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Kraus JEM, Busengdal H, Kraus Y, Hausen H, Rentzsch F. Doublecortin-like kinase is required for cnidocyte development in Nematostella vectensis. Neural Dev 2024; 19:11. [PMID: 38909268 PMCID: PMC11193195 DOI: 10.1186/s13064-024-00188-0] [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: 01/30/2024] [Accepted: 06/15/2024] [Indexed: 06/24/2024] Open
Abstract
The complex morphology of neurons requires precise control of their microtubule cytoskeleton. This is achieved by microtubule-associated proteins (MAPs) that regulate the assembly and stability of microtubules, and transport of molecules and vesicles along them. While many of these MAPs function in all cells, some are specifically or predominantly involved in regulating microtubules in neurons. Here we use the sea anemone Nematostella vectensis as a model organism to provide new insights into the early evolution of neural microtubule regulation. As a cnidarian, Nematostella belongs to an outgroup to all bilaterians and thus occupies an informative phylogenetic position for reconstructing the evolution of nervous system development. We identified an ortholog of the microtubule-binding protein doublecortin-like kinase (NvDclk1) as a gene that is predominantly expressed in neurons and cnidocytes (stinging cells), two classes of cells belonging to the neural lineage in cnidarians. A transgenic NvDclk1 reporter line revealed an elaborate network of neurite-like processes emerging from cnidocytes in the tentacles and the body column. A transgene expressing NvDclk1 under the control of the NvDclk1 promoter suggests that NvDclk1 localizes to microtubules and therefore likely functions as a microtubule-binding protein. Further, we generated a mutant for NvDclk1 using CRISPR/Cas9 and show that the mutants fail to generate mature cnidocytes. Our results support the hypothesis that the elaboration of programs for microtubule regulation occurred early in the evolution of nervous systems.
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Affiliation(s)
- Johanna E M Kraus
- Michael Sars Centre, University of Bergen, Thormøhlensgt 55, Bergen, 5006, Norway
| | - Henriette Busengdal
- Michael Sars Centre, University of Bergen, Thormøhlensgt 55, Bergen, 5006, Norway
| | - Yulia Kraus
- Department of Evolutionary Biology, Biological Faculty, Moscow State University, Leninskiye gory 1/12, Moscow, 119234, Russia
| | - Harald Hausen
- Michael Sars Centre, University of Bergen, Thormøhlensgt 55, Bergen, 5006, Norway
- Department of Earth Science, University of Bergen, Allégaten 41, Bergen, 5007, Norway
| | - Fabian Rentzsch
- Michael Sars Centre, University of Bergen, Thormøhlensgt 55, Bergen, 5006, Norway.
- Department for Biological Sciences, University of Bergen, Thormøhlensgate 53, Bergen, 5006, Norway.
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2
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Altered genome-wide hippocampal gene expression profiles following early life lead exposure and their potential for reversal by environmental enrichment. Sci Rep 2022; 12:11937. [PMID: 35879375 PMCID: PMC9314447 DOI: 10.1038/s41598-022-15861-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 06/30/2022] [Indexed: 12/02/2022] Open
Abstract
Early life lead (Pb) exposure is detrimental to neurobehavioral development. The quality of the environment can modify negative influences from Pb exposure, impacting the developmental trajectory following Pb exposure. Little is known about the molecular underpinnings in the brain of the interaction between Pb and the quality of the environment. We examined relationships between early life Pb exposure and living in an enriched versus a non-enriched postnatal environment on genome-wide transcription profiles in hippocampus CA1. RNA-seq identified differences in the transcriptome of enriched vs. non-enriched Pb-exposed animals. Most of the gene expression changes associated with Pb exposure were reversed by enrichment. This was also true for changes in upstream regulators, splicing events and long noncoding RNAs. Non-enriched rats also had memory impairments; enriched rats had no deficits. The results demonstrate that an enriched environment has a profound impact on behavior and the Pb-modified CA1 transcriptome. These findings show the potential for interactions between Pb exposure and the environment to result in significant transcriptional changes in the brain and, to the extent that this may occur in Pb-exposed children, could influence neuropsychological/educational outcomes, underscoring the importance for early intervention and environmental enrichment for Pb-exposed children.
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3
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Scala M, Nishikawa M, Nagata KI, Striano P. Pathophysiological Mechanisms in Neurodevelopmental Disorders Caused by Rac GTPases Dysregulation: What's behind Neuro-RACopathies. Cells 2021; 10:3395. [PMID: 34943902 PMCID: PMC8699292 DOI: 10.3390/cells10123395] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/23/2021] [Accepted: 11/30/2021] [Indexed: 02/07/2023] Open
Abstract
Rho family guanosine triphosphatases (GTPases) regulate cellular signaling and cytoskeletal dynamics, playing a pivotal role in cell adhesion, migration, and cell cycle progression. The Rac subfamily of Rho GTPases consists of three highly homologous proteins, Rac 1-3. The proper function of Rac1 and Rac3, and their correct interaction with guanine nucleotide-exchange factors (GEFs) and GTPase-activating proteins (GAPs) are crucial for neural development. Pathogenic variants affecting these delicate biological processes are implicated in different medical conditions in humans, primarily neurodevelopmental disorders (NDDs). In addition to a direct deleterious effect produced by genetic variants in the RAC genes, a dysregulated GTPase activity resulting from an abnormal function of GEFs and GAPs has been involved in the pathogenesis of distinctive emerging conditions. In this study, we reviewed the current pertinent literature on Rac-related disorders with a primary neurological involvement, providing an overview of the current knowledge on the pathophysiological mechanisms involved in the neuro-RACopathies.
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Affiliation(s)
- Marcello Scala
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16132 Genoa, Italy;
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Masashi Nishikawa
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai 480-0392, Japan; (M.N.); (K.-i.N.)
| | - Koh-ichi Nagata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai 480-0392, Japan; (M.N.); (K.-i.N.)
- Department of Neurochemistry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Nagoya 466-8550, Japan
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16132 Genoa, Italy;
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
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Roy A, Kundu M, Chakrabarti S, Patel DR, Pahan K. Oleamide, a Sleep-Inducing Supplement, Upregulates Doublecortin in Hippocampal Progenitor Cells via PPARα. J Alzheimers Dis 2021; 84:1747-1762. [PMID: 34744082 PMCID: PMC10075226 DOI: 10.3233/jad-215124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Doublecortin (DCX), a microtubule associated protein, has emerged as a central biomarker of hippocampal neurogenesis. However, molecular mechanisms by which DCX is regulated are poorly understood. OBJECTIVE Since sleep is involved with the acquisition of memory and oleamide or 9-Octadecenamide (OCT) is a sleep-inducing supplement in human, we examined whether OCT could upregulate DCX in hippocampal progenitor cells (HPCs). METHODS We employed real-time PCR, western blot, immunostaining, chromatin immunoprecipitation, lentiviral transduction in HPCs, and the calcium influx assay. RESULTS OCT directly upregulated the transcription of Dcx in HPCs via activation of peroxisome proliferator-activated receptor α (PPARα), a lipid-lowering transcription factor. We observed that, HPCs of Ppara-null mice displayed significant impairment in DCX expression and neuronal differentiation as compared to that of wild-type mice. Interestingly, treatment with OCT stimulated the differentiation process of HPCs in wild-type, but not Ppara-null mice. Reconstruction of PPARα in mouse Ppara-null HPCs restored the expression of DCX, which was further stimulated with OCT treatment. In contrast, a dominant-negative mutant of PPARα significantly attenuated the stimulatory effect of OCT on DCX expression and suppressed neuronal differentiation of human neural progenitor cells. Furthermore, RNA microarray, STRING, chromatin immunoprecipitation, site-directed mutagenesis, and promoter reporter assay have identified DCX as a new target of PPARα. CONCLUSION These results indicate that OCT, a sleep supplement, directly controls the expression of DCX and suggest that OCT may be repurposed for stimulating the hippocampal neurogenesis.
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Affiliation(s)
- Avik Roy
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Madhuchhanda Kundu
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Sudipta Chakrabarti
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Dhruv R Patel
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Kalipada Pahan
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA.,Division of Research and Development, Jesse Brown Veterans Affairs Medical Center, Chicago, IL, USA
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Karoglu-Eravsar ET, Tuz-Sasik MU, Adams MM. Short-term dietary restriction maintains synaptic plasticity whereas short-term overfeeding alters cellular dynamics in the aged brain: evidence from the zebrafish model organism. Neurobiol Aging 2021; 106:169-182. [PMID: 34284260 DOI: 10.1016/j.neurobiolaging.2021.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 05/06/2021] [Accepted: 06/12/2021] [Indexed: 12/12/2022]
Abstract
Increased caloric intake (OF) impairs quality of life causing comorbidities with other diseases and cognitive deficits, whereas dietary restriction (DR) increases healthspan by preventing age-related deteriorations. To understand the effects of these opposing dietary regimens on the cellular and synaptic dynamics during brain aging, the zebrafish model, which shows gradual aging like mammals, was utilized. Global changes in cellular and synaptic markers with respect to age and a 12 week dietary regimen of OF and DR demonstrated that aging reduces the levels of the glutamate receptor subunits, GLUR2/3, inhibitory synaptic clustering protein, GEP, synaptic vesicle protein, SYP, and early-differentiated neuronal marker, HuC. DR significantly elevates levels of glutamate receptor subunits, GLUR2/3, and NMDA clustering protein, PSD95, levels, while OF subtly increases the level of the neuronal protein, DCAMKL1. These data suggest that decreased caloric intake within the context of aging has more robust effects on synapses than cellular proteins, whereas OF alters cellular dynamics. Thus, patterns like these should be taken into account for possible translation to human subjects.
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Affiliation(s)
- Elif Tugce Karoglu-Eravsar
- Interdisciplinary Program in Neuroscience, Aysel Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey; National Nanotechnology Research Center (UNAM), Bilkent University, Ankara, Turkey; Department of Molecular Biology and Genetics, Zebrafish Facility, Bilkent University, Ankara, Turkey; Department of Psychology, Selcuk University, Konya, Turkey
| | - Melek Umay Tuz-Sasik
- Interdisciplinary Program in Neuroscience, Aysel Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey; National Nanotechnology Research Center (UNAM), Bilkent University, Ankara, Turkey; Department of Molecular Biology and Genetics, Zebrafish Facility, Bilkent University, Ankara, Turkey
| | - Michelle M Adams
- Interdisciplinary Program in Neuroscience, Aysel Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey; National Nanotechnology Research Center (UNAM), Bilkent University, Ankara, Turkey; Department of Molecular Biology and Genetics, Zebrafish Facility, Bilkent University, Ankara, Turkey; Department of Psychology, Bilkent University, Ankara, Turkey.
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6
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Song J, Merrill RA, Usachev AY, Strack S. The X-linked intellectual disability gene product and E3 ubiquitin ligase KLHL15 degrades doublecortin proteins to constrain neuronal dendritogenesis. J Biol Chem 2020; 296:100082. [PMID: 33199366 PMCID: PMC7948412 DOI: 10.1074/jbc.ra120.016210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/27/2020] [Accepted: 11/16/2020] [Indexed: 11/13/2022] Open
Abstract
Proper brain development and function requires finely controlled mechanisms for protein turnover, and disruption of genes involved in proteostasis is a common cause of neurodevelopmental disorders. Kelch-like 15 (KLHL15) is a substrate adaptor for cullin3-containing E3 ubiquitin ligases, and KLHL15 gene mutations were recently described as a cause of severe X-linked intellectual disability. Here, we used a bioinformatics approach to identify a family of neuronal microtubule-associated proteins as KLHL15 substrates, which are themselves critical for early brain development. We biochemically validated doublecortin (DCX), also an X-linked disease protein, and doublecortin-like kinase 1 and 2 as bona fide KLHL15 interactors and mapped KLHL15 interaction regions to their tandem DCX domains. Shared with two previously identified KLHL15 substrates, a FRY tripeptide at the C-terminal edge of the second DCX domain is necessary for KLHL15-mediated ubiquitination of DCX and doublecortin-like kinase 1 and 2 and subsequent proteasomal degradation. Conversely, silencing endogenous KLHL15 markedly stabilizes these DCX domain-containing proteins and prolongs their half-life. Functionally, overexpression of KLHL15 in the presence of WT DCX reduces dendritic complexity of cultured hippocampal neurons, whereas neurons expressing FRY-mutant DCX are resistant to KLHL15. Collectively, our findings highlight the critical importance of the E3 ubiquitin ligase adaptor KLHL15 in proteostasis of neuronal microtubule-associated proteins and identify a regulatory network important for development of the mammalian nervous system.
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Affiliation(s)
- Jianing Song
- Department of Neuroscience and Pharmacology and the Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA
| | - Ronald A Merrill
- Department of Neuroscience and Pharmacology and the Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA
| | - Andrew Y Usachev
- Department of Neuroscience and Pharmacology and the Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology and the Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA.
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7
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Doublecortin-Like Is Implicated in Adult Hippocampal Neurogenesis and in Motivational Aspects to Escape from an Aversive Environment in Male Mice. eNeuro 2020; 7:ENEURO.0324-19.2020. [PMID: 32994174 PMCID: PMC7568604 DOI: 10.1523/eneuro.0324-19.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 08/12/2020] [Accepted: 08/14/2020] [Indexed: 12/02/2022] Open
Abstract
Doublecortin (DCX)-like (DCL) is a microtubule (MT)-associated protein (MAP) that is highly homologous to DCX and is crucially involved in embryonic neurogenesis. Here, we have investigated the in vivo role of DCL in adult hippocampal neurogenesis by generating transgenic mice producing inducible shRNA molecules that specifically target DCL but no other splice variants produced by the DCLK gene. DCL knock-down (DCL-KD) resulted in a significant increase in the number of proliferating BrdU+ cells in the subgranular zone (SGZ) 1 d after BrdU administration. However, the number of surviving newborn adult NeuN+/BrdU+ neurons are significantly decreased when inspected four weeks after BrdU administration suggesting a blockade of neuronal differentiation after DCL-KD. In line with this, we observed an increase in the number of proliferating cells, but a significant decrease in postmitotic DCX+ cells that are characterized by long dendrites spanning all dentate gyrus layers. Behavioral analysis showed that DCL-KD strongly extended the escape latency of mice on the circular hole board (CHB) but did not affect other aspects of this behavioral task. Together, our results indicate a function for DCL in adult neurogenesis and in the motivation to escape from an aversive environment. In contrast to DCX, its pivotal role in the maturation of postmitotic neuronal progenitor cells (NPCs) marks DCL as a genuine adult neurogenesis indicator in the hippocampus.
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8
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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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Ramkumar A, Jong BY, Ori-McKenney KM. ReMAPping the microtubule landscape: How phosphorylation dictates the activities of microtubule-associated proteins. Dev Dyn 2017; 247:138-155. [PMID: 28980356 DOI: 10.1002/dvdy.24599] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 09/11/2017] [Accepted: 09/19/2017] [Indexed: 12/12/2022] Open
Abstract
Classical microtubule-associated proteins (MAPs) were originally identified based on their co-purification with microtubules assembled from mammalian brain lysate. They have since been found to perform a range of functions involved in regulating the dynamics of the microtubule cytoskeleton. Most of these MAPs play integral roles in microtubule organization during neuronal development, microtubule remodeling during neuronal activity, and microtubule stabilization during neuronal maintenance. As a result, mutations in MAPs contribute to neurodevelopmental disorders, psychiatric conditions, and neurodegenerative diseases. MAPs are post-translationally regulated by phosphorylation depending on developmental time point and cellular context. Phosphorylation can affect the microtubule affinity, cellular localization, or overall function of a particular MAP and can thus have profound implications for neuronal health. Here we review MAP1, MAP2, MAP4, MAP6, MAP7, MAP9, tau, and DCX, and how each is regulated by phosphorylation in neuronal physiology and disease. Developmental Dynamics 247:138-155, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Amrita Ramkumar
- Department of Molecular and Cellular Biology, University of California, Davis, CA
| | - Brigette Y Jong
- Department of Molecular and Cellular Biology, University of California, Davis, CA
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Katsarou A, Moshé SL, Galanopoulou AS. INTERNEURONOPATHIES AND THEIR ROLE IN EARLY LIFE EPILEPSIES AND NEURODEVELOPMENTAL DISORDERS. Epilepsia Open 2017; 2:284-306. [PMID: 29062978 PMCID: PMC5650248 DOI: 10.1002/epi4.12062] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2017] [Indexed: 12/22/2022] Open
Abstract
GABAergic interneurons control the neural circuitry and network activity in the brain. The advances in genetics have identified genes that control the development, maturation and integration of GABAergic interneurons and implicated them in the pathogenesis of epileptic encephalopathies or neurodevelopmental disorders. For example, mutations of the Aristaless-Related homeobox X-linked gene (ARX) may result in defective GABAergic interneuronal migration in infants with epileptic encephalopathies like West syndrome (WS), Ohtahara syndrome or X-linked lissencephaly with abnormal genitalia (XLAG). The concept of "interneuronopathy", i.e. impaired development, migration or function of interneurons, has emerged as a possible etiopathogenic mechanism for epileptic encephalopathies. Treatments that enhance GABA levels, may help seizure control but do not necessarily show disease modifying effect. On the other hand, interneuronopathies can be seen in other conditions in which epilepsy may not be the primary manifestation, such as autism. In this review, we plan to outline briefly the current state of knowledge on the origin, development, and migration and integration of GABAergic interneurons, present neurodevelopmental conditions, with or without epilepsy, that have been associated with interneuronopathies and discuss the evidence linking certain types of interneuronal dysfunction with epilepsy and/or cognitive or behavioral deficits.
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Affiliation(s)
- Anna‐Maria Katsarou
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Solomon L. Moshé
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Dominick P. Purpura Department of NeuroscienceMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Department of PediatricsAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Aristea S. Galanopoulou
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Dominick P. Purpura Department of NeuroscienceMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
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Yap CC, Digilio L, McMahon L, Roszkowska M, Bott CJ, Kruczek K, Winckler B. Different Doublecortin (DCX) Patient Alleles Show Distinct Phenotypes in Cultured Neurons: EVIDENCE FOR DIVERGENT LOSS-OF-FUNCTION AND "OFF-PATHWAY" CELLULAR MECHANISMS. J Biol Chem 2016; 291:26613-26626. [PMID: 27799303 DOI: 10.1074/jbc.m116.760777] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 10/28/2016] [Indexed: 11/06/2022] Open
Abstract
Doublecortin on the X-chromosome (DCX) is a neuronal microtubule-binding protein with a multitude of roles in neurodevelopment. In humans, DCX is a major genetic locus for X-linked lissencephaly. The best studied defects are in neuronal migration during corticogenesis and in the hippocampus, as well as axon and dendrite growth defects. Much effort has been directed at understanding the molecular and cellular bases of DCX-linked lissencephaly. The focus has been in particular on defects in microtubule assembly and bundling, using knock-out mice and expression of WT and mutant Dcx in non-neuronal cells. Dcx also binds other proteins besides microtubules, such as spinophilin (abbreviated spn; gene name Ppp1r9b protein phosphatase 1 regulatory subunit 9b) and the clathrin adaptors AP-1 and AP-2. Even though many non-sense and missense mutations of Dcx are known, their molecular and cellular defects are still only incompletely understood. It is also largely unknown how neurons are affected by expression of DCX patient alleles. We have now characterized several patient DCX alleles (DCX-R89G, DCX-R59H, DCX-246X, DCX-272X, and DCX-303X) using a gain-of-function dendrite growth assay in cultured rat neurons in combination with the determination of molecular binding activities and subcellular localization in non-neuronal and neuronal cells. First, we find that several mutants (Dcx-R89G and Dcx-272X) were loss-of-function alleles (as had been postulated) but surprisingly acted via different cellular mechanisms. Second, one allele (Dcx-R59H) formed cytoplasmic aggregates, which contained Hspa1B (heat shock protein 1B hsp70) and ubiquitinated proteins, trapped other cytoskeletal proteins, including spinophilin, and led to increased autophagy. This allele could thus be categorized as "off-pathway"/possibly neomorph. Our findings thus suggested that distinct DCX alleles caused dysfunction by different mechanisms.
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Affiliation(s)
- Chan Choo Yap
- From the Department of Cell Biology, University of Virginia, Charlottesville, Virginia 22908
| | - Laura Digilio
- From the Department of Cell Biology, University of Virginia, Charlottesville, Virginia 22908
| | - Lloyd McMahon
- From the Department of Cell Biology, University of Virginia, Charlottesville, Virginia 22908
| | - Matylda Roszkowska
- From the Department of Cell Biology, University of Virginia, Charlottesville, Virginia 22908
| | - Christopher J Bott
- From the Department of Cell Biology, University of Virginia, Charlottesville, Virginia 22908
| | - Kamil Kruczek
- From the Department of Cell Biology, University of Virginia, Charlottesville, Virginia 22908
| | - Bettina Winckler
- From the Department of Cell Biology, University of Virginia, Charlottesville, Virginia 22908
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12
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Moffat JJ, Ka M, Jung EM, Kim WY. Genes and brain malformations associated with abnormal neuron positioning. Mol Brain 2015; 8:72. [PMID: 26541977 PMCID: PMC4635534 DOI: 10.1186/s13041-015-0164-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 10/31/2015] [Indexed: 01/05/2023] Open
Abstract
Neuronal positioning is a fundamental process during brain development. Abnormalities in this process cause several types of brain malformations and are linked to neurodevelopmental disorders such as autism, intellectual disability, epilepsy, and schizophrenia. Little is known about the pathogenesis of developmental brain malformations associated with abnormal neuron positioning, which has hindered research into potential treatments. However, recent advances in neurogenetics provide clues to the pathogenesis of aberrant neuronal positioning by identifying causative genes. This may help us form a foundation upon which therapeutic tools can be developed. In this review, we first provide a brief overview of neural development and migration, as they relate to defects in neuronal positioning. We then discuss recent progress in identifying genes and brain malformations associated with aberrant neuronal positioning during human brain development.
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Affiliation(s)
- Jeffrey J Moffat
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, 985960 Nebraska Medical Center, Omaha, NE, 68198-5960, USA.
| | - Minhan Ka
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, 985960 Nebraska Medical Center, Omaha, NE, 68198-5960, USA.
| | - Eui-Man Jung
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, 985960 Nebraska Medical Center, Omaha, NE, 68198-5960, USA.
| | - Woo-Yang Kim
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, 985960 Nebraska Medical Center, Omaha, NE, 68198-5960, USA.
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13
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Hayashi K, Kubo KI, Kitazawa A, Nakajima K. Cellular dynamics of neuronal migration in the hippocampus. Front Neurosci 2015; 9:135. [PMID: 25964735 PMCID: PMC4408843 DOI: 10.3389/fnins.2015.00135] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 04/02/2015] [Indexed: 12/30/2022] Open
Abstract
A fine structure of the hippocampus is required for proper functions, and disruption of this formation by neuronal migration defects during development may play a role in some psychiatric illnesses. During hippocampal development in rodents, pyramidal neurons in the Ammon's horn are mostly generated in the ventricular zone (VZ), spent as multipolar cells just above the VZ, and then migrate radially toward the pial surface, ultimately settling into the hippocampal plate. Although this process is similar to that of neocortical projection neurons, these are not identical. In addition to numerous histological studies, the development of novel techniques gives a clear picture of the cellular dynamics of hippocampal neurons, as well as neocortical neurons. In this article, we provide an overview of the cellular mechanisms of rodent hippocampal neuronal migration including those of dentate granule cells, especially focusing on the differences of migration modes between hippocampal neurons and neocortical neurons. The unique migration mode of hippocampal pyramidal neurons might enable clonally related cells in the Ammon's horn to distribute in a horizontal fashion.
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Affiliation(s)
- Kanehiro Hayashi
- Department of Anatomy, Keio University School of Medicine Tokyo, Japan
| | - Ken-Ichiro Kubo
- Department of Anatomy, Keio University School of Medicine Tokyo, Japan
| | - Ayako Kitazawa
- Department of Anatomy, Keio University School of Medicine Tokyo, Japan
| | - Kazunori Nakajima
- Department of Anatomy, Keio University School of Medicine Tokyo, Japan
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Yap CC, Winckler B. Adapting for endocytosis: roles for endocytic sorting adaptors in directing neural development. Front Cell Neurosci 2015; 9:119. [PMID: 25904845 PMCID: PMC4389405 DOI: 10.3389/fncel.2015.00119] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Accepted: 03/16/2015] [Indexed: 01/01/2023] Open
Abstract
Proper cortical development depends on the orchestrated actions of a multitude of guidance receptors and adhesion molecules and their downstream signaling. The levels of these receptors on the surface and their precise locations can greatly affect guidance outcomes. Trafficking of receptors to a particular surface locale and removal by endocytosis thus feed crucially into the final guidance outcomes. In addition, endocytosis of receptors can affect downstream signaling (both quantitatively and qualitatively) and regulated endocytosis of guidance receptors is thus an important component of ensuring proper neural development. We will discuss the cell biology of regulated endocytosis and the impact on neural development. We focus our discussion on endocytic accessory proteins (EAPs) (such as numb and disabled) and how they regulate endocytosis and subsequent post-endocytic trafficking of their cognate receptors (such as Notch, TrkB, β-APP, VLDLR, and ApoER2).
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Affiliation(s)
- Chan Choo Yap
- Department of Neuroscience, University of Virginia Charlottesville, VA, USA
| | - Bettina Winckler
- Department of Neuroscience, University of Virginia Charlottesville, VA, USA
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15
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Murtaza M, Jolly LA, Gecz J, Wood SA. La FAM fatale: USP9X in development and disease. Cell Mol Life Sci 2015; 72:2075-89. [PMID: 25672900 PMCID: PMC4427618 DOI: 10.1007/s00018-015-1851-0] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 02/02/2015] [Accepted: 02/04/2015] [Indexed: 11/12/2022]
Abstract
Deubiquitylating enzymes (DUBs), act downstream of ubiquitylation. As such, these post-post-translational modifiers function as the final arbitrators of a protein substrate’s ubiquitylation status, thus regulating its fate. In most instances, DUBs moderate the absolute level of a substrate, its locality or activity, rather than being an “all-or-none” phenomenon. Yet, disruption of this quantitative regulation can produce dramatic qualitative differences. The ubiquitin-specific protease 9X (USP9X/FAM) is a substrate-specific DUB, which displays an extraordinarily high level of sequence conservation from Drosophila to mammals. It is primarily the recent revelations of USP9X’s pivotal role in human cancers, both as oncogene or tumour suppressor, in developmental disorders including intellectual disability, epilepsy, autism and developmental delay that has led to a subsequent re-examination of its molecular and cellular functions. Results from experimental animal models have implicated USP9X in neurodegeneration, including Parkinson’s and Alzheimer’s disease, as well as autoimmune diseases. In this review, we describe the current and accumulated knowledge on the molecular, cellular and developmental aspects of USP9X function within the context of the biological consequences during normal development and disease.
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Affiliation(s)
- Mariyam Murtaza
- The Eskitis Institute for Drug Discovery, Griffith University, Brisbane, QLD, Australia
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16
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Rakshambikai R, Manoharan M, Gnanavel M, Srinivasan N. Typical and atypical domain combinations in human protein kinases: functions, disease causing mutations and conservation in other primates. RSC Adv 2015. [DOI: 10.1039/c4ra11685b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A twist in the evolution of human kinases resulting in kinases with hybrid and rogue properties.
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Affiliation(s)
| | - Malini Manoharan
- Molecular Biophysics Unit
- Indian Institute of Science
- Bangalore 560012
- India
| | - Mutharasu Gnanavel
- Molecular Biophysics Unit
- Indian Institute of Science
- Bangalore 560012
- India
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17
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Moon HM, Wynshaw-Boris A. Cytoskeleton in action: lissencephaly, a neuronal migration disorder. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2014; 2:229-45. [PMID: 23495356 DOI: 10.1002/wdev.67] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
During neocortical development, the extensive migratory movements of neurons from their place of birth to their final location are essential for the coordinated wiring of synaptic circuits and proper neurological function. Failure or delay in neuronal migration causes severe abnormalities in cortical layering, which consequently results in human lissencephaly ('smooth brain'), a neuronal migration disorder. The brains of lissencephaly patients have less-convoluted gyri in the cerebral cortex with impaired cortical lamination of neurons. Since microtubule (MT) and actin-associated proteins play important functions in regulating the dynamics of MT and actin cytoskeletons during neuronal migration, genetic mutations or deletions of crucial genes involved in cytoskeletal processes lead to lissencephaly in human and neuronal migration defects in mouse. During neuronal migration, MT organization and transport are controlled by platelet-activating factor acetylhydrolase isoform 1b regulatory subunit 1 (PAFAH1B1, formerly known as LIS1, Lissencephaly-1), doublecortin (DCX), YWHAE, and tubulin. Actin stress fibers are modulated by PAFAH1B1 (LIS1), DCX, RELN, and VLDLR (very low-density lipoprotein receptor)/LRP8 (low-density lipoprotein-related receptor 8, formerly known as APOER2). There are several important levels of crosstalk between these two cytoskeletal systems to establish accurate cortical patterning in development. The recent understanding of the protein networks that govern neuronal migration by regulating cytoskeletal dynamics, from human and mouse genetics as well as molecular and cellular analyses, provides new insights on neuronal migration disorders and may help us devise novel therapeutic strategies for such brain malformations.
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18
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Homan CC, Kumar R, Nguyen LS, Haan E, Raymond FL, Abidi F, Raynaud M, Schwartz CE, Wood SA, Gecz J, Jolly LA. Mutations in USP9X are associated with X-linked intellectual disability and disrupt neuronal cell migration and growth. Am J Hum Genet 2014; 94:470-8. [PMID: 24607389 DOI: 10.1016/j.ajhg.2014.02.004] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 02/13/2014] [Indexed: 11/17/2022] Open
Abstract
With a wealth of disease-associated DNA variants being recently reported, the challenges of providing their functional characterization are mounting. Previously, as part of a large systematic resequencing of the X chromosome in 208 unrelated families with nonsyndromic X-linked intellectual disability, we identified three unique variants (two missense and one protein truncating) in USP9X. To assess the functional significance of these variants, we took advantage of the Usp9x knockout mouse we generated. Loss of Usp9x causes reduction in both axonal growth and neuronal cell migration. Although overexpression of wild-type human USP9X rescued these defects, all three USP9X variants failed to rescue axonal growth, caused reduced USP9X protein localization in axonal growth cones, and (in 2/3 variants) failed to rescue neuronal cell migration. Interestingly, in one of these families, the proband was subsequently identified to have a microdeletion encompassing ARID1B, a known ID gene. Given our findings it is plausible that loss of function of both genes contributes to the individual's phenotype. This case highlights the complexity of the interpretations of genetic findings from genome-wide investigations. We also performed proteomics analysis of neurons from both the wild-type and Usp9x knockout embryos and identified disruption of the cytoskeleton as the main underlying consequence of the loss of Usp9x. Detailed clinical assessment of all three families with USP9X variants identified hypotonia and behavioral and morphological defects as common features in addition to ID. Together our data support involvement of all three USP9X variants in ID in these families and provide likely cellular and molecular mechanisms involved.
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Affiliation(s)
- Claire C Homan
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA 5005, Australia
| | - Raman Kumar
- Women's and Children's Health Research Institute, North Adelaide, SA 5006, Australia; Discipline of Medicine, University of Adelaide, Adelaide, SA 5005, Australia; School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, SA 5005, Australia
| | - Lam Son Nguyen
- School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, SA 5005, Australia
| | - Eric Haan
- School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, SA 5005, Australia; South Australian Clinical Genetics Service, SA Pathology at Women's and Children's Hospital, North Adelaide, SA 5006, Australia
| | - F Lucy Raymond
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Fatima Abidi
- J.C. Self Research Institute, Greenwood Genetics Centre, Greenwood, SC 29646, USA
| | - Martine Raynaud
- CHRU de Tours, Service de Génétique, Tours 37000, France; Inserm U930, UMR Imagerie et Cerveau, Tours 37000, France
| | - Charles E Schwartz
- J.C. Self Research Institute, Greenwood Genetics Centre, Greenwood, SC 29646, USA
| | - Stephen A Wood
- Eskitis Institute for Drug Discovery, Griffith University, Brisbane, QLD 4111, Australia
| | - Jozef Gecz
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA 5005, Australia; Women's and Children's Health Research Institute, North Adelaide, SA 5006, Australia; School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, SA 5005, Australia; Robinson Institute, University of Adelaide, Adelaide, SA 5005, Australia.
| | - Lachlan A Jolly
- School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, SA 5005, Australia; Robinson Institute, University of Adelaide, Adelaide, SA 5005, Australia.
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Merz K, Lie DC. Evidence that Doublecortin is dispensable for the development of adult born neurons in mice. PLoS One 2013; 8:e62693. [PMID: 23667508 PMCID: PMC3647037 DOI: 10.1371/journal.pone.0062693] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 03/24/2013] [Indexed: 11/18/2022] Open
Abstract
In mammals, adult neural stem cells give rise to new hippocampal dentate granule neurons and interneurons of the olfactory bulb throughout life. The microtubule associated protein Doublecortin (DCX) is expressed by migrating neuroblasts and immature neurons, and is widely used as a stage-specific marker of adult neurogenesis and as a marker to identify neurogenic activity in the adult brain per se. Mutations in the DCX gene have been causally linked to human lissencephalic syndromes. Moreover, embryonic loss of DCX function interferes with neuronal migration and dendritic patterning in a species- and region-specific manner. A putative function of DCX in adult neurogenesis has not been directly explored. Here we show that overexpression of DCX in newly generated dentate granule neurons of the adult mouse brain has no effect on morphological maturation or migration. We also show that micro (mi) RNA-mediated retroviral knockdown of DCX does not alter morphological maturation of adult born dentate granule cells or migration of new neurons in either adult neurogenic niche. Thus, the present data indicate that DCX is dispensable for the development of new neurons in adult mice.
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Affiliation(s)
- Katharina Merz
- Research Group Adult Neurogenesis and Neural Stem Cells, Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich-Neuherberg, Germany
| | - D. Chichung Lie
- Research Group Adult Neurogenesis and Neural Stem Cells, Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich-Neuherberg, Germany
- Institute of Biochemistry, Emil Fischer Center, University of Erlangen-Nürnberg, Erlangen, Germany
- * E-mail:
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20
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DCLK1 variants are associated across schizophrenia and attention deficit/hyperactivity disorder. PLoS One 2012; 7:e35424. [PMID: 22539971 PMCID: PMC3335166 DOI: 10.1371/journal.pone.0035424] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Accepted: 03/15/2012] [Indexed: 11/19/2022] Open
Abstract
Doublecortin and calmodulin like kinase 1 (DCLK1) is implicated in synaptic plasticity and neurodevelopment. Genetic variants in DCLK1 are associated with cognitive traits, specifically verbal memory and general cognition. We investigated the role of DCLK1 variants in three psychiatric disorders that have neuro-cognitive dysfunctions: schizophrenia (SCZ), bipolar affective disorder (BP) and attention deficit/hyperactivity disorder (ADHD). We mined six genome wide association studies (GWASs) that were available publically or through collaboration; three for BP, two for SCZ and one for ADHD. We also genotyped the DCLK1 region in additional samples of cases with SCZ, BP or ADHD and controls that had not been whole-genome typed. In total, 9895 subjects were analysed, including 5308 normal controls and 4,587 patients (1,125 with SCZ, 2,496 with BP and 966 with ADHD). Several DCLK1 variants were associated with disease phenotypes in the different samples. The main effect was observed for rs7989807 in intron 3, which was strongly associated with SCZ alone and even more so when cases with SCZ and ADHD were combined (P-value = 4×10−5 and 4×10−6, respectively). Associations were also observed with additional markers in intron 3 (combination of SCZ, ADHD and BP), intron 19 (SCZ+BP) and the 3′UTR (SCZ+BP). Our results suggest that genetic variants in DCLK1 are associated with SCZ and, to a lesser extent, with ADHD and BP. Interestingly the association is strongest when SCZ and ADHD are considered together, suggesting common genetic susceptibility. Given that DCLK1 variants were previously found to be associated with cognitive traits, these results are consistent with the role of DCLK1 in neurodevelopment and synaptic plasticity.
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21
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Schneider C, Krischke G, Rascher W, Gassmann M, Trollmann R. Systemic hypoxia differentially affects neurogenesis during early mouse brain maturation. Brain Dev 2012; 34:261-73. [PMID: 21824737 DOI: 10.1016/j.braindev.2011.07.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 07/07/2011] [Accepted: 07/08/2011] [Indexed: 11/30/2022]
Abstract
BACKGROUND Cerebral tissue oxygen level modifies crucial processes of neurogenesis, glial and neuronal development during physiological and hypoxic conditions. Whether hypoxia-sensitive factors such as doublecortin (DCX) and hypoxia-inducible transcription factor (HIF)-regulated CXCR4 and SDF-1 modify and activate adaptation to hypoxia in developing brain is not well understood. Present study investigated maturational regulation of oxygen-sensitive developmental genes and proteins in developing mouse brain in relation to the degree of hypoxia. METHODS Physiological expression of HIF-1, CXCR4, SDF-1 and DCX were analyzed in the brain of C57/BL6 mice (P0-P60). In addition, mice (P0, P7) were exposed to normoxia, acute (8% O(2), 6 h) or chronic hypoxia (10% O(2), 7 d) followed by reoxygenation. Gene expression was analyzed by quantitative PCR, proteins were quantified by Western blot analysis and immunohistochemistry. RESULTS Cerebral HIF-1α protein, CXCR4 and DCX mRNA levels showed maturational stage-related peak levels at P0/P1, whereas SDF-1 mRNA levels were highest at P17. CXCR4 and SDF-1 mRNA levels were not altered in response to hypoxia. Whereas DCX mRNA levels significantly increased during acute hypoxia, down-regulation of DCX transcripts was found in response to chronic hypoxia compared to controls, and these changes were related to specifically vulnerable brain regions. CONCLUSIONS Maturational stage-related dynamic changes of HIF-1α, CXCR4, SDF-1 and DCX may reflect involvement of hypoxia-regulated systems in important developmental regulatory processes of the developing brain. Extending the knowledge of differential effects of hypoxia on neurogenesis and dynamic regulatory networks present data provide a basis for future research on gestational age-specific neuroprotective options.
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Affiliation(s)
- Christina Schneider
- Department of Pediatrics, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
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22
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Manent JB, Beguin S, Ganay T, Represa A. Cell-autonomous and cell-to-cell signalling events in normal and altered neuronal migration. Eur J Neurosci 2012; 34:1595-608. [PMID: 22103417 DOI: 10.1111/j.1460-9568.2011.07867.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cerebral cortex is a complex six-layered structure that contains an important diversity of neurons, and has rich local and extrinsic connectivity. Among the mechanisms governing the cerebral cortex construction, neuronal migration is perhaps the most crucial as it ensures the timely formation of specific and selective neuronal circuits. Here, we review the main extrinsic and extrinsic factors involved in regulating neuronal migration in the cortex and describe some environmental factors interfering with their actions.
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23
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Schenk GJ, Vreugdenhil E, Hubens CJY, Veldhuisen B, de Kloet ER, Oitzl MS. Hippocampal CARP over-expression solidifies consolidation of contextual fear memories. Physiol Behav 2010; 102:323-31. [PMID: 21130104 DOI: 10.1016/j.physbeh.2010.11.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 11/15/2010] [Accepted: 11/18/2010] [Indexed: 01/13/2023]
Abstract
The Doublecortin-Like Kinase (DCLK) gene is involved in neuronal migration during development. Through alternative splicing the DCLK gene also produces a transcript called Ca(2+)/calmodulin dependent protein kinase (CaMK)-related peptide (CARP) that is expressed exclusively during adulthood in response to neuronal activity. The function of CARP, however, is poorly understood. To study CARP function, we have generated transgenic mice with over-expression of the CARP transcript in, amongst other brain areas, the hippocampus. We aimed to characterize possible behavioral adaptations of these mice by using a Pavlovian fear conditioning approach. This type of fear conditioning, in which both the hippocampus and amygdala are critically involved, allows studying the formation and extinction of fear related memories. We here report on the behavioral adaptations of two distinct transgenic lines: one with high levels of CARP in the hippocampus and amygdala, whilst the other has high levels of CARP in the hippocampal formation, but not in the amygdala. We tested both mouse lines separately by comparing them to their wild-type littermate controls. We provide evidence suggesting consolidation of contextual fear memories is strengthened in mice of both transgenic lines.
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Affiliation(s)
- Geert J Schenk
- Division of Medical Pharmacology, Leiden/Amsterdam Centre for Drug Research, Einsteinweg 55, 2333 CC Leiden, The Netherlands.
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Abstract
Neuronal migration is, along with axon guidance, one of the fundamental mechanisms underlying the wiring of the brain. As other organs, the nervous system has acquired the ability to grow both in size and complexity by using migration as a strategy to position cell types from different origins into specific coordinates, allowing for the generation of brain circuitries. Guidance of migrating neurons shares many features with axon guidance, from the use of substrates to the specific cues regulating chemotaxis. There are, however, important differences in the cell biology of these two processes. The most evident case is nucleokinesis, which is an essential component of migration that needs to be integrated within the guidance of the cell. Perhaps more surprisingly, the cellular mechanisms underlying the response of the leading process of migrating cells to guidance cues might be different to those involved in growth cone steering, at least for some neuronal populations.
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Affiliation(s)
- Oscar Marín
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas and Universidad Miguel Hernández, Sant Joan d'Alacant 03550, Spain.
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25
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Schenk GJ, Werkman T, Wadman W, Veldhuisen B, Dijkmans TF, Blaas E, Kegel L, de Kloet ER, Vreugdenhil E. Over-expression of the DCLK gene transcript CARP decreases CA3/CA1 network excitability. Brain Res 2010; 1352:21-34. [DOI: 10.1016/j.brainres.2010.07.068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 07/19/2010] [Accepted: 07/19/2010] [Indexed: 12/18/2022]
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26
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Schenk GJ, Veldhuisen B, Wedemeier O, McGown CC, Schouten TG, Oitzl M, de Kloet ER, Vreugdenhil E. Over-expression of δC-DCLK-short in mouse brain results in a more anxious behavioral phenotype. Physiol Behav 2010; 101:541-8. [PMID: 20705078 DOI: 10.1016/j.physbeh.2010.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 07/26/2010] [Accepted: 08/04/2010] [Indexed: 10/19/2022]
Abstract
Products of the Doublecortin-Like Kinase (DCLK) gene are associated with cortical migration and hippocampal maturation during embryogenesis. However, the functions of those DCLK gene transcripts that encode kinases and are expressed during adulthood are incompletely understood. To elucidate potential functions of these DCLK gene splice variants we have generated and analyzed transgenic mice with neuronal over-expression of a truncated, constitutively active form of DCLK-short, designated δC-DCLK-short. Previously, we have performed an extensive molecular characterization of these transgenic δC-DCLK-short mice and established that a specific subunit of the GABA(A) receptor, which is involved in anxiety-related GABAergic neurotransmission, is down-regulated in the hippocampus. Here we show that δC-DCLK-short mRNA is highly expressed in the hippocampus, cortex and amygdala of transgenic mice. We provide evidence that the δC-DCLK-short protein is expressed and functional. In addition, we examined anxiety-related behavior in δC-DCLK-short mice in the elevated plus maze. Interestingly, δC-DCLK-short mice spend less time, move less in the open arms of the maze and show a reduction in the number of rim dips. These behaviors indicate that δC-DCLK-short mice display a more anxious behavioral phenotype.
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Affiliation(s)
- Geert J Schenk
- Division of Medical Pharmacology, Leiden/Amsterdam Centre for Drug Research, Einsteinweg 55, 2300 RA Leiden, The Netherlands.
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27
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Wynshaw-Boris A, Pramparo T, Youn YH, Hirotsune S. Lissencephaly: mechanistic insights from animal models and potential therapeutic strategies. Semin Cell Dev Biol 2010; 21:823-30. [PMID: 20688183 DOI: 10.1016/j.semcdb.2010.07.008] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Accepted: 07/25/2010] [Indexed: 12/11/2022]
Abstract
Lissencephaly is a severe human neuronal migration defect characterized by a smooth cerebral surface, mental retardation and seizures. The two most common genes mutated in patients with lissencephaly are LIS1 and DCX. LIS1 was the first gene cloned that was important for neuronal migration in any organism, and heterozygous mutations or deletions of LIS1 are found in the majority of patients with lissencephaly, while DCX mutations were found in males with X-linked lissencephaly. In this review, we will discuss how an understanding of the molecular and cellular pathways disrupted in model organisms with Lis1 and Dcx mutations or knock-down not only provide insights into the normal processes of neuronal migration, including neurogenesis, but they also may lead to potential novel therapeutic strategies for these severe cortical malformations.
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28
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Le Hellard S, Håvik B, Espeseth T, Breilid H, Løvlie R, Luciano M, Gow AJ, Harris SE, Starr JM, Wibrand K, Lundervold AJ, Porteous DJ, Bramham CR, Deary IJ, Reinvang I, Steen VM. Variants in doublecortin- and calmodulin kinase like 1, a gene up-regulated by BDNF, are associated with memory and general cognitive abilities. PLoS One 2009; 4:e7534. [PMID: 19844571 PMCID: PMC2760101 DOI: 10.1371/journal.pone.0007534] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 09/24/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Human memory and general cognitive abilities are complex functions of high heritability and wide variability in the population. The brain-derived neurotrophic factor (BDNF) plays an important role in mammalian memory formation. METHODOLOGY / PRINCIPAL FINDING Based on the identification of genes markedly up-regulated during BDNF-induced synaptic consolidation in the hippocampus, we selected genetic variants that were tested in three independent samples, from Norway and Scotland, of adult individuals examined for cognitive abilities. In all samples, we show that markers in the doublecortin- and calmodulin kinase like 1 (DCLK1) gene, are significantly associated with general cognition (IQ scores) and verbal memory function, resisting multiple testing. DCLK1 is a complex gene with multiple transcripts which vary in expression and function. We show that the short variants are all up-regulated after BDNF treatment in the rat hippocampus, and that they are expressed in the adult human brain (mostly in cortices and hippocampus). We demonstrate that several of the associated variants are located in potential alternative promoter- and cis-regulatory elements of the gene and that they affect BDNF-mediated expression of short DCLK1 transcripts in a reporter system. CONCLUSION These data present DCLK1 as a functionally pertinent gene involved in human memory and cognitive functions.
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Affiliation(s)
- Stéphanie Le Hellard
- Bergen Mental Health Research Center, Department of Clinical Medicine, University of Bergen, Bergen, Norway.
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Jessberger S, Gage FH, Eisch AJ, Lagace DC. Making a neuron: Cdk5 in embryonic and adult neurogenesis. Trends Neurosci 2009; 32:575-82. [PMID: 19782409 DOI: 10.1016/j.tins.2009.07.002] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 07/06/2009] [Accepted: 07/07/2009] [Indexed: 01/02/2023]
Abstract
Cyclin-dependent kinase 5 (Cdk5) has been implicated in the migration, maturation and survival of neurons born during embryonic development. New evidence suggests that Cdk5 has comparable but also distinct functions in adult neurogenesis. Here we summarize accumulating evidence on the role of Cdk5 in regulation of the cell cycle, migration, survival, maturation and neuronal integration. We specifically highlight the many similarities and few tantalizing differences in the roles of Cdk5 in the embryonic and adult brain. We discuss the signaling pathways that might contribute to Cdk5 action in regulating embryonic and adult neurogenesis, highlighting future research directions that will help to clarify the mechanisms underlying lifelong neurogenesis in the mammalian brain.
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Affiliation(s)
- Sebastian Jessberger
- Institute of Cell Biology, Department of Biology, ETH Zurich, Schafmattstrasse 18, 8093 Zurich, Switzerland.
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30
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Mérot Y, Rétaux S, Heng JIT. Molecular mechanisms of projection neuron production and maturation in the developing cerebral cortex. Semin Cell Dev Biol 2009; 20:726-34. [PMID: 19442543 DOI: 10.1016/j.semcdb.2009.04.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 03/18/2009] [Accepted: 04/01/2009] [Indexed: 12/20/2022]
Abstract
The cerebral cortex is a brain structure unique to mammals and highly adapted to process complex information. Through multiple developmental steps, the cerebral cortex is assembled as a huge diversity of neurons comprising a complex laminar structure, and with both local and long-distance connectivity within the nervous system. Key processes must take place during its construction, including: (i) regulation of the correct number of neurons produced by progenitor cells, (ii) temporal and spatial generation of neuronal diversity, and (iii) control of neuron migration and laminar positioning as well as terminal differentiation within the mature cortex. Here, we seek to highlight recent cellular and molecular findings underlying these sequential steps of neurogenesis, cell fate specification and migration during cortical development, with particular emphasis on cortical projection neurons.
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Affiliation(s)
- Yohann Mérot
- DECA Group, DEPSN UPR2197 CNRS, Avenue de la terrasse 91198 Gif sur Yvette, France.
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Boekhoorn K, Sarabdjitsingh A, Kommerie H, de Punder K, Schouten T, Lucassen PJ, Vreugdenhil E. Doublecortin (DCX) and doublecortin-like (DCL) are differentially expressed in the early but not late stages of murine neocortical development. J Comp Neurol 2008; 507:1639-52. [PMID: 18231966 DOI: 10.1002/cne.21646] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
During corticogenesis, radial glia-derived neural progenitors divide and migrate along radial fibers to their designated positions within the cortical plate. The microtubule-associated proteins doublecortin (DCX) and doublecortin-like (DCL) are critically involved in neuronal migration and division, and may function in a partially redundant pathway. Since little is known about the important early stages of corticogenesis, when neurogenesis is extensive, we addressed a possible differential role by examining spatiotemporal expression patterns of DCX, DCL, and the radial glia marker vimentin during murine development. We found expression patterns of DCL and DCX to differ remarkably prior to embryonic day (E)13. DCL was already expressed at E9 and largely overlapped with vimentin, whereas DCX expression started modestly from E10/E11 onward. DCL was mainly found in the ventricular zone, often in mitotic cells and in pial-oriented radial fibers. In contrast, DCX was expressed in tangential fibers in the outer cortical regions. After E13, DCX and DCL expression largely overlapped but DCL expression had disappeared from the ventricular zone. Also, DCL levels were attenuated, whereas DCX remained high beyond E17. In conclusion, DCX and DCL are differentially expressed, particularly during early corticogenesis, consistent with their different functional roles. Given its involvement in mitosis, DCL appears to have a unique role in the early neuroepithelium that is different from later developmental stages when DCX is coexpressed.
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Affiliation(s)
- Karin Boekhoorn
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, The Netherlands
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Pedotti P, 't Hoen PAC, Vreugdenhil E, Schenk GJ, Vossen RH, Ariyurek Y, de Hollander M, Kuiper R, van Ommen GJB, den Dunnen JT, Boer JM, de Menezes RX. Can subtle changes in gene expression be consistently detected with different microarray platforms? BMC Genomics 2008; 9:124. [PMID: 18331641 PMCID: PMC2335120 DOI: 10.1186/1471-2164-9-124] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Accepted: 03/10/2008] [Indexed: 11/29/2022] Open
Abstract
Background The comparability of gene expression data generated with different microarray platforms is still a matter of concern. Here we address the performance and the overlap in the detection of differentially expressed genes for five different microarray platforms in a challenging biological context where differences in gene expression are few and subtle. Results Gene expression profiles in the hippocampus of five wild-type and five transgenic δC-doublecortin-like kinase mice were evaluated with five microarray platforms: Applied Biosystems, Affymetrix, Agilent, Illumina, LGTC home-spotted arrays. Using a fixed false discovery rate of 10% we detected surprising differences between the number of differentially expressed genes per platform. Four genes were selected by ABI, 130 by Affymetrix, 3,051 by Agilent, 54 by Illumina, and 13 by LGTC. Two genes were found significantly differentially expressed by all platforms and the four genes identified by the ABI platform were found by at least three other platforms. Quantitative RT-PCR analysis confirmed 20 out of 28 of the genes detected by two or more platforms and 8 out of 15 of the genes detected by Agilent only. We observed improved correlations between platforms when ranking the genes based on the significance level than with a fixed statistical cut-off. We demonstrate significant overlap in the affected gene sets identified by the different platforms, although biological processes were represented by only partially overlapping sets of genes. Aberrances in GABA-ergic signalling in the transgenic mice were consistently found by all platforms. Conclusion The different microarray platforms give partially complementary views on biological processes affected. Our data indicate that when analyzing samples with only subtle differences in gene expression the use of two different platforms might be more attractive than increasing the number of replicates. Commercial two-color platforms seem to have higher power for finding differentially expressed genes between groups with small differences in expression.
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Affiliation(s)
- Paola Pedotti
- Center for Human and Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands.
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