1
|
Ikegami Y, Duenki T, Arakaki I, Sakai R, Osaki T, Ashihara S, Furushima T, Ikeuchi Y. A simple and inexpensive laser dissection of fasciculated axons from motor nerve organoids. Front Bioeng Biotechnol 2024; 12:1259138. [PMID: 38347914 PMCID: PMC10859526 DOI: 10.3389/fbioe.2024.1259138] [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: 07/15/2023] [Accepted: 01/15/2024] [Indexed: 02/15/2024] Open
Abstract
Motor nerve organoids could be generated by culturing a spheroid of motor neurons differentiated from human induced pluripotent stem (iPS) cells within a polydimethylsiloxane (PDMS) chip which guides direction and fasciculation of axons extended from the spheroid. To isolate axon bundles from motor nerve organoids, we developed a rapid laser dissection method based on localized photothermal combustion. By illuminating a blue laser on a black mark on the culture device using a dry-erase marker, we induced highly localized heating near the axon bundles. Moving the laser enabled spatial control over the local heating and severing of axon bundles. This laser dissection requires a black mark, as other colors did not produce the same localized heating effect. A CO2 laser destroyed the tissue and the device and could not be used. With this simple, economical laser dissection technique, we could rapidly collect abundant pure axon samples from motor nerve organoids for biochemical analysis. Extracted axonal proteins and RNA were indistinguishable from manual dissection. This method facilitates efficient axon isolation for further analyses.
Collapse
Affiliation(s)
- Yasuhiro Ikegami
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan
- Institute for AI and Beyond, The University of Tokyo, Tokyo, Japan
| | - Tomoya Duenki
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan
- Institute for AI and Beyond, The University of Tokyo, Tokyo, Japan
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
- Laboratory for Integrated Micro Mechatronic Systems, National Center for Scientific Research-Institute of Industrial Science (LIMMS/CNRS-IIS), The University of Tokyo, Tokyo, Japan
| | - Ikuma Arakaki
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Ryo Sakai
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Tatsuya Osaki
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan
- Institute for AI and Beyond, The University of Tokyo, Tokyo, Japan
| | - Satoshi Ashihara
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan
| | | | - Yoshiho Ikeuchi
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan
- Institute for AI and Beyond, The University of Tokyo, Tokyo, Japan
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
- Laboratory for Integrated Micro Mechatronic Systems, National Center for Scientific Research-Institute of Industrial Science (LIMMS/CNRS-IIS), The University of Tokyo, Tokyo, Japan
| |
Collapse
|
2
|
de León A, Gibon J, Barker PA. APP Genetic Deficiency Alters Intracellular Ca 2+ Homeostasis and Delays Axonal Degeneration in Dorsal Root Ganglion Sensory Neurons. J Neurosci 2022; 42:6680-6691. [PMID: 35882556 PMCID: PMC9436018 DOI: 10.1523/jneurosci.0162-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 06/08/2022] [Accepted: 07/11/2022] [Indexed: 11/21/2022] Open
Abstract
The activation of self-destructive cellular programs helps sculpt the nervous system during development, but the molecular mechanisms used are not fully understood. Prior studies have investigated the role of the APP in the developmental degeneration of sensory neurons with contradictory results. In this work, we sought to elucidate the impact of APP deletion in the development of the sensory nervous system in vivo and in vitro. Our in vivo data show an increase in the number of sciatic nerve axons in adult male and female APP-null mice, consistent with the hypothesis that APP plays a pro-degenerative role in the development of peripheral axons. In vitro, we show that genetic deletion of APP delays axonal degeneration triggered by nerve growth factor deprivation, indicating that APP does play a pro-degenerative role. Interestingly, APP depletion does not affect caspase-3 levels but significantly attenuates the rise of axoplasmic Ca2+ that occurs during degeneration. We examined intracellular Ca2+ mechanisms that could be involved and found that APP-null DRG neurons had increased Ca2+ levels within the endoplasmic reticulum and enhanced store-operated Ca2+ entry. We also observed that DRG axons lacking APP have more mitochondria than their WT counterparts, but these display a lower mitochondrial membrane potential. Finally, we present evidence that APP deficiency causes an increase in mitochondrial Ca2+ buffering capacity. Our results support the hypothesis that APP plays a pro-degenerative role in the developmental degeneration of DRG sensory neurons, and unveil the importance of APP in the regulation of calcium signaling in sensory neurons.SIGNIFICANCE STATEMENT The nervous system goes through a phase of pruning and programmed neuronal cell death during development to reach maturity. In such context, the role played by the APP in the peripheral nervous system has been controversial, ranging from pro-survival to pro-degenerative. Here we present evidence in vivo and in vitro supporting the pro-degenerative role of APP, demonstrating the ability of APP to alter intracellular Ca2+ homeostasis and mitochondria, critical players of programmed cell death. This work provides a better understanding of the physiological function of APP and its implication in developmental neuronal death in the nervous system.
Collapse
Affiliation(s)
- Andrés de León
- University of British Columbia Okanagan, Kelowna, British Columbia V1V 1V7, Canada
| | - Julien Gibon
- University of British Columbia Okanagan, Kelowna, British Columbia V1V 1V7, Canada
| | - Philip A Barker
- University of British Columbia Okanagan, Kelowna, British Columbia V1V 1V7, Canada
| |
Collapse
|
3
|
Kievit B, Johnstone AD, Gibon J, Barker PA. Mitochondrial Reactive Oxygen Species Mediate Activation of TRPV1 and Calcium Entry Following Peripheral Sensory Axotomy. Front Mol Neurosci 2022; 15:852181. [PMID: 35370552 PMCID: PMC8973397 DOI: 10.3389/fnmol.2022.852181] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 02/17/2022] [Indexed: 12/03/2022] Open
Abstract
Axons that are physically separated from their soma activate a series of signaling events that results in axonal self-destruction. A critical element of this signaling pathway is an intra-axonal calcium rise that occurs just prior to axonal fragmentation. Previous studies have shown that preventing this calcium rise delays the onset of axon fragmentation, yet the ion channels responsible for the influx, and the mechanisms by which they are activated, are largely unknown. Axonal injury can be modeled in vitro by transecting murine dorsal root ganglia (DRG) sensory axons. We coupled transections with intra-axonal calcium imaging and found that Ca2+ influx is sharply reduced in axons lacking trpv1 (for transient receptor potential cation channel vanilloid 1) and in axons treated with capsazepine (CPZ), a TRPV1 antagonist. Sensory neurons from trpv1–/– mice were partially rescued from degeneration after transection, indicating that TRPV1 normally plays a pro-degenerative role after axonal injury. TRPV1 activity can be regulated by direct post-translational modification induced by reactive oxygen species (ROS). Here, we tested the hypothesis that mitochondrial ROS production induced by axotomy is required for TRPV1 activity and subsequent axonal degeneration. We found that reducing mitochondrial depolarization with NAD+ supplementation or scavenging ROS using NAC or MitoQ sharply attenuates TRPV1-dependent calcium influx induced by axotomy. This study shows that ROS-dependent TRPV1 activation is required for Ca2+ entry after axotomy.
Collapse
Affiliation(s)
- Bradley Kievit
- Department of Biology, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Aaron D. Johnstone
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Julien Gibon
- Department of Biology, University of British Columbia Okanagan, Kelowna, BC, Canada
- *Correspondence: Julien Gibon,
| | - Philip A. Barker
- Department of Biology, University of British Columbia Okanagan, Kelowna, BC, Canada
- Philip A. Barker,
| |
Collapse
|
4
|
Wiatr K, Marczak Ł, Pérot JB, Brouillet E, Flament J, Figiel M. Broad Influence of Mutant Ataxin-3 on the Proteome of the Adult Brain, Young Neurons, and Axons Reveals Central Molecular Processes and Biomarkers in SCA3/MJD Using Knock-In Mouse Model. Front Mol Neurosci 2021; 14:658339. [PMID: 34220448 PMCID: PMC8248683 DOI: 10.3389/fnmol.2021.658339] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/01/2021] [Indexed: 01/11/2023] Open
Abstract
Spinocerebellar ataxia type 3 (SCA3/MJD) is caused by CAG expansion mutation resulting in a long polyQ domain in mutant ataxin-3. The mutant protein is a special type of protease, deubiquitinase, which may indicate its prominent impact on the regulation of cellular proteins levels and activity. Yet, the global model picture of SCA3 disease progression on the protein level, molecular pathways in the brain, and neurons, is largely unknown. Here, we investigated the molecular SCA3 mechanism using an interdisciplinary research paradigm combining behavioral and molecular aspects of SCA3 in the knock-in ki91 model. We used the behavior, brain magnetic resonance imaging (MRI) and brain tissue examination to correlate the disease stages with brain proteomics, precise axonal proteomics, neuronal energy recordings, and labeling of vesicles. We have demonstrated that altered metabolic and mitochondrial proteins in the brain and the lack of weight gain in Ki91 SCA3/MJD mice is reflected by the failure of energy metabolism recorded in neonatal SCA3 cerebellar neurons. We have determined that further, during disease progression, proteins responsible for metabolism, cytoskeletal architecture, vesicular, and axonal transport are disturbed, revealing axons as one of the essential cell compartments in SCA3 pathogenesis. Therefore we focus on SCA3 pathogenesis in axonal and somatodendritic compartments revealing highly increased axonal localization of protein synthesis machinery, including ribosomes, translation factors, and RNA binding proteins, while the level of proteins responsible for cellular transport and mitochondria was decreased. We demonstrate the accumulation of axonal vesicles in neonatal SCA3 cerebellar neurons and increased phosphorylation of SMI-312 positive adult cerebellar axons, which indicate axonal dysfunction in SCA3. In summary, the SCA3 disease mechanism is based on the broad influence of mutant ataxin-3 on the neuronal proteome. Processes central in our SCA3 model include disturbed localization of proteins between axonal and somatodendritic compartment, early neuronal energy deficit, altered neuronal cytoskeletal structure, an overabundance of various components of protein synthesis machinery in axons.
Collapse
Affiliation(s)
- Kalina Wiatr
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
| | - Łukasz Marczak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
| | - Jean-Baptiste Pérot
- Université Paris-Saclay, Centre National de la Recherche Scientifique, Commissariat à l'Energie Atomique, Direction de la Recherche Fondamentale, Institut de Biologie François Jacob, Molecular Imaging Research Center, Neurodegenerative Diseases Laboratory, Fontenay-aux-Roses, France
| | - Emmanuel Brouillet
- Université Paris-Saclay, Centre National de la Recherche Scientifique, Commissariat à l'Energie Atomique, Direction de la Recherche Fondamentale, Institut de Biologie François Jacob, Molecular Imaging Research Center, Neurodegenerative Diseases Laboratory, Fontenay-aux-Roses, France
| | - Julien Flament
- Université Paris-Saclay, Centre National de la Recherche Scientifique, Commissariat à l'Energie Atomique, Direction de la Recherche Fondamentale, Institut de Biologie François Jacob, Molecular Imaging Research Center, Neurodegenerative Diseases Laboratory, Fontenay-aux-Roses, France
| | - Maciej Figiel
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
| |
Collapse
|
5
|
NGF-Dependent and BDNF-Dependent DRG Sensory Neurons Deploy Distinct Degenerative Signaling Mechanisms. eNeuro 2021; 8:ENEURO.0277-20.2020. [PMID: 33372032 PMCID: PMC7877462 DOI: 10.1523/eneuro.0277-20.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 02/07/2023] Open
Abstract
The nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are trophic factors required by distinct population of sensory neurons during development of the nervous system. Neurons that fail to receive appropriate trophic support are lost during this period of naturally occurring cell death. In the last decade, our understanding of the signaling pathways regulating neuronal death following NGF deprivation has advanced substantially. However, the signaling mechanisms promoting BDNF deprivation-induced sensory neuron degeneration are largely unknown. Using a well-established in vitro culture model of dorsal root ganglion (DRG), we have examined degeneration mechanisms triggered on BDNF withdrawal in sensory neurons. Our results indicate differences and similarities between the molecular signaling pathways behind NGF and BDNF deprivation-induced death. For instance, we observed that the inhibition of Trk receptors (K252a), PKC (Gö6976), protein translation (cycloheximide; CHX), or caspases (zVAD-fmk) provides protection from NGF deprivation-induced death but not from degeneration evoked by BDNF-withdrawal. Interestingly, degeneration of BDNF-dependent sensory neurons requires BAX and appears to rely on reactive oxygen species (ROS) generation rather than caspases to induce degeneration. These results highlight the complexity and divergence of mechanisms regulating developmental sensory neuron death.
Collapse
|
6
|
Girouard MP, Simas T, Hua L, Morquette B, Khazaei MR, Unsain N, Johnstone AD, Rambaldi I, Sanz RL, Di Raddo ME, Gamage KK, Yong Y, Willis DE, Verge VMK, Barker PA, Deppmann C, Fournier AE. Collapsin Response Mediator Protein 4 (CRMP4) Facilitates Wallerian Degeneration and Axon Regeneration following Sciatic Nerve Injury. eNeuro 2020; 7:ENEURO.0479-19.2020. [PMID: 32001550 PMCID: PMC7053045 DOI: 10.1523/eneuro.0479-19.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/14/2020] [Accepted: 01/15/2020] [Indexed: 11/29/2022] Open
Abstract
In contrast to neurons in the CNS, damaged neurons from the peripheral nervous system (PNS) regenerate, but this process can be slow and imperfect. Successful regeneration is orchestrated by cytoskeletal reorganization at the tip of the proximal axon segment and cytoskeletal disassembly of the distal segment. Collapsin response mediator protein 4 (CRMP4) is a cytosolic phospho-protein that regulates the actin and microtubule cytoskeleton. During development, CRMP4 promotes growth cone formation and dendrite development. Paradoxically, in the adult CNS, CRMP4 impedes axon regeneration. Here, we investigated the involvement of CRMP4 in peripheral nerve injury in male and female Crmp4-/- mice following sciatic nerve injury. We find that sensory axon regeneration and Wallerian degeneration are impaired in Crmp4-/- mice following sciatic nerve injury. In vitro analysis of dissociated dorsal root ganglion (DRG) neurons from Crmp4-/- mice revealed that CRMP4 functions in the proximal axon segment to promote the regrowth of severed DRG neurons and in the distal axon segment where it facilitates Wallerian degeneration through calpain-dependent formation of harmful CRMP4 fragments. These findings reveal an interesting dual role for CRMP4 in proximal and distal axon segments of injured sensory neurons that coordinately facilitate PNS axon regeneration.
Collapse
Affiliation(s)
- Marie-Pier Girouard
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | - Tristan Simas
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | - Luyang Hua
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | - Barbara Morquette
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | - Mohamad R Khazaei
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | - Nicolas Unsain
- Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 5016 Córdoba, Argentina
| | - Aaron D Johnstone
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | - Isabel Rambaldi
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | - Ricardo L Sanz
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| | | | - Kanchana K Gamage
- Department of Biology, University of Virginia, Charlottesville, Virginia 22903
| | - Yu Yong
- Department of Biology, University of Virginia, Charlottesville, Virginia 22903
| | - Dianna E Willis
- Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York 10065
- Burke Institute, Weill Cornell Medicine, White Plains, New York 10605
| | - Valerie M K Verge
- Department of Anatomy, Physiology and Pharmacology, University of Saskatchewan-CMSNRC, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Philip A Barker
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
- Department of Biology, University of British Columbia, Kelowna, British Columbia V1V 1V7, Canada
| | | | - Alyson E Fournier
- Department of Neurology and Neurosurgery, Montréal Neurological Institute and Hospital, Montréal, Québec H3A 2B4, Canada
| |
Collapse
|
7
|
Wang H, Wang X, Zhang K, Wang Q, Cao X, Wang Z, Zhang S, Li A, Liu K, Fang Y. Rapid depletion of ESCRT protein Vps4 underlies injury-induced autophagic impediment and Wallerian degeneration. SCIENCE ADVANCES 2019; 5:eaav4971. [PMID: 30788439 PMCID: PMC6374107 DOI: 10.1126/sciadv.aav4971] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 01/02/2019] [Indexed: 06/01/2023]
Abstract
Injured axons undergo a controlled, self-destruction process, known as Wallerian degeneration. However, the underlying mechanism remains elusive. Using the Drosophila wing nerve as a model, we identify the ESCRT component Vps4 as a previously unidentified essential gene for axonal integrity. Up-regulation of Vps4 remarkably delays degeneration of injured axons. We further reveal that Vps4 is required and sufficient to promote autophagic flux in axons and mammalian cells. Moreover, using both in vitro and in vivo models, we show that the function of Vps4 in maintaining axonal autophagy and suppressing Wallerian degeneration is conserved in mammals. Last, we uncover that Vps4 protein is rapidly depleted in injured mouse axons, which may underlie the injury-induced autophagic impediment and the subsequent axonal degeneration. Together, Vps4 and ESCRT may represent a novel signal transduction mechanism in axon injury and Wallerian degeneration.
Collapse
Affiliation(s)
- Haiqiong Wang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuejie Wang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
- Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, The Hong Kong University of Science and Technology, Hong Kong, China
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University–The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China
| | - Kai Zhang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qingyao Wang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xu Cao
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhao Wang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
| | - Shuang Zhang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
| | - Ang Li
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Joint International Research Laboratory of CNS Regeneration Ministry of Education, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Jinan University, Guangzhou 510632, China
| | - Kai Liu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
- Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, The Hong Kong University of Science and Technology, Hong Kong, China
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University–The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China
| | - Yanshan Fang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 201210, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
8
|
The Nogo Receptor Ligand LGI1 Regulates Synapse Number and Synaptic Activity in Hippocampal and Cortical Neurons. eNeuro 2018; 5:eN-NWR-0185-18. [PMID: 30225353 PMCID: PMC6140115 DOI: 10.1523/eneuro.0185-18.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/31/2018] [Accepted: 08/14/2018] [Indexed: 12/20/2022] Open
Abstract
Leucine-rich glioma-inactivated protein 1 (LGI1) is a secreted neuronal protein and a Nogo receptor 1 (NgR1) ligand. Mutations in LGI1 in humans causes autosomal dominant lateral temporal lobe epilepsy and homozygous deletion of LGI1 in mice results in severe epileptic seizures that cause early postnatal death. NgR1 plays an important role in the development of CNS synapses and circuitry by limiting plasticity in the adult cortex via the activation of RhoA. These relationships and functions prompted us to examine the effect of LGI1 on synapse formation in vitro and in vivo. We report that application of LGI1 increases synaptic density in neuronal culture and that LGI1 null hippocampus has fewer dendritic mushroom spines than in wild-type (WT) littermates. Further, our electrophysiological investigations demonstrate that LGI1 null hippocampal neurons possess fewer and weaker synapses. RhoA activity is significantly increased in cortical cultures derived from LGI1 null mice and using a reconstituted system; we show directly that LGI1 antagonizes NgR1-tumor necrosis factor receptor orphan Y (TROY) signaling. Our data suggests that LGI1 enhances synapse formation in cortical and hippocampal neurons by reducing NgR1 signaling.
Collapse
|
9
|
Johnstone AD, Hallett RM, de Léon A, Carturan B, Gibon J, Barker PA. A novel method for quantifying axon degeneration. PLoS One 2018; 13:e0199570. [PMID: 30020957 PMCID: PMC6051587 DOI: 10.1371/journal.pone.0199570] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/08/2018] [Indexed: 11/25/2022] Open
Abstract
Axons normally degenerate during development of the mammalian nervous system, but dysregulation of the same genetically-encoded destructive cellular machinery can destroy crucial structures during adult neurodegenerative diseases. Nerve growth factor (NGF) withdrawal from dorsal root ganglia (DRG) axons is a well-established in vitro experimental model for biochemical and cell biological studies of developmental degeneration. Definitive methods for measuring axon degeneration have been lacking and here we report a novel method of axon degeneration quantification from bulk cultures of DRG that enables objective and automated measurement of axonal density over the entire field of radial axon outgrowth from the ganglion. As proof of principal, this new method, written as an R script called Axoquant 2.0, was used to examine the role of extracellular Ca2+ in the execution of cytoskeletal disassembly during degeneration of NGF-deprived DRG axons. This method can be easily applied to examine degenerative or neuroprotective effects of gene manipulations and pharmacological interventions.
Collapse
Affiliation(s)
- Aaron D. Johnstone
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
- Department of Biology, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Robin M. Hallett
- The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Andrés de Léon
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
- Department of Biology, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Bruno Carturan
- Department of Biology, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Julien Gibon
- Department of Biology, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Philip A. Barker
- Department of Biology, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| |
Collapse
|
10
|
Maciel R, Bis DM, Rebelo AP, Saghira C, Züchner S, Saporta MA. The human motor neuron axonal transcriptome is enriched for transcripts related to mitochondrial function and microtubule-based axonal transport. Exp Neurol 2018; 307:155-163. [PMID: 29935168 DOI: 10.1016/j.expneurol.2018.06.008] [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: 11/22/2017] [Revised: 06/05/2018] [Accepted: 06/15/2018] [Indexed: 10/28/2022]
Abstract
Local axonal translation of specific mRNA species plays an important role in axon maintenance, plasticity during development and recovery from injury. Recently, disrupted axonal mRNA transport and translation have been linked to neurodegenerative disorders. To identify mRNA species that are actively transported to axons and play an important role in axonal physiology, we mapped the axonal transcriptome of human induced pluripotent stem cell (iPSC)-derived motor neurons using permeable inserts to obtain large amounts of enriched axonal material for RNA isolation and sequencing. Motor neurons from healthy subjects were used to determine differences in gene expression profiles between neuronal somatodendritic and axonal compartments. Our results demonstrate that several transcripts were enriched in either the axon or neuronal bodies. Gene ontology analysis demonstrated enrichment in the axonal compartment for transcripts associated with mitochondrial electron transport, microtubule-based axonal transport and ER-associated protein catabolism. These results suggest that local translation of mRNAs is required to meet the high-energy demand of axons and to support microtubule-based axonal transport. Interestingly, several transcripts related to human genetic disorders associated with axonal degeneration (inherited axonopathies) were identified among the mRNA species enriched in motor axons.
Collapse
Affiliation(s)
- Renata Maciel
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Dana M Bis
- Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Adriana P Rebelo
- Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Cima Saghira
- Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Stephan Züchner
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Mario A Saporta
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| |
Collapse
|
11
|
Larhammar M, Huntwork-Rodriguez S, Rudhard Y, Sengupta-Ghosh A, Lewcock JW. The Ste20 Family Kinases MAP4K4, MINK1, and TNIK Converge to Regulate Stress-Induced JNK Signaling in Neurons. J Neurosci 2017; 37:11074-11084. [PMID: 28993483 PMCID: PMC6596808 DOI: 10.1523/jneurosci.0905-17.2017] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 09/13/2017] [Accepted: 10/02/2017] [Indexed: 11/21/2022] Open
Abstract
The c-Jun-N-terminal kinase (JNK) signaling pathway regulates nervous system development, axon regeneration, and neuronal degeneration after acute injury or in chronic neurodegenerative disease. Dual leucine zipper kinase (DLK) is required for stress-induced JNK signaling in neurons, yet the factors that initiate DLK/JNK pathway activity remain poorly defined. In the present study, we identify the Ste20 kinases MAP4K4, misshapen-like kinase 1 (MINK1 or MAP4K6) and TNIK Traf2- and Nck-interacting kinase (TNIK or MAP4K7), as upstream regulators of DLK/JNK signaling in neurons. Using a trophic factor withdrawal-based model of neurodegeneration in both male and female embryonic mouse dorsal root ganglion neurons, we show that MAP4K4, MINK1, and TNIK act redundantly to regulate DLK activation and downstream JNK-dependent phosphorylation of c-Jun in response to stress. Targeting MAP4K4, MINK1, and TNIK, but not any of these kinases individually, is sufficient to protect neurons potently from degeneration. Pharmacological inhibition of MAP4Ks blocks stabilization and phosphorylation of DLK within axons and subsequent retrograde translocation of the JNK signaling complex to the nucleus. These results position MAP4Ks as important regulators of the DLK/JNK signaling pathway.SIGNIFICANCE STATEMENT Neuronal degeneration occurs in disparate circumstances: during development to refine neuronal connections, after injury to clear damaged neurons, or pathologically during disease. The dual leucine zipper kinase (DLK)/c-Jun-N-terminal kinase (JNK) pathway represents a conserved regulator of neuronal injury signaling that drives both neurodegeneration and axon regeneration, yet little is known about the factors that initiate DLK activity. Here, we uncover a novel role for a subfamily of MAP4 kinases consisting of MAP4K4, Traf2- and Nck-interacting kinase (TNIK or MAP4K7), and misshapen-like kinase 1 (MINK1 or MAP4K6) in regulating DLK/JNK signaling in neurons. Inhibition of these MAP4Ks blocks stress-induced retrograde JNK signaling and protects from neurodegeneration, suggesting that these kinases may represent attractive therapeutic targets.
Collapse
Affiliation(s)
- Martin Larhammar
- Department of Neuroscience, Genentech, Inc., San Francisco, California 94080
- Denali Therapeutics Inc., South San Francisco, California 94080
| | - Sarah Huntwork-Rodriguez
- Department of Neuroscience, Genentech, Inc., San Francisco, California 94080
- Denali Therapeutics Inc., South San Francisco, California 94080
| | - York Rudhard
- In Vitro Pharmacology, Evotec AG, Manfred Eigen Campus, 22419 Hamburg, Germany, and
| | | | - Joseph W Lewcock
- Department of Neuroscience, Genentech, Inc., San Francisco, California 94080,
- Denali Therapeutics Inc., South San Francisco, California 94080
| |
Collapse
|
12
|
Larhammar M, Huntwork-Rodriguez S, Jiang Z, Solanoy H, Sengupta Ghosh A, Wang B, Kaminker JS, Huang K, Eastham-Anderson J, Siu M, Modrusan Z, Farley MM, Tessier-Lavigne M, Lewcock JW, Watkins TA. Dual leucine zipper kinase-dependent PERK activation contributes to neuronal degeneration following insult. eLife 2017; 6. [PMID: 28440222 PMCID: PMC5404924 DOI: 10.7554/elife.20725] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 03/20/2017] [Indexed: 01/24/2023] Open
Abstract
The PKR-like endoplasmic reticulum kinase (PERK) arm of the Integrated Stress Response (ISR) is implicated in neurodegenerative disease, although the regulators and consequences of PERK activation following neuronal injury are poorly understood. Here we show that PERK signaling is a component of the mouse MAP kinase neuronal stress response controlled by the Dual Leucine Zipper Kinase (DLK) and contributes to DLK-mediated neurodegeneration. We find that DLK-activating insults ranging from nerve injury to neurotrophin deprivation result in both c-Jun N-terminal Kinase (JNK) signaling and the PERK- and ISR-dependent upregulation of the Activating Transcription Factor 4 (ATF4). Disruption of PERK signaling delays neurodegeneration without reducing JNK signaling. Furthermore, DLK is both sufficient for PERK activation and necessary for engaging the ISR subsequent to JNK-mediated retrograde injury signaling. These findings identify DLK as a central regulator of not only JNK but also PERK stress signaling in neurons, with both pathways contributing to neurodegeneration.
Collapse
Affiliation(s)
- Martin Larhammar
- Department of Neuroscience, Genentech, Inc., San Francisco, United States
| | | | - Zhiyu Jiang
- Department of Neuroscience, Genentech, Inc., San Francisco, United States
| | - Hilda Solanoy
- Department of Neuroscience, Genentech, Inc., San Francisco, United States
| | | | - Bei Wang
- Department of Neuroscience, Genentech, Inc., San Francisco, United States
| | | | - Kevin Huang
- Bioinformatics, Genentech, Inc., San Francisco, United States
| | | | - Michael Siu
- Discovery Chemistry, Genentech, Inc., San Francisco, United States
| | - Zora Modrusan
- Molecular Biology, Genentech, Inc., San Francisco, United States
| | - Madeline M Farley
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas
| | - Marc Tessier-Lavigne
- Department of Neuroscience, Genentech, Inc., San Francisco, United States.,Laboratory of Brain Development and Repair, The Rockefeller University, New York, United States
| | - Joseph W Lewcock
- Department of Neuroscience, Genentech, Inc., San Francisco, United States
| | - Trent A Watkins
- Department of Neuroscience, Genentech, Inc., San Francisco, United States.,Department of Neurosurgery, Baylor College of Medicine, Houston, Texas.,OMNI Biomarkers Development, Genentech, Inc., San Francisco, United States
| |
Collapse
|
13
|
Unsain N, Barker PA. New Views on the Misconstrued: Executioner Caspases and Their Diverse Non-apoptotic Roles. Neuron 2016; 88:461-74. [PMID: 26539888 DOI: 10.1016/j.neuron.2015.08.029] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Initially characterized for their roles in apoptosis, executioner caspases have emerged as important regulators of an array of cellular activities. This is especially true in the nervous system, where sublethal caspase activity has been implicated in axonal pathfinding and branching, axonal degeneration, dendrite pruning, regeneration, long-term depression, and metaplasticity. Here we examine the roles of sublethal executioner caspase activity in nervous system development and maintenance, consider the mechanisms that locally activate and restrain these potential killers, and discuss how their activity be subverted in neurodegenerative disease.
Collapse
Affiliation(s)
- Nicolas Unsain
- Laboratorio de Neurobiología, Instituto de Investigación Médica Mercedes y Martín Ferreyra, Instituto Nacional de Investigación Médica Córdoba-Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Córdoba, Friuli 2434, Córdoba (5016), Argentina
| | - Philip A Barker
- Irving K. Barber School of Arts and Sciences, University of British Columbia, Kelowna, BC V1V 1V7, Canada.
| |
Collapse
|