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Ka M, Kim WY. ANKRD11 associated with intellectual disability and autism regulates dendrite differentiation via the BDNF/TrkB signaling pathway. Neurobiol Dis 2017; 111:138-152. [PMID: 29274743 DOI: 10.1016/j.nbd.2017.12.008] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/29/2017] [Accepted: 12/19/2017] [Indexed: 01/29/2023] Open
Abstract
Haploinsufficiency of ANKRD11 due to deletion or truncation mutations causes KBG syndrome, a rare genetic disorder characterized by intellectual disability, autism spectrum disorder, and craniofacial abnormalities. However, little is known about the neurobiological role of ANKRD11 during brain development. Here we show that ANKRD11 regulates pyramidal neuron migration and dendritic differentiation in the developing mouse cerebral cortex. Using an in utero manipulation approach, we found that Ankrd11 knockdown delayed radial migration of cortical neurons. ANKRD11-deficient neurons displayed markedly reduced dendrite growth and branching as well as abnormal dendritic spine morphology. Ankrd11 knockdown suppressed acetylation of epigenetic molecules such as p53 and Histone H3. Furthermore, the mRNA levels of Trkb, Bdnf, and neurite growth-related genes were downregulated in ANKRD11-deficient cortical neurons. The Trkb promoter region was largely devoid of acetylated Histone H3 and p53, and was instead occupied with MeCP2 and DNMT1. Overexpression of TrkB rescued abnormal dendrite growth in these cells. Our findings demonstrate a novel role for ANKRD11 in neuron differentiation during brain development and suggest an epigenetic modification as a potential key molecular feature underlying KBG syndrome.
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Affiliation(s)
- Minhan Ka
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, NE 68198, United States
| | - Woo-Yang Kim
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, NE 68198, United States.
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Ka M, Smith AL, Kim WY. MTOR controls genesis and autophagy of GABAergic interneurons during brain development. Autophagy 2017; 13:1348-1363. [PMID: 28598226 DOI: 10.1080/15548627.2017.1327927] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Interneuron progenitors in the ganglionic eminence of the ventral telencephalon generate most cortical interneurons during brain development. However, the regulatory mechanism of interneuron progenitors remains poorly understood. Here, we show that MTOR (mechanistic target of rapamycin [serine/threonine kinase]) regulates proliferation and macroautophagy/autophagy of interneuron progenitors in the developing ventral telencephalon. To investigate the role of MTOR in interneuron progenitors, we conditionally deleted the Mtor gene in mouse interneuron progenitors and their progeny by using Tg(mI56i-cre,EGFP)1Kc/Dlx5/6-Cre-IRES-EGFP and Nkx2-1-Cre drivers. We found that Mtor deletion markedly reduced the number of interneurons in the cerebral cortex. However, relative positioning of cortical interneurons was normal, suggesting that disruption of progenitor self-renewal caused the decreased number of cortical interneurons in the Mtor-deleted brain. Indeed, Mtor-deleted interneuron progenitors showed abnormal proliferation and cell cycle progression. Additionally, we detected a significant activation of autophagy in Mtor-deleted brain. Our findings suggest that MTOR plays a critical role in the regulation of cortical interneuron number and autophagy in the developing brain.
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Affiliation(s)
- Minhan Ka
- a Department of Developmental Neuroscience , Munroe-Meyer Institute, University of Nebraska Medical Center , Omaha , NE , USA
| | - Amanda L Smith
- a Department of Developmental Neuroscience , Munroe-Meyer Institute, University of Nebraska Medical Center , Omaha , NE , USA
| | - Woo-Yang Kim
- a Department of Developmental Neuroscience , Munroe-Meyer Institute, University of Nebraska Medical Center , Omaha , NE , USA
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Ka M, Kook YH, Liao K, Buch S, Kim WY. Transactivation of TrkB by Sigma-1 receptor mediates cocaine-induced changes in dendritic spine density and morphology in hippocampal and cortical neurons. Cell Death Dis 2016; 7:e2414. [PMID: 27735948 PMCID: PMC5133986 DOI: 10.1038/cddis.2016.319] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 08/31/2016] [Accepted: 09/09/2016] [Indexed: 01/02/2023]
Abstract
Cocaine is a highly addictive narcotic associated with dendritic spine plasticity in the striatum. However, it remains elusive whether cocaine modifies spines in a cell type-specific or region-specific manner or whether it alters different types of synapses in the brain. In addition, there is a paucity of data on the regulatory mechanism(s) involved in cocaine-induced modification of spine density. In the current study, we report that cocaine exposure differentially alters spine density, spine morphology, and the types of synapses in hippocampal and cortical neurons. Cocaine exposure in the hippocampus resulted in increased spine density, but had no significant effect on cortical neurons. Although cocaine exposure altered spine morphology in both cell types, the patterns of spine morphology were distinct for each cell type. Furthermore, we observed that cocaine selectively affects the density of excitatory synapses. Intriguingly, in hippocampal neurons cocaine-mediated effects on spine density and morphology involved sigma-1 receptor (Sig-1 R) and its downstream TrkB signaling, which were not the case in cortical neurons. Furthermore, pharmacological inhibition of Sig-1 R prevented cocaine-induced TrkB activation in hippocampal neurons. Our findings reveal a novel mechanism by which cocaine induces selective changes in spine morphology, spine density, and synapse formation, and could provide insights into the cellular basis for the cognitive impairment observed in cocaine addicts.
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Affiliation(s)
- Minhan Ka
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Yeon-Hee Kook
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Ke Liao
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Woo-Yang Kim
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, NE 68198, USA
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Ku JM, Park K, Lee JH, Cho KJ, Nam YJ, Jeong DY, Kim YH, Kwon S, Park JY, Yang J, Nam TG, Yoon SH, Ahn S, Choi Y. Discovery, Optimization, and Biological Evaluation of Sulfonamidoacetamides as an Inducer of Axon Regeneration. J Med Chem 2016; 59:4676-87. [PMID: 27007292 DOI: 10.1021/acs.jmedchem.6b00015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Axon regeneration after injury in the central nervous system is hampered in part because if an age-dependent decline in the intrinsic axon growth potential, and one of the strategies to stimulate axon growth in injured neurons involves pharmacological manipulation of implicated signaling pathways. Here we report phenotypic cell-based screen of chemical libraries and structure-activity-guided optimization that resulted in the identification of compound 7p which promotes neurite outgrowth of cultured primary neurons derived from the hippocampus, cerebral cortex, and retina. In an animal model of optic nerve injury, compound 7p was shown to induce growth of GAP-43 positive axons, indicating that the in vitro neurite outgrowth activity of compound 7p translates into stimulation of axon regeneration in vivo. Further optimization of compound 7p and elucidation of the mechanisms by which it elicits axon regeneration in vivo will provide a rational basis for future efforts to enhance treatment strategies.
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Affiliation(s)
- Jin-Mo Ku
- Bio-Center, Gyeonggi Institute of Science and Technology Promotion , 147 Gwanggyo-ro, Suwon, Korea 16229
| | - Kyuhee Park
- Bio-Center, Gyeonggi Institute of Science and Technology Promotion , 147 Gwanggyo-ro, Suwon, Korea 16229
| | - Jung Hun Lee
- Bio-Center, Gyeonggi Institute of Science and Technology Promotion , 147 Gwanggyo-ro, Suwon, Korea 16229
| | | | - Yeon-Ju Nam
- Bio-Center, Gyeonggi Institute of Science and Technology Promotion , 147 Gwanggyo-ro, Suwon, Korea 16229
| | - Dae-Youn Jeong
- Bio-Center, Gyeonggi Institute of Science and Technology Promotion , 147 Gwanggyo-ro, Suwon, Korea 16229
| | | | - SoonJung Kwon
- Department of Applied Chemistry, Ajou University , 206 Worldcup-ro, Suwon, Korea 16499
| | - Ju-Young Park
- Department of Applied Chemistry, Ajou University , 206 Worldcup-ro, Suwon, Korea 16499
| | - Jungeun Yang
- Bio-Center, Gyeonggi Institute of Science and Technology Promotion , 147 Gwanggyo-ro, Suwon, Korea 16229
| | - Tae-Gyu Nam
- Department of Pharmacy, Hanyang University , 55 Hanyangdaehak-ro, Ansan, Korea 15588
| | - Sung-Hwa Yoon
- Department of Applied Chemistry, Ajou University , 206 Worldcup-ro, Suwon, Korea 16499
| | | | - Yongmun Choi
- Bio-Center, Gyeonggi Institute of Science and Technology Promotion , 147 Gwanggyo-ro, Suwon, Korea 16229
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Huang SY, Sung CS, Chen WF, Chen CH, Feng CW, Yang SN, Hung HC, Chen NF, Lin PR, Chen SC, Wang HMD, Chu TH, Tai MH, Wen ZH. Involvement of phosphatase and tensin homolog deleted from chromosome 10 in rodent model of neuropathic pain. J Neuroinflammation 2015; 12:59. [PMID: 25889774 PMCID: PMC4386079 DOI: 10.1186/s12974-015-0280-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 03/07/2015] [Indexed: 12/30/2022] Open
Abstract
Background Many cancer research studies have extensively examined the phosphatase and tensin homolog deleted from chromosome 10 (PTEN) pathway. There are only few reports that suggest that PTEN might affect pain; however, there is still a lack of evidence to show the role of PTEN for modulating pain. Here, we report a role for PTEN in a rodent model of neuropathic pain. Results We found that chronic constriction injury (CCI) surgery in rats could elicit downregulation of spinal PTEN as well as upregulation of phosphorylated PTEN (phospho-PTEN) and phosphorylated mammalian target of rapamycin (phospho-mTOR). After examining such changes in endogenous PTEN in neuropathic rats, we explored the effects of modulating the spinal PTEN pathway on nociceptive behaviors. The normal rats exhibited mechanical allodynia after intrathecal (i.t.) injection of adenovirus-mediated PTEN antisense oligonucleotide (Ad-antisense PTEN). These data indicate the importance of downregulation of spinal PTEN for nociception. Moreover, upregulation of spinal PTEN by i.t. adenovirus-mediated PTEN (Ad-PTEN) significantly prevented CCI-induced development of nociceptive sensitization, thermal hyperalgesia, mechanical allodynia, cold allodynia, and weight-bearing deficits in neuropathic rats. Furthermore, upregulation of spinal PTEN by i.t. Ad-PTEN significantly attenuated CCI-induced microglia and astrocyte activation, upregulation of tumor necrosis factor-α (TNF-α) and phospho-mTOR, and downregulation of PTEN in neuropathic rats 14 days post injury. Conclusions These findings demonstrate that PTEN plays a key, beneficial role in a rodent model of neuropathic pain.
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Affiliation(s)
- Shi-Ying Huang
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan. .,Center for Neuroscience, National Sun Yat-sen University, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan.
| | - Chun-Sung Sung
- Department of Anesthesiology, Taipei Veterans General Hospital, No. 201, Section 2, Shipai Road, Taipei, 11217, Taiwan. .,School of Medicine, National Yang-Ming University, No. 155, Section 2, Linong Street, Taipei, 11221, Taiwan.
| | - Wu-Fu Chen
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan. .,Department of Neurosurgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, No. 123, DAPI Road, Kaohsiung, 83301, Taiwan. .,Department of Neurosurgery, Xiamen Chang Gung Memorial Hospital, No. 123, Xiafei Road, Fujian, 361026, China.
| | - Chun-Hong Chen
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan. .,Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University and Academia Sinica, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan.
| | - Chien-Wei Feng
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan. .,Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University and Academia Sinica, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan.
| | - San-Nan Yang
- School of Medicine, College of Medicine and Department of Pediatrics, E-DA Hospital, I-Shou University, No. 1, Yida Road, Kaohsiung, 82445, Taiwan.
| | - Han-Chun Hung
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan. .,Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University and Academia Sinica, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan.
| | - Nan-Fu Chen
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan. .,Division of Neurosurgery, Department of Surgery, Kaohsiung Armed Forces General Hospital, No. 2, Zhongzheng 1st Road, Kaohsiung, 80284, Taiwan.
| | - Pey-Ru Lin
- Institute of Biomedical Sciences, National Sun Yat-sen University, #70 Lienhai Road, Kaohsiung, 80424, Taiwan.
| | - San-Cher Chen
- Center for Neuroscience, National Sun Yat-sen University, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan. .,Institute of Biomedical Sciences, National Sun Yat-sen University, #70 Lienhai Road, Kaohsiung, 80424, Taiwan.
| | - Hui-Min David Wang
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan. .,Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, No. 100, Shiquan 1st Road, Kaohsiung, 80708, Taiwan. .,Graduate Institute of Natural Products, Kaohsiung Medical University, No. 100, Shiquan 1st Road, Kaohsiung, 80708, Taiwan. .,Center for Stem Cell Research, Kaohsiung Medical University, No. 100, Shiquan 1st Road, Kaohsiung, 80708, Taiwan.
| | - Tian-Huei Chu
- Institute of Biomedical Sciences, National Sun Yat-sen University, #70 Lienhai Road, Kaohsiung, 80424, Taiwan.
| | - Ming-Hong Tai
- Center for Neuroscience, National Sun Yat-sen University, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan. .,Institute of Biomedical Sciences, National Sun Yat-sen University, #70 Lienhai Road, Kaohsiung, 80424, Taiwan. .,Department of Biological Sciences, National Sun Yat-sen University, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan.
| | - Zhi-Hong Wen
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan. .,Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University and Academia Sinica, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan. .,Marine Biomedical Laboratory and Center for Translational Biopharmaceuticals, Department of Marine Biotechnology and Resources, National Sun Yat-sen University, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan.
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Dibutyryl cyclic AMP inhibits the progression of experimental autoimmune encephalomyelitis and potentiates recruitment of endogenous neural stem cells. J Mol Neurosci 2013; 51:298-306. [PMID: 23335001 DOI: 10.1007/s12031-013-9959-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 01/10/2013] [Indexed: 12/15/2022]
Abstract
Multiple sclerosis is a chronic inflammatory demyelinating disease of the central nervous system. Cyclic AMP and its analogs enhance regeneration of adult mammalian central nervous system (CNS). Endogenous neural stem cells (NSCs) play a pivotal role in CNS regeneration, producing new neuron and glial cells. Here, we examined the effect of dibutyryl cyclic AMP (dbcAMP) on experimental autoimmune encephalomyelitis (EAE) symptoms, endogenous remyelination, and recruitment of NSCs. EAE was induced by immunizing mice using myelin oligodendrocyte glycoprotein peptide and pertussis toxin. Proliferative cells within CNS were labeled using repetitive systemic injections of 5-bromo-2-deoxyuridine (BrdU) before EAE induction. Myelin staining was performed using Luxol fast blue. The number of nestin(+) and BrdU(+) cells in subventricular zone (SVZ) and olfactory bulb (OB) was evaluated using immunohistochemistry. dbcAMP suppressed EAE progression and decreased the extent of demyelinated plaques in the lumbar spinal cord. EAE induction reduced the number of proliferative cells in SVZ and increased their population in OB. EAE also increased the number of nestin(+) cells in OB. We also found that dbcAMP increased the recruitment of NSCs into the OB and brain parenchyma of EAE mice. Our results suggest dbcAMP as a potential therapy for inducing myelin repair in the context of demyelinating diseases like multiple sclerosis. Its positive effect seems to be mediated, at least partially, by endogenous neural stem cells and their increased recruitment.
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Zheng J, Feng X, Hou L, Cui Y, Zhu L, Ma J, Xia Z, Zhou W, Chen H. Latanoprost promotes neurite outgrowth in differentiated RGC-5 cells via the PI3K-Akt-mTOR signaling pathway. Cell Mol Neurobiol 2011; 31:597-604. [PMID: 21279434 PMCID: PMC11498634 DOI: 10.1007/s10571-011-9653-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Accepted: 01/12/2011] [Indexed: 12/21/2022]
Abstract
Latanoprost, a synthetic derivative of the natural prostaglandin F(2a) (PGF(2a)), is a powerful antiglaucoma agent with ocular hypotensive and neuroprotective effects. However, the neuroregenerative effect and signaling pathway of latanoprost in retinal ganglion cells (RGCs) are still unknown. The purpose of this study is to investigate the regenerative effect of latanoprost in differentiated RGC-5 cells and its underlying mechanisms. Cell viability was determined by Cell Counting Kit-8 (CCK-8) assay and neurite length was examined by ArrayScan HCS Reader and Neurite outgrowth BioApplication. Expressions of Akt phosphorylation (p-Akt) and mammalian target of rapamycin phosphorylation (p-mTOR) were investigated by Western blot analysis. The results indicated that 0.1 μM latanoprost (at a clinically therapeutic concentration) significantly increased cell viability as compared with control. Meanwhile, 0.1 μM latanoprost resulted in the obvious promotion of neurite outgrowth similar to ciliary neurotrophic factor (CNTF) and simultaneously increased the levels of p-Akt and p-mTOR expression. The effects of latanoprost were blocked by the Prostaglandin F receptor (FP receptor) inhibitor AL8810, the phosphoinositide 3-kinase (PI3K) inhibitor LY294002 and the mTOR inhibitor rapamycin. This study presents novel in vitro evidence that latanoprost could promote neurite outgrowth through an FP receptor-mediated modulation of the PI3K-Akt-mTOR signaling pathway. This finding may provide insight into a better understanding of a new mechanism of latanoprost for glaucoma therapy and into the physiological-modulating activities of prostaglandins.
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Affiliation(s)
- Jun Zheng
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025 China
| | - Xuemei Feng
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025 China
| | - Lina Hou
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025 China
| | - Yongyao Cui
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025 China
| | - Liang Zhu
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025 China
| | - Jian Ma
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025 China
| | - Zheng Xia
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025 China
| | - Wei Zhou
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025 China
| | - Hongzhuan Chen
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025 China
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Ziegler L, Segal-Ruder Y, Coppola G, Reis A, Geschwind D, Fainzilber M, Goldstein RS. A human neuron injury model for molecular studies of axonal regeneration. Exp Neurol 2010; 223:119-27. [DOI: 10.1016/j.expneurol.2009.09.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 09/24/2009] [Accepted: 09/25/2009] [Indexed: 11/30/2022]
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Seira O, Gavín R, Gil V, Llorens F, Rangel A, Soriano E, del Río JA. Neurites regrowth of cortical neurons by GSK3beta inhibition independently of Nogo receptor 1. J Neurochem 2010; 113:1644-58. [PMID: 20374426 DOI: 10.1111/j.1471-4159.2010.06726.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Lesioned axons do not regenerate in the adult mammalian CNS, owing to the over-expression of inhibitory molecules such as myelin-derived proteins or chondroitin sulphate proteoglycans. In order to overcome axon inhibition, strategies based on extrinsic and intrinsic treatments have been developed. For myelin-associated inhibition, blockage with NEP1-40, receptor bodies or IN-1 antibodies has been used. In addition, endogenous blockage of cell signalling mechanisms induced by myelin-associated proteins is a potential tool for overcoming axon inhibitory signals. We examined the participation of glycogen synthase kinase 3beta (GSK3beta) and extracellular-related kinase (ERK) 1/2 in axon regeneration failure in lesioned cortical neurons. We also investigated whether pharmacological blockage of GSK3beta and ERK1/2 activities facilitates regeneration after myelin-directed inhibition in two models: (i) cerebellar granule cells and (ii) lesioned entorhino-hippocampal pathway in slice cultures, and whether the regenerative effects are mediated by Nogo Receptor 1 (NgR1). We demonstrate that, in contrast to ERK1/2 inhibition, the pharmacological treatment of GSK3beta inhibition strongly facilitated regrowth of cerebellar granule neurons over myelin independently of NgR1. Finally, these regenerative effects were corroborated in the lesioned entorhino-hippocampal pathway in NgR1-/- mutant mice. These results provide new findings for the development of new assays and strategies to enhance axon regeneration in injured cortical connections.
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Affiliation(s)
- Oscar Seira
- Molecular and Cellular Neurobiotechnology, Institute for Bioengineering of Catalonia, Barcelona, Spain
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10
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Kuang X, Shen J, Wong PK, Yan M. Deregulation of mTOR signaling is involved in thymic lymphoma development in Atm−/− mice. Biochem Biophys Res Commun 2009; 383:368-72. [DOI: 10.1016/j.bbrc.2009.04.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Accepted: 04/03/2009] [Indexed: 12/18/2022]
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11
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Munderloh C, Solis GP, Bodrikov V, Jaeger FA, Wiechers M, Málaga-Trillo E, Stuermer CAO. Reggies/flotillins regulate retinal axon regeneration in the zebrafish optic nerve and differentiation of hippocampal and N2a neurons. J Neurosci 2009; 29:6607-15. [PMID: 19458231 PMCID: PMC6665911 DOI: 10.1523/jneurosci.0870-09.2009] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Revised: 04/15/2009] [Accepted: 04/20/2009] [Indexed: 11/21/2022] Open
Abstract
The reggies/flotillins--proteins upregulated during axon regeneration in retinal ganglion cells (RGCs)--are scaffolding proteins of microdomains and involved in neuronal differentiation. Here, we show that reggies regulate axon regeneration in zebrafish (ZF) after optic nerve section (ONS) in vivo as well as axon/neurite extension in hippocampal and N2a neurons in vitro through signal transduction molecules modulating actin dynamics. ZF reggie-1a, -2a, and -2b downregulation by reggie-specific morpholino (Mo) antisense oligonucleotides directly after ONS significantly reduced ZF RGC axon regeneration: RGC axons from reggie Mo retinas were markedly reduced. Moreover, the number of axon-regenerating RGCs, identified by insertion of A488-coupled dextran, decreased by 69% in retinas 7 d after Mo application. At 10 and 14 d, RGCs decreased by 53 and 33%, respectively, in correlation with the gradual inactivation of the Mos. siRNA-mediated knockdown of reggie-1 and -2 inhibited the differentiation and axon/neurite extension in hippocampal and N2a neurons. N2a cells had significantly shorter filopodia, more cells had lamellipodia and fewer neurites, defects which were rescued by a reggie-1 construct without siRNA-binding sites. Furthermore, reggie knockdown strongly perturbed the balanced activation of the Rho family GTPases Rac1, RhoA, and cdc42, influenced the phosphorylation of cortactin and cofilin, the formation of the N-WASP, cortactin and Arp3 complex, and affected p38, Ras, ERK1/2 (extracellular signal-regulated kinases 1 and 2), and focal adhesion kinase activation. Thus, as suggested by their prominent re-expression after lesion, the reggies represent neuron-intrinsic factors for axon outgrowth and regeneration, being crucial for the coordinated assembly of signaling complexes regulating cytoskeletal remodeling.
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Affiliation(s)
| | - Gonzalo P. Solis
- Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
| | - Vsevolod Bodrikov
- Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
| | | | - Marianne Wiechers
- Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
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Abstract
Autism spectrum disorder is 90% genetic but responds dramatically to intensive early training. Recent reports indicate many of the genetic variations associated with ASD involve activity-dependent regulation in the brain, or synapse development that depends on postnatal learning and experience. Intensive training can apparently overcome the effects of these genetic variations, but this should be started as early as 12 months of age for best results. The proposed reason is the decline in brain plasticity after about 6 years. In addition, the problems caused by ASD may cascade on a trajectory toward full expression of the disorder, making it important to interrupt this sequence before it builds. The possibility of reopening plasticity to increase effectiveness of intervention later in life is discussed.
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Abstract
The cell body of a lesioned neuron must receive accurate and timely information on the site and extent of axonal damage, in order to mount an appropriate response. Specific mechanisms must therefore exist to transmit such information along the length of the axon from the lesion site to the cell body. Three distinct types of signals have been postulated to underlie this process, starting with injury-induced discharge of axon potentials, and continuing with two distinct types of retrogradely transported macromolecular signals. The latter includes, on the one hand, an interruption of the normal supply of retrogradely transported trophic factors from the target, and, on the other hand, activated proteins originating from the injury site. This chapter reviews the progress on understanding the different mechanistic aspects of the axonal response to injury, and how the information is conveyed from the injury site to the cell body to initiate regeneration.
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Affiliation(s)
- Keren Ben-Yaakov
- Department of Biological Chemistry, Weizmann Institute of Science, 76100 Rehovot, Israel
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