1
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Pandey RS, Kotredes KP, Sasner M, Howell GR, Carter GW. Differential splicing of neuronal genes in a Trem2*R47H mouse model mimics alterations associated with Alzheimer's disease. BMC Genomics 2023; 24:172. [PMID: 37016304 PMCID: PMC10074678 DOI: 10.1186/s12864-023-09280-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 03/29/2023] [Indexed: 04/06/2023] Open
Abstract
BACKGROUND Molecular characterization of late-onset Alzheimer's disease (LOAD), the leading cause of age-related dementia, has revealed transcripts, proteins, and pathway alterations associated with disease. Assessing these postmortem signatures of LOAD in experimental model systems can further elucidate their relevance to disease origins and progression. Model organisms engineered with human genetic factors further link these signatures to disease-associated variants, especially when studies are designed to leverage homology across species. Here we assess differential gene splicing patterns in aging mouse models carrying humanized APOE4 and/or the Trem2*R47H variant on a C57BL/6J background. We performed a differential expression of gene (DEG) and differential splicing analyses on whole brain transcriptomes at multiple ages. To better understand the difference between differentially expressed and differentially spliced genes, we evaluated enrichment of KEGG pathways and cell-type specific gene signatures of the adult brain from each alteration type. To determine LOAD relevance, we compared differential splicing results from mouse models with multiple human AD splicing studies. RESULTS We found that differentially expressed genes in Trem2*R47H mice were significantly enriched in multiple AD-related pathways, including immune response, osteoclast differentiation, and metabolism, whereas differentially spliced genes were enriched for neuronal related functions, including GABAergic synapse and glutamatergic synapse. These results were reinforced by the enrichment of microglial genes in DEGs and neuronal genes in differentially spliced genes in Trem2*R47H mice. We observed significant overlap between differentially spliced genes in Trem2*R47H mice and brains from human AD subjects. These effects were absent in APOE4 mice and suppressed in APOE4.Trem2*R47H double mutant mice relative to Trem2*R47H mice. CONCLUSIONS The cross-species observation that alternative splicing observed in LOAD are present in Trem2*R47H mouse models suggests a novel link between this candidate risk gene and molecular signatures of LOAD in neurons and demonstrates how deep molecular analysis of new genetic models links molecular disease outcomes to a human candidate gene.
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Affiliation(s)
- Ravi S Pandey
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT, 06032, USA
| | - Kevin P Kotredes
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA
| | - Michael Sasner
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA
| | - Gareth R Howell
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA
| | - Gregory W Carter
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT, 06032, USA.
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA.
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2
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Chami M, Checler F. Targeting Post-Translational Remodeling of Ryanodine Receptor: A New Track for Alzheimer's Disease Therapy? Curr Alzheimer Res 2021; 17:313-323. [PMID: 32096743 DOI: 10.2174/1567205017666200225102941] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 01/08/2020] [Accepted: 02/24/2020] [Indexed: 01/20/2023]
Abstract
Pathologic calcium (Ca2+) signaling linked to Alzheimer's Disease (AD) involves the intracellular Ca2+ release channels/ryanodine receptors (RyRs). RyRs are macromolecular complexes where the protein-protein interactions between RyRs and several regulatory proteins impact the channel function. Pharmacological and genetic approaches link the destabilization of RyRs macromolecular complexes to several human pathologies including brain disorders. In this review, we discuss our recent data, which demonstrated that enhanced neuronal RyR2-mediated Ca2+ leak in AD is associated with posttranslational modifications (hyperphosphorylation, oxidation, and nitrosylation) leading to RyR2 macromolecular complex remodeling, and dissociation of the stabilizing protein Calstabin2 from the channel. We describe RyR macromolecular complex structure and discuss the molecular mechanisms and signaling cascade underlying neuronal RyR2 remodeling in AD. We provide evidence linking RyR2 dysfunction with β-adrenergic signaling cascade that is altered in AD. RyR2 remodeling in AD leads to histopathological lesions, alteration of synaptic plasticity, learning and memory deficits. Targeting RyR macromolecular complex remodeling should be considered as a new therapeutic window to treat/or prevent AD setting and/or progression.
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Affiliation(s)
- Mounia Chami
- Université de Nice Sophia Antipolis, IPMC, Sophia Antipolis, F-06560, France.,CNRS, IPMC, Sophia Antipolis, F-06560, France
| | - Frédéric Checler
- Université de Nice Sophia Antipolis, IPMC, Sophia Antipolis, F-06560, France.,CNRS, IPMC, Sophia Antipolis, F-06560, France
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3
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Wang H, Muthu Karuppan MK, Nair M, Lakshmana MK. Autophagy-Dependent Increased ADAM10 Mature Protein Induced by TFEB Overexpression Is Mediated Through PPARα. Mol Neurobiol 2021; 58:2269-2283. [PMID: 33417226 DOI: 10.1007/s12035-020-02230-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 11/24/2020] [Indexed: 10/22/2022]
Abstract
Nonamyloidogenic processing of amyloid precursor protein (APP) by augmenting ADAM10 is a promising therapeutic strategy for Alzheimer's disease (AD). Therefore identification of molecular pathways that regulate ADAM10 expression is crucial. Autophagy is strongly dysregulated in AD, and TFEB was recently shown to be a master regulator of autophagy-lysosome pathway (ALP). Here, we report that TFEB expression in HeLa cells increased ADAM10 mature form by 72% (p < 0.01, n = 4), while TFEB knockdown by CRISPR strategy reduced ADAM10 mature form by 36% (p < 0.05, n = 4). Autophagy inhibition by 3-methyladenine (3-MA), but not bafilomycin A1 (BAF1), reduced ADAM10 mature form by 49% (p < 0.05, n = 4) in the TFEB expressing HeLa cells. Autophagy activation by 3 h of starvation increased ADAM10 to 91% (p < 0.001, n = 6) relative to 51% (p < 0.01, n = 6) in the nutrient-fed cells. Further, siRNAs targeted against PPARα in HeLa cells decreased ADAM10 levels by 28% (p < 0.05, n = 6) relative to the cells treated with scrambled siRNAs. Further, incubation of EGFP-TFEB expressing HeLa cells with PPARα antagonist, but not PPARβ or PPARγ antagonists, prevented TFEB-induced increase in ADAM10 levels. Importantly, flag-TFEB expression in the brain also increased ADAM10 by 60% (p < 0.05, n = 3) in the cortical and 34% (p < 0.001, n = 3) in the hippocampal homogenates. ADAM10 activity also increased by 57% (p < 0.01, n = 3) in the HeLa cells. Finally, TFEB-induced ADAM10 potentiation led to increased secretion of sAPPα by 154% (p < 0.001, n = 3) in the cortex and 62% (p < 0.001, n = 3) in the hippocampus. Thus, TFEB expression enhances nonamyloidogenic processing of APP. In conclusion, TFEB expression induces ADAM10 in an autophagy-dependent manner through PPARα.
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Affiliation(s)
- Hongjie Wang
- Institute for Human Health & Disease Intervention (I-HEALTH), Department of Chemistry and Biochemistry, Center for Molecular Biology and Biotechnology, Florida Atlantic University, 5353 Parkside Drive, Jupiter, FL, 33458, USA
| | - Mohan Kumar Muthu Karuppan
- Department of Immunology and Nano-Medicine, Herbert Wertheim College of Medicine, Florida International University, 11200, 8th Street, University Park, Miami, FL, 33199, USA
| | - Madhavan Nair
- Department of Immunology and Nano-Medicine, Herbert Wertheim College of Medicine, Florida International University, 11200, 8th Street, University Park, Miami, FL, 33199, USA
| | - Madepalli K Lakshmana
- Department of Immunology and Nano-Medicine, Herbert Wertheim College of Medicine, Florida International University, 11200, 8th Street, University Park, Miami, FL, 33199, USA.
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4
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Chami M, Checler F. Alterations of the Endoplasmic Reticulum (ER) Calcium Signaling Molecular Components in Alzheimer's Disease. Cells 2020; 9:cells9122577. [PMID: 33271984 PMCID: PMC7760721 DOI: 10.3390/cells9122577] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/18/2020] [Accepted: 11/30/2020] [Indexed: 02/07/2023] Open
Abstract
Sustained imbalance in intracellular calcium (Ca2+) entry and clearance alters cellular integrity, ultimately leading to cellular homeostasis disequilibrium and cell death. Alzheimer’s disease (AD) is the most common cause of dementia. Beside the major pathological features associated with AD-linked toxic amyloid beta (Aβ) and hyperphosphorylated tau (p-tau), several studies suggested the contribution of altered Ca2+ handling in AD development. These studies documented physical or functional interactions of Aβ with several Ca2+ handling proteins located either at the plasma membrane or in intracellular organelles including the endoplasmic reticulum (ER), considered the major intracellular Ca2+ pool. In this review, we describe the cellular components of ER Ca2+ dysregulations likely responsible for AD. These include alterations of the inositol 1,4,5-trisphosphate receptors’ (IP3Rs) and ryanodine receptors’ (RyRs) expression and function, dysfunction of the sarco-endoplasmic reticulum Ca2+ ATPase (SERCA) activity and upregulation of its truncated isoform (S1T), as well as presenilin (PS1, PS2)-mediated ER Ca2+ leak/ER Ca2+ release potentiation. Finally, we highlight the functional consequences of alterations of these ER Ca2+ components in AD pathology and unravel the potential benefit of targeting ER Ca2+ homeostasis as a tool to alleviate AD pathogenesis.
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Affiliation(s)
- Mounia Chami
- Correspondence: ; Tel.: +33-4939-53457; Fax: +33-4939-53408
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5
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Ahmad F, Liu P. Synaptosome as a tool in Alzheimer's disease research. Brain Res 2020; 1746:147009. [PMID: 32659233 DOI: 10.1016/j.brainres.2020.147009] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/21/2020] [Accepted: 07/04/2020] [Indexed: 12/29/2022]
Abstract
Synapse dysfunction is an integral feature of Alzheimer's disease (AD) pathophysiology. In fact, prodromal manifestation of structural and functional deficits in synapses much prior to appearance of overt pathological hallmarks of the disease indicates that AD might be considered as a degenerative disorder of the synapses. Several research instruments and techniques have allowed us to study synaptic function and plasticity and their alterations in pathological conditions, such as AD. One such tool is the biochemically isolated preparations of detached and resealed synaptic terminals, the "synaptosomes". Because of the preservation of many of the physiological processes such as metabolic and enzymatic activities, synaptosomes have proved to be an indispensable ex vivo model system to study synapse physiology both when isolated from fresh or cryopreserved tissues, and from animal or human post-mortem tissues. This model system has been tremendously successful in the case of post-mortem tissues because of their accessibility relative to acute brain slices or cultures. The current review details the use of synaptosomes in AD research and its potential as a valuable tool in furthering our understanding of the pathogenesis and in devising and testing of therapeutic strategies for the disease.
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Affiliation(s)
- Faraz Ahmad
- Department of Anatomy, School of Biomedical Sciences, Brain Research New Zealand, University of Otago, Dunedin, New Zealand.
| | - Ping Liu
- Department of Anatomy, School of Biomedical Sciences, Brain Research New Zealand, University of Otago, Dunedin, New Zealand
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6
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Tessari A, Soliman SHA, Orlacchio A, Capece M, Amann JM, Visone R, Carbone DP, Palmieri D, Coppola V. RANBP9 as potential therapeutic target in non-small cell lung cancer. JOURNAL OF CANCER METASTASIS AND TREATMENT 2020; 6. [PMID: 34778565 PMCID: PMC8589326 DOI: 10.20517/2394-4722.2020.32] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related deaths in the Western world. Despite progress made with targeted therapies and immune checkpoint inhibitors, the vast majority of patients have to undergo chemotherapy with platinum-based drugs. To increase efficacy and reduce potential side effects, a more comprehensive understanding of the mechanisms of the DNA damage response (DDR) is required. We have shown that overexpressby live cell imaging (Incuyion of the scaffold protein RAN binding protein 9 (RANBP9) is pervasive in NSCLC. More importantly, patients with higher levels of RANBP9 exhibit a worse outcome from treatment with platinum-based drugs. Mechanistically, RANBP9 exists as a target and an enabler of the ataxia telangiectasia mutated (ATM) kinase signaling. Indeed, the depletion of RANBP9 in NSCLC cells abates ATM activation and its downstream targets such as pby live cell imaging (Incuy53 signaling. RANBP9 knockout cells are more sensitive than controls to the inhibition of the ataxia and telangiectasia-related (ATR) kinase but not to ATM inhibition. The absence of RANBP9 renders cells more sensitive to drugs inhibiting the Poly(ADP-ribose)-Polymerase (PARP) resulting in a "BRCAness-like" phenotype. In summary, as a result of increased sensitivity to DNA damaging drugs conferred by its ablation in vitro and in vivo, RANBP9 may be considered as a potential target for the treatment of NSCLC. This article aims to report the results from past and ongoing investigations focused on the role of RANBP9 in the response to DNA damage, particularly in the context of NSCLC. This review concludes with future directions and speculative remarks which will need to be addressed in the coming years.
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Affiliation(s)
- Anna Tessari
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University and Arthur G. James Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Shimaa H A Soliman
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University and Arthur G. James Comprehensive Cancer Center, Columbus, OH 43210, USA.,Department of Medicine, Dentistry and Biotechnology, G. d'Annunzio University of Chieti, Chieti 66100, Italy.,Current address: Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Arturo Orlacchio
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University and Arthur G. James Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Marina Capece
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University and Arthur G. James Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Joseph M Amann
- Current address: Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Rosa Visone
- Department of Medicine, Dentistry and Biotechnology, G. d'Annunzio University of Chieti, Chieti 66100, Italy
| | - David P Carbone
- Division of Medical Oncology, Department of Internal Medicine, College of Medicine, The Ohio State University and Arthur G. James Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Dario Palmieri
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University and Arthur G. James Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Vincenzo Coppola
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University and Arthur G. James Comprehensive Cancer Center, Columbus, OH 43210, USA
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7
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Meng X, McGraw CM, Wang W, Jing J, Yeh SY, Wang L, Lopez J, Brown AM, Lin T, Chen W, Xue M, Sillitoe RV, Jiang X, Zoghbi HY. Neurexophilin4 is a selectively expressed α-neurexin ligand that modulates specific cerebellar synapses and motor functions. eLife 2019; 8:e46773. [PMID: 31524598 PMCID: PMC6763262 DOI: 10.7554/elife.46773] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 09/13/2019] [Indexed: 01/03/2023] Open
Abstract
Neurexophilins are secreted neuropeptide-like glycoproteins, and neurexophilin1 and neurexophilin3 are ligands for the presynaptic cell adhesion molecule α-neurexin. Neurexophilins are more selectively expressed in the brain than α-neurexins, however, which led us to ask whether neurexophilins modulate the function of α-neurexin in a context-specific manner. We characterized the expression and function of neurexophilin4 in mice and found it to be expressed in subsets of neurons responsible for feeding, emotion, balance, and movement. Deletion of Neurexophilin4 caused corresponding impairments, most notably in motor learning and coordination. We demonstrated that neurexophilin4 interacts with α-neurexin and GABAARs in the cerebellum. Loss of Neurexophilin4 impaired cerebellar Golgi-granule inhibitory neurotransmission and synapse number, providing a partial explanation for the motor learning and coordination deficits observed in the Neurexophilin4 null mice. Our data illustrate how selectively expressed Neurexophilin4, an α-neurexin ligand, regulates specific synapse function and modulates cerebellar motor control.
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Affiliation(s)
- Xiangling Meng
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | - Christopher M McGraw
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
| | - Wei Wang
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Junzhan Jing
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | - Szu-Ying Yeh
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
| | - Li Wang
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Joanna Lopez
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Amanda M Brown
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Department of Pathology and ImmunologyBaylor College of MedicineHoustonUnited States
| | - Tao Lin
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Department of Pathology and ImmunologyBaylor College of MedicineHoustonUnited States
| | - Wu Chen
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- The Cain Foundation LaboratoriesJan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | - Mingshan Xue
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- The Cain Foundation LaboratoriesJan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | - Roy V Sillitoe
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of Pathology and ImmunologyBaylor College of MedicineHoustonUnited States
| | - Xiaolong Jiang
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
| | - Huda Y Zoghbi
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s HospitalHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Howard Hughes Medical Institute, Baylor College of MedicineHoustonUnited States
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8
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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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9
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Tau Protein Squired by Molecular Chaperones During Alzheimer’s Disease. J Mol Neurosci 2018; 66:356-368. [DOI: 10.1007/s12031-018-1174-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 09/14/2018] [Indexed: 01/19/2023]
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10
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Lampert F, Stafa D, Goga A, Soste MV, Gilberto S, Olieric N, Picotti P, Stoffel M, Peter M. The multi-subunit GID/CTLH E3 ubiquitin ligase promotes cell proliferation and targets the transcription factor Hbp1 for degradation. eLife 2018; 7:35528. [PMID: 29911972 PMCID: PMC6037477 DOI: 10.7554/elife.35528] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 06/16/2018] [Indexed: 12/17/2022] Open
Abstract
In yeast, the glucose-induced degradation-deficient (GID) E3 ligase selectively degrades superfluous gluconeogenic enzymes. Here, we identified all subunits of the mammalian GID/CTLH complex and provide a comprehensive map of its hierarchical organization and step-wise assembly. Biochemical reconstitution demonstrates that the mammalian complex possesses inherent E3 ubiquitin ligase activity, using Ube2H as its cognate E2. Deletions of multiple GID subunits compromise cell proliferation, and this defect is accompanied by deregulation of critical cell cycle markers such as the retinoblastoma (Rb) tumor suppressor, phospho-Histone H3 and Cyclin A. We identify the negative regulator of pro-proliferative genes Hbp1 as a bonafide GID/CTLH proteolytic substrate. Indeed, Hbp1 accumulates in cells lacking GID/CTLH activity, and Hbp1 physically interacts and is ubiquitinated in vitro by reconstituted GID/CTLH complexes. Our biochemical and cellular analysis thus demonstrates that the GID/CTLH complex prevents cell cycle exit in G1, at least in part by degrading Hbp1.
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Affiliation(s)
| | - Diana Stafa
- Institute of Biochemistry, ETH Zürich, Zürich, Switzerland
| | - Algera Goga
- Institute of Molecular Health Sciences, ETH Zürich, Zürich, Switzerland
| | | | | | - Natacha Olieric
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Paola Picotti
- Institute of Biochemistry, ETH Zürich, Zürich, Switzerland
| | - Markus Stoffel
- Institute of Molecular Health Sciences, ETH Zürich, Zürich, Switzerland
| | - Matthias Peter
- Institute of Biochemistry, ETH Zürich, Zürich, Switzerland
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11
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Characterisation of spinophilin immunoreactivity in postmortem human brain homogenates. Prog Neuropsychopharmacol Biol Psychiatry 2018; 81:236-242. [PMID: 28941770 DOI: 10.1016/j.pnpbp.2017.09.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 09/14/2017] [Accepted: 09/19/2017] [Indexed: 11/23/2022]
Abstract
Spinophilin is a multifunctional scaffold protein that regulates the formation and function of dendritic spines and plays a role in neuronal migration. The distinct roles of spinophilin depend on its localization and the direct interaction with other proteins, which may target spinophilin to specific locations within the cell. Several studies suggest a role of spinophilin in the pathophysiology of neurological or psychiatric diseases. However, the majority have been performed in animals or cultured cells. Thus, the aim of the present study was to characterise the regional and subcellular expression of spinophilin immunoreactivity by western blot in postmortem human brain. Two specific immunoreactive bands for spinophilin were observed: an intense band migrating at around 120kDa, which seems to correspond to the apparent molecular weight of spinophilin described by other authors, and a less intense band of around 95kDa. This second form seems to be a proteolysis or cleavage product of the ~120kDa spinophilin. Interestingly, the subcellular distribution of both bands was different. In membrane fraction, the ~120kDa spinophilin band was the most abundant, whereas in cytosol it was the ~95kDa form. Furthermore, a different regional distribution for ~120kDa spinophilin band was observed, with the highest expression in prefrontal cortex, followed by hippocampus and cerebellum, and the lowest in caudate nucleus. Altogether, these results constitute a useful reference for future studies of spinophilin in pathological and non-pathological human brain tissues.
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12
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Jones EV, Bernardinelli Y, Zarruk JG, Chierzi S, Murai KK. SPARC and GluA1-Containing AMPA Receptors Promote Neuronal Health Following CNS Injury. Front Cell Neurosci 2018; 12:22. [PMID: 29449802 PMCID: PMC5799273 DOI: 10.3389/fncel.2018.00022] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 01/15/2018] [Indexed: 12/22/2022] Open
Abstract
The proper formation and maintenance of functional synapses in the central nervous system (CNS) requires communication between neurons and astrocytes and the ability of astrocytes to release neuromodulatory molecules. Previously, we described a novel role for the astrocyte-secreted matricellular protein SPARC (Secreted Protein, Acidic and Rich in Cysteine) in regulating α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) and plasticity at developing synapses. SPARC is highly expressed by astrocytes and microglia during CNS development but its level is reduced in adulthood. Interestingly, SPARC has been shown to be upregulated in CNS injury and disease. However, the role of SPARC upregulation in these contexts is not fully understood. In this study, we investigated the effect of chronic SPARC administration on glutamate receptors on mature hippocampal neuron cultures and following CNS injury. We found that SPARC treatment increased the number of GluA1-containing AMPARs at synapses and enhanced synaptic function. Furthermore, we determined that the increase in synaptic strength induced by SPARC could be inhibited by Philanthotoxin-433, a blocker of homomeric GluA1-containing AMPARs. We then investigated the effect of SPARC treatment on neuronal health in an injury context where SPARC expression is upregulated. We found that SPARC levels are increased in astrocytes and microglia following middle cerebral artery occlusion (MCAO) in vivo and oxygen-glucose deprivation (OGD) in vitro. Remarkably, chronic pre-treatment with SPARC prevented OGD-induced loss of synaptic GluA1. Furthermore, SPARC treatment reduced neuronal death through Philanthotoxin-433 sensitive GluA1 receptors. Taken together, this study suggests a novel role for SPARC and GluA1 in promoting neuronal health and recovery following CNS damage.
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Affiliation(s)
- Emma V Jones
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | | | - Juan G Zarruk
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - Sabrina Chierzi
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | - Keith K Murai
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
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13
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Lacampagne A, Liu X, Reiken S, Bussiere R, Meli AC, Lauritzen I, Teich AF, Zalk R, Saint N, Arancio O, Bauer C, Duprat F, Briggs CA, Chakroborty S, Stutzmann GE, Shelanski ML, Checler F, Chami M, Marks AR. Post-translational remodeling of ryanodine receptor induces calcium leak leading to Alzheimer's disease-like pathologies and cognitive deficits. Acta Neuropathol 2017. [PMID: 28631094 DOI: 10.1007/s00401-017-1733-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The mechanisms underlying ryanodine receptor (RyR) dysfunction associated with Alzheimer disease (AD) are still not well understood. Here, we show that neuronal RyR2 channels undergo post-translational remodeling (PKA phosphorylation, oxidation, and nitrosylation) in brains of AD patients, and in two murine models of AD (3 × Tg-AD, APP +/- /PS1 +/-). RyR2 is depleted of calstabin2 (KFBP12.6) in the channel complex, resulting in endoplasmic reticular (ER) calcium (Ca2+) leak. RyR-mediated ER Ca2+ leak activates Ca2+-dependent signaling pathways, contributing to AD pathogenesis. Pharmacological (using a novel RyR stabilizing drug Rycal) or genetic rescue of the RyR2-mediated intracellular Ca2+ leak improved synaptic plasticity, normalized behavioral and cognitive functions and reduced Aβ load. Genetically altered mice with congenitally leaky RyR2 exhibited premature and severe defects in synaptic plasticity, behavior and cognitive function. These data provide a mechanism underlying leaky RyR2 channels, which could be considered as potential AD therapeutic targets.
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14
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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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15
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Bussiere R, Lacampagne A, Reiken S, Liu X, Scheuerman V, Zalk R, Martin C, Checler F, Marks AR, Chami M. Amyloid β production is regulated by β2-adrenergic signaling-mediated post-translational modifications of the ryanodine receptor. J Biol Chem 2017; 292:10153-10168. [PMID: 28476886 PMCID: PMC5473221 DOI: 10.1074/jbc.m116.743070] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 05/02/2017] [Indexed: 11/06/2022] Open
Abstract
Alteration of ryanodine receptor (RyR)-mediated calcium (Ca2+) signaling has been reported in Alzheimer disease (AD) models. However, the molecular mechanisms underlying altered RyR-mediated intracellular Ca2+ release in AD remain to be fully elucidated. We report here that RyR2 undergoes post-translational modifications (phosphorylation, oxidation, and nitrosylation) in SH-SY5Y neuroblastoma cells expressing the β-amyloid precursor protein (βAPP) harboring the familial double Swedish mutations (APPswe). RyR2 macromolecular complex remodeling, characterized by depletion of the regulatory protein calstabin2, resulted in increased cytosolic Ca2+ levels and mitochondrial oxidative stress. We also report a functional interplay between amyloid β (Aβ), β-adrenergic signaling, and altered Ca2+ signaling via leaky RyR2 channels. Thus, post-translational modifications of RyR occur downstream of Aβ through a β2-adrenergic signaling cascade that activates PKA. RyR2 remodeling in turn enhances βAPP processing. Importantly, pharmacological stabilization of the binding of calstabin2 to RyR2 channels, which prevents Ca2+ leakage, or blocking the β2-adrenergic signaling cascade reduced βAPP processing and the production of Aβ in APPswe-expressing SH-SY5Y cells. We conclude that targeting RyR-mediated Ca2+ leakage may be a therapeutic approach to treat AD.
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Affiliation(s)
- Renaud Bussiere
- From the Université Côte d'Azur, CNRS, IPMC, France, "Labex Distalz," 660 route des Lucioles, 06560 Sophia-Antipolis, Valbonne, France
| | - Alain Lacampagne
- INSERM U1046, CNRS UMR9214, CNRS LIA1185, Université de Montpellier, CHRU Montpellier, 34295 Montpellier, France, and
| | - Steven Reiken
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Xiaoping Liu
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Valerie Scheuerman
- INSERM U1046, CNRS UMR9214, CNRS LIA1185, Université de Montpellier, CHRU Montpellier, 34295 Montpellier, France, and
| | - Ran Zalk
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Cécile Martin
- From the Université Côte d'Azur, CNRS, IPMC, France, "Labex Distalz," 660 route des Lucioles, 06560 Sophia-Antipolis, Valbonne, France
| | - Frederic Checler
- From the Université Côte d'Azur, CNRS, IPMC, France, "Labex Distalz," 660 route des Lucioles, 06560 Sophia-Antipolis, Valbonne, France
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York, New York 10032
| | - Mounia Chami
- From the Université Côte d'Azur, CNRS, IPMC, France, "Labex Distalz," 660 route des Lucioles, 06560 Sophia-Antipolis, Valbonne, France,
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16
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Wang S, Yu L, Yang H, Li C, Hui Z, Xu Y, Zhu X. Oridonin Attenuates Synaptic Loss and Cognitive Deficits in an Aβ1-42-Induced Mouse Model of Alzheimer's Disease. PLoS One 2016; 11:e0151397. [PMID: 26974541 PMCID: PMC4790895 DOI: 10.1371/journal.pone.0151397] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 02/26/2016] [Indexed: 12/31/2022] Open
Abstract
Synaptic loss induced by beta-amyloid (Aβ) plays a critical role in the pathophysiology of Alzheimer’s disease (AD), but the mechanisms underlying this process remain unknown. In this study, we found that oridonin (Ori) rescued synaptic loss induced by Aβ1–42in vivo and in vitro and attenuated the alterations in dendritic structure and spine density observed in the hippocampus of AD mice. In addition, Ori increased the expression of PSD-95 and synaptophysin and promoted mitochondrial activity in the synaptosomes of AD mice. Ori also activated the BDNF/TrkB/CREB signaling pathway in the hippocampus of AD mice. Furthermore, in the Morris water maze test, Ori reduced latency and searching distance and increased the number of platform crosses in AD mice. These data suggest that Ori might prevent synaptic loss and improve behavioral symptoms in Aβ1–42-induced AD mice.
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Affiliation(s)
- Sulei Wang
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - Linjie Yu
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, PR China
| | - Hui Yang
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - Chaosheng Li
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - Zhen Hui
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - Yun Xu
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, PR China
- Jiangsu Stroke Research Collaborative Group, Nanjing, PR China
- Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, PR China
- Jiangsu Key Laboratory for Molecular Medicine, Nanjing University Medical School, Nanjing, PR China
- * E-mail: (YX); (XLZ)
| | - Xiaolei Zhu
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, PR China
- * E-mail: (YX); (XLZ)
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17
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Niklison-Chirou MV, Killick R, Knight RA, Nicotera P, Melino G, Agostini M. How Does p73 Cause Neuronal Defects? Mol Neurobiol 2015; 53:4509-20. [PMID: 26266644 DOI: 10.1007/s12035-015-9381-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/27/2015] [Indexed: 11/25/2022]
Abstract
The p53-family member, p73, plays a key role in the development of the central nervous system (CNS), in senescence, and in tumor formation. The role of p73 in neuronal differentiation is complex and involves several downstream pathways. Indeed, in the last few years, we have learnt that TAp73 directly or indirectly regulates several genes involved in neural biology. In particular, TAp73 is involved in the maintenance of neural stem/progenitor cell self-renewal and differentiation throughout the regulation of SOX-2, Hey-2, TRIM32 and Notch. In addition, TAp73 is also implicated in the regulation of the differentiation and function of postmitotic neurons by regulating the expression of p75NTR and GLS2 (glutamine metabolism). Further still, the regulation of miR-34a by TAp73 indicates that microRNAs can also participate in this multifunctional role of p73 in adult brain physiology. However, contradictory results still exist in the relationship between p73 and brain disorders, and this remains an important area for further investigation.
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Affiliation(s)
- Maria Victoria Niklison-Chirou
- Toxicology Unit, Medical Research Council, Leicester, LE1 9HN, UK
- Blizard Institute of Cell and Molecular Science, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK
| | - Richard Killick
- The Institute of Psychiatry, Psychology and Neuroscience, King's College London, Denmark Hill, London, SE5 8AF, UK
| | - Richard A Knight
- Toxicology Unit, Medical Research Council, Leicester, LE1 9HN, UK
| | | | - Gerry Melino
- Toxicology Unit, Medical Research Council, Leicester, LE1 9HN, UK.
- Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", 00133, Rome, Italy.
| | - Massimiliano Agostini
- Toxicology Unit, Medical Research Council, Leicester, LE1 9HN, UK.
- Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", 00133, Rome, Italy.
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18
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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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19
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Choi TY, Jung S, Nah J, Ko HY, Jo SH, Chung G, Park K, Jung YK, Choi SY. Low levels of methyl β-cyclodextrin disrupt GluA1-dependent synaptic potentiation but not synaptic depression. J Neurochem 2015; 132:276-85. [PMID: 25418874 DOI: 10.1111/jnc.12995] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 10/29/2014] [Accepted: 11/06/2014] [Indexed: 01/25/2023]
Abstract
Methyl-β-cyclodextrin (MβCD) is a reagent that depletes cholesterol and disrupts lipid rafts, a type of cholesterol-enriched cell membrane microdomain. Lipid rafts are essential for neuronal functions such as synaptic transmission and plasticity, which are sensitive to even low doses of MβCD. However, how MβCD changes synaptic function, such as N-methyl-d-aspartate receptor (NMDA-R) activity, remains unclear. We monitored changes in synaptic transmission and plasticity after disrupting lipid rafts with MβCD. At low concentrations (0.5 mg/mL), MβCD decreased basal synaptic transmission and miniature excitatory post-synaptic current without changing NMDA-R-mediated synaptic transmission and the paired-pulse facilitation ratio. Interestingly, low doses of MβCD failed to deplete cholesterol or affect α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA-R) and NMDA-R levels, while clearly reducing GluA1 levels selectively in the synaptosomal fraction. Low doses of MβCD decreased the inhibitory effects of NASPM, an inhibitor for GluA2-lacking AMPA-R. MβCD successfully decreased NMDA-R-mediated long-term potentiation but did not affect the formation of either NMDA-R-mediated or group I metabotropic glutamate receptor-dependent long-term depression. MβCD inhibited de-depression without affecting de-potentiation. These results suggest that MβCD regulates GluA1-dependent synaptic potentiation but not synaptic depression in a cholesterol-independent manner.
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Affiliation(s)
- Tae-Yong Choi
- Department of Physiology and Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea
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20
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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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21
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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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22
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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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23
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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: 26] [Impact Index Per Article: 2.4] [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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