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Latina V, Atlante A, Malerba F, La Regina F, Balzamino BO, Micera A, Pignataro A, Stigliano E, Cavallaro S, Calissano P, Amadoro G. The Cleavage-Specific Tau 12A12mAb Exerts an Anti-Amyloidogenic Action by Modulating the Endocytic and Bioenergetic Pathways in Alzheimer's Disease Mouse Model. Int J Mol Sci 2023; 24:ijms24119683. [PMID: 37298634 DOI: 10.3390/ijms24119683] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 05/27/2023] [Accepted: 05/31/2023] [Indexed: 06/12/2023] Open
Abstract
Beyond deficits in hippocampal-dependent episodic memory, Alzheimer's Disease (AD) features sensory impairment in visual cognition consistent with extensive neuropathology in the retina. 12A12 is a monoclonal cleavage specific antibody (mAb) that in vivo selectively neutralizes the AD-relevant, harmful N-terminal 20-22 kDa tau fragment(s) (i.e., NH2htau) without affecting the full-length normal protein. When systemically injected into the Tg2576 mouse model overexpressing a mutant form of Amyloid Precursor Protein (APP), APPK670/671L linked to early onset familial AD, this conformation-specific tau mAb successfully reduces the NH2htau accumulating both in their brain and retina and, thus, markedly alleviates the phenotype-associated signs. By means of a combined biochemical and metabolic experimental approach, we report that 12A12mAb downregulates the steady state expression levels of APP and Beta-Secretase 1 (BACE-1) and, thus, limits the Amyloid beta (Aβ) production both in the hippocampus and retina from this AD animal model. The local, antibody-mediated anti-amyloidogenic action is paralleled in vivo by coordinated modulation of the endocytic (BIN1, RIN3) and bioenergetic (glycolysis and L-Lactate) pathways. These findings indicate for the first time that similar molecular and metabolic retino-cerebral pathways are modulated in a coordinated fashion in response to 12A12mAb treatment to tackle the neurosensorial Aβ accumulation in AD neurodegeneration.
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Affiliation(s)
- Valentina Latina
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Anna Atlante
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Francesca Malerba
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Federico La Regina
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Bijorn Omar Balzamino
- Research Laboratories in Ophthalmology, IRCCS-Fondazione Bietti, Via Santo Stefano Rotondo 6, 00184 Rome, Italy
| | - Alessandra Micera
- Research Laboratories in Ophthalmology, IRCCS-Fondazione Bietti, Via Santo Stefano Rotondo 6, 00184 Rome, Italy
| | - Annabella Pignataro
- Institute of Translational Pharmacology (IFT), National Research Council (CNR), Via Fosso del Cavaliere 100, 00133 Rome, Italy
| | - Egidio Stigliano
- Area of Pathology, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, Istituto di Anatomia Patologica, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy
| | - Sebastiano Cavallaro
- Institute for Biomedical Research and Innovation (IRIB), National Research Council (CNR), Via P. Gaifami 18, 95126 Catania, Italy
| | - Pietro Calissano
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
| | - Giuseppina Amadoro
- European Brain Research Institute (EBRI), Viale Regina Elena 295, 00161 Rome, Italy
- Institute of Translational Pharmacology (IFT), National Research Council (CNR), Via Fosso del Cavaliere 100, 00133 Rome, Italy
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2
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Dawkins E, Derks RJE, Schifferer M, Trambauer J, Winkler E, Simons M, Paquet D, Giera M, Kamp F, Steiner H. Membrane lipid remodeling modulates γ-secretase processivity. J Biol Chem 2023; 299:103027. [PMID: 36805335 PMCID: PMC10070668 DOI: 10.1016/j.jbc.2023.103027] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 02/18/2023] Open
Abstract
Imbalances in the amounts of amyloid-β peptides (Aβ) generated by the membrane proteases β- and γ-secretase are considered as a trigger of Alzheimer´s disease (AD). Cell-free studies of γ-secretase have shown that increasing membrane thickness modulates Aβ generation, but it has remained unclear if these effects are translatable to cells. Here we show that the very long chain fatty acid erucic acid (EA) triggers acyl chain remodeling in AD cell models, resulting in substantial lipidome alterations which included increased esterification of EA in membrane lipids. Membrane remodeling enhanced γ-secretase processivity, resulting in the increased production of the potentially beneficial Aβ37 and/or Aβ38 species in multiple cell lines. Unexpectedly, we found that the membrane remodeling stimulated total Aβ secretion by cells expressing WT γ-secretase, but lowered it for cells expressing an aggressive familial AD mutant γ-secretase. We conclude that EA-mediated modulation of membrane composition is accompanied by complex lipid homeostatic changes that can impact amyloidogenic processing in different ways and elicit distinct γ-secretase responses, providing critical implications for lipid-based AD treatment strategies.
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Affiliation(s)
- Edgar Dawkins
- Division of Metabolic Biochemistry, Faculty of Medicine, Biomedical Center (BMC), LMU Munich, Munich, Germany
| | - Rico J E Derks
- Center for Proteomics & Metabolomics, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Martina Schifferer
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Johannes Trambauer
- Division of Metabolic Biochemistry, Faculty of Medicine, Biomedical Center (BMC), LMU Munich, Munich, Germany
| | - Edith Winkler
- Division of Metabolic Biochemistry, Faculty of Medicine, Biomedical Center (BMC), LMU Munich, Munich, Germany
| | - Mikael Simons
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Munich Cluster of Systems Neurology (SyNergy), Munich, Germany; Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany
| | - Dominik Paquet
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany; Institute for Stroke and Dementia Research, University Hospital, LMU Munich, Munich, Germany
| | - Martin Giera
- Center for Proteomics & Metabolomics, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Frits Kamp
- Division of Metabolic Biochemistry, Faculty of Medicine, Biomedical Center (BMC), LMU Munich, Munich, Germany
| | - Harald Steiner
- Division of Metabolic Biochemistry, Faculty of Medicine, Biomedical Center (BMC), LMU Munich, Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.
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Kabir ER, Chowdhury NM, Yasmin H, Kabir MT, Akter R, Perveen A, Ashraf GM, Akter S, Rahman MH, Sweilam SH. Unveiling the Potential of Polyphenols as Anti-Amyloid Molecules in Alzheimer's Disease. Curr Neuropharmacol 2023; 21:787-807. [PMID: 36221865 PMCID: PMC10227919 DOI: 10.2174/1570159x20666221010113812] [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: 02/23/2022] [Revised: 08/03/2022] [Accepted: 08/15/2022] [Indexed: 11/22/2022] Open
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disease that mostly affects the elderly population. Mechanisms underlying AD pathogenesis are yet to be fully revealed, but there are several hypotheses regarding AD. Even though free radicals and inflammation are likely to be linked with AD pathogenesis, still amyloid-beta (Aβ) cascade is the dominant hypothesis. According to the Aβ hypothesis, a progressive buildup of extracellular and intracellular Aβ aggregates has a significant contribution to the AD-linked neurodegeneration process. Since Aβ plays an important role in the etiology of AD, therefore Aβ-linked pathways are mainly targeted in order to develop potential AD therapies. Accumulation of Aβ plaques in the brains of AD individuals is an important hallmark of AD. These plaques are mainly composed of Aβ (a peptide of 39-42 amino acids) aggregates produced via the proteolytic cleavage of the amyloid precursor protein. Numerous studies have demonstrated that various polyphenols (PPHs), including cyanidins, anthocyanins, curcumin, catechins and their gallate esters were found to markedly suppress Aβ aggregation and prevent the formation of Aβ oligomers and toxicity, which is further suggesting that these PPHs might be regarded as effective therapeutic agents for the AD treatment. This review summarizes the roles of Aβ in AD pathogenesis, the Aβ aggregation pathway, types of PPHs, and distribution of PPHs in dietary sources. Furthermore, we have predominantly focused on the potential of food-derived PPHs as putative anti-amyloid drugs.
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Affiliation(s)
- Eva Rahman Kabir
- School of Pharmacy, BRAC University, 66 Mohakhali, Dhaka 1212, Bangladesh
| | | | - Hasina Yasmin
- School of Pharmacy, BRAC University, 66 Mohakhali, Dhaka 1212, Bangladesh
| | - Md. Tanvir Kabir
- School of Pharmacy, BRAC University, 66 Mohakhali, Dhaka 1212, Bangladesh
| | - Rokeya Akter
- Department of Pharmacy, Jagannath University, Dhaka, Bangladesh
| | - Asma Perveen
- Glocal School of Life Sciences, Glocal University, Mirzapur Pole, Saharanpur, Uttar Pradesh, India
| | - Ghulam Md. Ashraf
- Department of Medical Laboratory Sciences, College of Health Sciences, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Shamima Akter
- Department of Bioinformatics and Computational Biology, George Mason University, Fairfax, Virginia 22030, USA
| | | | - Sherouk Hussein Sweilam
- Department of Pharmacognosy, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
- Department of Pharmacognosy, Faculty of Pharmacy, Egyptian Russian University, Cairo-Suez Road, Badr City 11829, Egypt
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Amylin and Secretases in the Pathology and Treatment of Alzheimer's Disease. Biomolecules 2022; 12:biom12070996. [PMID: 35883551 PMCID: PMC9312829 DOI: 10.3390/biom12070996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/11/2022] [Accepted: 07/15/2022] [Indexed: 11/17/2022] Open
Abstract
Alzheimer’s disease remains a prevailing neurodegenerative condition which has an array physical, emotional, and financial consequences to patients and society. In the past decade, there has been a greater degree of investigation on therapeutic small peptides. This group of biomolecules have a profile of fundamentally sound characteristics which make them an intriguing area for drug development. Among these biomolecules, there are four modulatory mechanisms of interest in this review: alpha-, beta-, gamma-secretases, and amylin. These protease-based biomolecules all have a contributory role in the amyloid cascade hypothesis. Moreover, the involvement of various biochemical pathways intertwines these peptides to have shared regulators (i.e., retinoids). Further clinical and translational investigation must occur to gain a greater understanding of its potential application in patient care. The aim of this narrative review is to evaluate the contemporary literature on these protease biomolecule modulators and determine its utility in the treatment of Alzheimer’s disease.
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Cannavo C, Cleverley K, Maduro C, Mumford P, Moulding D, Fisher EMC, Wiseman FK. Endosomal structure and APP biology are not altered in a preclinical mouse cellular model of Down syndrome. PLoS One 2022; 17:e0262558. [PMID: 35544526 PMCID: PMC9094519 DOI: 10.1371/journal.pone.0262558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 04/21/2022] [Indexed: 11/18/2022] Open
Abstract
Individuals who have Down syndrome (trisomy 21) are at greatly increased risk of developing Alzheimer's disease, characterised by the accumulation in the brain of amyloid-β plaques. Amyloid-β is a product of the processing of the amyloid precursor protein, encoded by the APP gene on chromosome 21. In Down syndrome the first site of amyloid-β accumulation is within endosomes, and changes to endosome biology occur early in Alzheimer's disease. Here, we determine if primary mouse embryonic fibroblasts isolated from a mouse model of Down syndrome can be used to study endosome and APP cell biology. We report that in this cellular model, endosome number, size and APP processing are not altered, likely because APP is not dosage sensitive in the model, despite three copies of App.
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Affiliation(s)
- Claudia Cannavo
- UK Dementia Research Institute, UCL Queen Square Institute of Neurology, London, United Kingdom
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Karen Cleverley
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Cheryl Maduro
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Paige Mumford
- UK Dementia Research Institute, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Dale Moulding
- Light Microscopy Core Facility, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Elizabeth M. C. Fisher
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Frances K. Wiseman
- UK Dementia Research Institute, UCL Queen Square Institute of Neurology, London, United Kingdom
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6
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Aow J, Huang TR, Thinakaran G, Koo EH. Enhanced cleavage of APP by co-expressed Bace1 alters the distribution of APP and its fragments in neuronal and non-neuronal cells. Mol Neurobiol 2022; 59:3073-3090. [PMID: 35266114 DOI: 10.1007/s12035-022-02733-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 01/04/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND Alzheimer's disease amyloid-beta peptides (Aβ) are generated via sequential cleavage of the amyloid precursor protein (APP) by β-secretase (Bace1) and γ-secretase. Though the precise subcellular location(s) of Bace1-mediated APP cleavage remains unresolved, current models suggest APP internalization into Bace1-containing endosomes is a critical step. However, direct evidence for this model is lacking, and previous reports that probed the APP/Bace1 interaction (using co-expressed APP and Bace1 differentially labeled with fluorescent protein tags) did not determine if APP fluorescence originated from full-length APP (fl-APP) molecules that had internalized from the cell surface pool. METHODS We adapted the bungarotoxin-ligand (BTX) system to label surface APP and track internalized fluorescent APP/BTX puncta in rodent primary neurons co-expressing fluorescently-tagged Bace1. Subsequently, we employed imaging and biochemical-based approaches to measure N- and C-terminal APP epitope levels in primary neurons, N2a neuroblastoma, and HeLa cell lines. RESULTS We hypothesized that surface-labeled APP/BTX puncta would, upon internalization, colocalize with fluorescently-tagged Bace1. Unexpectedly, we observed a dramatic loss of internalized APP in co-transfected neurons and ~ 80-90% loss of surface-resident fl-APP, which we also observed in HeLa and N2a cells. Loss of surface fl-APP could be reversed by a Bace1 inhibitor, suggesting that enhanced Bace1-mediated APP cleavage was responsible for the altered processing and mis-sorting. Importantly, in a C-terminally-tagged APP construct, the majority of C-terminal fluorescence was preserved in HeLa cells despite the loss of N-terminal APP signal. This phenomenon was not only recapitulated in cultured neurons, but also showed a progressive disappearance of the APP N-terminal tag, reflecting continual cleavage of fl-APP by Bace1 away from the cell body. CONCLUSIONS Our results strongly suggested that in APP/Bace1 co-expression approaches, there was significant early and aberrant Bace1-mediated APP cleavage that perturbed fl-APP trafficking from the secretory pathway onwards, resulting in a substantial loss of surface fl-APP, which in turn led to a marked reduction in APP internalization. In C-terminally-tagged APP constructs, a large fraction of the APP fluorescence signal therefore likely arose from fluorescently-tagged β-C-terminal-fragment (β-CTF) or downstream proteolytic derivatives instead of fl-APP. Thus, care is needed in interpreting results where APP is detected only with a C-terminal tag in the presence of Bace1 co-expression, and previous findings may need to be reinterpreted if it is unclear whether fl-APP is present in normal physiological levels.
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Affiliation(s)
- Jonathan Aow
- Agency for Science, Technology and Research (A*STAR), Genome Institute of Singapore, Singapore, Singapore.
- Department of Medicine, National University of Singapore, Singapore, Singapore.
| | - Tzu-Rung Huang
- Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore
| | - Gopal Thinakaran
- USF Health Byrd Alzheimer's Center and Research Institute and Department of Molecular Medicine, University of South Florida, Tampa, FL, USA
| | - Edward H Koo
- Department of Medicine, National University of Singapore, Singapore, Singapore.
- Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore.
- Department of Neurosciences, University of California San Diego, San Diego, CA, USA.
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7
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Singh R, Kaur N, Dhingra N, Kaur T. Protein misfolding, ER Stress and Chaperones: An approach to develop chaperone-based therapeutics for Alzheimer's Disease. Int J Neurosci 2021:1-21. [PMID: 34402740 DOI: 10.1080/00207454.2021.1968859] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Alzheimer's disease (AD) is a heterogeneous neurodegenerative disorder with complex etiology that eventually leads to dementia. The main culprit of AD is the extracellular deposition of β-amyloid (Aβ) and intracellular neurofibrillary tangles. The protein conformational change and protein misfolding are the key events of AD pathophysiology, therefore endoplasmic reticulum (ER) stress is an apparent consequence. ER, stress-induced unfolded protein response (UPR) mediators (viz. PERK, IRE1, and ATF6) have been reported widely in the AD brain. Considering these factors, preventing proteins misfolding or aggregation of tau or amyloidogenic proteins appears to be the best approach to halt its pathogenesis. Therefore, therapies through chemical and pharmacological chaperones came to light as an alternative for the treatment of AD. Diverse studies have demonstrated 4-phenylbutyric acid (4-PBA) as a potential therapeutic agent in AD. The current review outlined the mechanism of protein misfolding, different etiological features behind the progression of AD, the significance of ER stress in AD, and the potential therapeutic role of different chaperones to counter AD. The study also highlights the gaps in current knowledge of the chaperones-based therapeutic approach and the possibility of developing chaperones as a potential therapeutic agent for AD treatment.
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Affiliation(s)
- Rimaljot Singh
- Department of Biophysics, Panjab University Chandigarh, India
| | - Navpreet Kaur
- Department of Biophysics, Panjab University Chandigarh, India
| | - Neelima Dhingra
- University Institute of Pharmaceutical Sciences, Panjab University Chandigarh, India
| | - Tanzeer Kaur
- Department of Biophysics, Panjab University Chandigarh, India
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Capone R, Tiwari A, Hadziselimovic A, Peskova Y, Hutchison JM, Sanders CR, Kenworthy AK. The C99 domain of the amyloid precursor protein resides in the disordered membrane phase. J Biol Chem 2021; 296:100652. [PMID: 33839158 PMCID: PMC8113881 DOI: 10.1016/j.jbc.2021.100652] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 04/02/2021] [Accepted: 04/07/2021] [Indexed: 12/11/2022] Open
Abstract
Processing of the amyloid precursor protein (APP) via the amyloidogenic pathway is associated with the etiology of Alzheimer's disease. The cleavage of APP by β-secretase to generate the transmembrane 99-residue C-terminal fragment (C99) and subsequent processing of C99 by γ-secretase to yield amyloid-β (Aβ) peptides are essential steps in this pathway. Biochemical evidence suggests that amyloidogenic processing of C99 occurs in cholesterol- and sphingolipid-enriched liquid-ordered phase membrane rafts. However, direct evidence that C99 preferentially associates with these rafts has remained elusive. Here, we tested this by quantifying the affinity of C99-GFP for raft domains in cell-derived giant plasma membrane vesicles (GPMVs). We found that C99 was essentially excluded from ordered domains in vesicles from HeLa cells, undifferentiated SH-SY5Y cells, or SH-SY5Y-derived neurons; instead, ∼90% of C99 partitioned into disordered domains. The strong association of C99 with disordered domains occurred independently of its cholesterol-binding activity or homodimerization, or of the presence of the familial Alzheimer disease Arctic mutation (APP E693G). Finally, through biochemical studies we confirmed previous results, which showed that C99 is processed in the plasma membrane by α-secretase, in addition to the well-known γ-secretase. These findings suggest that C99 itself lacks an intrinsic affinity for raft domains, implying that either i) amyloidogenic processing of the protein occurs in disordered regions of the membrane, ii) processing involves a marginal subpopulation of C99 found in rafts, or iii) as-yet-unidentified protein-protein interactions with C99 in living cells drive this protein into membrane rafts to promote its cleavage therein.
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Affiliation(s)
- Ricardo Capone
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Ajit Tiwari
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Yelena Peskova
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
| | - James M Hutchison
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Charles R Sanders
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA; Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Anne K Kenworthy
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA.
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9
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Ayton S, Bush AI. β-amyloid: The known unknowns. Ageing Res Rev 2021; 65:101212. [PMID: 33188924 DOI: 10.1016/j.arr.2020.101212] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/04/2020] [Accepted: 11/06/2020] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) stands out as a major disease without any form of preventative or disease modifying therapy. This is not for lack of trying. 33 phase 3 clinical trials of drugs targeting amyloid beta (Aβ) have failed to slow cognitive decline in AD. The field is at a cross-roads about whether to continue anti-Aβ therapy or more actively pursue alternative targets. With the burden of this disease to patients, families, and healthcare budgets growing yearly, the need for disease modifying AD therapies has become one of the highest priorities in all of medicine. While pathology, genetic and biochemical data offer a popular narrative for the causative role of Aβ, there are alternative explanations, and dissenting findings that, now more than ever, warrant thorough reanalysis. This review questions the major assumptions about Aβ on which therapies for AD were premised, and invites renewed interrogation into AD pathogenesis.
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Affiliation(s)
- Scott Ayton
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3052, Australia.
| | - Ashley I Bush
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3052, Australia.
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10
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Wei W, Wang ZY, Ma LN, Zhang TT, Cao Y, Li H. MicroRNAs in Alzheimer's Disease: Function and Potential Applications as Diagnostic Biomarkers. Front Mol Neurosci 2020; 13:160. [PMID: 32973449 PMCID: PMC7471745 DOI: 10.3389/fnmol.2020.00160] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 08/05/2020] [Indexed: 12/14/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia. Although the incidence of AD is high, the rates of diagnosis and treatment are relatively low. Moreover, effective means for the diagnosis and treatment of AD are still lacking. MicroRNAs (miRNAs, miRs) are non-coding RNAs that play regulatory roles by targeting mRNAs. The expression of miRNAs is conserved, temporal, and tissue-specific. Impairment of microRNA function is closely related to AD pathogenesis, including the beta-amyloid and tau hallmarks of AD, and there is evidence that the expression of some microRNAs differs significantly between healthy people and AD patients. These properties of miRNAs endow them with potential diagnostic and therapeutic value in the treatment of this debilitating disease. This review provides comprehensive information about the regulatory function of miRNAs in AD, as well as potential applications as diagnostic biomarkers.
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Affiliation(s)
- Wei Wei
- First Clinical College, Shandong University of Traditional Chinese Medicine, Jinan, China.,Department of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Zhi-Yong Wang
- Department of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Li-Na Ma
- Department of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Ting-Ting Zhang
- First Clinical College, Shandong University of Traditional Chinese Medicine, Jinan, China.,Department of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yu Cao
- Department of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Hao Li
- Department of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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11
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Gutierrez E, Lütjohann D, Kerksiek A, Fabiano M, Oikawa N, Kuerschner L, Thiele C, Walter J. Importance of γ-secretase in the regulation of liver X receptor and cellular lipid metabolism. Life Sci Alliance 2020; 3:3/6/e201900521. [PMID: 32354700 PMCID: PMC7195048 DOI: 10.26508/lsa.201900521] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 12/12/2022] Open
Abstract
Inhibition of the Alzheimer associated γ-secretase impairs the regulation of cellular lipid droplet homeostasis. Presenilins (PS) are the catalytic components of γ-secretase complexes that mediate intramembrane proteolysis. Mutations in the PS genes are a major cause of familial early-onset Alzheimer disease and affect the cleavage of the amyloid precursor protein, thereby altering the production of the amyloid β-peptide. However, multiple additional protein substrates have been identified, suggesting pleiotropic functions of γ-secretase. Here, we demonstrate that inhibition of γ-secretase causes dysregulation of cellular lipid homeostasis, including up-regulation of liver X receptors, and complex changes in the cellular lipid composition. Genetic and pharmacological inhibition of γsecretase leads to strong accumulation of cytoplasmic lipid droplets, associated with increased levels of acylglycerols, but lowered cholesteryl esters. Furthermore, accumulation of lipid droplets was augmented by increasing levels of amyloid precursor protein C-terminal fragments, indicating a critical involvement of this γ-secretase substrate. Together, these data provide a mechanism that functionally connects γ-secretase activity to cellular lipid metabolism. These effects were also observed in human astrocytic cells, indicating an important function of γ-secretase in cells critical for lipid homeostasis in the brain.
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Affiliation(s)
| | - Dieter Lütjohann
- Institute of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany
| | - Anja Kerksiek
- Institute of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany
| | - Marietta Fabiano
- Department of Neurology, University Hospital Bonn, Bonn, Germany
| | - Naoto Oikawa
- Department of Neurology, University Hospital Bonn, Bonn, Germany
| | - Lars Kuerschner
- Life and Medical Sciences Institute, University of Bonn, Bonn, Germany
| | - Christoph Thiele
- Life and Medical Sciences Institute, University of Bonn, Bonn, Germany
| | - Jochen Walter
- Department of Neurology, University Hospital Bonn, Bonn, Germany
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12
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Pacheco-Quinto J, Clausen D, Pérez-González R, Peng H, Meszaros A, Eckman CB, Levy E, Eckman EA. Intracellular metalloprotease activity controls intraneuronal Aβ aggregation and limits secretion of Aβ via exosomes. FASEB J 2019; 33:3758-3771. [PMID: 30481490 PMCID: PMC6404562 DOI: 10.1096/fj.201801319r] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/29/2018] [Indexed: 01/09/2023]
Abstract
Accumulating evidence suggests that the abnormal aggregation of amyloid-β (Αβ) peptide in Alzheimer's disease (AD) begins intraneuronally, within vesicles of the endosomal-lysosomal pathway where Aβ is both generated and degraded. Metalloproteases, including endothelin-converting enzyme (ECE)-1 and -2, reside within these vesicles and normally limit the accumulation of intraneuronally produced Aβ. In this study, we determined whether disruption of Aβ catabolism could trigger Aβ aggregation within neurons and increase the amount of Aβ associated with exosomes, small extracellular vesicles derived from endosomal multivesicular bodies. Using cultured cell lines, primary neurons, and organotypic brain slices from an AD mouse model, we found that pharmacological inhibition of the ECE family of metalloproteases increased intracellular and extracellular Aβ levels and promoted the intracellular formation of Aβ oligomers, a process that did not require internalization of secreted Aβ. In vivo, the accumulation of intraneuronal Aβ aggregates was accompanied by increased levels of both extracellular and exosome-associated Aβ, including oligomeric species. Neuronal exosomes were found to contain both ECE-1 and -2 activities, suggesting that multivesicular bodies are intracellular sites of Aβ degradation by these enzymes. ECE dysfunction could lead to the accumulation of intraneuronal Aβ aggregates and their subsequent release into the extracellular space via exosomes.-Pacheco-Quinto, J., Clausen, D., Pérez-González, R., Peng, H., Meszaros, A., Eckman, C. B., Levy, E., Eckman, E. A. Intracellular metalloprotease activity controls intraneuronal Aβ aggregation and limits secretion of Aβ via exosomes.
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Affiliation(s)
- Javier Pacheco-Quinto
- Biomedical Research Institute of New Jersey, Cedar Knolls, New Jersey, USA
- Atlantic Health System, Morristown, New Jersey, USA
| | - Dana Clausen
- Biomedical Research Institute of New Jersey, Cedar Knolls, New Jersey, USA
| | - Rocío Pérez-González
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, USA
- Department of Psychiatry, NYU Langone Medical Center, New York, New York, USA
| | - Hui Peng
- Biomedical Research Institute of New Jersey, Cedar Knolls, New Jersey, USA
| | - Austin Meszaros
- Biomedical Research Institute of New Jersey, Cedar Knolls, New Jersey, USA
| | | | - Efrat Levy
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, USA
- Department of Psychiatry, NYU Langone Medical Center, New York, New York, USA
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Medical Center, New York, New York, USA; and
- Neuroscience Institute, NYU Langone Medical Center, New York, New York, USA
| | - Elizabeth A. Eckman
- Biomedical Research Institute of New Jersey, Cedar Knolls, New Jersey, USA
- Atlantic Health System, Morristown, New Jersey, USA
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13
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Evrard C, Kienlen-Campard P, Coevoet M, Opsomer R, Tasiaux B, Melnyk P, Octave JN, Buée L, Sergeant N, Vingtdeux V. Contribution of the Endosomal-Lysosomal and Proteasomal Systems in Amyloid-β Precursor Protein Derived Fragments Processing. Front Cell Neurosci 2018; 12:435. [PMID: 30524243 PMCID: PMC6263093 DOI: 10.3389/fncel.2018.00435] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 11/02/2018] [Indexed: 12/31/2022] Open
Abstract
Aβ peptides, the major components of Alzheimer's disease (AD) amyloid deposits, are released following sequential cleavages by secretases of its precursor named the amyloid precursor protein (APP). In addition to secretases, degradation pathways, in particular the endosomal/lysosomal and proteasomal systems have been reported to contribute to APP processing. However, the respective role of each of these pathways toward APP metabolism remains to be established. To address this, we used HEK 293 cells and primary neurons expressing full-length wild type APP or the β-secretase-derived C99 fragment (β-CTF) in which degradation pathways were selectively blocked using pharmacological drugs. APP metabolites, including carboxy-terminal fragments (CTFs), soluble APP (sAPP) and Aβ peptides were studied. In this report, we show that APP-CTFs produced from endogenous or overexpressed full-length APP are mainly processed by γ-secretase and the endosomal/lysosomal pathway, while in sharp contrast, overexpressed C99 is mainly degraded by the proteasome and to a lesser extent by γ-secretase.
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Affiliation(s)
- Caroline Evrard
- Université de Lille, Inserm, Centre Hospitalier-Universitaire de Lille, UMR-S 1172 – Centre de Recherche Jean-Pierre Aubert, Lille, France
| | - Pascal Kienlen-Campard
- Alzheimer Research Group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Mathilde Coevoet
- Université de Lille, Inserm, Centre Hospitalier-Universitaire de Lille, UMR-S 1172 – Centre de Recherche Jean-Pierre Aubert, Lille, France
| | - Rémi Opsomer
- Alzheimer Research Group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Bernadette Tasiaux
- Alzheimer Research Group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Patricia Melnyk
- Université de Lille, Inserm, Centre Hospitalier-Universitaire de Lille, UMR-S 1172 – Centre de Recherche Jean-Pierre Aubert, Lille, France
| | - Jean-Noël Octave
- Alzheimer Research Group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Luc Buée
- Université de Lille, Inserm, Centre Hospitalier-Universitaire de Lille, UMR-S 1172 – Centre de Recherche Jean-Pierre Aubert, Lille, France
| | - Nicolas Sergeant
- Université de Lille, Inserm, Centre Hospitalier-Universitaire de Lille, UMR-S 1172 – Centre de Recherche Jean-Pierre Aubert, Lille, France
| | - Valérie Vingtdeux
- Université de Lille, Inserm, Centre Hospitalier-Universitaire de Lille, UMR-S 1172 – Centre de Recherche Jean-Pierre Aubert, Lille, France
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14
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Kamp F, Scheidt HA, Winkler E, Basset G, Heinel H, Hutchison JM, LaPointe LM, Sanders CR, Steiner H, Huster D. Bexarotene Binds to the Amyloid Precursor Protein Transmembrane Domain, Alters Its α-Helical Conformation, and Inhibits γ-Secretase Nonselectively in Liposomes. ACS Chem Neurosci 2018; 9:1702-1713. [PMID: 29717863 DOI: 10.1021/acschemneuro.8b00068] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Bexarotene is a pleiotropic molecule that has been proposed as an amyloid-β (Aβ)-lowering drug for the treatment of Alzheimer's disease (AD). It acts by upregulation of an apolipoprotein E (apoE)-mediated Aβ clearance mechanism. However, whether bexarotene induces removal of Aβ plaques in mouse models of AD has been controversial. Here, we show by NMR and CD spectroscopy that bexarotene directly interacts with and stabilizes the transmembrane domain α-helix of the amyloid precursor protein (APP) in a region where cholesterol binds. This effect is not mediated by changes in membrane lipid packing, as bexarotene does not share with cholesterol the property of inducing phospholipid condensation. Bexarotene inhibited the intramembrane cleavage by γ-secretase of the APP C-terminal fragment C99 to release Aβ in cell-free assays of the reconstituted enzyme in liposomes, but not in cells, and only at very high micromolar concentrations. Surprisingly, in vitro, bexarotene also inhibited the cleavage of Notch1, another major γ-secretase substrate, demonstrating that its inhibition of γ-secretase is not substrate specific and not mediated by acting via the cholesterol binding site of C99. Our data suggest that bexarotene is a pleiotropic molecule that interfere with Aβ metabolism through multiple mechanisms.
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Affiliation(s)
- Frits Kamp
- Biomedical Center - BMC, Metabolic Biochemistry, Ludwig-Maximilians University, Munich 80539, Germany
| | - Holger A. Scheidt
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, D-04107 Leipzig, Germany
| | - Edith Winkler
- Biomedical Center - BMC, Metabolic Biochemistry, Ludwig-Maximilians University, Munich 80539, Germany
| | - Gabriele Basset
- Biomedical Center - BMC, Metabolic Biochemistry, Ludwig-Maximilians University, Munich 80539, Germany
| | - Hannes Heinel
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, D-04107 Leipzig, Germany
| | - James M. Hutchison
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Loren M. LaPointe
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Charles R. Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Harald Steiner
- Biomedical Center - BMC, Metabolic Biochemistry, Ludwig-Maximilians University, Munich 80539, Germany
- German Center for Neurodegenerative Diseases (DZNE)−Munich, Feodor-Lynen-Str. 17, D-81377 Munich, Germany
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, D-04107 Leipzig, Germany
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15
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Siegel G, Gerber H, Koch P, Bruestle O, Fraering PC, Rajendran L. The Alzheimer's Disease γ-Secretase Generates Higher 42:40 Ratios for β-Amyloid Than for p3 Peptides. Cell Rep 2018; 19:1967-1976. [PMID: 28591569 DOI: 10.1016/j.celrep.2017.05.034] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/12/2017] [Accepted: 05/09/2017] [Indexed: 12/25/2022] Open
Abstract
Alzheimer's disease is characterized by intracerebral deposition of β-amyloid (Aβ). While Aβ40 is the most abundant form, neurotoxicity is mainly mediated by Aβ42. Sequential cleavage of amyloid precursor protein (APP) by β- and γ-secretases gives rise to full-length Aβ (Aβ1-x) and N-terminally truncated Aβ' (Aβ11-x) whereas cleavage by α- and γ-secretases leads to the shorter p3 peptides (Aβ17-x). We uncovered significantly higher ratios of 42- versus 40-ending variants for Aβ and Aβ' than for p3 secreted by mouse neurons and human induced pluripotent stem cell (iPSC)-derived neurons or produced in a cell-free γ-secretase assay with recombinant APP-CTFs. The 42:40 ratio was highest for Aβ', followed by Aβ and then p3. Mass spectrometry analysis of APP intracellular domains revealed differential processing of APP-C83, APP-C89, and APP-C99 by γ-secretase already at the ε-cleavage stage. This mechanistic insight could aid in developing substrate-targeted modulators of APP-C99 processing to specifically lower the Aβ42:Aβ40 ratio without compromising γ-secretase function.
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Affiliation(s)
- Gabriele Siegel
- Systems and Cell Biology of Neurodegeneration, IREM, University of Zurich, Schlieren Campus, 8952 Schlieren, Switzerland.
| | - Hermeto Gerber
- Foundation Eclosion, 1228 Plan-les-Ouates & Campus Biotech Innovation Park, 1202 Geneva, Switzerland; Brain Mind Institute and School of Life Sciences, Swiss Federal Institute of Technology (EPFL), 1015 Lausanne, Switzerland; Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Philipp Koch
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty, 53127 Bonn, Germany; LIFE & BRAIN GmbH, 53127 Bonn, Germany
| | - Oliver Bruestle
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty, 53127 Bonn, Germany; LIFE & BRAIN GmbH, 53127 Bonn, Germany
| | - Patrick C Fraering
- Foundation Eclosion, 1228 Plan-les-Ouates & Campus Biotech Innovation Park, 1202 Geneva, Switzerland; Brain Mind Institute and School of Life Sciences, Swiss Federal Institute of Technology (EPFL), 1015 Lausanne, Switzerland
| | - Lawrence Rajendran
- Systems and Cell Biology of Neurodegeneration, IREM, University of Zurich, Schlieren Campus, 8952 Schlieren, Switzerland.
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16
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Small SA, Simoes-Spassov S, Mayeux R, Petsko GA. Endosomal Traffic Jams Represent a Pathogenic Hub and Therapeutic Target in Alzheimer's Disease. Trends Neurosci 2018; 40:592-602. [PMID: 28962801 DOI: 10.1016/j.tins.2017.08.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 08/21/2017] [Accepted: 08/21/2017] [Indexed: 12/19/2022]
Abstract
While clues have existed that endosomal trafficking is associated with Alzheimer's disease (AD), whether it plays a central role in the disease and if so how has remained unknown. Here we rely on recent genetic and cellular findings to construct a model proposing that traffic jams in the early endosome can act as an upstream pathogenic hub in AD. We also rely on an independent series of findings to suggest how the traffic jams can act as a unified mediator of downstream pathophysiology. The model predicts, therefore, that interventions designed to unjam the endosome carry high therapeutic promise.
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Affiliation(s)
- Scott A Small
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA; Department of Neurology, Columbia University, New York, NY, USA.
| | - Sabrina Simoes-Spassov
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA; Department of Neurology, Columbia University, New York, NY, USA
| | - Richard Mayeux
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA; Department of Neurology, Columbia University, New York, NY, USA
| | - Gregory A Petsko
- Helen and Robert Appel Alzheimer's Disease Research Institute, Weill Cornell Medical College, New York, NY, USA
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17
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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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18
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Trafficking in Alzheimer's Disease: Modulation of APP Transport and Processing by the Transmembrane Proteins LRP1, SorLA, SorCS1c, Sortilin, and Calsyntenin. Mol Neurobiol 2017; 55:5809-5829. [PMID: 29079999 DOI: 10.1007/s12035-017-0806-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/17/2017] [Indexed: 12/11/2022]
Abstract
The amyloid precursor protein (APP), one key player in Alzheimer's disease (AD), is extensively processed by different proteases. This leads to the generation of diverging fragments including the amyloid β (Aβ) peptide, which accumulates in brains of AD patients. Subcellular trafficking of APP is an important aspect for its proteolytic conversion, since the various secretases which cleave APP are located in different cellular compartments. As a consequence, altered subcellular targeting of APP is thought to directly affect the degree to which Aβ is generated. The mechanisms underlying intracellular APP transport are critical to understand AD pathogenesis and can serve as a target for future pharmacological interventions. In the recent years, a number of APP interacting proteins were identified which are implicated in sorting of APP, thereby influencing APP processing at different angles of the secretory or endocytic pathway. This review provides an update on the proteolytic processing of APP and the interplay of the transmembrane proteins low-density lipoprotein receptor-related protein 1, sortilin-receptor with A-type repeats, SorCS1c, sortilin, and calsyntenin. We discuss the specific interactions with APP, the capacity to modulate the intracellular itinerary and the proteolytic conversion of APP, a possible involvement in the clearance of Aβ, and the implications of these transmembrane proteins in AD and other neurodegenerative diseases.
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19
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Siebel C, Lendahl U. Notch Signaling in Development, Tissue Homeostasis, and Disease. Physiol Rev 2017; 97:1235-1294. [PMID: 28794168 DOI: 10.1152/physrev.00005.2017] [Citation(s) in RCA: 598] [Impact Index Per Article: 85.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/19/2017] [Accepted: 05/26/2017] [Indexed: 02/07/2023] Open
Abstract
Notch signaling is an evolutionarily highly conserved signaling mechanism, but in contrast to signaling pathways such as Wnt, Sonic Hedgehog, and BMP/TGF-β, Notch signaling occurs via cell-cell communication, where transmembrane ligands on one cell activate transmembrane receptors on a juxtaposed cell. Originally discovered through mutations in Drosophila more than 100 yr ago, and with the first Notch gene cloned more than 30 yr ago, we are still gaining new insights into the broad effects of Notch signaling in organisms across the metazoan spectrum and its requirement for normal development of most organs in the body. In this review, we provide an overview of the Notch signaling mechanism at the molecular level and discuss how the pathway, which is architecturally quite simple, is able to engage in the control of cell fates in a broad variety of cell types. We discuss the current understanding of how Notch signaling can become derailed, either by direct mutations or by aberrant regulation, and the expanding spectrum of diseases and cancers that is a consequence of Notch dysregulation. Finally, we explore the emerging field of Notch in the control of tissue homeostasis, with examples from skin, liver, lung, intestine, and the vasculature.
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Affiliation(s)
- Chris Siebel
- Department of Discovery Oncology, Genentech Inc., DNA Way, South San Francisco, California; and Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Urban Lendahl
- Department of Discovery Oncology, Genentech Inc., DNA Way, South San Francisco, California; and Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
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20
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Wang X, Zhou X, Li G, Zhang Y, Wu Y, Song W. Modifications and Trafficking of APP in the Pathogenesis of Alzheimer's Disease. Front Mol Neurosci 2017; 10:294. [PMID: 28966576 PMCID: PMC5605621 DOI: 10.3389/fnmol.2017.00294] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/31/2017] [Indexed: 12/31/2022] Open
Abstract
Alzheimer's disease (AD), the most common neurodegenerative disorder, is the leading cause of dementia. Neuritic plaque, one of the major characteristics of AD neuropathology, mainly consists of amyloid β (Aβ) protein. Aβ is derived from amyloid precursor protein (APP) by sequential cleavages of β- and γ-secretase. Although APP upregulation can promote AD pathogenesis by facilitating Aβ production, growing evidence indicates that aberrant post-translational modifications and trafficking of APP play a pivotal role in AD pathogenesis by dysregulating APP processing and Aβ generation. In this report, we reviewed the current knowledge of APP modifications and trafficking as well as their role in APP processing. More importantly, we discussed the effect of aberrant APP modifications and trafficking on Aβ generation and the underlying mechanisms, which may provide novel strategies for drug development in AD.
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Affiliation(s)
- Xin Wang
- Department of Psychiatry, Jining Medical UniversityJining, China.,Shandong Key Laboratory of Behavioral Medicine, Jining Medical UniversityJining, China
| | - Xuan Zhou
- Department of Psychiatry, Jining Medical UniversityJining, China.,Shandong Key Laboratory of Behavioral Medicine, Jining Medical UniversityJining, China
| | - Gongying Li
- Department of Psychiatry, Jining Medical UniversityJining, China.,Shandong Key Laboratory of Behavioral Medicine, Jining Medical UniversityJining, China.,Collaborative Innovation Center for Birth Defect Research and Transformation of Shandong Province, Jining Medical UniversityJining, China
| | - Yun Zhang
- Townsend Family Laboratories, Department of Psychiatry, The University of British ColumbiaVancouver, BC, Canada
| | - Yili Wu
- Department of Psychiatry, Jining Medical UniversityJining, China.,Shandong Key Laboratory of Behavioral Medicine, Jining Medical UniversityJining, China.,Collaborative Innovation Center for Birth Defect Research and Transformation of Shandong Province, Jining Medical UniversityJining, China.,Townsend Family Laboratories, Department of Psychiatry, The University of British ColumbiaVancouver, BC, Canada
| | - Weihong Song
- Townsend Family Laboratories, Department of Psychiatry, The University of British ColumbiaVancouver, BC, Canada
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21
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Baranger K, Bonnet AE, Girard SD, Paumier JM, García-González L, Elmanaa W, Bernard A, Charrat E, Stephan D, Bauer C, Moschke K, Lichtenthaler SF, Roman FS, Checler F, Khrestchatisky M, Rivera S. MT5-MMP Promotes Alzheimer's Pathogenesis in the Frontal Cortex of 5xFAD Mice and APP Trafficking in vitro. Front Mol Neurosci 2017; 9:163. [PMID: 28119565 PMCID: PMC5223243 DOI: 10.3389/fnmol.2016.00163] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 12/16/2016] [Indexed: 12/18/2022] Open
Abstract
We previously reported that deficiency of membrane-type five matrix metalloproteinase (MT5-MMP) prevents amyloid pathology in the cortex and hippocampus of 5xFAD mice, and ameliorates the functional outcome. We have now investigated whether the integrity of another important area affected in Alzheimer's disease (AD), the frontal cortex, was also preserved upon MT5-MMP deficiency in 4-month old mice at prodromal stages of the pathology. We used the olfactory H-maze (OHM) to show that learning impairment associated with dysfunctions of the frontal cortex in 5xFAD was prevented in bigenic 5xFAD/MT5-MMP-/- mice. The latter exhibited concomitant drastic reductions of amyloid beta peptide (Aβ) assemblies (soluble, oligomeric and fibrillary) and its immediate precursor, C99. Simultaneously, astrocyte reactivity and tumor necrosis factor alpha (TNF-α) levels were also lowered. Moreover, MT5-MMP deficiency induced a decrease in N-terminal soluble fragments of amyloid precursor protein (APP), including soluble APPα (sAPPα), sAPPβ and the MT5-MMP-linked fragment of 95 kDa, sAPP95. However, the lack of MT5-MMP did not affect the activity of β- and γ-secretases. In cultured HEKswe cells, transiently expressed MT5-MMP localized to early endosomes and increased the content of APP and Aβ40 in these organelles, as well as Aβ levels in cell supernatants. This is the first evidence that the pro-amyloidogenic features of MT5-MMP lie, at least in part, on the ability of the proteinase to promote trafficking into one of the amyloidogenic subcellular loci. Together, our data further support the pathogenic role of MT5-MMP in AD and that its inhibition improves the functional and pathological outcomes, in this case in the frontal cortex. These data also support the idea that MT5-MMP could become a novel therapeutic target in AD.
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Affiliation(s)
- Kévin Baranger
- Aix Marseille Université, CNRS, NICN UMR 7259 Marseille, France
| | | | | | | | | | - Wejdane Elmanaa
- Université Côte d'Azur, INSERM, CNRS, IPMC, Laboratory of excellence DistALZ, Sophia-Antipolis Valbonne, France
| | - Anne Bernard
- Aix Marseille Université, CNRS, NICN UMR 7259 Marseille, France
| | - Eliane Charrat
- Aix Marseille Université, CNRS, NICN UMR 7259 Marseille, France
| | | | - Charlotte Bauer
- Université Côte d'Azur, INSERM, CNRS, IPMC, Laboratory of excellence DistALZ, Sophia-Antipolis Valbonne, France
| | - Katrin Moschke
- German Center for Neurodegenerative Diseases (DZNE) Munich, Germany
| | - Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE)Munich, Germany; Neuroproteomics, Klinikum rechts der Isar, and Institute for Advanced Study, Technische Universität München (TUM)Munich, Germany; Munich Cluster for Systems Neurology (SyNergy)Munich, Germany
| | | | - Frédéric Checler
- Université Côte d'Azur, INSERM, CNRS, IPMC, Laboratory of excellence DistALZ, Sophia-Antipolis Valbonne, France
| | | | - Santiago Rivera
- Aix Marseille Université, CNRS, NICN UMR 7259 Marseille, France
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22
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Kanatsu K, Tomita T. Membrane trafficking and proteolytic activity of γ-secretase in Alzheimer’s disease. Biol Chem 2016; 397:827-35. [DOI: 10.1515/hsz-2016-0146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 07/04/2016] [Indexed: 12/26/2022]
Abstract
Abstract
γ-Secretase is an intramembrane-cleaving protease that generates various forms of amyloid-β peptides (Aβ) that accumulate in the brains of Alzheimer’s disease (AD) patients. The intracellular trafficking and subcellular localization of γ-secretase are linked to both qualitative and quantitative changes in Aβ production. However, the precise intracellular localization of γ-secretase as well as its detailed regulatory mechanisms have remained elusive. Recent genetic studies on AD provide ample evidence that alteration of the subcellular localization of γ-secretase contributes to the pathogenesis of AD. Here we review our current understanding of the intracellular membrane trafficking of γ-secretase, the association between its localization and proteolytic activity, and the possibility of γ-secretase as a therapeutic target against AD.
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23
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Avci D, Lemberg MK. Clipping or Extracting: Two Ways to Membrane Protein Degradation. Trends Cell Biol 2016; 25:611-622. [PMID: 26410407 DOI: 10.1016/j.tcb.2015.07.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 06/18/2015] [Accepted: 07/17/2015] [Indexed: 12/20/2022]
Abstract
Protein degradation is a fundamentally important process that allows cells to recognize and remove damaged protein species and to regulate protein abundance according to functional need. A fundamental challenge is to understand how membrane proteins are recognized and removed from cellular organelles. While most of our understanding of this mechanism comes from studies on p97/Cdc48-mediated protein dislocation along the endoplasmic reticulum (ER)-associated degradation (ERAD) pathway, recent studies have revealed intramembrane proteolysis to be an additional mechanism that can extract transmembrane segments. Here, we review these two principles in membrane protein degradation and discuss how intramembrane proteolysis, which introduces an irreversible step in protein dislocation, is used to drive regulated protein turnover.
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Affiliation(s)
- Dönem Avci
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Marius K Lemberg
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany.
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24
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Xu W, Weissmiller AM, White JA, Fang F, Wang X, Wu Y, Pearn ML, Zhao X, Sawa M, Chen S, Gunawardena S, Ding J, Mobley WC, Wu C. Amyloid precursor protein-mediated endocytic pathway disruption induces axonal dysfunction and neurodegeneration. J Clin Invest 2016; 126:1815-33. [PMID: 27064279 PMCID: PMC4855914 DOI: 10.1172/jci82409] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 02/24/2016] [Indexed: 12/17/2022] Open
Abstract
The endosome/lysosome pathway is disrupted early in the course of both Alzheimer's disease (AD) and Down syndrome (DS); however, it is not clear how dysfunction in this pathway influences the development of these diseases. Herein, we explored the cellular and molecular mechanisms by which endosomal dysfunction contributes to the pathogenesis of AD and DS. We determined that full-length amyloid precursor protein (APP) and its β-C-terminal fragment (β-CTF) act though increased activation of Rab5 to cause enlargement of early endosomes and to disrupt retrograde axonal trafficking of nerve growth factor (NGF) signals. The functional impacts of APP and its various products were investigated in PC12 cells, cultured rat basal forebrain cholinergic neurons (BFCNs), and BFCNs from a mouse model of DS. We found that the full-length wild-type APP (APPWT) and β-CTF both induced endosomal enlargement and disrupted NGF signaling and axonal trafficking. β-CTF alone induced atrophy of BFCNs that was rescued by the dominant-negative Rab5 mutant, Rab5S34N. Moreover, expression of a dominant-negative Rab5 construct markedly reduced APP-induced axonal blockage in Drosophila. Therefore, increased APP and/or β-CTF impact the endocytic pathway to disrupt NGF trafficking and signaling, resulting in trophic deficits in BFCNs. Our data strongly support the emerging concept that dysregulation of Rab5 activity contributes importantly to early pathogenesis of AD and DS.
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Affiliation(s)
- Wei Xu
- Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Neurosciences, UCSD, La Jolla, California, USA
| | | | - Joseph A. White
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, New York, USA
| | - Fang Fang
- Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Neurosciences, UCSD, La Jolla, California, USA
| | - Xinyi Wang
- Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yiwen Wu
- Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Matthew L. Pearn
- Department of Anesthesiology, UCSD, La Jolla, California, USA
- VA San Diego Healthcare System, San Diego, California, USA
| | - Xiaobei Zhao
- Department of Neurosciences, UCSD, La Jolla, California, USA
| | - Mariko Sawa
- Department of Neurosciences, UCSD, La Jolla, California, USA
| | - Shengdi Chen
- Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shermali Gunawardena
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, New York, USA
| | - Jianqing Ding
- Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | | | - Chengbiao Wu
- Department of Neurosciences, UCSD, La Jolla, California, USA
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25
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Zhang R, Ai H, Zhu X, Li Q. Molecular Simulations of Human and Mouse Aβ1-16
at Different pH Values: Structural Characteristics toward Understanding Cu2+
-Coordinated Amyloid Beta Spheres. Chemphyschem 2016; 17:1656-68. [DOI: 10.1002/cphc.201600004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Ran Zhang
- School of Chemistry and Chemical Engineering; University of Jinan; Jinan 250022 China
| | - Hongqi Ai
- School of Chemistry and Chemical Engineering; University of Jinan; Jinan 250022 China
| | - Xueying Zhu
- School of Chemistry and Chemical Engineering; University of Jinan; Jinan 250022 China
| | - Qiang Li
- School of Biological Science and Technology; University of Jinan; Jinan 250022 China
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26
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Meckler X, Checler F. Presenilin 1 and Presenilin 2 Target γ-Secretase Complexes to Distinct Cellular Compartments. J Biol Chem 2016; 291:12821-12837. [PMID: 27059953 DOI: 10.1074/jbc.m115.708297] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Indexed: 11/06/2022] Open
Abstract
γ-Secretase complexes achieve the production of amyloid peptides playing a key role in Alzheimer disease. These proteases have many substrates involved in important physiological functions. They are composed of two constant subunits, nicastrin and PEN2, and two variable ones, presenilin (PS1 or PS2) and APH1 (APH1aL, APH1aS, or APH1b). Whether the composition of a given γ-secretase complex determines a specific cellular targeting remains unsolved. Here we combined a bidirectional inducible promoter and 2A peptide technology to generate constructs for the temporary, stoichiometric co-expression of six different combinations of the four γ-secretase subunits including EGFP-tagged nicastrin. These plasmids allow for the formation of functional γ-secretase complexes displaying specific activities and maturations. We show that PS1-containing γ-secretase complexes were targeted to the plasma membrane, whereas PS2-containing ones were addressed to the trans-Golgi network, to recycling endosomes, and, depending on the APH1-variant, to late endocytic compartments. Overall, these novel constructs unravel a presenilin-dependent subcellular targeting of γ-secretase complexes. These tools should prove useful to determine whether the cellular distribution of γ-secretase complexes contributes to substrate selectivity and to delineate regulations of their trafficking.
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Affiliation(s)
- Xavier Meckler
- From the Université de Nice Sophia-Antipolis, Institut de Pharmacologie Moléculaire et Cellulaire CNRS UMR7275, Laboratoire d'Excellence Distalz, Sophia-Antipolis, 06560 Valbonne, France
| | - Frédéric Checler
- From the Université de Nice Sophia-Antipolis, Institut de Pharmacologie Moléculaire et Cellulaire CNRS UMR7275, Laboratoire d'Excellence Distalz, Sophia-Antipolis, 06560 Valbonne, France.
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27
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Hsu EC, Kulp SK, Huang HL, Tu HJ, Salunke SB, Sullivan NJ, Sun D, Wicha MS, Shapiro CL, Chen CS. Function of Integrin-Linked Kinase in Modulating the Stemness of IL-6-Abundant Breast Cancer Cells by Regulating γ-Secretase-Mediated Notch1 Activation in Caveolae. Neoplasia 2016; 17:497-508. [PMID: 26152358 PMCID: PMC4719004 DOI: 10.1016/j.neo.2015.06.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 05/19/2015] [Accepted: 06/02/2015] [Indexed: 01/02/2023] Open
Abstract
Interleukin-6 (IL-6) and Notch signaling are important regulators of breast cancer stem cells (CSCs), which drive the malignant phenotype through self-renewal, differentiation, and development of therapeutic resistance. We investigated the role of integrin-linked kinase (ILK) in regulating IL-6–driven Notch1 activation and the ability to target breast CSCs through ILK inhibition. Ectopic expression/short hairpin RNA-mediated knockdown of ILK, pharmacological inhibition of ILK with the small molecule T315, Western blot analysis, immunofluorescence, and luciferase reporter assays were used to evaluate the regulation of IL-6–driven Notch1 activation by ILK in IL-6–producing triple-negative breast cancer cell lines (MDA-MB-231, SUM-159) and in MCF-7 and MCF-7IL-6 cells. The effects of ILK on γ-secretase complex assembly and cellular localization were determined by immunofluorescence, Western blots of membrane fractions, and immunoprecipitation. In vivo effects of T315-induced ILK inhibition on CSCs in SUM-159 xenograft models were assessed by mammosphere assays, flow cytometry, and tumorigenicity assays. Results show that the genetic knockdown or pharmacological inhibition of ILK suppressed Notch1 activation and the abundance of the γ-secretase components presenilin-1, nicastrin, and presenilin enhancer 2 at the posttranscriptional level via inhibition of caveolin-1-dependent membrane assembly of the γ-secretase complex. Accordingly, knockdown of ILK inhibited breast CSC-like properties in vitro and the breast CSC subpopulation in vivo in xenograft tumor models. Based on these findings, we propose a novel function of ILK in regulating γ-secretase–mediated Notch1 activation, which suggests the targeting of ILK as a therapeutic approach to suppress IL-6–induced breast CSCs.
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Affiliation(s)
- En-Chi Hsu
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA
| | - Samuel K Kulp
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA
| | - Han-Li Huang
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA
| | - Huang-Ju Tu
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA
| | - Santosh B Salunke
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA
| | - Nicholas J Sullivan
- Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA
| | - Duxin Sun
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI, USA
| | - Max S Wicha
- Department of Internal Medicine, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI, USA
| | - Charles L Shapiro
- Division of Medical Oncology, Department of Internal Medicine, College of Medicine, The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA
| | - Ching-Shih Chen
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA; Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
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28
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Regulation of Notch Signaling Through Intracellular Transport. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 323:107-27. [PMID: 26944620 DOI: 10.1016/bs.ircmb.2015.12.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The highly conserved Notch-signaling pathway performs a central role in cell differentiation, survival, and proliferation. A major mechanism by which cells modulate signaling is by controlling the intracellular transport itinerary of Notch. Indeed, Notch removal from the cell surface and its targeting to the lysosome for degradation is one way in which Notch activity is downregulated since it limits receptor exposure to ligand. In contrast, Notch-signaling capacity is maintained through repeated rounds of receptor recycling and redelivery of Notch to the cell surface from endosomal stores. This review discusses the molecular mechanisms by which Notch transit through the endosome is controlled and how various intracellular sorting decisions are thought to impact signaling activity.
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29
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Jiang Y, Rigoglioso A, Peterhoff CM, Pawlik M, Sato Y, Bleiwas C, Stavrides P, Smiley JF, Ginsberg SD, Mathews PM, Levy E, Nixon RA. Partial BACE1 reduction in a Down syndrome mouse model blocks Alzheimer-related endosomal anomalies and cholinergic neurodegeneration: role of APP-CTF. Neurobiol Aging 2015; 39:90-8. [PMID: 26923405 DOI: 10.1016/j.neurobiolaging.2015.11.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 11/17/2015] [Accepted: 11/23/2015] [Indexed: 11/30/2022]
Abstract
β-amyloid precursor protein (APP) and amyloid beta peptide (Aβ) are strongly implicated in Alzheimer's disease (AD) pathogenesis, although recent evidence has linked APP-βCTF generated by BACE1 (β-APP cleaving enzyme 1) to the development of endocytic abnormalities and cholinergic neurodegeneration in early AD. We show that partial BACE1 genetic reduction prevents these AD-related pathological features in the Ts2 mouse model of Down syndrome. Partially reducing BACE1 by deleting one BACE1 allele blocked development of age-related endosome enlargement in the medial septal nucleus, cerebral cortex, and hippocampus and loss of choline acetyltransferase (ChAT)-positive medial septal nucleus neurons. BACE1 reduction normalized APP-βCTF elevation but did not alter Aβ40 and Aβ42 peptide levels in brain, supporting a critical role in vivo for APP-βCTF in the development of these abnormalities. Although ameliorative effects of BACE1 inhibition on β-amyloidosis and synaptic proteins levels have been previously noted in AD mouse models, our results highlight the additional potential value of BACE1 modulation in therapeutic targeting of endocytic dysfunction and cholinergic neurodegeneration in Down syndrome and AD.
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Affiliation(s)
- Ying Jiang
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Medical Center, New York, NY, USA
| | - Andrew Rigoglioso
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | | | - Monika Pawlik
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | - Yutaka Sato
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | - Cynthia Bleiwas
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | - Philip Stavrides
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | - John F Smiley
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Medical Center, New York, NY, USA
| | - Stephen D Ginsberg
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Medical Center, New York, NY, USA; Department of Neuroscience & Physiology, NYU Langone Medical Center, New York, NY, USA
| | - Paul M Mathews
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Medical Center, New York, NY, USA
| | - Efrat Levy
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Medical Center, New York, NY, USA; Department of Biochemistry and Molecular Pharmacology, NYU Langone Medical Center, New York, NY, USA
| | - Ralph A Nixon
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Medical Center, New York, NY, USA; Department of Cell Biology, NYU Langone Medical Center, New York, NY, USA.
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30
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Chapman G, Major JA, Iyer K, James AC, Pursglove SE, Moreau JLM, Dunwoodie SL. Notch1 endocytosis is induced by ligand and is required for signal transduction. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:166-77. [PMID: 26522918 DOI: 10.1016/j.bbamcr.2015.10.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 10/27/2015] [Accepted: 10/28/2015] [Indexed: 01/20/2023]
Abstract
The Notch signalling pathway is widely utilised during embryogenesis in situations where cell-cell interactions are important for cell fate specification and differentiation. DSL ligand endocytosis into the ligand-expressing cell is an important aspect of Notch signalling because it is thought to supply the force needed to separate the Notch heterodimer to initiate signal transduction. A functional role for receptor endocytosis during Notch signal transduction is more controversial. Here we have used live-cell imaging to examine trafficking of the Notch1 receptor in response to ligand binding. Contact with cells expressing ligands induced internalisation and intracellular trafficking of Notch1. Notch1 endocytosis was accompanied by transendocytosis of ligand into the Notch1-expressing signal-receiving cell. Ligand caused Notch1 endocytosis into SARA-positive endosomes in a manner dependent on clathrin and dynamin function. Moreover, inhibition of endocytosis in the receptor-expressing cell impaired ligand-induced Notch1 signalling. Our findings resolve conflicting observations from mammalian and Drosophila studies by demonstrating that ligand-dependent activation of Notch1 signalling requires receptor endocytosis. Endocytosis of Notch1 may provide a force on the ligand:receptor complex that is important for potent signal transduction.
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Affiliation(s)
- G Chapman
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Sydney, Australia; St. Vincent's Clinical School, University of New South Wales, Sydney, Australia.
| | - J A Major
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Sydney, Australia
| | - K Iyer
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Sydney, Australia
| | - A C James
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Sydney, Australia
| | - S E Pursglove
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Sydney, Australia
| | - J L M Moreau
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Sydney, Australia
| | - S L Dunwoodie
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Sydney, Australia; St. Vincent's Clinical School, University of New South Wales, Sydney, Australia; School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
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31
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van der Kant R, Goldstein LSB. Cellular functions of the amyloid precursor protein from development to dementia. Dev Cell 2015; 32:502-15. [PMID: 25710536 DOI: 10.1016/j.devcel.2015.01.022] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Amyloid precursor protein (APP) is a key player in Alzheimer's disease (AD). The Aβ fragments of APP are the major constituent of AD-associated amyloid plaques, and mutations or duplications of the gene coding for APP can cause familial AD. Here we review the roles of APP in neuronal development, signaling, intracellular transport, and other aspects of neuronal homeostasis. We suggest that APP acts as a signaling nexus that transduces information about a range of extracellular conditions, including neuronal damage, to induction of intracellular signaling events. Subtle disruptions of APP signaling functions may be major contributors to AD-causing neuronal dysfunction.
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Affiliation(s)
- Rik van der Kant
- Department of Cellular and Molecular Medicine, University of California-San Diego, La Jolla, CA 92093, USA.
| | - Lawrence S B Goldstein
- Department of Cellular and Molecular Medicine, University of California-San Diego, La Jolla, CA 92093, USA.
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32
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Weissmiller AM, Natera-Naranjo O, Reyna SM, Pearn ML, Zhao X, Nguyen P, Cheng S, Goldstein LSB, Tanzi RE, Wagner SL, Mobley WC, Wu C. A γ-secretase inhibitor, but not a γ-secretase modulator, induced defects in BDNF axonal trafficking and signaling: evidence for a role for APP. PLoS One 2015; 10:e0118379. [PMID: 25710492 PMCID: PMC4339551 DOI: 10.1371/journal.pone.0118379] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 01/14/2015] [Indexed: 11/19/2022] Open
Abstract
Clues to Alzheimer disease (AD) pathogenesis come from a variety of different sources including studies of clinical and neuropathological features, biomarkers, genomics and animal and cellular models. An important role for amyloid precursor protein (APP) and its processing has emerged and considerable interest has been directed at the hypothesis that Aβ peptides induce changes central to pathogenesis. Accordingly, molecules that reduce the levels of Aβ peptides have been discovered such as γ-secretase inhibitors (GSIs) and modulators (GSMs). GSIs and GSMs reduce Aβ levels through very different mechanisms. However, GSIs, but not GSMs, markedly increase the levels of APP CTFs that are increasingly viewed as disrupting neuronal function. Here, we evaluated the effects of GSIs and GSMs on a number of neuronal phenotypes possibly relevant to their use in treatment of AD. We report that GSI disrupted retrograde axonal trafficking of brain-derived neurotrophic factor (BDNF), suppressed BDNF-induced downstream signaling pathways and induced changes in the distribution within neuronal processes of mitochondria and synaptic vesicles. In contrast, treatment with a novel class of GSMs had no significant effect on these measures. Since knockdown of APP by specific siRNA prevented GSI-induced changes in BDNF axonal trafficking and signaling, we concluded that GSI effects on APP processing were responsible, at least in part, for BDNF trafficking and signaling deficits. Our findings argue that with respect to anti-amyloid treatments, even an APP-specific GSI may have deleterious effects and GSMs may serve as a better alternative.
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Affiliation(s)
- April M. Weissmiller
- Department of Neurosciences, University of California San Diego, San Diego, California, United States of America
| | - Orlangie Natera-Naranjo
- Department of Neurosciences, University of California San Diego, San Diego, California, United States of America
| | - Sol M. Reyna
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, California, United States of America
| | - Matthew L. Pearn
- Department of Anesthesiology, University of California San Diego, San Diego, California, United States of America
- V.A. San Diego Healthcare System, San Diego, California, United States of America
| | - Xiaobei Zhao
- Department of Neurosciences, University of California San Diego, San Diego, California, United States of America
| | - Phuong Nguyen
- Department of Neurosciences, University of California San Diego, San Diego, California, United States of America
| | - Soan Cheng
- Department of Neurosciences, University of California San Diego, San Diego, California, United States of America
| | - Lawrence S. B. Goldstein
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, California, United States of America
| | - Rudolph E. Tanzi
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Steven L. Wagner
- Department of Neurosciences, University of California San Diego, San Diego, California, United States of America
| | - William C. Mobley
- Department of Neurosciences, University of California San Diego, San Diego, California, United States of America
| | - Chengbiao Wu
- Department of Neurosciences, University of California San Diego, San Diego, California, United States of America
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33
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Niederst ED, Reyna SM, Goldstein LSB. Axonal amyloid precursor protein and its fragments undergo somatodendritic endocytosis and processing. Mol Biol Cell 2014; 26:205-17. [PMID: 25392299 PMCID: PMC4294669 DOI: 10.1091/mbc.e14-06-1049] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In mouse and human neurons, axonally secreted amyloid precursor protein (APP) fragments are processed in the cell body before being sorted into the axon in a process that requires endocytosis for the processing, but not axonal delivery, of APP. Deposition of potentially neurotoxic Aβ fragments derived from amyloid precursor protein (APP) at synapses may be a key contributor to Alzheimer's disease. However, the location(s) of proteolytic processing and subsequent secretion of APP fragments from highly compartmentalized, euploid neurons that express APP and processing enzymes at normal levels is not well understood. To probe the behavior of endogenous APP, particularly in human neurons, we developed a system using neurons differentiated from human embryonic stem cells, cultured in microfluidic devices, to enable direct biochemical measurements from axons. Using human or mouse neurons in these devices, we measured levels of Aβ, sAPPα, and sAPPβ secreted solely from axons. We found that a majority of the fragments secreted from axons were processed in the soma, and many were dependent on somatic endocytosis for axonal secretion. We also observed that APP and the β-site APP cleaving enzyme were, for the most part, not dependent on endocytosis for axonal entry. These data establish that axonal entry and secretion of APP and its proteolytic processing products traverse different pathways in the somatodendritic compartment before axonal entry.
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Affiliation(s)
- Emily D Niederst
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Sol M Reyna
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Lawrence S B Goldstein
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
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34
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Kanatsu K, Morohashi Y, Suzuki M, Kuroda H, Watanabe T, Tomita T, Iwatsubo T. Decreased CALM expression reduces Aβ42 to total Aβ ratio through clathrin-mediated endocytosis of γ-secretase. Nat Commun 2014; 5:3386. [PMID: 24577224 DOI: 10.1038/ncomms4386] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 02/05/2014] [Indexed: 01/08/2023] Open
Abstract
A body of evidence suggests that aberrant metabolism of amyloid-β peptide (Aβ) underlies the aetiology of Alzheimer disease (AD). Recently, a single-nucleotide polymorphism in phosphatidylinositol binding clathrin assembly protein (PICALM/CALM) gene, which encodes a protein implicated in the clathrin-mediated endocytosis, was identified as a genetic protective factor for AD, although its mechanistic details have little been explored. Here we show that loss of CALM leads to the selective decrease in the production ratio of the pathogenic Aβ species, Aβ42. Active form of γ-secretase is constitutively endocytosed via the clathrin-mediated pathway in a CALM dependent manner. Alteration in the rate of clathrin-mediated endocytosis of γ-secretase causes a shift in its steady-state localization, which consequently impacts on the production ratio of Aβ42. Our study identifies CALM as an endogenous modulator of γ-secretase activity by regulating its endocytosis and also as an excellent target for Aβ42-lowering AD therapeutics.
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Affiliation(s)
- Kunihiko Kanatsu
- 1] Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan [2]
| | - Yuichi Morohashi
- 1] Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan [2] Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 113-0033, Japan [3]
| | - Mai Suzuki
- Department of Biological Science, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan
| | - Hiromasa Kuroda
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Toshio Watanabe
- Department of Biological Science, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan
| | - Taisuke Tomita
- 1] Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan [2] Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 113-0033, Japan
| | - Takeshi Iwatsubo
- 1] Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan [2] Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 113-0033, Japan [3] Department of Neuropathology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
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35
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Morel E, Chamoun Z, Lasiecka ZM, Chan RB, Williamson RL, Vetanovetz C, Dall'Armi C, Simoes S, Point Du Jour KS, McCabe BD, Small SA, Di Paolo G. Phosphatidylinositol-3-phosphate regulates sorting and processing of amyloid precursor protein through the endosomal system. Nat Commun 2014; 4:2250. [PMID: 23907271 DOI: 10.1038/ncomms3250] [Citation(s) in RCA: 166] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 07/03/2013] [Indexed: 01/24/2023] Open
Abstract
Defects in endosomal sorting have been implicated in Alzheimer's disease. Endosomal traffic is largely controlled by phosphatidylinositol-3-phosphate, a phosphoinositide synthesized primarily by lipid kinase Vps34. Here we show that phosphatidylinositol-3-phosphate is selectively deficient in brain tissue from humans with Alzheimer's disease and Alzheimer's disease mouse models. Silencing Vps34 causes an enlargement of neuronal endosomes, enhances the amyloidogenic processing of amyloid precursor protein in these organelles and reduces amyloid precursor protein sorting to intraluminal vesicles. This trafficking phenotype is recapitulated by silencing components of the ESCRT (Endosomal Sorting Complex Required for Transport) pathway, including the phosphatidylinositol-3-phosphate effector Hrs and Tsg101. Amyloid precursor protein is ubiquitinated, and interfering with this process by targeted mutagenesis alters sorting of amyloid precursor protein to the intraluminal vesicles of endosomes and enhances amyloid-beta peptide generation. In addition to establishing phosphatidylinositol-3-phosphate deficiency as a contributing factor in Alzheimer's disease, these results clarify the mechanisms of amyloid precursor protein trafficking through the endosomal system in normal and pathological states.
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Affiliation(s)
- Etienne Morel
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA
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36
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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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37
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Udayar V, Buggia-Prévot V, Guerreiro RL, Siegel G, Rambabu N, Soohoo AL, Ponnusamy M, Siegenthaler B, Bali J, Simons M, Ries J, Puthenveedu MA, Hardy J, Thinakaran G, Rajendran L. A paired RNAi and RabGAP overexpression screen identifies Rab11 as a regulator of β-amyloid production. Cell Rep 2013; 5:1536-51. [PMID: 24373285 PMCID: PMC4004174 DOI: 10.1016/j.celrep.2013.12.005] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 11/07/2013] [Accepted: 12/03/2013] [Indexed: 12/16/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by cerebral deposition of β-amyloid (Aβ) peptides, which are generated from amyloid precursor protein (APP) by β- and γ-secretases. APP and the secretases are membrane associated, but whether membrane trafficking controls Aβ levels is unclear. Here, we performed an RNAi screen of all human Rab-GTPases, which regulate membrane trafficking, complemented with a Rab-GTPase-activating protein screen, and present a road map of the membrane-trafficking events regulating Aβ production. We identify Rab11 and Rab3 as key players. Although retromers and retromer-associated proteins control APP recycling, we show that Rab11 controlled β-secretase endosomal recycling to the plasma membrane and thus affected Aβ production. Exome sequencing revealed a significant genetic association of Rab11A with late-onset AD, and network analysis identified Rab11A and Rab11B as components of the late-onset AD risk network, suggesting a causal link between Rab11 and AD. Our results reveal trafficking pathways that regulate Aβ levels and show how systems biology approaches can unravel the molecular complexity underlying AD.
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Affiliation(s)
- Vinod Udayar
- Systems and Cell Biology of Neurodegeneration, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland; Division of Psychiatry Research, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland; Graduate Program of the Zurich Neuroscience Center, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland; Erasmus Mundus Joint Doctorate Program, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland
| | - Virginie Buggia-Prévot
- Departments of Neurobiology, Neurology and Pathology, The University of Chicago, Chicago, IL 60637, USA
| | - Rita L Guerreiro
- Alzheimer's Exome Sequencing Group, University College London, London WC1E 6BT, UK; Reta Lila Weston Research Laboratories, Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3BG, UK
| | - Gabriele Siegel
- Systems and Cell Biology of Neurodegeneration, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland; Division of Psychiatry Research, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland
| | - Naresh Rambabu
- Raise.Rural Foundation for Promoting Research Awareness in Student Environment in Rural India, 60045 Chennai, India
| | - Amanda L Soohoo
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Moorthi Ponnusamy
- Raise.Rural Foundation for Promoting Research Awareness in Student Environment in Rural India, 60045 Chennai, India
| | - Barbara Siegenthaler
- Systems and Cell Biology of Neurodegeneration, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland; Division of Psychiatry Research, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland
| | - Jitin Bali
- Systems and Cell Biology of Neurodegeneration, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland; Division of Psychiatry Research, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland; Graduate Program of the Zurich Neuroscience Center, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland
| | - Mikael Simons
- Department of Neurology, University of Göttingen, 37075 Göttingen, Germany; Max-Planck Institute for Experimental Medicine, 37075 Göttingen, Germany
| | - Jonas Ries
- Cell Biology and Biophysics, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | | | - John Hardy
- Alzheimer's Exome Sequencing Group, University College London, London WC1E 6BT, UK; Reta Lila Weston Research Laboratories, Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3BG, UK
| | - Gopal Thinakaran
- Departments of Neurobiology, Neurology and Pathology, The University of Chicago, Chicago, IL 60637, USA
| | - Lawrence Rajendran
- Systems and Cell Biology of Neurodegeneration, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland; Division of Psychiatry Research, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland; Graduate Program of the Zurich Neuroscience Center, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland; Graduate Program of the Zurich Center for Integrative Human Physiology, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland.
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38
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Bustamante HA, Rivera-Dictter A, Cavieres VA, Muñoz VC, González A, Lin Y, Mardones GA, Burgos PV. Turnover of C99 is controlled by a crosstalk between ERAD and ubiquitin-independent lysosomal degradation in human neuroglioma cells. PLoS One 2013; 8:e83096. [PMID: 24376644 PMCID: PMC3869756 DOI: 10.1371/journal.pone.0083096] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 11/06/2013] [Indexed: 12/28/2022] Open
Abstract
Alzheimer’s disease (AD) is characterized by the buildup of amyloid-β peptides (Aβ) aggregates derived from proteolytic processing of the β-amyloid precursor protein (APP). Amyloidogenic cleavage of APP by β-secretase/BACE1 generates the C-terminal fragment C99/CTFβ that can be subsequently cleaved by γ-secretase to produce Aβ. Growing evidence indicates that high levels of C99/CTFβ are determinant for AD. Although it has been postulated that γ-secretase-independent pathways must control C99/CTFβ levels, the contribution of organelles with degradative functions, such as the endoplasmic reticulum (ER) or lysosomes, is unclear. In this report, we investigated the turnover and amyloidogenic processing of C99/CTFβ in human H4 neuroglioma cells, and found that C99/CTFβ is localized at the Golgi apparatus in contrast to APP, which is mostly found in endosomes. Conditions that localized C99/CTFβ to the ER resulted in its degradation in a proteasome-dependent manner that first required polyubiquitination, consistent with an active role of the ER associated degradation (ERAD) in this process. Furthermore, when proteasomal activity was inhibited C99/CTFβ was degraded in a chloroquine (CQ)-sensitive compartment, implicating lysosomes as alternative sites for its degradation. Our results highlight a crosstalk between degradation pathways within the ER and lysosomes to avoid protein accumulation and toxicity.
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Affiliation(s)
- Hianara A. Bustamante
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Andrés Rivera-Dictter
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Viviana A. Cavieres
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Vanessa C. Muñoz
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Alexis González
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Yimo Lin
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Gonzalo A. Mardones
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Patricia V. Burgos
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
- * E-mail:
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39
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Zhang X, Song W. The role of APP and BACE1 trafficking in APP processing and amyloid-β generation. ALZHEIMERS RESEARCH & THERAPY 2013; 5:46. [PMID: 24103387 PMCID: PMC3978418 DOI: 10.1186/alzrt211] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neuritic plaques in the brain are a major neuropathological hallmark of Alzheimer’s disease. They are formed by the deposition and aggregation of extracellular amyloid-β protein (Aβ). Aβ is derived from the sequential cleavage of amyloid-β precursor protein (APP) by β-secretase and γ-secretase. β-Site APP cleaving enzyme 1 (BACE1) functions as the primary, if not sole, β-secretase in vivo and is essential for Aβ production. Regulation of APP processing is a major focus of research into AD pathogenesis. The trafficking systems of APP and its cleavage enzymes are complex. Transporting APP and secretases into the same subcellular organelles facilitates their interaction and favors APP processing. The role of APP and BACE1 trafficking in the amyloidgenic pathway and the underlying mechanisms for Aβ production are discussed in this review. In addition, the distinct mechanisms of amino- and carboxy-terminal Aβ generation are reviewed.
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Affiliation(s)
- Xiaojie Zhang
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, 2255 Wesbrook Mall, Vancouver BC V6T 1Z3, Canada
| | - Weihong Song
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, 2255 Wesbrook Mall, Vancouver BC V6T 1Z3, Canada
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40
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Smolarkiewicz M, Skrzypczak T, Wojtaszek P. The very many faces of presenilins and the γ-secretase complex. PROTOPLASMA 2013; 250:997-1011. [PMID: 23504135 PMCID: PMC3788181 DOI: 10.1007/s00709-013-0494-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 03/01/2013] [Indexed: 05/02/2023]
Abstract
Presenilin is a central, catalytic component of the γ-secretase complex which conducts intramembrane cleavage of various protein substrates. Although identified and mainly studied through its role in the development of amyloid plaques in Alzheimer disease, γ-secretase has many other important functions. The complex seems to be evolutionary conserved throughout the Metazoa, but recent findings in plants and Dictyostelium discoideum as well as in archeons suggest that its evolution and functions might be much more diversified than previously expected. In this review, a selective survey of the multitude of functions of presenilins and the γ-secretase complex is presented. Following a brief overview of γ-secretase structure, assembly and maturation, three functional aspects are analyzed: (1) the role of γ-secretase in autophagy and phagocytosis; (2) involvement of the complex in signaling related to endocytosis; and (3) control of calcium fluxes by presenilins.
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Affiliation(s)
- Michalina Smolarkiewicz
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Tomasz Skrzypczak
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Przemysław Wojtaszek
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
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41
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Armato U, Chiarini A, Chakravarthy B, Chioffi F, Pacchiana R, Colarusso E, Whitfield JF, Dal Prà I. Calcium-sensing receptor antagonist (calcilytic) NPS 2143 specifically blocks the increased secretion of endogenous Aβ42 prompted by exogenous fibrillary or soluble Aβ25-35 in human cortical astrocytes and neurons-therapeutic relevance to Alzheimer's disease. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1832:1634-52. [PMID: 23628734 DOI: 10.1016/j.bbadis.2013.04.020] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 03/28/2013] [Accepted: 04/18/2013] [Indexed: 11/17/2022]
Abstract
The "amyloid-β (Aβ) hypothesis" posits that accumulating Aβ peptides (Aβs) produced by neurons cause Alzheimer's disease (AD). However, the Aβs contribution by the more numerous astrocytes remains undetermined. Previously we showed that fibrillar (f)Aβ25-35, an Aβ42 proxy, evokes a surplus endogenous Aβ42 production/accumulation in cortical adult human astrocytes. Here, by using immunocytochemistry, immunoblotting, enzymatic assays, and highly sensitive sandwich ELISA kits, we investigated the effects of fAβ25-35 and soluble (s)Aβ25-35 on Aβ42 and Aβ40 accumulation/secretion by human cortical astrocytes and HCN-1A neurons and, since the calcium-sensing receptor (CaSR) binds Aβs, their modulation by NPS 2143, a CaSR allosteric antagonist (calcilytic). The fAβ25-35-exposed astrocytes and surviving neurons produced, accumulated, and secreted increased amounts of Aβ42, while Aβ40 also accrued but its secretion was unchanged. Accordingly, secreted Aβ42/Aβ40 ratio values rose for astrocytes and neurons. While slightly enhancing Aβ40 secretion by fAβ25-35-treated astrocytes, NPS 2143 specifically suppressed the fAβ25-35-elicited surges of endogenous Aβ42 secretion by astrocytes and neurons. Therefore, NPS 2143 addition always kept Aβ42/Aβ40 values to baseline or lower levels. Mechanistically, NPS 2143 decreased total CaSR protein complement, transiently raised proteasomal chymotrypsin activity, and blocked excess NO production without affecting the ongoing increases in BACE1/β-secretase and γ-secretase activity in fAβ25-35-treated astrocytes. Compared to fAβ25-35, sAβ25-35 also stimulated Aβ42 secretion by astrocytes and neurons and NPS 2143 specifically and wholly suppressed this effect. Therefore, since NPS 2143 thwarts any Aβ/CaSR-induced surplus secretion of endogenous Aβ42 and hence further vicious cycles of Aβ self-induction/secretion/spreading, calcilytics might effectively prevent/stop the progression to full-blown AD.
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Affiliation(s)
- Ubaldo Armato
- Department of Life and Reproduction Sciences, University of Verona Medical School, Verona, Italy.
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42
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Morohashi Y, Tomita T. Protein trafficking and maturation regulate intramembrane proteolysis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2855-61. [PMID: 23770323 DOI: 10.1016/j.bbamem.2013.06.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Revised: 05/04/2013] [Accepted: 06/03/2013] [Indexed: 12/30/2022]
Abstract
Intramembrane-cleaving proteases (I-CLiPs) are membrane embedded proteolytic enzymes. All substrates identified so far are also membrane proteins, involving a number of critical cellular signaling as well as human diseases. After synthesis and assembly at the endoplasmic reticulum, membrane proteins are exported to the Golgi apparatus and transported to their sites of action. A number of studies have revealed the importance of the intracellular membrane trafficking in i-CLiP-mediated intramembrane proteolysis, not only for limiting the unnecessary encounter between i-CLiPs and their substrate but also for their cleavage site preference. In this review, we will discuss recent advances in our understanding of how each i-CLiP proteolysis is regulated by intracellular vesicle trafficking. This article is part of a Special Issue entitled: Intramembrane Proteases.
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Affiliation(s)
- Yuichi Morohashi
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
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43
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Viswanathan J, Haapasalo A, Kurkinen KMA, Natunen T, Mäkinen P, Bertram L, Soininen H, Tanzi RE, Hiltunen M. Ubiquilin-1 Modulates γ-Secretase-Mediated ε-Site Cleavage in Neuronal Cells. Biochemistry 2013; 52:3899-912. [DOI: 10.1021/bi400138p] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jayashree Viswanathan
- Institute of Clinical Medicine-Neurology, University of Eastern Finland, and Department of Neurology, Kuopio University Hospital, Kuopio, Finland
| | - Annakaisa Haapasalo
- Institute of Clinical Medicine-Neurology, University of Eastern Finland, and Department of Neurology, Kuopio University Hospital, Kuopio, Finland
| | - Kaisa M. A. Kurkinen
- Institute of Clinical Medicine-Neurology, University of Eastern Finland, and Department of Neurology, Kuopio University Hospital, Kuopio, Finland
| | - Teemu Natunen
- Institute of Clinical Medicine-Neurology, University of Eastern Finland, and Department of Neurology, Kuopio University Hospital, Kuopio, Finland
| | - Petra Mäkinen
- Institute of Clinical Medicine-Neurology, University of Eastern Finland, and Department of Neurology, Kuopio University Hospital, Kuopio, Finland
| | - Lars Bertram
- Department of Vertebrate Genomics, Max-Planck-Institute for Molecular Genetics, Berlin,
Germany
| | - Hilkka Soininen
- Institute of Clinical Medicine-Neurology, University of Eastern Finland, and Department of Neurology, Kuopio University Hospital, Kuopio, Finland
| | - Rudolph E. Tanzi
- Genetics and Aging
Research Unit, Massachusetts General Hospital/Harvard Medical School, Charlestown, Massachusetts 02129, United
States
| | - Mikko Hiltunen
- Institute of Clinical Medicine-Neurology, University of Eastern Finland, and Department of Neurology, Kuopio University Hospital, Kuopio, Finland
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44
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Ubiquitinations in the notch signaling pathway. Int J Mol Sci 2013; 14:6359-81. [PMID: 23519106 PMCID: PMC3634445 DOI: 10.3390/ijms14036359] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/11/2013] [Accepted: 03/14/2013] [Indexed: 12/22/2022] Open
Abstract
The very conserved Notch pathway is used iteratively during development and adulthood to regulate cell fates. Notch activation relies on interactions between neighboring cells, through the binding of Notch receptors to their ligands, both transmembrane molecules. This inter-cellular contact initiates a cascade of events eventually transforming the cell surface receptor into a nuclear factor acting on the transcription of specific target genes. This review highlights how the various processes undergone by Notch receptors and ligands that regulate the pathway are linked to ubiquitination events.
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45
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Liu X, Zhao X, Zeng X, Bossers K, Swaab DF, Zhao J, Pei G. β-arrestin1 regulates γ-secretase complex assembly and modulates amyloid-β pathology. Cell Res 2012. [PMID: 23208420 PMCID: PMC3587707 DOI: 10.1038/cr.2012.167] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive and complex neurodegenerative disease in which the γ-secretase-mediated amyloid-β (Aβ) pathology plays an important role. We found that a multifunctional protein, β-arrestin1, facilitated the formation of NCT/APH-1 (anterior pharynx-defective phenotype 1) precomplex and mature γ-secretase complex through its functional interaction with APH-1. Deficiency of β-arrestin1 or inhibition of binding of β-arrestin1 with APH-1 by small peptides reduced Aβ production without affecting Notch processing. Genetic ablation of β-arrestin1 diminished Aβ pathology and behavioral deficits in transgenic AD mice. Moreover, in brains of sporadic AD patients and transgenic AD mice, the expression of β-arrestin1 was upregulated and correlated well with neuropathological severity and senile Aβ plaques. Thus, our study identifies a regulatory mechanism underlying both γ-secretase assembly and AD pathogenesis, and indicates that specific reduction of Aβ pathology can be achieved by regulation of the γ-secretase assembly.
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Affiliation(s)
- Xiaosong Liu
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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46
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Zheng L, Saunders CA, Sorensen EB, Waxmonsky NC, Conner SD. Notch signaling from the endosome requires a conserved dileucine motif. Mol Biol Cell 2012; 24:297-307. [PMID: 23171551 PMCID: PMC3564540 DOI: 10.1091/mbc.e12-02-0081] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Notch signaling is reliant on γ-secretase–mediated processing, although the subcellular location where it cleaves Notch to initiate signaling remains unresolved. Findings here support a model in which Notch signaling in mammalian systems is initiated from either the plasma membrane or lysosome, but not the early endosome. Notch signaling is reliant on γ-secretase–mediated processing, although the subcellular location where γ-secretase cleaves Notch to initiate signaling remains unresolved. Accumulating evidence demonstrates that Notch signaling is modulated by endocytosis and endosomal transport. In this study, we investigated the relationship between Notch transport itinerary and signaling capacity. In doing so, we discovered a highly conserved dileucine sorting signal encoded within the cytoplasmic tail that directs Notch to the limiting membrane of the lysosome for signaling. Mutating the dileucine motif led to receptor accumulation in cation-dependent mannose-phosphate receptor–positive tubular early endosomes and a reduction in Notch signaling capacity. Moreover, truncated receptor forms that mimic activated Notch were readily cleaved by γ-secretase within the endosome; however, the cleavage product was proteasome-sensitive and failed to contribute to robust signaling. Collectively these results indicate that Notch signaling from the lysosome limiting membrane is conserved and that receptor targeting to this compartment is an active process. Moreover, the data support a model in which Notch signaling in mammalian systems is initiated from either the plasma membrane or lysosome, but not the early endosome.
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Affiliation(s)
- Li Zheng
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
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47
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Rodrigues EM, Weissmiller AM, Goldstein LSB. Enhanced β-secretase processing alters APP axonal transport and leads to axonal defects. Hum Mol Genet 2012; 21:4587-601. [PMID: 22843498 DOI: 10.1093/hmg/dds297] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease pathologically characterized by amyloid plaques and neurofibrillary tangles in the brain. Before these hallmark features appear, signs of axonal transport defects develop, though the initiating events are not clear. Enhanced amyloidogenic processing of amyloid precursor protein (APP) plays an integral role in AD pathogenesis, and previous work suggests that both the Aβ region and the C-terminal fragments (CTFs) of APP can cause transport defects. However, it remains unknown if APP processing affects the axonal transport of APP itself, and whether increased APP processing is sufficient to promote axonal dystrophy. We tested the hypothesis that β-secretase cleavage site mutations of APP alter APP axonal transport directly. We found that the enhanced β-secretase cleavage reduces the anterograde axonal transport of APP, while inhibited β-cleavage stimulates APP anterograde axonal transport. Transport behavior of APP after treatment with β- or γ-secretase inhibitors suggests that the amount of β-secretase cleaved CTFs (βCTFs) of APP underlies these transport differences. Consistent with these findings, βCTFs have reduced anterograde axonal transport compared with full-length, wild-type APP. Finally, a gene-targeted mouse with familial AD (FAD) Swedish mutations to APP, which enhance the β-cleavage of APP, develops axonal dystrophy in the absence of mutant protein overexpression, amyloid plaque deposition and synaptic degradation. These results suggest that the enhanced β-secretase processing of APP can directly impair the anterograde axonal transport of APP and are sufficient to lead to axonal defects in vivo.
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Affiliation(s)
- Elizabeth M Rodrigues
- Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, USA
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Cuartero Y, Mellado M, Capell A, Álvarez-Dolado M, Verges M. Retromer Regulates Postendocytic Sorting of β-Secretase in Polarized Madin-Darby Canine Kidney Cells. Traffic 2012; 13:1393-410. [DOI: 10.1111/j.1600-0854.2012.01392.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 06/28/2012] [Accepted: 07/03/2012] [Indexed: 01/24/2023]
Affiliation(s)
- Yasmina Cuartero
- Laboratory of Epithelial Cell Biology; Centro de Investigación Príncipe Felipe; Valencia; Spain
| | - Maravillas Mellado
- Laboratory of Epithelial Cell Biology; Centro de Investigación Príncipe Felipe; Valencia; Spain
| | - Anja Capell
- German Center for Neurodegenerative Diseases & Adolf Butenandt Institute - Biochemistry; Ludwig Maximilians University; Munich; Germany
| | - Manuel Álvarez-Dolado
- Department of Cell Therapy and Regenerative Medicine; Andalusian Center for Molecular Biology and Regenerative Medicine; Seville; Spain
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Viana RJS, Nunes AF, Rodrigues CMP. Endoplasmic reticulum enrollment in Alzheimer's disease. Mol Neurobiol 2012; 46:522-34. [PMID: 22815194 DOI: 10.1007/s12035-012-8301-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 07/05/2012] [Indexed: 12/26/2022]
Abstract
Alzheimer's disease (AD) poses a huge challenge for society and health care worldwide as molecular pathogenesis of the disease is poorly understood and curative treatment does not exist. The mechanisms leading to accelerated neuronal cell death in AD are still largely unknown, but accumulation of misfolded disease-specific proteins has been identified as potentially involved. In the present review, we describe the essential role of endoplasmic reticulum (ER) in AD. Despite the function that mitochondria may play as the central major player in the apoptotic process, accumulating evidence highlights ER as a critical organelle in AD. Stress that impairs ER physiology leads to accumulation of unfolded or misfolded proteins, such as amyloid β (Aβ) peptide, the major component of amyloid plaques. In an attempt to ameliorate the accumulation of unfolded proteins, ER stress triggers a protective cellular mechanism, which includes the unfolded protein response (UPR). However, when activation of the UPR is severe or prolonged enough, the final cellular outcome is pathologic apoptotic cell death. Distinct pathways can be activated in this process, involving stress sensors such as the JNK pathway or ER chaperones such as Bip/GRP94, stress modulators such as Bcl-2 family proteins, or even stress effectors such as caspase-12. Here, we detail the involvement of the ER and associated stress pathways in AD and discuss potential therapeutic strategies targeting ER stress.
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Affiliation(s)
- Ricardo J S Viana
- Research Institute for Medicines and Pharmaceutical Sciences, University of Lisbon, Lisbon 1649-003, Portugal
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Rajagopal C, Mains RE, Eipper BA. Signaling from the secretory granule to the nucleus. Crit Rev Biochem Mol Biol 2012; 47:391-406. [PMID: 22681236 DOI: 10.3109/10409238.2012.694845] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Neurons and endocrine cells use a complex array of signaling molecules to communicate with each other and with various targets. The majority of these signaling molecules are stored in specialized organelles awaiting release on demand: 40-60 nm vesicles carry conventional or small molecule neurotransmitters, and 200-400 nm granules contain bioactive peptides. The supply of small molecule neurotransmitters is tightly regulated by local feedback of synthetic rates and transport processes at sites of release. The larger granules that contain bioactive peptides present the secretory cell with special challenges, as the peptide precursors are inserted into the lumen of the secretory pathway in the cell soma and undergo biosynthetic processing while being transported to distant sites for eventual secretion. One solution to this dilemma in information handling has been to employ proteolytic cleavage of secretory granule membrane proteins to produce cytosolic fragments that can signal to the nucleus, affecting gene expression. The use of regulated intramembrane proteolysis to signal from secretory granules to the nucleus is compared to its much better understood role in relaying information from the endoplasmic reticulum by SREBP and ATF6 and from the plasma membrane by cadherins, Notch and ErbB4.
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Affiliation(s)
- Chitra Rajagopal
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, CT, USA
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