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Vervuurt M, Schrader JM, de Kort AM, Kersten I, Wessels HJCT, Klijn CJM, Schreuder FHBM, Kuiperij HB, Gloerich J, Van Nostrand WE, Verbeek MM. Cerebrospinal fluid shotgun proteomics identifies distinct proteomic patterns in cerebral amyloid angiopathy rodent models and human patients. Acta Neuropathol Commun 2024; 12:6. [PMID: 38191511 PMCID: PMC10775534 DOI: 10.1186/s40478-023-01698-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 11/28/2023] [Indexed: 01/10/2024] Open
Abstract
Cerebral amyloid angiopathy (CAA) is a form of small vessel disease characterised by the progressive deposition of amyloid β protein in the cerebral vasculature, inducing symptoms including cognitive impairment and cerebral haemorrhages. Due to their accessibility and homogeneous disease phenotypes, animal models are advantageous platforms to study diseases like CAA. Untargeted proteomics studies of CAA rat models (e.g. rTg-DI) and CAA patients provide opportunities for the identification of novel biomarkers of CAA. We performed untargeted, data-independent acquisition proteomic shotgun analyses on the cerebrospinal fluid of rTg-DI rats and wild-type (WT) littermates. Rodents were analysed at 3 months (n = 6/10), 6 months (n = 8/8), and 12 months (n = 10/10) for rTg-DI and WT respectively. For humans, proteomic analyses were performed on CSF of sporadic CAA patients (sCAA) and control participants (n = 39/28). We show recurring patterns of differentially expressed (mostly increased) proteins in the rTg-DI rats compared to wild type rats, especially of proteases of the cathepsin protein family (CTSB, CTSD, CTSS), and their main inhibitor (CST3). In sCAA patients, decreased levels of synaptic proteins (e.g. including VGF, NPTX1, NRXN2) and several members of the granin family (SCG1, SCG2, SCG3, SCG5) compared to controls were discovered. Additionally, several serine protease inhibitors of the SERPIN protein family (including SERPINA3, SERPINC1 and SERPING1) were differentially expressed compared to controls. Fifteen proteins were significantly altered in both rTg-DI rats and sCAA patients, including (amongst others) SCG5 and SERPING1. These results identify specific groups of proteins likely involved in, or affected by, pathophysiological processes involved in CAA pathology such as protease and synapse function of rTg-DI rat models and sCAA patients, and may serve as candidate biomarkers for sCAA.
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Affiliation(s)
- Marc Vervuurt
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, 830 TML, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Joseph M Schrader
- Department of Biomedical and Pharmaceutical Sciences, George & Anne Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
| | - Anna M de Kort
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, 830 TML, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Iris Kersten
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, 830 TML, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Hans J C T Wessels
- Department of Human Genetics, Translational Metabolic Laboratory, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Catharina J M Klijn
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, 830 TML, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Floris H B M Schreuder
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, 830 TML, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - H Bea Kuiperij
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, 830 TML, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Jolein Gloerich
- Department of Human Genetics, Translational Metabolic Laboratory, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - William E Van Nostrand
- Department of Biomedical and Pharmaceutical Sciences, George & Anne Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
| | - Marcel M Verbeek
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, 830 TML, Radboud University Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
- Department of Human Genetics, Translational Metabolic Laboratory, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
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2
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Onodera W, Asahi T, Sawamura N. Rapid evolution of mammalian APLP1 as a synaptic adhesion molecule. Sci Rep 2021; 11:11305. [PMID: 34050225 PMCID: PMC8163877 DOI: 10.1038/s41598-021-90737-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/17/2021] [Indexed: 01/10/2023] Open
Abstract
Amyloid precursor protein (APP) family members are involved in essential neuronal development including neurite outgrowth, neuronal migration and maturation of synapse and neuromuscular junction. Among the APP gene family members, amyloid precursor-like protein 1 (APLP1) is selectively expressed in neurons and has specialized functions during synaptogenesis. Although a potential role for APLP1 in neuronal evolution has been indicated, its precise evolutionary and functional contributions are unknown. This study shows the molecular evolution of the vertebrate APP family based on phylogenetic analysis, while contrasting the evolutionary differences within the APP family. Phylogenetic analysis showed 15 times higher substitution rate that is driven by positive selection at the stem branch of the mammalian APLP1, resulting in dissimilar protein sequences compared to APP/APLP2. Docking simulation identified one positively selected site in APLP1 that alters the heparin-binding site, which could affect its function, and dimerization rate. Furthermore, the evolutionary rate covariation between the mammalian APP family and synaptic adhesion molecules (SAMs) was confirmed, indicating that only APLP1 has evolved to gain synaptic adhesion property. Overall, our results suggest that the enhanced synaptogenesis property of APLP1 as one of the SAMs may have played a role in mammalian brain evolution.
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Affiliation(s)
- Wataru Onodera
- Faculty of Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsu, Shinjuku, Tokyo, 162-8480, Japan
| | - Toru Asahi
- Faculty of Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsu, Shinjuku, Tokyo, 162-8480, Japan.,Research Organization for Nano & Life Innovation, Waseda University, #03C309, TWIns, 2-2 Wakamatsu, Shinjuku, Tokyo, 162-8480, Japan
| | - Naoya Sawamura
- Research Organization for Nano & Life Innovation, Waseda University, #03C309, TWIns, 2-2 Wakamatsu, Shinjuku, Tokyo, 162-8480, Japan. .,Green Computing Systems Research Organization, Waseda University, Shinjuku, Japan.
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3
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Kanyo R, Leighton PLA, Neil GJ, Locskai LF, Allison WT. Amyloid-β precursor protein mutant zebrafish exhibit seizure susceptibility that depends on prion protein. Exp Neurol 2020; 328:113283. [PMID: 32165257 DOI: 10.1016/j.expneurol.2020.113283] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 02/03/2020] [Accepted: 03/08/2020] [Indexed: 12/11/2022]
Abstract
It has been proposed that Amyloid β Precursor Protein (APP) might act as a rheostat controlling neuronal excitability, but mechanisms have remained untested. APP and its catabolite Aβ are known to impact upon synapse function and dysfunction via their interaction with the prion protein (PrPC), suggesting a candidate pathway. Here we test if PrPC is required for this APP function in vivo, perhaps via modulating mGluR5 ion channels. We engineered zebrafish to lack homologs of PrPC and APP, allowing us to assess their purported genetic and physiological interactions in CNS development. We generated four appa null alleles as well as prp1-/-;appa-/- double mutants (engineering of prp1 mutant alleles is described elsewhere). Unexpectedly, appa-/- and compound prp1-/-;appa-/- mutants are viable and lacked overt phenotypes (except being slightly smaller than wildtype fish at some developmental stages). Zebrafish prp1-/- mutants were substantially more sensitive to appa knockdown than wildtype fish, and both zebrafish prp1 and mammalian Prnp mRNA were significantly able to partially rescue this effect. Further, appa-/- mutants exhibited increased seizures upon exposure to low doses of convulsant. The mechanism of this seizure susceptibility requires prp1 insomuch that seizures were significantly dampened to wildtype levels in prp1-/-;appa-/- mutants. Inhibiting mGluR5 channels, which may be downstream of PrPC, increased seizure intensity only in prp1-/- mutants, and this seizure mechanism required intact appa. Taken together, these results support an intriguing genetic interaction between prp1 and appa with their shared roles impacting upon neuron hyperexcitability, thus complementing and extending past works detailing their biochemical interaction(s).
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Affiliation(s)
- Richard Kanyo
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Patricia L A Leighton
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Gavin J Neil
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Laszlo F Locskai
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - W Ted Allison
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada; Department of Medical Genetics, University of Alberta, Edmonton, AB T6G 2H7, Canada.
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4
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Ray B, Maloney B, Sambamurti K, Karnati HK, Nelson PT, Greig NH, Lahiri DK. Rivastigmine modifies the α-secretase pathway and potentially early Alzheimer's disease. Transl Psychiatry 2020; 10:47. [PMID: 32066688 PMCID: PMC7026402 DOI: 10.1038/s41398-020-0709-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 11/25/2019] [Accepted: 12/19/2019] [Indexed: 12/12/2022] Open
Abstract
Rivastigmine (or Exelon) is a cholinesterase inhibitor, currently used as a symptomatic treatment for mild-to-moderate Alzheimer's disease (AD). Amyloid-β peptide (Aβ) generated from its precursor protein (APP) by β-secretase (or BACE1) and γ-secretase endoproteolysis. Alternative APP cleavage by α-secretase (a family of membrane-bound metalloproteases- Adamalysins) precludes the generation of toxic Aβ and yields a neuroprotective and neurotrophic secreted sAPPα fragment. Several signal transduction pathways, including protein kinase C and MAP kinase, stimulate α-secretase. We present data to suggest that rivastigmine, in addition to anticholinesterase activity, directs APP processing away from BACE1 and towards α-secretases. We treated rat neuronal PC12 cells and primary human brain (PHB) cultures with rivastigmine and the α-secretase inhibitor TAPI and assayed for levels of APP processing products and α-secretases. We subsequently treated 3×Tg (transgenic) mice with rivastigmine and harvested hippocampi to assay for levels of APP processing products. We also assayed postmortem human control, AD, and AD brains from subjects treated with rivastigmine for levels of APP metabolites. Rivastigmine dose-dependently promoted α-secretase activity by upregulating levels of ADAM-9, -10, and -17 α-secretases in PHB cultures. Co-treatment with TAPI eliminated rivastigmine-induced sAPPα elevation. Rivastigmine treatment elevated levels of sAPPα in 3×Tg mice. Consistent with these results, we also found elevated sAPPα in postmortem brain samples from AD patients treated with rivastigmine. Rivastigmine can modify the levels of several shedding proteins and directs APP processing toward the non-amyloidogenic pathway. This novel property of rivastigmine can be therapeutically exploited for disease-modifying intervention that goes beyond symptomatic treatment for AD.
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Affiliation(s)
- Balmiki Ray
- grid.257413.60000 0001 2287 3919Department of Psychiatry, Laboratory of Molecular Neurogenetics, Indiana University School of Medicine, Indianapolis, IN 46202 USA
| | - Bryan Maloney
- grid.257413.60000 0001 2287 3919Department of Psychiatry, Laboratory of Molecular Neurogenetics, Indiana University School of Medicine, Indianapolis, IN 46202 USA ,grid.257413.60000 0001 2287 3919Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN 46202 USA
| | - Kumar Sambamurti
- grid.259828.c0000 0001 2189 3475Department of Neurosciences, Medical University of South Carolina, Charleston, 29425 SC USA
| | - Hanuma K. Karnati
- grid.419475.a0000 0000 9372 4913National Institute on Aging, Drug Design and Development Section, Bethesda, MD 20892 USA
| | - Peter T. Nelson
- grid.266539.d0000 0004 1936 8438Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536 USA
| | - Nigel H. Greig
- grid.419475.a0000 0000 9372 4913National Institute on Aging, Drug Design and Development Section, Bethesda, MD 20892 USA
| | - Debomoy K. Lahiri
- grid.257413.60000 0001 2287 3919Department of Psychiatry, Laboratory of Molecular Neurogenetics, Indiana University School of Medicine, Indianapolis, IN 46202 USA ,grid.257413.60000 0001 2287 3919Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN 46202 USA ,grid.257413.60000 0001 2287 3919Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202 USA
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5
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Kepp KP, Squitti R. Copper imbalance in Alzheimer’s disease: Convergence of the chemistry and the clinic. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2019.06.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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Bocharov EV, Nadezhdin KD, Urban AS, Volynsky PE, Pavlov KV, Efremov RG, Arseniev AS, Bocharova OV. Familial L723P Mutation Can Shift the Distribution between the Alternative APP Transmembrane Domain Cleavage Cascades by Local Unfolding of the Ε-Cleavage Site Suggesting a Straightforward Mechanism of Alzheimer's Disease Pathogenesis. ACS Chem Biol 2019; 14:1573-1582. [PMID: 31180641 DOI: 10.1021/acschembio.9b00309] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Alzheimer's disease is an age-related pathology associated with accumulation of amyloid-β peptides, products of enzymatic cleavage of amyloid-β precursor protein (APP) by secretases. Several familial mutations causing early onset of the disease have been identified in the APP transmembrane (TM) domain. The mutations influence production of amyloid-β, but the molecular mechanisms of this effect are unclear. The "Australian" (L723P) mutation located in the C-termini of APP TM domain is associated with autosomal-dominant, early onset Alzheimer's disease. Herein, we describe the impact of familial L723P mutation on the structural-dynamic behavior of APP TM domain studied by high-resolution NMR in membrane-mimicking micelles and augmented by molecular dynamics simulations in explicit lipid bilayer. We found L723P mutation to cause local unfolding of the C-terminal turn of the APP TM domain helix and increase its accessibility to water required for cleavage of the protein backbone by γ-secretase in the ε-site, thus switching between alternative ("pathogenic" and "non-pathogenic") cleavage cascades. These findings suggest a straightforward mechanism of the pathogenesis associated with this mutation, and are of generic import for understanding the molecular-level events associated with APP sequential proteolysis resulting in accumulation of the pathogenic forms of amyloid-β. Moreover, age-related onset of Alzheimer's disease can be explained by a similar mechanism, where the effect of mutation is emulated by the impact of local environmental factors, such as oxidative stress and/or membrane lipid composition. Knowledge of the mechanisms regulating generation of amyloidogenic peptides of different lengths is essential for development of novel treatment strategies of the Alzheimer's disease.
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Affiliation(s)
- Eduard V. Bocharov
- Shemyakin−Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, 117198, Russian Federation
- Moscow Institute of Physics and Technology, Dolgoprudnyi, 141701, Russian Federation
| | - Kirill D. Nadezhdin
- Shemyakin−Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, 117198, Russian Federation
- Moscow Institute of Physics and Technology, Dolgoprudnyi, 141701, Russian Federation
| | - Anatoly S. Urban
- Shemyakin−Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, 117198, Russian Federation
- Moscow Institute of Physics and Technology, Dolgoprudnyi, 141701, Russian Federation
| | - Pavel E. Volynsky
- Shemyakin−Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, 117198, Russian Federation
| | - Konstantin V. Pavlov
- Federal Clinical Center of Physical-Chemical Medicine of FMBA, Moscow, 119435, Russian Federation
| | - Roman G. Efremov
- Shemyakin−Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, 117198, Russian Federation
- Moscow Institute of Physics and Technology, Dolgoprudnyi, 141701, Russian Federation
- National Research University Higher School of Economics, Moscow, 101000, Russian Federation
| | - Alexander S. Arseniev
- Shemyakin−Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, 117198, Russian Federation
- Moscow Institute of Physics and Technology, Dolgoprudnyi, 141701, Russian Federation
| | - Olga V. Bocharova
- Shemyakin−Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, 117198, Russian Federation
- Moscow Institute of Physics and Technology, Dolgoprudnyi, 141701, Russian Federation
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7
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Matrone C, Iannuzzi F, Annunziato L. The Y 682ENPTY 687 motif of APP: Progress and insights toward a targeted therapy for Alzheimer's disease patients. Ageing Res Rev 2019; 52:120-128. [PMID: 31039414 DOI: 10.1016/j.arr.2019.04.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 03/04/2019] [Accepted: 04/10/2019] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disorder for which no curative treatments, disease modifying strategies or effective symptomatic therapies exist. Current pharmacologic treatments for AD can only decelerate the progression of the disease for a short time, often at the cost of severe side effects. Therefore, there is an urgent need for biomarkers able to diagnose AD at its earliest stages, to conclusively track disease progression, and to accelerate the clinical development of innovative therapies. Scientific research and economic efforts for the development of pharmacotherapies have recently homed in on the hypothesis that neurotoxic β-amyloid (Aβ) peptides in their oligomeric or fibrillary forms are primarily responsible for the cognitive impairment and neuronal death seen in AD. As such, modern pharmacologic approaches are largely based on reducing production by inhibiting β and γ secretase cleavage of the amyloid precursor protein (APP) or on dissolving existing cerebral Aβ plaques or to favor Aβ clearance from the brain. The following short review aims to persuade the reader of the idea that APP plays a much larger role in AD pathogenesis. APP plays a greater role in AD pathogenesis than its role as the precursor for Aβ peptides: both the abnormal cleavage of APP leading to Aβ peptide accumulation and the disruption of APP physiological functions contribute to AD pathogenesis. We summarize our recent results on the role played by the C-terminal APP motif -the Y682ENPTY68 motif- in APP function and dysfunction, and we provide insights into targeting the Tyr682 residue of APP as putative novel strategy in AD.
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8
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Roisman LC, Han S, Chuei MJ, Connor AR, Cappai R. The crystal structure of amyloid precursor-like protein 2 E2 domain completes the amyloid precursor protein family. FASEB J 2019; 33:5076-5081. [PMID: 30608876 DOI: 10.1096/fj.201802315r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The amyloid precursor-like protein 2 (APLP2) molecule is a type I transmembrane protein that is crucial for survival, cell-cell adhesion, neuronal development, myelination, cancer metastasis, modulation of metal, and glucose and insulin homeostasis. Moreover, the importance of the amyloid precursor protein (APP) family in biology and disease is very well known because of its central role in Alzheimer disease. In this study, we determined the crystal structure of the independently folded E2 domain of APLP2 and compared that with its paralogues APP and APLP2, demonstrating high overall structural similarities. The crystal structure of APLP2 E2 was solved as an antiparallel dimer, and analysis of the protein interfaces revealed a distinct mode of dimerization that differs from the previously reported dimerization of either APP or APLP1. Analysis of the APLP2 E2 metal binding sites suggested it binds zinc and copper in a similar manner to APP and APLP1. The structure of this key protein might suggest a relationship between the distinct mode of dimerization and its biologic functions.-Roisman, L. C., Han, S., Chuei, M. J., Connor, A. R., Cappai, R. The crystal structure of amyloid precursor-like protein 2 E2 domain completes the amyloid precursor protein family.
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Affiliation(s)
- Laila C Roisman
- Department of Pathology, The University of Melbourne, Victoria, Australia; and.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Sen Han
- Department of Pathology, The University of Melbourne, Victoria, Australia; and.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Mun Joo Chuei
- Department of Pathology, The University of Melbourne, Victoria, Australia; and.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Andrea R Connor
- Department of Pathology, The University of Melbourne, Victoria, Australia; and.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Roberto Cappai
- Department of Pathology, The University of Melbourne, Victoria, Australia; and.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia.,Department of Pharmacology and Therapeutics, The University of Melbourne, Victoria, Australia
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Recinto SJ, Paschkowsky S, Munter LM. An alternative processing pathway of APP reveals two distinct cleavage modes for rhomboid protease RHBDL4. Biol Chem 2018; 399:1399-1408. [DOI: 10.1515/hsz-2018-0259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 08/28/2018] [Indexed: 02/02/2023]
Abstract
AbstractSince the first genetic description of a rhomboid inDrosophila melanogaster, tremendous efforts have been geared towards elucidating the proteolytic mechanism of this particular class of intramembrane proteases. In particular, mammalian rhomboid proteases sparked our interest and we aimed to investigate the human homologue RHBDL4. In light of our recent finding of the amyloid precursor protein (APP) family as efficient substrates of RHBDL4, we were enticed to further study the specific proteolytic mechanism of this enzyme by comparing cleavage patterns of wild type APP and APP TMS chimeras. Here, we demonstrate that the introduction of positively charged amino acid residues in the TMS redirects the RHBDL4-mediated cleavage of APP from its ectodomain closer towards the TMS, possibly inducing an ER-associated degradation (ERAD) of the substrate. In addition, we concluded that the cytoplasmic tail and proposed palmitoylation sites in the ectodomain of APP are not essential for the RHBDL4-mediated APP processing. In summary, our previously identified APP ectodomain cleavages by RHBDL4 are a subsidiary mechanism to the proposed RHBDL4-mediated ERAD of substrates likely through a single cleavage near or within the TMS.
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Hashimoto M, Ho G, Sugama S, Takamatsu Y, Shimizu Y, Takenouchi T, Waragai M, Masliah E. Evolvability of Amyloidogenic Proteins in Human Brain. J Alzheimers Dis 2018; 62:73-83. [PMID: 29439348 PMCID: PMC5817905 DOI: 10.3233/jad-170894] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2017] [Indexed: 12/29/2022]
Abstract
Currently, the physiological roles of amyloidogenic proteins (APs) in human brain, such as amyloid-β and α-synuclein, are elusive. Given that many APs arose by gene duplication and have been resistant against the pressures of natural selection, APs may be associated with some functions that are advantageous for survival of offspring. Nonetheless, evolvability is the sole physiological quality of APs that has been characterized in microorganisms such as yeast. Since yeast and human brain may share similar strategies in coping with diverse range of critical environmental stresses, the objective of this paper was to discuss the potential role of evolvability of APs in aging-associated neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease. Given the heterogeneity of APs in terms of structure and cytotoxicity, it is argued that APs might be involved in preconditioning against diverse stresses in human brain. It is further speculated that these stress-related APs, most likely protofibrillar forms, might be transmitted to offspring via the germline, conferring preconditioning against forthcoming stresses. Thus, APs might represent a vehicle for the inheritance of the acquired characteristics against environmental stresses. Curiously, such a characteristic of APs is reminiscent of Charles Darwin's 'gemmules', imagined molecules of heritability described in his pangenesis theory. We propose that evolvability might be a physiological function of APs during the reproductive stage and neurodegenerative diseases could be a by-product effect manifested later in aging. Collectively, our evolvability hypothesis may play a complementary role in the pathophysiology of APs with the conventional amyloid cascade hypothesis.
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Affiliation(s)
- Makoto Hashimoto
- Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan
| | - Gilbert Ho
- PCND Neuroscience Research Institute, Poway, CA, USA
| | - Shuei Sugama
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| | - Yoshiki Takamatsu
- Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan
| | - Yuka Shimizu
- Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan
| | - Takato Takenouchi
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
| | - Masaaki Waragai
- Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan
| | - Eliezer Masliah
- Division of Neurosciences, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
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Eggert S, Gonzalez AC, Thomas C, Schilling S, Schwarz SM, Tischer C, Adam V, Strecker P, Schmidt V, Willnow TE, Hermey G, Pietrzik CU, Koo EH, Kins S. Dimerization leads to changes in APP (amyloid precursor protein) trafficking mediated by LRP1 and SorLA. Cell Mol Life Sci 2018; 75:301-322. [PMID: 28799085 PMCID: PMC11105302 DOI: 10.1007/s00018-017-2625-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 07/17/2017] [Accepted: 08/08/2017] [Indexed: 12/22/2022]
Abstract
Proteolytic cleavage of the amyloid precursor protein (APP) by α-, β- and γ-secretases is a determining factor in Alzheimer's disease (AD). Imbalances in the activity of all three enzymes can result in alterations towards pathogenic Aβ production. Proteolysis of APP is strongly linked to its subcellular localization as the secretases involved are distributed in different cellular compartments. APP has been shown to dimerize in cis-orientation, affecting Aβ production. This might be explained by different substrate properties defined by the APP oligomerization state or alternatively by altered APP monomer/dimer localization. We investigated the latter hypothesis using two different APP dimerization systems in HeLa cells. Dimerization caused a decreased localization of APP to the Golgi and at the plasma membrane, whereas the levels in the ER and in endosomes were increased. Furthermore, we observed via live cell imaging and biochemical analyses that APP dimerization affects its interaction with LRP1 and SorLA, suggesting that APP dimerization modulates its interplay with sorting molecules and in turn its localization and processing. Thus, pharmacological approaches targeting APP oligomerization properties might open novel strategies for treatment of AD.
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Affiliation(s)
- Simone Eggert
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany.
| | - A C Gonzalez
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
- Institute for Biochemistry, Christian Albrechts University Kiel, 24118, Kiel, Germany
| | - C Thomas
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
| | - S Schilling
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
| | - S M Schwarz
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
- Institute for Medical Virology, University of Frankfurt, 60596, Frankfurt, Germany
| | | | - V Adam
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
| | - P Strecker
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
| | - V Schmidt
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - T E Willnow
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - G Hermey
- Institute for Molecular and Cellular Cognition, Center for Molecular University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - C U Pietrzik
- Institute for Pathobiochemistry, Molecular Neurodegeneration, University Medical Center of the Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - E H Koo
- Department of Neuroscience, University of California San Diego (UCSD), La Jolla, CA, 92093-0662, USA
| | - Stefan Kins
- Department of Human Biology and Human Genetics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany.
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13
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Lanchec E, Désilets A, Béliveau F, Flamier A, Mahmoud S, Bernier G, Gris D, Leduc R, Lavoie C. The type II transmembrane serine protease matriptase cleaves the amyloid precursor protein and reduces its processing to β-amyloid peptide. J Biol Chem 2017; 292:20669-20682. [PMID: 29054928 DOI: 10.1074/jbc.m117.792911] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 10/16/2017] [Indexed: 11/06/2022] Open
Abstract
Recent studies have reported that many proteases, besides the canonical α-, β-, and γ-secretases, cleave the amyloid precursor protein (APP) and modulate β-amyloid (Aβ) peptide production. Moreover, specific APP isoforms contain Kunitz protease-inhibitory domains, which regulate the proteolytic activity of serine proteases. This prompted us to investigate the role of matriptase, a member of the type II transmembrane serine protease family, in APP processing. Using quantitative RT-PCR, we detected matriptase mRNA in several regions of the human brain with an enrichment in neurons. RNA sequencing data of human dorsolateral prefrontal cortex revealed relatively high levels of matriptase RNA in young individuals, whereas lower levels were detected in older individuals. We further demonstrate that matriptase and APP directly interact with each other and that matriptase cleaves APP at a specific arginine residue (Arg-102) both in vitro and in cells. Site-directed (Arg-to-Ala) mutagenesis of this cleavage site abolished matriptase-mediated APP processing. Moreover, we observed that a soluble, shed matriptase form cleaves endogenous APP in SH-SY5Y cells and that this cleavage significantly reduces APP processing to Aβ40. In summary, this study identifies matriptase as an APP-cleaving enzyme, an activity that could have important consequences for the abundance of Aβ and in Alzheimer's disease pathology.
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Affiliation(s)
- Erwan Lanchec
- From the Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec J1H5N4, Canada
| | - Antoine Désilets
- From the Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec J1H5N4, Canada
| | - François Béliveau
- From the Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec J1H5N4, Canada
| | - Anthony Flamier
- Stem Cell and Developmental Biology Laboratory, Hôpital Maisonneuve-Rosemont, 5415 Boulevard de l'Assomption, Montréal, Quebec H1T 2M4, Canada
| | - Shaimaa Mahmoud
- Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec J1H5N4, Canada, and
| | - Gilbert Bernier
- Stem Cell and Developmental Biology Laboratory, Hôpital Maisonneuve-Rosemont, 5415 Boulevard de l'Assomption, Montréal, Quebec H1T 2M4, Canada.,Department of Neurosciences, Université de Montréal, Montréal, Quebec H3C 3J7, Canada
| | - Denis Gris
- Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec J1H5N4, Canada, and
| | - Richard Leduc
- From the Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec J1H5N4, Canada,
| | - Christine Lavoie
- From the Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec J1H5N4, Canada,
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14
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Cao Z, Hutchison JM, Sanders CR, Bowie JU. Backbone Hydrogen Bond Strengths Can Vary Widely in Transmembrane Helices. J Am Chem Soc 2017; 139:10742-10749. [PMID: 28692798 PMCID: PMC5560243 DOI: 10.1021/jacs.7b04819] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
![]()
Although
backbone hydrogen bonds in transmembrane (TM) helices
have the potential to be very strong due to the low dielectric and
low water environment of the membrane, their strength has never been
assessed experimentally. Moreover, variations in hydrogen bond strength
might be necessary to facilitate the TM helix breaking and bending
that is often needed to satisfy functional imperatives. Here we employed
equilibrium hydrogen/deuterium fractionation factors to measure backbone
hydrogen bond strengths in the TM helix of the amyloid precursor protein
(APP). We find an enormous range of hydrogen bond free energies, with
some weaker than water–water hydrogen bonds and some over 6
kcal/mol stronger than water–water hydrogen bonds. We find
that weak hydrogen bonds are at or near preferred γ-secretase
cleavage sites, suggesting that the sequence of APP and possibly other
cleaved TM helices may be designed, in part, to make their backbones
accessible for cleavage. The finding that hydrogen bond strengths
in a TM helix can vary widely has implications for membrane protein
function, dynamics, evolution, and design.
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Affiliation(s)
- Zheng Cao
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, University of California , Los Angeles, California 90095, United States
| | - James M Hutchison
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Charles R Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - James U Bowie
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, University of California , Los Angeles, California 90095, United States
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15
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Manduca Contactin Regulates Amyloid Precursor Protein-Dependent Neuronal Migration. J Neurosci 2017; 36:8757-75. [PMID: 27535920 DOI: 10.1523/jneurosci.0729-16.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 07/12/2016] [Indexed: 01/06/2023] Open
Abstract
UNLABELLED Amyloid precursor protein (APP) was originally identified as the source of β-amyloid peptides that accumulate in Alzheimer's disease (AD), but it also has been implicated in the control of multiple aspects of neuronal motility. APP belongs to an evolutionarily conserved family of transmembrane proteins that can interact with a variety of adapter and signaling molecules. Recently, we showed that both APP and its insect ortholog [APPL (APP-Like)] directly bind the heterotrimeric G-protein Goα, supporting the model that APP can function as an unconventional Goα-coupled receptor. We also adapted a well characterized assay of neuronal migration in the hawkmoth, Manduca sexta, to show that APPL-Goα signaling restricts ectopic growth within the developing nervous system, analogous to the role postulated for APP family proteins in controlling migration within the mammalian cortex. Using this assay, we have now identified Manduca Contactin (MsContactin) as an endogenous ligand for APPL, consistent with previous work showing that Contactins interact with APP family proteins in other systems. Using antisense-based knockdown protocols and fusion proteins targeting both proteins, we have shown that MsContactin is selectively expressed by glial cells that ensheath the migratory neurons (expressing APPL), and that MsContactin-APPL interactions normally prevent inappropriate migration and outgrowth. These results provide new evidence that Contactins can function as authentic ligands for APP family proteins that regulate APP-dependent responses in the developing nervous system. They also support the model that misregulated Contactin-APP interactions might provoke aberrant activation of Goα and its effectors, thereby contributing to the neurodegenerative sequelae that typify AD. SIGNIFICANCE STATEMENT Members of the amyloid precursor protein (APP) family participate in many aspects of neuronal development, but the ligands that normally activate APP signaling have remained controversial. This research provides new evidence that members of the Contactin family function as authentic ligands for APP and its orthologs, and that this evolutionarily conserved class of membrane-attached proteins regulates key aspects of APP-dependent migration and outgrowth in the embryonic nervous system. By defining the normal role of Contactin-APP signaling during development, these studies also provide the framework for investigating how the misregulation of Contactin-APP interactions might contribute to neuronal dysfunction in the context of both normal aging and neurodegenerative conditions, including Alzheimer's disease.
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16
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Weingarten J, Weingarten M, Wegner M, Volknandt W. APP-A Novel Player within the Presynaptic Active Zone Proteome. Front Mol Neurosci 2017; 10:43. [PMID: 28265241 PMCID: PMC5316543 DOI: 10.3389/fnmol.2017.00043] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 02/07/2017] [Indexed: 11/13/2022] Open
Abstract
The amyloid precursor protein (APP) was discovered in the 1980s as the precursor protein of the amyloid A4 peptide. The amyloid A4 peptide, also known as A-beta (Aβ), is the main constituent of senile plaques implicated in Alzheimer's disease (AD). In association with the amyloid deposits, increasing impairments in learning and memory as well as the degeneration of neurons especially in the hippocampus formation are hallmarks of the pathogenesis of AD. Within the last decades much effort has been expended into understanding the pathogenesis of AD. However, little is known about the physiological role of APP within the central nervous system (CNS). Allocating APP to the proteome of the highly dynamic presynaptic active zone (PAZ) identified APP as a novel player within this neuronal communication and signaling network. The analysis of the hippocampal PAZ proteome derived from APP-mutant mice demonstrates that APP is tightly embedded in the underlying protein network. Strikingly, APP deletion accounts for major dysregulation within the PAZ proteome network. Ca2+-homeostasis, neurotransmitter release and mitochondrial function are affected and resemble the outcome during the pathogenesis of AD. The observed changes in protein abundance that occur in the absence of APP as well as in AD suggest that APP is a structural and functional regulator within the hippocampal PAZ proteome. Within this review article, we intend to introduce APP as an important player within the hippocampal PAZ proteome and to outline the impact of APP deletion on individual PAZ proteome subcommunities.
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Affiliation(s)
- Jens Weingarten
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Goethe University Frankfurt am Main, Germany
| | - Melanie Weingarten
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Goethe University Frankfurt am Main, Germany
| | - Martin Wegner
- Department of Molecular Bioinformatics, Goethe University Frankfurt am Main, Germany
| | - Walter Volknandt
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Goethe University Frankfurt am Main, Germany
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17
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Copenhaver PF, Kögel D. Role of APP Interactions with Heterotrimeric G Proteins: Physiological Functions and Pathological Consequences. Front Mol Neurosci 2017; 10:3. [PMID: 28197070 PMCID: PMC5281615 DOI: 10.3389/fnmol.2017.00003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 01/05/2017] [Indexed: 12/27/2022] Open
Abstract
Following the discovery that the amyloid precursor protein (APP) is the source of β-amyloid peptides (Aβ) that accumulate in Alzheimer’s disease (AD), structural analyses suggested that the holoprotein resembles a transmembrane receptor. Initial studies using reconstituted membranes demonstrated that APP can directly interact with the heterotrimeric G protein Gαo (but not other G proteins) via an evolutionarily G protein-binding motif in its cytoplasmic domain. Subsequent investigations in cell culture showed that antibodies against the extracellular domain of APP could stimulate Gαo activity, presumably mimicking endogenous APP ligands. In addition, chronically activating wild type APP or overexpressing mutant APP isoforms linked with familial AD could provoke Go-dependent neurotoxic responses, while biochemical assays using human brain samples suggested that the endogenous APP-Go interactions are perturbed in AD patients. More recently, several G protein-dependent pathways have been implicated in the physiological roles of APP, coupled with evidence that APP interacts both physically and functionally with Gαo in a variety of contexts. Work in insect models has demonstrated that the APP ortholog APPL directly interacts with Gαo in motile neurons, whereby APPL-Gαo signaling regulates the response of migratory neurons to ligands encountered in the developing nervous system. Concurrent studies using cultured mammalian neurons and organotypic hippocampal slice preparations have shown that APP signaling transduces the neuroprotective effects of soluble sAPPα fragments via modulation of the PI3K/Akt pathway, providing a mechanism for integrating the stress and survival responses regulated by APP. Notably, this effect was also inhibited by pertussis toxin, indicating an essential role for Gαo/i proteins. Unexpectedly, C-terminal fragments (CTFs) derived from APP have also been found to interact with Gαs, whereby CTF-Gαs signaling can promote neurite outgrowth via adenylyl cyclase/PKA-dependent pathways. These reports offer the intriguing perspective that G protein switching might modulate APP-dependent responses in a context-dependent manner. In this review, we provide an up-to-date perspective on the model that APP plays a variety of roles as an atypical G protein-coupled receptor in both the developing and adult nervous system, and we discuss the hypothesis that disruption of these normal functions might contribute to the progressive neuropathologies that typify AD.
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Affiliation(s)
- Philip F Copenhaver
- Department of Cell, Developmental and Cancer Biology, Oregon Health & Sciences University, Portland OR, USA
| | - Donat Kögel
- Experimental Neurosurgery, Goethe University Frankfurt Frankfurt am Main, Germany
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18
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Takamatsu Y, Ho G, Koike W, Sugama S, Takenouchi T, Waragai M, Wei J, Sekiyama K, Hashimoto M. Combined immunotherapy with "anti-insulin resistance" therapy as a novel therapeutic strategy against neurodegenerative diseases. NPJ Parkinsons Dis 2017; 3:4. [PMID: 28649604 PMCID: PMC5445606 DOI: 10.1038/s41531-016-0001-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 08/07/2016] [Accepted: 10/30/2016] [Indexed: 12/22/2022] Open
Abstract
Protein aggregation is a pathological hallmark of and may play a central role in the neurotoxicity in age-associated neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. Accordingly, inhibiting aggregation of amyloidogenic proteins, including amyloid β and α-synuclein, has been a main therapeutic target for these disorders. Among various strategies, amyloid β immunotherapy has been extensively investigated in Alzheimer's disease, followed by similar studies of α-synuclein in Parkinson's disease. Notably, a recent study of solanezumab, an amyloid β monoclonal antibody, raises hope for the further therapeutic potential of immunotherapy, not only in Alzheimer's disease, but also for other neurodegenerative disorders, including Parkinson's disease. Thus, it is expected that further refinement of immunotherapy against neurodegenerative diseases may lead to increasing efficacy. Meanwhile, type II diabetes mellitus has been associated with an increased risk of neurodegenerative disease, such as Alzheimer's disease and Parkinson's disease, and studies have shown that metabolic dysfunction and abnormalities surrounding insulin signaling may underlie disease progression. Naturally, "anti-insulin resistance" therapy has emerged as a novel paradigm in the therapy of neurodegenerative diseases. Indeed, incretin agonists, which stimulate pancreatic insulin secretion, reduce dopaminergic neuronal loss and suppress Parkinson's disease disease progression in clinical trials. Similar studies are ongoing also in Alzheimer's disease. This paper focuses on critical issues in "immunotherapy" and "anti-insulin resistance" therapy in relation to therapeutic strategies against neurodegenerative disease, and more importantly, how they might merge mechanistically at the point of suppression of protein aggregation, raising the possibility that combined immunotherapy and "anti-insulin resistance" therapy may be superior to either monotherapy.
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Affiliation(s)
- Yoshiki Takamatsu
- Tokyo Metropolitan Institute of Medical Sciences, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-0057 Japan
| | - Gilbert Ho
- The PCND Neuroscience Research Institute, Poway, CA 92064 USA
| | - Wakako Koike
- Tokyo Metropolitan Institute of Medical Sciences, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-0057 Japan
| | - Shuei Sugama
- Department of Physiology, Nippon Medical School, Tokyo, 113-8602 Japan
| | - Takato Takenouchi
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8634 Japan
| | - Masaaki Waragai
- Tokyo Metropolitan Institute of Medical Sciences, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-0057 Japan
| | - Jianshe Wei
- Institute for Brain Sciences Research, School of Life Sciences, Henan University, Kaifeng, 475004 China
| | - Kazunari Sekiyama
- Tokyo Metropolitan Institute of Medical Sciences, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-0057 Japan
| | - Makoto Hashimoto
- Tokyo Metropolitan Institute of Medical Sciences, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-0057 Japan
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19
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Del Turco D, Paul MH, Schlaudraff J, Hick M, Endres K, Müller UC, Deller T. Region-Specific Differences in Amyloid Precursor Protein Expression in the Mouse Hippocampus. Front Mol Neurosci 2016; 9:134. [PMID: 27965537 PMCID: PMC5126089 DOI: 10.3389/fnmol.2016.00134] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/15/2016] [Indexed: 12/20/2022] Open
Abstract
The physiological role of amyloid precursor protein (APP) has been extensively investigated in the rodent hippocampus. Evidence suggests that APP plays a role in synaptic plasticity, dendritic and spine morphogenesis, neuroprotection and—at the behavioral level—hippocampus-dependent forms of learning and memory. Intriguingly, however, studies focusing on the role of APP in synaptic plasticity have reported diverging results and considerable differences in effect size between the dentate gyrus (DG) and area CA1 of the mouse hippocampus. We speculated that regional differences in APP expression could underlie these discrepancies and studied the expression of APP in both regions using immunostaining, in situ hybridization (ISH), and laser microdissection (LMD) in combination with quantitative reverse transcription polymerase chain reaction (RT-qPCR) and western blotting. In sum, our results show that APP is approximately 1.7-fold higher expressed in pyramidal cells of Ammon’s horn than in granule cells of the DG. This regional difference in APP expression may explain why loss-of-function approaches using APP-deficient mice revealed a role for APP in Hebbian plasticity in area CA1, whereas this could not be shown in the DG of the same APP mutants.
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Affiliation(s)
- Domenico Del Turco
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt, Germany
| | - Mandy H Paul
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt, Germany
| | - Jessica Schlaudraff
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt, Germany
| | - Meike Hick
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-UniversityFrankfurt, Germany; Institute of Pharmacy and Molecular Biotechnology (IPMB), Heidelberg UniversityHeidelberg, Germany
| | - Kristina Endres
- Clinic for Psychiatry and Psychotherapy, University Medical Center Mainz Mainz, Germany
| | - Ulrike C Müller
- Institute of Pharmacy and Molecular Biotechnology (IPMB), Heidelberg University Heidelberg, Germany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt, Germany
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20
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Manassero G, Guglielmotto M, Zamfir R, Borghi R, Colombo L, Salmona M, Perry G, Odetti P, Arancio O, Tamagno E, Tabaton M. Beta-amyloid 1-42 monomers, but not oligomers, produce PHF-like conformation of Tau protein. Aging Cell 2016; 15:914-23. [PMID: 27406053 PMCID: PMC5013016 DOI: 10.1111/acel.12500] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2016] [Indexed: 01/14/2023] Open
Abstract
The mechanistic relationship between amyloid β1-42 (Aβ1-42) and the alteration of Tau protein are debated. We investigated the effect of Aβ1-42 monomers and oligomers on Tau, using mice expressing wild-type human Tau that do not spontaneously develop Tau pathology. After intraventricular injection of Aβ1-42, mice were sacrificed after 3 h or 4 days. The short-lasting treatment with Aβ monomers, but not oligomers, showed a conformational PHF-like change of Tau, together with hyperphosphorylation. The same treatment induced increase in concentration of GSK3 and MAP kinases. The inhibition of the kinases rescued the Tau changes. Aβ monomers increased the levels of total Tau, through the inhibition of proteasomal degradation. Aβ oligomers reproduced all the aforementioned alterations only after 4 days of treatment. It is known that Aβ1-42 monomers foster synaptic activity. Our results suggest that Aβ monomers physiologically favor Tau activity and dendritic sprouting, whereas their excess causes Tau pathology. Moreover, our study indicates that anti-Aβ therapies should be targeted to Aβ1-42 monomers too.
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Affiliation(s)
- Giusi Manassero
- Department of Neuroscience University of Torino via Cherasco 15 10126 Torino Italy
- Neuroscience Institute of Cavalieri Ottolenghi Foundation (NICO) University of Torino Regione Gonzole 1010043 OrbassanoTorino Italy
- Unit of Geriatric Medicine Department of Internal Medicine and Medical Specialties (DIMI) University of Genova Viale Benedetto XV, 616132 Genova Italy
| | - Michela Guglielmotto
- Department of Neuroscience University of Torino via Cherasco 15 10126 Torino Italy
- Neuroscience Institute of Cavalieri Ottolenghi Foundation (NICO) University of Torino Regione Gonzole 1010043 OrbassanoTorino Italy
| | - Raluca Zamfir
- Neuroscience Institute of Cavalieri Ottolenghi Foundation (NICO) University of Torino Regione Gonzole 1010043 OrbassanoTorino Italy
| | - Roberta Borghi
- Unit of Geriatric Medicine Department of Internal Medicine and Medical Specialties (DIMI) University of Genova Viale Benedetto XV, 616132 Genova Italy
| | - Laura Colombo
- Department of Molecular Biochemistry and Pharmacology IRCCS‐Istituto di Ricerche Farmacologiche ‘Mario Negri’ Via Giuseppe La Masa 19, 20156 Milan Italy
| | - Mario Salmona
- Department of Molecular Biochemistry and Pharmacology IRCCS‐Istituto di Ricerche Farmacologiche ‘Mario Negri’ Via Giuseppe La Masa 19, 20156 Milan Italy
| | - George Perry
- College of Sciences The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA
| | - Patrizio Odetti
- Unit of Geriatric Medicine Department of Internal Medicine and Medical Specialties (DIMI) University of Genova Viale Benedetto XV, 616132 Genova Italy
- IRCCS San Martino‐IST University of Genova Viale Benedetto XV, 616132 Genova Italy
| | - Ottavio Arancio
- Department of Pathology and Cell Biology Taub Institute for Research on Alzheimer's Disease and the Aging Brain Columbia University 630 West 168th Street, P&S 12‐420D New York NY 10032 USA
| | - Elena Tamagno
- Department of Neuroscience University of Torino via Cherasco 15 10126 Torino Italy
- Neuroscience Institute of Cavalieri Ottolenghi Foundation (NICO) University of Torino Regione Gonzole 1010043 OrbassanoTorino Italy
| | - Massimo Tabaton
- Unit of Geriatric Medicine Department of Internal Medicine and Medical Specialties (DIMI) University of Genova Viale Benedetto XV, 616132 Genova Italy
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21
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Kepp KP. Alzheimer's disease due to loss of function: A new synthesis of the available data. Prog Neurobiol 2016; 143:36-60. [PMID: 27327400 DOI: 10.1016/j.pneurobio.2016.06.004] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 06/10/2016] [Accepted: 06/11/2016] [Indexed: 12/11/2022]
Abstract
Alzheimer's Disease (AD) is a highly complex disease involving a broad range of clinical, cellular, and biochemical manifestations that are currently not understood in combination. This has led to many views of AD, e.g. the amyloid, tau, presenilin, oxidative stress, and metal hypotheses. The amyloid hypothesis has dominated the field with its assumption that buildup of pathogenic β-amyloid (Aβ) peptide causes disease. This paradigm has been criticized, yet most data suggest that Aβ plays a key role in the disease. Here, a new loss-of-function hypothesis is synthesized that accounts for the anomalies of the amyloid hypothesis, e.g. the curious pathogenicity of the Aβ42/Aβ40 ratio, the loss of Aβ caused by presenilin mutation, the mixed phenotypes of APP mutations, the poor clinical-biochemical correlations for genetic variant carriers, and the failure of Aβ reducing drugs. The amyloid-loss view accounts for recent findings on the structure and chemical features of Aβ variants and their coupling to human patient data. The lost normal function of APP/Aβ is argued to be metal transport across neuronal membranes, a view with no apparent anomalies and substantially more explanatory power than the gain-of-function amyloid hypothesis. In the loss-of-function scenario, the central event of Aβ aggregation is interpreted as a loss of soluble, functional monomer Aβ rather than toxic overload of oligomers. Accordingly, new research models and treatment strategies should focus on remediation of the functional amyloid balance, rather than strict containment of Aβ, which, for reasons rationalized in this review, has failed clinically.
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Affiliation(s)
- Kasper P Kepp
- Technical University of Denmark, DTU Chemistry, DK-2800 Kongens Lyngby, Denmark.
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22
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APP Receptor? To Be or Not To Be. Trends Pharmacol Sci 2016; 37:390-411. [PMID: 26837733 DOI: 10.1016/j.tips.2016.01.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/07/2016] [Accepted: 01/11/2016] [Indexed: 11/22/2022]
Abstract
Amyloid precursor protein (APP) and its metabolites play a key role in Alzheimer's disease pathogenesis. The idea that APP may function as a receptor has gained momentum based on its structural similarities to type I transmembrane receptors and the identification of putative APP ligands. We review the recent experimental evidence in support of this notion and discuss how this concept is viewed in the field. Specifically, we focus on the structural and functional characteristics of APP as a cell surface receptor, and on its interaction with adaptors and signaling proteins. We also address the importance of APP function as a receptor in Alzheimer's disease etiology and discuss how this function might be potentially important for the development of novel therapeutic approaches.
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23
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Vnencak M, Paul MH, Hick M, Schwarzacher SW, Del Turco D, Müller UC, Deller T, Jedlicka P. Deletion of the amyloid precursor-like protein 1 (APLP1) enhances excitatory synaptic transmission, reduces network inhibition but does not impair synaptic plasticity in the mouse dentate gyrus. J Comp Neurol 2015; 523:1717-29. [PMID: 25728909 DOI: 10.1002/cne.23766] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 02/21/2015] [Accepted: 02/23/2015] [Indexed: 01/02/2023]
Abstract
Amyloid precursor-like protein 1 (APLP1) is a transmembrane synaptic protein belonging to the amyloid precursor protein (APP) gene family. Although the role of this gene family-in particular of APP-has been intensely studied in the context of Alzheimer's disease, the physiological roles of its family members remain poorly understood. In particular, the function of APLP1, which is predominantly expressed in the nervous system, has remained enigmatic. Since APP has been implicated in synaptic plasticity, we wondered whether APLP1 could play a similar role. First, using in situ hybridization and laser microdissection combined with reverse transcription-quantitative polymerase chain reaction (PCR) we observed that Aplp1 mRNA is highly expressed in dentate granule cells. Having this examined, we studied synaptic plasticity at the perforant path-granule cell synapses in the dentate gyrus of APLP1-deficient mice in vivo. Analysis of field excitatory postsynaptic potentials evoked by stimulation of perforant path fibers revealed increased excitatory transmission in APLP1-deficient mice. Moreover, we observed decreased paired-pulse inhibition of population spikes indicating a decrease in network inhibition upon deletion of APLP1. In contrast, short-term presynaptic plasticity (STP) as well as long-term synaptic plasticity (LTP) was unchanged in the absence of APLP1. Based on these results we conclude that APLP1 deficiency on its own does not lead to defects in synaptic plasticity, but affects synaptic transmission and network inhibition in the dentate gyrus.
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Affiliation(s)
- Matej Vnencak
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University, Frankfurt am Main, Germany
| | - Mandy H Paul
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University, Frankfurt am Main, Germany
| | - Meike Hick
- Department of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Stephan W Schwarzacher
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University, Frankfurt am Main, Germany
| | - Domenico Del Turco
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University, Frankfurt am Main, Germany
| | - Ulrike C Müller
- Department of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University, Frankfurt am Main, Germany
| | - Peter Jedlicka
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University, Frankfurt am Main, Germany
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24
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Cousins SL, Dai W, Stephenson FA. APLP1 and APLP2, members of the APP family of proteins, behave similarly to APP in that they associate with NMDA receptors and enhance NMDA receptor surface expression. J Neurochem 2015; 133:879-85. [PMID: 25683482 DOI: 10.1111/jnc.13063] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 02/02/2015] [Accepted: 02/06/2015] [Indexed: 11/30/2022]
Abstract
The function of amyloid precursor protein (APP) is unknown, although the discovery that it contributes to the regulation of surface expression of N-methyl-D-aspartate (NMDA) receptors has afforded new insights into its functional significance. Since APP is a member of a gene family that contains two other members, amyloid precursor-like proteins 1 and 2 (APLP1 and APLP2), it is important to determine if the related APP proteins possess the same properties as APP with respect to their interactions with NMDA receptors. Following expression in mammalian cells, both APLP1 and APLP2 behaved similarly to APP in that they both co-immunoprecipitated with the two major NMDA receptor subtypes, GluN1/GluN2A and GluN1/GluN2B, via interaction with the obligatory GluN1 subunit. Immunoprecipitations from detergent extracts of adult mammalian brain showed co-immunoprecipitation of APLP1 and APLP2 with GluN2A- and GluN2B-containing NMDA receptors. Furthermore, similarly to APP, APLP1 and APLP2 both enhanced GluN1/GluN2A and GluN1/GluN2B cell surface expression. Thus, all the three members of the APP gene family behave similarly in that they each contribute to the regulation of cell surface NMDA receptor homoeostasis. Amyloid precursor protein (APP) has been shown to associate with N-methyl-d-aspartate (NMDA) receptors and to enhance their cell surface expression. Here, we show that the other members of the APP family, APLP1 and APLP2, behave similarly to APP in that they both associate with assembled NMDA receptors in the endoplasmic reticulum via their interaction with the NMDA receptor subunit, GluN1 and, they enhance receptor cell surface expression. Alternative scenarios are depicted since it is to be determined if respective associations are direct.
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Affiliation(s)
| | - Wei Dai
- University College London School of Pharmacy, London, UK
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25
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Amyloid precursor protein dimerization and synaptogenic function depend on copper binding to the growth factor-like domain. J Neurosci 2014; 34:11159-72. [PMID: 25122912 DOI: 10.1523/jneurosci.0180-14.2014] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Accumulating evidence suggests that the copper-binding amyloid precursor protein (APP) has an essential synaptic function. APP synaptogenic function depends on trans-directed dimerization of the extracellular E1 domain encompassing a growth factor-like domain (GFLD) and a copper-binding domain (CuBD). Here we report the 1.75 Å crystal structure of the GFLD in complex with a copper ion bound with high affinity to an extended hairpin loop at the dimerization interface. In coimmunoprecipitation assays copper binding promotes APP interaction, whereas mutations in the copper-binding sites of either the GFLD or CuBD result in a drastic reduction in APP cis-orientated dimerization. We show that copper is essential and sufficient to induce trans-directed dimerization of purified APP. Furthermore, a mixed culture assay of primary neurons with HEK293 cells expressing different APP mutants revealed that APP potently promotes synaptogenesis depending on copper binding to the GFLD. Together, these findings demonstrate that copper binding to the GFLD of APP is required for APP cis-/trans-directed dimerization and APP synaptogenic function. Thus, neuronal activity or disease-associated changes in copper homeostasis likely go along with altered APP synaptic function.
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26
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Scharnagl C, Pester O, Hornburg P, Hornburg D, Götz A, Langosch D. Side-chain to main-chain hydrogen bonding controls the intrinsic backbone dynamics of the amyloid precursor protein transmembrane helix. Biophys J 2014; 106:1318-26. [PMID: 24655507 DOI: 10.1016/j.bpj.2014.02.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 01/28/2014] [Accepted: 02/07/2014] [Indexed: 01/19/2023] Open
Abstract
Many transmembrane helices contain serine and/or threonine residues whose side chains form intrahelical H-bonds with upstream carbonyl oxygens. Here, we investigated the impact of threonine side-chain/main-chain backbonding on the backbone dynamics of the amyloid precursor protein transmembrane helix. This helix consists of a N-terminal dimerization region and a C-terminal cleavage region, which is processed by γ-secretase to a series of products. Threonine mutations within this transmembrane helix are known to alter the cleavage pattern, which can lead to early-onset Alzheimer's disease. Circular dichroism spectroscopy and amide exchange experiments of synthetic transmembrane domain peptides reveal that mutating threonine enhances the flexibility of this helix. Molecular dynamics simulations show that the mutations reduce intrahelical amide H-bonding and H-bond lifetimes. In addition, the removal of side-chain/main-chain backbonding distorts the helix, which alters bending and rotation at a diglycine hinge connecting the dimerization and cleavage regions. We propose that the backbone dynamics of the substrate profoundly affects the way by which the substrate is presented to the catalytic site within the enzyme. Changing this conformational flexibility may thus change the pattern of proteolytic processing.
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Affiliation(s)
| | - Oxana Pester
- Munich Center for Integrated Protein Science (CIPS(M)) at Lehrstuhl Chemie der Biopolymere, Technische Universität München, Freising, Germany
| | - Philipp Hornburg
- Fakultät für Physik E14, Technische Universität München, Freising, Germany
| | - Daniel Hornburg
- Fakultät für Physik E14, Technische Universität München, Freising, Germany
| | - Alexander Götz
- Munich Center for Integrated Protein Science (CIPS(M)) at Lehrstuhl Chemie der Biopolymere, Technische Universität München, Freising, Germany
| | - Dieter Langosch
- Munich Center for Integrated Protein Science (CIPS(M)) at Lehrstuhl Chemie der Biopolymere, Technische Universität München, Freising, Germany
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27
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Mayer MC, Kaden D, Schauenburg L, Hancock MA, Voigt P, Roeser D, Barucker C, Than ME, Schaefer M, Multhaup G. Novel zinc-binding site in the E2 domain regulates amyloid precursor-like protein 1 (APLP1) oligomerization. J Biol Chem 2014; 289:19019-30. [PMID: 24855651 DOI: 10.1074/jbc.m114.570382] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The amyloid precursor protein (APP) and the APP-like proteins 1 and 2 (APLP1 and APLP2) are a family of multidomain transmembrane proteins possessing homo- and heterotypic contact sites in their ectodomains. We previously reported that divalent metal ions dictate the conformation of the extracellular APP E2 domain (Dahms, S. O., Könnig, I., Roeser, D., Gührs, K.-H., Mayer, M. C., Kaden, D., Multhaup, G., and Than, M. E. (2012) J. Mol. Biol. 416, 438-452), but unresolved is the nature and functional importance of metal ion binding to APLP1 and APLP2. We found here that zinc ions bound to APP and APLP1 E2 domains and mediated their oligomerization, whereas the APLP2 E2 domain interacted more weakly with zinc possessing a less surface-exposed zinc-binding site, and stayed monomeric. Copper ions bound to E2 domains of all three proteins. Fluorescence resonance energy transfer (FRET) analyses examined the effect of metal ion binding to APP and APLPs in the cellular context in real time. Zinc ions specifically induced APP and APLP1 oligomerization and forced APLP1 into multimeric clusters at the plasma membrane consistent with zinc concentrations in the blood and brain. The observed effects were mediated by a novel zinc-binding site within the APLP1 E2 domain as APLP1 deletion mutants revealed. Based upon its cellular localization and its dominant response to zinc ions, APLP1 is mainly affected by extracellular zinc among the APP family proteins. We conclude that zinc binding and APP/APLP oligomerization are intimately linked, and we propose that this represents a novel mechanism for regulating APP/APLP protein function at the molecular level.
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Affiliation(s)
- Magnus C Mayer
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
| | - Daniela Kaden
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
| | - Linda Schauenburg
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
| | - Mark A Hancock
- the Department of Pharmacology and Therapeutics, McGill University Montreal, Montreal, Quebec H3G 1Y6, Canada
| | - Philipp Voigt
- the Molekulare Pharmakologie und Zellbiologie, Thielallee 67-73, Neurowissenschaftliches Forschungszentrum, Charité-Universitätsmedizin Berlin, 14195 Berlin, Germany
| | - Dirk Roeser
- the Leibniz Institute for Age Research, Protein Crystallography Group, Fritz Lipmann Institute, Beutenbergstrasse 11, 07745 Jena, Germany, and
| | - Christian Barucker
- the Department of Pharmacology and Therapeutics, McGill University Montreal, Montreal, Quebec H3G 1Y6, Canada
| | - Manuel E Than
- the Leibniz Institute for Age Research, Protein Crystallography Group, Fritz Lipmann Institute, Beutenbergstrasse 11, 07745 Jena, Germany, and
| | - Michael Schaefer
- the Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Medizinische Fakultät der Universität Leipzig, Härtelstrasse 16-18, 04107 Leipzig, Germany
| | - Gerhard Multhaup
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany, the Department of Pharmacology and Therapeutics, McGill University Montreal, Montreal, Quebec H3G 1Y6, Canada,
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28
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Coburger I, Hoefgen S, Than ME. The structural biology of the amyloid precursor protein APP – a complex puzzle reveals its multi-domain architecture. Biol Chem 2014; 395:485-98. [DOI: 10.1515/hsz-2013-0280] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 02/04/2014] [Indexed: 01/10/2023]
Abstract
Abstract
The amyloid precursor protein (APP) and its processing are widely believed to be central for the etiology of Alzheimer’s disease (AD) and appear essential for neuronal development and cell homeostasis in mammals. Many studies show the proteolysis of APP by the proteases α-, β- and γ-secretase, functional aspects of the protein and the structure of individual domains. It is, however, largely unclear and currently also widely debated of how the structures of individual domains and their interactions determine the observed functionalities of APP and how they are arranged within the three-dimensional architecture of the entire protein. Further unanswered questions relate to the physiologic function of APP, the regulation of its proteolytic processing and the structural and functional effect of its cellular trafficking and processing. In this review, we summarize our current understanding of the structure-function-relationship of the multi-domain protein APP. This type-I transmembrane protein consists of the two folded E1 and E2 segments that are connected to one another and to the single transmembrane helix by flexible segments and likely fulfills several independent functions.
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29
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Dimitrov M, Alattia JR, Lemmin T, Lehal R, Fligier A, Houacine J, Hussain I, Radtke F, Dal Peraro M, Beher D, Fraering PC. Alzheimer's disease mutations in APP but not γ-secretase modulators affect epsilon-cleavage-dependent AICD production. Nat Commun 2014; 4:2246. [PMID: 23907250 DOI: 10.1038/ncomms3246] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 07/03/2013] [Indexed: 12/29/2022] Open
Abstract
Pathological amino-acid substitutions in the amyloid precursor protein (APP) and chemical γ-secretase modulators affect the processing of APP by the γ-secretase complex and the production of the amyloid-beta peptide Aβ42, the accumulation of which is considered causative of Alzheimer's disease. Here we demonstrate that mutations in the transmembrane domain of APP causing aggressive early-onset familial Alzheimer's disease affect both γ- and ε-cleavage sites, by raising the Aβ42/40 ratio and inhibiting the production of AICD50-99, one of the two physiological APP intracellular domains (ICDs). This is in sharp contrast to γ-secretase modulators, which shift Aβ42 production towards the shorter Aβ38, but unequivocally spare the ε-site and APP- and Notch-ICDs production. Molecular simulations suggest that familial Alzheimer's disease mutations modulate the flexibility of the APP transmembrane domain and the presentation of its γ-site, modifying at the same time, the solvation of the ε-site.
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Affiliation(s)
- Mitko Dimitrov
- Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, CH1015 Lausanne, Switzerland
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30
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Voss M, Schröder B, Fluhrer R. Mechanism, specificity, and physiology of signal peptide peptidase (SPP) and SPP-like proteases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2828-39. [PMID: 24099004 DOI: 10.1016/j.bbamem.2013.03.033] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 03/25/2013] [Accepted: 03/29/2013] [Indexed: 01/09/2023]
Abstract
Signal peptide peptidase (SPP) and the homologous SPP-like (SPPL) proteases SPPL2a, SPPL2b, SPPL2c and SPPL3 belong to the family of GxGD intramembrane proteases. SPP/SPPLs selectively cleave transmembrane domains in type II orientation and do not require additional co-factors for proteolytic activity. Orthologues of SPP and SPPLs have been identified in other vertebrates, plants, and eukaryotes. In line with their diverse subcellular localisations ranging from the ER (SPP, SPPL2c), the Golgi (SPPL3), the plasma membrane (SPPL2b) to lysosomes/late endosomes (SPPL2a), the different members of the SPP/SPPL family seem to exhibit distinct functions. Here, we review the substrates of these proteases identified to date as well as the current state of knowledge about the physiological implications of these proteolytic events as deduced from in vivo studies. Furthermore, the present knowledge on the structure of intramembrane proteases of the SPP/SPPL family, their cleavage mechanism and their substrate requirements are summarised. This article is part of a Special Issue entitled: Intramembrane Proteases.
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Affiliation(s)
- Matthias Voss
- Adolf Butenandt Institute for Biochemistry, Ludwig-Maximilians University Munich, Schillerstr. 44, 80336 Munich, Germany
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31
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The Cleavage Domain of the Amyloid Precursor Protein Transmembrane Helix Does Not Exhibit Above-Average Backbone Dynamics. Chembiochem 2013; 14:1943-8. [DOI: 10.1002/cbic.201300322] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Indexed: 11/07/2022]
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32
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Song Y, Hustedt EJ, Brandon S, Sanders CR. Competition between homodimerization and cholesterol binding to the C99 domain of the amyloid precursor protein. Biochemistry 2013; 52:5051-64. [PMID: 23865807 DOI: 10.1021/bi400735x] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The 99-residue transmembrane C-terminal domain (C99, also known as β-CTF) of the amyloid precursor protein (APP) is the product of the β-secretase cleavage of the full-length APP and is the substrate for γ-secretase cleavage. The latter cleavage releases the amyloid-β polypeptides that are closely associated with Alzheimer's disease. C99 is thought to form homodimers; however, the free energy in favor of dimerization has not previously been quantitated. It was also recently documented that cholesterol forms a 1:1 complex with monomeric C99 in bicelles. Here, the affinities for both homodimerization and cholesterol binding to C99 were measured in bilayered lipid vesicles using both electron paramagnetic resonance (EPR) and Förster resonance energy transfer (FRET) methods. Homodimerization and cholesterol binding were seen to be competitive processes that center on the transmembrane G₇₀₀XXXG₇₀₄XXXG₇₀₈ glycine-zipper motif and adjacent Gly709. On one hand, the observed Kd for cholesterol binding (Kd = 2.7 ± 0.3 mol %) is on the low end of the physiological cholesterol concentration range in mammalian cell membranes. On the other hand, the observed K(d) for homodimerization (K(d) = 0.47 ± 0.15 mol %) likely exceeds the physiological concentration range for C99. These results suggest that the 1:1 cholesterol/C99 complex will be more highly populated than C99 homodimers under most physiological conditions. These observations are of relevance for understanding the γ-secretase cleavage of C99.
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Affiliation(s)
- Yuanli Song
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
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33
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Pester O, Barrett PJ, Hornburg D, Hornburg P, Pröbstle R, Widmaier S, Kutzner C, Dürrbaum M, Kapurniotu A, Sanders CR, Scharnagl C, Langosch D. The backbone dynamics of the amyloid precursor protein transmembrane helix provides a rationale for the sequential cleavage mechanism of γ-secretase. J Am Chem Soc 2013; 135:1317-29. [PMID: 23265086 PMCID: PMC3560327 DOI: 10.1021/ja3112093] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The etiology of Alzheimer's disease depends on the relative abundance of different amyloid-β (Aβ) peptide species. These peptides are produced by sequential proteolytic cleavage within the transmembrane helix of the 99 residue C-terminal fragment of the amyloid precursor protein (C99) by the intramembrane protease γ-secretase. Intramembrane proteolysis is thought to require local unfolding of the substrate helix, which has been proposed to be cleaved as a homodimer. Here, we investigated the backbone dynamics of the substrate helix. Amide exchange experiments of monomeric recombinant C99 and of synthetic transmembrane domain peptides reveal that the N-terminal Gly-rich homodimerization domain exchanges much faster than the C-terminal cleavage region. MD simulations corroborate the differential backbone dynamics, indicate a bending motion at a diglycine motif connecting dimerization and cleavage regions, and detect significantly different H-bond stabilities at the initial cleavage sites. Our results are consistent with the following hypotheses about cleavage of the substrate: First, the GlyGly hinge may precisely position the substrate within γ-secretase such that its catalytic center must start proteolysis at the known initial cleavage sites. Second, the ratio of cleavage products formed by subsequent sequential proteolysis could be influenced by differential extents of solvation and by the stabilities of H-bonds at alternate initial sites. Third, the flexibility of the Gly-rich domain may facilitate substrate movement within the enzyme during sequential proteolysis. Fourth, dimerization may affect substrate processing by decreasing the dynamics of the dimerization region and by increasing that of the C-terminal part of the cleavage region.
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Affiliation(s)
- Oxana Pester
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Paul J. Barrett
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, Tennessee USA 37232-8725
| | - Daniel Hornburg
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Philipp Hornburg
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Rasmus Pröbstle
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Simon Widmaier
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Christoph Kutzner
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Milena Dürrbaum
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Aphrodite Kapurniotu
- Fachgebiet Peptidbiochemie, Technische Universität München, Emil-Erlenmeyer-Forum 5, 85354 Freising, Germany
| | - Charles R. Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, Tennessee USA 37232-8725
| | - Christina Scharnagl
- Fakultät für Physik E14, Technische Universität München, Maximus-von-Imhof-Forum 4, 85354 Freising, Germany
| | - Dieter Langosch
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
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34
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Peters HL, Tuli A, Wang X, Liu C, Pan Z, Ouellette MM, Hollingsworth MA, Macdonald RG, Solheim JC. Relevance of amyloid precursor-like protein 2 C-terminal fragments in pancreatic cancer cells. Int J Oncol 2012; 41:1464-74. [PMID: 22797723 PMCID: PMC3482291 DOI: 10.3892/ijo.2012.1553] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 05/25/2012] [Indexed: 12/21/2022] Open
Abstract
In some cellular systems, particularly neurons, amyloid precursor-like protein 2 (APLP2), and its highly homologous family member amyloid precursor protein (APP), have been linked to cellular growth. APLP2 and APP undergo regulated intramembrane proteolysis to produce C-terminal fragments. In this study, we found comprehensive expression of APLP2 C-terminal fragments in a panel of pancreatic cancer cell lines; however, APP C-terminal fragments were notably limited to the BxPC3 cell line. Extensive glycosaminoglycan modification on APLP2 was also found in the majority of pancreatic cancer cell lines. Glycosaminoglycan-modified and -unmodified APLP2, and particularly APLP2 C-terminal fragments, also demonstrated increased expression in oncogene-transformed pancreatic ductal cells. Additionally, elevated APLP2 levels were confirmed in human pancreatic cancer tissue. Downregulation of APLP2 and APP expression, alone or in combination, caused a decrease in the growth of a pancreatic cancer cell line with representatively low APP C-terminal fragment expression, the S2-013 cell line. Furthermore, we found that treatment with β-secretase inhibitors to block formation of APLP2 C-terminal fragments decreased the growth and viability of S2-013 cells, without affecting the survival of a non-transformed pancreatic ductal cell line. In conclusion, our studies demonstrate that abundant APLP2, but not APP, C-terminal fragment expression is conserved in pancreatic cancer cell lines; however, APP and APLP2 equally regulated the growth of S2-013 pancreatic cancer cells. Chiefly, our discoveries establish a role for APLP2 in the growth of pancreatic cancer cells and show that inhibitors preventing APLP2 cleavage reduce the viability of pancreatic cancer cells.
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Affiliation(s)
- Haley L Peters
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
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35
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Libeu CAP, Descamps O, Zhang Q, John V, Bredesen DE. Altering APP proteolysis: increasing sAPPalpha production by targeting dimerization of the APP ectodomain. PLoS One 2012; 7:e40027. [PMID: 22768208 PMCID: PMC3386930 DOI: 10.1371/journal.pone.0040027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 06/04/2012] [Indexed: 12/13/2022] Open
Abstract
One of the events associated with Alzheimer's disease is the dysregulation of α- versus β-cleavage of the amyloid precursor protein (APP). The product of α-cleavage (sAPPα) has neuroprotective properties, while Aβ1-42 peptide, a product of β-cleavage, is neurotoxic. Dimerization of APP has been shown to influence the relative rate of α- and β- cleavage of APP. Thus finding compounds that interfere with dimerization of the APP ectodomain and increase the α-cleavage of APP could lead to the development of new therapies for Alzheimer's disease. Examining the intrinsic fluorescence of a fragment of the ectodomain of APP, which dimerizes through the E2 and Aβ-cognate domains, revealed significant changes in the fluorescence of the fragment upon binding of Aβ oligomers--which bind to dimers of the ectodomain--and Aβ fragments--which destabilize dimers of the ectodomain. This technique was extended to show that RERMS-containing peptides (APP(695) 328-332), disulfiram, and sulfiram also inhibit dimerization of the ectodomain fragment. This activity was confirmed with small angle x-ray scattering. Analysis of the activity of disulfiram and sulfiram in an AlphaLISA assay indicated that both compounds significantly enhance the production of sAPPα by 7W-CHO and B103 neuroblastoma cells. These observations demonstrate that there is a class of compounds that modulates the conformation of the APP ectodomain and influences the ratio of α- to β-cleavage of APP. These compounds provide a rationale for the development of a new class of therapeutics for Alzheimer's disease.
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Affiliation(s)
- Clare A Peters Libeu
- Buck Institute for Research on Aging, Novato, California, United States of America.
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36
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Amyloid precursor protein is required for normal function of the rod and cone pathways in the mouse retina. PLoS One 2012; 7:e29892. [PMID: 22279552 PMCID: PMC3261162 DOI: 10.1371/journal.pone.0029892] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 12/07/2011] [Indexed: 01/01/2023] Open
Abstract
Amyloid precursor protein (APP) is a transmembrane glycoprotein frequently studied for its role in Alzheimer's disease. Our recent study in APP knockout (KO) mice identified an important role for APP in modulating normal neuronal development in the retina. However the role APP plays in the adult retina and whether it is required for vision is unknown. In this study we evaluated the role of APP in retinal function and morphology comparing adult wildtype (WT) and APP-KO mice. APP was expressed on neuronal cells of the inner retina, including horizontal, cone bipolar, amacrine and ganglion cells in WT mice. The function of the retina was assessed using the electroretinogram and although the rod photoreceptor responses were similar in APP-KO and WT mice, the post-photoreceptor, inner retinal responses of both the rod and cone pathways were reduced in APP-KO mice. These changes in inner retinal function did not translate to a substantial change in visual acuity as assessed using the optokinetic response or to changes in the gross cellular structure of the retina. These findings indicate that APP is not required for basic visual function, but that it is involved in modulating inner retinal circuitry.
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37
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Roles of amyloid precursor protein family members in neuroprotection, stress signaling and aging. Exp Brain Res 2011; 217:471-9. [PMID: 22086493 DOI: 10.1007/s00221-011-2932-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 10/28/2011] [Indexed: 12/24/2022]
Abstract
The roles of amyloid precursor protein (APP) family members in normal brain function are poorly understood. Under physiological conditions the majority of APP appears to be processed along the non-amyloidogenic pathway leading to the formation of the secreted N-terminal APP fragment sAPPα. This cleavage product of APP has been implicated in several physiological processes such as neuroprotection, synaptic plasticity, neurite outgrowth and synaptogenesis. In this review we focus on the role of APP family members in neuroprotection and summarize the cellular and molecular mechanisms which are believed to mediate this effect. We propose that a reduction of APP processing along the non-amyloidogenic pathway during brain aging could result in an enhanced susceptibility of neurons to cellular stress and could contribute to neurodegeneration in Alzheimer's disease.
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