheijen J, Murthy K, Parton Z, Tsang H, Lao J, Morava E, Perlstein EO. Repurposing the aldose reductase inhibitor and diabetic neuropathy drug epalrestat for the congenital disorder of glycosylation PMM2-CDG. Dis Model Mech 2019; 12:dmm.040584. [PMID: 31636082 PMCID: PMC6899038 DOI: 10.1242/dmm.040584] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 10/13/2019] [Indexed: 12/11/2022] Open
Abstract
Phosphomannomutase 2 deficiency, or PMM2-CDG, is the most common congenital disorder of glycosylation and affects over 1000 patients globally. There are no approved drugs that treat the symptoms or root cause of PMM2-CDG. To identify clinically actionable compounds that boost human PMM2 enzyme function, we performed a multispecies drug repurposing screen using a novel worm model of PMM2-CDG, followed by PMM2 enzyme functional studies in PMM2-CDG patient fibroblasts. Drug repurposing candidates from this study, and drug repurposing candidates from a previously published study using yeast models of PMM2-CDG, were tested for their effect on human PMM2 enzyme activity in PMM2-CDG fibroblasts. Of the 20 repurposing candidates discovered in the worm-based phenotypic screen, 12 were plant-based polyphenols. Insights from structure–activity relationships revealed epalrestat, the only antidiabetic aldose reductase inhibitor approved for use in humans, as a first-in-class PMM2 enzyme activator. Epalrestat increased PMM2 enzymatic activity in four PMM2-CDG patient fibroblast lines with genotypes R141H/F119L, R141H/E139K, R141H/N216I and R141H/F183S. PMM2 enzyme activity gains ranged from 30% to 400% over baseline, depending on genotype. Pharmacological inhibition of aldose reductase by epalrestat may shunt glucose from the polyol pathway to glucose-1,6-bisphosphate, which is an endogenous stabilizer and coactivator of PMM2 homodimerization. Epalrestat is a safe, oral and brain penetrant drug that was approved 27 years ago in Japan to treat diabetic neuropathy in geriatric populations. We demonstrate that epalrestat is the first small molecule activator of PMM2 enzyme activity with the potential to treat peripheral neuropathy and correct the underlying enzyme deficiency in a majority of pediatric and adult PMM2-CDG patients. Editor's choice: Drug repurposing screens using worm and patient fibroblast models of PMM2-CDG led to the discovery of epalrestat, the first activator of PMM2 that targets the root cause of disease.
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Affiliation(s)
- Sangeetha Iyer
- Perlara PBC, 2625 Alcatraz Ave #435, Berkeley, CA 94705, USA
| | - Feba S Sam
- Perlara PBC, 2625 Alcatraz Ave #435, Berkeley, CA 94705, USA
| | - Nina DiPrimio
- Perlara PBC, 2625 Alcatraz Ave #435, Berkeley, CA 94705, USA
| | - Graeme Preston
- Department of Clinical Genomics and Department of Laboratory Medicine, Mayo Clinic, Rochester, MN 55902, USA
| | - Jan Verheijen
- Department of Clinical Genomics and Department of Laboratory Medicine, Mayo Clinic, Rochester, MN 55902, USA
| | - Kausalya Murthy
- Perlara PBC, 2625 Alcatraz Ave #435, Berkeley, CA 94705, USA
| | - Zachary Parton
- Perlara PBC, 2625 Alcatraz Ave #435, Berkeley, CA 94705, USA
| | - Hillary Tsang
- Perlara PBC, 2625 Alcatraz Ave #435, Berkeley, CA 94705, USA
| | - Jessica Lao
- Perlara PBC, 2625 Alcatraz Ave #435, Berkeley, CA 94705, USA
| | - Eva Morava
- Department of Clinical Genomics and Department of Laboratory Medicine, Mayo Clinic, Rochester, MN 55902, USA
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Yeast Models of Phosphomannomutase 2 Deficiency, a Congenital Disorder of Glycosylation. G3-GENES GENOMES GENETICS 2019; 9:413-423. [PMID: 30530630 PMCID: PMC6385982 DOI: 10.1534/g3.118.200934] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Phosphomannomutase 2 Deficiency (PMM2-CDG) is the most common monogenic congenital disorder of glycosylation (CDG) affecting at least 800 patients globally. PMM2 orthologs are present in model organisms, including the budding yeast Saccharomyces cerevisiae gene SEC53. Here we describe conserved genotype-phenotype relationships across yeast and human patients between five PMM2 loss-of-function missense mutations and their orthologous SEC53 mutations. These alleles range in severity from folding defective (hypomorph) to dimerization defective (severe hypomorph) to catalytic dead (null). We included the first and second most common missense mutations – R141H, F119L respectively– and the most common compound heterozygote genotype – PMM2R141H/F119L – observed in PMM2-CDG patients. Each mutation described is expressed in haploid as well as homozygous and heterozygous diploid yeast cells at varying protein expression levels as either SEC53 protein variants or PMM2 protein variants. We developed a 384-well-plate, growth-based assay for use in a screen of the 2,560-compound Microsource Spectrum library of approved drugs, experimental drugs, tool compounds and natural products. We identified three compounds that suppress growth defects of SEC53 variants, F126L and V238M, based on the biochemical defect of the allele, protein abundance or ploidy. The rare PMM2 E139K protein variant is fully functional in yeast cells, suggesting that its pathogenicity in humans is due to the underlying DNA mutation that results in skipping of exon 5 and a nonfunctional truncated protein. Together, these results demonstrate that yeast models can be used to characterize known and novel PMM2 patient alleles in quantitative growth and enzymatic activity assays, and used as patient avatars for PMM2-CDG drug screens yielding compounds that could be rapidly cross-validated in zebrafish, rodent and human organoid models.
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13
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Frappaolo A, Sechi S, Kumagai T, Karimpour-Ghahnavieh A, Tiemeyer M, Giansanti MG. Modeling Congenital Disorders of N-Linked Glycoprotein Glycosylation in Drosophila melanogaster. Front Genet 2018; 9:436. [PMID: 30333856 PMCID: PMC6176275 DOI: 10.3389/fgene.2018.00436] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/14/2018] [Indexed: 11/13/2022] Open
Abstract
Protein glycosylation, the enzymatic addition of N-linked or O-linked glycans to proteins, serves crucial functions in animal cells and requires the action of glycosyltransferases, glycosidases and nucleotide-sugar transporters, localized in the endoplasmic reticulum and Golgi apparatus. Congenital Disorders of Glycosylation (CDGs) comprise a family of multisystemic diseases caused by mutations in genes encoding proteins involved in glycosylation pathways. CDGs are classified into two large groups. Type I CDGs affect the synthesis of the dolichol-linked Glc3Man9GlcNac2 precursor of N-linked glycosylation or its transfer to acceptor proteins. Type II CDG (CDG-II) diseases impair either the trimming of the N-linked oligosaccharide, the addition of terminal glycans or the biosynthesis of O-linked oligosaccharides, which occur in the Golgi apparatus. So far, over 100 distinct forms of CDGs are known, with the majority of them characterized by neurological defects including mental retardation, seizures and hypotonia. Yet, it is unclear how defective glycosylation causes the pathology of CDGs. This issue can be only addressed by developing animal models of specific CDGs. Drosophila melanogaster is emerging as a highly suitable organism for analyzing glycan-dependent functions in the central nervous system (CNS) and the involvement of N-glycosylation in neuropathologies. In this review we illustrate recent work that highlights the genetic and neurobiologic advantages offered by D. melanogaster for dissecting glycosylation pathways and modeling CDG pathophysiology.
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Affiliation(s)
- Anna Frappaolo
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Sapienza - Università di Roma, Rome, Italy
| | - Stefano Sechi
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Sapienza - Università di Roma, Rome, Italy
| | - Tadahiro Kumagai
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Angela Karimpour-Ghahnavieh
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Sapienza - Università di Roma, Rome, Italy
| | - Michael Tiemeyer
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States.,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Sapienza - Università di Roma, Rome, Italy
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14
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Brasil S, Pascoal C, Francisco R, Marques-da-Silva D, Andreotti G, Videira PA, Morava E, Jaeken J, Dos Reis Ferreira V. CDG Therapies: From Bench to Bedside. Int J Mol Sci 2018; 19:ijms19051304. [PMID: 29702557 PMCID: PMC5983582 DOI: 10.3390/ijms19051304] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/14/2018] [Accepted: 04/21/2018] [Indexed: 12/20/2022] Open
Abstract
Congenital disorders of glycosylation (CDG) are a group of genetic disorders that affect protein and lipid glycosylation and glycosylphosphatidylinositol synthesis. More than 100 different disorders have been reported and the number is rapidly increasing. Since glycosylation is an essential post-translational process, patients present a large range of symptoms and variable phenotypes, from very mild to extremely severe. Only for few CDG, potentially curative therapies are being used, including dietary supplementation (e.g., galactose for PGM1-CDG, fucose for SLC35C1-CDG, Mn2+ for TMEM165-CDG or mannose for MPI-CDG) and organ transplantation (e.g., liver for MPI-CDG and heart for DOLK-CDG). However, for the majority of patients, only symptomatic and preventive treatments are in use. This constitutes a burden for patients, care-givers and ultimately the healthcare system. Innovative diagnostic approaches, in vitro and in vivo models and novel biomarkers have been developed that can lead to novel therapeutic avenues aiming to ameliorate the patients’ symptoms and lives. This review summarizes the advances in therapeutic approaches for CDG.
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Affiliation(s)
- Sandra Brasil
- Portuguese Association for Congenital Disorders of Glycosylation (CDG), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
| | - Carlota Pascoal
- Portuguese Association for Congenital Disorders of Glycosylation (CDG), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Research Unit on Applied Molecular Biosciences (UCIBIO), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Lisboa, Portugal.
| | - Rita Francisco
- Portuguese Association for Congenital Disorders of Glycosylation (CDG), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Research Unit on Applied Molecular Biosciences (UCIBIO), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Lisboa, Portugal.
| | - Dorinda Marques-da-Silva
- Portuguese Association for Congenital Disorders of Glycosylation (CDG), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Research Unit on Applied Molecular Biosciences (UCIBIO), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Lisboa, Portugal.
| | - Giuseppina Andreotti
- Istituto di Chimica Biomolecolare-Consiglio Nazionale delle Ricerche (CNR), 80078 Pozzuoli, Italy.
| | - Paula A Videira
- Portuguese Association for Congenital Disorders of Glycosylation (CDG), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Research Unit on Applied Molecular Biosciences (UCIBIO), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Lisboa, Portugal.
| | - Eva Morava
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA.
| | - Jaak Jaeken
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Center for Metabolic Diseases, Universitaire Ziekenhuizen (UZ) and Katholieke Universiteit (KU) Leuven, 3000 Leuven, Belgium.
| | - Vanessa Dos Reis Ferreira
- Portuguese Association for Congenital Disorders of Glycosylation (CDG), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
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15
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Davis JK, Broadie K. Multifarious Functions of the Fragile X Mental Retardation Protein. Trends Genet 2017; 33:703-714. [PMID: 28826631 PMCID: PMC5610095 DOI: 10.1016/j.tig.2017.07.008] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/20/2017] [Accepted: 07/24/2017] [Indexed: 01/01/2023]
Abstract
Fragile X syndrome (FXS), a heritable intellectual and autism spectrum disorder (ASD), results from the loss of Fragile X mental retardation protein (FMRP). This neurodevelopmental disease state exhibits neural circuit hyperconnectivity and hyperexcitability. Canonically, FMRP functions as an mRNA-binding translation suppressor, but recent findings have enormously expanded its proposed roles. Although connections between burgeoning FMRP functions remain unknown, recent advances have extended understanding of its involvement in RNA, channel, and protein binding that modulate calcium signaling, activity-dependent critical period development, and the excitation-inhibition (E/I) neural circuitry balance. In this review, we contextualize 3 years of FXS model research. Future directions extrapolated from recent advances focus on discovering links between FMRP roles to determine whether FMRP has a multitude of unrelated functions or whether combinatorial mechanisms can explain its multifaceted existence.
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Affiliation(s)
- Jenna K Davis
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, USA.
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16
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Frappaolo A, Sechi S, Kumagai T, Robinson S, Fraschini R, Karimpour-Ghahnavieh A, Belloni G, Piergentili R, Tiemeyer KH, Tiemeyer M, Giansanti MG. COG7 deficiency in Drosophila generates multifaceted developmental, behavioral and protein glycosylation phenotypes. J Cell Sci 2017; 130:3637-3649. [PMID: 28883096 DOI: 10.1242/jcs.209049] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 09/04/2017] [Indexed: 12/14/2022] Open
Abstract
Congenital disorders of glycosylation (CDG) comprise a family of human multisystemic diseases caused by recessive mutations in genes required for protein N-glycosylation. More than 100 distinct forms of CDGs have been identified and most of them cause severe neurological impairment. The Conserved Oligomeric Golgi (COG) complex mediates tethering of vesicles carrying glycosylation enzymes across the Golgi cisternae. Mutations affecting human COG1, COG2 and COG4-COG8 cause monogenic forms of inherited, autosomal recessive CDGs. We have generated a Drosophila COG7-CDG model that closely parallels the pathological characteristics of COG7-CDG patients, including pronounced neuromotor defects associated with altered N-glycome profiles. Consistent with these alterations, larval neuromuscular junctions of Cog7 mutants exhibit a significant reduction in bouton numbers. We demonstrate that the COG complex cooperates with Rab1 and Golgi phosphoprotein 3 to regulate Golgi trafficking and that overexpression of Rab1 can rescue the cytokinesis and locomotor defects associated with loss of Cog7. Our results suggest that the Drosophila COG7-CDG model can be used to test novel potential therapeutic strategies by modulating trafficking pathways.
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Affiliation(s)
- Anna Frappaolo
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Roma, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Stefano Sechi
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Roma, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Tadahiro Kumagai
- Complex Carbohydrate Research Center, The University of Georgia, 315 Riverbend Rd., Athens, GA 30602, USA
| | - Sarah Robinson
- Complex Carbohydrate Research Center, The University of Georgia, 315 Riverbend Rd., Athens, GA 30602, USA
| | - Roberta Fraschini
- Dipartimento di Biotecnologie e Bioscienze, Università degli studi di Milano Bicocca, 20126 Milano, Italy
| | - Angela Karimpour-Ghahnavieh
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Roma, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Giorgio Belloni
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Roma, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Roberto Piergentili
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Roma, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Katherine H Tiemeyer
- Complex Carbohydrate Research Center, The University of Georgia, 315 Riverbend Rd., Athens, GA 30602, USA
| | - Michael Tiemeyer
- Complex Carbohydrate Research Center, The University of Georgia, 315 Riverbend Rd., Athens, GA 30602, USA .,Department of Biochemistry and Molecular Biology, The University of Georgia, B122 Life Sciences Building, Athens, GA 30602, USA
| | - Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Roma, Piazzale A. Moro 5, 00185 Roma, Italy
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17
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Kopke DL, Lima SC, Alexandre C, Broadie K. Notum coordinates synapse development via extracellular regulation of Wingless trans-synaptic signaling. Development 2017; 144:3499-3510. [PMID: 28860114 DOI: 10.1242/dev.148130] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 08/10/2017] [Indexed: 12/17/2022]
Abstract
Synaptogenesis requires orchestrated communication between pre- and postsynaptic cells via coordinated trans-synaptic signaling across the extracellular synaptomatrix. The first Wnt signaling ligand discovered, Drosophila Wingless (Wg; Wnt1 in mammals), plays crucial roles in synaptic development, regulating synapse architecture as well as functional differentiation. Here, we investigate synaptogenic functions of the secreted extracellular deacylase Notum, which restricts Wg signaling by cleaving an essential palmitoleate moiety. At the glutamatergic neuromuscular junction (NMJ) synapse, we find that Notum secreted from the postsynaptic muscle acts to strongly modulate synapse growth, structural architecture, ultrastructural development and functional differentiation. In Notum null flies, we find upregulated extracellular Wg ligand and nuclear trans-synaptic signal transduction, as well as downstream misregulation of both pre- and postsynaptic molecular assembly. Structural, functional and molecular synaptogenic defects are all phenocopied by Wg overexpression, suggesting that Notum acts solely by inhibiting Wg trans-synaptic signaling. Moreover, these synaptic development phenotypes are suppressed by genetically correcting Wg levels in Notum null mutants, indicating that Notum normally functions to coordinate synaptic structural and functional differentiation via negative regulation of Wg trans-synaptic signaling in the extracellular synaptomatrix.
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Affiliation(s)
- Danielle L Kopke
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, USA
| | - Sofia C Lima
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, USA
| | | | - Kendal Broadie
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, USA
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18
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Shilts J, Broadie K. Secreted tissue inhibitor of matrix metalloproteinase restricts trans-synaptic signaling to coordinate synaptogenesis. J Cell Sci 2017; 130:2344-2358. [PMID: 28576972 DOI: 10.1242/jcs.200808] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 05/29/2017] [Indexed: 12/20/2022] Open
Abstract
Synaptogenesis is coordinated by trans-synaptic signals that traverse the specialized synaptomatrix between presynaptic and postsynaptic cells. Matrix metalloproteinase (Mmp) activity sculpts this environment, balanced by secreted tissue inhibitors of Mmp (Timp). Here, we use the simplified Drosophila melanogaster matrix metalloproteome to test the consequences of eliminating all Timp regulatory control of Mmp activity at the neuromuscular junction (NMJ). Using in situ zymography, we find Timp limits Mmp activity at the NMJ terminal and shapes extracellular proteolytic dynamics surrounding individual synaptic boutons. In newly generated timp null mutants, NMJs exhibit architectural overelaboration with supernumerary synaptic boutons. With cell-targeted RNAi and rescue studies, we find that postsynaptic Timp limits presynaptic architecture. Functionally, timp null mutants exhibit compromised synaptic vesicle cycling, with activity that is lower in amplitude and fidelity. NMJ defects manifest in impaired locomotor function. Mechanistically, we find that Timp limits BMP trans-synaptic signaling and the downstream synapse-to-nucleus signal transduction. Pharmacologically restoring Mmp inhibition in timp null mutants corrects bone morphogenetic protein (BMP) signaling and synaptic properties. Genetically restoring BMP signaling in timp null mutants corrects NMJ structure and motor function. Thus, Timp inhibition of Mmp proteolytic activity restricts BMP trans-synaptic signaling to coordinate synaptogenesis.
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Affiliation(s)
- Jarrod Shilts
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, USA
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19
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Berger RP, Dookwah M, Steet R, Dalton S. Glycosylation and stem cells: Regulatory roles and application of iPSCs in the study of glycosylation-related disorders. Bioessays 2016; 38:1255-1265. [PMID: 27667795 PMCID: PMC5214967 DOI: 10.1002/bies.201600138] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Glycosylation refers to the co- and post-translational modification of protein and lipids by monosaccharides or oligosaccharide chains. The surface of mammalian cells is decorated by a heterogeneous and highly complex array of protein and lipid linked glycan structures that vary significantly between different cell types, raising questions about their roles in development and disease pathogenesis. This review will begin by focusing on recent findings that define roles for cell surface protein and lipid glycosylation in pluripotent stem cells and their functional impact during normal development. Then, we will describe how patient derived induced pluripotent stem cells are being used to model human diseases such as congenital disorders of glycosylation. Collectively, these studies indicate that cell surface glycans perform critical roles in human development and disease.
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Affiliation(s)
- Ryan P. Berger
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
- Center for Molecular Medicine, University of Georgia, Athens, GA, USA
| | - Michelle Dookwah
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Richard Steet
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Stephen Dalton
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
- Center for Molecular Medicine, University of Georgia, Athens, GA, USA
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