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Yuan Y, Yu L, Zhuang X, Wen D, He J, Hong J, Xie J, Ling S, Du X, Chen W, Wang X. Drosophila models used to simulate human ATP1A1 gene mutations that cause Charcot-Marie-Tooth type 2 disease and refractory seizures. Neural Regen Res 2025; 20:265-276. [PMID: 38767491 PMCID: PMC11246156 DOI: 10.4103/1673-5374.391302] [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: 04/25/2023] [Revised: 09/21/2023] [Accepted: 11/06/2023] [Indexed: 05/22/2024] Open
Abstract
JOURNAL/nrgr/04.03/01300535-202501000-00034/figure1/v/2024-05-14T021156Z/r/image-tiff Certain amino acids changes in the human Na+/K+-ATPase pump, ATPase Na+/K+ transporting subunit alpha 1 (ATP1A1), cause Charcot-Marie-Tooth disease type 2 (CMT2) disease and refractory seizures. To develop in vivo models to study the role of Na+/K+-ATPase in these diseases, we modified the Drosophila gene homolog, Atpα, to mimic the human ATP1A1 gene mutations that cause CMT2. Mutations located within the helical linker region of human ATP1A1 (I592T, A597T, P600T, and D601F) were simultaneously introduced into endogenous DrosophilaAtpα by CRISPR/Cas9-mediated genome editing, generating the AtpαTTTF model. In addition, the same strategy was used to generate the corresponding single point mutations in flies (AtpαI571T, AtpαA576T, AtpαP579T, and AtpαD580F). Moreover, a deletion mutation (Atpαmut) that causes premature termination of translation was generated as a positive control. Of these alleles, we found two that could be maintained as homozygotes (AtpαI571T and AtpαP579T). Three alleles (AtpαA576T, AtpαP579 and AtpαD580F) can form heterozygotes with the Atpαmut allele. We found that the Atpα allele carrying these CMT2-associated mutations showed differential phenotypes in Drosophila. Flies heterozygous for AtpαTTTF mutations have motor performance defects, a reduced lifespan, seizures, and an abnormal neuronal morphology. These Drosophila models will provide a new platform for studying the function and regulation of the sodium-potassium pump.
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Affiliation(s)
- Yao Yuan
- Institute of Life Sciences, College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian Province, China
| | - Lingqi Yu
- Institute of Life Sciences, College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian Province, China
| | - Xudong Zhuang
- NHC Key Laboratory of Technical Evaluation of Fertility Regulation for Non-human Primate (Fujian Maternity and Child Health Hospital), Fuzhou, Fujian Province, China
- Medical Research Center, Fujian Maternity and Child Health Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Dongjing Wen
- Institute of Life Sciences, College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian Province, China
| | - Jin He
- Department of Neurology and Institute of Neurology of The First Affiliated Hospital, Institute of Neuroscience, and Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Jingmei Hong
- Department of Neurology and Institute of Neurology of The First Affiliated Hospital, Institute of Neuroscience, and Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Jiayu Xie
- Institute of Life Sciences, College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian Province, China
| | - Shengan Ling
- Institute of Life Sciences, College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian Province, China
| | - Xiaoyue Du
- Institute of Life Sciences, College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian Province, China
| | - Wenfeng Chen
- Institute of Life Sciences, College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian Province, China
| | - Xinrui Wang
- NHC Key Laboratory of Technical Evaluation of Fertility Regulation for Non-human Primate (Fujian Maternity and Child Health Hospital), Fuzhou, Fujian Province, China
- Medical Research Center, Fujian Maternity and Child Health Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, Fujian Province, China
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Lu W, Lee BS, Deng HXY, Lakonishok M, Martin-Blanco E, Gelfand VI. "Mitotic" kinesin-5 is a dynamic brake for axonal growth. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.12.612721. [PMID: 39314406 PMCID: PMC11419024 DOI: 10.1101/2024.09.12.612721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
During neuronal development, neurons undergo significant microtubule reorganization to shape axons and dendrites, establishing the framework for efficient wiring of the nervous system. Previous studies from our laboratory demonstrated the key role of kinesin-1 in driving microtubule-microtubule sliding, which provides the mechanical forces necessary for early axon outgrowth and regeneration in Drosophila melanogaster. In this study, we reveal the critical role of kinesin-5, a mitotic motor, in modulating the development of postmitotic neurons. Kinesin-5, a conserved homotetrameric motor, typically functions in mitosis by sliding antiparallel microtubules apart in the spindle. Here, we demonstrate that the Drosophila kinesin-5 homolog, Klp61F, is expressed in larval brain neurons, with high levels in ventral nerve cord (VNC) neurons. Knockdown of Klp61F using a pan-neuronal driver leads to severe locomotion defects and complete lethality in adult flies, mainly due to the absence of kinesin-5 in VNC motor neurons during early larval development. Klp61F depletion results in significant axon growth defects, both in cultured and in vivo neurons. By imaging individual microtubules, we observe a significant increase in microtubule motility, and excessive penetration of microtubules into the axon growth cone in Klp61F-depleted neurons. Adult lethality and axon growth defects are fully rescued by a chimeric human-Drosophila kinesin-5 motor, which accumulates at the axon tips, suggesting a conserved role of kinesin-5 in neuronal development. Altogether, our findings show that at the growth cone, kinesin-5 acts as a brake on kinesin-1-driven microtubule sliding, preventing premature microtubule entry into the growth cone. This regulatory role of kinesin-5 is essential for precise axon pathfinding during nervous system development.
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Affiliation(s)
- Wen Lu
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Brad S Lee
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Helen Xue Ying Deng
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Margot Lakonishok
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Enrique Martin-Blanco
- Instituto de Biología Molecular de Barcelona, CSIC, Parc Cientific de Barcelona, Baldiri Reixac 10-12, 08028 Barcelona, Spain
| | - Vladimir I Gelfand
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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Glineburg MR, Yildirim E, Gomez N, Rodriguez G, Pak J, Li X, Altheim C, Waksmacki J, McInerney GM, Barmada SJ, Todd PK. Stress granule formation helps to mitigate neurodegeneration. Nucleic Acids Res 2024; 52:9745-9759. [PMID: 39106168 PMCID: PMC11381325 DOI: 10.1093/nar/gkae655] [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: 11/10/2023] [Revised: 05/28/2024] [Accepted: 07/17/2024] [Indexed: 08/09/2024] Open
Abstract
Cellular stress pathways that inhibit translation initiation lead to transient formation of cytoplasmic RNA/protein complexes known as stress granules. Many of the proteins found within stress granules and the dynamics of stress granule formation and dissolution are implicated in neurodegenerative disease. Whether stress granule formation is protective or harmful in neurodegenerative conditions is not known. To address this, we took advantage of the alphavirus protein nsP3, which selectively binds dimers of the central stress granule nucleator protein G3BP and markedly reduces stress granule formation without directly impacting the protein translational inhibitory pathways that trigger stress granule formation. In Drosophila and rodent neurons, reducing stress granule formation with nsP3 had modest impacts on lifespan even in the setting of serial stress pathway induction. In contrast, reducing stress granule formation in models of ataxia, amyotrophic lateral sclerosis and frontotemporal dementia largely exacerbated disease phenotypes. These data support a model whereby stress granules mitigate, rather than promote, neurodegenerative cascades.
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Affiliation(s)
- M Rebecca Glineburg
- Biological Sciences, Schmid College of Science and Technology, Chapman University, 1 University Drive, Orange, CA 92866, USA
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Evrim Yildirim
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Nicolas Gomez
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
- Cell and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Genesis Rodriguez
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Jaclyn Pak
- Biological Sciences, Schmid College of Science and Technology, Chapman University, 1 University Drive, Orange, CA 92866, USA
| | - Xingli Li
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Christopher Altheim
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Jacob Waksmacki
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Gerald M McInerney
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm 17165, Sweden
| | - Sami J Barmada
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, BSRB48109-2200, Ann Arbor, MI 4005, USA
- Veterans Affairs Medical Center, Ann Arbor, MI, USA
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Hana TA, Mousa VG, Lin A, Haj-Hussein RN, Michael AH, Aziz MN, Kamaridinova SU, Basnet S, Ormerod KG. Developmental and physiological impacts of pathogenic human huntingtin protein in the nervous system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.30.610525. [PMID: 39257834 PMCID: PMC11383668 DOI: 10.1101/2024.08.30.610525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2024]
Abstract
Huntington's Disease (HD) is a neurodegenerative disorder, part of the nine identified inherited polyglutamine (polyQ) diseases. Most commonly, HD pathophysiology manifests in middle-aged adults with symptoms including progressive loss of motor control, cognitive decline, and psychiatric disturbances. Associated with the pathophysiology of HD is the formation of insoluble fragments of the huntingtin protein (htt) that tend to aggregate in the nucleus and cytoplasm of neurons. To track both the intracellular progression of the aggregation phenotype as well as the physiological deficits associated with mutant htt, two constructs of human HTT were expressed with varying polyQ lengths, non-pathogenic-htt (Q15, NP-htt) and pathogenic-htt (Q138, P-htt), with an N-terminal RFP tag for in vivo visualization. P-htt aggregates accumulate in the ventral nerve cord cell bodies as early as 24 hours post hatching and significant aggregates form in the segmental nerve branches at 48 hours post hatching. Organelle trafficking up-and downstream of aggregates formed in motor neurons showed severe deficits in trafficking dynamics. To explore putative downstream deficits of htt aggregation, ultrastructural changes of presynaptic motor neurons and muscles were assessed, but no significant effects were observed. However, the force and kinetics of muscle contractions were severely affected in P-htt animals, reminiscent of human chorea. Reduced muscle force production translated to altered locomotory behavior. A novel HD aggregation model was established to track htt aggregation throughout adulthood in the wing, showing similar aggregation patterns with larvae. Expressing P-htt in the adult nervous system resulted in significantly reduced lifespan, which could be partially rescued by feeding flies the mTOR inhibitor rapamycin. These findings advance our understanding of htt aggregate progression as well the downstream physiological impacts on the nervous system and peripheral tissues.
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Chitre K, Kairamkonda S, Dwivedi MK, Yadav S, Kumar V, Sikdar SK, Nongthomba U. Beadex, the Drosophila LIM only protein, is required for the growth of the larval neuromuscular junction. J Neurophysiol 2024; 132:418-432. [PMID: 38838299 DOI: 10.1152/jn.00064.2024] [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: 02/12/2024] [Revised: 05/31/2024] [Accepted: 06/05/2024] [Indexed: 06/07/2024] Open
Abstract
The appropriate growth of the neurons, accurate organization of their synapses, and successful neurotransmission are indispensable for sensorimotor activities. These processes are highly dynamic and tightly regulated. Extensive genetic, molecular, physiological, and behavioral studies have identified many molecular candidates and investigated their roles in various neuromuscular processes. In this article, we show that Beadex (Bx), the Drosophila LIM only (LMO) protein, is required for motor activities and neuromuscular growth of Drosophila. The larvae bearing Bx7, a null allele of Bx, and the RNAi-mediated neuronal-specific knockdown of Bx show drastically reduced crawling behavior, a diminished synaptic span of the neuromuscular junctions (NMJs) and an increased spontaneous neuronal firing with altered motor patterns in the central pattern generators (CPGs). Microarray studies identified multiple targets of Beadex that are involved in different cellular and molecular pathways, including those associated with the cytoskeleton and mitochondria that could be responsible for the observed neuromuscular defects. With genetic interaction studies, we further show that Highwire (Hiw), a negative regulator of synaptic growth at the NMJs, negatively regulates Bx, as the latter's deficiency was able to rescue the phenotype of the Hiw null mutant, HiwDN. Thus, our data indicate that Beadex functions downstream of Hiw to regulate the larval synaptic growth and physiology.NEW & NOTEWORTHY A novel role for Beadex (Bx) regulates the larval neuromuscular junction (NMJ) structure and function in a tissue-specific manner. Bx is expressed in a subset of Toll-6-expressing neurons and is involved in regulating synaptic span and physiology, possibly through its negative interaction with Highwire (Hiw). The findings of this study provide insights into the molecular mechanisms underlying NMJ development and function and warrant further investigation to understand the role of Bx in these processes fully.
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Affiliation(s)
- Kripa Chitre
- Department of Development Biology and Genetics (DBG), Indian Institute of Science (IISc), Bangalore, India
| | - Subhash Kairamkonda
- Department of Development Biology and Genetics (DBG), Indian Institute of Science (IISc), Bangalore, India
| | - Manish Kumar Dwivedi
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, India
| | - Saumitra Yadav
- Molecular Biophysics Unit (MBU), Indian Institute of Science (IISc), Bangalore, India
| | - Vimlesh Kumar
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, India
| | - Sujit K Sikdar
- Molecular Biophysics Unit (MBU), Indian Institute of Science (IISc), Bangalore, India
| | - Upendra Nongthomba
- Department of Development Biology and Genetics (DBG), Indian Institute of Science (IISc), Bangalore, India
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6
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Odierna GL, Kerwin SK, Shin GJE, Millard SS. Drosophila larval motor patterning relies on regulated alternative splicing of Dscam2. Front Mol Neurosci 2024; 17:1415207. [PMID: 39092203 PMCID: PMC11292952 DOI: 10.3389/fnmol.2024.1415207] [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: 04/10/2024] [Accepted: 05/31/2024] [Indexed: 08/04/2024] Open
Abstract
Recent studies capitalizing on the newly complete nanometer-resolution Drosophila larval connectome have made significant advances in identifying the structural basis of motor patterning. However, the molecular mechanisms utilized by neurons to wire these circuits remain poorly understood. In this study we explore how cell-specific expression of two Dscam2 isoforms, which mediate isoform-specific homophilic binding, contributes to motor patterning and output of Drosophila larvae. Ablating Dscam2 isoform diversity resulted in impaired locomotion. Electrophysiological assessment at the neuromuscular junction during fictive locomotion indicated that this behavioral defect was largely caused by weaker bouts of motor neuron activity. Morphological analyses of single motor neurons using MultiColour FlpOut revealed severe errors in dendrite arborization and assessment of cholinergic and GABAergic projections to the motor domain revealed altered morphology of interneuron processes. Loss of Dscam2 did not affect locomotor output, motor neuron activation or dendrite targeting. Our findings thus suggest that locomotor circuit phenotypes arise specifically from inappropriate Dscam2 interactions between premotor interneurons and motor neurons when they express the same isoform. Indeed, we report here that first-order premotor interneurons express Dscam2A. Since motor neurons express Dscam2B, our results provide evidence that Dscam2 isoform expression alternates between synaptic partners in the nerve cord. Our study demonstrates the importance of cell-specific alternative splicing in establishing the circuitry that underlies neuromotor patterning without inducing unwanted intercellular interactions.
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Affiliation(s)
- G. Lorenzo Odierna
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Sarah K. Kerwin
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Grace Ji-eun Shin
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, United States
- The Neuroscience Research Institute, The Ohio State University, Columbus, OH, United States
- The Ohio State University Comprehensive Cancer Center, Columbus, OH, United States
| | - S. Sean Millard
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
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Das D, Ghosh G, Dutta A, Sherpa RD, Ghosh P, Hui SP, Ghosh S. Fruit ripening retardant Daminozide induces cognitive impairment, cell specific neurotoxicity, and genotoxicity in Drosophila melanogaster. Neurotoxicology 2024; 103:123-133. [PMID: 38851594 DOI: 10.1016/j.neuro.2024.06.002] [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: 03/26/2024] [Revised: 05/30/2024] [Accepted: 06/04/2024] [Indexed: 06/10/2024]
Abstract
BACKGROUND We explored neurotoxic and genotoxic effects of Daminozide, a fruit ripening retardant, on the brain of Drosophila melanogaster, based on our previous finding of DNA fragmentation in larval brain cell in the flies experimentally exposed to this chemicals. METHODS Adult flies were subjected to two distinct concentrations of daminozide (200 mg/L and 400 mg/L) mixed in culture medium, followed by an examination of specific behaviors such as courtship conditioning and aversive phototaxis, which serve as indicators of cognitive functions. We investigated brain histology and histochemistry to assess the overall toxicity of daminozide, focusing on neuron type-specific effects. Additionally, we conducted studies on gene expression specific to neuronal function. Statistical comparisons were then made between the exposed and control flies across all tested attributes. RESULTS The outcome of behavioral assays suggested deleterious effects of Daminozide on learning, short term and long term memory function. Histological examination of brain sections revealed cellular degeneration, within Kenyon cell neuropiles in Daminozide-exposed flies. Neurone specific Immuno-histochemistry study revealed significant reduction of dopaminergic and glutaminergic neurones with discernible reduction in cellular counts, alteration in cell and nuclear morphology among daminozide exposed flies. Gene expression analyses demonstrated upregulation of rutabaga (rut), hb9 and down regulation of PKa- C1, CrebB, Ace and nAchRbeta-1 in exposed flies which suggest dysregulation of gene functions involved in motor neuron activity, learning, and memory. CONCLUSION Taken together, our findings suggests that Daminozide induces multifaceted harmful impacts on the neural terrain of Drosophila melanogaster, posing a threat to its cognitive abilities.
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Affiliation(s)
- Debasmita Das
- Department of Zoology, University of Calcutta, Kolkata, India
| | - Gaurab Ghosh
- Department of Biological Sciences, Indian Institute of Science Education & Research (IISER)- Kolkata Mohanpur Campus, Mohanpur, Nadia, West Bengal, India
| | - Arthita Dutta
- Department of Zoology, University of Calcutta, Kolkata, India
| | - Rinchen D Sherpa
- S. N. Pradhan Centre for Neurosciences, University of Calcutta, Kolkata, India
| | - Papiya Ghosh
- Department of Zoology, Bijoykrishna Girls' College. Howrah. India
| | - Subhra Prakash Hui
- S. N. Pradhan Centre for Neurosciences, University of Calcutta, Kolkata, India
| | - Sujay Ghosh
- Department of Zoology, University of Calcutta, Kolkata, India.
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Hatfield T, Johnson S. Knockdown of the GABARAP ortholog Atg8a elicits deficits in learning and promotes obsessive behaviors in Drosophila melanogaster. MICROPUBLICATION BIOLOGY 2024; 2024. [PMID: 38882929 PMCID: PMC11177113 DOI: 10.17912/micropub.biology.001116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 05/13/2024] [Accepted: 05/28/2024] [Indexed: 06/18/2024]
Abstract
In humans, trafficking of the GABA(A) receptor by GABARAP can lead to obsessive behaviors and learning deficits often in seen in neurological disorders such as Tourette's Syndrome. We find that in Drosophila melanogaster , Atg8a , the ortholog of the human GABARAP gene, is necessary in the nervous system for learning and suppression of excessive grooming. These results suggest that knocking down Atg8a in neurons of Drosophila produces a phenotype similar to that seen in human patients, potentially allowing for use of an Atg8a knockdown background as a suitable invertebrate model for related neurological conditions.
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Affiliation(s)
- Theodore Hatfield
- Department of Biology, Simmons University, Boston, Massachusetts, United States
| | - Seth Johnson
- Department of Biology, Simmons University, Boston, Massachusetts, United States
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Gabrawy MM, Westbrook R, King A, Khosravian N, Ochaney N, DeCarvalho T, Wang Q, Yu Y, Huang Q, Said A, Abadir M, Zhang C, Khare P, Fairman JE, Le A, Milne GL, Vonhoff FJ, Walston JD, Abadir PM. Dual treatment with kynurenine pathway inhibitors and NAD + precursors synergistically extends life span in Drosophila. Aging Cell 2024; 23:e14102. [PMID: 38481042 PMCID: PMC11019140 DOI: 10.1111/acel.14102] [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: 11/17/2023] [Revised: 01/19/2024] [Accepted: 01/24/2024] [Indexed: 04/17/2024] Open
Abstract
Tryptophan catabolism is highly conserved and generates important bioactive metabolites, including kynurenines, and in some animals, NAD+. Aging and inflammation are associated with increased levels of kynurenine pathway (KP) metabolites and depleted NAD+, factors which are implicated as contributors to frailty and morbidity. Contrastingly, KP suppression and NAD+ supplementation are associated with increased life span in some animals. Here, we used DGRP_229 Drosophila to elucidate the effects of KP elevation, KP suppression, and NAD+ supplementation on physical performance and survivorship. Flies were chronically fed kynurenines, KP inhibitors, NAD+ precursors, or a combination of KP inhibitors with NAD+ precursors. Flies with elevated kynurenines had reduced climbing speed, endurance, and life span. Treatment with a combination of KP inhibitors and NAD+ precursors preserved physical function and synergistically increased maximum life span. We conclude that KP flux can regulate health span and life span in Drosophila and that targeting KP and NAD+ metabolism can synergistically increase life span.
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Affiliation(s)
- Mariann M. Gabrawy
- School of Medicine, Division of Geriatric Medicine and Gerontology, Biology of Healthy Aging ProgramJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Reyhan Westbrook
- School of Medicine, Division of Geriatric Medicine and Gerontology, Biology of Healthy Aging ProgramJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Austin King
- School of Medicine, Division of Geriatric Medicine and Gerontology, Biology of Healthy Aging ProgramJohns Hopkins UniversityBaltimoreMarylandUSA
- Department of Biological SciencesUniversity of Maryland, Baltimore CountyBaltimoreMarylandUSA
| | - Nick Khosravian
- School of Medicine, Division of Geriatric Medicine and Gerontology, Biology of Healthy Aging ProgramJohns Hopkins UniversityBaltimoreMarylandUSA
- Department of Biological SciencesUniversity of Maryland, Baltimore CountyBaltimoreMarylandUSA
| | - Neeraj Ochaney
- School of Medicine, Division of Geriatric Medicine and Gerontology, Biology of Healthy Aging ProgramJohns Hopkins UniversityBaltimoreMarylandUSA
- Department of Biological SciencesUniversity of Maryland, Baltimore CountyBaltimoreMarylandUSA
| | - Tagide DeCarvalho
- Department of Biological SciencesUniversity of Maryland, Baltimore CountyBaltimoreMarylandUSA
| | - Qinchuan Wang
- School of Medicine, Division of Geriatric Medicine and Gerontology, Biology of Healthy Aging ProgramJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Yuqiong Yu
- School of Medicine, Division of Geriatric Medicine and Gerontology, Biology of Healthy Aging ProgramJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Qiao Huang
- School of Medicine, Division of Geriatric Medicine and Gerontology, Biology of Healthy Aging ProgramJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Adam Said
- School of Medicine, Division of Geriatric Medicine and Gerontology, Biology of Healthy Aging ProgramJohns Hopkins UniversityBaltimoreMarylandUSA
- Emory UniversityAtlantaGeorgiaUSA
| | - Michael Abadir
- School of Medicine, Division of Geriatric Medicine and Gerontology, Biology of Healthy Aging ProgramJohns Hopkins UniversityBaltimoreMarylandUSA
- University of Maryland, College ParkCollege ParkMarylandUSA
| | | | | | - Jennifer E. Fairman
- Department of Arts as Applied to MedicineJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Anne Le
- Gigantest Inc.BaltimoreMarylandUSA
| | - Ginger L. Milne
- Vanderbilt UniversityVanderbilt Brain Institute, Neurochemistry CoreNashvilleTennesseeUSA
| | - Fernando J. Vonhoff
- Department of Biological SciencesUniversity of Maryland, Baltimore CountyBaltimoreMarylandUSA
| | - Jeremy D. Walston
- School of Medicine, Division of Geriatric Medicine and Gerontology, Biology of Healthy Aging ProgramJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Peter M. Abadir
- School of Medicine, Division of Geriatric Medicine and Gerontology, Biology of Healthy Aging ProgramJohns Hopkins UniversityBaltimoreMarylandUSA
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10
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Son W, Jeong HS, Nam DE, Lee AJ, Nam SH, Lee JE, Choi BO, Chung KW. Peripheral Neuropathy and Decreased Locomotion of a RAB40B Mutation in Human and Model Animals. Exp Neurobiol 2023; 32:410-422. [PMID: 38196136 PMCID: PMC10789172 DOI: 10.5607/en23027] [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: 08/30/2023] [Revised: 12/13/2023] [Accepted: 12/15/2023] [Indexed: 01/11/2024] Open
Abstract
Rab40 proteins are an atypical subgroup of Rab GTPases containing a unique suppressor of the cytokine signaling (SOCS) domain that is recruited to assemble the CRL5 E3 ligase complex for proteolytic regulation in various biological processes. A nonsense mutation deleting the C-terminal SOCS box in the RAB40B gene was identified in a family with axonal peripheral neuropathy (Charcot-Marie-Tooth disease type 2), and pathogenicity of the mutation was assessed in model organisms of zebrafish and Drosophila. Compared to control fish, zebrafish larvae transformed by the human mutant hRAB40B-Y83X showed a defective swimming pattern of stalling with restricted localization and slower motility. We were consistently able to observe reduced labeling of synaptic markers along neuromuscular junctions of the transformed larvae. In addition to the neurodevelopmental phenotypes, compared to normal hRAB40B expression, we further examined ectopic expression of hRAB40B-Y83X in Drosophila to show a progressive decline of locomotion ability. Decreased ability of locomotion by ubiquitous expression of the human mutation was reproduced not with GAL4 drivers for neuron-specific expression but only when a pan-glial GAL4 driver was applied. Using the ectopic expression model of Drosophila, we identified a genetic interaction in which Cul5 down regulation exacerbated the defective motor performance, showing a consistent loss of SOCS box of the pathogenic RAB40B. Taken together, we could assess the possible gain-of-function of the human RAB40B mutation by comparing behavioral phenotypes in animal models; our results suggest that the mutant phenotypes may be associated with CRL5-mediated proteolytic regulation.
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Affiliation(s)
- Wonseok Son
- Department of Biological Sciences and BK21 Team for Field-oriented BioCore Human Resources Development, Kongju National University, Gongju 32588, Korea
| | - Hui Su Jeong
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences & Technology, Sungkyunkwan University, Seoul 06351, Korea
| | - Da Eun Nam
- Department of Biological Sciences and BK21 Team for Field-oriented BioCore Human Resources Development, Kongju National University, Gongju 32588, Korea
| | - Ah Jin Lee
- Department of Biological Sciences and BK21 Team for Field-oriented BioCore Human Resources Development, Kongju National University, Gongju 32588, Korea
| | - Soo Hyun Nam
- Cell and Gene Therapy Institute, Samsung Medical Center, Seoul 06351, Korea
| | - Ji Eun Lee
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences & Technology, Sungkyunkwan University, Seoul 06351, Korea
- Samsung Biomedical Research Institute, Samsung Medical Center, Seoul 06351, Korea
| | - Byung-Ok Choi
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences & Technology, Sungkyunkwan University, Seoul 06351, Korea
- Cell and Gene Therapy Institute, Samsung Medical Center, Seoul 06351, Korea
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea
| | - Ki Wha Chung
- Department of Biological Sciences and BK21 Team for Field-oriented BioCore Human Resources Development, Kongju National University, Gongju 32588, Korea
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11
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Waller TJ, Collins CA. Opposing roles of Fos, Raw, and SARM1 in the regulation of axonal degeneration and synaptic structure. Front Cell Neurosci 2023; 17:1283995. [PMID: 38099151 PMCID: PMC10719852 DOI: 10.3389/fncel.2023.1283995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 10/30/2023] [Indexed: 12/17/2023] Open
Abstract
Introduction The degeneration of injured axons is driven by conserved molecules, including the sterile armadillo TIR domain-containing protein SARM1, the cJun N-terminal kinase JNK, and regulators of these proteins. These molecules are also implicated in the regulation of synapse development though the mechanistic relationship of their functions in degeneration vs. development is poorly understood. Results and discussion Here, we uncover disparate functional relationships between SARM1 and the transmembrane protein Raw in the regulation of Wallerian degeneration and synaptic growth in motoneurons of Drosophila melanogaster. Our genetic data suggest that Raw antagonizes the downstream output MAP kinase signaling mediated by Drosophila SARM1 (dSarm). This relationship is revealed by dramatic synaptic overgrowth phenotypes at the larval neuromuscular junction when motoneurons are depleted for Raw or overexpress dSarm. While Raw antagonizes the downstream output of dSarm to regulate synaptic growth, it shows an opposite functional relationship with dSarm for axonal degeneration. Loss of Raw leads to decreased levels of dSarm in axons and delayed axonal degeneration that is rescued by overexpression of dSarm, supporting a model that Raw promotes the activation of dSarm in axons. However, inhibiting Fos also decreases dSarm levels in axons but has the opposite outcome of enabling Wallerian degeneration. The combined genetic data suggest that Raw, dSarm, and Fos influence each other's functions through multiple points of regulation to control the structure of synaptic terminals and the resilience of axons to degeneration.
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Affiliation(s)
- Thomas J. Waller
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Catherine A. Collins
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, United States
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12
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Bazzi W, Monticelli S, Delaporte C, Riet C, Giangrande A, Cattenoz PB. Gcm counteracts Toll-induced inflammation and impacts hemocyte number through cholinergic signaling. Front Immunol 2023; 14:1293766. [PMID: 38035083 PMCID: PMC10684909 DOI: 10.3389/fimmu.2023.1293766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 10/26/2023] [Indexed: 12/02/2023] Open
Abstract
Hemocytes, the myeloid-like immune cells of Drosophila, fulfill a variety of functions that are not completely understood, ranging from phagocytosis to transduction of inflammatory signals. We here show that downregulating the hemocyte-specific Glial cell deficient/Glial cell missing (Glide/Gcm) transcription factor enhances the inflammatory response to the constitutive activation of the Toll pathway. This correlates with lower levels of glutathione S-transferase, suggesting an implication of Glide/Gcm in reactive oxygen species (ROS) signaling and calling for a widespread anti-inflammatory potential of Glide/Gcm. In addition, our data reveal the expression of acetylcholine receptors in hemocytes and that Toll activation affects their expressions, disclosing a novel aspect of the inflammatory response mediated by neurotransmitters. Finally, we provide evidence for acetylcholine receptor nicotinic acetylcholine receptor alpha 6 (nAchRalpha6) regulating hemocyte proliferation in a cell autonomous fashion and for non-cell autonomous cholinergic signaling regulating the number of hemocytes. Altogether, this study provides new insights on the molecular pathways involved in the inflammatory response.
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Affiliation(s)
- Wael Bazzi
- Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
- CNRS, UMR 7104, Illkirch, France
- Inserm, UMR-S 1258, Illkirch, France
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
| | - Sara Monticelli
- Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
- CNRS, UMR 7104, Illkirch, France
- Inserm, UMR-S 1258, Illkirch, France
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
| | - Claude Delaporte
- Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
- CNRS, UMR 7104, Illkirch, France
- Inserm, UMR-S 1258, Illkirch, France
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
| | - Céline Riet
- Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
- CNRS, UMR 7104, Illkirch, France
- Inserm, UMR-S 1258, Illkirch, France
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
| | - Angela Giangrande
- Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
- CNRS, UMR 7104, Illkirch, France
- Inserm, UMR-S 1258, Illkirch, France
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
| | - Pierre B. Cattenoz
- Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
- CNRS, UMR 7104, Illkirch, France
- Inserm, UMR-S 1258, Illkirch, France
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
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13
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Chen X, Perry S, Wang B, Wang S, Hu J, Loxterkamp E, Dickman D, Han C. Tissue-specific knockout in Drosophila neuromuscular system reveals ESCRT's role in formation of synapse-derived extracellular vesicles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.25.559303. [PMID: 37808853 PMCID: PMC10557614 DOI: 10.1101/2023.09.25.559303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Tissue-specific gene knockout by CRISPR/Cas9 is a powerful approach for characterizing gene functions in animal development. However, this approach has been successfully applied in only a small number of Drosophila tissues. The Drosophila motor nervous system is an excellent model system for studying the biology of neuromuscular junction (NMJ). To expand tissue-specific CRISPR to the Drosophila motor system, here we present a CRISPR-mediated tissue-restricted mutagenesis (CRISPR-TRiM) toolkit for knocking out genes in motoneurons, muscles, and glial cells. We validated the efficacy of this toolkit by knocking out known genes in each tissue, demonstrated its orthogonal use with the Gal4/UAS binary expression system, and showed simultaneous knockout of multiple redundant genes. Using these tools, we discovered an essential role for SNARE pathways in NMJ maintenance. Furthermore, we demonstrate that the canonical ESCRT pathway suppresses NMJ bouton growth by downregulating the retrograde Gbb signaling. Lastly, we found that axon termini of motoneurons rely on ESCRT-mediated intra-axonal membrane trafficking to lease extracellular vesicles at the NMJ.
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Affiliation(s)
- Xinchen Chen
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Sarah Perry
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Bei Wang
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Shuran Wang
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Jiayi Hu
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Elizabeth Loxterkamp
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Chun Han
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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14
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Dunn E, Steinert JR, Stone A, Sahota V, Williams RSB, Snowden S, Augustin H. Medium-Chain Fatty Acids Rescue Motor Function and Neuromuscular Junction Degeneration in a Drosophila Model of Amyotrophic Lateral Sclerosis. Cells 2023; 12:2163. [PMID: 37681895 PMCID: PMC10486503 DOI: 10.3390/cells12172163] [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: 07/26/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 09/09/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disease characterised by progressive degeneration of the motor neurones. An expanded GGGGCC (G4C2) hexanucleotide repeat in C9orf72 is the most common genetic cause of ALS and frontotemporal dementia (FTD); therefore, the resulting disease is known as C9ALS/FTD. Here, we employ a Drosophila melanogaster model of C9ALS/FTD (C9 model) to investigate a role for specific medium-chain fatty acids (MCFAs) in reversing pathogenic outcomes. Drosophila larvae overexpressing the ALS-associated dipeptide repeats (DPRs) in the nervous system exhibit reduced motor function and neuromuscular junction (NMJ) defects. We show that two MCFAs, nonanoic acid (NA) and 4-methyloctanoic acid (4-MOA), can ameliorate impaired motor function in C9 larvae and improve NMJ degeneration, although their mechanisms of action are not identical. NA modified postsynaptic glutamate receptor density, whereas 4-MOA restored defects in the presynaptic vesicular release. We also demonstrate the effects of NA and 4-MOA on metabolism in C9 larvae and implicate various metabolic pathways as dysregulated in our ALS model. Our findings pave the way to identifying novel therapeutic targets and potential treatments for ALS.
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Affiliation(s)
- Ella Dunn
- Centre for Biomedical Sciences, Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 OEX, UK; (E.D.); (R.S.B.W.)
| | - Joern R. Steinert
- Faculty of Medicine & Health Sciences, Queen’s Medical Centre, Nottingham NG7 2UH, UK; (J.R.S.); (A.S.)
| | - Aelfwin Stone
- Faculty of Medicine & Health Sciences, Queen’s Medical Centre, Nottingham NG7 2UH, UK; (J.R.S.); (A.S.)
| | - Virender Sahota
- Centre for Biomedical Sciences, Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 OEX, UK; (E.D.); (R.S.B.W.)
| | - Robin S. B. Williams
- Centre for Biomedical Sciences, Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 OEX, UK; (E.D.); (R.S.B.W.)
| | - Stuart Snowden
- Centre for Biomedical Sciences, Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 OEX, UK; (E.D.); (R.S.B.W.)
| | - Hrvoje Augustin
- Centre for Biomedical Sciences, Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 OEX, UK; (E.D.); (R.S.B.W.)
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15
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Candia N, Ibacache A, Medina-Yáñez I, Olivares GH, Ramírez M, Vega-Macaya F, Couve A, Sierralta J, Olguín P. Identification of atlastin genetic modifiers in a model of hereditary spastic paraplegia in Drosophila. Hum Genet 2023; 142:1303-1315. [PMID: 37368047 DOI: 10.1007/s00439-023-02577-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 05/30/2023] [Indexed: 06/28/2023]
Abstract
Hereditary spastic paraplegias (HSPs) are a group of neurodegenerative disorders characterized by progressive dysfunction of corticospinal motor neurons. Mutations in Atlastin1/Spg3, a small GTPase required for membrane fusion in the endoplasmic reticulum, are responsible for 10% of HSPs. Patients with the same Atlastin1/Spg3 mutation present high variability in age at onset and severity, suggesting a fundamental role of the environment and genetic background. Here, we used a Drosophila model of HSPs to identify genetic modifiers of decreased locomotion associated with atlastin knockdown in motor neurons. First, we screened for genomic regions that modify the climbing performance or viability of flies expressing atl RNAi in motor neurons. We tested 364 deficiencies spanning chromosomes two and three and found 35 enhancer and four suppressor regions of the climbing phenotype. We found that candidate genomic regions can also rescue atlastin effects at synapse morphology, suggesting a role in developing or maintaining the neuromuscular junction. Motor neuron-specific knockdown of 84 genes spanning candidate regions of the second chromosome identified 48 genes required for climbing behavior in motor neurons and 7 for viability, mapping to 11 modifier regions. We found that atl interacts genetically with Su(z)2, a component of the Polycomb repressive complex 1, suggesting that epigenetic regulation plays a role in the variability of HSP-like phenotypes caused by atl alleles. Our results identify new candidate genes and epigenetic regulation as a mechanism modifying neuronal atl pathogenic phenotypes, providing new targets for clinical studies.
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Affiliation(s)
- Noemi Candia
- Programa de Genética Humana, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile
- Departamento de Neurociencia, Biomedical Neuroscience Institute (BNI), Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile
| | - Andrés Ibacache
- Departamento de Neurociencia, Biomedical Neuroscience Institute (BNI), Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile
| | - Ignacio Medina-Yáñez
- Programa de Genética Humana, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile
- Departamento de Neurociencia, Biomedical Neuroscience Institute (BNI), Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile
| | - Gonzalo H Olivares
- Departamento de Neurociencia, Biomedical Neuroscience Institute (BNI), Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile
- Escuela de Kinesiología, Facultad de Medicina y Ciencias de la Salud, Center for Integrative Biology (CIB), Universidad Mayor, Santiago, Chile
| | - Mauricio Ramírez
- Departamento de Neurociencia, Biomedical Neuroscience Institute (BNI), Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile
| | - Franco Vega-Macaya
- Programa de Genética Humana, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile
- Departamento de Neurociencia, Biomedical Neuroscience Institute (BNI), Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile
| | - Andrés Couve
- Departamento de Neurociencia, Biomedical Neuroscience Institute (BNI), Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile
| | - Jimena Sierralta
- Departamento de Neurociencia, Biomedical Neuroscience Institute (BNI), Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile
| | - Patricio Olguín
- Programa de Genética Humana, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile.
- Departamento de Neurociencia, Biomedical Neuroscience Institute (BNI), Facultad de Medicina, Universidad de Chile, Independencia 1027, 8380453, Santiago, Chile.
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16
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Pérez-Moreno JJ, Smith RC, Oliva MK, Gallo F, Ojha S, Müller KH, O’Kane CJ. Drosophila SPG12 ortholog, reticulon-like 1, governs presynaptic ER organization and Ca2+ dynamics. J Cell Biol 2023; 222:e202112101. [PMID: 36952540 PMCID: PMC10072275 DOI: 10.1083/jcb.202112101] [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: 12/22/2021] [Revised: 01/01/2023] [Accepted: 02/24/2023] [Indexed: 03/25/2023] Open
Abstract
Neuronal endoplasmic reticulum (ER) appears continuous throughout the cell. Its shape and continuity are influenced by ER-shaping proteins, mutations in which can cause distal axon degeneration in Hereditary Spastic Paraplegia (HSP). We therefore asked how loss of Rtnl1, a Drosophila ortholog of the human HSP gene RTN2 (SPG12), which encodes an ER-shaping protein, affects ER organization and the function of presynaptic terminals. Loss of Rtnl1 depleted ER membrane markers at Drosophila presynaptic motor terminals and appeared to deplete narrow tubular ER while leaving cisternae largely unaffected, thus suggesting little change in resting Ca2+ storage capacity. Nevertheless, these changes were accompanied by major reductions in activity-evoked Ca2+ fluxes in the cytosol, ER lumen, and mitochondria, as well as reduced evoked and spontaneous neurotransmission. We found that reduced STIM-mediated ER-plasma membrane contacts underlie presynaptic Ca2+ defects in Rtnl1 mutants. Our results show the importance of ER architecture in presynaptic physiology and function, which are therefore potential factors in the pathology of HSP.
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Affiliation(s)
| | | | - Megan K. Oliva
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Filomena Gallo
- Development and Neuroscience, Cambridge Advanced Imaging Centre, Cambridge, UK
| | - Shainy Ojha
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Karin H. Müller
- Development and Neuroscience, Cambridge Advanced Imaging Centre, Cambridge, UK
| | - Cahir J. O’Kane
- Department of Genetics, University of Cambridge, Cambridge, UK
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17
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Lei Y, Huang Y, Yang K, Cao X, Song Y, Martín-Blanco E, Pastor-Pareja JC. FGF signaling promotes spreading of fat body precursors necessary for adult adipogenesis in Drosophila. PLoS Biol 2023; 21:e3002050. [PMID: 36947563 PMCID: PMC10069774 DOI: 10.1371/journal.pbio.3002050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 04/03/2023] [Accepted: 02/24/2023] [Indexed: 03/23/2023] Open
Abstract
Knowledge of adipogenetic mechanisms is essential to understand and treat conditions affecting organismal metabolism and adipose tissue health. In Drosophila, mature adipose tissue (fat body) exists in larvae and adults. In contrast to the well-known development of the larval fat body from the embryonic mesoderm, adult adipogenesis has remained mysterious. Furthermore, conclusive proof of its physiological significance is lacking. Here, we show that the adult fat body originates from a pool of undifferentiated mesodermal precursors that migrate from the thorax into the abdomen during metamorphosis. Through in vivo imaging, we found that these precursors spread from the ventral midline and cover the inner surface of the abdomen in a process strikingly reminiscent of embryonic mesoderm migration, requiring fibroblast growth factor (FGF) signaling as well. FGF signaling guides migration dorsally and regulates adhesion to the substrate. After spreading is complete, precursor differentiation involves fat accumulation and cell fusion that produces mature binucleate and tetranucleate adipocytes. Finally, we show that flies where adult adipogenesis is impaired by knock down of FGF receptor Heartless or transcription factor Serpent display ectopic fat accumulation in oenocytes and decreased resistance to starvation. Our results reveal that adult adipogenesis occurs de novo during metamorphosis and demonstrate its crucial physiological role.
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Affiliation(s)
- Yuting Lei
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuwei Huang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Ke Yang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Xueya Cao
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuzhao Song
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Enrique Martín-Blanco
- Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Parc Científic de Barcelona, Barcelona, Spain
| | - José Carlos Pastor-Pareja
- School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
- Institute of Neurosciences, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, San Juan de Alicante, Spain
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18
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Scholz N, Dahse AK, Kemkemer M, Bormann A, Auger GM, Vieira Contreras F, Ernst LF, Staake H, Körner MB, Buhlan M, Meyer-Mölck A, Chung YK, Blanco-Redondo B, Klose F, Jarboui MA, Ljaschenko D, Bigl M, Langenhan T. Molecular sensing of mechano- and ligand-dependent adhesion GPCR dissociation. Nature 2023; 615:945-953. [PMID: 36890234 DOI: 10.1038/s41586-023-05802-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 02/06/2023] [Indexed: 03/10/2023]
Abstract
Adhesion G-protein-coupled receptors (aGPCRs) bear notable similarity to Notch proteins1, a class of surface receptors poised for mechano-proteolytic activation2-4, including an evolutionarily conserved mechanism of cleavage5-8. However, so far there is no unifying explanation for why aGPCRs are autoproteolytically processed. Here we introduce a genetically encoded sensor system to detect the dissociation events of aGPCR heterodimers into their constituent N-terminal and C-terminal fragments (NTFs and CTFs, respectively). An NTF release sensor (NRS) of the neural latrophilin-type aGPCR Cirl (ADGRL)9-11, from Drosophila melanogaster, is stimulated by mechanical force. Cirl-NRS activation indicates that receptor dissociation occurs in neurons and cortex glial cells. The release of NTFs from cortex glial cells requires trans-interaction between Cirl and its ligand, the Toll-like receptor Tollo (Toll-8)12, on neural progenitor cells, whereas expressing Cirl and Tollo in cis suppresses dissociation of the aGPCR. This interaction is necessary to control the size of the neuroblast pool in the central nervous system. We conclude that receptor autoproteolysis enables non-cell-autonomous activities of aGPCRs, and that the dissociation of aGPCRs is controlled by their ligand expression profile and by mechanical force. The NRS system will be helpful in elucidating the physiological roles and signal modulators of aGPCRs, which constitute a large untapped reservoir of drug targets for cardiovascular, immune, neuropsychiatric and neoplastic diseases13.
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Affiliation(s)
- Nicole Scholz
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany.
| | - Anne-Kristin Dahse
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Marguerite Kemkemer
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Anne Bormann
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Genevieve M Auger
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Fernando Vieira Contreras
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Lucia F Ernst
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Hauke Staake
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Marek B Körner
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Max Buhlan
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Amelie Meyer-Mölck
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Yin Kwan Chung
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Beatriz Blanco-Redondo
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Franziska Klose
- Core Facility for Medical Bioanalytics, Institute for Ophthalmic Research, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Mohamed Ali Jarboui
- Core Facility for Medical Bioanalytics, Institute for Ophthalmic Research, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Dmitrij Ljaschenko
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Marina Bigl
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Tobias Langenhan
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany.
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19
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Nemtsova Y, Steinert BL, Wharton KA. Compartment specific mitochondrial dysfunction in Drosophila knock-in model of ALS reversed by altered gene expression of OXPHOS subunits and pro-fission factor Drp1. Mol Cell Neurosci 2023; 125:103834. [PMID: 36868541 DOI: 10.1016/j.mcn.2023.103834] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 02/20/2023] [Accepted: 02/23/2023] [Indexed: 03/05/2023] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a fatal multisystem neurodegenerative disease, characterized by a loss in motor function. ALS is genetically diverse, with mutations in genes ranging from those regulating RNA metabolism, like TAR DNA-binding protein (TDP-43) and Fused in sarcoma (FUS), to those that act to maintain cellular redox homeostasis, like superoxide dismutase 1 (SOD1). Although varied in genetic origin, pathogenic and clinical commonalities are clearly evident between cases of ALS. Defects in mitochondria is one such common pathology, thought to occur prior to, rather than as a consequence of symptom onset, making these organelles a promising therapeutic target for ALS, as well as other neurodegenerative diseases. Depending on the homeostatic needs of neurons throughout life, mitochondria are normally shuttled to different subcellular compartments to regulate metabolite and energy production, lipid metabolism, and buffer calcium. While originally considered a motor neuron disease due to the dramatic loss in motor function accompanied by motor neuron cell death in ALS patients, many studies have now implicated non-motor neurons and glial cells alike. Defects in non-motor neuron cell types often preceed motor neuron death suggesting their dysfunction may initiate and/or facilitate the decline in motor neuron health. Here, we investigate mitochondria in a Drosophila Sod1 knock-in model of ALS. In depth, in vivo, examination reveals mitochondrial dysfunction evident prior to onset of motor neuron degeneration. Genetically encoded redox biosensors identify a general disruption in the electron transport chain (ETC). Compartment specific abnormalities in mitochondrial morphology is observed in diseased sensory neurons, accompanied by no apparent defects in the axonal transport machinery, but instead an increase in mitophagy in synaptic regions. The decrease in networked mitochondria at the synapse is reversed upon downregulation of the pro-fission factor Drp1. Furthermore, altered expression of specific OXPHOS subunits reverses ALS-associated defects in mitochondrial morphology and function.
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Affiliation(s)
- Y Nemtsova
- Molecular Biology, Cell Biology, and Biochemistry Department, Brown University, Providence, RI 02912, United States.
| | - B L Steinert
- Molecular Biology, Cell Biology, and Biochemistry Department, Brown University, Providence, RI 02912, United States.
| | - K A Wharton
- Molecular Biology, Cell Biology, and Biochemistry Department, Brown University, Providence, RI 02912, United States; Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI 02912, United States.
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20
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Xu W, Kong W, Gao Z, Huang E, Xie W, Wang S, Rui M. Establishment of a novel axon pruning model of Drosophila motor neuron. Biol Open 2023; 12:286282. [PMID: 36606515 PMCID: PMC9838636 DOI: 10.1242/bio.059535] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 11/30/2022] [Indexed: 01/07/2023] Open
Abstract
Developmental neuronal pruning is a process by which neurons selectively remove excessive or unnecessary neurite without causing neuronal death. Importantly, this process is widely used for the refinement of neural circuits in both vertebrates and invertebrates, and may also contribute to the pathogenesis of neuropsychiatric disorders, such as autism and schizophrenia. In the peripheral nervous system (PNS), class IV dendritic arborization (da) sensory neurons of Drosophila, selectively remove the dendrites without losing their somas and axons, while the dendrites and axons of mushroom body (MB) γ neuron in the central nervous system (CNS) are eliminated by localized fragmentation during metamorphosis. Alternatively, dendrite pruning of ddaC neurons is usually investigated via live-cell imaging, while dissection and fixation are currently used for evaluating MB γ neuron axon pruning. Thus, an excellent model system to assess axon specific pruning directly via live-cell imaging remains elusive. Here, we report that the Drosophila motor neuron offers a unique advantage for studying axon pruning. Interestingly, we uncover that long-range projecting axon bundle from soma at ventral nerve cord (VNC), undergoes degeneration rather than retraction during metamorphosis. Strikingly, the pruning process of the motor axon bundle is straightforward to investigate via live imaging and it occurs approximately at 22 h after pupal formation (APF), when axon bundles are completely cleared. Consistently, the classical axon pruning regulators in the Drosophila MB γ neuron, including TGF-β signaling, ecdysone signaling, JNK signaling, and the ubiquitin-proteasome system are also involved in governing motor axon pruning. Finally, our findings establish an unprecedented axon pruning mode that will serve to systematically screen and identify undiscovered axon pruning regulators. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Wanyue Xu
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Weiyu Kong
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Ziyang Gao
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Erqian Huang
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Wei Xie
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Su Wang
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China,Authors for correspondence (; )
| | - Menglong Rui
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, 2 Sipailou Road, Nanjing 210096, China,Authors for correspondence (; )
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21
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Ghosh AC, Hu Y, Tattikota SG, Liu Y, Comjean A, Perrimon N. Modeling exercise using optogenetically contractible Drosophila larvae. BMC Genomics 2022; 23:623. [PMID: 36042416 PMCID: PMC9425970 DOI: 10.1186/s12864-022-08845-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 08/16/2022] [Indexed: 11/10/2022] Open
Abstract
The pathophysiological effects of a number of metabolic and age-related disorders can be prevented to some extent by exercise and increased physical activity. However, the molecular mechanisms that contribute to the beneficial effects of muscle activity remain poorly explored. Availability of a fast, inexpensive, and genetically tractable model system for muscle activity and exercise will allow the rapid identification and characterization of molecular mechanisms that mediate the beneficial effects of exercise. Here, we report the development and characterization of an optogenetically-inducible muscle contraction (OMC) model in Drosophila larvae that we used to study acute exercise-like physiological responses. To characterize muscle-specific transcriptional responses to acute exercise, we performed bulk mRNA-sequencing, revealing striking similarities between acute exercise-induced genes in flies and those previously identified in humans. Our larval muscle contraction model opens a path for rapid identification and characterization of exercise-induced factors.
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Affiliation(s)
- Arpan C Ghosh
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
| | - Yanhui Hu
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | | | - Yifang Liu
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Aram Comjean
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
- Howard Hughes Medical Institute, Boston, MA, USA.
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22
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Paradis M, Kucharowski N, Edwards Faret G, Maya Palacios SJ, Meyer C, Stümpges B, Jamitzky I, Kalinowski J, Thiele C, Bauer R, Paululat A, Sellin J, Bülow MH. The ER protein Creld regulates ER-mitochondria contact dynamics and respiratory complex 1 activity. SCIENCE ADVANCES 2022; 8:eabo0155. [PMID: 35867795 PMCID: PMC9307246 DOI: 10.1126/sciadv.abo0155] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 06/07/2022] [Indexed: 05/26/2023]
Abstract
Dynamic contacts are formed between endoplasmic reticulum (ER) and mitochondria that enable the exchange of calcium and phospholipids. Disturbed contacts between ER and mitochondria impair mitochondrial dynamics and are a molecular hallmark of Parkinson's disease, which is also characterized by impaired complex I activity and dopaminergic neuron degeneration. Here, we analyzed the role of cysteine-rich with EGF-like domain (Creld), a poorly characterized risk gene for Parkinson's disease, in the regulation of mitochondrial dynamics and function. We found that loss of Creld leads to mitochondrial hyperfusion and reduced ROS signaling in Drosophila melanogaster, Xenopus tropicalis, and human cells. Creld fly mutants show differences in ER-mitochondria contacts and reduced respiratory complex I activity. The resulting low-hydrogen peroxide levels are linked to disturbed neuronal activity and lead to impaired locomotion, but not neurodegeneration, in Creld mutants. We conclude that Creld regulates ER-mitochondria communication and thereby hydrogen peroxide formation, which is required for normal neuron function.
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Affiliation(s)
- Marie Paradis
- Life and Medical Sciences (LIMES) Institute, University of Bonn, Carl-Troll-Straße 31, 53115 Bonn, Germany
| | - Nicole Kucharowski
- Life and Medical Sciences (LIMES) Institute, University of Bonn, Carl-Troll-Straße 31, 53115 Bonn, Germany
| | - Gabriela Edwards Faret
- Life and Medical Sciences (LIMES) Institute, University of Bonn, Carl-Troll-Straße 31, 53115 Bonn, Germany
- VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
| | | | - Christian Meyer
- Department of Zoology and Developmental Biology, University of Osnabrück, Barbarastr. 11, 49076 Osnabrück, Germany
| | - Birgit Stümpges
- Life and Medical Sciences (LIMES) Institute, University of Bonn, Carl-Troll-Straße 31, 53115 Bonn, Germany
| | - Isabell Jamitzky
- Life and Medical Sciences (LIMES) Institute, University of Bonn, Carl-Troll-Straße 31, 53115 Bonn, Germany
| | - Julia Kalinowski
- Life and Medical Sciences (LIMES) Institute, University of Bonn, Carl-Troll-Straße 31, 53115 Bonn, Germany
| | - Christoph Thiele
- Life and Medical Sciences (LIMES) Institute, University of Bonn, Carl-Troll-Straße 31, 53115 Bonn, Germany
| | - Reinhard Bauer
- Life and Medical Sciences (LIMES) Institute, University of Bonn, Carl-Troll-Straße 31, 53115 Bonn, Germany
| | - Achim Paululat
- Department of Zoology and Developmental Biology, University of Osnabrück, Barbarastr. 11, 49076 Osnabrück, Germany
| | - Julia Sellin
- Life and Medical Sciences (LIMES) Institute, University of Bonn, Carl-Troll-Straße 31, 53115 Bonn, Germany
- Institute for Digitalization and General Medicine, University Hospital Aachen, Pauwelsstr. 30, 52074 Aachen
| | - Margret Helene Bülow
- Life and Medical Sciences (LIMES) Institute, University of Bonn, Carl-Troll-Straße 31, 53115 Bonn, Germany
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23
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Kishino Y, Matsukawa K, Matsumoto T, Miyazaki R, Wakabayashi T, Nonaka T, Kametani F, Hasegawa M, Hashimoto T, Iwatsubo T. Casein kinase 1δ/ε phosphorylates fused in sarcoma (FUS) and ameliorates FUS-mediated neurodegeneration. J Biol Chem 2022; 298:102191. [PMID: 35753345 PMCID: PMC9293781 DOI: 10.1016/j.jbc.2022.102191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 12/03/2022] Open
Abstract
Aberrant cytoplasmic accumulation of an RNA-binding protein, fused in sarcoma (FUS), characterizes the neuropathology of subtypes of ALS and frontotemporal lobar degeneration, although the effects of post-translational modifications of FUS, especially phosphorylation, on its neurotoxicity have not been fully characterized. Here, we show that casein kinase 1δ (CK1δ) phosphorylates FUS at 10 serine/threonine residues in vitro using mass spectrometric analyses. We also show that phosphorylation by CK1δ or CK1ε significantly increased the solubility of FUS in human embryonic kidney 293 cells. In transgenic Drosophila that overexpress wt or P525L ALS-mutant human FUS in the retina or in neurons, we found coexpression of human CK1δ or its Drosophila isologue Dco in the photoreceptor neurons significantly ameliorated the observed retinal degeneration, and neuronal coexpression of human CK1δ extended fly life span. Taken together, our data suggest a novel regulatory mechanism of the assembly and toxicity of FUS through CK1δ/CK1ε-mediated phosphorylation, which could represent a potential therapeutic target in FUS proteinopathies.
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Affiliation(s)
- Yuya Kishino
- Department of Neuropathology, Graduate School of Medicine, The University of Tokyo; Department of Pathology, Graduate School of Medicine, The University of Tokyo; Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry
| | - Koji Matsukawa
- Department of Neuropathology, Graduate School of Medicine, The University of Tokyo
| | - Taisei Matsumoto
- Department of Neuropathology, Graduate School of Medicine, The University of Tokyo
| | - Ryota Miyazaki
- Department of Neuropathology, Graduate School of Medicine, The University of Tokyo; Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry
| | - Tomoko Wakabayashi
- Department of Neuropathology, Graduate School of Medicine, The University of Tokyo; Department of Innovative Dementia Prevention, Graduate School of Medicine, The University of Tokyo
| | - Takashi Nonaka
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science
| | - Fuyuki Kametani
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science
| | - Masato Hasegawa
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science
| | - Tadafumi Hashimoto
- Department of Neuropathology, Graduate School of Medicine, The University of Tokyo; Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry; Department of Innovative Dementia Prevention, Graduate School of Medicine, The University of Tokyo.
| | - Takeshi Iwatsubo
- Department of Neuropathology, Graduate School of Medicine, The University of Tokyo.
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24
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Sun X, Liu Y, Liu C, Mayumi K, Ito K, Nose A, Kohsaka H. A neuromechanical model for Drosophila larval crawling based on physical measurements. BMC Biol 2022; 20:130. [PMID: 35701821 PMCID: PMC9199175 DOI: 10.1186/s12915-022-01336-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 05/20/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Animal locomotion requires dynamic interactions between neural circuits, the body (typically muscles), and surrounding environments. While the neural circuitry of movement has been intensively studied, how these outputs are integrated with body mechanics (neuromechanics) is less clear, in part due to the lack of understanding of the biomechanical properties of animal bodies. Here, we propose an integrated neuromechanical model of movement based on physical measurements by taking Drosophila larvae as a model of soft-bodied animals. RESULTS We first characterized the kinematics of forward crawling in Drosophila larvae at a segmental and whole-body level. We then characterized the biomechanical parameters of fly larvae, namely the contraction forces generated by neural activity, and passive elastic and viscosity of the larval body using a stress-relaxation test. We established a mathematical neuromechanical model based on the physical measurements described above, obtaining seven kinematic values characterizing crawling locomotion. By optimizing the parameters in the neural circuit, our neuromechanical model succeeded in quantitatively reproducing the kinematics of larval locomotion that were obtained experimentally. This model could reproduce the observation of optogenetic studies reported previously. The model predicted that peristaltic locomotion could be exhibited in a low-friction condition. Analysis of floating larvae provided results consistent with this prediction. Furthermore, the model predicted a significant contribution of intersegmental connections in the central nervous system, which contrasts with a previous study. This hypothesis allowed us to make a testable prediction for the variability in intersegmental connection in sister species of the genus Drosophila. CONCLUSIONS We generated a neurochemical model based on physical measurement to provide a new foundation to study locomotion in soft-bodied animals and soft robot engineering.
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Affiliation(s)
- Xiyang Sun
- Department of Complexity Science and Engineering, Graduate School of Frontier Science, the University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Yingtao Liu
- Department of Physics, Graduate School of Science, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 133-0033, Japan
| | - Chang Liu
- Department of Advanced Materials Science, Graduate School of Frontier Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Koichi Mayumi
- Department of Advanced Materials Science, Graduate School of Frontier Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Kohzo Ito
- Department of Advanced Materials Science, Graduate School of Frontier Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Akinao Nose
- Department of Complexity Science and Engineering, Graduate School of Frontier Science, the University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan.,Department of Physics, Graduate School of Science, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 133-0033, Japan
| | - Hiroshi Kohsaka
- Department of Complexity Science and Engineering, Graduate School of Frontier Science, the University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan. .,Division of General Education, Graduate School of Informatics and Engineering, The University of Electro-Communications, 1-5-1, Chofugaoka, Chofu, Tokyo, 182-8585, Japan.
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25
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Paul MM, Dannhäuser S, Morris L, Mrestani A, Hübsch M, Gehring J, Hatzopoulos GN, Pauli M, Auger GM, Bornschein G, Scholz N, Ljaschenko D, Müller M, Sauer M, Schmidt H, Kittel RJ, DiAntonio A, Vakonakis I, Heckmann M, Langenhan T. The human cognition-enhancing CORD7 mutation increases active zone number and synaptic release. Brain 2022; 145:3787-3802. [DOI: 10.1093/brain/awac011] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/29/2021] [Accepted: 12/16/2021] [Indexed: 11/13/2022] Open
Abstract
Abstract
Humans carrying the CORD7 (cone-rod dystrophy 7) mutation possess increased verbal IQ and working memory. This autosomal dominant syndrome is caused by the single-amino acid R844H exchange (human numbering) located in the 310 helix of the C2A domain of RIMS1/RIM1 (Rab3-interacting molecule 1). RIM is an evolutionarily conserved multi-domain protein and essential component of presynaptic active zones, which is centrally involved in fast, Ca2+-triggered neurotransmitter release. How the CORD7 mutation affects synaptic function has remained unclear thus far. Here, we established Drosophila melanogaster as a disease model for clarifying the effects of the CORD7 mutation on RIM function and synaptic vesicle release.
To this end, using protein expression and X-ray crystallography, we solved the molecular structure of the Drosophila C2A domain at 1.92 Å resolution and by comparison to its mammalian homolog ascertained that the location of the CORD7 mutation is structurally conserved in fly RIM. Further, CRISPR/Cas9-assisted genomic engineering was employed for the generation of rim alleles encoding the R915H CORD7 exchange or R915E,R916E substitutions (fly numbering) to effect local charge reversal at the 310 helix. Through electrophysiological characterization by two-electrode voltage clamp and focal recordings we determined that the CORD7 mutation exerts a semi-dominant rather than a dominant effect on synaptic transmission resulting in faster, more efficient synaptic release and increased size of the readily releasable pool but decreased sensitivity for the fast calcium chelator BAPTA. In addition, the rim CORD7 allele increased the number of presynaptic active zones but left their nanoscopic organization unperturbed as revealed by super-resolution microscopy of the presynaptic scaffold protein Bruchpilot/ELKS/CAST.
We conclude that the CORD7 mutation leads to tighter release coupling, an increased readily releasable pool size and more release sites thereby promoting more efficient synaptic transmitter release. These results strongly suggest that similar mechanisms may underlie the CORD7 disease phenotype in patients and that enhanced synaptic transmission may contribute to their increased cognitive abilities.
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Affiliation(s)
- Mila M. Paul
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany
- Department of Orthopaedic Trauma, Hand, Plastic and Reconstructive Surgery, University Hospital of Würzburg, 97080 Würzburg, Germany
| | - Sven Dannhäuser
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany
| | - Lydia Morris
- Division of General Biochemistry, Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
| | - Achmed Mrestani
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany
- Division of General Biochemistry, Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
- Department of Neurology, Leipzig University Medical Center, 04103 Leipzig, Germany
| | - Martha Hübsch
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany
| | - Jennifer Gehring
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany
| | | | - Martin Pauli
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany
| | - Genevieve M. Auger
- Division of General Biochemistry, Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
| | - Grit Bornschein
- Carl Ludwig Institute of Physiology, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
| | - Nicole Scholz
- Division of General Biochemistry, Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
| | - Dmitrij Ljaschenko
- Division of General Biochemistry, Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
| | - Martin Müller
- Department of Molecular Life Sciences, University of Zürich, 8057 Zürich, Switzerland
| | - Markus Sauer
- Department of Biotechnology and Biophysics, University of Würzburg, 97074 Würzburg, Germany
| | - Hartmut Schmidt
- Carl Ludwig Institute of Physiology, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
| | - Robert J. Kittel
- Carl Ludwig Institute of Physiology, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
- Department of Animal Physiology, Institute of Biology, Leipzig University, 04103 Leipzig, Germany
| | - Aaron DiAntonio
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | | | - Manfred Heckmann
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany
| | - Tobias Langenhan
- Division of General Biochemistry, Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
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26
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Ho CH, Paolantoni C, Bawankar P, Tang Z, Brown S, Roignant J, Treisman JE. An exon junction complex-independent function of Barentsz in neuromuscular synapse growth. EMBO Rep 2022; 23:e53231. [PMID: 34726300 PMCID: PMC8728599 DOI: 10.15252/embr.202153231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 01/07/2023] Open
Abstract
The exon junction complex controls the translation, degradation, and localization of spliced mRNAs, and three of its core subunits also play a role in splicing. Here, we show that a fourth subunit, Barentsz, has distinct functions within and separate from the exon junction complex in Drosophila neuromuscular development. The distribution of mitochondria in larval muscles requires Barentsz as well as other exon junction complex subunits and is not rescued by a Barentsz transgene in which residues required for binding to the core subunit eIF4AIII are mutated. In contrast, interactions with the exon junction complex are not required for Barentsz to promote the growth of neuromuscular synapses. We find that the Activin ligand Dawdle shows reduced expression in barentsz mutants and acts downstream of Barentsz to control synapse growth. Both barentsz and dawdle are required in motor neurons, muscles, and glia for normal synapse growth, and exogenous Dawdle can rescue synapse growth in the absence of barentsz. These results identify a biological function for Barentsz that is independent of the exon junction complex.
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Affiliation(s)
- Cheuk Hei Ho
- Skirball Institute for Biomolecular Medicine and Department of Cell BiologyNYU School of MedicineNew YorkNYUSA
| | - Chiara Paolantoni
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and MedicineUniversity of LausanneLausanneSwitzerland
| | - Praveen Bawankar
- Institute of Pharmaceutical and Biomedical SciencesJohannes Gutenberg‐University MainzMainzGermany
| | - Zuojian Tang
- Center for Health Informatics and BioinformaticsNYU Langone Medical CenterNew YorkNYUSA
- Present address:
Computational Biology at Ridgefield US, Global Computational Biology and Digital ScienceBoehringer IngelheimRidgefieldCTUSA
| | - Stuart Brown
- Center for Health Informatics and BioinformaticsNYU Langone Medical CenterNew YorkNYUSA
- Present address:
ExxonMobil Corporate Strategic ResearchAnnandaleNJUSA
| | - Jean‐Yves Roignant
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and MedicineUniversity of LausanneLausanneSwitzerland
- Institute of Pharmaceutical and Biomedical SciencesJohannes Gutenberg‐University MainzMainzGermany
| | - Jessica E Treisman
- Skirball Institute for Biomolecular Medicine and Department of Cell BiologyNYU School of MedicineNew YorkNYUSA
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27
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Maiellaro I. In Vivo cAMP Dynamics in Drosophila Larval Neurons. Methods Mol Biol 2022; 2483:181-194. [PMID: 35286676 DOI: 10.1007/978-1-0716-2245-2_11] [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] [Indexed: 06/14/2023]
Abstract
Cyclic adenosine monophosphate (cAMP) is a universal second messenger that mediates a myriad of cell functions across all kingdoms of life.The ability to monitor intracellular changes of cAMP concentration in living cells using FRET-based biosensors is proving to be of paramount importance to unraveling the sophisticated organization of cAMP signaling.Here we describe the deployment of the fruit fly Drosophila melanogaster, specifically the third instar larval stage, as an in vivo model to study the spatio-temporal dynamics of cAMP in neurons. The ubiquity of cAMP signaling and conservation of fundamental mechanisms across species ensures relevance to vertebrate neurons while providing a more structurally and ethically simple model.
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Affiliation(s)
- Isabella Maiellaro
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, UK.
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28
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Maldonado-Díaz C, Vazquez M, Marie B. A comparison of three different methods of eliciting rapid activity-dependent synaptic plasticity at the Drosophila NMJ. PLoS One 2021; 16:e0260553. [PMID: 34847197 PMCID: PMC8631638 DOI: 10.1371/journal.pone.0260553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 11/11/2021] [Indexed: 11/29/2022] Open
Abstract
The Drosophila NMJ is a system of choice for investigating the mechanisms underlying the structural and functional modifications evoked during activity-dependent synaptic plasticity. Because fly genetics allows considerable versatility, many strategies can be employed to elicit this activity. Here, we compare three different stimulation methods for eliciting activity-dependent changes in structure and function at the Drosophila NMJ. We find that the method using patterned stimulations driven by a K+-rich solution creates robust structural modifications but reduces muscle viability, as assessed by resting potential and membrane resistance. We argue that, using this method, electrophysiological studies that consider the frequency of events, rather than their amplitude, are the only reliable studies. We contrast these results with the expression of CsChrimson channels and red-light stimulation at the NMJ, as well as with the expression of TRPA channels and temperature stimulation. With both these methods we observed reliable modifications of synaptic structures and consistent changes in electrophysiological properties. Indeed, we observed a rapid appearance of immature boutons that lack postsynaptic differentiation, and a potentiation of spontaneous neurotransmission frequency. Surprisingly, a patterned application of temperature changes alone is sufficient to provoke both structural and functional plasticity. In this context, temperature-dependent TRPA channel activation induces additional structural plasticity but no further increase in the frequency of spontaneous neurotransmission, suggesting an uncoupling of these mechanisms.
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Affiliation(s)
- Carolina Maldonado-Díaz
- Institute of Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
- Department of Anatomy & Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
| | - Mariam Vazquez
- Institute of Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
| | - Bruno Marie
- Institute of Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
- Department of Anatomy & Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
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Yang S, Constantin OM, Sachidanandan D, Hofmann H, Kunz TC, Kozjak-Pavlovic V, Oertner TG, Nagel G, Kittel RJ, Gee CE, Gao S. PACmn for improved optogenetic control of intracellular cAMP. BMC Biol 2021; 19:227. [PMID: 34663304 PMCID: PMC8522238 DOI: 10.1186/s12915-021-01151-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 09/10/2021] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Cyclic adenosine monophosphate (cAMP) is a ubiquitous second messenger that transduces extracellular signals in virtually all eukaryotic cells. The soluble Beggiatoa photoactivatable adenylyl cyclase (bPAC) rapidly raises cAMP in blue light and has been used to study cAMP signaling pathways cell-autonomously. But low activity in the dark might raise resting cAMP in cells expressing bPAC, and most eukaryotic cyclases are membrane-targeted rather than soluble. Our aim was to engineer a plasma membrane-anchored PAC with no dark activity (i.e., no cAMP accumulation in the dark) that rapidly increases cAMP when illuminated. RESULTS Using a streamlined method based on expression in Xenopus oocytes, we compared natural PACs and confirmed bPAC as the best starting point for protein engineering efforts. We identified several modifications that reduce bPAC dark activity. Mutating a phenylalanine to tyrosine at residue 198 substantially decreased dark cyclase activity, which increased 7000-fold when illuminated. Whereas Drosophila larvae expressing bPAC in mechanosensory neurons show nocifensive-like behavior even in the dark, larvae expressing improved soluble (e.g., bPAC(R278A)) and membrane-anchored PACs exhibited nocifensive responses only when illuminated. The plasma membrane-anchored PAC (PACmn) had an undetectable dark activity which increased >4000-fold in the light. PACmn does not raise resting cAMP nor, when expressed in hippocampal neurons, affect cAMP-dependent kinase (PKA) activity in the dark, but rapidly and reversibly increases cAMP and PKA activity in the soma and dendrites upon illumination. The peak responses to brief (2 s) light flashes exceed the responses to forskolin-induced activation of endogenous cyclases and return to baseline within seconds (cAMP) or ~10 min (PKA). CONCLUSIONS PACmn is a valuable optogenetic tool for precise cell-autonomous and transient stimulation of cAMP signaling pathways in diverse cell types.
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Affiliation(s)
- Shang Yang
- Department of Neurophysiology, Institute of Physiology, Biocenter, Julius-Maximilians-University of Würzburg, Röntgenring 9, 97070, Würzburg, Germany
| | - Oana M Constantin
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Divya Sachidanandan
- Department of Animal Physiology, Institute of Biology, Leipzig University, Talstraße 33, 04103, Leipzig, Germany.,Carl-Ludwig-Institute for Physiology, Leipzig University, Liebigstraße 27, 04103, Leipzig, Germany
| | - Hannes Hofmann
- Department of Animal Physiology, Institute of Biology, Leipzig University, Talstraße 33, 04103, Leipzig, Germany.,Carl-Ludwig-Institute for Physiology, Leipzig University, Liebigstraße 27, 04103, Leipzig, Germany
| | - Tobias C Kunz
- Department of Microbiology, Biocenter, Julius-Maximilians-University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Vera Kozjak-Pavlovic
- Department of Microbiology, Biocenter, Julius-Maximilians-University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Thomas G Oertner
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Georg Nagel
- Department of Neurophysiology, Institute of Physiology, Biocenter, Julius-Maximilians-University of Würzburg, Röntgenring 9, 97070, Würzburg, Germany
| | - Robert J Kittel
- Department of Animal Physiology, Institute of Biology, Leipzig University, Talstraße 33, 04103, Leipzig, Germany. .,Carl-Ludwig-Institute for Physiology, Leipzig University, Liebigstraße 27, 04103, Leipzig, Germany.
| | - Christine E Gee
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany.
| | - Shiqiang Gao
- Department of Neurophysiology, Institute of Physiology, Biocenter, Julius-Maximilians-University of Würzburg, Röntgenring 9, 97070, Würzburg, Germany.
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30
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Kim J, Kim S, Nahm M, Li TN, Lin HC, Kim YD, Lee J, Yao CK, Lee S. ALS2 regulates endosomal trafficking, postsynaptic development, and neuronal survival. J Cell Biol 2021; 220:e202007112. [PMID: 33683284 PMCID: PMC7944400 DOI: 10.1083/jcb.202007112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 01/07/2021] [Accepted: 02/11/2021] [Indexed: 12/11/2022] Open
Abstract
Mutations in the human ALS2 gene cause recessive juvenile-onset amyotrophic lateral sclerosis and related motor neuron diseases. Although the ALS2 protein has been identified as a guanine-nucleotide exchange factor for the small GTPase Rab5, its physiological roles remain largely unknown. Here, we demonstrate that the Drosophila homologue of ALS2 (dALS2) promotes postsynaptic development by activating the Frizzled nuclear import (FNI) pathway. dALS2 loss causes structural defects in the postsynaptic subsynaptic reticulum (SSR), recapitulating the phenotypes observed in FNI pathway mutants. Consistently, these developmental phenotypes are rescued by postsynaptic expression of the signaling-competent C-terminal fragment of Drosophila Frizzled-2 (dFz2). We further demonstrate that dALS2 directs early to late endosome trafficking and that the dFz2 C terminus is cleaved in late endosomes. Finally, dALS2 loss causes age-dependent progressive defects resembling ALS, including locomotor impairment and brain neurodegeneration, independently of the FNI pathway. These findings establish novel regulatory roles for dALS2 in endosomal trafficking, synaptic development, and neuronal survival.
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Affiliation(s)
- Joohyung Kim
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, Korea
- Department of Cell and Developmental Biology and Dental Research Institute, Seoul National University, Seoul, Korea
| | - Sungdae Kim
- Department of Cell and Developmental Biology and Dental Research Institute, Seoul National University, Seoul, Korea
| | - Minyeop Nahm
- Department of Cell and Developmental Biology and Dental Research Institute, Seoul National University, Seoul, Korea
| | - Tsai-Ning Li
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Hsin-Chieh Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Yeongjin David Kim
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, Korea
| | - Jihye Lee
- Department of Oral Pathology, Department of Life Science in Dentistry, Dental and Life Science Institute, School of Dentistry, Pusan National University, Yangsan, Korea
| | - Chi-Kuang Yao
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Neuroscience Program of Academia Sinica, Academia Sinica, Taipei, Taiwan
- Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Seungbok Lee
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, Korea
- Department of Cell and Developmental Biology and Dental Research Institute, Seoul National University, Seoul, Korea
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31
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Controlling the behaviour of Drosophila melanogaster via smartphone optogenetics. Sci Rep 2020; 10:17614. [PMID: 33077824 PMCID: PMC7572528 DOI: 10.1038/s41598-020-74448-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 09/24/2020] [Indexed: 01/05/2023] Open
Abstract
Invertebrates such as Drosophila melanogaster have proven to be a valuable model organism for studies of the nervous system. In order to control neuronal activity, optogenetics has evolved as a powerful technique enabling non-invasive stimulation using light. This requires light sources that can deliver patterns of light with high temporal and spatial precision. Currently employed light sources for stimulation of small invertebrates, however, are either limited in spatial resolution or require sophisticated and bulky equipment. In this work, we used smartphone displays for optogenetic control of Drosophila melanogaster. We developed an open-source smartphone app that allows time-dependent display of light patterns and used this to activate and inhibit different neuronal populations in both larvae and adult flies. Characteristic behavioural responses were observed depending on the displayed colour and brightness and in agreement with the activation spectra and light sensitivity of the used channelrhodopsins. By displaying patterns of light, we constrained larval movement and were able to guide larvae on the display. Our method serves as a low-cost high-resolution testbench for optogenetic experiments using small invertebrate species and is particularly appealing to application in neuroscience teaching labs.
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32
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POU domain motif3 (Pdm3) induces wingless (wg) transcription and is essential for development of larval neuromuscular junctions in Drosophila. Sci Rep 2020; 10:517. [PMID: 31949274 PMCID: PMC6965103 DOI: 10.1038/s41598-020-57425-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/31/2019] [Indexed: 02/07/2023] Open
Abstract
Wnt is a conserved family of secreted proteins that play diverse roles in tissue growth and differentiation. Identification of transcription factors that regulate wnt expression is pivotal for understanding tissue-specific signaling pathways regulated by Wnt. We identified pdm3m7, a new allele of the pdm3 gene encoding a POU family transcription factor, in a lethality-based genetic screen for modifiers of Wingless (Wg) signaling in Drosophila. Interestingly, pdm3m7 larvae showed slow locomotion, implying neuromuscular defects. Analysis of larval neuromuscular junctions (NMJs) revealed decreased bouton number with enlarged bouton in pdm3 mutants. pdm3 NMJs also had fewer branches at axon terminals than wild-type NMJs. Consistent with pdm3m7 being a candidate wg modifier, NMJ phenotypes in pdm3 mutants were similar to those of wg mutants, implying a functional link between these two genes. Indeed, lethality caused by Pdm3 overexpression in motor neurons was completely rescued by knockdown of wg, indicating that Pdm3 acts upstream to Wg. Furthermore, transient expression of Pdm3 induced ectopic expression of wg-LacZ reporter and Wg effector proteins in wing discs. We propose that Pdm3 expressed in presynaptic NMJ neurons regulates wg transcription for growth and development of both presynaptic neurons and postsynaptic muscles.
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33
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Konieczny P, Artero R. Drosophila SMN2 minigene reporter model identifies moxifloxacin as a candidate therapy for SMA. FASEB J 2019; 34:3021-3036. [PMID: 31909520 DOI: 10.1096/fj.201802554rrr] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 12/12/2019] [Accepted: 12/16/2019] [Indexed: 12/24/2022]
Abstract
Spinal muscular atrophy is a rare and fatal neuromuscular disorder caused by the loss of alpha motor neurons. The affected individuals have mutated the ubiquitously expressed SMN1 gene resulting in the loss or reduction in the survival motor neuron (SMN) protein levels. However, an almost identical paralog exists in humans: SMN2. Pharmacological activation of SMN2 exon 7 inclusion by small molecules or modified antisense oligonucleotides is a valid approach to treat SMA. Here we describe an in vivo SMN2 minigene reporter system in Drosophila motor neurons that serves as a cost-effective, feasible, and stringent primary screening model for identifying chemicals capable of crossing the conserved Drosophila blood-brain barrier and modulating exon 7 inclusion. The model was used for the screening of 1100 drugs from the Prestwick Chemical Library, resulting in 2.45% hit rate. The most promising candidate drugs were validated in patient-derived fibroblasts where they proved to increase SMN protein levels. Among them, moxifloxacin modulated SMN2 splicing by promoting exon 7 inclusion. The recovery of SMN protein levels was confirmed by increased colocalization of nuclear gems with Cajal Bodies. Thus, a Drosophila-based drug screen allowed the discovery of an FDA-approved small molecule with the potential to become a novel therapy for SMA.
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Affiliation(s)
- Piotr Konieczny
- Interdisciplinary Research Structure for Biotechnology and Biomedicine (ERI BIOTECMED), University of Valencia, Valencia, Spain.,Translational Genomics Group, Incliva Health Research Institute, Valencia, Spain.,Incliva-CIPF Joint Unit, Valencia, Spain
| | - Rubén Artero
- Interdisciplinary Research Structure for Biotechnology and Biomedicine (ERI BIOTECMED), University of Valencia, Valencia, Spain.,Translational Genomics Group, Incliva Health Research Institute, Valencia, Spain.,Incliva-CIPF Joint Unit, Valencia, Spain
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34
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González-Gutiérrez A, Ibacache A, Esparza A, Barros LF, Sierralta J. Neuronal lactate levels depend on glia-derived lactate during high brain activity in Drosophila. Glia 2019; 68:1213-1227. [PMID: 31876077 DOI: 10.1002/glia.23772] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 12/10/2019] [Accepted: 12/10/2019] [Indexed: 01/13/2023]
Abstract
Lactate/pyruvate transport between glial cells and neurons is thought to play an important role in how brain cells sustain the high-energy demand that neuronal activity requires. However, the in vivo mechanisms and characteristics that underlie the transport of monocarboxylates are poorly described. Here, we use Drosophila expressing genetically encoded FRET sensors to provide an ex vivo characterization of the transport of monocarboxylates in motor neurons and glial cells from the larval ventral nerve cord. We show that lactate/pyruvate transport in glial cells is coupled to protons and is more efficient than in neurons. Glial cells maintain higher levels of intracellular lactate generating a positive gradient toward neurons. Interestingly, during high neuronal activity, raised lactate in motor neurons is dependent on transfer from glial cells mediated in part by the previously described monocarboxylate transporter Chaski, providing support for in vivo glia-to-neuron lactate shuttling during neuronal activity.
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Affiliation(s)
- Andrés González-Gutiérrez
- Department of Neuroscience and Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Andrés Ibacache
- Department of Neuroscience and Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Andrés Esparza
- Department of Neuroscience and Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | | | - Jimena Sierralta
- Department of Neuroscience and Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
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35
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Hao Y, Waller TJ, Nye DM, Li J, Zhang Y, Hume RI, Rolls MM, Collins CA. Degeneration of Injured Axons and Dendrites Requires Restraint of a Protective JNK Signaling Pathway by the Transmembrane Protein Raw. J Neurosci 2019; 39:8457-8470. [PMID: 31492772 PMCID: PMC6807270 DOI: 10.1523/jneurosci.0016-19.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 08/08/2019] [Accepted: 08/22/2019] [Indexed: 12/15/2022] Open
Abstract
The degeneration of injured axons involves a self-destruction pathway whose components and mechanism are not fully understood. Here, we report a new regulator of axonal resilience. The transmembrane protein Raw is cell autonomously required for the degeneration of injured axons, dendrites, and synapses in Drosophila melanogaster In both male and female raw hypomorphic mutant or knock-down larvae, the degeneration of injured axons, dendrites, and synapses from motoneurons and sensory neurons is strongly inhibited. This protection is insensitive to reduction in the levels of the NAD+ synthesis enzyme Nmnat (nicotinamide mononucleotide adenylyl transferase), but requires the c-Jun N-terminal kinase (JNK) mitogen-activated protein (MAP) kinase and the transcription factors Fos and Jun (AP-1). Although these factors were previously known to function in axonal injury signaling and regeneration, Raw's function can be genetically separated from other axonal injury responses: Raw does not modulate JNK-dependent axonal injury signaling and regenerative responses, but instead restrains a protective pathway that inhibits the degeneration of axons, dendrites, and synapses. Although protection in raw mutants requires JNK, Fos, and Jun, JNK also promotes axonal degeneration. These findings suggest the existence of multiple independent pathways that share modulation by JNK, Fos, and Jun that influence how axons respond to stress and injury.SIGNIFICANCE STATEMENT Axonal degeneration is a major feature of neuropathies and nerve injuries and occurs via a cell autonomous self-destruction pathway whose mechanism is poorly understood. This study reports the identification of a new regulator of axonal degeneration: the transmembrane protein Raw. Raw regulates a cell autonomous nuclear signaling pathway whose yet unknown downstream effectors protect injured axons, dendrites, and synapses from degenerating. These findings imply that the susceptibility of axons to degeneration is strongly regulated in neurons. Future understanding of the cellular pathway regulated by Raw, which engages the c-Jun N-terminal kinase (JNK) mitogen-activated protein (MAP) kinase and Fos and Jun transcription factors, may suggest new strategies to increase the resiliency of axons in debilitating neuropathies.
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Affiliation(s)
- Yan Hao
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085
| | - Thomas J Waller
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085
| | - Derek M Nye
- Huck Institutes of the Life Sciences, and Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, and
| | - Jiaxing Li
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085
| | - Yanxiao Zhang
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109-2218
| | - Richard I Hume
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085
| | - Melissa M Rolls
- Huck Institutes of the Life Sciences, and Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, and
| | - Catherine A Collins
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085,
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Dulovic-Mahlow M, Trinh J, Kandaswamy KK, Braathen GJ, Di Donato N, Rahikkala E, Beblo S, Werber M, Krajka V, Busk ØL, Baumann H, Al-Sannaa NA, Hinrichs F, Affan R, Navot N, Al Balwi MA, Oprea G, Holla ØL, Weiss ME, Jamra RA, Kahlert AK, Kishore S, Tveten K, Vos M, Rolfs A, Lohmann K. De Novo Variants in TAOK1 Cause Neurodevelopmental Disorders. Am J Hum Genet 2019; 105:213-220. [PMID: 31230721 DOI: 10.1016/j.ajhg.2019.05.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 05/08/2019] [Indexed: 02/08/2023] Open
Abstract
De novo variants represent a significant cause of neurodevelopmental delay and intellectual disability. A genetic basis can be identified in only half of individuals who have neurodevelopmental disorders (NDDs); this indicates that additional causes need to be elucidated. We compared the frequency of de novo variants in patient-parent trios with (n = 2,030) versus without (n = 2,755) NDDs. We identified de novo variants in TAOK1 (thousand and one [TAO] amino acid kinase 1), which encodes the serine/threonine-protein kinase TAO1, in three individuals with NDDs but not in persons who did not have NDDs. Through further screening and the use of GeneMatcher, five additional individuals with NDDs were found to have de novo variants. All eight variants were absent from gnomAD (Genome Aggregation Database). The variant carriers shared a non-specific phenotype of developmental delay, and six individuals had additional muscular hypotonia. We established a fibroblast line of one mutation carrier, and we demonstrated that reduced mRNA levels of TAOK1 could be increased upon cycloheximide treatment. These results indicate nonsense-mediated mRNA decay. Further, there was neither detectable phosphorylated TAO1 kinase nor phosphorylated tau in these cells, and mitochondrial morphology was altered. Knockdown of the ortholog gene Tao1 (Tao, CG14217) in Drosophila resulted in delayed early development. The majority of the Tao1-knockdown flies did not survive beyond the third instar larval stage. When compared to control flies, Tao1 knockdown flies revealed changed morphology of the ventral nerve cord and the neuromuscular junctions as well as a decreased number of endings (boutons). Furthermore, mitochondria in mutant flies showed altered distribution and decreased size in axons of motor neurons. Thus, we provide compelling evidence that de novo variants in TAOK1 cause NDDs.
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Held A, Major P, Sahin A, Reenan RA, Lipscombe D, Wharton KA. Circuit Dysfunction in SOD1-ALS Model First Detected in Sensory Feedback Prior to Motor Neuron Degeneration Is Alleviated by BMP Signaling. J Neurosci 2019; 39:2347-2364. [PMID: 30659087 PMCID: PMC6433758 DOI: 10.1523/jneurosci.1771-18.2019] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 12/24/2018] [Accepted: 01/10/2019] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease for which the origin and underlying cellular defects are not fully understood. Although motor neuron degeneration is the signature feature of ALS, it is not clear whether motor neurons or other cells of the motor circuit are the site of disease initiation. To better understand the contribution of multiple cell types in ALS, we made use of a Drosophila Sod1G85R knock-in model, in which all cells harbor the disease allele. End-stage dSod1G85R animals of both sexes exhibit severe motor deficits with clear degeneration of motor neurons. Interestingly, earlier in dSod1G85R larvae, motor function is also compromised, but their motor neurons exhibit only subtle morphological and electrophysiological changes that are unlikely to cause the observed decrease in locomotion. We analyzed the intact motor circuit and identified a defect in sensory feedback that likely accounts for the altered motor activity of dSod1G85R We found cell-autonomous activation of bone morphogenetic protein signaling in proprioceptor sensory neurons which are critical for the relay of the contractile status of muscles back to the central nerve cord, completely rescues early-stage motor defects and partially rescue late-stage motor function to extend lifespan. Identification of a defect in sensory feedback as a potential initiating event in ALS motor dysfunction, coupled with the ability of modified proprioceptors to alleviate such motor deficits, underscores the critical role that nonmotor neurons play in disease progression and highlights their potential as a site to identify early-stage ALS biomarkers and for therapeutic intervention.SIGNIFICANCE STATEMENT At diagnosis, many cellular processes are already disrupted in the amyotrophic lateral sclerosis (ALS) patient. Identifying the initiating cellular events is critical for achieving an earlier diagnosis to slow or prevent disease progression. Our findings indicate that neurons relaying sensory information underlie early stage motor deficits in a Drosophila knock-in model of ALS that best replicates gene dosage in familial ALS (fALS). Importantly, studies on intact motor circuits revealed defects in sensory feedback before evidence of motor neuron degeneration. These findings strengthen our understanding of how neural circuit dysfunctions lead to neurodegeneration and, coupled with our demonstration that the activation of bone morphogenetic protein signaling in proprioceptors alleviates both early and late motor dysfunction, underscores the importance of considering nonmotor neurons as therapeutic targets.
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Affiliation(s)
- Aaron Held
- Department of Molecular Biology, Cell Biology and Biochemistry
- The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, Rhode Island 02912
| | - Paxton Major
- Department of Molecular Biology, Cell Biology and Biochemistry
| | - Asli Sahin
- Department of Molecular Biology, Cell Biology and Biochemistry
| | - Robert A Reenan
- Department of Molecular Biology, Cell Biology and Biochemistry
| | - Diane Lipscombe
- Department of Neuroscience, and
- The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, Rhode Island 02912
| | - Kristi A Wharton
- Department of Molecular Biology, Cell Biology and Biochemistry,
- The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, Rhode Island 02912
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38
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Draper I, Saha M, Stonebreaker H, Salomon RN, Matin B, Kang PB. The impact of Megf10/Drpr gain-of-function on muscle development in Drosophila. FEBS Lett 2019; 593:680-696. [PMID: 30802937 DOI: 10.1002/1873-3468.13348] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 02/12/2019] [Accepted: 02/13/2019] [Indexed: 11/07/2022]
Abstract
Recessive mutations in multiple epidermal growth factor-like domains 10 (MEGF10) underlie a rare congenital muscle disease known as MEGF10 myopathy. MEGF10 and its Drosophila homolog Draper (Drpr) are transmembrane receptors expressed in muscle and glia. Drpr deficiency is known to result in muscle abnormalities in flies. In the current study, flies that ubiquitously overexpress Drpr, or mouse Megf10, display developmental arrest. The phenotype is reproduced with overexpression in muscle, but not in other tissues, and with overexpression during intermediate stages of myogenesis, but not in myoblasts. We find that tubular muscle subtypes are particularly sensitive to Megf10/Drpr overexpression. Complementary genetic analyses show that Megf10/Drpr and Notch may interact to regulate myogenesis. Our findings provide a basis for investigating MEGF10 in muscle development using Drosophila.
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Affiliation(s)
- Isabelle Draper
- Department of Medicine, Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA, USA
| | - Madhurima Saha
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, USA
| | | | - Robert N Salomon
- Department of Pathology and Laboratory Medicine, Tufts Medical Center, Boston, MA, USA
| | - Bahar Matin
- Department of Medicine, Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA, USA
| | - Peter B Kang
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, USA.,Department of Neurology, Boston Children's Hospital, MA, USA.,Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, FL, USA.,Department of Neurology, University of Florida College of Medicine, Gainesville, FL, USA.,Genetics Institute and Myology Institute, University of Florida, Gainesville, FL, USA
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Scholz N, Ehmann N, Sachidanandan D, Imig C, Cooper BH, Jahn O, Reim K, Brose N, Meyer J, Lamberty M, Altrichter S, Bormann A, Hallermann S, Pauli M, Heckmann M, Stigloher C, Langenhan T, Kittel RJ. Complexin cooperates with Bruchpilot to tether synaptic vesicles to the active zone cytomatrix. J Cell Biol 2019; 218:1011-1026. [PMID: 30782781 PMCID: PMC6400551 DOI: 10.1083/jcb.201806155] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 12/14/2018] [Accepted: 01/09/2019] [Indexed: 02/06/2023] Open
Abstract
By performing an in vivo screen in Drosophila melanogaster, Scholz, Ehmann, et al. identify Complexin as a functional interaction partner of Bruchpilot. The two proteins mediate a physical attachment of synaptic vesicles to the active zone cytomatrix and promote rapid, sustained synaptic transmission. Information processing by the nervous system depends on neurotransmitter release from synaptic vesicles (SVs) at the presynaptic active zone. Molecular components of the cytomatrix at the active zone (CAZ) regulate the final stages of the SV cycle preceding exocytosis and thereby shape the efficacy and plasticity of synaptic transmission. Part of this regulation is reflected by a physical association of SVs with filamentous CAZ structures via largely unknown protein interactions. The very C-terminal region of Bruchpilot (Brp), a key component of the Drosophila melanogaster CAZ, participates in SV tethering. Here, we identify the conserved SNARE regulator Complexin (Cpx) in an in vivo screen for molecules that link the Brp C terminus to SVs. Brp and Cpx interact genetically and functionally. Both proteins promote SV recruitment to the Drosophila CAZ and counteract short-term synaptic depression. Analyzing SV tethering to active zone ribbons of cpx3 knockout mice supports an evolutionarily conserved role of Cpx upstream of SNARE complex assembly.
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Affiliation(s)
- Nicole Scholz
- Institute of Physiology, Department of Neurophysiology, University of Würzburg, Würzburg, Germany.,Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Leipzig University, Leipzig, Germany
| | - Nadine Ehmann
- Institute of Physiology, Department of Neurophysiology, University of Würzburg, Würzburg, Germany.,Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig, Germany.,Carl Ludwig Institute for Physiology, Leipzig University, Leipzig, Germany
| | - Divya Sachidanandan
- Institute of Physiology, Department of Neurophysiology, University of Würzburg, Würzburg, Germany
| | - Cordelia Imig
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Benjamin H Cooper
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Olaf Jahn
- Proteomics Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Kerstin Reim
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Jutta Meyer
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Proteomics Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics and Molecular Biosciences, University of Göttingen, Germany
| | - Marius Lamberty
- Institute of Physiology, Department of Neurophysiology, University of Würzburg, Würzburg, Germany.,Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig, Germany.,Carl Ludwig Institute for Physiology, Leipzig University, Leipzig, Germany
| | - Steffen Altrichter
- Institute of Physiology, Department of Neurophysiology, University of Würzburg, Würzburg, Germany.,Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Leipzig University, Leipzig, Germany
| | - Anne Bormann
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Leipzig University, Leipzig, Germany
| | - Stefan Hallermann
- Carl Ludwig Institute for Physiology, Leipzig University, Leipzig, Germany
| | - Martin Pauli
- Institute of Physiology, Department of Neurophysiology, University of Würzburg, Würzburg, Germany
| | - Manfred Heckmann
- Institute of Physiology, Department of Neurophysiology, University of Würzburg, Würzburg, Germany
| | | | - Tobias Langenhan
- Institute of Physiology, Department of Neurophysiology, University of Würzburg, Würzburg, Germany .,Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Leipzig University, Leipzig, Germany
| | - Robert J Kittel
- Institute of Physiology, Department of Neurophysiology, University of Würzburg, Würzburg, Germany .,Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig, Germany.,Carl Ludwig Institute for Physiology, Leipzig University, Leipzig, Germany
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40
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Beck S, Yu-Strzelczyk J, Pauls D, Constantin OM, Gee CE, Ehmann N, Kittel RJ, Nagel G, Gao S. Synthetic Light-Activated Ion Channels for Optogenetic Activation and Inhibition. Front Neurosci 2018; 12:643. [PMID: 30333716 PMCID: PMC6176052 DOI: 10.3389/fnins.2018.00643] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/29/2018] [Indexed: 01/21/2023] Open
Abstract
Optogenetic manipulation of cells or living organisms became widely used in neuroscience following the introduction of the light-gated ion channel channelrhodopsin-2 (ChR2). ChR2 is a non-selective cation channel, ideally suited to depolarize and evoke action potentials in neurons. However, its calcium (Ca2+) permeability and single channel conductance are low and for some applications longer-lasting increases in intracellular Ca2+ might be desirable. Moreover, there is need for an efficient light-gated potassium (K+) channel that can rapidly inhibit spiking in targeted neurons. Considering the importance of Ca2+ and K+ in cell physiology, light-activated Ca2+-permeant and K+-specific channels would be welcome additions to the optogenetic toolbox. Here we describe the engineering of novel light-gated Ca2+-permeant and K+-specific channels by fusing a bacterial photoactivated adenylyl cyclase to cyclic nucleotide-gated channels with high permeability for Ca2+ or for K+, respectively. Optimized fusion constructs showed strong light-gated conductance in Xenopus laevis oocytes and in rat hippocampal neurons. These constructs could also be used to control the motility of Drosophila melanogaster larvae, when expressed in motoneurons. Illumination led to body contraction when motoneurons expressed the light-sensitive Ca2+-permeant channel, and to body extension when expressing the light-sensitive K+ channel, both effectively and reversibly paralyzing the larvae. Further optimization of these constructs will be required for application in adult flies since both constructs led to eclosion failure when expressed in motoneurons.
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Affiliation(s)
- Sebastian Beck
- Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany
| | | | - Dennis Pauls
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Oana M Constantin
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christine E Gee
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nadine Ehmann
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany.,Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig, Germany.,Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig, Germany
| | - Robert J Kittel
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany.,Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig, Germany.,Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig, Germany
| | - Georg Nagel
- Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany
| | - Shiqiang Gao
- Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany
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41
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Furotani K, Kamimura K, Yajima T, Nakayama M, Enomoto R, Tamura T, Okazawa H, Sone M. Suppression of the synaptic localization of a subset of proteins including APP partially ameliorates phenotypes of the Drosophila Alzheimer's disease model. PLoS One 2018; 13:e0204048. [PMID: 30226901 PMCID: PMC6143267 DOI: 10.1371/journal.pone.0204048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 08/31/2018] [Indexed: 11/19/2022] Open
Abstract
APP (amyloid precursor protein), the causative molecule of Alzheimer's disease, is synthesized in neuronal cell bodies and subsequently transported to synapses. We previously showed that the yata gene is required for the synaptic transport of the APP orthologue in Drosophila melanogaster. In this study, we examined the effect of a reduction in yata expression in the Drosophila Alzheimer's disease model, in which expression of human mutant APP was induced. The synaptic localization of APP and other synaptic proteins was differentially inhibited by yata knockdown and null mutation. Expression of APP resulted in abnormal synaptic morphology and the premature death of animals. These phenotypes were partially but significantly rescued by yata knockdown, whereas yata knockdown itself caused no abnormality. Moreover, we observed that synaptic transmission accuracy was impaired in our model, and this phenotype was improved by yata knockdown. Thus, our data suggested that the phenotypes caused by APP can be partially prevented by inhibition of the synaptic localization of a subset of synaptic proteins including APP.
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Affiliation(s)
- Koto Furotani
- Faculty of Science, Toho University, Funabashi, Japan
| | | | | | | | - Rena Enomoto
- Faculty of Science, Toho University, Funabashi, Japan
| | - Takuya Tamura
- Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hitoshi Okazawa
- Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masaki Sone
- Faculty of Science, Toho University, Funabashi, Japan
- * E-mail:
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42
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C9orf72 Dipeptide Repeats Cause Selective Neurodegeneration and Cell-Autonomous Excitotoxicity in Drosophila Glutamatergic Neurons. J Neurosci 2018; 38:7741-7752. [PMID: 30037833 DOI: 10.1523/jneurosci.0908-18.2018] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 06/28/2018] [Accepted: 07/05/2018] [Indexed: 12/12/2022] Open
Abstract
The arginine-rich dipeptide repeats (DPRs) are highly toxic products from the C9orf72 repeat expansion mutations, which are the most common causes of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, the effects of DPRs in the synaptic regulation and excitotoxicity remain elusive, and how they contribute to the development of FTD is primarily unknown. By expressing DPRs with different toxicity strength in various neuronal populations in a Drosophila model, we unexpectedly found that Glycine-Arginine/Proline-Arginine (GR/PR) with 36 repeats could lead to neurodegenerative phenotypes only when they were expressed in glutamatergic neurons, including motor neurons. We detected increased extracellular glutamate and intracellular calcium levels in GR/PR-expressing larval ventral nerve cord and/or adult brain, accompanied by significant increase of synaptic boutons and active zones in larval neuromuscular junctions. Inhibiting the vesicular glutamate transporter expression or blocking the NMDA receptor in presynaptic glutamatergic motor neurons could effectively rescue the motor deficits and shortened life span caused by poly GR/PR, thus indicating a cell-autonomous excitotoxicity mechanism. Therefore, our results have revealed a novel mode of synaptic regulation by arginine-rich C9 DPRs expressed at more physiologically relevant toxicity levels and provided a mechanism that could contribute to the development of C9-related ALS and FTD.SIGNIFICANCE STATEMENT C9orf72 dipeptide repeats (DPRs) are key toxic species causing ALS/FTD, but their roles in synaptic regulation and excitotoxicity are unclear. Using C9orf72 DPRs with various toxicity strength, we have found that the arginine-rich DPRs cause selective degeneration in Drosophila glutamatergic neurons and revealed an NMDA receptor-dependent cell-autonomous excitotoxicity mechanism. Therefore, this study has advanced our understanding of C9orf72 DPR functions in synaptic regulation and excitotoxicity and provided a new mechanism that could contribute to the development of C9-related ALS and FTD.
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43
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dSTIM- and Ral/Exocyst-Mediated Synaptic Release from Pupal Dopaminergic Neurons Sustains Drosophila Flight. eNeuro 2018; 5:eN-NWR-0455-17. [PMID: 29938216 PMCID: PMC6011419 DOI: 10.1523/eneuro.0455-17.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 05/06/2018] [Accepted: 05/07/2018] [Indexed: 12/13/2022] Open
Abstract
Manifestation of appropriate behavior in adult animals requires developmental mechanisms that help in the formation of correctly wired neural circuits. Flight circuit development in Drosophila requires store-operated calcium entry (SOCE) through the STIM/Orai pathway. SOCE-associated flight deficits in adult Drosophila derive extensively from regulation of gene expression in pupal neurons, and one such SOCE-regulated gene encodes the small GTPase Ral. The cellular mechanism by which Ral helps in maturation of the flight circuit was not understood. Here, we show that knockdown of components of a Ral effector, the exocyst complex, in pupal neurons also leads to reduced flight bout durations, and this phenotype derives primarily from dopaminergic neurons. Importantly, synaptic release from pupal dopaminergic neurons is abrogated upon knockdown of dSTIM, Ral, or exocyst components. Ral overexpression restores the diminished synaptic release of dStim knockdown neurons as well as flight deficits associated with dSTIM knockdown in dopaminergic neurons. These results identify Ral-mediated vesicular release as an effector mechanism of neuronal SOCE in pupal dopaminergic neurons with functional consequences on flight behavior.
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44
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Molnar C, Estrada B, de Celis JF. Tay bridge and extracellular-regulated kinase activity are required for motoneuron function in the Drosophila neural system. GENES BRAIN AND BEHAVIOR 2018. [PMID: 29524312 DOI: 10.1111/gbb.12470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Extracellular regulated kinase (Erk) activity is required during neural development for the specification of cell fates in neuroblasts and neuronal lineages, and also regulates several aspects of the activity and survival of mature neurons. The activation of Erk is regulated at multiple levels by kinases and phosphatases that alter its phosphorylation state and by other proteins that regulate its subcellular localization. Here, we find that tay bridge (tay), a negative regulator of Erk in Drosophila imaginal discs, is required in the motoneurons to regulate the number and size of neuromuscular synapses in these cells. The expression of Tay is maximal in motoneurons with low levels of activated ERK, suggesting that Tay modulates the activity of Erk in these cells. We also found that loss of tay expression and increased Erk activity specifically in the motoneurons cause a reversible decrease in walking speed. Impaired motoneurons activity may be caused by alterations in the functionality and number of synaptic boutons developing at the neuromuscular junction in tay mutants.
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Affiliation(s)
- C Molnar
- Centro de Biología Molecular "Severo Ochoa", CSIC and Universidad Autónoma de Madrid, Madrid, Spain.,Institute for Research in Biomedicine-Barcelona, Barcelona, Spain
| | - B Estrada
- Centro Andaluz de Biología del Desarrollo, CSIC and UPO, Sevilla, Spain
| | - J F de Celis
- Centro de Biología Molecular "Severo Ochoa", CSIC and Universidad Autónoma de Madrid, Madrid, Spain
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45
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Backhaus P, Langenhan T, Neuser K. Effects of transgenic expression of botulinum toxins in Drosophila. J Neurogenet 2017; 30:22-31. [PMID: 27276193 DOI: 10.3109/01677063.2016.1166223] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Clostridial neurotoxins (botulinum toxins and tetanus toxin) disrupt neurotransmitter release by cleaving neuronal SNARE proteins. We generated transgenic flies allowing for conditional expression of different botulinum toxins and evaluated their potential as tools for the analysis of synaptic and neuronal network function in Drosophila melanogaster by applying biochemical assays and behavioral analysis. On the biochemical level, cleavage assays in cultured Drosophila S2 cells were performed and the cleavage efficiency was assessed via western blot analysis. We found that each botulinum toxin cleaves its Drosophila SNARE substrate but with variable efficiency. To investigate the cleavage efficiency in vivo, we examined lethality, larval peristaltic movements and vision dependent motion behavior of adult Drosophila after tissue-specific conditional botulinum toxin expression. Our results show that botulinum toxin type B and botulinum toxin type C represent effective alternatives to established transgenic effectors, i.e. tetanus toxin, interfering with neuronal and non-neuronal cell function in Drosophila and constitute valuable tools for the analysis of synaptic and network function.
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Affiliation(s)
- Philipp Backhaus
- a Department of Neurophysiology , Institute of Physiology, University of Würzburg , Würzburg , Germany
| | - Tobias Langenhan
- a Department of Neurophysiology , Institute of Physiology, University of Würzburg , Würzburg , Germany
| | - Kirsa Neuser
- a Department of Neurophysiology , Institute of Physiology, University of Würzburg , Würzburg , Germany ;,b Carl-Ludwig-Institute for Physiology, Medical Faculty , University of Leipzig , Leipzig , Germany
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46
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Bonneaud N, Layalle S, Colomb S, Jourdan C, Ghysen A, Severac D, Dantec C, Nègre N, Maschat F. Control of nerve cord formation by Engrailed and Gooseberry-Neuro: A multi-step, coordinated process. Dev Biol 2017; 432:273-285. [PMID: 29097190 DOI: 10.1016/j.ydbio.2017.10.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 10/06/2017] [Accepted: 10/24/2017] [Indexed: 01/05/2023]
Abstract
One way to better understand the molecular mechanisms involved in the construction of a nervous system is to identify the downstream effectors of major regulatory proteins. We previously showed that Engrailed (EN) and Gooseberry-Neuro (GsbN) transcription factors act in partnership to drive the formation of posterior commissures in the central nervous system of Drosophila. In this report, we identified genes regulated by both EN and GsbN through chromatin immunoprecipitation ("ChIP on chip") and transcriptome experiments, combined to a genetic screen relied to the gene dose titration method. The genomic-scale approaches allowed us to define 175 potential targets of EN-GsbN regulation. We chose a subset of these genes to examine ventral nerve cord (VNC) defects and found that half of the mutated targets show clear VNC phenotypes when doubly heterozygous with en or gsbn mutations, or when homozygous. This strategy revealed new groups of genes never described for their implication in the construction of the nerve cord. Their identification suggests that, to construct the nerve cord, EN-GsbN may act at three levels, in: (i) sequential control of the attractive-repulsive signaling that ensures contralateral projection of the commissural axons, (ii) temporal control of the translation of some mRNAs, (iii) regulation of the capability of glial cells to act as commissural guideposts for developing axons. These results illustrate how an early, coordinated transcriptional control may orchestrate the various mechanisms involved in the formation of stereotyped neuronal networks. They also validate the overall strategy to identify genes that play crucial role in axonal pathfinding.
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Affiliation(s)
- Nathalie Bonneaud
- MMDN, Univ. Montpellier, EPHE, INSERM, U1198, Montpellier, F-34095 France; CNRS,UPR1142, Institut de Génétique Humaine, Montpellier, F-34094, France
| | - Sophie Layalle
- CNRS,UPR1142, Institut de Génétique Humaine, Montpellier, F-34094, France; CNRS - INSERM - Université de Montpellier, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier F-34094, France
| | - Sophie Colomb
- CNRS,UPR1142, Institut de Génétique Humaine, Montpellier, F-34094, France
| | - Christophe Jourdan
- MMDN, Univ. Montpellier, EPHE, INSERM, U1198, Montpellier, F-34095 France
| | - Alain Ghysen
- MMDN, Univ. Montpellier, EPHE, INSERM, U1198, Montpellier, F-34095 France
| | - Dany Severac
- MGX - Montpellier GenomiX, Institut de Génomique Fonctionnelle, Montpellier F-34094, France
| | - Christelle Dantec
- MGX - Montpellier GenomiX, Institut de Génomique Fonctionnelle, Montpellier F-34094, France
| | - Nicolas Nègre
- DGIMI, INRA, Université de Montpellier, 34095 Montpellier, France; Institut Universitaire de France (IUF), Paris, France
| | - Florence Maschat
- MMDN, Univ. Montpellier, EPHE, INSERM, U1198, Montpellier, F-34095 France; CNRS,UPR1142, Institut de Génétique Humaine, Montpellier, F-34094, France.
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47
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Maiellaro I, Lohse MJ, Kittel RJ, Calebiro D. cAMP Signals in Drosophila Motor Neurons Are Confined to Single Synaptic Boutons. Cell Rep 2017; 17:1238-1246. [PMID: 27783939 PMCID: PMC5098120 DOI: 10.1016/j.celrep.2016.09.090] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 08/29/2016] [Accepted: 09/27/2016] [Indexed: 11/03/2022] Open
Abstract
The second messenger cyclic AMP (cAMP) plays an important role in synaptic plasticity. Although there is evidence for local control of synaptic transmission and plasticity, it is less clear whether a similar spatial confinement of cAMP signaling exists. Here, we suggest a possible biophysical basis for the site-specific regulation of synaptic plasticity by cAMP, a highly diffusible small molecule that transforms the physiology of synapses in a local and specific manner. By exploiting the octopaminergic system of Drosophila, which mediates structural synaptic plasticity via a cAMP-dependent pathway, we demonstrate the existence of local cAMP signaling compartments of micrometer dimensions within single motor neurons. In addition, we provide evidence that heterogeneous octopamine receptor localization, coupled with local differences in phosphodiesterase activity, underlies the observed differences in cAMP signaling in the axon, cell body, and boutons. Boutons, axon, and cell body are independent cAMP signaling compartments Receptors and PDEs are responsible for the compartmentalization of cAMP cAMP does not propagate from the bouton to the cell body Local cAMP increases provides a basis for site-specific control of synaptic plasticity
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Affiliation(s)
- Isabella Maiellaro
- Institute of Pharmacology and Toxicology and Rudolf Virchow Center, University of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany.
| | - Martin J Lohse
- Institute of Pharmacology and Toxicology and Rudolf Virchow Center, University of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany
| | - Robert J Kittel
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Röntgenring 9, 97070 Würzburg, Germany.
| | - Davide Calebiro
- Institute of Pharmacology and Toxicology and Rudolf Virchow Center, University of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany.
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48
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Santana E, Casas-Tintó S. Orb2 as modulator of Brat and their role at the neuromuscular junction. J Neurogenet 2017; 31:181-188. [PMID: 29105522 DOI: 10.1080/01677063.2017.1393539] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
How synapses are built and dismantled is a central question in neurobiology. A wide range of proteins and processes from gene transcription to protein degradation are involved. Orb2 regulates mRNA translation depending on its monomeric or oligomeric state to modulate nervous system development and memory. Orb2 is expressed in Drosophila larval brain and neuromuscular junction (NMJ), Orb2 knockdown causes a reduction of synapse number and defects in neuronal morphology. Brain tumor (Brat) is an Orb2 target; it is expressed in larval brain related with cell growth and proliferation. Brat downregulation induces an increase in synapse number and abnormal growth of buttons and branches in neurons. In absence of Orb2, Brat is overexpressed suggesting that Orb2 is negatively regulating Brat mRNA translation. Orb2 or Brat control the expression of specific genes related to neuronal function. Orb2 is required for Liprin and Synaptobrevin transcription meanwhile Brat is required for Synaptobrevin and Synaptotagmin transcription. We present here evidences of a novel genetic mechanism to regulate synapse fine tuning during development and propose an equilibrium between Orb2 conformational state and nervous system formation.
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49
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De Gregorio C, Delgado R, Ibacache A, Sierralta J, Couve A. Drosophila Atlastin in motor neurons is required for locomotion and presynaptic function. J Cell Sci 2017; 130:3507-3516. [PMID: 28860117 DOI: 10.1242/jcs.201657] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 08/29/2017] [Indexed: 01/22/2023] Open
Abstract
Hereditary spastic paraplegias (HSPs) are characterized by spasticity and weakness of the lower limbs, resulting from length-dependent axonopathy of the corticospinal tracts. In humans, the HSP-related atlastin genes ATL1-ATL3 catalyze homotypic membrane fusion of endoplasmic reticulum (ER) tubules. How defects in neuronal Atlastin contribute to axonal degeneration has not been explained satisfactorily. Using Drosophila, we demonstrate that downregulation or overexpression of Atlastin in motor neurons results in decreased crawling speed and contraction frequency in larvae, while adult flies show progressive decline in climbing ability. Broad expression in the nervous system is required to rescue the atlastin-null Drosophila mutant (atl2 ) phenotype. Importantly, both spontaneous release and the reserve pool of synaptic vesicles are affected. Additionally, axonal secretory organelles are abnormally distributed, whereas presynaptic proteins diminish at terminals and accumulate in distal axons, possibly in lysosomes. Our findings suggest that trafficking defects produced by Atlastin dysfunction in motor neurons result in redistribution of presynaptic components and aberrant mobilization of synaptic vesicles, stressing the importance of ER-shaping proteins and the susceptibility of motor neurons to their mutations or depletion.
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Affiliation(s)
- Cristian De Gregorio
- Department of Neuroscience, Universidad de Chile, Santiago CP8380453, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
| | - Ricardo Delgado
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago CP7800003, Chile
| | - Andrés Ibacache
- Department of Neuroscience, Universidad de Chile, Santiago CP8380453, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
| | - Jimena Sierralta
- Department of Neuroscience, Universidad de Chile, Santiago CP8380453, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
| | - Andrés Couve
- Department of Neuroscience, Universidad de Chile, Santiago CP8380453, Chile .,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago CP8380453, Chile
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50
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Restoration of Motor Defects Caused by Loss of Drosophila TDP-43 by Expression of the Voltage-Gated Calcium Channel, Cacophony, in Central Neurons. J Neurosci 2017; 37:9486-9497. [PMID: 28847811 DOI: 10.1523/jneurosci.0554-17.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 08/17/2017] [Accepted: 08/19/2017] [Indexed: 01/08/2023] Open
Abstract
Defects in the RNA-binding protein, TDP-43, are known to cause a variety of neurodegenerative diseases, including amyotrophic lateral sclerosis and frontotemporal lobar dementia. A variety of experimental systems have shown that neurons are sensitive to TDP-43 expression levels, yet the specific functional defects resulting from TDP-43 dysregulation have not been well described. Using the Drosophila TDP-43 ortholog TBPH, we previously showed that TBPH-null animals display locomotion defects as third instar larvae. Furthermore, loss of TBPH caused a reduction in cacophony, a Type II voltage-gated calcium channel, expression and that genetically restoring cacophony in motor neurons in TBPH mutant animals was sufficient to rescue the locomotion defects. In the present study, we examined the relative contributions of neuromuscular junction physiology and the motor program to the locomotion defects and identified subsets of neurons that require cacophony expression to rescue the defects. At the neuromuscular junction, we showed mEPP amplitudes and frequency require TBPH. Cacophony expression in motor neurons rescued mEPP frequency but not mEPP amplitude. We also showed that TBPH mutants displayed reduced motor neuron bursting and coordination during crawling and restoring cacophony selectively in two pairs of cells located in the brain, the AVM001b/2b neurons, also rescued the locomotion and motor defects, but not the defects in neuromuscular junction physiology. These results suggest that the behavioral defects associated with loss of TBPH throughout the nervous system can be associated with defects in a small number of genes in a limited number of central neurons, rather than peripheral defects.SIGNIFICANCE STATEMENT TDP-43 dysfunction is a common feature in neurodegenerative diseases, including amyotrophic lateral sclerosis, frontotemporal lobar dementia, and Alzheimer's disease. Loss- and gain-of-function models have shown that neurons are sensitive to TDP-43 expression levels, but the specific defects caused by TDP-43 loss of function have not been described in detail. A Drosophila loss-of-function model displays pronounced locomotion defects that can be reversed by restoring the expression levels of a voltage-gated calcium channel, cacophony. We show these defects can be rescued by expression of cacophony in motor neurons and by expression in two pairs of neurons in the brain. These data suggest that loss of TDP-43 can disrupt the central circuitry of the CNS, opening up identification of alternative therapeutic targets for TDP-43 proteinopathies.
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