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Yao C, Fang X, Ru Q, Li W, Li J, Mehsein Z, Tolias KF, Li L. Tiam1-mediated maladaptive plasticity underlying morphine tolerance and hyperalgesia. Brain 2024; 147:2507-2521. [PMID: 38577773 PMCID: PMC11224607 DOI: 10.1093/brain/awae106] [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: 11/01/2023] [Revised: 03/16/2024] [Accepted: 03/21/2024] [Indexed: 04/06/2024] Open
Abstract
Opioid pain medications, such as morphine, remain the mainstay for treating severe and chronic pain. Prolonged morphine use, however, triggers analgesic tolerance and hyperalgesia (OIH), which can last for a long period after morphine withdrawal. How morphine induces these detrimental side effects remains unclear. Here, we show that morphine tolerance and OIH are mediated by Tiam1-coordinated synaptic structural and functional plasticity in the spinal nociceptive network. Tiam1 is a Rac1 GTPase guanine nucleotide exchange factor that promotes excitatory synaptogenesis by modulating actin cytoskeletal dynamics. We found that prolonged morphine treatment activated Tiam1 in the spinal dorsal horn and Tiam1 ablation from spinal neurons eliminated morphine antinociceptive tolerance and OIH. At the same time, the pharmacological blockade of Tiam1-Rac1 signalling prevented the development and reserved the established tolerance and OIH. Prolonged morphine treatment increased dendritic spine density and synaptic NMDA receptor activity in spinal dorsal horn neurons, both of which required Tiam1. Furthermore, co-administration of the Tiam1 signalling inhibitor NSC23766 was sufficient to abrogate morphine tolerance in chronic pain management. These findings identify Tiam1-mediated maladaptive plasticity in the spinal nociceptive network as an underlying cause for the development and maintenance of morphine tolerance and OIH and provide a promising therapeutic target to reduce tolerance and prolong morphine use in chronic pain management.
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Affiliation(s)
- Changqun Yao
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35025, USA
| | - Xing Fang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Qin Ru
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Health and Kinesiology, School of Physical Education, Jianghan University, Wuhan 430056, China
| | - Wei Li
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35025, USA
| | - Jun Li
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35025, USA
| | - Zeinab Mehsein
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35025, USA
| | - Kimberley F Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lingyong Li
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35025, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
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2
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Hamad MIK, Emerald BS, Kumar KK, Ibrahim MF, Ali BR, Bataineh MF. Extracellular molecular signals shaping dendrite architecture during brain development. Front Cell Dev Biol 2023; 11:1254589. [PMID: 38155836 PMCID: PMC10754048 DOI: 10.3389/fcell.2023.1254589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 11/28/2023] [Indexed: 12/30/2023] Open
Abstract
Proper growth and branching of dendrites are crucial for adequate central nervous system (CNS) functioning. The neuronal dendritic geometry determines the mode and quality of information processing. Any defects in dendrite development will disrupt neuronal circuit formation, affecting brain function. Besides cell-intrinsic programmes, extrinsic factors regulate various aspects of dendritic development. Among these extrinsic factors are extracellular molecular signals which can shape the dendrite architecture during early development. This review will focus on extrinsic factors regulating dendritic growth during early neuronal development, including neurotransmitters, neurotrophins, extracellular matrix proteins, contact-mediated ligands, and secreted and diffusible cues. How these extracellular molecular signals contribute to dendritic growth has been investigated in developing nervous systems using different species, different areas within the CNS, and different neuronal types. The response of the dendritic tree to these extracellular molecular signals can result in growth-promoting or growth-limiting effects, and it depends on the receptor subtype, receptor quantity, receptor efficiency, the animal model used, the developmental time windows, and finally, the targeted signal cascade. This article reviews our current understanding of the role of various extracellular signals in the establishment of the architecture of the dendrites.
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Affiliation(s)
- Mohammad I. K. Hamad
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Kukkala K. Kumar
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Marwa F. Ibrahim
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Bassam R. Ali
- Department of Genetics and Genomics, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Mo’ath F. Bataineh
- Department of Nutrition and Health, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
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3
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Li L, Ru Q, Lu Y, Fang X, Chen G, Saifullah AB, Yao C, Tolias KF. Tiam1 coordinates synaptic structural and functional plasticity underpinning the pathophysiology of neuropathic pain. Neuron 2023; 111:2038-2050.e6. [PMID: 37146610 PMCID: PMC10330505 DOI: 10.1016/j.neuron.2023.04.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 09/27/2022] [Accepted: 04/10/2023] [Indexed: 05/07/2023]
Abstract
Neuropathic pain is a common, debilitating chronic pain condition caused by damage or a disease affecting the somatosensory nervous system. Understanding the pathophysiological mechanisms underlying neuropathic pain is critical for developing new therapeutic strategies to treat chronic pain effectively. Tiam1 is a Rac1 guanine nucleotide exchange factor (GEF) that promotes dendritic and synaptic growth during hippocampal development by inducing actin cytoskeletal remodeling. Here, using multiple neuropathic pain animal models, we show that Tiam1 coordinates synaptic structural and functional plasticity in the spinal dorsal horn via actin cytoskeleton reorganization and synaptic NMDAR stabilization and that these actions are essential for the initiation, transition, and maintenance of neuropathic pain. Furthermore, an antisense oligonucleotides (ASO) targeting spinal Tiam1 persistently alleviate neuropathic pain sensitivity. Our findings suggest that Tiam1-coordinated synaptic functional and structural plasticity underlies the pathophysiology of neuropathic pain and that intervention of Tiam1-mediated maladaptive synaptic plasticity has long-lasting consequences in neuropathic pain management.
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Affiliation(s)
- Lingyong Li
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35025, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Qin Ru
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Department of Health and Kinesiology, School of Physical Education, Jianghan University, Wuhan 430056, China
| | - Yungang Lu
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pain Medicine, Anesthesiology, Critical Care and Pain Medicine Division, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xing Fang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Guanxing Chen
- Department of Pain Medicine, Anesthesiology, Critical Care and Pain Medicine Division, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ali Bin Saifullah
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Changqun Yao
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35025, USA
| | - Kimberley F Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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4
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c-Abl Tyrosine Kinase Is Required for BDNF-Induced Dendritic Branching and Growth. Int J Mol Sci 2023; 24:ijms24031944. [PMID: 36768268 PMCID: PMC9916151 DOI: 10.3390/ijms24031944] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/09/2023] [Accepted: 01/09/2023] [Indexed: 01/20/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) induces activation of the TrkB receptor and several downstream pathways (MAPK, PI3K, PLC-γ), leading to neuronal survival, growth, and plasticity. It has been well established that TrkB signaling regulation is required for neurite formation and dendritic arborization, but the specific mechanism is not fully understood. The non-receptor tyrosine kinase c-Abl is a possible candidate regulator of this process, as it has been implicated in tyrosine kinase receptors' signaling and trafficking, as well as regulation of neuronal morphogenesis. To assess the role of c-Abl in BDNF-induced dendritic arborization, wild-type and c-Abl-KO neurons were stimulated with BDNF, and diverse strategies were employed to probe the function of c-Abl, including the use of pharmacological inhibitors, an allosteric c-Abl activator, and shRNA to downregulates c-Abl expression. Surprisingly, BDNF promoted c-Abl activation and interaction with TrkB receptors. Furthermore, pharmacological c-Abl inhibition and genetic ablation abolished BDNF-induced dendritic arborization and increased the availability of TrkB in the cell membrane. Interestingly, inhibition or genetic ablation of c-Abl had no effect on the classic TrkB downstream pathways. Together, our results suggest that BDNF/TrkB-dependent c-Abl activation is a novel and essential mechanism in TrkB signaling.
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Li J, Jiang X, Li C, Che H, Ling L, Wei Z. Proteomic alteration of endometrial tissues during secretion in polycystic ovary syndrome may affect endometrial receptivity. Clin Proteomics 2022; 19:19. [PMID: 35643455 PMCID: PMC9145147 DOI: 10.1186/s12014-022-09353-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 04/18/2022] [Indexed: 11/10/2022] Open
Abstract
AbstractEmbryo implantation is a complex developmental process that requires coordinated interactions among the embryo, endometrium, and the microenvironment of endometrium factors. Even though the impaired endometrial receptivity of patients with polycystic ovary syndrome (PCOS) is known, understanding of endometrial receptivity is limited. A proteomics study in three patients with PCOS and 3 fertile women was performed to understand the impaired endometrial receptivity in patients with PCOS during luteal phases. Through isobaric tags for relative and absolute quantitation (iTRAQ) analyses, we identified 232 unique proteins involved in the metabolism, inflammation, and cell adhesion molecules. Finally, our results suggested that energy metabolism can affect embryo implantation, whereas inflammation and cell adhesion molecules can affect both endometrial conversion and receptivity. Our results showed that endometrial receptive damage in patients with PCOS is not a single factor. It is caused by many proteins, pathways, systems, and abnormalities, which interact with each other and make endometrial receptive research more difficult.
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Han X, Yuan T, Zhang J, Shi Y, Li D, Dong Y, Fan S. FOXO4 peptide targets myofibroblast ameliorates bleomycin-induced pulmonary fibrosis in mice through ECM-receptor interaction pathway. J Cell Mol Med 2022; 26:3269-3280. [PMID: 35510614 PMCID: PMC9170815 DOI: 10.1111/jcmm.17333] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 03/13/2022] [Accepted: 03/31/2022] [Indexed: 01/10/2023] Open
Abstract
Pulmonary fibrosis (PF) is a progressive interstitial lung disease with limited treatment options. The incidence and prevalence of PF is increasing with age, cell senescence has been proposed as a pathogenic driver, the clearance of senescent cells could improve lung function in PF. FOXO4‐D‐Retro‐Inverso (FOXO4‐DRI), a synthesis peptide, has been reported to selectively kill senescent cells in aged mice. However, it remains unknown if FOXO4‐DRI could clear senescent cells in PF and reverse this disease. In this study, we explored the effect of FOXO4‐DRI on bleomycin (BLM)‐induced PF mouse model. We found that similar as the approved medication Pirfenidone, FOXO4‐DRI decreased senescent cells, downregulated the expression of senescence‐associated secretory phenotype (SASP) and attenuated BLM‐induced morphological changes and collagen deposition. Furthermore, FOXO4‐DRI could increase the percentage of type 2 alveolar epithelial cells (AEC2) and fibroblasts, and decrease the myofibroblasts in bleomycin (BLM)‐induced PF mouse model. Compared with mouse and human lung fibroblast cell lines, FOXO4‐DRI is inclined to kill TGF‐β‐induced myofibroblast in vitro. The inhibited effect of FOXO4‐DRI on myofibroblast lead to a downregulation of extracellular matrix (ECM) receptor interaction pathway in BLM‐induced PF. Above all, FOXO4‐DRI ameliorates BLM‐induced PF in mouse and may be served as a viable therapeutic option for PF.
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Affiliation(s)
- Xiaodan Han
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Peking Union Medical College and Chinese Academy of Medical Science, Tianjin, China.,Department of Radiation Oncology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Tong Yuan
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Peking Union Medical College and Chinese Academy of Medical Science, Tianjin, China
| | - Junling Zhang
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Peking Union Medical College and Chinese Academy of Medical Science, Tianjin, China
| | - Yonggang Shi
- Department of Radiation Oncology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Deguan Li
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Peking Union Medical College and Chinese Academy of Medical Science, Tianjin, China
| | - Yinping Dong
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Peking Union Medical College and Chinese Academy of Medical Science, Tianjin, China
| | - Saijun Fan
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Peking Union Medical College and Chinese Academy of Medical Science, Tianjin, China
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7
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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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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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9
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Duman JG, Blanco FA, Cronkite CA, Ru Q, Erikson KC, Mulherkar S, Saifullah AB, Firozi K, Tolias KF. Rac-maninoff and Rho-vel: The symphony of Rho-GTPase signaling at excitatory synapses. Small GTPases 2022; 13:14-47. [PMID: 33955328 PMCID: PMC9707551 DOI: 10.1080/21541248.2021.1885264] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 01/15/2023] Open
Abstract
Synaptic connections between neurons are essential for every facet of human cognition and are thus regulated with extreme precision. Rho-family GTPases, molecular switches that cycle between an active GTP-bound state and an inactive GDP-bound state, comprise a critical feature of synaptic regulation. Rho-GTPases are exquisitely controlled by an extensive suite of activators (GEFs) and inhibitors (GAPs and GDIs) and interact with many different signalling pathways to fulfill their roles in orchestrating the development, maintenance, and plasticity of excitatory synapses of the central nervous system. Among the mechanisms that control Rho-GTPase activity and signalling are cell surface receptors, GEF/GAP complexes that tightly regulate single Rho-GTPase dynamics, GEF/GAP and GEF/GEF functional complexes that coordinate multiple Rho-family GTPase activities, effector positive feedback loops, and mutual antagonism of opposing Rho-GTPase pathways. These complex regulatory mechanisms are employed by the cells of the nervous system in almost every step of development, and prominently figure into the processes of synaptic plasticity that underlie learning and memory. Finally, misregulation of Rho-GTPases plays critical roles in responses to neuronal injury, such as traumatic brain injury and neuropathic pain, and in neurodevelopmental and neurodegenerative disorders, including intellectual disability, autism spectrum disorder, schizophrenia, and Alzheimer's Disease. Thus, decoding the mechanisms of Rho-GTPase regulation and function at excitatory synapses has great potential for combatting many of the biggest current challenges in mental health.
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Affiliation(s)
- Joseph G. Duman
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Francisco A. Blanco
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Integrative Molecular and Biomedical Science Graduate Program, Baylor College of Medicine, Houston, TX, USA
| | - Christopher A. Cronkite
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
| | - Qin Ru
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kelly C. Erikson
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Ali Bin Saifullah
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Karen Firozi
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kimberley F. Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
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10
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Liaci C, Camera M, Caslini G, Rando S, Contino S, Romano V, Merlo GR. Neuronal Cytoskeleton in Intellectual Disability: From Systems Biology and Modeling to Therapeutic Opportunities. Int J Mol Sci 2021; 22:ijms22116167. [PMID: 34200511 PMCID: PMC8201358 DOI: 10.3390/ijms22116167] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 05/25/2021] [Accepted: 06/04/2021] [Indexed: 02/06/2023] Open
Abstract
Intellectual disability (ID) is a pathological condition characterized by limited intellectual functioning and adaptive behaviors. It affects 1–3% of the worldwide population, and no pharmacological therapies are currently available. More than 1000 genes have been found mutated in ID patients pointing out that, despite the common phenotype, the genetic bases are highly heterogeneous and apparently unrelated. Bibliomic analysis reveals that ID genes converge onto a few biological modules, including cytoskeleton dynamics, whose regulation depends on Rho GTPases transduction. Genetic variants exert their effects at different levels in a hierarchical arrangement, starting from the molecular level and moving toward higher levels of organization, i.e., cell compartment and functions, circuits, cognition, and behavior. Thus, cytoskeleton alterations that have an impact on cell processes such as neuronal migration, neuritogenesis, and synaptic plasticity rebound on the overall establishment of an effective network and consequently on the cognitive phenotype. Systems biology (SB) approaches are more focused on the overall interconnected network rather than on individual genes, thus encouraging the design of therapies that aim to correct common dysregulated biological processes. This review summarizes current knowledge about cytoskeleton control in neurons and its relevance for the ID pathogenesis, exploiting in silico modeling and translating the implications of those findings into biomedical research.
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Affiliation(s)
- Carla Liaci
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
| | - Mattia Camera
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
| | - Giovanni Caslini
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
| | - Simona Rando
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
| | - Salvatore Contino
- Department of Engineering, University of Palermo, Viale delle Scienze Ed. 8, 90128 Palermo, Italy;
| | - Valentino Romano
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze Ed. 16, 90128 Palermo, Italy;
| | - Giorgio R. Merlo
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
- Correspondence: ; Tel.: +39-0116706449; Fax: +39-0116706432
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11
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Ötzkan S, Muller WE, Gibson Wood W, Eckert GP. Effects of 7,8-Dihydroxyflavone on Lipid Isoprenoid and Rho Protein Levels in Brains of Aged C57BL/6 Mice. Neuromolecular Med 2020; 23:130-139. [PMID: 33377988 PMCID: PMC7929957 DOI: 10.1007/s12017-020-08640-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/25/2020] [Indexed: 12/13/2022]
Abstract
Synaptic impairment may be the main cause of cognitive dysfunction in brain aging that is probably due to a reduction in synaptic contact between the axonal buttons and dendritic spines. Rho proteins including the small GTPase Rac1 have become key regulators of neuronal morphogenesis that supports synaptic plasticity. Small Rho- and Ras-GTPases are post-translationally modified by the isoprenoids geranylgeranyl pyrophosphate (GGPP) and farnesyl pyrophosphate (FPP), respectively. For all GTPases, anchoring in the plasma membrane is essential for their activation by guanine nucleotide exchange factors (GEFs). Rac1-specific GEFs include the protein T lymphoma invasion and metastasis 1 (Tiam1). Tiam1 interacts with the TrkB receptor to mediate the brain-derived neurotrophic factor (BDNF)-induced activation of Rac1, resulting in cytoskeletal rearrangement and changes in cellular morphology. The flavonoid 7,8-dihydroxyflavone (7,8-DHF) acts as a highly affine-selective TrkB receptor agonist and causes the dimerization and autophosphorylation of the TrkB receptor and thus the activation of downstream signaling pathways. In the current study, we investigated the effects of 7,8-DHF on cerebral lipid isoprenoid and Rho protein levels in male C57BL/6 mice aged 3 and 23 months. Aged mice were daily treated with 100 mg/kg b.w. 7,8-DHF by oral gavage for 21 days. FPP, GGPP, and cholesterol levels were determined in brain tissue. In the same tissue, the protein content of Tiam1 and TrkB in was measured. The cellular localization of the small Rho-GTPase Rac1 and small Rab-GTPase Rab3A was studied in total brain homogenates and membrane preparations. We report the novel finding that 7,8-DHF restored levels of the Rho proteins Rac1 and Rab3A in membrane preparations isolated from brains of treated aged mice. The selective TrkB agonist 7,8-DHF did not affect BDNF and TrkB levels, but restored Tiam1 levels that were found to be reduced in brains of aged mice. FPP, GGPP, and cholesterol levels were significantly elevated in brains of aged mice but not changed by 7,8-DHF treatment. Hence, 7,8-DHF may be useful as pharmacological tool to treat age-related cognitive dysfunction although the underlying mechanisms need to be elucidated in detail.
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Affiliation(s)
- Sarah Ötzkan
- Department of Pharmacology, Biocenter Niederursel, University of Frankfurt, Goethe-University, Max-von-Laue-St. 9, 60438, Frankfurt, Germany
| | - Walter E Muller
- Department of Pharmacology, Biocenter Niederursel, University of Frankfurt, Goethe-University, Max-von-Laue-St. 9, 60438, Frankfurt, Germany
| | - W Gibson Wood
- Department of Pharmacology, Geriatric Research, Education and Clinical Center, University of Minnesota School of Medicine, VAMC, Minneapolis, MN, 55417, USA
| | - Gunter P Eckert
- Department of Pharmacology, Biocenter Niederursel, University of Frankfurt, Goethe-University, Max-von-Laue-St. 9, 60438, Frankfurt, Germany.
- Institute of Nutritional Sciences, Laboratory for Nutrition in Prevention and Therapy, Justus-Liebig-University of Giessen, Biomedical Research Center Seltersberg (BFS), Schubertstr. 81, 35392, Giessen, Germany.
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12
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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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13
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Balaji Ragunathrao VA, Anwar M, Akhter MZ, Chavez A, Mao DY, Natarajan V, Lakshmikanthan S, Chrzanowska-Wodnicka M, Dudek AZ, Claesson-Welsh L, Kitajewski JK, Wary KK, Malik AB, Mehta D. Sphingosine-1-Phosphate Receptor 1 Activity Promotes Tumor Growth by Amplifying VEGF-VEGFR2 Angiogenic Signaling. Cell Rep 2020; 29:3472-3487.e4. [PMID: 31825830 PMCID: PMC6927555 DOI: 10.1016/j.celrep.2019.11.036] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 09/06/2019] [Accepted: 11/07/2019] [Indexed: 12/24/2022] Open
Abstract
The vascular endothelial growth factor-A (VEGF-A)-VEGFR2 pathway drives tumor vascularization by activating proangiogenic signaling in endothelial cells (ECs). Here, we show that EC-sphingosine-1-phosphate receptor 1 (S1PR1) amplifies VEGFR2-mediated angiogenic signaling to enhance tumor growth. We show that cancer cells induce S1PR1 activity in ECs, and thereby, conditional deletion of S1PR1 in ECs (EC-S1pr1−/− mice) impairs tumor vascularization and growth. Mechanistically, we show that S1PR1 engages the heterotrimeric G-protein Gi, which amplifies VEGF-VEGFR2 signaling due to an increase in the activity of the tyrosine kinase c-Abl1. c-Abl1, by phosphorylating VEGFR2 at tyrosine-951, prolongs VEGFR2 retention on the plasmalemma to sustain Rac1 activity and EC migration. Thus, S1PR1 or VEGFR2 antagonists, alone or in combination, reverse the tumor growth in control mice to the level seen in EC-S1pr1−/− mice. Our findings suggest that blocking S1PR1 activity in ECs has the potential to suppress tumor growth by preventing amplification of VEGF-VEGFR2 signaling. Vijay Avin et al. demonstrate an essential role of endothelial cell (EC)-S1PR1 signaling in amplifying VEGFR2-mediated tumor growth. S1PR1 by Gi and c-Abl1 phosphorylates VEGFR2 at Y951, which retains VEGFR2 at EC plasmalemma, thus enabling EC migration, tumor angiogenesis, and growth.
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Affiliation(s)
- Vijay Avin Balaji Ragunathrao
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Mumtaz Anwar
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Md Zahid Akhter
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Alejandra Chavez
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - De Yu Mao
- Department of Physiology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Viswanathan Natarajan
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA; Department of Medicine, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | | | | | - Arkadiusz Z Dudek
- Department of Medicine, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Lena Claesson-Welsh
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Science for Life Laboratory, Uppsala University, 751 85 Uppsala, Sweden
| | - Jan K Kitajewski
- Department of Physiology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Kishore K Wary
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Asrar B Malik
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Dolly Mehta
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA.
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14
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Multiplexed GTPase and GEF biosensor imaging enables network connectivity analysis. Nat Chem Biol 2020; 16:826-833. [PMID: 32424303 PMCID: PMC7388658 DOI: 10.1038/s41589-020-0542-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 04/06/2020] [Indexed: 12/31/2022]
Abstract
Here we generate fluorescence resonance energy transfer biosensors for guanine exchange factors (GEFs) by inserting a fluorescent protein pair in a structural 'hinge' common to many GEFs. Fluorescent biosensors can map the activation of signaling molecules in space and time, but it has not been possible to quantify how different activation events affect one another or contribute to a specific cell behavior. By imaging the GEF biosensors in the same cells as red-shifted biosensors of Rho GTPases, we can apply partial correlation analysis to parse out the extent to which each GEF contributes to the activation of a specific GTPase in regulating cell movement. Through analysis of spontaneous cell protrusion events, we identify when and where the GEF Asef regulates the GTPases Cdc42 and Rac1 to control cell edge dynamics. This approach exemplifies a powerful means to elucidate the real-time connectivity of signal transduction networks.
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15
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Nikulina E, Gkioka V, Siddiq MM, Mellado W, Hilaire M, Cain CR, Hannila SS, Filbin MT. Myelin-associated glycoprotein inhibits neurite outgrowth through inactivation of the small GTPase Rap1. FEBS Lett 2020; 594:1389-1402. [PMID: 31985825 DOI: 10.1002/1873-3468.13740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 11/05/2022]
Abstract
Rap1 is a small GTPase that has been implicated in dendritic development and plasticity. In this study, we investigated the role of Rap1 in axonal growth and its activation in response to neurotrophins and myelin-associated inhibitors. We report that Rap1 is activated by brain-derived neurotrophic factor and that this activation can be blocked by myelin-associated glycoprotein (MAG) or central nervous system myelin, which also induced increases in Rap1GAP1 levels. In addition, we demonstrate that adenoviral overexpression of Rap1 enhances neurite outgrowth in the presence of MAG and myelin, while inhibition of Rap1 activity through overexpression of Rap1GAP1 blocks neurite outgrowth. These findings suggest that Rap1GAP1 negatively regulates neurite outgrowth, making it a potential therapeutic target to promote axonal regeneration.
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Affiliation(s)
- Elena Nikulina
- Department of Biological Sciences, Hunter College, City University of New York, NY, USA
| | - Vasiliki Gkioka
- Department of Biological Sciences, Hunter College, City University of New York, NY, USA
| | - Mustafa M Siddiq
- Icahn Medical Institute 12-52, Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, NY, USA
| | | | - Melissa Hilaire
- Department of Biological Sciences, Hunter College, City University of New York, NY, USA
| | - Christine R Cain
- Department of Biological Sciences, Hunter College, City University of New York, NY, USA
| | - Sari S Hannila
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Marie T Filbin
- Department of Biological Sciences, Hunter College, City University of New York, NY, USA
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16
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TrkB hyperactivity contributes to brain dysconnectivity, epileptogenesis, and anxiety in zebrafish model of Tuberous Sclerosis Complex. Proc Natl Acad Sci U S A 2020; 117:2170-2179. [PMID: 31932427 PMCID: PMC6995026 DOI: 10.1073/pnas.1910834117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Tuberous Sclerosis Complex (TSC) is a rare genetic disease that manifests with early symptoms, including cortical malformations, childhood epilepsy, and TSC-associated neuropsychiatric disorders (TANDs). Cortical malformations arise during embryonic development and have been linked to childhood epilepsy before, but the underlying mechanisms of this relationship remain insufficiently understood. Zebrafish have emerged as a convenient model to study elementary neurodevelopment; however, without in-depth functional analysis, the Tsc2-deficient zebrafish line cannot be used for studies of TANDs or new drug screening. In this study, we found that the lack of Tsc2 in zebrafish resulted in heterotopias and hyperactivation of the mTorC1 pathway in pallial regions, which are homologous to the mammalian cortex. We observed commissural thinning that was responsible for brain dysconnectivity, recapitulating TSC pathology in human patients. The lack of Tsc2 also delayed axonal development and caused aberrant tract fasciculation, corresponding to the abnormal expression of genes involved in axon navigation. The mutants underwent epileptogenesis that resulted in nonmotor seizures and exhibited increased anxiety-like behavior. We further mapped discrete parameters of locomotor activity to epilepsy-like and anxiety-like behaviors, which were rescued by reducing tyrosine receptor kinase B (TrkB) signaling. Moreover, in contrast to treatment with vigabatrin and rapamycin, TrkB inhibition rescued brain dysconnectivity and anxiety-like behavior. These data reveal that commissural thinning results in the aberrant regulation of anxiety, providing a mechanistic link between brain anatomy and human TANDs. Our findings also implicate TrkB signaling in the complex pathology of TSC and reveal a therapeutic target.
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17
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miR-200a-3p modulates gene expression in comorbid pain and depression: Molecular implication for central sensitization. Brain Behav Immun 2019; 82:230-238. [PMID: 31479730 DOI: 10.1016/j.bbi.2019.08.190] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 08/18/2019] [Accepted: 08/26/2019] [Indexed: 12/20/2022] Open
Abstract
Chronic pain and depression are often comorbid exhibiting common clinical presentations and biological connections related to central nervous system sensitization. Epigenetic regulation of gene expression in the brain plays a crucial role in response to long-lasting stress and chronic pain, and microRNA imbalance in the prefrontal cortex (PFC) might be involved in central sensitization. Male Sprague Dawley rats were subjected to unpredictable chronic mild stress (UCMS) and spared nerve injury (SNI) to initiate depressive-like behavior and chronic pain behavior, respectively. The next-generation sequencing technique was employed to analyze PFC microRNAs in both the UCMS and SNI models. Rats exposed to either UCMS or SNI exhibited both depressive-like and chronic pain behaviors. Five specific microRNAs (miR-10a-5p, miR-182, miR-200a-3p, miR-200b-3p, and miR-429) were simultaneously down-regulated in the depressive-like and chronic pain models after 4 weeks of short-term stress. Gene ontology revealed that the 4-week period of stress enhanced neurogenesis. Only the miR-200a-3p level was continuously elevated under prolonged stress, suggesting roles of reduced neurogenesis, inflammatory activation, disturbed circadian rhythm, lipid metabolism, and insulin secretion in the co-existence of pain and depression. Thus we conclude that miR-200a-3p might be a specific biomarker of central sensitization in chronic pain and depression.
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18
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Kojima H, Rosendale M, Sugiyama Y, Hayashi M, Horiguchi Y, Yoshihara T, Ikegaya Y, Saneyoshi T, Hayashi Y. The role of CaMKII-Tiam1 complex on learning and memory. Neurobiol Learn Mem 2019; 166:107070. [PMID: 31445077 DOI: 10.1016/j.nlm.2019.107070] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/07/2019] [Accepted: 08/20/2019] [Indexed: 11/18/2022]
Abstract
A stimulation inducing long-term potentiation (LTP) of synaptic transmission induces a persistent expansion of dendritic spines, a phenomenon known as structural LTP (sLTP). We previously proposed that the formation of a reciprocally activating kinase-effector complex (RAKEC) between CaMKII and Tiam1, an activator of the small G-protein Rac1, locks CaMKII into an active conformation, which in turn maintains the phosphorylation status of Tiam1. This makes Rac1 persistently active, specifically in the stimulated spine. To understand the significance of the CaMKII-Tiam1 RAKEC in vivo, we generated a Tiam1 mutant knock-in mouse line in which critical residues for CaMKII binding were mutated into alanines. We confirmed the central role of this interaction on sLTP by observing that KI mice showed reduced Rac1 activity, had smaller spines and a diminished sLTP as compared to their wild-type littermates. Moreover, behavioral tests showed that the novel object recognition memory of these animals was impaired. We thus propose that the CaMKII-Tiam1 interaction regulates spine morphology in vivo and is required for memory storage.
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Affiliation(s)
- Hiroto Kojima
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033, Japan; Department of Pharmacology, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan; RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Morgane Rosendale
- Department of Pharmacology, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan; RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Yui Sugiyama
- Department of Pharmacology, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Mariko Hayashi
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Yoko Horiguchi
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Toru Yoshihara
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takeo Saneyoshi
- Department of Pharmacology, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan; RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.
| | - Yasunori Hayashi
- Department of Pharmacology, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan; RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.
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19
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Xu Z, Chen Y, Chen Y. Spatiotemporal Regulation of Rho GTPases in Neuronal Migration. Cells 2019; 8:cells8060568. [PMID: 31185627 PMCID: PMC6627650 DOI: 10.3390/cells8060568] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 06/01/2019] [Accepted: 06/04/2019] [Indexed: 12/17/2022] Open
Abstract
Neuronal migration is essential for the orchestration of brain development and involves several contiguous steps: interkinetic nuclear movement (INM), multipolar–bipolar transition, locomotion, and translocation. Growing evidence suggests that Rho GTPases, including RhoA, Rac, Cdc42, and the atypical Rnd members, play critical roles in neuronal migration by regulating both actin and microtubule cytoskeletal components. This review focuses on the spatiotemporal-specific regulation of Rho GTPases as well as their regulators and effectors in distinct steps during the neuronal migration process. Their roles in bridging extracellular signals and cytoskeletal dynamics to provide optimal structural support to the migrating neurons will also be discussed.
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Affiliation(s)
- Zhenyan Xu
- The Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen 518055, Guangdong, China.
| | - Yuewen Chen
- The Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen 518055, Guangdong, China.
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen 518057, Guangdong, China.
| | - Yu Chen
- The Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen 518055, Guangdong, China.
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen 518057, Guangdong, China.
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20
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Barfield ET, Gourley SL. Prefrontal cortical trkB, glucocorticoids, and their interactions in stress and developmental contexts. Neurosci Biobehav Rev 2018; 95:535-558. [PMID: 30477984 PMCID: PMC6392187 DOI: 10.1016/j.neubiorev.2018.10.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 09/14/2018] [Accepted: 10/23/2018] [Indexed: 02/07/2023]
Abstract
The tropomyosin/tyrosine receptor kinase B (trkB) and glucocorticoid receptor (GR) regulate neuron structure and function and the hormonal stress response. Meanwhile, disruption of trkB and GR activity (e.g., by chronic stress) can perturb neuronal morphology in cortico-limbic regions implicated in stressor-related illnesses like depression. Further, several of the short- and long-term neurobehavioral consequences of stress depend on the developmental timing and context of stressor exposure. We review how the levels and activities of trkB and GR in the prefrontal cortex (PFC) change during development, interact, are modulated by stress, and are implicated in depression. We review evidence that trkB- and GR-mediated signaling events impact the density and morphology of dendritic spines, the primary sites of excitatory synapses in the brain, highlighting effects in adolescents when possible. Finally, we review the role of neurotrophin and glucocorticoid systems in stress-related metaplasticity. We argue that better understanding the long-term effects of developmental stressors on PFC trkB, GR, and related factors may yield insights into risk for chronic, remitting depression and related neuropsychiatric illnesses.
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Affiliation(s)
- Elizabeth T Barfield
- Department of Pediatrics, Emory University, 954 Gatewood Rd. NE, Atlanta, GA, 30329, USA; Graduate Program in Neuroscience, Emory University, 954 Gatewood Rd. NE, Atlanta, GA, 30329, USA; Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd. NE, Atlanta, GA, 30329, USA; Department of Psychiatry and Behavioral Sciences, Emory University, 954 Gatewood Rd. NE, Atlanta, GA, 30329, USA.
| | - Shannon L Gourley
- Department of Pediatrics, Emory University, 954 Gatewood Rd. NE, Atlanta, GA, 30329, USA; Graduate Program in Neuroscience, Emory University, 954 Gatewood Rd. NE, Atlanta, GA, 30329, USA; Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd. NE, Atlanta, GA, 30329, USA; Department of Psychiatry and Behavioral Sciences, Emory University, 954 Gatewood Rd. NE, Atlanta, GA, 30329, USA; Molecular and Systems Pharmacology Program, Emory University, 954 Gatewood Rd. NE, Atlanta, GA, 30329, USA.
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21
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Giza JI, Kim J, Meyer HC, Anastasia A, Dincheva I, Zheng CI, Lopez K, Bains H, Yang J, Bracken C, Liston C, Jing D, Hempstead BL, Lee FS. The BDNF Val66Met Prodomain Disassembles Dendritic Spines Altering Fear Extinction Circuitry and Behavior. Neuron 2018; 99:163-178.e6. [PMID: 29909994 DOI: 10.1016/j.neuron.2018.05.024] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 01/18/2018] [Accepted: 05/15/2018] [Indexed: 11/16/2022]
Abstract
A human variant in the BDNF gene (Val66Met; rs6265) is associated with impaired fear extinction. Using super-resolution imaging, we demonstrate that the BDNF Met prodomain disassembles dendritic spines and eliminates synapses in hippocampal neurons. In vivo, ventral CA1 (vCA1) hippocampal neurons undergo similar morphological changes dependent on their transient co-expression of a SorCS2/p75NTR receptor complex during peri-adolescence. BDNF Met prodomain infusion into the vCA1 during this developmental time frame reduces dendritic spine density and prelimbic (PL) projections, impairing cued fear extinction. Adolescent BdnfMet/Met mice display similar spine and PL innervation deficits. Using fiber photometry, we found that, in wild-type mice, vCA1 neurons projecting to the PL encode extinction by enhancing neural activity in threat anticipation and rapidly subsiding their response. This adaptation is absent in BDNFMet/Met mice. We conclude that the BDNF Met prodomain renders vCA1-PL projection neurons underdeveloped, preventing their capacity for subsequent circuit modulation necessary for fear extinction. VIDEO ABSTRACT.
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Affiliation(s)
- Joanna I Giza
- Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Jihye Kim
- Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Heidi C Meyer
- Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Agustin Anastasia
- Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC-CONICET-Universidad Nacional de Córdoba), Córdoba, Argentina
| | - Iva Dincheva
- Department of Psychiatry, Columbia University, New York, NY 10032, USA
| | - Crystal I Zheng
- Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Katherine Lopez
- Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
| | - Henrietta Bains
- Department of Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - Jianmin Yang
- Department of Medicine, Weill Cornell Medicine, New York, NY 10065, USA; Key Laboratory of Shaanxi Province Department for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, PR China
| | - Clay Bracken
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Conor Liston
- Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
| | - Deqiang Jing
- Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA
| | | | - Francis S Lee
- Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA; Sackler Institute for Developmental Psychobiology, Weill Cornell Medicine, New York, NY 10065, USA.
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22
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Pearn ML, Schilling JM, Jian M, Egawa J, Wu C, Mandyam CD, Fannon-Pavlich MJ, Nguyen U, Bertoglio J, Kodama M, Mahata SK, DerMardirossian C, Lemkuil BP, Han R, Mobley WC, Patel HH, Patel PM, Head BP. Inhibition of RhoA reduces propofol-mediated growth cone collapse, axonal transport impairment, loss of synaptic connectivity, and behavioural deficits. Br J Anaesth 2018; 120:745-760. [PMID: 29576115 PMCID: PMC6200100 DOI: 10.1016/j.bja.2017.12.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/28/2017] [Accepted: 12/26/2017] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Exposure of the developing brain to propofol results in cognitive deficits. Recent data suggest that inhibition of neuronal apoptosis does not prevent cognitive defects, suggesting mechanisms other than neuronal apoptosis play a role in anaesthetic neurotoxicity. Proper neuronal growth during development is dependent upon growth cone morphology and axonal transport. Propofol modulates actin dynamics in developing neurones, causes RhoA-dependent depolymerisation of actin, and reduces dendritic spines and synapses. We hypothesised that RhoA inhibition prevents synaptic loss and subsequent cognitive deficits. The present study tested whether RhoA inhibition with the botulinum toxin C3 (TAT-C3) prevents propofol-induced synapse and neurite loss, and preserves cognitive function. METHODS RhoA activation, growth cone morphology, and axonal transport were measured in neonatal rat neurones (5-7 days in vitro) exposed to propofol. Synapse counts (electron microscopy), dendritic arborisation (Golgi-Cox), and network connectivity were measured in mice (age 28 days) previously exposed to propofol at postnatal day 5-7. Memory was assessed in adult mice (age 3 months) previously exposed to propofol at postnatal day 5-7. RESULTS Propofol increased RhoA activation, collapsed growth cones, and impaired retrograde axonal transport of quantum dot-labelled brain-derived neurotrophic factor, all of which were prevented with TAT-C3. Adult mice previously treated with propofol had decreased numbers of total hippocampal synapses and presynaptic vesicles, reduced hippocampal dendritic arborisation, and infrapyramidal mossy fibres. These mice also exhibited decreased hippocampal-dependent contextual fear memory recall. All anatomical and behavioural changes were prevented with TAT-C3 pre-treatment. CONCLUSION Inhibition of RhoA prevents propofol-mediated hippocampal neurotoxicity and associated cognitive deficits.
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Affiliation(s)
- M L Pearn
- Veterans Affairs San Diego Healthcare System, UCSD, San Diego CA, USA; Department of Anesthesiology, UCSD, San Diego, CA, USA
| | - J M Schilling
- Veterans Affairs San Diego Healthcare System, UCSD, San Diego CA, USA; Department of Anesthesiology, UCSD, San Diego, CA, USA
| | - M Jian
- Veterans Affairs San Diego Healthcare System, UCSD, San Diego CA, USA; Department of Anesthesiology, UCSD, San Diego, CA, USA; Department of Anesthesiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - J Egawa
- Veterans Affairs San Diego Healthcare System, UCSD, San Diego CA, USA; Department of Anesthesiology, UCSD, San Diego, CA, USA
| | - C Wu
- Department of Neurosciences, UCSD, San Diego, CA, USA
| | - C D Mandyam
- Veterans Affairs San Diego Healthcare System, UCSD, San Diego CA, USA; Department of Anesthesiology, UCSD, San Diego, CA, USA
| | - M J Fannon-Pavlich
- Veterans Affairs San Diego Healthcare System, UCSD, San Diego CA, USA; Department of Anesthesiology, UCSD, San Diego, CA, USA
| | - U Nguyen
- Veterans Affairs San Diego Healthcare System, UCSD, San Diego CA, USA; Department of Anesthesiology, UCSD, San Diego, CA, USA
| | - J Bertoglio
- INSERM U749, Institut Gustave Roussy, Universite Paris-sud, Paris, France
| | - M Kodama
- Veterans Affairs San Diego Healthcare System, UCSD, San Diego CA, USA; Department of Anesthesiology, UCSD, San Diego, CA, USA; Metabolic Physiology and Ultrastructural Biology Laboratory, UCSD, San Diego CA, USA; Department of Anesthesiology, National Defense Medical College, Tokorozawa, Saitama, Japan
| | - S K Mahata
- Metabolic Physiology and Ultrastructural Biology Laboratory, UCSD, San Diego CA, USA
| | - C DerMardirossian
- Department of Immunology and Microbial Sciences, TSRI, La Jolla, CA, USA; Department of Cell and Molecular Biology, TSRI, La Jolla, CA, USA
| | - B P Lemkuil
- Department of Anesthesiology, UCSD, San Diego, CA, USA
| | - R Han
- Department of Anesthesiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - W C Mobley
- Department of Neurosciences, UCSD, San Diego, CA, USA
| | - H H Patel
- Veterans Affairs San Diego Healthcare System, UCSD, San Diego CA, USA; Department of Anesthesiology, UCSD, San Diego, CA, USA
| | - P M Patel
- Veterans Affairs San Diego Healthcare System, UCSD, San Diego CA, USA; Department of Anesthesiology, UCSD, San Diego, CA, USA
| | - B P Head
- Veterans Affairs San Diego Healthcare System, UCSD, San Diego CA, USA; Department of Anesthesiology, UCSD, San Diego, CA, USA.
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23
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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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24
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Lai KO, Ip NY. Methods to Study the Signal Transduction of the Surface Receptor Tyrosine Kinase TrkB in Neurons. Methods Mol Biol 2018; 1722:211-222. [PMID: 29264808 DOI: 10.1007/978-1-4939-7553-2_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Receptor tyrosine kinases (RTK) belong to a major class of cell surface receptors that transduce extracellular signals to elicit diverse intracellular responses. Upon binding to specific ligand, the RTKs become dimerized and autophosphorylated at tyrosine residues. This creates binding sites to recruit specific signaling intermediates and hence trigger distinct signaling events. The cellular response to a given RTK may be modified through the regulation of membrane insertion and receptor internalization. Here we use Trk receptor and its ligand, the neurotrophin brain-derived neurotrophic factor (BDNF), as an example to illustrate the approaches (coimmunoprecipitation and biotinylation) to study the surface expression and signal transduction mediated by this class of RTK in the nervous system.
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Affiliation(s)
- Kwok-On Lai
- School of Biomedical Sciences, LKS Faculty of Medicine, State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, SAR, China.
| | - Nancy Y Ip
- Division of Life Science, Molecular Neuroscience Center and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, SAR, China.
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25
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Honda A, Usui H, Sakimura K, Igarashi M. Rufy3 is an adapter protein for small GTPases that activates a Rac guanine nucleotide exchange factor to control neuronal polarity. J Biol Chem 2017; 292:20936-20946. [PMID: 29089386 DOI: 10.1074/jbc.m117.809541] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/25/2017] [Indexed: 01/01/2023] Open
Abstract
RUN and FYVE domain-containing 3 (Rufy3) is an adapter protein for small GTPase proteins and is bound to activated Rap2, a Ras family protein in the developing neuron. Previously, we reported the presence of a rapid cell polarity determination mechanism involving Rufy3, which is likely required for in vivo neuronal development. However, the molecular details of this mechanism are unclear. To this end, here we produced Rufy3 knock-out (Rufy3-KO) mice to study the role of Rufy3 in more detail. Examining Rufy3-KO neurons, we found that Rufy3 is recruited via glycoprotein M6A to detergent-resistant membrane domains, which are biochemically similar to lipid rafts. We also clarified that Rufy3, as a component of a ternary complex, induces the assembly of Rap2 in the axonal growth cone, whereas in the absence of Rufy3, the accumulation of a Rac guanine nucleotide exchange factor, T-cell lymphoma invasion and metastasis 2 (Tiam2/STEF), is inhibited downstream of Rap2. We also found that Rufy3 regulates the cellular localization of Rap2 and Tiam2/STEF. Taken together, we conclude that Rufy3 is a physiological adapter for Rap2 and activates Tiam2/STEF in glycoprotein M6A-regulated neuronal polarity and axon growth.
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Affiliation(s)
- Atsuko Honda
- From the Department of Neurochemistry and Molecular Cell Biology.,Trans-disciplinary Research Program, and
| | - Hiroshi Usui
- Department of Cellular Neurobiology, Institute for Brain Research, Niigata University, Chuo-ku, Niigata 951-8510, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Institute for Brain Research, Niigata University, Chuo-ku, Niigata 951-8510, Japan
| | - Michihiro Igarashi
- From the Department of Neurochemistry and Molecular Cell Biology, .,Trans-disciplinary Research Program, and
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26
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Xu Z, Gakhar L, Bain FE, Spies M, Fuentes EJ. The Tiam1 guanine nucleotide exchange factor is auto-inhibited by its pleckstrin homology coiled-coil extension domain. J Biol Chem 2017; 292:17777-17793. [PMID: 28882897 PMCID: PMC5663878 DOI: 10.1074/jbc.m117.799114] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 08/25/2017] [Indexed: 12/22/2022] Open
Abstract
T-cell lymphoma invasion and metastasis 1 (Tiam1) is a Dbl-family guanine nucleotide exchange factor (GEF) that specifically activates the Rho-family GTPase Rac1 in response to upstream signals, thereby regulating cellular processes including cell adhesion and migration. Tiam1 contains multiple domains, including an N-terminal pleckstrin homology coiled-coiled extension (PHn-CC-Ex) and catalytic Dbl homology and C-terminal pleckstrin homology (DH-PHc) domain. Previous studies indicate that larger fragments of Tiam1, such as the region encompassing the N-terminal to C-terminal pleckstrin homology domains (PHn-PHc), are auto-inhibited. However, the domains in this region responsible for inhibition remain unknown. Here, we show that the PHn-CC-Ex domain inhibits Tiam1 GEF activity by directly interacting with the catalytic DH-PHc domain, preventing Rac1 binding and activation. Enzyme kinetics experiments suggested that Tiam1 is auto-inhibited through occlusion of the catalytic site rather than by allostery. Small angle X-ray scattering and ensemble modeling yielded models of the PHn-PHc fragment that indicate it is in equilibrium between "open" and "closed" conformational states. Finally, single-molecule experiments support a model in which conformational sampling between the open and closed states of Tiam1 contributes to Rac1 dissociation. Our results highlight the role of the PHn-CC-Ex domain in Tiam1 GEF regulation and suggest a combinatorial model for GEF inhibition and activation of the Rac1 signaling pathway.
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Affiliation(s)
- Zhen Xu
- From the Department of Biochemistry
| | - Lokesh Gakhar
- From the Department of Biochemistry
- Protein Crystallography Facility, and
| | | | - Maria Spies
- From the Department of Biochemistry
- Holden Comprehensive Cancer Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Ernesto J Fuentes
- From the Department of Biochemistry,
- Holden Comprehensive Cancer Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
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27
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Saito A, Cai L, Matsuhisa K, Ohtake Y, Kaneko M, Kanemoto S, Asada R, Imaizumi K. Neuronal activity-dependent local activation of dendritic unfolded protein response promotes expression of brain-derived neurotrophic factor in cell soma. J Neurochem 2017; 144:35-49. [PMID: 28921568 PMCID: PMC5765399 DOI: 10.1111/jnc.14221] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 08/21/2017] [Accepted: 09/08/2017] [Indexed: 12/20/2022]
Abstract
Unfolded protein response (UPR) has roles not only in resolving the accumulation of unfolded proteins owing to endoplasmic reticulum (ER) stress, but also in regulation of cellular physiological functions. ER stress transducers providing the branches of UPR signaling are known to localize in distal dendritic ER of neurons. These reports suggest that local activation of UPR branches may produce integrated outputs for distant communication, and allow regulation of local events in highly polarized neurons. Here, we demonstrated that synaptic activity‐ and brain‐derived neurotrophic factor (BDNF)‐dependent local activation of UPR signaling could be associated with dendritic functions through retrograde signal propagation by using murine neuroblastoma cell line, Neuro‐2A and primary cultured hippocampal neurons derived from postnatal day 0 litter C57BL/6 mice. ER stress transducer, inositol‐requiring kinase 1 (IRE1), was activated at postsynapses in response to excitatory synaptic activation. Activated dendritic IRE1 accelerated accumulation of the downstream transcription factor, x‐box‐binding protein 1 (XBP1), in the nucleus. Interestingly, excitatory synaptic activation‐dependent up‐regulation of XBP1 directly facilitated transcriptional activation of BDNF. BDNF in turn drove its own expression via IRE1‐XBP1 pathway in a protein kinase A‐dependent manner. Exogenous treatment with BDNF promoted extension and branching of dendrites through the protein kinase A‐IRE1‐XBP1 cascade. Taken together, our findings indicate novel mechanisms for communication between soma and distal sites of polarized neurons that are coordinated by local activation of IRE1‐XBP1 signaling. Synaptic activity‐ and BDNF‐dependent distinct activation of dendritic IRE1‐XBP1 cascade drives BDNF expression in cell soma and may be involved in dendritic extension. Cover Image for this issue: doi. 10.1111/jnc.14159. ![]()
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Affiliation(s)
- Atsushi Saito
- Department of Stress Protein Processing, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Longjie Cai
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Koji Matsuhisa
- Department of Stress Protein Processing, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Yosuke Ohtake
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Masayuki Kaneko
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Soshi Kanemoto
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Rie Asada
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Kazunori Imaizumi
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
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28
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Saadipour K, MacLean M, Pirkle S, Ali S, Lopez-Redondo ML, Stokes DL, Chao MV. The transmembrane domain of the p75 neurotrophin receptor stimulates phosphorylation of the TrkB tyrosine kinase receptor. J Biol Chem 2017; 292:16594-16604. [PMID: 28821608 PMCID: PMC5633122 DOI: 10.1074/jbc.m117.788729] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 07/31/2017] [Indexed: 01/19/2023] Open
Abstract
The function of protein products generated from intramembraneous cleavage by the γ-secretase complex is not well defined. The γ-secretase complex is responsible for the cleavage of several transmembrane proteins, most notably the amyloid precursor protein that results in Aβ, a transmembrane (TM) peptide. Another protein that undergoes very similar γ-secretase cleavage is the p75 neurotrophin receptor. However, the fate of the cleaved p75 TM domain is unknown. p75 neurotrophin receptor is highly expressed during early neuronal development and regulates survival and process formation of neurons. Here, we report that the p75 TM can stimulate the phosphorylation of TrkB (tyrosine kinase receptor B). In vitro phosphorylation experiments indicated that a peptide representing p75 TM increases TrkB phosphorylation in a dose- and time-dependent manner. Moreover, mutagenesis analyses revealed that a valine residue at position 264 in the rat p75 neurotrophin receptor is necessary for the ability of p75 TM to induce TrkB phosphorylation. Because this residue is just before the γ-secretase cleavage site, we then investigated whether the p75(αγ) peptide, which is a product of both α- and γ-cleavage events, could also induce TrkB phosphorylation. Experiments using TM domains from other receptors, EGFR and FGFR1, failed to stimulate TrkB phosphorylation. Co-immunoprecipitation and biochemical fractionation data suggested that p75 TM stimulates TrkB phosphorylation at the cell membrane. Altogether, our results suggest that TrkB activation by p75(αγ) peptide may be enhanced in situations where the levels of the p75 receptor are increased, such as during brain injury, Alzheimer's disease, and epilepsy.
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Affiliation(s)
- Khalil Saadipour
- From the Departments of Cell Biology, Physiology & Neuroscience, and Psychiatry, Skirball Institute of Biomolecular Medicine, New York University Langone Medical Center, New York, New York 10016
| | - Michael MacLean
- From the Departments of Cell Biology, Physiology & Neuroscience, and Psychiatry, Skirball Institute of Biomolecular Medicine, New York University Langone Medical Center, New York, New York 10016
| | - Sean Pirkle
- From the Departments of Cell Biology, Physiology & Neuroscience, and Psychiatry, Skirball Institute of Biomolecular Medicine, New York University Langone Medical Center, New York, New York 10016
| | - Solav Ali
- From the Departments of Cell Biology, Physiology & Neuroscience, and Psychiatry, Skirball Institute of Biomolecular Medicine, New York University Langone Medical Center, New York, New York 10016
| | - Maria-Luisa Lopez-Redondo
- From the Departments of Cell Biology, Physiology & Neuroscience, and Psychiatry, Skirball Institute of Biomolecular Medicine, New York University Langone Medical Center, New York, New York 10016
| | - David L Stokes
- From the Departments of Cell Biology, Physiology & Neuroscience, and Psychiatry, Skirball Institute of Biomolecular Medicine, New York University Langone Medical Center, New York, New York 10016
| | - Moses V Chao
- From the Departments of Cell Biology, Physiology & Neuroscience, and Psychiatry, Skirball Institute of Biomolecular Medicine, New York University Langone Medical Center, New York, New York 10016
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29
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Saito A, Cai L, Matsuhisa K, Ohtake Y, Kaneko M, Kanemoto S, Asada R, Imaizumi K. Neuronal activity-dependent local activation of dendritic unfolded protein response promotes expression of brain-derived neurotrophic factor in cell soma. J Neurochem 2017. [PMID: 28921568 DOI: 10.1111/jnc.14159] [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: 12/01/2022]
Abstract
Unfolded protein response (UPR) has roles not only in resolving the accumulation of unfolded proteins owing to endoplasmic reticulum (ER) stress, but also in regulation of cellular physiological functions. ER stress transducers providing the branches of UPR signaling are known to localize in distal dendritic ER of neurons. These reports suggest that local activation of UPR branches may produce integrated outputs for distant communication, and allow regulation of local events in highly polarized neurons. Here, we demonstrated that synaptic activity- and brain-derived neurotrophic factor (BDNF)-dependent local activation of UPR signaling could be associated with dendritic functions through retrograde signal propagation by using murine neuroblastoma cell line, Neuro-2A and primary cultured hippocampal neurons derived from postnatal day 0 litter C57BL/6 mice. ER stress transducer, inositol-requiring kinase 1 (IRE1), was activated at postsynapses in response to excitatory synaptic activation. Activated dendritic IRE1 accelerated accumulation of the downstream transcription factor, x-box-binding protein 1 (XBP1), in the nucleus. Interestingly, excitatory synaptic activation-dependent up-regulation of XBP1 directly facilitated transcriptional activation of BDNF. BDNF in turn drove its own expression via IRE1-XBP1 pathway in a protein kinase A-dependent manner. Exogenous treatment with BDNF promoted extension and branching of dendrites through the protein kinase A-IRE1-XBP1 cascade. Taken together, our findings indicate novel mechanisms for communication between soma and distal sites of polarized neurons that are coordinated by local activation of IRE1-XBP1 signaling. Synaptic activity- and BDNF-dependent distinct activation of dendritic IRE1-XBP1 cascade drives BDNF expression in cell soma and may be involved in dendritic extension. Cover Image for this issue: doi. 10.1111/jnc.14159.
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Affiliation(s)
- Atsushi Saito
- Department of Stress Protein Processing, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Longjie Cai
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Koji Matsuhisa
- Department of Stress Protein Processing, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Yosuke Ohtake
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Masayuki Kaneko
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Soshi Kanemoto
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Rie Asada
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
| | - Kazunori Imaizumi
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
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30
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Tajbakhsh A, Mokhtari-Zaer A, Rezaee M, Afzaljavan F, Rivandi M, Hassanian SM, Ferns GA, Pasdar A, Avan A. Therapeutic Potentials of BDNF/TrkB in Breast Cancer; Current Status and Perspectives. J Cell Biochem 2017; 118:2502-2515. [PMID: 28230291 DOI: 10.1002/jcb.25943] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 02/21/2017] [Indexed: 12/14/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is a potent neurotrophic factor that has been shown to stimulate breast cancer cell growth and metastasis via tyrosine kinase receptors TrkA, TrkB, and the p75NTR death receptor. The aberrant activation of BDNF/TrkB pathways can modulate several signaling pathways, including Akt/PI3K, Jak/STAT, NF-kB, UPAR/UPA, Wnt/β-catenin, and VEGF pathways as well as the ER receptor. Several microRNAs have been identified that are involved in the modulation of BDNF/TrkB pathways. These include miR-206, miR-204, MiR-200a/c, MiR-210, MiR-134, and MiR-191; and these may be of value as prognostic and predictive biomarkers for detecting patients at high risk of developing breast cancer. It has been also been demonstrated that a high expression of genes involved in the BDNF pathway in breast cancer is associated with poor clinical outcome and reduced survival of patients. Several approaches have been developed for targeting this pathway, for example TKr inhibitors (AZD6918, CEP-701) and RNA interference. The aim of the current review was to provide an overview of the role of BDNF/TrkB pathways in the pathogenesis of breast cancer and its value as a potential therapeutic target. J. Cell. Biochem. 118: 2502-2515, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Amir Tajbakhsh
- Department of Modern Sciences and Technologies, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amin Mokhtari-Zaer
- Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Neurogenic Inflammation Research Centre and Department of Physiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mehdi Rezaee
- Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Medical Biotechnology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Fahimeh Afzaljavan
- Department of Modern Sciences and Technologies, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mehdi Rivandi
- Department of Modern Sciences and Technologies, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Seyed Mahdi Hassanian
- Department of Medical Biochemistry, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Metabolic Syndrome Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Gordon A Ferns
- Brighton & Sussex Medical School, Division of Medical Education, Falmer, Brighton, UK
| | - Alireza Pasdar
- Department of Modern Sciences and Technologies, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Division of Applied Medicine, Medical School, University of Aberdeen, Foresterhill, Aberdeen, UK.,Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amir Avan
- Metabolic Syndrome Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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31
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Hedrick NG, Harward SC, Hall CE, Murakoshi H, McNamara JO, Yasuda R. Rho GTPase complementation underlies BDNF-dependent homo- and heterosynaptic plasticity. Nature 2016; 538:104-108. [PMID: 27680697 DOI: 10.1038/nature19784] [Citation(s) in RCA: 156] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 08/22/2016] [Indexed: 01/01/2023]
Abstract
The Rho GTPase proteins Rac1, RhoA and Cdc42 have a central role in regulating the actin cytoskeleton in dendritic spines, thereby exerting control over the structural and functional plasticity of spines and, ultimately, learning and memory. Although previous work has shown that precise spatiotemporal coordination of these GTPases is crucial for some forms of cell morphogenesis, the nature of such coordination during structural spine plasticity is unclear. Here we describe a three-molecule model of structural long-term potentiation (sLTP) of murine dendritic spines, implicating the localized, coincident activation of Rac1, RhoA and Cdc42 as a causal signal of sLTP. This model posits that complete tripartite signal overlap in spines confers sLTP, but that partial overlap primes spines for structural plasticity. By monitoring the spatiotemporal activation patterns of these GTPases during sLTP, we find that such spatiotemporal signal complementation simultaneously explains three integral features of plasticity: the facilitation of plasticity by brain-derived neurotrophic factor (BDNF), the postsynaptic source of which activates Cdc42 and Rac1, but not RhoA; heterosynaptic facilitation of sLTP, which is conveyed by diffusive Rac1 and RhoA activity; and input specificity, which is afforded by spine-restricted Cdc42 activity. Thus, we present a form of biochemical computation in dendrites involving the controlled complementation of three molecules that simultaneously ensures signal specificity and primes the system for plasticity.
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Affiliation(s)
- Nathan G Hedrick
- Neurobiology Department, Duke University Medical Center, Research Drive, Durham, North Carolina 27710, USA
| | - Stephen C Harward
- Neurobiology Department, Duke University Medical Center, Research Drive, Durham, North Carolina 27710, USA
| | - Charles E Hall
- Neurobiology Department, Duke University Medical Center, Research Drive, Durham, North Carolina 27710, USA
| | - Hideji Murakoshi
- National Institute for Physiological Science, Myodaiji, Okazaki, Aichi, 444-8585, Japan
| | - James O McNamara
- Neurobiology Department, Duke University Medical Center, Research Drive, Durham, North Carolina 27710, USA
| | - Ryohei Yasuda
- Neurobiology Department, Duke University Medical Center, Research Drive, Durham, North Carolina 27710, USA.,Max Planck Florida Institute for Neuroscience, 1 Max Planck Way, Jupiter, Florida 33458, USA
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32
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Gonzalez A, Moya-Alvarado G, Gonzalez-Billaut C, Bronfman FC. Cellular and molecular mechanisms regulating neuronal growth by brain-derived neurotrophic factor. Cytoskeleton (Hoboken) 2016; 73:612-628. [PMID: 27223597 DOI: 10.1002/cm.21312] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/20/2016] [Accepted: 05/23/2016] [Indexed: 12/31/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) and its receptors TrkB and p75 regulate dendritic and axonal growth during development and maintenance of the mature nervous system; however, the cellular and molecular mechanisms underlying this process are not fully understood. In recent years, several advances have shed new light on the processes behind the regulation of BDNF-mediated structural plasticity including control of neuronal transcription, local translation of proteins, and regulation of cytoskeleton and membrane dynamics. In this review, we summarize recent advances in the field of BDNF signaling in neurons to induce neuronal growth. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Andres Gonzalez
- MINREB and Center for Ageing and Regeneration (CARE UC), Faculty of Biological Sciences, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Guillermo Moya-Alvarado
- MINREB and Center for Ageing and Regeneration (CARE UC), Faculty of Biological Sciences, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Christian Gonzalez-Billaut
- Laboratory of Cell and Neuronal Dynamics, Department of Biology, Faculty of Sciences, Universidad de Chile and Geroscience Center for Brain Health and Metabolism, Santiago, Chile
| | - Francisca C Bronfman
- MINREB and Center for Ageing and Regeneration (CARE UC), Faculty of Biological Sciences, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile.
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33
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Kalirin is required for BDNF-TrkB stimulated neurite outgrowth and branching. Neuropharmacology 2016; 107:227-238. [PMID: 27036892 DOI: 10.1016/j.neuropharm.2016.03.050] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 03/03/2016] [Accepted: 03/28/2016] [Indexed: 01/19/2023]
Abstract
Exogenous brain-derived neurotrophic factor (BDNF), acting through TrkB, is known to promote neurite formation and branching. This response to BDNF was eliminated by inhibition of TrkB kinase and by specific inhibition of the GEF1 domain of Kalirin, which activates Rac1. Neurons from Kalrn knockout mice were unable to activate Rac1 in response to BDNF. BDNF-triggered neurite outgrowth was abolished when Kalrn expression was reduced using shRNA that targets all of the major Kalrn isoforms, and reduced in neurons from Kalrn knockout mice. The Kalrn isoforms expressed early in development also include a GEF2 domain that activates RhoA. However, BDNF-stimulated neurite outgrowth in Kalrn knockout neurons was rescued by expression of Kalirin-7, which includes only the GEF1 domain but lacks the GEF2 domain. Dendritic morphogenesis, which requires spatially restricted, coordinated changes in the actin cytoskeleton and in the organization of microtubules, involves essential contributions from multiple Rho GEFs. Since Tiam1, another Rho GEF, is also required for BDNF-stimulated neurite outgrowth, an inhibitory fragment of Tiam1 (PHn-CC-EX) was tested and found to interfere with both Kalirin and Tiam1 GEF activity. The prolonged TrkB activation observed in response to BDNF in Kalrn knockout neurons and the altered time course and extent of ERK, CREB and Akt activation observed in the absence of Kalrn would be expected to alter the response of these neurons to other regulatory factors.
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Matsuzawa K, Akita H, Watanabe T, Kakeno M, Matsui T, Wang S, Kaibuchi K. PAR3-aPKC regulates Tiam1 by modulating suppressive internal interactions. Mol Biol Cell 2016; 27:1511-23. [PMID: 26941335 PMCID: PMC4850038 DOI: 10.1091/mbc.e15-09-0670] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 02/24/2016] [Indexed: 01/19/2023] Open
Abstract
The Rac1 activator Tiam1 is inhibited by internal interactions. Phosphorylation of Tiam1 by aPKC lends bias to an “open” conformation, potentiating its activation and allowing for its localization through protein–protein interactions. Tiam1 is one of the most extensively analyzed activators of the small GTPase Rac. However, fundamental aspects of its regulation are poorly understood. Here we demonstrate that Tiam1 is functionally suppressed by internal interactions and that the PAR complex participates in its full activation. The N-terminal region of Tiam1 binds to the protein-binding and catalytic domains to inhibit its localization and activation. Atypical PKCs phosphorylate Tiam1 to relieve its intramolecular interactions, and the subsequent stabilization of its interaction with PAR3 allows it to exert localized activity. By analyzing Tiam1 regulation by PAR3-aPKC within the context of PDGF signaling, we also show that PAR3 directly binds PDGF receptor β. Thus we provide the first evidence for the negative regulation of Tiam1 by internal interactions, elucidate the nature of Tiam1 regulation by the PAR complex, and reveal a novel role for the PAR complex in PDGF signaling.
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Affiliation(s)
- Kenji Matsuzawa
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Hiroki Akita
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Takashi Watanabe
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Mai Kakeno
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Toshinori Matsui
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Shujie Wang
- Department of Neural Regeneration and Cell Communication, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan
| | - Kozo Kaibuchi
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
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Vacca M, Tripathi KP, Speranza L, Aiese Cigliano R, Scalabrì F, Marracino F, Madonna M, Sanseverino W, Perrone-Capano C, Guarracino MR, D'Esposito M. Effects of Mecp2 loss of function in embryonic cortical neurons: a bioinformatics strategy to sort out non-neuronal cells variability from transcriptome profiling. BMC Bioinformatics 2016; 17 Suppl 2:14. [PMID: 26821710 PMCID: PMC4959389 DOI: 10.1186/s12859-015-0859-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Background Mecp2 null mice model Rett syndrome (RTT) a human neurological disorder affecting females after apparent normal pre- and peri-natal developmental periods. Neuroanatomical studies in cerebral cortex of RTT mouse models revealed delayed maturation of neuronal morphology and autonomous as well as non-cell autonomous reduction in dendritic complexity of postnatal cortical neurons. However, both morphometric parameters and high-resolution expression profile of cortical neurons at embryonic developmental stage have not yet been studied. Here we address these topics by using embryonic neuronal primary cultures from Mecp2 loss of function mouse model. Results We show that embryonic primary cortical neurons of Mecp2 null mice display reduced neurite complexity possibly reflecting transcriptional changes. We used RNA-sequencing coupled with a bioinformatics comparative approach to identify and remove the contribution of variable and hard to quantify non-neuronal brain cells present in our in vitro cell cultures. Conclusions Our results support the need to investigate both Mecp2 morphological as well as molecular effect in neurons since prenatal developmental stage, long time before onset of Rett symptoms. Electronic supplementary material The online version of this article (doi:10.1186/s12859-015-0859-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marcella Vacca
- Institute of Genetics and Biophysics "A. Buzzati Traverso", National Research Council (CNR)-80131, Naples, Italy.
| | - Kumar Parijat Tripathi
- Laboratory for Genomics, Transcriptomics and Proteomics (LAB-GTP), High Performance Computing and Networking Institute (ICAR), National Research Council (CNR)-80131, Naples, Italy.
| | - Luisa Speranza
- Institute of Genetics and Biophysics "A. Buzzati Traverso", National Research Council (CNR)-80131, Naples, Italy.
| | | | | | | | | | - Walter Sanseverino
- Sequentia Biotech SL, Calle Comte D'Urgell, 240 08036, Barcelona, Spain.
| | - Carla Perrone-Capano
- Institute of Genetics and Biophysics "A. Buzzati Traverso", National Research Council (CNR)-80131, Naples, Italy. .,Department of Pharmacy, University of Naples Federico II, Naples, Italy.
| | - Mario Rosario Guarracino
- Laboratory for Genomics, Transcriptomics and Proteomics (LAB-GTP), High Performance Computing and Networking Institute (ICAR), National Research Council (CNR)-80131, Naples, Italy.
| | - Maurizio D'Esposito
- Institute of Genetics and Biophysics "A. Buzzati Traverso", National Research Council (CNR)-80131, Naples, Italy. .,IRCCS Neuromed, via dell'Elettronica, Pozzilli (Is), Italy.
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Choi SY, Han K. Emerging role of synaptic actin-regulatory pathway in the pathophysiology of mood disorders. Anim Cells Syst (Seoul) 2015. [DOI: 10.1080/19768354.2015.1086435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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Abstract
Neurons are highly polarized cells with structurally and functionally distinct processes called axons and dendrites. This polarization underlies the directional flow of information in the central nervous system, so the establishment and maintenance of neuronal polarization is crucial for correct development and function. Great progress in our understanding of how neurons establish their polarity has been made through the use of cultured hippocampal neurons, while recent technological advances have enabled in vivo analysis of axon specification and elongation. This short review and accompanying poster highlight recent advances in this fascinating field, with an emphasis on the signaling mechanisms underlying axon and dendrite specification in vitro and in vivo.
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Affiliation(s)
- Tetsuya Takano
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Chundi Xu
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Yasuhiro Funahashi
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Takashi Namba
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Kozo Kaibuchi
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
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Whalley HJ, Porter AP, Diamantopoulou Z, White GRM, Castañeda-Saucedo E, Malliri A. Cdk1 phosphorylates the Rac activator Tiam1 to activate centrosomal Pak and promote mitotic spindle formation. Nat Commun 2015; 6:7437. [PMID: 26078008 PMCID: PMC4490568 DOI: 10.1038/ncomms8437] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 05/08/2015] [Indexed: 01/13/2023] Open
Abstract
Centrosome separation is critical for bipolar spindle formation and the accurate segregation of chromosomes during mammalian cell mitosis. Kinesin-5 (Eg5) is a microtubule motor essential for centrosome separation, and Tiam1 and its substrate Rac antagonize Eg5-dependent centrosome separation in early mitosis promoting efficient chromosome congression. Here we identify S1466 of Tiam1 as a novel Cdk1 site whose phosphorylation is required for the mitotic function of Tiam1. We find that this phosphorylation of Tiam1 is required for the activation of group I p21-activated kinases (Paks) on centrosomes in prophase. Further, we show that both Pak1 and Pak2 counteract centrosome separation in a kinase-dependent manner and demonstrate that they act downstream of Tiam1. We also show that depletion of Pak1/2 allows cells to escape monopolar arrest by Eg5 inhibition, highlighting the potential importance of this signalling pathway for the development of Eg5 inhibitors as cancer therapeutics.
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Affiliation(s)
- Helen J. Whalley
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester M20 4BX, UK
| | - Andrew P. Porter
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester M20 4BX, UK
| | - Zoi Diamantopoulou
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester M20 4BX, UK
| | - Gavin R. M. White
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester M20 4BX, UK
| | - Eduardo Castañeda-Saucedo
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester M20 4BX, UK
| | - Angeliki Malliri
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester M20 4BX, UK
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Torii T, Ohno N, Miyamoto Y, Kawahara K, Saitoh Y, Nakamura K, Takashima S, Sakagami H, Tanoue A, Yamauchi J. Arf6 guanine-nucleotide exchange factor cytohesin-2 regulates myelination in nerves. Biochem Biophys Res Commun 2015; 460:819-25. [PMID: 25824033 DOI: 10.1016/j.bbrc.2015.03.113] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 03/22/2015] [Indexed: 11/16/2022]
Abstract
In postnatal development of the peripheral nervous system (PNS), Schwann cells differentiate to insulate neuronal axons with myelin sheaths, increasing the nerve conduction velocity. To produce the mature myelin sheath with its multiple layers, Schwann cells undergo dynamic morphological changes. While extracellular molecules such as growth factors and cell adhesion ligands are known to regulate the myelination process, the intracellular molecular mechanism underlying myelination remains unclear. In this study, we have produced Schwann cell-specific conditional knockout mice for cytohesin-2, a guanine-nucleotide exchange factor (GEF) specifically activating Arf6. Arf6, a member of the Ras-like protein family, participates in various cellular functions including cell morphological changes. Cytohesin-2 knockout mice exhibit decreased Arf6 activity and reduced myelin thickness in the sciatic nerves, with decreased expression levels of myelin protein zero (MPZ), the major myelin marker protein. These results are consistent with those of experiments in which Schwann cell-neuronal cultures were treated with pan-cytohesin inhibitor SecinH3. On the other hand, the numbers of Ki67-positive cells in knockout mice and controls are comparable, indicating that cytohesin-2 does not have a positive effect on cell numbers. Thus, signaling through cytohesin-2 is required for myelination by Schwann cells, and cytohesin-2 is added to the list of molecules known to underlie PNS myelination.
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Affiliation(s)
- Tomohiro Torii
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nobuhiko Ohno
- Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan; School of Life Science, The Graduate University for Advanced Studies and The National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
| | - Yuki Miyamoto
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
| | - Kazuko Kawahara
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
| | - Yurika Saitoh
- Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan
| | - Kazuaki Nakamura
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
| | - Shou Takashima
- Glycobiology Research Unit, The Noguchi Institute, Itabashi, Tokyo 173-0003, Japan
| | - Hiroyuki Sakagami
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa 252-0374, Japan
| | - Akito Tanoue
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
| | - Junji Yamauchi
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan; Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo 113-8510, Japan.
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40
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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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41
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Um K, Niu S, Duman JG, Cheng JX, Tu YK, Schwechter B, Liu F, Hiles L, Narayanan AS, Ash RT, Mulherkar S, Alpadi K, Smirnakis SM, Tolias KF. Dynamic control of excitatory synapse development by a Rac1 GEF/GAP regulatory complex. Dev Cell 2014; 29:701-15. [PMID: 24960694 DOI: 10.1016/j.devcel.2014.05.011] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 04/23/2014] [Accepted: 05/14/2014] [Indexed: 11/18/2022]
Abstract
The small GTPase Rac1 orchestrates actin-dependent remodeling essential for numerous cellular processes including synapse development. While precise spatiotemporal regulation of Rac1 is necessary for its function, little is known about the mechanisms that enable Rac1 activators (GEFs) and inhibitors (GAPs) to act in concert to regulate Rac1 signaling. Here, we identify a regulatory complex composed of a Rac-GEF (Tiam1) and a Rac-GAP (Bcr) that cooperate to control excitatory synapse development. Disruption of Bcr function within this complex increases Rac1 activity and dendritic spine remodeling, resulting in excessive synaptic growth that is rescued by Tiam1 inhibition. Notably, EphB receptors utilize the Tiam1-Bcr complex to control synaptogenesis. Following EphB activation, Tiam1 induces Rac1-dependent spine formation, whereas Bcr prevents Rac1-mediated receptor internalization, promoting spine growth over retraction. The finding that a Rac-specific GEF/GAP complex is required to maintain optimal levels of Rac1 signaling provides an important insight into the regulation of small GTPases.
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Affiliation(s)
- Kyongmi Um
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Sanyong Niu
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Joseph G Duman
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Jinxuan X Cheng
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Yen-Kuei Tu
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Program, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Brandon Schwechter
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Feng Liu
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Laura Hiles
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Anjana S Narayanan
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Ryan T Ash
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Kannan Alpadi
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Stelios M Smirnakis
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Kimberley F Tolias
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Program, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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Zhang Y, Hu H, Tian T, Zhang L, Zhao D, Wu Q, Chang Y, Wang Q, Zhou S, Feng G, Huang F. Mst3b promotes spinal cord neuronal regeneration by promoting growth cone branching out in spinal cord injury rats. Mol Neurobiol 2014; 51:1144-57. [PMID: 24990316 DOI: 10.1007/s12035-014-8785-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 06/09/2014] [Indexed: 01/05/2023]
Abstract
Spinal cord injury is a severe clinical problem, and research searching activity molecular that can promote spinal cord injury repairing is very prevalent. Mst3b can promote repair of damaged peripheral nerves and the optic nerve, but has been rarely reported in spinal cord injury research. Through detecting its expression in different periods of injured spinal cord, we found that the expression of Mst3b was significantly upregulated in injured spinal cord neurons. Increasing Mst3b expression using adenovirus in vivo and in vitro promoted axonal regeneration of spinal cord neurons, which led to behavioral and electrophysiological improvement. Downregulation of Mst3b level had the adverse effects. Increasing Mst3b expression in PC12 cells resulted in an elevation of P42/44(MAPK) and LIMK/Cofilin activation. These results identified Mst3b as a powerful regulator for promoting spinal cord injury recovery through the P42/44(MAPK) and LIMK/Cofilin signaling pathways.
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Affiliation(s)
- Yuqiang Zhang
- Institute of Human Anatomy and Histology and Embryology, Otology & Neuroscience Center, Binzhou Medical University, 346 Guanhai Road, Laishan, Shandong Province, 264003, China
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De Filippis B, Romano E, Laviola G. Aberrant Rho GTPases signaling and cognitive dysfunction: in vivo evidence for a compelling molecular relationship. Neurosci Biobehav Rev 2014; 46 Pt 2:285-301. [PMID: 24971827 DOI: 10.1016/j.neubiorev.2014.06.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 05/30/2014] [Accepted: 06/17/2014] [Indexed: 01/11/2023]
Abstract
Rho GTPases are key intracellular signaling molecules that coordinate dynamic changes in the actin cytoskeleton, thereby stimulating a variety of processes, including morphogenesis, migration, neuronal development, cell division and adhesion. Deviations from normal Rho GTPases activation state have been proposed to disrupt cognition and synaptic plasticity. This review focuses on the functional consequences of genetic ablation of upstream and downstream Rho GTPases molecules on cognitive function and neuronal morphology and connectivity. Available information on this issue is described and compared to that gained from mice carrying mutations in the most studied Rho GTPases and from pharmacological in vivo studies in which brain Rho GTPases signaling was modulated. Results from reviewed literature provide definitive evidence of a compelling link between Rho GTPases signaling and cognitive function, thus supporting the notion that Rho GTPases and their downstream effectors may represent important therapeutic targets for disorders associated with cognitive dysfunction.
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Affiliation(s)
- Bianca De Filippis
- Sect. Behavioural Neuroscience, Department of Cell Biology & Neuroscience, Istituto Superiore di Sanità, Roma, Italy.
| | - Emilia Romano
- Sect. Behavioural Neuroscience, Department of Cell Biology & Neuroscience, Istituto Superiore di Sanità, Roma, Italy; Bambino Gesù, Children Hospital, IRCCS, Roma, Italy
| | - Giovanni Laviola
- Sect. Behavioural Neuroscience, Department of Cell Biology & Neuroscience, Istituto Superiore di Sanità, Roma, Italy
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Sala C, Segal M. Dendritic spines: the locus of structural and functional plasticity. Physiol Rev 2014; 94:141-88. [PMID: 24382885 DOI: 10.1152/physrev.00012.2013] [Citation(s) in RCA: 336] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The introduction of high-resolution time lapse imaging and molecular biological tools has changed dramatically the rate of progress towards the understanding of the complex structure-function relations in synapses of central spiny neurons. Standing issues, including the sequence of molecular and structural processes leading to formation, morphological change, and longevity of dendritic spines, as well as the functions of dendritic spines in neurological/psychiatric diseases are being addressed in a growing number of recent studies. There are still unsettled issues with respect to spine formation and plasticity: Are spines formed first, followed by synapse formation, or are synapses formed first, followed by emergence of a spine? What are the immediate and long-lasting changes in spine properties following exposure to plasticity-producing stimulation? Is spine volume/shape indicative of its function? These and other issues are addressed in this review, which highlights the complexity of molecular pathways involved in regulation of spine structure and function, and which contributes to the understanding of central synaptic interactions in health and disease.
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Turnley AM, Basrai HS, Christie KJ. Is integration and survival of newborn neurons the bottleneck for effective neural repair by endogenous neural precursor cells? Front Neurosci 2014; 8:29. [PMID: 24600341 PMCID: PMC3929902 DOI: 10.3389/fnins.2014.00029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Accepted: 02/01/2014] [Indexed: 01/28/2023] Open
Abstract
After two decades of research the existence of adult neural precursor cells and the phenomenon of adult neurogenesis is well established. However, there has been little or no effective harnessing of these endogenous cells to promote functional neuronal replacement following neural injury or disease. Neural precursor cells can respond to neural damage by proliferating, migrating to the site of injury, and differentiating into neuronal or glial lineages. However, after a month or so, very few or no newborn neurons can be detected, suggesting that even though neuroblasts are generated, they generally fail to survive as mature neurons and contribute to the local circuitry. Is this lack of survival and integration one of the major bottlenecks that inhibits effective neuronal replacement and subsequent repair of the nervous system following injury or disease? In this perspective article the possibility that this bottleneck can be targeted to enhance the integration and subsequent survival of newborn neurons will be explored and will suggest some possible mechanisms that may need to be modulated for this to occur.
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Affiliation(s)
- Ann M Turnley
- Department of Anatomy and Neuroscience, The University of Melbourne Parkville, VIC, Australia
| | - Harleen S Basrai
- Department of Anatomy and Neuroscience, The University of Melbourne Parkville, VIC, Australia
| | - Kimberly J Christie
- Department of Anatomy and Neuroscience, The University of Melbourne Parkville, VIC, Australia
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Hottman DA, Li L. Protein prenylation and synaptic plasticity: implications for Alzheimer's disease. Mol Neurobiol 2014; 50:177-85. [PMID: 24390573 DOI: 10.1007/s12035-013-8627-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 12/20/2013] [Indexed: 12/11/2022]
Abstract
Protein prenylation is an important lipid posttranslational modification of proteins. It includes protein farnesylation and geranylgeranylation, in which the 15-carbon farnesyl pyrophosphate or 20-carbon geranylgeranyl pyrophosphate is attached to the C-terminus of target proteins, catalyzed by farnesyl transferase or geranylgeranyl transferases, respectively. Protein prenylation facilitates the anchoring of proteins into the cell membrane and mediates protein-protein interactions. Among numerous proteins that undergo prenylation, small GTPases represent the largest group of prenylated proteins. Small GTPases are involved in regulating a plethora of cellular functions including synaptic plasticity. The prenylation status of small GTPases determines the subcellular locations and functions of the proteins. Dysregulation or dysfunction of small GTPases leads to the development of different types of disorders. Emerging evidence indicates that prenylated proteins, in particular small GTPases, may play important roles in the pathogenesis of Alzheimer's disease. This review focuses on the prenylation of Ras and Rho subfamilies of small GTPases and its relation to synaptic plasticity and Alzheimer's disease.
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Affiliation(s)
- David A Hottman
- Department of Experimental and Clinical Pharmacology, University of Minnesota, 2001 6th St SE, MTRF 4-208, Minneapolis, MN, 55455, USA
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47
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Form follows function: BDNF and its involvement in sculpting the function and structure of synapses. Neuropharmacology 2014; 76 Pt C:628-38. [DOI: 10.1016/j.neuropharm.2013.05.029] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 05/13/2013] [Accepted: 05/15/2013] [Indexed: 12/31/2022]
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Lai KO, Ip NY. Structural plasticity of dendritic spines: the underlying mechanisms and its dysregulation in brain disorders. Biochim Biophys Acta Mol Basis Dis 2013; 1832:2257-63. [PMID: 24012719 DOI: 10.1016/j.bbadis.2013.08.012] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 08/13/2013] [Accepted: 08/28/2013] [Indexed: 12/17/2022]
Abstract
Dendritic spines are specialized structures on neuronal processes where the majority of excitatory synapses are localized. Spines are highly dynamic, and their stabilization and morphology are influenced by synaptic activity. This extrinsic regulation of spine morphogenesis underlies experience-dependent brain development and information storage within the brain circuitry. In this review, we summarize recent findings that demonstrate the phenomenon of activity-dependent structural plasticity and the molecular mechanisms by which synaptic activity sculpt neuronal connections. Impaired structural plasticity is associated with perturbed brain function in neurodevelopmental disorders such as autism. Information from the mechanistic studies therefore provides important insights into the design of therapeutic strategies for these brain disorders.
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Affiliation(s)
- Kwok-On Lai
- Division of Life Science, Molecular Neuroscience Center and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong
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Lain AR, Creighton CJ, Conneely OM. Research resource: progesterone receptor targetome underlying mammary gland branching morphogenesis. Mol Endocrinol 2013; 27:1743-61. [PMID: 23979845 DOI: 10.1210/me.2013-1144] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Progesterone (P4)-activated progesterone receptors (PRs) play an essential role in driving pregnancy-associated mammary ductal side-branching morphogenesis and alveologenesis. However, the global cistromic and transcriptome responses that are required to elicit P4-dependent branching morphogenesis have not been elucidated. By combining chromatin immunoprecipitation followed by deep sequencing to identify genome-wide PR-binding sites in PR-positive luminal epithelial cells with global gene expression signatures acutely regulated by PRs in the mammary gland, we have identified a mammary epithelial PR targetome associated with active P4-dependent branching morphogenesis in vivo. We demonstrate that P4-induced side-branching is initiated by epithelial cell rearrangement into a multilayered epithelium that sprouts laterally from quiescent ducts via a mechanism requiring P4-dependent activation of Rac-GTPase signaling. We identify effectors of Rac-GTPases as direct transcriptional targets of PRs, and we demonstrate that disruption of the P4-activated Rac-GTPase signaling axis is sufficient to eliminate P4-dependent side-branching. Our data reveal that the molecular mediators of P4-dependent ductal side-branching overlap with those implicated in breast cancer.
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Affiliation(s)
- Ashlee R Lain
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030.
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Vadodaria KC, Jessberger S. Maturation and integration of adult born hippocampal neurons: signal convergence onto small Rho GTPases. Front Synaptic Neurosci 2013; 5:4. [PMID: 23986696 PMCID: PMC3752586 DOI: 10.3389/fnsyn.2013.00004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 07/29/2013] [Indexed: 01/28/2023] Open
Abstract
Adult neurogenesis, restricted to specific regions in the mammalian brain, represents one of the most interesting forms of plasticity in the mature nervous system. Adult-born hippocampal neurons play important roles in certain forms of learning and memory, and altered hippocampal neurogenesis has been associated with a number of neuropsychiatric diseases such as major depression and epilepsy. Newborn neurons go through distinct developmental steps, from a dividing neurogenic precursor to a synaptically integrated mature neuron. Previous studies have uncovered several molecular signaling pathways involved in distinct steps of this maturational process. In this context, the small Rho GTPases, Cdc42, Rac1, and RhoA have recently been shown to regulate the morphological and synaptic maturation of adult-born dentate granule cells in vivo. Distinct upstream regulators, including growth factors that modulate maturation and integration of newborn neurons have been shown to also recruit the small Rho GTPases. Here we review recent findings and highlight the possibility that small Rho GTPases may act as central assimilators, downstream of critical input onto adult-born hippocampal neurons contributing to their maturation and integration into the existing dentate gyrus (DG) circuitry.
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Affiliation(s)
- Krishna C Vadodaria
- Brain Research Institute, University of Zurich Zurich, Switzerland ; Neuroscience Center Zurich, University of Zurich and ETH Zurich Zurich, Switzerland
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