1
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Ou H, Wang L, Xi Z, Shen H, Jiang Y, Zhou F, Liu Y, Zhou Y. MYO10 contributes to the malignant phenotypes of colorectal cancer via RACK1 by activating integrin/Src/FAK signaling. Cancer Sci 2022; 113:3838-3851. [PMID: 35912545 DOI: 10.1111/cas.15519] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 07/13/2022] [Accepted: 07/20/2022] [Indexed: 11/28/2022] Open
Abstract
Liver metastases still remain a major cause of colorectal cancer (CRC) patient death. MYO10 is upregulated in several tumor types, however, its significance and the underlying mechanism in CRC is not entirely clear. Here we found that MYO10 was highly expressed in CRC tumor tissues, especially in liver metastasis tissues. MYO10 knockout reduced CRC cell proliferation, invasion, and migration in vitro, and CRC metastasis in vivo. We identified RACK1 by LC-MS/MS and demonstrated that MYO10 interacts with and stabilizes RACK1. Mechanistically, MYO10 promotes CRC cell progression and metastasis via ubiquitination-mediated RACK1 degradation and integrin/Src/FAK signaling activation. Therefore, the MYO10/RACK1/integrin/Src/FAK axis may play an important role in CRC progression and metastasis.
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Affiliation(s)
- Haibin Ou
- Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital, Wuhan University, Wuhan, China
| | - Lili Wang
- Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital, Wuhan University, Wuhan, China
| | - Ziyao Xi
- Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital, Wuhan University, Wuhan, China
| | - Hui Shen
- Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital, Wuhan University, Wuhan, China
| | - Yaofei Jiang
- Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital, Wuhan University, Wuhan, China
| | - Fuxiang Zhou
- Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital, Wuhan University, Wuhan, China
| | - Yu Liu
- Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital, Wuhan University, Wuhan, China
| | - Yunfeng Zhou
- Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Tumor Biological Behaviors, Zhongnan Hospital, Wuhan University, Wuhan, China
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2
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Li C, Zheng Y, Zheng Y, Xu Z. SRPS associated protein WDR60 regulates the multipolar-to-bipolar transition of migrating neurons during cortical development. Cell Death Dis 2021; 12:75. [PMID: 33436552 PMCID: PMC7804399 DOI: 10.1038/s41419-020-03363-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 12/12/2020] [Accepted: 12/17/2020] [Indexed: 11/17/2022]
Abstract
Mutations of WD40 repeat domain 60 (WDR60) have been identified in short-rib polydactyly syndromes (SRPS I–V), a group of lethal congenital disorders characterized by short ribs, polydactyly, and a range of extraskeletal phenotypes. However, the underlying mechanism is still unclear. Here, we report that WDR60 is essential for embryonic development and plays a critical role in the multipolar-bipolar transition and migration of newborn neurons during brain development. Mechanically, we found that WDR60 was located at the microtubule-organizing center to control microtubule organization and possibly, the trafficking of cellular components. Importantly, the migration defect caused by Wdr60 knockdown could be rescued by the stable form of α-Tubulin, α-TubulinK40Q (an acetylation-mimicking mutant). These findings identified a non-cilia function of WDR60 and provided insight into its biological function, as well as the pathogenesis of WDR60 deficiency associated with SRPS.
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Affiliation(s)
- Cui Li
- State Key Laboratory of Molecular Developmental Biology, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Yu Zheng
- State Key Laboratory of Molecular Developmental Biology, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Yufang Zheng
- Obstetrics & Gynecology Hospital, Institute of Reproduction & Development, Fudan University, Shanghai, 200011, China. .,Institute of Developmental Biology & Molecular Medicine, State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200433, China.
| | - Zhiheng Xu
- State Key Laboratory of Molecular Developmental Biology, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China. .,University of Chinese Academy of Sciences, Beijing, 100101, China. .,Parkinson's Disease Center, Beijing Institute for Brain Disorders, Beijing, 100053, China.
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3
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Xing ZK, Zhang LQ, Zhang Y, Sun X, Sun XL, Yu HL, Zheng YW, He ZX, Zhu XJ. DIP2B Interacts With α-Tubulin to Regulate Axon Outgrowth. Front Cell Neurosci 2020; 14:29. [PMID: 32153366 PMCID: PMC7045754 DOI: 10.3389/fncel.2020.00029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 01/31/2020] [Indexed: 01/14/2023] Open
Abstract
Axonal development is essential to the establishment of neuronal morphology and circuitry, although the mechanisms underlying axonal outgrowth during the early developmental stages remain unclear. Here, we showed that the conserved disco-interacting protein B (DIP2B) which consists of a DMAP1 domain and a crotonobetaine/carnitine CoA ligase (Caic) domain, is highly expressed in the excitatory neurons of the hippocampus. DIP2B knockout led to excessive axonal outgrowth but not polarity at an early developmental stage. Furthermore, the loss of DIP2B inhibited synaptic transmission for both spontaneous and rapid release in cultured hippocampal neurons. Interestingly, DIP2B function during axonal outgrowth requires tubulin acetylation. These findings reveal a new conserved regulator of neuronal morphology and provide a novel intervention mechanism for neurocognitive disorders.
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Affiliation(s)
- Zhen-Kai Xing
- Key Laboratory of Molecular Epigenetics Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, Changchun, China
| | - Lu-Qing Zhang
- Key Laboratory of Molecular Epigenetics Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, Changchun, China
| | - Yu Zhang
- Key Laboratory of Molecular Epigenetics Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, Changchun, China
| | - Xue Sun
- Key Laboratory of Molecular Epigenetics Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, Changchun, China
| | - Xiao-Lin Sun
- Key Laboratory of Molecular Epigenetics Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, Changchun, China
| | - Hua-Li Yu
- Key Laboratory of Molecular Epigenetics Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, Changchun, China
| | - Yao-Wu Zheng
- Key Laboratory of Molecular Epigenetics Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, Changchun, China
| | - Zi-Xuan He
- Key Laboratory of Molecular Epigenetics Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, Changchun, China
| | - Xiao-Juan Zhu
- Key Laboratory of Molecular Epigenetics Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, Changchun, China
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4
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Guo Y, Chen X, Xing R, Wang M, Zhu X, Guo W. Interplay between FMRP and lncRNA TUG1 regulates axonal development through mediating SnoN-Ccd1 pathway. Hum Mol Genet 2019; 27:475-485. [PMID: 29211876 DOI: 10.1093/hmg/ddx417] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 11/29/2017] [Indexed: 12/16/2022] Open
Abstract
LncRNAs have recently emerged to influence the pathogenesis of fragile X syndrome (FXS), which is caused by the functional loss of fragile X mental retardation protein (FMRP). However, the interaction between FMRP and lncRNAs on regulating neuronal development remains elusive. Here, we reported that FMRP directly interacted with lncRNA TUG1, and decreased its stability. Furthermore, TUG1 bond to transcriptional regulator, SnoN, and negatively modulated SnoN-Ccd1 pathway to specifically control axonal development. These observations suggested interplay between FMRP and lncRNAs might contribute to the pathogenesis of FXS.
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Affiliation(s)
- Ye Guo
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,Key Laboratory of Molecular Epigenetics, Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, Changchun 130024, China
| | - Xu Chen
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,Graduate School, University of Chinese Academy of Sciences, Beijing 100093, China
| | - Ruxiao Xing
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.,Graduate School, University of Chinese Academy of Sciences, Beijing 100093, China
| | - Min Wang
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaojuan Zhu
- Key Laboratory of Molecular Epigenetics, Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, Changchun 130024, China
| | - Weixiang Guo
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
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5
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Vuokila N, Lukasiuk K, Bot AM, van Vliet EA, Aronica E, Pitkänen A, Puhakka N. miR-124-3p is a chronic regulator of gene expression after brain injury. Cell Mol Life Sci 2018; 75:4557-4581. [PMID: 30155647 PMCID: PMC11105702 DOI: 10.1007/s00018-018-2911-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 08/02/2018] [Accepted: 08/22/2018] [Indexed: 02/06/2023]
Abstract
Traumatic brain injury (TBI) initiates molecular and cellular pathologies that underlie post-injury morbidities, including hippocampus-related memory decline and epileptogenesis. Non-coding small RNAs are master regulators of gene expression with the potential to affect multiple molecular pathways. To evaluate whether hippocampal gene expression networks are chronically regulated by microRNAs after TBI, we sampled the dentate gyrus of rats with severe TBI induced by lateral fluid-percussion injury 3 months earlier. Ingenuity pathway analysis revealed 30 upregulated miR-124-3p targets, suggesting that miR-124-3p is downregulated post-TBI (z-score = - 5.146, p < 0.05). Droplet digital polymerase chain reaction (ddPCR) and in situ hybridization confirmed the chronic downregulation of miR-124-3p (p < 0.05). Quantitative PCR analysis of two targets, Plp2 and Stat3, indicated that their upregulation correlated with the miR-124-3p downregulation (r = - 0.647, p < 0.05; r = - 0.629, p < 0.05, respectively). Immunohistochemical staining of STAT3 confirmed the increased protein expression. STRING analysis showed that 9 of the 30 miR-124-3p targets belonged to a STAT3 network. Reactome analysis and data mining connected the targets especially to inflammation and signal transduction. L1000CDS2 software revealed drugs (e.g., importazole, trichostatin A, and IKK-16) that could reverse the observed molecular changes. The translational value of our data was emphasized by in situ hybridization showing chronic post-traumatic downregulation of miR-124-3p in the dentate gyrus of TBI patients. Analysis of another brain injury model, status epilepticus, highlighted the fact that chronic downregulation of miR-124 is a common phenomenon after brain injury. Together, our findings indicate that miR-124-3p is a chronic modulator of molecular networks relevant to post-injury hippocampal pathologies in experimental models and in humans.
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Affiliation(s)
- Niina Vuokila
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, 70211, Kuopio, Finland
| | - Katarzyna Lukasiuk
- The Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Str, 02-093, Warsaw, Poland
| | - Anna Maria Bot
- The Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Str, 02-093, Warsaw, Poland
| | - Erwin A van Vliet
- Department of (Neuro)pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Eleonora Aronica
- Department of (Neuro)pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Amsterdam, The Netherlands
| | - Asla Pitkänen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, 70211, Kuopio, Finland.
| | - Noora Puhakka
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, 70211, Kuopio, Finland.
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6
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Abstract
Proper neuronal wiring is central to all bodily functions, sensory perception, cognition, memory, and learning. Establishment of a functional neuronal circuit is a highly regulated and dynamic process involving axonal and dendritic branching and navigation toward appropriate targets and connection partners. This intricate circuitry includes axo-dendritic synapse formation, synaptic connections formed with effector cells, and extensive dendritic arborization that function to receive and transmit mechanical and chemical sensory inputs. Such complexity is primarily achieved by extensive axonal and dendritic branch formation and pruning. Fundamental to neuronal branching are cytoskeletal dynamics and plasma membrane expansion, both of which are regulated via numerous extracellular and intracellular signaling mechanisms and molecules. This review focuses on recent advances in understanding the biology of neuronal branching.
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Affiliation(s)
- Shalini Menon
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Stephanie Gupton
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, Chapel Hill, NC, 27599, USA.,Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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7
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Guo Y, He X, Zhao L, Liu L, Song H, Wang X, Xu J, Ju X, Guo W, Zhu X. Gβ2 Regulates the Multipolar-Bipolar Transition of Newborn Neurons in the Developing Neocortex. Cereb Cortex 2018; 27:3414-3426. [PMID: 28334111 DOI: 10.1093/cercor/bhx042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Indexed: 01/14/2023] Open
Abstract
Proper neuronal migration is critical for the formation of the six-layered neocortex in the mammalian brain. However, the precise control of neuronal migration is not well understood. Heterotrimeric guanine nucleotide binding proteins (G proteins), composed of Gα and Gβγ, transduce signals from G protein-coupled receptors to downstream effectors and play crucial roles in brain development. However, the functions of individual subunits of G proteins in prenatal brain development remain unclear. Here, we report that Gβ2 is expressed in the embryonic neocortex, with abundant expression in the intermediate zone, and is significantly upregulated in differentiated neurons. Perturbation of Gβ2 expression impairs the morphogenetic transformation of migrating neurons from multipolar to bipolar and subsequently delays neuronal migration. Moreover, Gβ2 acts as a scaffold protein to organize the MP1-MEK1-ERK1/2 complex and mediates the phosphorylation of ERK1/2. Importantly, expression of a constitutively active variant of MEK1 rescues the migration defects that are caused by the loss of Gβ2. In conclusion, our findings reveal that Gβ2 regulates proper neuronal migration during neocortex development by activating the ERK1/2 signaling pathway.
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Affiliation(s)
- Ye Guo
- Key Laboratory of Molecular Epigenetics, Ministry of Education and Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China
| | - Xiaoxiao He
- Key Laboratory of Molecular Epigenetics, Ministry of Education and Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China
| | - Lu Zhao
- Key Laboratory of Molecular Epigenetics, Ministry of Education and Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China
| | - Lin Liu
- Key Laboratory of Molecular Epigenetics, Ministry of Education and Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China
| | - Huifang Song
- Key Laboratory of Molecular Epigenetics, Ministry of Education and Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China
| | - Xudong Wang
- Key Laboratory of Molecular Epigenetics, Ministry of Education and Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China
| | - Jiahui Xu
- Key Laboratory of Molecular Epigenetics, Ministry of Education and Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China
| | - Xingda Ju
- Key Laboratory of Molecular Epigenetics, Ministry of Education and Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China
| | - Weixiang Guo
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaojuan Zhu
- Key Laboratory of Molecular Epigenetics, Ministry of Education and Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China
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8
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Heimsath EG, Yim YI, Mustapha M, Hammer JA, Cheney RE. Myosin-X knockout is semi-lethal and demonstrates that myosin-X functions in neural tube closure, pigmentation, hyaloid vasculature regression, and filopodia formation. Sci Rep 2017; 7:17354. [PMID: 29229982 PMCID: PMC5725431 DOI: 10.1038/s41598-017-17638-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 11/28/2017] [Indexed: 01/07/2023] Open
Abstract
Myosin-X (Myo10) is an unconventional myosin best known for its striking localization to the tips of filopodia. Despite the broad expression of Myo10 in vertebrate tissues, its functions at the organismal level remain largely unknown. We report here the generation of KO-first (Myo10tm1a/tm1a), floxed (Myo10tm1c/tm1c), and KO mice (Myo10tm1d/tm1d). Complete knockout of Myo10 is semi-lethal, with over half of homozygous KO embryos exhibiting exencephaly, a severe defect in neural tube closure. All Myo10 KO mice that survive birth exhibit a white belly spot, all have persistent fetal vasculature in the eye, and ~50% have webbed digits. Myo10 KO mice that survive birth can breed and produce litters of KO embryos, demonstrating that Myo10 is not absolutely essential for mitosis, meiosis, adult survival, or fertility. KO-first mice and an independent spontaneous deletion (Myo10m1J/m1J) exhibit the same core phenotypes. During retinal angiogenesis, KO mice exhibit a ~50% decrease in endothelial filopodia, demonstrating that Myo10 is required to form normal numbers of filopodia in vivo. The Myo10 mice generated here demonstrate that Myo10 has important functions in mammalian development and provide key tools for defining the functions of Myo10 in vivo.
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Affiliation(s)
- Ernest G Heimsath
- Department of Cell Biology and Physiology and Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Yang-In Yim
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Mirna Mustapha
- Department of Otolaryngology, Stanford University School of Medicine, Palo Alto, CA, 94305, USA
| | - John A Hammer
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Richard E Cheney
- Department of Cell Biology and Physiology and Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA. .,Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
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9
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O'Connor E, Töpf A, Müller JS, Cox D, Evangelista T, Colomer J, Abicht A, Senderek J, Hasselmann O, Yaramis A, Laval SH, Lochmüller H. Identification of mutations in the MYO9A gene in patients with congenital myasthenic syndrome. Brain 2016; 139:2143-53. [PMID: 27259756 PMCID: PMC4958899 DOI: 10.1093/brain/aww130] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 04/20/2016] [Indexed: 12/13/2022] Open
Abstract
Congenital myasthenic syndromes are a group of rare and genetically heterogenous disorders resulting from defects in the structure and function of the neuromuscular junction. Patients with congenital myasthenic syndrome exhibit fatigable muscle weakness with a variety of accompanying phenotypes depending on the protein affected. A cohort of patients with a clinical diagnosis of congenital myasthenic syndrome that lacked a genetic diagnosis underwent whole exome sequencing in order to identify genetic causation. Missense biallelic mutations in the MYO9A gene, encoding an unconventional myosin, were identified in two unrelated families. Depletion of MYO9A in NSC-34 cells revealed a direct effect of MYO9A on neuronal branching and axon guidance. Morpholino-mediated knockdown of the two MYO9A orthologues in zebrafish, myo9aa/ab, demonstrated a requirement for MYO9A in the formation of the neuromuscular junction during development. The morphants displayed shortened and abnormally branched motor axons, lack of movement within the chorion and abnormal swimming in response to tactile stimulation. We therefore conclude that MYO9A deficiency may affect the presynaptic motor axon, manifesting in congenital myasthenic syndrome. These results highlight the involvement of unconventional myosins in motor axon functionality, as well as the need to look outside traditional neuromuscular junction-specific proteins for further congenital myasthenic syndrome candidate genes.
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Affiliation(s)
- Emily O'Connor
- 1 John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| | - Ana Töpf
- 1 John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| | - Juliane S Müller
- 2 Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Daniel Cox
- 1 John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| | - Teresinha Evangelista
- 1 John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| | - Jaume Colomer
- 3 Neuromuscular Unit, Neurology Department, Fundación Sant Joan de Déu, Hospital Materno-Infantil Sant Joan de Déu, Passeig Sant Joan de Déu, 2, 08950 Esplugues de Llobregat, Barcelona, Spain
| | - Angela Abicht
- 4 Friedrich-Baur-Institute, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Jan Senderek
- 4 Friedrich-Baur-Institute, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Oswald Hasselmann
- 5 Children's Hospital of Eastern Switzerland, Department of Neuropediatrics, Claudiusstrasse 6, 9006 St. Gallen, Switzerland
| | - Ahmet Yaramis
- 6 Paediatric Neurology Unit, Diyarbakır Memorial Hospital, Turkey
| | - Steven H Laval
- 1 John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
| | - Hanns Lochmüller
- 1 John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
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