1
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Engeln M, Fox ME, Chandra R, Choi EY, Nam H, Qadir H, Thomas SS, Rhodes VM, Turner MD, Herman RJ, Calarco CA, Lobo MK. Transcriptome profiling of the ventral pallidum reveals a role for pallido-thalamic neurons in cocaine reward. Mol Psychiatry 2022; 27:3980-3991. [PMID: 35764708 PMCID: PMC9722585 DOI: 10.1038/s41380-022-01668-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 05/28/2022] [Accepted: 06/08/2022] [Indexed: 02/06/2023]
Abstract
Psychostimulant exposure alters the activity of ventral pallidum (VP) projection neurons. However, the molecular underpinnings of these circuit dysfunctions are unclear. We used RNA-sequencing to reveal alterations in the transcriptional landscape of the VP that are induced by cocaine self-administration in mice. We then probed gene expression in select VP neuronal subpopulations to isolate a circuit associated with cocaine intake. Finally, we used both overexpression and CRISPR-mediated knockdown to test the role of a gene target on cocaine-mediated behaviors as well as dendritic spine density. Our results showed that a large proportion (55%) of genes associated with structural plasticity were changed 24 h following cocaine intake. Among them, the transcription factor Nr4a1 (Nuclear receptor subfamily 4, group A, member 1, or Nur77) showed high expression levels. We found that the VP to mediodorsal thalamus (VP → MDT) projection neurons specifically were recapitulating this increase in Nr4a1 expression. Overexpressing Nr4a1 in VP → MDT neurons enhanced drug-seeking and drug-induced reinstatement, while Nr4a1 knockdown prevented self-administration acquisition and subsequent cocaine-mediated behaviors. Moreover, we showed that Nr4a1 negatively regulated spine dynamics in this specific cell subpopulation. Together, our study identifies for the first time the transcriptional mechanisms occurring in VP in drug exposure. Our study provides further understanding on the role of Nr4a1 in cocaine-related behaviors and identifies the crucial role of the VP → MDT circuit in drug intake and relapse-like behaviors.
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Affiliation(s)
- Michel Engeln
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA.
- Univ. Bordeaux, CNRS, INCIA, UMR 5287, F-33000, Bordeaux, France.
| | - Megan E Fox
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Anesthesiology & Perioperative Medicine, Penn State College of Medicine, Hershey, PA, USA
| | - Ramesh Chandra
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Eric Y Choi
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Hyungwoo Nam
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Houman Qadir
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Shavin S Thomas
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Victoria M Rhodes
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Makeda D Turner
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Rae J Herman
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Cali A Calarco
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mary Kay Lobo
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA.
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2
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Zhang C, Ni C, Lu H. Polo-Like Kinase 2: From Principle to Practice. Front Oncol 2022; 12:956225. [PMID: 35898867 PMCID: PMC9309260 DOI: 10.3389/fonc.2022.956225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 06/14/2022] [Indexed: 11/21/2022] Open
Abstract
Polo-like kinase (PLK) 2 is an evolutionarily conserved serine/threonine kinase that shares the n-terminal kinase catalytic domain and the C-terminal Polo Box Domain (PBD) with other members of the PLKs family. In the last two decades, mounting studies have focused on this and tried to clarify its role in many aspects. PLK2 is essential for mitotic centriole replication and meiotic chromatin pairing, synapsis, and crossing-over in the cell cycle; Loss of PLK2 function results in cell cycle disorders and developmental retardation. PLK2 is also involved in regulating cell differentiation and maintaining neural homeostasis. In the process of various stimuli-induced stress, including oxidative and endoplasmic reticulum, PLK2 may promote survival or apoptosis depending on the intensity of stimulation and the degree of cell damage. However, the role of PLK2 in immunity to viral infection has been studied far less than that of other family members. Because PLK2 is extensively and deeply involved in normal physiological functions and pathophysiological mechanisms of cells, its role in diseases is increasingly being paid attention to. The effect of PLK2 in inhibiting hematological tumors and fibrotic diseases, as well as participating in neurodegenerative diseases, has been gradually recognized. However, the research results in solid organ tumors show contradictory results. In addition, preliminary studies using PLK2 as a disease predictor and therapeutic target have yielded some exciting and promising results. More research will help people better understand PLK2 from principle to practice.
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Affiliation(s)
- Chuanyong Zhang
- Hepatobiliary Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
- Key Laboratory of Liver Transplantation, Chinese Academy of Medical Sciences, Nanjing, China
| | - Chuangye Ni
- Hepatobiliary Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
- Key Laboratory of Liver Transplantation, Chinese Academy of Medical Sciences, Nanjing, China
| | - Hao Lu
- Hepatobiliary Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
- Key Laboratory of Liver Transplantation, Chinese Academy of Medical Sciences, Nanjing, China
- *Correspondence: Hao Lu,
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3
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Kant TA, Newe M, Winter L, Hoffmann M, Kämmerer S, Klapproth E, Künzel K, Kühnel MP, Neubert L, El-Armouche A, Künzel SR. Genetic Deletion of Polo-Like Kinase 2 Induces a Pro-Fibrotic Pulmonary Phenotype. Cells 2021; 10:617. [PMID: 33799608 PMCID: PMC8001503 DOI: 10.3390/cells10030617] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/04/2021] [Accepted: 03/09/2021] [Indexed: 02/07/2023] Open
Abstract
Pulmonary fibrosis is the chronic-progressive replacement of healthy lung tissue by extracellular matrix, leading to the destruction of the alveolar architecture and ultimately death. Due to limited pathophysiological knowledge, causal therapies are still missing and consequently the prognosis is poor. Thus, there is an urgent clinical need for models to derive effective therapies. Polo-like kinase 2 (PLK2) is an emerging regulator of fibroblast function and fibrosis. We found a significant downregulation of PLK2 in four different entities of human pulmonary fibrosis. Therefore, we characterized the pulmonary phenotype of PLK2 knockout (KO) mice. Isolated pulmonary PLK2 KO fibroblasts displayed a pronounced myofibroblast phenotype reflected by increased expression of αSMA, reduced proliferation rates and enhanced ERK1/2 and SMAD2/3 phosphorylation. In PLK2 KO, the expression of the fibrotic cytokines osteopontin and IL18 was elevated compared to controls. Histological analysis of PLK2 KO lungs revealed early stage remodeling in terms of alveolar wall thickening, increased alveolar collagen deposition and myofibroblast foci. Our results prompt further investigation of PLK2 function in pulmonary fibrosis and suggest that the PLK2 KO model displays a genetic predisposition towards pulmonary fibrosis, which could be leveraged in future research on this topic.
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Affiliation(s)
- Theresa A. Kant
- Institute of Pharmacology and Toxicology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany; (T.A.K.); (M.N.); (L.W.); (M.H.); (S.K.); (E.K.); (K.K.)
| | - Manja Newe
- Institute of Pharmacology and Toxicology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany; (T.A.K.); (M.N.); (L.W.); (M.H.); (S.K.); (E.K.); (K.K.)
| | - Luise Winter
- Institute of Pharmacology and Toxicology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany; (T.A.K.); (M.N.); (L.W.); (M.H.); (S.K.); (E.K.); (K.K.)
| | - Maximilian Hoffmann
- Institute of Pharmacology and Toxicology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany; (T.A.K.); (M.N.); (L.W.); (M.H.); (S.K.); (E.K.); (K.K.)
| | - Susanne Kämmerer
- Institute of Pharmacology and Toxicology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany; (T.A.K.); (M.N.); (L.W.); (M.H.); (S.K.); (E.K.); (K.K.)
| | - Erik Klapproth
- Institute of Pharmacology and Toxicology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany; (T.A.K.); (M.N.); (L.W.); (M.H.); (S.K.); (E.K.); (K.K.)
| | - Karolina Künzel
- Institute of Pharmacology and Toxicology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany; (T.A.K.); (M.N.); (L.W.); (M.H.); (S.K.); (E.K.); (K.K.)
| | - Mark P. Kühnel
- Institute of Pathology, Hannover Medical School, 30625 Hannover, Germany; (M.P.K.); (L.N.)
| | - Lavinia Neubert
- Institute of Pathology, Hannover Medical School, 30625 Hannover, Germany; (M.P.K.); (L.N.)
| | - Ali El-Armouche
- Institute of Pharmacology and Toxicology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany; (T.A.K.); (M.N.); (L.W.); (M.H.); (S.K.); (E.K.); (K.K.)
| | - Stephan R. Künzel
- Institute of Pharmacology and Toxicology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany; (T.A.K.); (M.N.); (L.W.); (M.H.); (S.K.); (E.K.); (K.K.)
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4
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Nam Y, Joo B, Lee JY, Han KM, Ryu KY, Koh YH, Kim J, Koo JW, We YM, Hoe HS. ALWPs Improve Cognitive Function and Regulate Aβ Plaque and Tau Hyperphosphorylation in a Mouse Model of Alzheimer's Disease. Front Mol Neurosci 2019; 12:192. [PMID: 31474828 PMCID: PMC6707392 DOI: 10.3389/fnmol.2019.00192] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 07/24/2019] [Indexed: 01/21/2023] Open
Abstract
Recently, we reported that ALWPs, which we developed by combining Liuwei Dihuang pills (LWPs) with antler, regulate the LPS-induced neuroinflammatory response and rescue LPS-induced short- and long-term memory impairment in wild-type (WT) mice. In the present study, we examined the effects of ALWPs on Alzheimer’s disease (AD) pathology and cognitive function in WT mice as well as 5x FAD mice (a mouse model of AD). We found that administration of ALWPs significantly reduced amyloid plaque levels in 5x FAD mice and significantly decreased amyloid β (Aβ) levels in amyloid precursor protein (APP)-overexpressing H4 cells. In addition, ALWPs administration significantly suppressed tau hyperphosphorylation in 5x FAD mice. Oral administration of ALWPs significantly improved long-term memory in scopolamine (SCO)-injected WT mice and 5x FAD mice by altering dendritic spine density. Importantly, ALWPs promoted spinogenesis in primary hippocampal neurons and WT mice and modulated the dendritic spine number in an extracellular signal-regulated kinase (ERK)-dependent manner. Taken together, our results suggest that ALWPs are a candidate therapeutic drug for AD that can modulate amyloid plaque load, tau phosphorylation, and synaptic/cognitive function.
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Affiliation(s)
- Youngpyo Nam
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea
| | - Bitna Joo
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea.,Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, South Korea
| | - Ju-Young Lee
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea
| | - Kyung-Min Han
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea.,Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, South Korea
| | - Ka-Young Ryu
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea
| | - Young Ho Koh
- Center for Biomedical Sciences, Center for Infectious Diseases, Division of Brain Disease, Korea National Institute of Health, Heungdeok-gu, South Korea
| | - Jeongyeon Kim
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea
| | - Ja Wook Koo
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea.,Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, South Korea
| | - Young-Man We
- College of Korean Medicine, Wonkwang University, Iksan, South Korea
| | - Hyang-Sook Hoe
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea.,Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, South Korea
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5
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Sui H, Zhan L, Niu X, Liang L, Li X. The SNK and SPAR signaling pathway changes in hippocampal neurons treated with amyloid-beta peptide in vitro. Neuropeptides 2017; 63:43-48. [PMID: 28400058 DOI: 10.1016/j.npep.2017.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 02/19/2017] [Accepted: 03/16/2017] [Indexed: 11/24/2022]
Abstract
Amyloid-β peptide (Aβ) is believed to be a primary cause of Alzheimer's disease. Many studies have demonstrated that Aβ causes morphological and functional alterations of dendritic spines, leading to synaptic dysfunction, but the effect of Aβ on damage to synaptic functions is not fully understood. Spine-associated Rap guanosine triphosphatase-activating protein (SPAR) is an important regulator of activity-dependent remodeling of synapses and is critically involved in both mature dendritic spine formation and the maintenance of spine maturity. Serum-inducible kinase (SNK) is an activity-inducible member of the polo-like family of serine/threonine kinases. Coordinated regulation of Ras and Rap by SNK is critical for homeostatic plasticity and memory. A previous study in which rats were injected with Aβ1-40 into the hippocampus showed that the SNK and SPAR signaling pathway may play a crucial role in Aβ-induced excitotoxic damage in the central nervous system by regulating synaptic stability. The present study was designed to investigate whether the SNK and SPAR signaling pathway was involved in Aβ-induced neurotoxicity in rat primary neurons. We measured mRNA and protein expression levels of SNK and SPAR in primary hippocampal neurons following Aβ treatment and used RNA interference to knockdown SNK to investigate the underlying mechanism. Expression of SNK and SPAR was altered by Aβ treatment, indicating that the SNK and SPAR signaling pathways may be involved in the damage to dendritic spines in hippocampal neurons induced by Aβ.
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Affiliation(s)
- Hua Sui
- Institute of Basic Research of Integrative Medicine, Dalian Medical University, Dalian 116044, Liaoning, China
| | - Libin Zhan
- The Second Affiliated Hospital of Dalian Medical University, Dalian 116023, Liaoning, China; College of Basic Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, Jiangsu, China.
| | - Xinping Niu
- Department of Cardiology, Dalian Second People's Hospital, Dalian 116011, Liaoning, China
| | - Lina Liang
- Institute of Basic Research of Integrative Medicine, Dalian Medical University, Dalian 116044, Liaoning, China
| | - Xin Li
- Institute of Basic Research of Integrative Medicine, Dalian Medical University, Dalian 116044, Liaoning, China
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6
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Song JM, Sung YM, Nam JH, Yoon H, Chung A, Moffat E, Jung M, Pak DTS, Kim J, Hoe HS. A Mercaptoacetamide-Based Class II Histone Deacetylase Inhibitor Increases Dendritic Spine Density via RasGRF1/ERK Pathway. J Alzheimers Dis 2016; 51:591-604. [PMID: 26890742 DOI: 10.3233/jad-150717] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The accumulation of amyloid-β (Aβ) leads to the loss of dendritic spines and synapses, which is hypothesized to cause cognitive impairments in Alzheimer's disease (AD) patients. In our previous study, we demonstrated that a novel mercaptoacetamide-based class II histone deacetylase inhibitor (HDACI), known as W2, decreased Aβ levels and improved learning and memory in mice. However, the underlying mechanism of this effect is unknown. OBJECTIVE Because dendritic spine formation is associated with cognitive performance, here we investigated whether HDACI W2 regulates dendritic spine density and its molecular mechanism of action. METHODS To examine the effect of HDACI W2 on dendritic spine density, we conducted morphological analysis of dendritic spines using GFP transfection and Golgi staining. In addition, to determine the molecular mechanism of W2 effects on spines, we measured the levels of mRNAs and proteins involved in the Ras signaling pathway using quantitative real-time PCR, immunocytochemistry, and western analysis. RESULTS We found that HDACI W2 altered dendritic spine density and morphology in vitro and in vivo. Additionally, W2 increased the mRNA or protein levels of Ras GRF1 and phospho-ERK. Moreover, knockdown of RasGRF1 and inhibition of ERK activity prevented the W2-mediated spinogenesis in primary hippocampal neurons. CONCLUSION Our Class II-selective HDACI W2 promotes the formation and growth of dendritic spines in a RasGRF1 and ERK dependent manner in primary hippocampal neurons.
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Affiliation(s)
- Jung Min Song
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | - You Me Sung
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | - Jin Han Nam
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Dong-gu, Daegu, Korea
| | - Hyejin Yoon
- Department of Neuroscience, Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Jacksonville, FL, USA
| | - Andrew Chung
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | - Emily Moffat
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | - Mira Jung
- Department of Radiation Medicine, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA
| | - Daniel T S Pak
- Department of Pharmacology, Georgetown University Medical Center, Washington, DC, USA
| | - Jungsu Kim
- Department of Neuroscience, Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Jacksonville, FL, USA
| | - Hyang-Sook Hoe
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA.,Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Dong-gu, Daegu, Korea
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7
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Liu Y, Lacal J, Firtel RA, Kortholt A. Connecting G protein signaling to chemoattractant-mediated cell polarity and cytoskeletal reorganization. Small GTPases 2016; 9:360-364. [PMID: 27715492 PMCID: PMC5997169 DOI: 10.1080/21541248.2016.1235390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The directional movement toward extracellular chemical gradients, a process called chemotaxis, is an important property of cells. Central to eukaryotic chemotaxis is the molecular mechanism by which chemoattractant-mediated activation of G-protein coupled receptors (GPCRs) induces symmetry breaking in the activated downstream signaling pathways. Studies with mainly Dictyostelium and mammalian neutrophils as experimental systems have shown that chemotaxis is mediated by a complex network of signaling pathways. Recently, several labs have used extensive and efficient proteomic approaches to further unravel this dynamic signaling network. Together these studies showed the critical role of the interplay between heterotrimeric G-protein subunits and monomeric G proteins in regulating cytoskeletal rearrangements during chemotaxis. Here we highlight how these proteomic studies have provided greater insight into the mechanisms by which the heterotrimeric G protein cycle is regulated, how heterotrimeric G proteins-induced symmetry breaking is mediated through small G protein signaling, and how symmetry breaking in G protein signaling subsequently induces cytoskeleton rearrangements and cell migration.
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Affiliation(s)
- Youtao Liu
- a Department of Cell Biochemistry , University of Groningen , Groningen , The Netherlands
| | - Jesus Lacal
- b Section of Cell and Developmental Biology, Division of Biological Sciences, University of California , San Diego, La Jolla , CA , USA
| | - Richard A Firtel
- b Section of Cell and Developmental Biology, Division of Biological Sciences, University of California , San Diego, La Jolla , CA , USA
| | - Arjan Kortholt
- a Department of Cell Biochemistry , University of Groningen , Groningen , The Netherlands
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8
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A Gα-Stimulated RapGEF Is a Receptor-Proximal Regulator of Dictyostelium Chemotaxis. Dev Cell 2016; 37:458-72. [PMID: 27237792 DOI: 10.1016/j.devcel.2016.05.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 02/15/2016] [Accepted: 04/29/2016] [Indexed: 12/19/2022]
Abstract
Chemotaxis, or directional movement toward extracellular chemical gradients, is an important property of cells that is mediated through G-protein-coupled receptors (GPCRs). Although many chemotaxis pathways downstream of Gβγ have been identified, few Gα effectors are known. Gα effectors are of particular importance because they allow the cell to distinguish signals downstream of distinct chemoattractant GPCRs. Here we identify GflB, a Gα2 binding partner that directly couples the Dictyostelium cyclic AMP GPCR to Rap1. GflB localizes to the leading edge and functions as a Gα-stimulated, Rap1-specific guanine nucleotide exchange factor required to balance Ras and Rap signaling. The kinetics of GflB translocation are fine-tuned by GSK-3 phosphorylation. Cells lacking GflB display impaired Rap1/Ras signaling and actin and myosin dynamics, resulting in defective chemotaxis. Our observations demonstrate that GflB is an essential upstream regulator of chemoattractant-mediated cell polarity and cytoskeletal reorganization functioning to directly link Gα activation to monomeric G-protein signaling.
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9
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Yang H, Fang L, Zhan R, Hegarty JM, Ren J, Hsiai TK, Gleeson JG, Miller YI, Trejo J, Chi NC. Polo-like kinase 2 regulates angiogenic sprouting and blood vessel development. Dev Biol 2015; 404:49-60. [PMID: 26004360 DOI: 10.1016/j.ydbio.2015.05.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 04/11/2015] [Accepted: 05/12/2015] [Indexed: 02/07/2023]
Abstract
Angiogenesis relies on specialized endothelial tip cells to extend toward guidance cues in order to direct growing blood vessels. Although many of the signaling pathways that control this directional endothelial sprouting are well known, the specific cellular mechanisms that mediate this process remain to be fully elucidated. Here, we show that Polo-like kinase 2 (PLK2) regulates Rap1 activity to guide endothelial tip cell lamellipodia formation and subsequent angiogenic sprouting. Using a combination of high-resolution in vivo imaging of zebrafish vascular development and a human umbilical vein endothelial cell (HUVEC) in vitro cell culture system, we observed that loss of PLK2 function resulted in a reduction in endothelial cell sprouting and migration, whereas overexpression of PLK2 promoted angiogenesis. Furthermore, we discovered that PLK2 may control angiogenic sprouting by binding to PDZ-GEF to regulate RAP1 activity during endothelial cell lamellipodia formation and extracellular matrix attachment. Consistent with these findings, constitutively active RAP1 could rescue the endothelial cell sprouting defects observed in zebrafish and HUVEC PLK2 knockdowns. Overall, these findings reveal a conserved PLK2-RAP1 pathway that is crucial to regulate endothelial tip cell behavior in order to ensure proper vascular development and patterning in vertebrates.
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Affiliation(s)
- Hongbo Yang
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0613J, USA
| | - Longhou Fang
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0613J, USA
| | - Rui Zhan
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0613J, USA
| | - Jeffrey M Hegarty
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0613J, USA
| | - Jie Ren
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0613J, USA
| | - Tzung K Hsiai
- Division of Cardiology, Department of Medicine, School of Medicine, University of California, Los Angeles, CA, USA; Department of Bioengineering, School of Engineering & Applied Science, University of California, Los Angeles, CA, USA
| | - Joseph G Gleeson
- Neurogenetics Laboratory, Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yury I Miller
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0613J, USA
| | - JoAnn Trejo
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Neil C Chi
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0613J, USA; Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
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10
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A tetra(ethylene glycol) derivative of benzothiazole aniline enhances Ras-mediated spinogenesis. J Neurosci 2013; 33:9306-18. [PMID: 23719799 DOI: 10.1523/jneurosci.1615-12.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The tetra(ethylene glycol) derivative of benzothiazole aniline, BTA-EG4, is a novel amyloid-binding small molecule that can penetrate the blood-brain barrier and protect cells from Aβ-induced toxicity. However, the effects of Aβ-targeting molecules on other cellular processes, including those that modulate synaptic plasticity, remain unknown. We report here that BTA-EG4 decreases Aβ levels, alters cell surface expression of amyloid precursor protein (APP), and improves memory in wild-type mice. Interestingly, the BTA-EG4-mediated behavioral improvement is not correlated with LTP, but with increased spinogenesis. The higher dendritic spine density reflects an increase in the number of functional synapses as determined by increased miniature EPSC (mEPSC) frequency without changes in presynaptic parameters or postsynaptic mEPSC amplitude. Additionally, BTA-EG4 requires APP to regulate dendritic spine density through a Ras signaling-dependent mechanism. Thus, BTA-EG4 may provide broad therapeutic benefits for improving neuronal and cognitive function, and may have implications in neurodegenerative disease therapy.
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11
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Abstract
The small GTPase Rap1 contributes to fear learning and cortico-amygdala plasticity by inhibiting glutamate release from cortical neurons, but mechanisms of this inhibition remain unknown. Conversely, L-type calcium channels (LTCCs) become involved in glutamate release after fear learning and LTP induction. Here, we show that Rap1 deletion in mouse primary cortical neurons increases synaptic vesicle exocytosis without altering endocytosis or vesicle pool size in an LTCC-dependent manner. We identify Erk1/2 as the downstream effector of Rap1 and show that its inhibition increases plasma membrane expression of LTCCs near presynaptic terminals. We propose that the Rap1 signaling enables plasticity and fear learning by regulating LTCCs at cortico-amygdala synapses.
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12
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Mammalian target of rapamycin complex 1 activation negatively regulates Polo-like kinase 2-mediated homeostatic compensation following neonatal seizures. Proc Natl Acad Sci U S A 2013; 110:5199-204. [PMID: 23479645 DOI: 10.1073/pnas.1208010110] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Homeostatic plasticity is characterized by compensatory changes in synaptic strength and intrinsic membrane properties in response to chronic changes in neuronal activity. Neonatal seizures are a naturally occurring source of neuronal overactivation and can lead to long-term epilepsy and cognitive deficits. Using a rodent model of hypoxia-induced neonatal seizures that results in a persistent increase in AMPA receptor (AMPAR) function in hippocampal CA1 pyramidal neurons, we aimed to determine whether there was any evidence of an opposing endogenous homeostatic antiepileptic response. Given that this model results in long-term epilepsy, we also examined mechanisms whereby this homeostasis fails. Whole-cell patch-clamp recordings from neurons in slices removed at intervals following seizure onset revealed an initial up-regulation of AMPAR function that was followed by a transient dynamic attenuation of this enhancement by 48-72 h, although AMPAR function was still increased compared with nonseizure control baseline. This secondary down-regulation of enhanced AMPAR function was coincident with a marked transient increase in expression and function of the Polo-like kinase 2 (PLK2), which has previously been implicated in homeostatic down-regulation of neuronal excitability in cell/slice culture models. The effects were transient and at 1 wk AMPAR function once again became up-regulated, simultaneous with a decrease in PLK2 expression and function. This negative regulation was mediated by subacute postseizure increases in mammalian target of rapamycin (mTOR). Application of the mTOR inhibitor rapamycin prevented post-hypoxic seizure impairment of homeostasis, suggesting that homeostatic plasticity mechanisms may be potentially modifiable therapeutic targets in epileptogenesis.
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