1
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Esposito A, Pepe S, Cerullo MS, Cortese K, Semini HT, Giovedì S, Guerrini R, Benfenati F, Falace A, Fassio A. ATP6V1A is required for synaptic rearrangements and plasticity in murine hippocampal neurons. Acta Physiol (Oxf) 2024:e14186. [PMID: 38837572 DOI: 10.1111/apha.14186] [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: 09/11/2023] [Revised: 05/05/2024] [Accepted: 05/23/2024] [Indexed: 06/07/2024]
Abstract
AIM Understanding the physiological role of ATP6V1A, a component of the cytosolic V1 domain of the proton pump vacuolar ATPase, in regulating neuronal development and function. METHODS Modeling loss of function of Atp6v1a in primary murine hippocampal neurons and studying neuronal morphology and function by immunoimaging, electrophysiological recordings and electron microscopy. RESULTS Atp6v1a depletion affects neurite elongation, stabilization, and function of excitatory synapses and prevents synaptic rearrangement upon induction of plasticity. These phenotypes are due to an overall decreased expression of the V1 subunits, that leads to impairment of lysosomal pH-regulation and autophagy progression with accumulation of aberrant lysosomes at neuronal soma and of enlarged vacuoles at synaptic boutons. CONCLUSIONS These data suggest a physiological role of ATP6V1A in the surveillance of synaptic integrity and plasticity and highlight the pathophysiological significance of ATP6V1A loss in the alteration of synaptic function that is associated with neurodevelopmental and neurodegenerative diseases. The data further support the pivotal involvement of lysosomal function and autophagy flux in maintaining proper synaptic connectivity and adaptive neuronal properties.
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Affiliation(s)
| | - Sara Pepe
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
- IRCCS, Ospedale Policlinico San Martino, Genoa, Italy
| | - Maria Sabina Cerullo
- Center for Synaptic Neuroscience and Technology, Italian Institute of Technology, Genoa, Italy
| | - Katia Cortese
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | | | - Silvia Giovedì
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
- IRCCS, Ospedale Policlinico San Martino, Genoa, Italy
| | - Renzo Guerrini
- Children's Hospital A. Meyer IRCCS, Florence, Italy
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, University of Florence, Florence, Italy
| | - Fabio Benfenati
- IRCCS, Ospedale Policlinico San Martino, Genoa, Italy
- Center for Synaptic Neuroscience and Technology, Italian Institute of Technology, Genoa, Italy
| | - Antonio Falace
- Children's Hospital A. Meyer IRCCS, Florence, Italy
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto "Giannina Gaslini", Genoa, Italy
| | - Anna Fassio
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
- IRCCS, Ospedale Policlinico San Martino, Genoa, Italy
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2
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Petrauskas A, Fortunati DL, Kandi AR, Pothapragada SS, Agrawal K, Singh A, Huelsmeier J, Hillebrand J, Brown G, Chaturvedi D, Lee J, Lim C, Auburger G, VijayRaghavan K, Ramaswami M, Bakthavachalu B. Structured and disordered regions of Ataxin-2 contribute differently to the specificity and efficiency of mRNP granule formation. PLoS Genet 2024; 20:e1011251. [PMID: 38768217 PMCID: PMC11166328 DOI: 10.1371/journal.pgen.1011251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 06/11/2024] [Accepted: 04/05/2024] [Indexed: 05/22/2024] Open
Abstract
Ataxin-2 (ATXN2) is a gene implicated in spinocerebellar ataxia type II (SCA2), amyotrophic lateral sclerosis (ALS) and Parkinsonism. The encoded protein is a therapeutic target for ALS and related conditions. ATXN2 (or Atx2 in insects) can function in translational activation, translational repression, mRNA stability and in the assembly of mRNP-granules, a process mediated by intrinsically disordered regions (IDRs). Previous work has shown that the LSm (Like-Sm) domain of Atx2, which can help stimulate mRNA translation, antagonizes mRNP-granule assembly. Here we advance these findings through a series of experiments on Drosophila and human Ataxin-2 proteins. Results of Targets of RNA Binding Proteins Identified by Editing (TRIBE), co-localization and immunoprecipitation experiments indicate that a polyA-binding protein (PABP) interacting, PAM2 motif of Ataxin-2 may be a major determinant of the mRNA and protein content of Ataxin-2 mRNP granules. Experiments with transgenic Drosophila indicate that while the Atx2-LSm domain may protect against neurodegeneration, structured PAM2- and unstructured IDR- interactions both support Atx2-induced cytotoxicity. Taken together, the data lead to a proposal for how Ataxin-2 interactions are remodelled during translational control and how structured and non-structured interactions contribute differently to the specificity and efficiency of RNP granule condensation as well as to neurodegeneration.
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Affiliation(s)
- Arnas Petrauskas
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Daniel L. Fortunati
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Arvind Reddy Kandi
- School of Biosciences and Bioengineering, Indian Institute of Technology, Mandi, India
| | | | - Khushboo Agrawal
- Tata Institute for Genetics and Society Centre at inStem, Bellary Road, Bangalore, India
- School of Biotechnology, Amrita Vishwa Vidyapeetham University, Kollam, Kerala, India
| | - Amanjot Singh
- National Centre for Biological Sciences, TIFR, Bangalore, India
- Manipal Institute of Regenerative Medicine, MAHE-Bengaluru, Govindapura, Bengaluru, India
| | - Joern Huelsmeier
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Jens Hillebrand
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Georgia Brown
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | | | - Jongbo Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan, Republic of Korea
| | - Chunghun Lim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan, Republic of Korea
| | - Georg Auburger
- Experimental Neurology, Medical School, Goethe University, Frankfurt, Germany
| | | | - Mani Ramaswami
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
- National Centre for Biological Sciences, TIFR, Bangalore, India
| | - Baskar Bakthavachalu
- School of Biosciences and Bioengineering, Indian Institute of Technology, Mandi, India
- Tata Institute for Genetics and Society Centre at inStem, Bellary Road, Bangalore, India
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3
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Guo B, Li QY, Liu XJ, Luo GH, Wu YJ, Nie J. Diabetes mellitus and Alzheimer's disease: Vacuolar adenosine triphosphatase as a potential link. Eur J Neurosci 2024; 59:2577-2595. [PMID: 38419188 DOI: 10.1111/ejn.16286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/01/2024] [Accepted: 02/02/2024] [Indexed: 03/02/2024]
Abstract
Globally, the incidence of diabetes mellitus (DM) and Alzheimer's disease (AD) is increasing year by year, causing a huge economic and social burden, and their pathogenesis and aetiology have been proven to have a certain correlation. In recent years, more and more studies have shown that vacuolar adenosine triphosphatases (v-ATPases) in eukaryotes, which are biomolecules regulating lysosomal acidification and glycolipid metabolism, play a key role in DM and AD. This article describes the role of v-ATPase in DM and AD, including its role in glycolysis, insulin secretion and insulin resistance (IR), as well as its relationship with lysosomal acidification, autophagy and β-amyloid (Aβ). In DM, v-ATPase is involved in the regulation of glucose metabolism and IR. v-ATPase is closely related to glycolysis. On the one hand, v-ATPase affects the rate of glycolysis by affecting the secretion of insulin and changing the activities of key glycolytic enzymes hexokinase (HK) and phosphofructokinase 1 (PFK-1). On the other hand, glucose is the main regulator of this enzyme, and the assembly and activity of v-ATPase depend on glucose, and glucose depletion will lead to its decomposition and inactivation. In addition, v-ATPase can also regulate free fatty acids, thereby improving IR. In AD, v-ATPase can not only improve the abnormal brain energy metabolism by affecting lysosomal acidification and autophagy but also change the deposition of Aβ by affecting the production and degradation of Aβ. Therefore, v-ATPase may be the bridge between DM and AD.
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Affiliation(s)
- Bin Guo
- Key Laboratory of Basic Pharmacology of the Ministry of Education and Joint International Research Laboratory of Ethnomedicine of the Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China
| | - Qi-Ye Li
- Key Laboratory of Basic Pharmacology of the Ministry of Education and Joint International Research Laboratory of Ethnomedicine of the Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China
| | - Xue-Jia Liu
- Key Laboratory of Basic Pharmacology of the Ministry of Education and Joint International Research Laboratory of Ethnomedicine of the Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China
| | - Guo-Hui Luo
- Key Laboratory of Basic Pharmacology of the Ministry of Education and Joint International Research Laboratory of Ethnomedicine of the Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China
| | - Ya-Juan Wu
- Key Laboratory of Basic Pharmacology of the Ministry of Education and Joint International Research Laboratory of Ethnomedicine of the Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China
| | - Jing Nie
- Key Laboratory of Basic Pharmacology of the Ministry of Education and Joint International Research Laboratory of Ethnomedicine of the Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China
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4
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Chen L, Chen G, Zhang M, Zhang X. Modeling sporadic juvenile ALS in iPSC-derived motor neurons explores the pathogenesis of FUS R503fs mutation. Front Cell Neurosci 2024; 18:1364164. [PMID: 38711616 PMCID: PMC11070534 DOI: 10.3389/fncel.2024.1364164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Accepted: 03/26/2024] [Indexed: 05/08/2024] Open
Abstract
Introduction Fused in sarcoma (FUS) mutations represent the most common genetic etiology of juvenile amyotrophic lateral sclerosis (JALS), for which effective treatments are lacking. In a prior report, we identified a novel FUS mutation, c.1509dupA: p. R503fs (FUSR503fs), in a sporadic JALS patient. Methods The physicochemical properties and structure of FUSR503fs protein were analyzed by software: Multi-electrode array (MEA) assay, calcium activity imaging assay and transcriptome analysis were used to explore the pathophysiological mechanism of iPSC derived motor neurons. Results Structural analysis and predictions regarding physical and chemical properties of this mutation suggest that the reduction of phosphorylation and glycosylation sites, along with alterations in the amino acid sequence, may contribute to abnormal FUS accumulation within the cytoplasm and nucleus of induced pluripotent stem cell- derived motor neurons (MNs). Multi-electrode array and calcium activity imaging indicate diminished spontaneous electrical and calcium activity signals in MNs harboring the FUSR503fs mutation. Transcriptomic analysis reveals upregulation of genes associated with viral infection and downregulation of genes involved in neural function maintenance, such as the ATP6V1C2 gene. Treatment with ropinirole marginally mitigates the electrophysiological decline in FUSR503fs MNs, suggesting the utility of this cell model for mechanistic exploration and drug screening. Discussion iPSCs-derived motor neurons from JALS patients are promising tools for drug screening. The pathological changes in motor neurons of FUSR503fs may occur earlier than in other known mutation types that have been reported.
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Affiliation(s)
- Li Chen
- Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Neurological Rare Disease Biobank and Precision Diagnostic Technical Service Platform, Shanghai, China
| | - Guojie Chen
- Hunan YoBon Biotechnology Limited Company, Changsha, Hunan, China
| | - Mengting Zhang
- College of Integrated Chinese and Western Medicine (School of Life Sciences), Anhui University of Chinese Medicine, Hefei, Anhui, China
| | - Xiaojie Zhang
- Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Neurological Rare Disease Biobank and Precision Diagnostic Technical Service Platform, Shanghai, China
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5
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Ferrari V, Conti M, Bovenzi R, Cerroni R, Pierantozzi M, Mercuri NB, Stefani A. Rare association between spinocerebellar ataxia and amyotrophic lateral sclerosis: a case series. Neurol Sci 2024:10.1007/s10072-024-07521-9. [PMID: 38642323 DOI: 10.1007/s10072-024-07521-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/08/2024] [Indexed: 04/22/2024]
Abstract
INTRODUCTION In this work, we describe a new case of association between SCA2 and MND. CASE REPORT A 58-year-old man who was diagnosed with spinocerebellar ataxia type 2 presented dysphagia and a significant decline in his ability to walk, with a reduction in autonomy and the need to use a wheelchair. We performed electromyography and electroneurography of the four limbs and of the cranial district and motor-evoked potentials to study upper and lower motor neurons. Referring to the revised El Escorial criteria of 2015, ALS diagnosis was made. DISCUSSION Considering different cases described in literature over the years, SCA2 could represent an important risk factor for developing ALS. In particular, the presence of alleles of ATXN2 with 27 and 28 CAG repeats seems to slightly decrease the risk of developing the disease, which would instead be progressively increased by the presence of alleles with 29, 30, 31, 32, and 33 repeats. The exact physiopathological mechanism by which the mutation increases the risk of developing the disease is currently unknown. Transcriptomic studies on mouse models have demonstrated the involvement of several pathways, including the innate immunity regulation by STING and the biosynthesis of fatty acid and cholesterol by SREBP. CONCLUSION CAG repeat expansions in the ATXN2 gene have been associated with variable neurological presentations, which include SCA2, ALS, Parkinsonism, or a combination of them. Further research is needed to understand the relationship between SCA2 and ALS better and explore molecular underlying mechanisms.
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Affiliation(s)
- Valerio Ferrari
- Parkinson Centre, Department of Systems Medicine, University of Rome "Tor Vergata,", Rome, Italy
| | - Matteo Conti
- Parkinson Centre, Department of Systems Medicine, University of Rome "Tor Vergata,", Rome, Italy
| | - Roberta Bovenzi
- Parkinson Centre, Department of Systems Medicine, University of Rome "Tor Vergata,", Rome, Italy
| | - Rocco Cerroni
- Parkinson Centre, Department of Systems Medicine, University of Rome "Tor Vergata,", Rome, Italy
| | - Mariangela Pierantozzi
- Neurology Unit, Department of Systems Medicine, University of Rome "Tor Vergata,", Rome, Italy
| | - Nicola B Mercuri
- Neurology Unit, Department of Systems Medicine, University of Rome "Tor Vergata,", Rome, Italy
| | - Alessandro Stefani
- Parkinson Centre, Department of Systems Medicine, University of Rome "Tor Vergata,", Rome, Italy.
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6
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Kramer NJ, Prakash G, Isaac RS, Choquet K, Soto I, Petrova B, Merens HE, Kanarek N, Churchman LS. Regulators of mitonuclear balance link mitochondrial metabolism to mtDNA expression. Nat Cell Biol 2023; 25:1575-1589. [PMID: 37770567 DOI: 10.1038/s41556-023-01244-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 08/29/2023] [Indexed: 09/30/2023]
Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) complexes are assembled from proteins encoded by both nuclear and mitochondrial DNA. These dual-origin enzymes pose a complex gene regulatory challenge for cells requiring coordinated gene expression across organelles. To identify genes involved in dual-origin protein complex synthesis, we performed fluorescence-activated cell-sorting-based genome-wide screens analysing mutant cells with unbalanced levels of mitochondrial- and nuclear-encoded subunits of Complex IV. We identified genes involved in OXPHOS biogenesis, including two uncharacterized genes: PREPL and NME6. We found that PREPL specifically impacts Complex IV biogenesis by acting at the intersection of mitochondrial lipid metabolism and protein synthesis, whereas NME6, an uncharacterized nucleoside diphosphate kinase, controls OXPHOS biogenesis through multiple mechanisms reliant on its NDPK domain. Firstly, NME6 forms a complex with RCC1L, which together perform nucleoside diphosphate kinase activity to maintain local mitochondrial pyrimidine triphosphate levels essential for mitochondrial RNA abundance. Secondly, NME6 modulates the activity of mitoribosome regulatory complexes, altering mitoribosome assembly and mitochondrial RNA pseudouridylation. Taken together, we propose that NME6 acts as a link between compartmentalized mitochondrial metabolites and mitochondrial gene expression.
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Affiliation(s)
- Nicholas J Kramer
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Gyan Prakash
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - R Stefan Isaac
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Karine Choquet
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Iliana Soto
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Boryana Petrova
- Department of Pathology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Hope E Merens
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Naama Kanarek
- Department of Pathology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - L Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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7
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Riepe C, Wąchalska M, Deol KK, Amaya AK, Porteus MH, Olzmann JA, Kopito RR. Small molecule correctors divert CFTR-F508del from ERAD by stabilizing sequential folding states. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.15.556420. [PMID: 37745470 PMCID: PMC10515913 DOI: 10.1101/2023.09.15.556420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Over 80% of people with cystic fibrosis (CF) carry the F508del mutation in the cystic fibrosis transmembrane conductance regulator (CFTR), a chloride ion channel at the apical plasma membrane (PM) of epithelial cells. F508del impairs CFTR folding causing it to be destroyed by endoplasmic reticulum associated degradation (ERAD). Small molecule correctors, which act as pharmacological chaperones to divert CFTR-F508del from ERAD, are the primary strategy for treating CF, yet corrector development continues with only a rudimentary understanding of how ERAD targets CFTR-F508del. We conducted genome-wide CRISPR/Cas9 knockout screens to systematically identify the molecular machinery that underlies CFTR-F508del ERAD. Although the ER-resident ubiquitin ligase, RNF5 was the top E3 hit, knocking out RNF5 only modestly reduced CFTR-F508del degradation. Sublibrary screens in an RNF5 knockout background identified RNF185 as a redundant ligase, demonstrating that CFTR-F508del ERAD is highly buffered. Gene-drug interaction experiments demonstrated that correctors tezacaftor (VX-661) and elexacaftor (VX-445) stabilize sequential, RNF5-resistant folding states. We propose that binding of correctors to nascent CFTR-F508del alters its folding landscape by stabilizing folding states that are not substrates for RNF5-mediated ubiquitylation.
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Affiliation(s)
- Celeste Riepe
- Department of Biology, Stanford University, Stanford, CA, USA 94305
| | - Magda Wąchalska
- Department of Biology, Stanford University, Stanford, CA, USA 94305
| | - Kirandeep K. Deol
- Department of Molecular and Cell Biology, University of California, Berkeley, CA USA 94720
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA USA 94720
- Chan Zuckerberg Biohub, San Francisco, CA, USA 94158
| | - Anais K. Amaya
- Department of Pediatrics, Stanford University, Stanford, CA, USA 94305
| | | | - James A. Olzmann
- Department of Molecular and Cell Biology, University of California, Berkeley, CA USA 94720
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA USA 94720
- Chan Zuckerberg Biohub, San Francisco, CA, USA 94158
| | - Ron R. Kopito
- Department of Biology, Stanford University, Stanford, CA, USA 94305
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8
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Lu J, Li Z, Gitler AD, Lu B. Drugging "undruggable" neurodegenerative disease targets with small molecules. Sci Bull (Beijing) 2023; 68:1715-1718. [PMID: 37468412 DOI: 10.1016/j.scib.2023.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Affiliation(s)
- Junmei Lu
- Neurology Department at Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, New Cornerstone Science Laboratory, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Zhaoyang Li
- Neurology Department at Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, New Cornerstone Science Laboratory, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Aaron D Gitler
- Department of Genetics, Stanford University, Stanford, CA 94305, USA; Chan Zuckerberg Biohub-San Francisco, San Francisco, CA 94158, USA.
| | - Boxun Lu
- Neurology Department at Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, New Cornerstone Science Laboratory, School of Life Sciences, Fudan University, Shanghai 200438, China.
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9
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Egorova PA, Marinina KS, Bezprozvanny IB. Chronic suppression of STIM1-mediated calcium signaling in Purkinje cells rescues the cerebellar pathology in spinocerebellar ataxia type 2. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119466. [PMID: 36940741 DOI: 10.1016/j.bbamcr.2023.119466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 03/10/2023] [Accepted: 03/14/2023] [Indexed: 03/23/2023]
Abstract
Distorted neuronal calcium signaling has been reported in many neurodegenerative disorders, including different types of spinocerebellar ataxias (SCAs). Cerebellar Purkinje cells (PCs) are primarily affected in SCAs and the disturbances in the calcium homeostasis were observed in SCA PCs. Our previous results have revealed that 3,5-dihydroxyphenylglycine (DHPG) induced greater calcium responses in SCA2-58Q PC cultures than in wild type (WT) PC cultures. Here we observed that glutamate-induced calcium release in PCs cells bodies is significantly higher in SCA2-58Q PCs from acute cerebellar slices compared to WT PCs of the same age. Recent studies have demonstrated that the stromal interaction molecule 1 (STIM1) plays an important role in the regulation of the neuronal calcium signaling in cerebellar PCs in mice. The main function of STIM1 is to regulate store-operated calcium entry through the TRPC/Orai channels formation to refill the calcium stores in the ER when it is empty. Here we demonstrated that the chronic viral-mediated expression of the small interfering RNA (siRNA) targeting STIM1 specifically in cerebellar PCs alleviates the deranged calcium signaling in SCA2-58Q PCs, rescues the spine loss in these cerebellar neurons, and also improves the motor decline in SCA2-58Q mice. Thus, our preliminary results support the important role of the altered neuronal calcium signaling in SCA2 pathology and also suggest the STIM1-mediated signaling pathway as a potential therapeutic target for treatment of SCA2 patients.
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Affiliation(s)
- Polina A Egorova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Ksenia S Marinina
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Ilya B Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia; Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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10
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Kramer NJ, Prakash G, Choquet K, Soto I, Petrova B, Merens HE, Kanarek N, Churchman LS. Genome-wide screens for mitonuclear co-regulators uncover links between compartmentalized metabolism and mitochondrial gene expression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.11.528118. [PMID: 36798306 PMCID: PMC9934615 DOI: 10.1101/2023.02.11.528118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) complexes are assembled from proteins encoded by both nuclear and mitochondrial DNA. These dual-origin enzymes pose a complex gene regulatory challenge for cells, in which gene expression must be coordinated across organelles using distinct pools of ribosomes. How cells produce and maintain the accurate subunit stoichiometries for these OXPHOS complexes remains largely unknown. To identify genes involved in dual-origin protein complex synthesis, we performed FACS-based genome-wide screens analyzing mutant cells with unbalanced levels of mitochondrial- and nuclear-encoded subunits of cytochrome c oxidase (Complex IV). We identified novel genes involved in OXPHOS biogenesis, including two uncharacterized genes: PREPL and NME6 . We found that PREPL specifically regulates Complex IV biogenesis by interacting with mitochondrial protein synthesis machinery, while NME6, an uncharacterized nucleoside diphosphate kinase (NDPK), controls OXPHOS complex biogenesis through multiple mechanisms reliant on its NDPK domain. First, NME6 maintains local mitochondrial pyrimidine triphosphate levels essential for mitochondrial RNA abundance. Second, through stabilizing interactions with RCC1L, NME6 modulates the activity of mitoribosome regulatory complexes, leading to disruptions in mitoribosome assembly and mitochondrial RNA pseudouridylation. Taken together, we propose that NME6 acts as a link between compartmentalized mitochondrial metabolites and mitochondrial gene expression. Finally, we present these screens as a resource, providing a catalog of genes involved in mitonuclear gene regulation and OXPHOS biogenesis.
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11
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Rodriguez CM, Bechek SC, Jones GL, Nakayama L, Akiyama T, Kim G, Solow-Cordero DE, Strittmatter SM, Gitler AD. Targeting RTN4/NoGo-Receptor reduces levels of ALS protein ataxin-2. Cell Rep 2022; 41:111505. [PMID: 36288715 PMCID: PMC9664481 DOI: 10.1016/j.celrep.2022.111505] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 05/30/2022] [Accepted: 09/22/2022] [Indexed: 01/27/2023] Open
Abstract
Gene-based therapeutic strategies to lower ataxin-2 levels are emerging for the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and spinocerebellar ataxia type 2 (SCA2). Additional strategies to lower levels of ataxin-2 could be beneficial. Here, we perform a genome-wide arrayed small interfering RNA (siRNA) screen in human cells and identify RTN4R, the gene encoding the RTN4/NoGo-Receptor, as a potent modifier of ataxin-2 levels. RTN4R knockdown, or treatment with a peptide inhibitor, is sufficient to lower ataxin-2 protein levels in mouse and human neurons in vitro, and Rtn4r knockout mice have reduced ataxin-2 levels in vivo. We provide evidence that ataxin-2 shares a role with the RTN4/NoGo-Receptor in limiting axonal regeneration. Reduction of either protein increases axonal regrowth following axotomy. These data define the RTN4/NoGo-Receptor as a novel therapeutic target for ALS and SCA2 and implicate the targeting of ataxin-2 as a potential treatment following nerve injury.
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Affiliation(s)
- Caitlin M Rodriguez
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sophia C Bechek
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Graham L Jones
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Lisa Nakayama
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tetsuya Akiyama
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Garam Kim
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA; Stanford Neurosciences Interdepartmental Program, Stanford University School of Medicine, Stanford, CA, USA
| | - David E Solow-Cordero
- High-Throughput Bioscience Center, Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Stephen M Strittmatter
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT, USA
| | - Aaron D Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.
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