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Yu B, Chen J, Wang Y, Zhou J, Wang H, Li H, Cai T, Huang R, Zhou Y, Ma J. Vitamin A influences the incretin hormone profiles by activating the retinoic acid receptor β. J Diabetes Complications 2024; 38:108806. [PMID: 38996583 DOI: 10.1016/j.jdiacomp.2024.108806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 06/30/2024] [Accepted: 07/06/2024] [Indexed: 07/14/2024]
Abstract
BACKGROUND This study aimed to investigate the impact of Vitamin A (VA) on intestinal glucose metabolic phenotypes. METHODS Male C57BL/6 mice were randomized assigned to a VA-normal diet (VAN) or a VA-deficient diet (VAD) for 12 weeks. After12 weeks, the VAD mice were given 30 IU/g/d retinol for 10 days and VAN diet (VADN) for 10 weeks. By using glucose tolerance tests, immunofluorescence staining, quantitative polymerase chain reaction, siRNA transduction, and enzyme-linked immunosorbent assay, the glucose metabolic phenotypes as well as secretory function and intracellular hormone changes of STC-1 were assessed. RESULTS VAD mice showed a decrease of glucose-stimulated insulin secretion and a loss of intestinal glucagon-like peptide-1 (GLP-1) expression. Through reintroducing dietary VA to VAD mice, the intestinal VA levels, GLP-1 expression and normal glucose can be restored. The incubation with retinol increased VA signaling factors expression within STC-1 cells, especially retinoic acid receptor β (RARβ). The activation of RARβ restored intracellular incretin hormone synthesis and secretory function. CONCLUSIONS VA deficiency leads to an imbalance of intestinal glucose metabolic phenotypes through a mechanism involving RARβ signaling pathway, suggesting a new method to achieve the treatment for VAD induced glucose metabolism impairment.
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Affiliation(s)
- Baowen Yu
- Department of Endocrinology, Nanjing Medical University affiliated Nanjing Hospital: Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Jie Chen
- Department of Personnel Management, Nanjing Medical University affiliated Nanjing Hospital: Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Yuming Wang
- Department of Endocrinology, Nanjing Medical University affiliated Nanjing Hospital: Nanjing First Hospital, Nanjing Medical University, Nanjing, China; Department of Gerontology, Drum tower hospital, Medical School of Nanjing University, Nanjing, China
| | - Junming Zhou
- Department of Cadre Gastroenterology, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Huiying Wang
- Department of Endocrinology, Nanjing Medical University affiliated Nanjing Hospital: Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Huiqin Li
- Department of Endocrinology, Nanjing Medical University affiliated Nanjing Hospital: Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Tingting Cai
- Department of Endocrinology, Nanjing Medical University affiliated Nanjing Hospital: Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Rong Huang
- Department of Endocrinology, Nanjing Medical University affiliated Nanjing Hospital: Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Yunting Zhou
- Department of Endocrinology, Nanjing Medical University affiliated Nanjing Hospital: Nanjing First Hospital, Nanjing Medical University, Nanjing, China.
| | - Jianhua Ma
- Department of Endocrinology, Nanjing Medical University affiliated Nanjing Hospital: Nanjing First Hospital, Nanjing Medical University, Nanjing, China.
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Goncalves MB, Mant T, Täubel J, Clarke E, Hassanin H, Bendel D, Fok H, Posner J, Holmes J, Mander AP, Corcoran JPT. Phase 1 safety, tolerability, pharmacokinetics and pharmacodynamic results of KCL-286, a novel retinoic acid receptor-β agonist for treatment of spinal cord injury, in male healthy participants. Br J Clin Pharmacol 2023; 89:3573-3583. [PMID: 37452623 PMCID: PMC10835503 DOI: 10.1111/bcp.15854] [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: 04/20/2023] [Revised: 06/23/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023] Open
Abstract
AIMS KCL-286 is an orally available agonist that activates the retinoic acid receptor (RAR) β2, a transcription factor which stimulates axonal outgrowth. The investigational medicinal product is being developed for treatment of spinal cord injury (SCI). This adaptive dose escalation study evaluated the tolerability, safety and pharmacokinetics and pharmacodynamic activity of KCL-286 in male healthy volunteers to establish dosing to be used in the SCI patient population. METHODS The design was a double blind, randomized, placebo-controlled dose escalation study in 2 parts: a single ascending dose adaptive design with a food interaction arm, and a multiple ascending dose design. RARβ2 mRNA expression was evaluated in white blood cells. RESULTS At the highest single and multiple ascending doses (100 mg), no trends or clinically important differences were noted in the incidence or intensity of adverse events (AEs), serious AEs or other safety assessments with none leading to withdrawal from the study. The AEs were dry skin, rash, skin exfoliation, raised liver enzymes and eye disorders. There was an increase in mean maximum observed concentration and area under the plasma concentration-time curve up to 24 h showing a trend to subproportionality with dose. RARβ2 was upregulated by the investigational medicinal product in white blood cells. CONCLUSION KCL-286 was well tolerated by healthy human participants following doses that exceeded potentially clinically relevant plasma exposures based on preclinical in vivo models. Target engagement shows the drug candidate activates its receptor. These findings support further development of KCL-286 as a novel oral treatment for SCI.
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Affiliation(s)
- Maria B. Goncalves
- Neuroscience Drug Discovery UnitThe Wolfson Centre for Age‐Related Diseases, King's College London, Guy's CampusLondonUK
| | - Tim Mant
- NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust and King's College London, Guy's and St Thomas' NHS Foundation TrustLondonUK
| | | | - Earl Clarke
- Neuroscience Drug Discovery UnitThe Wolfson Centre for Age‐Related Diseases, King's College London, Guy's CampusLondonUK
| | - Hana Hassanin
- Surrey Clinical Research CentreUniversity of SurreySurreyUK
| | - Daryl Bendel
- Surrey Clinical Research CentreUniversity of SurreySurreyUK
| | - Henry Fok
- NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust and King's College London, Guy's and St Thomas' NHS Foundation TrustLondonUK
| | - John Posner
- Centre for Pharmaceutical Medicine Research, Institute of Pharmaceutical ScienceKing's College LondonLondonUK
| | - Jane Holmes
- Nuffield Department of Primary Care Health SciencesUniversity of OxfordOxfordUK
| | | | - Jonathan P. T. Corcoran
- Neuroscience Drug Discovery UnitThe Wolfson Centre for Age‐Related Diseases, King's College London, Guy's CampusLondonUK
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Atta A, Gupta A, Choudhary P, Dwivedi S, Singh S. Inhibition of LINGO1 as a therapeutic target to promote axonal regeneration and repair for neurological disorders. 3 Biotech 2023; 13:372. [PMID: 37854938 PMCID: PMC10579209 DOI: 10.1007/s13205-023-03789-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 09/23/2023] [Indexed: 10/20/2023] Open
Abstract
The Central nervous system is blemished by the high incidence of neurodegenerative diseases, which is known to cause disfiguration of regeneration and repair of axonal growth. Recognition of proteins that act as agents of repressing such repair has become the norm to tackle these abominable conditions. One such protein is LINGO1 that act as a repressor for axonal growth. Being one of the critical causative agents of several neurodegenerative pathways. Consequently, its inhibition may tend to help the outcomes of regenerative technologies aiming to outweigh the symptoms of neurodegenerative diseases. For this objective, LINGO1 was targeted with pharmacophore analogs of Fasudil and Ibuprofen, as they are known to have a deterring effect against the concerned protein. 1-Tosyl-2-(chloromethyl)-2,3-dihydro-1H-indole was found showing the least binding score of - 6.8, with verified ADMET admissibility. The pharmacological activity of the said ligand was estimated with QSAR tool showing favourable electro-steric model. All this was finally collaborated with a molecular dynamics simulation study which exhibited a stable structure compatibility of the ligand with LINGO-1. Further, the efficacy of the compound can be evaluated through experimental studies for inferring its future potential and utilization as an effective means to tackle neuronal regeneration and remyleination. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-023-03789-4.
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Affiliation(s)
- Avik Atta
- Applied Science Department, Indian Institute of Information Technology, Allahabad, Devghat, Jhalwa, Prayagraj, 211015 Uttar Pradesh India
| | - Ayushi Gupta
- Applied Science Department, Indian Institute of Information Technology, Allahabad, Devghat, Jhalwa, Prayagraj, 211015 Uttar Pradesh India
| | - Princy Choudhary
- Applied Science Department, Indian Institute of Information Technology, Allahabad, Devghat, Jhalwa, Prayagraj, 211015 Uttar Pradesh India
| | - Shrey Dwivedi
- Applied Science Department, Indian Institute of Information Technology, Allahabad, Devghat, Jhalwa, Prayagraj, 211015 Uttar Pradesh India
| | - Sangeeta Singh
- Applied Science Department, Indian Institute of Information Technology, Allahabad, Devghat, Jhalwa, Prayagraj, 211015 Uttar Pradesh India
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Kitamura N, Fujiwara N, Hayakawa K, Ohama T, Sato K. Protein phosphatase 6 promotes neurite outgrowth by promoting mTORC2 activity in N2a cells. J Biochem 2021; 170:131-138. [PMID: 34314486 DOI: 10.1093/jb/mvab028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/08/2021] [Indexed: 11/14/2022] Open
Abstract
Understanding the molecular mechanism of neuronal differentiation is important to overcome the incurable diseases caused by nervous system damage. Neurite outgrowth is prerequisite for neuronal differentiation and regeneration, and cAMP response element-binding protein (CREB) is one of the major transcriptional factors positively regulating this process. Neuronal differentiation stimuli activate mammalian target of rapamycin (mTOR) complex 2 (mTORC2)/Akt signaling to phosphorylate CREB, however, the precise molecular mechanism of this event has not been fully understood. In this manuscript, we show that neuronal differentiation stimuli increased a protein level of protein phosphatase 6 (PP6), a member of type 2A Ser/Thr protein phosphatases. PP6 knockdown suppressed mTORC2/Akt/CREB signaling and results in failure of neurite outgrowth. SIN1 is a unique component of mTORC2 that enhances mTORC2 activity toward Akt when it is in dephosphorylated form. We found PP6 knockdown increased SIN1 phosphorylation. These data suggest that PP6 may positively regulate neurite outgrowth by dephosphorylating SIN1 to activate mTORC2/Akt/CREB signaling.
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Affiliation(s)
- Nao Kitamura
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | | | - Koji Hayakawa
- Department of Toxicology, Faculty of Veterinary Medicine, Okayama University of Science, 1-3 Ikoinooka, Imabari, 794-8555 Ehime, Japan
| | - Takashi Ohama
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Koichi Sato
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
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Koutelou E, Farria AT, Dent SYR. Complex functions of Gcn5 and Pcaf in development and disease. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194609. [PMID: 32730897 DOI: 10.1016/j.bbagrm.2020.194609] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 12/12/2022]
Abstract
A wealth of biochemical and cellular data, accumulated over several years by multiple groups, has provided a great degree of insight into the molecular mechanisms of actions of GCN5 and PCAF in gene activation. Studies of these lysine acetyltransferases (KATs) in vitro, in cultured cells, have revealed general mechanisms for their recruitment by sequence-specific binding factors and their molecular functions as transcriptional co-activators. Genetic studies indicate that GCN5 and PCAF are involved in multiple developmental processes in vertebrates, yet our understanding of their molecular functions in these contexts remains somewhat rudimentary. Understanding the functions of GCN5/PCAF in developmental processes provides clues to the roles of these KATs in disease states. Here we will review what is currently known about the developmental roles of GCN5 and PCAF, as well as emerging role of these KATs in oncogenesis.
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Affiliation(s)
- Evangelia Koutelou
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, United States of America; Center for Cancer Epigenetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States of America
| | - Aimee T Farria
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, United States of America; Center for Cancer Epigenetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States of America
| | - Sharon Y R Dent
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, United States of America; Center for Cancer Epigenetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States of America.
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Huang YQ, Peng ZR, Huang FL, Yang AL. Mechanism of delayed encephalopathy after acute carbon monoxide poisoning. Neural Regen Res 2020; 15:2286-2295. [PMID: 32594050 PMCID: PMC7749483 DOI: 10.4103/1673-5374.284995] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Many hypotheses exist regarding the mechanism underlying delayed encephalopathy after acute carbon monoxide poisoning (DEACMP), including the inflammation and immune-mediated damage hypothesis and the cellular apoptosis and direct neuronal toxicity hypothesis; however, no existing hypothesis provides a satisfactory explanation for the complex clinical processes observed in DEACMP. Leucine-rich repeat and immunoglobulin-like domain-containing protein-1 (LINGO-1) activates the Ras homolog gene family member A (RhoA)/Rho-associated coiled-coil containing protein kinase 2 (ROCK2) signaling pathway, which negatively regulates oligodendrocyte myelination, axonal growth, and neuronal survival, causing myelin damage and participating in the pathophysiological processes associated with many central nervous system diseases. However, whether LINGO-1 is involved in DEACMP remains unclear. A DEACMP model was established in rats by allowing them to inhale 1000 ppm carbon monoxide gas for 40 minutes, followed by 3000 ppm carbon monoxide gas for an additional 20 minutes. The results showed that compared with control rats, DEACMP rats showed significantly increased water maze latency and increased protein and mRNA expression levels of LINGO-1, RhoA, and ROCK2 in the brain. Compared with normal rats, significant increases in injured neurons in the hippocampus and myelin sheath damage in the lateral geniculate body were observed in DEACMP rats. From days 1 to 21 after DEACMP, the intraperitoneal injection of retinoic acid (10 mg/kg), which can inhibit LINGO-1 expression, was able to improve the above changes observed in the DEACMP model. Therefore, the overexpression of LINGO-1 appeared to increase following carbon monoxide poisoning, activating the RhoA/ROCK2 signaling pathway, which may be an important pathophysiological mechanism underlying DEACMP. This study was reviewed and approved by the Medical Ethics Committee of Xiangya Hospital of Central South Hospital (approval No. 201612684) on December 26, 2016.
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Affiliation(s)
- Yan-Qing Huang
- Department of Hyperbaric Oxygen, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Zheng-Rong Peng
- Department of Hyperbaric Oxygen, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Fang-Ling Huang
- Department of Hyperbaric Oxygen, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - A-Li Yang
- Department of Hyperbaric Oxygen, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
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7
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Hervera A, Zhou L, Palmisano I, McLachlan E, Kong G, Hutson TH, Danzi MC, Lemmon VP, Bixby JL, Matamoros‐Angles A, Forsberg K, De Virgiliis F, Matheos DP, Kwapis J, Wood MA, Puttagunta R, del Río JA, Di Giovanni S. PP4-dependent HDAC3 dephosphorylation discriminates between axonal regeneration and regenerative failure. EMBO J 2019; 38:e101032. [PMID: 31268609 PMCID: PMC6600644 DOI: 10.15252/embj.2018101032] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 04/15/2019] [Accepted: 04/17/2019] [Indexed: 01/01/2023] Open
Abstract
The molecular mechanisms discriminating between regenerative failure and success remain elusive. While a regeneration-competent peripheral nerve injury mounts a regenerative gene expression response in bipolar dorsal root ganglia (DRG) sensory neurons, a regeneration-incompetent central spinal cord injury does not. This dichotomic response offers a unique opportunity to investigate the fundamental biological mechanisms underpinning regenerative ability. Following a pharmacological screen with small-molecule inhibitors targeting key epigenetic enzymes in DRG neurons, we identified HDAC3 signalling as a novel candidate brake to axonal regenerative growth. In vivo, we determined that only a regenerative peripheral but not a central spinal injury induces an increase in calcium, which activates protein phosphatase 4 that in turn dephosphorylates HDAC3, thus impairing its activity and enhancing histone acetylation. Bioinformatics analysis of ex vivo H3K9ac ChIPseq and RNAseq from DRG followed by promoter acetylation and protein expression studies implicated HDAC3 in the regulation of multiple regenerative pathways. Finally, genetic or pharmacological HDAC3 inhibition overcame regenerative failure of sensory axons following spinal cord injury. Together, these data indicate that PP4-dependent HDAC3 dephosphorylation discriminates between axonal regeneration and regenerative failure.
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Affiliation(s)
- Arnau Hervera
- Department of MedicineDivision of Brain SciencesMolecular NeuroregenerationImperial College LondonLondonUK
- Molecular and Cellular NeurobiotechnologyInstitute for Bioengineering of Catalonia (IBEC)Parc Científic de BarcelonaBarcelonaSpain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)BarcelonaSpain
- Department of Cell Biology, Physiology and ImmunologyUniversitat de BarcelonaBarcelonaSpain
- Institute of NeuroscienceUniversity of BarcelonaBarcelonaSpain
| | - Luming Zhou
- Department of MedicineDivision of Brain SciencesMolecular NeuroregenerationImperial College LondonLondonUK
- Laboratory for NeuroRegeneration and RepairCenter for NeurologyHertie Institute for Clinical Brain ResearchUniversity of TuebingenTuebingenGermany
- Graduate School for Cellular and Molecular NeuroscienceUniversity of TuebingenTuebingenGermany
| | - Ilaria Palmisano
- Department of MedicineDivision of Brain SciencesMolecular NeuroregenerationImperial College LondonLondonUK
| | - Eilidh McLachlan
- Department of MedicineDivision of Brain SciencesMolecular NeuroregenerationImperial College LondonLondonUK
| | - Guiping Kong
- Department of MedicineDivision of Brain SciencesMolecular NeuroregenerationImperial College LondonLondonUK
- Laboratory for NeuroRegeneration and RepairCenter for NeurologyHertie Institute for Clinical Brain ResearchUniversity of TuebingenTuebingenGermany
| | - Thomas H Hutson
- Department of MedicineDivision of Brain SciencesMolecular NeuroregenerationImperial College LondonLondonUK
| | - Matt C Danzi
- The Miami Project to Cure ParalysisDepartment of Neurological SurgeryMiller School of MedicineUniversity of MiamiMiamiFLUSA
| | - Vance P Lemmon
- The Miami Project to Cure ParalysisDepartment of Neurological SurgeryMiller School of MedicineUniversity of MiamiMiamiFLUSA
| | - John L Bixby
- The Miami Project to Cure ParalysisDepartment of Neurological SurgeryMiller School of MedicineUniversity of MiamiMiamiFLUSA
| | - Andreu Matamoros‐Angles
- Molecular and Cellular NeurobiotechnologyInstitute for Bioengineering of Catalonia (IBEC)Parc Científic de BarcelonaBarcelonaSpain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)BarcelonaSpain
- Department of Cell Biology, Physiology and ImmunologyUniversitat de BarcelonaBarcelonaSpain
- Institute of NeuroscienceUniversity of BarcelonaBarcelonaSpain
| | - Kirsi Forsberg
- Laboratory for NeuroRegeneration and RepairCenter for NeurologyHertie Institute for Clinical Brain ResearchUniversity of TuebingenTuebingenGermany
| | - Francesco De Virgiliis
- Department of MedicineDivision of Brain SciencesMolecular NeuroregenerationImperial College LondonLondonUK
- Laboratory for NeuroRegeneration and RepairCenter for NeurologyHertie Institute for Clinical Brain ResearchUniversity of TuebingenTuebingenGermany
- Graduate School for Cellular and Molecular NeuroscienceUniversity of TuebingenTuebingenGermany
| | - Dina P Matheos
- Center for the Neurobiology of Learning & MemoryDepartment of Neurobiology & BehaviorUniversity of CaliforniaIrvineCAUSA
| | - Janine Kwapis
- Center for the Neurobiology of Learning & MemoryDepartment of Neurobiology & BehaviorUniversity of CaliforniaIrvineCAUSA
| | - Marcelo A Wood
- Center for the Neurobiology of Learning & MemoryDepartment of Neurobiology & BehaviorUniversity of CaliforniaIrvineCAUSA
| | - Radhika Puttagunta
- Laboratory for NeuroRegeneration and RepairCenter for NeurologyHertie Institute for Clinical Brain ResearchUniversity of TuebingenTuebingenGermany
- Spinal Cord Injury CenterUniversity Hospital HeidelbergHeidelbergGermany
| | - José Antonio del Río
- Molecular and Cellular NeurobiotechnologyInstitute for Bioengineering of Catalonia (IBEC)Parc Científic de BarcelonaBarcelonaSpain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)BarcelonaSpain
- Department of Cell Biology, Physiology and ImmunologyUniversitat de BarcelonaBarcelonaSpain
- Institute of NeuroscienceUniversity of BarcelonaBarcelonaSpain
| | - Simone Di Giovanni
- Department of MedicineDivision of Brain SciencesMolecular NeuroregenerationImperial College LondonLondonUK
- Laboratory for NeuroRegeneration and RepairCenter for NeurologyHertie Institute for Clinical Brain ResearchUniversity of TuebingenTuebingenGermany
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Regulation of Myelination by Exosome Associated Retinoic Acid Release from NG2-Positive Cells. J Neurosci 2019; 39:3013-3027. [PMID: 30760627 PMCID: PMC6468108 DOI: 10.1523/jneurosci.2922-18.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 01/15/2019] [Accepted: 02/03/2019] [Indexed: 02/07/2023] Open
Abstract
In the CNS, oligodendrocytes are responsible for myelin formation and maintenance. Following spinal cord injury, oligodendrocyte loss and an inhibitory milieu compromise remyelination and recovery. Here, we explored the role of retinoic acid receptor-beta (RARβ) signaling in remyelination. Using a male Sprague Dawley rat model of PNS-CNS injury, we show that oral treatment with a novel drug like RARβ agonist, C286, induces neuronal expression of the proteoglycan decorin and promotes myelination and differentiation of oligodendrocyte precursor cells (NG2+ cells) in a decorin-mediated neuron–glia cross talk. Decorin promoted the activation of RARα in NG2+ cells by increasing the availability of the endogenous ligand RA. NG2+ cells synthesize RA, which is released in association with exosomes. We found that decorin prevents this secretion through regulation of the EGFR–calcium pathway. Using functional and pharmacological studies, we further show that RARα signaling is both required and sufficient for oligodendrocyte differentiation. These findings illustrate that RARβ and RARα are important regulators of oligodendrocyte differentiation, providing new targets for myelination. SIGNIFICANCE STATEMENT This study identifies novel therapeutic targets for remyelination after PNS-CNS injury. Pharmacological and knock-down experiments show that the retinoic acid (RA) signaling promotes differentiation of oligodendrocyte precursor cells (OPCs) and remyelination in a cross talk between neuronal RA receptor-beta (RARβ) and RARα in NG2+ cells. We show that stimulation of RARα is required for the differentiation of OPCs and we describe for the first time how oral treatment with a RARβ agonist (C286, currently being tested in a Phase 1 trial, ISRCTN12424734) leads to the endogenous synthesis of RA through retinaldehyde dehydrogenase 2 (Raldh2) in NG2 cells and controls exosome-associated-RA intracellular levels through a decorin–Ca2+ pathway. Although RARβ has been implicated in distinct aspects of CNS regeneration, this study identifies a novel function for both RARβ and RARα in remyelination.
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Chew LJ, DeBoy CA. Pharmacological approaches to intervention in hypomyelinating and demyelinating white matter pathology. Neuropharmacology 2016; 110:605-625. [PMID: 26116759 PMCID: PMC4690794 DOI: 10.1016/j.neuropharm.2015.06.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 06/10/2015] [Accepted: 06/17/2015] [Indexed: 12/17/2022]
Abstract
White matter disease afflicts both developing and mature central nervous systems. Both cell intrinsic and extrinsic dysregulation result in profound changes in cell survival, axonal metabolism and functional performance. Experimental models of developmental white matter (WM) injury and demyelination have not only delineated mechanisms of signaling and inflammation, but have also paved the way for the discovery of pharmacological approaches to intervention. These reagents have been shown to enhance protection of the mature oligodendrocyte cell, accelerate progenitor cell recruitment and/or differentiation, or attenuate pathological stimuli arising from the inflammatory response to injury. Here we highlight reports of studies in the CNS in which compounds, namely peptides, hormones, and small molecule agonists/antagonists, have been used in experimental animal models of demyelination and neonatal brain injury that affect aspects of excitotoxicity, oligodendrocyte development and survival, and progenitor cell function, and which have been demonstrated to attenuate damage and improve WM protection in experimental models of injury. The molecular targets of these agents include growth factor and neurotransmitter receptors, morphogens and their signaling components, nuclear receptors, as well as the processes of iron transport and actin binding. By surveying the current evidence in non-immune targets of both the immature and mature WM, we aim to better understand pharmacological approaches modulating endogenous oligodendroglia that show potential for success in the contexts of developmental and adult WM pathology. This article is part of the Special Issue entitled 'Oligodendrocytes in Health and Disease'.
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Affiliation(s)
- Li-Jin Chew
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC, USA.
| | - Cynthia A DeBoy
- Biology Department, Trinity Washington University, Washington, DC, USA
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10
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The MDM4/MDM2-p53-IGF1 axis controls axonal regeneration, sprouting and functional recovery after CNS injury. Brain 2015; 138:1843-62. [DOI: 10.1093/brain/awv125] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 03/09/2015] [Indexed: 12/20/2022] Open
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11
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Scapin G, Salice P, Tescari S, Menna E, De Filippis V, Filippini F. Enhanced neuronal cell differentiation combining biomimetic peptides and a carbon nanotube-polymer scaffold. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2015; 11:621-32. [DOI: 10.1016/j.nano.2014.11.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 10/10/2014] [Accepted: 11/07/2014] [Indexed: 12/28/2022]
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12
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Zhao XS, Fu WY, Hung KW, Chien WWY, Li Z, Fu AK, Ip NY. NRC-interacting factor directs neurite outgrowth in an activity-dependent manner. Neuroscience 2015; 289:207-13. [PMID: 25573434 DOI: 10.1016/j.neuroscience.2014.12.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 12/05/2014] [Accepted: 12/24/2014] [Indexed: 11/18/2022]
Abstract
Nuclear hormone receptor coregulator-interacting factor 1 (NIF-1) is a zinc finger nuclear protein that was initially identified to enhance nuclear hormone receptor transcription via its interaction with nuclear hormone receptor coregulator (NRC). NIF-1 may regulate gene transcription either by modulating general transcriptional machinery or remodeling chromatin structure through interactions with specific protein partners. We previously reported that the cytoplasmic/nuclear localization of NIF-1 is regulated by the neuronal Cdk5 activator p35, suggesting potential neuronal functions for NIF-1. The present study reveals that NIF-1 plays critical roles in regulating neuronal morphogenesis at early stages. NIF-1 was prominently expressed in the nuclei of developing rat cortical neurons. Knockdown of NIF-1 expression attenuated both neurite outgrowth in cultured cortical neurons and retinoic acid (RA)-treated Neuro-2a neuroblastoma cells. Furthermore, activity-induced Ca(2+) influx, which is critical for neuronal morphogenesis, stimulated the nuclear localization of NIF-1 in cortical neurons. Suppression of NIF-1 expression reduced the up-regulation of neuronal activity-dependent gene transcription. These findings collectively suggest that NIF-1 directs neuronal morphogenesis during early developmental stages through modulating activity-dependent gene transcription.
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Affiliation(s)
- X-S Zhao
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - W-Y Fu
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - K-W Hung
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - W W Y Chien
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Z Li
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - A K Fu
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - N Y Ip
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
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Xing HY, Meng EY, Xia YP, Peng H. Effect of retinoic acid on expression of LINGO-1 and neural regeneration after cerebral ischemia. ACTA ACUST UNITED AC 2015; 35:54-57. [PMID: 25673193 DOI: 10.1007/s11596-015-1388-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 11/13/2014] [Indexed: 01/26/2023]
Abstract
The purpose of this study was to observe the expression of LINGO-1 after cerebral ischemia, investigate the effects of retinoic acid (RA) on the expression of LINGO-1 and GAP-43, and the number of synapses, and to emplore the repressive effect of LINGO-1 on neural regeneration after cerebral ischemia. The model of permanent focal cerebral ischemia was established by the modified suture method of middle cerebral artery occlusion (MCAO) in Sprague-Dawley (SD) rats. The expression of LINGO-1 was detected by Western blotting and that of GAP-43 by immunohistochemistry. The number of synapses was observed by transmission electron microscopy. The SD rats were divided into three groups: sham operation (sham) group, cerebral ischemia (CI) group and RA treatment (RA) group. The results showed that the expression level of LINGO-1 at 7th day after MCAO in sham, CI and RA groups was 0.266 ± 0.019, 1.215 ± 0.063 and 0.702 ± 0.081, respectively (P<0.01). The number of Gap-43-positive nerve cells at 7th day after MCAO in sham, CI and RA group was 0, 59.08 ± 1.76 and 76.20 ± 3.12 per high power field, respectively (P<0.05). The number of synapses at 7th day after MCAO was 8.42 ± 0.13, 1.74 ± 0.37 and 5.39 ± 0.26 per μm², respectively (P<0.05). It is concluded that LINGO-1 expression is up-regulated after cerebral ischemia, and RA inhibits the expression of LINGO-1, promotes the expression of GAP-43 and increases the number of synapses. It suggests that LINGO-1 may be involved in the pathogenesis of cerebral ischemia, which may provide an experimenal basis for LINGO-1 antogonist, RA, for the treatment of cerebral ischemia.
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Affiliation(s)
- Hong-Yi Xing
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| | - Er-Yan Meng
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yuan-Peng Xia
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Hai Peng
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
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14
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Devanna P, Middelbeek J, Vernes SC. FOXP2 drives neuronal differentiation by interacting with retinoic acid signaling pathways. Front Cell Neurosci 2014; 8:305. [PMID: 25309332 PMCID: PMC4176457 DOI: 10.3389/fncel.2014.00305] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 09/10/2014] [Indexed: 11/14/2022] Open
Abstract
FOXP2 was the first gene shown to cause a Mendelian form of speech and language disorder. Although developmentally expressed in many organs, loss of a single copy of FOXP2 leads to a phenotype that is largely restricted to orofacial impairment during articulation and linguistic processing deficits. Why perturbed FOXP2 function affects specific aspects of the developing brain remains elusive. We investigated the role of FOXP2 in neuronal differentiation and found that FOXP2 drives molecular changes consistent with neuronal differentiation in a human model system. We identified a network of FOXP2 regulated genes related to retinoic acid signaling and neuronal differentiation. FOXP2 also produced phenotypic changes associated with neuronal differentiation including increased neurite outgrowth and reduced migration. Crucially, cells expressing FOXP2 displayed increased sensitivity to retinoic acid exposure. This suggests a mechanism by which FOXP2 may be able to increase the cellular differentiation response to environmental retinoic acid cues for specific subsets of neurons in the brain. These data demonstrate that FOXP2 promotes neuronal differentiation by interacting with the retinoic acid signaling pathway and regulates key processes required for normal circuit formation such as neuronal migration and neurite outgrowth. In this way, FOXP2, which is found only in specific subpopulations of neurons in the brain, may drive precise neuronal differentiation patterns and/or control localization and connectivity of these FOXP2 positive cells.
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Affiliation(s)
- Paolo Devanna
- Language and Genetics Department, Max Planck Institute for Psycholinguistics Nijmegen, Netherlands
| | - Jeroen Middelbeek
- Laboratory of Pediatric Oncology, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Netherlands
| | - Sonja C Vernes
- Language and Genetics Department, Max Planck Institute for Psycholinguistics Nijmegen, Netherlands ; Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Netherlands
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15
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PCAF-dependent epigenetic changes promote axonal regeneration in the central nervous system. Nat Commun 2014; 5:3527. [PMID: 24686445 DOI: 10.1038/ncomms4527] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 02/27/2014] [Indexed: 01/20/2023] Open
Abstract
Axonal regenerative failure is a major cause of neurological impairment following central nervous system (CNS) but not peripheral nervous system (PNS) injury. Notably, PNS injury triggers a coordinated regenerative gene expression programme. However, the molecular link between retrograde signalling and the regulation of this gene expression programme that leads to the differential regenerative capacity remains elusive. Here we show through systematic epigenetic studies that the histone acetyltransferase p300/CBP-associated factor (PCAF) promotes acetylation of histone 3 Lys 9 at the promoters of established key regeneration-associated genes following a peripheral but not a central axonal injury. Furthermore, we find that extracellular signal-regulated kinase (ERK)-mediated retrograde signalling is required for PCAF-dependent regenerative gene reprogramming. Finally, PCAF is necessary for conditioning-dependent axonal regeneration and also singularly promotes regeneration after spinal cord injury. Thus, we find a specific epigenetic mechanism that regulates axonal regeneration of CNS axons, suggesting novel targets for clinical application.
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Lindner R, Puttagunta R, Di Giovanni S. Epigenetic regulation of axon outgrowth and regeneration in CNS injury: the first steps forward. Neurotherapeutics 2013; 10:771-81. [PMID: 23881454 PMCID: PMC3805867 DOI: 10.1007/s13311-013-0203-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Inadequate axonal sprouting and lack of regeneration limit functional recovery following neurologic injury, such as stroke, brain, and traumatic spinal cord injury. Recently, the enhancement of the neuronal regenerative program has led to promising improvements in axonal sprouting and regeneration in animal models of axonal injury. However, precise knowledge of the essential molecular determinants of this regenerative program remains elusive, thus limiting the choice of fully effective therapeutic strategies. Given that molecular regulation of axonal outgrowth and regeneration requires carefully orchestrated waves of gene expression, both temporally and spatially, epigenetic changes may be an ideal regulatory mechanism to address this unique need. While recent evidence suggests that epigenetic modifications could contribute to the regulation of axonal outgrowth and regeneration following axonal injury in models of stroke, and spinal cord and optic nerve injury, a number of unanswered questions remain. Such questions require systematic investigation of the epigenetic landscape between regenerative and non-regenerative conditions for the potential translation of this knowledge into regenerative strategies in human spinal and brain injury, as well as stroke.
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Affiliation(s)
- Ricco Lindner
- Laboratory for NeuroRegeneration and Repair, Center for Neurology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Otfried-Mueller Strasse 27, 72076 Tuebingen, Germany
| | - Radhika Puttagunta
- Laboratory for NeuroRegeneration and Repair, Center for Neurology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Otfried-Mueller Strasse 27, 72076 Tuebingen, Germany
| | - Simone Di Giovanni
- Laboratory for NeuroRegeneration and Repair, Center for Neurology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Otfried-Mueller Strasse 27, 72076 Tuebingen, Germany
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17
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Carter CJ. Susceptibility genes are enriched in those of the herpes simplex virus 1/host interactome in psychiatric and neurological disorders. Pathog Dis 2013; 69:240-61. [PMID: 23913659 DOI: 10.1111/2049-632x.12077] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 07/11/2013] [Accepted: 07/24/2013] [Indexed: 12/22/2022] Open
Abstract
Herpes simplex virus 1 (HSV-1) can promote beta-amyloid deposition and tau phosphorylation, demyelination or cognitive deficits relevant to Alzheimer's disease or multiple sclerosis and to many neuropsychiatric disorders with which it has been implicated. A seroprevalence much higher than disease incidence has called into question any primary causal role. However, as also the case with risk-promoting polymorphisms (also present in control populations), any causal effects are likely to be conditional. During its life cycle, the virus binds to many proteins and modifies the expression of multiple genes creating a host/pathogen interactome involving 1347 host genes. This data set is heavily enriched in the susceptibility genes for multiple sclerosis (P = 1.3E-99) > Alzheimer's disease > schizophrenia > Parkinsonism > depression > bipolar disorder > childhood obesity > chronic fatigue > autism > and anorexia (P = 0.047) but not attention deficit hyperactivity disorder, a relationship maintained for genome-wide association study data sets in multiple sclerosis and Alzheimer's disease. Overlapping susceptibility gene/interactome data sets disrupt signalling networks relevant to each disease, suggesting that disease susceptibility genes may filter the attentions of the pathogen towards particular pathways and pathologies. In this way, the same pathogen could contribute to multiple diseases in a gene-dependent manner and condition the risk-promoting effects of the genes whose function it disrupts.
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18
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Koriyama Y, Takagi Y, Chiba K, Yamazaki M, Sugitani K, Arai K, Suzuki H, Kato S. Requirement of retinoic acid receptor β for genipin derivative-induced optic nerve regeneration in adult rat retina. PLoS One 2013; 8:e71252. [PMID: 23940731 PMCID: PMC3735487 DOI: 10.1371/journal.pone.0071252] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 06/27/2013] [Indexed: 01/23/2023] Open
Abstract
Like other CNS neurons, mature retinal ganglion cells (RGCs) are unable to regenerate their axons after nerve injury due to a diminished intrinsic regenerative capacity. One of the reasons why they lose the capacity for axon regeneration seems to be associated with a dramatic shift in RGCs’ program of gene expression by epigenetic modulation. We recently reported that (1R)-isoPropyloxygenipin (IPRG001), a genipin derivative, has both neuroprotective and neurite outgrowth activities in murine RGC-5 retinal precursor cells. These effects were both mediated by nitric oxide (NO)/S-nitrosylation signaling. Neuritogenic activity was mediated by S-nitrosylation of histone deacetylase-2 (HDAC2), which subsequently induced retinoic acid receptor β (RARβ) expression via chromatin remodeling in vitro. RARβ plays important roles of neural growth and differentiation in development. However, the role of RARβ expression during adult rat optic nerve regeneration is not clear. In the present study, we extended this hypothesis to examine optic nerve regeneration by IPRG001 in adult rat RGCs in vivo. We found a correlation between RARβ expression and neurite outgrowth with age in the developing rat retina. Moreover, we found that IPRG001 significantly induced RARβ expression in adult rat RGCs through the S-nitrosylation of HDAC2 processing mechanism. Concomitant with RARβ expression, adult rat RGCs displayed a regenerative capacity for optic axons in vivo by IPRG001 treatment. These neuritogenic effects of IPRG001 were specifically suppressed by siRNA for RARβ. Thus, the dual neuroprotective and neuritogenic actions of genipin via S-nitrosylation might offer a powerful therapeutic tool for the treatment of RGC degenerative disorders.
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Affiliation(s)
- Yoshiki Koriyama
- Department of Molecular Neurobiology, Graduate School of Medicine, Kanazawa University, Kanazawa, Japan.
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19
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Structural basis for a molecular allosteric control mechanism of cofactor binding to nuclear receptors. Proc Natl Acad Sci U S A 2012; 109:E588-94. [PMID: 22355136 DOI: 10.1073/pnas.1118192109] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Transcription regulation by steroid hormones, vitamin derivatives, and metabolites is mediated by nuclear receptors (NRs), which play an important role in ligand-dependent gene expression and human health. NRs function as homodimers or heterodimers and are involved in a combinatorial, coordinated and sequentially orchestrated exchange between coregulators (corepressors, coactivators). The architecture of DNA-bound functional dimers positions the coregulators proteins. We previously demonstrated that retinoic acid (RAR-RXR) and vitamin D3 receptors (VDR-RXR) heterodimers recruit only one coactivator molecule asymmetrically without steric hindrance for the binding of a second cofactor. We now address the problem of homodimers for which the presence of two identical targets enhances the functional importance of the mode of binding. Using structural and biophysical methods and RAR as a model, we could dissect the molecular mechanism of coactivator recruitment to homodimers. Our study reveals an allosteric mechanism whereby binding of a coactivator promotes formation of nonsymmetrical RAR homodimers with a 21 stoichiometry. Ligand conformation and the cofactor binding site of the unbound receptor are affected through the dimer interface. A similar control mechanism is observed with estrogen receptor (ER) thus validating the negative cooperativity model for an established functional homodimer. Correlation with published data on other NRs confirms the general character of this regulatory pathway.
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Puttagunta R, Di Giovanni S. Retinoic acid signaling in axonal regeneration. Front Mol Neurosci 2012; 4:59. [PMID: 22287943 PMCID: PMC3249608 DOI: 10.3389/fnmol.2011.00059] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 12/22/2011] [Indexed: 01/28/2023] Open
Abstract
Following an acute central nervous system (CNS) injury, axonal regeneration and functional recovery are extremely limited. This is due to an extrinsic inhibitory growth environment and the lack of intrinsic growth competence. Retinoic acid (RA) signaling, essential in developmental dorsoventral patterning and specification of spinal motor neurons, has been shown through its receptor, the transcription factor RA receptor β2 (RARβ2), to induce axonal regeneration following spinal cord injury (SCI). Recently, it has been shown that in dorsal root ganglion neurons (DRGs), cAMP levels were greatly increased by lentiviral RARβ2 expression and contributed to neurite outgrowth. Moreover, RARβagonists, in cerebellar granule neurons (CGN) and in the brain in vivo, induced phosphoinositide 3-kinase dependent phosphorylation of AKT that was involved in RARβ-dependent neurite outgrowth. More recently, RA-RARβpathways were shown to directly transcriptionally repress a member of the inhibitory Nogo receptor (NgR) complex, Lingo-1, under an axonal growth inhibitory environment in vitro as well as following spinal injury in vivo. This perspective focuses on these newly discovered molecular mechanisms and future directions in the field.
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Affiliation(s)
- Radhika Puttagunta
- Laboratory for Neuroregeneration and Repair, Center for Neurology, Hertie Institute for Clinical Brain Research, University of Tuebingen Tuebingen, Germany
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Emerging roles for retinoids in regeneration and differentiation in normal and disease states. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:213-21. [PMID: 21855651 DOI: 10.1016/j.bbalip.2011.08.002] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 07/29/2011] [Accepted: 08/02/2011] [Indexed: 12/22/2022]
Abstract
The vitamin A (retinol) metabolite, all-trans retinoic acid (RA), is a signaling molecule that plays key roles in the development of the body plan and induces the differentiation of many types of cells. In this review the physiological and pathophysiological roles of retinoids (retinol and related metabolites) in mature animals are discussed. Both in the developing embryo and in the adult, RA signaling via combinatorial Hox gene expression is important for cell positional memory. The genes that require RA for the maturation/differentiation of T cells are only beginning to be cataloged, but it is clear that retinoids play a major role in expression of key genes in the immune system. An exciting, recent publication in regeneration research shows that ALDH1a2 (RALDH2), which is the rate-limiting enzyme in the production of RA from retinaldehyde, is highly induced shortly after amputation in the regenerating heart, adult fin, and larval fin in zebrafish. Thus, local generation of RA presumably plays a key role in fin formation during both embryogenesis and in fin regeneration. HIV transgenic mice and human patients with HIV-associated kidney disease exhibit a profound reduction in the level of RARβ protein in the glomeruli, and HIV transgenic mice show reduced retinol dehydrogenase levels, concomitant with a greater than 3-fold reduction in endogenous RA levels in the glomeruli. Levels of endogenous retinoids (those synthesized from retinol within cells) are altered in many different diseases in the lung, kidney, and central nervous system, contributing to pathophysiology. This article is part of a Special Issue entitled Retinoid and Lipid Metabolism.
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Short B. Retinoic acid keeps Lingo-1 quiet. J Biophys Biochem Cytol 2011. [PMCID: PMC3216341 DOI: 10.1083/jcb.1937iti1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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