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Ameen SS, Griem-Krey N, Dufour A, Hossain MI, Hoque A, Sturgeon S, Nandurkar H, Draxler DF, Medcalf RL, Kamaruddin MA, Lucet IS, Leeming MG, Liu D, Dhillon A, Lim JP, Basheer F, Zhu HJ, Bokhari L, Roulston CL, Paradkar PN, Kleifeld O, Clarkson AN, Wellendorph P, Ciccotosto GD, Williamson NA, Ang CS, Cheng HC. N-Terminomic Changes in Neurons During Excitotoxicity Reveal Proteolytic Events Associated With Synaptic Dysfunctions and Potential Targets for Neuroprotection. Mol Cell Proteomics 2023; 22:100543. [PMID: 37030595 PMCID: PMC10199228 DOI: 10.1016/j.mcpro.2023.100543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 02/23/2023] [Accepted: 04/04/2023] [Indexed: 04/10/2023] Open
Abstract
Excitotoxicity, a neuronal death process in neurological disorders such as stroke, is initiated by the overstimulation of ionotropic glutamate receptors. Although dysregulation of proteolytic signaling networks is critical for excitotoxicity, the identity of affected proteins and mechanisms by which they induce neuronal cell death remain unclear. To address this, we used quantitative N-terminomics to identify proteins modified by proteolysis in neurons undergoing excitotoxic cell death. We found that most proteolytically processed proteins in excitotoxic neurons are likely substrates of calpains, including key synaptic regulatory proteins such as CRMP2, doublecortin-like kinase I, Src tyrosine kinase and calmodulin-dependent protein kinase IIβ (CaMKIIβ). Critically, calpain-catalyzed proteolytic processing of these proteins generates stable truncated fragments with altered activities that potentially contribute to neuronal death by perturbing synaptic organization and function. Blocking calpain-mediated proteolysis of one of these proteins, Src, protected against neuronal loss in a rat model of neurotoxicity. Extrapolation of our N-terminomic results led to the discovery that CaMKIIα, an isoform of CaMKIIβ, undergoes differential processing in mouse brains under physiological conditions and during ischemic stroke. In summary, by identifying the neuronal proteins undergoing proteolysis during excitotoxicity, our findings offer new insights into excitotoxic neuronal death mechanisms and reveal potential neuroprotective targets for neurological disorders.
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Affiliation(s)
- S Sadia Ameen
- Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, Victoria, Australia; Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Nane Griem-Krey
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Antoine Dufour
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - M Iqbal Hossain
- Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, Victoria, Australia; Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia; Department of Pharmacology and Toxicology, University of Alabama, Birmingham, Alabama, USA
| | - Ashfaqul Hoque
- St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Sharelle Sturgeon
- Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria, Australia
| | - Harshal Nandurkar
- Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria, Australia
| | - Dominik F Draxler
- Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria, Australia
| | - Robert L Medcalf
- Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria, Australia
| | - Mohd Aizuddin Kamaruddin
- Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, Victoria, Australia; Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Isabelle S Lucet
- Chemical Biology Division, The Walter and Eliza Hall Institute for Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Michael G Leeming
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Dazhi Liu
- Department of Neurology, School of Medicine, University of California, Davis, California, USA
| | - Amardeep Dhillon
- Faculty of Health, Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Deakin University, Waurn Ponds, Victoria, Australia
| | - Jet Phey Lim
- Faculty of Health, Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Deakin University, Waurn Ponds, Victoria, Australia
| | - Faiza Basheer
- Faculty of Health, Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Deakin University, Waurn Ponds, Victoria, Australia
| | - Hong-Jian Zhu
- Department of Surgery (Royal Melbourne Hospital), University of Melbourne, Parkville, Victoria, Australia
| | - Laita Bokhari
- Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, Victoria, Australia; Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Carli L Roulston
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Prasad N Paradkar
- CSIRO Health & Biosecurity, Australian Centre for Disease Preparedness, East Geelong, Victoria, Australia
| | - Oded Kleifeld
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, Haifa, Israel
| | - Andrew N Clarkson
- Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Giuseppe D Ciccotosto
- Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, Victoria, Australia; Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia.
| | - Nicholas A Williamson
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia.
| | - Ching-Seng Ang
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia.
| | - Heung-Chin Cheng
- Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, Victoria, Australia; Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia.
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Luu L, Ciccotosto GD, Cappai R. The Alzheimer's Disease Amyloid Precursor Protein and its Neuritogenic Actions. Curr Alzheimer Res 2021; 18:772-786. [PMID: 34879801 DOI: 10.2174/1567205018666211208141017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 05/09/2021] [Accepted: 06/14/2021] [Indexed: 11/22/2022]
Abstract
The Amyloid Precursor Protein (APP) is principally known and studied for its involve- ment in Alzheimer's disease as the source of the amyloid β peptide; however, its physiological ac- tions within the nervous system are also important as it is involved in a range of neuronal activi- ties, including neurogenesis, synaptic plasticity, neurite outgrowth, and neuroprotection. Of the dif- ferent neuronal functions that APP can affect, some may be relevant to APP's role in Alzheimer's disease, while others can be primarily related to its physiological roles. This review will focus on APP's neuritogenic actions and surmise the key molecular mechanisms, as well as the structural and signaling requirements, which form the basis for APP's neuritogenic effects. Deciphering the normal function(s) of APP is valuable to properly understanding its role in health as well as Alzheimer's disease.
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Affiliation(s)
- Luan Luu
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences Macquarie University, NSW 2109 . Australia
| | - Giuseppe D Ciccotosto
- Department of Pharmacology and Therapeutics, The University of Melbourne, VIC 3010. Australia
| | - Roberto Cappai
- Department of Pharmacology and Therapeutics, The University of Melbourne, VIC 3010. Australia
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3
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Inampudi C, Ciccotosto GD, Cappai R, Crack PJ. Genetic Modulators of Traumatic Brain Injury in Animal Models and the Impact of Sex-Dependent Effects. J Neurotrauma 2021; 37:706-723. [PMID: 32027210 DOI: 10.1089/neu.2019.6955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Traumatic brain injury (TBI) is a major health problem causing disability and death worldwide. There is no effective treatment, due in part to the complexity of the injury pathology and factors affecting its outcome. The extent of brain injury depends on the type of insult, age, sex, lifestyle, genetic risk factors, socioeconomic status, other co-injuries, and underlying health problems. This review discusses the genes that have been directly tested in TBI models, and whether their effects are known to be sex-dependent. Sex differences can affect the incidence, symptom onset, pathology, and clinical outcomes following injury. Adult males are more susceptible at the acute phase and females show greater injury in the chronic phase. TBI is not restricted to a single sex; despite variations in the degree of symptom onset and severity, it is important to consider both female and male animals in TBI pre-clinical research studies.
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Affiliation(s)
- Chaitanya Inampudi
- Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, Victoria, Australia
| | - Giuseppe D Ciccotosto
- Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, Victoria, Australia
| | - Roberto Cappai
- Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, Victoria, Australia
| | - Peter J Crack
- Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, Victoria, Australia
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4
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Hoque A, Williamson NA, Ameen SS, Ciccotosto GD, Hossain MI, Oakhill JS, Ng DCH, Ang CS, Cheng HC. Quantitative proteomic analyses of dynamic signalling events in cortical neurons undergoing excitotoxic cell death. Cell Death Dis 2019; 10:213. [PMID: 30824683 PMCID: PMC6397184 DOI: 10.1038/s41419-019-1445-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 01/20/2019] [Accepted: 02/01/2019] [Indexed: 12/23/2022]
Abstract
Excitotoxicity, caused by overstimulation or dysregulation of ionotropic glutamate receptors (iGluRs), is a pathological process directing neuronal death in many neurological disorders. The aberrantly stimulated iGluRs direct massive influx of calcium ions into the affected neurons, leading to changes in expression and phosphorylation of specific proteins to modulate their functions and direct their participation in the signalling pathways that induce excitotoxic neuronal death. To define these pathways, we used quantitative proteomic approaches to identify these neuronal proteins (referred to as the changed proteins) and determine how their expression and/or phosphorylation dynamically changed in association with excitotoxic cell death. Our data, available in ProteomeXchange with identifier PXD008353, identified over 100 changed proteins exhibiting significant alterations in abundance and/or phosphorylation levels at different time points (5–240 min) in neurons after glutamate overstimulation. Bioinformatic analyses predicted that many of them are components of signalling networks directing defective neuronal morphology and functions. Among them, the well-known neuronal survival regulators including mitogen-activated protein kinases Erk1/2, glycogen synthase kinase 3 (GSK3) and microtubule-associated protein (Tau), were selected for validation by biochemical approaches, which confirmed the findings of the proteomic analysis. Bioinformatic analysis predicted Protein Kinase B (Akt), c-Jun kinase (JNK), cyclin-dependent protein kinase 5 (Cdk5), MAP kinase kinase (MEK), Casein kinase 2 (CK2), Rho-activated protein kinase (Rock) and Serum/glucocorticoid-regulated kinase 1 (SGK1) as the potential upstream kinases phosphorylating some of the changed proteins. Further biochemical investigation confirmed the predictions of sustained changes of the activation states of neuronal Akt and CK2 in excitotoxicity. Thus, future investigation to define the signalling pathways directing the dynamic alterations in abundance and phosphorylation of the identified changed neuronal proteins will help elucidate the molecular mechanism of neuronal death in excitotoxicity.
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Affiliation(s)
- Ashfaqul Hoque
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Cell Signalling Research Laboratories, University of Melbourne, Parkville, VIC, 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia.,Metabolic Signalling Laboratory, St. Vincent's Institute for Medical Research, University of Melbourne, Fitzroy, VIC, 3065, Australia
| | - Nicholas A Williamson
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - S Sadia Ameen
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Cell Signalling Research Laboratories, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Giuseppe D Ciccotosto
- Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, VIC, 3010, Australia
| | - M Iqbal Hossain
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Jonathan S Oakhill
- Metabolic Signalling Laboratory, St. Vincent's Institute for Medical Research, University of Melbourne, Fitzroy, VIC, 3065, Australia.,Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria, 3000, Australia
| | - Dominic C H Ng
- School of Biomedical Sciences, University of Queensland, St. Lucia, QLD, Australia
| | - Ching-Seng Ang
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia.
| | - Heung-Chin Cheng
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia. .,Cell Signalling Research Laboratories, University of Melbourne, Parkville, VIC, 3010, Australia. .,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia.
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5
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Dai C, Xiao X, Li J, Ciccotosto GD, Cappai R, Tang S, Schneider-Futschik EK, Hoyer D, Velkov T, Shen J. Molecular Mechanisms of Neurotoxicity Induced by Polymyxins and Chemoprevention. ACS Chem Neurosci 2019; 10:120-131. [PMID: 30362702 DOI: 10.1021/acschemneuro.8b00300] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Neurotoxicity is one major unwanted side-effects associated with polymyxin (i.e., colistin and polymyxin B) therapy. Clinically, colistin neurotoxicity is characterized by neurological symptoms including dizziness, visual disturbances, vertigo, confusion, hallucinations, seizures, ataxia, and facial and peripheral paresthesias. Pathologically, colistin-induced neurotoxicity is characterized by cell injury and death in neuronal cell. This Review covers our current understanding of polymyxin-induced neurotoxicity, its underlying mechanisms, and the discovery of novel neuroprotective agents to limit this neurotoxicity. In recent years, an increasing body of literature supports the notion that polymyxin-induced nerve damage is largely related to oxidative stress and mitochondrial dysfunction. P53, PI3K/Akt, and MAPK pathways are also involved in colistin-induced neuronal cell death. The activation of the redox homeostasis pathways such as Nrf2/HO-1 and autophagy have also been shown to play protective roles against polymyxin-induced neurotoxicity. These pathways have been demonstrated to be upregulated by neuroprotective agents including curcumin, rapamycin and minocycline. Further research is needed toward the development of novel polymyxin formulations in combination with neuroprotective agents to ameliorate this unwanted adverse effect during polymyxins therapy in patients.
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Affiliation(s)
- Chongshan Dai
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, No. 2 Yuanmingyuan West Road, Beijing 100193, P. R. China
| | - Xilong Xiao
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, No. 2 Yuanmingyuan West Road, Beijing 100193, P. R. China
| | - Jichang Li
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Northeast Agricultural University, Harbin 150000, P. R. China
| | - Giuseppe D. Ciccotosto
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Roberto Cappai
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Shusheng Tang
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, No. 2 Yuanmingyuan West Road, Beijing 100193, P. R. China
| | - Elena K. Schneider-Futschik
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Daniel Hoyer
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, Victoria 3052, Australia
- Department of Molecular Medicine, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037, United States
| | - Tony Velkov
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Northeast Agricultural University, Harbin 150000, P. R. China
| | - Jianzhong Shen
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, No. 2 Yuanmingyuan West Road, Beijing 100193, P. R. China
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Abstract
Although methyl CpG binding domain protein-2 (MeCP2) is commonly understood to function as a silencing factor at methylated DNA sequences, recent studies also show that MeCP2 can bind unmethylated sequences and coordinate gene activation. MeCP2 displays broad binding patterns throughout the genome, with high expression levels similar to histone H1 in neurons. Despite its significant presence in the brain, only subtle gene expression changes occur in the absence of MeCP2. This may reflect a more complex regulatory mechanism of MeCP2 to complement chromatin binding. Using an RNA immunoprecipitation of native chromatin technique, we identify MeCP2 interacting microRNAs in mouse primary cortical neurons. In addition, comparison with mRNA sequencing data from Mecp2-null mice suggests that differentially expressed genes may indeed be targeted by MeCP2-interacting microRNAs. These findings highlight the MeCP2 interaction with microRNAs that may modulate its binding with chromatin and regulate gene expression.
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Affiliation(s)
- Abdul Waheed Khan
- a Central Clinical School, Faculty of Medicine , Monash University , Victoria , Australia.,b Baker IDI Heart and Diabetes Institute , The Alfred Medical Research and Education Precinct , Melbourne , Victoria 3004 , Australia.,c Department of Pathology , The University of Melbourne , Parkville , Victoria , Australia
| | - Mark Ziemann
- a Central Clinical School, Faculty of Medicine , Monash University , Victoria , Australia.,b Baker IDI Heart and Diabetes Institute , The Alfred Medical Research and Education Precinct , Melbourne , Victoria 3004 , Australia
| | - Haloom Rafehi
- a Central Clinical School, Faculty of Medicine , Monash University , Victoria , Australia.,b Baker IDI Heart and Diabetes Institute , The Alfred Medical Research and Education Precinct , Melbourne , Victoria 3004 , Australia
| | - Scott Maxwell
- a Central Clinical School, Faculty of Medicine , Monash University , Victoria , Australia.,b Baker IDI Heart and Diabetes Institute , The Alfred Medical Research and Education Precinct , Melbourne , Victoria 3004 , Australia
| | - Giuseppe D Ciccotosto
- c Department of Pathology , The University of Melbourne , Parkville , Victoria , Australia.,d Bio21 Molecular science and Biotechnology Institute , Victoria , Australia
| | - Assam El-Osta
- a Central Clinical School, Faculty of Medicine , Monash University , Victoria , Australia.,b Baker IDI Heart and Diabetes Institute , The Alfred Medical Research and Education Precinct , Melbourne , Victoria 3004 , Australia.,c Department of Pathology , The University of Melbourne , Parkville , Victoria , Australia.,e Hong Kong Institute of Diabetes and Obesity, Prince of Wales Hospital , The Chinese University of Hong Kong , Hong Kong SAR
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7
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Truong PH, Ciccotosto GD, Merson TD, Spoerri L, Chuei MJ, Ayers M, Xing YL, Emery B, Cappai R. Amyloid precursor protein and amyloid precursor-like protein 2 have distinct roles in modulating myelination, demyelination, and remyelination of axons. Glia 2018; 67:525-538. [DOI: 10.1002/glia.23561] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 12/14/2022]
Affiliation(s)
- Phan H. Truong
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
- Department of Pharmacology and Therapeutics; The University of Melbourne; Melbourne Victoria Australia
| | - Giuseppe D. Ciccotosto
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
- Department of Pharmacology and Therapeutics; The University of Melbourne; Melbourne Victoria Australia
| | - Tobias D. Merson
- The Florey Institute of Neuroscience and Mental Health; The University of Melbourne; Melbourne Victoria Australia
| | - Loredana Spoerri
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
| | - Mun Joo Chuei
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
| | - Margaret Ayers
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
| | - Yao Lulu Xing
- The Florey Institute of Neuroscience and Mental Health; The University of Melbourne; Melbourne Victoria Australia
| | - Ben Emery
- The Florey Institute of Neuroscience and Mental Health; The University of Melbourne; Melbourne Victoria Australia
- Department of Anatomy and Neuroscience; The University of Melbourne; Melbourne Victoria Australia
| | - Roberto Cappai
- Department of Pathology; The University of Melbourne; Melbourne Victoria Australia
- The Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne Victoria Australia
- Department of Pharmacology and Therapeutics; The University of Melbourne; Melbourne Victoria Australia
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8
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Truong PH, Ciccotosto GD, Cappai R. Analysis of Motor Function in Amyloid Precursor-Like Protein 2 Knockout Mice: The Effects of Ageing and Sex. Neurochem Res 2018; 44:1356-1366. [PMID: 30362021 DOI: 10.1007/s11064-018-2669-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 10/18/2018] [Accepted: 10/20/2018] [Indexed: 12/19/2022]
Abstract
The amyloid precursor protein (APP) is a member of a conserved gene family that includes the amyloid precursor-like proteins 1 (APLP1) and 2 (APLP2). APP and APLP2 share a high degree of similarity, and have overlapping patterns of spatial and temporal expression in the central and peripheral tissues, in particular at the neuromuscular junction. APP-family knockout (KO) studies have helped elucidate aspects of function and functional redundancy amongst the APP-family members. In the present study, we investigated motor performance of APLP2-KO mice and the effect sex differences and age-related changes have on motor performance. APLP2-KO and WT (on C57Bl6 background) littermates control mice from 8 (young adulthood) to 48 weeks (middle age) were investigated. Analysis of motor neuron and muscle morphology showed APLP2-KO females but not males, had less age-related motor function impairments. We observed age and sex differences in both motor neuron number and muscle fiber size distribution for APLP2-KO mice compared to WT (C57Bl6). These alterations in the motor neuron number and muscle fiber distribution pattern may explain why female APLP2-KO mice have far better motor function behaviour during ageing.
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Affiliation(s)
- Phan H Truong
- Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Giuseppe D Ciccotosto
- Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Roberto Cappai
- Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, VIC, 3010, Australia.
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9
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Luu L, Ciccotosto GD, Vella LJ, Cheng L, Roisman LC, Multhaup G, Hill AF, Munter LM, Cappai R. Amyloid Precursor Protein Dimerisation Reduces Neurite Outgrowth. Mol Neurobiol 2018; 56:13-28. [PMID: 29675574 DOI: 10.1007/s12035-018-1070-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 04/09/2018] [Indexed: 02/08/2023]
Abstract
The amyloid precursor protein (APP) undergoes extensive metabolism, and its transport and proteolytic processing can be modulated by its ability to form a homodimer. We have investigated the functional consequences of stabilised APP dimer expression in cells by studying the engineered dimerisation of the APPL17C (residue 17 in Aβ sequence) construct, which is associated with a 30% increase in APP dimer expression, on APP's neurite outgrowth promoting activity. Overexpression of APPL17C in SH-SY5Y cells decreased neurite outgrowth upon retinoic acid differentiation as compared to overexpressing APPWT cells. The APPL17C phenotype was rescued by replacing the APPL17C media with conditioned media from APPWT cells, indicating that the APPL17C mutant is impairing the secretion of a neuritogenic promoting factor. APPL17C had altered transport and was localised in the endoplasmic reticulum. Defining the molecular basis of the APPL17C phenotype showed that RhoA GTPase activity, a negative regulator of neurite outgrowth, was increased in APPL17C cells. RhoA activity was decreased after APPWT conditioned media rescue. Moreover, treatment with the RhoA inhibitor, Y27632, restored a wild-type morphology to the APPL17C cells. Small RNAseq analysis of APPL17C and APPWT cells identified several differentially expressed miRNAs relating to neurite outgrowth. Of these, miR-34a showed the greatest decrease in expression. Lentiviral-mediated overexpression of miR-34a rescued neurite outgrowth in APPL17C cells to APPWT levels and changed RhoA activation. This study has identified a novel link between APP dimerisation and its neuritogenic activity which is mediated by miR-34a expression.
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Affiliation(s)
- Luan Luu
- Department of Pathology, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Giuseppe D Ciccotosto
- Department of Pathology, The University of Melbourne, Melbourne, VIC, 3010, Australia.,Department of Pharmacology & Therapeutics, The University of Melbourne, Melbourne, VIC, 3010, Australia.,Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Laura J Vella
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Lesley Cheng
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Laila C Roisman
- Department of Pathology, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Gerhard Multhaup
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Andrew F Hill
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Lisa-Marie Munter
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Roberto Cappai
- Department of Pathology, The University of Melbourne, Melbourne, VIC, 3010, Australia. .,Department of Pharmacology & Therapeutics, The University of Melbourne, Melbourne, VIC, 3010, Australia.
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10
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Dai C, Ciccotosto GD, Cappai R, Wang Y, Tang S, Hoyer D, Schneider EK, Velkov T, Xiao X. Rapamycin Confers Neuroprotection against Colistin-Induced Oxidative Stress, Mitochondria Dysfunction, and Apoptosis through the Activation of Autophagy and mTOR/Akt/CREB Signaling Pathways. ACS Chem Neurosci 2018; 9:824-837. [PMID: 29257864 DOI: 10.1021/acschemneuro.7b00323] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Our previous studies showed that colistin-induced neurotoxicity involves apoptosis and oxidative damage. The present study demonstrates a neuroprotective effect of rapamycin against colistin-induced neurotoxicity in vitro and in vivo. In a mouse model, colistin treatment (18 mg/kg/d; 14 days) produced marked neuronal mitochondria damage in the cerebral cortex and increased activation of caspase-9 and -3. Rapamycin cotreatment (2.5 mg/kg/d) effectively reduced this neurotoxic effect. In an in vitro mouse neuroblastoma-2a (N2a) cell culture model, rapamycin pretreatment (500 nM) reduced colistin (200 μM) induced cell death from ∼50% to 72%. Moreover, rapamycin showed a marked neuroprotective effect in the N2a cells by decreasing intracellular reactive oxygen species (ROS) production and by up-regulating the activities of the anti-ROS enzymes superoxide dismutase and catalase and recovering glutathione (GSH) levels to normal. Moreover, rapamycin pretreatment protected against colistin-induced mitochondrial dysfunction, caspase activation, and subsequent apoptosis by up-regulating autophagy and activating the Akt/CREB, NGF, and Nrf2 pathways, while inhibiting p53 signaling. Taken together, this is the first study to demonstrate that rapamycin protects against colistin-induced neurotoxicity by activating autophagy, inhibiting oxidative stress, mitochondria dysfunction, and apoptosis. Our data highlight that regulating autophagy to rescue neurons from apoptosis may become a new targeted therapy to relieve the adverse neurotoxic effects associated with colistin therapy.
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Affiliation(s)
- Chongshan Dai
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, No.2 Yuanmingyuan West Road, Beijing 100193, P. R. China
| | - Giuseppe D. Ciccotosto
- Department of Pathology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3052, Australia
| | - Roberto Cappai
- Department of Pathology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3052, Australia
| | - Yang Wang
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, No.2 Yuanmingyuan West Road, Beijing 100193, P. R. China
| | - Shusheng Tang
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, No.2 Yuanmingyuan West Road, Beijing 100193, P. R. China
| | - Daniel Hoyer
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, Victoria 3052, Australia
- Department of Molecular Medicine, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037, United States
| | - Elena K. Schneider
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Tony Velkov
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Xilong Xiao
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, No.2 Yuanmingyuan West Road, Beijing 100193, P. R. China
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Jamasbi E, Hossain MA, Tan M, Separovic F, Ciccotosto GD. Fluorescence imaging of the interaction of amyloid beta 40 peptides with live cells and model membrane. Biochim Biophys Acta Biomembr 2018; 1860:1609-1615. [PMID: 29408451 DOI: 10.1016/j.bbamem.2018.01.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 01/23/2018] [Accepted: 01/27/2018] [Indexed: 11/30/2022]
Abstract
Amyloid beta peptides (Aβ) found in plaques in the brain have been widely recognised as a hallmark of Alzheimer's disease although the underlying mechanism is still unknown. Aβ40 and Aβ40(A2T) peptides were synthesized and their effects on neuronal cells are reported together with the effect of tetramer forms of the peptides. ThT assay revealed that mutation affected the lag time and aggregation and the presence of lipid vesicles changed the fibril formation profile for both peptides. The A2T mutation appeared to reduce cytotoxicity and lessen binding of Aβ40 peptides to neuronal cells. Fluorescence microscopy of the interaction between Aβ40 peptides and giant unilamellar vesicles revealed that both peptides led to formation of smaller vesicles although the tetramer of Aβ(A2T) appeared to promote vesicle aggregation. This article is part of a Special Issue entitled: Protein Aggregation and Misfolding at the Cell Membrane Interface edited by Ayyalusamy Ramamoorthy.
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Affiliation(s)
- Elaheh Jamasbi
- School of Chemistry, Bio21 Institute, The University of Melbourne, VIC 3010, Australia
| | - Mohammed Akhter Hossain
- School of Chemistry, Bio21 Institute, The University of Melbourne, VIC 3010, Australia; The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, VIC 3010, Australia
| | - Marsha Tan
- Department of Pathology, The University of Melbourne, VIC 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, The University of Melbourne, VIC 3010, Australia.
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12
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Dai C, Ciccotosto GD, Cappai R, Wang Y, Tang S, Xiao X, Velkov T. Minocycline attenuates colistin-induced neurotoxicity via suppression of apoptosis, mitochondrial dysfunction and oxidative stress. J Antimicrob Chemother 2017; 72:1635-1645. [PMID: 28204513 DOI: 10.1093/jac/dkx037] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 01/18/2017] [Indexed: 11/13/2022] Open
Abstract
Background Neurotoxicity is an adverse effect patients experience during colistin therapy. The development of effective neuroprotective agents that can be co-administered during polymyxin therapy remains a priority area in antimicrobial chemotherapy. The present study investigates the neuroprotective effect of the synergistic tetracycline antibiotic minocycline against colistin-induced neurotoxicity. Methods The impact of minocycline pretreatment on colistin-induced apoptosis, caspase activation, oxidative stress and mitochondrial dysfunction were investigated using cultured mouse neuroblastoma-2a (N2a) and primary cortical neuronal cells. Results Colistin-induced neurotoxicity in mouse N2a and primary cortical cells gives rise to the generation of reactive oxygen species (ROS) and subsequent cell death via apoptosis. Pretreatment of the neuronal cells with minocycline at 5, 10 and 20 μM for 2 h prior to colistin (200 μM) exposure (24 h), had an neuroprotective effect by significantly decreasing intracellular ROS production and by upregulating the activities of the anti-ROS enzymes superoxide dismutase and catalase. Minocycline pretreatment also protected the cells from colistin-induced mitochondrial dysfunction, caspase activation and subsequent apoptosis. Immunohistochemical imaging studies revealed colistin accumulates within the dendrite projections and cell body of primary cortical neuronal cells. Conclusions To our knowledge, this is first study demonstrating the protective effect of minocycline on colistin-induced neurotoxicity by scavenging of ROS and suppression of apoptosis. Our study highlights that co-administration of minocycline kills two birds with one stone: in addition to its synergistic antimicrobial activity, minocycline could potentially ameliorate unwanted neurotoxicity in patients undergoing polymyxin therapy.
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Affiliation(s)
- Chongshan Dai
- College of Veterinary Medicine, China Agricultural University, 2 Yuanmingyuan West Road, Beijing 100193, People's Republic of China
| | - Giuseppe D Ciccotosto
- Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia
| | - Roberto Cappai
- Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia
| | - Yang Wang
- College of Veterinary Medicine, China Agricultural University, 2 Yuanmingyuan West Road, Beijing 100193, People's Republic of China
| | - Shusheng Tang
- College of Veterinary Medicine, China Agricultural University, 2 Yuanmingyuan West Road, Beijing 100193, People's Republic of China
| | - Xilong Xiao
- College of Veterinary Medicine, China Agricultural University, 2 Yuanmingyuan West Road, Beijing 100193, People's Republic of China
| | - Tony Velkov
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
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Abstract
Central nervous system (CNS) infections caused by multi-drug resistant (MDR) Gram-negative bacteria present a major health and economic burden worldwide. Due to the nearly empty antibiotic discovery pipeline, polymyxins (i.e. polymyxin B and colistin) are used as the last-line therapy against Gram-negative 'superbugs' when all other treatment modalities have failed. The treatment of CNS infections due to multi-drug resistant Gram-negative bacteria is problematic and associated with high mortality rates. Colistin shows significant efficacy for the treatment of CNS infections caused by MDR Gram-negative bacteria that are resistant to all other antibiotics. In particular, MDR Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae which are resistant to expanded-spectrum and fourth-generation cephalosporins, carbapenems and aminoglycosides, represent a major therapeutic challenge, although they can be treated with colistin or polymyxin B. However, current dosing recommendations of intrathecal/intraventricular polymyxins are largely empirical, as we have little understanding of the pharmacokinetics/pharmacodynamics and, importantly, we are only starting to understand the mechanisms of potential neurotoxicity. This review covers the current knowledge-base on the mechanisms of disposition and potential neurotoxicity of polymyxins as well as the combined use of neuroprotective agents to alleviate polymyxins-related neurotoxicity. Progress in this field will provide the urgently needed pharmacological information for safer and more efficacious intrathecal/intraventricular polymyxin therapy against life-threatening CNS infections caused by Gram-negative 'superbugs'.
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Affiliation(s)
- Tony Velkov
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.
| | - Chongshan Dai
- College of Veterinary Medicine, China Agricultural University, Yuanmingyuan West Road, Beijing 100193, PR China
| | - Giuseppe D Ciccotosto
- Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia
| | - Roberto Cappai
- Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia
| | - Daniel Hoyer
- Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, Victoria 3010, Australia; The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, Victoria 3052, Australia; Department of Molecular Medicine, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jian Li
- Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
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14
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Dai C, Ciccotosto GD, Cappai R, Tang S, Li D, Xie S, Xiao X, Velkov T. Curcumin Attenuates Colistin-Induced Neurotoxicity in N2a Cells via Anti-inflammatory Activity, Suppression of Oxidative Stress, and Apoptosis. Mol Neurobiol 2016; 55:421-434. [PMID: 27957686 DOI: 10.1007/s12035-016-0276-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 10/30/2016] [Indexed: 01/06/2023]
Abstract
Neurotoxicity is an unwanted side-effect seen in patients receiving therapy with the "last-line" polymyxin antibiotics. This is the first study to show that colistin-induced neurotoxicity in neuroblastoma-2a (N2a) cells gives rise to an inflammatory response involving the IL-1β/p-IκB-α/NF-κB pathway. Pretreatment with curcumin at 5, 10, and 20 μM for 2 h prior to colistin (200 μM) exposure for 24 h, produced an anti-inflammatory effect by significantly down-regulating the expression of the pro-inflammatory mediators cyclooxygenase-2 (COX-2), phosphorylation of the inhibitor of nuclear factor-kappa B (NF-κB) (p-IκB)-α, and concomitantly NF-κB levels. Moreover, curcumin significantly decreased intracellular reactive oxygen species (ROS) production and increased the activities of the anti-ROS enzymes superoxide dismutase, catalase, and the intracellular levels of glutathione. Curcumin pretreatment also protected the cells from colistin-induced mitochondrial dysfunction, caspase activation, and subsequent apoptosis. Overall, our findings demonstrate for the first time, a potential role for curcumin for treating polymyxin-induced neurotoxicity through the modulation of NF-κB signaling and its potent anti-oxidative and anti-apoptotic effects.
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Affiliation(s)
- Chongshan Dai
- College of Veterinary Medicine, China Agricultural University, 2 Yuanmingyuan West Road, Beijing, 100193, People's Republic of China
| | - Giuseppe D Ciccotosto
- Department of Pathology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Roberto Cappai
- Department of Pathology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Shusheng Tang
- College of Veterinary Medicine, China Agricultural University, 2 Yuanmingyuan West Road, Beijing, 100193, People's Republic of China
| | - Daowen Li
- College of Veterinary Medicine, China Agricultural University, 2 Yuanmingyuan West Road, Beijing, 100193, People's Republic of China
| | - Sanlei Xie
- College of Veterinary Medicine, China Agricultural University, 2 Yuanmingyuan West Road, Beijing, 100193, People's Republic of China
| | - Xilong Xiao
- College of Veterinary Medicine, China Agricultural University, 2 Yuanmingyuan West Road, Beijing, 100193, People's Republic of China.
| | - Tony Velkov
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia.
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15
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Jana MK, Cappai R, Ciccotosto GD. Oligomeric Amyloid-β Toxicity Can Be Inhibited by Blocking Its Cellular Binding in Cortical Neuronal Cultures with Addition of the Triphenylmethane Dye Brilliant Blue G. ACS Chem Neurosci 2016; 7:1141-7. [PMID: 27258855 DOI: 10.1021/acschemneuro.6b00108] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Accumulation of soluble amyloid β (Aβ) oligomers in the brain has been suggested to cause neurodegeneration associated with Alzheimer's disease (AD). Our previous findings showed that the binding of Aβ trimer and tetramer to neurons is significantly correlated with Aβ-induced neuronal cell death. We propose blocking of neuronal binding of these neurotoxic Aβ oligomers as a therapeutic strategy for preventing this disease. To test this, a nontoxic triphenylmethane dye, Brilliant Blue G (BBG), which has been reported to modulate Aβ aggregation and neurotoxicity, was investigated using mouse primary cortical neuronal cultures treated with photoinduced cross-linked toxic Aβ40 oligomers as well as soluble Aβ40 and Aβ42 peptides. We found that the BBG-induced decrease in Aβ binding resulted in a significant decrease in its neurotoxicity. These findings support our hypothesis that disruption of cellular Aβ binding is a promising therapeutic strategy for combating AD.
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Affiliation(s)
- Metta K. Jana
- Department of Pathology, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Roberto Cappai
- Department of Pathology, The University of Melbourne, Parkville, VIC 3010, Australia
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16
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Dinet V, Ciccotosto GD, Delaunay K, Borras C, Ranchon-Cole I, Kostic C, Savoldelli M, El Sanharawi M, Jonet L, Pirou C, An N, Abitbol M, Arsenijevic Y, Behar-Cohen F, Cappai R, Mascarelli F. Amyloid Precursor-Like Protein 2 deletion-induced retinal synaptopathy related to congenital stationary night blindness: structural, functional and molecular characteristics. Mol Brain 2016; 9:64. [PMID: 27267879 PMCID: PMC4897877 DOI: 10.1186/s13041-016-0245-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 05/30/2016] [Indexed: 12/03/2022] Open
Abstract
Background Amyloid precursor protein knockout mice (APP-KO) have impaired differentiation of amacrine and horizontal cells. APP is part of a gene family and its paralogue amyloid precursor-like protein 2 (APLP2) has both shared as well as distinct expression patterns to APP, including in the retina. Given the impact of APP in the retina we investigated how APLP2 expression affected the retina using APLP2 knockout mice (APLP2-KO). Results Using histology, morphometric analysis with noninvasive imaging technique and electron microscopy, we showed that APLP2-KO retina displayed abnormal formation of the outer synaptic layer, accompanied with greatly impaired photoreceptor ribbon synapses in adults. Moreover, APLP2-KO displayed a significant decease in ON-bipolar, rod bipolar and type 2 OFF-cone bipolar cells (36, 21 and 63 %, respectively). Reduction of the number of bipolar cells was accompanied with disrupted dendrites, reduced expression of metabotropic glutamate receptor 6 at the dendritic tips and alteration of axon terminals in the OFF laminae of the inner plexiform layer. In contrast, the APP-KO photoreceptor ribbon synapses and bipolar cells were intact. The APLP2-KO retina displayed numerous phenotypic similarities with the congenital stationary night blindness, a non-progressive retinal degeneration disease characterized by the loss of night vision. The pathological phenotypes in the APLP2-KO mouse correlated to altered transcription of genes involved in pre- and postsynatic structure/function, including CACNA1F, GRM6, TRMP1 and Gα0, and a normal scotopic a-wave electroretinogram amplitude, markedly reduced scotopic electroretinogram b-wave and modestly reduced photopic cone response. This confirmed the impaired function of the photoreceptor ribbon synapses and retinal bipolar cells, as is also observed in congenital stationary night blindness. Since congenital stationary night blindness present at birth, we extended our analysis to retinal differentiation and showed impaired differentiation of different bipolar cell subtypes and an altered temporal sequence of development from OFF to ON laminae in the inner plexiform layer. This was associated with the altered expression patterns of bipolar cell generation and differentiation factors, including MATH3, CHX10, VSX1 and OTX2. Conclusions These findings demonstrate that APLP2 couples retina development and synaptic genes and present the first evidence that APLP2 expression may be linked to synaptic disease. Electronic supplementary material The online version of this article (doi:10.1186/s13041-016-0245-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Virginie Dinet
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Giuseppe D Ciccotosto
- Department of Pathology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia
| | - Kimberley Delaunay
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Céline Borras
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Isabelle Ranchon-Cole
- Laboratoire de Biophysique Sensorielle, Université Clermont 1, Clermont-Ferrand, France
| | - Corinne Kostic
- Unit of Gene Therapy & Stem Cell Biology, University of Lausanne, Jules-Gonin Eye Hospital, Lausanne, Switzerland
| | - Michèle Savoldelli
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Mohamed El Sanharawi
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Laurent Jonet
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Caroline Pirou
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Na An
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Marc Abitbol
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Yvan Arsenijevic
- Unit of Gene Therapy & Stem Cell Biology, University of Lausanne, Jules-Gonin Eye Hospital, Lausanne, Switzerland
| | - Francine Behar-Cohen
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France
| | - Roberto Cappai
- Department of Pathology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia
| | - Frédéric Mascarelli
- Centre de Recherche des Cordeliers, Université Paris Descartes, Université Pierre et Marie Curie, Paris, France.
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Jana MK, Cappai R, Pham CLL, Ciccotosto GD. Membrane-bound tetramer and trimer Aβ oligomeric species correlate with toxicity towards cultured neurons. J Neurochem 2016; 136:594-608. [DOI: 10.1111/jnc.13443] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 11/11/2015] [Accepted: 11/23/2015] [Indexed: 12/12/2022]
Affiliation(s)
- Metta K. Jana
- Department of Pathology; Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Parkville Vic. Australia
| | - Roberto Cappai
- Department of Pathology; Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Parkville Vic. Australia
| | - Chi L. L. Pham
- Department of Pathology; Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Parkville Vic. Australia
| | - Giuseppe D. Ciccotosto
- Department of Pathology; Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Parkville Vic. Australia
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18
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Jamasbi E, Ciccotosto GD, Tailhades J, Robins-Browne RM, Ugalde CL, Sharples RA, Patil N, Wade JD, Hossain MA, Separovic F. Site of fluorescent label modifies interaction of melittin with live cells and model membranes. Biochim Biophys Acta 2015; 1848:2031-9. [PMID: 26051124 DOI: 10.1016/j.bbamem.2015.06.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Revised: 05/30/2015] [Accepted: 06/02/2015] [Indexed: 02/01/2023]
Abstract
The mechanism of membrane disruption by melittin (MLT) of giant unilamellar vesicles (GUVs) and live cells was studied using fluorescence microscopy and two fluorescent synthetic analogues of MLT. The N-terminus of one of these was acylated with thiopropionic acid to enable labeling with maleimido-AlexaFluor 430 to study the interaction of MLT with live cells. It was compared with a second analogue labeled at P14C. The results indicated that the fluorescent peptides adhered to the membrane bilayer of phosphatidylcholine GUVs and inserted into the plasma membrane of HeLa cells. Fluorescence and light microscopy revealed changes in cell morphology after exposure to MLT peptides and showed bleb formation in the plasma membrane of HeLa cells. However, the membrane disruptive effect was dependent upon the location of the fluorescent label on the peptide and was greater when MLT was labeled at the N-terminus. Proline at position 14 appeared to be important for antimicrobial activity, hemolysis and cytotoxicity, but not essential for cell membrane disruption.
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Affiliation(s)
- Elaheh Jamasbi
- School of Chemistry, Bio21 Institute, The University of Melbourne, VIC 3010, Australia
| | | | - Julien Tailhades
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, VIC 3010, Australia
| | - Roy M Robins-Browne
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, VIC 3010, Australia; Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, VIC 3052, Australia
| | - Cathryn L Ugalde
- Department of Biochemistry & Molecular Biology, Bio21 Institute, The University of Melbourne, VIC 3010, Australia
| | - Robyn A Sharples
- Department of Biochemistry & Molecular Biology, Bio21 Institute, The University of Melbourne, VIC 3010, Australia
| | - Nitin Patil
- School of Chemistry, Bio21 Institute, The University of Melbourne, VIC 3010, Australia; The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, VIC 3010, Australia
| | - John D Wade
- School of Chemistry, Bio21 Institute, The University of Melbourne, VIC 3010, Australia; The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, VIC 3010, Australia
| | - Mohammed Akhter Hossain
- School of Chemistry, Bio21 Institute, The University of Melbourne, VIC 3010, Australia; The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, VIC 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, The University of Melbourne, VIC 3010, Australia
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Ciccotosto GD, James SA, Altissimo M, Paterson D, Vogt S, Lai B, de Jonge MD, Howard DL, Bush AI, Cappai R. Quantitation and localization of intracellular redox active metals by X-ray fluorescence microscopy in cortical neurons derived from APP and APLP2 knockout tissue. Metallomics 2014; 6:1894-904. [PMID: 25098278 DOI: 10.1039/c4mt00176a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The amyloid precursor protein (APP) gene family includes APP and the amyloid precursor-like proteins, APLP1 and APLP2. These proteins contain metal binding sites for copper, zinc and iron and are known to have physiological roles in modulating the metal homeostasis in brain cells. Here we report the application of X-ray fluorescence microscopy (XFM) to investigate the subcellular distribution patterns of the metal ions Cu, Zn, Fe, and Ca in individual neurons derived from APP and APLP2 knockout mice brains to further define their role in metal homeostasis. These studies add to the growing body of data that the APP family of proteins are metalloproteins that have shared as well as distinct effects on metals. As we continue to delineate the cellular effects of the APP family of proteins it is important to consider how metals are involved in their actions.
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Affiliation(s)
- Giuseppe D Ciccotosto
- Department of Pathology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia.
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20
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Needham BE, Ciccotosto GD, Cappai R. Combined deletions of amyloid precursor protein and amyloid precursor-like protein 2 reveal different effects on mouse brain metal homeostasis. Metallomics 2014; 6:598-603. [PMID: 24448592 DOI: 10.1039/c3mt00358b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Alterations to the expression of the Amyloid Precursor Protein (APP) and its paralogue Amyloid Precursor-Like Protein 2 (APLP2) affect metal homeostasis in vitro and in vivo. Analysis of the in vivo effects of the APP and APLP2 knockouts on metal homeostasis has been restricted to APP and APLP2 single knockout mice, and up to12 month old animals. To define the redundancy and inter-relationship between the APP and APLP2 genes as regulators of metal homeostasis, and how this is influenced by aging, we investigated copper, iron, zinc and manganese levels in APP and APLP2 single knockout mice as well as homozygous:hemizygous knockout mice at 3, 12 and 18 plus months of age. These studies identified age and genotype dependent changes in metal levels, and established differences in the relative roles played by APP and APLP2 in modulating metal homeostasis.
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Affiliation(s)
- B Elise Needham
- Department of Pathology, The University of Melbourne, VIC 3010, Australia.
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21
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Ciccotosto GD, Kozer N, Chow TTY, Chon JWM, Clayton AHA. Aggregation distributions on cells determined by photobleaching image correlation spectroscopy. Biophys J 2013; 104:1056-64. [PMID: 23473488 DOI: 10.1016/j.bpj.2013.01.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 12/17/2012] [Accepted: 01/02/2013] [Indexed: 11/29/2022] Open
Abstract
The organization of molecules into macromolecular (nanometer scale), supramolecular complexes (submicron-to-micron scale), and within subcellular domains, is an important architectural principle of cellular biology and biochemistry. Determining the precise nature and distribution of complexes within the cellular milieu is a challenging biophysical problem. Time-series analysis of laser scanning confocal microscopy images by image correlation spectroscopy (ICS) or fluctuation moments methods provides information on aggregation, flow, and dynamics of fluorescently tagged macromolecules. All the methods to date require a brightness standard to relate the experimental data to absolute aggregation. In this article, we show that ICS as a function of gradual photobleaching is a sensitive indicator of aggregation distribution on the submicron scale. Specifically, in photobleaching ICS, the extent of nonlinearity of the apparent cluster density as a function of bleaching is related to the size of clusters. The analysis is tested using computer simulations on model aggregate systems and then applied to an experimental determination of Aβ peptide aggregation on nerve cells. The analysis reveals time-dependent increases in Aβ1-42 peptide aggregation. Globally, the datasets could be described by a monomer-dimer-tetramer-hexamer or a monomer-dimer-trimer-pentamer model. The results demonstrate the utility of photobleaching with ICS for determining aggregation states on the supramolecular scale in intact cells without the requirement for a brightness standard.
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Affiliation(s)
- Giuseppe D Ciccotosto
- Department of Pathology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Australia
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Tan JL, Li QX, Ciccotosto GD, Crouch PJ, Culvenor JG, White AR, Evin G. Mild oxidative stress induces redistribution of BACE1 in non-apoptotic conditions and promotes the amyloidogenic processing of Alzheimer's disease amyloid precursor protein. PLoS One 2013; 8:e61246. [PMID: 23613819 PMCID: PMC3629182 DOI: 10.1371/journal.pone.0061246] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Accepted: 03/07/2013] [Indexed: 12/22/2022] Open
Abstract
BACE1 is responsible for β-secretase cleavage of the amyloid precursor protein (APP), which represents the first step in the production of amyloid β (Aβ) peptides. Previous reports, by us and others, have indicated that the levels of BACE1 protein and activity are increased in the brain cortex of patients with Alzheimer's disease (AD). The association between oxidative stress (OS) and AD has prompted investigations that support the potentiation of BACE1 expression and enzymatic activity by OS. Here, we have established conditions to analyse the effects of mild, non-lethal OS on BACE1 in primary neuronal cultures, independently from apoptotic mechanisms that were shown to impair BACE1 turnover. Six-hour treatment of mouse primary cortical cells with 10-40 µM hydrogen peroxide did not significantly compromise cell viability but it did produce mild oxidative stress (mOS), as shown by the increased levels of reactive radical species and activation of p38 stress kinase. The endogenous levels of BACE1 mRNA and protein were not significantly altered in these conditions, whereas a toxic H2O2 concentration (100 µM) caused an increase in BACE1 protein levels. Notably, mOS conditions resulted in increased levels of the BACE1 C-terminal cleavage product of APP, β-CTF. Subcellular fractionation techniques showed that mOS caused a major rearrangement of BACE1 localization from light to denser fractions, resulting in an increased distribution of BACE1 in fractions containing APP and markers for trans-Golgi network and early endosomes. Collectively, these data demonstrate that mOS does not modify BACE1 expression but alters BACE1 subcellular compartmentalization to favour the amyloidogenic processing of APP, and thus offer new insight in the early molecular events of AD pathogenesis.
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Affiliation(s)
- Jiang-Li Tan
- Department of Pathology, The University of Melbourne, Parkville, Australia
| | - Qiao-Xin Li
- Neuropathology Laboratory, Mental Health Division, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - Giuseppe D. Ciccotosto
- Department of Pathology, The University of Melbourne, Parkville, Australia
- Neuropathology Laboratory, Mental Health Division, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
- BIO21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - Peter John Crouch
- Department of Pathology, The University of Melbourne, Parkville, Australia
- Neuropathology Laboratory, Mental Health Division, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - Janetta Gladys Culvenor
- Department of Pathology, The University of Melbourne, Parkville, Australia
- Neuropathology Laboratory, Mental Health Division, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - Anthony Robert White
- Department of Pathology, The University of Melbourne, Parkville, Australia
- Neuropathology Laboratory, Mental Health Division, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - Genevieve Evin
- Department of Pathology, The University of Melbourne, Parkville, Australia
- Neuropathology Laboratory, Mental Health Division, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
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Kok WM, Cottam JM, Ciccotosto GD, Miles LA, Karas JA, Scanlon DB, Roberts BR, Parker MW, Cappai R, Barnham KJ, Hutton CA. Synthetic dityrosine-linked β-amyloid dimers form stable, soluble, neurotoxic oligomers. Chem Sci 2013. [DOI: 10.1039/c3sc22295k] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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24
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Cheng F, Cappai R, Ciccotosto GD, Svensson G, Multhaup G, Fransson LÅ, Mani K. Suppression of amyloid beta A11 antibody immunoreactivity by vitamin C: possible role of heparan sulfate oligosaccharides derived from glypican-1 by ascorbate-induced, nitric oxide (NO)-catalyzed degradation. J Biol Chem 2011; 286:27559-72. [PMID: 21642435 DOI: 10.1074/jbc.m111.243345] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Amyloid β (Aβ) is generated from the copper- and heparan sulfate (HS)-binding amyloid precursor protein (APP) by proteolytic processing. APP supports S-nitrosylation of the HS proteoglycan glypican-1 (Gpc-1). In the presence of ascorbate, there is NO-catalyzed release of anhydromannose (anMan)-containing oligosaccharides from Gpc-1-nitrosothiol. We investigated whether these oligosaccharides interact with Aβ during APP processing and plaque formation. anMan immunoreactivity was detected in amyloid plaques of Alzheimer (AD) and APP transgenic (Tg2576) mouse brains by immunofluorescence microscopy. APP/APP degradation products detected by antibodies to the C terminus of APP, but not Aβ oligomers detected by the anti-Aβ A11 antibody, colocalized with anMan immunoreactivity in Tg2576 fibroblasts. A 50-55-kDa anionic, sodium dodecyl sulfate-stable, anMan- and Aβ-immunoreactive species was obtained from Tg2576 fibroblasts using immunoprecipitation with anti-APP (C terminus). anMan-containing HS oligo- and disaccharide preparations modulated or suppressed A11 immunoreactivity and oligomerization of Aβ42 peptide in an in vitro assay. A11 immunoreactivity increased in Tg2576 fibroblasts when Gpc-1 autoprocessing was inhibited by 3-β[2(diethylamino)ethoxy]androst-5-en-17-one (U18666A) and decreased when Gpc-1 autoprocessing was stimulated by ascorbate. Neither overexpression of Gpc-1 in Tg2576 fibroblasts nor addition of copper ion and NO donor to hippocampal slices from 3xTg-AD mice affected A11 immunoreactivity levels. However, A11 immunoreactivity was greatly suppressed by the subsequent addition of ascorbate. We speculate that temporary interaction between the Aβ domain and small, anMan-containing oligosaccharides may preclude formation of toxic Aβ oligomers. A portion of the oligosaccharides are co-secreted with the Aβ peptides and deposited in plaques. These results support the notion that an inadequate supply of vitamin C could contribute to late onset AD in humans.
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Affiliation(s)
- Fang Cheng
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, Biomedical Center A13, SE-221 84 Lund, Sweden
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25
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Dinet V, An N, Ciccotosto GD, Bruban J, Maoui A, Bellingham SA, Hill AF, Andersen OM, Nykjaer A, Jonet L, Cappai R, Mascarelli F. APP involvement in retinogenesis of mice. Acta Neuropathol 2011; 121:351-63. [PMID: 20978902 DOI: 10.1007/s00401-010-0762-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 10/11/2010] [Accepted: 10/14/2010] [Indexed: 12/23/2022]
Abstract
Very few studies have examined expression and function of amyloid precursor protein (APP) in the retina. We showed that APP mRNA and protein are expressed according to the different waves of retinal differentiation. Depletion of App led to an absence of amacrine cells, a 50% increase in the number of horizontal cells and alteration of the synapses. The retinas of adult APP(-/-) mice showed only half as many glycinergic amacrine cells as wild-type retinas. We identified Ptf1a, which plays a role in controlling both amacrine and horizontal cell fates, as a downstream effector of APP. The observation of a similar phenotype in sorLA knockout mice, a major regulator of APP processing, suggests that regulation of APP functions via sorLA controls the determination of amacrine and horizontal cell fate. These findings provide novel insights that indicate that APP plays an important role in retinal differentiation.
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Affiliation(s)
- Virginie Dinet
- Centre de Recherche des Cordeliers, Université Pierre et Marie Curie, Paris 6, INSERM, 15 rue de l'Ecole de Médecine, Paris, France
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26
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Perreau VM, Orchard S, Adlard PA, Bellingham SA, Cappai R, Ciccotosto GD, Cowie TF, Crouch PJ, Duce JA, Evin G, Faux NG, Hill AF, Hung YH, James SA, Li QX, Mok SS, Tew DJ, White AR, Bush AI, Hermjakob H, Masters CL. A domain level interaction network of amyloid precursor protein and Aβ of Alzheimer's disease. Proteomics Clin Appl 2010. [DOI: 10.1002/prca.201090068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Perreau VM, Orchard S, Adlard PA, Bellingham SA, Cappai R, Ciccotosto GD, Cowie TF, Crouch PJ, Duce JA, Evin G, Faux NG, Hill AF, Hung YH, James SA, Li QX, Mok SS, Tew DJ, White AR, Bush AI, Hermjakob H, Masters CL. A domain level interaction network of amyloid precursor protein and Abeta of Alzheimer's disease. Proteomics 2010; 10:2377-95. [PMID: 20391539 DOI: 10.1002/pmic.200900773] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The primary constituent of the amyloid plaque, beta-amyloid (Abeta), is thought to be the causal "toxic moiety" of Alzheimer's disease. However, despite much work focused on both Abeta and its parent protein, amyloid precursor protein (APP), the functional roles of APP and its cleavage products remain to be fully elucidated. Protein-protein interaction networks can provide insight into protein function, however, high-throughput data often report false positives and are in frequent disagreement with low-throughput experiments. Moreover, the complexity of the CNS is likely to be under represented in such databases. Therefore, we curated the published work characterizing both APP and Abeta to create a protein interaction network of APP and its proteolytic cleavage products, with annotation, where possible, to the level of APP binding domain and isoform. This is the first time that an interactome has been refined to domain level, essential for the interpretation of APP due to the presence of multiple isoforms and processed fragments. Gene ontology and network analysis were used to identify potentially novel functional relationships among interacting proteins.
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Affiliation(s)
- Victoria M Perreau
- Neuroproteomics and Neurogenomics Platform, National Neurosciences Facility, The University of Melbourne, Parkville, VIC, Australia.
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28
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Smith DG, Ciccotosto GD, Tew DJ, Perez K, Curtain CC, Boas JF, Masters CL, Cappai R, Barnham KJ. Histidine 14 Modulates Membrane Binding and Neurotoxicity of the Alzheimer's Disease Amyloid-β Peptide. ACTA ACUST UNITED AC 2010; 19:1387-400. [DOI: 10.3233/jad-2010-1334] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Danielle G. Smith
- Department of Pathology, The University of Melbourne Parkville, Victoria, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne Parkville, Victoria, Australia
| | - Giuseppe D. Ciccotosto
- Department of Pathology, The University of Melbourne Parkville, Victoria, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne Parkville, Victoria, Australia
- Mental Health Research Institute, The University of Melbourne Parkville, Victoria, Australia
| | - Deborah J. Tew
- Department of Pathology, The University of Melbourne Parkville, Victoria, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne Parkville, Victoria, Australia
- Mental Health Research Institute, The University of Melbourne Parkville, Victoria, Australia
| | - Keyla Perez
- Department of Pathology, The University of Melbourne Parkville, Victoria, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne Parkville, Victoria, Australia
- Mental Health Research Institute, The University of Melbourne Parkville, Victoria, Australia
| | - Cyril C. Curtain
- Department of Pathology, The University of Melbourne Parkville, Victoria, Australia
| | - John F. Boas
- School of Physics, Monash University, Monash, Australia
| | - Colin L. Masters
- Mental Health Research Institute, The University of Melbourne Parkville, Victoria, Australia
- Centre for Neuroscience, The University of Melbourne Parkville, Victoria, Australia
| | - Roberto Cappai
- Department of Pathology, The University of Melbourne Parkville, Victoria, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne Parkville, Victoria, Australia
| | - Kevin J. Barnham
- Department of Pathology, The University of Melbourne Parkville, Victoria, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne Parkville, Victoria, Australia
- Mental Health Research Institute, The University of Melbourne Parkville, Victoria, Australia
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29
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Abramov E, Dolev I, Fogel H, Ciccotosto GD, Ruff E, Slutsky I. Amyloid-β as a positive endogenous regulator of release probability at hippocampal synapses. Nat Neurosci 2009; 12:1567-76. [DOI: 10.1038/nn.2433] [Citation(s) in RCA: 371] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Accepted: 09/25/2009] [Indexed: 01/18/2023]
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30
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Ciccotosto GD, Tew D, Drew SC, Smith DG, Johanssen T, Lal V, Lau T, Perez K, Curtain C, Wade JD, Separovic F, Masters CL, Smith JP, Barnham KJ, Cappai R. P4‐213: Stereospecific interactions are necessary for Alzheimer's disease amyloid‐beta toxicity. Alzheimers Dement 2009. [DOI: 10.1016/j.jalz.2009.04.679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Giuseppe D. Ciccotosto
- The University of MelbourneParkvilleVictoriaAustralia
- Mental Health Research InstituteParkvilleVictoriaAustralia
| | - Deborah Tew
- The University of MelbourneParkvilleVictoriaAustralia
- Mental Health Research InstituteParkvilleVictoriaAustralia
| | - Simon C. Drew
- The University of MelbourneParkvilleVictoriaAustralia
- Mental Health Research InstituteParkvilleVictoriaAustralia
| | | | - Timothy Johanssen
- The University of MelbourneParkvilleVictoriaAustralia
- Mental Health Research InstituteParkvilleVictoriaAustralia
| | - Varsha Lal
- Mental Health Research InstituteParkvilleVictoriaAustralia
| | - Tong‐Lay Lau
- The University of MelbourneParkvilleVictoriaAustralia
| | - Keyla Perez
- The University of MelbourneParkvilleVictoriaAustralia
- Mental Health Research InstituteParkvilleVictoriaAustralia
| | | | - John D. Wade
- The University of MelbourneParkvilleVictoriaAustralia
| | | | | | - Jeffrey P. Smith
- The University of MelbourneParkvilleVictoriaAustralia
- Colorado State UniversityPuebloCOUSA
| | - Kevin J. Barnham
- The University of MelbourneParkvilleVictoriaAustralia
- Mental Health Research InstituteParkvilleVictoriaAustralia
| | - Roberto Cappai
- The University of MelbourneParkvilleVictoriaAustralia
- Mental Health Research InstituteParkvilleVictoriaAustralia
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31
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Needham BE, Wlodek ME, Ciccotosto GD, Fam BC, Masters CL, Proietto J, Andrikopoulos S, Cappai R. Identification of the Alzheimer's disease amyloid precursor protein (APP) and its homologue APLP2 as essential modulators of glucose and insulin homeostasis and growth. J Pathol 2008; 215:155-63. [PMID: 18393365 DOI: 10.1002/path.2343] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The amyloid precursor protein (APP), the source of the neurotoxic amyloid beta (A beta) peptide involved in Alzheimer's disease (AD), belongs to a conserved family of related proteins. In mammals, the APP family contains amyloid precursor-like protein 1 (APLP1) and amyloid precursor-like protein 2 (APLP2). Whilst a number of activities have been attributed to the APP family, an overall function has not been definitively established. While ablating either the APP or APLP2 gene in mice produces minimal phenotypic change, the combined knockout of these genes in mice causes postnatal mortality. Postnatal survival therefore requires a shared but unknown function of APP and APLP2. To investigate the biochemical basis for the postnatal lethality, plasma was analysed from double knockout mice (APP-/- APLP2-/-) 2 days before birth, at gestational day E17, and from mice at 12-16 h after birth. The postnatal double knockouts had 66% lower plasma glucose levels than their wild-type controls and 50% lower than their single knockout counterparts. Interestingly, the postnatal double knockouts displayed hyperinsulinaemia, as shown by inappropriate plasma insulin levels, given their degree of hypoglycaemia. The single knockout mice also showed hyperinsulinaemia and had 31% lower plasma glucose than the wild-types. While the double knockouts did not survive more than 24 h after birth, the single knockouts reached adulthood and their hypoglycaemia continued. Therefore, APP and APLP2 expression modulates plasma insulin and glucose concentrations. Plasma calcium, magnesium and phosphate were also significantly reduced in the double knockouts compared to the wild-types, and they showed distinctive growth restriction, suggesting the involvement of a metabolic impairment. These results link the expression of the APP and APLP2 genes with glucose homeostasis and growth and therefore identify a novel function for the APP family.
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Affiliation(s)
- B E Needham
- Department of Pathology, The University of Melbourne, Victoria 3010, Australia
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32
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Barnham KJ, Kenche VB, Ciccotosto GD, Smith DP, Tew DJ, Liu X, Perez K, Cranston G, Johanssen T, Volitakis I, Bush AI, Masters CL, White AR, Smith JP, Cherny RA, Cappai R. P2‐293: Platinum‐based inhibitors of amyloid‐β as therapeutic agents for Alzheimer's disease. Alzheimers Dement 2008. [DOI: 10.1016/j.jalz.2008.05.1369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | | | | | | | | | - Xiang Liu
- The University of MelbourneParkvilleAustralia
| | - Keyla Perez
- The University of MelbourneParkvilleAustralia
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Abstract
Prion peptide (PrP) neurotoxicity has been modelled in vitro by using synthetic peptides derived from the PrP(C) sequence. The major region of neurotoxicity has been localized to the hydrophobic domain located in the middle of the PrP sequence. The neurotoxicity assays are typically performed on cultured mouse cerebellar neurons derived from neonatal pups, and viability can be monitored by a variety of assays, including MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium); MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt) lactate dehydrogenase release; and apoptotic assays. These neurotoxicity studies have been useful in identifying cofactors, such as PrP(C) and metals as modulators of PrP peptide-mediated neurotoxicity. Given the biosafety issues associated with handling and purifying infectious prions, the use of synthetic peptides that display a dependence upon PrP(C) expression for toxicity, as per the PrP(Sc) agent for infectivity, supports the relevance of using these synthetic peptides for understanding PrP-mediated neurotoxicity.
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Affiliation(s)
- Giuseppe D Ciccotosto
- Department of Pathology and Mental Health Research Institute of Victoria, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Australia
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Du T, Ciccotosto GD, Cranston GA, Kocak G, Masters CL, Crouch PJ, Cappai R, White AR. Neurotoxicity from glutathione depletion is mediated by Cu-dependent p53 activation. Free Radic Biol Med 2008; 44:44-55. [PMID: 18045546 DOI: 10.1016/j.freeradbiomed.2007.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2007] [Revised: 09/05/2007] [Accepted: 09/05/2007] [Indexed: 01/21/2023]
Abstract
Loss of intracellular neuronal glutathione (GSH) is an important feature of neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. The consequences of GSH depletion include increased oxidative damage to proteins, lipids, and DNA and subsequent cytotoxic effects. GSH is also an important modulator of cellular copper (Cu) homeostasis and altered Cu metabolism is central to the pathology of several neurodegenerative diseases. The cytotoxic effects of Cu in cells depleted of GSH are not well understood. We have previously reported that depletion of neuronal GSH levels results in cell death from trace levels of extracellular Cu due to elevated Cu(I)-mediated free radical production. In this study we further examined the molecular pathway of trace Cu toxicity in neurons and fibroblasts depleted of GSH. Treatment of primary cortical neurons or 3T3 fibroblasts with the glutathione synthetase inhibitor buthionine sulfoximine resulted in substantial loss of intracellular GSH and increased cytotoxicity. We found that both neurons and fibroblasts revealed increased expression and activation of p53 after depletion of GSH. The increased p53 activity was induced by extracellular trace Cu. Furthermore, we showed that in GSH-depleted cells, Cu induced an increase in oxidative stress resulting in DNA damage and activation of p53-dependent cell death. These findings may have important implications for neurodegenerative disorders that involve GSH depletion and aberrant Cu metabolism.
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Affiliation(s)
- Tai Du
- Department of Pathology, The University of Melbourne, Melbourne, VIC 3010, Australia
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35
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Abstract
We explored the effect of copper availability on the synthesis and trafficking of peptidylglycine alpha-amidating monooxygenase (PAM), an essential cuproenzyme whose catalytic domains function in the lumen of peptide-containing secretory granules. Corticotrope tumor cell lines expressing integral membrane and soluble forms of PAM were depleted of copper using bathocuproinedisulfonic acid or loaded with copper by incubation with CuCl(2). Depleting cellular copper stimulates basal secretion of soluble enzyme produced by endoproteolytic cleavage of PAM in secretory granules and transit of membrane PAM though the endocytic pathway and back into secretory granules. Unlike many cuproenzymes, lack of copper does not lead to instability of PAM. Copper loading decreases cleavage of PAM in secretory granules, secretion of soluble enzyme, and the return of internalized PAM to secretory granules. The trafficking and stability of the soluble, luminal domain of PAM and truncated membrane PAM lacking a cytosolic domain are not affected by copper availability. Taken together, our data demonstrate a role for copper-sensitive cytosolic machinery in directing endocytosed membrane PAM back to secretory granules or to a degradative pathway. The response of PAM to lack of copper suggests that it facilitates copper homeostasis.
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Affiliation(s)
- Mithu De
- University of Connecticut Health Center, Farmington, Connecticut 06030-3401, USA
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36
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Smith DP, Ciccotosto GD, Tew DJ, Fodero-Tavoletti MT, Johanssen T, Masters CL, Barnham KJ, Cappai R. Concentration Dependent Cu2+Induced Aggregation and Dityrosine Formation of the Alzheimer's Disease Amyloid-β Peptide†. Biochemistry 2007; 46:2881-91. [PMID: 17297919 DOI: 10.1021/bi0620961] [Citation(s) in RCA: 161] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Amyloid beta peptide (Abeta) of Alzheimer's diseases (AD) is closely linked to the progressive cognitive decline associated with the disease. Cu2+ ions can induce the de novo aggregation of the Abeta peptide into non-amyloidogenic aggregates and the production of a toxic species. The mechanism by which Cu2+ mediates the change from amyloid material toward Cu2+ induced aggregates is poorly defined. Here we demonstrate that the aggregation state of Abeta1-42 at neutral pH is governed by the Cu2+:peptide molar ratio. By probing amyloid content and total aggregation, we observed a distinct Cu2+ switching effect centered at equimolar Cu2+:peptide ratios. At sub-equimolar Cu2+:peptide molar ratios, Abeta1-42 forms thioflavin-T reactive amyloid; conversely, at supra-equimolar Cu2+:peptide molar ratios, Abeta1-42 forms both small spherical oligomers approximately 10-20 nm in size and large amorphous aggregates. We demonstrate that these insoluble aggregates form spontaneously via a soluble species without the presence of an observable lag phase. In seeding experiments, the Cu2+ induced aggregates were unable to influence fibril formation or convert into fibrillar material. Aged Cu2+ induced aggregates are toxic when compared to Abeta1-42 aged in the absence of Cu2+. Importantly, the formation of dityrosine crosslinked Abeta, by the oxidative modification of the peptide, only occurs at equimolar molar ratios and above. The formation of dityrosine adducts occurs following the initiation of aggregation and hence does not drive the formation of the Cu2+ induced aggregates. These results define the role Cu2+ plays in modulating the aggregation state and toxicity of Abeta1-42.
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Affiliation(s)
- David P Smith
- Department of Pathology, The University of Melbourne, Victoria, 3010, Australia
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37
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Smith DP, Smith DG, Curtain CC, Boas JF, Pilbrow JR, Ciccotosto GD, Lau TL, Tew DJ, Perez K, Wade JD, Bush AI, Drew SC, Separovic F, Masters CL, Cappai R, Barnham KJ. Copper-mediated Amyloid-β Toxicity Is Associated with an Intermolecular Histidine Bridge. J Biol Chem 2006; 281:15145-54. [PMID: 16595673 DOI: 10.1074/jbc.m600417200] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Amyloid-beta peptide (Abeta) is pivotal to the pathogenesis of Alzheimer disease. Here we report the formation of a toxic Abeta-Cu2+ complex formed via a histidine-bridged dimer, as observed at Cu2+/peptide ratios of >0.6:1 by EPR spectroscopy. The toxicity of the Abeta-Cu2+ complex to cultured primary cortical neurons was attenuated when either the pi -or tau-nitrogen of the imidazole side chains of His were methylated, thereby inhibiting formation of the His bridge. Toxicity did not correlate with the ability to form amyloid or perturb the acyl-chain region of a lipid membrane as measured by diphenyl-1,3,5-hexatriene anisotropy, but did correlate with lipid peroxidation and dityrosine formation. 31P magic angle spinning solid-state NMR showed that Abeta and Abeta-Cu2+ complexes interacted at the surface of a lipid membrane. These findings indicate that the generation of the Abeta toxic species is modulated by the Cu2+ concentration and the ability to form an intermolecular His bridge.
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Affiliation(s)
- David P Smith
- Department of Pathology, Centre for Neuroscience, and School of Chemistry, University of Melbourne, Victoria 3010, Australia
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Brazier MW, Lewis V, Ciccotosto GD, Klug GM, Lawson VA, Cappai R, Ironside JW, Masters CL, Hill AF, White AR, Collins S. Correlative studies support lipid peroxidation is linked to PrPres propagation as an early primary pathogenic event in prion disease. Brain Res Bull 2006; 68:346-54. [PMID: 16377442 DOI: 10.1016/j.brainresbull.2005.09.010] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2005] [Accepted: 09/20/2005] [Indexed: 11/29/2022]
Abstract
To assess whether heightened oxidative stress plays an early and primary pathogenic role in transmissible spongiform encephalopathies (TSE), we undertook detailed correlative studies using a mouse-adapted model of human disease. The spatio-temporal evolution of the abnormal, protease-resistant isoform of the prion protein (PrP(res)) and neuropathological changes were correlated with the occurrence and type of oxidative stress. Heightened oxidative stress was demonstrated, but restricted to elevated levels of free aldehydic breakdown products of lipid peroxidation, affecting all brain regions to varying extents. The increase in lipid peroxidation was highest over the mid-incubation period, with the onset showing close temporal and general topographical concordance with the first detection of PrP(res) with both pre-empting the typical neuropathological changes of spongiform change, gliosis and neuronal loss. Further, prion propagation over the disease course was assessed using murine bioassay. This revealed that the initial rapid increase in infectivity titres was contemporaneous with the abrupt onset and maximisation of lipid peroxidation. The present results are an important extension to previous studies, showing that heightened oxidative stress in the form of lipid peroxidation is likely to constitute an early primary pathogenic event in TSE, associated temporally with the integral disease processes of prion propagation and PrP(res) formation, and consistent with causal links between these events and subsequent typical neuropathological changes.
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Affiliation(s)
- Marcus W Brazier
- Department of Pathology, The University of Melbourne, Vic. 3010, Australia
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39
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Crouch PJ, Blake R, Duce JA, Ciccotosto GD, Li QX, Barnham KJ, Curtain CC, Cherny RA, Cappai R, Dyrks T, Masters CL, Trounce IA. Copper-dependent inhibition of human cytochrome c oxidase by a dimeric conformer of amyloid-beta1-42. J Neurosci 2005; 25:672-9. [PMID: 15659604 PMCID: PMC6725334 DOI: 10.1523/jneurosci.4276-04.2005] [Citation(s) in RCA: 271] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In studies of Alzheimer's disease pathogenesis there is an increasing focus on mechanisms of intracellular amyloid-beta (Abeta) generation and toxicity. Here we investigated the inhibitory potential of the 42 amino acid Abeta peptide (Abeta1-42) on activity of electron transport chain enzyme complexes in human mitochondria. We found that synthetic Abeta1-42 specifically inhibited the terminal complex cytochrome c oxidase (COX) in a dose-dependent manner that was dependent on the presence of Cu2+ and specific "aging" of the Abeta1-42 solution. Maximal COX inhibition occurred when using Abeta1-42 solutions aged for 3-6 h at 30 degrees C. The level of Abeta1-42-mediated COX inhibition increased with aging time up to approximately 6 h and then declined progressively with continued aging to 48 h. Photo-induced cross-linking of unmodified proteins followed by SDS-PAGE analysis revealed dimeric Abeta as the only Abeta species to provide significant temporal correlation with the observed COX inhibition. Analysis of brain and liver from an Alzheimer's model mouse (Tg2576) revealed abundant Abeta immunoreactivity within the brain mitochondria fraction. Our data indicate that endogenous Abeta is associated with brain mitochondria and that Abeta1-42, possibly in its dimeric conformation, is a potent inhibitor of COX, but only when in the presence of Cu2+. We conclude that Cu2+-dependent Abeta-mediated inhibition of COX may be an important contributor to the neurodegeneration process in Alzheimer's disease.
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Affiliation(s)
- Peter J Crouch
- Centre for Neuroscience, The University of Melbourne, Victoria 3010, Australia
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40
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Tickler AK, Smith DG, Ciccotosto GD, Tew DJ, Curtain CC, Carrington D, Masters CL, Bush AI, Cherny RA, Cappai R, Wade JD, Barnham KJ. Methylation of the Imidazole Side Chains of the Alzheimer Disease Amyloid-β Peptide Results in Abolition of Superoxide Dismutase-like Structures and Inhibition of Neurotoxicity. J Biol Chem 2005; 280:13355-63. [PMID: 15668252 DOI: 10.1074/jbc.m414178200] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The toxicity of the amyloid-beta peptide (Abeta) is thought to be responsible for the neurodegeneration associated with Alzheimer disease. Generation of hydrogen peroxide has been implicated as a key step in the toxic pathway. Abeta coordinates the redox active metal ion Cu2+ to catalytically generate H2O2. Structural studies on the interaction of Abeta with Cu have suggested that the coordination sphere about the Cu2+ resembles the active site of superoxide dismutase 1. To investigate the potential role for such structures in the toxicity of Abeta, two novel Abeta40 peptides, Abeta40(HistauMe) and Abeta40(HispiMe), have been prepared, in which the histidine residues 6, 13, and 14 have been substituted with modified histidines where either the pi- or tau-nitrogen of the imidazole side chain is methylated to prevent the formation of bridging histidine moieties. These modifications did not inhibit the ability of these peptides to form fibrils. However, the modified peptides were four times more effective at generating H2O2 than the native sequence. Despite the ability to generate more H2O2, these peptides were not neurotoxic. Whereas the modifications to the peptide altered the metal binding properties, they also inhibited the interaction between the peptides and cell surface membranes. This is consistent with the notion that Abeta-membrane interactions are important for neurotoxicity and that inhibiting these interactions has therapeutic potential.
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Affiliation(s)
- Anna K Tickler
- Howard Florey Institute of Medical Research, Victoria 3010, Australia
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41
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Cappai R, Cheng F, Ciccotosto GD, Needham BE, Masters CL, Multhaup G, Fransson LA, Mani K. The amyloid precursor protein (APP) of Alzheimer disease and its paralog, APLP2, modulate the Cu/Zn-Nitric Oxide-catalyzed degradation of glypican-1 heparan sulfate in vivo. J Biol Chem 2005; 280:13913-20. [PMID: 15677459 DOI: 10.1074/jbc.m409179200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Processing of the recycling proteoglycan glypican-1 involves the release of its heparan sulfate chains by copper ion- and nitric oxide-catalyzed ascorbate-triggered autodegradation. The Alzheimer disease amyloid precursor protein (APP) and its paralogue, the amyloid precursor-like protein 2 (APLP2), contain copper ion-, zinc ion-, and heparan sulfate-binding domains. We have investigated the possibility that APP and APLP2 regulate glypican-1 processing during endocytosis and recycling. By using cell-free biochemical experiments, confocal laser immunofluorescence microscopy, and flow cytometry of tissues and cells from wild-type and knock-out mice, we find that (a) APP and glypican-1 colocalize in perinuclear compartments of neuroblastoma cells, (b) ascorbate-triggered nitric oxidecatalyzed glypican-1 autodegradation is zinc ion-dependent in the same cells, (c) in cell-free experiments, APP but not APLP2 stimulates glypican-1 autodegradation in the presence of both Cu(II) and Zn(II) ions, whereas the Cu(I) form of APP and the Cu(II) and Cu(I) forms of APLP2 inhibit autodegradation, (d) in primary cortical neurons from APP or APLP2 knock-out mice, there is an increased nitric oxide-catalyzed degradation of heparan sulfate compared with brain tissue and neurons from wild-type mice, and (e) in growth-quiescent fibroblasts from APLP2 knock-out mice, but not from APP knock-out mice, there is also an increased heparan sulfate degradation. We propose that the rate of autoprocessing of glypican-1 is modulated by APP and APLP2 in neurons and by APLP2 in fibroblasts. These observation identify a functional relationship between the heparan sulfate and copper ion binding activities of APP/APLP2 in their modulation of the nitroxyl anion-catalyzed heparan sulfate degradation in glypican-1.
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Affiliation(s)
- Roberto Cappai
- Department of Pathology and Center for Neuroscience, The University of Melbourne, Victoria 3010, Australia
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42
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Bellingham SA, Ciccotosto GD, Needham BE, Fodero LR, White AR, Masters CL, Cappai R, Camakaris J. Gene knockout of amyloid precursor protein and amyloid precursor-like protein-2 increases cellular copper levels in primary mouse cortical neurons and embryonic fibroblasts. J Neurochem 2004; 91:423-8. [PMID: 15447675 DOI: 10.1111/j.1471-4159.2004.02731.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Alzheimer's disease is characterised by the accumulation of amyloid-beta peptide, which is cleaved from the copper-binding amyloid-beta precursor protein. Recent in vivo and in vitro studies have illustrated the importance of copper in Alzheimer's disease neuropathogenesis and suggested a role for amyloid-beta precursor protein and amyloid-beta in copper homeostasis. Amyloid-beta precursor protein is a member of a multigene family, including amyloid precursor-like proteins-1 and -2. The copper-binding domain is similar among amyloid-beta precursor protein family members, suggesting an overall conservation in its function or activity. Here, we demonstrate that double knockout of amyloid-beta precursor protein and amyloid precursor-like protein-2 expression results in significant increases in copper accumulation in mouse primary cortical neurons and embryonic fibroblasts. In contrast, over-expression of amyloid-beta precursor protein in transgenic mice results in significantly reduced copper levels in primary cortical neurons. These findings provide cellular neuronal evidence for the role of amyloid-beta precursor protein in copper homeostasis and support the existing hypothesis that amyloid-beta precursor protein and amyloid precursor-like protein-2 are copper-binding proteins with functionally interchangeable roles in copper homeostasis.
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43
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Ciccotosto GD, Tew D, Curtain CC, Smith D, Carrington D, Masters CL, Bush AI, Cherny RA, Cappai R, Barnham KJ. Enhanced toxicity and cellular binding of a modified amyloid beta peptide with a methionine to valine substitution. J Biol Chem 2004; 279:42528-34. [PMID: 15292164 DOI: 10.1074/jbc.m406465200] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The amyloid beta peptide (Abeta) is toxic to neuronal cells, and it is probable that this toxicity is responsible for the progressive cognitive decline associated with Alzheimer's disease. However, the nature of the toxic Abeta species and its precise mechanism of action remain to be determined. It has been reported that the methionine residue at position 35 has a pivotal role to play in the toxicity of Abeta. We examined the effect of mutating the methionine to valine in Abeta42 (AbetaM35V). The neurotoxic activity of AbetaM35V on primary mouse neuronal cortical cells was enhanced, and this diminished cell viability occurred at an accelerated rate compared with Abeta42. AbetaM35V binds Cu2+ and produces similar amounts of H2O2 as Abeta42 in vitro, and the neurotoxic activity was attenuated by the H2O2 scavenger catalase. The increased toxicity of AbetaM35V was associated with increased binding of this mutated peptide to cortical cells. The M35V mutation altered the interaction between Abeta and copper in a lipid environment as shown by EPR analysis, which indicated that the valine substitution made the peptide less rigid in the bilayer region with a resulting higher affinity for the bilayer. Circular dichroism spectroscopy showed that both Abeta42 and AbetaM35V displayed a mixture of alpha-helical and beta-sheet conformations. These findings provide further evidence that the toxicity of Abeta is regulated by binding to neuronal cells.
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44
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Barnham KJ, Haeffner F, Ciccotosto GD, Curtain CC, Tew D, Masters CL, Cherny RA, Cappai R, Bush AI. P4-241 The mechanism by which Aβ produces hydrogen peroxide and its role in neurotoxicity. Neurobiol Aging 2004. [DOI: 10.1016/s0197-4580(04)81799-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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45
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Barnham KJ, Haeffner F, Ciccotosto GD, Curtain CC, Tew D, Mavros C, Beyreuther K, Carrington D, Masters CL, Cherny RA, Cappai R, Bush AI. Tyrosine gated electron transfer is key to the toxic mechanism of Alzheimer's disease β‐amyloid. FASEB J 2004; 18:1427-9. [PMID: 15231727 DOI: 10.1096/fj.04-1890fje] [Citation(s) in RCA: 218] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Alzheimer's disease (AD) is characterized by the presence of neurofibrillary tangles and amyloid plaques, which are abnormal protein deposits. The major constituent of the plaques is the neurotoxic beta-amyloid peptide (Abeta); the genetics of familial AD support a direct role for this peptide in AD. Abeta neurotoxicity is linked to hydrogen peroxide formation. Abeta coordinates the redox active transition metals, copper and iron, to catalytically generate reactive oxygen species. The chemical mechanism underlying this process is not well defined. With the use of density functional theory calculations to delineate the chemical mechanisms that drive the catalytic production of H2O2 by Abeta/Cu, tyrosine10 (Y10) was identified as a pivotal residue for this reaction to proceed. The relative stability of tyrosyl radicals facilitates the electron transfers that are required to drive the reaction. Confirming the theoretical results, mutation of the tyrosine residue to alanine inhibited H2O2 production, Cu-induced radicalization, dityrosine cross-linking, and neurotoxicity.
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Affiliation(s)
- Kevin J Barnham
- Department of Pathology, University of Melbourne, Victoria, Australia.
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46
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Barnham KJ, Ciccotosto GD, Tickler AK, Ali FE, Smith DG, Williamson NA, Lam YH, Carrington D, Tew D, Kocak G, Volitakis I, Separovic F, Barrow CJ, Wade JD, Masters CL, Cherny RA, Curtain CC, Bush AI, Cappai R. Neurotoxic, redox-competent Alzheimer's beta-amyloid is released from lipid membrane by methionine oxidation. J Biol Chem 2003; 278:42959-65. [PMID: 12925530 DOI: 10.1074/jbc.m305494200] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The amyloid beta peptide is toxic to neurons, and it is believed that this toxicity plays a central role in the progression of Alzheimer's disease. The mechanism of this toxicity is contentious. Here we report that an Abeta peptide with the sulfur atom of Met-35 oxidized to a sulfoxide (Met(O)Abeta) is toxic to neuronal cells, and this toxicity is attenuated by the metal chelator clioquinol and completely rescued by catalase implicating the same toxicity mechanism as reduced Abeta. However, unlike the unoxidized peptide, Met(O)Abeta is unable to penetrate lipid membranes to form ion channel-like structures, and beta-sheet formation is inhibited, phenomena that are central to some theories for Abeta toxicity. Our results show that, like the unoxidized peptide, Met(O)Abeta will coordinate Cu2+ and reduce the oxidation state of the metal and still produce H2O2. We hypothesize that Met(O)Abeta production contributes to the elevation of soluble Abeta seen in the brain in Alzheimer's disease.
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Affiliation(s)
- Kevin J Barnham
- Department of Pathology, The University of Melbourne and The Mental Health Research Institute of Victoria, Victoria 3010, Australia.
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47
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Abstract
Menkes protein (ATP7A) is a P-type ATPase involved in copper uptake and homeostasis. Disturbed copper homeostasis occurs in patients with Menkes disease, an X-linked disorder characterized by mental retardation, neurodegeneration, connective tissue disorders, and early childhood death. Mutations in ATP7A result in malfunction of copper-requiring enzymes, such as tyrosinase and copper/zinc superoxide dismutase. The first step of the two-step amidation reaction carried out by peptidylglycine alpha-amidating monooxygenase (PAM) also requires copper. We used tissue from wild-type rats and mice and an ATP7A-specific antibody to determine that ATP7A is expressed at high levels in tissues expressing high levels of PAM. ATP7A is largely localized to the trans Golgi network in pituitary endocrine cells. The Atp7a mouse, bearing a mutation in the Atp7a gene, is an excellent model system for examining the consequences of ATP7A malfunction. Despite normal levels of PAM protein, levels of several amidated peptides were reduced in pituitary and brain extracts of Atp7a mice, demonstrating that PAM function is compromised when ATP7A is inactive. Based on these results, we conclude that a reduction in the ability of PAM to produce bioactive end-products involved in neuronal growth and development could contribute to many of the biological effects associated with Menkes disease.
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Affiliation(s)
- Tami C Steveson
- Department of Neuroscience,, University of Connecticut Health Center, Farmington, Connecticut 06030-3401, USA
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48
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Ciccotosto GD, Hand TA, Mains RE, Eipper BA. Breeding stock-specific variation in peptidylglycine alpha-amidating monooxygenase messenger ribonucleic acid splicing in rat pituitary. Endocrinology 2000; 141:476-86. [PMID: 10650926 DOI: 10.1210/endo.141.2.7337] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Peptidylglycine alpha-amidating monooxygenase (PAM) is a bifunctional enzyme that catalyzes the carboxyl-terminal amidation of glycine-extended peptides in a two-step reaction involving a monooxygenase and a lyase. Several forms of PAM messenger RNA result from alternative splicing of the single copy PAM gene. The presence of alternately spliced exon A between the two enzymatic domains allows endoproteolytic cleavage to occur in selected tissues, generating soluble monooxygenase and membrane lyase from integral membrane PAM. While using an exon A antiserum, we made the unexpected observation that Charles River Sprague Dawley rats expressed forms of PAM containing exon A in their pituitaries, whereas Harlan Sprague Dawley rats did not. Forms of PAM containing exon A were expressed in the atrium and hypothalamus of both types of Sprague Dawley rat, although in different proportions. PAM transmembrane domain splicing also differed between rat breeders, and full-length PAM-1 was not prevalent in the anterior pituitary of either type of rat. Despite striking differences in PAM splicing, no differences in levels of monooxygenase or lyase activity were observed in tissue or serum samples. The splicing patterns of other alternatively spliced genes, pituitary adenylate cyclase-activating polypeptide receptor type 1 and cardiac troponin T, did not vary with rat breeder. Strain-specific variations in the splicing of transcripts such as PAM must be taken into account in analyzing the resultant proteins, and knowledge of these differences should identify variations with functional significance.
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Affiliation(s)
- G D Ciccotosto
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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49
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Ciccotosto GD, Schiller MR, Eipper BA, Mains RE. Induction of integral membrane PAM expression in AtT-20 cells alters the storage and trafficking of POMC and PC1. J Cell Biol 1999; 144:459-71. [PMID: 9971741 PMCID: PMC2132922 DOI: 10.1083/jcb.144.3.459] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/1998] [Revised: 01/04/1999] [Indexed: 11/25/2022] Open
Abstract
Peptidylglycine alpha-amidating monooxygenase (PAM) is an essential enzyme that catalyzes the COOH-terminal amidation of many neuroendocrine peptides. The bifunctional PAM protein contains an NH2-terminal monooxygenase (PHM) domain followed by a lyase (PAL) domain and a transmembrane domain. The cytosolic tail of PAM interacts with proteins that can affect cytoskeletal organization. A reverse tetracycline-regulated inducible expression system was used to construct an AtT-20 corticotrope cell line capable of inducible PAM-1 expression. Upon induction, cells displayed a time- and dose-dependent increase in enzyme activity, PAM mRNA, and protein. Induction of increased PAM-1 expression produced graded changes in PAM-1 metabolism. Increased expression of PAM-1 also caused decreased immunofluorescent staining for ACTH, a product of proopiomelanocortin (POMC), and prohormone convertase 1 (PC1) in granules at the tips of processes. Expression of PAM-1 resulted in decreased ACTH and PHM secretion in response to secretagogue stimulation, and decreased cleavage of PC1, POMC, and PAM. Increased expression of a soluble form of PAM did not alter POMC and PC1 localization and metabolism. Using the inducible cell line model, we show that expression of integral membrane PAM alters the organization of the actin cytoskeleton. Altered cytoskeletal organization may then influence the trafficking and cleavage of lumenal proteins and eliminate the ability of AtT-20 cells to secrete ACTH in response to a secretagogue.
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Affiliation(s)
- G D Ciccotosto
- Departments of Neuroscience and Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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50
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Hollande F, Imdahl A, Mantamadiotis T, Ciccotosto GD, Shulkes A, Baldwin GS. Glycine-extended gastrin acts as an autocrine growth factor in a nontransformed colon cell line. Gastroenterology 1997; 113:1576-88. [PMID: 9352860 DOI: 10.1053/gast.1997.v113.pm9352860] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND & AIMS The hypothesis that progastrin-derived peptides act as autocrine growth factors for colorectal carcinomas has generated considerable interest. However, the influence of autocrine gastrins on nontumorigenic colonic cells has not been investigated. This study tested the above hypothesis in the nontumorigenic, conditionally immortalized mouse colon cell line YAMC. METHODS The effects of expression of antisense or sense gastrin messenger RNA, treatment with antibodies against progastrin-derived peptides, or treatment with gastrin receptor antagonists on YAMC cell proliferation were measured. RESULTS YAMC clones expressing antisense gastrin messenger RNA had reduced levels of immunoreactive progastrin-derived peptides and a reduced rate of proliferation, relative to vector only-transfected cells. Glycine-extended gastrin17, but not amidated gastrin17, reversed the antisense-induced inhibition of proliferation and stimulated the proliferation of sense- or vector only-transfected cells. YAMC cells bound 125I-glycine-extended gastrin17 (Kd, 0.36 nmol/L, 1810 sites/cell), but not 125I-amidated gastrin17, and binding was unaffected by gastrin receptor antagonists including benzotript. Proliferation of all YAMC clones was partially inhibited either by an antibody selective for glycine-extended gastrin or by preincubation with benzotript, and the inhibitory effects were additive. CONCLUSIONS YAMC cells use nonamidated progastrin-derived peptides as autocrine growth factors, partly through binding to an extracellular receptor selective for glycine-extended gastrin, and partly through an intracellular mechanism.
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Affiliation(s)
- F Hollande
- Department of Surgery, Austin Campus, Austin & Repatriation Medical Centre, Melbourne, Victoria, Australia
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