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Jang YN, Jang H, Kim GH, Noh JE, Chang KA, Lee KJ. RAPGEF2 mediates oligomeric Aβ-induced synaptic loss and cognitive dysfunction in the 3xTg-AD mouse model of Alzheimer's disease. Neuropathol Appl Neurobiol 2021; 47:625-639. [PMID: 33345400 PMCID: PMC8359155 DOI: 10.1111/nan.12686] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 11/03/2020] [Accepted: 12/14/2020] [Indexed: 12/20/2022]
Abstract
AIMS Amyloid-β (Aβ) oligomers trigger synaptic degeneration that precedes plaque and tangle pathology. However, the signalling molecules that link Aβ oligomers to synaptic pathology remain unclear. Here, we addressed the potential role of RAPGEF2 as a novel signalling molecule in Aβ oligomer-induced synaptic and cognitive impairments in human-mutant amyloid precursor protein (APP) mouse models of Alzheimer's disease (AD). METHODS To investigate the role of RAPGEF2 in Aβ oligomer-induced synaptic and cognitive impairments, we utilised a combination of approaches including biochemistry, molecular cell biology, light and electron microscopy, behavioural tests with primary neuron cultures, multiple AD mouse models and post-mortem human AD brain tissue. RESULTS We found significantly elevated RAPGEF2 levels in the post-mortem human AD hippocampus. RAPGEF2 levels also increased in the transgenic AD mouse models, generating high levels of Aβ oligomers before exhibiting synaptic and cognitive impairment. RAPGEF2 upregulation activated the downstream effectors Rap2 and JNK. In cultured hippocampal neurons, oligomeric Aβ treatment increased the fluorescence intensity of RAPGEF2 and reduced the number of dendritic spines and the intensities of synaptic marker proteins, while silencing RAPGEF2 expression blocked Aβ oligomer-induced synapse loss. Additionally, the in vivo knockdown of RAPGEF2 expression in the AD hippocampus prevented cognitive deficits and the loss of excitatory synapses. CONCLUSIONS These findings demonstrate that the upregulation of RAPGEF2 levels mediates Aβ oligomer-induced synaptic and cognitive disturbances in the AD hippocampus. We propose that an early intervention regarding RAPGEF2 expression may have beneficial effects on early synaptic pathology and memory loss in AD.
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Affiliation(s)
- You-Na Jang
- Neural Circuits Research Group, Korea Brain Research Institute, Daegu, Republic of Korea
| | - HoChung Jang
- Neural Circuits Research Group, Korea Brain Research Institute, Daegu, Republic of Korea
| | - Gyu Hyun Kim
- Neural Circuits Research Group, Korea Brain Research Institute, Daegu, Republic of Korea
| | - Jeong-Eun Noh
- Neural Circuits Research Group, Korea Brain Research Institute, Daegu, Republic of Korea
| | - Keun-A Chang
- Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea
| | - Kea Joo Lee
- Neural Circuits Research Group, Korea Brain Research Institute, Daegu, Republic of Korea.,Department of Brain and Cognitive Sciences, DGIST, Daegu, Republic of Korea
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Kim Y, Jang YN, Kim JY, Kim N, Noh S, Kim H, Queenan BN, Bellmore R, Mun JY, Park H, Rah JC, Pak DTS, Lee KJ. Microtubule-associated protein 2 mediates induction of long-term potentiation in hippocampal neurons. FASEB J 2020; 34:6965-6983. [PMID: 32237183 DOI: 10.1096/fj.201902122rr] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 12/19/2022]
Abstract
Microtubule-associated protein (MAP) 2 has been perceived as a static cytoskeletal protein enriched in neuronal dendritic shafts. Emerging evidence indicates dynamic functions for various MAPs in activity-dependent synaptic plasticity. However, it is unclear how MAP2 is associated with synaptic plasticity mechanisms. Here, we demonstrate that specific silencing of high-molecular-weight MAP2 in vivo abolished induction of long-term potentiation (LTP) in the Schaffer collateral pathway of CA1 pyramidal neurons and in vitro blocked LTP-induced surface delivery of AMPA receptors and spine enlargement. In mature hippocampal neurons, we observed rapid translocation of a subpopulation of MAP2, present in dendritic shafts, to spines following LTP stimulation. Time-lapse confocal imaging showed that spine translocation of MAP2 was coupled with LTP-induced spine enlargement. Consistently, immunogold electron microscopy revealed that LTP stimulation of the Schaffer collateral pathway promoted MAP2 labeling in spine heads of CA1 neurons. This translocation depended on NMDA receptor activation and Ras-MAPK signaling. Furthermore, LTP stimulation led to an increase in surface-expressed AMPA receptors specifically in the neurons with MAP2 spine translocation. Altogether, this study indicates a novel role for MAP2 in LTP mechanisms and suggests that MAP2 participates in activity-dependent synaptic plasticity in mature hippocampal networks.
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Affiliation(s)
- Yoonju Kim
- Neural Circuits Research Group, Korea Basic Science Research Institute (KBRI), Daegu, Republic of Korea
| | - You-Na Jang
- Neural Circuits Research Group, Korea Basic Science Research Institute (KBRI), Daegu, Republic of Korea
| | - Ji-Young Kim
- Neurovascular Unit Research Group, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea
| | - Nari Kim
- Center for Cortical Processing, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea
| | - Seulgi Noh
- Neural Circuits Research Group, Korea Basic Science Research Institute (KBRI), Daegu, Republic of Korea
| | - Hyeyeon Kim
- Neurovascular Unit Research Group, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea
| | - Bridget N Queenan
- Department of Pharmacology and Physiology, Interdisciplinary Program of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | - Ryan Bellmore
- Department of Pharmacology and Physiology, Interdisciplinary Program of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | - Ji Young Mun
- Neural Circuits Research Group, Korea Basic Science Research Institute (KBRI), Daegu, Republic of Korea
| | - Hyungju Park
- Neurovascular Unit Research Group, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea.,Department of Brain and Cognitive Sciences, DGIST, Daegu, Republic of Korea
| | - Jong Cheol Rah
- Center for Cortical Processing, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea.,Department of Brain and Cognitive Sciences, DGIST, Daegu, Republic of Korea
| | - Daniel T S Pak
- Department of Pharmacology and Physiology, Interdisciplinary Program of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | - Kea Joo Lee
- Neural Circuits Research Group, Korea Basic Science Research Institute (KBRI), Daegu, Republic of Korea.,Center for Cortical Processing, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea.,Department of Brain and Cognitive Sciences, DGIST, Daegu, Republic of Korea
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Lee S, Jeon YM, Cha SJ, Kim S, Kwon Y, Jo M, Jang YN, Lee S, Kim J, Kim SR, Lee KJ, Lee SB, Kim K, Kim HJ. PTK2/FAK regulates UPS impairment via SQSTM1/p62 phosphorylation in TARDBP/TDP-43 proteinopathies. Autophagy 2019; 16:1396-1412. [PMID: 31690171 DOI: 10.1080/15548627.2019.1686729] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
TARDBP/TDP-43 (TAR DNA binding protein) proteinopathies are a common feature in a variety of neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTLD), and Alzheimer disease (AD). However, the molecular mechanisms underlying TARDBP-induced neurotoxicity are largely unknown. In this study, we demonstrated that TARDBP proteinopathies induce impairment in the ubiquitin proteasome system (UPS), as evidenced by an accumulation of ubiquitinated proteins and a reduction in proteasome activity in neuronal cells. Through kinase inhibitor screening, we identified PTK2/FAK (PTK2 protein tyrosine kinase 2) as a suppressor of neurotoxicity induced by UPS impairment. Importantly, PTK2 inhibition significantly reduced ubiquitin aggregates and attenuated TARDBP-induced cytotoxicity in a Drosophila model of TARDBP proteinopathies. We further identified that phosphorylation of SQSTM1/p62 (sequestosome 1) at S403 (p-SQSTM1 [S403]), a key component in the autophagic degradation of poly-ubiquitinated proteins, is increased upon TARDBP overexpression and is dependent on the activation of PTK2 in neuronal cells. Moreover, expressing a non-phosphorylated form of SQSTM1 (SQSTM1S403A) significantly repressed the accumulation of insoluble poly-ubiquitinated proteins and neurotoxicity induced by TARDBP overexpression in neuronal cells. In addition, TBK1 (TANK binding kinase 1), a kinase that phosphorylates S403 of SQSTM1, was found to be involved in the PTK2-mediated phosphorylation of SQSTM1. Taken together, our data suggest that the PTK2-TBK1-SQSTM1 axis plays a critical role in the pathogenesis of TARDBP by regulating neurotoxicity induced by UPS impairment. Therefore, targeting the PTK2-TBK1-SQSTM1 axis may represent a novel therapeutic intervention for neurodegenerative diseases with TARDBP proteinopathies.Abbreviations: ALP: macroautophagy/autophagy lysosomal pathway; ALS: amyotrophic lateral sclerosis; ATXN2: ataxin 2; BafA1: bafilomycin A1; cCASP3: cleaved caspase 3; CSNK2: casein kinase 2; FTLD: frontotemporal lobar degeneration; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; OPTN: optineurin; PTK2/FAK: PTK2 protein tyrosine kinase 2; SQSTM1/p62: sequestosome 1; TARDBP/TDP-43: TAR DNA binding protein; TBK1: TANK binding kinase 1; ULK1: unc-51 like autophagy activating kinase 1; UPS: ubiquitin-proteasome system.
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Affiliation(s)
- Shinrye Lee
- Dementia Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea
| | - Yu-Mi Jeon
- Dementia Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea
| | - Sun Joo Cha
- Soonchunhyang Institute of Medi-bio Science, Soonchunhyang University , Cheonan, South Korea
| | - Seyeon Kim
- Dementia Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea.,Department of Brain & Cognitive Sciences, DGIST , Daegu, South Korea
| | - Younghwi Kwon
- Dementia Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea.,Department of Brain & Cognitive Sciences, DGIST , Daegu, South Korea
| | - Myungjin Jo
- Dementia Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea
| | - You-Na Jang
- Neural circuits Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea
| | - Seongsoo Lee
- Gwangju Center, Korea Basic Science Institute (KBSI) , Gwangju, South Korea
| | - Jaekwang Kim
- Dementia Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea
| | - Sang Ryong Kim
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Institute of Life Science & Biotechnology, Kyungpook National University , Daegu, South Korea.,Brain Science and Engineering Institute, Kyungpook National University , Daegu, South Korea
| | - Kea Joo Lee
- Neural circuits Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea
| | - Sung Bae Lee
- Department of Brain & Cognitive Sciences, DGIST , Daegu, South Korea
| | - Kiyoung Kim
- Soonchunhyang Institute of Medi-bio Science, Soonchunhyang University , Cheonan, South Korea.,Department of Medical Biotechnology, Soonchunhyang University , Asan, South Korea
| | - Hyung-Jun Kim
- Dementia Research Group, Korea Brain Research Institute (KBRI) , Daegu, South Korea
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Choi MG, Kim MJ, Kim DG, Yu R, Jang YN, Oh WJ. Sequestration of synaptic proteins by alpha-synuclein aggregates leading to neurotoxicity is inhibited by small peptide. PLoS One 2018; 13:e0195339. [PMID: 29608598 PMCID: PMC5880409 DOI: 10.1371/journal.pone.0195339] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/20/2018] [Indexed: 12/15/2022] Open
Abstract
α-Synuclein (α-syn) is a major component of Lewy bodies found in synucleinopathies including Parkinson’s disease (PD) and Dementia with Lewy Bodies (DLB). Under the pathological conditions, α-syn tends to generate a diverse form of aggregates showing toxicity to neuronal cells and able to transmit across cells. However, mechanisms by which α-syn aggregates affect cytotoxicity in neurons have not been fully elucidated. Here we report that α-syn aggregates preferentially sequester specific synaptic proteins such as vesicle-associated membrane protein 2 (VAMP2) and synaptosomal-associated protein 25 (SNAP25) through direct binding which is resistant to SDS. The sequestration effect of α-syn aggregates was shown in a cell-free system, cultured primary neurons, and PD mouse model. Furthermore, we identified a specific blocking peptide derived from VAMP2 which partially inhibited the sequestration by α-syn aggregates and contributed to reduced neurotoxicity. These results provide a mechanism of neurotoxicity mediated by α-syn aggregates and suggest that the blocking peptide interfering with the pathological role of α-syn aggregates could be useful for designing a potential therapeutic drug for the treatment of PD.
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Affiliation(s)
- Mal-Gi Choi
- Department of Structure and Function of Neural Network, Korea Brain Research Institute, Daegu, South Korea
- * E-mail: (WJO); (MGC)
| | - Mi Jin Kim
- Department of Structure and Function of Neural Network, Korea Brain Research Institute, Daegu, South Korea
| | - Do-Geun Kim
- Department of Structure and Function of Neural Network, Korea Brain Research Institute, Daegu, South Korea
| | - Ri Yu
- Department of Structure and Function of Neural Network, Korea Brain Research Institute, Daegu, South Korea
| | - You-Na Jang
- Department of Structure and Function of Neural Network, Korea Brain Research Institute, Daegu, South Korea
| | - Won-Jong Oh
- Department of Structure and Function of Neural Network, Korea Brain Research Institute, Daegu, South Korea
- * E-mail: (WJO); (MGC)
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Abstract
Myogenic differentiation plays an important role in muscle regeneration and is regulated by two transcription factor families, MRFs and MEF2, which induce differentiation of myoblasts through expression of the muscle-specific gene, myogenin. In addition, many intracellular signaling pathways are also involved in myogenic differentiation, including p38 MAPK, ERK/MAPK and PI3K/AKT. The JAK-STAT pathway is activated by various cytokines and positively or negatively regulates the differentiation of myoblasts. JAK1 plays a notable role in proliferation; whereas, JAK2 and JAK3 function mainly in differentiation. The STATs, molecules downstream of JAK, regulate myogenesis. With JAK1, STAT1 promotes proliferation, while STAT3 has a dual effect on proliferation and differentiation. The JAK-STAT negative regulator, SOCS, is also associated with myogenesis; although, its role is controversial. In this review, we will discuss the role of the JAK-STAT pathway on myogenic differentiation.
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Affiliation(s)
- You-Na Jang
- Department of Physiology; Chronic Inflammatory Disease Research Center; Ajou University School of Medicine; Suwon, Korea
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Abstract
Skeletal muscle differentiation is regulated by transcription factors, including members of the myogenic regulatory factor (MRF) family and many signaling pathways. The JAK1 and JAK2 pathways are known to each have different effects on myoblast proliferation and differentiation; however, the role of JAK3 in myoblast differentiation remains unclear. In this study, we investigated the effect of JAK3 inhibition on myogenic differentiation in the C2C12 mouse myoblast cell line. During myogenic differentiation, treatment with the JAK3 inhibitor WHIp154 significantly increased the number of MHC-positive multinucleated myotubes and the expressions of myosin heavy chain (MHC), myogenin (MGN), MyoD, and myogenic enhancer factor 2 (MEF2). Knockdown of the JAK3 gene using siJAK3 also significantly increased MHC, MGN and MyoD mRNA expressions as well as insulin-like growth factor-II (IGF-II) gene expression. During differentiation, JAK3 was initially activated and later decreased. Differentiation decreased STAT1, which was further decreased by WHIp154. In contrast, STAT3 gradually was elevated during differentiation, and was increased by JAK3 inhibition. Moreover, we found that up-regulation of AKT activity and down-regulation of ERK activity cooperated to accelerate myogenic differentiation. Taken together, these data indicate that JAK3 inhibition potently facilitates myoblast differentiation through antagonistic STAT1/STAT3 activities. Additionally, JAK3 inhibition induced precocious differentiation and played important roles for terminal differentiation, including fusion, which is involved with regulation of AKT and ERK pathways.
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Affiliation(s)
- You-Na Jang
- Department of Physiology, Ajou University School of Medicine, Suwon, Republic of Korea
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