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Li X, Saiyin H, Chen X, Yu Q, Ma L, Liang W. Ketamine impairs growth cone and synaptogenesis in human GABAergic projection neurons via GSK-3β and HDAC6 signaling. Mol Psychiatry 2024; 29:1647-1659. [PMID: 36414713 DOI: 10.1038/s41380-022-01864-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 11/23/2022]
Abstract
The growth cone guides the axon or dendrite of striatal GABAergic projection neurons that protrude into the midbrain and cortex and form complex neuronal circuits and synaptic networks in a developing brain, aberrant projections and synaptic connections in the striatum related to multiple brain disorders. Previously, we showed that ketamine, an anesthetic, reduced dendritic growth, dendritic branches, and spine density in human striatal GABAergic neurons. However, whether ketamine affects the growth cone, the synaptic connection of growing striatal GABAergic neurons has not been tested. Using human GABAergic projection neurons derived from human inducible pluripotent stem cells (hiPSCs) and embryonic stem cells (ES) in vitro, we tested ketamine effects on the growth cones and synapses in developing GABAergic neurons by assessing the morphometry and the glycogen synthase kinase-3 (GSK-3) and histone deacetylase 6 (HDAC6) pathway. Ketamine exposure impairs growth cone formation, synaptogenesis, dendritic development, and maturation via ketamine-mediated activation of GSK-3 pathways and inhibiting HDAC6, an essential stabilizing protein for dendritic morphogenesis and synapse maturation. Our findings identified a novel ketamine neurotoxic pathway that depends on GSK-3β and HDAC6 signaling, suggesting that microtubule acetylation is a potential target for reducing ketamine's toxic effect on GABAergic projection neuronal development.
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Affiliation(s)
- Xuan Li
- Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, China
- Department of Anesthesiology, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, Guangdong, China
| | - Hexige Saiyin
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Xinyu Chen
- Department of Anatomy and Histology & Embryology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Qiong Yu
- Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, China.
| | - Lixiang Ma
- Department of Anatomy and Histology & Embryology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
| | - Weimin Liang
- Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, China.
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2
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Garrido JJ. Contribution of Axon Initial Segment Structure and Channels to Brain Pathology. Cells 2023; 12:cells12081210. [PMID: 37190119 DOI: 10.3390/cells12081210] [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: 04/01/2023] [Revised: 04/17/2023] [Accepted: 04/20/2023] [Indexed: 05/17/2023] Open
Abstract
Brain channelopathies are a group of neurological disorders that result from genetic mutations affecting ion channels in the brain. Ion channels are specialized proteins that play a crucial role in the electrical activity of nerve cells by controlling the flow of ions such as sodium, potassium, and calcium. When these channels are not functioning properly, they can cause a wide range of neurological symptoms such as seizures, movement disorders, and cognitive impairment. In this context, the axon initial segment (AIS) is the site of action potential initiation in most neurons. This region is characterized by a high density of voltage-gated sodium channels (VGSCs), which are responsible for the rapid depolarization that occurs when the neuron is stimulated. The AIS is also enriched in other ion channels, such as potassium channels, that play a role in shaping the action potential waveform and determining the firing frequency of the neuron. In addition to ion channels, the AIS contains a complex cytoskeletal structure that helps to anchor the channels in place and regulate their function. Therefore, alterations in this complex structure of ion channels, scaffold proteins, and specialized cytoskeleton may also cause brain channelopathies not necessarily associated with ion channel mutations. This review will focus on how the AISs structure, plasticity, and composition alterations may generate changes in action potentials and neuronal dysfunction leading to brain diseases. AIS function alterations may be the consequence of voltage-gated ion channel mutations, but also may be due to ligand-activated channels and receptors and AIS structural and membrane proteins that support the function of voltage-gated ion channels.
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Affiliation(s)
- Juan José Garrido
- Instituto Cajal, CSIC, 28002 Madrid, Spain
- Alzheimer's Disease and Other Degenerative Dementias, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), 28002 Madrid, Spain
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3
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CDK5/p35-Dependent Microtubule Reorganization Contributes to Homeostatic Shortening of the Axon Initial Segment. J Neurosci 2023; 43:359-372. [PMID: 36639893 PMCID: PMC9864565 DOI: 10.1523/jneurosci.0917-22.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 10/13/2022] [Accepted: 10/18/2022] [Indexed: 12/12/2022] Open
Abstract
The structural plasticity of the axon initial segment (AIS) contributes to the homeostatic control of activity and optimizes the function of neural circuits; however, the underlying mechanisms are not fully understood. In this study, we prepared a slice culture containing nucleus magnocellularis from chickens of both sexes that reproduces most features of AIS plasticity in vivo, regarding its effects on characteristics of AIS and cell-type specificity, and revealed that microtubule reorganization via activation of CDK5 underlies plasticity. Treating the culture with a high-K+ medium shortened the AIS and reduced sodium current and membrane excitability, specifically in neurons tuned to high-frequency sound, creating a tonotopic difference in AIS length in the nucleus. Pharmacological analyses revealed that this AIS shortening was driven by multiple Ca2+ pathways and subsequent signaling molecules that converge on CDK5 via the activation of ERK1/2. AIS shortening was suppressed by overexpression of dominant-negative CDK5, whereas it was facilitated by the overexpression of p35, an activator of CDK5. Notably, p35(T138A), a phosphorylation-inactive mutant of p35, did not shorten the AIS. Moreover, microtubule stabilizers occluded AIS shortening during the p35 overexpression, indicating that CDK5/p35 mediated AIS shortening by promoting disassembly of microtubules at distal AIS. This study highlights the importance of microtubule reorganization and regulation of CDK5 activity in structural AIS plasticity and the tuning of AIS characteristics in neurons.SIGNIFICANCE STATEMENT The structural plasticity of AIS has a strong impact on the output of neurons and plays a fundamental role in the physiology and pathology of the brain. However, the mechanisms linking neuronal activity to structural changes in AIS are not well understood. In this study, we prepared an organotypic culture of avian auditory brainstem, reproducing most AIS plasticity features in vivo, and we revealed that activity-dependent AIS shortening occurs through the disassembly of microtubules at distal AIS via activation of CDK5/p35 signals. This study emphasizes the importance of microtubule reorganization and regulation of CDK5 activity in structural AIS plasticity and tonotopic differentiation of AIS structures in the brainstem auditory circuit.
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Vicente-Acosta A, Giménez-Cassina A, Díaz-Nido J, Loria F. The smoothened agonist SAG reduces mitochondrial dysfunction and neurotoxicity of frataxin-deficient astrocytes. J Neuroinflammation 2022; 19:93. [PMID: 35413853 PMCID: PMC9006607 DOI: 10.1186/s12974-022-02442-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 03/24/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Friedreich's ataxia is a rare hereditary neurodegenerative disease caused by decreased levels of the mitochondrial protein frataxin. Similar to other neurodegenerative pathologies, previous studies suggested that astrocytes might contribute to the progression of the disease. To fully understand the mechanisms underlying neurodegeneration in Friedreich's ataxia, we investigated the reactivity status and functioning of cultured human astrocytes after frataxin depletion using an RNA interference-based approach and tested the effect of pharmacologically modulating the SHH pathway as a novel neuroprotective strategy. RESULTS We observed loss of cell viability, mitochondrial alterations, increased autophagy and lipid accumulation in cultured astrocytes upon frataxin depletion. Besides, frataxin-deficient cells show higher expression of several A1-reactivity markers and release of pro-inflammatory cytokines. Interestingly, most of these defects were prevented by chronically treating the cells with the smoothened agonist SAG. Furthermore, in vitro culture of neurons with conditioned medium from frataxin-deficient astrocytes results in a reduction of neuronal survival, neurite length and synapse formation. However, when frataxin-deficient astrocytes were chronically treated with SAG, we did not observe these alterations in neurons. CONCLUSIONS Our results demonstrate that the pharmacological activation of the SHH pathway could be used as a target to modulate astrocyte reactivity and neuron-glia interactions to prevent neurodegeneration in Friedreich's ataxia.
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Affiliation(s)
- Andrés Vicente-Acosta
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Francisco Tomás y Valiente, 7, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain
- Instituto de Investigación Sanitaria Puerta de Hierro, Segovia de Arana, Hospital Universitario Puerta de Hierro, Joaquín Rodrigo 1, Majadahonda, 28222 Madrid, Spain
- Program in Molecular Biosciences, Doctoral School, Universidad Autónoma de Madrid, Madrid, Spain
| | - Alfredo Giménez-Cassina
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Francisco Tomás y Valiente, 7, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain
| | - Javier Díaz-Nido
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Francisco Tomás y Valiente, 7, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain
- Instituto de Investigación Sanitaria Puerta de Hierro, Segovia de Arana, Hospital Universitario Puerta de Hierro, Joaquín Rodrigo 1, Majadahonda, 28222 Madrid, Spain
| | - Frida Loria
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Francisco Tomás y Valiente, 7, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain
- Laboratorio de Apoyo a la Investigación, Hospital Universitario Fundación Alcorcón, Budapest 1, Alcorcón, 28922 Madrid, Spain
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Effect of ACY-1215 on cytoskeletal remodeling and histone acetylation in bovine somatic cell nuclear transfer embryos. Theriogenology 2022; 183:98-107. [DOI: 10.1016/j.theriogenology.2022.02.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 01/10/2022] [Accepted: 02/18/2022] [Indexed: 11/23/2022]
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Zhang W, Ciorraga M, Mendez P, Retana D, Boumedine-Guignon N, Achón B, Russier M, Debanne D, Garrido JJ. Formin Activity and mDia1 Contribute to Maintain Axon Initial Segment Composition and Structure. Mol Neurobiol 2021; 58:6153-6169. [PMID: 34458961 PMCID: PMC8639558 DOI: 10.1007/s12035-021-02531-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/11/2021] [Indexed: 10/29/2022]
Abstract
The axon initial segment (AIS) is essential for maintaining neuronal polarity, modulating protein transport into the axon, and action potential generation. These functions are supported by a distinctive actin and microtubule cytoskeleton that controls axonal trafficking and maintains a high density of voltage-gated ion channels linked by scaffold proteins to the AIS cytoskeleton. However, our knowledge of the mechanisms and proteins involved in AIS cytoskeleton regulation to maintain or modulate AIS structure is limited. In this context, formins play a significant role in the modulation of actin and microtubules. We show that pharmacological inhibition of formins modifies AIS actin and microtubule characteristics in cultured hippocampal neurons, reducing F-actin density and decreasing microtubule acetylation. Moreover, formin inhibition diminishes sodium channels, ankyrinG and βIV-spectrin AIS density, and AIS length, in cultured neurons and brain slices, accompanied by decreased neuronal excitability. We show that genetic downregulation of the mDia1 formin by interference RNAs also decreases AIS protein density and shortens AIS length. The ankyrinG decrease and AIS shortening observed in pharmacologically inhibited neurons and neuron-expressing mDia1 shRNAs were impaired by HDAC6 downregulation or EB1-GFP expression, known to increase microtubule acetylation or stability. However, actin stabilization only partially prevented AIS shortening without affecting AIS protein density loss. These results suggest that mDia1 maintain AIS composition and length contributing to the stability of AIS microtubules.
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Affiliation(s)
- Wei Zhang
- Instituto Cajal, CSIC, 28002 Madrid, Spain
- Present Address: College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | | | | | | | | | | | - Michaël Russier
- UNIS, INSERM, UMR 1072, Aix-Marseille Université, 13015 Marseille, France
| | - Dominique Debanne
- UNIS, INSERM, UMR 1072, Aix-Marseille Université, 13015 Marseille, France
| | - Juan José Garrido
- Instituto Cajal, CSIC, 28002 Madrid, Spain
- Alzheimer’s Disease and Other Degenerative Dementias, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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7
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Abstract
Neuroepigenetics, a new branch of epigenetics, plays an important role in the regulation of gene expression. Neuroepigenetics is associated with holistic neuronal function and helps in formation and maintenance of memory and learning processes. This includes neurodevelopment and neurodegenerative defects in which histone modification enzymes appear to play a crucial role. These modifications, carried out by acetyltransferases and deacetylases, regulate biologic and cellular processes such as apoptosis and autophagy, inflammatory response, mitochondrial dysfunction, cell-cycle progression and oxidative stress. Alterations in acetylation status of histone as well as non-histone substrates lead to transcriptional deregulation. Histone deacetylase decreases acetylation status and causes transcriptional repression of regulatory genes involved in neural plasticity, synaptogenesis, synaptic and neural plasticity, cognition and memory, and neural differentiation. Transcriptional deactivation in the brain results in development of neurodevelopmental and neurodegenerative disorders. Mounting evidence implicates histone deacetylase inhibitors as potential therapeutic targets to combat neurologic disorders. Recent studies have targeted naturally-occurring biomolecules and micro-RNAs to improve cognitive defects and memory. Multi-target drug ligands targeting HDAC have been developed and used in cell-culture and animal-models of neurologic disorders to ameliorate synaptic and cognitive dysfunction. Herein, we focus on the implications of histone deacetylase enzymes in neuropathology, their regulation of brain function and plausible involvement in the pathogenesis of neurologic defects.
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8
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Mazzocchi M, Goulding SR, Wyatt SL, Collins LM, Sullivan AM, O'Keeffe GW. LMK235, a small molecule inhibitor of HDAC4/5, protects dopaminergic neurons against neurotoxin- and α-synuclein-induced degeneration in cellular models of Parkinson's disease. Mol Cell Neurosci 2021; 115:103642. [PMID: 34119632 DOI: 10.1016/j.mcn.2021.103642] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 06/03/2021] [Accepted: 06/05/2021] [Indexed: 01/24/2023] Open
Abstract
Epigenetic modifications in neurodegenerative disease are under investigation for their roles in disease progression. Alterations in acetylation rates of certain Parkinson's disease (PD)-linked genes have been associated with the pathological progression of this disorder. In light of this, and given the lack of disease-modifying therapies for PD, HDAC inhibitors (HDIs) are under consideration as potential pharmacological agents. The neuroprotective effects of pan-HDACs and some class-specific inhibitors have been tested in in vivo and in vitro models of PD, with varying outcomes. Here we used gene co-expression analysis to identify HDACs that are associated with human dopaminergic (DA) neuron development. We identified HDAC3, HDAC5, HDAC6 and HDAC9 as being highly correlated with the DA markers, SLC6A3 and NR4A2. RT-qPCR revealed that mRNA expression of these HDACs exhibited similar temporal profiles during embryonic mouse midbrain DA (mDA) neuron development. We tested the neuroprotective potential of a number of class-specific small molecule HDIs on human SH-SY5Y cells, using neurite growth as a phenotypic readout of neurotrophic action. Neither the class I-specific HDIs, RGFP109 and RGFP966, nor the HDAC6 inhibitor ACY1215, had significant effects on neurite outgrowth. However, the class IIa HDI, LMK235 (a HDAC4/5 inhibitor), significantly increased histone acetylation and neurite outgrowth. We found that LMK235 increased BMP-Smad-dependent transcription in SH-SY5Y cells and that this was required for its neurite growth-promoting effects on SH-SY5Y cells and on DA neurons in primary cultures of embryonic day (E) 14 rat ventral mesencephalon (VM). These effects were also seen in SH-SY5Y cells transfected with HDAC5 siRNA. Furthermore, LMK235 treatment exerted neuroprotective effects against degeneration induced by the DA neurotoxin 1-methyl-4-phenylpyridinium (MPP+), in both SH-SY5Y cells and cultured DA neurons. Treatment with LMK235 was also neuroprotective against axonal degeneration induced by overexpression of wild-type (WT) or A53T mutant α-synuclein in both SH-SY5Y cells and primary cultures of DA neurons. In summary, these data show the neuroprotective potential of the class IIa HDI, LMK235, in cell models of relevance to PD.
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Affiliation(s)
- Martina Mazzocchi
- Department of Anatomy & Neuroscience, University College Cork (UCC), Cork, Ireland
| | - Susan R Goulding
- Department of Anatomy & Neuroscience, University College Cork (UCC), Cork, Ireland
| | - Sean L Wyatt
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Louise M Collins
- Department of Anatomy & Neuroscience, University College Cork (UCC), Cork, Ireland; Department of Physiology, UCC, Cork, Ireland
| | - Aideen M Sullivan
- Department of Anatomy & Neuroscience, University College Cork (UCC), Cork, Ireland; APC Microbiome Ireland, UCC, Cork, Ireland.
| | - Gerard W O'Keeffe
- Department of Anatomy & Neuroscience, University College Cork (UCC), Cork, Ireland; APC Microbiome Ireland, UCC, Cork, Ireland.
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9
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Li X, Saiyin H, Zhou JH, Yu Q, Liang WM. HDAC6 is critical for ketamine-induced impairment of dendritic and spine growth in GABAergic projection neurons. Acta Pharmacol Sin 2021; 42:861-870. [PMID: 32939037 PMCID: PMC8149677 DOI: 10.1038/s41401-020-00521-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/24/2020] [Indexed: 11/09/2022] Open
Abstract
Ketamine is widely used in infants and children for anesthesia; both anesthetic and sub-anesthetic doses of ketamine have been reported to preferentially inhibit the GABAergic neurons. Medium spiny neurons (MSNs), the GABAergic projection neurons in the striatum, are vulnerable to anesthetic exposure in the newborn brain. Growth of dendrites requires a deacetylase to remove acetyl from tubulin in the growth cone to destabilize the tubulin. Histone deacetylase 6 (HDAC6) affects microtubule dynamics, which are involved in neurite elongation. In this study we used a human induced pluripotent stem cells (iPSCs)-derived striatal GABA neuron system to investigate the effects of ketamine on HDAC6 and the morphological development of MSNs. We showed that exposure to ketamine (1-500 μM) decreased dendritic growth, dendrite branches, and dendritic spine density in MSNs in a time- and concentration-dependent manner. We revealed that ketamine treatment concentration-dependently inhibited the expression of HDAC6 or aberrantly translocated HDAC6 into the nucleus. Ketamine inhibition on HDAC6 resulted in α-tubulin hyperacetylation, consequently increasing the stability of microtubules and delaying the dendritic growth of MSNs. Finally, we showed that the effects of a single-dose exposure on MSNs were reversible and lasted for at least 10 days. This study reveals a novel role of HDAC6 as a regulator for ketamine-induced deficits in the morphological development of MSNs and provides an innovative method for prevention and treatment with respect to ketamine clinical applications.
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Affiliation(s)
- Xuan Li
- Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, 200040, China
| | - Hexige Saiyin
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200433, China
| | - Jian-Hua Zhou
- Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, 200040, China
| | - Qiong Yu
- Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, 200040, China.
| | - Wei-Min Liang
- Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, 200040, China.
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10
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Cappelletti G, Calogero AM, Rolando C. Microtubule acetylation: A reading key to neural physiology and degeneration. Neurosci Lett 2021; 755:135900. [PMID: 33878428 DOI: 10.1016/j.neulet.2021.135900] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 04/11/2021] [Accepted: 04/12/2021] [Indexed: 02/02/2023]
Abstract
Neurons are the perfect example of cells where microtubules are essential to achieve an extraordinary degree of morphological and functional complexity. Different tubulin isoforms and associated post-translational modifications are the basis to establish the diversity in biochemical and biophysical properties of microtubules including their stability and the control of intracellular transport. Acetylation is one of the key tubulin modifications and it can influence important structural, mechanical and biological traits of the microtubule network. Here, we present the emerging evidence for the essential role of microtubule acetylation in the control of neuronal and glial function in healthy and degenerative conditions. In particular, we discuss the pathogenic role of tubulin acetylation in neurodegenerative disorders and focus on Parkinson's disease. We also provide a critical analysis about the possibility to target tubulin acetylation as a novel therapeutic intervention for neuroprotective strategies.
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Affiliation(s)
- Graziella Cappelletti
- Department of Biosciences, Università degli Studi di Milano, Milano, Italy; Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Milano, Italy.
| | | | - Chiara Rolando
- Department of Biosciences, Università degli Studi di Milano, Milano, Italy
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11
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Wang M, Du Y, Gao S, Wang Z, Qu P, Gao Y, Wang J, Liu Z, Zhang J, Zhang Y, Qing S, Wang Y. Sperm-borne miR-202 targets SEPT7 and regulates first cleavage of bovine embryos via cytoskeletal remodeling. Development 2021; 148:dev.189670. [PMID: 33472846 DOI: 10.1242/dev.189670] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 01/08/2021] [Indexed: 01/28/2023]
Abstract
In mammals, sperm-borne regulators can be transferred to oocytes during fertilization and have different effects on the formation of pronuclei, the first cleavage of zygotes, the development of preimplantation embryos and even the metabolism of individuals after birth. The regulatory role of sperm microRNAs (miRNAs) in the development of bovine preimplantation embryos has not been reported in detail. By constructing and screening miRNA expression libraries, we found that miR-202 was highly enriched in bovine sperm. As a target gene of miR-202, co-injection of SEPT7 siRNA can partially reverse the accelerated first cleavage of bovine embryos caused by miR-202 inhibitor. In addition, both a miR-202 mimic and SEPT7 siRNA delayed the first cleavage of somatic cell nuclear transfer (SCNT) embryos, suggesting that miR-202-SEPT7 mediates the delay of first cleavage of bovine embryos. By further exploring the relationship between miR-202/SEPT7, HDAC6 and acetylated α-tubulin during embryonic development, we investigated how sperm-borne miR-202 regulates the first cleavage process of bovine embryos by SEPT7 and demonstrate the potential of sperm-borne miRNAs to improve the efficiency of SCNT.
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Affiliation(s)
- Mengyun Wang
- College of Veterinary Medicine, Northwest A&F University, Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Yangling 712100, Shaanxi Province, China.,School of Life Science and Technology, Harbin Institute of Technology, Science Park of Harbin Institute of Technology, Harbin 150000, China
| | - Yue Du
- College of Veterinary Medicine, Northwest A&F University, Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Yangling 712100, Shaanxi Province, China.,Nuffield Division of Clinical Laboratory Sciences, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK
| | - Song Gao
- College of Veterinary Medicine, Northwest A&F University, Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Yangling 712100, Shaanxi Province, China
| | - Zheng Wang
- College of Veterinary Medicine, Northwest A&F University, Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Yangling 712100, Shaanxi Province, China
| | - Pengxiang Qu
- College of Veterinary Medicine, Northwest A&F University, Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Yangling 712100, Shaanxi Province, China
| | - Yang Gao
- College of Veterinary Medicine, Northwest A&F University, Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Yangling 712100, Shaanxi Province, China
| | - Jingyi Wang
- College of Veterinary Medicine, Northwest A&F University, Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Yangling 712100, Shaanxi Province, China
| | - Zhengqi Liu
- College of Veterinary Medicine, Northwest A&F University, Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Yangling 712100, Shaanxi Province, China
| | - Jingcheng Zhang
- College of Veterinary Medicine, Northwest A&F University, Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Yangling 712100, Shaanxi Province, China
| | - Yong Zhang
- College of Veterinary Medicine, Northwest A&F University, Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Yangling 712100, Shaanxi Province, China
| | - Suzhu Qing
- College of Veterinary Medicine, Northwest A&F University, Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Yangling 712100, Shaanxi Province, China
| | - Yongsheng Wang
- College of Veterinary Medicine, Northwest A&F University, Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Yangling 712100, Shaanxi Province, China
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12
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Moreno-Lorite J, Pérez-Luz S, Katsu-Jiménez Y, Oberdoerfer D, Díaz-Nido J. DNA repair pathways are altered in neural cell models of frataxin deficiency. Mol Cell Neurosci 2021; 111:103587. [PMID: 33418083 DOI: 10.1016/j.mcn.2020.103587] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 12/20/2020] [Accepted: 12/26/2020] [Indexed: 12/14/2022] Open
Abstract
Friedreich's ataxia (FRDA) is a hereditary and predominantly neurodegenerative disease caused by a deficiency of the protein frataxin (FXN). As part of the overall efforts to understand the molecular basis of neurodegeneration in FRDA, a new human neural cell line with doxycycline-induced FXN knockdown was established. This cell line, hereafter referred to as iFKD-SY, is derived from the human neuroblastoma SH-SY5Y and retains the ability to differentiate into mature neuron-like cells. In both proliferating and differentiated iFKD-SY cells, the induction of FXN deficiency is accompanied by increases in oxidative stress and DNA damage, reduced aconitase enzyme activity, higher levels of p53 and p21, activation of caspase-3, and subsequent apoptosis. More interestingly, FXN-deficient iFKD-SY cells exhibit an important transcriptional deregulation in many of the genes implicated in DNA repair pathways. The levels of some crucial proteins involved in DNA repair appear notably diminished. Furthermore, similar changes are found in two additional neural cell models of FXN deficit: primary cultures of FXN-deficient mouse neurons and human olfactory mucosa stem cells obtained from biopsies of FRDA patients. These results suggest that the deficiency of FXN leads to a down-regulation of DNA repair pathways that synergizes with oxidative stress to provoke DNA damage, which may be involved in the pathogenesis of FRDA. Thus, a failure in DNA repair may be considered a shared common molecular mechanism contributing to neurodegeneration in a number of hereditary ataxias including FRDA.
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Affiliation(s)
- Jara Moreno-Lorite
- Departamento Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain; Instituto de Investigación Sanitaria Puerta de Hierro-Majadahonda (IDIPHIM), Spain
| | - Sara Pérez-Luz
- Departamento Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain; Instituto de Investigación Sanitaria Puerta de Hierro-Majadahonda (IDIPHIM), Spain; Molecular Genetics Unit, Institute of Rare Diseases Research, Institute of Health Carlos III (ISCIII), Ctra. Majadahonda-Pozuelo Km2.200, 28220 Madrid, Spain.
| | - Yurika Katsu-Jiménez
- Departamento Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain; Instituto de Investigación Sanitaria Puerta de Hierro-Majadahonda (IDIPHIM), Spain
| | - Daniel Oberdoerfer
- Departamento Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain; Instituto de Investigación Sanitaria Puerta de Hierro-Majadahonda (IDIPHIM), Spain
| | - Javier Díaz-Nido
- Departamento Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain; Instituto de Investigación Sanitaria Puerta de Hierro-Majadahonda (IDIPHIM), Spain
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13
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Liu C, Liu J, Liu C, Zhou Q, Zhou Y, Zhang B, Saijilafu. The intrinsic axon regenerative properties of mature neurons after injury. Acta Biochim Biophys Sin (Shanghai) 2021; 53:1-9. [PMID: 33258872 DOI: 10.1093/abbs/gmaa148] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Indexed: 01/07/2023] Open
Abstract
Thousands of nerve injuries occur in the world each year. Axon regeneration is a very critical process for the restoration of the injured nervous system's function. However, the precise molecular mechanism or signaling cascades that control axon regeneration are not clearly understood, especially in mammals. Therefore, there is almost no ideal treatment method to repair the nervous system's injury until now. Mammalian axonal regeneration requires multiple signaling pathways to coordinately regulate gene expression in soma and assembly of the cytoskeleton protein in the growth cone. A better understanding of their molecular mechanisms, such as axon regeneration regulatory signaling cascades, will be helpful in developing new treatment strategies for promoting axon regeneration. In this review, we mainly focus on describing these regeneration-associated signaling cascades, which regulate axon regeneration.
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Affiliation(s)
- Chunfeng Liu
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Jinlian Liu
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Chaoqun Liu
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Qing Zhou
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Yaodong Zhou
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Boyin Zhang
- Orthopedics Surgery Department, China-Japan Union Hospital of Jilin University, Changchun 130033, China
| | - Saijilafu
- Department of Orthopaedics, The First Affiliated Hospital, Orthopaedic Institute, Soochow University, Suzhou 215007, China
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14
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Wilson C, Cáceres A. New insights on epigenetic mechanisms supporting axonal development: histone marks and miRNAs. FEBS J 2020; 288:6353-6364. [PMID: 33332753 DOI: 10.1111/febs.15673] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/21/2020] [Accepted: 12/15/2020] [Indexed: 11/27/2022]
Abstract
Mechanisms supporting axon growth and the establishment of neuronal polarity have remained largely disconnected from their genetic and epigenetic fundamentals. Recently, post-transcriptional modifications of histones involved in chromatin folding and transcription, and microRNAs controlling translation have emerged as regulators of axonal specification, growth, and guidance. In this article, we review novel evidence supporting the concept that epigenetic mechanisms work at both transcriptional and post-transcriptional levels to shape axons. We also discuss the role of splicing on axonal growth, as one of the most (if not the most) powerful post-transcriptional mechanism to diversify genetic information. Overall, we think exploring the gap between epigenetics and axonal growth raises new questions and perspectives to the development of axons in physiological and pathological contexts.
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Affiliation(s)
- Carlos Wilson
- Centro de Investigación en Medicina Traslacional "Severo R Amuchástegui" (CIMETSA), Instituto Universitario Ciencias Biomédicas Córdoba (IUCBC), Córdoba, Argentina.,Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC-CONICET-UNC), Córdoba, Argentina.,Universidad Nacional de Córdoba (UNC), Argentina
| | - Alfredo Cáceres
- Centro de Investigación en Medicina Traslacional "Severo R Amuchástegui" (CIMETSA), Instituto Universitario Ciencias Biomédicas Córdoba (IUCBC), Córdoba, Argentina
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15
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Ageta-Ishihara N, Kinoshita M. Developmental and postdevelopmental roles of septins in the brain. Neurosci Res 2020; 170:6-12. [PMID: 33159992 DOI: 10.1016/j.neures.2020.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 08/21/2020] [Accepted: 08/23/2020] [Indexed: 11/25/2022]
Abstract
Morphogenetic processes during brain development and postdevelopmental remodeling of neural architecture depend on the exquisite interplay between the microtubule- and actin-based cytoskeletal systems. Accumulation of evidence indicates cooperative roles of another cytoskeletal system composed of the septin family. Here we overview experimental findings on mammalian septins and their hypothetical roles in the proliferation of neural progenitor cells, neurite development, synapse formation and regulations. The diverse, mostly unexpected phenotypes obtained from gain- and loss-of-function mutants point to unknown molecular network to be elucidated, which may underlie pathogenetic processes of infectious diseases and neuropsychiatric disorders in humans.
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Affiliation(s)
- Natsumi Ageta-Ishihara
- Division of Biological Science, Nagoya University Graduate School of Science, Furo, Chikusa, Nagoya 464-8602, Japan.
| | - Makoto Kinoshita
- Division of Biological Science, Nagoya University Graduate School of Science, Furo, Chikusa, Nagoya 464-8602, Japan.
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16
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Trzeciakiewicz H, Ajit D, Tseng JH, Chen Y, Ajit A, Tabassum Z, Lobrovich R, Peterson C, Riddick NV, Itano MS, Tripathy A, Moy SS, Lee VMY, Trojanowski JQ, Irwin DJ, Cohen TJ. An HDAC6-dependent surveillance mechanism suppresses tau-mediated neurodegeneration and cognitive decline. Nat Commun 2020; 11:5522. [PMID: 33139698 PMCID: PMC7606452 DOI: 10.1038/s41467-020-19317-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 10/08/2020] [Indexed: 01/15/2023] Open
Abstract
Tauopathies including Alzheimer’s disease (AD) are marked by the accumulation of aberrantly modified tau proteins. Acetylated tau, in particular, has recently been implicated in neurodegeneration and cognitive decline. HDAC6 reversibly regulates tau acetylation, but its role in tauopathy progression remains unclear. Here, we identified an HDAC6-chaperone complex that targets aberrantly modified tau. HDAC6 not only deacetylates tau but also suppresses tau hyperphosphorylation within the microtubule-binding region. In neurons and human AD brain, HDAC6 becomes co-aggregated within focal tau swellings and human AD neuritic plaques. Using mass spectrometry, we identify a novel HDAC6-regulated tau acetylation site as a disease specific marker for 3R/4R and 3R tauopathies, supporting uniquely modified tau species in different neurodegenerative disorders. Tau transgenic mice lacking HDAC6 show reduced survival characterized by accelerated tau pathology and cognitive decline. We propose that a HDAC6-dependent surveillance mechanism suppresses toxic tau accumulation, which may protect against the progression of AD and related tauopathies. HDAC6 is a tau deacetylase and acetylation of tau inhibits its function and promotes aggregation. Here the authors show that HDAC6 protects against tau accumulation in a mouse model of tauopathy.
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Affiliation(s)
- Hanna Trzeciakiewicz
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, 27599-7260, USA
| | - Deepa Ajit
- Department of Neurology, UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC, 27599-7250, USA
| | - Jui-Heng Tseng
- Department of Neurology, UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC, 27599-7250, USA
| | - Youjun Chen
- Department of Neurology, UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC, 27599-7250, USA
| | - Aditi Ajit
- Department of Neurology, UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC, 27599-7250, USA
| | - Zarin Tabassum
- Department of Neurology, UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC, 27599-7250, USA
| | - Rebecca Lobrovich
- Penn Digital Neuropathology Laboratory, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-4283, USA
| | - Claire Peterson
- Penn Digital Neuropathology Laboratory, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-4283, USA
| | - Natallia V Riddick
- Division of Comparative Medicine, University of North Carolina, Chapel Hill, NC, 27599-7146, USA
| | - Michelle S Itano
- Department of Cell Biology and Physiology, Carolina Institute for Developmental Disabilities, UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC, 27599-7250, USA
| | - Ashutosh Tripathy
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, 27599-7260, USA
| | - Sheryl S Moy
- Department of Psychiatry, Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC, 27599-7146, USA
| | - Virginia M Y Lee
- Department of Pathology & Laboratory Medicine, Center for Neurodegenerative Disease Research (CNDR), Institute on Aging, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-4283, USA
| | - John Q Trojanowski
- Department of Pathology & Laboratory Medicine, Center for Neurodegenerative Disease Research (CNDR), Institute on Aging, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-4283, USA
| | - David J Irwin
- Penn Digital Neuropathology Laboratory, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-4283, USA
| | - Todd J Cohen
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, 27599-7260, USA. .,Department of Neurology, UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC, 27599-7250, USA.
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17
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Rossaert E, Van Den Bosch L. HDAC6 inhibitors: Translating genetic and molecular insights into a therapy for axonal CMT. Brain Res 2020; 1733:146692. [PMID: 32006555 DOI: 10.1016/j.brainres.2020.146692] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/24/2020] [Accepted: 01/27/2020] [Indexed: 12/25/2022]
Abstract
Histone deacetylase 6 (HDAC6) plays a central role in various processes that are key for neuronal survival. In this review, we summarize the current evidence related to disease pathways in the axonal form of Charcot-Marie-Tooth disease (CMT) and highlight the role of HDAC6 in these pathways. We hypothesize that HDAC6 might in fact actively contribute to the pathogenesis of certain forms of axonal CMT. HDAC6 plays a deacetylase activity-dependent, negative role in axonal transport and axonal regeneration, which are both processes implicated in axonal CMT. On the other hand, HDAC6 coordinates a protective response during elimination of toxic misfolded proteins, but this is mostly mediated independent of its deacetylase activity. The current mechanistic insights on these functions of HDAC6 in axonal CMT, along with the selective druggability against its deacetylase activity, make the targeting of HDAC6 particularly attractive. We elaborate on the preclinical studies that demonstrated beneficial effects of HDAC6 inhibitors in axonal CMT models and outline possible modes of action. Overall, this overview ultimately provides a rationale for the use of small-molecule HDAC6 inhibitors as a therapeutic strategy for this devastating disease.
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Affiliation(s)
- Elisabeth Rossaert
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), Leuven, Belgium; VIB - Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Ludo Van Den Bosch
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), Leuven, Belgium; VIB - Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.
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18
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D'Mello SR. Regulation of Central Nervous System Development by Class I Histone Deacetylases. Dev Neurosci 2020; 41:149-165. [PMID: 31982872 PMCID: PMC7263453 DOI: 10.1159/000505535] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 12/18/2019] [Indexed: 12/15/2022] Open
Abstract
Neurodevelopment is a highly complex process composed of several carefully regulated events starting from the proliferation of neuroepithelial cells and culminating with and refining of neural networks and synaptic transmission. Improper regulation of any of these neurodevelopmental events often results in severe brain dysfunction. Accumulating evidence indicates that epigenetic modifications of chromatin play a key role in neurodevelopmental regulation. Among these modifications are histone acetylation and deacetylation, which control access of transcription factors to DNA, thereby regulating gene transcription. Histone deacetylation, which restricts access of transcription factor repressing gene transcription, involves the action of members of a family of 18 enzymes, the histone deacetylases (HDAC), which are subdivided in 4 subgroups. This review focuses on the Group 1 HDACs - HDAC 1, 2, 3, and 8. Although much of the evidence for HDAC involvement in neurodevelopment has come from the use of pharmacological inhibitors, because these agents are generally nonselective with regard to their effects on individual members of the HDAC family, this review is limited to evidence garnered from the use of molecular genetic approaches. Our review describes that Class I HDACs play essential roles in all phases of neurodevelopment. Modulation of the activity of individual HDACs could be an important therapeutic approach for neurodevelopmental and psychiatric disorders.
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Affiliation(s)
- Santosh R D'Mello
- Department of Biological Sciences, Southern Methodist University, Dallas, Texas, USA,
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19
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Zhang W, Bonadiman A, Ciorraga M, Benitez MJ, Garrido JJ. P2Y1 Purinergic Receptor Modulate Axon Initial Segment Initial Development. Front Cell Neurosci 2019; 13:152. [PMID: 31068791 PMCID: PMC6491782 DOI: 10.3389/fncel.2019.00152] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/08/2019] [Indexed: 11/22/2022] Open
Abstract
Morphological and functional polarization of neurons depends on the generation and maintenance of the axon initial segment (AIS). This axonal domain maintains axonal properties but is also the place where the action potential (AP) is generated. All these functions require the AIS, a complex structure that is not fully understood. An integrated structure of voltage-gated ion channels, specific cytoskeleton architecture, as well as, scaffold proteins contributes to these functions. Among them, ankyrinG plays a crucial role to maintain ion channels and membrane proteins. However, it is still elusive how the AIS performs its complex structural and functional regulation. Recent studies reveal that AIS is dynamically regulated in molecular composition, length and location in response to neuronal activity. Some mechanisms acting on AIS plasticity have been uncovered recently, including Ca2+, calpain or calmodulin-mediated modulation, as well as post-translational modifications of cytoskeleton proteins and actin-associated proteins. Neurons are able to respond to different kind of physiological and pathological stimuli from development to maturity by adapting their AIS composition, position and length. This raises the question of which are the neuronal receptors that contribute to the modulation of AIS plasticity. Previous studies have shown that purinergic receptor P2X7 activation is detrimental to AIS maintenance. During initial axonal elongation, P2X7 is coordinated with P2Y1, another purinergic receptor that is essential for proper axon elongation. In this study, we focus on the role of P2Y1 receptor on AIS development and maintenance. Our results show that P2Y1 receptor activity and expression are necessary during AIS initial development, while has no role once AIS maturity is achieved. P2Y1 inhibition or suppression results in a decrease in ankyrinG, βIV-spectrin and voltage-gated sodium channels accumulation that can be rescued by actin stabilization or the modulation of actin-binding proteins at the AIS. Moreover, P2X7 or calpain inhibition also rescues ankyrinG decrease. Hence, a dynamic balance of P2Y1 and P2X7 receptors expression and function during AIS assembly and maturation may represent a fine regulatory mechanism in response to physiological or pathological extracellular purines concentration.
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Affiliation(s)
- Wei Zhang
- Spanish National Research Council (CSIC), Department of Molecular, Cellular and Developmental Neurobiology, Instituto Cajal, Madrid, Spain
| | - Angela Bonadiman
- Spanish National Research Council (CSIC), Department of Molecular, Cellular and Developmental Neurobiology, Instituto Cajal, Madrid, Spain
| | - María Ciorraga
- Spanish National Research Council (CSIC), Department of Molecular, Cellular and Developmental Neurobiology, Instituto Cajal, Madrid, Spain
| | - María José Benitez
- Spanish National Research Council (CSIC), Department of Molecular, Cellular and Developmental Neurobiology, Instituto Cajal, Madrid, Spain.,Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan José Garrido
- Spanish National Research Council (CSIC), Department of Molecular, Cellular and Developmental Neurobiology, Instituto Cajal, Madrid, Spain
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20
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Maturation Dynamics of the Axon Initial Segment (AIS) of Newborn Dentate Granule Cells in Young Adult C57BL/6J Mice. J Neurosci 2019; 39:1605-1620. [PMID: 30651327 DOI: 10.1523/jneurosci.2253-18.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 12/27/2018] [Accepted: 01/04/2019] [Indexed: 01/07/2023] Open
Abstract
Newborn dentate granule cells (DGCs) are generated in the hippocampal dentate gyrus (DG) of rodents through a process called adult hippocampal neurogenesis, which is subjected to tight intrinsic and extrinsic regulation. The use of retroviruses encoding fluorescent proteins has allowed the characterization of the maturation dynamics of newborn DGCs, including their morphological development and the establishment and maturation of their afferent and efferent synaptic connections. However, the study of a crucial cellular compartment of these cells, namely, the axon initial segment (AIS), has remained unexplored to date. The AIS is not only the site of action potential initiation, but it also has a unique molecular identity that makes it one of the master regulators of neural plasticity and excitability. Here we examined the dynamics of AIS formation in newborn DGCs of young female adult C57BL/6J mice in vivo Our data reveal notable changes in AIS length and thickness throughout cell maturation under physiological conditions and show that the most remarkable structural changes coincide with periods of intense morphological and functional remodeling. Moreover, we demonstrate that AIS development can be modulated extrinsically by both neuroprotective (environmental enrichment) and detrimental (lipopolysaccharide from Escherichia coli) stimuli.SIGNIFICANCE STATEMENT The hippocampal dentate gyrus (DG) of rodents generates newborn dentate granule cells (DGCs) throughout life. This process, named adult hippocampal neurogenesis, confers a unique degree of plasticity to the hippocampal circuit, and it is crucial for learning and memory. Here we studied, for the first time, the formation of a key cellular compartment of newborn DGCs, namely, the axon initial segment (AIS) in vivo Our data reveal remarkable AIS structural remodeling throughout the maturation of these cells under physiological conditions. Moreover, AIS development can be modulated extrinsically by both neuroprotective (environmental enrichment) and detrimental (lipopolysaccharide from Escherichia coli) stimuli.
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21
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Schartner E, Sabbir MG, Saleh A, Silva RV, Roy Chowdhury S, Smith DR, Fernyhough P. High glucose concentration suppresses a SIRT2 regulated pathway that enhances neurite outgrowth in cultured adult sensory neurons. Exp Neurol 2018; 309:134-147. [PMID: 30102915 DOI: 10.1016/j.expneurol.2018.08.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 08/05/2018] [Accepted: 08/09/2018] [Indexed: 12/21/2022]
Abstract
In peripheral nerve under hyperglycemic conditions high flux of d-glucose through the polyol pathway drives an aberrant redox state contributing to neurodegeneration in diabetic sensorimotor polyneuropathy (DSPN). Sirtuins, including SIRT2, detect the redox state via the NAD+/NADH ratio to regulate mitochondrial function via, in part, AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α). In adult dorsal root ganglia (DRG) sensory neurons mitochondrial dysfunction has been proposed as an etiological factor in dying-back neuropathy in diabetes. We tested the hypothesis that a high concentration of d-glucose depleted SIRT2 expression via enhancement of polyol pathway activity. We posited that this would lead to impaired mitochondrial function and suppression of neurite outgrowth in cultured sensory neurons. The use of dominant negative mutants or neurons from SIRT2 knockout (KO) mice to block SIRT2 signaling revealed that neurons derived from control or type 1 diabetic rodents required SIRT2 for optimal neurite outgrowth. Over-expression of WT-SIRT2 elevated neurite outgrowth in normal and diabetic cultures. SIRT2 protein isoforms 2.1 and 2.2 were reduced by 20-30% in DRG of type 1 diabetic mice (p < .05). After 72 h exposure to high d-glucose (25 mM vs 5 mM) cultured sensory neurons showed a significant 2-fold (p < .05) decrease in SIRT2 expression, P-AMPK, levels of respiratory Complexes II/III and respiratory capacity. DRG neurons expressed aldose reductase and the aforementioned deficits were prevented by treatment with aldose reductase inhibitors (lidorestat or sorbinil) or sorbitol dehydrogenase inhibitor (SDI-158). In cultures derived from type 1 diabetic rats treatment with SDI-158 elevated expression of SIRT2, P-AMPK/PGC-1α and neurite outgrowth (p < .05). SIRT2 KO neurons exhibited deficits in the LKB-1/AMPK/PGC-1α pathway and mitochondrial function. In cultured neurons the SIRT2 pathway enhances axonal outgrowth and this signaling axis encompassing activation of AMPK/PGC-1α is impaired in DSPN, in part, due to enhanced polyol pathway activity caused by hyperglycemia.
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Affiliation(s)
- Emily Schartner
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada; Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, Canada
| | - Mohammad Golam Sabbir
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada
| | - Ali Saleh
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada
| | - Rafaela Vieira Silva
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, Canada; Faculty of Pharmacy, Federal University of Rio de Janeiro - UFRJ, Rio de Janeiro, Brazil
| | - Subir Roy Chowdhury
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada
| | - Darrell R Smith
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada
| | - Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada; Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, Canada.
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22
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Hinton SD. The role of pseudophosphatases as signaling regulators. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:167-174. [PMID: 30077638 DOI: 10.1016/j.bbamcr.2018.07.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/23/2018] [Accepted: 07/27/2018] [Indexed: 12/13/2022]
Abstract
Pseudophosphatases are atypical members of the protein tyrosine phosphatase superfamily. Mutations within their catalytic signature motif render them catalytically inactive. Despite this lack of catalytic function, pseudophosphatases have been implicated in various diseases such as Charcot Marie-Tooth disorder, cancer, metabolic disorder, and obesity. Moreover, they have roles in various signaling networks such as spermatogenesis, apoptosis, stress response, tumorigenesis, and neurite differentiation. This review highlights the roles of pseudophosphatases as essential regulators in signaling cascades, providing insight into the function of these catalytically inactive enzymes.
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Affiliation(s)
- Shantá D Hinton
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA, USA.
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23
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Landucci E, Brindisi M, Bianciardi L, Catania LM, Daga S, Croci S, Frullanti E, Fallerini C, Butini S, Brogi S, Furini S, Melani R, Molinaro A, Lorenzetti FC, Imperatore V, Amabile S, Mariani J, Mari F, Ariani F, Pizzorusso T, Pinto AM, Vaccarino FM, Renieri A, Campiani G, Meloni I. iPSC-derived neurons profiling reveals GABAergic circuit disruption and acetylated α-tubulin defect which improves after iHDAC6 treatment in Rett syndrome. Exp Cell Res 2018; 368:225-235. [PMID: 29730163 DOI: 10.1016/j.yexcr.2018.05.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 04/30/2018] [Accepted: 05/02/2018] [Indexed: 12/22/2022]
Abstract
Mutations in MECP2 gene have been identified in more than 95% of patients with classic Rett syndrome, one of the most common neurodevelopmental disorders in females. Taking advantage of the breakthrough technology of genetic reprogramming, we investigated transcriptome changes in neurons differentiated from induced Pluripotent Stem Cells (iPSCs) derived from patients with different mutations. Profiling by RNA-seq in terminally differentiated neurons revealed a prominent GABAergic circuit disruption along with a perturbation of cytoskeleton dynamics. In particular, in mutated neurons we identified a significant decrease of acetylated α-tubulin which can be reverted by treatment with selective inhibitors of HDAC6, the main α-tubulin deacetylase. These findings contribute to shed light on Rett pathogenic mechanisms and provide hints for the treatment of Rett-associated epileptic behavior as well as for the definition of new therapeutic strategies for Rett syndrome.
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Affiliation(s)
- Elisa Landucci
- Medical Genetics, University of Siena, Strada delle Scotte 4, 53100, Siena, Italy
| | - Margherita Brindisi
- NatSynDrugs, Department of Biotechnology, Chemistry and Pharmacy, DoE 2018-2022 University of Siena, via Aldo Moro 2, 53100 Siena, Italy
| | - Laura Bianciardi
- Medical Genetics, University of Siena, Strada delle Scotte 4, 53100, Siena, Italy
| | - Lorenza M Catania
- Medical Genetics, University of Siena, Strada delle Scotte 4, 53100, Siena, Italy
| | - Sergio Daga
- Medical Genetics, University of Siena, Strada delle Scotte 4, 53100, Siena, Italy
| | - Susanna Croci
- Medical Genetics, University of Siena, Strada delle Scotte 4, 53100, Siena, Italy
| | - Elisa Frullanti
- Medical Genetics, University of Siena, Strada delle Scotte 4, 53100, Siena, Italy
| | - Chiara Fallerini
- Medical Genetics, University of Siena, Strada delle Scotte 4, 53100, Siena, Italy
| | - Stefania Butini
- NatSynDrugs, Department of Biotechnology, Chemistry and Pharmacy, DoE 2018-2022 University of Siena, via Aldo Moro 2, 53100 Siena, Italy
| | - Simone Brogi
- NatSynDrugs, Department of Biotechnology, Chemistry and Pharmacy, DoE 2018-2022 University of Siena, via Aldo Moro 2, 53100 Siena, Italy
| | - Simone Furini
- Department of Medical Biotechnologies, University of Siena, Strada delle Scotte 4, 53100 Siena, Italy
| | - Riccardo Melani
- Institute of Neuroscience, National Research Council (CNR), Via Giuseppe Moruzzi, 1, 56124 Pisa, Italy
| | - Angelo Molinaro
- Institute of Neuroscience, National Research Council (CNR), Via Giuseppe Moruzzi, 1, 56124 Pisa, Italy; Department of Neuroscience, Psychology, Drug Research and Child Health NEUROFARBA, University of Florence, Viale Gaetano Pieraccini, 6, 50139 Florence, Italy
| | | | - Valentina Imperatore
- Medical Genetics, University of Siena, Strada delle Scotte 4, 53100, Siena, Italy
| | - Sonia Amabile
- Medical Genetics, University of Siena, Strada delle Scotte 4, 53100, Siena, Italy
| | - Jessica Mariani
- Yale University, Child Study Center, 230 South Frontage Rd, New Haven, CT 06520, United States
| | - Francesca Mari
- Medical Genetics, University of Siena, Strada delle Scotte 4, 53100, Siena, Italy; Genetica Medica, Azienda Ospedaliera Universitaria Senese, Viale Mario Bracci 2, 53100 Siena, Italy
| | - Francesca Ariani
- Medical Genetics, University of Siena, Strada delle Scotte 4, 53100, Siena, Italy; Genetica Medica, Azienda Ospedaliera Universitaria Senese, Viale Mario Bracci 2, 53100 Siena, Italy
| | - Tommaso Pizzorusso
- Institute of Neuroscience, National Research Council (CNR), Via Giuseppe Moruzzi, 1, 56124 Pisa, Italy; Department of Neuroscience, Psychology, Drug Research and Child Health NEUROFARBA, University of Florence, Viale Gaetano Pieraccini, 6, 50139 Florence, Italy; BIO@SNS lab, Scuola Normale Superiore, Piazza dei Cavalieri, 7, 56126 Pisa, Italy
| | - Anna Maria Pinto
- Medical Genetics, University of Siena, Strada delle Scotte 4, 53100, Siena, Italy; Genetica Medica, Azienda Ospedaliera Universitaria Senese, Viale Mario Bracci 2, 53100 Siena, Italy
| | - Flora M Vaccarino
- Yale University, Child Study Center, 230 South Frontage Rd, New Haven, CT 06520, United States
| | - Alessandra Renieri
- Medical Genetics, University of Siena, Strada delle Scotte 4, 53100, Siena, Italy; Genetica Medica, Azienda Ospedaliera Universitaria Senese, Viale Mario Bracci 2, 53100 Siena, Italy.
| | - Giuseppe Campiani
- NatSynDrugs, Department of Biotechnology, Chemistry and Pharmacy, DoE 2018-2022 University of Siena, via Aldo Moro 2, 53100 Siena, Italy.
| | - Ilaria Meloni
- Medical Genetics, University of Siena, Strada delle Scotte 4, 53100, Siena, Italy
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24
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Berger SL, Leo-Macias A, Yuen S, Khatri L, Pfennig S, Zhang Y, Agullo-Pascual E, Caillol G, Zhu MS, Rothenberg E, Melendez-Vasquez CV, Delmar M, Leterrier C, Salzer JL. Localized Myosin II Activity Regulates Assembly and Plasticity of the Axon Initial Segment. Neuron 2018; 97:555-570.e6. [PMID: 29395909 PMCID: PMC5805619 DOI: 10.1016/j.neuron.2017.12.039] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 08/24/2017] [Accepted: 12/22/2017] [Indexed: 01/08/2023]
Abstract
The axon initial segment (AIS) is the site of action potential generation and a locus of activity-dependent homeostatic plasticity. A multimeric complex of sodium channels, linked via a cytoskeletal scaffold of ankyrin G and beta IV spectrin to submembranous actin rings, mediates these functions. The mechanisms that specify the AIS complex to the proximal axon and underlie its plasticity remain poorly understood. Here we show phosphorylated myosin light chain (pMLC), an activator of contractile myosin II, is highly enriched in the assembling and mature AIS, where it associates with actin rings. MLC phosphorylation and myosin II contractile activity are required for AIS assembly, and they regulate the distribution of AIS components along the axon. pMLC is rapidly lost during depolarization, destabilizing actin and thereby providing a mechanism for activity-dependent structural plasticity of the AIS. Together, these results identify pMLC/myosin II activity as a common link between AIS assembly and plasticity.
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Affiliation(s)
- Stephen L Berger
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | | | - Stephanie Yuen
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Latika Khatri
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Sylvia Pfennig
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | - Yanqing Zhang
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA
| | | | - Ghislaine Caillol
- Aix Marseille Université, CNRS, INP UMR7051, 13344 Cedex 15, Marseille, France
| | - Min-Sheng Zhu
- Model Animal Research Center and MOE Key Laboratory of Model Animal and Disease Study, Nanjing University, Nanjing 210061, China
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA
| | - Carmen V Melendez-Vasquez
- Department of Biological Sciences, Hunter College, New York, NY 10065, USA; Department of Molecular, Cellular, and Developmental Biology, The Graduate Center, The City University of New York, NY 10016, USA
| | - Mario Delmar
- Division of Cardiology, NYU School of Medicine, New York, NY 10016, USA
| | | | - James L Salzer
- Neuroscience Institute and Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY 10016, USA.
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25
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The Axon Initial Segment: An Updated Viewpoint. J Neurosci 2018; 38:2135-2145. [PMID: 29378864 DOI: 10.1523/jneurosci.1922-17.2018] [Citation(s) in RCA: 164] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 01/20/2018] [Accepted: 01/25/2018] [Indexed: 12/20/2022] Open
Abstract
At the base of axons sits a unique compartment called the axon initial segment (AIS). The AIS generates and shapes the action potential before it is propagated along the axon. Neuronal excitability thus depends crucially on the AIS composition and position, and these adapt to developmental and physiological conditions. The AIS also demarcates the boundary between the somatodendritic and axonal compartments. Recent studies have brought insights into the molecular architecture of the AIS and how it regulates protein trafficking. This Viewpoints article summarizes current knowledge about the AIS and highlights future challenges in understanding this key actor of neuronal physiology.
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26
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Jenkins BV, Saunders HAJ, Record HL, Johnson-Schlitz DM, Wildonger J. Effects of mutating α-tubulin lysine 40 on sensory dendrite development. J Cell Sci 2017; 130:4120-4131. [PMID: 29122984 PMCID: PMC5769580 DOI: 10.1242/jcs.210203] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/06/2017] [Indexed: 12/28/2022] Open
Abstract
Microtubules are essential for neuronal structure and function. Axonal and dendritic microtubules are enriched in post-translational modifications that impact microtubule dynamics, transport and microtubule-associated proteins. Acetylation of α-tubulin lysine 40 (K40) is a prominent and conserved modification of neuronal microtubules. However, the cellular role of microtubule acetylation remains controversial. To resolve how microtubule acetylation might affect neuronal morphogenesis, we mutated endogenous α-tubulin in vivo using a new Drosophila strain that facilitates the rapid knock-in of designer αTub84B alleles (the predominant α-tubulin-encoding gene in flies). Leveraging our new strain, we found that microtubule acetylation, as well as polyglutamylation and (de)tyrosination, is not essential for survival. However, we found that dendrite branch refinement in sensory neurons relies on α-tubulin K40. Mutagenesis of K40 reveals moderate yet significant changes in dendritic lysosome transport, microtubule polymerization and Futsch protein distribution in dendrites but not in axons. Our studies point to an unappreciated role for α-tubulin K40 and acetylation in dendrite morphogenesis. While our results are consistent with the idea that acetylation tunes microtubule function within neurons, they also suggest there may be an acetylation-independent requirement for α-tubulin K40. This article has an associated First Person interview with the first author of the paper. Highlighted Article: Neurons are enriched in post-translationally modified microtubules. Targeted mutagenesis of endogenous α-tubulin in flies reveals that dendrite branch refinement is altered by acetylation-blocking mutations.
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Affiliation(s)
- Brian V Jenkins
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Harriet A J Saunders
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA.,Integrated Program in Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Helena L Record
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA
| | | | - Jill Wildonger
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA
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27
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28
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Nucleocytoplasmic Shuttling of Histone Deacetylase 9 Controls Activity-Dependent Thalamocortical Axon Branching. Sci Rep 2017; 7:6024. [PMID: 28729685 PMCID: PMC5519695 DOI: 10.1038/s41598-017-06243-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 06/13/2017] [Indexed: 01/12/2023] Open
Abstract
During development, thalamocortical (TC) axons form branches in an activity-dependent fashion. Here we investigated how neuronal activity is converted to molecular signals, focusing on an epigenetic mechanism involving histone deacetylases (HDACs). Immunohistochemistry demonstrated that HDAC9 was translocated from the nucleus to the cytoplasm of thalamic cells during the first postnatal week in rats. In organotypic co-cultures of the thalamus and cortex, fluorescent protein-tagged HDAC9 also exhibited nuclueocytoplasmic translocation in thalamic cells during culturing, which was reversed by tetrodotoxin treatment. Transfection with a mutant HDAC9 that interferes with the translocation markedly decreased TC axon branching in the culture. Similarly, TC axon branching was significantly decreased by the mutant HDAC9 gene transfer in vivo. However, axonal branching was restored by disrupting the interaction between HDAC9 and myocyte-specific enhancer factor 2 (MEF2). Taken together, the present results demonstrate that the nucleocytoplasmic translocation of HDAC9 plays a critical role in activity-dependent TC axon branching by affecting transcriptional regulation and downstream signaling pathways.
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29
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Lin S, Sterling NA, Junker IP, Helm CT, Smith GM. Effects of αTAT1 and HDAC5 on axonal regeneration in adult neurons. PLoS One 2017; 12:e0177496. [PMID: 28505206 PMCID: PMC5432171 DOI: 10.1371/journal.pone.0177496] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 04/27/2017] [Indexed: 12/28/2022] Open
Abstract
The role of posttranslational modifications in axonal injury and regeneration has been widely studied but there has been little consensus over the mechanism by which each modification affects adult axonal growth. Acetylation is known to play an important role in a variety of neuronal functions and its homeostasis is controlled by two enzyme families: the Histone Deacetylases (HDACs) and Histone Acetyl Transferases (HATs). Recent studies show that HDAC5 deacetylates microtubules in the axonal cytoplasm as part of an injury-induced regeneration response, but little is known about how acetylation of microtubules plays a role. Alpha-tubulin acetyl transferase (αTAT1) is a microtubule specific acetyl transferase that binds to microtubules and directly affects microtubule stability in cells. We hypothesize that increasing tubulin acetylation may play an important role in increasing the rate of axonal growth. In this study, we infected cultured adult DRG neurons with αTAT1 and αTAT1-D157N, a catalytically inactive mutant, and HDAC5, using lentiviruses. We found that αTAT1 significantly increases tubulin acetylation in 293T cells and DRG neurons but αTAT1-D157N does not. Furthermore, in neurons infected with αTAT1, a significant increase in acetylated tubulin was detected towards the distal portion of the axon but this increase was not detected in neurons infected with αTAT1-D157N. However, we found a significant increase in axon lengths of DRG neurons after αTAT1 and αTAT1-D157N infection, but no effect on axon lengths after infection with HDAC5. Our results suggest that while αTAT1 may play a role in axon growth in vitro, the increase is not directly due to acetylation of axonal microtubules. Our results also show that HDAC5 overexpression in the axonal cytoplasm does not play a crucial role in axonal regeneration of cultured DRG neurons. We expressed these genes in DRG neurons in adult rats and performed a sciatic nerve crush. We found that axons did not regenerate any better when infected with any of the constructs compared with control animals. Thus, while αTAT1 may be important for axonal growth in vitro, neither αTAT1 nor HDAC5 had an effect in vivo on the regeneration of sciatic nerves.
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Affiliation(s)
- Shen Lin
- Center for Neural Repair and Rehabilitation, Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| | - Noelle A. Sterling
- Center for Neural Repair and Rehabilitation, Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Ian P. Junker
- Center for Neural Repair and Rehabilitation, Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Courtney T. Helm
- Center for Neural Repair and Rehabilitation, Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - George M. Smith
- Center for Neural Repair and Rehabilitation, Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
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30
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Ho Y, Zhou L, Tam KC, Too H. Enhanced non-viral gene delivery by coordinated endosomal release and inhibition of β-tubulin deactylase. Nucleic Acids Res 2017; 45:e38. [PMID: 27899629 PMCID: PMC5389648 DOI: 10.1093/nar/gkw1143] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/04/2016] [Accepted: 11/04/2016] [Indexed: 12/20/2022] Open
Abstract
Efficient non-viral gene delivery is highly desirable but often unattainable with some cell-types. We report here that non-viral DNA polyplexes can efficiently transfect differentiated neuronal and stem cells. Polyplex transfection centrifugation protocols was enhanced by including a simultaneous treatment with a DOPE/CHEMS lipid suspension and a microtubule inhibitor, Tubastatin A. Lipoplex transfection protocols were not improved by this treatment. This mechanism of action was unravelled by systematically identifying and rationally mitigating barriers limiting high transfection efficiency, allowing unexpected improvements in the transfection of mesenchymal stem cells (MSC), primary neuron and several hard-to-transfect cell types beyond what are currently achievable using cationic polymers. The optimized formulation and method achieved high transfection efficiency with no adverse effects on cell viability, cell proliferation or differentiation. High efficiency modification of MSC for cytokine overexpression, efficient generation of dopaminergic neuron using neural stem cells and enhanced genome editing with CRISPR-Cas9 were demonstrated. In summary, this study described a cost-effective method for efficient, rapid and scalable workflow for ex vivo gene delivery using a myriad of nucleic acids including plasmid DNA, mRNA, siRNA and shRNA.
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Affiliation(s)
- Yoon Khei Ho
- Bioprocessing Technology Institute, Agency for Science, Technology, and Research (A*STAR), 138668 Singapore
| | - Li Han Zhou
- MiRXES, 10 Biopolis Road, Chromos 03-01, 138670 Singapore
| | - Kam C. Tam
- Department of Chemical Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Heng Phon Too
- Bioprocessing Technology Institute, Agency for Science, Technology, and Research (A*STAR), 138668 Singapore
- Department of Biochemistry, National University of Singapore, 119260 Singapore
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31
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Satake T, Yamashita K, Hayashi K, Miyatake S, Tamura-Nakano M, Doi H, Furuta Y, Shioi G, Miura E, Takeo YH, Yoshida K, Yahikozawa H, Matsumoto N, Yuzaki M, Suzuki A. MTCL1 plays an essential role in maintaining Purkinje neuron axon initial segment. EMBO J 2017; 36:1227-1242. [PMID: 28283581 DOI: 10.15252/embj.201695630] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 02/07/2017] [Accepted: 02/10/2017] [Indexed: 11/09/2022] Open
Abstract
The axon initial segment (AIS) is a specialized domain essential for neuronal function, the formation of which begins with localization of an ankyrin-G (AnkG) scaffold. However, the mechanism directing and maintaining AnkG localization is largely unknown. In this study, we demonstrate that in vivo knockdown of microtubule cross-linking factor 1 (MTCL1) in cerebellar Purkinje cells causes loss of axonal polarity coupled with AnkG mislocalization. MTCL1 lacking MT-stabilizing activity failed to restore these defects, and stable MT bundles spanning the AIS were disorganized in knockdown cells. Interestingly, during early postnatal development, colocalization of MTCL1 with these stable MT bundles was observed prominently in the axon hillock and proximal axon. These results indicate that MTCL1-mediated formation of stable MT bundles is crucial for maintenance of AnkG localization. We also demonstrate that Mtcl1 gene disruption results in abnormal motor coordination with Purkinje cell degeneration, and provide evidence suggesting possible involvement of MTCL1 dysfunction in the pathogenesis of spinocerebellar ataxia.
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Affiliation(s)
- Tomoko Satake
- Molecular Cellular Biology Laboratory, Yokohama City University Graduate School of Medical Life Science, Tsurumi-ku Yokohama, Japan
| | - Kazunari Yamashita
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, Kanazawa-ku Yokohama, Japan
| | - Kenji Hayashi
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, Kanazawa-ku Yokohama, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medical Science, Kanazawa-ku Yokohama, Japan
| | - Miwa Tamura-Nakano
- Communal Laboratory, Research Institute, National Center for Global Health and Medicine, Toyama Shinjuku-ku Tokyo, Japan
| | - Hiroshi Doi
- Department of Neurology, Yokohama City University Graduate School of Medical Science, Kanazawa-ku Yokohama, Japan
| | - Yasuhide Furuta
- Animal Resource Development Unit, RIKEN Center for Life Science Technologies, Chuou-ku Kobe, Japan.,Genetic Engineering Team, RIKEN Center for Life Science Technologies, Chuou-ku Kobe, Japan
| | - Go Shioi
- Genetic Engineering Team, RIKEN Center for Life Science Technologies, Chuou-ku Kobe, Japan
| | - Eriko Miura
- Department of Physiology, School of Medicine, Keio University, Shinjuku-ku Tokyo, Japan
| | - Yukari H Takeo
- Department of Physiology, School of Medicine, Keio University, Shinjuku-ku Tokyo, Japan
| | - Kunihiro Yoshida
- Division of Neurogenetics, Department of Brain Disease Research, Shinshu University School of Medicine, Asahi Matsumoto, Japan
| | | | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medical Science, Kanazawa-ku Yokohama, Japan
| | - Michisuke Yuzaki
- Department of Physiology, School of Medicine, Keio University, Shinjuku-ku Tokyo, Japan
| | - Atsushi Suzuki
- Molecular Cellular Biology Laboratory, Yokohama City University Graduate School of Medical Life Science, Tsurumi-ku Yokohama, Japan
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32
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Tapia M, Dominguez A, Zhang W, Del Puerto A, Ciorraga M, Benitez MJ, Guaza C, Garrido JJ. Cannabinoid Receptors Modulate Neuronal Morphology and AnkyrinG Density at the Axon Initial Segment. Front Cell Neurosci 2017; 11:5. [PMID: 28179879 PMCID: PMC5263140 DOI: 10.3389/fncel.2017.00005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 01/10/2017] [Indexed: 12/27/2022] Open
Abstract
Neuronal polarization underlies the ability of neurons to integrate and transmit information. This process begins early in development with axon outgrowth, followed by dendritic growth and subsequent maturation. In between these two steps, the axon initial segment (AIS), a subcellular domain crucial for generating action potentials (APs) and maintaining the morphological and functional polarization, starts to develop. However, the cellular/molecular mechanisms and receptors involved in AIS initial development and maturation are mostly unknown. In this study, we have focused on the role of the type-1 cannabinoid receptor (CB1R), a highly abundant G-protein coupled receptor (GPCR) in the nervous system largely involved in different phases of neuronal development and differentiation. Although CB1R activity modulation has been related to changes in axons or dendrites, its possible role as a modulator of AIS development has not been yet explored. Here we analyzed the potential role of CB1R on neuronal morphology and AIS development using pharmacological and RNA interference approaches in cultured hippocampal neurons. CB1R inhibition, at a very early developmental stage, has no effect on axonal growth, yet CB1R activation can promote it. By contrast, subsequent dendritic growth is impaired by CB1R inhibition, which also reduces ankyrinG density at the AIS. Moreover, our data show a significant correlation between early dendritic growth and ankyrinG density. However, CB1R inhibition in later developmental stages after dendrites are formed only reduces ankyrinG accumulation at the AIS. In conclusion, our data suggest that neuronal CB1R basal activity plays a role in initial development of dendrites and indirectly in AIS proteins accumulation. Based on the lack of CB1R expression at the AIS, we hypothesize that CB1R mediated modulation of dendritic arbor size during early development indirectly determines the accumulation of ankyrinG and AIS development. Further studies will be necessary to determine which CB1R-dependent mechanisms can coordinate these two domains, and what may be the impact of these early developmental changes once neurons mature and are embedded in a functional brain network.
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Affiliation(s)
- Mónica Tapia
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC) Madrid, Spain
| | - Ana Dominguez
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC) Madrid, Spain
| | - Wei Zhang
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC) Madrid, Spain
| | - Ana Del Puerto
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC) Madrid, Spain
| | - María Ciorraga
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC) Madrid, Spain
| | - María José Benitez
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC)Madrid, Spain; Department of Quimica Fisica Aplicada, Universidad Autónoma de MadridMadrid, Spain
| | - Carmen Guaza
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC) Madrid, Spain
| | - Juan José Garrido
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC) Madrid, Spain
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33
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Jeong SG, Cho GW. The tubulin deacetylase sirtuin-2 regulates neuronal differentiation through the ERK/CREB signaling pathway. Biochem Biophys Res Commun 2017; 482:182-187. [DOI: 10.1016/j.bbrc.2016.11.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 11/07/2016] [Indexed: 12/14/2022]
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34
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Cebotaru L, Liu Q, Yanda MK, Boinot C, Outeda P, Huso DL, Watnick T, Guggino WB, Cebotaru V. Inhibition of histone deacetylase 6 activity reduces cyst growth in polycystic kidney disease. Kidney Int 2016; 90:90-9. [PMID: 27165822 DOI: 10.1016/j.kint.2016.01.026] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 01/18/2016] [Accepted: 01/28/2016] [Indexed: 12/27/2022]
Abstract
Abnormal proliferation of cyst-lining epithelium and increased intracystic fluid secretion via the cystic fibrosis transmembrane conductance regulator (CFTR) are thought to contribute to cyst growth in autosomal dominant polycystic kidney disease (ADPKD). Histone deacetylase 6 (HDAC6) expression and activity are increased in certain cancers, neurodegenerative diseases, and in Pkd1-mutant renal epithelial cells. Inhibition of HDAC6 activity with specific inhibitors slows cancer growth. Here we studied the effect of tubacin, a specific HDAC6 inhibitor, on cyst growth in polycystic kidney disease. Treatment with tubacin prevented cyst formation in MDCK cells, an in vitro model of cystogenesis. Cyclic AMP stimulates cell proliferation and activates intracystic CFTR-mediated chloride secretion in ADPKD. Treatment with tubacin downregulated cyclic AMP levels, inhibited cell proliferation, and inhibited cyclic AMP-activated CFTR chloride currents in MDCK cells. We also found that tubacin reduced cyst growth by inhibiting proliferation of cyst-lining epithelial cells, downregulated cyclic AMP levels, and improved renal function in a Pkd1-conditional mouse model of ADPKD. Thus, HDAC6 could play a role in cyst formation and could serve as a potential therapeutic target in ADPKD.
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Affiliation(s)
- Liudmila Cebotaru
- Division of Gastroenterology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Qiangni Liu
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Murali K Yanda
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Clement Boinot
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Patricia Outeda
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - David L Huso
- Department of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Terry Watnick
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - William B Guggino
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Valeriu Cebotaru
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA.
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35
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36
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Jagirdar R, Drexel M, Bukovac A, Tasan RO, Sperk G. Expression of class II histone deacetylases in two mouse models of temporal lobe epilepsy. J Neurochem 2015; 136:717-730. [PMID: 26603269 PMCID: PMC4738395 DOI: 10.1111/jnc.13440] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 11/10/2015] [Indexed: 11/04/2022]
Abstract
Epigenetic mechanisms like altered histone acetylation may have a crucial role in epileptogenesis. In two mouse models of temporal lobe epilepsy, we investigated changes in the expression of class II histone deacetylases (HDAC), a group of signal transducers that shuttle between nucleus and cytoplasm. Intrahippocampal injection of kainic acid (KA) induced a status epilepticus, development of spontaneous seizures (after 3 days), and finally chronic epilepsy and granule cell dispersion. Expression of class II HDAC mRNAs was investigated at different time intervals after KA injection in the granule cell layers and in sectors CA1 and CA3 contralateral to the site of KA injection lacking neurodegeneration. Increased expression of HDAC5 and 9 mRNAs coincided with pronounced granule cell dispersion in the KA‐injected hippocampus at late intervals (14–28 days after KA) and equally affected both HDAC9 splice variants. In contrast, in the pilocarpine model (showing no granule cell dispersion), we observed decreases in the expression of HDAC5 and 9 at the same time intervals. Beyond this, striking similarities between both temporal lobe epilepsy models such as fast decreases in HDAC7 and 10 mRNAs during the acute status epilepticus were observed, notably also in the contralateral hippocampus not affected by neurodegeneration. The particular patterns of HDAC mRNA expression suggest a role in epileptogenesis and granule cell dispersion. Reduced expression of HDACs may result in increased expression of pro‐ and anticonvulsive proteins. On the other hand, export of HDACs from the nucleus into the cytoplasm could allow for deacetylation of cytoplasmatic proteins involved in axonal and dendritic remodeling, like granule cell dispersion. HDAC 5 and HDAC 9 expression is highly increased in granule cells of the KA‐injected hippocampus and parallels granule cell dispersion. Both HDACs are thought to be targeted to the cytoplasm and to act there by deacetylating cytoplasmatic (e.g. cytosceleton‐related) proteins.
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Affiliation(s)
- Rohan Jagirdar
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Meinrad Drexel
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Anneliese Bukovac
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Ramon O Tasan
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Günther Sperk
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
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37
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Namba T, Funahashi Y, Nakamuta S, Xu C, Takano T, Kaibuchi K. Extracellular and Intracellular Signaling for Neuronal Polarity. Physiol Rev 2015; 95:995-1024. [PMID: 26133936 DOI: 10.1152/physrev.00025.2014] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Neurons are one of the highly polarized cells in the body. One of the fundamental issues in neuroscience is how neurons establish their polarity; therefore, this issue fascinates many scientists. Cultured neurons are useful tools for analyzing the mechanisms of neuronal polarization, and indeed, most of the molecules important in their polarization were identified using culture systems. However, we now know that the process of neuronal polarization in vivo differs in some respects from that in cultured neurons. One of the major differences is their surrounding microenvironment; neurons in vivo can be influenced by extrinsic factors from the microenvironment. Therefore, a major question remains: How are neurons polarized in vivo? Here, we begin by reviewing the process of neuronal polarization in culture conditions and in vivo. We also survey the molecular mechanisms underlying neuronal polarization. Finally, we introduce the theoretical basis of neuronal polarization and the possible involvement of neuronal polarity in disease and traumatic brain injury.
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Affiliation(s)
- Takashi Namba
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuhiro Funahashi
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shinichi Nakamuta
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Chundi Xu
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tetsuya Takano
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Kozo Kaibuchi
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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38
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Affiliation(s)
- Fanny Ng
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University Health System, Medical Drive, 117597, Singapore
| | - Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University Health System, Medical Drive, 117597, Singapore ; Graduate School for Integrative Sciences and Engineering, National University of Singapore, Medical Drive, 117597, Singapore
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39
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Abstract
Maintenance of neuronal polarity and regulation of cytoskeletal dynamics are vital during development and to uphold synaptic activity in neuronal networks. Here we show that soluble β-amyloid (Aβ) disrupts actin and microtubule (MT) dynamics via activation of RhoA and inhibition of histone deacetylase 6 (HDAC6) in cultured hippocampal neurons. The contact of Aβ with the extracellular membrane promotes RhoA activation, leading to growth cone collapse and neurite retraction, which might be responsible for hampered neuronal pathfinding and migration in Alzheimer's disease (AD). The inhibition of HDAC6 by Aβ increases the level of heterodimeric acetylated tubulin and acetylated tau, both of which have been found altered in AD. We also find that the loss of HDAC6 activity perturbs the integrity of axon initial segment (AIS), resulting in mislocalization of ankyrin G and increased MT instability in the AIS concomitant with loss of polarized localization of tau and impairment of action potential firing.
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40
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Loría F, Díaz-Nido J. Frataxin knockdown in human astrocytes triggers cell death and the release of factors that cause neuronal toxicity. Neurobiol Dis 2015; 76:1-12. [PMID: 25554687 DOI: 10.1016/j.nbd.2014.12.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 11/15/2014] [Accepted: 12/21/2014] [Indexed: 01/27/2023] Open
Abstract
Friedreich's ataxia (FA) is a recessive, predominantly neurodegenerative disorder caused in most cases by mutations in the first intron of the frataxin (FXN) gene. This mutation drives the expansion of a homozygous GAA repeat that results in decreased levels of FXN transcription and frataxin protein. Frataxin (Fxn) is a ubiquitous mitochondrial protein involved in iron-sulfur cluster biogenesis, and a decrease in the levels of this protein is responsible for the symptoms observed in the disease. Although the pathological manifestations of FA are mainly observed in neurons of both the central and peripheral nervous system, it is not clear if changes in non-neuronal cells may also contribute to the pathogenesis of FA, as recently suggested for other neurodegenerative disorders. Therefore, the aims of this study were to generate and characterize a cell model of Fxn deficiency in human astrocytes (HAs) and to evaluate the possible involvement of non-cell autonomous processes in FA. To knockdown frataxin in vitro, we transduced HAs with a specific shRNA lentivirus (shRNA37), which produced a decrease in both frataxin mRNA and protein expression, along with mitochondrial superoxide production, and signs of p53-mediated cell cycle arrest and apoptotic cell death. To test for non-cell autonomous interactions we cultured wild-type mouse neurons in the presence of frataxin-deficient astrocyte conditioned medium, which provoked a delay in the maturation of these neurons, a decrease in neurite length and enhanced cell death. Our findings confirm a detrimental effect of frataxin silencing, not only for astrocytes, but also for neuron-glia interactions, underlining the need to take into account the role of non-cell autonomous processes in FA.
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Affiliation(s)
- Frida Loría
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | - Javier Díaz-Nido
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain; Departamento de Biología Molecular, Universidad Autónoma de Madrid, Madrid, Spain; Center for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain.
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41
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Lin S, Nazif K, Smith A, Baas PW, Smith GM. Histone acetylation inhibitors promote axon growth in adult dorsal root ganglia neurons. J Neurosci Res 2015; 93:1215-28. [PMID: 25702820 DOI: 10.1002/jnr.23573] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 01/13/2015] [Accepted: 01/26/2015] [Indexed: 12/24/2022]
Abstract
Intrinsic mechanisms that guide damaged axons to regenerate following spinal cord injury remain poorly understood. Manipulation of posttranslational modifications of key proteins in mature neurons could reinvigorate growth machinery after injury. One such modification is acetylation, a reversible process controlled by two enzyme families, the histone deacetylases (HDACs) and the histone acetyl transferases (HATs), acting in opposition. Whereas acetylated histones in the nucleus are associated with upregulation of growth-promoting genes, deacetylated tubulin in the axoplasm is associated with more labile microtubules, conducive to axon growth. This study investigates the effects of HAT and HDAC inhibitors on cultured adult dorsal root ganglia (DRG) neurons and shows that inhibition of HATs by anacardic acid or CPTH2 improves axon outgrowth, whereas inhibition of HDACs by TSA or tubacin inhibits axon growth. Anacardic acid increased the number of axons able to cross an inhibitory chondroitin sulfate proteoglycan border. Histone acetylation but not tubulin acetylation level was affected by HAT inhibitors, whereas tubulin acetylation levels were increased in the presence of the HDAC inhibitor tubacin. Although the microtubule-stabilizing drug taxol did not have an effect on the lengths of DRG axons, nocodazole decreased axon lengths. Determining the mechanistic basis will require future studies, but this study shows that inhibitors of HAT can augment axon growth in adult DRG neurons, with the potential of aiding axon growth over inhibitory substrates produced by the glial scar.
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Affiliation(s)
- Shen Lin
- Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University, Philadelphia, Pennsylvania
| | - Kutaiba Nazif
- Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University, Philadelphia, Pennsylvania
| | - Alexander Smith
- Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University, Philadelphia, Pennsylvania
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - George M Smith
- Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University, Philadelphia, Pennsylvania
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42
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Kaul N, Soppina V, Verhey KJ. Effects of α-tubulin K40 acetylation and detyrosination on kinesin-1 motility in a purified system. Biophys J 2015; 106:2636-43. [PMID: 24940781 DOI: 10.1016/j.bpj.2014.05.008] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 05/07/2014] [Accepted: 05/08/2014] [Indexed: 11/28/2022] Open
Abstract
Long-range transport in cells is achieved primarily through motor-based transport along a network of microtubule tracks. Targeted transport by kinesin motors can be correlated with posttranslational modifications (PTMs) of the tubulin subunits in specific microtubules. To directly examine the influence of specific PTMs on kinesin-1 motility, we generated tubulin subunits that were either enriched in or lacking acetylation of α-tubulin lysine 40 (K40) or detyrosination of the α-tubulin C-terminal tail. We show that K40 acetylation does not result in significant changes in kinesin-1's landing rate or motility parameters (velocity and run length) across experimental conditions. In contrast, detyrosination causes a moderate increase in kinesin-1's landing rate. The fact that the effects of detyrosination are dampened by prior K40 acetylation indicates that the combination of PTMs may be an important aspect of the functional output of microtubule heterogeneity. Importantly, our results indicate that the moderate influences that single PTMs have on kinesin-1 in vitro do not explain the strong correlation between specific PTMs and kinesin-1 transport in cells. Thus, additional mechanisms for regulating kinesin-1 transport in cells must be explored in future work.
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Affiliation(s)
- Neha Kaul
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan.
| | - Virupakshi Soppina
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan
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43
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Tang BL. Class II HDACs and neuronal regeneration. J Cell Biochem 2015; 115:1225-33. [PMID: 24604703 DOI: 10.1002/jcb.24802] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 01/16/2014] [Indexed: 02/03/2023]
Abstract
The vastly more superior regenerative capacity of the axons of peripheral nerves over central nervous system (CNS) neurons has been partly attributed to the former's intrinsic capacity to initiate and sustain the functionality of a new growth cone. Growth cone generation involves a myriad of processes that centers around the organization of microtubule bundles. Histone deacetylases (HDACs) modulate a wide range of key neuronal processes such as neural progenitor differentiation, learning and memory, neuronal death, and degeneration. HDAC inhibitors have been shown to be beneficial in attenuating neuronal death and promoting neurite outgrowth and axonal regeneration. Recent advances have provided insights on how manipulating HDAC activities, particularly the type II HDACs 5 and 6, which deacetylate tubulin, may benefit axonal regeneration. These advances are discussed herein.
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Affiliation(s)
- Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University Health System, Singapore, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Medical Drive, Singapore, 117597, Singapore
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44
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Didonna A, Opal P. The promise and perils of HDAC inhibitors in neurodegeneration. Ann Clin Transl Neurol 2014; 2:79-101. [PMID: 25642438 PMCID: PMC4301678 DOI: 10.1002/acn3.147] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 10/22/2014] [Accepted: 10/24/2014] [Indexed: 12/13/2022] Open
Abstract
Histone deacetylases (HDACs) represent emerging therapeutic targets in the context of neurodegeneration. Indeed, pharmacologic inhibition of HDACs activity in the nervous system has shown beneficial effects in several preclinical models of neurological disorders. However, the translation of such therapeutic approach to clinics has been only marginally successful, mainly due to our still limited knowledge about HDACs physiological role particularly in neurons. Here, we review the potential benefits along with the risks of targeting HDACs in light of what we currently know about HDAC activity in the brain.
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Affiliation(s)
- Alessandro Didonna
- Department of Neurology, University of California San Francisco San Francisco, California, 94158
| | - Puneet Opal
- Davee Department of Neurology, Northwestern University Feinberg School of Medicine Chicago, Illinois, 60611 ; Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine Chicago, Illinois, 60611
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45
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Histone deacetylase 6 regulates cytotoxic α-synuclein accumulation through induction of the heat shock response. Neurobiol Aging 2014; 35:2316-28. [DOI: 10.1016/j.neurobiolaging.2014.04.029] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 04/10/2014] [Accepted: 04/27/2014] [Indexed: 12/18/2022]
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46
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Regulatory mechanisms underlying the differential growth of dendrites and axons. Neurosci Bull 2014; 30:557-68. [PMID: 25001617 DOI: 10.1007/s12264-014-1447-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 04/10/2014] [Indexed: 01/06/2023] Open
Abstract
A typical neuron is comprised of an information input compartment, or the dendrites, and an output compartment, known as the axon. These two compartments are the structural basis for functional neural circuits. However, little is known about how dendritic and axonal growth are differentially regulated. Recent studies have uncovered two distinct types of regulatory mechanisms that differentiate dendritic and axonal growth: dedicated mechanisms and bimodal mechanisms. Dedicated mechanisms regulate either dendritespecific or axon-specific growth; in contrast, bimodal mechanisms direct dendritic and axonal development in opposite manners. Here, we review the dedicated and bimodal regulators identified by recent Drosophila and mammalian studies. The knowledge of these underlying molecular mechanisms not only expands our understanding about how neural circuits are wired, but also provides insights that will aid in the rational design of therapies for neurological diseases.
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47
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Grunseich C, Zukosky K, Kats IR, Ghosh L, Harmison GG, Bott LC, Rinaldi C, Chen KL, Chen G, Boehm M, Fischbeck KH. Stem cell-derived motor neurons from spinal and bulbar muscular atrophy patients. Neurobiol Dis 2014; 70:12-20. [PMID: 24925468 DOI: 10.1016/j.nbd.2014.05.038] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/23/2014] [Accepted: 05/30/2014] [Indexed: 11/26/2022] Open
Abstract
Spinal and bulbar muscular atrophy (SBMA, Kennedy's disease) is a motor neuron disease caused by polyglutamine repeat expansion in the androgen receptor. Although degeneration occurs in the spinal cord and muscle, the exact mechanism is not clear. Induced pluripotent stem cells from spinal and bulbar muscular atrophy patients provide a useful model for understanding the disease mechanism and designing effective therapy. Stem cells were generated from six patients and compared to control lines from three healthy individuals. Motor neurons from four patients were differentiated from stem cells and characterized to understand disease-relevant phenotypes. Stem cells created from patient fibroblasts express less androgen receptor than control cells, but show androgen-dependent stabilization and nuclear translocation. The expanded repeat in several stem cell clones was unstable, with either expansion or contraction. Patient stem cell clones produced a similar number of motor neurons compared to controls, with or without androgen treatment. The stem cell-derived motor neurons had immunoreactivity for HB9, Isl1, ChAT, and SMI-32, and those with the largest repeat expansions were found to have increased acetylated α-tubulin and reduced HDAC6. Reduced HDAC6 was also found in motor neuron cultures from two other patients with shorter repeats. Evaluation of stably transfected mouse cells and SBMA spinal cord showed similar changes in acetylated α-tubulin and HDAC6. Perinuclear lysosomal enrichment, an HDAC6 dependent process, was disrupted in motor neurons from two patients with the longest repeats. SBMA stem cells present new insights into the disease, and the observations of reduced androgen receptor levels, repeat instability, and reduced HDAC6 provide avenues for further investigation of the disease mechanism and development of effective therapy.
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Affiliation(s)
- Christopher Grunseich
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, 2A-1000 Building 35, 35 Convent Drive, NIH, Bethesda, MD 20892, USA.
| | - Kristen Zukosky
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, 2A-1000 Building 35, 35 Convent Drive, NIH, Bethesda, MD 20892, USA.
| | - Ilona R Kats
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, 2A-1000 Building 35, 35 Convent Drive, NIH, Bethesda, MD 20892, USA.
| | - Laboni Ghosh
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, 2A-1000 Building 35, 35 Convent Drive, NIH, Bethesda, MD 20892, USA.
| | - George G Harmison
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, 2A-1000 Building 35, 35 Convent Drive, NIH, Bethesda, MD 20892, USA.
| | - Laura C Bott
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, 2A-1000 Building 35, 35 Convent Drive, NIH, Bethesda, MD 20892, USA; Department of Cell and Molecular Biology, Karolinska Institute, Solnavagen 1, 17177 Solna, Sweden.
| | - Carlo Rinaldi
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, 2A-1000 Building 35, 35 Convent Drive, NIH, Bethesda, MD 20892, USA.
| | - Ke-lian Chen
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, 2A-1000 Building 35, 35 Convent Drive, NIH, Bethesda, MD 20892, USA.
| | - Guibin Chen
- National Heart, Lung and Blood Institute, Bld 10-CRC Rm 5-3132, 10 Center Dr., NIH, Bethesda, MD 20892, USA.
| | - Manfred Boehm
- National Heart, Lung and Blood Institute, Bld 10-CRC Rm 5-3132, 10 Center Dr., NIH, Bethesda, MD 20892, USA.
| | - Kenneth H Fischbeck
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, 2A-1000 Building 35, 35 Convent Drive, NIH, Bethesda, MD 20892, USA.
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48
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Ageta-Ishihara N, Miyata T, Ohshima C, Watanabe M, Sato Y, Hamamura Y, Higashiyama T, Mazitschek R, Bito H, Kinoshita M. Septins promote dendrite and axon development by negatively regulating microtubule stability via HDAC6-mediated deacetylation. Nat Commun 2014; 4:2532. [PMID: 24113571 PMCID: PMC3826633 DOI: 10.1038/ncomms3532] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 09/02/2013] [Indexed: 11/11/2022] Open
Abstract
Neurite growth requires two guanine nucleotide-binding protein polymers of tubulins and septins. However, whether and how those cytoskeletal systems are coordinated was unknown. Here we show that the acute knockdown or knockout of the pivotal septin subunit SEPT7 from cerebrocortical neurons impairs their interhemispheric and cerebrospinal axon projections and dendritogenesis in perinatal mice, when the microtubules are severely hyperacetylated. The resulting hyperstabilization and growth retardation of microtubules are demonstrated in vitro. The phenotypic similarity between SEPT7 depletion and the pharmacological inhibition of α-tubulin deacetylase HDAC6 reveals that HDAC6 requires SEPT7 not for its enzymatic activity, but to associate with acetylated α-tubulin. These and other findings indicate that septins provide a physical scaffold for HDAC6 to achieve efficient microtubule deacetylation, thereby negatively regulating microtubule stability to an optimal level for neuritogenesis. Our findings shed light on the mechanisms underlying the HDAC6-mediated coupling of the two ubiquitous cytoskeletal systems during neural development. Septins are a family of heteropolymerizing GTP/GDP-binding proteins and are implicated in neuritogenesis in nematodes. Ageta-Ishihara et al. show that septins also facilitate this process in the developing mouse brain as scaffolds that coordinate HDAC6-mediated deacetylation of microtubules.
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Affiliation(s)
- Natsumi Ageta-Ishihara
- Division of Biological Sciences, Nagoya University Graduate School of Science, Nagoya 464-8602, Japan
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49
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Yoshimura T, Rasband MN. Axon initial segments: diverse and dynamic neuronal compartments. Curr Opin Neurobiol 2014; 27:96-102. [PMID: 24705243 DOI: 10.1016/j.conb.2014.03.004] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 02/25/2014] [Accepted: 03/09/2014] [Indexed: 01/29/2023]
Abstract
The axon initial segment (AIS) is a structurally and molecularly unique neuronal compartment of the proximal axon that functions as both a physiological and physical bridge between the somatodendritic and axonal domains. The AIS has two main functions: to initiate action potentials and to maintain neuronal polarity. The cytoskeletal scaffold ankyrinG is responsible for these functions and clusters ion channels at the AIS. Recent studies reveal how the AIS forms and remarkable diversity in its structure, function, and composition that may be modulated by neuronal activity and posttranslational modifications of AIS proteins. Furthermore, AIS proteins have been implicated in a variety of human diseases. Here, we discuss these findings and what they teach us about the dynamic AIS.
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Affiliation(s)
- Takeshi Yoshimura
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
| | - Matthew N Rasband
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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50
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No Pasaran! Role of the axon initial segment in the regulation of protein transport and the maintenance of axonal identity. Semin Cell Dev Biol 2014; 27:44-51. [DOI: 10.1016/j.semcdb.2013.11.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 10/29/2013] [Accepted: 11/05/2013] [Indexed: 11/19/2022]
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