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Maalouf CA, Alberti A, Soutourina J. Mediator complex in transcription regulation and DNA repair: Relevance for human diseases. DNA Repair (Amst) 2024; 141:103714. [PMID: 38943827 DOI: 10.1016/j.dnarep.2024.103714] [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: 03/21/2024] [Revised: 06/15/2024] [Accepted: 06/18/2024] [Indexed: 07/01/2024]
Abstract
The Mediator complex is an essential coregulator of RNA polymerase II transcription. More recent developments suggest Mediator functions as a link between transcription regulation, genome organisation and DNA repair mechanisms including nucleotide excision repair, base excision repair, and homologous recombination. Dysfunctions of these processes are frequently associated with human pathologies, and growing evidence shows Mediator involvement in cancers, neurological, metabolic and infectious diseases. The detailed deciphering of molecular mechanisms of Mediator functions, using interdisciplinary approaches in different biological models and considering all functions of this complex, will contribute to our understanding of relevant human diseases.
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Affiliation(s)
- Christelle A Maalouf
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Adriana Alberti
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Julie Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France.
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2
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DeHaro-Arbona FJ, Roussos C, Baloul S, Townson J, Gómez Lamarca MJ, Bray S. Dynamic modes of Notch transcription hubs conferring memory and stochastic activation revealed by live imaging the co-activator Mastermind. eLife 2024; 12:RP92083. [PMID: 38727722 PMCID: PMC11087053 DOI: 10.7554/elife.92083] [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] [Indexed: 05/12/2024] Open
Abstract
Developmental programming involves the accurate conversion of signalling levels and dynamics to transcriptional outputs. The transcriptional relay in the Notch pathway relies on nuclear complexes containing the co-activator Mastermind (Mam). By tracking these complexes in real time, we reveal that they promote the formation of a dynamic transcription hub in Notch ON nuclei which concentrates key factors including the Mediator CDK module. The composition of the hub is labile and persists after Notch withdrawal conferring a memory that enables rapid reformation. Surprisingly, only a third of Notch ON hubs progress to a state with nascent transcription, which correlates with polymerase II and core Mediator recruitment. This probability is increased by a second signal. The discovery that target-gene transcription is probabilistic has far-reaching implications because it implies that stochastic differences in Notch pathway output can arise downstream of receptor activation.
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Affiliation(s)
- F Javier DeHaro-Arbona
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
| | - Charalambos Roussos
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
| | - Sarah Baloul
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
| | - Jonathan Townson
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
| | - María J Gómez Lamarca
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocıo/CSIC/Universidad de Sevilla, Departamento de Biologıa CelularSevilleSpain
| | - Sarah Bray
- Department of Physiology Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
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Yang S, Niou ZX, Enriquez A, LaMar J, Huang JY, Ling K, Jafar-Nejad P, Gilley J, Coleman MP, Tennessen JM, Rangaraju V, Lu HC. NMNAT2 supports vesicular glycolysis via NAD homeostasis to fuel fast axonal transport. Mol Neurodegener 2024; 19:13. [PMID: 38282024 PMCID: PMC10823734 DOI: 10.1186/s13024-023-00690-9] [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: 05/09/2023] [Accepted: 11/28/2023] [Indexed: 01/30/2024] Open
Abstract
BACKGROUND Bioenergetic maladaptations and axonopathy are often found in the early stages of neurodegeneration. Nicotinamide adenine dinucleotide (NAD), an essential cofactor for energy metabolism, is mainly synthesized by Nicotinamide mononucleotide adenylyl transferase 2 (NMNAT2) in CNS neurons. NMNAT2 mRNA levels are reduced in the brains of Alzheimer's, Parkinson's, and Huntington's disease. Here we addressed whether NMNAT2 is required for axonal health of cortical glutamatergic neurons, whose long-projecting axons are often vulnerable in neurodegenerative conditions. We also tested if NMNAT2 maintains axonal health by ensuring axonal ATP levels for axonal transport, critical for axonal function. METHODS We generated mouse and cultured neuron models to determine the impact of NMNAT2 loss from cortical glutamatergic neurons on axonal transport, energetic metabolism, and morphological integrity. In addition, we determined if exogenous NAD supplementation or inhibiting a NAD hydrolase, sterile alpha and TIR motif-containing protein 1 (SARM1), prevented axonal deficits caused by NMNAT2 loss. This study used a combination of techniques, including genetics, molecular biology, immunohistochemistry, biochemistry, fluorescent time-lapse imaging, live imaging with optical sensors, and anti-sense oligos. RESULTS We provide in vivo evidence that NMNAT2 in glutamatergic neurons is required for axonal survival. Using in vivo and in vitro studies, we demonstrate that NMNAT2 maintains the NAD-redox potential to provide "on-board" ATP via glycolysis to vesicular cargos in distal axons. Exogenous NAD+ supplementation to NMNAT2 KO neurons restores glycolysis and resumes fast axonal transport. Finally, we demonstrate both in vitro and in vivo that reducing the activity of SARM1, an NAD degradation enzyme, can reduce axonal transport deficits and suppress axon degeneration in NMNAT2 KO neurons. CONCLUSION NMNAT2 ensures axonal health by maintaining NAD redox potential in distal axons to ensure efficient vesicular glycolysis required for fast axonal transport.
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Affiliation(s)
- Sen Yang
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
| | - Zhen-Xian Niou
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Andrea Enriquez
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Jacob LaMar
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
- Present address: Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, 33458, USA
| | - Jui-Yen Huang
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Karen Ling
- Neuroscience Drug Discovery, Ionis Pharmaceuticals, Inc., 2855, Gazelle Court, Carlsbad, CA, 92010, USA
| | - Paymaan Jafar-Nejad
- Neuroscience Drug Discovery, Ionis Pharmaceuticals, Inc., 2855, Gazelle Court, Carlsbad, CA, 92010, USA
| | - Jonathan Gilley
- Department of Clinical Neuroscience, Cambridge University, Cambridge, UK
| | - Michael P Coleman
- Department of Clinical Neuroscience, Cambridge University, Cambridge, UK
| | - Jason M Tennessen
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - Vidhya Rangaraju
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
| | - Hui-Chen Lu
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA.
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Snyder K, Gorse K, Kochanek PM, Jackson TC. Neuronal RBM5 modulates cell signaling responses to traumatic and hypoxic-ischemic injury in a sex-dependent manner. Cell Death Discov 2023; 9:379. [PMID: 37848418 PMCID: PMC10582027 DOI: 10.1038/s41420-023-01677-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/22/2023] [Accepted: 10/03/2023] [Indexed: 10/19/2023] Open
Abstract
It is not clear if inhibiting the pro-death gene RNA binding motif 5 (RBM5) is neuroprotective in isolated primary neurons or if it regulates cell survival in a sex-dependent manner. Here we established sex-dichotomized primary cortical neuron cultures from transgenic mice harboring a floxed RBM5 gene-trap. Lentivirus-mediated expression of CRE was used to silence RBM5 expression. Male and female neurons were maintained in next-generation Neurobasal-Plus media and subjected to a mechanical stretch-injury (to model traumatic brain injury) or oxygen-glucose deprivation/OGD (to model ischemia). RBM5 KO did not affect 24 h post-injury survival as determined by lactate dehydrogenase (LDH) release, in either paradigm. In contrast, female KO neurons had increased spectrin breakdown products post-insult (in both models). Furthermore, in OGD, RBM5 KO in male neurons exacerbated injury-induced downregulation of pro-survival AKT activation (pAKT473) but conversely led to pAKT473 sparing in female neurons. Moreover, global proteomics identified 19 differentially expressed (DE) proteins in OGD-injured male neurons, and 102 DE proteins in injured female neurons. Two novel RBM5-regulated proteins (PIGQ and EST1C) were identified in injured male KO neurons, and 8 novel proteins identified in injured female KO neurons (S35A5, DHTK1, STX3, IF3M, RN167, K1C14, DYHS, and MED13). In summary, RBM5 inhibition does not modify neuronal survival in primary mouse neurons in 2 clinically relevant models of excitotoxic insult, but RBM5 does regulate intracellular responses to injury in a sex-dependent manner.
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Affiliation(s)
- Kara Snyder
- University of South Florida, Morsani College of Medicine, USF Health Heart Institute, MDD 0630, 560 Channelside Dr, Tampa, FL, 33602, USA
- University of South Florida, Morsani College of Medicine, Department of Molecular Pharmacology & Physiology, 12901 Bruce B Downs Blvd, Tampa, FL, 33612, USA
| | - Kiersten Gorse
- University of South Florida, Morsani College of Medicine, USF Health Heart Institute, MDD 0630, 560 Channelside Dr, Tampa, FL, 33602, USA
- University of South Florida, Morsani College of Medicine, Department of Molecular Pharmacology & Physiology, 12901 Bruce B Downs Blvd, Tampa, FL, 33612, USA
| | - Patrick M Kochanek
- Safar Center for Resuscitation Research, UPMC Children's Hospital of Pittsburgh, Rangos Research Center - 6th floor, Pittsburgh, PA, 15224, USA
| | - Travis C Jackson
- University of South Florida, Morsani College of Medicine, USF Health Heart Institute, MDD 0630, 560 Channelside Dr, Tampa, FL, 33602, USA.
- University of South Florida, Morsani College of Medicine, Department of Molecular Pharmacology & Physiology, 12901 Bruce B Downs Blvd, Tampa, FL, 33612, USA.
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Barros LF, Ruminot I, Sandoval PY, San Martín A. Enlightening brain energy metabolism. Neurobiol Dis 2023:106211. [PMID: 37352985 DOI: 10.1016/j.nbd.2023.106211] [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: 03/06/2023] [Revised: 05/06/2023] [Accepted: 06/20/2023] [Indexed: 06/25/2023] Open
Abstract
Brain tissue metabolism is distributed across several cell types and subcellular compartments, which activate at different times and with different temporal patterns. The introduction of genetically-encoded fluorescent indicators that are imaged using time-lapse microscopy has opened the possibility of studying brain metabolism at cellular and sub-cellular levels. There are indicators for sugars, monocarboxylates, Krebs cycle intermediates, amino acids, cofactors, and energy nucleotides, which inform about relative levels, concentrations and fluxes. This review offers a brief survey of the metabolic indicators that have been validated in brain cells, with some illustrative examples from the literature. Whereas only a small fraction of the metabolome is currently accessible to fluorescent probes, there are grounds to be optimistic about coming developments and the application of these tools to the study of brain disease.
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Affiliation(s)
- L F Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Facultad de Medicina y Ciencia, Universidad San Sebastián, Valdivia, Chile.
| | - I Ruminot
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Facultad de Ciencias para el Cuidado de La Salud, Universidad San Sebastián, Valdivia, Chile
| | - P Y Sandoval
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Facultad de Ciencias para el Cuidado de La Salud, Universidad San Sebastián, Valdivia, Chile
| | - A San Martín
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Facultad de Ciencias para el Cuidado de La Salud, Universidad San Sebastián, Valdivia, Chile
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Yang S, Niou ZX, Enriquez A, LaMar J, Huang JY, Ling K, Jafar-Nejad P, Gilley J, Coleman MP, Tennessen JM, Rangaraju V, Lu HC. NMNAT2 supports vesicular glycolysis via NAD homeostasis to fuel fast axonal transport. RESEARCH SQUARE 2023:rs.3.rs-2859584. [PMID: 37292715 PMCID: PMC10246254 DOI: 10.21203/rs.3.rs-2859584/v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Background Bioenergetic maladaptations and axonopathy are often found in the early stages of neurodegeneration. Nicotinamide adenine dinucleotide (NAD), an essential cofactor for energy metabolism, is mainly synthesized by Nicotinamide mononucleotide adenylyl transferase 2 (NMNAT2) in CNS neurons. NMNAT2 mRNA levels are reduced in the brains of Alzheimer's, Parkinson's, and Huntington's disease. Here we addressed whether NMNAT2 is required for axonal health of cortical glutamatergic neurons, whose long-projecting axons are often vulnerable in neurodegenerative conditions. We also tested if NMNAT2 maintains axonal health by ensuring axonal ATP levels for axonal transport, critical for axonal function. Methods We generated mouse and cultured neuron models to determine the impact of NMNAT2 loss from cortical glutamatergic neurons on axonal transport, energetic metabolism, and morphological integrity. In addition, we determined if exogenous NAD supplementation or inhibiting a NAD hydrolase, sterile alpha and TIR motif-containing protein 1 (SARM1), prevented axonal deficits caused by NMNAT2 loss. This study used a combination of genetics, molecular biology, immunohistochemistry, biochemistry, fluorescent time-lapse imaging, live imaging with optical sensors, and anti-sense oligos. Results We provide in vivo evidence that NMNAT2 in glutamatergic neurons is required for axonal survival. Using in vivo and in vitro studies, we demonstrate that NMNAT2 maintains the NAD-redox potential to provide "on-board" ATP via glycolysis to vesicular cargos in distal axons. Exogenous NAD+ supplementation to NMNAT2 KO neurons restores glycolysis and resumes fast axonal transport. Finally, we demonstrate both in vitro and in vivo that reducing the activity of SARM1, an NAD degradation enzyme, can reduce axonal transport deficits and suppress axon degeneration in NMNAT2 KO neurons. Conclusion NMNAT2 ensures axonal health by maintaining NAD redox potential in distal axons to ensure efficient vesicular glycolysis required for fast axonal transport.
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Lee RMQ, Koh TW. Genetic modifiers of synucleinopathies-lessons from experimental models. OXFORD OPEN NEUROSCIENCE 2023; 2:kvad001. [PMID: 38596238 PMCID: PMC10913850 DOI: 10.1093/oons/kvad001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/04/2023] [Accepted: 03/07/2023] [Indexed: 04/11/2024]
Abstract
α-Synuclein is a pleiotropic protein underlying a group of progressive neurodegenerative diseases, including Parkinson's disease and dementia with Lewy bodies. Together, these are known as synucleinopathies. Like all neurological diseases, understanding of disease mechanisms is hampered by the lack of access to biopsy tissues, precluding a real-time view of disease progression in the human body. This has driven researchers to devise various experimental models ranging from yeast to flies to human brain organoids, aiming to recapitulate aspects of synucleinopathies. Studies of these models have uncovered numerous genetic modifiers of α-synuclein, most of which are evolutionarily conserved. This review discusses what we have learned about disease mechanisms from these modifiers, and ways in which the study of modifiers have supported ongoing efforts to engineer disease-modifying interventions for synucleinopathies.
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Affiliation(s)
- Rachel Min Qi Lee
- Temasek Life Sciences Laboratory, 1 Research Link, Singapore, 117604, Singapore
| | - Tong-Wey Koh
- Temasek Life Sciences Laboratory, 1 Research Link, Singapore, 117604, Singapore
- Department of Biological Sciences, National University of Singapore, Block S3 #05-01, 16 Science Drive 4, Singapore, 117558, Singapore
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Pan X, Dutta D, Lu S, Bellen HJ. Sphingolipids in neurodegenerative diseases. Front Neurosci 2023; 17:1137893. [PMID: 36875645 PMCID: PMC9978793 DOI: 10.3389/fnins.2023.1137893] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 01/27/2023] [Indexed: 02/18/2023] Open
Abstract
Neurodegenerative Diseases (NDDs) are a group of disorders that cause progressive deficits of neuronal function. Recent evidence argues that sphingolipid metabolism is affected in a surprisingly broad set of NDDs. These include some lysosomal storage diseases (LSDs), hereditary sensory and autonomous neuropathy (HSAN), hereditary spastic paraplegia (HSP), infantile neuroaxonal dystrophy (INAD), Friedreich's ataxia (FRDA), as well as some forms of amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD). Many of these diseases have been modeled in Drosophila melanogaster and are associated with elevated levels of ceramides. Similar changes have also been reported in vertebrate cells and mouse models. Here, we summarize studies using fly models and/or patient samples which demonstrate the nature of the defects in sphingolipid metabolism, the organelles that are implicated, the cell types that are initially affected, and potential therapeutics for these diseases.
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Affiliation(s)
- Xueyang Pan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, United States
| | - Debdeep Dutta
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, United States
| | - Shenzhao Lu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, United States
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
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