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Schultz A, Albertos-Arranz H, Sáez XS, Morgan J, Darland DC, Gonzalez-Duarte A, Kaufmann H, Mendoza-Santiesteban CE, Cuenca N, Lefcort F. Neuronal and glial cell alterations involved in the retinal degeneration of the familial dysautonomia optic neuropathy. Glia 2024. [PMID: 39228100 DOI: 10.1002/glia.24612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 07/27/2024] [Accepted: 08/19/2024] [Indexed: 09/05/2024]
Abstract
Familial dysautonomia (FD) is a rare genetic neurodevelopmental and neurodegenerative disorder. In addition to the autonomic and peripheral sensory neuropathies that challenge patient survival, one of the most debilitating symptoms affecting patients' quality of life is progressive blindness resulting from the steady loss of retinal ganglion cells (RGCs). Within the FD community, there is a concerted effort to develop treatments to prevent the loss of RGCs. However, the mechanisms underlying the death of RGCs are not well understood. To study the mechanisms underlying RGC death, Pax6-cre;Elp1loxp/loxp male and female mice and postmortem retinal tissue from an FD patient were used to explore the neuronal and non-neuronal cellular pathology associated with the FD optic neuropathy. Neurons, astrocytes, microglia, Müller glia, and endothelial cells were investigated using a combination of histological analyses. We identified a novel disruption of cellular homeostasis and gliosis in the FD retina. Beginning shortly after birth and progressing with age, the FD retina is marked by astrogliosis and perturbations in microglia, which coincide with vascular remodeling. These changes begin before the onset of RGC death, suggesting alterations in the retinal neurovascular unit may contribute to and exacerbate RGC death. We reveal for the first time that the FD retina pathology includes reactive gliosis, increased microglial recruitment to the ganglion cell layer (GCL), disruptions in the deep and superficial vascular plexuses, and alterations in signaling pathways. These studies implicate the neurovascular unit as a disease-modifying target for therapeutic interventions in FD.
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Affiliation(s)
- Anastasia Schultz
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Henar Albertos-Arranz
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Xavier Sánchez Sáez
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Jamie Morgan
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Diane C Darland
- Department of Biology, University of North Dakota, Grand Forks, North Dakota, USA
| | | | - Horacio Kaufmann
- Department of Neurology, NYU Langone Health, New York, New York, USA
| | - Carlos E Mendoza-Santiesteban
- Department of Neurology, NYU Langone Health, New York, New York, USA
- Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA
| | - Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Frances Lefcort
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
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Halmi C, Leonard CE, McIntosh A, Taneyhill L. N-cadherin facilitates trigeminal sensory neuron outgrowth and target tissue innervation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.20.594965. [PMID: 38826314 PMCID: PMC11142107 DOI: 10.1101/2024.05.20.594965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
During embryonic development, diverse cell types coordinate to form functionally complex tissues. Exemplifying this process, the trigeminal ganglion emerges from the condensation of two distinct precursor cell populations, cranial placodes and neural crest, with neuronal differentiation of the former preceding the latter. While its dual cellular origin has been understood for decades, the molecules orchestrating trigeminal ganglion formation remain relatively obscure. Initial assembly of the trigeminal ganglion is mediated by cell adhesion molecules, including neural cadherin (N-cadherin), which is first expressed by placodal neurons and is required for their proper condensation with other neurons and neural crest cells. Axon outgrowth first occurs from placodal neurons, but as gangliogenesis proceeds, neural crest cells also differentiate into N-cadherin-expressing neurons, and together both extend axons toward target tissues. However, a role for N-cadherin in regulating axon outgrowth and innervation of target tissues by trigeminal neurons has not been explored. To this end, we depleted N-cadherin from chick trigeminal placode cells and observed decreases in trigeminal ganglion size, nerve growth, and target innervation in vivo, phenotypes that could only partially be attributed to increased apoptosis early in gangliogenesis. Accordingly, neurite number and branching of neural crest-derived neurons was decreased in vitro in response to N-cadherin knockdown in placode cells, providing a novel non-cell autonomous explanation for these morphological changes. Inhibiting N-cadherin-mediated adhesion with a function-blocking antibody prevented axon extension in most, but not all, placode-derived trigeminal neurons in vitro, indicating potential unique requirements for N-cadherin in various neuronal subtypes. Collectively, these findings reveal persistent cell autonomous and non-cell autonomous functions for N-cadherin, thus highlighting the critical role of N-cadherin in mediating reciprocal interactions between neural crest and placode neuronal derivatives during trigeminal ganglion development.
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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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Leonard CE, McIntosh A, Taneyhill LA. The transcriptional landscape of the developing chick trigeminal ganglion. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.20.604400. [PMID: 39211243 PMCID: PMC11361123 DOI: 10.1101/2024.07.20.604400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
The trigeminal ganglion is a critical structure in the peripheral nervous system, responsible for transmitting sensations of touch, pain, and temperature from craniofacial regions to the brain. Trigeminal ganglion development depends upon intrinsic cellular programming as well as extrinsic signals exchanged by diverse cell populations. With its complex anatomy and dual cellular origin from cranial placodes and neural crest cells, the trigeminal ganglion offers a rich context for examining diverse biological processes, including cell migration, fate determination, adhesion, and axon guidance. Avian models have, so far, enabled key insights into craniofacial and peripheral nervous system development. Yet, the molecular mechanisms driving trigeminal ganglion formation and subsequent nerve growth remain elusive. In this study, we performed RNA-sequencing at multiple stages of chick trigeminal ganglion development and generated a novel transcriptomic dataset that has been curated to illustrate temporally dynamic gene expression patterns. This publicly available resource identifies major pathways involved in trigeminal gangliogenesis, particularly with respect to the condensation and maturation of placode-derived neurons, thus inviting new lines of research into the essential processes governing trigeminal ganglion development.
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Hines MA, Taneyhill LA. Elp1 function in placode-derived neurons is critical for proper trigeminal ganglion development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.12.603323. [PMID: 39071383 PMCID: PMC11275904 DOI: 10.1101/2024.07.12.603323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Background The trigeminal nerve is the largest cranial nerve and functions in somatosensation. Cell bodies of this nerve are positioned in the trigeminal ganglion, which arises from the coalescence of neural crest and placode cells. While this dual cellular origin has been known for decades, the molecular mechanisms controlling trigeminal ganglion development remain obscure. We performed RNAsequencing on the forming chick trigeminal ganglion and identified Elongator acetyltransferase complex subunit 1 ( Elp1 ) for further study. Mutations in ELP1 cause familial dysautonomia (FD), a fatal disorder characterized by the presence of smaller trigeminal nerves and sensory deficits. While Elp1 has established roles in neurogenesis, its functions in placode cells during trigeminal gangliogenesis have not been investigated. Results To this end, we used morpholinos to deplete Elp1 from chick trigeminal placode cells. Elp1 knockdown decreased trigeminal ganglion size and led to aberrant innervation of the eye by placode-derived neurons. Trigeminal nerve branches exhibited fewer axons, and abnormal interactions between placode-derived neurons and neural crest cells were observed. Conclusions These findings reveal a new role for Elp1 in chick placode-derived neurons during trigeminal ganglion development. These results have potential high significance to provide new insights into trigeminal ganglion development and the etiology of FD. Bullet points Elp1 is expressed in undifferentiated neural crest cells and placode-derived neurons contributing to the trigeminal ganglion.Elp1 knockdown in trigeminal placode cells reduces trigeminal ganglion size.Elp1 depletion from trigeminal placode cells leads to aberrant target tissue innervation and disrupts proper neural crest-placodal neuron interactions in the trigeminal ganglion. Grant sponsor and number NIH R01DE024217 and NIH R03HD108480.
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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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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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