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Zhong G, Fang Z, Sun T, Ying M, Wang A, Chen Y, Wang H, Ma C, Wang C, Ge R, Liu G, Guo Y. Ubiquitin ligase RFWD2 promotes dendritic spine and synapse formation by activating the ERK/PEA3/c-Jun pathway in rat cerebral cortical neurons. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167319. [PMID: 38909848 DOI: 10.1016/j.bbadis.2024.167319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 06/12/2024] [Accepted: 06/17/2024] [Indexed: 06/25/2024]
Abstract
The regulation of protein degradation through the ubiquitin-proteasome system is essential for normal brain development, axon growth, synaptic growth and plasticity. The E3 ubiquitin ligase RFWD2 plays a key role in the onset and development of neurological diseases, including the pathogenesis of Alzheimer's disease (AD), but the mechanisms controlling the homeostasis of neuronal synaptic proteins are still poorly understood. Here, we showed that the expression level of RFWD2 gradually decreased with the age of the rats and was negatively correlated with the development of cerebral cortical neurons and dendrites in vivo. RFWD2 was shown to localize to presynaptic terminals and some postsynaptic sides of both excitatory synapses and inhibitory synapses via colocalization with neuronal synaptic proteins (SYN, PSD95, Vglut1 and GAD67). Overexpression of RFWD2 promoted dendrite development and dendritic spine formation and markedly decreased the expression of synaptophysin and PSD95 by reducing the expression of ETV1, ETV4, ETV5 and c-JUN in vitro. Furthermore, the whole-cell membrane slice clamp results showed that RFWD2 overexpression resulted in greater membrane capacitance in neuronal cells, inadequate cell repolarization, and a longer time course for neurons to emit action potentials with decreased excitability. RFWD2 regulates dendritic development and plasticity, dendritic spine formation and synaptic function in rat cerebral cortex neurons by activating the ERK/PEA3/c-Jun pathway via a posttranslational regulatory mechanism and can be used as an efficient treatment target for neurological diseases.
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Affiliation(s)
- Guangshang Zhong
- School of Laboratory Medicine, Bengbu Medical University, Bengbu 233000, Anhui, China; School of Life Sciences, Bengbu Medical University, Bengbu 233000, Anhui, China
| | - Zhuling Fang
- School of Laboratory Medicine, Bengbu Medical University, Bengbu 233000, Anhui, China
| | - Tingting Sun
- School of Life Sciences, Bengbu Medical University, Bengbu 233000, Anhui, China
| | - Mengjiao Ying
- School of Life Sciences, Bengbu Medical University, Bengbu 233000, Anhui, China
| | - Ao Wang
- School of Laboratory Medicine, Bengbu Medical University, Bengbu 233000, Anhui, China
| | - Ying Chen
- School of Life Sciences, Bengbu Medical University, Bengbu 233000, Anhui, China
| | - Haojie Wang
- School of Clinical Medicine, Bengbu Medical University, Bengbu 233000, Anhui, China
| | - Caiyun Ma
- School of Life Sciences, Bengbu Medical University, Bengbu 233000, Anhui, China
| | - Chunjing Wang
- School of Life Sciences, Bengbu Medical University, Bengbu 233000, Anhui, China
| | - Rongjing Ge
- School of Clinical Medicine, Bengbu Medical University, Bengbu 233000, Anhui, China; Anhui Engineering Research Center for Neural Regeneration Technology and Medical New Materials, Bengbu Medical University, Bengbu, 233000, China
| | - Gaofeng Liu
- School of Life Sciences, Bengbu Medical University, Bengbu 233000, Anhui, China; Anhui Engineering Research Center for Neural Regeneration Technology and Medical New Materials, Bengbu Medical University, Bengbu, 233000, China.
| | - Yu Guo
- School of Laboratory Medicine, Bengbu Medical University, Bengbu 233000, Anhui, China; Anhui Engineering Research Center for Neural Regeneration Technology and Medical New Materials, Bengbu Medical University, Bengbu, 233000, China.
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2
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Klein P, Petrić Howe M, Harley J, Crook H, Esteban Serna S, Roumeliotis TI, Choudhary JS, Chakrabarti AM, Luisier R, Patani R, Ramos A. m6a methylation orchestrates IMP1 regulation of microtubules during human neuronal differentiation. Nat Commun 2024; 15:4819. [PMID: 38844464 PMCID: PMC11156911 DOI: 10.1038/s41467-024-49139-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 05/21/2024] [Indexed: 06/09/2024] Open
Abstract
Neuronal differentiation requires building a complex intracellular architecture, and therefore the coordinated regulation of defined sets of genes. RNA-binding proteins (RBPs) play a key role in this regulation. However, while their action on individual mRNAs has been explored in depth, the mechanisms used to coordinate gene expression programs shaping neuronal morphology are poorly understood. To address this, we studied how the paradigmatic RBP IMP1 (IGF2BP1), an essential developmental factor, selects and regulates its RNA targets during the human neuronal differentiation. We perform a combination of system-wide and molecular analyses, revealing that IMP1 developmentally transitions to and directly regulates the expression of mRNAs encoding essential regulators of the microtubule network, a key component of neuronal morphology. Furthermore, we show that m6A methylation drives the selection of specific IMP1 mRNA targets and their protein expression during the developmental transition from neural precursors to neurons, providing a molecular principle for the onset of target selectivity.
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Affiliation(s)
- Pierre Klein
- Division of Biosciences, Institute of Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London, WC1E 6XA, UK
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Marija Petrić Howe
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Jasmine Harley
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Harry Crook
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Sofia Esteban Serna
- Division of Biosciences, Institute of Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London, WC1E 6XA, UK
| | - Theodoros I Roumeliotis
- Functional Proteomics team, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
| | - Jyoti S Choudhary
- Functional Proteomics team, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
| | - Anob M Chakrabarti
- RNA Networks Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Raphaëlle Luisier
- Idiap Research Institute, Martigny, 1920, Switzerland
- SIB Swiss Institute of Bioinformatics, Lausanne, 1015, Switzerland
| | - Rickie Patani
- Human Stem Cells and Neurodegeneration Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK.
| | - Andres Ramos
- Division of Biosciences, Institute of Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London, WC1E 6XA, UK.
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Shim T, Kim JY, Kim W, Lee YI, Cho B, Moon C. Cullin-RING E3 ubiquitin ligase 4 regulates neurite morphogenesis during neurodevelopment. iScience 2024; 27:108933. [PMID: 38318354 PMCID: PMC10839267 DOI: 10.1016/j.isci.2024.108933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/30/2023] [Accepted: 01/12/2024] [Indexed: 02/07/2024] Open
Abstract
Neuritogenesis is crucial for establishing proper neuronal connections during brain development; its failure causes neurodevelopmental defects. Cullin-RING E3 ubiquitin ligase complexes participate in various neurodevelopmental processes by regulating protein stability. We demonstrated the regulatory function of Cullin-RING E3 ubiquitin ligase 4 (CRL4) in neurite morphogenesis during early neurodevelopment. Cul4a and Cul4b, the core scaffold proteins of CRL4, exhibit high expression and activation within the cytosol of developing neurons, regulated by neuronal stimulation through N-methyl D-aspartate (NMDA) receptor signaling. CRL4 also interacts with cytoskeleton-regulating proteins involved in neurite morphogenesis. Notably, genetic depletion and inhibition of cytosolic CRL4 enhance neurite extension and branching in developing neurons. Conversely, Cul4a overexpression suppresses basal and NMDA-enhanced neuritogenesis. Furthermore, CRL4 and its substrate adaptor regulate the polyubiquitination and proteasomal degradation of doublecortin protein. Collectively, our findings suggest that CRL4 ensures proper neurite morphogenesis in developing neurons by regulating cytoskeleton-regulating proteins.
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Affiliation(s)
- Tammy Shim
- Department of Brain Sciences, DGIST, Daegu 42988, Republic of Korea
- Convergence Research Advanced Centre for Olfaction, DGIST, Daegu 42988, Republic of Korea
| | - Jae Yeon Kim
- Department of Neurology, University of California, San Francisco, CA 94143, USA
| | - WonCheol Kim
- Department of Brain Sciences, DGIST, Daegu 42988, Republic of Korea
- Convergence Research Advanced Centre for Olfaction, DGIST, Daegu 42988, Republic of Korea
| | - Yun-Il Lee
- Division of Biotechnology, DGIST, Daegu 42988, Republic of Korea
| | - Bongki Cho
- Division of Biotechnology, DGIST, Daegu 42988, Republic of Korea
| | - Cheil Moon
- Department of Brain Sciences, DGIST, Daegu 42988, Republic of Korea
- Convergence Research Advanced Centre for Olfaction, DGIST, Daegu 42988, Republic of Korea
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4
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Liu R, Liang X, Guo H, Li S, Yao W, Dong C, Wu J, Lu Y, Tang J, Zhang H. STNM1 in human cancers: role, function and potential therapy sensitizer. Cell Signal 2023:110775. [PMID: 37331415 DOI: 10.1016/j.cellsig.2023.110775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/23/2023] [Accepted: 06/14/2023] [Indexed: 06/20/2023]
Abstract
STMN1 belongs to the stathmin gene family, it encodes a cytoplasmic phosphorylated protein, stathmin1, which is commonly observed in vertebrate cells. STMN1 is a structural microtubule-associated protein (MAP) that binds to microtubule protein dimers rather than microtubules, with each STMN1 binding two microtubule protein dimers and preventing their aggregation, leading to microtubule instability. STMN1 expression is elevated in a number of malignancies, and inhibition of its expression can interfere with tumor cell division. Its expression can change the division of tumor cells, thereby arresting cell growth in the G2/M phase. Moreover, STMN1 expression affects tumor cell sensitivity to anti-microtubule drug analogs, including vincristine and paclitaxel. The research on MAPs is limited, and new insights on the mechanism of STMN1 in different cancers are emerging. The effective application of STMN1 in cancer prognosis and treatment requires further understanding of this protein. Here, we summarize the general characteristics of STMN1 and outline how STMN1 plays a role in cancer development, targeting multiple signaling networks and acting as a downstream target for multiple microRNAs, circRNAs, and lincRNAs. We also summarize recent findings on the function role of STMN1 in tumor resistance and as a therapeutic target for cancer.
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Affiliation(s)
- Ruiqi Liu
- Cancer Center, Department of Radiation Oncology, Zhejiang Provincial People's Hospital, (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou Medical College, Hangzhou, Zhejiang, China; Graduate Department, Bengbu Medical College, Bengbu, Anhui, China
| | - Xiaodong Liang
- Cancer Center, Department of Radiation Oncology, Zhejiang Provincial People's Hospital, (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou Medical College, Hangzhou, Zhejiang, China; Graduate Department, Bengbu Medical College, Bengbu, Anhui, China
| | - Haiwei Guo
- Otolaryngology & Head and Neck Center, Cancer Center, Department of Head and Neck Surgery, Zhejiang Provincial People's Hospital, (Affiliated People's Hospital Hangzhou Medical College), Hangzhou, Zhejiang, China
| | - Shuang Li
- Cancer Center, Department of Radiation Oncology, Zhejiang Provincial People's Hospital, (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Weiping Yao
- Cancer Center, Department of Radiation Oncology, Zhejiang Provincial People's Hospital, (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou Medical College, Hangzhou, Zhejiang, China; Graduate Department, Bengbu Medical College, Bengbu, Anhui, China
| | - Chenfang Dong
- Cancer Center, Department of Radiation Oncology, Zhejiang Provincial People's Hospital, (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou Medical College, Hangzhou, Zhejiang, China; Zhejiang Key Laboratory for Disease Proteomics, Zhejiang University School of Medicine, Hangzhou, China
| | - Jiajun Wu
- Graduate Department, Bengbu Medical College, Bengbu, Anhui, China; Otolaryngology & Head and Neck Center, Cancer Center, Department of Head and Neck Surgery, Zhejiang Provincial People's Hospital, (Affiliated People's Hospital Hangzhou Medical College), Hangzhou, Zhejiang, China
| | - Yanwei Lu
- Cancer Center, Department of Radiation Oncology, Zhejiang Provincial People's Hospital, (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Jianming Tang
- Department of Radiation Oncology, The First Hospital of Lanzhou University, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Haibo Zhang
- Cancer Center, Department of Radiation Oncology, Zhejiang Provincial People's Hospital, (Affiliated People's Hospital, Hangzhou Medical College), Hangzhou Medical College, Hangzhou, Zhejiang, China.
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5
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Mohylyak I, Bengochea M, Pascual-Caro C, Asfogo N, Fonseca-Topp S, Danda N, Atak ZK, De Waegeneer M, Plaçais PY, Preat T, Aerts S, Corti O, de Juan-Sanz J, Hassan BA. Developmental transcriptional control of mitochondrial homeostasis is required for activity-dependent synaptic connectivity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.11.544500. [PMID: 37333418 PMCID: PMC10274921 DOI: 10.1101/2023.06.11.544500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
During neuronal circuit formation, local control of axonal organelles ensures proper synaptic connectivity. Whether this process is genetically encoded is unclear and if so, its developmental regulatory mechanisms remain to be identified. We hypothesized that developmental transcription factors regulate critical parameters of organelle homeostasis that contribute to circuit wiring. We combined cell type-specific transcriptomics with a genetic screen to discover such factors. We identified Telomeric Zinc finger-Associated Protein (TZAP) as a temporal developmental regulator of neuronal mitochondrial homeostasis genes, including Pink1 . In Drosophila , loss of dTzap function during visual circuit development leads to loss of activity-dependent synaptic connectivity, that can be rescued by Pink1 expression. At the cellular level, loss of dTzap/TZAP leads to defects in mitochondrial morphology, attenuated calcium uptake and reduced synaptic vesicle release in fly and mammalian neurons. Our findings highlight developmental transcriptional regulation of mitochondrial homeostasis as a key factor in activity-dependent synaptic connectivity.
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6
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Schmitd LB, Perez-Pacheco C, Bellile EL, Wu W, Casper K, Mierzwa M, Rozek LS, Wolf GT, Taylor JM, D'Silva NJ. Spatial and Transcriptomic Analysis of Perineural Invasion in Oral Cancer. Clin Cancer Res 2022; 28:3557-3572. [PMID: 35819260 PMCID: PMC9560986 DOI: 10.1158/1078-0432.ccr-21-4543] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/25/2022] [Accepted: 05/24/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE Perineural invasion (PNI), a common occurrence in oral squamous cell carcinomas, is associated with poor survival. Consequently, these tumors are treated aggressively. However, diagnostic criteria of PNI vary and its role as an independent predictor of prognosis has not been established. To address these knowledge gaps, we investigated spatial and transcriptomic profiles of PNI-positive and PNI-negative nerves. EXPERIMENTAL DESIGN Tissue sections from 142 patients were stained with S100 and cytokeratin antibodies. Nerves were identified in two distinct areas: tumor bulk and margin. Nerve diameter and nerve-to-tumor distance were assessed; survival analyses were performed. Spatial transcriptomic analysis of nerves at varying distances from tumor was performed with NanoString GeoMx Digital Spatial Profiler Transcriptomic Atlas. RESULTS PNI is an independent predictor of poor prognosis among patients with metastasis-free lymph nodes. Patients with close nerve-tumor distance have poor outcomes even if diagnosed as PNI negative using current criteria. Patients with large nerve(s) in the tumor bulk survive poorly, suggesting that even PNI-negative nerves facilitate tumor progression. Diagnostic criteria were supported by spatial transcriptomic analyses of >18,000 genes; nerves in proximity to cancer exhibit stress and growth response changes that diminish with increasing nerve-tumor distance. These findings were validated in vitro and in human tissue. CONCLUSIONS This is the first study in human cancer with high-throughput gene expression analysis in nerves with striking correlations between transcriptomic profile and clinical outcomes. Our work illuminates nerve-cancer interactions suggesting that cancer-induced injury modulates neuritogenesis, and supports reclassification of PNI based on nerve-tumor distance rather than current subjective criteria.
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Affiliation(s)
- Ligia B. Schmitd
- Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, Michigan
| | - Cindy Perez-Pacheco
- Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, Michigan
| | - Emily L. Bellile
- Biostatistics, University of Michigan School of Public Health, Ann Arbor, Michigan
| | - Weisheng Wu
- Bioinformatics Core, University of Michigan, Ann Arbor, Michigan
| | - Keith Casper
- Otolaryngology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Michelle Mierzwa
- Radiation Oncology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Laura S. Rozek
- Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan
| | - Gregory T. Wolf
- Otolaryngology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Jeremy M.G. Taylor
- Biostatistics, University of Michigan School of Public Health, Ann Arbor, Michigan
- Radiation Oncology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Nisha J. D'Silva
- Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, Michigan
- Pathology, University of Michigan Medical School, Ann Arbor, Michigan
- Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan
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7
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Cheon S, Culver AM, Bagnell AM, Ritchie FD, Vacharasin JM, McCord MM, Papendorp CM, Chukwurah E, Smith AJ, Cowen MH, Moreland TA, Ghate PS, Davis SW, Liu JS, Lizarraga SB. Counteracting epigenetic mechanisms regulate the structural development of neuronal circuitry in human neurons. Mol Psychiatry 2022; 27:2291-2303. [PMID: 35210569 PMCID: PMC9133078 DOI: 10.1038/s41380-022-01474-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 02/02/2022] [Indexed: 01/23/2023]
Abstract
Autism spectrum disorders (ASD) are associated with defects in neuronal connectivity and are highly heritable. Genetic findings suggest that there is an overrepresentation of chromatin regulatory genes among the genes associated with ASD. ASH1 like histone lysine methyltransferase (ASH1L) was identified as a major risk factor for ASD. ASH1L methylates Histone H3 on Lysine 36, which is proposed to result primarily in transcriptional activation. However, how mutations in ASH1L lead to deficits in neuronal connectivity associated with ASD pathogenesis is not known. We report that ASH1L regulates neuronal morphogenesis by counteracting the catalytic activity of Polycomb Repressive complex 2 group (PRC2) in stem cell-derived human neurons. Depletion of ASH1L decreases neurite outgrowth and decreases expression of the gene encoding the neurotrophin receptor TrkB whose signaling pathway is linked to neuronal morphogenesis. The neuronal morphogenesis defect is overcome by inhibition of PRC2 activity, indicating that a balance between the Trithorax group protein ASH1L and PRC2 activity determines neuronal morphology. Thus, our work suggests that ASH1L may epigenetically regulate neuronal morphogenesis by modulating pathways like the BDNF-TrkB signaling pathway. Defects in neuronal morphogenesis could potentially impair the establishment of neuronal connections which could contribute to the neurodevelopmental pathogenesis associated with ASD in patients with ASH1L mutations.
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Affiliation(s)
- Seonhye Cheon
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Allison M Culver
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Anna M Bagnell
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Foster D Ritchie
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Janay M Vacharasin
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Mikayla M McCord
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Carin M Papendorp
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
| | - Evelyn Chukwurah
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Austin J Smith
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Mara H Cowen
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Trevor A Moreland
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Pankaj S Ghate
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Shannon W Davis
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA
| | - Judy S Liu
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, Brown University, Providence, RI, USA
- Department of Neurology, Rhode Island Hospital and Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Sofia B Lizarraga
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA.
- Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, USA.
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Engmann AK, Hatch JJ, Nanda P, Veeraraghavan P, Ozkan A, Poulopoulos A, Murphy AJ, Macklis JD. Neuronal subtype-specific growth cone and soma purification from mammalian CNS via fractionation and fluorescent sorting for subcellular analyses and spatial mapping of local transcriptomes and proteomes. Nat Protoc 2022; 17:222-251. [PMID: 35022617 PMCID: PMC9751848 DOI: 10.1038/s41596-021-00638-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 09/24/2021] [Indexed: 11/09/2022]
Abstract
During neuronal development, growth cones (GCs) of projection neurons navigate complex extracellular environments to reach distant targets, thereby generating extraordinarily complex circuitry. These dynamic structures located at the tips of axonal projections respond to substrate-bound as well as diffusible guidance cues in a neuronal subtype- and stage-specific manner to construct highly specific and functional circuitry. In vitro studies of the past decade indicate that subcellular localization of specific molecular machinery in GCs underlies the precise navigational control that occurs during circuit 'wiring'. Our laboratory has recently developed integrated experimental and analytical approaches enabling high-depth, quantitative proteomic and transcriptomic investigation of subtype- and stage-specific GC molecular machinery directly from the rodent central nervous system (CNS) in vivo. By using these approaches, a pure population of GCs and paired somata can be isolated from any neuronal subtype of the CNS that can be fluorescently labeled. GCs are dissociated from parent axons using fluid shear forces, and a bulk GC fraction is isolated by buoyancy ultracentrifugation. Subtype-specific GCs and somata are purified by recently developed fluorescent small particle sorting and established FACS of neurons and are suitable for downstream analyses of proteins and RNAs, including small RNAs. The isolation of subtype-specific GCs and parent somata takes ~3 h, plus sorting time, and ~1-2 h for subsequent extraction of molecular contents. RNA library preparation and sequencing can take several days to weeks, depending on the turnaround time of the core facility involved.
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Affiliation(s)
- Anne K Engmann
- Department of Stem Cell and Regenerative Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - John J Hatch
- Department of Stem Cell and Regenerative Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Prakruti Nanda
- Department of Stem Cell and Regenerative Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Priya Veeraraghavan
- Department of Stem Cell and Regenerative Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Abdulkadir Ozkan
- Department of Stem Cell and Regenerative Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Alexandros Poulopoulos
- Department of Stem Cell and Regenerative Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Alexander J Murphy
- Department of Stem Cell and Regenerative Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA
- Takeda Pharmaceutical Company Limited, Cambridge, MA, USA
| | - Jeffrey D Macklis
- Department of Stem Cell and Regenerative Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA.
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Dey S, Ghosh-Roy A. In vivo Assessment of Microtubule Dynamics and Orientation in Caenorhabditis elegans Neurons. J Vis Exp 2021:10.3791/62744. [PMID: 34866634 PMCID: PMC7614928 DOI: 10.3791/62744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
In neurons, microtubule orientation has been a key assessor to identify axons that have plus-end out microtubules and dendrites that generally have mixed orientation. Here we describe methods to label, image, and analyze the microtubule dynamics and growth during the development and regeneration of touch neurons in C. elegans. Using genetically encoded fluorescent reporters of microtubule tips, we imaged the axonal microtubules. The local changes in microtubule behavior that initiates axon regeneration following axotomy can be quantified using this protocol. This assay is adaptable to other neurons and genetic backgrounds to investigate the regulation of microtubule dynamics in various cellular processes.
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10
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A Propagated Skeleton Approach to High Throughput Screening of Neurite Outgrowth for In Vitro Parkinson's Disease Modelling. Cells 2021; 10:cells10040931. [PMID: 33920556 PMCID: PMC8072564 DOI: 10.3390/cells10040931] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 11/16/2022] Open
Abstract
Neuronal models of neurodegenerative diseases such as Parkinson's Disease (PD) are extensively studied in pathological and therapeutical research with neurite outgrowth being a core feature. Screening of neurite outgrowth enables characterization of various stimuli and therapeutic effects after lesion. In this study, we describe an autonomous computational assay for a high throughput skeletonization approach allowing for quantification of neurite outgrowth in large data sets from fluorescence microscopic imaging. Development and validation of the assay was conducted with differentiated SH-SY5Y cells and primary mesencephalic dopaminergic neurons (MDN) treated with the neurotoxic lesioning compound Rotenone. Results of manual annotation using NeuronJ and automated data were shown to correlate strongly (R2-value 0.9077 for SH-SY5Y cells and R2-value 0.9297 for MDN). Pooled linear regressions of results from SH-SY5Y cell image data could be integrated into an equation formula (y=0.5410·x+1792; y=0.8789·x+0.09191 for normalized results) with y depicting automated and x depicting manual data. This automated neurite length algorithm constitutes a valuable tool for modelling of neurite outgrowth that can be easily applied to evaluate therapeutic compounds with high throughput approaches.
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Mei Y, Liu Y, Ji P. Understanding terminal erythropoiesis: An update on chromatin condensation, enucleation, and reticulocyte maturation. Blood Rev 2021; 46:100740. [PMID: 32798012 DOI: 10.1016/j.blre.2020.100740] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/02/2020] [Accepted: 08/05/2020] [Indexed: 12/19/2022]
Abstract
A characteristic feature of terminal erythropoiesis in mammals is extrusion of the highly condensed nucleus out of the cytoplasm. Other vertebrates, including fish, reptiles, amphibians, and birds, undergo nuclear condensation but do not enucleate. Enucleation provides mammals evolutionary advantages by gaining extra space for hemoglobin and being more flexible to migrate through capillaries. Nascent reticulocytes further mature into red blood cells through membrane and proteome remodeling and organelle clearance. Over the past decade, novel molecular mechanisms and signaling pathways have been uncovered that play important roles in chromatin condensation, enucleation, and reticulocyte maturation. These advances not only increase understanding of the physiology of erythropoiesis, but also facilitate efforts in generating in vitro red blood cells for various translational application. In the present review, recent studies in epigenetic modification and release of histones during chromatin condensation are highlighted. New insights in enucleation, including protein sorting, vesicle trafficking, transcriptional regulation, noncoding RNA, cytoskeleton remodeling, erythroblastic islands, and cytokinesis, are summarized. Moreover, organelle clearance and proteolysis mediated by ubiquitin-proteasome degradation during reticulocytes maturation is also examined. Perspectives for future directions in this rapidly evolving research area are also provided.
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Affiliation(s)
- Yang Mei
- Department of Pathology, Northwestern University, Chicago, IL, USA.
| | - Yijie Liu
- Department of Pathology, Northwestern University, Chicago, IL, USA.
| | - Peng Ji
- Department of Pathology, Northwestern University, Chicago, IL, USA.
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12
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Dong Z, Chen X, Li Y, Zhuo R, Lai X, Liu M. Microtubule Severing Protein Fignl2 Contributes to Endothelial and Neuronal Branching in Zebrafish Development. Front Cell Dev Biol 2021; 8:593234. [PMID: 33585441 PMCID: PMC7873885 DOI: 10.3389/fcell.2020.593234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 12/21/2020] [Indexed: 11/13/2022] Open
Abstract
Previously, fidgetin (fign) and its family members fidgetin-like 1 (fignl1) and fidgetin-like 2 (fignl2) were found to be highly expressed during zebrafish brain development, suggesting their functions in the nervous system. In this study, we report the effects of loss-of-function of these genes on development. We designed and identified single-guide RNAs targeted to generate fign, fignl1, and fignl2 mutants and then observed the overall morphological and behavioral changes. Our findings showed that while fign and fignl1 null mutants displayed no significant defects, fignl2 null zebrafish mutants displayed pericardial edema, reduced heart rate, and smaller eyes; fignl2 null mutants responded to the light-darkness shift with a lower swimming velocity. fignl2 mRNAs were identified in vascular endothelial cells by in situ hybridization and re-analysis of an online dataset of single-cell RNAseq results. Finally, we used morpholino oligonucleotides to confirm that fignl2 knockdown resulted in severe heart edema, which was caused by abnormal vascular branching. The zebrafish fignl2 morphants also showed longer axonal length and more branches of caudal primary neurons. Taken together, we summarize that Fignl2 functions on cellular branches in endothelial cells and neurons. This study reported for the first time that the microtubule-severing protein Fignl2 contributes to cell branching during development.
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Affiliation(s)
- Zhangji Dong
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Xu Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Yuanyuan Li
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Run Zhuo
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Xiaona Lai
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Mei Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
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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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Expression of a novel brain specific isoform of C3G is regulated during development. Sci Rep 2020; 10:18838. [PMID: 33139841 PMCID: PMC7606606 DOI: 10.1038/s41598-020-75813-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 10/01/2020] [Indexed: 12/13/2022] Open
Abstract
Mice lacking C3G (RapGEF1), a ubiquitously expressed protein essential for neuronal differentiation, show multiple defects in brain development. Function of C3G in neurogenesis is poorly defined. Here, we identify brain specific expression of a novel C3G isoform in mice and humans. This isoform has an insert in the Crk-binding region, generating a polypeptide of 175 kDa, unlike the previously known 140 kDa form expressed in all other tissues. In the adult mouse brain, C3G expression is seen in neurons, but was not detectable in GFAP-positive cells. C3G levels were high in the CA3 region of hippocampus and in mitral cells of olfactory bulb. Neural progenitor cells positive for Doublecortin and Nestin, show expression of C3G. During development, C3G is expressed in precursor cells prior to their differentiation into mature neurons or astrocytes. The 175 kDa as well as 140 kDa forms are seen in embryonic mouse brain, while only the 175 kDa variant is seen in post-natal brain. Human cerebral organoids generated from induced pluripotent stem cells predominantly expressed the 140 kDa polypeptides, and the 175 kDa isoform appeared upon maturation. This study describes developmental regulation and neuronal expression of a brain specific isoform of C3G, a molecule essential for normal development of the mammalian brain.
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Microtubule Dysfunction: A Common Feature of Neurodegenerative Diseases. Int J Mol Sci 2020; 21:ijms21197354. [PMID: 33027950 PMCID: PMC7582320 DOI: 10.3390/ijms21197354] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 09/24/2020] [Accepted: 10/01/2020] [Indexed: 12/13/2022] Open
Abstract
Neurons are particularly susceptible to microtubule (MT) defects and deregulation of the MT cytoskeleton is considered to be a common insult during the pathogenesis of neurodegenerative disorders. Evidence that dysfunctions in the MT system have a direct role in neurodegeneration comes from findings that several forms of neurodegenerative diseases are associated with changes in genes encoding tubulins, the structural units of MTs, MT-associated proteins (MAPs), or additional factors such as MT modifying enzymes which modulating tubulin post-translational modifications (PTMs) regulate MT functions and dynamics. Efforts to use MT-targeting therapeutic agents for the treatment of neurodegenerative diseases are underway. Many of these agents have provided several benefits when tested on both in vitro and in vivo neurodegenerative model systems. Currently, the most frequently addressed therapeutic interventions include drugs that modulate MT stability or that target tubulin PTMs, such as tubulin acetylation. The purpose of this review is to provide an update on the relevance of MT dysfunctions to the process of neurodegeneration and briefly discuss advances in the use of MT-targeting drugs for the treatment of neurodegenerative disorders.
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16
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Brosig A, Fuchs J, Ipek F, Kroon C, Schrötter S, Vadhvani M, Polyzou A, Ledderose J, van Diepen M, Holzhütter HG, Trimbuch T, Gimber N, Schmoranzer J, Lieberam I, Rosenmund C, Spahn C, Scheerer P, Szczepek M, Leondaritis G, Eickholt BJ. The Axonal Membrane Protein PRG2 Inhibits PTEN and Directs Growth to Branches. Cell Rep 2020; 29:2028-2040.e8. [PMID: 31722215 PMCID: PMC6856728 DOI: 10.1016/j.celrep.2019.10.039] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 08/09/2019] [Accepted: 10/09/2019] [Indexed: 01/03/2023] Open
Abstract
In developing neurons, phosphoinositide 3-kinases (PI3Ks) control axon growth and branching by positively regulating PI3K/PI(3,4,5)P3, but how neurons are able to generate sufficient PI(3,4,5)P3 in the presence of high levels of the antagonizing phosphatase PTEN is difficult to reconcile. We find that normal axon morphogenesis involves homeostasis of elongation and branch growth controlled by accumulation of PI(3,4,5)P3 through PTEN inhibition. We identify a plasma membrane-localized protein-protein interaction of PTEN with plasticity-related gene 2 (PRG2). PRG2 stabilizes membrane PI(3,4,5)P3 by inhibiting PTEN and localizes in nanoclusters along axon membranes when neurons initiate their complex branching behavior. We demonstrate that PRG2 is both sufficient and necessary to account for the ability of neurons to generate axon filopodia and branches in dependence on PI3K/PI(3,4,5)P3 and PTEN. Our data indicate that PRG2 is part of a neuronal growth program that induces collateral branch growth in axons by conferring local inhibition of PTEN. Neuronal axon growth and branching is globally regulated by PI3K/PTEN signaling PRG2 inhibits PTEN and stabilizes PIP3 and F-actin PRG2 localizes to nanoclusters on the axonal membrane and coincides with branching PRG2 promotes axonal filopodia and branching dependent on PI3K/PTEN
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Affiliation(s)
- Annika Brosig
- Institute of Biochemistry, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Joachim Fuchs
- Institute of Biochemistry, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Fatih Ipek
- Institute of Biochemistry, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Cristina Kroon
- Institute of Biochemistry, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Sandra Schrötter
- Institute of Biochemistry, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Department of Genetics and Complex Diseases, T.H. Chan Harvard School of Public Health, Boston, MA 02120, USA
| | - Mayur Vadhvani
- Institute of Biochemistry, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Alexandra Polyzou
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece
| | - Julia Ledderose
- Institute of Biochemistry, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Michiel van Diepen
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Science, University of Cape Town, Cape Town, South Africa
| | - Hermann-Georg Holzhütter
- Institute of Biochemistry, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Thorsten Trimbuch
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Niclas Gimber
- Advanced Medical Bioimaging Core Facility (AMBIO), Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Jan Schmoranzer
- Advanced Medical Bioimaging Core Facility (AMBIO), Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Ivo Lieberam
- Centre for Stem Cells and Regenerative Medicine and Centre for Developmental Neurobiology, MRC Centre for Neurodevelopmental Disorders, King's College, London, UK
| | - Christian Rosenmund
- NeuroCure-Cluster of Excellence, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Christian Spahn
- NeuroCure-Cluster of Excellence, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Institute of Medical Physics and Biophysics, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Patrick Scheerer
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Michal Szczepek
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - George Leondaritis
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece.
| | - Britta J Eickholt
- Institute of Biochemistry, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; NeuroCure-Cluster of Excellence, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
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17
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Schmuck MR, Keil KP, Sethi S, Morgan RK, Lein PJ. Automated high content image analysis of dendritic arborization in primary mouse hippocampal and rat cortical neurons in culture. J Neurosci Methods 2020; 341:108793. [PMID: 32461071 PMCID: PMC7357201 DOI: 10.1016/j.jneumeth.2020.108793] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 04/17/2020] [Accepted: 05/18/2020] [Indexed: 01/28/2023]
Abstract
BACKGROUND Primary neuronal cell cultures are useful for studying mechanisms that influence dendritic morphology during normal development and in response to various stressors. However, analyzing dendritic morphology is challenging, particularly in cultures with high cell density, and manual methods of selecting neurons and tracing dendritic arbors can introduce significant bias, and are labor-intensive. To overcome these challenges, semi-automated and automated methods are being developed, with most software solutions requiring computer-assisted dendrite tracing with subsequent quantification of various parameters of dendritic morphology, such as Sholl analysis. However fully automated approaches for classic Sholl analysis of dendritic complexity are not currently available. NEW METHOD The previously described Omnisphero software, was extended by adding new functions to automatically assess dendritic mass, total length of the dendritic arbor and the number of primary dendrites, branch points, and terminal tips, and to perform Sholl analysis. RESULTS The new functions for assessing dendritic morphology were validated using primary mouse hippocampal and rat cortical neurons transfected with a fluorescently tagged MAP2 cDNA construct. These functions allow users to select specific populations of neurons as a training set for subsequent automated selection of labeled neurons in high-density cultures. COMPARISON WITH EXISTING SEMI-AUTOMATED METHODS Compared to manual or semi-automated analyses of dendritic arborization, the new functions increase throughput while significantly decreasing researcher bias associated with neuron selection, tracing, and thresholding. CONCLUSION These results demonstrate the importance of using unbiased automated methods to mitigate experimenter-dependent bias in analyzing dendritic morphology.
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Affiliation(s)
- Martin R Schmuck
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
| | - Kimberly P Keil
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
| | - Sunjay Sethi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
| | - Rhianna K Morgan
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
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18
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Gallop J. Filopodia and their links with membrane traffic and cell adhesion. Semin Cell Dev Biol 2020; 102:81-89. [DOI: 10.1016/j.semcdb.2019.11.017] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 11/14/2019] [Accepted: 11/28/2019] [Indexed: 01/24/2023]
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19
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Verheijen BM. Expression Profile of Long Non-Coding RNAs during Early Postnatal Development of Mouse Spinal Cord. Noncoding RNA 2020; 6:ncrna6020018. [PMID: 32443580 DOI: 10.3390/ncrna6020018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/13/2020] [Accepted: 05/14/2020] [Indexed: 01/03/2023] Open
Abstract
Long non-coding RNAs (lncRNAs) are a diverse class of transcripts that are >200 nucleotides long and lack significant protein-coding potential. LncRNAs are emerging as major regulators of gene expression networks in various physiological and pathological processes. Interestingly, many lncRNAs show tissue-specific expression, for example, in the nervous system. Although lncRNAs have been suggested to play key roles in the brain, most functions of neural lncRNAs remain poorly understood. In order to provide a catalog of lncRNA changes that occur in spinal cord during early postnatal development, RNA from mouse spinal cord was sequenced at different time points in the first week after birth (postnatal day 1 and postnatal day 7). Two hundred and ninty-six differentially expressed lncRNAs (FDR < 0.05) were identified in the resulting dataset. Altered transcripts were associated with several biological processes including myelination, neural differentiation, and glial cell development. PCR validation confirmed differential expression of select lncRNAs (i.e., Cerox1, lncOL3, Neat1, and Sox2ot). Additionally, analysis of circular RNAs (circRNAs), another class of non-coding RNA with regulatory potency, pointed out a number of circRNAs associated with spinal cord development. These data can be used as a resource for future studies on transcriptional changes during early postnatal nervous system development and studies of disorders that affect the spinal cord, e.g., spinal muscular atrophy.
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Affiliation(s)
- Bert M Verheijen
- Department of Translational Neuroscience, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
- Laboratory for Experimental Neurology, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
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20
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Nestin Selectively Facilitates the Phosphorylation of the Lissencephaly-Linked Protein Doublecortin (DCX) by cdk5/p35 to Regulate Growth Cone Morphology and Sema3a Sensitivity in Developing Neurons. J Neurosci 2020; 40:3720-3740. [PMID: 32273484 DOI: 10.1523/jneurosci.2471-19.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/24/2020] [Accepted: 03/24/2020] [Indexed: 11/21/2022] Open
Abstract
Nestin, an intermediate filament protein widely used as a marker of neural progenitors, was recently found to be expressed transiently in developing cortical neurons in culture and in developing mouse cortex. In young cortical cultures, nestin regulates axonal growth cone morphology. In addition, nestin, which is known to bind the neuronal cdk5/p35 kinase, affects responses to axon guidance cues upstream of cdk5, specifically, to Sema3a. Changes in growth cone morphology require rearrangements of cytoskeletal networks, and changes in microtubules and actin filaments are well studied. In contrast, the roles of intermediate filament proteins in this process are poorly understood, even in cultured neurons. Here, we investigate the molecular mechanism by which nestin affects growth cone morphology and Sema3a sensitivity. We find that nestin selectively facilitates the phosphorylation of the lissencephaly-linked protein doublecortin (DCX) by cdk5/p35, but the phosphorylation of other cdk5 substrates is not affected by nestin. We uncover that this substrate selectivity is based on the ability of nestin to interact with DCX, but not with other cdk5 substrates. Nestin thus creates a selective scaffold for DCX with activated cdk5/p35. Last, we use cortical cultures derived from Dcx KO mice to show that the effects of nestin on growth cone morphology and on Sema3a sensitivity are DCX-dependent, thus suggesting a functional role for the DCX-nestin complex in neurons. We propose that nestin changes growth cone behavior by regulating the intracellular kinase signaling environment in developing neurons. The sex of animal subjects is unknown.SIGNIFICANCE STATEMENT Nestin, an intermediate filament protein highly expressed in neural progenitors, was recently identified in developing neurons where it regulates growth cone morphology and responsiveness to the guidance cue Sema3a. Changes in growth cone morphology require rearrangements of cytoskeletal networks, but the roles of intermediate filaments in this process are poorly understood. We now report that nestin selectively facilitates phosphorylation of the lissencephaly-linked doublecortin (DCX) by cdk5/p35, but the phosphorylation of other cdk5 substrates is not affected. This substrate selectivity is based on preferential scaffolding of DCX, cdk5, and p35 by nestin. Additionally, we demonstrate a functional role for the DCX-nestin complex in neurons. We propose that nestin changes growth cone behavior by regulating intracellular kinase signaling in developing neurons.
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21
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Lee VM, Hernandez S, Giang B, Chabot C, Hernandez J, de Bellard ME. Molecular Events Controlling Cessation of Trunk Neural Crest Migration and Onset of Differentiation. Front Cell Dev Biol 2020; 8:199. [PMID: 32318567 PMCID: PMC7147452 DOI: 10.3389/fcell.2020.00199] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 03/09/2020] [Indexed: 12/30/2022] Open
Abstract
Neural crest cells (NCC) migrate extensively in vertebrate embryos to populate diverse derivatives including ganglia of the peripheral nervous system. Little is known about the molecular mechanisms that lead migrating trunk NCC to settle at selected sites in the embryo, ceasing their migration and initiating differentiation programs. To identify candidate genes involved in these processes, we profiled genes up-regulated in purified post-migratory compared with migratory NCC using a staged, macroarrayed cDNA library. A secondary screen of in situ hybridization revealed that many genes are specifically enhanced in neural crest-derived ganglia, including macrophage migration inhibitory factor (MIF), a ligand for CXCR4 receptor. Through in vivo and in vitro assays, we found that MIF functions as a potent chemoattractant for NCC. These results provide a molecular profile of genes expressed concomitant with gangliogenesis, thus, offering new markers and potential regulatory candidates involved in cessation of migration and onset of differentiation.
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Affiliation(s)
- Vivian M Lee
- Universal Cells Inc., Seattle, WA, United States
| | - Sergio Hernandez
- Biology Department, California State University Northridge, Northridge, CA, United States
| | - Belle Giang
- Moorpark College, Moorpark, CA, United States
| | - Chris Chabot
- Biology Department, California State University Northridge, Northridge, CA, United States
| | | | - Maria Elena de Bellard
- Biology Department, California State University Northridge, Northridge, CA, United States
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22
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Leong SY, Edzuka T, Goshima G, Yamada M. Kinesin-13 and Kinesin-8 Function during Cell Growth and Division in the Moss Physcomitrella patens. THE PLANT CELL 2020; 32:683-702. [PMID: 31919299 PMCID: PMC7054034 DOI: 10.1105/tpc.19.00521] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 10/25/2019] [Accepted: 01/07/2020] [Indexed: 05/03/2023]
Abstract
Kinesin-13 and Kinesin-8 are well-known microtubule (MT) depolymerases that regulate MT length and chromosome movement in animal mitosis. While much is unknown about plant Kinesin-8, Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) Kinesin-13 have been shown to depolymerize MTs in vitro. However, the mitotic function of both kinesins has yet to be determined in plants. Here, we generated complete null mutants of Kinesin-13 and Kinesin-8 in moss (Physcomitrella patens). Both kinesins were found to be nonessential for viability, but the Kinesin-13 knockout (KO) line had increased mitotic duration and reduced spindle length, whereas the Kinesin-8 KO line did not display obvious mitotic defects. Surprisingly, spindle MT poleward flux, which is mediated by Kinesin-13 in animals, was retained in the absence of Kinesin-13. MT depolymerase activity was not detectable for either kinesin in vitro, while MT catastrophe-inducing activity (Kinesin-13) or MT gliding activity (Kinesin-8) was observed. Interestingly, both KO lines showed waviness in their protonema filaments, which correlated with positional instability of the MT foci in their tip cells. Taken together, the results suggest that plant Kinesin-13 and Kinesin-8 have diverged in both mitotic function and molecular activity, acquiring roles in regulating MT foci positioning for directed tip growth.
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Affiliation(s)
- Shu Yao Leong
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Tomoya Edzuka
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Gohta Goshima
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Moé Yamada
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
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23
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Much More Than a Scaffold: Cytoskeletal Proteins in Neurological Disorders. Cells 2020; 9:cells9020358. [PMID: 32033020 PMCID: PMC7072452 DOI: 10.3390/cells9020358] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/27/2020] [Accepted: 01/29/2020] [Indexed: 02/08/2023] Open
Abstract
Recent observations related to the structure of the cytoskeleton in neurons and novel cytoskeletal abnormalities involved in the pathophysiology of some neurological diseases are changing our view on the function of the cytoskeletal proteins in the nervous system. These efforts allow a better understanding of the molecular mechanisms underlying neurological diseases and allow us to see beyond our current knowledge for the development of new treatments. The neuronal cytoskeleton can be described as an organelle formed by the three-dimensional lattice of the three main families of filaments: actin filaments, microtubules, and neurofilaments. This organelle organizes well-defined structures within neurons (cell bodies and axons), which allow their proper development and function through life. Here, we will provide an overview of both the basic and novel concepts related to those cytoskeletal proteins, which are emerging as potential targets in the study of the pathophysiological mechanisms underlying neurological disorders.
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RhoA-GTPase Modulates Neurite Outgrowth by Regulating the Expression of Spastin and p60-Katanin. Cells 2020; 9:cells9010230. [PMID: 31963385 PMCID: PMC7016723 DOI: 10.3390/cells9010230] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/10/2020] [Accepted: 01/14/2020] [Indexed: 12/17/2022] Open
Abstract
RhoA-GTPase (RhoA) is widely regarded as a key molecular switch to inhibit neurite outgrowth by rigidifying the actin cytoskeleton. However, during neurite outgrowth, whether and how microtubule dynamics are regulated by RhoA remains to be elucidated. Herein, CT04 and Y27632 were used to inactivate RhoA and its downstream effector Rho-associated coiled coil-forming kinase (ROCK), while the RhoAQ63L lentiviral vector was utilized to overexpress the constitutively activated RhoA in dorsal root ganglion (DRG) neurons or neuronal differentiated PC12 cells. The current data illustrate that the RhoA signaling pathway negatively modulates neurite outgrowth and elevates the expression of Glu-tubulin (a marker for a stabilized microtubule). Meanwhile, the microtubule-severing proteins spastin and p60-katanin were downregulated by the RhoA signaling pathway. When spastin and p60-katanin were knocked down, the effects of RhoA inhibition on neurite outgrowth were significantly reversed. Taken together, this study demonstrates that the RhoA pathway-mediated inhibition of neurite outgrowth is not only related to the modulation of microfilament dynamics but is also attributable to the regulation of the expression of spastin and p60-katanin and thus influences microtubule dynamics.
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Leo TK, Garba S, Abubakar D, Sazili AQ, Candyrine SCL, Jahromi MF, Goh YM, Ronimus R, Muetzel S, Liang JB. Naturally Produced Lovastatin Modifies the Histology and Proteome Profile of Goat Skeletal Muscle. Animals (Basel) 2019; 10:ani10010072. [PMID: 31906061 PMCID: PMC7022420 DOI: 10.3390/ani10010072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/11/2019] [Accepted: 11/12/2019] [Indexed: 12/11/2022] Open
Abstract
Simple Summary Enteric methane formation in ruminants is one of the major contributors to climate change. Among the potential strategies, the supplementation of naturally produced lovastatin has been reported as one of the promising approaches for the mitigation of methane emissions. Nevertheless, statins have been associated with the development of muscle-related adverse effects which could affect the health and wellbeing of the animals. We have reported previously that supplementation of naturally produced lovastatin at 2 and 4 mg/kg body weight (BW), reduced methane emissions in goats without adversely affecting rumen fermentation and animal performance, except at higher level of lovastatin (6 mg/kg BW). However, the effects of lovastatin on the skeletal muscle in goats and the associated mechanisms have not been studied. Hence, the present study aimed to examine the effects of lovastatin on the histology of the goat skeletal muscle from the above study and to further elucidate the related underlying biochemistry processes. Histology analysis observed marked degeneration in the longissimus thoracis et lumborum muscle of goats supplemented with 6 mg lovastatin/kg BW. Our preliminary label-free proteomics analysis identified approximately 400 proteins in total, a number of which were differentially expressed, which are involved in energy metabolism and may have contributed to the observed skeletal muscle damage above 4 mg/kg BW. Abstract This study was conducted to examine the effects of different levels of lovastatin on the histological and sarcoplasmic proteome profile of goat skeletal muscle. A total of 20 intact male Saanen goats were randomly assigned in equal numbers to four groups and fed a total mixed ration containing 50% rice straw, 22.8% concentrates and 27.2% of various proportions of untreated or treated palm kernel cake (PKC) to achieve the target daily intake levels of 0 (Control), 2 (Low), 4 (Medium) or 6 (High) mg lovastatin/kg BW. A histological examination discovered that the longissimus thoracis et lumborum muscle of animals from the Medium and High treatment groups showed abnormalities in terms of necrosis, degeneration, interstitial space and vacuolization. Our preliminary label-free proteomics analysis demonstrates that lovastatin supplementation induced complex modifications to the protein expression patterns of the skeletal muscle of the goat which were associated with the metabolism of carbohydrate and creatine, cell growth and development processes and other metabolic processes. The changes in these biochemical processes indicate perturbations in energy metabolism, which could play a major role in the development of myopathy. In conclusion, the present study suggests that supplementation of naturally produced lovastatin above 4 mg/kg BW could adversely affecting the health and wellbeing of treated animals.
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Affiliation(s)
- Teik Kee Leo
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang 43400, Malaysia; (T.K.L.); (S.G.); (A.Q.S.); (Y.M.G.)
| | - Sani Garba
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang 43400, Malaysia; (T.K.L.); (S.G.); (A.Q.S.); (Y.M.G.)
| | - Danmaigoro Abubakar
- Faculty of Veterinary Medicine, Universiti Putra Malaysia, Serdang 43400, Malaysia;
| | - Awis Qurni Sazili
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang 43400, Malaysia; (T.K.L.); (S.G.); (A.Q.S.); (Y.M.G.)
- Faculty of Agriculture, Universiti Putra Malaysia, Serdang 43400, Malaysia
| | - Su Chui Len Candyrine
- Faculty of Sustainable Agriculture, Universiti Malaysia Sabah, Sandakan 90000, Malaysia;
| | | | - Yong Meng Goh
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang 43400, Malaysia; (T.K.L.); (S.G.); (A.Q.S.); (Y.M.G.)
- Faculty of Veterinary Medicine, Universiti Putra Malaysia, Serdang 43400, Malaysia;
| | - Ron Ronimus
- Rumen Microbiology, AgResearch, Palmerston North 4442, New Zealand; (R.R.); (S.M.)
| | - Stefan Muetzel
- Rumen Microbiology, AgResearch, Palmerston North 4442, New Zealand; (R.R.); (S.M.)
| | - Juan Boo Liang
- Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang 43400, Malaysia; (T.K.L.); (S.G.); (A.Q.S.); (Y.M.G.)
- Correspondence:
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Insolia V, Priori EC, Gasperini C, Coppa F, Cocchia M, Iervasi E, Ferrari B, Besio R, Maruelli S, Bernocchi G, Forlino A, Bottone MG. Prolidase enzyme is required for extracellular matrix integrity and impacts on postnatal cerebellar cortex development. J Comp Neurol 2019; 528:61-80. [PMID: 31246278 DOI: 10.1002/cne.24735] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 06/11/2019] [Accepted: 06/20/2019] [Indexed: 12/12/2022]
Abstract
The extracellular matrix is essential for brain development, lamination, and synaptogenesis. In particular, the basement membrane below the pial meninx (pBM) is required for correct cortical development. The last step in the catabolism of the most abundant protein in pBM, collagen Type IV, requires prolidase, an exopeptidase cleaving the imidodipeptides containing pro or hyp at the C-terminal end. Mutations impairing prolidase activity lead in humans to the rare disease prolidase deficiency characterized by severe skin ulcers and mental impairment. Thus, the dark-like (dal) mouse, in which the prolidase is knocked-out, was used to investigate whether the deficiency of prolidase affects the neuronal maturation during development of a brain cortex area. Focusing on the cerebellar cortex, thinner collagen fibers and disorganized pBM were found. Aberrant cortical granule cell proliferation and migration occurred, associated to defects in brain lamination, and in particular in maturation of Purkinje neurons and formation of synaptic contacts. This study deeply elucidates a link between prolidase activity and neuronal maturation shedding new light on the molecular basis of functional aspects in the prolidase deficiency.
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Affiliation(s)
- Violetta Insolia
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Erica C Priori
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Caterina Gasperini
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Federica Coppa
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Marco Cocchia
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Erika Iervasi
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Beatrice Ferrari
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Roberta Besio
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy
| | - Silvia Maruelli
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy
| | | | - Antonella Forlino
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy
| | - Maria G Bottone
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
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Hakanen J, Ruiz-Reig N, Tissir F. Linking Cell Polarity to Cortical Development and Malformations. Front Cell Neurosci 2019; 13:244. [PMID: 31213986 PMCID: PMC6558068 DOI: 10.3389/fncel.2019.00244] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/16/2019] [Indexed: 01/23/2023] Open
Abstract
Cell polarity refers to the asymmetric distribution of signaling molecules, cellular organelles, and cytoskeleton in a cell. Neural progenitors and neurons are highly polarized cells in which the cell membrane and cytoplasmic components are compartmentalized into distinct functional domains in response to internal and external cues that coordinate polarity and behavior during development and disease. In neural progenitor cells, polarity has a prominent impact on cell shape and coordinate several processes such as adhesion, division, and fate determination. Polarity also accompanies a neuron from the beginning until the end of its life. It is essential for development and later functionality of neuronal circuitries. During development, polarity governs transitions between multipolar and bipolar during migration of postmitotic neurons, and directs the specification and directional growth of axons. Once reaching final positions in cortical layers, neurons form dendrites which become compartmentalized to ensure proper establishment of neuronal connections and signaling. Changes in neuronal polarity induce signaling cascades that regulate cytoskeletal changes, as well as mRNA, protein, and vesicle trafficking, required for synapses to form and function. Hence, defects in establishing and maintaining cell polarity are associated with several neural disorders such as microcephaly, lissencephaly, schizophrenia, autism, and epilepsy. In this review we summarize the role of polarity genes in cortical development and emphasize the relationship between polarity dysfunctions and cortical malformations.
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Affiliation(s)
- Janne Hakanen
- Université catholique de Louvain, Institute of Neuroscience, Developmental Neurobiology, Brussels, Belgium
| | - Nuria Ruiz-Reig
- Université catholique de Louvain, Institute of Neuroscience, Developmental Neurobiology, Brussels, Belgium
| | - Fadel Tissir
- Université catholique de Louvain, Institute of Neuroscience, Developmental Neurobiology, Brussels, Belgium
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Abstract
Proper neuronal wiring is central to all bodily functions, sensory perception, cognition, memory, and learning. Establishment of a functional neuronal circuit is a highly regulated and dynamic process involving axonal and dendritic branching and navigation toward appropriate targets and connection partners. This intricate circuitry includes axo-dendritic synapse formation, synaptic connections formed with effector cells, and extensive dendritic arborization that function to receive and transmit mechanical and chemical sensory inputs. Such complexity is primarily achieved by extensive axonal and dendritic branch formation and pruning. Fundamental to neuronal branching are cytoskeletal dynamics and plasma membrane expansion, both of which are regulated via numerous extracellular and intracellular signaling mechanisms and molecules. This review focuses on recent advances in understanding the biology of neuronal branching.
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Affiliation(s)
- Shalini Menon
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Stephanie Gupton
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, Chapel Hill, NC, 27599, USA.,Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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Reciprocal F1 Hybrids of Two Inbred Mouse Strains Reveal Parent-of-Origin and Perinatal Diet Effects on Behavior and Expression. G3-GENES GENOMES GENETICS 2018; 8:3447-3468. [PMID: 30171036 PMCID: PMC6222572 DOI: 10.1534/g3.118.200135] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Parent-of-origin effects (POE) in mammals typically arise from maternal effects or imprinting. In some instances, such POE have been associated with psychiatric disorders, as well as with changes in a handful of animal behaviors. However, POE on complex traits such as behavior remain largely uncharacterized. Moreover, although both behavior and epigenetic effects are known to be modified by perinatal environmental exposures such as nutrient deficiency, the architecture of such environment-by-POE is mostly unexplored. To study POE and environment-by-POE, we employ a relatively neglected but especially powerful experimental system for POE-detection: reciprocal F1 hybrids (RF1s). We exposed female NOD/ShiLtJ×C57Bl/6J and C57Bl/6J×NOD/ShiLtJ mice, perinatally, to one of four different diets, then after weaning recorded a set of behaviors that model psychiatric disease. Whole-brain microarray expression data revealed an imprinting-enriched set of 15 genes subject to POE. The most-significant expression POE, on the non-imprinted gene Carmil1 (a.k.a. Lrrc16a), was validated using qPCR in the same and in a new set of mice. Several behaviors, especially locomotor behaviors, also showed POE. Bayesian mediation analysis suggested Carmil1 expression suppresses behavioral POE, and that the imprinted gene Airn suppresses POE on Carmil1 expression. A suggestive diet-by-POE was observed on percent center time in the open field test, and a significant diet-by-POE was observed on one imprinted gene, Mir341, and on 16 non-imprinted genes. The relatively small, tractable set of POE and diet-by-POE detected on behavior and expression here motivates further studies examining such effects across RF1s on multiple genetic backgrounds.
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Rich SK, Terman JR. Axon formation, extension, and navigation: only a neuroscience phenomenon? Curr Opin Neurobiol 2018; 53:174-182. [PMID: 30248549 DOI: 10.1016/j.conb.2018.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 08/13/2018] [Indexed: 01/09/2023]
Abstract
Understanding how neurons form, extend, and navigate their finger-like axonal and dendritic processes is crucial for developing therapeutics for the diseased and damaged brain. Although less well appreciated, many other types of cells also send out similar finger-like projections. Indeed, unlike neuronal specific phenomena such as synapse formation or synaptic transmission, an important issue for thought is that this critical long-standing question of how a cellular process like an axon or dendrite forms and extends is not primarily a neuroscience problem but a cell biological problem. In that case, the use of simple cellular processes - such as the bristle cell process of Drosophila - can aid in the fight to answer these critical questions. Specifically, determining how a model cellular process is generated can provide a framework for manipulations of all types of membranous process-containing cells, including different types of neurons.
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Affiliation(s)
- Shannon K Rich
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jonathan R Terman
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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31
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Lasser M, Tiber J, Lowery LA. The Role of the Microtubule Cytoskeleton in Neurodevelopmental Disorders. Front Cell Neurosci 2018; 12:165. [PMID: 29962938 PMCID: PMC6010848 DOI: 10.3389/fncel.2018.00165] [Citation(s) in RCA: 129] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/28/2018] [Indexed: 12/28/2022] Open
Abstract
Neurons depend on the highly dynamic microtubule (MT) cytoskeleton for many different processes during early embryonic development including cell division and migration, intracellular trafficking and signal transduction, as well as proper axon guidance and synapse formation. The coordination and support from MTs is crucial for newly formed neurons to migrate appropriately in order to establish neural connections. Once connections are made, MTs provide structural integrity and support to maintain neural connectivity throughout development. Abnormalities in neural migration and connectivity due to genetic mutations of MT-associated proteins can lead to detrimental developmental defects. Growing evidence suggests that these mutations are associated with many different neurodevelopmental disorders, including intellectual disabilities (ID) and autism spectrum disorders (ASD). In this review article, we highlight the crucial role of the MT cytoskeleton in the context of neurodevelopment and summarize genetic mutations of various MT related proteins that may underlie or contribute to neurodevelopmental disorders.
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Affiliation(s)
- Micaela Lasser
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Jessica Tiber
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Laura Anne Lowery
- Department of Biology, Boston College, Chestnut Hill, MA, United States
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Papandréou MJ, Leterrier C. The functional architecture of axonal actin. Mol Cell Neurosci 2018; 91:151-159. [PMID: 29758267 DOI: 10.1016/j.mcn.2018.05.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 05/10/2018] [Accepted: 05/11/2018] [Indexed: 11/17/2022] Open
Abstract
The cytoskeleton builds and supports the complex architecture of neurons. It orchestrates the specification, growth, and compartmentation of the axon: axon initial segment, axonal shaft, presynapses. The cytoskeleton must then maintain this intricate architecture for the whole life of its host, but also drive its adaptation to new network demands and changing physiological conditions. Microtubules are readily visible inside axon shafts by electron microscopy, whereas axonal actin study has long been focused on dynamic structures of the axon such as growth cones. Super-resolution microscopy and live-cell imaging have recently revealed new actin-based structures in mature axons: rings, hotspots and trails. This has caused renewed interest for axonal actin, with efforts underway to understand the precise organization and cellular functions of these assemblies. Actin is also present in presynapses, where its arrangement is still poorly defined, and its functions vigorously debated. Here we review the organization of axonal actin, focusing on recent advances and current questions in this rejuvenated field.
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Sethi S, Keil KP, Lein PJ. Species and Sex Differences in the Morphogenic Response of Primary Rodent Neurons to 3,3'-Dichlorobiphenyl (PCB 11). TOXICS 2017; 6:toxics6010004. [PMID: 29295518 PMCID: PMC5874777 DOI: 10.3390/toxics6010004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 12/21/2017] [Accepted: 12/21/2017] [Indexed: 12/13/2022]
Abstract
PCB 11 is an emerging global pollutant that we recently showed promotes axonal and dendritic growth in primary rat neuronal cell cultures. Here, we address the influence of sex and species on neuronal responses to PCB 11. Neuronal morphology was quantified in sex-specific primary hippocampal and cortical neuron-glia co-cultures derived from neonatal C57BL/6J mice and Sprague Dawley rats exposed for 48 h to vehicle (0.1% DMSO) or PCB 11 at concentrations ranging from 1 fM to 1 nM. Total axonal length was quantified in tau-1 immunoreactive neurons at day in vitro (DIV) 2; dendritic arborization was assessed by Sholl analysis at DIV 9 in neurons transfected with MAP2B-FusRed. In mouse cultures, PCB 11 enhanced dendritic arborization in female, but not male, hippocampal neurons and male, but not female, cortical neurons. In rat cultures, PCB 11 promoted dendritic arborization in male and female hippocampal and cortical neurons. PCB 11 also increased axonal growth in mouse and rat neurons of both sexes and neuronal cell types. These data demonstrate that PCB 11 exerts sex-specific effects on neuronal morphogenesis that vary depending on species, neurite type, and neuronal cell type. These findings have significant implications for risk assessment of this emerging developmental neurotoxicant.
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Affiliation(s)
- Sunjay Sethi
- Department of Molecular Biosciences, University of California, Davis, CA 95616, USA.
| | - Kimberly P Keil
- Department of Molecular Biosciences, University of California, Davis, CA 95616, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, CA 95616, USA.
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34
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Establishing Neuronal Polarity with Environmental and Intrinsic Mechanisms. Neuron 2017; 96:638-650. [DOI: 10.1016/j.neuron.2017.10.021] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 10/14/2017] [Accepted: 10/15/2017] [Indexed: 12/31/2022]
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35
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Smith GM, Gallo G. The role of mitochondria in axon development and regeneration. Dev Neurobiol 2017; 78:221-237. [PMID: 29030922 DOI: 10.1002/dneu.22546] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/12/2017] [Accepted: 10/08/2017] [Indexed: 12/26/2022]
Abstract
Mitochondria are dynamic organelles that undergo transport, fission, and fusion. The three main functions of mitochondria are to generate ATP, buffer cytosolic calcium, and generate reactive oxygen species. A large body of evidence indicates that mitochondria are either primary targets for neurological disease states and nervous system injury, or are major contributors to the ensuing pathologies. However, the roles of mitochondria in the development and regeneration of axons have just begun to be elucidated. Advances in the understanding of the functional roles of mitochondria in neurons had been largely impeded by insufficient knowledge regarding the molecular mechanisms that regulate mitochondrial transport, stalling, fission/fusion, and a paucity of approaches to image and analyze mitochondria in living axons at the level of the single mitochondrion. However, technical advances in the imaging and analysis of mitochondria in living neurons and significant insights into the mechanisms that regulate mitochondrial dynamics have allowed the field to advance. Mitochondria have now been attributed important roles in the mechanism of axon extension, regeneration, and axon branching. The availability of new experimental tools is expected to rapidly increase our understanding of the functions of axonal mitochondria during both development and later regenerative attempts. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 221-237, 2018.
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Affiliation(s)
- George M Smith
- Department of Neuroscience, Temple University, Lewis Katz School of Medicine, Philadelphia, Pennsylvania, 19140.,Shriners Hospitals Pediatric Research Center, Temple University, Lewis Katz School of Medicine, Philadelphia, Pennsylvania, 19140
| | - Gianluca Gallo
- Department of Anatomy and Cell Biology, Temple University, Lewis Katz School of Medicine, Philadelphia, Pennsylvania, 19140.,Shriners Hospitals Pediatric Research Center, Temple University, Lewis Katz School of Medicine, Philadelphia, Pennsylvania, 19140
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Trim9 Deletion Alters the Morphogenesis of Developing and Adult-Born Hippocampal Neurons and Impairs Spatial Learning and Memory. J Neurosci 2017; 36:4940-58. [PMID: 27147649 DOI: 10.1523/jneurosci.3876-15.2016] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 03/07/2016] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED During hippocampal development, newly born neurons migrate to appropriate destinations, extend axons, and ramify dendritic arbors to establish functional circuitry. These developmental stages are recapitulated in the dentate gyrus of the adult hippocampus, where neurons are continuously generated and subsequently incorporate into existing, local circuitry. Here we demonstrate that the E3 ubiquitin ligase TRIM9 regulates these developmental stages in embryonic and adult-born mouse hippocampal neurons in vitro and in vivo Embryonic hippocampal and adult-born dentate granule neurons lacking Trim9 exhibit several morphological defects, including excessive dendritic arborization. Although gross anatomy of the hippocampus was not detectably altered by Trim9 deletion, a significant number of Trim9(-/-) adult-born dentate neurons localized inappropriately. These morphological and localization defects of hippocampal neurons in Trim9(-/-) mice were associated with extreme deficits in spatial learning and memory, suggesting that TRIM9-directed neuronal morphogenesis may be involved in hippocampal-dependent behaviors. SIGNIFICANCE STATEMENT Appropriate generation and incorporation of adult-born neurons in the dentate gyrus are critical for spatial learning and memory and other hippocampal functions. Here we identify the brain-enriched E3 ubiquitin ligase TRIM9 as a novel regulator of embryonic and adult hippocampal neuron shape acquisition and hippocampal-dependent behaviors. Genetic deletion of Trim9 elevated dendritic arborization of hippocampal neurons in vitro and in vivo Adult-born dentate granule cells lacking Trim9 similarly exhibited excessive dendritic arborization and mislocalization of cell bodies in vivo These cellular defects were associated with severe deficits in spatial learning and memory.
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Liu Y, Xu YF, Zhang L, Huang L, Yu P, Zhu H, Deng W, Qin C. Effective expression of Drebrin in hippocampus improves cognitive function and alleviates lesions of Alzheimer's disease in APP (swe)/PS1 (ΔE9) mice. CNS Neurosci Ther 2017; 23:590-604. [PMID: 28597477 DOI: 10.1111/cns.12706] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 04/18/2017] [Accepted: 04/18/2017] [Indexed: 02/06/2023] Open
Abstract
AIMS Alzheimer's disease (AD), a progressive development dementia, is increasingly impacting patients' living conditions worldwide. Despite medical care and funding support, there are still no highly individualized drugs and practical strategies for clinical prevention and treatment. Developmentally regulated brain protein (abbreviated as Drebrin or Dbn, also known as Dbn1 in mouse) exists in neurons, especially in dendrites, and is an actin-binding protein that modulates synaptic morphology and long-term memory. However, the majority of previous studies have focused on its upstream proteins and neglected the impact Drebrin has on behavior and AD in vivo. METHODS Here, we tracked the behavioral performances of 4-, 8-, 12-, and 16-month-old AD mice and investigated the expression level of Drebrin in their hippocampi. A Pearson correlation analysis between Drebrin levels and behavioral data was performed. Subsequently, 2-month-old AD mice were injected with rAAV-zsGreen-Dbn1 vector, composing the APP/PS1-Dbn1 group, and sex- and age-matched AD mice were injected with rAAV-tdTomato vector to serve as the control group. All mice were conducted behavioral tests and molecular detection 6 months later. RESULTS (i) The expression of Drebrin is decreased in the hippocampus of aged AD mice compared with that of age-matched WT and young adult AD mice; (ii) cognitive ability of APP/PS1 mice decreases with age; (iii) Drebrin protein expression in the hippocampus correlates with behavioral performance in different aged AD mice; (iv) cognitive ability improved significantly in APP/PS1-Dbn1 mice; (v) the expression level of Drebrin in APP/PS1-Dbn1 mouse hippocampus was significantly increased; (vi) the pathological lesion of AD was alleviated in APP/PS1-Dbn1 mice; (vii) the filamentous actin (F-actin) and microtubule-associated protein 2(MAP-2) in APP/PS1-Dbn1 mice were notably more than control mice. CONCLUSION In this study, an effective expression of Drebrin improves cognitive abilities and alleviates lesions in an AD mouse model. These results may provide some valid resources for therapy and research of AD.
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Affiliation(s)
- Yan Liu
- Comparative Medicine Centre, Peking Union Medical College (PUMC) and Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS), Beijing, China
| | - Yan-Feng Xu
- Comparative Medicine Centre, Peking Union Medical College (PUMC) and Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS), Beijing, China
| | - Ling Zhang
- Comparative Medicine Centre, Peking Union Medical College (PUMC) and Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS), Beijing, China
| | - Lan Huang
- Comparative Medicine Centre, Peking Union Medical College (PUMC) and Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS), Beijing, China
| | - Pin Yu
- Comparative Medicine Centre, Peking Union Medical College (PUMC) and Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS), Beijing, China
| | - Hua Zhu
- Comparative Medicine Centre, Peking Union Medical College (PUMC) and Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS), Beijing, China
| | - Wei Deng
- Comparative Medicine Centre, Peking Union Medical College (PUMC) and Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS), Beijing, China
| | - Chuan Qin
- Comparative Medicine Centre, Peking Union Medical College (PUMC) and Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS), Beijing, China
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McNeely KC, Cupp TD, Little JN, Janisch KM, Shrestha A, Dwyer ND. Mutation of Kinesin-6 Kif20b causes defects in cortical neuron polarization and morphogenesis. Neural Dev 2017; 12:5. [PMID: 28359322 PMCID: PMC5374676 DOI: 10.1186/s13064-017-0082-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 03/22/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND How neurons change their cytoskeleton to adopt their complex polarized morphology is still not understood. Growing evidence suggests that proteins that help build microtubule structures during cell division are also involved in building and remodeling the complex cytoskeletons of neurons. Kif20b (previously called MPP1 or Mphosph1) is the most divergent member of the Kinesin-6 family of "mitotic" kinesins that also includes Kif23/MKLP1 and Kif20a/MKLP2. We previously isolated a loss-of-function mouse mutant of Kif20b and showed that it had a thalamocortical axon guidance defect and microcephaly. METHODS We demonstrate here, using the mouse mutant, that Kif20b is required for neuron morphogenesis in the embryonic neocortex. In vivo and in vitro cortical neurons were labeled and imaged to analyze various aspects of morphogenesis. RESULTS Loss of Kif20b disrupts polarization as well as neurite outgrowth, branching and caliber. In vivo, mutant cortical neurons show defects in orientation, and have shorter thinner apical dendrites that branch closer to the cell body. In vitro, without external polarity cues, Kif20b mutant neurons show a strong polarization defect. This may be due in part to loss of the polarity protein Shootin1 from the axonal growth cone. Those mutant neurons that do succeed in polarizing have shorter axons with more branches, and longer minor neurites. These changes in shape are not due to alterations in cell fate or neuron layer type. Surprisingly, both axons and minor neurites of mutant neurons have increased widths and longer growth cone filopodia, which correlate with abnormal microtubule organization. Live analysis of axon extension shows that Kif20b mutant axons display more variable growth with increased retraction. CONCLUSIONS These results demonstrate that Kif20b is required cell-autonomously for proper morphogenesis of cortical pyramidal neurons. Kif20b regulates neuron polarization, and axon and dendrite branching, outgrowth, and caliber. Kif20b protein may act by bundling microtubules into tight arrays and by localizing effectors such as Shootin1. Thus it may help shape neurites, sustain consistent axon growth, and inhibit branching. This work advances our understanding of how neurons regulate their cytoskeleton to build their elaborate shapes. Finally, it suggests that neuronal connectivity defects may be present in some types of microcephaly.
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Affiliation(s)
- Katrina C McNeely
- Department of Cell Biology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Timothy D Cupp
- Department of Cell Biology, University of Virginia, Charlottesville, VA, 22908, USA
| | | | - Kerstin M Janisch
- Department of Cell Biology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Ayushma Shrestha
- Department of Cell Biology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Noelle D Dwyer
- Department of Cell Biology, University of Virginia, Charlottesville, VA, 22908, USA.
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Wilson MD, Sethi S, Lein PJ, Keil KP. Valid statistical approaches for analyzing sholl data: Mixed effects versus simple linear models. J Neurosci Methods 2017; 279:33-43. [PMID: 28104486 PMCID: PMC5346342 DOI: 10.1016/j.jneumeth.2017.01.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 01/27/2023]
Abstract
BACKGROUND The Sholl technique is widely used to quantify dendritic morphology. Data from such studies, which typically sample multiple neurons per animal, are often analyzed using simple linear models. However, simple linear models fail to account for intra-class correlation that occurs with clustered data, which can lead to faulty inferences. NEW METHOD Mixed effects models account for intra-class correlation that occurs with clustered data; thus, these models more accurately estimate the standard deviation of the parameter estimate, which produces more accurate p-values. While mixed models are not new, their use in neuroscience has lagged behind their use in other disciplines. RESULTS A review of the published literature illustrates common mistakes in analyses of Sholl data. Analysis of Sholl data collected from Golgi-stained pyramidal neurons in the hippocampus of male and female mice using both simple linear and mixed effects models demonstrates that the p-values and standard deviations obtained using the simple linear models are biased downwards and lead to erroneous rejection of the null hypothesis in some analyses. COMPARISON WITH EXISTING METHODS The mixed effects approach more accurately models the true variability in the data set, which leads to correct inference. CONCLUSIONS Mixed effects models avoid faulty inference in Sholl analysis of data sampled from multiple neurons per animal by accounting for intra-class correlation. Given the widespread practice in neuroscience of obtaining multiple measurements per subject, there is a critical need to apply mixed effects models more widely.
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Affiliation(s)
- Machelle D Wilson
- Clinical and Translational Science Center, Department of Public Health Sciences, Division of Biostatistics, University of California, Davis, CA, United States
| | - Sunjay Sethi
- Department of Molecular Biosciences, University of California, Davis, CA, United States
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, CA, United States
| | - Kimberly P Keil
- Department of Molecular Biosciences, University of California, Davis, CA, United States.
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Zhao Y, Yu Y, Zhang Y, He L, Qiu L, Zhao J, Liu M, Zhang J. Letrozole regulates actin cytoskeleton polymerization dynamics in a SRC-1 dependent manner in the hippocampus of mice. J Steroid Biochem Mol Biol 2017; 167:86-97. [PMID: 27866972 DOI: 10.1016/j.jsbmb.2016.11.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 10/24/2016] [Accepted: 11/16/2016] [Indexed: 12/21/2022]
Abstract
In the hippocampus, local estrogens (E2) derived from testosterone that is catalyzed by aromatase play important roles in the regulation of hippocampal neural plasticity, but the underlying mechanisms remain unclear. The actin cytoskeleton contributes greatly to hippocampal synaptic plasticity; however, whether it is regulated by local E2 and the related mechanisms remain to be elucidated. In this study, we first examined the postnatal developmental profiles of hippocampal aromatase and specific proteins responsible for actin cytoskeleton dynamics. Then we used aromatase inhibitor letrozole (LET) to block local E2 synthesis and examined the changes of these proteins and steroid receptor coactivator-1 (SRC-1), the predominant coactivator for steroid nuclear receptors. Finally, SRC-1 specific RNA interference was used to examine the effects of SRC-1 on the expression of these actin remodeling proteins. The results showed a V-type profile for aromatase and increased profiles for actin cytoskeleton proteins in both male and female hippocampus without obvious sex differences. LET treatment dramatically decreased the F-actin/G-actin ratio, the expression of Rictor, phospho-AKT (ser473), Profilin-1, phospho-Cofilin (Ser3), and SRC-1 in a dose-dependent manner. In vitro studies demonstrated that LET induced downregulation of these proteins could be reversed by E2, and E2 induced increase of these proteins were significantly suppressed by SRC-1 shRNA interference. These results for the first time clearly demonstrated that local E2 inhibition could induce aberrant actin polymerization; they also showed an important role of SRC-1 in the mediation of local E2 action on hippocampal synaptic plasticity by regulation of actin cytoskeleton dynamics.
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Affiliation(s)
- Yangang Zhao
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Yanlan Yu
- Student Brigade, Third Military Medical University, Chongqing 400038, China
| | - Yuanyuan Zhang
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Li He
- School of Nursing, Third Military Medical University, Chongqing 400038, China
| | - Linli Qiu
- School of Nursing, Third Military Medical University, Chongqing 400038, China; Department of Nursing, Sichuan Nursing Vocational College, Chengdu 610100, China
| | - Jikai Zhao
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Mengying Liu
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
| | - Jiqiang Zhang
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China.
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Segura-Uribe JJ, Pinto-Almazán R, Coyoy-Salgado A, Fuentes-Venado CE, Guerra-Araiza C. Effects of estrogen receptor modulators on cytoskeletal proteins in the central nervous system. Neural Regen Res 2017; 12:1231-1240. [PMID: 28966632 PMCID: PMC5607812 DOI: 10.4103/1673-5374.213536] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Estrogen receptor modulators are compounds of interest because of their estrogenic agonistic/antagonistic effects and tissue specificity. These compounds have many clinical applications, particularly for breast cancer treatment and osteoporosis in postmenopausal women, as well as for the treatment of climacteric symptoms. Similar to estrogens, neuroprotective effects of estrogen receptor modulators have been described in different models. However, the mechanisms of action of these compounds in the central nervous system have not been fully described. We conducted a systematic search to investigate the effects of estrogen receptor modulators in the central nervous system, focusing on the modulation of cytoskeletal proteins. We found that raloxifene, tamoxifen, and tibolone modulate some cytoskeletal proteins such as tau, microtuble-associated protein 1 (MAP1), MAP2, neurofilament 38 (NF38) by different mechanisms of action and at different levels: neuronal microfilaments, intermediate filaments, and microtubule-associated proteins. Finally, we emphasize the importance of the study of these compounds in the treatment of neurodegenerative diseases since they present the benefits of estrogens without their side effects.
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Affiliation(s)
- Julia J Segura-Uribe
- Unidad de Investigación Médica en Enfermedades Neurológicas, Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico.,Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Rodolfo Pinto-Almazán
- Unidad de Investigación Hospital Regional de Alta Especialidad Ixtapaluca, Ixtapaluca, Mexico.,Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, CA, USA.,Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Angélica Coyoy-Salgado
- Unidad de Investigación Médica en Enfermedades Neurológicas, Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico.,Consejo Nacional de Ciencia y Tecnología, Mexico City, Mexico
| | - Claudia E Fuentes-Venado
- Clínica de Trastornos del Sueño, Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Mexico.,Servicio de Medicina Física y Rehabilitacion, Hospital General de Zona No. 197, Texcoco, Mexico.,Unidad de Investigación Médica en Farmacología, Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Christian Guerra-Araiza
- Unidad de Investigación Médica en Farmacología, Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
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