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Yang Y, Song R, Gao Y, Yu H, Wang S. Regulatory mechanisms and therapeutic potential of JAB1 in neurological development and disorders. Mol Med 2023; 29:80. [PMID: 37365502 DOI: 10.1186/s10020-023-00675-w] [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: 04/10/2023] [Accepted: 05/30/2023] [Indexed: 06/28/2023] Open
Abstract
c-Jun activation domain binding protein-1 (JAB1) is a multifunctional regulator that plays vital roles in diverse cellular processes. It regulates AP-1 transcriptional activity and also acts as the fifth component of the COP9 signalosome complex. While JAB1 is considered an oncoprotein that triggers tumor development, recent studies have shown that it also functions in neurological development and disorders. In this review, we summarize the general features of the JAB1 gene and protein, and present recent updates on the regulation of JAB1 expression. Moreover, we also highlight the functional roles and regulatory mechanisms of JAB1 in neurodevelopmental processes such as neuronal differentiation, synaptic morphogenesis, myelination, and hair cell development and in the pathogenesis of some neurological disorders such as Alzheimer's disease, multiple sclerosis, neuropathic pain, and peripheral nerve injury. Furthermore, current challenges and prospects are discussed, including updates on drug development targeting JAB1.
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Affiliation(s)
- Yu Yang
- Department of Psychiatry, Jining Medical University, Jianshe South Road No. 45, Jining, Shandong, China
- Shandong Collaborative Innovation Center for Diagnosis, Treatment and Behavioral Interventions of Mental Disorders, Jining Medical University, Jining, Shandong, China
| | - Ruying Song
- Department of Psychiatry, Jining Medical University, Jianshe South Road No. 45, Jining, Shandong, China
- Shandong Collaborative Innovation Center for Diagnosis, Treatment and Behavioral Interventions of Mental Disorders, Jining Medical University, Jining, Shandong, China
| | - Yiming Gao
- Department of Psychiatry, Jining Medical University, Jianshe South Road No. 45, Jining, Shandong, China
- Shandong Collaborative Innovation Center for Diagnosis, Treatment and Behavioral Interventions of Mental Disorders, Jining Medical University, Jining, Shandong, China
| | - Hao Yu
- Department of Psychiatry, Jining Medical University, Jianshe South Road No. 45, Jining, Shandong, China.
- Shandong Collaborative Innovation Center for Diagnosis, Treatment and Behavioral Interventions of Mental Disorders, Jining Medical University, Jining, Shandong, China.
| | - Shuai Wang
- Department of Psychiatry, Jining Medical University, Jianshe South Road No. 45, Jining, Shandong, China.
- Shandong Collaborative Innovation Center for Diagnosis, Treatment and Behavioral Interventions of Mental Disorders, Jining Medical University, Jining, Shandong, China.
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Structural and Functional Insights into GID/CTLH E3 Ligase Complexes. Int J Mol Sci 2022; 23:ijms23115863. [PMID: 35682545 PMCID: PMC9180843 DOI: 10.3390/ijms23115863] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/18/2022] [Accepted: 05/20/2022] [Indexed: 11/29/2022] Open
Abstract
Multi-subunit E3 ligases facilitate ubiquitin transfer by coordinating various substrate receptor subunits with a single catalytic center. Small molecules inducing targeted protein degradation have exploited such complexes, proving successful as therapeutics against previously undruggable targets. The C-terminal to LisH (CTLH) complex, also called the glucose-induced degradation deficient (GID) complex, is a multi-subunit E3 ligase complex highly conserved from Saccharomyces cerevisiae to humans, with roles in fundamental pathways controlling homeostasis and development in several species. However, we are only beginning to understand its mechanistic basis. Here, we review the literature of the CTLH complex from all organisms and place previous findings on individual subunits into context with recent breakthroughs on its structure and function.
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Huang YA, Hsu CH, Chiu HC, Hsi PY, Ho CT, Lo WL, Hwang E. Actin waves transport RanGTP to the neurite tip to regulate non-centrosomal microtubules in neurons. J Cell Sci 2020; 133:jcs241992. [PMID: 32253322 DOI: 10.1242/jcs.241992] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/17/2020] [Indexed: 12/18/2022] Open
Abstract
Microtubules (MTs) are the most abundant cytoskeleton in neurons, and control multiple facets of their development. While the MT-organizing center (MTOC) in mitotic cells is typically located at the centrosome, the MTOC in neurons switches to non-centrosomal sites. A handful of cellular components have been shown to promote non-centrosomal MT (ncMT) formation in neurons, yet the regulation mechanism remains unknown. Here, we demonstrate that the small GTPase Ran is a key regulator of ncMTs in neurons. Using an optogenetic tool that enables light-induced local production of RanGTP, we demonstrate that RanGTP promotes ncMT plus-end growth along the neurite. Additionally, we discovered that actin waves drive the anterograde transport of RanGTP. Pharmacological disruption of actin waves abolishes the enrichment of RanGTP and reduces growing ncMT plus-ends at the neurite tip. These observations identify a novel regulation mechanism for ncMTs and pinpoint an indirect connection between the actin and MT cytoskeletons in neurons.
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Affiliation(s)
- Yung-An Huang
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan 30068
| | - Chih-Hsuan Hsu
- Institute of Molecular Medicine and Bioengineering, National Chiao Tung University, Hsinchu, Taiwan 30068
| | - Ho-Chieh Chiu
- Institute of Molecular Medicine and Bioengineering, National Chiao Tung University, Hsinchu, Taiwan 30068
| | - Pei-Yu Hsi
- Institute of Molecular Medicine and Bioengineering, National Chiao Tung University, Hsinchu, Taiwan 30068
| | - Chris T Ho
- Institute of Molecular Medicine and Bioengineering, National Chiao Tung University, Hsinchu, Taiwan 30068
| | - Wei-Lun Lo
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan 30068
| | - Eric Hwang
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan 30068
- Institute of Molecular Medicine and Bioengineering, National Chiao Tung University, Hsinchu, Taiwan 30068
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, Taiwan 30068
- Center for Intelligent Drug Systems and Smart Bio-devices (IDS2B), National Chiao Tung University, Hsinchu, Taiwan 30068
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Bhute S, Sarmah D, Datta A, Rane P, Shard A, Goswami A, Borah A, Kalia K, Dave KR, Bhattacharya P. Molecular Pathogenesis and Interventional Strategies for Alzheimer's Disease: Promises and Pitfalls. ACS Pharmacol Transl Sci 2020; 3:472-488. [PMID: 32566913 DOI: 10.1021/acsptsci.9b00104] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Indexed: 12/16/2022]
Abstract
Alzheimer's disease (AD) is a debilitating disorder characterized by age-related dementia, which has no effective treatment to date. β-Amyloid depositions and hyperphosphorylated tau proteins are the main pathological hallmarks, along with oxidative stress, N-methyl-d-aspartate (NMDA) receptor-mediated excitotoxicity, and low levels of acetylcholine. Current pharmacotherapy for AD only provides symptomatic relief and limited improvement in cognitive functions. Many molecules have been explored that show promising outcomes in AD therapy and can regulate cellular survival through different pathways. To have a vivid approach to strategize the treatment regimen, AD physiopathology should be better explained considering diverse etiological factors in conjunction with biochemical disturbances. This Review attempts to discuss different disease modification approaches and address the novel therapeutic targets of AD that might pave the way for new drug discovery using the well-defined targets for therapy of the disease.
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Affiliation(s)
- Shashikala Bhute
- Department of Pharmacology and Toxicology,National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar-382355, Gujarat, India
| | - Deepaneeta Sarmah
- Department of Pharmacology and Toxicology,National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar-382355, Gujarat, India
| | - Aishika Datta
- Department of Pharmacology and Toxicology,National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar-382355, Gujarat, India
| | - Pallavi Rane
- Department of Pharmacology and Toxicology,National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar-382355, Gujarat, India
| | - Amit Shard
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar-382355, Gujarat, India
| | - Avirag Goswami
- Department of Neurology, Albert Einstein Medical Center, Philadelphia, Pennsylvania 19141, United States
| | - Anupom Borah
- Department of Life Science and Bioinformatics, Assam University, Silchar, Assam-788011, India
| | - Kiran Kalia
- Department of Pharmacology and Toxicology,National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar-382355, Gujarat, India
| | - Kunjan R Dave
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida 33136, United States
| | - Pallab Bhattacharya
- Department of Pharmacology and Toxicology,National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar-382355, Gujarat, India
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He B, Chen W, Zeng J, Tong W, Zheng P. MicroRNA-326 decreases tau phosphorylation and neuron apoptosis through inhibition of the JNK signaling pathway by targeting VAV1 in Alzheimer's disease. J Cell Physiol 2019; 235:480-493. [PMID: 31385301 DOI: 10.1002/jcp.28988] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 05/13/2019] [Accepted: 05/14/2019] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is a progressive and age-related neurological dysfunction. Abundant data have profiled microRNA (miR) patterns in healthy, aging brain, and in the moderate and late-stages of AD. Herein, this study aimed to explore whether miR-326 could influence neuron apoptosis in AD mice and how miR-326 functions in this process. The candidate differentially expressed gene VAV1 was obtained by microarray analysis, and miRNAs that could regulate VAV1 candidate gene were predicted. Luciferase activity determination confirmed VAV1 as a target gene of miR-326. AD mice models were established for investigating the effect of miR-326 on AD mice. The overexpression of miR-326 contributed to decreased time of the mice to find the platform and the escape latency and increased residence time on the target area. Besides, elevation of miR-326 decreased Aβ deposition and contents of Aβ1-40 and Aβ1-42 . Moreover, miR-326 overexpression increased neuron cell ability, mediated cell entry, and inhibited neuron apoptosis via JNK signaling pathway. Of crucial importance, miR-326 negatively regulated the expression of VAV1, inhibited tau phosphorylation, and blocked the activation of the JNK signaling pathway. Taken together these observations, we demonstrate that miR-326 improves cognitive function of AD mice and inhibits neuron apoptosis in AD mice through inactivation of the JNK signaling pathway by targeting VAV1. Based on those findings, miR-326 might exert promise as target for the treatment of AD.
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Affiliation(s)
- Bin He
- Department of Neurosurgery, Shanghai University of Medicine & Health Sciences, Shanghai, China
| | - Wei Chen
- Department of Neurosurgery, Shanghai University of Medicine & Health Sciences, Shanghai, China
| | - Jingsong Zeng
- Department of Neurosurgery, Shanghai Pudong New Area People's Hospital, Shanghai, China
| | - Wusong Tong
- Department of Neurosurgery, Shanghai Pudong New Area People's Hospital, Shanghai, China
| | - Ping Zheng
- Department of Neurosurgery, Shanghai Pudong New Area People's Hospital, Shanghai, China
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The mammalian CTLH complex is an E3 ubiquitin ligase that targets its subunit muskelin for degradation. Sci Rep 2019; 9:9864. [PMID: 31285494 PMCID: PMC6614414 DOI: 10.1038/s41598-019-46279-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/17/2019] [Indexed: 12/15/2022] Open
Abstract
The multi-subunit C-terminal to LisH (CTLH) complex is the mammalian homologue of the yeast Gid E3 ubiquitin ligase complex. In this study, we investigated the human CTLH complex and characterized its E3 ligase activity. We confirm that the complex immunoprecipitated from human cells comprises RanBPM, ARMC8 α/β, muskelin, WDR26, GID4 and the RING domain proteins RMND5A and MAEA. We find that loss of expression of individual subunits compromises the stability of other complex members and that MAEA and RMND5A protein levels are interdependent. Using in vitro ubiquitination assays, we demonstrate that the CTLH complex has E3 ligase activity which is dependent on RMND5A and MAEA. We report that the complex can pair with UBE2D1, UBE2D2 and UBE2D3 E2 enzymes and that recombinant RMND5A mediates K48 and K63 poly-ubiquitin chains. Finally, we show a proteasome-dependent increase in the protein levels of CTLH complex member muskelin in RMND5A KO cells. Furthermore, muskelin ubiquitination is dependent on RMND5A, suggesting that it may be a target of the complex. Overall, we further the characterization of the CTLH complex as an E3 ubiquitin ligase complex in human cells and reveal a potential autoregulation mechanism.
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Salemi LM, Maitland MER, McTavish CJ, Schild-Poulter C. Cell signalling pathway regulation by RanBPM: molecular insights and disease implications. Open Biol 2018; 7:rsob.170081. [PMID: 28659384 PMCID: PMC5493780 DOI: 10.1098/rsob.170081] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 06/01/2017] [Indexed: 12/25/2022] Open
Abstract
RanBPM (Ran-binding protein M, also called RanBP9) is an evolutionarily conserved, ubiquitous protein which localizes to both nucleus and cytoplasm. RanBPM has been implicated in the regulation of a number of signalling pathways to regulate several cellular processes such as apoptosis, cell adhesion, migration as well as transcription, and plays a critical role during development. In addition, RanBPM has been shown to regulate pathways implicated in cancer and Alzheimer's disease, implying that RanBPM has important functions in both normal and pathological development. While its functions in these processes are still poorly understood, RanBPM has been identified as a component of a large complex, termed the CTLH (C-terminal to LisH) complex. The yeast homologue of this complex functions as an E3 ubiquitin ligase that targets enzymes of the gluconeogenesis pathway. While the CTLH complex E3 ubiquitin ligase activity and substrates still remain to be characterized, the high level of conservation between the complexes in yeast and mammals infers that the CTLH complex could also serve to promote the degradation of specific substrates through ubiquitination, therefore suggesting the possibility that RanBPM's various functions may be mediated through the activity of the CTLH complex.
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Affiliation(s)
- Louisa M Salemi
- Robarts Research Institute, Department of Biochemistry, Schulich School of Medicine and Dentistry, The University of Western Ontario, 1151 Richmond Street North, London, Ontario, Canada N6A 5B7
| | - Matthew E R Maitland
- Robarts Research Institute, Department of Biochemistry, Schulich School of Medicine and Dentistry, The University of Western Ontario, 1151 Richmond Street North, London, Ontario, Canada N6A 5B7
| | - Christina J McTavish
- Robarts Research Institute, Department of Biochemistry, Schulich School of Medicine and Dentistry, The University of Western Ontario, 1151 Richmond Street North, London, Ontario, Canada N6A 5B7
| | - Caroline Schild-Poulter
- Robarts Research Institute, Department of Biochemistry, Schulich School of Medicine and Dentistry, The University of Western Ontario, 1151 Richmond Street North, London, Ontario, Canada N6A 5B7
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8
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Woo JA, Liu T, Zhao X, Trotter C, Yrigoin K, Cazzaro S, Narvaez ED, Khan H, Witas R, Bukhari A, Makati K, Wang X, Dickey C, Kang DE. Enhanced tau pathology via RanBP9 and Hsp90/Hsc70 chaperone complexes. Hum Mol Genet 2017; 26:3973-3988. [PMID: 29016855 PMCID: PMC6075219 DOI: 10.1093/hmg/ddx284] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/04/2017] [Accepted: 07/14/2017] [Indexed: 12/26/2022] Open
Abstract
Accumulation of amyloid β (Aβ) and tau represent the two major pathological hallmarks of Alzheimer's disease (AD). Despite the critical importance of Aβ accumulation as an early event in AD pathogenesis, multiple lines of evidence indicate that tau is required to mediate Aβ-induced neurotoxic signals in neurons. We have previously shown that the scaffolding protein Ran-binding protein 9 (RanBP9), which is highly elevated in brains of AD and AD mouse models, both enhances Aβ production and mediates Aβ-induced neurotoxicity. However, it is unknown whether and how RanBP9 transmits Aβ-induced neurotoxic signals to tau. Here we show for the first time that overexpression or knockdown of RanBP9 directly enhances and reduces tau levels, respectively, in vitro and in vivo. Such changes in tau levels are associated with the ability of RanBP9 to physically interact with tau and heat shock protein 90/heat shock cognate 70 (Hsp90/Hsc70) complexes. Meanwhile, both RanBP9 and tau levels are simultaneously reduced by Hsp90 or Hsc70 inhibitors, whereas overexpression or knockdown of RanBP9 significantly diminishes the anti-tau potency of Hsp90/Hsc70 inhibitors as well as Hsc70 variants (WT & E175S). Further, RanBP9 increases the capacity for Hsp90 and Hsc70 complexes to bind ATP and enhances their ATPase activities in vitro. These observations in vitro and cell lines are recapitulated in primary neurons and in vivo, as genetic reduction in RanBP9 not only ameliorates tauopathy in Tau-P301S mice but also rescues the deficits in synaptic integrity and plasticity.
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Affiliation(s)
- Jung A Woo
- USF Health Byrd Alzheimer’s Institute
- Department of Molecular Medicine
| | - Tian Liu
- USF Health Byrd Alzheimer’s Institute
- Department of Molecular Medicine
| | - Xingyu Zhao
- USF Health Byrd Alzheimer’s Institute
- Department of Molecular Medicine
| | - Courtney Trotter
- USF Health Byrd Alzheimer’s Institute
- Department of Molecular Medicine
| | | | | | | | | | | | | | | | - Xinming Wang
- USF Health Byrd Alzheimer’s Institute
- Department of Molecular Pharmacology and Physiology, University of South Florida, Morsani College of Medicine, Tampa, FL 33613, USA
| | - Chad Dickey
- USF Health Byrd Alzheimer’s Institute
- Department of Molecular Medicine
- James A. Haley Veteran’s Administration Hospital, Research Division, Tampa, FL 33612, USA
| | - David E Kang
- USF Health Byrd Alzheimer’s Institute
- Department of Molecular Medicine
- James A. Haley Veteran’s Administration Hospital, Research Division, Tampa, FL 33612, USA
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Das S, Suresh B, Kim HH, Ramakrishna S. RanBPM: a potential therapeutic target for modulating diverse physiological disorders. Drug Discov Today 2017; 22:1816-1824. [PMID: 28847759 DOI: 10.1016/j.drudis.2017.08.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 06/26/2017] [Accepted: 08/21/2017] [Indexed: 02/06/2023]
Abstract
The Ran-binding protein microtubule-organizing center (RanBPM) is a highly conserved nucleocytoplasmic protein involved in a variety of intracellular signaling pathways that control diverse cellular functions. RanBPM interacts with proteins that are linked to various diseases, including Alzheimer's disease (AD), schizophrenia (SCZ), and cancer. In this article, we define the characteristics of the scaffolding protein RanBPM and focus on its interaction partners in diverse physiological disorders, such as neurological diseases, fertility disorders, and cancer.
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Affiliation(s)
- Soumyadip Das
- Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, 04763, South Korea
| | - Bharathi Suresh
- Department of Pharmacology, Yonsei University College of Medicine, Seoul, 03722, South Korea.
| | - Hyongbum Henry Kim
- Department of Pharmacology, Yonsei University College of Medicine, Seoul, 03722, South Korea; Brain Korea 21 Plus Project for Medical Sciences, Yonsei University College of Medicine, Seoul, 03722, South Korea; Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea; Center for Nanomedicine, Institute for Basic Science (IBS), Seoul, 03722, South Korea.
| | - Suresh Ramakrishna
- Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, 04763, South Korea; College of Medicine, Hanyang University, Seoul, 04763, South Korea.
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Millan MJ. Linking deregulation of non-coding RNA to the core pathophysiology of Alzheimer's disease: An integrative review. Prog Neurobiol 2017; 156:1-68. [PMID: 28322921 DOI: 10.1016/j.pneurobio.2017.03.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 03/09/2017] [Accepted: 03/09/2017] [Indexed: 02/06/2023]
Abstract
The human genome encodes a vast repertoire of protein non-coding RNAs (ncRNA), some specific to the brain. MicroRNAs, which interfere with the translation of target mRNAs, are of particular interest since their deregulation has been implicated in neurodegenerative disorders like Alzheimer's disease (AD). However, it remains challenging to link the complex body of observations on miRNAs and AD into a coherent framework. Using extensive graphical support, this article discusses how a diverse panoply of miRNAs convergently and divergently impact (and are impacted by) core pathophysiological processes underlying AD: neuroinflammation and oxidative stress; aberrant generation of β-amyloid-42 (Aβ42); anomalies in the production, cleavage and post-translational marking of Tau; impaired clearance of Aβ42 and Tau; perturbation of axonal organisation; disruption of synaptic plasticity; endoplasmic reticulum stress and the unfolded protein response; mitochondrial dysfunction; aberrant induction of cell cycle re-entry; and apoptotic loss of neurons. Intriguingly, some classes of miRNA provoke these cellular anomalies, whereas others act in a counter-regulatory, protective mode. Moreover, changes in levels of certain species of miRNA are a consequence of the above-mentioned anomalies. In addition to miRNAs, circular RNAs, piRNAs, long non-coding RNAs and other types of ncRNA are being increasingly implicated in AD. Overall, a complex mesh of deregulated and multi-tasking ncRNAs reciprocally interacts with core pathophysiological mechanisms underlying AD. Alterations in ncRNAs can be detected in CSF and the circulation as well as the brain and are showing promise as biomarkers, with the ultimate goal clinical exploitation as targets for novel modes of symptomatic and course-altering therapy.
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Affiliation(s)
- Mark J Millan
- Centre for Therapeutic Innovation in Neuropsychiatry, institut de recherche Servier, 125 chemin de ronde, 78290 Croissy sur Seine, France.
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TFEB Overexpression in the P301S Model of Tauopathy Mitigates Increased PHF1 Levels and Lipofuscin Puncta and Rescues Memory Deficits. eNeuro 2016; 3:eN-NWR-0042-16. [PMID: 27257626 PMCID: PMC4876487 DOI: 10.1523/eneuro.0042-16.2016] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 05/05/2016] [Accepted: 05/06/2016] [Indexed: 12/22/2022] Open
Abstract
Transcription factor EB (TFEB) was recently shown to be a master regulator of autophagy lysosome pathway. Here, we successfully generated and characterized transgenic mice overexpressing flag-TFEB. Enhanced autophagy in the flag-TFEB transgenic mice was confirmed by an increase in the cellular autophagy markers, as determined by both immunoblots and transmission electron microscopy. Surprisingly, in the flag-TFEB mice we observed increased activity of senescence-associated β-galactosidase by ∼66% of neurons in the cortex (p < 0.001) and 73% of neurons in the hippocampus (p < 0.001). More importantly, flag-TFEB expression remarkably reduced the levels of paired-helical filament (PHF)-tau from 372% in the P301S model of tauopathy to 171% (p < 0.001) in the cortex, and from 436% to 212% (p < 0.001) in the hippocampus. Significantly, reduced levels of NeuN in the cortex (38%, p < 0.001) and hippocampus (25%, p < 0.05) of P301S mice were almost completely restored to WT levels in the P301S/flag-TFEB double-transgenic mice. Also, levels of spinophilin in both the cortex (p < 0.001) and hippocampus (p < 0.001) were restored almost to WT levels. Most importantly, the age-associated lipofuscin granules, which are generally presumed to be nondegradable, were reduced by 57% (p < 0.001) in the cortex and by 55% (p < 0.001) in the hippocampus in the double-transgenic mice. Finally, TFEB overexpression in the P301S mice markedly reversed learning deficits in terms of spatial memory (Barnes maze), as well as working and reference memories (T maze). These data suggest that the overexpression of TFEB can reliably enhance autophagy in vivo, reduce levels of PHF-tau, and thereby reverse the deposition of lipofuscin granules and memory deficits.
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Woo JA, Boggess T, Uhlar C, Wang X, Khan H, Cappos G, Joly-Amado A, De Narvaez E, Majid S, Minamide LS, Bamburg JR, Morgan D, Weeber E, Kang DE. RanBP9 at the intersection between cofilin and Aβ pathologies: rescue of neurodegenerative changes by RanBP9 reduction. Cell Death Dis 2015; 6:1676. [PMID: 25741591 PMCID: PMC4385917 DOI: 10.1038/cddis.2015.37] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Revised: 01/05/2015] [Accepted: 01/19/2015] [Indexed: 12/21/2022]
Abstract
Molecular pathways underlying the neurotoxicity and production of amyloid β protein (Aβ) represent potentially promising therapeutic targets for Alzheimer's disease (AD). We recently found that overexpression of the scaffolding protein RanBP9 increases Aβ production in cell lines and in transgenic mice while promoting cofilin activation and mitochondrial dysfunction. Translocation of cofilin to mitochondria and induction of cofilin–actin pathology require the activation/dephosphorylation of cofilin by Slingshot homolog 1 (SSH1) and cysteine oxidation of cofilin. In this study, we found that endogenous RanBP9 positively regulates SSH1 levels and mediates Aβ-induced translocation of cofilin to mitochondria and induction of cofilin–actin pathology in cultured cells, primary neurons, and in vivo. Endogenous level of RanBP9 was also required for Aβ-induced collapse of growth cones in immature neurons (days in vitro 9 (DIV9)) and depletion of synaptic proteins in mature neurons (DIV21). In vivo, amyloid precursor protein (APP)/presenilin-1 (PS1) mice exhibited 3.5-fold increased RanBP9 levels, and RanBP9 reduction protected against cofilin–actin pathology, synaptic damage, gliosis, and Aβ accumulation associated with APP/PS1 mice. Brains slices derived from APP/PS1 mice showed significantly impaired long-term potentiation (LTP), and RanBP9 reduction significantly enhanced paired pulse facilitation and LTP, as well as partially rescued contextual memory deficits associated with APP/PS1 mice. Therefore, these results underscore the critical importance of endogenous RanBP9 not only in Aβ accumulation but also in mediating the neurotoxic actions of Aβ at the level of synaptic plasticity, mitochondria, and cofilin–actin pathology via control of the SSH1-cofilin pathway in vivo.
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Affiliation(s)
- J A Woo
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - T Boggess
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - C Uhlar
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - X Wang
- Department of Molecular Pharmacology and Physiology, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - H Khan
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - G Cappos
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - A Joly-Amado
- Department of Molecular Pharmacology and Physiology, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - E De Narvaez
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - S Majid
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - L S Minamide
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - J R Bamburg
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - D Morgan
- Department of Molecular Pharmacology and Physiology, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - E Weeber
- Department of Molecular Pharmacology and Physiology, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - D E Kang
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
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Wang R, Wang H, Carrera I, Xu S, Lakshmana MK. COPS5 protein overexpression increases amyloid plaque burden, decreases spinophilin-immunoreactive puncta, and exacerbates learning and memory deficits in the mouse brain. J Biol Chem 2015; 290:9299-309. [PMID: 25713139 DOI: 10.1074/jbc.m114.595926] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Indexed: 01/05/2023] Open
Abstract
Brain accumulation of neurotoxic amyloid β (Aβ) peptide because of increased processing of amyloid precursor protein (APP), resulting in loss of synapses and neurodegeneration, is central to the pathogenesis of Alzheimer disease (AD). Therefore, the identification of molecules that regulate Aβ generation and those that cause synaptic damage is crucial for future therapeutic approaches for AD. We demonstrated previously that COPS5 regulates Aβ generation in neuronal cell lines in a RanBP9-dependent manner. Consistent with the data from cell lines, even by 6 months, COPS5 overexpression in APΔE9 mice (APΔE9/COPS5-Tg) significantly increased Aβ40 levels by 32% (p < 0.01) in the cortex and by 28% (p < 0.01) in the hippocampus, whereas the increases for Aβ42 were 37% (p < 0.05) and 34% (p < 0.05), respectively. By 12 months, the increase was even more robust. Aβ40 levels increased by 63% (p < 0.001) in the cortex and by 65% (p < 0.001) in the hippocampus. Similarly, Aβ42 levels were increased by 69% (p < 0.001) in the cortex and by 71% (p < 0.011) in the hippocampus. Increased Aβ levels were translated into an increased amyloid plaque burden both in the cortex (54%, p < 0.01) and hippocampus (64%, p < 0.01). Interestingly, COPS5 overexpression increased RanBP9 levels in the brain, which, in turn, led to increased amyloidogenic processing of APP, as reflected by increased levels of sAPPβ and decreased levels of sAPPα. Furthermore, COPS5 overexpression reduced spinophilin in both the cortex (19%, p < 0.05) and the hippocampus (20%, p < 0.05), leading to significant deficits in learning and memory skills. Therefore, like RanBP9, COPS5 also plays a pivotal role in amyloid pathology in vivo.
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Affiliation(s)
- Ruizhi Wang
- From the Section of Neurobiology, Torrey Pines Institute for Molecular Studies, Port Saint Lucie, Florida 34987
| | - Hongjie Wang
- From the Section of Neurobiology, Torrey Pines Institute for Molecular Studies, Port Saint Lucie, Florida 34987
| | - Ivan Carrera
- the Department of Neuroscience, Euroespes Biotechnology, Poligono de Bergondo, Nave F, 15165A, A Coruna, Spain, and
| | - Shaohua Xu
- the Florida Institute of Technology, Melbourne, Florida 32901
| | - Madepalli K Lakshmana
- From the Section of Neurobiology, Torrey Pines Institute for Molecular Studies, Port Saint Lucie, Florida 34987,
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14
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BAE JOONSEOL, KIM JASONYONGHA, PARK BYUNGLAE, CHEONG HYUNSUB, KIM JEONGHYUN, NAMGOONG SUHG, KIM JION, PARK CHULSOO, KIM BONGJO, LEE CHEOLSOON, LEE MIGYUNG, CHOI WOOHYUK, SHIN TAEMIN, HWANG JAEUK, SHIN HYOUNGDOO, WOO SUNGIL. Investigating the potential genetic association between RANBP9 polymorphisms and the risk of schizophrenia. Mol Med Rep 2014; 11:2975-80. [DOI: 10.3892/mmr.2014.3045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 11/05/2014] [Indexed: 11/05/2022] Open
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15
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Henriques AG, Oliveira JM, Carvalho LP, da Cruz E Silva OAB. Aβ Influences Cytoskeletal Signaling Cascades with Consequences to Alzheimer's Disease. Mol Neurobiol 2014; 52:1391-1407. [PMID: 25344315 DOI: 10.1007/s12035-014-8913-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 09/28/2014] [Indexed: 01/16/2023]
Abstract
Abnormal signal transduction events can impact upon the cytoskeleton, affecting the actin and microtubule networks with direct relevance to Alzheimer's disease (AD). Cytoskeletal anomalies, in turn, promote atypical neuronal responses, with consequences for cellular organization and function. Neuronal cytoskeletal modifications in AD include neurofibrillary tangles, which result from aggregates of hyperphosphorylated tau protein. The latter is a microtubule (MT)-binding protein, whose abnormal phosphorylation leads to MT instability and consequently provokes irregularities in the neuronal trafficking pathways. Early stages of AD are also characterized by synaptic dysfunction and loss of dendritic spines, which correlate with cognitive deficit and impaired brain function. Actin dynamics has a prominent role in maintaining spine plasticity and integrity, thus providing the basis for memory and learning processes. Hence, factors that disrupt both actin and MT network dynamics will compromise neuronal function and survival. The peptide Aβ is the major component of senile plaques and has been described as a pivotal mediator of neuronal dystrophy and synaptic loss in AD. Here, we review Aβ-mediated effects on both MT and actin networks and focus on the relevance of the elicited cytoskeletal signaling events targeted in AD pathology.
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Affiliation(s)
- Ana Gabriela Henriques
- Laboratório de Neurociências e Sinalização, Centro de Biologia Celular, SACS, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Joana Machado Oliveira
- Laboratório de Neurociências e Sinalização, Centro de Biologia Celular, SACS, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Liliana Patrícia Carvalho
- Laboratório de Neurociências e Sinalização, Centro de Biologia Celular, SACS, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Odete A B da Cruz E Silva
- Laboratório de Neurociências e Sinalização, Centro de Biologia Celular, SACS, Universidade de Aveiro, 3810-193, Aveiro, Portugal.
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16
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Wang R, Palavicini JP, Wang H, Maiti P, Bianchi E, Xu S, Lloyd BN, Dawson-Scully K, Kang DE, Lakshmana MK. RanBP9 overexpression accelerates loss of dendritic spines in a mouse model of Alzheimer's disease. Neurobiol Dis 2014; 69:169-79. [PMID: 24892886 DOI: 10.1016/j.nbd.2014.05.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 04/14/2014] [Accepted: 05/22/2014] [Indexed: 01/08/2023] Open
Abstract
We previously demonstrated that RanBP9 overexpression increased Aβ generation and amyloid plaque burden, subsequently leading to robust reductions in the levels of several synaptic proteins as well as deficits in the learning and memory skills in a mouse model of Alzheimer's disease (AD). In the present study, we found striking reduction of spinophilin-immunoreactive puncta (52%, p<0.001) and spinophilin area (62.5%, p<0.001) in the primary cortical neurons derived from RanBP9 transgenic mice (RanBP9-Tg) compared to wild-type (WT) neurons. Similar results were confirmed in WT cortical neurons transfected with EGFP-RanBP9. At 6-months of age, the total spine density in the cortex of RanBP9 single transgenic, APΔE9 double transgenic and APΔE9/RanBP9 triple transgenic mice was similar to WT mice. However, in the hippocampus the spine density was significantly reduced (27%, p<0.05) in the triple transgenic mice compared to WT mice due to reduced number of thin spines (33%, p<0.05) and mushroom spines (22%, p<0.05). This suggests that RanBP9 overexpression in the APΔE9 mice accelerates loss of spines and that the hippocampus is more vulnerable. At 12-months of age, the cortex showed significant reductions in total spine density in the RanBP9 (22%, p<0.05), APΔE9 (19%, p<0.05) and APΔE9/RanBP9 (33%, p<0.01) mice compared to WT controls due to reductions in mushroom and thin spines. Similarly, in the hippocampus the total spine density was reduced in the RanBP9 (23%, p<0.05), APΔE9 (26%, p<0.05) and APΔE9/RanBP9 (39%, p<0.01) mice due to reductions in thin and mushroom spines. Most importantly, RanBP9 overexpression in the APΔE9 mice further exacerbated the reductions in spine density in both the cortex (14%, p<0.05) and the hippocampus (16%, p<0.05). Because dendritic spines are considered physical traces of memory, loss of spines due to RanBP9 provided the physical basis for the learning and memory deficits. Since RanBP9 protein levels are increased in AD brains, RanBP9 might play a crucial role in the loss of spines and synapses in AD.
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Affiliation(s)
- Ruizhi Wang
- Section of Neurobiology, Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port Saint Lucie, FL 34987, USA
| | - Juan Pablo Palavicini
- Section of Neurobiology, Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port Saint Lucie, FL 34987, USA
| | - Hongjie Wang
- Section of Neurobiology, Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port Saint Lucie, FL 34987, USA
| | - Panchanan Maiti
- University of Tennessee Health Science Center, Department of Neurology, 415 Link Building, TN, USA
| | - Elisabetta Bianchi
- Laboratory of Immuneregulation, Department of Immunology, Institut Pasteur, 25 rue du Dr. Roux, 75724 Paris, France
| | - Shaohua Xu
- Florida Institute of Technology, 150 West University Blvd, Melbourne, FL 32901, USA
| | - B N Lloyd
- Department of Biological Sciences, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, USA
| | - Ken Dawson-Scully
- Department of Biological Sciences, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, USA
| | - David E Kang
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, 4001 E. Fletcher Ave. - MDC36, Tampa, FL 33612, USA
| | - Madepalli K Lakshmana
- Section of Neurobiology, Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port Saint Lucie, FL 34987, USA.
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Fragile X mental retardation protein controls synaptic vesicle exocytosis by modulating N-type calcium channel density. Nat Commun 2014; 5:3628. [PMID: 24709664 PMCID: PMC3982139 DOI: 10.1038/ncomms4628] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 03/12/2014] [Indexed: 12/25/2022] Open
Abstract
Fragile X syndrome (FXS), the most common heritable form of mental retardation, is
characterized by synaptic dysfunction. Synaptic transmission depends critically on
presynaptic calcium entry via voltage-gated calcium (CaV) channels. Here
we show that the functional expression of neuronal N-type CaV channels
(CaV2.2) is
regulated by fragile X mental retardation
protein (FMRP).
We find that FMRP knockdown in
dorsal root ganglion neurons increases CaV channel density in somata and
in presynaptic terminals. We then show that FMRP controls CaV2.2 surface expression by targeting the channels
to the proteasome for degradation. The interaction between FMRP and CaV2.2 occurs between the carboxy-terminal domain
of FMRP and domains of
CaV2.2 known to
interact with the neurotransmitter release machinery. Finally, we show that
FMRP controls synaptic
exocytosis via CaV2.2
channels. Our data indicate that FMRP is a potent regulator of presynaptic activity, and its loss
is likely to contribute to synaptic dysfunction in FXS. Mutations in the fragile X mental retardation protein are
implicated in synaptic dysfunction in fragile X syndrome. Here, Ferron et al.
show that fragile X mental retardation protein maintains proper neurotransmission by
regulating the density of N-type calcium channels in the presynaptic terminal.
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Barbato C, Pezzola S, Caggiano C, Antonelli M, Frisone P, Ciotti MT, Ruberti F. A lentiviral sponge for miR-101 regulates RanBP9 expression and amyloid precursor protein metabolism in hippocampal neurons. Front Cell Neurosci 2014; 8:37. [PMID: 24592211 PMCID: PMC3923151 DOI: 10.3389/fncel.2014.00037] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 01/25/2014] [Indexed: 12/22/2022] Open
Abstract
Neurodegeneration associated with amyloid β (Aβ) peptide accumulation, synaptic loss, and memory impairment are pathophysiological features of Alzheimer's disease (AD). Numerous microRNAs regulate amyloid precursor protein (APP) expression and metabolism. We previously reported that miR-101 is a negative regulator of APP expression in cultured hippocampal neurons. In this study, a search for predicted APP metabolism-associated miR-101 targets led to the identification of a conserved miR-101 binding site within the 3′ untranslated region (UTR) of the mRNA encoding Ran-binding protein 9 (RanBP9). RanBP9 increases APP processing by β-amyloid converting enzyme 1 (BACE1), secretion of soluble APPβ (sAPPβ), and generation of Aβ. MiR-101 significantly reduced reporter gene expression when co-transfected with a RanBP9 3′-UTR reporter construct, while site-directed mutagenesis of the predicted miR-101 target site eliminated the reporter response. To investigate the effect of stable inhibition of miR-101 both in vitro and in vivo, a microRNA sponge was developed to bind miR-101 and derepress its targets. Four tandem bulged miR-101 responsive elements (REs), located downstream of the enhanced green fluorescence protein (EGFP) open reading frame and driven by the synapsin promoter, were placed in a lentiviral vector to create the pLSyn-miR-101 sponge. Delivery of the sponge to primary hippocampal neurons significantly increased both APP and RanBP9 expression, as well as sAPPβ levels in the conditioned medium. Importantly, silencing of endogenous RanBP9 reduced sAPPβ levels in miR-101 sponge-containing hippocampal cultures, indicating that miR-101 inhibition may increase amyloidogenic processing of APP by RanBP9. Lastly, the impact of miR-101 on its targets was demonstrated in vivo by intrahippocampal injection of the pLSyn-miR-101 sponge into C57BL6 mice. This study thus provides the basis for studying the consequences of long-term miR-101 inhibition on the pathology of AD.
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Affiliation(s)
- Christian Barbato
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR) Rome, Italy
| | - Silvia Pezzola
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR) Rome, Italy
| | - Cinzia Caggiano
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR) Rome, Italy
| | - Martina Antonelli
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR) Rome, Italy
| | - Paola Frisone
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR) Rome, Italy
| | - Maria Teresa Ciotti
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR) Rome, Italy
| | - Francesca Ruberti
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR) Rome, Italy
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Subramanian M, Hayes CD, Thome JJ, Thorp E, Matsushima GK, Herz J, Farber DL, Liu K, Lakshmana M, Tabas I. An AXL/LRP-1/RANBP9 complex mediates DC efferocytosis and antigen cross-presentation in vivo. J Clin Invest 2014; 124:1296-308. [PMID: 24509082 DOI: 10.1172/jci72051] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 11/21/2013] [Indexed: 01/02/2023] Open
Abstract
The phagocytosis of apoptotic cells (ACs), or efferocytosis, by DCs is critical for self-tolerance and host defense. Although many efferocytosis-associated receptors have been described in vitro, the functionality of these receptors in vivo has not been explored in depth. Using a spleen efferocytosis assay and targeted genetic deletion in mice, we identified a multiprotein complex--composed of the receptor tyrosine kinase AXL, LDL receptor-related protein-1 (LRP-1), and RAN-binding protein 9 (RANBP9)--that mediates DC efferocytosis and antigen cross-presentation. We found that AXL bound ACs, but required LRP-1 to trigger internalization, in murine CD8α+ DCs and human-derived DCs. AXL and LRP-1 did not interact directly, but relied on RANBP9, which bound both AXL and LRP-1, to form the complex. In a coculture model of antigen presentation, the AXL/LRP-1/RANBP9 complex was used by DCs to cross-present AC-associated antigens to T cells. Furthermore, in a murine model of herpes simplex virus-1 infection, mice lacking DC-specific LRP-1, AXL, or RANBP9 had increased AC accumulation, defective viral antigen-specific CD8+ T cell activation, enhanced viral load, and decreased survival. The discovery of this multiprotein complex that mediates functionally important DC efferocytosis in vivo may have implications for future studies related to host defense and DC-based vaccines.
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20
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RanBP9 overexpression reduces dendritic arbor and spine density. Neuroscience 2014; 265:253-62. [PMID: 24486966 DOI: 10.1016/j.neuroscience.2014.01.045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 01/22/2014] [Accepted: 01/22/2014] [Indexed: 11/21/2022]
Abstract
RanBP9 is a multi-domain scaffolding protein known to integrate extracellular signaling with intracellular targets. We previously demonstrated that RanBP9 enhances Aβ generation and amyloid plaque burden which results in loss of specific pre- and postsynaptic proteins in vivo in a transgenic mouse model. Additionally, we showed that the levels of spinophilin, a marker of dendritic spines were inversely proportional to the RanBP9 protein levels within the synaptosomes isolated from AD brains. In the present study, we found reduced dendritic intersections within the layer 6 pyramidal neurons of the cortex as well as the hippocampus of RanBP9 transgenic mice compared to age-matched wild-type (WT) controls at 12 months of age but not at 6months. Similarly, the dendritic spine numbers were reduced in the cortex at only 12 months of age by 30% (p<0.01), but not at 6months. In the hippocampus also the spine densities were reduced at 12 months of age (38%, p<0.01) in the RanBP9 transgenic mice. Interestingly, the levels of phosphorylated form of cofilin, an actin binding protein that plays crucial role in the regulation of spine numbers were significantly decreased in the cortical synaptosomes at only 12months of age by 26% (p<0.01). In the hippocampal synaptosomes, the decrease in cofilin levels were 36% (p<0.01) at 12 months of age. Thus dendritic arbor and spine density were directly correlated to the levels of phosphorylated form of cofilin in the RanBP9 transgenic mice. Similarly, cortical synaptosomes showed a 20% (p<0.01) reduction in the levels of spinophilin in the RanBP9 transgenic mice. These results provided the physical basis for the loss of synaptic proteins by RanBP9 and most importantly it also explains the impaired spatial learning and memory skills previously observed in the RanBP9 transgenic mice.
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21
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Wang H, Wang R, Xu S, Lakshmana MK. RanBP9 overexpression accelerates loss of pre and postsynaptic proteins in the APΔE9 transgenic mouse brain. PLoS One 2014; 9:e85484. [PMID: 24454876 PMCID: PMC3891818 DOI: 10.1371/journal.pone.0085484] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 11/27/2013] [Indexed: 12/02/2022] Open
Abstract
There is now compelling evidence that the neurodegenerative process in Alzheimer's disease (AD) begins in synapses. Loss of synaptic proteins and functional synapses in the amyloid precursor protein (APP) transgenic mouse models of AD is well established. However, what is the earliest age at which such loss of synapses occurs, and whether known markers of AD progression accelerate functional deficits is completely unknown. We previously showed that RanBP9 overexpression leads to robustly increased amyloid β peptide (Aβ) generation leading to enhanced amyloid plaque burden in a mouse model of AD. In this study we compared synaptic protein levels among four genotypes of mice, i.e., RanBP9 single transgenic (Ran), APΔE9 double transgenic (Dbl), APΔE9/RanBP9 triple transgenic (Tpl) and wild-type (WT) controls. We found significant reductions in the levels of synaptic proteins in both cortex and hippocampus of 5- and 6-months-old but not 3- or 4-months-old mice. Specifically, at 5-months of age, rab3A was reduced in the triple transgenic mice only in the cortex by 25% (p<0.05) and gap43 levels were reduced only in the hippocampus by 44% (p<0.01) compared to wild-type (WT) controls. Interestingly, RanBP9 overexpression in the Tpl mice reduced gap43 levels by a further 31% (p<0.05) compared to APΔE9 mice. RanBP9 also further decreased the levels of drebrin in the hippocampus by 32% (p<0.01) and chromogranin in the cortex by 24% (p<0.05) compared to APΔE9 mice. At 6-months of age, RanBP9 expression in the cortex led to further reduction of rab3A by 30% (p<0.05) and drebrin by 38% (p<0.01) compared to APΔE9 mice. RanBP9 also increased Aβ oligomers in the cortex at 6 months. Similarly, in the hippocampus, RanBP9 expression further reduced rab3A levels by 36% (p<0.01) and drebrin levels by 33% (p<0.01). Taken together these data suggest that RanBP9 overexpression accelerates loss of synaptic proteins in the mouse brain.
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Affiliation(s)
- Hongjie Wang
- Section of Neurobiology, Torrey Pines Institute for Molecular Studies, Port Saint Lucie, Florida, United States of America
| | - Ruizhi Wang
- Section of Neurobiology, Torrey Pines Institute for Molecular Studies, Port Saint Lucie, Florida, United States of America
| | - Shaohua Xu
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, Florida, United States of America
| | - Madepalli K. Lakshmana
- Section of Neurobiology, Torrey Pines Institute for Molecular Studies, Port Saint Lucie, Florida, United States of America
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Roh SE, Woo JA, Lakshmana MK, Uhlar C, Ankala V, Boggess T, Liu T, Hong YH, Mook-Jung I, Kim SJ, Kang DE. Mitochondrial dysfunction and calcium deregulation by the RanBP9-cofilin pathway. FASEB J 2013; 27:4776-89. [PMID: 23982146 DOI: 10.1096/fj.13-234765] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Mitochondrial dysfunction and synaptic damage are important features of Alzheimer's disease (AD) associated with amyloid β (Aβ) and tau. We reported previously that the scaffolding protein RanBP9, which is overall increased in brains of patients with AD and in mutant APP transgenic mice, simultaneously promotes Aβ generation and focal adhesion disruption by accelerating the endocytosis of APP and β1-integrin, respectively. Moreover, RanBP9 induces neurodegeneration in vitro and in vivo and mediates Aβ-induced neurotoxicity. Here we show in primary hippocampal neurons that RanBP9 potentiates Aβ-induced reactive oxygen species (ROS) overproduction, apoptosis, and calcium deregulation. Analyses of calcium-handling measures demonstrate that RanBP9 selectively delays the clearance of cytosolic Ca(2+) mediated by the mitochondrial calcium uniporter through a process involving the translocation of cofilin into mitochondria and oxidative mechanisms. Further, RanBP9 retards the anterograde axonal transport of mitochondria in primary neurons and decreases synaptic mitochondrial activity in brain. These data indicate that RanBP9, cofilin, and Aβ mimic and potentiate each other to produce mitochondrial dysfunction, ROS overproduction, and calcium deregulation, which leads to neurodegenerative changes reminiscent of those seen in AD.
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Affiliation(s)
- Seung-Eon Roh
- 1Department of Molecular Medicine, USF Health Byrd Institute, 4001 E. Fletcher Ave., Tampa, FL 33613, USA.
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23
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Wang H, Dey D, Carrera I, Minond D, Bianchi E, Xu S, Lakshmana MK. COPS5 (Jab1) protein increases β site processing of amyloid precursor protein and amyloid β peptide generation by stabilizing RanBP9 protein levels. J Biol Chem 2013; 288:26668-77. [PMID: 23926111 DOI: 10.1074/jbc.m113.476689] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Increased processing of amyloid precursor protein (APP) and accumulation of neurotoxic amyloid β peptide (Aβ) in the brain is central to the pathogenesis of Alzheimer's disease (AD). Therefore, the identification of molecules that regulate Aβ generation is crucial for future therapeutic approaches for AD. We demonstrated previously that RanBP9 regulates Aβ generation in a number of cell lines and primary neuronal cultures by forming tripartite protein complexes with APP, low-density lipoprotein-related protein, and BACE1, consequently leading to increased amyloid plaque burden in the brain. RanBP9 is a scaffold protein that exists and functions in multiprotein complexes. To identify other proteins that may bind RanBP9 and regulate Aβ levels, we used a two-hybrid analysis against a human brain cDNA library and identified COPS5 as a novel RanBP9-interacting protein. This interaction was confirmed by coimmunoprecipitation experiments in both neuronal and non-neuronal cells and mouse brain. Colocalization of COPS5 and RanBP9 in the same subcellular compartments further supported the interaction of both proteins. Furthermore, like RanBP9, COPS5 robustly increased Aβ generation, followed by increased soluble APP-β (sAPP-β) and decreased soluble-APP-α (sAPP-α) levels. Most importantly, down-regulation of COPS5 by siRNAs reduced Aβ generation, implying that endogenous COPS5 regulates Aβ generation. Finally, COPS5 levels were increased significantly in AD brains and APΔE9 transgenic mice, and overexpression of COPS5 strongly increased RanBP9 protein levels by increasing its half-life. Taken together, these results suggest that COPS5 increases Aβ generation by increasing RanBP9 levels. Thus, COPS5 is a novel RanBP9-binding protein that increases APP processing and Aβ generation by stabilizing RanBP9 protein levels.
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RanBP9 aggravates synaptic damage in the mouse brain and is inversely correlated to spinophilin levels in Alzheimer's brain synaptosomes. Cell Death Dis 2013; 4:e667. [PMID: 23764848 PMCID: PMC3698550 DOI: 10.1038/cddis.2013.183] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
We previously demonstrated that overexpression of RanBP9 led to enhanced Aβ generation in a variety of cell lines and primary neuronal cultures, and subsequently, we confirmed increased amyloid plaque burden in a mouse model of Alzheimer's disease (AD). In the present study, we found striking reduction of spinophilin protein levels when RanBP9 is overexpressed. At 12 months of age, we found spinophilin levels reduced by 70% (P<0.001) in the cortex of APΔE9/RanBP9 mice compared with that in wild-type (WT) controls. In the hippocampus, the spinophilin levels were reduced by 45% (P<0.01) in the APΔE9/RanBP9 mice. Spinophilin immunoreactivity was also reduced by 22% (P<0.01) and 12% (P<0.05) in the cortex of APΔE9/RanBP9 and APΔE9 mice, respectively. In the hippocampus, the reductions were 27% (P<0.001) and 14% (P<0.001) in the APΔE9/RanBP9 and APΔE9 mice, respectively. However, in the cerebellum, spinophilin levels were not altered in either APΔE9 or APΔE9/RanBP9 mice. Additionally, synaptosomal functional integrity was reduced under basal conditions by 39% (P<0.001) in the APΔE9/RanBP9 mice and ∼23% (P<0.001) in the APΔE9 mice compared with that in WT controls. Under ATP- and KCl-stimulated conditions, we observed higher mitochondrial activity in the WT and APΔE9 mice, but lower in the APΔE9/RanBP9 mice. Significantly, we confirmed the inverse relationship between RanBP9-N60 and spinophilin in the synaptosomes of Alzheimer's brains. More importantly, both APΔE9 and APΔE9/RanBP9 mice showed impaired learning and memory skills compared to WT controls. These data suggest that RanBP9 might play a crucial role in the loss of spines and synapses in AD.
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25
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Martiskainen H, Haapasalo A, Kurkinen KMA, Pihlajamäki J, Soininen H, Hiltunen M. Targeting ApoE4/ApoE receptor LRP1 in Alzheimer's disease. Expert Opin Ther Targets 2013; 17:781-94. [PMID: 23573918 DOI: 10.1517/14728222.2013.789862] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Progressive neuronal loss is a key feature in Alzheimer's disease (AD), which is the most common neurodegenerative disorder in the aging population. Currently, there are no therapeutic means to intervene neuronal damage in AD and therefore innovative approaches to discover novel strategies for the treatment of AD are needed. Based on the prevailing amyloid cascade hypothesis, it is conceivable that lowering the β-amyloid (Aβ) levels is sufficient to slow down the disease process, if started early enough. AREAS COVERED Here, we review genetic and biological functions related to apolipoprotein E (ApoE) and low-density lipoprotein receptor-related protein 1 receptor (LRP1)-mediated clearance of Aβ. Furthermore, we discuss the AD-related therapeutic potential of targeting to ApoE receptor LRP1 at the blood-brain barrier (BBB) and in the periphery. EXPERT OPINION Due to the recent setbacks in the clinical trials targeting AD, it is instrumental to seek alternative therapeutic approaches, which aim to reduce the accumulation of Aβ in the brain tissue. As the ApoE/LRP1-mediated clearance of Aβ across the BBB is the key event in the regulation of Aβ transcytosis from brain to periphery, direct targeting of this protein entity at the BBB holds a great potential in the treatment of AD.
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Affiliation(s)
- Henna Martiskainen
- Kuopio University Hospital, Institute of Clinical Medicine-Neurology, University of Eastern Finland and Department of Neurology, Kuopio, Finland
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Liu T, Roh SE, Woo JA, Ryu H, Kang DE. Cooperative role of RanBP9 and P73 in mitochondria-mediated apoptosis. Cell Death Dis 2013; 4:e476. [PMID: 23348590 PMCID: PMC3563991 DOI: 10.1038/cddis.2012.203] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mitochondrial dysfunction and synaptic damage are critical early features of Alzheimer's disease (AD) associated with amyloid β (Aβ) and τ. We previously reported that the scaffolding protein RanBP9, which is overall increased in AD, simultaneously promotes Aβ generation and focal adhesion disruption by accelerating the endocytosis of APP and β1-integrin, respectively. Moreover, RanBP9 induces neurodegeneration in vitro and in vivo and mediates Aβ-induced neurotoxicity. However, little is known regarding the mechanisms underlying such neurotoxic processes. Here, we show that RanBP9 induces the loss of mitochondrial membrane potential and increase in mitochondrial superoxides associated with decrease in Bcl-2, increase in Bax protein and oligomerization, fragmentation of mitochondria, and cytochrome c release. RanBP9-induced neurotoxic changes are significantly prevented by the mitochondrial fission inhibitor Mdivi-1 and by classical inhibitors of the mitochondrial apoptosis, XIAP, Bcl-2, and Bcl-xl. RanBP9 physically interacts with the tumor suppressor p73 and increases endogenous p73α levels at both transcriptional and post-translational levels;moreover, the knockdown of endogenous p73 by siRNA effectively blocks RanBP9 and Aβ1-42-induced mitochondria-mediated cell death. Conversely, siRNA knockdown of endogenous RanBP9 also suppresses p73-induced apoptosis, suggesting that RanBP9 and p73 have cooperative roles in inducing cell death. Taken together, these finding implicate the RanBP9/p73 complex in mitochondria-mediated apoptosis in addition to its role in enhancing Aβ generation.
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Affiliation(s)
- T Liu
- WCU-Neurocytomics Program, Seoul National University College of Medicine, Seoul, Korea
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27
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Esteves SLC, Korrodi-Gregório L, Cotrim CZ, van Kleeff PJM, Domingues SC, da Cruz e Silva OAB, Fardilha M, da Cruz e Silva EF. Protein phosphatase 1γ isoforms linked interactions in the brain. J Mol Neurosci 2012; 50:179-97. [PMID: 23080069 DOI: 10.1007/s12031-012-9902-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 10/03/2012] [Indexed: 01/03/2023]
Abstract
Posttranslational protein modifications, in particular reversible protein phosphorylation, are important regulatory mechanisms involved in cellular signaling transduction pathways. Thousands of human proteins are phosphorylatable and the tight regulation of phosphorylation states is crucial for cell maintenance and development. Protein phosphorylation occurs primarily on serine, threonine, and tyrosine residues, through the antagonistic actions of protein kinases and phosphatases. The catalytic subunit of protein phosphatase 1 (PP1), a major Ser/Thr-phosphatase, associates with a large variety of regulatory subunits that define substrate specificity and determine specific cellular pathway responses. PP1 has been shown to bind to different proteins in the brain in order to execute key and differential functions. This work reports the identification of proteins expressed in the human brain that interact with PP1γ1 and PP1γ2 isoforms by the yeast two-hybrid method. An extensive search of PP1-binding motifs was performed for the proteins identified, revealing already known PP1 regulators but also novel interactors. Moreover, our results were integrated with the data of PP1γ interacting proteins from several public web databases, permitting the development of physical maps of the novel interactions. The PP1γ interactome thus obtained allowed for the identification of novel PP1 interacting proteins, supporting novel functions of PP1γ isoforms in the human brain.
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Affiliation(s)
- Sara L C Esteves
- Signal Transduction Laboratory, Centre for Cell Biology, Biology Department, University of Aveiro, 3810-193 Aveiro, Portugal
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Pivotal role of the RanBP9-cofilin pathway in Aβ-induced apoptosis and neurodegeneration. Cell Death Differ 2012; 19:1413-23. [PMID: 22361682 DOI: 10.1038/cdd.2012.14] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Neurodegeneration associated with amyloid β (Aβ) peptide accumulation, synaptic loss, neuroinflammation, tauopathy, and memory impairments encompass the pathophysiological features of Alzheimer's disease (AD). We previously reported that the scaffolding protein RanBP9, which is overall increased in brains of AD patients, simultaneously promotes Aβ generation and focal adhesion disruption by accelerating the endocytosis of amyloid precursor protein (APP) and β1-integrin, respectively. Here, we show that RanBP9 protein levels are increased by fourfold in FAD mutant APP transgenic mice. Accordingly, RanBP9 transgenic mice demonstrate significantly increased synapse loss, neurodegeneration, gliosis, and spatial memory deficits. RanBP9 overexpression promotes apoptosis and potentiates Aβ-induced neurotoxicity independent of its capacity to promote Aβ generation. Conversely, RanBP9 reduction by siRNA or gene dosage mitigates Aβ-induced neurotoxicity. Importantly, RanBP9 activates/dephosphorylates cofilin, a key regulator of actin dynamics and mitochondria-mediated apoptosis, and siRNA knockdown of cofilin abolishes both Aβ and RanBP9-induced apoptosis. These findings implicate the RanBP9-cofilin pathway as critical therapeutic targets not only for stemming Aβ generation but also antagonizing Aβ-induced neurotoxicity.
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