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Arnskötter F, da Silva PBG, Schouw ME, Lukasch C, Bianchini L, Sieber L, Garcia-Lopez J, Ahmad ST, Li Y, Lin H, Joshi P, Spänig L, Radoš M, Roiuk M, Sepp M, Zuckermann M, Northcott PA, Patrizi A, Kutscher LM. Loss of Elp1 in cerebellar granule cell progenitors models ataxia phenotype of Familial Dysautonomia. Neurobiol Dis 2024; 199:106600. [PMID: 38996985 DOI: 10.1016/j.nbd.2024.106600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 06/25/2024] [Accepted: 07/08/2024] [Indexed: 07/14/2024] Open
Abstract
Familial Dysautonomia (FD) is an autosomal recessive disorder caused by a splice site mutation in the gene ELP1, which disproportionally affects neurons. While classically characterized by deficits in sensory and autonomic neurons, neuronal defects in the central nervous system have also been described. Although ELP1 expression remains high in the normal developing and adult cerebellum, its role in cerebellar development is unknown. To explore the role of Elp1 in the cerebellum, we knocked out Elp1 in cerebellar granule cell progenitors (GCPs) and examined the outcome on animal behavior and cellular composition. We found that GCP-specific conditional knockout of Elp1 (Elp1cKO) resulted in ataxia by 8 weeks of age. Cellular characterization showed that the animals had smaller cerebella with fewer granule cells. This defect was already apparent as early as 7 days after birth, when Elp1cKO animals also had fewer mitotic GCPs and shorter Purkinje dendrites. Through molecular characterization, we found that loss of Elp1 was associated with an increase in apoptotic cell death and cell stress pathways in GCPs. Our study demonstrates the importance of ELP1 in the developing cerebellum, and suggests that loss of Elp1 in the GC lineage may also play a role in the progressive ataxia phenotypes of FD patients.
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Affiliation(s)
- Frederik Arnskötter
- Developmental Origins of Pediatric Cancer Junior Research Group, German Cancer Research Center (DKFZ), Heidelberg, Germany; Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany; National Center for Tumor Diseases (NCT), NCT Heidelberg, A partnership between DKFZ and Heidelberg University Hospital, Germany; Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Patricia Benites Goncalves da Silva
- Developmental Origins of Pediatric Cancer Junior Research Group, German Cancer Research Center (DKFZ), Heidelberg, Germany; Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany; National Center for Tumor Diseases (NCT), NCT Heidelberg, A partnership between DKFZ and Heidelberg University Hospital, Germany
| | - Mackenna E Schouw
- Developmental Origins of Pediatric Cancer Junior Research Group, German Cancer Research Center (DKFZ), Heidelberg, Germany; Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany; National Center for Tumor Diseases (NCT), NCT Heidelberg, A partnership between DKFZ and Heidelberg University Hospital, Germany
| | - Chiara Lukasch
- Developmental Origins of Pediatric Cancer Junior Research Group, German Cancer Research Center (DKFZ), Heidelberg, Germany; Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany; National Center for Tumor Diseases (NCT), NCT Heidelberg, A partnership between DKFZ and Heidelberg University Hospital, Germany
| | - Luca Bianchini
- Developmental Origins of Pediatric Cancer Junior Research Group, German Cancer Research Center (DKFZ), Heidelberg, Germany; Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany; National Center for Tumor Diseases (NCT), NCT Heidelberg, A partnership between DKFZ and Heidelberg University Hospital, Germany; Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Laura Sieber
- Developmental Origins of Pediatric Cancer Junior Research Group, German Cancer Research Center (DKFZ), Heidelberg, Germany; Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany; National Center for Tumor Diseases (NCT), NCT Heidelberg, A partnership between DKFZ and Heidelberg University Hospital, Germany
| | - Jesus Garcia-Lopez
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, USA; Center of Excellence in Neuro-Oncology Sciences (CENOS), St. Jude Children's Research Hospital, Memphis, TN, USA; Department of In vivo Pharmacology-Immunology, Tempest Therapeutics, Brisbane, CA, USA
| | - Shiekh Tanveer Ahmad
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, USA; Center of Excellence in Neuro-Oncology Sciences (CENOS), St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Yiran Li
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, USA; Center of Excellence in Neuro-Oncology Sciences (CENOS), St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Hong Lin
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, USA; Center of Excellence in Neuro-Oncology Sciences (CENOS), St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Piyush Joshi
- Developmental Origins of Pediatric Cancer Junior Research Group, German Cancer Research Center (DKFZ), Heidelberg, Germany; Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany; National Center for Tumor Diseases (NCT), NCT Heidelberg, A partnership between DKFZ and Heidelberg University Hospital, Germany
| | - Lisa Spänig
- Developmental Origins of Pediatric Cancer Junior Research Group, German Cancer Research Center (DKFZ), Heidelberg, Germany; Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany; National Center for Tumor Diseases (NCT), NCT Heidelberg, A partnership between DKFZ and Heidelberg University Hospital, Germany; Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Magdalena Radoš
- Developmental Origins of Pediatric Cancer Junior Research Group, German Cancer Research Center (DKFZ), Heidelberg, Germany; Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany; National Center for Tumor Diseases (NCT), NCT Heidelberg, A partnership between DKFZ and Heidelberg University Hospital, Germany
| | - Mykola Roiuk
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Mari Sepp
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Marc Zuckermann
- Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany; National Center for Tumor Diseases (NCT), NCT Heidelberg, A partnership between DKFZ and Heidelberg University Hospital, Germany; Division of Pediatric Neuro-Oncology, Preclinical Modeling Group, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Paul A Northcott
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, USA; Center of Excellence in Neuro-Oncology Sciences (CENOS), St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Annarita Patrizi
- Schaller Research Group, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Lena M Kutscher
- Developmental Origins of Pediatric Cancer Junior Research Group, German Cancer Research Center (DKFZ), Heidelberg, Germany; Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany; National Center for Tumor Diseases (NCT), NCT Heidelberg, A partnership between DKFZ and Heidelberg University Hospital, Germany.
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2
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Wu HF, Saito-Diaz K, Huang CW, McAlpine JL, Seo DE, Magruder DS, Ishan M, Bergeron HC, Delaney WH, Santori FR, Krishnaswamy S, Hart GW, Chen YW, Hogan RJ, Liu HX, Ivanova NB, Zeltner N. Parasympathetic neurons derived from human pluripotent stem cells model human diseases and development. Cell Stem Cell 2024; 31:734-753.e8. [PMID: 38608707 PMCID: PMC11069445 DOI: 10.1016/j.stem.2024.03.011] [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: 01/02/2023] [Revised: 01/16/2024] [Accepted: 03/13/2024] [Indexed: 04/14/2024]
Abstract
Autonomic parasympathetic neurons (parasymNs) control unconscious body responses, including "rest-and-digest." ParasymN innervation is important for organ development, and parasymN dysfunction is a hallmark of autonomic neuropathy. However, parasymN function and dysfunction in humans are vastly understudied due to the lack of a model system. Human pluripotent stem cell (hPSC)-derived neurons can fill this void as a versatile platform. Here, we developed a differentiation paradigm detailing the derivation of functional human parasymNs from Schwann cell progenitors. We employ these neurons (1) to assess human autonomic nervous system (ANS) development, (2) to model neuropathy in the genetic disorder familial dysautonomia (FD), (3) to show parasymN dysfunction during SARS-CoV-2 infection, (4) to model the autoimmune disease Sjögren's syndrome (SS), and (5) to show that parasymNs innervate white adipocytes (WATs) during development and promote WAT maturation. Our model system could become instrumental for future disease modeling and drug discovery studies, as well as for human developmental studies.
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Affiliation(s)
- Hsueh-Fu Wu
- Center for Molecular Medicine, University of Georgia, Athens, GA 30602, USA; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Kenyi Saito-Diaz
- Center for Molecular Medicine, University of Georgia, Athens, GA 30602, USA
| | - Chia-Wei Huang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Jessica L McAlpine
- Center for Molecular Medicine, University of Georgia, Athens, GA 30602, USA; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Dong Eun Seo
- Center for Molecular Medicine, University of Georgia, Athens, GA 30602, USA; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - D Sumner Magruder
- Department of Genetics, Department of Computer Science, Wu Tsai Institute, Program for Computational Biology and Bioinformatics, Yale University, New Haven, CT 06520, USA
| | - Mohamed Ishan
- Regenerative Bioscience Center, Department of Animal and Dairy Science College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA 30602, USA
| | - Harrison C Bergeron
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - William H Delaney
- Center for Molecular Medicine, University of Georgia, Athens, GA 30602, USA
| | - Fabio R Santori
- Center for Molecular Medicine, University of Georgia, Athens, GA 30602, USA
| | - Smita Krishnaswamy
- Department of Genetics, Department of Computer Science, Wu Tsai Institute, Program for Computational Biology and Bioinformatics, Yale University, New Haven, CT 06520, USA
| | - Gerald W Hart
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Ya-Wen Chen
- Department of Otolaryngology, Department of Cell, Developmental, and Regenerative Biology, Institute for Airway Sciences, Institute for Regenerative Medicine, Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Robert J Hogan
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA; Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Hong-Xiang Liu
- Regenerative Bioscience Center, Department of Animal and Dairy Science College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA 30602, USA
| | - Natalia B Ivanova
- Center for Molecular Medicine, University of Georgia, Athens, GA 30602, USA; Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Nadja Zeltner
- Center for Molecular Medicine, University of Georgia, Athens, GA 30602, USA; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA; Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA.
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3
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Harripaul R, Morini E, Salani M, Logan E, Kirchner E, Bolduc J, Chekuri A, Currall B, Yadav R, Erdin S, Talkowski ME, Gao D, Slaugenhaupt S. Transcriptome analysis in a humanized mouse model of familial dysautonomia reveals tissue-specific gene expression disruption in the peripheral nervous system. Sci Rep 2024; 14:570. [PMID: 38177237 PMCID: PMC10766950 DOI: 10.1038/s41598-023-51137-6] [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: 10/31/2023] [Accepted: 12/31/2023] [Indexed: 01/06/2024] Open
Abstract
Familial dysautonomia (FD) is a rare recessive neurodevelopmental disease caused by a splice mutation in the Elongator acetyltransferase complex subunit 1 (ELP1) gene. This mutation results in a tissue-specific reduction of ELP1 protein, with the lowest levels in the central and peripheral nervous systems (CNS and PNS, respectively). FD patients exhibit complex neurological phenotypes due to the loss of sensory and autonomic neurons. Disease symptoms include decreased pain and temperature perception, impaired or absent myotatic reflexes, proprioceptive ataxia, and progressive retinal degeneration. While the involvement of the PNS in FD pathogenesis has been clearly recognized, the underlying mechanisms responsible for the preferential neuronal loss remain unknown. In this study, we aimed to elucidate the molecular mechanisms underlying FD by conducting a comprehensive transcriptome analysis of neuronal tissues from the phenotypic mouse model TgFD9; Elp1Δ20/flox. This mouse recapitulates the same tissue-specific ELP1 mis-splicing observed in patients while modeling many of the disease manifestations. Comparison of FD and control transcriptomes from dorsal root ganglion (DRG), trigeminal ganglion (TG), medulla (MED), cortex, and spinal cord (SC) showed significantly more differentially expressed genes (DEGs) in the PNS than the CNS. We then identified genes that were tightly co-expressed and functionally dependent on the level of full-length ELP1 transcript. These genes, defined as ELP1 dose-responsive genes, were combined with the DEGs to generate tissue-specific dysregulated FD signature genes and networks. Within the PNS networks, we observed direct connections between Elp1 and genes involved in tRNA synthesis and genes related to amine metabolism and synaptic signaling. Importantly, transcriptomic dysregulation in PNS tissues exhibited enrichment for neuronal subtype markers associated with peptidergic nociceptors and myelinated sensory neurons, which are known to be affected in FD. In summary, this study has identified critical tissue-specific gene networks underlying the etiology of FD and provides new insights into the molecular basis of the disease.
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Affiliation(s)
- Ricardo Harripaul
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Program in Medical and Population Genetics and Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Elisabetta Morini
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Monica Salani
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Emily Logan
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Emily Kirchner
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Jessica Bolduc
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Anil Chekuri
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Benjamin Currall
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Program in Medical and Population Genetics and Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Rachita Yadav
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Program in Medical and Population Genetics and Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Serkan Erdin
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Program in Medical and Population Genetics and Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Michael E Talkowski
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Program in Medical and Population Genetics and Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Dadi Gao
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA.
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
| | - Susan Slaugenhaupt
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA.
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
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4
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Macefield VG, Smith LJ, Norcliffe‐Kaufmann L, Palma J, Kaufmann H. Sensorimotor control in the congenital absence of functional muscle spindles. Exp Physiol 2024; 109:27-34. [PMID: 37029664 PMCID: PMC10988665 DOI: 10.1113/ep090768] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 03/22/2023] [Indexed: 04/09/2023]
Abstract
Hereditary sensory and autonomic neuropathy type III (HSAN III), also known as familial dysautonomia or Riley-Day syndrome, results from an autosomal recessive genetic mutation that causes a selective loss of specific sensory neurones, leading to greatly elevated pain and temperature thresholds, poor proprioception, marked ataxia and disturbances in blood pressure control. Stretch reflexes are absent throughout the body, which can be explained by the absence of functional muscle spindle afferents - assessed by intraneural microelectrodes inserted into peripheral nerves in the upper and lower limbs. This also explains the greatly compromised proprioception at the knee joint, as assessed by passive joint-angle matching. Moreover, there is a tight correlation between loss of proprioceptive acuity at the knee and the severity of gait impairment. Surprisingly, proprioception is normal at the elbow, suggesting that participants are relying more on sensory cues from the overlying skin; microelectrode recordings have shown that myelinated tactile afferents in the upper and lower limbs appear to be normal. Nevertheless, the lack of muscle spindles does affect sensorimotor control in the upper limb: in addition to poor performance in the finger-to-nose test, manual performance in the Purdue pegboard task is much worse than in age-matched healthy controls. Unlike those rare individuals with large-fibre sensory neuropathy, in which both muscle spindle and cutaneous afferents are absent, those with HSAN III present as a means of assessing sensorimotor control following the selective loss of muscle spindle afferents.
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Affiliation(s)
| | - Lyndon J. Smith
- School of MedicineWestern Sydney UniversitySydneyNew South WalesAustralia
| | - Lucy Norcliffe‐Kaufmann
- Dysautonomia Center, Department of NeurologyNew York University School of MedicineNew YorkNYUSA
| | - Jose‐Alberto Palma
- Dysautonomia Center, Department of NeurologyNew York University School of MedicineNew YorkNYUSA
| | - Horacio Kaufmann
- Dysautonomia Center, Department of NeurologyNew York University School of MedicineNew YorkNYUSA
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5
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Schultz A, Cheng SY, Kirchner E, Costello S, Miettinen H, Chaverra M, King C, George L, Zhao X, Narasimhan J, Weetall M, Slaugenhaupt S, Morini E, Punzo C, Lefcort F. Reduction of retinal ganglion cell death in mouse models of familial dysautonomia using AAV-mediated gene therapy and splicing modulators. Sci Rep 2023; 13:18600. [PMID: 37903840 PMCID: PMC10616160 DOI: 10.1038/s41598-023-45376-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 10/18/2023] [Indexed: 11/01/2023] Open
Abstract
Familial dysautonomia (FD) is a rare neurodevelopmental and neurodegenerative disease caused by a splicing mutation in the Elongator Acetyltransferase Complex Subunit 1 (ELP1) gene. The reduction in ELP1 mRNA and protein leads to the death of retinal ganglion cells (RGCs) and visual impairment in all FD patients. Currently patient symptoms are managed, but there is no treatment for the disease. We sought to test the hypothesis that restoring levels of Elp1 would thwart the death of RGCs in FD. To this end, we tested the effectiveness of two therapeutic strategies for rescuing RGCs. Here we provide proof-of-concept data that gene replacement therapy and small molecule splicing modifiers effectively reduce the death of RGCs in mouse models for FD and provide pre-clinical foundational data for translation to FD patients.
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Affiliation(s)
- Anastasia Schultz
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Shun-Yun Cheng
- Department of Ophthalmology, Neurobiology and Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Emily Kirchner
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Stephanann Costello
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Heini Miettinen
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Marta Chaverra
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Colin King
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Lynn George
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
- Department of Biological and Physical Science, Montana State University Billings, Billings, MT, USA
| | - Xin Zhao
- PTC Therapeutics, Inc., South Plainfield, NJ, 07080, USA
| | | | - Marla Weetall
- PTC Therapeutics, Inc., South Plainfield, NJ, 07080, USA
| | - Susan Slaugenhaupt
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA
| | - Elisabetta Morini
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA
| | - Claudio Punzo
- Department of Ophthalmology, Neurobiology and Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Frances Lefcort
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA.
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6
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Harripaul R, Morini E, Salani M, Logan E, Kirchner E, Bolduc J, Chekuri A, Currall B, Yadav R, Erdin S, Talkowski ME, Gao D, Slaugenhaupt S. Transcriptome analysis in a humanized mouse model of familial dysautonomia reveals tissue-specific gene expression disruption in the peripheral nervous system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.28.559870. [PMID: 37808686 PMCID: PMC10557663 DOI: 10.1101/2023.09.28.559870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Familial dysautonomia (FD) is a rare recessive neurodevelopmental disease caused by a splice mutation in the Elongator acetyltransferase complex subunit 1 ( ELP1 ) gene. This mutation results in a tissue-specific reduction of ELP1 protein, with the lowest levels in the central and peripheral nervous systems (CNS and PNS, respectively). FD patients exhibit complex neurological phenotypes due to the loss of sensory and autonomic neurons. Disease symptoms include decreased pain and temperature perception, impaired or absent myotatic reflexes, proprioceptive ataxia, and progressive retinal degeneration. While the involvement of the PNS in FD pathogenesis has been clearly recognized, the underlying mechanisms responsible for the preferential neuronal loss remain unknown. In this study, we aimed to elucidate the molecular mechanisms underlying FD by conducting a comprehensive transcriptome analysis of neuronal tissues from the phenotypic mouse model TgFD9 ; Elp1 Δ 20/flox . This mouse recapitulates the same tissue-specific ELP1 mis-splicing observed in patients while modeling many of the disease manifestations. Comparison of FD and control transcriptomes from dorsal root ganglion (DRG), trigeminal ganglion (TG), medulla (MED), cortex, and spinal cord (SC) showed significantly more differentially expressed genes (DEGs) in the PNS than the CNS. We then identified genes that were tightly co-expressed and functionally dependent on the level of full-length ELP1 transcript. These genes, defined as ELP1 dose-responsive genes, were combined with the DEGs to generate tissue-specific dysregulated FD signature genes and networks. Within the PNS networks, we observed direct connections between Elp1 and genes involved in tRNA synthesis and genes related to amine metabolism and synaptic signaling. Importantly, transcriptomic dysregulation in PNS tissues exhibited enrichment for neuronal subtype markers associated with peptidergic nociceptors and myelinated sensory neurons, which are known to be affected in FD. In summary, this study has identified critical tissue-specific gene networks underlying the etiology of FD and provides new insights into the molecular basis of the disease.
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7
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Schultz A, Cheng SY, Kirchner E, Costello S, Miettinen H, Chaverra M, King C, George L, Zhao X, Narasimhan J, Weetall M, Slaugenhaupt S, Morini E, Punzo C, Lefcort F. Reduction of retinal ganglion cell death in mouse models of familial dysautonomia using AAV-mediated gene therapy and splicing modulators. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.22.541535. [PMID: 37293016 PMCID: PMC10245894 DOI: 10.1101/2023.05.22.541535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Familial dysautonomia (FD) is a rare neurodevelopmental and neurodegenerative disease caused by a splicing mutation in the Elongator Acetyltransferase Complex Subunit 1 ( ELP1 ) gene. The reduction in ELP1 mRNA and protein leads to the death of retinal ganglion cells (RGCs) and visual impairment in all FD patients. Currently, patient symptoms are managed, but there is no treatment for the disease. We sought to test the hypothesis that restoring levels of Elp1 would thwart the death of RGCs in FD. To this end, we tested the effectiveness of two therapeutic strategies for rescuing RGCs. Here we provide proof-of-concept data that gene replacement therapy and small molecule splicing modifiers effectively reduce the death of RGCs in mouse models for FD and provide pre-clinical data foundation for translation to FD patients.
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8
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Saito-Diaz K, Dietrich P, Wu HF, Sun X, Patel AJ, Wzientek CG, Prudden AR, Boons GJ, Chen S, Studer L, Xu B, Dragatsis I, Zeltner N. Genipin Crosslinks the Extracellular Matrix to Rescue Developmental and Degenerative Defects, and Accelerates Regeneration of Peripheral Neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.22.533831. [PMID: 36993570 PMCID: PMC10055431 DOI: 10.1101/2023.03.22.533831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The peripheral nervous system (PNS) is essential for proper body function. A high percentage of the population suffer nerve degeneration or peripheral damage. For example, over 40% of patients with diabetes or undergoing chemotherapy develop peripheral neuropathies. Despite this, there are major gaps in the knowledge of human PNS development and therefore, there are no available treatments. Familial Dysautonomia (FD) is a devastating disorder that specifically affects the PNS making it an ideal model to study PNS dysfunction. FD is caused by a homozygous point mutation in ELP1 leading to developmental and degenerative defects in the sensory and autonomic lineages. We previously employed human pluripotent stem cells (hPSCs) to show that peripheral sensory neurons (SNs) are not generated efficiently and degenerate over time in FD. Here, we conducted a chemical screen to identify compounds able to rescue this SN differentiation inefficiency. We identified that genipin, a compound prescribed in Traditional Chinese Medicine for neurodegenerative disorders, restores neural crest and SN development in FD, both in the hPSC model and in a FD mouse model. Additionally, genipin prevented FD neuronal degeneration, suggesting that it could be offered to patients suffering from PNS neurodegenerative disorders. We found that genipin crosslinks the extracellular matrix, increases the stiffness of the ECM, reorganizes the actin cytoskeleton, and promotes transcription of YAP-dependent genes. Finally, we show that genipin enhances axon regeneration in an in vitro axotomy model in healthy sensory and sympathetic neurons (part of the PNS) and in prefrontal cortical neurons (part of the central nervous system, CNS). Our results suggest genipin can be used as a promising drug candidate for treatment of neurodevelopmental and neurodegenerative diseases, and as a enhancer of neuronal regeneration.
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Affiliation(s)
- Kenyi Saito-Diaz
- Center for Molecular Medicine, University of Georgia, Athens GA, USA
| | - Paula Dietrich
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, TN, USA
| | - Hsueh-Fu Wu
- Center for Molecular Medicine, University of Georgia, Athens GA, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens GA, USA
| | - Xin Sun
- College of Engineering, University of Georgia, Athens GA, USA
| | | | | | | | - Geert-Jan Boons
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
- Department of Chemistry, University of Georgia, Athens, GA, USA
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Shuibing Chen
- Department of Surgery and Department of Biochemistry at Weill Cornell Medical College, New York, NY, USA
- Center for Stem Cell Biology, Sloan Kettering Institute, New York, NY, USA
| | - Lorenz Studer
- Center for Stem Cell Biology, Sloan Kettering Institute, New York, NY, USA
- Department of Developmental Biology, Sloan Kettering Institute, New York, NY, USA
| | - Bingqian Xu
- College of Engineering, University of Georgia, Athens GA, USA
| | - Ioannis Dragatsis
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, TN, USA
| | - Nadja Zeltner
- Center for Molecular Medicine, University of Georgia, Athens GA, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens GA, USA
- Department of Cellular Biology, University of Georgia, Athens GA, USA
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9
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Morini E, Chekuri A, Logan EM, Bolduc JM, Kirchner EG, Salani M, Krauson AJ, Narasimhan J, Gabbeta V, Grover S, Dakka A, Mollin A, Jung SP, Zhao X, Zhang N, Zhang S, Arnold M, Woll MG, Naryshkin NA, Weetall M, Slaugenhaupt SA. Development of an oral treatment that rescues gait ataxia and retinal degeneration in a phenotypic mouse model of familial dysautonomia. Am J Hum Genet 2023; 110:531-547. [PMID: 36809767 PMCID: PMC10027479 DOI: 10.1016/j.ajhg.2023.01.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 01/30/2023] [Indexed: 02/22/2023] Open
Abstract
Familial dysautonomia (FD) is a rare neurodegenerative disease caused by a splicing mutation in elongator acetyltransferase complex subunit 1 (ELP1). This mutation leads to the skipping of exon 20 and a tissue-specific reduction of ELP1, mainly in the central and peripheral nervous systems. FD is a complex neurological disorder accompanied by severe gait ataxia and retinal degeneration. There is currently no effective treatment to restore ELP1 production in individuals with FD, and the disease is ultimately fatal. After identifying kinetin as a small molecule able to correct the ELP1 splicing defect, we worked on its optimization to generate novel splicing modulator compounds (SMCs) that can be used in individuals with FD. Here, we optimize the potency, efficacy, and bio-distribution of second-generation kinetin derivatives to develop an oral treatment for FD that can efficiently pass the blood-brain barrier and correct the ELP1 splicing defect in the nervous system. We demonstrate that the novel compound PTC258 efficiently restores correct ELP1 splicing in mouse tissues, including brain, and most importantly, prevents the progressive neuronal degeneration that is characteristic of FD. Postnatal oral administration of PTC258 to the phenotypic mouse model TgFD9;Elp1Δ20/flox increases full-length ELP1 transcript in a dose-dependent manner and leads to a 2-fold increase in functional ELP1 in the brain. Remarkably, PTC258 treatment improves survival, gait ataxia, and retinal degeneration in the phenotypic FD mice. Our findings highlight the great therapeutic potential of this novel class of small molecules as an oral treatment for FD.
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Affiliation(s)
- Elisabetta Morini
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA; Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA.
| | - Anil Chekuri
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA; Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA; Grousbeck Gene Therapy Center, Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | - Emily M Logan
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Jessica M Bolduc
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Emily G Kirchner
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Monica Salani
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Aram J Krauson
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | | | | | | | - Amal Dakka
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | - Anna Mollin
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | | | - Xin Zhao
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | - Nanjing Zhang
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | - Sophie Zhang
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | | | | | | | - Marla Weetall
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | - Susan A Slaugenhaupt
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA; Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA.
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10
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Wu HF, Yu W, Saito-Diaz K, Huang CW, Carey J, Lefcort F, Hart GW, Liu HX, Zeltner N. Norepinephrine transporter defects lead to sympathetic hyperactivity in Familial Dysautonomia models. Nat Commun 2022; 13:7032. [PMID: 36396637 PMCID: PMC9671909 DOI: 10.1038/s41467-022-34811-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 11/08/2022] [Indexed: 11/19/2022] Open
Abstract
Familial dysautonomia (FD), a rare neurodevelopmental and neurodegenerative disorder affects the sympathetic and sensory nervous system. Although almost all patients harbor a mutation in ELP1, it remains unresolved exactly how function of sympathetic neurons (symNs) is affected; knowledge critical for understanding debilitating disease hallmarks, including cardiovascular instability or dysautonomic crises, that result from dysregulated sympathetic activity. Here, we employ the human pluripotent stem cell (hPSC) system to understand symN disease mechanisms and test candidate drugs. FD symNs are intrinsically hyperactive in vitro, in cardiomyocyte co-cultures, and in animal models. We report reduced norepinephrine transporter expression, decreased intracellular norepinephrine (NE), decreased NE re-uptake, and excessive extracellular NE in FD symNs. SymN hyperactivity is not a direct ELP1 mutation result, but may connect to NET via RAB proteins. We found that candidate drugs lowered hyperactivity independent of ELP1 modulation. Our findings may have implications for other symN disorders and may allow future drug testing and discovery.
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Affiliation(s)
- Hsueh-Fu Wu
- Center for Molecular Medicine, University of Georgia, Athens, GA, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | - Wenxin Yu
- Regenerative Bioscience Center, Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, USA
| | - Kenyi Saito-Diaz
- Center for Molecular Medicine, University of Georgia, Athens, GA, USA
| | - Chia-Wei Huang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Joseph Carey
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Frances Lefcort
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Gerald W Hart
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Hong-Xiang Liu
- Regenerative Bioscience Center, Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, USA
| | - Nadja Zeltner
- Center for Molecular Medicine, University of Georgia, Athens, GA, USA.
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.
- Department of Cellular Biology, University of Georgia, Athens, GA, USA.
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11
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Rescue of a familial dysautonomia mouse model by AAV9-Exon-specific U1 snRNA. Am J Hum Genet 2022; 109:1534-1548. [PMID: 35905737 PMCID: PMC9388384 DOI: 10.1016/j.ajhg.2022.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 06/30/2022] [Indexed: 02/06/2023] Open
Abstract
Familial dysautonomia (FD) is a currently untreatable, neurodegenerative disease caused by a splicing mutation (c.2204+6T>C) that causes skipping of exon 20 of the elongator complex protein 1 (ELP1) pre-mRNA. Here, we used adeno-associated virus serotype 9 (AAV9-U1-FD) to deliver an exon-specific U1 (ExSpeU1) small nuclear RNA, designed to cause inclusion of ELP1 exon 20 only in those cells expressing the target pre-mRNA, in a phenotypic mouse model of FD. Postnatal systemic and intracerebral ventricular treatment in these mice increased the inclusion of ELP1 exon 20. This also augmented the production of functional protein in several tissues including brain, dorsal root, and trigeminal ganglia. Crucially, the treatment rescued most of the FD mouse mortality before one month of age (89% vs 52%). There were notable improvements in ataxic gait as well as renal (serum creatinine) and cardiac (ejection fraction) functions. RNA-seq analyses of dorsal root ganglia from treated mice and human cells overexpressing FD-ExSpeU1 revealed only minimal global changes in gene expression and splicing. Overall then, our data prove that AAV9-U1-FD is highly specific and will likely be a safe and effective therapeutic strategy for this debilitating disease.
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12
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Willems M, Wells CF, Coubes C, Pequignot M, Kuony A, Michon F. Hypolacrimia and Alacrimia as Diagnostic Features for Genetic or Congenital Conditions. Invest Ophthalmol Vis Sci 2022; 63:3. [PMID: 35925585 PMCID: PMC9363675 DOI: 10.1167/iovs.63.9.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
As part of the lacrimal apparatus, the lacrimal gland participates in the maintenance of a healthy eye surface by producing the aqueous part of the tear film. Alacrimia and hypolacrimia, which are relatively rare during childhood or young adulthood, have their origin in a number of mechanisms which include agenesia, aplasia, hypoplasia, or incorrect maturation of the gland. Moreover, impaired innervation of the gland and/or the cornea and alterations of protein secretion pathways can lead to a defective tear film. In most conditions leading to alacrimia or hypolacrimia, however, the altered tear film is only one of numerous defects that arise and therefore is commonly disregarded. Here, we have systematically reviewed all of those genetic conditions or congenital disorders that have alacrimia or hypolacrimia as a feature. Where it is known, we describe the mechanism of the defect in question. It has been possible to clearly establish the physiopathology of only a minority of these conditions. As hypolacrimia and alacrimia are rare features, this review could be used as a tool in clinical genetics to perform a quick diagnosis, necessary for appropriate care and counseling.
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Affiliation(s)
- Marjolaine Willems
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM, Montpellier, France.,Medical Genetic Department for Rare Diseases and Personalized Medicine, Reference Center AD SOOR, AnDDI-RARE, Montpellier University Hospital Center, Montpellier, France
| | - Constance F Wells
- Medical Genetic Department for Rare Diseases and Personalized Medicine, Reference Center AD SOOR, AnDDI-RARE, Montpellier University Hospital Center, Montpellier, France
| | - Christine Coubes
- Medical Genetic Department for Rare Diseases and Personalized Medicine, Reference Center AD SOOR, AnDDI-RARE, Montpellier University Hospital Center, Montpellier, France
| | - Marie Pequignot
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM, Montpellier, France
| | - Alison Kuony
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM, Montpellier, France.,Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Frederic Michon
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM, Montpellier, France
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13
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Chekuri A, Logan EM, Krauson AJ, Salani M, Ackerman S, Kirchner EG, Bolduc JM, Wang X, Dietrich P, Dragatsis I, Vandenberghe LH, Slaugenhaupt SA, Morini E. Selective retinal ganglion cell loss and optic neuropathy in a humanized mouse model of familial dysautonomia. Hum Mol Genet 2022; 31:1776-1787. [PMID: 34908112 PMCID: PMC9169455 DOI: 10.1093/hmg/ddab359] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 11/21/2022] Open
Abstract
Familial dysautonomia (FD) is an autosomal recessive neurodegenerative disease caused by a splicing mutation in the gene encoding Elongator complex protein 1 (ELP1, also known as IKBKAP). This mutation results in tissue-specific skipping of exon 20 with a corresponding reduction of ELP1 protein, predominantly in the central and peripheral nervous system. Although FD patients have a complex neurological phenotype caused by continuous depletion of sensory and autonomic neurons, progressive visual decline leading to blindness is one of the most problematic aspects of the disease, as it severely affects their quality of life. To better understand the disease mechanism as well as to test the in vivo efficacy of targeted therapies for FD, we have recently generated a novel phenotypic mouse model, TgFD9; IkbkapΔ20/flox. This mouse exhibits most of the clinical features of the disease and accurately recapitulates the tissue-specific splicing defect observed in FD patients. Driven by the dire need to develop therapies targeting retinal degeneration in FD, herein, we comprehensively characterized the progression of the retinal phenotype in this mouse, and we demonstrated that it is possible to correct ELP1 splicing defect in the retina using the splicing modulator compound (SMC) BPN-15477.
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Affiliation(s)
- Anil Chekuri
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA
- Grousbeck Gene Therapy Center, Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | - Emily M Logan
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Aram J Krauson
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Monica Salani
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Sophie Ackerman
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Emily G Kirchner
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Jessica M Bolduc
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Xia Wang
- Grousbeck Gene Therapy Center, Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | - Paula Dietrich
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, TN, USA
| | - Ioannis Dragatsis
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, TN, USA
| | - Luk H Vandenberghe
- Grousbeck Gene Therapy Center, Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | - Susan A Slaugenhaupt
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA
| | - Elisabetta Morini
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
- Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA
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14
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Tolman Z, Chaverra M, George L, Lefcort F. Elp1 is required for development of visceral sensory peripheral and central circuitry. Dis Model Mech 2022; 15:275184. [PMID: 35481599 PMCID: PMC9187870 DOI: 10.1242/dmm.049274] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 04/20/2022] [Indexed: 11/23/2022] Open
Abstract
Cardiovascular instability and a blunted respiratory drive in hypoxic conditions are hallmark features of the genetic sensory and autonomic neuropathy, familial dysautonomia (FD). FD results from a mutation in the gene ELP1, the encoded protein of which is a scaffolding subunit of the six-subunit Elongator complex. In mice, we and others have shown that Elp1 is essential for the normal development of neural crest-derived dorsal root ganglia sensory neurons. Whether Elp1 is also required for development of ectodermal placode-derived visceral sensory receptors, which are required for normal baroreception and chemosensory responses, has not been investigated. Using mouse models for FD, we here show that the entire circuitry underlying baroreception and chemoreception is impaired due to a requirement for Elp1 in the visceral sensory neuron ganglia, as well as for normal peripheral target innervation, and in their central nervous system synaptic partners in the medulla. Thus, Elp1 is required in both placode- and neural crest-derived sensory neurons, and its reduction aborts the normal development of neuronal circuitry essential for autonomic homeostasis and interoception. This article has an associated First Person interview with the first author of the paper. Summary: Our data indicate that Elp1 is required in both placode- and neural crest-derived sensory neurons, and that it exerts comparable effects, including survival, axonal morphology and target innervation in both lineages.
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Affiliation(s)
- Zariah Tolman
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Marta Chaverra
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Lynn George
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA.,Department of Biological and Physical Sciences, Montana State University Billings, Billings, MT 59101, USA
| | - Frances Lefcort
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
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15
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Leonard CE, Quiros J, Lefcort F, Taneyhill LA. Loss of Elp1 disrupts trigeminal ganglion neurodevelopment in a model of familial dysautonomia. eLife 2022; 11:71455. [PMID: 35713404 PMCID: PMC9273214 DOI: 10.7554/elife.71455] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 06/17/2022] [Indexed: 01/28/2023] Open
Abstract
Familial dysautonomia (FD) is a sensory and autonomic neuropathy caused by mutations in elongator complex protein 1 (ELP1). FD patients have small trigeminal nerves and impaired facial pain and temperature perception. These signals are relayed by nociceptive neurons in the trigeminal ganglion, a structure that is composed of both neural crest- and placode-derived cells. Mice lacking Elp1 in neural crest derivatives ('Elp1 CKO') are born with small trigeminal ganglia, suggesting Elp1 is important for trigeminal ganglion development, yet the function of Elp1 in this context is unknown. We demonstrate that Elp1, expressed in both neural crest- and placode-derived neurons, is not required for initial trigeminal ganglion formation. However, Elp1 CKO trigeminal neurons exhibit abnormal axon outgrowth and deficient target innervation. Developing nociceptors expressing the receptor TrkA undergo early apoptosis in Elp1 CKO, while TrkB- and TrkC-expressing neurons are spared, indicating Elp1 supports the target innervation and survival of trigeminal nociceptors. Furthermore, we demonstrate that specific TrkA deficits in the Elp1 CKO trigeminal ganglion reflect the neural crest lineage of most TrkA neurons versus the placodal lineage of most TrkB and TrkC neurons. Altogether, these findings explain defects in cranial gangliogenesis that may lead to loss of facial pain and temperature sensation in FD.
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Affiliation(s)
- Carrie E Leonard
- Department of Avian and Animal Sciences, University of Maryland, College ParkCollege ParkUnited States
| | - Jolie Quiros
- Department of Avian and Animal Sciences, University of Maryland, College ParkCollege ParkUnited States
| | - Frances Lefcort
- Department of Microbiology and Cell Biology, Montana State UniversityBozemanUnited States
| | - Lisa A Taneyhill
- Department of Avian and Animal Sciences, University of Maryland, College ParkCollege ParkUnited States
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16
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Vahidi G, Flook H, Sherk V, Mergy M, Lefcort F, Heveran CM. Bone biomechanical properties and tissue-scale bone quality in a genetic mouse model of familial dysautonomia. Osteoporos Int 2021; 32:2335-2346. [PMID: 34036438 PMCID: PMC8563419 DOI: 10.1007/s00198-021-06006-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 05/11/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE Familial dysautonomia (FD) is associated with a high prevalence of bone fractures, but the impacts of the disease on bone mass and quality are unclear. The purpose of this study was to evaluate tissue through whole-bone scale bone quality in a mouse model of FD. METHODS Femurs from mature adult Tuba1a-Cre; Elp1LoxP/LoxP conditional knockouts (CKO) (F = 7, M = 4) and controls (F = 5, M = 6) were evaluated for whole-bone flexural material properties, trabecular microarchitecture and cortical geometry, and areal bone mineral density (BMD). Adjacent maps spanning the thickness of femur midshaft cortical bone assessed tissue-scale modulus (nanoindentation), bone mineralization, mineral maturity, and collagen secondary structure (Raman spectroscopy). RESULTS Consistent with prior studies on this mouse model, the Elp1 CKO mouse model recapitulated several key hallmarks of human FD, with one difference being the male mice tended to have a more severe phenotype than females. Deletion of Elp1 in neurons (using the neuronal-specific Tuba1a-cre) led to a significantly reduced whole-bone toughness but not strength or modulus. Elp1 CKO female mice had reduced trabecular microarchitecture (BV/TV, Tb.Th, Conn.D.) but not cortical geometry. The mutant mice also had a small but significant reduction in cortical bone nanoindentation modulus. While bone tissue mineralization and mineral maturity were not impaired, FD mice may have altered collagen secondary structure. Changes in collagen secondary structure were inversely correlated with bone toughness. BMD from dual-energy x-ray absorptiometry (DXA) was unchanged with FD. CONCLUSION The deletion of Elp1 in neurons is sufficient to generate a mouse line which demonstrates loss of whole-bone toughness, consistent with the poor bone quality suspected in the clinical setting. The Elp1 CKO model, as with human FD, impacts the nervous system, gut, kidney function, mobility, gait, and posture. The bone quality phenotype of Elp1 CKO mice, which includes altered microarchitecture and tissue-scale material properties, is complex and likely influenced by these multisystemic changes. This mouse model may provide a useful platform to not only investigate the mechanisms responsible for bone fragility in FD, but also a powerful model system with which to evaluate potential therapeutic interventions for bone fragility in FD patients.
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Affiliation(s)
- G Vahidi
- Department of Mechanical & Industrial Engineerings, Montana State University, Bozeman, MT, USA
| | - H Flook
- Department of Mechanical & Industrial Engineerings, Montana State University, Bozeman, MT, USA
| | - V Sherk
- Department of Orthopaedics, University of Colorado School of Medicine, Aurora, CO, USA
| | - M Mergy
- Department of Microbiology & Immunology, Montana State University, Bozeman, MT, USA
| | - F Lefcort
- Department of Microbiology & Immunology, Montana State University, Bozeman, MT, USA
| | - C M Heveran
- Department of Mechanical & Industrial Engineerings, Montana State University, Bozeman, MT, USA.
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17
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Macefield VG. The roles of mechanoreceptors in muscle and skin in human proprioception. CURRENT OPINION IN PHYSIOLOGY 2021. [DOI: 10.1016/j.cophys.2021.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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18
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Ghosh S, Li L, Tourtellotte WG. Retrograde nerve growth factor signaling abnormalities and the pathogenesis of familial dysautonomia. Neural Regen Res 2021; 16:1795-1796. [PMID: 33510081 PMCID: PMC8328778 DOI: 10.4103/1673-5374.306081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Soumitra Ghosh
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Lin Li
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Warren G Tourtellotte
- Department of Pathology and Laboratory Medicine; Department of Neurology; Department of Neurosurgery; Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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19
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Abstract
Investigations of the cellular and molecular mechanisms that mediate the development of the autonomic nervous system have identified critical genes and signaling pathways that, when disrupted, cause disorders of the autonomic nervous system. This review summarizes our current understanding of how the autonomic nervous system emerges from the organized spatial and temporal patterning of precursor cell migration, proliferation, communication, and differentiation, and discusses potential clinical implications for developmental disorders of the autonomic nervous system, including familial dysautonomia, Hirschsprung disease, Rett syndrome, and congenital central hypoventilation syndrome.
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Affiliation(s)
- Frances Lefcort
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, Montana
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20
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Smith L, Norcliffe-Kaufmann L, Palma JA, Kaufmann H, Macefield VG. Elbow proprioception is normal in patients with a congenital absence of functional muscle spindles. J Physiol 2020; 598:3521-3529. [PMID: 32452029 DOI: 10.1113/jp279931] [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: 04/04/2020] [Accepted: 05/13/2020] [Indexed: 01/24/2023] Open
Abstract
KEY POINTS Individuals with hereditary sensory and autonomic neuropathy type III (HSAN III), also known as Riley-Day syndrome or familial dysautonomia, do not have functional muscle spindle afferents but do have essentially normal cutaneous mechanoreceptors. Lack of muscle spindle feedback from the legs may account for the poor proprioception at the knee and the ataxic gait typical of HSAN III. Given that functional muscle spindle afferents are also absent in the upper limb, we assessed whether proprioception at the elbow was likewise compromised. Passive joint angle matching showed that proprioception was normal at the elbow, suggesting that individuals with HSAN III rely more on cutaneous afferents around the elbow. ABSTRACT Hereditary sensory and autonomic neuropathy type III (HSAN III) is a rare neurological condition that features a marked ataxic gait that progressively worsens over time. We have shown that functional muscle spindle afferents are absent in the upper and lower limbs in HSAN III, and we have argued that this may account for the ataxia. We recently used passive joint angle matching to demonstrate that proprioception of the knee joint is very poor in HSAN III but can be improved towards normal by application of elastic kinesiology tape across the knee joints, which we attribute to the presence of intact cutaneous mechanoreceptors. Here we assessed whether proprioception was equally compromised at the elbow joint, and whether it could be improved through taping. Proprioception at the elbow joint was assessed using passive joint angle matching in 12 HSAN III patients and 12 age-matched controls. There was no difference in absolute error, gradient or correlation coefficient of the relationship between joint angles of the reference and indicator arms. Unlike at the knee, taping did not improve elbow proprioception in either group. Clearly, the lack of muscle spindles compromised proprioception at the knee but not at the elbow, and we suggest that the HSAN III patients rely more on proprioceptive signals from the skin around the elbow.
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Affiliation(s)
- Lyndon Smith
- School of Medicine, Western Sydney University, Sydney, Australia
| | - Lucy Norcliffe-Kaufmann
- Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, USA
| | - Jose-Alberto Palma
- Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, USA
| | - Horacio Kaufmann
- Dysautonomia Center, Department of Neurology, New York University School of Medicine, New York, USA
| | - Vaughan G Macefield
- School of Medicine, Western Sydney University, Sydney, Australia.,Neuroscience Research Australia, Sydney, Australia.,Baker Heart and Diabetes Institute, Melbourne, Australia
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21
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Sinha R, Kim YJ, Nomakuchi T, Sahashi K, Hua Y, Rigo F, Bennett CF, Krainer AR. Antisense oligonucleotides correct the familial dysautonomia splicing defect in IKBKAP transgenic mice. Nucleic Acids Res 2019; 46:4833-4844. [PMID: 29672717 PMCID: PMC6007753 DOI: 10.1093/nar/gky249] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/28/2018] [Indexed: 12/19/2022] Open
Abstract
Familial dysautonomia (FD) is a rare inherited neurodegenerative disorder caused by a point mutation in the IKBKAP gene that results in defective splicing of its pre-mRNA. The mutation weakens the 5′ splice site of exon 20, causing this exon to be skipped, thereby introducing a premature termination codon. Though detailed FD pathogenesis mechanisms are not yet clear, correcting the splicing defect in the relevant tissue(s), thus restoring normal expression levels of the full-length IKAP protein, could be therapeutic. Splice-switching antisense oligonucleotides (ASOs) can be effective targeted therapeutics for neurodegenerative diseases, such as nusinersen (Spinraza), an approved drug for spinal muscular atrophy. Using a two-step screen with ASOs targeting IKBKAP exon 20 or the adjoining intronic regions, we identified a lead ASO that fully restored exon 20 splicing in FD patient fibroblasts. We also characterized the corresponding cis-acting regulatory sequences that control exon 20 splicing. When administered into a transgenic FD mouse model, the lead ASO promoted expression of full-length human IKBKAP mRNA and IKAP protein levels in several tissues tested, including the central nervous system. These findings provide insights into the mechanisms of IKBKAP exon 20 recognition, and pre-clinical proof of concept for an ASO-based targeted therapy for FD.
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Affiliation(s)
- Rahul Sinha
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.,Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Young Jin Kim
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.,Stony Brook University School of Medicine, Stony Brook, NY 11790, USA
| | - Tomoki Nomakuchi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.,Stony Brook University School of Medicine, Stony Brook, NY 11790, USA
| | - Kentaro Sahashi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.,Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Yimin Hua
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.,Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215123, China
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA 92008, USA
| | | | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
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22
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ELP1 Splicing Correction Reverses Proprioceptive Sensory Loss in Familial Dysautonomia. Am J Hum Genet 2019; 104:638-650. [PMID: 30905397 DOI: 10.1016/j.ajhg.2019.02.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 02/08/2019] [Indexed: 12/14/2022] Open
Abstract
Familial dysautonomia (FD) is a recessive neurodegenerative disease caused by a splice mutation in Elongator complex protein 1 (ELP1, also known as IKBKAP); this mutation leads to variable skipping of exon 20 and to a drastic reduction of ELP1 in the nervous system. Clinically, many of the debilitating aspects of the disease are related to a progressive loss of proprioception; this loss leads to severe gait ataxia, spinal deformities, and respiratory insufficiency due to neuromuscular incoordination. There is currently no effective treatment for FD, and the disease is ultimately fatal. The development of a drug that targets the underlying molecular defect provides hope that the drastic peripheral neurodegeneration characteristic of FD can be halted. We demonstrate herein that the FD mouse TgFD9;IkbkapΔ20/flox recapitulates the proprioceptive impairment observed in individuals with FD, and we provide the in vivo evidence that postnatal correction, promoted by the small molecule kinetin, of the mutant ELP1 splicing can rescue neurological phenotypes in FD. Daily administration of kinetin starting at birth improves sensory-motor coordination and prevents the onset of spinal abnormalities by stopping the loss of proprioceptive neurons. These phenotypic improvements correlate with increased amounts of full-length ELP1 mRNA and protein in multiple tissues, including in the peripheral nervous system (PNS). Our results show that postnatal correction of the underlying ELP1 splicing defect can rescue devastating disease phenotypes and is therefore a viable therapeutic approach for persons with FD.
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23
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Saito-Diaz K, Zeltner N. Induced pluripotent stem cells for disease modeling, cell therapy and drug discovery in genetic autonomic disorders: a review. Clin Auton Res 2019; 29:367-384. [PMID: 30631982 DOI: 10.1007/s10286-018-00587-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 12/26/2018] [Indexed: 12/19/2022]
Abstract
The autonomic nervous system (ANS) regulates all organs in the body independent of consciousness, and is thus essential for maintaining homeostasis of the entire organism. Diseases of the ANS can arise due to environmental insults such as injury, toxins/drugs and infections or due to genetic lesions. Human studies and animal models have been instrumental to understanding connectivity and regulation of the ANS and its disorders. However, research into cellular pathologies and molecular mechanisms of ANS disorders has been hampered by the difficulties in accessing human patient-derived ANS cells in large numbers to conduct meaningful research, mainly because patient neurons cannot be easily biopsied and primary human neuronal cultures cannot be expanded.Human-induced pluripotent stem cell (hiPSC) technology can elegantly bridge these issues, allowing unlimited access of patient-derived ANS cell types for cellular, molecular and biochemical analysis, facilitating the discovery of novel therapeutic targets, and eventually leading to drug discovery. Additionally, such cells may provide a source for cell replacement therapy to replenish lost or injured ANS tissue in patients.Here, we first review the anatomy and embryonic development of the ANS, as this knowledge is crucial for understanding disease modeling approaches. We then review the current advances in human stem cell technology for modeling diseases of the ANS, recent strides toward cell replacement therapy and drug discovery initiatives.
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Affiliation(s)
- Kenyi Saito-Diaz
- Center for Molecular Medicine, University of Georgia, Athens, GA, USA
| | - Nadja Zeltner
- Center for Molecular Medicine, University of Georgia, Athens, GA, USA. .,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA. .,Department of Cellular Biology, University of Georgia, Athens, GA, USA.
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24
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Montes M, Sanford BL, Comiskey DF, Chandler DS. RNA Splicing and Disease: Animal Models to Therapies. Trends Genet 2019; 35:68-87. [PMID: 30466729 PMCID: PMC6339821 DOI: 10.1016/j.tig.2018.10.002] [Citation(s) in RCA: 121] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 10/01/2018] [Accepted: 10/16/2018] [Indexed: 02/07/2023]
Abstract
Alternative splicing of pre-mRNA increases genetic diversity, and recent studies estimate that most human multiexon genes are alternatively spliced. If this process is not highly regulated and accurate, it leads to mis-splicing events, which may result in proteins with altered function. A growing body of work has implicated mis-splicing events in a range of diseases, including cancer, neurodegenerative diseases, and muscular dystrophies. Understanding the mechanisms that cause aberrant splicing events and how this leads to disease is vital for designing effective therapeutic strategies. In this review, we focus on advances in therapies targeting splicing, and highlight the animal models developed to recapitulate disease phenotypes as a model for testing these therapies.
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Affiliation(s)
- Matías Montes
- Molecular, Cellular, and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA; Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Brianne L Sanford
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Daniel F Comiskey
- Molecular, Cellular, and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA; Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Dawn S Chandler
- Molecular, Cellular, and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA; Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.
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25
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Slijkerman R, Goloborodko A, Broekman S, de Vrieze E, Hetterschijt L, Peters T, Gerits M, Kremer H, van Wijk E. Poor Splice-Site Recognition in a Humanized Zebrafish Knockin Model for the Recurrent Deep-Intronic c.7595-2144A>G Mutation in USH2A. Zebrafish 2018; 15:597-609. [PMID: 30281416 DOI: 10.1089/zeb.2018.1613] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The frequent deep-intronic c.7595-2144A>G mutation in intron 40 of USH2A generates a high-quality splice donor site, resulting in the incorporation of a pseudoexon (PE40) into the mature transcript that is predicted to prematurely terminate usherin translation. Aberrant USH2A pre-mRNA splicing could be corrected in patient-derived fibroblasts using antisense oligonucleotides. With the aim to study the effect of the c.7595-2144A>G mutation and USH2A splice redirection on retinal function, a humanized zebrafish knockin model was generated, in which 670 basepairs of ush2a intron 40 were exchanged for 557 basepairs of the corresponding human sequence using an optimized CRISPR/Cas9-based protocol. However, in the retina of adult homozygous humanized zebrafish, only 7.4% ± 3.9% of ush2a transcripts contained the human PE40 sequence and immunohistochemical analyses revealed no differences in the usherin expression and localization between the retina of humanized and wild-type zebrafish larvae. Nevertheless, we were able to partially correct aberrant ush2a splicing using a PE40-targeting antisense morpholino. Our results indicate a clear difference in splice-site recognition by the human and zebrafish splicing machinery. Therefore, we propose a protocol in which the effect of human splice-modulating mutations is studied in a zebrafish-specific cell-based splice assay before the generation of a humanized zebrafish knockin model.
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Affiliation(s)
- Ralph Slijkerman
- 1 Department of Otorhinolaryngology, Radboud University Medical Center , Nijmegen, the Netherlands .,2 Radboud Institute for Molecular Life Sciences, and Radboud University Medical Center , Nijmegen, the Netherlands
| | - Alexander Goloborodko
- 3 Department of Human Genetics, Radboud University Medical Center , Nijmegen, the Netherlands
| | - Sanne Broekman
- 1 Department of Otorhinolaryngology, Radboud University Medical Center , Nijmegen, the Netherlands .,4 Donders Institute for Brain , Cognition, and Behavior, Nijmegen, the Netherlands
| | - Erik de Vrieze
- 1 Department of Otorhinolaryngology, Radboud University Medical Center , Nijmegen, the Netherlands .,4 Donders Institute for Brain , Cognition, and Behavior, Nijmegen, the Netherlands
| | - Lisette Hetterschijt
- 1 Department of Otorhinolaryngology, Radboud University Medical Center , Nijmegen, the Netherlands .,4 Donders Institute for Brain , Cognition, and Behavior, Nijmegen, the Netherlands
| | - Theo Peters
- 1 Department of Otorhinolaryngology, Radboud University Medical Center , Nijmegen, the Netherlands .,4 Donders Institute for Brain , Cognition, and Behavior, Nijmegen, the Netherlands
| | - Milou Gerits
- 3 Department of Human Genetics, Radboud University Medical Center , Nijmegen, the Netherlands
| | - Hannie Kremer
- 1 Department of Otorhinolaryngology, Radboud University Medical Center , Nijmegen, the Netherlands .,3 Department of Human Genetics, Radboud University Medical Center , Nijmegen, the Netherlands .,4 Donders Institute for Brain , Cognition, and Behavior, Nijmegen, the Netherlands
| | - Erwin van Wijk
- 1 Department of Otorhinolaryngology, Radboud University Medical Center , Nijmegen, the Netherlands .,4 Donders Institute for Brain , Cognition, and Behavior, Nijmegen, the Netherlands
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26
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Donadon I, Pinotti M, Rajkowska K, Pianigiani G, Barbon E, Morini E, Motaln H, Rogelj B, Mingozzi F, Slaugenhaupt SA, Pagani F. Exon-specific U1 snRNAs improve ELP1 exon 20 definition and rescue ELP1 protein expression in a familial dysautonomia mouse model. Hum Mol Genet 2018; 27:2466-2476. [PMID: 29701768 PMCID: PMC6030917 DOI: 10.1093/hmg/ddy151] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 04/12/2018] [Accepted: 04/16/2018] [Indexed: 12/30/2022] Open
Abstract
Familial dysautonomia (FD) is a rare genetic disease with no treatment, caused by an intronic point mutation (c.2204+6T>C) that negatively affects the definition of exon 20 in the elongator complex protein 1 gene (ELP1 also known as IKBKAP). This substitution modifies the 5' splice site and, in combination with regulatory splicing factors, induces different levels of exon 20 skipping, in various tissues. Here, we evaluated the therapeutic potential of a novel class of U1 snRNA molecules, exon-specific U1s (ExSpeU1s), in correcting ELP1 exon 20 recognition. Lentivirus-mediated expression of ELP1-ExSpeU1 in FD fibroblasts improved ELP1 splicing and protein levels. We next focused on a transgenic mouse model that recapitulates the same tissue-specific mis-splicing seen in FD patients. Intraperitoneal delivery of ELP1-ExSpeU1s-adeno-associated virus particles successfully increased the production of full-length human ELP1 transcript and protein. This splice-switching class of molecules is the first to specifically correct the ELP1 exon 20 splicing defect. Our data provide proof of principle of ExSpeU1s-adeno-associated virus particles as a novel therapeutic strategy for FD.
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Affiliation(s)
- Irving Donadon
- Human Molecular Genetics Laboratory, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Mirko Pinotti
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Katarzyna Rajkowska
- Human Molecular Genetics Laboratory, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Giulia Pianigiani
- Human Molecular Genetics Laboratory, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | | | - Elisabetta Morini
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA
| | - Helena Motaln
- Department of Biotechnology, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Boris Rogelj
- Department of Biotechnology, Jožef Stefan Institute, Ljubljana, Slovenia
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
- Biomedical Research Institute BRIS, Ljubljana, Slovenia
| | - Federico Mingozzi
- Genethon and INSERM U951, Evry, France
- University Pierre and Marie Curie and INSERM U974, Paris, France
| | - Susan A Slaugenhaupt
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA
| | - Franco Pagani
- Human Molecular Genetics Laboratory, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
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27
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Rubin BY, Anderson SL. IKBKAP/ELP1 gene mutations: mechanisms of familial dysautonomia and gene-targeting therapies. APPLICATION OF CLINICAL GENETICS 2017; 10:95-103. [PMID: 29290691 PMCID: PMC5735983 DOI: 10.2147/tacg.s129638] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The successful completion of the Human Genome Project led to the discovery of the molecular basis of thousands of genetic disorders. The identification of the mutations that cause familial dysautonomia (FD), an autosomal recessive disorder that impacts sensory and autonomic neurons, was aided by the release of the human DNA sequence. The identification and characterization of the genetic cause of FD have changed the natural history of this disease. Genetic testing programs, which were established shortly after the disease-causing mutations were identified, have almost completely eliminated the birth of children with this disorder. Characterization of the principal disease-causing mutation has led to the development of therapeutic modalities that ameliorate its effect, while the development of mouse models that recapitulate the impact of the mutation has allowed for the in-depth characterization of its impact on neuronal development and survival. The intense research focus on this disorder, while clearly benefiting the FD patient population, also serves as a model for the positive impact focused research efforts can have on the future of other genetic diseases. Here, we present the research advances and scientific breakthroughs that have changed and will continue to change the natural history of this centuries-old genetic disease.
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Affiliation(s)
- Berish Y Rubin
- Department of Biological Sciences, Fordham University, Bronx, NY, USA
| | - Sylvia L Anderson
- Department of Biological Sciences, Fordham University, Bronx, NY, USA
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28
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Ohe K, Yoshida M, Nakano-Kobayashi A, Hosokawa M, Sako Y, Sakuma M, Okuno Y, Usui T, Ninomiya K, Nojima T, Kataoka N, Hagiwara M. RBM24 promotes U1 snRNP recognition of the mutated 5' splice site in the IKBKAP gene of familial dysautonomia. RNA (NEW YORK, N.Y.) 2017; 23:1393-1403. [PMID: 28592461 PMCID: PMC5558909 DOI: 10.1261/rna.059428.116] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 05/25/2017] [Indexed: 06/07/2023]
Abstract
The 5' splice site mutation (IVS20+6T>C) of the inhibitor of κ light polypeptide gene enhancer in B cells, kinase complex-associated protein (IKBKAP) gene in familial dysautonomia (FD) is at the sixth intronic nucleotide of the 5' splice site. It is known to weaken U1 snRNP recognition and result in an aberrantly spliced mRNA product in neuronal tissue, but normally spliced mRNA in other tissues. Aberrantly spliced IKBKAP mRNA abrogates IKK complex-associated protein (IKAP)/elongator protein 1 (ELP1) expression and results in a defect of neuronal cell development in FD. To elucidate the tissue-dependent regulatory mechanism, we screened an expression library of major RNA-binding proteins (RBPs) with our mammalian dual-color splicing reporter system and identified RBM24 as a regulator. RBM24 functioned as a cryptic intronic splicing enhancer binding to an element (IVS20+13-29) downstream from the intronic 5' splice site mutation in the IKBKAP gene and promoted U1 snRNP recognition only to the mutated 5' splice site (and not the wild-type 5' splice site). Our results show that tissue-specific expression of RBM24 can explain the neuron-specific aberrant splicing of IKBKAP exon 20 in familial dysautonomia, and that ectopic expression of RBM24 in neuronal tissue could be a novel therapeutic target of the disease.
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Affiliation(s)
- Kenji Ohe
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
- Training Program of Leaders for Integrated Medical System for Fruitful Healthy-Longevity Society (LIMS), Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Mayumi Yoshida
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Akiko Nakano-Kobayashi
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Motoyasu Hosokawa
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yukiya Sako
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Maki Sakuma
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yukiko Okuno
- Medical Research Support Center, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Tomomi Usui
- Laboratory of Gene Expression, School of Biomedical Science, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Kensuke Ninomiya
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Takayuki Nojima
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Naoyuki Kataoka
- Laboratory for Malignancy Control Research, Medical Innovation Center, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8507, Japan
- Laboratory of Cell Regulation, Departments of Applied Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Masatoshi Hagiwara
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
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29
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Animal and cellular models of familial dysautonomia. Clin Auton Res 2017; 27:235-243. [PMID: 28667575 DOI: 10.1007/s10286-017-0438-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/15/2017] [Indexed: 12/11/2022]
Abstract
Since Riley and Day first described the clinical phenotype of patients with familial dysautonomia (FD) over 60 years ago, the field has made considerable progress clinically, scientifically, and translationally in treating and understanding the etiology of FD. FD is classified as a hereditary sensory and autonomic neuropathy (HSAN type III) and is both a developmental and a progressive neurodegenerative condition that results from an autosomal recessive mutation in the gene IKBKAP, also known as ELP1. FD primarily impacts the peripheral nervous system but also manifests in central nervous system disruption, especially in the retina and optic nerve. While the disease is rare, the rapid progress being made in elucidating the molecular and cellular mechanisms mediating the demise of neurons in FD should provide insight into degenerative pathways common to many neurological disorders. Interestingly, the protein encoded by IKBKAP/ELP1, IKAP or ELP1, is a key scaffolding subunit of the six-subunit Elongator complex, and variants in other Elongator genes are associated with amyotrophic lateral sclerosis (ALS), intellectual disability, and Rolandic epilepsy. Here we review the recent model systems that are revealing the molecular and cellular pathophysiological mechanisms mediating FD. These powerful model systems can now be used to test targeted therapeutics for mitigating neuronal loss in FD and potentially other disorders.
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30
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Hervé M, Ibrahim EC. Proteasome inhibitors to alleviate aberrant IKBKAP mRNA splicing and low IKAP/hELP1 synthesis in familial dysautonomia. Neurobiol Dis 2017; 103:113-122. [PMID: 28404519 DOI: 10.1016/j.nbd.2017.04.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 03/23/2017] [Accepted: 04/05/2017] [Indexed: 12/27/2022] Open
Abstract
FD is a rare neurodegenerative disorder caused by a mutation of the IKBKAP gene, which induces low expression levels of the Elongator subunit IKAP/hELP1 protein. A rational strategy for FD treatment could be to identify drugs increasing IKAP/hELP1 expression levels by blocking protein degradation pathways such as the 26S proteasome. Proteasome inhibitors are promising molecules emerging in cancer treatment and could thus constitute an enticing pharmaceutical strategy for FD treatment. Therefore, we tested three proteasome inhibitors on FD human olfactory ecto-mesenchymal stem cells (hOE-MSCs): two approved by the Food and Drug Administration (FDA) and European Medicines Agency (EMA), bortezomib and carfilzomib, as well as epoxomicin. Although all 3 inhibitors demonstrated activity in correcting IKBKAP mRNA aberrant splicing, carfilzomib was superior in enhancing IKAP/hELP1 quantity. Moreover, we observed a synergistic effect of suboptimal doses of carfilzomib on kinetin in improving IKBKAP isoforms ratio and IKAP/hELP1 expression levels allowing to counterbalance carfilzomib toxicity. Finally, we identified several dysregulated miRNAs after carfilzomib treatment that target proteasome-associated mRNAs and determined that IKAP/hELP1 deficiency in FD pathology is correlated to an overactivity of the 26S proteasome. Altogether, these results reinforce the rationale for using chemical compounds inhibiting the 26S proteasome as an innovative option for FD and a promising therapeutic pathway for many other neurodegenerative diseases.
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Affiliation(s)
- Mylène Hervé
- Aix-Marseille Univ, CNRS, CRN2M, 13344 Marseille Cedex 15, France
| | - El Chérif Ibrahim
- Aix-Marseille Univ, CNRS, CRN2M, 13344 Marseille Cedex 15, France; Aix-Marseille Univ, CNRS, INT, Inst Neurosci Timone, 13385 Marseille Cedex 5, France.
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31
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Chaverra M, George L, Mergy M, Waller H, Kujawa K, Murnion C, Sharples E, Thorne J, Podgajny N, Grindeland A, Ueki Y, Eiger S, Cusick C, Babcock AM, Carlson GA, Lefcort F. The familial dysautonomia disease gene IKBKAP is required in the developing and adult mouse central nervous system. Dis Model Mech 2017; 10:605-618. [PMID: 28167615 PMCID: PMC5451171 DOI: 10.1242/dmm.028258] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 01/23/2017] [Indexed: 02/06/2023] Open
Abstract
Hereditary sensory and autonomic neuropathies (HSANs) are a genetically and clinically diverse group of disorders defined by peripheral nervous system (PNS) dysfunction. HSAN type III, known as familial dysautonomia (FD), results from a single base mutation in the gene IKBKAP that encodes a scaffolding unit (ELP1) for a multi-subunit complex known as Elongator. Since mutations in other Elongator subunits (ELP2 to ELP4) are associated with central nervous system (CNS) disorders, the goal of this study was to investigate a potential requirement for Ikbkap in the CNS of mice. The sensory and autonomic pathophysiology of FD is fatal, with the majority of patients dying by age 40. While signs and pathology of FD have been noted in the CNS, the clinical and research focus has been on the sensory and autonomic dysfunction, and no genetic model studies have investigated the requirement for Ikbkap in the CNS. Here, we report, using a novel mouse line in which Ikbkap is deleted solely in the nervous system, that not only is Ikbkap widely expressed in the embryonic and adult CNS, but its deletion perturbs both the development of cortical neurons and their survival in adulthood. Primary cilia in embryonic cortical apical progenitors and motile cilia in adult ependymal cells are reduced in number and disorganized. Furthermore, we report that, in the adult CNS, both autonomic and non-autonomic neuronal populations require Ikbkap for survival, including spinal motor and cortical neurons. In addition, the mice developed kyphoscoliosis, an FD hallmark, indicating its neuropathic etiology. Ultimately, these perturbations manifest in a developmental and progressive neurodegenerative condition that includes impairments in learning and memory. Collectively, these data reveal an essential function for Ikbkap that extends beyond the peripheral nervous system to CNS development and function. With the identification of discrete CNS cell types and structures that depend on Ikbkap, novel strategies to thwart the progressive demise of CNS neurons in FD can be developed. Summary:Ikbkap is essential for normal CNS development, neuronal survival and behavior, adding to our understanding of the role of the Elongator complex in the mammalian CNS.
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Affiliation(s)
- Marta Chaverra
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Lynn George
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA.,Department of Biological and Physical Sciences, Montana State University Billings, Billings, MT 59101, USA
| | - Marc Mergy
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Hannah Waller
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Katharine Kujawa
- Department of Psychology, Montana State University, Bozeman, MT 59717, USA
| | - Connor Murnion
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Ezekiel Sharples
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Julian Thorne
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA.,University of Washington, School of Medicine, Seattle, WA 98195, USA
| | - Nathaniel Podgajny
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | | | - Yumi Ueki
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Steven Eiger
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - Cassie Cusick
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
| | - A Michael Babcock
- Department of Psychology, Montana State University, Bozeman, MT 59717, USA
| | | | - Frances Lefcort
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717, USA
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Pei Y, Lewis AE, Robertson ES. Current Progress in EBV-Associated B-Cell Lymphomas. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1018:57-74. [PMID: 29052132 DOI: 10.1007/978-981-10-5765-6_5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Epstein-Barr virus (EBV) was the first human tumor virus discovered more than 50 years ago. EBV-associated lymphomagenesis is still a significant viral-associated disease as it involves a diverse range of pathologies, especially B-cell lymphomas. Recent development of high-throughput next-generation sequencing technologies and in vivo mouse models have significantly promoted our understanding of the fundamental molecular mechanisms which drive these cancers and allowed for the development of therapeutic intervention strategies. This review will highlight the current advances in EBV-associated B-cell lymphomas, focusing on transcriptional regulation, chromosome aberrations, in vivo studies of EBV-mediated lymphomagenesis, as well as the treatment strategies to target viral-associated lymphomas.
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Affiliation(s)
- Yonggang Pei
- Department of Otorhinolaryngology-Head and Neck Surgery, and Microbiology, Tumor Virology Program, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, 3610 Hamilton Walk, 201E Johnson Pavilion, Philadelphia, PA, 19104, USA
| | - Alexandria E Lewis
- Department of Otorhinolaryngology-Head and Neck Surgery, and Microbiology, Tumor Virology Program, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, 3610 Hamilton Walk, 201E Johnson Pavilion, Philadelphia, PA, 19104, USA
| | - Erle S Robertson
- Department of Otorhinolaryngology-Head and Neck Surgery, and Microbiology, Tumor Virology Program, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, 3610 Hamilton Walk, 201E Johnson Pavilion, Philadelphia, PA, 19104, USA.
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Naftelberg S, Abramovitch Z, Gluska S, Yannai S, Joshi Y, Donyo M, Ben-Yaakov K, Gradus T, Zonszain J, Farhy C, Ashery-Padan R, Perlson E, Ast G. Phosphatidylserine Ameliorates Neurodegenerative Symptoms and Enhances Axonal Transport in a Mouse Model of Familial Dysautonomia. PLoS Genet 2016; 12:e1006486. [PMID: 27997532 PMCID: PMC5172536 DOI: 10.1371/journal.pgen.1006486] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 11/15/2016] [Indexed: 12/03/2022] Open
Abstract
Familial Dysautonomia (FD) is a neurodegenerative disease in which aberrant tissue-specific splicing of IKBKAP exon 20 leads to reduction of IKAP protein levels in neuronal tissues. Here we generated a conditional knockout (CKO) mouse in which exon 20 of IKBKAP is deleted in the nervous system. The CKO FD mice exhibit developmental delays, sensory abnormalities, and less organized dorsal root ganglia (DRGs) with attenuated axons compared to wild-type mice. Furthermore, the CKO FD DRGs show elevated HDAC6 levels, reduced acetylated α-tubulin, unstable microtubules, and impairment of axonal retrograde transport of nerve growth factor (NGF). These abnormalities in DRG properties underlie neuronal degeneration and FD symptoms. Phosphatidylserine treatment decreased HDAC6 levels and thus increased acetylation of α-tubulin. Further PS treatment resulted in recovery of axonal outgrowth and enhanced retrograde axonal transport by decreasing histone deacetylase 6 (HDAC6) levels and thus increasing acetylation of α-tubulin levels. Thus, we have identified the molecular pathway that leads to neurodegeneration in FD and have demonstrated that phosphatidylserine treatment has the potential to slow progression of neurodegeneration. We create a novel FD mouse model, in which exon 20 of IKBKAP was deleted in the nervous system, to study the role of IKAP in the neurodegeneration process. The lack of IKBKAP exon 20 impaired retrograde nerve growth factor (NGF) transport and axonal outgrowth. Reduction of IKAP levels resulted in elevated HDAC6 levels and thus reduced acetylated α-tubulin levels. Phosphatidylserine down-regulated HDAC6 levels, furthermore phosphatidylserine treatment facilitated axonal transport and stabilized microtubules. In brief: Naftelberg et al. identify the molecular pathway leading to neurodegeneration using a mouse model of familial dysautonomia and suggest that phosphatidylserine acts as an HDAC6 inhibitor to improve neurologic function.
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Affiliation(s)
- Shiran Naftelberg
- Department of Human Molecular Genetics and Biochemestry. Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ziv Abramovitch
- Department of Human Molecular Genetics and Biochemestry. Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shani Gluska
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Sivan Yannai
- Department of Human Molecular Genetics and Biochemestry. Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yuvraj Joshi
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Maya Donyo
- Department of Human Molecular Genetics and Biochemestry. Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Keren Ben-Yaakov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Tal Gradus
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Jonathan Zonszain
- Department of Human Molecular Genetics and Biochemestry. Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Chen Farhy
- Department of Human Molecular Genetics and Biochemestry. Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ruth Ashery-Padan
- Department of Human Molecular Genetics and Biochemestry. Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eran Perlson
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- * E-mail: (EP); (GA)
| | - Gil Ast
- Department of Human Molecular Genetics and Biochemestry. Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- * E-mail: (EP); (GA)
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Capturing the biology of disease severity in a PSC-based model of familial dysautonomia. Nat Med 2016; 22:1421-1427. [PMID: 27841875 DOI: 10.1038/nm.4220] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Accepted: 09/30/2016] [Indexed: 02/08/2023]
Abstract
Familial dysautonomia (FD) is a debilitating disorder that affects derivatives of the neural crest (NC). For unknown reasons, people with FD show marked differences in disease severity despite carrying an identical, homozygous point mutation in IKBKAP, encoding IκB kinase complex-associated protein. Here we present disease-related phenotypes in human pluripotent stem cells (PSCs) that capture FD severity. Cells from individuals with severe but not mild disease show impaired specification of NC derivatives, including autonomic and sensory neurons. In contrast, cells from individuals with severe and mild FD show defects in peripheral neuron survival, indicating that neurodegeneration is the main culprit for cases of mild FD. Although genetic repair of the FD-associated mutation reversed early developmental NC defects, sensory neuron specification was not restored, indicating that other factors may contribute to disease severity. Whole-exome sequencing identified candidate modifier genes for individuals with severe FD. Our study demonstrates that PSC-based modeling is sensitive in recapitulating disease severity, which presents an important step toward personalized medicine.
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Loss of Ikbkap Causes Slow, Progressive Retinal Degeneration in a Mouse Model of Familial Dysautonomia. eNeuro 2016; 3:eN-NWR-0143-16. [PMID: 27699209 PMCID: PMC5037323 DOI: 10.1523/eneuro.0143-16.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 09/09/2016] [Accepted: 09/14/2016] [Indexed: 01/30/2023] Open
Abstract
Familial dysautonomia (FD) is an autosomal recessive congenital neuropathy that is caused by a mutation in the gene for inhibitor of kappa B kinase complex-associated protein (IKBKAP). Although FD patients suffer from multiple neuropathies, a major debilitation that affects their quality of life is progressive blindness. To determine the requirement for Ikbkap in the developing and adult retina, we generated Ikbkap conditional knockout (CKO) mice using a TUBA1a promoter-Cre (Tα1-Cre). In the retina, Tα1-Cre expression is detected predominantly in retinal ganglion cells (RGCs). At 6 months, significant loss of RGCs had occurred in the CKO retinas, with the greatest loss in the temporal retina, which is the same spatial phenotype observed in FD, Leber hereditary optic neuropathy, and dominant optic atrophy. Interestingly, the melanopsin-positive RGCs were resistant to degeneration. By 9 months, signs of photoreceptor degeneration were observed, which later progressed to panretinal degeneration, including RGC and photoreceptor loss, optic nerve thinning, Müller glial activation, and disruption of layers. Taking these results together, we conclude that although Ikbkap is not required for normal development of RGCs, its loss causes a slow, progressive RGC degeneration most severely in the temporal retina, which is later followed by indirect photoreceptor loss and complete retinal disorganization. This mouse model of FD is not only useful for identifying the mechanisms mediating retinal degeneration, but also provides a model system in which to attempt to test therapeutics that may mitigate the loss of vision in FD patients.
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Dietrich P, Dragatsis I. Familial Dysautonomia: Mechanisms and Models. Genet Mol Biol 2016; 39:497-514. [PMID: 27561110 PMCID: PMC5127153 DOI: 10.1590/1678-4685-gmb-2015-0335] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 03/16/2016] [Indexed: 11/22/2022] Open
Abstract
Hereditary Sensory and Autonomic Neuropathies (HSANs) compose a heterogeneous group of genetic disorders characterized by sensory and autonomic dysfunctions. Familial Dysautonomia (FD), also known as HSAN III, is an autosomal recessive disorder that affects 1/3,600 live births in the Ashkenazi Jewish population. The major features of the disease are already present at birth and are attributed to abnormal development and progressive degeneration of the sensory and autonomic nervous systems. Despite clinical interventions, the disease is inevitably fatal. FD is caused by a point mutation in intron 20 of the IKBKAP gene that results in severe reduction in expression of IKAP, its encoded protein. In vitro and in vivo studies have shown that IKAP is involved in multiple intracellular processes, and suggest that failed target innervation and/or impaired neurotrophic retrograde transport are the primary causes of neuronal cell death in FD. However, FD is far more complex, and appears to affect several other organs and systems in addition to the peripheral nervous system. With the recent generation of mouse models that recapitulate the molecular and pathological features of the disease, it is now possible to further investigate the mechanisms underlying different aspects of the disorder, and to test novel therapeutic strategies.
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Affiliation(s)
- Paula Dietrich
- Department of Physiology, The University of Tennessee, Memphis, TN, USA
| | - Ioannis Dragatsis
- Department of Physiology, The University of Tennessee, Memphis, TN, USA
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Hervé M, Ibrahim EC. MicroRNA screening identifies a link between NOVA1 expression and a low level of IKAP in familial dysautonomia. Dis Model Mech 2016; 9:899-909. [PMID: 27483351 PMCID: PMC5007982 DOI: 10.1242/dmm.025841] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 06/22/2016] [Indexed: 12/20/2022] Open
Abstract
Familial dysautonomia (FD) is a rare neurodegenerative disease caused by a mutation in intron 20 of the IKBKAP gene (c.2204+6T>C), leading to tissue-specific skipping of exon 20 and a decrease in the synthesis of the encoded protein IKAP (also known as ELP1). Small non-coding RNAs known as microRNAs (miRNAs) are important post-transcriptional regulators of gene expression and play an essential role in the nervous system development and function. To better understand the neuronal specificity of IKAP loss, we examined expression of miRNAs in human olfactory ecto-mesenchymal stem cells (hOE-MSCs) from five control individuals and five FD patients. We profiled the expression of 373 miRNAs using microfluidics and reverse transcription coupled to quantitative PCR (RT-qPCR) on two biological replicate series of hOE-MSC cultures from healthy controls and FD patients. This led to the total identification of 26 dysregulated miRNAs in FD, validating the existence of a miRNA signature in FD. We then selected the nine most discriminant miRNAs for further analysis. The signaling pathways affected by these dysregulated miRNAs were largely within the nervous system. In addition, many targets of these dysregulated miRNAs had been previously demonstrated to be affected in FD models. Moreover, we found that four of our nine candidate miRNAs target the neuron-specific splicing factor NOVA1. We demonstrated that overexpression of miR-203a-3p leads to a decrease of NOVA1, counter-balanced by an increase of IKAP, supporting a potential interaction between NOVA1 and IKAP. Taken together, these results reinforce the choice of miRNAs as potential therapeutic targets and suggest that NOVA1 could be a regulator of FD pathophysiology. Summary: A miRNA screening conducted in olfactory stem cells from patients links the neuron-specific splicing factor NOVA1 to neurodegeneration in familial dysautonomia.
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Affiliation(s)
- Mylène Hervé
- CRN2M-UMR7286, Aix-Marseille Université, CNRS, Faculté de Médecine Nord, Marseille 13344, Cedex 15, France
| | - El Chérif Ibrahim
- CRN2M-UMR7286, Aix-Marseille Université, CNRS, Faculté de Médecine Nord, Marseille 13344, Cedex 15, France
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Norcliffe-Kaufmann L, Slaugenhaupt SA, Kaufmann H. Familial dysautonomia: History, genotype, phenotype and translational research. Prog Neurobiol 2016; 152:131-148. [PMID: 27317387 DOI: 10.1016/j.pneurobio.2016.06.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/10/2016] [Accepted: 06/11/2016] [Indexed: 01/30/2023]
Abstract
Familial dysautonomia (FD) is a rare neurological disorder caused by a splice mutation in the IKBKAP gene. The mutation arose in the 1500s within the small Jewish founder population in Eastern Europe and became prevalent during the period of rapid population expansion within the Pale of Settlement. The carrier rate is 1:32 in Jews descending from this region. The mutation results in a tissue-specific deficiency in IKAP, a protein involved in the development and survival of neurons. Patients homozygous for the mutations are born with multiple lesions affecting mostly sensory (afferent) fibers, which leads to widespread organ dysfunction and increased mortality. Neurodegenerative features of the disease include progressive optic atrophy and worsening gait ataxia. Here we review the progress made in the last decade to better understand the genotype and phenotype. We also discuss the challenges of conducting controlled clinical trials in this rare medically fragile population. Meanwhile, the search for better treatments as well as a neuroprotective agent is ongoing.
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Affiliation(s)
| | - Susan A Slaugenhaupt
- Center for Human Genetic Research, Massachusetts General Hospital Research Institute and Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Horacio Kaufmann
- Department of Neurology, New York University School of Medicine, New York, NY, USA.
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