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Ma L, Wang F, Chen S, Wang S, Wang Z, Xia M, Li Y, Ma H, Shang J, Zhang J. Probable Novel APP Met671Leu Mutation in a Chinese Han Family with Early-Onset Alzheimer's Disease. Neuromolecular Med 2024; 26:6. [PMID: 38504005 DOI: 10.1007/s12017-023-08770-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 11/19/2023] [Indexed: 03/21/2024]
Abstract
Familial Alzheimer's disease (AD) is a rare disease caused by autosomal-dominant mutations. APP (encoding amyloid precursor protein), PSEN1 (encoding presenilin 1), and PSEN2 (encoding presenilin 2) are the most common genes cause dominant inherited AD. This study aimed to demonstrate a Chinese early-onset AD pedigree presenting as progressive memory impairment, apraxia, visual-spatial disorders, psychobehavioral disorders, and personality changes with a novel APP gene mutation. The family contains four patients, three carries and three normal family members. The proband underwent brain magnetic resonance imaging (MRI), 18F-fludeoxyglucose positron emission tomography (18F-FDG-PET), cerebrospinal fluid amyloid detection, 18F-florbetapir (AV-45) Positron Emission Computed Tomography (PET) imaging, whole-exome sequencing and Sanger sequencing. Brain MRI images showed brain atrophy, especially in the entorhinal cortex, temporal hippocampus, and lateral ventricle dilation. The FDG-PET showed hypometabolism in the frontotemporal, parietal, and hippocampal regions. 18F-florbetapir (AV-45) PET imaging showed cerebral cortex Aβ protein deposition. The cerebrospinal fluid amyloid protein test showed Aβ42/Aβ40 ratio decreases, pathological phosphor-tau level increases. Whole-exome sequencing detected a new missense mutation of codon 671 (M671L), which was a heterozygous A to T point mutation at position 2011 (c.2011A > T) in exon 16 of the amyloid precursor protein, resulting in the replacement of methionine to Leucine. The co-separation analysis was validated in this family. The mutation was found in 3 patients, 3 clinical normal members in the family, but not in the other 3 unaffected family members, 100 unrelated normal subjects, or 100 sporadic patients with AD. This mutation was probably pathogenic and novel in a Chinese Han family with early-onset AD.
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Affiliation(s)
- Limin Ma
- Department of Health Management Center, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Fengyu Wang
- Department of Neurology, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Shuai Chen
- Department of Neurology, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Shenghui Wang
- Department of Neurology, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Zhenzhen Wang
- Department of Radiology, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Mingrong Xia
- Department of Neurology, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Yongli Li
- Department of Health Management Center, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Huimin Ma
- Department of Health Management Center, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Junkui Shang
- Department of Neurology, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Jiewen Zhang
- Department of Neurology, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China.
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Premkumar T, Sajitha Lulu S. Molecular crosstalk between COVID-19 and Alzheimer's disease using microarray and RNA-seq datasets: A system biology approach. Front Med (Lausanne) 2023; 10:1151046. [PMID: 37359008 PMCID: PMC10286240 DOI: 10.3389/fmed.2023.1151046] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 03/20/2023] [Indexed: 06/28/2023] Open
Abstract
Objective Coronavirus disease 2019 (COVID-19) is an infectious disease caused by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). The clinical and epidemiological analysis reported the association between SARS-CoV-2 and neurological diseases. Among neurological diseases, Alzheimer's disease (AD) has developed as a crucial comorbidity of SARS-CoV-2. This study aimed to understand the common transcriptional signatures between SARS-CoV-2 and AD. Materials and methods System biology approaches were used to compare the datasets of AD and COVID-19 to identify the genetic association. For this, we have integrated three human whole transcriptomic datasets for COVID-19 and five microarray datasets for AD. We have identified differentially expressed genes for all the datasets and constructed a protein-protein interaction (PPI) network. Hub genes were identified from the PPI network, and hub genes-associated regulatory molecules (transcription factors and miRNAs) were identified for further validation. Results A total of 9,500 differentially expressed genes (DEGs) were identified for AD and 7,000 DEGs for COVID-19. Gene ontology analysis resulted in 37 molecular functions, 79 cellular components, and 129 biological processes were found to be commonly enriched in AD and COVID-19. We identified 26 hub genes which includes AKT1, ALB, BDNF, CD4, CDH1, DLG4, EGF, EGFR, FN1, GAPDH, INS, ITGB1, ACTB, SRC, TP53, CDC42, RUNX2, HSPA8, PSMD2, GFAP, VAMP2, MAPK8, CAV1, GNB1, RBX1, and ITGA2B. Specific miRNA targets associated with Alzheimer's disease and COVID-19 were identified through miRNA target prediction. In addition, we found hub genes-transcription factor and hub genes-drugs interaction. We also performed pathway analysis for the hub genes and found that several cell signaling pathways are enriched, such as PI3K-AKT, Neurotrophin, Rap1, Ras, and JAK-STAT. Conclusion Our results suggest that the identified hub genes could be diagnostic biomarkers and potential therapeutic drug targets for COVID-19 patients with AD comorbidity.
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Papadopoulos N, Suelves N, Perrin F, Vadukul DM, Vrancx C, Constantinescu SN, Kienlen-Campard P. Structural Determinant of β-Amyloid Formation: From Transmembrane Protein Dimerization to β-Amyloid Aggregates. Biomedicines 2022; 10:2753. [PMID: 36359274 PMCID: PMC9687742 DOI: 10.3390/biomedicines10112753] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/18/2022] [Accepted: 10/21/2022] [Indexed: 10/03/2023] Open
Abstract
Most neurodegenerative diseases have the characteristics of protein folding disorders, i.e., they cause lesions to appear in vulnerable regions of the nervous system, corresponding to protein aggregates that progressively spread through the neuronal network as the symptoms progress. Alzheimer's disease is one of these diseases. It is characterized by two types of lesions: neurofibrillary tangles (NFTs) composed of tau proteins and senile plaques, formed essentially of amyloid peptides (Aβ). A combination of factors ranging from genetic mutations to age-related changes in the cellular context converge in this disease to accelerate Aβ deposition. Over the last two decades, numerous studies have attempted to elucidate how structural determinants of its precursor (APP) modify Aβ production, and to understand the processes leading to the formation of different Aβ aggregates, e.g., fibrils and oligomers. The synthesis proposed in this review indicates that the same motifs can control APP function and Aβ production essentially by regulating membrane protein dimerization, and subsequently Aβ aggregation processes. The distinct properties of these motifs and the cellular context regulate the APP conformation to trigger the transition to the amyloid pathology. This concept is critical to better decipher the patterns switching APP protein conformation from physiological to pathological and improve our understanding of the mechanisms underpinning the formation of amyloid fibrils that devastate neuronal functions.
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Affiliation(s)
- Nicolas Papadopoulos
- SIGN Unit, de Duve Institute, UCLouvain, 1200 Brussels, Belgium
- Ludwig Institute for Cancer Research Brussels, 1348 Brussels, Belgium
| | - Nuria Suelves
- Aging and Dementia Research Group, Cellular and Molecular (CEMO) Division, Institute of Neuroscience, UCLouvain, 1200 Brussels, Belgium
| | - Florian Perrin
- Memory Disorders Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Devkee M. Vadukul
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London SW7 2BX, UK
| | - Céline Vrancx
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, KU Leuven, 3000 Leuven, Belgium
- Department of Neurosciences, KU Leuven, 3000 Leuven, Belgium
| | - Stefan N. Constantinescu
- SIGN Unit, de Duve Institute, UCLouvain, 1200 Brussels, Belgium
- Ludwig Institute for Cancer Research Brussels, 1348 Brussels, Belgium
- Walloon Excellence in Life Sciences and Biotechnology (WELBIO), 1300 Wavre, Belgium
- Nuffield Department of Medicine, Ludwig Institute for Cancer Research, Oxford University, Oxford OX1 2JD, UK
| | - Pascal Kienlen-Campard
- Aging and Dementia Research Group, Cellular and Molecular (CEMO) Division, Institute of Neuroscience, UCLouvain, 1200 Brussels, Belgium
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Hook G, Reinheckel T, Ni J, Wu Z, Kindy M, Peters C, Hook V. Cathepsin B Gene Knockout Improves Behavioral Deficits and Reduces Pathology in Models of Neurologic Disorders. Pharmacol Rev 2022; 74:600-629. [PMID: 35710131 PMCID: PMC9553114 DOI: 10.1124/pharmrev.121.000527] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cathepsin B (CTSB) is a powerful lysosomal protease. This review evaluated CTSB gene knockout (KO) outcomes for amelioration of brain dysfunctions in neurologic diseases and aging animal models. Deletion of the CTSB gene resulted in significant improvements in behavioral deficits, neuropathology, and/or biomarkers in traumatic brain injury, ischemia, inflammatory pain, opiate tolerance, epilepsy, aging, transgenic Alzheimer's disease (AD), and periodontitis AD models as shown in 12 studies. One study found beneficial effects for double CTSB and cathepsin S KO mice in a multiple sclerosis model. Transgenic AD models using amyloid precursor protein (APP) mimicking common sporadic AD in three studies showed that CTSB KO improved memory, neuropathology, and biomarkers; two studies used APP representing rare familial AD and found no CTSB KO effect, and two studies used highly engineered APP constructs and reported slight increases in a biomarker. In clinical studies, all reports found that CTSB enzyme was upregulated in diverse neurologic disorders, including AD in which elevated CTSB was positively correlated with cognitive dysfunction. In a wide range of neurologic animal models, CTSB was also upregulated and not downregulated. Further, human genetic mutation data provided precedence for CTSB upregulation causing disease. Thus, the consilience of data is that CTSB gene KO results in improved brain dysfunction and reduced pathology through blockade of CTSB enzyme upregulation that causes human neurologic disease phenotypes. The overall findings provide strong support for CTSB as a rational drug target and for CTSB inhibitors as therapeutic candidates for a wide range of neurologic disorders. SIGNIFICANCE STATEMENT: This review provides a comprehensive compilation of the extensive data on the effects of deleting the cathepsin B (CTSB) gene in neurological and aging mouse models of brain disorders. Mice lacking the CTSB gene display improved neurobehavioral deficits, reduced neuropathology, and amelioration of neuronal cell death and inflammatory biomarkers. The significance of the compelling CTSB evidence is that the data consilience validates CTSB as a drug target for discovery of CTSB inhibitors as potential therapeutics for treating numerous neurological diseases.
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Affiliation(s)
- Gregory Hook
- American Life Science Pharmaceuticals, La Jolla, California (G.H.); Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University, Freiburg, Germany (T.R.); German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany (T.R.); German Cancer Research Center (DKFZ), Heidelberg, Germany (T.R); Center for Biological Signaling Studies BIOSS, Albert Ludwigs University, Freiburg, Germany (T.R.); Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China (J.N.); Department of Aging Science and Pharmacology, OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (Z.W); Taneja College of Pharmacy, Department of Pharmaceutical Sciences, University of South Florida, Tampa, Florida (M.K.); James A Haley VAMC, Research Service, Tampa, Florida (M.K.); Institute of Molecular Medicine and Cell Research, Faculty of Biology, Albert Ludwigs University, Freiburg, Germany (C.P.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA (V.H.); and Department of Neuroscience and Department of Pharmacology, School of Medicine, University of California, La Jolla, CA (V.H.)
| | - Thomas Reinheckel
- American Life Science Pharmaceuticals, La Jolla, California (G.H.); Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University, Freiburg, Germany (T.R.); German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany (T.R.); German Cancer Research Center (DKFZ), Heidelberg, Germany (T.R); Center for Biological Signaling Studies BIOSS, Albert Ludwigs University, Freiburg, Germany (T.R.); Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China (J.N.); Department of Aging Science and Pharmacology, OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (Z.W); Taneja College of Pharmacy, Department of Pharmaceutical Sciences, University of South Florida, Tampa, Florida (M.K.); James A Haley VAMC, Research Service, Tampa, Florida (M.K.); Institute of Molecular Medicine and Cell Research, Faculty of Biology, Albert Ludwigs University, Freiburg, Germany (C.P.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA (V.H.); and Department of Neuroscience and Department of Pharmacology, School of Medicine, University of California, La Jolla, CA (V.H.)
| | - Junjun Ni
- American Life Science Pharmaceuticals, La Jolla, California (G.H.); Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University, Freiburg, Germany (T.R.); German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany (T.R.); German Cancer Research Center (DKFZ), Heidelberg, Germany (T.R); Center for Biological Signaling Studies BIOSS, Albert Ludwigs University, Freiburg, Germany (T.R.); Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China (J.N.); Department of Aging Science and Pharmacology, OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (Z.W); Taneja College of Pharmacy, Department of Pharmaceutical Sciences, University of South Florida, Tampa, Florida (M.K.); James A Haley VAMC, Research Service, Tampa, Florida (M.K.); Institute of Molecular Medicine and Cell Research, Faculty of Biology, Albert Ludwigs University, Freiburg, Germany (C.P.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA (V.H.); and Department of Neuroscience and Department of Pharmacology, School of Medicine, University of California, La Jolla, CA (V.H.)
| | - Zhou Wu
- American Life Science Pharmaceuticals, La Jolla, California (G.H.); Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University, Freiburg, Germany (T.R.); German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany (T.R.); German Cancer Research Center (DKFZ), Heidelberg, Germany (T.R); Center for Biological Signaling Studies BIOSS, Albert Ludwigs University, Freiburg, Germany (T.R.); Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China (J.N.); Department of Aging Science and Pharmacology, OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (Z.W); Taneja College of Pharmacy, Department of Pharmaceutical Sciences, University of South Florida, Tampa, Florida (M.K.); James A Haley VAMC, Research Service, Tampa, Florida (M.K.); Institute of Molecular Medicine and Cell Research, Faculty of Biology, Albert Ludwigs University, Freiburg, Germany (C.P.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA (V.H.); and Department of Neuroscience and Department of Pharmacology, School of Medicine, University of California, La Jolla, CA (V.H.)
| | - Mark Kindy
- American Life Science Pharmaceuticals, La Jolla, California (G.H.); Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University, Freiburg, Germany (T.R.); German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany (T.R.); German Cancer Research Center (DKFZ), Heidelberg, Germany (T.R); Center for Biological Signaling Studies BIOSS, Albert Ludwigs University, Freiburg, Germany (T.R.); Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China (J.N.); Department of Aging Science and Pharmacology, OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (Z.W); Taneja College of Pharmacy, Department of Pharmaceutical Sciences, University of South Florida, Tampa, Florida (M.K.); James A Haley VAMC, Research Service, Tampa, Florida (M.K.); Institute of Molecular Medicine and Cell Research, Faculty of Biology, Albert Ludwigs University, Freiburg, Germany (C.P.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA (V.H.); and Department of Neuroscience and Department of Pharmacology, School of Medicine, University of California, La Jolla, CA (V.H.)
| | - Christoph Peters
- American Life Science Pharmaceuticals, La Jolla, California (G.H.); Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University, Freiburg, Germany (T.R.); German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany (T.R.); German Cancer Research Center (DKFZ), Heidelberg, Germany (T.R); Center for Biological Signaling Studies BIOSS, Albert Ludwigs University, Freiburg, Germany (T.R.); Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China (J.N.); Department of Aging Science and Pharmacology, OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (Z.W); Taneja College of Pharmacy, Department of Pharmaceutical Sciences, University of South Florida, Tampa, Florida (M.K.); James A Haley VAMC, Research Service, Tampa, Florida (M.K.); Institute of Molecular Medicine and Cell Research, Faculty of Biology, Albert Ludwigs University, Freiburg, Germany (C.P.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA (V.H.); and Department of Neuroscience and Department of Pharmacology, School of Medicine, University of California, La Jolla, CA (V.H.)
| | - Vivian Hook
- American Life Science Pharmaceuticals, La Jolla, California (G.H.); Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University, Freiburg, Germany (T.R.); German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany (T.R.); German Cancer Research Center (DKFZ), Heidelberg, Germany (T.R); Center for Biological Signaling Studies BIOSS, Albert Ludwigs University, Freiburg, Germany (T.R.); Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China (J.N.); Department of Aging Science and Pharmacology, OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (Z.W); Taneja College of Pharmacy, Department of Pharmaceutical Sciences, University of South Florida, Tampa, Florida (M.K.); James A Haley VAMC, Research Service, Tampa, Florida (M.K.); Institute of Molecular Medicine and Cell Research, Faculty of Biology, Albert Ludwigs University, Freiburg, Germany (C.P.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA (V.H.); and Department of Neuroscience and Department of Pharmacology, School of Medicine, University of California, La Jolla, CA (V.H.)
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5
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Vitória JJM, Trigo D, da Cruz E Silva OAB. Revisiting APP secretases: an overview on the holistic effects of retinoic acid receptor stimulation in APP processing. Cell Mol Life Sci 2022; 79:101. [PMID: 35089425 PMCID: PMC11073327 DOI: 10.1007/s00018-021-04090-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 11/18/2021] [Accepted: 12/01/2021] [Indexed: 01/03/2023]
Abstract
Alzheimer's disease (AD) is the leading cause of dementia worldwide and is characterized by the accumulation of the β-amyloid peptide (Aβ) in the brain, along with profound alterations in phosphorylation-related events and regulatory pathways. The production of the neurotoxic Aβ peptide via amyloid precursor protein (APP) proteolysis is a crucial step in AD development. APP is highly expressed in the brain and is complexly metabolized by a series of sequential secretases, commonly denoted the α-, β-, and γ-cleavages. The toxicity of resulting fragments is a direct consequence of the first cleaving event. β-secretase (BACE1) induces amyloidogenic cleavages, while α-secretases (ADAM10 and ADAM17) result in less pathological peptides. Hence this first cleavage event is a prime therapeutic target for preventing or reverting initial biochemical events involved in AD. The subsequent cleavage by γ-secretase has a reduced impact on Aβ formation but affects the peptides' aggregating capacity. An array of therapeutic strategies are being explored, among them targeting Retinoic Acid (RA) signalling, which has long been associated with neuronal health. Additionally, several studies have described altered RA levels in AD patients, reinforcing RA Receptor (RAR) signalling as a promising therapeutic strategy. In this review we provide a holistic approach focussing on the effects of isoform-specific RAR modulation with respect to APP secretases and discuss its advantages and drawbacks in subcellular AD related events.
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Affiliation(s)
- José J M Vitória
- Department of Medical Sciences, Neurosciences and Signalling Group, Institute of Biomedicine, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Diogo Trigo
- Department of Medical Sciences, Neurosciences and Signalling Group, Institute of Biomedicine, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Odete A B da Cruz E Silva
- Department of Medical Sciences, Neurosciences and Signalling Group, Institute of Biomedicine, University of Aveiro, 3810-193, Aveiro, Portugal.
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Song XJ, Zhou HY, Sun YY, Huang HC. Phosphorylation and Glycosylation of Amyloid-β Protein Precursor: The Relationship to Trafficking and Cleavage in Alzheimer's Disease. J Alzheimers Dis 2021; 84:937-957. [PMID: 34602469 DOI: 10.3233/jad-210337] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder in the central nervous system, and this disease is characterized by extracellular senile plaques and intracellular neurofibrillary tangles. Amyloid-β (Aβ) peptide is the main constituent of senile plaques, and this peptide is derived from the amyloid-β protein precursor (AβPP) through the successive cleaving by β-site AβPP-cleavage enzyme 1 (BACE1) and γ-secretase. AβPP undergoes the progress of post-translational modifications, such as phosphorylation and glycosylation, which might affect the trafficking and the cleavage of AβPP. In the recent years, about 10 phosphorylation sites of AβPP were identified, and they play complex roles in glycosylation modification and cleavage of AβPP. In this article, we introduced the transport and the cleavage pathways of AβPP, then summarized the phosphorylation and glycosylation sites of AβPP, and further discussed the links and relationship between phosphorylation and glycosylation on the pathways of AβPP trafficking and cleavage in order to provide theoretical basis for AD research.
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Affiliation(s)
- Xi-Jun Song
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China.,Research Institute of Functional Factors and Brain Science, Beijing Union University, Beijing, China
| | - He-Yan Zhou
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China.,Research Institute of Functional Factors and Brain Science, Beijing Union University, Beijing, China
| | - Yu-Ying Sun
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China.,Research Institute of Functional Factors and Brain Science, Beijing Union University, Beijing, China
| | - Han-Chang Huang
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China.,Research Institute of Functional Factors and Brain Science, Beijing Union University, Beijing, China
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An evaluation of the self-assembly enhancing properties of cell-derived hexameric amyloid-β. Sci Rep 2021; 11:11570. [PMID: 34078941 PMCID: PMC8172837 DOI: 10.1038/s41598-021-90680-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 05/04/2021] [Indexed: 12/17/2022] Open
Abstract
A key hallmark of Alzheimer’s disease is the extracellular deposition of amyloid plaques composed primarily of the amyloidogenic amyloid-β (Aβ) peptide. The Aβ peptide is a product of sequential cleavage of the Amyloid Precursor Protein, the first step of which gives rise to a C-terminal Fragment (C99). Cleavage of C99 by γ-secretase activity releases Aβ of several lengths and the Aβ42 isoform in particular has been identified as being neurotoxic. The misfolding of Aβ leads to subsequent amyloid fibril formation by nucleated polymerisation. This requires an initial and critical nucleus for self-assembly. Here, we identify and characterise the composition and self-assembly properties of cell-derived hexameric Aβ42 and show its assembly enhancing properties which are dependent on the Aβ monomer availability. Identification of nucleating assemblies that contribute to self-assembly in this way may serve as therapeutic targets to prevent the formation of toxic oligomers.
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8
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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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9
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Dimeric Transmembrane Orientations of APP/C99 Regulate γ-Secretase Processing Line Impacting Signaling and Oligomerization. iScience 2020; 23:101887. [PMID: 33367225 PMCID: PMC7749410 DOI: 10.1016/j.isci.2020.101887] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/21/2020] [Accepted: 11/25/2020] [Indexed: 12/22/2022] Open
Abstract
Amyloid precursor protein (APP) cleavage by the β-secretase produces the C99 transmembrane (TM) protein, which contains three dimerization-inducing Gly-x-x-x-Gly motifs. We demonstrate that dimeric C99 TM orientations regulate the precise cleavage lines by γ-secretase. Of all possible dimeric orientations imposed by a coiled-coil to the C99 TM domain, the dimer containing the 33Gly-x-x-x-Gly37 motif in the interface promoted the Aβ42 processing line and APP intracellular domain-dependent gene transcription, including the induction of BACE1 mRNA, enhancing amyloidogenic processing and signaling. Another orientation exhibiting the 25Gly-x-x-x-Gly29 motif in the interface favored processing to Aβ43/40. It induced significantly less gene transcription, while promoting formation of SDS-resistant "Aβ-like" oligomers, reminiscent of Aβ peptide oligomers. These required both Val24 of a pro-β motif and the 25Gly-x-x-x-Gly29 interface. Thus, crossing angles imposed by precise dimeric orientations control γ-secretase initial cleavage at Aβ48 or Aβ49, linking the former to enhanced signaling and Aβ42 production.
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10
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Langness VF, van der Kant R, Das U, Wang L, Chaves RDS, Goldstein LSB. Cholesterol-lowering drugs reduce APP processing to Aβ by inducing APP dimerization. Mol Biol Cell 2020; 32:247-259. [PMID: 33296223 PMCID: PMC8098827 DOI: 10.1091/mbc.e20-05-0345] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Amyloid beta (Aβ) is a major component of amyloid plaques, which are a key pathological hallmark found in the brains of Alzheimer’s disease (AD) patients. We show that statins are effective at reducing Aβ in human neurons from nondemented control subjects, as well as subjects with familial AD and sporadic AD. Aβ is derived from amyloid precursor protein (APP) through sequential proteolytic cleavage by BACE1 and γ-secretase. While previous studies have shown that cholesterol metabolism regulates APP processing to Aβ, the mechanism is not well understood. We used iPSC-derived neurons and bimolecular fluorescence complementation assays in transfected cells to elucidate how altering cholesterol metabolism influences APP processing. Altering cholesterol metabolism using statins decreased the generation of sAPPβ and increased levels of full-length APP (flAPP), indicative of reduced processing of APP by BACE1. We further show that statins decrease flAPP interaction with BACE1 and enhance APP dimerization. Additionally, statin-induced changes in APP dimerization and APP-BACE1 are dependent on cholesterol binding to APP. Our data indicate that statins reduce Aβ production by decreasing BACE1 interaction with flAPP and suggest that this process may be regulated through competition between APP dimerization and APP cholesterol binding.
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Affiliation(s)
- Vanessa F Langness
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093.,Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA 92037
| | - Rik van der Kant
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam de Boelelaan 1087, 1081 HV Amsterdam, The Netherlands.,Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Amsterdam UMC, De Boelelaan 1118, 1081 HZ Amsterdam, The Netherlands
| | - Utpal Das
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093.,Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA 92037
| | - Louie Wang
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093.,Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA 92037
| | - Rodrigo Dos Santos Chaves
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093.,Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA 92037
| | - Lawrence S B Goldstein
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093.,Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093.,Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, CA 92037
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11
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De Luca C, Colangelo AM, Alberghina L, Papa M. Neuro-Immune Hemostasis: Homeostasis and Diseases in the Central Nervous System. Front Cell Neurosci 2018; 12:459. [PMID: 30534057 PMCID: PMC6275309 DOI: 10.3389/fncel.2018.00459] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/12/2018] [Indexed: 01/08/2023] Open
Abstract
Coagulation and the immune system interact in several physiological and pathological conditions, including tissue repair, host defense, and homeostatic maintenance. This network plays a key role in diseases of the central nervous system (CNS) by involving several cells (CNS resident cells, platelets, endothelium, and leukocytes) and molecular pathways (protease activity, complement factors, platelet granule content). Endothelial damage prompts platelet activation and the coagulation cascade as the first physiological step to support the rescue of damaged tissues, a flawed rescuing system ultimately producing neuroinflammation. Leukocytes, platelets, and endothelial cells are sensitive to the damage and indeed can release or respond to chemokines and cytokines (platelet factor 4, CXCL4, TNF, interleukins), and growth factors (including platelet-derived growth factor, vascular endothelial growth factor, and brain-derived neurotrophic factor) with platelet activation, change in capillary permeability, migration or differentiation of leukocytes. Thrombin, plasmin, activated complement factors and matrix metalloproteinase-1 (MMP-1), furthermore, activate intracellular transduction through complement or protease-activated receptors. Impairment of the neuro-immune hemostasis network induces acute or chronic CNS pathologies related to the neurovascular unit, either directly or by the systemic activation of its main steps. Neurons, glial cells (astrocytes and microglia) and the extracellular matrix play a crucial function in a “tetrapartite” synaptic model. Taking into account the neurovascular unit, in this review we thoroughly analyzed the influence of neuro-immune hemostasis on these five elements acting as a functional unit (“pentapartite” synapse) in the adaptive and maladaptive plasticity and discuss the relevance of these events in inflammatory, cerebrovascular, Alzheimer, neoplastic and psychiatric diseases. Finally, based on the solid reviewed data, we hypothesize a model of neuro-immune hemostatic network based on protein–protein interactions. In addition, we propose that, to better understand and favor the maintenance of adaptive plasticity, it would be useful to construct predictive molecular models, able to enlighten the regulating logic of the complex molecular network, which belongs to different cellular domains. A modeling approach would help to define how nodes of the network interact with basic cellular functions, such as mitochondrial metabolism, autophagy or apoptosis. It is expected that dynamic systems biology models might help to elucidate the fine structure of molecular events generated by blood coagulation and neuro-immune responses in several CNS diseases, thereby opening the way to more effective treatments.
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Affiliation(s)
- Ciro De Luca
- Laboratory of Morphology of Neuronal Network, Department of Public Medicine, University of Campania-Luigi Vanvitelli, Naples, Italy
| | - Anna Maria Colangelo
- Laboratory of Neuroscience "R. Levi-Montalcini", Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy.,SYSBIO Centre of Systems Biology, University of Milano-Bicocca, Milan, Italy
| | - Lilia Alberghina
- Laboratory of Neuroscience "R. Levi-Montalcini", Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy.,SYSBIO Centre of Systems Biology, University of Milano-Bicocca, Milan, Italy
| | - Michele Papa
- Laboratory of Morphology of Neuronal Network, Department of Public Medicine, University of Campania-Luigi Vanvitelli, Naples, Italy.,SYSBIO Centre of Systems Biology, University of Milano-Bicocca, Milan, Italy
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12
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Luu L, Ciccotosto GD, Vella LJ, Cheng L, Roisman LC, Multhaup G, Hill AF, Munter LM, Cappai R. Amyloid Precursor Protein Dimerisation Reduces Neurite Outgrowth. Mol Neurobiol 2018; 56:13-28. [PMID: 29675574 DOI: 10.1007/s12035-018-1070-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 04/09/2018] [Indexed: 02/08/2023]
Abstract
The amyloid precursor protein (APP) undergoes extensive metabolism, and its transport and proteolytic processing can be modulated by its ability to form a homodimer. We have investigated the functional consequences of stabilised APP dimer expression in cells by studying the engineered dimerisation of the APPL17C (residue 17 in Aβ sequence) construct, which is associated with a 30% increase in APP dimer expression, on APP's neurite outgrowth promoting activity. Overexpression of APPL17C in SH-SY5Y cells decreased neurite outgrowth upon retinoic acid differentiation as compared to overexpressing APPWT cells. The APPL17C phenotype was rescued by replacing the APPL17C media with conditioned media from APPWT cells, indicating that the APPL17C mutant is impairing the secretion of a neuritogenic promoting factor. APPL17C had altered transport and was localised in the endoplasmic reticulum. Defining the molecular basis of the APPL17C phenotype showed that RhoA GTPase activity, a negative regulator of neurite outgrowth, was increased in APPL17C cells. RhoA activity was decreased after APPWT conditioned media rescue. Moreover, treatment with the RhoA inhibitor, Y27632, restored a wild-type morphology to the APPL17C cells. Small RNAseq analysis of APPL17C and APPWT cells identified several differentially expressed miRNAs relating to neurite outgrowth. Of these, miR-34a showed the greatest decrease in expression. Lentiviral-mediated overexpression of miR-34a rescued neurite outgrowth in APPL17C cells to APPWT levels and changed RhoA activation. This study has identified a novel link between APP dimerisation and its neuritogenic activity which is mediated by miR-34a expression.
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Affiliation(s)
- Luan Luu
- Department of Pathology, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Giuseppe D Ciccotosto
- Department of Pathology, The University of Melbourne, Melbourne, VIC, 3010, Australia.,Department of Pharmacology & Therapeutics, The University of Melbourne, Melbourne, VIC, 3010, Australia.,Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Laura J Vella
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Lesley Cheng
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Laila C Roisman
- Department of Pathology, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Gerhard Multhaup
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Andrew F Hill
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Lisa-Marie Munter
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Roberto Cappai
- Department of Pathology, The University of Melbourne, Melbourne, VIC, 3010, Australia. .,Department of Pharmacology & Therapeutics, The University of Melbourne, Melbourne, VIC, 3010, Australia.
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13
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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: 27] [Impact Index Per Article: 4.5] [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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14
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De Luca C, Virtuoso A, Maggio N, Papa M. Neuro-Coagulopathy: Blood Coagulation Factors in Central Nervous System Diseases. Int J Mol Sci 2017; 18:E2128. [PMID: 29023416 PMCID: PMC5666810 DOI: 10.3390/ijms18102128] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 09/30/2017] [Accepted: 10/08/2017] [Indexed: 12/30/2022] Open
Abstract
Blood coagulation factors and other proteins, with modulatory effects or modulated by the coagulation cascade have been reported to affect the pathophysiology of the central nervous system (CNS). The protease-activated receptors (PARs) pathway can be considered the central hub of this regulatory network, mainly through thrombin or activated protein C (aPC). These proteins, in fact, showed peculiar properties, being able to interfere with synaptic homeostasis other than coagulation itself. These specific functions modulate neuronal networks, acting both on resident (neurons, astrocytes, and microglia) as well as circulating immune system cells and the extracellular matrix. The pleiotropy of these effects is produced through different receptors, expressed in various cell types, in a dose- and time-dependent pattern. We reviewed how these pathways may be involved in neurodegenerative diseases (amyotrophic lateral sclerosis, Alzheimer's and Parkinson's diseases), multiple sclerosis, ischemic stroke and post-ischemic epilepsy, CNS cancer, addiction, and mental health. These data open up a new path for the potential therapeutic use of the agonist/antagonist of these proteins in the management of several central nervous system diseases.
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Affiliation(s)
- Ciro De Luca
- Laboratory of Neuronal Networks, University of Campania "Luigi Vanvitelli", 80138 Naples, Italy.
| | - Assunta Virtuoso
- Laboratory of Neuronal Networks, University of Campania "Luigi Vanvitelli", 80138 Naples, Italy.
| | - Nicola Maggio
- Department of Neurology, The Chaim Sheba Medical Center, Tel Hashomer, 52621 Ramat Gan, Israel.
- Department of Neurology and Neurosurgery, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, 6997801 Tel Aviv, Israel.
| | - Michele Papa
- Laboratory of Neuronal Networks, University of Campania "Luigi Vanvitelli", 80138 Naples, Italy.
- SYSBIO, Centre of Systems Biology, University of Milano-Bicocca, 20126 Milano, Italy.
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15
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Yan Y, Xu TH, Harikumar KG, Miller LJ, Melcher K, Xu HE. Dimerization of the transmembrane domain of amyloid precursor protein is determined by residues around the γ-secretase cleavage sites. J Biol Chem 2017; 292:15826-15837. [PMID: 28790170 PMCID: PMC5612113 DOI: 10.1074/jbc.m117.789669] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 08/02/2017] [Indexed: 11/06/2022] Open
Abstract
One of the hallmarks of Alzheimer's disease is the formation of extracellular amyloid plaques that consist mainly of abnormally aggregated forms of amyloid β (Aβ) peptides. These peptides are generated by γ-secretase-catalyzed cleavage of a dimeric membrane-bound C-terminal fragment (C99) of the amyloid precursor protein. Although C99 homodimerization has been linked to Aβ production and changes in the aggregation-determining Aβ42/Aβ40 ratio, the motif through which C99 dimerizes has remained controversial. Here, we have used two independent assays to gain insight into C99 homodimerization in the context of the membrane of live cells: bioluminescence resonance energy transfer and Tango membrane protein-protein interaction assays, which were further confirmed by traditional pull-down assays. Our results indicate a four-amino acid region within the C99 transmembrane helix (43TVIV46) as well as its local secondary structure as critical determinants for homodimerization. These four amino acids are also a hot spot of familial Alzheimer's disease-linked mutations that both decrease C99 homodimerization and γ-secretase cleavage and alter the initial cleavage site to increase the Aβ42/40 ratio.
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Affiliation(s)
- Yan Yan
- From the Key Laboratory of Receptor Research, VARI-SIMM Center, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.,the University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China.,the Center for Cancer and Cell Biology, Innovation and Integration Program, Van Andel Research Institute, Grand Rapids, Michigan 49503, and
| | - Ting-Hai Xu
- From the Key Laboratory of Receptor Research, VARI-SIMM Center, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.,the University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China.,the Center for Cancer and Cell Biology, Innovation and Integration Program, Van Andel Research Institute, Grand Rapids, Michigan 49503, and
| | - Kaleeckal G Harikumar
- the Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona 85259
| | - Laurence J Miller
- the Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona 85259
| | - Karsten Melcher
- the Center for Cancer and Cell Biology, Innovation and Integration Program, Van Andel Research Institute, Grand Rapids, Michigan 49503, and
| | - H Eric Xu
- From the Key Laboratory of Receptor Research, VARI-SIMM Center, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China, .,the Center for Cancer and Cell Biology, Innovation and Integration Program, Van Andel Research Institute, Grand Rapids, Michigan 49503, and
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16
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Herr UM, Strecker P, Storck SE, Thomas C, Rabiej V, Junker A, Schilling S, Schmidt N, Dowds CM, Eggert S, Pietrzik CU, Kins S. LRP1 Modulates APP Intraneuronal Transport and Processing in Its Monomeric and Dimeric State. Front Mol Neurosci 2017; 10:118. [PMID: 28496400 PMCID: PMC5406469 DOI: 10.3389/fnmol.2017.00118] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Accepted: 04/10/2017] [Indexed: 12/31/2022] Open
Abstract
The low-density lipoprotein receptor-related protein 1, LRP1, interacts with APP and affects its processing. This is assumed to be mostly caused by the impact of LRP1 on APP endocytosis. More recently, also an interaction of APP and LRP1 early in the secretory pathway was reported whereat retention of LRP1 in the ER leads to decreased APP cell surface levels and in turn, to reduced Aβ secretion. Here, we extended the biochemical and immunocytochemical analyses by showing via live cell imaging analyses in primary neurons that LRP1 and APP are transported only partly in common (one third) but to a higher degree in distinct fast axonal transport vesicles. Interestingly, co-expression of LRP1 and APP caused a change of APP transport velocities, indicating that LRP1 recruits APP to a specific type of fast axonal transport vesicles. In contrast lowered levels of LRP1 facilitated APP transport. We further show that monomeric and dimeric APP exhibit similar transport characteristics and that both are affected by LRP1 in a similar way, by slowing down APP anterograde transport and increasing its endocytosis rate. In line with this, a knockout of LRP1 in CHO cells and in primary neurons caused an increase of monomeric and dimeric APP surface localization and in turn accelerated shedding by meprin β and ADAM10. Notably, a choroid plexus specific LRP1 knockout caused a much higher secretion of sAPP dimers into the cerebrospinal fluid compared to sAPP monomers. Together, our data show that LRP1 functions as a sorting receptor for APP, regulating its cell surface localization and thereby its processing by ADAM10 and meprin β, with the latter exhibiting a preference for APP in its dimeric state.
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Affiliation(s)
- Uta-Mareike Herr
- Institute of Pathobiochemistry, Molecular Neurodegeneration, University Medical Center of the Johannes Gutenberg-University MainzMainz, Germany
| | - Paul Strecker
- Division of Human Biology and Human Genetics, Technical University of KaiserslauternKaiserslautern, Germany
| | - Steffen E Storck
- Institute of Pathobiochemistry, Molecular Neurodegeneration, University Medical Center of the Johannes Gutenberg-University MainzMainz, Germany
| | - Carolin Thomas
- Division of Human Biology and Human Genetics, Technical University of KaiserslauternKaiserslautern, Germany
| | - Verena Rabiej
- Institute of Pathobiochemistry, Molecular Neurodegeneration, University Medical Center of the Johannes Gutenberg-University MainzMainz, Germany
| | - Anne Junker
- Institute of Pathobiochemistry, Molecular Neurodegeneration, University Medical Center of the Johannes Gutenberg-University MainzMainz, Germany
| | - Sandra Schilling
- Division of Human Biology and Human Genetics, Technical University of KaiserslauternKaiserslautern, Germany
| | - Nadine Schmidt
- Division of Human Biology and Human Genetics, Technical University of KaiserslauternKaiserslautern, Germany
| | - C Marie Dowds
- Division of Human Biology and Human Genetics, Technical University of KaiserslauternKaiserslautern, Germany
| | - Simone Eggert
- Division of Human Biology and Human Genetics, Technical University of KaiserslauternKaiserslautern, Germany
| | - Claus U Pietrzik
- Institute of Pathobiochemistry, Molecular Neurodegeneration, University Medical Center of the Johannes Gutenberg-University MainzMainz, Germany
| | - Stefan Kins
- Division of Human Biology and Human Genetics, Technical University of KaiserslauternKaiserslautern, Germany
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17
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Fragkouli A, Koukouraki P, Vlachos IS, Paraskevopoulou MD, Hatzigeorgiou AG, Doxakis E. Neuronal ELAVL proteins utilize AUF-1 as a co-partner to induce neuron-specific alternative splicing of APP. Sci Rep 2017; 7:44507. [PMID: 28291226 PMCID: PMC5349543 DOI: 10.1038/srep44507] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 02/08/2017] [Indexed: 12/18/2022] Open
Abstract
Aβ peptide that accumulates in Alzheimer’s disease brain, derives from proteolytic processing of the amyloid precursor protein (APP) that exists in three main isoforms derived by alternative splicing. The isoform APP695, lacking exons 7 and 8, is predominately expressed in neurons and abnormal neuronal splicing of APP has been observed in the brain of patients with Alzheimer’s disease. Herein, we demonstrate that expression of the neuronal members of the ELAVL protein family (nELAVLs) correlate with APP695 levels in vitro and in vivo. Moreover, we provide evidence that nELAVLs regulate the production of APP695; by using a series of reporters we show that concurrent binding of nELAVLs to sequences located both upstream and downstream of exon 7 is required for its skipping, whereas nELAVL-binding to a highly conserved U-rich sequence upstream of exon 8, is sufficient for its exclusion. Finally, we report that nELAVLs block APP exon 7 or 8 definition by reducing the binding of the essential splicing factor U2AF65, an effect facilitated by the concurrent binding of AUF-1. Our study provides new insights into the regulation of APP pre-mRNA processing, supports the role for nELAVLs as neuron-specific splicing regulators and reveals a novel function of AUF1 in alternative splicing.
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Affiliation(s)
- Apostolia Fragkouli
- Center for Basic Research, Biomedical Research Foundation Academy of Athens, 4 Soranou Efesiou str, 11527, Athens Greece
| | - Pelagia Koukouraki
- Center for Basic Research, Biomedical Research Foundation Academy of Athens, 4 Soranou Efesiou str, 11527, Athens Greece
| | - Ioannis S Vlachos
- Hellenic Pasteur Institute, 127 Vasilissis Sofias Avenue, 11521 Athens, Greece.,DIANA-Lab, Department of Electrical &Computer Engineering, University of Thessaly, 38221 Volos, Greece
| | - Maria D Paraskevopoulou
- Hellenic Pasteur Institute, 127 Vasilissis Sofias Avenue, 11521 Athens, Greece.,DIANA-Lab, Department of Electrical &Computer Engineering, University of Thessaly, 38221 Volos, Greece
| | - Artemis G Hatzigeorgiou
- Hellenic Pasteur Institute, 127 Vasilissis Sofias Avenue, 11521 Athens, Greece.,DIANA-Lab, Department of Electrical &Computer Engineering, University of Thessaly, 38221 Volos, Greece
| | - Epaminondas Doxakis
- Center for Basic Research, Biomedical Research Foundation Academy of Athens, 4 Soranou Efesiou str, 11527, Athens Greece
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18
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Bhattacharyya R, Fenn RH, Barren C, Tanzi RE, Kovacs DM. Palmitoylated APP Forms Dimers, Cleaved by BACE1. PLoS One 2016; 11:e0166400. [PMID: 27875558 PMCID: PMC5119739 DOI: 10.1371/journal.pone.0166400] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 10/30/2016] [Indexed: 11/26/2022] Open
Abstract
A major rate-limiting step for Aβ generation and deposition in Alzheimer's disease brains is BACE1-mediated cleavage (β-cleavage) of the amyloid precursor protein (APP). We previously reported that APP undergoes palmitoylation at two cysteine residues (Cys186 and Cys187) in the E1-ectodomain. 8-10% of total APP is palmitoylated in vitro and in vivo. Palmitoylated APP (palAPP) shows greater preference for β-cleavage than total APP in detergent resistant lipid rafts. Protein palmitoylation is known to promote protein dimerization. Since dimerization of APP at its E1-ectodomain results in elevated BACE1-mediated cleavage of APP, we have now investigated whether palmitoylation of APP affects its dimerization and whether this leads to elevated β-cleavage of the protein. Here we report that over 90% of palAPP is dimerized while only ~20% of total APP forms dimers. PalAPP-dimers are predominantly cis-oriented while total APP dimerizes in both cis- and trans-orientation. PalAPP forms dimers 4.5-times more efficiently than total APP. Overexpression of the palmitoylating enzymes DHHC7 and DHHC21 that increase palAPP levels and Aβ release, also increased APP dimerization in cells. Conversely, inhibition of APP palmitoylation by pharmacological inhibitors reduced APP-dimerization in coimmunoprecipitation and FLIM/FRET assays. Finally, in vitro BACE1-activity assays demonstrate that palmitoylation-dependent dimerization of APP promotes β-cleavage of APP in lipid-rich detergent resistant cell membranes (DRMs), when compared to total APP. Most importantly, generation of sAPPβ-sAPPβ dimers is dependent on APP-palmitoylation while total sAPPβ generation is not. Since BACE1 shows preference for palAPP dimers over total APP, palAPP dimers may serve as novel targets for effective β-cleavage inhibitors of APP as opposed to BACE1 inhibitors.
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Affiliation(s)
- Raja Bhattacharyya
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Diseases (MIND), Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States of America
| | - Rebecca H. Fenn
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Diseases (MIND), Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States of America
| | - Cory Barren
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Diseases (MIND), Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States of America
| | - Rudolph E. Tanzi
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Diseases (MIND), Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States of America
| | - Dora M. Kovacs
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Diseases (MIND), Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States of America
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19
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Decock M, Stanga S, Octave JN, Dewachter I, Smith SO, Constantinescu SN, Kienlen-Campard P. Glycines from the APP GXXXG/GXXXA Transmembrane Motifs Promote Formation of Pathogenic Aβ Oligomers in Cells. Front Aging Neurosci 2016; 8:107. [PMID: 27242518 PMCID: PMC4861705 DOI: 10.3389/fnagi.2016.00107] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 04/25/2016] [Indexed: 12/31/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common neurodegenerative disorder characterized by progressive cognitive decline leading to dementia. The amyloid precursor protein (APP) is a ubiquitous type I transmembrane (TM) protein sequentially processed to generate the β-amyloid peptide (Aβ), the major constituent of senile plaques that are typical AD lesions. There is a growing body of evidence that soluble Aβ oligomers correlate with clinical symptoms associated with the disease. The Aβ sequence begins in the extracellular juxtamembrane region of APP and includes roughly half of the TM domain. This region contains GXXXG and GXXXA motifs, which are critical for both TM protein interactions and fibrillogenic properties of peptides derived from TM α-helices. Glycine-to-leucine mutations of these motifs were previously shown to affect APP processing and Aβ production in cells. However, the detailed contribution of these motifs to APP dimerization, their relation to processing, and the conformational changes they can induce within Aβ species remains undefined. Here, we describe highly resistant Aβ42 oligomers that are produced in cellular membrane compartments. They are formed in cells by processing of the APP amyloidogenic C-terminal fragment (C99), or by direct expression of a peptide corresponding to Aβ42, but not to Aβ40. By a point-mutation approach, we demonstrate that glycine-to-leucine mutations in the G29XXXG33 and G38XXXA42 motifs dramatically affect the Aβ oligomerization process. G33 and G38 in these motifs are specifically involved in Aβ oligomerization; the G33L mutation strongly promotes oligomerization, while G38L blocks it with a dominant effect on G33 residue modification. Finally, we report that the secreted Aβ42 oligomers display pathological properties consistent with their suggested role in AD, but do not induce toxicity in survival assays with neuronal cells. Exposure of neurons to these Aβ42 oligomers dramatically affects neuronal differentiation and, consequently, neuronal network maturation.
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Affiliation(s)
- Marie Decock
- CEMO-Alzheimer Dementia, Institute of Neuroscience, Université Catholique de Louvain Brussels, Belgium
| | - Serena Stanga
- CEMO-Alzheimer Dementia, Institute of Neuroscience, Université Catholique de Louvain Brussels, Belgium
| | - Jean-Noël Octave
- CEMO-Alzheimer Dementia, Institute of Neuroscience, Université Catholique de Louvain Brussels, Belgium
| | - Ilse Dewachter
- CEMO-Alzheimer Dementia, Institute of Neuroscience, Université Catholique de Louvain Brussels, Belgium
| | - Steven O Smith
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook NY, USA
| | - Stefan N Constantinescu
- Ludwig Institute for Cancer Research - de Duve Institute, Université Catholique de Louvain Brussels, Belgium
| | - Pascal Kienlen-Campard
- CEMO-Alzheimer Dementia, Institute of Neuroscience, Université Catholique de Louvain Brussels, Belgium
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20
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Scheckel C, Drapeau E, Frias MA, Park CY, Fak J, Zucker-Scharff I, Kou Y, Haroutunian V, Ma'ayan A, Buxbaum JD, Darnell RB. Regulatory consequences of neuronal ELAV-like protein binding to coding and non-coding RNAs in human brain. eLife 2016; 5. [PMID: 26894958 PMCID: PMC4798961 DOI: 10.7554/elife.10421] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 12/19/2015] [Indexed: 12/12/2022] Open
Abstract
Neuronal ELAV-like (nELAVL) RNA binding proteins have been linked to numerous neurological disorders. We performed crosslinking-immunoprecipitation and RNAseq on human brain, and identified nELAVL binding sites on 8681 transcripts. Using knockout mice and RNAi in human neuroblastoma cells, we showed that nELAVL intronic and 3' UTR binding regulates human RNA splicing and abundance. We validated hundreds of nELAVL targets among which were important neuronal and disease-associated transcripts, including Alzheimer's disease (AD) transcripts. We therefore investigated RNA regulation in AD brain, and observed differential splicing of 150 transcripts, which in some cases correlated with differential nELAVL binding. Unexpectedly, the most significant change of nELAVL binding was evident on non-coding Y RNAs. nELAVL/Y RNA complexes were specifically remodeled in AD and after acute UV stress in neuroblastoma cells. We propose that the increased nELAVL/Y RNA association during stress may lead to nELAVL sequestration, redistribution of nELAVL target binding, and altered neuronal RNA splicing. DOI:http://dx.doi.org/10.7554/eLife.10421.001 When a gene is active, its DNA is copied into a molecule of RNA. This molecule then undergoes a process called splicing which removes certain segments, and the resulting ‘messenger RNA’ molecule is then translated into protein. Many messenger RNAs go through alternative splicing, whereby different segments can be included or excluded from the final molecule. This allows more than one type of protein to be produced from a single gene. Specialized RNA binding proteins associate with messenger RNAs and regulate not only their splicing, but also their abundance and location within the cell. These activities are crucially important in the brain where forming memories and learning new skills requires thousands of proteins to be made rapidly. Many members of a family of RNA binding proteins called ELAV-like proteins are unique to neurons. These proteins have also been associated with conditions such as Alzheimer’s disease, but it was not known which messenger RNAs were the targets of these proteins in the human brain. Scheckel, Drapeau et al. have now addressed this question and used a method termed 'CLIP' to identify thousands of messenger RNAs that directly bind to neuronal ELAV-like proteins in the human brain. Many of these messenger RNAs coded for proteins that are important for the health of neurons, and neuronal ELAV-like proteins were shown to regulate both the alternative splicing and the abundance of these messenger RNAs. The regulation of RNA molecules in post-mortem brain samples of people with or without Alzheimer’s disease was then compared. Scheckel, Drapeau et al. unexpectedly observed that, in the Alzheimer’s disease patients, the neuronal ELAV-like proteins were very often associated with a class of RNA molecules known as Y RNAs. These RNA molecules do not code for proteins, and are therefore classified as non-coding RNA. Moreover, massive shifts in the binding of ELAV-like proteins onto Y RNAs were observed in neurons grown in the laboratory that had been briefly stressed by exposure to ultraviolet radiation. Scheckel, Drapeau et al. suggest that the strong tendency of neuronal ELAV-like proteins to bind to Y RNAs in conditions of short- or long-term stress, including Alzheimer’s disease, might prevent these proteins from associating with their normal messenger RNA targets. This was supported by finding that some messenger RNAs targeted by neuronal ELAV-like proteins showed altered regulation after stress. Such changes to the normal regulation of these messenger RNAs could have a large impact on the proteins that are produced from them. Together, these findings link Y RNAs to both neuronal stress and Alzheimer’s disease, and suggest a new way that a cell can alter which messenger RNAs are expressed in response to changes in its environment. The next step is to explore what causes the shift in neuronal ELAV-like protein binding from messenger RNAs to Y RNAs and how it might contribute to disease. DOI:http://dx.doi.org/10.7554/eLife.10421.002
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Affiliation(s)
- Claudia Scheckel
- Laboratory of Molecular Neuro-Oncology, The Rockefeller University, New York, United States.,Howard Hughes Medical Institute, The Rockefeller University, New York, United States
| | - Elodie Drapeau
- Seaver Autism Center for Research and Treatment, New York, United States.,Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Maria A Frias
- Laboratory of Molecular Neuro-Oncology, The Rockefeller University, New York, United States.,Howard Hughes Medical Institute, The Rockefeller University, New York, United States
| | - Christopher Y Park
- Laboratory of Molecular Neuro-Oncology, The Rockefeller University, New York, United States.,Howard Hughes Medical Institute, The Rockefeller University, New York, United States.,New York Genome Center, New York, United States
| | - John Fak
- Laboratory of Molecular Neuro-Oncology, The Rockefeller University, New York, United States.,Howard Hughes Medical Institute, The Rockefeller University, New York, United States
| | - Ilana Zucker-Scharff
- Laboratory of Molecular Neuro-Oncology, The Rockefeller University, New York, United States.,Howard Hughes Medical Institute, The Rockefeller University, New York, United States
| | - Yan Kou
- Seaver Autism Center for Research and Treatment, New York, United States.,Department of Pharmacology and Systems Therapeutics, BD2K-LINCS Data Integration and Coordination Center, Mount Sinai Knowledge Management Center for Illuminating the Druggable Genome, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Vahram Haroutunian
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, United States.,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, United States.,James J. Peters VA Medical Center, New York, United States
| | - Avi Ma'ayan
- Department of Pharmacology and Systems Therapeutics, BD2K-LINCS Data Integration and Coordination Center, Mount Sinai Knowledge Management Center for Illuminating the Druggable Genome, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Joseph D Buxbaum
- Seaver Autism Center for Research and Treatment, New York, United States.,Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, United States.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, United States.,Mindich Child Health Institute, Icahn School of Medicine at Mount Sinai, New York, United States.,Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Robert B Darnell
- Laboratory of Molecular Neuro-Oncology, The Rockefeller University, New York, United States.,Howard Hughes Medical Institute, The Rockefeller University, New York, United States.,New York Genome Center, New York, United States
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21
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Stanga S, Zanou N, Audouard E, Tasiaux B, Contino S, Vandermeulen G, René F, Loeffler JP, Clotman F, Gailly P, Dewachter I, Octave JN, Kienlen-Campard P. APP-dependent glial cell line-derived neurotrophic factor gene expression drives neuromuscular junction formation. FASEB J 2015; 30:1696-711. [PMID: 26718890 DOI: 10.1096/fj.15-278739] [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: 07/09/2015] [Accepted: 12/08/2015] [Indexed: 12/13/2022]
Abstract
Besides its crucial role in the pathogenesis of Alzheimer's disease, the knowledge of amyloid precursor protein (APP) physiologic functions remains surprisingly scarce. Here, we show that APP regulates the transcription of the glial cell line-derived neurotrophic factor (GDNF). APP-dependent regulation of GDNF expression affects muscle strength, muscular trophy, and both neuronal and muscular differentiation fundamental for neuromuscular junction (NMJ) maturation in vivo In a nerve-muscle coculture model set up to modelize NMJ formation in vitro, silencing of muscular APP induces a 30% decrease in secreted GDNF levels and a 40% decrease in the total number of NMJs together with a significant reduction in the density of acetylcholine vesicles at the presynaptic site and in neuronal maturation. These defects are rescued by GDNF expression in muscle cells in the conditions where muscular APP has been previously silenced. Expression of GDNF in muscles of amyloid precursor protein null mice corrected the aberrant synaptic morphology of NMJs. Our findings highlight for the first time that APP-dependent GDNF expression drives the process of NMJ formation, providing new insights into the link between APP gene regulatory network and physiologic functions.-Stanga, S., Zanou, N., Audouard, E., Tasiaux, B., Contino, S., Vandermeulen, G., René, F., Loeffler, J.-P., Clotman, F., Gailly, P., Dewachter, I., Octave, J.-N., Kienlen-Campard, P. APP-dependent glial cell line-derived neurotrophic factor gene expression drives neuromuscular junction formation.
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Affiliation(s)
- Serena Stanga
- Alzheimer Research Group, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Nadège Zanou
- Laboratory of Cell Physiology, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Emilie Audouard
- Laboratory of Neural Differentiation, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Bernadette Tasiaux
- Alzheimer Research Group, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Sabrina Contino
- Alzheimer Research Group, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Gaëlle Vandermeulen
- Advanced Drug Delivery and Biomaterials, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium; and
| | - Frédérique René
- Institut National de la Santé et de la Recherche Médicale, Unité 1118 Mécanismes Centraux et Périphériques de la Neurodégénérescence, Université de Strasbourg, Strasbourg Cedex, France
| | - Jean-Philippe Loeffler
- Institut National de la Santé et de la Recherche Médicale, Unité 1118 Mécanismes Centraux et Périphériques de la Neurodégénérescence, Université de Strasbourg, Strasbourg Cedex, France
| | - Frédéric Clotman
- Laboratory of Neural Differentiation, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Philippe Gailly
- Laboratory of Cell Physiology, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Ilse Dewachter
- Alzheimer Research Group, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Jean-Noël Octave
- Alzheimer Research Group, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Pascal Kienlen-Campard
- Alzheimer Research Group, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium;
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22
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Sun X, Chen WD, Wang YD. β-Amyloid: the key peptide in the pathogenesis of Alzheimer's disease. Front Pharmacol 2015; 6:221. [PMID: 26483691 PMCID: PMC4588032 DOI: 10.3389/fphar.2015.00221] [Citation(s) in RCA: 187] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 09/17/2015] [Indexed: 12/20/2022] Open
Abstract
The amyloid β peptide (Aβ) is a critical initiator that triggers the progression of Alzheimer's Disease (AD) via accumulation and aggregation, of which the process may be caused by Aβ overproduction or perturbation clearance. Aβ is generated from amyloid precursor protein through sequential cleavage of β- and γ-secretases while Aβ removal is dependent on the proteolysis and lysosome degradation system. Here, we overviewed the biogenesis and toxicity of Aβ as well as the regulation of Aβ production and clearance. Moreover, we also summarized the animal models correlated with Aβ that are essential in AD research. In addition, we discussed current immunotherapeutic approaches targeting Aβ to give some clues for exploring the more potentially efficient drugs for treatment of AD.
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Affiliation(s)
- Xiaojuan Sun
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Medicine, Henan University Kaifeng, China
| | - Wei-Dong Chen
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Medicine, Henan University Kaifeng, China
| | - Yan-Dong Wang
- State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology Beijing, China
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23
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Decock M, El Haylani L, Stanga S, Dewachter I, Octave JN, Smith SO, Constantinescu SN, Kienlen-Campard P. Analysis by a highly sensitive split luciferase assay of the regions involved in APP dimerization and its impact on processing. FEBS Open Bio 2015; 5:763-73. [PMID: 26500837 PMCID: PMC4588712 DOI: 10.1016/j.fob.2015.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 08/07/2015] [Accepted: 09/01/2015] [Indexed: 12/27/2022] Open
Abstract
Amyloid precursor protein (APP) dimerizes more than its C-terminal fragments in cells. Mutations of membrane GXXXG motifs affect Aβ production but not APP dimerization. Deletion of the APP intracellular domain increases APP dimerization.
Alzheimer’s disease (AD) is a neurodegenerative disease that causes progressive loss of cognitive functions, leading to dementia. Two types of lesions are found in AD brains: neurofibrillary tangles and senile plaques. The latter are composed mainly of the β-amyloid peptide (Aβ) generated by amyloidogenic processing of the amyloid precursor protein (APP). Several studies have suggested that dimerization of APP is closely linked to Aβ production. Nevertheless, the mechanisms controlling APP dimerization and their role in APP function are not known. Here we used a new luciferase complementation assay to analyze APP dimerization and unravel the involvement of its three major domains: the ectodomain, the transmembrane domain and the intracellular domain. Our results indicate that within cells full-length APP dimerizes more than its α and β C-terminal fragments, confirming the pivotal role of the ectodomain in this process. Dimerization of the APP transmembrane (TM) domain has been reported to regulate processing at the γ-cleavage site. We show that both non-familial and familial AD mutations in the TM GXXXG motifs strongly modulate Aβ production, but do not consistently change dimerization of the C-terminal fragments. Finally, we found for the first time that removal of intracellular domain strongly increases APP dimerization. Increased APP dimerization is linked to increased non-amyloidogenic processing.
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Key Words
- AD, Alzheimer’s disease
- AICD, APP intracellular domain
- APP
- APP, amyloid precursor protein
- Alzheimer disease
- Amyloid beta peptide
- Aβ, β-amyloid peptide
- CHO, chinese hamster ovary
- CTF, C-terminal fragment
- DAPT, N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester
- DTT, dithiothreitol
- Dimerization
- ECL, enzymatic chemi-luminescence
- ECLIA, electro-chemiluminescence immuno-assay
- FBS, fetal bovine serum
- FRET, fluorescence resonance energy transfer
- GXXXG motifs
- KPI, Kunitz-type protease inhibitor
- NSAIDs, nonsteroidal anti-inflammatory drugs
- PBS, phosphate buffered saline
- PS1/PS2, presenilin1/presenilin2
- RLU, relative light unit
- SP, signal peptide
- Split luciferase
- TM, transmembrane
- YFP, yellow fluorescent protein
- sAPPα, soluble APPα
- sAPPβ, soluble APPβ
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Affiliation(s)
- Marie Decock
- Institute of Neuroscience, Université catholique de Louvain, Brussels 1200, Belgium
| | - Laetitia El Haylani
- Institute of Neuroscience, Université catholique de Louvain, Brussels 1200, Belgium
| | - Serena Stanga
- Institute of Neuroscience, Université catholique de Louvain, Brussels 1200, Belgium
| | - Ilse Dewachter
- Institute of Neuroscience, Université catholique de Louvain, Brussels 1200, Belgium
| | - Jean-Noël Octave
- Institute of Neuroscience, Université catholique de Louvain, Brussels 1200, Belgium
| | - Steven O Smith
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA
| | - Stefan N Constantinescu
- de Duve Institute and Ludwig Institute for Cancer Research, Université catholique de Louvain, Brussels 1200, Belgium
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24
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Su M, Chang W, Wang D, Cui M, Lin Y, Wu S, Xu T. Expression and activity analysis of a new fusion protein targeting ovarian cancer cells. Oncol Rep 2015; 34:1337-44. [PMID: 26166362 DOI: 10.3892/or.2015.4118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 06/15/2015] [Indexed: 11/06/2022] Open
Abstract
The aim of the present study was to develop a new therapeutic drug to improve the prognosis of ovarian cancer patients. Human urokinase-type plasminogen activator (uPA)17-34-kunitz-type protease inhibitor (KPI) eukaryotic expression vector was constructed and recombinant human uPA17-34-KPI (rhuPA17-34-KPI) in P. pastoris was expressed. In the present study, the DNA sequences that encode uPA 17-34 amino acids were created according to the native amino acids sequence and inserted into the KPI-pPICZαC vector, which was constructed. Then, uPA17‑34-KPI-pPICZαC was transformed into P. pastoris X-33, and rhuPA17-34-KPI was expressed by induction of methanol. The bioactivities of a recombinant fusion protein were detected with trypsin inhibition analysis, and the inhibitory effects on the growth of ovarian cancer cells were identified using the TUNEL assay, in vitro wound‑healing assay and Matrigel model analysis. The results of the DNA sequence analysis of the recombinant vector uPA17-34-KPI‑pPICZα demonstrated that the DNA‑encoding human uPA 17-34 amino acids, 285-288 amino acids of amyloid precursor protein (APP) and 1-57 amino acids of KPI were correctly inserted into the pPICZαC vector. Following induction by methonal, the fusion protein with a molecular weight of 8.8 kDa was observed using SDS-PAGE and western blot analysis. RhuPA17-34-KPI was expressed in P. pastoris with a yield of 50 mg/l in a 50-ml tube. The recombinant fusion protein was able to inhibit the activity of trypsin, inhibit growth and induce apoptosis of SKOV3 cells, and inhibit the invasion and metastasis of ovarian cancer cells. By considering uPA17-34 amino acid specific binding uPAR as the targeted part of fusion protein and utilizing the serine protease inhibitor activity of KPI, it was found that the recombinant fusion protein uPA17-34-KPI inhibited the invasion and metastasis of ovarian tumors, and may therefore be regarded as effective in targeted treatment.
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Affiliation(s)
- Manman Su
- Department of Obstetrics and Gynecology, The Second Hospital, Jilin University, Changchun, Jilin, P.R. China
| | - Weiqin Chang
- Department of Obstetrics and Gynecology, The Second Hospital, Jilin University, Changchun, Jilin, P.R. China
| | - Dingding Wang
- Department of Biotechnology, College of Life Sciences and Biopharmacology, Guangdong Pharmaceutical University, Guangzhou, Guangdong, P.R. China
| | - Manhua Cui
- Department of Obstetrics and Gynecology, The Second Hospital, Jilin University, Changchun, Jilin, P.R. China
| | - Yang Lin
- Department of Obstetrics and Gynecology, The Second Hospital, Jilin University, Changchun, Jilin, P.R. China
| | - Shuying Wu
- Department of Obstetrics and Gynecology, The Second Hospital, Jilin University, Changchun, Jilin, P.R. China
| | - Tianmin Xu
- Department of Obstetrics and Gynecology, The Second Hospital, Jilin University, Changchun, Jilin, P.R. China
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25
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Marinangeli C, Tasiaux B, Opsomer R, Hage S, Sodero AO, Dewachter I, Octave JN, Smith SO, Constantinescu SN, Kienlen-Campard P. Presenilin transmembrane domain 8 conserved AXXXAXXXG motifs are required for the activity of the γ-secretase complex. J Biol Chem 2015; 290:7169-84. [PMID: 25614624 DOI: 10.1074/jbc.m114.601286] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Understanding the molecular mechanisms controlling the physiological and pathological activity of γ-secretase represents a challenging task in Alzheimer disease research. The assembly and proteolytic activity of this enzyme require the correct interaction of the 19 transmembrane domains (TMDs) present in its four subunits, including presenilin (PS1 or PS2), the γ-secretase catalytic core. GXXXG and GXXXG-like motifs are critical for TMDs interactions as well as for protein folding and assembly. The GXXXG motifs on γ-secretase subunits (e.g. APH-1) or on γ-secretase substrates (e.g. APP) are known to be involved in γ-secretase assembly and in Aβ peptide production, respectively. We identified on PS1 and PS2 TMD8 two highly conserved AXXXAXXXG motifs. The presence of a mutation causing an inherited form of Alzheimer disease (familial Alzheimer disease) in the PS1 motif suggested their involvement in the physiopathological configuration of the γ-secretase complex. In this study, we targeted the role of these motifs on TMD8 of PSs, focusing on their role in PS assembly and catalytic activity. Each motif was mutated, and the impact on complex assembly, activity, and substrate docking was monitored. Different amino acid substitutions on the same motif resulted in opposite effects on γ-secretase activity, without affecting the assembly or significantly impairing the maturation of the complex. Our data suggest that AXXXAXXXG motifs in PS TMD8 are key determinants for the conformation of the mature γ-secretase complex, participating in the switch between the physiological and pathological functional conformations of the γ-secretase.
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Affiliation(s)
| | | | | | - Salim Hage
- the Louvain Drug Research Institute, and
| | | | | | | | - Steven O Smith
- the Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794-5215
| | - Stefan N Constantinescu
- the de Duve Institute and Ludwig Institute for Cancer Research, Université Catholique de Louvain, Brussels 1200, Belgium and
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26
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Lin YC, Wang JY, Wang KC, Liao JY, Cheng IH. Differential regulation of amyloid precursor protein sorting with pathological mutations results in a distinct effect on amyloid-β production. J Neurochem 2014; 131:407-12. [PMID: 25053581 DOI: 10.1111/jnc.12829] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 07/07/2014] [Accepted: 07/08/2014] [Indexed: 12/31/2022]
Abstract
The deposition of amyloid-β (Aβ) peptide, which is generated from amyloid precursor protein (APP), is the pathological hallmark of Alzheimer's disease (AD). Three APP familial AD mutations (D678H, D678N, and H677R) located at the sixth and seventh amino acid of Aβ have distinct effect on Aβ aggregation, but their influence on the physiological and pathological roles of APP remain unclear. We found that the D678H mutation strongly enhances amyloidogenic cleavage of APP, thus increasing the production of Aβ. This enhancement of amyloidogenic cleavage is likely because of the acceleration of APPD678H sorting into the endosomal-lysosomal pathway. In contrast, the APPD678N and APPH677R mutants do not cause the same effects. Therefore, this study indicates a regulatory role of D678H in APP sorting and processing, and provides genetic evidence for the importance of APP sorting in AD pathogenesis. The internalization of amyloid precursor protein (APP) increases its opportunity to be processed by β-secretase and to produce Amyloid-β (Aβ) that causes Alzheimer's disease (AD). We report a pathogenic APPD678H mutant that enhances APP internalization into the endosomal-lysosomal pathway and thus promotes the β-secretase cleavage and Aβ production. This study provides genetic evidence for the importance of APP sorting in AD pathogenesis.
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Affiliation(s)
- Yen-Chen Lin
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan; Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
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27
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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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28
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Jiang S, Li Y, Zhang X, Bu G, Xu H, Zhang YW. Trafficking regulation of proteins in Alzheimer's disease. Mol Neurodegener 2014; 9:6. [PMID: 24410826 PMCID: PMC3891995 DOI: 10.1186/1750-1326-9-6] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 12/15/2013] [Indexed: 12/12/2022] Open
Abstract
The β-amyloid (Aβ) peptide has been postulated to be a key determinant in the pathogenesis of Alzheimer’s disease (AD). Aβ is produced through sequential cleavage of the β-amyloid precursor protein (APP) by β- and γ-secretases. APP and relevant secretases are transmembrane proteins and traffic through the secretory pathway in a highly regulated fashion. Perturbation of their intracellular trafficking may affect dynamic interactions among these proteins, thus altering Aβ generation and accelerating disease pathogenesis. Herein, we review recent progress elucidating the regulation of intracellular trafficking of these essential protein components in AD.
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Affiliation(s)
| | | | | | | | | | - Yun-wu Zhang
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian 361102, China.
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Visualization and quantification of APP intracellular domain-mediated nuclear signaling by bimolecular fluorescence complementation. PLoS One 2013; 8:e76094. [PMID: 24086696 PMCID: PMC3783399 DOI: 10.1371/journal.pone.0076094] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 08/21/2013] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND The amyloid precursor protein (APP) intracellular domain (AICD) is released from full-length APP upon sequential cleavage by either α- or β-secretase followed by γ-secretase. Together with the adaptor protein Fe65 and the histone acetyltransferase Tip60, AICD forms nuclear multiprotein complexes (AFT complexes) that function in transcriptional regulation. OBJECTIVE To develop a medium-throughput machine-based assay for visualization and quantification of AFT complex formation in cultured cells. METHODS We used cotransfection of bimolecular fluorescence complementation (BiFC) fusion constructs of APP and Tip60 for analysis of subcellular localization by confocal microscopy and quantification by flow cytometry (FC). RESULTS Our novel BiFC-constructs show a nuclear localization of AFT complexes that is identical to conventional fluorescence-tagged constructs. Production of the BiFC signal is dependent on the adaptor protein Fe65 resulting in fluorescence complementation only after Fe65-mediated nuclear translocation of AICD and interaction with Tip60. We applied the AFT-BiFC system to show that the Swedish APP familial Alzheimer's disease mutation increases AFT complex formation, consistent with the notion that AICD mediated nuclear signaling mainly occurs following APP processing through the amyloidogenic β-secretase pathway. Next, we studied the impact of posttranslational modifications of AICD on AFT complex formation. Mutation of tyrosine 682 in the YENPTY motif of AICD to phenylalanine prevents phosphorylation resulting in increased nuclear AFT-BiFC signals. This is consistent with the negative impact of tyrosine phosphorylation on Fe65 binding to AICD. Finally, we studied the effect of oxidative stress. Our data shows that oxidative stress, at a level that also causes cell death, leads to a reduction in AFT-BiFC signals. CONCLUSION We established a new method for visualization and FC quantification of the interaction between AICD, Fe65 and Tip60 in the nucleus based on BiFC. It enables flow cytometric analysis of AICD nuclear signaling and is characterized by scalability and low background fluorescence.
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Shariati SAM, De Strooper B. Redundancy and divergence in the amyloid precursor protein family. FEBS Lett 2013; 587:2036-45. [PMID: 23707420 DOI: 10.1016/j.febslet.2013.05.026] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 05/08/2013] [Indexed: 11/30/2022]
Abstract
Gene duplication provides genetic material required for functional diversification. An interesting example is the amyloid precursor protein (APP) protein family. The APP gene family has experienced both expansion and contraction during evolution. The three mammalian members have been studied quite extensively in combined knock out models. The underlying assumption is that APP, amyloid precursor like protein 1 and 2 (APLP1, APLP2) are functionally redundant. This assumption is primarily supported by the similarities in biochemical processing of APP and APLPs and on the fact that the different APP genes appear to genetically interact at the level of the phenotype in combined knockout mice. However, unique features in each member of the APP family possibly contribute to specification of their function. In the current review, we discuss the evolution and the biology of the APP protein family with special attention to the distinct properties of each homologue. We propose that the functions of APP, APLP1 and APLP2 have diverged after duplication to contribute distinctly to different neuronal events. Our analysis reveals that APLP2 is significantly diverged from APP and APLP1.
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Affiliation(s)
- S Ali M Shariati
- KU Leuven, Center for Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), 3000 Leuven, Belgium
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Nalivaeva NN, Turner AJ. The amyloid precursor protein: a biochemical enigma in brain development, function and disease. FEBS Lett 2013; 587:2046-54. [PMID: 23684647 DOI: 10.1016/j.febslet.2013.05.010] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 05/06/2013] [Accepted: 05/06/2013] [Indexed: 12/11/2022]
Abstract
For 20 years the amyloid cascade hypothesis of Alzheimer disease (AD) has placed the amyloid-β peptide (Aβ), formed from the amyloid precursor protein (APP), centre stage in the process of neurodegeneration. However, no new therapeutic agents have reached the clinic through exploitation of the hypothesis. The APP metabolites, including Aβ, generated by its proteolytic processing, have distinct physiological functions. In particular, the cleaved intracellular domain of APP (AICD) regulates expression of several genes, including APP itself, the β-secretase BACE-1 and the Aβ-degrading enzyme, neprilysin and this transcriptional regulation involves direct promoter binding of AICD. Of the three major splice isoforms of APP (APP695, APP751, APP770), APP695 is the predominant neuronal form, from which Aβ and transcriptionally-active AICD are preferentially generated by selective processing through the amyloidogenic pathway. Despite intensive research, the normal functions of the APP isoforms remain an enigma. APP plays an important role in brain development, memory and synaptic plasticity and secreted forms of APP are neuroprotective. A fuller understanding of the physiological and pathological actions of APP and its metabolic and gene regulatory network could provide new therapeutic opportunities in neurodegeneration, including AD.
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Affiliation(s)
- Natalia N Nalivaeva
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
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Octave JN, Pierrot N, Ferao Santos S, Nalivaeva NN, Turner AJ. From synaptic spines to nuclear signaling: nuclear and synaptic actions of the amyloid precursor protein. J Neurochem 2013; 126:183-90. [DOI: 10.1111/jnc.12239] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Revised: 02/25/2013] [Accepted: 02/26/2013] [Indexed: 10/27/2022]
Affiliation(s)
- Jean-Noël Octave
- Université Catholique de Louvain; Institute of Neuroscience (IoNS); Brussels Belgium
| | - Nathalie Pierrot
- Université Catholique de Louvain; Institute of Neuroscience (IoNS); Brussels Belgium
| | - Susana Ferao Santos
- Université Catholique de Louvain; Institute of Neuroscience (IoNS); Brussels Belgium
| | - Natalia N. Nalivaeva
- School of Molecular and Cellular Biology; Faculty of Biological Sciences; University of Leeds; Leeds UK
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry; RAS; St. Petersburg Russia
| | - Anthony J. Turner
- School of Molecular and Cellular Biology; Faculty of Biological Sciences; University of Leeds; Leeds UK
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Devauges V, Marquer C, Lécart S, Cossec JC, Potier MC, Fort E, Suhling K, Lévêque-Fort S. Homodimerization of amyloid precursor protein at the plasma membrane: a homoFRET study by time-resolved fluorescence anisotropy imaging. PLoS One 2012; 7:e44434. [PMID: 22973448 PMCID: PMC3433432 DOI: 10.1371/journal.pone.0044434] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 08/03/2012] [Indexed: 11/18/2022] Open
Abstract
Classical FRET (Förster Resonance Energy Transfer) using two fluorescent labels (one for the donor and another one for the acceptor) is not efficient for studying the homodimerization of a protein as only half of the homodimers formed can be identified by this technique. We thus resorted to homoFRET detected by time-resolved Fluorescence Anisotropy IMaging (tr-FAIM). To specifically image the plasma membrane of living cells, an original combination of tr-FAIM and Total Internal Reflection Fluorescence Lifetime Imaging Microscope (TIRFLIM) was implemented. The correcting factor accounting for the depolarization due to the high numerical aperture (NA) objective, mandatory for TIRF microscopy, was quantified on fluorescein solutions and on HEK293 cells expressing enhanced Green Fluorescence Protein (eGFP). Homodimerization of Amyloid Precursor Protein (APP), a key mechanism in the etiology of Alzheimer’s disease, was measured on this original set-up. We showed, both in epifluorescence and under TIRF excitation, different energy transfer rates associated with the homodimerization of wild type APP-eGFP or of a mutated APP-eGFP, which forms constitutive dimers. This original set-up thus offers promising prospects for future studies of protein homodimerization in living cells in control and pathological conditions.
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Affiliation(s)
- Viviane Devauges
- Institut des Sciences Moléculaires d’Orsay, CNRS UMR 8214, Univ. Paris Sud, Orsay, France
- Laboratoire Charles Fabry, CNRS UMR 8501, Institut d’Optique, Univ. Paris Sud, Palaiseau, France
- Centre de Photonique Biomédicale, Univ. Paris Sud, CLUPS/LUMAT FR2764, Orsay, France
| | | | - Sandrine Lécart
- Centre de Photonique Biomédicale, Univ. Paris Sud, CLUPS/LUMAT FR2764, Orsay, France
| | | | | | - Emmanuel Fort
- Institut Langevin, ESPCI ParisTech, Univ. Paris Diderot, UMR 7587, Paris, France
| | - Klaus Suhling
- Department of Physics, King’s College London, Strand, London, United Kingdom
| | - Sandrine Lévêque-Fort
- Institut des Sciences Moléculaires d’Orsay, CNRS UMR 8214, Univ. Paris Sud, Orsay, France
- Centre de Photonique Biomédicale, Univ. Paris Sud, CLUPS/LUMAT FR2764, Orsay, France
- * E-mail:
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Claeysen S, Cochet M, Donneger R, Dumuis A, Bockaert J, Giannoni P. Alzheimer culprits: cellular crossroads and interplay. Cell Signal 2012; 24:1831-40. [PMID: 22627093 DOI: 10.1016/j.cellsig.2012.05.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 05/09/2012] [Indexed: 12/22/2022]
Abstract
Alzheimer's disease (AD) is the primary cause of dementia in the elderly and one of the major health problems worldwide. Since its first description by Alois Alzheimer in 1907, noticeable but insufficient scientific comprehension of this complex pathology has been achieved. All the research that has been pursued takes origin from the identification of the pathological hallmarks in the forms of amyloid-β (Aβ) deposits (plaques), and aggregated hyperphosphorylated tau protein filaments (named neurofibrillary tangles). Since this discovery, many hypotheses have been proposed to explain the origin of the pathology. The "amyloid cascade hypothesis" is the most accredited theory. The mechanism suggested to be one of the initial causes of AD is an imbalance between the production and the clearance of Aβ peptides. Therefore, Amyloid Precursor Protein (APP) synthesis, trafficking and metabolism producing either the toxic Aβ peptide via the amyloidogenic pathway or the sAPPα fragment via the non amyloidogenic pathway have become appealing subjects of study. Being able to reduce the formation of the toxic Aβ peptides is obviously an immediate approach in the trial to prevent AD. The following review summarizes the most relevant discoveries in the field of the last decades.
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Affiliation(s)
- Sylvie Claeysen
- CNRS, UMR-5203, Institut de Génomique Fonctionnelle, F-34000 Montpellier, France.
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