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Singh NK, Gandu SR, Li L, Ni L, Acioglu C, Mirabelli E, Hiester LL, Elkabes S, Firestein BL. Cypin Inhibition as a Therapeutic Approach to Treat Spinal Cord Injury-Induced Mechanical Pain. eNeuro 2024; 11:ENEURO.0451-23.2024. [PMID: 38302457 PMCID: PMC10875717 DOI: 10.1523/eneuro.0451-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/24/2023] [Accepted: 01/04/2024] [Indexed: 02/03/2024] Open
Abstract
Cypin (cytosolic postsynaptic density protein 95 interactor) is the primary guanine deaminase in the central nervous system (CNS), promoting the metabolism of guanine to xanthine, an important reaction in the purine salvage pathway. Activation of the purine salvage pathway leads to the production of uric acid (UA). UA has paradoxical effects, specifically in the context of CNS injury as it confers neuroprotection, but it also promotes pain. Since neuropathic pain is a comorbidity associated with spinal cord injury (SCI), we postulated that small molecule cypin inhibitor B9 treatment could attenuate SCI-induced neuropathic pain, potentially by interfering with UA production. However, we also considered that this treatment could hinder the neuroprotective effects of UA and, in doing so, exacerbate SCI outcomes. To address our hypothesis, we induced a moderate midthoracic contusion SCI in female mice and assessed whether transient intrathecal administration of B9, starting at 1 d postinjury (dpi) until 7 dpi, attenuates mechanical pain in hindlimbs at 3 weeks pi. We also evaluated the effects of B9 on the spontaneous recovery of locomotor function. We found that B9 alleviates mechanical pain but does not affect locomotor function. Importantly, B9 does not exacerbate lesion volume at the epicenter. In accordance with these findings, B9 does not aggravate glutamate-induced excitotoxic death of SC neurons in vitro. Moreover, SCI-induced increased astrocyte reactivity at the glial scar is not altered by B9 treatment. Our data suggest that B9 treatment reduces mechanical pain without exerting major detrimental effects following SCI.
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Affiliation(s)
- Nisha K Singh
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
- Molecular Biosciences Graduate Program, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
| | - Srinivasa R Gandu
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
- Molecular Biosciences Graduate Program, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
| | - Lun Li
- Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07101
| | - Li Ni
- Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07101
| | - Cigdem Acioglu
- Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07101
| | - Ersilia Mirabelli
- Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07101
| | - Liam L Hiester
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
| | - Stella Elkabes
- Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07101
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854
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Liu J, Kong W, Liu Y, Ma Q, Shao Q, Zeng L, Chao Y, Song X, Zhang J. Stage-Related Neurotoxicity of BPA in the Development of Zebrafish Embryos. TOXICS 2023; 11:toxics11020177. [PMID: 36851052 PMCID: PMC9963847 DOI: 10.3390/toxics11020177] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 06/10/2023]
Abstract
Bisphenol A (BPA) is one of the most widely produced chemicals in the world used in the production of epoxy resins and polycarbonate plastics. BPA is easily migrated from the outer packaging to the contents. Due to the lipophilic property, BPA is easily accumulated in organisms. Perinatal low-dose BPA exposure alters brain neural development in later generations. In this study, after BPA treatment, the spontaneous movement of zebrafish larvae from the cleavage period to the segmentation period (1-24 hpf) was significantly decreased, with speed decreasing by 18.97% and distance decreasing between 18.4 and 29.7% compared to controls. Transcriptomics analysis showed that 131 genes were significantly differentially expressed in the exposed group during the 1-24 hpf period, among which 39 genes were significantly upregulated and 92 genes were significantly downregulated. The GO enrichment analysis, gene function analysis and real-time quantitative PCR of differentially expressed genes showed that the mRNA level of guanine deaminase (cypin) decreased significantly in the 1-24 hpf period. Moreover, during the 1-24 hpf period, BPA exposure reduced guanine deaminase activity. Therefore, we confirmed that cypin is a key sensitive gene for BPA during this period. Finally, the cypin mRNA microinjection verified that the cypin level of zebrafish larvae was restored, leading to the restoration of the locomotor activity. Taken together, the current results show that the sensitive period of BPA to zebrafish embryos is from the cleavage period to the segmentation period (1-24 hpf), and cypin is a potential target for BPA-induced neurodevelopmental toxicity. This study provides a potential sensitive period and a potential target for the deep understanding of neurodevelopmental toxicity mechanisms caused by BPA.
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Zuccarini M, Pruccoli L, Balducci M, Giuliani P, Caciagli F, Ciccarelli R, Di Iorio P. Influence of Guanine-Based Purines on the Oxidoreductive Reactions Involved in Normal or Altered Brain Functions. J Clin Med 2023; 12:jcm12031172. [PMID: 36769818 PMCID: PMC9917437 DOI: 10.3390/jcm12031172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/23/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
The production of reactive oxygen species (ROS) in the brain is homeostatically controlled and contributes to normal neural functions. Inefficiency of control mechanisms in brain aging or pathological conditions leads to ROS overproduction with oxidative neural cell damage and degeneration. Among the compounds showing therapeutic potential against neuro-dysfunctions induced by oxidative stress are the guanine-based purines (GBPs), of which the most characterized are the nucleoside guanosine (GUO) and the nucleobase guanine (GUA), which act differently. Indeed, the administration of GUO to in vitro or in vivo models of acute brain injury (ischemia/hypoxia or trauma) or chronic neurological/neurodegenerative disorders, exerts neuroprotective and anti-inflammatory effects, decreasing the production of reactive radicals and improving mitochondrial function via multiple molecular signals. However, GUO administration to rodents also causes an amnesic effect. In contrast, the metabolite, GUA, could be effective in memory-related disorders by transiently increasing ROS production and stimulating the nitric oxide/soluble guanylate cyclase/cGMP/protein kinase G cascade, which has long been recognized as beneficial for cognitive function. Thus, it is worth pursuing further studies to ascertain the therapeutic role of GUO and GUA and to evaluate the pathological brain conditions in which these compounds could be more usefully used.
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Affiliation(s)
- Mariachiara Zuccarini
- Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, Via dei Vestini 29, 66100 Chieti, Italy
- Center for Advanced Studies and Technologies (CAST), University of Chieti-Pescara, Via L. Polacchi, 66100 Chieti, Italy
| | - Letizia Pruccoli
- Department for Life Quality Studies, Alma Mater Studiorum-University of Bologna, 47921 Rimini, Italy
| | - Martina Balducci
- Department for Life Quality Studies, Alma Mater Studiorum-University of Bologna, 47921 Rimini, Italy
| | - Patricia Giuliani
- Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, Via dei Vestini 29, 66100 Chieti, Italy
- Center for Advanced Studies and Technologies (CAST), University of Chieti-Pescara, Via L. Polacchi, 66100 Chieti, Italy
| | - Francesco Caciagli
- Center for Advanced Studies and Technologies (CAST), University of Chieti-Pescara, Via L. Polacchi, 66100 Chieti, Italy
| | - Renata Ciccarelli
- Center for Advanced Studies and Technologies (CAST), University of Chieti-Pescara, Via L. Polacchi, 66100 Chieti, Italy
| | - Patrizia Di Iorio
- Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, Via dei Vestini 29, 66100 Chieti, Italy
- Center for Advanced Studies and Technologies (CAST), University of Chieti-Pescara, Via L. Polacchi, 66100 Chieti, Italy
- Correspondence:
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4
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Sweet ES, Lange KR, Fenner MR, Tseng CY, Akum BF, Firestein BL. Cypin binds to tubulin heterodimers and microtubule protofilaments and regulates microtubule spacing in developing hippocampal neurons. Mol Cell Neurosci 2022; 123:103783. [PMID: 36208859 DOI: 10.1016/j.mcn.2022.103783] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 09/20/2022] [Accepted: 09/30/2022] [Indexed: 11/07/2022] Open
Abstract
Cytosolic PSD-95 interactor (cypin) is a multifunctional, guanine deaminase that plays a major role in shaping the morphology of the dendritic arbor of hippocampal and cortical neurons. Cypin catalyzes the Zn2+-dependent deamination of guanine to xanthine, which is then metabolized to uric acid by xanthine oxidase. Cypin binds to tubulin heterodimers via its carboxyl terminal region (amino acids (aa) 350-454), which contains a collapsin response mediator protein (CRMP) homology domain (aa 350-403). Moreover, this region alone is not sufficient to facilitate microtubule polymerization; therefore, additional cypin regions must be involved in this process. Here, we asked whether cypin binds to fully formed microtubules and how overexpression of cypin regulates the microtubule cytoskeleton in dendrites of cultured hippocampal neurons. Protein-protein docking strategies confirm that the cypin homodimer binds to tubulin heterodimers via amino acids within aa 350-454. Biochemical pull-down data suggest that aa 1-220 are necessary for cypin binding to soluble tubulin heterodimers and to taxol-stabilized microtubules. Molecular docking of the cypin homodimer to soluble tubulin heterodimers reveals a consistently observed docking pose using aa 47-71, 113-118, 174-178, and 411-418, which is consistent with our biochemical data. Additionally, overexpression of cypin in hippocampal neurons results in decreased spacing between microtubules. Our results suggest that several protein domains facilitate cypin-mediated polymerization of tubulin heterodimers into microtubules, possibly through a mechanism whereby cypin dimers bind to multiple tubulin heterodimers.
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Affiliation(s)
- Eric S Sweet
- Department of Biology, West Chester University, West Chester, PA, United States of America
| | - Keith R Lange
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, United States of America; Molecular Biosciences Graduate Program, Rutgers, The State University of New Jersey, Piscataway, NJ, United States of America
| | - Madeleine R Fenner
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, United States of America
| | - Chia-Yi Tseng
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, United States of America; Neurosciences Graduate Program, Rutgers, The State University of New Jersey, Piscataway, NJ, United States of America
| | - Barbara F Akum
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, United States of America; Molecular Biosciences Graduate Program, Rutgers, The State University of New Jersey, Piscataway, NJ, United States of America
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, United States of America.
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5
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Rodríguez AR, O'Neill KM, Swiatkowski P, Patel MV, Firestein BL. Overexpression of cypin alters dendrite morphology, single neuron activity, and network properties via distinct mechanisms. J Neural Eng 2019; 15:016020. [PMID: 29091046 DOI: 10.1088/1741-2552/aa976a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE This study investigates the effect that overexpression of cytosolic PSD-95 interactor (cypin), a regulator of synaptic PSD-95 protein localization and a core regulator of dendrite branching, exerts on the electrical activity of rat hippocampal neurons and networks. APPROACH We cultured rat hippocampal neurons and used lipid-mediated transfection and lentiviral gene transfer to achieve high levels of cypin or cypin mutant (cypinΔPDZ; PSD-95 non-binding) expression cellularly and network-wide, respectively. MAIN RESULTS Our analysis revealed that although overexpression of cypin and cypinΔPDZ increase dendrite numbers and decrease spine density, cypin and cypinΔPDZ distinctly regulate neuronal activity. At the single cell level, cypin promotes decreases in bursting activity while cypinΔPDZ reduces sEPSC frequency and further decreases bursting compared to cypin. At the network level, by using the Fano factor as a measure of spike count variability, cypin overexpression results in an increase in variability of spike count, and this effect is abolished when cypin cannot bind PSD-95. This variability is also dependent on baseline activity levels and on mean spike rate over time. Finally, our spike sorting data show that overexpression of cypin results in a more complex distribution of spike waveforms and that binding to PSD-95 is essential for this complexity. SIGNIFICANCE Our data suggest that dendrite morphology does not play a major role in cypin action on electrical activity.
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Affiliation(s)
- Ana R Rodríguez
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854, United States of America. Graduate Program in Biomedical Engineering, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, United States of America
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6
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Swiatkowski P, Sewell E, Sweet ES, Dickson S, Swanson RA, McEwan SA, Cuccolo N, McDonnell ME, Patel MV, Varghese N, Morrison B, Reitz AB, Meaney DF, Firestein BL. Cypin: A novel target for traumatic brain injury. Neurobiol Dis 2018; 119:13-25. [PMID: 30031156 DOI: 10.1016/j.nbd.2018.07.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/06/2018] [Accepted: 07/17/2018] [Indexed: 12/13/2022] Open
Abstract
Cytosolic PSD-95 interactor (cypin), the primary guanine deaminase in the brain, plays key roles in shaping neuronal circuits and regulating neuronal survival. Despite this pervasive role in neuronal function, the ability for cypin activity to affect recovery from acute brain injury is unknown. A key barrier in identifying the role of cypin in neurological recovery is the absence of pharmacological tools to manipulate cypin activity in vivo. Here, we use a small molecule screen to identify two activators and one inhibitor of cypin's guanine deaminase activity. The primary screen identified compounds that change the initial rate of guanine deamination using a colorimetric assay, and secondary screens included the ability of the compounds to protect neurons from NMDA-induced injury and NMDA-induced decreases in frequency and amplitude of miniature excitatory postsynaptic currents. Hippocampal neurons pretreated with activators preserved electrophysiological function and survival after NMDA-induced injury in vitro, while pretreatment with the inhibitor did not. The effects of the activators were abolished when cypin was knocked down. Administering either cypin activator directly into the brain one hour after traumatic brain injury significantly reduced fear conditioning deficits 5 days after injury, while delivering the cypin inhibitor did not improve outcome after TBI. Together, these data demonstrate that cypin activation is a novel approach for improving outcome after TBI and may provide a new pathway for reducing the deficits associated with TBI in patients.
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Affiliation(s)
- Przemyslaw Swiatkowski
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, USA; Graduate Program in Molecular Biosciences, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, USA
| | - Emily Sewell
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104-6391, USA
| | - Eric S Sweet
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, USA; Graduate Program in Neurosciences, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, USA
| | - Samantha Dickson
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104-6391, USA
| | - Rachel A Swanson
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, USA
| | - Sara A McEwan
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, USA; Graduate Program in Neurosciences, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, USA
| | - Nicholas Cuccolo
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, USA
| | - Mark E McDonnell
- Fox Chase Chemical Diversity Center, Inc., Doylestown, PA 18902, USA
| | - Mihir V Patel
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, USA; Graduate Program in Neurosciences, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, USA
| | - Nevin Varghese
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
| | - Barclay Morrison
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
| | - Allen B Reitz
- Fox Chase Chemical Diversity Center, Inc., Doylestown, PA 18902, USA
| | - David F Meaney
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104-6391, USA
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, USA.
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7
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A Novel Short Isoform of Cytosolic PSD-95 Interactor (Cypin) Regulates Neuronal Development. Mol Neurobiol 2018; 55:6269-6281. [PMID: 29294243 DOI: 10.1007/s12035-017-0849-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 12/19/2017] [Indexed: 10/18/2022]
Abstract
The guanine deaminase cypin (cytosolic PSD-95 interactor) binds to PSD-95 (postsynaptic density protein 95) and regulates dendrite branching by promoting microtubule polymerization. Here, we identify a novel short isoform of cypin, termed cypinS, which is expressed in mouse and human, but not rat, tissues. Cypin and cypinS mRNA and protein levels peak at P7 and P14 in the mouse brain, suggesting a role for these isoforms during development. Interestingly, although cypinS lacks guanine deaminase activity, overexpression of cypinS increases dendrite branching. This increase occurs further away from soma than do increases resulting from overexpression of cypin. In contrast, overexpression of cypin, but not cypinS, decreases dendritic spine density and maturity. This suggests that changes to spines, but not to dendrites, may be dependent on guanine deaminase activity. Furthermore, overexpression of either cypin or cypinS increases miniature excitatory postsynaptic current (mEPSC) frequency, pointing to a presynaptic role for both isoforms. Interestingly, overexpression of cypinS results in a significantly greater increase in frequency than does overexpression of cypin. Thus, cypin and cypinS play distinct roles in neuronal development.
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8
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Distinct effects on the dendritic arbor occur by microbead versus bath administration of brain-derived neurotrophic factor. Cell Mol Life Sci 2017; 74:4369-4385. [PMID: 28698933 DOI: 10.1007/s00018-017-2589-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 06/15/2017] [Accepted: 07/06/2017] [Indexed: 12/18/2022]
Abstract
Proper communication among neurons depends on an appropriately formed dendritic arbor, and thus, aberrant changes to the arbor are implicated in many pathologies, ranging from cognitive disorders to neurodegenerative diseases. Due to the importance of dendritic shape to neuronal network function, the morphology of dendrites is tightly controlled and is influenced by both intrinsic and extrinsic factors. In this work, we examine how brain-derived neurotrophic factor (BDNF), one of the most well-studied extrinsic regulators of dendritic branching, affects the arbor when it is applied locally via microbeads to cultures of hippocampal neurons. We found that local application of BDNF increases both proximal and distal branching in a time-dependent manner and that local BDNF application attenuates pruning of dendrites that occurs with neuronal maturation. Additionally, we examined whether cytosolic PSD-95 interactor (cypin), an intrinsic regulator of dendritic branching, plays a role in these changes and found strong evidence for the involvement of cypin in BDNF-promoted increases in dendrites after 24 but not 48 h of application. This current study extends our previous work in which we found that bath application of BDNF for 72 h, but not shorter times, increases proximal dendrite branching and that this increase occurs through transcriptional regulation of cypin. Moreover, this current work illustrates how dendritic branching is regulated differently by the same growth factor depending on its spatial localization, suggesting a novel pathway for modulation of dendritic branching locally.
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9
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O'Neill KM, Akum BF, Dhawan ST, Kwon M, Langhammer CG, Firestein BL. Assessing effects on dendritic arborization using novel Sholl analyses. Front Cell Neurosci 2015; 9:285. [PMID: 26283921 PMCID: PMC4519774 DOI: 10.3389/fncel.2015.00285] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 07/13/2015] [Indexed: 01/12/2023] Open
Abstract
Determining the shape of cell-specific dendritic arbors is a tightly regulated process that occurs during development. When this regulation is aberrant, which occurs during disease or injury, alterations in dendritic shape result in changes to neural circuitry. There has been significant progress on characterizing extracellular and intrinsic factors that regulate dendrite number by our laboratory and others. Generally, changes to the dendritic arbor are assessed by Sholl analysis or simple dendrite counting. However, we have found that this general method often overlooks local changes to the arbor. Previously, we developed a program (titled Bonfire) to facilitate digitization of neurite morphology and subsequent Sholl analysis and to assess changes to root, intermediate, and terminal neurites. Here, we apply these different Sholl analyses, and a novel Sholl analysis, to uncover previously unknown changes to the dendritic arbor when we overexpress an important regulator of dendrite branching, cytosolic PSD-95 interactor (cypin), at two developmental time points. Our results suggest that standard Sholl analysis and simple dendrite counting are not sufficient for uncovering local changes to the dendritic arbor.
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Affiliation(s)
- Kate M O'Neill
- Department of Cell Biology and Neuroscience, Rutgers University Piscataway, NJ, USA ; Graduate Program in Biomedical Engineering, Rutgers University Piscataway, NJ, USA
| | - Barbara F Akum
- Department of Cell Biology and Neuroscience, Rutgers University Piscataway, NJ, USA
| | - Survandita T Dhawan
- Department of Cell Biology and Neuroscience, Rutgers University Piscataway, NJ, USA
| | - Munjin Kwon
- Department of Cell Biology and Neuroscience, Rutgers University Piscataway, NJ, USA
| | | | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers University Piscataway, NJ, USA
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10
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Bitra A, Biswas A, Anand R. Structural Basis of the Substrate Specificity of Cytidine Deaminase Superfamily Guanine Deaminase. Biochemistry 2013; 52:8106-14. [DOI: 10.1021/bi400818e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Aruna Bitra
- Department of Chemistry, Indian Institute of Technology, Mumbai 400076, India
| | - Anwesha Biswas
- Department of Chemistry, Indian Institute of Technology, Mumbai 400076, India
| | - Ruchi Anand
- Department of Chemistry, Indian Institute of Technology, Mumbai 400076, India
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11
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BDNF-promoted increases in proximal dendrites occur via CREB-dependent transcriptional regulation of cypin. J Neurosci 2011; 31:9735-45. [PMID: 21715638 DOI: 10.1523/jneurosci.6785-10.2011] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Alterations in dendrite branching and morphology are present in many neurodegenerative diseases. These variations disrupt postsynaptic transmission and affect neuronal communication. Thus, it is important to understand the molecular mechanisms that regulate dendritogenesis and how they go awry during disease states. Previously, our laboratory showed that cypin, a mammalian guanine deaminase, increases dendrite number when overexpressed and decreases dendrite number when knocked down in cultured hippocampal neurons. Here, we report that exposure to brain-derived neurotrophic factor (BDNF), an important mediator of dendrite arborization, for 72 h but not for 24 h or less increases cypin mRNA and protein levels in rat hippocampal neurons. BDNF signals through cypin to regulate dendrite number, since knocking down cypin blocks the effects of BDNF. Furthermore, BDNF increases cypin levels via mitogen-activated protein kinase and transcription-dependent signaling pathways. Moreover, the cypin promoter region contains putative conserved cAMP response element (CRE) regions, which we found can be recognized and activated by CRE-binding protein (CREB). In addition, exposure of the neurons to BDNF increased CREB binding to the cypin promoter and, in line with these data, expression of a dominant negative form of CREB blocked BDNF-promoted increases in cypin protein levels and proximal dendrite branches. Together, these studies suggest that BDNF increases neuronal cypin expression by the activation of CREB, increasing cypin transcription leading to increased protein expression, thus identifying a novel pathway by which BDNF shapes the dendrite network.
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12
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Langhammer CG, Previtera ML, Sweet ES, Sran SS, Chen M, Firestein BL. Automated Sholl analysis of digitized neuronal morphology at multiple scales: Whole cell Sholl analysis versus Sholl analysis of arbor subregions. Cytometry A 2011; 77:1160-8. [PMID: 20687200 DOI: 10.1002/cyto.a.20954] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The morphology of dendrites and the axon determines how a neuron processes and transmits information. Neurite morphology is frequently analyzed by Sholl analysis or by counting the total number of neurites and branch tips. However, the time and resources required to perform such analysis by hand is prohibitive for the processing of large data sets and introduces problems with data auditing and reproducibility. Furthermore, analyses performed by hand or using course-grained morphometric data extraction tools can obscure subtle differences in data sets because they do not store the data in a form that facilitates the application of multiple analytical tools. To address these shortcomings, we have developed a program (titled "Bonfire") to facilitate digitization of neurite morphology and subsequent Sholl analysis. Our program builds upon other available open-source morphological analysis tools by performing Sholl analysis on subregions of the neuritic arbor, enabling the detection of local level changes in dendrite and axon branching behavior. To validate this new tool, we applied Bonfire analysis to images of hippocampal neurons treated with 25 ng/ml brain-derived neurotrophic factor (BDNF) and untreated control neurons. Consistent with prior findings, conventional Sholl analysis revealed that global exposure to BDNF increases the number of neuritic intersections proximal to the soma. Bonfire analysis additionally uncovers that BDNF treatment affects both root processes and terminal processes with no effect on intermediate neurites. Taken together, our data suggest that global exposure of hippocampal neurons to BDNF results in a reorganization of neuritic segments within their arbors, but not necessarily a change in their number or length. These findings were only made possible by the neurite-specific Sholl data returned by Bonfire analysis.
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13
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Fernández JR, Sweet ES, Welsh WJ, Firestein BL. Identification of small molecule compounds with higher binding affinity to guanine deaminase (cypin) than guanine. Bioorg Med Chem 2010; 18:6748-55. [PMID: 20716488 DOI: 10.1016/j.bmc.2010.07.054] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 07/15/2010] [Accepted: 07/22/2010] [Indexed: 10/19/2022]
Abstract
Guanine deaminase (GDA; cypin) is an important metalloenzyme that processes the first step in purine catabolism, converting guanine to xanthine by hydrolytic deamination. In higher eukaryotes, GDA also plays an important role in the development of neuronal morphology by regulating dendritic arborization. In addition to its role in the maturing brain, GDA is thought to be involved in proper liver function since increased levels of GDA activity have been correlated with liver disease and transplant rejection. Although mammalian GDA is an attractive and potential drug target for treatment of both liver diseases and cognitive disorders, prospective novel inhibitors and/or activators of this enzyme have not been actively pursued. In this study, we employed the combination of protein structure analysis and experimental kinetic studies to seek novel potential ligands for human guanine deaminase. Using virtual screening and biochemical analysis, we identified common small molecule compounds that demonstrate a higher binding affinity to GDA than does guanine. In vitro analysis demonstrates that these compounds inhibit guanine deamination, and more surprisingly, affect GDA (cypin)-mediated microtubule assembly. The results in this study provide evidence that an in silico drug discovery strategy coupled with in vitro validation assays can be successfully implemented to discover compounds that may possess therapeutic value for the treatment of diseases and disorders where GDA activity is abnormal.
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Affiliation(s)
- José R Fernández
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ 08854-8082, USA
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Oelschlaeger P, Ai N, Duprez KT, Welsh WJ, Toney JH. Evolving carbapenemases: can medicinal chemists advance one step ahead of the coming storm? J Med Chem 2010; 53:3013-27. [PMID: 20121112 DOI: 10.1021/jm9012938] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Peter Oelschlaeger
- Chemistry Department and Center for Macromolecular Modeling and Materials Design, California State Polytechnic University, Pomona, California, USA.
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15
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Abstract
Melamine toxicity in mammals has been attributed to the blockage of kidney tubules by insoluble complexes of melamine with cyanuric acid or uric acid. Bacteria metabolize melamine via three consecutive deamination reactions to generate cyanuric acid. The second deamination reaction, in which ammeline is the substrate, is common to many bacteria, but the genes and enzymes responsible have not been previously identified. Here, we combined bioinformatics and experimental data to identify guanine deaminase as the enzyme responsible for this biotransformation. The ammeline degradation phenotype was demonstrated in wild-type Escherichia coli and Pseudomonas strains, including E. coli K12 and Pseudomonas putida KT2440. Bioinformatics analysis of these and other genomes led to the hypothesis that the ammeline deaminating enzyme was guanine deaminase. An E. coli guanine deaminase deletion mutant was deficient in ammeline deaminase activity, supporting the role of guanine deaminase in this reaction. Two guanine deaminases from disparate sources (Bradyrhizobium japonicum USDA 110 and Homo sapiens) that had available X-ray structures were purified to homogeneity and shown to catalyze ammeline deamination at rates sufficient to support bacterial growth on ammeline as a sole nitrogen source. In silico models of guanine deaminase active sites showed that ammeline could bind to guanine deaminase in a similar orientation to guanine, with a favorable docking score. Other members of the amidohydrolase superfamily that are not guanine deaminases were assayed in vitro, and none had substantial ammeline deaminase activity. The present study indicated that widespread guanine deaminases have a promiscuous activity allowing them to catalyze a key reaction in the bacterial transformation of melamine to cyanuric acid and potentially contribute to the toxicity of melamine.
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Fernández JR, Byrne B, Firestein BL. Phylogenetic analysis and molecular evolution of guanine deaminases: from guanine to dendrites. J Mol Evol 2009; 68:227-35. [PMID: 19221682 DOI: 10.1007/s00239-009-9205-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 10/30/2008] [Accepted: 01/21/2009] [Indexed: 01/02/2023]
Abstract
Guanine deaminase (GDA; guanase) is a ubiquitous enzyme that catalyzes the first step of purine metabolism by hydrolytic deamination of guanine, resulting in the production of xanthine. This hydrolase subfamily member plays an essential role in maintaining homeostasis of cellular triphosphate nucleotides for energy, signal transduction pathways, and nitrogen sources. In mammals, GDA protein levels can play a role in neuronal development by regulating dendritic arborization. We previously demonstrated that the most abundant alternative splice form of GDA in mammals, termed cypin (cytosolic PSD-95 interactor), interacts with postsynaptic density proteins, regulates microtubule polymerization, and increases dendrite number. Since purine metabolism and dendrite development were previously thought to be independent cellular processes, this multifunctional protein serves as a new target for the treatment of cognitive disorders characterized by aberrant neuronal morphology and purine metabolism. Although the enzymatic activity of GDA has been conserved during evolution from prokaryotes to higher eukaryotes, a detailed evolutionary assessment of the principal domains in GDA proteins has not yet been put forward. In this study, we perform a complete evolutionary analysis of the full-length sequences and the principal domains in guanine deaminases. Furthermore, we reconstruct the molecular phylogeny of guanine deaminases with neighbor-joining, maximum-likelihood, and UPGMA methods of phylogenetic inference. This study can act as a model whereby a universal housekeeping enzyme may be adapted to act also as a key regulator of a developmental process.
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Affiliation(s)
- José R Fernández
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Nelson Biological Laboratories, 604 Allison Road, Piscataway, NJ 08854-8082, USA
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