1
|
Yang LJ, Wu W, Jiang WR, Zhu CL, Yao ZH. Upregulation of RasGRF1 ameliorates spatial cognitive dysfunction in mice after chronic cerebral hypoperfusion. Aging (Albany NY) 2023; 15:2999-3020. [PMID: 37053022 DOI: 10.18632/aging.204654] [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: 02/08/2023] [Accepted: 03/31/2023] [Indexed: 04/14/2023]
Abstract
Chronic cerebral hypoperfusion (CCH)-mediated cognitive impairment is a serious problem worldwide. However, given its complexity, the underlying mechanisms by which CCH induces cognitive dysfunction remain unclear, resulting in a lack of effective treatments. In this study, we aimed to determine whether changes in the expression of RasGRF1, an important protein associated with cognition and synaptic plasticity, underlie the associated impairments in cognition after CCH. We found that RasGRF1 levels markedly decreased following CCH. Through prediction and validation studies, we observed that miRNA-323-3p was upregulated after CCH and could bind to the 3'-untranslated region of Rasgrf1 mRNA and regulate its expression in vitro. Moreover, the inhibition of miRNA-323-3p upregulated Rasgrf1 expression in the hippocampus after CCH, which was reversed by Rasgrf1 siRNA. This suggests that miRNA-323-3p is an important regulator of Rasgrf1. The Morris water maze and Y maze tests showed that miRNA-323-3p inhibition and Rasgrf1 upregulation improved spatial learning and memory, and electrophysiological measurements revealed deficits in long-term potentiation after CCH that were reversed by Rasgrf1 upregulation. Dendritic spine density and mature mushroom spine density were also improved after miRNA-323-3p inhibition and Rasgrf1 upregulation. Furthermore, Rasgrf1 upregulation by miRNA-323-3p inhibition improved dendritic spine density and mature mushroom spine density and ameliorated the deterioration of synapses and postsynaptic density. Overall, RasGRF1 regulation attenuated cognitive impairment, helped maintain structural and functional synaptic plasticity, and prevented synapse deterioration after CCH. These results suggest that Rasgrf1 downregulation by miRNA-323-3p plays an important role in cognitive impairment after CCH. Thus, RasGRF1 and miRNA-323-3p may represent potential therapeutic targets for cognitive impairment after CCH.
Collapse
Affiliation(s)
- Li-Jie Yang
- Department of Geriatrics, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Wei Wu
- Department of Clinical Laboratory, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Wan-Rong Jiang
- Department of Geriatrics, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Cheng-Liang Zhu
- Department of Clinical Laboratory, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Zhao-Hui Yao
- Department of Geriatrics, Renmin Hospital of Wuhan University, Wuhan 430060, China
| |
Collapse
|
2
|
Kozlova A, Zhang S, Kotlar AV, Jamison B, Zhang H, Shi S, Forrest MP, McDaid J, Cutler DJ, Epstein MP, Zwick ME, Pang ZP, Sanders AR, Warren ST, Gejman PV, Mulle JG, Duan J. Loss of function of OTUD7A in the schizophrenia- associated 15q13.3 deletion impairs synapse development and function in human neurons. Am J Hum Genet 2022; 109:1500-1519. [PMID: 35931052 PMCID: PMC9388388 DOI: 10.1016/j.ajhg.2022.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 06/27/2022] [Indexed: 02/06/2023] Open
Abstract
Identifying causative gene(s) within disease-associated large genomic regions of copy-number variants (CNVs) is challenging. Here, by targeted sequencing of genes within schizophrenia (SZ)-associated CNVs in 1,779 SZ cases and 1,418 controls, we identified three rare putative loss-of-function (LoF) mutations in OTU deubiquitinase 7A (OTUD7A) within the 15q13.3 deletion in cases but none in controls. To tie OTUD7A LoF with any SZ-relevant cellular phenotypes, we modeled the OTUD7A LoF mutation, rs757148409, in human induced pluripotent stem cell (hiPSC)-derived induced excitatory neurons (iNs) by CRISPR-Cas9 engineering. The mutant iNs showed a ∼50% decrease in OTUD7A expression without undergoing nonsense-mediated mRNA decay. The mutant iNs also exhibited marked reduction of dendritic complexity, density of synaptic proteins GluA1 and PSD-95, and neuronal network activity. Congruent with the neuronal phenotypes in mutant iNs, our transcriptomic analysis showed that the set of OTUD7A LoF-downregulated genes was enriched for those relating to synapse development and function and was associated with SZ and other neuropsychiatric disorders. These results suggest that OTUD7A LoF impairs synapse development and neuronal function in human neurons, providing mechanistic insight into the possible role of OTUD7A in driving neuropsychiatric phenotypes associated with the 15q13.3 deletion.
Collapse
Affiliation(s)
- Alena Kozlova
- Center for Psychiatric Genetics, NorthShore University HealthSystem, Evanston, IL 60201, USA
| | - Siwei Zhang
- Center for Psychiatric Genetics, NorthShore University HealthSystem, Evanston, IL 60201, USA; Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, IL 60637, USA
| | - Alex V Kotlar
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA; Pillar Biosciences Inc., Natick, MA 01760, USA
| | - Brendan Jamison
- Center for Psychiatric Genetics, NorthShore University HealthSystem, Evanston, IL 60201, USA
| | - Hanwen Zhang
- Center for Psychiatric Genetics, NorthShore University HealthSystem, Evanston, IL 60201, USA
| | - Serena Shi
- Winston Churchill High School, Potomac, MD 20854, USA
| | - Marc P Forrest
- Department of Neuroscience, Northwestern University, Chicago, IL 60611, USA; Center for Autism and Neurodevelopment, Northwestern University, Chicago, IL 60611, USA
| | - John McDaid
- Department of Neurosurgery, NorthShore University HealthSystem, Evanston, IL 60201, USA
| | - David J Cutler
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Michael P Epstein
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Michael E Zwick
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA; Senior Vice President for Research, Rutgers University, New Brunswick, NJ 08901, USA
| | - Zhiping P Pang
- Department of Neuroscience and Cell Biology, Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
| | - Alan R Sanders
- Center for Psychiatric Genetics, NorthShore University HealthSystem, Evanston, IL 60201, USA; Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, IL 60637, USA
| | - Stephen T Warren
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Pablo V Gejman
- Center for Psychiatric Genetics, NorthShore University HealthSystem, Evanston, IL 60201, USA; Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, IL 60637, USA
| | - Jennifer G Mulle
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Psychiatry, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ 08901, USA
| | - Jubao Duan
- Center for Psychiatric Genetics, NorthShore University HealthSystem, Evanston, IL 60201, USA; Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, IL 60637, USA.
| |
Collapse
|
3
|
Goto K, Pissaloux D, Fraitag S, Amini M, Vaucher R, Tirode F, de la Fouchardière A. RASGRF1-rearranged Cutaneous Melanocytic Neoplasms With Spitzoid Cytomorphology: A Clinicopathologic and Genetic Study of 3 Cases. Am J Surg Pathol 2022; 46:655-663. [PMID: 34799483 DOI: 10.1097/pas.0000000000001839] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Spitz neoplasms, according to 2018 WHO Blue Book, are morphologically defined by spindled and/or epithelioid melanocytes and genetically by either HRAS mutations or kinase gene fusions. The terminology "spitzoid" refers to lesions with similar morphology but with alternate or undefined genetic anomalies. Herein, we present 3 melanocytic neoplasms with a spitzoid cytomorphology, variable nuclear atypia, and harboring undescribed fusions involving RASGRF1. Two cases presented as unpigmented papules on the heel of a 26-year-old female (case 1) and the forearm of a 13-year-old boy (case 2). They were classified as low-grade melanocytomas (WHO 2018). The third case appeared as a pigmented ulcer on the sole of a 72-year-old female (case 3) that displayed diagnostic features of an invasive melanoma (Breslow thickness 6 mm, Clark level V). A wide skin reexcision identified an epidermotropic metastasis, and sentinel lymph node biopsy displayed multiple subcapsular metastatic deposits. RNA sequencing revealed CD63::RASGRF1, EHBP1::RASGRF1, and ABCC2::RASGRF1 fusions in cases 1 to 3, respectively. They were confirmed by a RASGRF1 break-apart fluorescence in situ hybridization technique. Translocations of RASGRF1, a gene coding a guanine nucleotide exchange factor but not a kinase, have rarely been reported in tumors. While all these cases showed spitzoid cytomorphology, it is too early to tell if they are true Spitz neoplasms as currently defined.
Collapse
Affiliation(s)
- Keisuke Goto
- Department of Pathology, Tokyo Metropolitan Cancer and Infectious Disease Center Komagome Hospital
- Department of Pathology, Itabashi Central Clinical Laboratory
- Department of Anatomic Pathology, Tokyo Medical University, Tokyo
- Department of Diagnostic Pathology, Shizuoka Cancer Center Hospital, Sunto
- Department of Diagnostic Pathology and Cytology, Osaka International Cancer Institute
- Department of Diagnostic Pathology, Osaka National Hospital, Osaka
- Department of Dermatology, Hyogo Cancer Center, Akashi, Japan
| | - Daniel Pissaloux
- Departments of Biopathology
- Sword University Claude Bernard Lyon I, INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Center of Lyon, Equipe Labellisée Ligue contre le Cancer, Lyon
| | - Sylvie Fraitag
- Department of Pathology, Necker-Enfants Malades Hospital
- Department of Pathology, Paris Hospitals - Public Assistance, Paris, France
| | | | - Richard Vaucher
- Plastic Reconstructive and Aesthetic Surgery, Center Léon Bérard
| | - Franck Tirode
- Departments of Biopathology
- Sword University Claude Bernard Lyon I, INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Center of Lyon, Equipe Labellisée Ligue contre le Cancer, Lyon
| | - Arnaud de la Fouchardière
- Departments of Biopathology
- Sword University Claude Bernard Lyon I, INSERM 1052, CNRS 5286, Centre Léon Bérard, Cancer Research Center of Lyon, Equipe Labellisée Ligue contre le Cancer, Lyon
| |
Collapse
|
4
|
Del Sol-Fernández S, Martínez-Vicente P, Gomollón-Zueco P, Castro-Hinojosa C, Gutiérrez L, Fratila RM, Moros M. Magnetogenetics: remote activation of cellular functions triggered by magnetic switches. NANOSCALE 2022; 14:2091-2118. [PMID: 35103278 PMCID: PMC8830762 DOI: 10.1039/d1nr06303k] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/13/2021] [Indexed: 05/03/2023]
Abstract
During the last decade, the possibility to remotely control intracellular pathways using physical tools has opened the way to novel and exciting applications, both in basic research and clinical applications. Indeed, the use of physical and non-invasive stimuli such as light, electricity or magnetic fields offers the possibility of manipulating biological processes with spatial and temporal resolution in a remote fashion. The use of magnetic fields is especially appealing for in vivo applications because they can penetrate deep into tissues, as opposed to light. In combination with magnetic actuators they are emerging as a new instrument to precisely manipulate biological functions. This approach, coined as magnetogenetics, provides an exclusive tool to study how cells transform mechanical stimuli into biochemical signalling and offers the possibility of activating intracellular pathways connected to temperature-sensitive proteins. In this review we provide a critical overview of the recent developments in the field of magnetogenetics. We discuss general topics regarding the three main components for magnetic field-based actuation: the magnetic fields, the magnetic actuators and the cellular targets. We first introduce the main approaches in which the magnetic field can be used to manipulate the magnetic actuators, together with the most commonly used magnetic field configurations and the physicochemical parameters that can critically influence the magnetic properties of the actuators. Thereafter, we discuss relevant examples of magneto-mechanical and magneto-thermal stimulation, used to control stem cell fate, to activate neuronal functions, or to stimulate apoptotic pathways, among others. Finally, although magnetogenetics has raised high expectations from the research community, to date there are still many obstacles to be overcome in order for it to become a real alternative to optogenetics for instance. We discuss some controversial aspects related to the insufficient elucidation of the mechanisms of action of some magnetogenetics constructs and approaches, providing our opinion on important challenges in the field and possible directions for the upcoming years.
Collapse
Affiliation(s)
- Susel Del Sol-Fernández
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain.
| | - Pablo Martínez-Vicente
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain.
| | - Pilar Gomollón-Zueco
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain.
| | - Christian Castro-Hinojosa
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain.
| | - Lucía Gutiérrez
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain.
- Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Spain
- Departamento de Química Analítica, Universidad de Zaragoza, Zaragoza 50009, Spain
| | - Raluca M Fratila
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain.
- Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Spain
- Departamento de Química Orgánica, Universidad de Zaragoza, C/Pedro Cerbuna 12, Zaragoza 50009, Spain
| | - María Moros
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain.
- Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Spain
| |
Collapse
|
5
|
Umeda K, Negishi M, Katoh H. RasGRF1 mediates brain-derived neurotrophic factor-induced axonal growth in primary cultured cortical neurons. Biochem Biophys Rep 2018; 17:56-64. [PMID: 30582008 PMCID: PMC6295856 DOI: 10.1016/j.bbrep.2018.11.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 11/29/2018] [Indexed: 12/01/2022] Open
Abstract
The appropriate development and regulation of neuronal morphology are important to establish functional neuronal circuits and enable higher brain function of the central nervous system. R-Ras, a member of the Ras family of small GTPases, plays crucial roles in the regulation of axonal morphology, including outgrowth, branching, and guidance. GTP-bound activated R-Ras reorganizes actin filaments and microtubules through interactions with its downstream effectors, leading to the precise control of axonal morphology. However, little is known about the upstream regulatory mechanisms for R-Ras activation in neurons. In this study, we found that brain-derived neurotrophic factor (BDNF) has a positive effect on endogenous R-Ras activation and promotes R-Ras-mediated axonal growth. RNA interference knockdown and overexpression experiments revealed that RasGRF1, a guanine nucleotide exchange factor (GEF) for R-Ras, is involved in BDNF-induced R-Ras activation and the promotion of axonal growth. Phosphorylation of RasGRF1 by protein kinase A at Ser916/898 is needed for the full activation of its GEF activity and to facilitate Ras signaling. We observed that BDNF treatment markedly increased this phosphorylation. Our results suggest that BDNF is one of the critical extrinsic regulators for R-Ras activation, and that RasGRF1 is an intrinsic key mediator for BDNF-induced R-Ras activation and R-Ras-mediated axonal morphological regulation.
Collapse
Affiliation(s)
- Kentaro Umeda
- Laboratory of Molecular Neurobiology, Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Manabu Negishi
- Laboratory of Molecular Neurobiology, Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.,Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hironori Katoh
- Laboratory of Molecular Neurobiology, Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.,Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| |
Collapse
|
6
|
TrkB Regulates N-Methyl-D-Aspartate Receptor Signaling by Uncoupling and Recruiting the Brain-Specific Guanine Nucleotide Exchange Factor, RasGrf1. J Mol Neurosci 2018; 67:97-110. [DOI: 10.1007/s12031-018-1214-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/11/2018] [Indexed: 01/26/2023]
|
7
|
Unravelling the Mechanism of TrkA-Induced Cell Death by Macropinocytosis in Medulloblastoma Daoy Cells. Mol Cell Biol 2016; 36:2596-611. [PMID: 27503856 DOI: 10.1128/mcb.00255-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/29/2016] [Indexed: 12/26/2022] Open
Abstract
Macropinocytosis is a normal cellular process by which cells internalize extracellular fluids and nutrients from their environment and is one strategy that Ras-transformed pancreatic cancer cells use to increase uptake of amino acids to meet the needs of rapid growth. Paradoxically, in non-Ras transformed medulloblastoma brain tumors, we have shown that expression and activation of the receptor tyrosine kinase TrkA overactivates macropinocytosis, resulting in the catastrophic disintegration of the cell membrane and in tumor cell death. The molecular basis of this uncontrolled form of macropinocytosis has not been previously understood. Here, we demonstrate that the overactivation of macropinocytosis is caused by the simultaneous activation of two TrkA-mediated pathways: (i) inhibition of RhoB via phosphorylation at Ser(185) by casein kinase 1, which relieves actin stress fibers, and (ii) FRS2-scaffolded Src and H-Ras activation of RhoA, which stimulate actin reorganization and the formation of lamellipodia. Since catastrophic macropinocytosis results in brain tumor cell death, improved understanding of the mechanisms involved will facilitate future efforts to reprogram tumors, even those resistant to apoptosis, to die.
Collapse
|
8
|
Kurakin A, Bredesen DE. Dynamic self-guiding analysis of Alzheimer's disease. Oncotarget 2016; 6:14092-122. [PMID: 26041885 PMCID: PMC4546454 DOI: 10.18632/oncotarget.4221] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 04/08/2015] [Indexed: 01/25/2023] Open
Abstract
We applied a self-guiding evolutionary algorithm to initiate the synthesis of the Alzheimer's disease-related data and literature. A protein interaction network associated with amyloid-beta precursor protein (APP) and a seed model that treats Alzheimer's disease as progressive dysregulation of APP-associated signaling were used as dynamic “guides” and structural “filters” in the recursive search, analysis, and assimilation of data to drive the evolution of the seed model in size, detail, and complexity. Analysis of data and literature across sub-disciplines and system-scale discovery platforms suggests a key role of dynamic cytoskeletal connectivity in the stability, plasticity, and performance of multicellular networks and architectures. Chronic impairment and/or dysregulation of cell adhesions/synapses, cytoskeletal networks, and/or reversible epithelial-to-mesenchymal-like transitions, which enable and mediate the stable and coherent yet dynamic and reconfigurable multicellular architectures, may lead to the emergence and persistence of the disordered, wound-like pockets/microenvironments of chronically disconnected cells. Such wound-like microenvironments support and are supported by pro-inflammatory, pro-secretion, de-differentiated cellular phenotypes with altered metabolism and signaling. The co-evolution of wound-like microenvironments and their inhabitants may lead to the selection and stabilization of degenerated cellular phenotypes, via acquisition of epigenetic modifications and mutations, which eventually result in degenerative disorders such as cancer and Alzheimer's disease.
Collapse
Affiliation(s)
- Alexei Kurakin
- Mary S. Easton Center for Alzheimer's Disease Research, Department of Neurology, University of California, Los Angeles, CA, USA
| | - Dale E Bredesen
- Mary S. Easton Center for Alzheimer's Disease Research, Department of Neurology, University of California, Los Angeles, CA, USA.,Buck Institute for Research on Aging, Novato, CA, USA
| |
Collapse
|
9
|
Ceriani M, Amigoni L, D'Aloia A, Berruti G, Martegani E. The deubiquitinating enzyme UBPy/USP8 interacts with TrkA and inhibits neuronal differentiation in PC12 cells. Exp Cell Res 2015; 333:49-59. [PMID: 25662281 DOI: 10.1016/j.yexcr.2015.01.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 01/20/2015] [Accepted: 01/28/2015] [Indexed: 11/19/2022]
Abstract
The tropomyosin-related kinase (Trk) family of receptor tyrosine kinases controls synaptic function, plasticity and sustains differentiation, morphology, and neuronal cell survival. Understanding Trk receptors down-regulation and recycling is a crucial step to point out sympathetic and sensory neuron function and survival. PC12 cells derived from pheochromocytoma of the rat adrenal medulla have been widely used as a model system for studies of neuronal differentiation as they respond to nerve growth factor (NGF) with a dramatic change in phenotype and acquire a number of properties characteristic of sympathetic neurons. In this study we demonstrated that in PC12 cells the TrkA receptor interacts with the deubiquitinating enzyme USP8/UBPy in a NGF-dependent manner and that it is deubiquitinated in vivo and in vitro by USP8. USP8 overexpression blocked NGF-induced neurites outgrowth while the overexpression of the catalytically inactive mutant USP8/UBPy(C748A) caused a marked increase of cell differentiation. Localization and biochemical experiments have point out that USP8 and TrkA partially co-localize in endosomes after NGF stimulation. Finally we have studied the role played by USP8 on TrkA turnover; using specific siRNA for USP8 we found that USP8 knockdown increases TrkA half-life, suggesting that the deubiquitinating activity of USP8 promotes TrkA degradation.
Collapse
Affiliation(s)
- Michela Ceriani
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy.
| | - Loredana Amigoni
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy.
| | - Alessia D'Aloia
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy.
| | - Giovanna Berruti
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy.
| | - Enzo Martegani
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy.
| |
Collapse
|
10
|
Darcy MJ, Trouche S, Jin SX, Feig LA. Age-dependent role for Ras-GRF1 in the late stages of adult neurogenesis in the dentate gyrus. Hippocampus 2014; 24:315-25. [PMID: 24174283 DOI: 10.1002/hipo.22225] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/08/2013] [Accepted: 10/22/2013] [Indexed: 01/08/2023]
Abstract
The dentate gyrus of the hippocampus plays a pivotal role in pattern separation, a process required for the behavioral task of contextual discrimination. One unique feature of the dentate gyrus that contributes to pattern separation is adult neurogenesis, where newly born neurons play a distinct role in neuronal circuitry. Moreover,the function of neurogenesis in this brain region differs in adolescent and adult mice. The signaling mechanisms that differentially regulate the distinct steps of adult neurogenesis in adolescence and adulthood remain poorly understood. We used mice lacking RASGRF1(GRF1), a calcium-dependent exchange factor that regulates synaptic plasticity and participates in contextual discrimination performed by mice, to test whether GRF1 plays a role in adult neurogenesis.We show Grf1 knockout mice begin to display a defect in neurogenesis at the onset of adulthood (~2 months of age), when wild-type mice first acquire the ability to distinguish between closely related contexts. At this age, young hippocampal neurons in Grf1 knockout mice display severely reduced dendritic arborization. By 3 months of age, new neuron survival is also impaired. BrdU labeling of new neurons in 2-month-old Grf1 knockout mice shows they begin to display reduced survival between 2 and 3 weeks after birth, just as new neurons begin to develop complex dendritic morphology and transition into using glutamatergic excitatory input. Interestingly, GRF1 expression appears in new neurons at the developmental stage when GRF1 loss begins to effect neuronal function. In addition, we induced a similar loss of new hippocampal neurons by knocking down expression of GRF1 solely in new neurons by injecting retrovirus that express shRNA against GRF1 into the dentate gyrus. Together, these findings show that GRF1 expressed in new neurons promotes late stages of adult neurogenesis. Overall our findings show GRF1 to be an age-dependent regulator of adult hippocampal neurogenesis, which contributes to ability of mice to distinguish closely related contexts.
Collapse
|
11
|
Expression and genomic imprinting of the porcine Rasgrf1 gene. Gene 2014; 536:357-61. [DOI: 10.1016/j.gene.2013.11.069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 11/22/2013] [Accepted: 11/23/2013] [Indexed: 11/23/2022]
|