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Lizama BN, Williams C, North HA, Pandey K, Duong D, Di Caro V, Mecca AP, Blennow K, Zetterberg H, Levey AI, Grundman M, van Dyck CH, Caggiano AO, Seyfried NT, Hamby ME. CT1812 biomarker signature from a meta-analysis of CSF proteomic findings from two Phase 2 clinical trials in Alzheimer's disease. Alzheimers Dement 2024. [PMID: 39166791 DOI: 10.1002/alz.14152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 06/26/2024] [Accepted: 07/02/2024] [Indexed: 08/23/2024]
Abstract
INTRODUCTION CT1812 is in clinical development for the treatment of Alzheimer's disease (AD). Cerebrospinal fluid (CSF) exploratory proteomics was employed to identify pharmacodynamic biomarkers of CT1812 in mild to moderate AD from two independent clinical trials. METHODS Unbiased analysis of tandem-mass tag mass spectrometry (TMT-MS) quantitative proteomics, pathway analysis and correlation analyses with volumetric magnetic resonance imaging (vMRI) were performed for the SPARC cohort (NCT03493282). Comparative analyses and a meta-analysis with the interim SHINE cohort (NCT03507790; SHINE-A) followed by network analysis (weighted gene co-expression network analysis [WGCNA]) were used to understand the biological impact of CT1812. RESULTS CT1812 pharmacodynamic biomarkers and biological pathways were identified that replicate across two clinical cohorts. The meta-analysis revealed novel candidate biomarkers linked to S2R biology and AD, and network analysis revealed treatment-associated networks driven by S2R. DISCUSSION: Early clinical validation of CT1812 candidate biomarkers replicating in independent cohorts strengthens the understanding of the biological impact of CT1812 in patients with AD, and supports CT1812's synaptoprotective mechanism of action and its continued clinical development. HIGHLIGHTS This exploratory proteomics study identified candidate biomarkers of CT1812 in SPARC (NCT03493282) Comparative analyses identified biomarkers replicating across trials/cohorts Two independent Ph2 trial cohorts (SPARC and interim SHINE [NCT03507790; SHINE-A]) were used in a meta-analysis Amyloid beta (Aβ) & synaptic biology impacted by CT1812 and volumetric magnetic resonance imaging (vMRI) treatment-related correlates emerge Network analyses revealed sigma-2 receptor (S2R)-interacting proteins that may be "drivers" of changes.
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Affiliation(s)
| | | | | | - Kiran Pandey
- Emtherapro Inc, Systems Biology, Atlanta, Georgia, USA
| | - Duc Duong
- Emory University School of Medicine, Biochemistry, Atlanta, Georgia, USA
| | | | - Adam P Mecca
- Department of Psychiatry, Alzheimer's Disease Research Unit, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kaj Blennow
- Paris Brain Institute, ICM, Pitié-Salpêtrière Hospital, Sorbonne University, Paris, France
- Neurodegenerative Disorder Research Center, Division of Life Sciences and Medicine, and Department of Neurology, Institute on Aging and Brain Disorders, University of Science and Technology of China and First Affiliated Hospital of USTC, Hefei, Anhui, P.R. China
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Göteborg, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Göteborg, Sweden
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Göteborg, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Göteborg, Sweden
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK
- UK Dementia Research Institute at UCL, London, UK
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
- Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Allan I Levey
- Emory University School of Medicine, Neurology, Atlanta, Georgia, USA
| | - Michael Grundman
- Global R&D Partners, LLC, San Diego, California, USA
- Dept. of Neurosciences, University of California, San Diego, California, USA
| | - Christopher H van Dyck
- Department of Psychiatry, Alzheimer's Disease Research Unit, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | | | - Mary E Hamby
- Cognition Therapeutics, Pittsburgh, Pennsylvania, USA
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Cheng F, Fransson LÅ, Mani K. Interplay between glypican-1, amyloid-β and tau phosphorylation in human neural stem cells. Neuroscience 2024; 553:121-127. [PMID: 38992568 DOI: 10.1016/j.neuroscience.2024.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2024] [Revised: 06/19/2024] [Accepted: 07/04/2024] [Indexed: 07/13/2024]
Abstract
INTRODUCTION Alzheimer's disease (AD) is characterized by accumulation of amyloid beta (Aβ) and hyperphosphorylated tau (Tau-P) in the brain. Aβ enhances the activity of kinases involved in the formation of Tau-P. Phosphorylation at Thr 181 determines the propagation of multiple tau phosphorylations. Aβ is derived from the amyloid precursor protein (APP). Cleavage of APP by β-secretase also initiates release of heparan sulfate (HS) from the proteoglycan glypican-1 (GPC1). OBJECTIVES In this study, we have explored possible connections between GPC1 expression, HS release, APP processing and Tau-P formation in human neural stem cells. METHODS GPC1 formation was suppressed by using CRISPR/Cas9 and increased by using a vector encoding GPC1. HS release from GPC1 was increased by growing cells in medium containing Arg and ascorbate. Effects were monitored by immunofluorescence microscopy and slot immunoblotting using antibodies/antisera recognizing Aβ, GPC1, HS released from GPC1, total Tau, and Tau phosphorylated at Thr-181, 217 or 231. The latter have been used as blood biomarkers for AD. RESULTS Suppression of GPC1 expression resulted in increased phosphorylation at Thr 181 and Thr 217. When GPC1 was overexpressed, phosphorylation at Thr 217 decreased. Stimulation of HS release from GPC1 diminished tau phosphorylation at all of the three Thr positions, while expression of GPC1 was unaffected. Simultaneous stimulation of HS release and APP processing by the cytokine TNF-α also suppressed tau phosphorylation. CONCLUSION The increased release of GPC1-derived HS may interfere with Aβ formation and/or Aβ interaction with tau.
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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
| | - Lars-Åke Fransson
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, Biomedical Center A13, SE-221 84 Lund, Sweden
| | - Katrin Mani
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, Biomedical Center A13, SE-221 84 Lund, Sweden.
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Mani K. Isolation and Characterization of Heparan Sulfate Containing Amyloid Precursor Protein Degradation Products. Methods Mol Biol 2022; 2303:279-288. [PMID: 34626386 DOI: 10.1007/978-1-0716-1398-6_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Numerous studies indicate that heparan sulfate proteoglycans (HSPGs) participate in a network of complex molecular events involving amyloid precursor protein (APP) processing and formation, oligomerization, intracellular targeting, clearance, and propagation of amyloid β in Alzheimer's disease (AD). A mutual functional interplay between recycling glypican-1 and APP processing has been demonstrated where the HS released from glypican-1 by a Cu/NO-ascorbate-dependent reaction forms a conjugate with APP degradation products and undergoes an endosome-nucleus-autophagosome co-trafficking. HS has been shown to display contradictory and dual effects in AD involving both prevention and promotion of amyloid β formation. It is therefore important to identify the source, detailed structural features as well as factors that favor formation of the neuroprotective forms of HS. Here, a method for isolation and identification of HS-containing APP degradation products has been described. The method is based on isolation of radiolabeled HS followed by identification of accompanying APP degradation products by SDS-PAGE and Western blotting.
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Affiliation(s)
- Katrin Mani
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, Lund, Sweden.
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Cheng F, Fransson LÅ, Mani K. Proinflammatory cytokines induce accumulation of glypican-1-derived heparan sulfate and the C-terminal fragment of β-cleaved APP in autophagosomes of dividing neuronal cells. Glycobiology 2020; 30:539-549. [PMID: 32039447 PMCID: PMC7372925 DOI: 10.1093/glycob/cwaa011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 01/12/2020] [Accepted: 01/30/2020] [Indexed: 12/17/2022] Open
Abstract
Proinflammatory cytokines stimulate expression of β-secretase, which increases processing of amyloid precursor protein (APP), ultimately leading to the deposition of amyloid beta (Aβ). The N-terminal domain of β-cleaved APP supports Cu/NO-dependent release of heparan sulfate (HS) from the glypican-1 (Gpc-1) proteoglycan. HS is an inhibitor of β-secretase, thereby constituting a regulatory, negative feedback loop. Here, we have investigated the effect of the proinflammatory cytokines TNF-α, IL-1β and IL-6 on the interplay between APP processing and release of HS from Gpc-1 in neuronal cells. We have used deconvolution immunofluorescence microscopy and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and a panel of monoclonal/polyclonal antibodies recognizing the released HS, the N-terminus of Aβ, Aβ, the C-terminus of APP and the autophagosome marker LC3 as well as the chemical lysosome marker LysoTrackerRed (LTR). We repeatedly found that N2a neuroblastoma cells and human neural stem cells grown in the presence of the cytokines developed large cytoplasmic clusters, which stained positive for HS, the N-terminus of Aβ, Aβ, the C-terminus of APP, LC3 and LTR, indicating accumulation of HS and APP/APP degradation products in enlarged autophagosomes/lysosomes. The SDS-PAGE of immunoisolates obtained from TNF-α-treated N2a cells by using anti-C-terminus of APP revealed the presence of SDS-stable complexes between HS and the C-terminal fragment of β-cleaved APP (βCTF) migrating in the range 10-18 kDa. Clustered accumulation of βCTF disappeared when HS release was prevented and slightly enhanced when HS release was increased. Hence, when proinflammatory cytokines induce increased processing of APP, inhibition of β-secretase by HS is insufficient, which may lead to the impaired autophagosomal degradation.
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Affiliation(s)
- Fang Cheng
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, 221 00 Lund, Sweden
| | - Lars-Åke Fransson
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, 221 00 Lund, Sweden
| | - Katrin Mani
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, 221 00 Lund, Sweden
- To whom correspondence should be addressed: Tel: +46-46-222-4044; e-mail:
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Wang S, Qiu Y, Bai B. The Expression, Regulation, and Biomarker Potential of Glypican-1 in Cancer. Front Oncol 2019; 9:614. [PMID: 31355137 PMCID: PMC6640540 DOI: 10.3389/fonc.2019.00614] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 06/21/2019] [Indexed: 12/31/2022] Open
Abstract
Glypican-1 (GPC-1) and other glypicans are a family of heparan sulfate proteoglycans. These proteins are highly expressed on the cell membrane and in the extracellular matrix, functioning mainly as modulators of growth factor signaling. Some of them are abnormally expressed in cancer, possibly involved in tumorigenesis, and detectable in blood as potential clinical biomarkers. GPC-1 is another glypican member that has been found to be associated with some cancers, and has increasingly interested the cancer field. Here we provide a brief review about GPC-1 in its expression, signaling and potential as a cancer biomarker.
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Affiliation(s)
- Sen Wang
- Department of Clinical Laboratory Medicine, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Yudong Qiu
- Department of Hepatopancreatobiliary Surgery, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Bing Bai
- Department of Clinical Laboratory Medicine, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
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The cyanobacterial neurotoxin β-N-methylamino-l-alanine prevents addition of heparan sulfate to glypican-1 and increases processing of amyloid precursor protein in dividing neuronal cells. Exp Cell Res 2019; 379:172-181. [DOI: 10.1016/j.yexcr.2019.03.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/27/2019] [Accepted: 03/30/2019] [Indexed: 12/20/2022]
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Young TR, Wedd AG, Xiao Z. Evaluation of Cu(i) binding to the E2 domain of the amyloid precursor protein - a lesson in quantification of metal binding to proteins via ligand competition. Metallomics 2019; 10:108-119. [PMID: 29215101 DOI: 10.1039/c7mt00291b] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The extracellular domain E2 of the amyloid precursor protein (APP) features a His-rich metal-binding site (denoted as the M1 site). In conjunction with surrounding basic residues, the site participates in interactions with components of the extracellular matrix including heparins, a class of negatively charged polysaccharide molecules of varying length. This work studied the chemistry of Cu(i) binding to APP E2 with the probe ligands Bcs, Bca, Fz and Fs. APP E2 forms a stable Cu(i)-mediated ternary complex with each of these anionic ligands. The complex with Bca was selected for isolation and characterization and was demonstrated, by native ESI-MS analysis, to have the stoichiometry E2 : Cu(i) : Bca = 1 : 1 : 1. Formation of these ternary complexes is specific for the APP E2 domain and requires Cu(i) coordination to the M1 site. Mutation of the M1 site was consistent with the His ligands being part of the E2 ligand set. It is likely that interactions between the negatively charged probe ligands and a positively charged patch on the surface of APP E2 are one aspect of the generation of the stable ternary complexes. Their formation prevented meaningful quantification of the affinity of Cu(i) binding to the M1 site with these probe ligands. However, the ternary complexes are disrupted by heparin, allowing reliable determination of a picomolar Cu(i) affinity for the E2/heparin complex with the Fz or Bca probe ligands. This is the first documented example of the formation of stable ternary complexes between a Cu(i) binding protein and a probe ligand. The ready disruption of the complexes by heparin identified clear 'tell-tale' signs for diagnosis of ternary complex formation and allowed a systematic review of conditions and criteria for reliable determination of affinities for metal binding via ligand competition. This study also provides new insights into a potential correlation of APP functions regulated by copper binding and heparin interaction.
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Affiliation(s)
- Tessa R Young
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
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Dai Y, Abbasi K, DePietro M, Butler S, Liu CC. Advanced fabrication of biosensor on detection of Glypican-1 using S-Acetylmercaptosuccinic anhydride (SAMSA) modification of antibody. Sci Rep 2018; 8:13541. [PMID: 30202003 PMCID: PMC6131508 DOI: 10.1038/s41598-018-31994-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 08/28/2018] [Indexed: 12/23/2022] Open
Abstract
Glypican-1 (GPC-1) has been recognized as biomarker of pancreatic cancer. Quantification of GPC-1 level is also pivotal to breast cancer and prostate cancer’s patients. We hereby report the first biosensor for GPC-1 detection. Instead of using crosslinking technique and surface immobilization of antibody, we applied a novel method for biosensor fabrication, using S-Acetylmercaptosuccinic anhydride (SAMSA) to modify the Anti-GPC-1 producing a thiol-linked Anti-GPC-1. The thiol-linked Anti-GPC-1 was then directly formed a single-layer antibody layer on the gold biosensor, minimizing the biosensor preparation steps significantly. Time of Flight Secondary Ions Mass Spectroscopy (TOF-SIMS) characterization verified the thiol-linked antibody layer and demonstrated a unique perspective for surface protein characterization. Differential pulse voltammetry (DPV) was applied to quantify GPC-1 antigen in undiluted human serum with a concentration range of 5,000 pg/µL to 100 pg/µL. The performance of this newly designed biosensor was also compared with modified self-assembled monolayer system fabricated biosensor, demonstrating the high-sensitivity and high-reproducibility of the SAMSA modified antibody based biosensor. This simple fabrication method can also expand to detection of other biomolecules. The simplified operation process shows great potential in clinical application development.
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Affiliation(s)
- Yifan Dai
- Department of Chemical and Biomolecular Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, USA.,Electronics Design Center, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, USA
| | - Kevin Abbasi
- Swagelok Center for Surface Analysis of Materials (SCSAM), Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, USA
| | - Michael DePietro
- Department of Chemical and Biomolecular Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, USA
| | - Samantha Butler
- Department of Chemical and Biomolecular Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, USA
| | - Chung Chiun Liu
- Department of Chemical and Biomolecular Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, USA. .,Electronics Design Center, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, USA.
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9
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Young TR, Pukala TL, Cappai R, Wedd AG, Xiao Z. The Human Amyloid Precursor Protein Binds Copper Ions Dominated by a Picomolar-Affinity Site in the Helix-Rich E2 Domain. Biochemistry 2018; 57:4165-4176. [DOI: 10.1021/acs.biochem.8b00572] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Tessa R. Young
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Tara L. Pukala
- Discipline of Chemistry, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Roberto Cappai
- Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Anthony G. Wedd
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Zhiguang Xiao
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
- Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3052, Australia
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Levin RA, Lund ME, Truong Q, Wu A, Shore ND, Saltzstein DR, Concepcion RS, Paivanas TA, van Breda A, Beebe-Dimmer J, Ruterbusch JJ, Wissmueller S, Campbell DH, Walsh BJ. Development of a reliable assay to measure glypican-1 in plasma and serum reveals circulating glypican-1 as a novel prostate cancer biomarker. Oncotarget 2018; 9:22359-22367. [PMID: 29854284 PMCID: PMC5976470 DOI: 10.18632/oncotarget.25009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 03/11/2018] [Indexed: 12/20/2022] Open
Abstract
Prostate cancer is responsible for hundreds of thousands of annual deaths worldwide. The current gold standard in early detection of prostate cancer, the prostate specific antigen test, boasts a high sensitivity but low specificity, resulting in many unnecessary prostate biopsies. Thus, emphasis has been placed on identifying new biomarkers to improve prostate cancer detection. Glypican-1 has recently been proposed as one such biomarker, however further exploration into its predictive power has been hindered by a lack of available, dependable glypican-1 immunoassays. Previously, we identified human glypican-1 as the antigenic target of the MIL-38 monoclonal antibody. Additionally, we have now generated another monoclonal antibody, 3G5, that also recognizes human glypican-1. Here we report the development of a reliable, custom Luminex® assay that enables precise quantitation of circulating human glypican-1 in plasma and serum. Using this assay, we show for the first time that circulating glypican-1 levels can differentiate non-cancer (normal and benign prostatic hyperplasia) patients from prostate cancer patients, as well as benign prostatic hyperplasia patients alone from prostate cancer patients. Our findings strongly promote future investigation into the use of glypican-1 for early detection of prostate cancer.
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Affiliation(s)
- Rachel A Levin
- Minomic International Ltd, Sydney, New South Wales, Australia
| | - Maria E Lund
- Minomic International Ltd, Sydney, New South Wales, Australia
| | - Quach Truong
- Minomic International Ltd, Sydney, New South Wales, Australia
| | - Angela Wu
- Minomic International Ltd, Sydney, New South Wales, Australia
| | - Neal D Shore
- CUSP LLC Research Consortium, Annandale, VA, USA
| | | | | | | | | | - Jennifer Beebe-Dimmer
- Barbara Ann Karmanos Cancer Institute and Wayne State University, School of Medicine, Department of Oncology, Detroit, MI, USA
| | - Julie J Ruterbusch
- Barbara Ann Karmanos Cancer Institute and Wayne State University, School of Medicine, Department of Oncology, Detroit, MI, USA
| | | | | | - Bradley J Walsh
- Minomic International Ltd, Sydney, New South Wales, Australia
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Amyloid precursor protein and amyloid precursor-like protein 2 in cancer. Oncotarget 2017; 7:19430-44. [PMID: 26840089 PMCID: PMC4991393 DOI: 10.18632/oncotarget.7103] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 01/23/2016] [Indexed: 12/22/2022] Open
Abstract
Amyloid precursor protein (APP) and its family members amyloid precursor-like protein 1 (APLP1) and amyloid precursor-like protein 2 (APLP2) are type 1 transmembrane glycoproteins that are highly conserved across species. The transcriptional regulation of APP and APLP2 is similar but not identical, and the cleavage of both proteins is regulated by phosphorylation. APP has been implicated in Alzheimer's disease causation, and in addition to its importance in neurology, APP is deregulated in cancer cells. APLP2 is likewise overexpressed in cancer cells, and APLP2 and APP are linked to increased tumor cell proliferation, migration, and invasion. In this present review, we discuss the unfolding account of these APP family members’ roles in cancer progression and metastasis.
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Cytochrome b561, copper, β-cleaved amyloid precursor protein and niemann-pick C1 protein are involved in ascorbate-induced release and membrane penetration of heparan sulfate from endosomal S-nitrosylated glypican-1. Exp Cell Res 2017; 360:171-179. [DOI: 10.1016/j.yexcr.2017.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 08/30/2017] [Accepted: 09/01/2017] [Indexed: 11/21/2022]
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Piacentini R, Puma DDL, Mainardi M, Lazzarino G, Tavazzi B, Arancio O, Grassi C. Reduced gliotransmitter release from astrocytes mediates tau-induced synaptic dysfunction in cultured hippocampal neurons. Glia 2017; 65:1302-1316. [PMID: 28519902 PMCID: PMC5520670 DOI: 10.1002/glia.23163] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/13/2017] [Accepted: 04/18/2017] [Indexed: 01/19/2023]
Abstract
Tau is a microtubule-associated protein exerting several physiological functions in neurons. In Alzheimer's disease (AD) misfolded tau accumulates intraneuronally and leads to axonal degeneration. However, tau has also been found in the extracellular medium. Recent studies indicated that extracellular tau uploaded from neurons causes synaptic dysfunction and contributes to tau pathology propagation. Here we report novel evidence that extracellular tau oligomers are abundantly and rapidly accumulated in astrocytes where they disrupt intracellular Ca2+ signaling and Ca2+ -dependent release of gliotransmitters, especially ATP. Consequently, synaptic vesicle release, the expression of pre- and postsynaptic proteins, and mEPSC frequency and amplitude were reduced in neighboring neurons. Notably, we found that tau uploading from astrocytes required the amyloid precursor protein, APP. Collectively, our findings suggests that astrocytes play a critical role in the synaptotoxic effects of tau via reduced gliotransmitter availability, and that astrocytes are major determinants of tau pathology in AD.
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Affiliation(s)
- Roberto Piacentini
- Institute of Human Physiology, Medical School, Università Cattolica, Largo F. Vito 1, 00168, Rome, Italy
| | - Domenica Donatella Li Puma
- Institute of Human Physiology, Medical School, Università Cattolica, Largo F. Vito 1, 00168, Rome, Italy
| | - Marco Mainardi
- Institute of Human Physiology, Medical School, Università Cattolica, Largo F. Vito 1, 00168, Rome, Italy
| | - Giacomo Lazzarino
- Institute of Biochemistry and Clinical Biochemistry, Medical School, Università Cattolica, Largo F. Vito 1, 00168, Rome, Italy
| | - Barbara Tavazzi
- Institute of Biochemistry and Clinical Biochemistry, Medical School, Università Cattolica, Largo F. Vito 1, 00168, Rome, Italy
| | - Ottavio Arancio
- Department of Pathology and Cell Biology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, 630 W 168th St., NY 10032 USA
| | - Claudio Grassi
- Institute of Human Physiology, Medical School, Università Cattolica, Largo F. Vito 1, 00168, Rome, Italy
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Puzzo D, Piacentini R, Fá M, Gulisano W, Li Puma DD, Staniszewski A, Zhang H, Tropea MR, Cocco S, Palmeri A, Fraser P, D'Adamio L, Grassi C, Arancio O. LTP and memory impairment caused by extracellular Aβ and Tau oligomers is APP-dependent. eLife 2017; 6. [PMID: 28696204 PMCID: PMC5529106 DOI: 10.7554/elife.26991] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/10/2017] [Indexed: 12/21/2022] Open
Abstract
The concurrent application of subtoxic doses of soluble oligomeric forms of human amyloid-beta (oAβ) and Tau (oTau) proteins impairs memory and its electrophysiological surrogate long-term potentiation (LTP), effects that may be mediated by intra-neuronal oligomers uptake. Intrigued by these findings, we investigated whether oAβ and oTau share a common mechanism when they impair memory and LTP in mice. We found that as already shown for oAβ, also oTau can bind to amyloid precursor protein (APP). Moreover, efficient intra-neuronal uptake of oAβ and oTau requires expression of APP. Finally, the toxic effect of both extracellular oAβ and oTau on memory and LTP is dependent upon APP since APP-KO mice were resistant to oAβ- and oTau-induced defects in spatial/associative memory and LTP. Thus, APP might serve as a common therapeutic target against Alzheimer's Disease (AD) and a host of other neurodegenerative diseases characterized by abnormal levels of Aβ and/or Tau. DOI:http://dx.doi.org/10.7554/eLife.26991.001
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Affiliation(s)
- Daniela Puzzo
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Roberto Piacentini
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Mauro Fá
- Department of Pathology and Cell Biology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, United States
| | - Walter Gulisano
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Domenica D Li Puma
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Agnes Staniszewski
- Department of Pathology and Cell Biology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, United States
| | - Hong Zhang
- Department of Pathology and Cell Biology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, United States
| | - Maria Rosaria Tropea
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Sara Cocco
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Agostino Palmeri
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Paul Fraser
- Tanz Centre for Research in Neurodegenerative Diseases and Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | - Luciano D'Adamio
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, United States
| | - Claudio Grassi
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Ottavio Arancio
- Department of Pathology and Cell Biology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New york, United States
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15
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Cheng F, Belting M, Fransson LÅ, Mani K. Nucleolin is a nuclear target of heparan sulfate derived from glypican-1. Exp Cell Res 2017; 354:31-39. [PMID: 28300561 DOI: 10.1016/j.yexcr.2017.03.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 12/11/2022]
Abstract
The recycling, S-nitrosylated heparan sulfate (HS) proteoglycan glypican-1 releases anhydromannose (anMan)-containing HS chains by a nitrosothiol-catalyzed cleavage in endosomes that can be constitutive or induced by ascorbate. The HS-anMan chains are then transported to the nucleus. A specific nuclear target for HS-anMan has not been identified. We have monitored endosome-to-nucleus trafficking of HS-anMan by deconvolution and confocal immunofluorescence microscopy using an anMan-specific monoclonal antibody in non-growing, ascorbate-treated, and growing, untreated, wild-type mouse embryonic fibroblasts and hypoxia-exposed Alzheimer mouse Tg2576 fibroblasts and human U87 glioblastoma cells. In all cells, nuclear HS-anMan targeted a limited number of sites of variable size where it colocalized with DNA and nucleolin, an established marker for nucleoli. HS-anMan also colocalized with ethynyl uridine-tagged nascent RNA and two acetylated forms of histone H3. Acute hypoxia increased the formation of HS-anMan in both Tg2576 and U87 cells. A portion of HS-anMan colocalized with nucleolin at small discrete sites, while most of the nucleolin and nascent RNA was dispersed. In U87 cells, HS-anMan, nucleolin and nascent RNA reassembled after prolonged hypoxia. Nucleolar HS may modulate synthesis and/or release of rRNA.
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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
| | - Mattias Belting
- Department of Clinical Sciences, Section of Oncology and Pathology, Lund University, Lund, Sweden
| | - Lars-Åke Fransson
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, Biomedical Center A13, SE-221 84 Lund, Sweden
| | - Katrin Mani
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, Biomedical Center A13, SE-221 84 Lund, Sweden.
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16
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Role of Matricellular Proteins in Disorders of the Central Nervous System. Neurochem Res 2016; 42:858-875. [DOI: 10.1007/s11064-016-2088-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 10/17/2016] [Accepted: 10/21/2016] [Indexed: 12/15/2022]
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17
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Plummer S, Van den Heuvel C, Thornton E, Corrigan F, Cappai R. The Neuroprotective Properties of the Amyloid Precursor Protein Following Traumatic Brain Injury. Aging Dis 2016; 7:163-79. [PMID: 27114849 PMCID: PMC4809608 DOI: 10.14336/ad.2015.0907] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 09/07/2015] [Indexed: 01/16/2023] Open
Abstract
Despite the significant health and economic burden that traumatic brain injury (TBI) places on society, the development of successful therapeutic agents have to date not translated into efficacious therapies in human clinical trials. Injury to the brain is ongoing after TBI, through a complex cascade of primary and secondary injury events, providing a valuable window of opportunity to help limit and prevent some of the severe consequences with a timely treatment. Of note, it has been suggested that novel treatments for TBI should be multifactorial in nature, mimicking the body's own endogenous repair response. Whilst research has historically focused on the role of the amyloid precursor protein (APP) in the pathogenesis of Alzheimer's disease, recent advances in trauma research have demonstrated that APP offers considerable neuroprotective properties following TBI, suggesting that APP is an ideal therapeutic candidate. Its acute upregulation following TBI has been shown to serve a beneficial role following trauma and has lead to significant advances in understanding the neuroprotective and neurotrophic functions of APP and its metabolites. Research has focused predominantly on the APP derivative sAPPα, which has consistently demonstrated neuroprotective and neurotrophic functions both in vitro and in vivo following various traumatic insults. Its neuroprotective activity has been narrowed down to a 15 amino acid sequence, and this region is linked to both heparan binding and growth-factor-like properties. It has been proposed that APP binds to heparan sulfate proteoglycans to exert its neuroprotective action. APP presents us with a novel therapeutic compound that could overcome many of the challenges that have stalled development of efficacious TBI treatments previously.
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Affiliation(s)
- Stephanie Plummer
- Adelaide Centre for Neuroscience Research, the University of Adelaide, South Australia, Australia
| | - Corinna Van den Heuvel
- Adelaide Centre for Neuroscience Research, the University of Adelaide, South Australia, Australia
| | - Emma Thornton
- Adelaide Centre for Neuroscience Research, the University of Adelaide, South Australia, Australia
| | - Frances Corrigan
- Adelaide Centre for Neuroscience Research, the University of Adelaide, South Australia, Australia
| | - Roberto Cappai
- Department of Pathology, the University of Melbourne, Victoria, Australia
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18
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Muñoz-Gutiérrez JF, Aguilar Pierlé S, Schneider DA, Baszler TV, Stanton JB. Transcriptomic Determinants of Scrapie Prion Propagation in Cultured Ovine Microglia. PLoS One 2016; 11:e0147727. [PMID: 26807844 PMCID: PMC4726464 DOI: 10.1371/journal.pone.0147727] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 01/07/2016] [Indexed: 12/22/2022] Open
Abstract
Susceptibility to infection by prions is highly dependent on the amino acid sequence and host expression of the cellular prion protein (PrPC); however, cellular expression of a genetically susceptible PrPC is insufficient. As an example, it has been shown in cultured cells that permissive and resistant sublines derived from the same parental population often have similar expression levels of PrPC. Thus, additional cellular factors must influence susceptibility to prion infection. The aim of this study was to elucidate the factors associated with relative permissiveness and resistance to scrapie prions in cultured cells derived from a naturally affected species. Two closely related ovine microglia clones with different prion susceptibility, but no detectable differences in PrPC expression levels, were inoculated with either scrapie-positive or scrapie-negative sheep brainstem homogenates. Five passages post-inoculation, the transcriptional profiles of mock and infected clones were sequenced using Illumina technology. Comparative transcriptional analyses identified twenty-two differentially transcribed genes, most of which were upregulated in poorly permissive microglia. This included genes encoding for selenoprotein P, endolysosomal proteases, and proteins involved in extracellular matrix remodeling. Furthermore, in highly permissive microglia, transforming growth factor β–induced, retinoic acid receptor response 1, and phosphoserine aminotranspherase 1 gene transcripts were upregulated. Gene Set Enrichment Analysis identified proteolysis, translation, and mitosis as the most affected pathways and supported the upregulation trend of several genes encoding for intracellular proteases and ribosomal proteins in poorly permissive microglia. This study identifies new genes potentially involved in scrapie prion propagation, corroborates results from other studies, and extends those results into another cell culture model.
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Affiliation(s)
- Juan F. Muñoz-Gutiérrez
- Department of Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
- * E-mail: (JFMG); (JBS)
| | - Sebastián Aguilar Pierlé
- Department of Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - David A. Schneider
- Department of Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
- United States Department of Agriculture, Agricultural Research Service, Pullman, Washington, United States of America
| | - Timothy V. Baszler
- Department of Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - James B. Stanton
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
- * E-mail: (JFMG); (JBS)
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19
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Cheng F, Bourseau-Guilmain E, Belting M, Fransson LÅ, Mani K. Hypoxia induces NO-dependent release of heparan sulfate in fibroblasts from the Alzheimer mouse Tg2576 by activation of nitrite reduction. Glycobiology 2016; 26:623-34. [DOI: 10.1093/glycob/cww007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 01/13/2016] [Indexed: 12/12/2022] Open
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20
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Urso E, Maffia M. Behind the Link between Copper and Angiogenesis: Established Mechanisms and an Overview on the Role of Vascular Copper Transport Systems. J Vasc Res 2015; 52:172-96. [PMID: 26484858 DOI: 10.1159/000438485] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 07/07/2015] [Indexed: 11/19/2022] Open
Abstract
Angiogenesis critically sustains the progression of both physiological and pathological processes. Copper behaves as an obligatory co-factor throughout the angiogenic signalling cascades, so much so that a deficiency causes neovascularization to abate. Moreover, the progress of several angiogenic pathologies (e.g. diabetes, cardiac hypertrophy and ischaemia) can be tracked by measuring serum copper levels, which are being increasingly investigated as a useful prognostic marker. Accordingly, the therapeutic modulation of body copper has been proven effective in rescuing the pathological angiogenic dysfunctions underlying several disease states. Vascular copper transport systems profoundly influence the activation and execution of angiogenesis, acting as multi-functional regulators of apparently discrete pro-angiogenic pathways. This review concerns the complex relationship among copper-dependent angiogenic factors, copper transporters and common pathological conditions, with an unusual accent on the multi-faceted involvement of the proteins handling vascular copper. Functions regulated by the major copper transport proteins (CTR1 importer, ATP7A efflux pump and metallo-chaperones) include the modulation of endothelial migration and vascular superoxide, known to activate angiogenesis within a narrow concentration range. The potential contribution of prion protein, a controversial regulator of copper homeostasis, is discussed, even though its angiogenic involvement seems to be mainly associated with the modulation of endothelial motility and permeability.
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Affiliation(s)
- Emanuela Urso
- Department of Biological and Environmental Science and Technologies, University of Salento, Lecce, Italy
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Suppression of glypican-1 autodegradation by NO-deprivation correlates with nuclear accumulation of amyloid beta in normal fibroblasts. Glycoconj J 2015; 32:675-84. [DOI: 10.1007/s10719-015-9616-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 08/10/2015] [Accepted: 08/12/2015] [Indexed: 11/25/2022]
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22
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Cheng F, Cappai R, Lidfeldt J, Belting M, Fransson LÅ, Mani K. Amyloid precursor protein (APP)/APP-like protein 2 (APLP2) expression is required to initiate endosome-nucleus-autophagosome trafficking of glypican-1-derived heparan sulfate. J Biol Chem 2015; 289:20871-8. [PMID: 24898256 DOI: 10.1074/jbc.m114.552810] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Anhydromannose (anMan)-containing heparan sulfate (HS) derived from the proteoglycan glypican-1 is generated in endosomes by an endogenously or ascorbate-induced S-nitrosothiolcatalyzed reaction. Processing of the amyloid precursor protein (APP) and APP-like protein 2 (APLP2) by β- and γ-secretases into amyloid β(A) and Aβ-like peptides also takes place in these compartments. Moreover, anMan-containing HS suppresses the formation of toxic Aβ assemblies in vitro. We showed by using deconvolution immunofluorescence microscopy with an anMan-specific monoclonal antibody as well as (35)S labeling experiments that expression of APP/APLP2 is required for ascorbate-induced transport of HS from endosomes to the nucleus. Nuclear translocation was observed in wild-type mouse embryonic fibroblasts (WT MEFs), Tg2576 MEFs, and N2a neuroblastoma cells but not in APP(-/-) and APLP2(-/-) MEFs. Transfection of APP(-/-) cells with a vector encoding APP restored nuclear import of anMan-containing HS. In WT MEFs and N2a neuroblastoma cells exposed to β- or γ-secretase inhibitors, nuclear translocation was greatly impeded, suggesting involvement of APP/APLP2 degradation products. In Tg2576 MEFs, the β-inhibitor blocked transport, but the γ-inhibitor did not. During chase in ascorbate- free medium, anMan-containing HS disappeared from the nuclei of WT MEFs. Confocal immunofluorescence microscopy showed that they appeared in acidic, LC3-positive vesicles in keeping with an autophagosomal location. There was increased accumulation of anMan-containing HS in nuclei and cytosolic vesicles upon treatment with chloroquine, indicating that HS was degraded in lysosomes. Manipulations of APP expression and processing may have deleterious effects upon HS function in the nucleus.
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23
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Cheng F, Fransson LÅ, Mani K. Rapid nuclear transit and impaired degradation of amyloid β and glypican-1-derived heparan sulfate in Tg2576 mouse fibroblasts. Glycobiology 2014; 25:548-56. [DOI: 10.1093/glycob/cwu185] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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24
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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] [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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25
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Analysis of the overall structure of the multi-domain amyloid precursor protein (APP). PLoS One 2013; 8:e81926. [PMID: 24324731 PMCID: PMC3852973 DOI: 10.1371/journal.pone.0081926] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 10/18/2013] [Indexed: 11/19/2022] Open
Abstract
The amyloid precursor protein (APP) and its processing by the α-, β- and γ-secretases is widely believed to play a central role during the development of Alzheimer´s disease. The three-dimensional structure of the entire protein, its physiologic function and the regulation of its proteolytic processing remain, however, largely unclear to date. To gain a deeper understanding of the structure of APP that underlies all of its functions, we first cloned and recombinantly expressed different constructs in E. coli. Using limited proteolysis followed by mass spectrometry and Edman degradation as well as analytical gel permeation chromatography coupled static light scattering, we experimentally analyzed the structural domain boundaries and determined that the large ectodomain of APP consists of exactly two rigidly folded domains - the E1-domain (Leu18-Ala190) and the E2-domain (Ser295-Asp500). Both, the acidic domain (AcD) connecting E1 and E2 as well as the juxtamembrane region (JMR) connecting E2 to the single transmembrane helix are highly flexible and extended. We identified in-between the E1-domain and the AcD an additional domain of conservation and partial flexibility that we termed extension domain (ED, Glu191-Glu227). Using Bio-layer interferometry, pull-down assays and analytical gel filtration experiments we demonstrated that the E1-domain does not tightly interact with the E2-domain, both in the presence and in the absence of heparin. APP hence forms an extended molecule that is flexibly tethered to the membrane. Its multi-domain architecture enables together with the many known functionalities the concomitant performance of several, independent functions, which might be regulated by cellular, compartment specific pH-changes.
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26
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Cheng F, Ruscher K, Fransson LÅ, Mani K. Non-toxic amyloid beta formed in the presence of glypican-1 or its deaminatively generated heparan sulfate degradation products. Glycobiology 2013; 23:1510-9. [PMID: 24026238 DOI: 10.1093/glycob/cwt079] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The amyloid beta (Aβ) peptides (mainly Aβ40 and Aβ42), which are derived from the amyloid precursor protein (APP), can oligomerize into antibody A11-positive, neurotoxic species, believed to be involved in Alzheimer's disease. Interestingly, APP binds strongly to the heparan sulfate (HS) proteoglycan (PG) glypican-1 (Gpc-1) in vitro and both proteins are colocalized inside cells. In endosomes, APP is proteolytically processed to yield Aβ peptides. The HS chains of S-nitrosylated (SNO) Gpc-1 PG are cleaved into anhydromannose (anMan)-containing di- and oligosaccharides by an NO-dependent reaction in the same compartments. Here, we have studied the toxicity of oligomers/aggregates of Aβ40 and Aβ42, as well as Aβ40/42 mixtures that were formed in the presence of immobilized Gpc-1 PG or immobilized HS oligosaccharides. Afterwards, Aβ was displaced from the matrices, analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and assayed for A11 immunoreactivity, for effects on growth of mouse N2a neuroblastoma cells and for membrane leakage in rat cortical neurons. HS generally promoted and accelerated Aβ multimerization into oligomers as well as larger aggregates that were mostly A11 positive and showed toxic effects. However, non-toxic Aβ was formed in the presence of Gpc-1 PG or when anMan-containing HS degradation products were simultaneously generated. Both toxic and non-toxic Aβ peptides were taken up by the cells but toxic forms appeared to enter the nuclei to a larger extent. The protection afforded by the presence of HS degradation products may reflect a normal intracellular function for the Aβ peptides.
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Affiliation(s)
- Fang Cheng
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group
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27
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Heparan Sulfate Subdomains that are Degraded by Sulf Accumulate in Cerebral Amyloid ß Plaques of Alzheimer's Disease. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:2056-67. [DOI: 10.1016/j.ajpath.2012.01.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 12/29/2011] [Accepted: 01/19/2012] [Indexed: 11/21/2022]
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28
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Chasseigneaux S, Allinquant B. Functions of Aβ, sAPPα and sAPPβ : similarities and differences. J Neurochem 2011; 120 Suppl 1:99-108. [PMID: 22150401 DOI: 10.1111/j.1471-4159.2011.07584.x] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Amyloid peptide (Aβ) is derived from the cleavage of amyloid precursor protein (APP), which also generates the soluble peptide APPβ (sAPPβ). An antagonist and major APP metabolic pathway involves cleavage by alpha secretase, which releases sAPPα. Although soluble Aβ oligomers are neurotoxic, Aβ monomers share similar properties with sAPPα. These include neurotrophic and neuroprotective effects, as well as stimulation of neural-progenitor proliferation. The properties of Aβ monomers and the neurotrophic capacity of sAPPβ to stimulate axonal outgrowth suggest that Aβ production is not deleterious per se. Consequently, therapeutic strategies for Alzheimer's disease that are targeted at Aβ-cleaving enzymes should modulate rather than inhibit Aβ generation. These strategies should focus on the factors that induce the conversion of Aβ monomers into toxic soluble oligomers. Another interesting therapeutic approach is to focus on the mechanisms of the different properties of sAPPα. Indeed, increasing sAPPα levels could shift proliferating cells towards tumorigenesis. In contrast to its neuroprotective effects, sAPPα is also able to activate microglia, leading to neurotoxicity. Understanding the mechanisms that underlie the different properties of sAPPα could therefore lead to the development of therapeutic strategies against Alzheimer's disease, which could be curative as well as preventive.
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Affiliation(s)
- Stéphanie Chasseigneaux
- INSERM UMR 894, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France
| | - Bernadette Allinquant
- INSERM UMR 894, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Médecine, Paris, France
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29
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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] [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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30
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Kaden D, Munter LM, Reif B, Multhaup G. The amyloid precursor protein and its homologues: structural and functional aspects of native and pathogenic oligomerization. Eur J Cell Biol 2011; 91:234-9. [PMID: 21459473 DOI: 10.1016/j.ejcb.2011.01.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Revised: 01/24/2011] [Accepted: 01/24/2011] [Indexed: 12/20/2022] Open
Abstract
Over the last 25 years, remarkable progress has been made not only in identifying key molecules of Alzheimer's disease but also in understanding their meaning in the pathogenic state. One hallmark of Alzheimer pathology is the amyloid plaque. A major component of the extracellular deposit is the amyloid-β (Aβ) peptide which is generated from its larger precursor molecule, i.e., the amyloid precursor protein (APP) by consecutive cleavages. Processing is exerted by two enzymes, i.e., the β-secretase and the γ-secretase. We and others have found that the self-association of the amyloid peptide and the dimerization and oligomerization of these proteins is a key factor under native and pathogenic conditions. In particular, the Aβ homodimer represents a nidus for plaque formation and a well defined therapeutic target. Further, dimerization of the APP was reported to increase generation of toxic Aβ whereas heterodimerization with its homologues amyloid precursor like proteins (APLP1 and APLP2) decreased Aβ formation. This review mainly focuses on structural features of the homophilic and heterophilic interactions among APP family proteins. The proposed contact sites are described and the consequences of protein dimerization on their functions and in the pathogenesis of Alzheimer's disease are discussed.
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Affiliation(s)
- Daniela Kaden
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
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31
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S-Nitrosylation of secreted recombinant human glypican-1. Glycoconj J 2010; 26:1247-57. [PMID: 19479373 DOI: 10.1007/s10719-009-9243-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 04/29/2009] [Accepted: 05/11/2009] [Indexed: 10/20/2022]
Abstract
Glypican-1 is a glycosylphosphatidylinositol anchored cell surface S-nitrosylated heparan sulfate proteoglycan that is processed by nitric oxide dependent degradation of its side chains. Cell surface-bound glypican-1 becomes internalized and recycles via endosomes, where the heparan sulphate chains undergo nitric oxide and copper dependent autocleavage at N-unsubstituted glucosamines, back to the Golgi. It is not known if the S-nitrosylation occurs during biosynthesis or recycling of the protein. Here we have generated a recombinant human glypican-1 lacking the glycosylphosphatidylinositol-anchor. We find that this protein is directly secreted into the culture medium both as core protein and proteoglycan form and is not subjected to internalization and further modifications during recycling. By using SDS-PAGE, Western blotting and radiolabeling experiments we show that the glypican-1 can be S-nitrosylated. We have measured the level of S-nitrosylation in the glypican-1 core protein by biotin switch assay and find that the core protein can be S-nitrosylated in the presence of copper II ions and NO donor. Furthermore the glypican-1 proteoglycan produced in the presence of polyamine synthesis inhibitor, alpha-difluoromethylornithine, was endogenously S-nitrosylated and release of nitric oxide induced deaminative autocleavage of the HS side chains of glypican-1. We also show that the N-unsubstituted glucosamine residues are formed during biosynthesis of glypican-1 and that the content increased upon inhibition of polyamine synthesis. It cannot be excluded that endogenous glypican-1 can become further S-nitrosylated during recycling.
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Svensson G, Linse S, Mani K. Chemical and Thermal Unfolding of Glypican-1: Protective Effect of Heparan Sulfate against Heat-Induced Irreversible Aggregation. Biochemistry 2009; 48:9994-10004. [DOI: 10.1021/bi901402x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Gabriel Svensson
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, Biomedical Center A13, SE-221 84 Lund, Sweden
| | - Sara Linse
- Department of Biochemistry, Lund University, Chemical Center, P.O. Box 124, SE-22100 Lund, Sweden
| | - Katrin Mani
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, Biomedical Center A13, SE-221 84 Lund, Sweden
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Soragni A, Zambelli B, Mukrasch MD, Biernat J, Jeganathan S, Griesinger C, Ciurli S, Mandelkow E, Zweckstetter M. Structural Characterization of Binding of Cu(II) to Tau Protein. Biochemistry 2008; 47:10841-51. [DOI: 10.1021/bi8008856] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Alice Soragni
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany, Laboratory of Bioinorganic Chemistry, Department of Agro-Environmental Science and Technology, University of Bologna, Viale Giuseppe Fanin 40, 40127 Bologna, Italy, Max Planck Unit for Structural Molecular Biology, c/o DESY, Hamburg, Germany, CERM, Center for Magnetic Resonance, Firenze, Italy, and DFG Research Center for the Molecular Physiology of the Brain, Göttingen,
| | - Barbara Zambelli
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany, Laboratory of Bioinorganic Chemistry, Department of Agro-Environmental Science and Technology, University of Bologna, Viale Giuseppe Fanin 40, 40127 Bologna, Italy, Max Planck Unit for Structural Molecular Biology, c/o DESY, Hamburg, Germany, CERM, Center for Magnetic Resonance, Firenze, Italy, and DFG Research Center for the Molecular Physiology of the Brain, Göttingen,
| | - Marco D. Mukrasch
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany, Laboratory of Bioinorganic Chemistry, Department of Agro-Environmental Science and Technology, University of Bologna, Viale Giuseppe Fanin 40, 40127 Bologna, Italy, Max Planck Unit for Structural Molecular Biology, c/o DESY, Hamburg, Germany, CERM, Center for Magnetic Resonance, Firenze, Italy, and DFG Research Center for the Molecular Physiology of the Brain, Göttingen,
| | - Jacek Biernat
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany, Laboratory of Bioinorganic Chemistry, Department of Agro-Environmental Science and Technology, University of Bologna, Viale Giuseppe Fanin 40, 40127 Bologna, Italy, Max Planck Unit for Structural Molecular Biology, c/o DESY, Hamburg, Germany, CERM, Center for Magnetic Resonance, Firenze, Italy, and DFG Research Center for the Molecular Physiology of the Brain, Göttingen,
| | - Sadasivam Jeganathan
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany, Laboratory of Bioinorganic Chemistry, Department of Agro-Environmental Science and Technology, University of Bologna, Viale Giuseppe Fanin 40, 40127 Bologna, Italy, Max Planck Unit for Structural Molecular Biology, c/o DESY, Hamburg, Germany, CERM, Center for Magnetic Resonance, Firenze, Italy, and DFG Research Center for the Molecular Physiology of the Brain, Göttingen,
| | - Christian Griesinger
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany, Laboratory of Bioinorganic Chemistry, Department of Agro-Environmental Science and Technology, University of Bologna, Viale Giuseppe Fanin 40, 40127 Bologna, Italy, Max Planck Unit for Structural Molecular Biology, c/o DESY, Hamburg, Germany, CERM, Center for Magnetic Resonance, Firenze, Italy, and DFG Research Center for the Molecular Physiology of the Brain, Göttingen,
| | - Stefano Ciurli
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany, Laboratory of Bioinorganic Chemistry, Department of Agro-Environmental Science and Technology, University of Bologna, Viale Giuseppe Fanin 40, 40127 Bologna, Italy, Max Planck Unit for Structural Molecular Biology, c/o DESY, Hamburg, Germany, CERM, Center for Magnetic Resonance, Firenze, Italy, and DFG Research Center for the Molecular Physiology of the Brain, Göttingen,
| | - Eckhard Mandelkow
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany, Laboratory of Bioinorganic Chemistry, Department of Agro-Environmental Science and Technology, University of Bologna, Viale Giuseppe Fanin 40, 40127 Bologna, Italy, Max Planck Unit for Structural Molecular Biology, c/o DESY, Hamburg, Germany, CERM, Center for Magnetic Resonance, Firenze, Italy, and DFG Research Center for the Molecular Physiology of the Brain, Göttingen,
| | - Markus Zweckstetter
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany, Laboratory of Bioinorganic Chemistry, Department of Agro-Environmental Science and Technology, University of Bologna, Viale Giuseppe Fanin 40, 40127 Bologna, Italy, Max Planck Unit for Structural Molecular Biology, c/o DESY, Hamburg, Germany, CERM, Center for Magnetic Resonance, Firenze, Italy, and DFG Research Center for the Molecular Physiology of the Brain, Göttingen,
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Copper binding to the Alzheimer's disease amyloid precursor protein. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2007; 37:269-79. [PMID: 18030462 PMCID: PMC2921068 DOI: 10.1007/s00249-007-0234-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Revised: 10/24/2007] [Accepted: 10/26/2007] [Indexed: 12/25/2022]
Abstract
Alzheimer’s disease is the fourth biggest killer in developed countries. Amyloid precursor protein (APP) plays a central role in the development of the disease, through the generation of a peptide called Aβ by proteolysis of the precursor protein. APP can function as a metalloprotein and modulate copper transport via its extracellular copper binding domain (CuBD). Copper binding to this domain has been shown to reduce Aβ levels and hence a molecular understanding of the interaction between metal and protein could lead to the development of novel therapeutics to treat the disease. We have recently determined the three-dimensional structures of apo and copper bound forms of CuBD. The structures provide a mechanism by which CuBD could readily transfer copper ions to other proteins. Importantly, the lack of significant conformational changes to CuBD on copper binding suggests a model in which copper binding affects the dimerisation state of APP leading to reduction in Aβ production. We thus predict that disruption of APP dimers may be a novel therapeutic approach to treat Alzheimer’s disease.
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Kong GKW, Adams JJ, Cappai R, Parker MW. Structure of Alzheimer's disease amyloid precursor protein copper-binding domain at atomic resolution. Acta Crystallogr Sect F Struct Biol Cryst Commun 2007; 63:819-24. [PMID: 17909280 PMCID: PMC2339725 DOI: 10.1107/s1744309107041139] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Accepted: 08/20/2007] [Indexed: 01/31/2023]
Abstract
Amyloid precursor protein (APP) plays a central role in the pathogenesis of Alzheimer's disease, as its cleavage generates the Abeta peptide that is toxic to cells. APP is able to bind Cu2+ and reduce it to Cu+ through its copper-binding domain (CuBD). The interaction between Cu2+ and APP leads to a decrease in Abeta production and to alleviation of the symptoms of the disease in mouse models. Structural studies of CuBD have been undertaken in order to better understand the mechanism behind the process. Here, the crystal structure of CuBD in the metal-free form determined to ultrahigh resolution (0.85 A) is reported. The structure shows that the copper-binding residues of CuBD are rather rigid but that Met170, which is thought to be the electron source for Cu2+ reduction, adopts two different side-chain conformations. These observations shed light on the copper-binding and redox mechanisms of CuBD. The structure of CuBD at atomic resolution provides an accurate framework for structure-based design of molecules that will deplete Abeta production.
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Affiliation(s)
- Geoffrey Kwai-Wai Kong
- Biota Structural Biology Laboratory, St Vincent’s Institute, 9 Princes Street, Fitzroy, Victoria 3065, Australia
| | - Julian J. Adams
- Biota Structural Biology Laboratory, St Vincent’s Institute, 9 Princes Street, Fitzroy, Victoria 3065, Australia
| | - Roberto Cappai
- Department of Pathology and Centre for Neuroscience, The University of Melbourne, Victoria 3010, Australia
- The Mental Health Research Institute of Victoria, Parkville, Victoria 3052, Australia
- Bio21 Institute, The University of Melbourne, Victoria 3010, Australia
| | - Michael W. Parker
- Biota Structural Biology Laboratory, St Vincent’s Institute, 9 Princes Street, Fitzroy, Victoria 3065, Australia
- Bio21 Institute, The University of Melbourne, Victoria 3010, Australia
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Mani K, Cheng F, Fransson LA. Heparan Sulfate Degradation Products Can Associate with Oxidized Proteins and Proteasomes. J Biol Chem 2007; 282:21934-44. [PMID: 17540770 DOI: 10.1074/jbc.m701200200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The S-nitrosylated proteoglycan glypican-1 recycles via endosomes where its heparan sulfate chains are degraded into anhydromannose-containing saccharides by NO-catalyzed deaminative cleavage. Because heparan sulfate chains can be associated with intracellular protein aggregates, glypican-1 autoprocessing may be involved in the clearance of misfolded recycling proteins. Here we have arrested and then reactivated NO-catalyzed cleavage in the absence or presence of proteasome inhibitors and analyzed the products present in endosomes or co-precipitating with proteasomes using metabolic radiolabeling and immunomagnet isolation as well as by confocal immunofluorescence microscopy. Upon reactivation of deaminative cleavage in T24 carcinoma cells, [(35)S]sulfate-labeled degradation products appeared in Rab7-positive vesicles and co-precipitated with a 20 S proteasome subunit. Simultaneous inhibition of proteasome activity resulted in a sustained accumulation of degradation products. We also demonstrated that the anhydromannose-containing heparan sulfate degradation products are detected by a hydrazide-based method that also identifies oxidized, i.e. carbonylated, proteins that are normally degraded in proteasomes. Upon inhibition of proteasome activity, pronounced colocalization between carbonyl-staining, anhydro-mannose-containing degradation products, and proteasomes was observed in both T24 carcinoma and N2a neuroblastoma cells. The deaminatively generated products that co-precipitated with the proteasomal subunit contained heparan sulfate but were larger than heparan sulfate oligosaccharides and resistant to both acid and alkali. However, proteolytic degradation released heparan sulfate oligosaccharides. In Niemann-Pick C-1 fibroblasts, where deaminative degradation of heparan sulfate is defective, carbonylated proteins were abundant. Moreover, when glypican-1 expression was silenced in normal fibroblasts, the level of carbonylated proteins increased raising the possibility that deaminative heparan sulfate degradation is involved in the clearance of misfolded proteins.
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Affiliation(s)
- Katrin Mani
- Department of Experimental Medical Science, Section of Neuroscience, Lund University, Biomedical Centre A13, Lund, Sweden.
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Fransson LA, Mani K. Novel aspects of vitamin C: how important is glypican-1 recycling? Trends Mol Med 2007; 13:143-9. [PMID: 17344097 DOI: 10.1016/j.molmed.2007.02.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Revised: 02/06/2007] [Accepted: 02/22/2007] [Indexed: 02/04/2023]
Abstract
The reduced form of vitamin C, ascorbic acid, is well known for its function as an antioxidant and as a protective agent against scurvy. However, many recent studies indicate other functions for vitamin C in mammalian cells. Novel findings provide possible explanations for observed beneficial effects of a high intake of vitamin C on cell growth, gene transcription, host resistance to infection, uptake of polyamines and clearance of misfolded proteins. Vitamin C exerts its effects indirectly via hypoxia-inducible factor, nitric oxide synthase and the heparan sulfate proteoglycan glypican-1, which is deglycanated in a vitamin C- and copper-dependent reaction.
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Affiliation(s)
- Lars-Ake Fransson
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Biomedical Centre A13, Lund University, Lund, Sweden. lars-ake@
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Gralle M, Ferreira ST. Structure and functions of the human amyloid precursor protein: the whole is more than the sum of its parts. Prog Neurobiol 2007; 82:11-32. [PMID: 17428603 DOI: 10.1016/j.pneurobio.2007.02.001] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2006] [Revised: 10/26/2006] [Accepted: 02/01/2007] [Indexed: 12/30/2022]
Abstract
The amyloid precursor protein (APP) is a transmembrane protein that plays major roles in the regulation of several important cellular functions, especially in the nervous system, where it is involved in synaptogenesis and synaptic plasticity. The secreted extracellular domain of APP, sAPPalpha, acts as a growth factor for many types of cells and promotes neuritogenesis in post-mitotic neurons. Alternative proteolytic processing of APP releases potentially neurotoxic species, including the amyloid-beta (Abeta) peptide that is centrally implicated in the pathogenesis of Alzheimer's disease (AD). Reinforcing this biochemical link to neuronal dysfunction and neurodegeneration, APP is also genetically linked to AD. In this review, we discuss the biological functions of APP in the context of tissue morphogenesis and restructuring, where APP appears to play significant roles both as a contact receptor and as a diffusible factor. Structural investigation of APP, which is necessary for a deeper understanding of its roles at a molecular level, has also been advancing rapidly. We summarize recent progress in the determination of the structure of isolated APP fragments and of the conformations of full-length sAPPalpha, in both monomeric and dimeric states. The potential role of APP dimerization for the regulation of its biological functions is also discussed.
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Affiliation(s)
- Matthias Gralle
- Instituto de Bioquímica Médica, Programa de Bioquímica e Biofísica Celular, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21944-590, Brazil.
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Mani K, Cheng F, Fransson LA. Defective nitric oxide-dependent, deaminative cleavage of glypican-1 heparan sulfate in Niemann-Pick C1 fibroblasts. Glycobiology 2006; 16:711-8. [PMID: 16645004 DOI: 10.1093/glycob/cwj121] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Exit of recycling cholesterol from late endosomes is defective in Niemann-Pick C1 (NPC1) and Niemann-Pick C2 (NPC2) diseases. The traffic route of the recycling proteoglycan glypican-1 (Gpc-1) may also involve late endosomes and could thus be affected in these diseases. During recycling through intracellular compartments, the heparan sulfate (HS) side chains of Gpc-1 are deaminatively degraded by nitric oxide (NO) derived from preformed S-nitroso groups in the core protein. We have now investigated whether this NO-dependent Gpc-1 autoprocessing is active in fibroblasts from NPC1 disease. The results showed that Gpc-1 autoprocessing was defective in these cells and, furthermore, greatly depressed in normal fibroblasts treated with U18666A (3-beta-[2-(diethylamino)ethoxy]androst-5-en-17-one), a compound widely used to induce cholesterol accumulation. In both cases, autoprocessing was partially restored by treatment with ascorbate which induced NO release, resulting in deaminative cleavage of HS. However, when NO-dependent Gpc-1 autoprocessing is depressed and heparanase-catalyzed degradation of HS remains active, a truncated Gpc-1 with shorter HS chains would prevail, resulting in fewer NO-sensitive sites/proteoglycan. Therefore, addition of ascorbate to cells with depressed autoprocessing resulted in nitration of tyrosines. Nitration was diminished when heparanase was inhibited with suramin or when Gpc-1 expression was silenced by RNAi. Gpc-1 misprocessing in NPC1 cells could thus contribute to neurodegeneration mediated by reactive nitrogen species.
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Affiliation(s)
- Katrin Mani
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, Biomedical Center C13, SE-221 84 Lund, Sweden
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Xu F, Davis J, Miao J, Previti ML, Romanov G, Ziegler K, Van Nostrand WE. Protease nexin-2/amyloid beta-protein precursor limits cerebral thrombosis. Proc Natl Acad Sci U S A 2005; 102:18135-40. [PMID: 16330760 PMCID: PMC1312400 DOI: 10.1073/pnas.0507798102] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The amyloid beta-protein precursor (AbetaPP) is best known as the parent molecule to the amyloid beta-peptide that accumulates in the brains of patients with Alzheimer's disease. Secreted isoforms of AbetaPP that contain the Kunitz proteinase inhibitor domain are analogous to the previously identified cell-secreted proteinase inhibitor known as protease nexin-2 (PN2). Although PN2/AbetaPP is enriched in brain and in circulating blood platelets, little is understood of its physiological function and potential role in disease processes outside of amyloid beta-peptide generation. We hypothesized that the potent inhibition of certain procoagulant proteinases by PN2/AbetaPP, coupled with its abundance in platelets and brain, indicate that it may function to regulate cerebral thrombosis. Here we show that specific and modest 2-fold overexpression of PN2/AbetaPP in circulating platelets of transgenic mice caused a marked inhibition of thrombosis in vivo. In contrast, deletion of PN2/AbetaPP in AbetaPP gene knockout mice resulted in a significant increase in thrombosis. Similarly, platelet PN2/AbetaPP transgenic mice developed larger hematomas in experimental intracerebral hemorrhage, whereas AbetaPP gene knockout mice exhibited reduced hemorrhage size. These findings indicate that PN2/AbetaPP plays a significant role in regulating cerebral thrombosis and that modest increases in this protein can profoundly enhance cerebral hemorrhage.
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Affiliation(s)
- Feng Xu
- Department of Medicine, Stony Brook University, NY 11794, USA
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