1
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Tanaka T, Chung HL. Exploiting fly models to investigate rare human neurological disorders. Neural Regen Res 2025; 20:21-28. [PMID: 38767473 PMCID: PMC11246155 DOI: 10.4103/nrr.nrr-d-23-01847] [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: 11/09/2023] [Revised: 02/05/2024] [Accepted: 03/02/2024] [Indexed: 05/22/2024] Open
Abstract
Rare neurological diseases, while individually are rare, collectively impact millions globally, leading to diverse and often severe neurological symptoms. Often attributed to genetic mutations that disrupt protein function or structure, understanding their genetic basis is crucial for accurate diagnosis and targeted therapies. To investigate the underlying pathogenesis of these conditions, researchers often use non-mammalian model organisms, such as Drosophila (fruit flies), which is valued for their genetic manipulability, cost-efficiency, and preservation of genes and biological functions across evolutionary time. Genetic tools available in Drosophila, including CRISPR-Cas9, offer a means to manipulate gene expression, allowing for a deep exploration of the genetic underpinnings of rare neurological diseases. Drosophila boasts a versatile genetic toolkit, rapid generation turnover, and ease of large-scale experimentation, making it an invaluable resource for identifying potential drug candidates. Researchers can expose flies carrying disease-associated mutations to various compounds, rapidly pinpointing promising therapeutic agents for further investigation in mammalian models and, ultimately, clinical trials. In this comprehensive review, we explore rare neurological diseases where fly research has significantly contributed to our understanding of their genetic basis, pathophysiology, and potential therapeutic implications. We discuss rare diseases associated with both neuron-expressed and glial-expressed genes. Specific cases include mutations in CDK19 resulting in epilepsy and developmental delay, mutations in TIAM1 leading to a neurodevelopmental disorder with seizures and language delay, and mutations in IRF2BPL causing seizures, a neurodevelopmental disorder with regression, loss of speech, and abnormal movements. And we explore mutations in EMC1 related to cerebellar atrophy, visual impairment, psychomotor retardation, and gain-of-function mutations in ACOX1 causing Mitchell syndrome. Loss-of-function mutations in ACOX1 result in ACOX1 deficiency, characterized by very-long-chain fatty acid accumulation and glial degeneration. Notably, this review highlights how modeling these diseases in Drosophila has provided valuable insights into their pathophysiology, offering a platform for the rapid identification of potential therapeutic interventions. Rare neurological diseases involve a wide range of expression systems, and sometimes common phenotypes can be found among different genes that cause abnormalities in neurons or glia. Furthermore, mutations within the same gene may result in varying functional outcomes, such as complete loss of function, partial loss of function, or gain-of-function mutations. The phenotypes observed in patients can differ significantly, underscoring the complexity of these conditions. In conclusion, Drosophila represents an indispensable and cost-effective tool for investigating rare neurological diseases. By facilitating the modeling of these conditions, Drosophila contributes to a deeper understanding of their genetic basis, pathophysiology, and potential therapies. This approach accelerates the discovery of promising drug candidates, ultimately benefiting patients affected by these complex and understudied diseases.
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Affiliation(s)
- Tomomi Tanaka
- Department of Neurology, Houston Methodist Research Institute, Houston, TX, USA
| | - Hyung-Lok Chung
- Department of Neurology, Houston Methodist Research Institute, Houston, TX, USA
- Department of Neurology, Weill Cornell Medical College, New York, NY, USA
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2
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Rao S, Liang F, Herring BE. RhoGEF Tiam2 Regulates Glutamatergic Synaptic Transmission in Hippocampal CA1 Pyramidal Neurons. eNeuro 2024; 11:ENEURO.0500-21.2024. [PMID: 38871458 PMCID: PMC11262554 DOI: 10.1523/eneuro.0500-21.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 03/29/2024] [Accepted: 05/23/2024] [Indexed: 06/15/2024] Open
Abstract
Glutamatergic synapses exhibit significant molecular diversity, but circuit-specific mechanisms that underlie synaptic regulation are not well characterized. Prior reports show that Rho-guanine nucleotide exchange factor (RhoGEF) Tiam1 regulates perforant path→dentate gyrus granule neuron synapses. In the present study, we report Tiam1's homolog Tiam2 is implicated in glutamatergic neurotransmission in CA1 pyramidal neurons. We find that Tiam2 regulates evoked excitatory glutamatergic currents via a postsynaptic mechanism mediated by the catalytic Dbl-homology domain. Overall, we present evidence for RhoGEF Tiam2's role in glutamatergic synapse function at Schaffer collateral→CA1 pyramidal neuron synapses.
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Affiliation(s)
- Sadhna Rao
- Department of Biological Sciences, Neurobiology Section, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California 90089
| | - Feng Liang
- Department of Biological Sciences, Neurobiology Section, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California 90089
| | - Bruce E Herring
- Department of Biological Sciences, Neurobiology Section, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California 90089
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3
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Svec KV, Howe AK. Protein Kinase A in cellular migration—Niche signaling of a ubiquitous kinase. Front Mol Biosci 2022; 9:953093. [PMID: 35959460 PMCID: PMC9361040 DOI: 10.3389/fmolb.2022.953093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 06/30/2022] [Indexed: 12/28/2022] Open
Abstract
Cell migration requires establishment and maintenance of directional polarity, which in turn requires spatial heterogeneity in the regulation of protrusion, retraction, and adhesion. Thus, the signaling proteins that regulate these various structural processes must also be distinctly regulated in subcellular space. Protein Kinase A (PKA) is a ubiquitous serine/threonine kinase involved in innumerable cellular processes. In the context of cell migration, it has a paradoxical role in that global inhibition or activation of PKA inhibits migration. It follows, then, that the subcellular regulation of PKA is key to bringing its proper permissive and restrictive functions to the correct parts of the cell. Proper subcellular regulation of PKA controls not only when and where it is active but also specifies the targets for that activity, allowing the cell to use a single, promiscuous kinase to exert distinct functions within different subcellular niches to facilitate cell movement. In this way, understanding PKA signaling in migration is a study in context and in the elegant coordination of distinct functions of a single protein in a complex cellular process.
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Affiliation(s)
- Kathryn V. Svec
- Department of Pharmacology, University of Vermont, Burlington, VT, United States
| | - Alan K. Howe
- Department of Pharmacology, University of Vermont, Burlington, VT, United States
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, V T, United States
- University of Vermont Cancer Center, University of Vermont, Burlington, VT, United States
- *Correspondence: Alan K. Howe,
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4
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Lu S, Hernan R, Marcogliese PC, Huang Y, Gertler TS, Akcaboy M, Liu S, Chung HL, Pan X, Sun X, Oguz MM, Oztoprak U, de Baaij JH, Ivanisevic J, McGinnis E, Guillen Sacoto MJ, Chung WK, Bellen HJ. Loss-of-function variants in TIAM1 are associated with developmental delay, intellectual disability, and seizures. Am J Hum Genet 2022; 109:571-586. [PMID: 35240055 DOI: 10.1016/j.ajhg.2022.01.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 01/27/2022] [Indexed: 12/13/2022] Open
Abstract
TIAM Rac1-associated GEF 1 (TIAM1) regulates RAC1 signaling pathways that affect the control of neuronal morphogenesis and neurite outgrowth by modulating the actin cytoskeletal network. To date, TIAM1 has not been associated with a Mendelian disorder. Here, we describe five individuals with bi-allelic TIAM1 missense variants who have developmental delay, intellectual disability, speech delay, and seizures. Bioinformatic analyses demonstrate that these variants are rare and likely pathogenic. We found that the Drosophila ortholog of TIAM1, still life (sif), is expressed in larval and adult central nervous system (CNS) and is mainly expressed in a subset of neurons, but not in glia. Loss of sif reduces the survival rate, and the surviving adults exhibit climbing defects, are prone to severe seizures, and have a short lifespan. The TIAM1 reference (Ref) cDNA partially rescues the sif loss-of-function (LoF) phenotypes. We also assessed the function associated with three TIAM1 variants carried by two of the probands and compared them to the TIAM1 Ref cDNA function in vivo. TIAM1 p.Arg23Cys has reduced rescue ability when compared to TIAM1 Ref, suggesting that it is a partial LoF variant. In ectopic expression studies, both wild-type sif and TIAM1 Ref are toxic, whereas the three variants (p.Leu862Phe, p.Arg23Cys, and p.Gly328Val) show reduced toxicity, suggesting that they are partial LoF variants. In summary, we provide evidence that sif is important for appropriate neural function and that TIAM1 variants observed in the probands are disruptive, thus implicating loss of TIAM1 in neurological phenotypes in humans.
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5
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Abstract
Cell migration, a crucial step in numerous biological processes, is tightly regulated in space and time. Cells employ Rho GTPases, primarily Rho, Rac, and Cdc42, to regulate their motility. Like other small G proteins, Rho GTPases function as biomolecular switches in regulating cell migration by operating between GDP bound 'OFF' and GTP bound 'ON' states. Guanine nucleotide exchange factors (GEFs) catalyse the shuttling of GTPases from OFF to ON state. G protein-coupled receptors (GPCRs) are the largest family of cell surface receptors that are involved in many signalling phenomena including cell survival and cell migration events. In this review, we summarize signalling mechanisms, involving GPCRs, leading to the activation of RhoGEFs. GPCRs exhibit diverse GEF activation modes that include the interaction of heterotrimeric G protein subunits with different domains of GEFs, phosphorylation, protein-protein interaction, protein-lipid interaction, and/or a combination of these processes.
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Affiliation(s)
- Aishwarya Omble
- Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, India,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Kiran Kulkarni
- Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, India,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India,CONTACT Kiran Kulkarni Academy of Scientific and Innovative Research (Acsir), Ghaziabad 201002, India
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6
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Maltas J, Reed H, Porter A, Malliri A. Mechanisms and consequences of dysregulation of the Tiam family of Rac activators in disease. Biochem Soc Trans 2020; 48:2703-2719. [PMID: 33200195 DOI: 10.1042/bst20200481] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/16/2020] [Accepted: 10/16/2020] [Indexed: 12/14/2022]
Abstract
The Tiam family proteins - Tiam1 and Tiam2/STEF - are Rac1-specific Guanine Nucleotide Exchange Factors (GEFs) with important functions in epithelial, neuronal, immune and other cell types. Tiam GEFs regulate cellular migration, proliferation and survival, mainly through activating and directing Rac1 signalling. Dysregulation of the Tiam GEFs is significantly associated with human diseases including cancer, immunological and neurological disorders. Uncovering the mechanisms and consequences of dysregulation is therefore imperative to improving the diagnosis and treatment of diseases. Here we compare and contrast the subcellular localisation and function of Tiam1 and Tiam2/STEF, and review the evidence for their dysregulation in disease.
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Affiliation(s)
- Joe Maltas
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park SK10 4TG, U.K
| | - Hannah Reed
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park SK10 4TG, U.K
| | - Andrew Porter
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park SK10 4TG, U.K
| | - Angeliki Malliri
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park SK10 4TG, U.K
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7
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Lavanderos B, Silva I, Cruz P, Orellana-Serradell O, Saldías MP, Cerda O. TRP Channels Regulation of Rho GTPases in Brain Context and Diseases. Front Cell Dev Biol 2020; 8:582975. [PMID: 33240883 PMCID: PMC7683514 DOI: 10.3389/fcell.2020.582975] [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: 07/13/2020] [Accepted: 10/05/2020] [Indexed: 12/13/2022] Open
Abstract
Neurological and neuropsychiatric disorders are mediated by several pathophysiological mechanisms, including developmental and degenerative abnormalities caused primarily by disturbances in cell migration, structural plasticity of the synapse, and blood-vessel barrier function. In this context, critical pathways involved in the pathogenesis of these diseases are related to structural, scaffolding, and enzymatic activity-bearing proteins, which participate in Ca2+- and Ras Homologs (Rho) GTPases-mediated signaling. Rho GTPases are GDP/GTP binding proteins that regulate the cytoskeletal structure, cellular protrusion, and migration. These proteins cycle between GTP-bound (active) and GDP-bound (inactive) states due to their intrinsic GTPase activity and their dynamic regulation by GEFs, GAPs, and GDIs. One of the most important upstream inputs that modulate Rho GTPases activity is Ca2+ signaling, positioning ion channels as pivotal molecular entities for Rho GTPases regulation. Multiple non-selective cationic channels belonging to the Transient Receptor Potential (TRP) family participate in cytoskeletal-dependent processes through Ca2+-mediated modulation of Rho GTPases. Moreover, these ion channels have a role in several neuropathological events such as neuronal cell death, brain tumor progression and strokes. Although Rho GTPases-dependent pathways have been extensively studied, how they converge with TRP channels in the development or progression of neuropathologies is poorly understood. Herein, we review recent evidence and insights that link TRP channels activity to downstream Rho GTPase signaling or modulation. Moreover, using the TRIP database, we establish associations between possible mediators of Rho GTPase signaling with TRP ion channels. As such, we propose mechanisms that might explain the TRP-dependent modulation of Rho GTPases as possible pathways participating in the emergence or maintenance of neuropathological conditions.
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Affiliation(s)
- Boris Lavanderos
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile
| | - Ian Silva
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile
| | - Pablo Cruz
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile
| | - Octavio Orellana-Serradell
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile
| | - María Paz Saldías
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile
| | - Oscar Cerda
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile.,The Wound Repair, Treatment and Health (WoRTH) Initiative, Santiago, Chile
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8
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Chu CH, Chen JS, Chuang PC, Su CH, Chan YL, Yang YJ, Chiang YT, Su YY, Gean PW, Sun HS. TIAM2S as a novel regulator for serotonin level enhances brain plasticity and locomotion behavior. FASEB J 2020; 34:3267-3288. [PMID: 31908036 DOI: 10.1096/fj.201901323r] [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: 05/25/2019] [Revised: 10/18/2019] [Accepted: 12/23/2019] [Indexed: 11/11/2022]
Abstract
TIAM2S, the short form of human T-cell lymphoma invasion and metastasis 2, can have oncogenic effects when aberrantly expressed in the liver or lungs. However, it is also abundant in healthy, non-neoplastic brain tissue, in which its primary function is still unknown. Here, we examined the neurobiological and behavioral significance of human TIAM2S using the human brain protein panels, a human NT2/D1-derived neuronal cell line model (NT2/N), and transgenic mice that overexpress human TIAM2S (TIAM2S-TG). Our data reveal that TIAM2S exists primarily in neurons of the restricted brain areas around the limbic system and in well-differentiated NT2/N cells. Functional studies revealed that TIAM2S has no guanine nucleotide exchange factor (GEF) activity and is mainly located in the nucleus. Furthermore, whole-transcriptome and enrichment analysis with total RNA sequencing revealed that TIAM2S-knockdown (TIAM2S-KD) was strongly associated with the cellular processes of the brain structural development and differentiation, serotonin-related signaling, and the diseases markers representing neurobehavioral developmental disorders. Moreover, TIAM2S-KD cells display decreased neurite outgrowth and reduced serotonin levels. Moreover, TIAM2S overexpressing TG mice show increased number and length of serotonergic fibers at early postnatal stage, results in higher serotonin levels at both the serum and brain regions, and higher neuroplasticity and hyperlocomotion in latter adulthood. Taken together, our results illustrate the non-oncogenic functions of human TIAM2S and demonstrate that TIAM2S is a novel regulator of serotonin level, brain neuroplasticity, and locomotion behavior.
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Affiliation(s)
- Chun-Hsien Chu
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jia-Shing Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Pei-Chin Chuang
- Department of Medical Research, Chang Gung Memorial Hospital, Kaohsiung, Taiwan.,Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chia-Hao Su
- Institute for Translational Research in Biomedicine, Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Ya-Ling Chan
- Department of Biotechnology and Bioindustry Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Ying-Ju Yang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Ting Chiang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Ya Su
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Po-Wu Gean
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Department of Biotechnology and Bioindustry Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan.,Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - H Sunny Sun
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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9
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Muraishi A, Haneta E, Saito Y, Hitomi Y, Sano M, Noguchi N. Hydrogen Peroxide-Reducing Factor Released by PC12D Cells Increases Cell Tolerance against Oxidative Stress. Biol Pharm Bull 2018; 41:777-785. [PMID: 29709915 DOI: 10.1248/bpb.b18-00016] [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: 02/05/2023]
Abstract
PC12D cells, a subline of rat adrenal pheochromocytoma PC12 cells, extend neurites rapidly in response to differentiation stimuli and are used to investigate the molecular mechanisms of neurite extension. In the present study, we found significant tolerance of PC12D cells against Parkinson's disease-related stimuli such as dopamine and 6-hydroxydopamine; this tolerance was significantly decreased by a change in the medium. Conditioned medium from PC12D cells induced tolerance against oxidative stress, which suggests that cytoprotective factor may be released by PC12D cells into the culture medium. Conditioned medium-induced tolerance was not found for PC12 cells or human neuroblastoma SH-SY5Y cells. A cytoprotective factor generated by PC12D cells exhibited hydrogen peroxide-reducing activity. Chemical characterization showed that this cytoprotective factor is water soluble and has a molecular weight about 1000 Da, and that its activity is inhibited by sodium cyanide. Release of this cytoprotective factor was increased by differentiation stimuli and oxidative stress. Taken together, these results suggest that release of a hydrogen peroxide-reducing factor by PC12D cells increases cell tolerance against oxidative stress. This study provides new insights into the antioxidative properties of factors in extracellular fluid.
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Affiliation(s)
- Asami Muraishi
- Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University
| | - Emi Haneta
- Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University
| | - Yoshiro Saito
- Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University
| | - Yutaka Hitomi
- Department of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University
| | - Mamoru Sano
- Department of Biology, Kyoto Prefectural University of Medicine
| | - Noriko Noguchi
- Systems Life Sciences Laboratory, Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University
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10
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Sessa A, Ciabatti E, Drechsel D, Massimino L, Colasante G, Giannelli S, Satoh T, Akira S, Guillemot F, Broccoli V. The Tbr2 Molecular Network Controls Cortical Neuronal Differentiation Through Complementary Genetic and Epigenetic Pathways. Cereb Cortex 2018; 27:3378-3396. [PMID: 27600842 DOI: 10.1093/cercor/bhw270] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 08/04/2016] [Indexed: 01/21/2023] Open
Abstract
The T-box containing Tbr2 gene encodes for a transcription factor essential for the specification of the intermediate neural progenitors (INPs) originating the excitatory neurons of the cerebral cortex. However, its overall mechanism of action, direct target genes and cofactors remain unknown. Herein, we carried out global gene expression profiling combined with genome-wide binding site identification to determine the molecular pathways regulated by TBR2 in INPs. This analysis led to the identification of novel protein-protein interactions that control multiple features of INPs including cell-type identity, morphology, proliferation and migration dynamics. In particular, NEUROG2 and JMJD3 were found to associate with TBR2 revealing unexplored TBR2-dependent mechanisms. These interactions can explain, at least in part, the role of this transcription factor in the implementation of the molecular program controlling developmental milestones during corticogenesis. These data identify TBR2 as a major determinant of the INP-specific traits by regulating both genetic and epigenetic pathways.
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Affiliation(s)
- Alessandro Sessa
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute , 20132 Milan, Italy
| | - Ernesto Ciabatti
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute , 20132 Milan, Italy
| | - Daniela Drechsel
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway ,LondonNW7 1AA, UK
| | - Luca Massimino
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute , 20132 Milan, Italy
| | - Gaia Colasante
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute , 20132 Milan, Italy
| | - Serena Giannelli
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute , 20132 Milan, Italy
| | - Takashi Satoh
- Laboratory of Host Defense, Osaka University, Osaka565-0871, Japan
| | - Shizuo Akira
- Laboratory of Host Defense, Osaka University, Osaka565-0871, Japan
| | - Francois Guillemot
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway ,LondonNW7 1AA, UK
| | - Vania Broccoli
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy.,CNR Institute of Neuroscience, 20129 Milan, Italy
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11
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Koinuma S, Takeuchi K, Wada N, Nakamura T. cAMP-induced activation of protein kinase A and p190B RhoGAP mediates down-regulation of TC10 activity at the plasma membrane and neurite outgrowth. Genes Cells 2017; 22:953-967. [PMID: 29072354 DOI: 10.1111/gtc.12538] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 09/08/2017] [Indexed: 12/14/2022]
Abstract
Cyclic AMP plays a pivotal role in neurite growth. During outgrowth, a trafficking system supplies membrane at growth cones. However, the cAMP-induced signaling leading to the regulation of membrane trafficking remains unknown. TC10 is a Rho family GTPase that is essential for specific types of vesicular trafficking. Recent studies have shown a role of TC10 in neurite growth in NGF-treated PC12 cells. Here, we investigated a mechanical linkage between cAMP and TC10 in neuritogenesis. Plasmalemmal TC10 activity decreased abruptly after cAMP addition in neuronal cells. TC10 was locally inactivated at extending neurite tips in cAMP-treated PC12 cells. TC10 depletion led to a decrease in cAMP-induced neurite outgrowth. Constitutively active TC10 could not rescue this growth reduction, supporting our model for a role of GTP hydrolysis of TC10 in neuritogenesis by accelerating vesicle fusion. The cAMP-induced TC10 inactivation was mediated by PKA. Considering cAMP-induced RhoA inactivation, we found that p190B, but not p190A, mediated inactivation of TC10 and RhoA. Upon cAMP treatment, p190B was recruited to the plasma membrane. STEF depletion and Rac1-N17 expression reduced cAMP-induced TC10 inactivation. Together, the PKA-STEF-Rac1-p190B pathway leading to inactivation of TC10 and RhoA at the plasma membrane plays an important role in cAMP-induced neurite outgrowth.
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Affiliation(s)
- Shingo Koinuma
- Division of Biosignaling, Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Chiba, Japan
| | - Kohei Takeuchi
- Division of Biosignaling, Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Chiba, Japan
| | - Naoyuki Wada
- Department of Applied Biological Science, Tokyo University of Science, Noda, Chiba, Japan
| | - Takeshi Nakamura
- Division of Biosignaling, Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Chiba, Japan
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12
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DDX3 Modulates Neurite Development via Translationally Activating an RNA Regulon Involved in Rac1 Activation. J Neurosci 2017; 36:9792-804. [PMID: 27656019 DOI: 10.1523/jneurosci.4603-15.2016] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 08/01/2016] [Indexed: 01/23/2023] Open
Abstract
UNLABELLED The RNA helicase DDX3 is a component of neuronal granules, and its gene mutations are linked to intellectual disability (ID). Here we demonstrate that DDX3 depletion in neurons impairs neurite development by downregulating Rac1 level and activation. Moreover, DDX3 activates the translation of functionally coherent mRNAs involved in Rac1 activation including Rac1 Among the DDX3 regulon, Prkaca encodes the catalytic subunit of PKA, a potential activator of Rac1 in neurons. DDX3-modulated PKAcα and Rac1 expression tunes the strength of PKA-Rac1 signaling and thereby contributes to neurite outgrowth and dendritic spine formation. Inhibition of DDX3 activity or expression in neonatal mice impaired dendritic outgrowth and spine formation of hippocampal neurons, echoing neuronal deficits underling DDX3 mutation-associated ID. Finally, we provide evidence that DDX3 activates local protein synthesis through a 5' UTR-dependent mechanism in neurons. The novel DDX3 regulon may conduct a spatial and temporal control of Rac1 signaling to regulate neurite development. SIGNIFICANCE STATEMENT DDX3X mutations are linked to intellectual disability (ID). We provide first evidence that DDX3 is required for neurite outgrowth and dendritic spine formation in vitro and in vivo We identified a DDX3 regulon constituting functionally cohesive mRNAs involved in Rac1 signaling, which contributes to DDX3-modulated neurite development. Inhibition or ablation of DDX3 in vivo shortened neurite lengths and impaired dendritic spine formation in hippocampal neurons, reflecting the prevalence of ID-associated DDX3X mutations in the helicase domain. Mechanistically, DDX3 activates local protein synthesis of mRNAs sharing similar 5' UTR structures and therefore controls Rac1 signaling strength in neurites.
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13
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Leon J, Sakumi K, Castillo E, Sheng Z, Oka S, Nakabeppu Y. 8-Oxoguanine accumulation in mitochondrial DNA causes mitochondrial dysfunction and impairs neuritogenesis in cultured adult mouse cortical neurons under oxidative conditions. Sci Rep 2016; 6:22086. [PMID: 26912170 PMCID: PMC4766534 DOI: 10.1038/srep22086] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 02/05/2016] [Indexed: 01/20/2023] Open
Abstract
Oxidative stress and mitochondrial dysfunction are implicated in aging-related neurodegenerative disorders. 8-Oxoguanine (8-oxoG), a common oxidised base lesion, is often highly accumulated in brains from patients with neurodegenerative disorders. MTH1 hydrolyses 8-oxo-2'-deoxyguanosine triphosphate (8-oxo-dGTP) to 8-oxo-dGMP and pyrophosphate in nucleotide pools, while OGG1 excises 8-oxoG paired with cytosine in DNA, thereby minimising the accumulation of 8-oxoG in DNA. Mth1/Ogg1-double knockout (TO-DKO) mice are highly susceptible to neurodegeneration under oxidative conditions and show increased accumulation of 8-oxoG in mitochondrial DNA (mtDNA) in neurons, suggesting that 8-oxoG accumulation in mtDNA causes mitochondrial dysfunction. Here, we evaluated the contribution of MTH1 and OGG1 to the prevention of mitochondrial dysfunction during neuritogenesis in vitro. We isolated cortical neurons from adult wild-type and TO-DKO mice and maintained them with or without antioxidants for 2 to 5 days and then examined neuritogenesis. In the presence of antioxidants, both TO-DKO and wild-type neurons exhibited efficient neurite extension and arborisation. However, in the absence of antioxidants, the accumulation of 8-oxoG in mtDNA of TO-DKO neurons was increased resulting in mitochondrial dysfunction. Cells also exhibited poor neurite outgrowth with decreased complexity of neuritic arborisation, indicating that MTH1 and OGG1 are essential for neuritogenesis under oxidative conditions.
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Affiliation(s)
- Julio Leon
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Kunihiko Sakumi
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Erika Castillo
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Zijing Sheng
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Sugako Oka
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yusaku Nakabeppu
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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14
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Regulating Rac in the nervous system: molecular function and disease implication of Rac GEFs and GAPs. BIOMED RESEARCH INTERNATIONAL 2015; 2015:632450. [PMID: 25879033 PMCID: PMC4388020 DOI: 10.1155/2015/632450] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/06/2015] [Indexed: 12/11/2022]
Abstract
Rho family GTPases, including RhoA, Rac1, and Cdc42 as the most studied members, are master regulators of actin cytoskeletal organization. Rho GTPases control various aspects of the nervous system and are associated with a number of neuropsychiatric and neurodegenerative diseases. The activity of Rho GTPases is controlled by two families of regulators, guanine nucleotide exchange factors (GEFs) as the activators and GTPase-activating proteins (GAPs) as the inhibitors. Through coordinated regulation by GEFs and GAPs, Rho GTPases act as converging signaling molecules that convey different upstream signals in the nervous system. So far, more than 70 members of either GEFs or GAPs of Rho GTPases have been identified in mammals, but only a small subset of them have well-known functions. Thus, characterization of important GEFs and GAPs in the nervous system is crucial for the understanding of spatiotemporal dynamics of Rho GTPase activity in different neuronal functions. In this review, we summarize the current understanding of GEFs and GAPs for Rac1, with emphasis on the molecular function and disease implication of these regulators in the nervous system.
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15
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Llavero F, Urzelai B, Osinalde N, Gálvez P, Lacerda HM, Parada LA, Zugaza JL. Guanine nucleotide exchange factor αPIX leads to activation of the Rac 1 GTPase/glycogen phosphorylase pathway in interleukin (IL)-2-stimulated T cells. J Biol Chem 2015; 290:9171-82. [PMID: 25694429 DOI: 10.1074/jbc.m114.608414] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Indexed: 01/27/2023] Open
Abstract
Recently, we have reported that the active form of Rac 1 GTPase binds to the glycogen phosphorylase muscle isoform (PYGM) and modulates its enzymatic activity leading to T cell proliferation. In the lymphoid system, Rac 1 and in general other small GTPases of the Rho family participate in the signaling cascades that are activated after engagement of the T cell antigen receptor. However, little is known about the IL-2-dependent Rac 1 activator molecules. For the first time, a signaling pathway leading to the activation of Rac 1/PYGM in response to IL-2-stimulated T cell proliferation is described. More specifically, αPIX, a known guanine nucleotide exchange factor for the small GTPases of the Rho family, preferentially Rac 1, mediates PYGM activation in Kit 225 T cells stimulated with IL-2. Using directed mutagenesis, phosphorylation of αPIX Rho-GEF serines 225 and 488 is required for activation of the Rac 1/PYGM pathway. IL-2-stimulated serine phosphorylation was corroborated in Kit 225 T cells cultures. A parallel pharmacological and genetic approach identified PKCθ as the serine/threonine kinase responsible for αPIX serine phosphorylation. The phosphorylated state of αPIX was required to activate first Rac 1 and subsequently PYGM. These results demonstrate that the IL-2 receptor activation, among other early events, leads to activation of PKCθ. To activate Rac 1 and consequently PYGM, PKCθ phosphorylates αPIX in T cells. The biological significance of this PKCθ/αPIX/Rac 1 GTPase/PYGM signaling pathway seems to be the control of different cellular responses such as migration and proliferation.
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Affiliation(s)
- Francisco Llavero
- From the Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country, 48940 Leioa, Spain, the Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, Building 205, 48170 Zamudio, Spain
| | - Bakarne Urzelai
- From the Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country, 48940 Leioa, Spain
| | - Nerea Osinalde
- the Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark
| | - Patricia Gálvez
- the Pharmascience Division, Technological Park of Health Sciences, Avda. de la Ciencia, s/n 18100 Armilla, Granada, Spain
| | - Hadriano M Lacerda
- the Department of Biomedical Sciences and Human Oncology, Unit of Cancer Epidemiology, Università degli Studi di Torino, 10124 Torino, Italy
| | - Luis A Parada
- the Instituto de Patología Experimental, Universidad Nacional de Salta, 4400 Salta, Argentina, and
| | - José L Zugaza
- From the Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country, 48940 Leioa, Spain, the Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, Building 205, 48170 Zamudio, Spain, the IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao, Spain
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16
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Pampaloni F, Richa R, Ansari N, Stelzer EHK. Live spheroid formation recorded with light sheet-based fluorescence microscopy. Methods Mol Biol 2015; 1251:43-57. [PMID: 25391793 DOI: 10.1007/978-1-4939-2080-8_3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We provide a detailed protocol for a three-dimensional long-term live imaging of cellular spheroids with light sheet-based fluorescence microscopy. The protocol allows the recording of all phases of spheroid formation in three dimensions, including cell proliferation, aggregation, and compaction. We employ the human hepatic cell line HepaRG transfected with the fusion protein H2B-GFP, i.e., a fluorescing histone. The protocol allows monitoring the effect of drugs or toxicants.
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Affiliation(s)
- Francesco Pampaloni
- Physical Biology Group, Buchmann Institute for Molecular Life Sciences (BMLS), Goethe Universität Frankfurt am Main, Max-von-Laue-Str. 15, Frankfurt am Main, D-60438, Germany,
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17
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Goto A, Kamioka Y, Matsuda M. PKA modulation of Rac in neuronal cells. Front Cell Neurosci 2014; 8:321. [PMID: 25352782 PMCID: PMC4196561 DOI: 10.3389/fncel.2014.00321] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 09/24/2014] [Indexed: 12/20/2022] Open
Affiliation(s)
- Akihiro Goto
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University Kyoto, Japan
| | - Yuji Kamioka
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University Kyoto, Japan
| | - Michiyuki Matsuda
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University Kyoto, Japan
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18
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The guanine nucleotide exchange factor Tiam1: A Janus-faced molecule in cellular signaling. Cell Signal 2014; 26:483-91. [DOI: 10.1016/j.cellsig.2013.11.034] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 11/26/2013] [Indexed: 11/22/2022]
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19
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Oldach L, Zhang J. Genetically encoded fluorescent biosensors for live-cell visualization of protein phosphorylation. ACTA ACUST UNITED AC 2014; 21:186-97. [PMID: 24485761 DOI: 10.1016/j.chembiol.2013.12.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Revised: 11/22/2013] [Accepted: 12/10/2013] [Indexed: 11/30/2022]
Abstract
Fluorescence-based, genetically encodable biosensors are widely used tools for real-time analysis of biological processes. Over the last few decades, the number of available genetically encodable biosensors and the types of processes they can monitor have increased rapidly. Here, we aim to introduce the reader to general principles and practices in biosensor development and highlight ways in which biosensors can be used to illuminate outstanding questions of biological function. Specifically, we focus on sensors developed for monitoring kinase activity and use them to illustrate some common considerations for biosensor design. We describe several uses to which kinase and second-messenger biosensors have been put, and conclude with considerations for the use of biosensors once they are developed. Overall, as fluorescence-based biosensors continue to diversify and improve, we expect them to continue to be widely used as reliable and fruitful tools for gaining deeper insights into cellular and organismal function.
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Affiliation(s)
- Laurel Oldach
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 307 Hunterian Building, 725 North Wolfe Street, Baltimore, MD 21205, USA
| | - Jin Zhang
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 307 Hunterian Building, 725 North Wolfe Street, Baltimore, MD 21205, USA; The Solomon H. Snyder Department of Neuroscience, Department of Oncology, The Johns Hopkins University School of Medicine, 307 Hunterian Building, 725 North Wolfe Street, Baltimore, MD 21205, USA.
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20
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Gpr126 functions in Schwann cells to control differentiation and myelination via G-protein activation. J Neurosci 2014; 33:17976-85. [PMID: 24227709 DOI: 10.1523/jneurosci.1809-13.2013] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The myelin sheath surrounding axons ensures that nerve impulses travel quickly and efficiently, allowing for the proper function of the vertebrate nervous system. We previously showed that the adhesion G-protein-coupled receptor (aGPCR) Gpr126 is essential for peripheral nervous system myelination, although the molecular mechanisms by which Gpr126 functions were incompletely understood. aGPCRs are a significantly understudied protein class, and it was unknown whether Gpr126 couples to G-proteins. Here, we analyze Dhh(Cre);Gpr126(fl/fl) conditional mutants, and show that Gpr126 functions in Schwann cells (SCs) for radial sorting of axons and myelination. Furthermore, we demonstrate that elevation of cAMP levels or protein kinase A activation suppresses myelin defects in Gpr126 mouse mutants and that cAMP levels are reduced in conditional Gpr126 mutant peripheral nerve. Finally, we show that GPR126 directly increases cAMP by coupling to heterotrimeric G-proteins. Together, these data support a model in which Gpr126 functions in SCs for proper development and myelination and provide evidence that these functions are mediated via G-protein-signaling pathways.
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21
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Zhao ZY, Han CG, Liu JT, Wang CL, Wang Y, Cheng LY. TIAM2 Enhances Non-small Cell Lung Cancer Cell Invasion and Motility. Asian Pac J Cancer Prev 2013; 14:6305-9. [DOI: 10.7314/apjcp.2013.14.11.6305] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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22
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Fujita A, Koinuma S, Yasuda S, Nagai H, Kamiguchi H, Wada N, Nakamura T. GTP hydrolysis of TC10 promotes neurite outgrowth through exocytic fusion of Rab11- and L1-containing vesicles by releasing exocyst component Exo70. PLoS One 2013; 8:e79689. [PMID: 24223996 PMCID: PMC3817099 DOI: 10.1371/journal.pone.0079689] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Accepted: 09/23/2013] [Indexed: 11/24/2022] Open
Abstract
The use of exocytosis for membrane expansion at nerve growth cones is critical for neurite outgrowth. TC10 is a Rho family GTPase that is essential for specific types of vesicular trafficking to the plasma membrane. Recent studies have shown that TC10 and its effector Exo70, a component of the exocyst tethering complex, contribute to neurite outgrowth. However, the molecular mechanisms of the neuritogenesis-promoting functions of TC10 remain to be established. Here, we propose that GTP hydrolysis of vesicular TC10 near the plasma membrane promotes neurite outgrowth by accelerating vesicle fusion by releasing Exo70. Using Förster resonance energy transfer (FRET)-based biosensors, we show that TC10 activity at the plasma membrane decreased at extending growth cones in hippocampal neurons and nerve growth factor (NGF)-treated PC12 cells. In neuronal cells, TC10 activity at vesicles was higher than its activity at the plasma membrane, and TC10-positive vesicles were found to fuse to the plasma membrane in NGF-treated PC12 cells. Therefore, activity of TC10 at vesicles is presumed to be inactivated near the plasma membrane during neuronal exocytosis. Our model is supported by functional evidence that constitutively active TC10 could not rescue decrease in NGF-induced neurite outgrowth induced by TC10 depletion. Furthermore, TC10 knockdown experiments and colocalization analyses confirmed the involvement of Exo70 in TC10-mediated trafficking in neuronal cells. TC10 frequently resided on vesicles containing Rab11, which is a key regulator of recycling pathways and implicated in neurite outgrowth. In growth cones, most of the vesicles containing the cell adhesion molecule L1 had TC10. Exocytosis of Rab11- and L1-positive vesicles may play a central role in TC10-mediated neurite outgrowth. The combination of this study and our previous work on the role of TC10 in EGF-induced exocytosis in HeLa cells suggests that the signaling machinery containing TC10 proposed here may be broadly used for exocytosis.
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Affiliation(s)
- Akane Fujita
- Division of Biosignaling, Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Chiba, Japan
| | - Shingo Koinuma
- Division of Biosignaling, Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Chiba, Japan
| | - Sayaka Yasuda
- Division of Biosignaling, Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Chiba, Japan
| | - Hiroyuki Nagai
- Division of Biosignaling, Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Chiba, Japan
| | - Hiroyuki Kamiguchi
- Laboratory for Neuronal Growth Mechanism, RIKEN Brain Science Institute, Wako, Saitama, Japan
| | - Naoyuki Wada
- Department of Applied Biological Science, Tokyo University of Science, Noda, Chiba, Japan
| | - Takeshi Nakamura
- Division of Biosignaling, Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Chiba, Japan
- * E-mail:
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23
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Goto A, Sumiyama K, Kamioka Y, Nakasyo E, Ito K, Iwasaki M, Enomoto H, Matsuda M. GDNF and endothelin 3 regulate migration of enteric neural crest-derived cells via protein kinase A and Rac1. J Neurosci 2013; 33:4901-12. [PMID: 23486961 PMCID: PMC6618995 DOI: 10.1523/jneurosci.4828-12.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 01/22/2013] [Accepted: 01/25/2013] [Indexed: 11/21/2022] Open
Abstract
Enteric neural crest-derived cells (ENCCs) migrate from the anterior foregut in a rostrocaudal direction to colonize the entire gastrointestinal tract and to form the enteric nervous system. Genetic approaches have identified many signaling molecules regulating the migration of ENCCs; however, it remains elusive how the activities of the signaling molecules are regulated spatiotemporally during migration. In this study, transgenic mice expressing biosensors based on Förster resonance energy transfer were generated to video the activity changes of the signaling molecules in migrating ENCCs. In an organ culture of embryonic day 11.25 (E11.25) to E13 guts, ENCCs at the rostral wavefront migrated as a cellular chain faster than the following ENCCs that formed a network. The faster-migrating cells at the wavefront exhibited lower protein kinase A (PKA) activity than did the slower-migrating trailing cells. The activities of Rac1 and Cdc42 exhibited an inverse correlation with the PKA activity, and PKA activation decreased the Rac1 activity and migration velocity. PKA activity in ENCCs was correlated positively with the distribution of GDNF and inversely with the distribution of endothelin 3 (ET-3). Accordingly, PKA was activated by GDNF and inhibited by ET-3 in cultured ENCCs. Finally, although the JNK and ERK pathways were previously reported to control the migration of ENCCs, we did not find any correlation of JNK or ERK activity with the migration velocities. These results suggest that external cues regulate the migration of ENCCs by controlling PKA activity, but not ERK or JNK activity, and argue for the importance of live imaging of signaling molecule activities in developing organs.
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Affiliation(s)
- Akihiro Goto
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, and
| | - Kenta Sumiyama
- Division of Population Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Yuji Kamioka
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8315, Japan
| | - Eiji Nakasyo
- Life & Industrial Products Development Department 1, R&D Division, Olympus Corporation, Hachioji, Tokyo 192-8507, Japan, and
| | - Keisuke Ito
- Laboratory for Neuronal Differentiation and Regeneration, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Mitsuhiro Iwasaki
- Laboratory for Neuronal Differentiation and Regeneration, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Hideki Enomoto
- Laboratory for Neuronal Differentiation and Regeneration, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Michiyuki Matsuda
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, and
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8315, Japan
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24
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Miller MB, Yan Y, Eipper BA, Mains RE. Neuronal Rho GEFs in synaptic physiology and behavior. Neuroscientist 2013; 19:255-73. [PMID: 23401188 DOI: 10.1177/1073858413475486] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In the mammalian brain, the majority of excitatory synapses are housed in micron-sized dendritic protrusions called spines, which can undergo rapid changes in shape and number in response to increased or decreased synaptic activity. These dynamic alterations in dendritic spines require precise control of the actin cytoskeleton. Within spines, multidomain Rho guanine nucleotide exchange factors (Rho GEFs) coordinate activation of their target Rho GTPases by a variety of pathways. In this review, we focus on the handful of disease-related Rho GEFs (Kalirin; Trio; Tiam1; P-Rex1,2; RasGRF1,2; Collybistin) localized at synapses and known to affect electrophysiology, spine morphology, and animal behavior. The goal is to integrate structure/function studies with measurements of synaptic function and behavioral phenotypes in animal models.
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Affiliation(s)
- Megan B Miller
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030-3401, USA
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25
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Abstract
1-42 β-Amyloid (Aβ(1-42)) peptide is a key molecule involved in the development of Alzheimer's disease. Some of its effects are manifested at the neuronal morphological level. These morphological changes involve loss of neurites due to cytoskeleton alterations. However, the mechanism of Aβ(1-42) peptide activation of the neurodegenerative program is still poorly understood. Here, Aβ(1-42) peptide-induced transduction of cellular death signals through the phosphatidylinositol 3-kinase (PI3K)/phosphoinositol-dependent kinase (PDK)/novel protein kinase C (nPKC)/Rac 1 axis is described. Furthermore, pharmacological inhibition of PDK1 and nPKC activities blocks Rac 1 activation and neuronal cell death. Our results provide insights into an unsuspected connection between PDK1, nPKCs and Rac 1 in the same signal-transduction pathway and points out nPKCs and Rac 1 as potential therapeutic targets to block the toxic effects of Aβ(1-42) peptide in neurons.
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26
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Tang AT, Campbell WB, Nithipatikom K. ROCK1 feedback regulation of the upstream small GTPase RhoA. Cell Signal 2012; 24:1375-80. [PMID: 22430126 DOI: 10.1016/j.cellsig.2012.03.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 03/01/2012] [Accepted: 03/04/2012] [Indexed: 10/28/2022]
Abstract
Rho-associated coiled-coil containing protein kinase 1 (ROCK1) is a key downstream effector of the small GTPase RhoA. Targeting ROCK1 has shown promising clinical potential in cancer, cardioprotection, hypertension, diabetes, neuronal regeneration, and stem cell biology. General working hypothesis in previous studies has centered on the function of ROCK1 as a downstream sequence in the RhoA signaling pathway. In this study, the effects of the direct inhibition of ROCK1 on the activity of upstream RhoA and Rac1 were examined using a combined pharmacological and genetic approach. We report an intriguing mechanism by which the inhibition of ROCK1 indirectly diminishes the activity of upstream RhoA through the stimulation of Tiam1-induced Rac1 activity. This novel feedback mechanism, in which ROCK1 mediates upstream Rac1 and RhoA activity, offers considerable insight into the diverse effects of ROCK1 on the functional balance of the Rho family of small GTPases, which regulates actin cytoskeleton reorganization processes and the resulting overall behavior of cells.
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Affiliation(s)
- Alan T Tang
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI 53226, United States
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27
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Optogenetic reporters: Fluorescent protein-based genetically encoded indicators of signaling and metabolism in the brain. PROGRESS IN BRAIN RESEARCH 2012; 196:235-63. [PMID: 22341329 DOI: 10.1016/b978-0-444-59426-6.00012-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Fluorescent protein technology has evolved to include genetically encoded biosensors that can monitor levels of ions, metabolites, and enzyme activities as well as protein conformation and even membrane voltage. They are well suited to live-cell microscopy and quantitative analysis, and they can be used in multiple imaging modes, including one- or two-photon fluorescence intensity or lifetime microscopy. Although not nearly complete, there now exists a substantial set of genetically encoded reporters that can be used to monitor many aspects of neuronal and glial biology, and these biosensors can be used to visualize synaptic transmission and activity-dependent signaling in vitro and in vivo. In this review, we present an overview of design strategies for engineering biosensors, including sensor designs using circularly permuted fluorescent proteins and using fluorescence resonance energy transfer between fluorescent proteins. We also provide examples of indicators that sense small ions (e.g., pH, chloride, zinc), metabolites (e.g., glutamate, glucose, ATP, cAMP, lipid metabolites), signaling pathways (e.g., G protein-coupled receptors, Rho GTPases), enzyme activities (e.g., protein kinase A, caspases), and reactive species. We focus on examples where these genetically encoded indicators have been applied to brain-related studies and used with live-cell fluorescence microscopy.
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28
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Jeon CY, Moon MY, Kim JH, Kim HJ, Kim JG, Li Y, Jin JK, Kim PH, Kim HC, Meier KE, Kim YS, Park JB. Control of neurite outgrowth by RhoA inactivation. J Neurochem 2011; 120:684-98. [PMID: 22035369 DOI: 10.1111/j.1471-4159.2011.07564.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
cAMP induces neurite outgrowth in the rat pheochromocytoma cell line 12 (PC12). In particular, di-butyric cAMP (db-cAMP) induces a greater number of primary processes with shorter length than the number induced by nerve growth factor (NGF). db-cAMP up- and down-regulates GTP-RhoA levels in PC12 cells in a time-dependent manner. Tat-C3 toxin stimulates neurite outgrowth, whereas lysophosphatidic acid (LPA) and constitutively active (CA)-RhoA reduce neurite outgrowth, suggesting that RhoA inactivation is essential for the neurite outgrowth from PC12 cells stimulated by cAMP. In this study, the mechanism by which RhoA is inactivated in response to cAMP was examined. db-cAMP induces phosphorylation of RhoA and augments the binding of RhoA with Rho guanine nucleotide dissociation inhibitor (GDI). Moreover, RhoA (S188D) mimicking phosphorylated RhoA induces greater neurite outgrowth than RhoA (S188A) mimicking dephosphorylated form does. Additionally, db-cAMP increases GTP-Rap1 levels, and dominant negative (DN)-Rap1 and DN-Rap-dependent RhoGAP (ARAP3) block neurite outgrowth induced by db-cAMP. DN-p190RhoGAP and the Src inhibitor PP2 suppress neurite outgrowth, whereas transfection of c-Src and p190RhoGAP cDNAs synergistically stimulate neurite outgrowth. Taken together, RhoA is inactivated by phosphorylation of itself, by p190RhoGAP which is activated by Src, and by ARAP3 which is activated by Rap1 during neurite outgrowth from PC12 cells in response to db-cAMP.
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Affiliation(s)
- Chan-Young Jeon
- Department of Biochemistry, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, South Korea
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