51
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Guo Y, Wang Q, Chen S, Xu C. Functions of amyloid precursor protein in metabolic diseases. Metabolism 2021; 115:154454. [PMID: 33248065 DOI: 10.1016/j.metabol.2020.154454] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 11/02/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023]
Abstract
Amyloid precursor protein (APP) is a transmembrane precursor protein that is widely expressed in the central nervous system and peripheral tissues in the liver and pancreas, adipose tissue, and myotubes. APP can be cleaved by proteases in two different ways to produce a variety of short peptides, each with different physiological properties and functions. APP peptides generated by non-amyloidogenic processing can positively influence metabolism, while the peptides produced by amyloidogenic processing have the opposite effects. Here, we summarize the regulatory effects of APP and its cleavage peptides on metabolism in the central nervous system and peripheral tissues. In addition, abnormal expression and function of APP and APP-derived peptides are associated with metabolic diseases, such as type 2 diabetes, obesity, non-alcoholic fatty liver disease, and cardiovascular disease, and cancers. Pharmacological intervention of APP function or reduction of the production of peptides derived from amyloidogenic processing may be effective strategies for the prevention and treatment of Alzheimer's disease, and they may also provide new guidance for the treatment of metabolic diseases.
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Affiliation(s)
- Yanjun Guo
- Department of Gastroenterology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Qinqiu Wang
- Department of Gastroenterology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Shenghui Chen
- Department of Gastroenterology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Chengfu Xu
- Department of Gastroenterology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China.
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52
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Jiang S, Liu M, Tantai W, Xu Q, Zou X, Ma F, Zhang CY. Aptamer-mediated rolling circle amplification for label-free and sensitive detection of histone acetyltransferase activity. Chem Commun (Camb) 2021; 57:2041-2044. [PMID: 33507183 DOI: 10.1039/d0cc07763a] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We develop for the first time an aptamer-mediated rolling circle amplification approach for label-free and sensitive detection of histone-modifying enzyme (HME) activity. This method can achieve femtomolar sensitivity for histone acetyltransferase Tip60 assay, which is the most sensitive HME assay reported so far. It can be further applied for inhibitor screening, enzyme kinetic analysis, and endogenous Tip60 measurement in cancer cells.
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Affiliation(s)
- Su Jiang
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, China.
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53
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Astroski JW, Akporyoe LK, Androphy EJ, Custer SK. Mutations in the COPI coatomer subunit α-COP induce release of Aβ-42 and amyloid precursor protein intracellular domain and increase tau oligomerization and release. Neurobiol Aging 2021; 101:57-69. [PMID: 33582567 DOI: 10.1016/j.neurobiolaging.2021.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 12/02/2020] [Accepted: 01/06/2021] [Indexed: 12/14/2022]
Abstract
Understanding the cellular processes that lead to Alzheimer's disease (AD) is critical, and one key lies in the genetics of families with histories of AD. Mutations a complex known as COPI were found in families with AD. The COPI complex is involved in protein processing and trafficking. Intriguingly, several recent publications have found components of the COPI complex can affect the metabolism of pathogenic AD proteins. We reduced levels of the COPI subunit α-COP, altering maturation and cleavage of amyloid precursor protein (APP), resulting in decreased release of Aβ-42 and decreased accumulation of the AICD. Depletion of α-COP reduced uptake of proteopathic Tau seeds and reduces intracellular Tau self-association. Expression of AD-associated mutant α-COP altered APP processing, resulting in increased release of Aβ-42 and increased intracellular Tau aggregation and release of Tau oligomers. These results show that COPI coatomer function modulates processing of both APP and Tau, and expression of AD-associated α-COP confers a toxic gain of function, resulting in potentially pathogenic changes in both APP and Tau.
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Affiliation(s)
- Jacob W Astroski
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Elliot J Androphy
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Sara K Custer
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA.
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54
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Dimeric Transmembrane Orientations of APP/C99 Regulate γ-Secretase Processing Line Impacting Signaling and Oligomerization. iScience 2020; 23:101887. [PMID: 33367225 PMCID: PMC7749410 DOI: 10.1016/j.isci.2020.101887] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/21/2020] [Accepted: 11/25/2020] [Indexed: 12/22/2022] Open
Abstract
Amyloid precursor protein (APP) cleavage by the β-secretase produces the C99 transmembrane (TM) protein, which contains three dimerization-inducing Gly-x-x-x-Gly motifs. We demonstrate that dimeric C99 TM orientations regulate the precise cleavage lines by γ-secretase. Of all possible dimeric orientations imposed by a coiled-coil to the C99 TM domain, the dimer containing the 33Gly-x-x-x-Gly37 motif in the interface promoted the Aβ42 processing line and APP intracellular domain-dependent gene transcription, including the induction of BACE1 mRNA, enhancing amyloidogenic processing and signaling. Another orientation exhibiting the 25Gly-x-x-x-Gly29 motif in the interface favored processing to Aβ43/40. It induced significantly less gene transcription, while promoting formation of SDS-resistant "Aβ-like" oligomers, reminiscent of Aβ peptide oligomers. These required both Val24 of a pro-β motif and the 25Gly-x-x-x-Gly29 interface. Thus, crossing angles imposed by precise dimeric orientations control γ-secretase initial cleavage at Aβ48 or Aβ49, linking the former to enhanced signaling and Aβ42 production.
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55
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Li Z, Rasmussen LJ. TIP60 in aging and neurodegeneration. Ageing Res Rev 2020; 64:101195. [PMID: 33091598 DOI: 10.1016/j.arr.2020.101195] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/29/2020] [Accepted: 10/14/2020] [Indexed: 02/06/2023]
Abstract
Epigenetic modification of chromatin, including histone methylation and acetylation, plays critical roles in eukaryotic cells and has a significant impact on chromatin structure/accessibility, gene regulation and, susceptibility to aging, neurodegenerative disease, cancer, and other age-related diseases. This article reviews the current advances on TIP60/KAT5, a major histone acetyltransferase with diverse functions in eukaryotes, with emphasis on its regulation of autophagy, proteasome-dependent protein turnover, RNA transcription, DNA repair, circadian rhythms, learning and memory, and other neurological functions implicated in aging and neurodegeneration. Moreover, the promising therapeutic potential of TIP60 is discussed to target Alzheimer's disease and other neurological diseases.
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56
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Lauer AA, Mett J, Janitschke D, Thiel A, Stahlmann CP, Bachmann CM, Ritzmann F, Schrul B, Müller UC, Stein R, Riemenschneider M, Grimm HS, Hartmann T, Grimm MOW. Regulatory feedback cycle of the insulin-degrading enzyme and the amyloid precursor protein intracellular domain: Implications for Alzheimer's disease. Aging Cell 2020; 19:e13264. [PMID: 33128835 PMCID: PMC7681056 DOI: 10.1111/acel.13264] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 09/16/2020] [Accepted: 10/02/2020] [Indexed: 12/04/2022] Open
Abstract
One of the major pathological hallmarks of Alzheimer´s disease (AD) is an accumulation of amyloid‐β (Aβ) in brain tissue leading to formation of toxic oligomers and senile plaques. Under physiological conditions, a tightly balanced equilibrium between Aβ‐production and ‐degradation is necessary to prevent pathological Aβ‐accumulation. Here, we investigate the molecular mechanism how insulin‐degrading enzyme (IDE), one of the major Aβ‐degrading enzymes, is regulated and how amyloid precursor protein (APP) processing and Aβ‐degradation is linked in a regulatory cycle to achieve this balance. In absence of Aβ‐production caused by APP or Presenilin deficiency, IDE‐mediated Aβ‐degradation was decreased, accompanied by a decreased IDE activity, protein level, and expression. Similar results were obtained in cells only expressing a truncated APP, lacking the APP intracellular domain (AICD) suggesting that AICD promotes IDE expression. In return, APP overexpression mediated an increased IDE expression, comparable results were obtained with cells overexpressing C50, a truncated APP representing AICD. Beside these genetic approaches, also AICD peptide incubation and pharmacological inhibition of the γ‐secretase preventing AICD production regulated IDE expression and promoter activity. By utilizing CRISPR/Cas9 APP and Presenilin knockout SH‐SY5Y cells results were confirmed in a second cell line in addition to mouse embryonic fibroblasts. In vivo, IDE expression was decreased in mouse brains devoid of APP or AICD, which was in line with a significant correlation of APP expression level and IDE expression in human postmortem AD brains. Our results show a tight link between Aβ‐production and Aβ‐degradation forming a regulatory cycle in which AICD promotes Aβ‐degradation via IDE and IDE itself limits its own production by degrading AICD.
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Affiliation(s)
- Anna A. Lauer
- Experimental Neurology Saarland University Homburg/Saar Germany
| | - Janine Mett
- Experimental Neurology Saarland University Homburg/Saar Germany
- Biosciences Zoology/Physiology‐Neurobiology Faculty NT‐Natural Science and Technology Saarland University Saarbrücken Germany
| | | | - Andrea Thiel
- Experimental Neurology Saarland University Homburg/Saar Germany
| | | | | | - Felix Ritzmann
- Department of Internal Medicine V – Pulmonology Allergology, Respiratory Intensive Care Medicine Saarland University Hospital Homburg/Saar Germany
| | - Bianca Schrul
- Medical Biochemistry and Molecular Biology Center for Molecular Signaling (PZMS) Faculty of Medicine Saarland University Homburg/Saar Germany
| | - Ulrike C. Müller
- Department of Functional Genomics Institute of Pharmacy and Molecular Biotechnology Heidelberg University Germany
| | - Reuven Stein
- Department of Neurology George S. Wise Faculty of Life Sciences Tel Aviv University Ramat Aviv Israel
| | | | - Heike S. Grimm
- Experimental Neurology Saarland University Homburg/Saar Germany
| | - Tobias Hartmann
- Experimental Neurology Saarland University Homburg/Saar Germany
- Deutsches Institut für DemenzPrävention (DIDP) Saarland University Homburg/Saar Germany
| | - Marcus O. W. Grimm
- Experimental Neurology Saarland University Homburg/Saar Germany
- Deutsches Institut für DemenzPrävention (DIDP) Saarland University Homburg/Saar Germany
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57
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Chan WWR, Li W, Chang RCC, Lau KF. ARF6-Rac1 signaling-mediated neurite outgrowth is potentiated by the neuronal adaptor FE65 through orchestrating ARF6 and ELMO1. FASEB J 2020; 34:16397-16413. [PMID: 33047393 DOI: 10.1096/fj.202001703r] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 09/13/2020] [Accepted: 10/02/2020] [Indexed: 12/24/2022]
Abstract
Ras-related C3 botulinum toxin substrate 1 (Rac1) is a member of the Rho family of GTPases that functions as a molecular switch to regulate many important cellular events including actin cytoskeleton remodeling during neurite outgrowth. Engulfment and cell motility 1 (ELMO1)-dedicator of cytokinesis 1 (DOCK180) is a bipartite guanine nucleotide exchange factor (GEF) complex that has been reported to activate Rac1 on the plasma membrane (PM). Emerging evidence suggests that the small GTPase ADP ribosylation factor 6 (ARF6) activates Rac1 via the ELMO1/DOCK180 complex. However, the exact mechanism by which ARF6 triggers ELMO1/DOCK180-mediated Rac1 signaling remains unclear. Here, we report that the neuronal scaffold protein FE65 serves as a functional link between ARF6 and ELMO1, allowing the formation of a multimeric signaling complex. Interfering with formation of this complex by transfecting either FE65-binding-defective mutants or FE65 siRNA attenuates both ARF6-ELMO1-mediated Rac1 activation and neurite elongation. Notably, the PM trafficking of ELMO1 is markedly decreased in cells with suppressed expression of either FE65 or ARF6. Likewise, this process is attenuated in the FE65-binding-defective mutants transfected cells. Moreover, overexpression of FE65 increases the amount of ELMO1 in the recycling endosome, an organelle responsible for returning proteins to the PM, whereas knockout of FE65 shows opposite effect. Together, our data indicates that FE65 potentiates ARF6-Rac1 signaling by orchestrating ARF6 and ELMO1 to promote the PM trafficking of ELMO1 via the endosomal recycling pathway, and thus, promotes Rac1-mediated neurite outgrowth.
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Affiliation(s)
- Wai Wa Ray Chan
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Wen Li
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong SAR, China.,Research Laboratory for Biomedical Optics and Molecular Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Raymond Chuen Chung Chang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, and State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Kwok-Fai Lau
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong SAR, China
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58
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Ravichandran P, Davis SA, Vashishtha H, Gucwa AL, Ginsburg DS. Nuclear Localization Is Not Required for Tip60 Tumor Suppressor Activity in Breast and Lung Cancer Cells. DNA Cell Biol 2020; 39:2077-2084. [PMID: 33155839 DOI: 10.1089/dna.2020.5980] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The Tip60 lysine acetyltransferase is a tumor suppressor in most cancers but an oncogene in prostate and gastric cancer. Tip60 is commonly found in the nucleus, where it acetylates proteins involved in transcription, DNA repair, and chromatin; however, it has also been shown to acetylate cytoplasmic targets. In this study, we investigated the relationship between Tip60 localization and breast and lung cancer. In cell fractionation experiments, cancer-derived cell lines showed a shift from nuclear to cytoplasmic endogenous Tip60 compared with cell lines derived from normal cells. With immunofluorescence, we observed four different localization patterns of overexpressed Tip60 and found that cancer cells had increased cytoplasmic localization of Tip60 compared with HEK-293 cells. The addition of a nuclear localization signal (NLS) increased the number of cells containing nuclear Tip60, whereas mutation of a putative endogenous NLS increased the number of cells with cytoplasmic Tip60. Overexpression of Tip60 increased cancer cell line sensitivity to paclitaxel regardless of changes in localization. These results suggest that dysregulation of Tip60 in breast and lung cancer is not limited to reduced expression but may also involve subcellular localization.
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Affiliation(s)
| | - Simon A Davis
- New York Structural Biology Center, New York, New York, USA
| | | | - Azad L Gucwa
- Department of Biology, Farmingdale State College, Farmingdale, New York, USA
| | - Daniel S Ginsburg
- Department of Natural Sciences, Immaculata University, Immaculata, Pennsylvania, USA
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59
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Creighton SD, Stefanelli G, Reda A, Zovkic IB. Epigenetic Mechanisms of Learning and Memory: Implications for Aging. Int J Mol Sci 2020; 21:E6918. [PMID: 32967185 PMCID: PMC7554829 DOI: 10.3390/ijms21186918] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/16/2020] [Accepted: 09/17/2020] [Indexed: 12/15/2022] Open
Abstract
The neuronal epigenome is highly sensitive to external events and its function is vital for producing stable behavioral outcomes, such as the formation of long-lasting memories. The importance of epigenetic regulation in memory is now well established and growing evidence points to altered epigenome function in the aging brain as a contributing factor to age-related memory decline. In this review, we first summarize the typical role of epigenetic factors in memory processing in a healthy young brain, then discuss the aspects of this system that are altered with aging. There is general agreement that many epigenetic marks are modified with aging, but there are still substantial inconsistencies in the precise nature of these changes and their link with memory decline. Here, we discuss the potential source of age-related changes in the epigenome and their implications for therapeutic intervention in age-related cognitive decline.
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Affiliation(s)
- Samantha D. Creighton
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; (S.D.C.); (G.S.)
| | - Gilda Stefanelli
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; (S.D.C.); (G.S.)
| | - Anas Reda
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S, Canada;
| | - Iva B. Zovkic
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; (S.D.C.); (G.S.)
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S, Canada;
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60
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Probst S, Krüger M, Kägi L, Thöni S, Schuppli D, Nitsch RM, Konietzko U. Fe65 is the sole member of its family that mediates transcription regulated by the amyloid precursor protein. J Cell Sci 2020; 133:jcs242917. [PMID: 32843577 DOI: 10.1242/jcs.242917] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 07/11/2020] [Indexed: 08/31/2023] Open
Abstract
The amyloid precursor protein (APP), a central molecule in Alzheimer's disease (AD), has physiological roles in cell adhesion and signaling, migration, neurite outgrowth and synaptogenesis. Intracellular adapter proteins mediate the function of transmembrane proteins. Fe65 (also known as APBB1) is a major APP-binding protein. Regulated intramembrane proteolysis (RIP) by γ-secretase releases the APP intracellular domain (AICD), together with the interacting proteins, from the membrane. We studied the impact of the Fe65 family (Fe65, and its homologs Fe65L1 and Fe65L2, also known as APBB2 and APBB3, respectively) on the nuclear signaling function of the AICD. All Fe65 family members increased amyloidogenic processing of APP, generating higher levels of β-cleaved APP stubs and AICD. However, Fe65 was the only family member supporting AICD translocation to nuclear spots and its transcriptional activity. Using a recently established transcription assay, we dissected the transcriptional activity of Fe65 and provide strong evidence that Fe65 represents a transcription factor. We show that Fe65 relies on the lysine acetyltransferase Tip60 (also known as KAT5) for nuclear translocation. Furthermore, inhibition of APP cleavage reduces nuclear Tip60 levels, but this does not occur in Fe65-knockout cells. The rate of APP cleavage therefore regulates the nuclear translocation of AICD-Fe65-Tip60 (AFT) complexes, to promote transcription by Fe65.
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Affiliation(s)
- Sabine Probst
- Institute for Regenerative Medicine - IREM, University of Zurich, Campus Schlieren, Wagistrasse 12, 8952 Schlieren - Zurich, Switzerland
| | - Maik Krüger
- Institute for Regenerative Medicine - IREM, University of Zurich, Campus Schlieren, Wagistrasse 12, 8952 Schlieren - Zurich, Switzerland
| | - Larissa Kägi
- Institute for Regenerative Medicine - IREM, University of Zurich, Campus Schlieren, Wagistrasse 12, 8952 Schlieren - Zurich, Switzerland
| | - Sarina Thöni
- Institute for Regenerative Medicine - IREM, University of Zurich, Campus Schlieren, Wagistrasse 12, 8952 Schlieren - Zurich, Switzerland
| | - Daniel Schuppli
- Institute for Regenerative Medicine - IREM, University of Zurich, Campus Schlieren, Wagistrasse 12, 8952 Schlieren - Zurich, Switzerland
| | - Roger M Nitsch
- Institute for Regenerative Medicine - IREM, University of Zurich, Campus Schlieren, Wagistrasse 12, 8952 Schlieren - Zurich, Switzerland
| | - Uwe Konietzko
- Institute for Regenerative Medicine - IREM, University of Zurich, Campus Schlieren, Wagistrasse 12, 8952 Schlieren - Zurich, Switzerland
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61
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Liu YC, Hsu WL, Ma YL, Lee EHY. Melatonin Induction of APP Intracellular Domain 50 SUMOylation Alleviates AD through Enhanced Transcriptional Activation and Aβ Degradation. Mol Ther 2020; 29:376-395. [PMID: 32950104 PMCID: PMC7791018 DOI: 10.1016/j.ymthe.2020.09.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 07/06/2020] [Accepted: 09/01/2020] [Indexed: 12/18/2022] Open
Abstract
The amyloid precursor protein (APP) intracellular domain (AICD) is implicated in the pathogenesis of Alzheimer’s disease (AD), but post-translational modification of AICD has rarely been studied and its role in AD is unknown. In this study, we examined the role and molecular mechanism of AICD SUMOylation in the pathogenesis of AD. We found that AICD is SUMO-modified by the SUMO E3 ligase protein inhibitor of activated STAT1 (PIAS1) in the hippocampus at Lys-43 predominantly, and that knockdown of PIAS1 decreases endogenous AICD SUMOylation. AICD SUMOylation increases AICD association with its binding protein Fe65 and increases AICD nuclear translocation. Furthermore, AICD SUMOylation increases AICD association with cyclic AMP-responsive element binding protein (CREB) and p65 and their DNA binding for transcriptional activation of neprilysin (NEP) and transthyretin (TTR), two major Aβ-degrading enzymes, respectively. Consequently, AICD SUMOylation decreases the Aβ level, Aβ oligomerization, and amyloid plaque deposits. It also rescues spatial memory deficits in APP/PS1 mice. Conversely, blockade of AICD SUMOylation at Lys-43 produces the opposite effects. Melatonin is identified as an endogenous stimulus that induces AICD SUMOylation. It also decreases the Aβ level and rescues reduction of PIAS1, NEP, and TTR expression in APP/PS1 mice. In this study, we demonstrate that AICD SUMOylation functions as a novel endogenous defense mechanism to combat AD.
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Affiliation(s)
- Yen-Chen Liu
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan; Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Wei-Lun Hsu
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Yun-Li Ma
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Eminy H Y Lee
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan; Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan.
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62
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Ristori E, Donnini S, Ziche M. New Insights Into Blood-Brain Barrier Maintenance: The Homeostatic Role of β-Amyloid Precursor Protein in Cerebral Vasculature. Front Physiol 2020; 11:1056. [PMID: 32973564 PMCID: PMC7481479 DOI: 10.3389/fphys.2020.01056] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/31/2020] [Indexed: 12/11/2022] Open
Abstract
Cerebrovascular homeostasis is maintained by the blood-brain barrier (BBB), a highly selective structure that separates the peripheral blood circulation from the brain and protects the central nervous system (CNS). Dysregulation of BBB function is the precursor of several neurodegenerative diseases including Alzheimer’s disease (AD) and cerebral amyloid angiopathy (CAA), both related to β-amyloid (Aβ) accumulation and deposition. The origin of BBB dysfunction before and/or during CAA and AD onset is not known. Several studies raise the possibility that vascular dysfunction could be an early step in these diseases and could even precede significant Aβ deposition. Though accumulation of neuron-derived Aβ peptides is considered the primary influence driving AD and CAA pathogenesis, recent studies highlighted the importance of the physiological role of the β-amyloid precursor protein (APP) in endothelial cell homeostasis, suggesting a potential role of this protein in maintaining vascular stability. In this review, we will discuss the physiological function of APP and its cleavage products in the vascular endothelium. We further suggest how loss of APP homeostatic regulation in the brain vasculature could lead toward pathological outcomes in neurodegenerative disorders.
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Affiliation(s)
- Emma Ristori
- Department of Life Sciences, University of Siena, Siena, Italy
| | - Sandra Donnini
- Department of Life Sciences, University of Siena, Siena, Italy
| | - Marina Ziche
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
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63
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Jiang M, Vanan S, Tu HT, Zhang W, Zhang ZW, Chia SY, Jang SE, Zeng XX, Yu WP, Xu J, Guo KH, Zeng L. Amyloid precursor protein intracellular domain-dependent regulation of FOXO3a inhibits adult hippocampal neurogenesis. Neurobiol Aging 2020; 95:250-263. [PMID: 32866886 DOI: 10.1016/j.neurobiolaging.2020.07.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 07/14/2020] [Accepted: 07/29/2020] [Indexed: 10/23/2022]
Abstract
The amyloid precursor protein (APP) intracellular domain (AICD) is a metabolic by-product of APP produced through sequential proteolytic cleavage by α-, β-, and γ-secretases. The interaction between AICD and Fe65 has been reported to impair adult neurogenesis in vivo. However, the exact role of AICD in mediating neural stem cell fate remains unclear. To identify the role of AICD in neuronal proliferation and differentiation, as well as to clarify the molecular mechanisms underlying the role of AICD in neurogenesis, we first generated a mouse model expressing the Rosa26-based AICD transgene. AICD overexpression did not alter the spatiotemporal expression pattern of full-length APP or accumulation of its metabolites. In addition, AICD decreased the newly generated neural progenitor cell (NPC) pool, inhibited the proliferation and differentiation efficiency of NPCs, and increased cell death both in vitro and in vivo. Given that abnormal neurogenesis is often associated with depression-like behavior in adult mice, we conducted a forced swim test and tail suspension test with AICD mice and found a depression-like behavioral phenotype in AICD transgenic mice. Moreover, AICD stimulated FOXO3a transcriptional activation, which in turn negatively regulated AICD. In addition, functional loss of FOXO3a in NPCs derived from the hippocampal dentate gyrus of adult AICD transgenic mice rescued neurogenesis defects. AICD also increased the mRNA expression of FOXO3a target genes related to neurogenesis and cell death. These results suggest that FOXO3a is the functional target of AICD in neurogenesis regulation. Our study reveals the role of AICD in mediating neural stem cell fate to maintain homeostasis during brain development via interaction with FOXO3a.
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Affiliation(s)
- Mei Jiang
- Department of Neurobiology and Anatomy, Sun Yat-Sen University Zhongshan School of Medicine, Guangzhou, PR China; Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore
| | - Sarivin Vanan
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore
| | - Hai-Tao Tu
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore
| | - Wei Zhang
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore
| | - Zhi-Wei Zhang
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore
| | - Sook-Yoong Chia
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore
| | - Se Eun Jang
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore
| | - Xiao-Xia Zeng
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore
| | - Wei-Ping Yu
- Animal Gene Editing Laboratory, Biological resource Centre, A∗STAR, Singapore; Institute of Molecular and Cell Biology, A∗STAR, Proteos, Singapore
| | - Jie Xu
- Department of Neurobiology and Anatomy, Sun Yat-Sen University Zhongshan School of Medicine, Guangzhou, PR China.
| | - Kai-Hua Guo
- Department of Neurobiology and Anatomy, Sun Yat-Sen University Zhongshan School of Medicine, Guangzhou, PR China.
| | - Li Zeng
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore; Neuroscience and Behavioral Disorders Program, DUKE-NUS Graduate Medical School, Singapore; Lee Kong Chian School of Medicine, Nanyang Technology University, Novena Campus, Singapore.
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64
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Roda AR, Montoliu-Gaya L, Villegas S. The Role of Apolipoprotein E Isoforms in Alzheimer's Disease. J Alzheimers Dis 2020; 68:459-471. [PMID: 30775980 DOI: 10.3233/jad-180740] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Alzheimer's disease (AD), the most common type of dementia worldwide, is characterized by high levels of amyloid-β (Aβ) peptide and hyperphosphorylated tau protein. Genetically, the ɛ4 allele of apolipoprotein E (ApoE) has been established as the major risk factor for developing late-onset AD (LOAD), the most common form of the disease. Although the role ApoE plays in AD is still not completely understood, a differential role of its isoforms has long been known. The current review compiles the involvement of ApoE isoforms in amyloid-β protein precursor transcription, Aβ aggregation and clearance, synaptic plasticity, neuroinflammation, lipid metabolism, mitochondrial function, and tau hyperphosphorylation. Due to the complexity of LOAD, an accurate description of the interdependence among all the related molecular mechanisms involved in the disease is needed for developing successful therapies.
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Affiliation(s)
- Alejandro R Roda
- Protein Design and Immunotherapy Group, Departament de Bioquímica i Biologia Molecular, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - Laia Montoliu-Gaya
- Protein Design and Immunotherapy Group, Departament de Bioquímica i Biologia Molecular, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain.,Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Sandra Villegas
- Protein Design and Immunotherapy Group, Departament de Bioquímica i Biologia Molecular, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
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65
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Abstract
In this issue, an article by Tiepolt et al. shows that PET scanning using [11C]PiB can demonstrate both cerebral blood flow (CBF) changes and amyloid-β (Aβ) deposition in patients with mild cognitive dysfunction or mild dementia of Alzheimer’s disease (AD). The CBF changes can be determined because the early scan counts (1–9 minutes) reflect the flow of the radiotracer in the blood passing through the brain, while the Aβ levels are measured by later scan counts (40–70 minutes) after the radiotracer has been cleared from regions to which the radiotracer did not bind. Thus, two different diagnostic measures are obtained with a single injection. Unexpectedly, the mild patients with Aβ positivity had scan data with only a weak relationship to memory, while the relationships to executive function and language function were relatively strong. This divergence of findings from studies of severely impaired patients highlights the importance of determining how AD pathology affects the brain. A possibility suggested in this commentary is that Aβ deposits occur early in AD and specifically in critical areas of the neocortex affected only later by the neurofibrillary pathology indicating a different role of the amyloid-β protein precursor (AβPP) in the development of those neocortical regions, and a separate component of AD pathology may selectively impact functions of these neocortical regions. The effects of adverse AβPP metabolism in the medial temporal and brainstem regions occur later possibly because of different developmental issues, and the later, different pathology is clearly more cognitively and socially devastating.
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Affiliation(s)
- J Wesson Ashford
- War Related Illness and Injury Study Center, VA Palo Alto Health Care System and Department of Psychiatry & Behavioral Sciences, Stanford University, Palo Alto, USA
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66
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Intramembrane proteolysis of an extracellular serine protease, epithin/PRSS14, enables its intracellular nuclear function. BMC Biol 2020; 18:60. [PMID: 32493324 PMCID: PMC7271384 DOI: 10.1186/s12915-020-00787-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 04/29/2020] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Epithin/PRSS14, a type II transmembrane serine protease, is an emerging target of cancer therapy because of its critical roles in tumor progression and metastasis. In many circumstances, the protease, through its ectodomain shedding, exists as a soluble form and performs its proteolytic functions in extracellular environments increasing cellular invasiveness. The seemingly functional integrity of the soluble form raises the question of why the protease is initially made as a membrane-associated protein. RESULTS In this report, we show that the epithin/PRSS14 intracellular domain (EICD) can be released from the membrane by the action of signal peptide peptidase-like 2b (SPPL2b) after ectodomain shedding. The EICD preferentially localizes in the nucleus and can enhance migration, invasion, and metastasis of epithelial cancer when heterologously expressed. Unbiased RNA-seq analysis and subsequent antibody arrays showed that EICD could control the gene expression of chemokines involved in cell motility, by increasing their promoter activities. Finally, bioinformatics analysis provided evidence for the clinical significance of the intramembrane proteolysis of epithin/PRSS14 by revealing that the poor survival of estrogen receptor (ER)-negative breast cancer patients with high epithin/PRSS14 expression is further worsened by high levels of SPPL2b. CONCLUSIONS These results show that ectodomain shedding of epithin/PRSS14 can initiate a unique and synchronized bidirectional signal for cancer metastasis: extracellularly broadening proteolytic modification of the surrounding environment and intracellularly reprogramming the transcriptome for metastatic conversion. Clinically, this study also suggests that the intracellular function of epithin/PRSS14 should be considered for targeting this protease for anti-cancer treatment.
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67
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Maesako M, Sekula NM, Aristarkhova A, Feschenko P, Anderson LC, Berezovska O. Visualization of PS/γ-Secretase Activity in Living Cells. iScience 2020; 23:101139. [PMID: 32438286 PMCID: PMC7235286 DOI: 10.1016/j.isci.2020.101139] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 04/09/2020] [Accepted: 05/04/2020] [Indexed: 12/21/2022] Open
Abstract
A change in Presenilin (PS)/γ-secretase activity is linked to essential biological events as well as to the progression of many diseases. However, not much is known about how PS/γ-secretase activity is spatiotemporally regulated in cells. One of the limitations is lack of tools to directly monitor dynamic behavior of the PS/γ-secretase in intact/live cells. Here we present successful development and validation of the Förster resonance energy transfer (FRET)-based biosensors that enable quantitative monitoring of endogenous PS/γ-secretase activity in live cells longitudinally on a cell-by-cell basis. Using these FRET biosensors, we uncovered that PS/γ-secretase activity is heterogeneously regulated among live neurons.
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Affiliation(s)
- Masato Maesako
- Alzheimer's Disease Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, 114, 16th Street, Charlestown, MA 02129, USA.
| | - Nicole M Sekula
- Alzheimer's Disease Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, 114, 16th Street, Charlestown, MA 02129, USA
| | - Anna Aristarkhova
- Alzheimer's Disease Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, 114, 16th Street, Charlestown, MA 02129, USA
| | - Polina Feschenko
- Alzheimer's Disease Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, 114, 16th Street, Charlestown, MA 02129, USA
| | - Lauren C Anderson
- Alzheimer's Disease Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, 114, 16th Street, Charlestown, MA 02129, USA
| | - Oksana Berezovska
- Alzheimer's Disease Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, 114, 16th Street, Charlestown, MA 02129, USA.
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68
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Hicks D, Jones A, Pickering-Brown S, Hooper N. The cellular expression and proteolytic processing of the amyloid precursor protein is independent of TDP-43. Biosci Rep 2020; 40:BSR20200435. [PMID: 32301481 PMCID: PMC7189496 DOI: 10.1042/bsr20200435] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/03/2020] [Accepted: 04/06/2020] [Indexed: 02/07/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative condition, of which one of the cardinal pathological hallmarks is the extracellular accumulation of amyloid β (Aβ) peptides. These peptides are generated via proteolysis of the amyloid precursor protein (APP), in a manner dependent on the β-secretase, BACE1 and the multicomponent γ-secretase complex. Recent data also suggest a contributory role in AD of transactive response DNA binding protein 43 (TDP-43). There is little insight into a possible mechanism linking TDP-43 and APP processing. To this end, we used cultured human neuronal cells to investigate the ability of TDP-43 to interact with APP and modulate its proteolytic processing. Immunocytochemistry showed TDP-43 to be spatially segregated from both the extranuclear APP holoprotein and its nuclear C-terminal fragment. The latter (APP intracellular domain) was shown to predominantly localise to nucleoli, from which TDP-43 was excluded. Furthermore, neither overexpression of each of the APP isoforms nor siRNA-mediated knockdown of APP had any effect on TDP-43 expression. Doxycycline-stimulated overexpression of TDP-43 was explored in an inducible cell line. Overexpression of TDP-43 had no effect on expression of the APP holoprotein, nor any of the key proteins involved in its proteolysis. Furthermore, increased TDP-43 expression had no effect on BACE1 enzymatic activity or immunoreactivity of Aβ1-40, Aβ1-42 or the Aβ1-40:Aβ1-42 ratio. Also, siRNA-mediated knockdown of TDP-43 had no effect on BACE1 immunoreactivity. Taken together, these data indicate that TDP-43 function and/or dysfunction in AD is likely independent from dysregulation of APP expression and proteolytic processing and Aβ generation.
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Affiliation(s)
- David A. Hicks
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Alys C. Jones
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Stuart M. Pickering-Brown
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Nigel M. Hooper
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
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69
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Genetic Dissection of Alzheimer's Disease Using Drosophila Models. Int J Mol Sci 2020; 21:ijms21030884. [PMID: 32019113 PMCID: PMC7037931 DOI: 10.3390/ijms21030884] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 01/26/2020] [Accepted: 01/26/2020] [Indexed: 02/06/2023] Open
Abstract
Alzheimer’s disease (AD), a main cause of dementia, is the most common neurodegenerative disease that is related to abnormal accumulation of the amyloid β (Aβ) protein. Despite decades of intensive research, the mechanisms underlying AD remain elusive, and the only available treatment remains symptomatic. Molecular understanding of the pathogenesis and progression of AD is necessary to develop disease-modifying treatment. Drosophila, as the most advanced genetic model, has been used to explore the molecular mechanisms of AD in the last few decades. Here, we introduce Drosophila AD models based on human Aβ and summarize the results of their genetic dissection. We also discuss the utility of functional genomics using the Drosophila system in the search for AD-associated molecular mechanisms in the post-genomic era.
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70
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Britzolaki A, Saurine J, Klocke B, Pitychoutis PM. A Role for SERCA Pumps in the Neurobiology of Neuropsychiatric and Neurodegenerative Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:131-161. [PMID: 31646509 DOI: 10.1007/978-3-030-12457-1_6] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Calcium (Ca2+) is a fundamental regulator of cell fate and intracellular Ca2+ homeostasis is crucial for proper function of the nerve cells. Given the complexity of neurons, a constellation of mechanisms finely tunes the intracellular Ca2+ signaling. We are focusing on the sarco/endoplasmic reticulum (SR/ER) calcium (Ca2+)-ATPase (SERCA) pump, an integral ER protein. SERCA's well established role is to preserve low cytosolic Ca2+ levels ([Ca2+]cyt), by pumping free Ca2+ ions into the ER lumen, utilizing ATP hydrolysis. The SERCA pumps are encoded by three distinct genes, SERCA1-3, resulting in 12 known protein isoforms, with tissue-dependent expression patterns. Despite the well-established structure and function of the SERCA pumps, their role in the central nervous system is not clear yet. Interestingly, SERCA-mediated Ca2+ dyshomeostasis has been associated with neuropathological conditions, such as bipolar disorder, schizophrenia, Parkinson's disease and Alzheimer's disease. We summarize here current evidence suggesting a role for SERCA in the neurobiology of neuropsychiatric and neurodegenerative disorders, thus highlighting the importance of this pump in brain physiology and pathophysiology.
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Affiliation(s)
- Aikaterini Britzolaki
- Department of Biology & Center for Tissue Regeneration and Engineering at Dayton (TREND), University of Dayton, Dayton, OH, USA
| | - Joseph Saurine
- Department of Biology & Center for Tissue Regeneration and Engineering at Dayton (TREND), University of Dayton, Dayton, OH, USA
| | - Benjamin Klocke
- Department of Biology & Center for Tissue Regeneration and Engineering at Dayton (TREND), University of Dayton, Dayton, OH, USA
| | - Pothitos M Pitychoutis
- Department of Biology & Center for Tissue Regeneration and Engineering at Dayton (TREND), University of Dayton, Dayton, OH, USA.
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71
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Abstract
The Amyloid Precursor Protein (APP) is infamous for its proposed pivotal role in the pathogenesis of Alzheimer’s disease (AD). Much research on APP focusses on potential contributions to neurodegeneration, mostly based on mouse models with altered expression or mutated forms of APP. However, cumulative evidence from recent years indicates the indispensability of APP and its metabolites for normal brain physiology. APP contributes to the regulation of synaptic transmission, plasticity, and calcium homeostasis. It plays an important role during development and it exerts neuroprotective effects. Of particular importance is the soluble secreted fragment APPsα which mediates many of its physiological actions, often counteracting the effects of the small APP-derived peptide Aβ. Understanding the contribution of APP for normal functions of the nervous system is of high importance, both from a basic science perspective and also as a basis for generating new pathophysiological concepts and therapeutic approaches in AD. In this article, we review the physiological functions of APP and its metabolites, focusing on synaptic transmission, plasticity, calcium signaling, and neuronal network activity.
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Affiliation(s)
- Dimitri Hefter
- Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany.,RG Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Susann Ludewig
- Helmholtz Centre for Infection Research, Neuroinflammation and Neurodegeneration Group, Braunschweig, Germany.,Cellular Neurobiology, Zoological Institute, Technical University Braunschweig, Braunschweig, Germany
| | - Andreas Draguhn
- Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany
| | - Martin Korte
- Helmholtz Centre for Infection Research, Neuroinflammation and Neurodegeneration Group, Braunschweig, Germany.,Cellular Neurobiology, Zoological Institute, Technical University Braunschweig, Braunschweig, Germany
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72
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Jiang H, Jayadev S, Lardelli M, Newman M. A Review of the Familial Alzheimer's Disease Locus PRESENILIN 2 and Its Relationship to PRESENILIN 1. J Alzheimers Dis 2019; 66:1323-1339. [PMID: 30412492 DOI: 10.3233/jad-180656] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
PRESENILIN 1 (PSEN1) and PRESENILIN 2 (PSEN2) genes are loci for mutations causing familial Alzheimer's disease (fAD). However, the function of these genes and how they contribute to fAD pathogenesis has not been fully determined. This review provides a summary of the overlapping and independent functions of the PRESENILINS with a focus on the lesser studied PSEN2. As a core component of the γ-secretase complex, the PSEN2 protein is involved in many γ-secretase-related physiological activities, including innate immunity, Notch signaling, autophagy, and mitochondrial function. These physiological activities have all been associated with AD progression, indicating that PSEN2 plays a particular role in AD pathogenesis.
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Affiliation(s)
- Haowei Jiang
- Alzheimer's Disease Genetics Laboratory, Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Suman Jayadev
- Department of Neurology, University of Washington, Seattle, WA, USA
| | - Michael Lardelli
- Alzheimer's Disease Genetics Laboratory, Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Morgan Newman
- Alzheimer's Disease Genetics Laboratory, Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
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73
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Janitschke D, Nelke C, Lauer AA, Regner L, Winkler J, Thiel A, Grimm HS, Hartmann T, Grimm MOW. Effect of Caffeine and Other Methylxanthines on Aβ-Homeostasis in SH-SY5Y Cells. Biomolecules 2019; 9:E689. [PMID: 31684105 PMCID: PMC6920871 DOI: 10.3390/biom9110689] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 10/25/2019] [Accepted: 10/30/2019] [Indexed: 02/07/2023] Open
Abstract
Methylxanthines (MTX) are alkaloids derived from the purine-base xanthine. Whereas especially caffeine, the most prominent known MTX, has been formerly assessed to be detrimental, this point of view has changed substantially. MTXs are discussed to have beneficial properties in neurodegenerative diseases, however, the mechanisms of action are not completely understood. Here we investigate the effect of the naturally occurring caffeine, theobromine and theophylline and the synthetic propentofylline and pentoxifylline on processes involved in Alzheimer's disease (AD). All MTXs decreased amyloid-β (Aβ) level by shifting the amyloid precursor protein (APP) processing from the Aβ-producing amyloidogenic to the non-amyloidogenic pathway. The α-secretase activity was elevated whereas β-secretase activity was decreased. Breaking down the molecular mechanism, caffeine increased protein stability of the major α-secretase ADAM10, downregulated BACE1 expression and directly decreased β-secretase activity. Additionally, APP expression was reduced. In line with literature, MTXs reduced oxidative stress, decreased cholesterol and a decreased in Aβ1-42 aggregation. In conclusion, all MTXs act via the pleiotropic mechanism resulting in decreased Aβ and show beneficial properties with respect to AD in neuroblastoma cells. However, the observed effect strength was moderate, suggesting that MTXs should be integrated in a healthy diet rather than be used exclusively to treat or prevent AD.
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Affiliation(s)
- Daniel Janitschke
- Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany.
| | - Christopher Nelke
- Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany.
| | - Anna Andrea Lauer
- Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany.
| | - Liesa Regner
- Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany.
| | - Jakob Winkler
- Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany.
| | - Andrea Thiel
- Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany.
| | - Heike Sabine Grimm
- Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany.
| | - Tobias Hartmann
- Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany.
- Deutsches Institut für DemenzPrävention (DIDP), Saarland University, 66424 Homburg/Saar, Germany.
| | - Marcus Otto Walter Grimm
- Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany.
- Deutsches Institut für DemenzPrävention (DIDP), Saarland University, 66424 Homburg/Saar, Germany.
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74
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Genetic intolerance analysis as a tool for protein science. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1862:183058. [PMID: 31494120 DOI: 10.1016/j.bbamem.2019.183058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 08/21/2019] [Accepted: 08/30/2019] [Indexed: 01/04/2023]
Abstract
Recent advances in whole genome and exome sequencing have dramatically increased the database of human gene variations. There are now enough sequenced human exomes and genomes to begin to identify gene variations that are notable because they are NOT observed in sequenced human genomes, apparently because they are subject to "purifying selection", exemplifying genetic intolerance. Such "dysprocreative" gene variations are embryonic lethal or prevent reproduction through any one of a number of possible mechanisms. Here we review an emerging quantitative approach, "Missense Tolerance Ratio" (MTR) analysis, that is used to assess protein-encoding gene (cDNA) sequence intolerance to missense mutations based on analysis of the >100 K and growing number of currently available human genome and exome sequences. This approach is already useful for analyzing intolerance to mutations in cDNA segments with a resolution on the order of 90 bases. Moreover, as the number of sequenced genomes/exomes increases by orders of magnitude it may eventually be possible to assess mutational tolerance in a statistically robust manner at or near single site resolution. Here we focus on how cDNA intolerance analysis complements other bioinformatic methods to illuminate structure-folding-function relationships for the encoded proteins. A set of disease-linked membrane proteins is employed to provide examples.
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75
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The role of PTB domain containing adaptor proteins on PICALM-mediated APP endocytosis and localization. Biochem J 2019; 476:2093-2109. [DOI: 10.1042/bcj20180840] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 07/01/2019] [Accepted: 07/12/2019] [Indexed: 02/06/2023]
Abstract
AbstractOne hallmark of Alzheimer's disease (AD) is the presence of amyloid plaques, which mainly consist of the amyloid precursor protein (APP) cleavage product amyloid β (Aβ). For cleavage to occur, the APP must be endocytosed from the cell surface. The phosphatidylinositol binding clathrin assembly protein (PICALM) is involved in clathrin-mediated endocytosis and polymorphisms in and near the gene locus were identified as genetic risk factors for AD. PICALM overexpression enhances APP internalization and Aβ production. Furthermore, PICALM shuttles into the nucleus, but its function within the nucleus is still unknown. Using co-immunoprecipitation, we demonstrated an interaction between PICALM and APP, which is abrogated by mutation of the APP NPXY-motif. Since the NPXY-motif is an internalization signal that binds to phosphotryrosine-binding domain-containing adaptor proteins (PTB-APs), we hypothesized that PTB-APs can modulate the APP-PICALM interaction. We found that interaction between PICALM and the PTB-APs (Numb, JIP1b and GULP1) enhances the APP-PICALM interaction. Fluorescence activated cell sorting analysis and internalization assays revealed differentially altered APP cell surface levels and endocytosis rates that depended upon the presence of PICALM and co-expression of distinct PTB-APs. Additionally, we were able to show an impact of PICALM nuclear shuttling upon co-expression of PTB-APs and PICALM, with the magnitude of the effect depending on which PTB-AP was co-expressed. Taken together, our results indicate a modulating effect of PTB-APs on PICALM-mediated APP endocytosis and localization.
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76
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Lee YJ, Ch'ng TH. RIP at the Synapse and the Role of Intracellular Domains in Neurons. Neuromolecular Med 2019; 22:1-24. [PMID: 31346933 DOI: 10.1007/s12017-019-08556-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/12/2019] [Indexed: 12/18/2022]
Abstract
Regulated intramembrane proteolysis (RIP) occurs in a cell when transmembrane proteins are cleaved by intramembrane proteases such as secretases to generate soluble protein fragments in the extracellular environment and the cytosol. In the cytosol, these soluble intracellular domains (ICDs) have local functions near the site of cleavage or in many cases, translocate to the nucleus to modulate gene expression. While the mechanism of RIP is relatively well studied, the fate and function of ICDs for most substrate proteins remain poorly characterized. In neurons, RIP occurs in various subcellular compartments including at the synapse. In this review, we summarize current research on RIP in neurons, focusing specifically on synaptic proteins where the presence and function of the ICDs have been reported. We also briefly discuss activity-driven processing of RIP substrates at the synapse and the cellular machinery that support long-distance transport of ICDs from the synapse to the nucleus. Finally, we describe future challenges in this field of research in the context of understanding the contribution of ICDs in neuronal function.
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Affiliation(s)
- Yan Jun Lee
- Lee Kong Chian School of Medicine, Nanyang Technological University, Clinical Science Building, 11 Mandalay Road, 10-01-01 M, Singapore, 308232, Singapore.,Interdisciplinary Graduate School (IGS), Nanyang Technological University, Singapore, Singapore
| | - Toh Hean Ch'ng
- Lee Kong Chian School of Medicine, Nanyang Technological University, Clinical Science Building, 11 Mandalay Road, 10-01-01 M, Singapore, 308232, Singapore. .,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
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77
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Peng X, Williams J, Smallwood PM, Nathans J. Defining the binding interface of Amyloid Precursor Protein (APP) and Contactin3 (CNTN3) by site-directed mutagenesis. PLoS One 2019; 14:e0219384. [PMID: 31318883 PMCID: PMC6638891 DOI: 10.1371/journal.pone.0219384] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 06/22/2019] [Indexed: 11/19/2022] Open
Abstract
The Amyloid Precursor Protein (APP) and Contactin (CNTN) families of cell-surface proteins have been intensively studied in the context of neural development and neuropsychiatric diseases. Earlier studies demonstrated both genetic and biochemical interactions between the extracellular domains of APP and CNTN3, but their precise binding interfaces were not defined. In the present study, we have used binding assays between APP-alkaline phosphatase (AP) fusion proteins and CNTN-Fc fusion proteins, together with alanine substitution mutagenesis, to show that: (i) the second Fibronectin domain (Fn(2)) in CNTN3 mediates APP binding; (ii) the copper binding domain (CuBD) in APP mediates CNTN3 binding; and (iii) the most important amino acids for APP-CNTN3 binding reside on one face of CNTN3-Fn(2) and on one face of APP-CuBD. These experiments define the regions of direct contact that mediate the binding interaction between APP and CNTN3.
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Affiliation(s)
- Xi Peng
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - John Williams
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Philip M. Smallwood
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jeremy Nathans
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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78
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Matrone C, Iannuzzi F, Annunziato L. The Y 682ENPTY 687 motif of APP: Progress and insights toward a targeted therapy for Alzheimer's disease patients. Ageing Res Rev 2019; 52:120-128. [PMID: 31039414 DOI: 10.1016/j.arr.2019.04.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 03/04/2019] [Accepted: 04/10/2019] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disorder for which no curative treatments, disease modifying strategies or effective symptomatic therapies exist. Current pharmacologic treatments for AD can only decelerate the progression of the disease for a short time, often at the cost of severe side effects. Therefore, there is an urgent need for biomarkers able to diagnose AD at its earliest stages, to conclusively track disease progression, and to accelerate the clinical development of innovative therapies. Scientific research and economic efforts for the development of pharmacotherapies have recently homed in on the hypothesis that neurotoxic β-amyloid (Aβ) peptides in their oligomeric or fibrillary forms are primarily responsible for the cognitive impairment and neuronal death seen in AD. As such, modern pharmacologic approaches are largely based on reducing production by inhibiting β and γ secretase cleavage of the amyloid precursor protein (APP) or on dissolving existing cerebral Aβ plaques or to favor Aβ clearance from the brain. The following short review aims to persuade the reader of the idea that APP plays a much larger role in AD pathogenesis. APP plays a greater role in AD pathogenesis than its role as the precursor for Aβ peptides: both the abnormal cleavage of APP leading to Aβ peptide accumulation and the disruption of APP physiological functions contribute to AD pathogenesis. We summarize our recent results on the role played by the C-terminal APP motif -the Y682ENPTY68 motif- in APP function and dysfunction, and we provide insights into targeting the Tyr682 residue of APP as putative novel strategy in AD.
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79
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A fluorescent protein-readout for transcriptional activity reveals regulation of APP nuclear signaling by phosphorylation sites. Biol Chem 2019; 400:1191-1203. [DOI: 10.1515/hsz-2019-0125] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 05/14/2019] [Indexed: 11/15/2022]
Abstract
Abstract
Signaling pathways that originate at the plasma membrane, including regulated intramembrane proteolysis (RIP), enable extracellular cues to control transcription. We modified the yeast Gal4 transcription system to study the nuclear translocation of transcriptionally active complexes using the fluorescent protein citrine (Cit) as a reporter. This enabled highly sensitive quantitative analysis of transcription in situ at the single cell level. The Gal4/UAS-Cit transcription assay displayed a sigmoidal response limited by the number of integrated reporter cassettes. We validated the assay by analyzing nuclear translocation of the amyloid precursor protein (APP) intracellular domain (AICD) and confirmed the requirement of Fe65 for nuclear translocation of AICD. In addition to the strong on-off effects on transcriptional activity, the results of this assay establish that phosphorylation modifies nuclear signaling. The Y682F mutation in APP showed the strongest increase in Cit expression, underscoring its role in regulating Fe65 binding. Together, we established a highly sensitive fluorescent protein-based assay that can monitor transcriptional activity at the single cell level and demonstrate that AICD phosphorylation affects Fe65 nuclear activity. This assay also introduces a platform for future single cell-based drug screening methods for nuclear translocation.
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80
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Profiling of Alzheimer’s disease related genes in mild to moderate vitamin D hypovitaminosis. J Nutr Biochem 2019; 67:123-137. [DOI: 10.1016/j.jnutbio.2019.01.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 12/13/2018] [Accepted: 01/29/2019] [Indexed: 02/01/2023]
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81
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Gómez-Pinedo U, Galán L, Matías-Guiu JA, Pytel V, Moreno T, Guerrero-Sola A, Matías-Guiu J. Notch Signalling in the Hippocampus of Patients With Motor Neuron Disease. Front Neurosci 2019; 13:302. [PMID: 31024234 PMCID: PMC6460507 DOI: 10.3389/fnins.2019.00302] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/15/2019] [Indexed: 12/12/2022] Open
Abstract
Introduction The Notch signalling pathway regulates neuronal survival. It has some similarities with the APP signalling pathway, and competes with the latter for α- and γ-secretase proteolytic complexes. The objective of this study was to study the Notch signalling pathway in the hippocampi of patients with motor neuron disease. Methods We studied biological material from the autopsies of 12 patients with motor neuron disease and 4 controls. We analysed the molecular markers of the Notch and APP signalling pathways, TDP43, tau, and markers of neurogenesis. Results and Conclusion Low NICD expression suggests Notch signalling pathway inactivation in neurons. Inactivation of the pathway despite increased Notch1 expression is associated with a lack of α-secretase expression. We observed increased β-secretase expression associated with activation of the amyloid cascade of APP, leading to increases in amyloid-β and AICD peptides and decreased levels of Fe65. Inactivation of the Notch signalling pathway is an important factor in decreased neurogenic response in the hippocampi of patients with amyotrophic lateral sclerosis.
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Affiliation(s)
- Ulises Gómez-Pinedo
- Laboratory of Neurobiology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
| | - Lucía Galán
- Department of Neurology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
| | - Jordi A Matías-Guiu
- Department of Neurology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
| | - Vanesa Pytel
- Laboratory of Neurobiology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain.,Department of Neurology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
| | - Teresa Moreno
- Department of Neurology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
| | - Antonio Guerrero-Sola
- Department of Neurology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
| | - Jorge Matías-Guiu
- Laboratory of Neurobiology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain.,Department of Neurology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
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82
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Kuehner JN, Bruggeman EC, Wen Z, Yao B. Epigenetic Regulations in Neuropsychiatric Disorders. Front Genet 2019; 10:268. [PMID: 31019524 PMCID: PMC6458251 DOI: 10.3389/fgene.2019.00268] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/11/2019] [Indexed: 12/14/2022] Open
Abstract
Precise genetic and epigenetic spatiotemporal regulation of gene expression is critical for proper brain development, function and circuitry formation in the mammalian central nervous system. Neuronal differentiation processes are tightly regulated by epigenetic mechanisms including DNA methylation, histone modifications, chromatin remodelers and non-coding RNAs. Dysregulation of any of these pathways is detrimental to normal neuronal development and functions, which can result in devastating neuropsychiatric disorders, such as depression, schizophrenia and autism spectrum disorders. In this review, we focus on the current understanding of epigenetic regulations in brain development and functions, as well as their implications in neuropsychiatric disorders.
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Affiliation(s)
- Janise N Kuehner
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States
| | - Emily C Bruggeman
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States
| | - Zhexing Wen
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, United States.,Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States.,Department of Neurology, Emory University School of Medicine, Atlanta, GA, United States
| | - Bing Yao
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States
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83
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Kumar M, Kulshrestha R, Singh N, Jaggi AS. Expanding spectrum of anticancer drug, imatinib, in the disorders affecting brain and spinal cord. Pharmacol Res 2019; 143:86-96. [PMID: 30902661 DOI: 10.1016/j.phrs.2019.03.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 03/07/2019] [Accepted: 03/17/2019] [Indexed: 02/07/2023]
Abstract
Imatinib is a tyrosine kinase inhibitor and is used as a first line drug in the treatment of Philadelphia-chromosome-positive chronic myeloid leukaemia and gastrointestinal stromal tumors. Being tyrosine kinase inhibitor, imatinib modulates the activities of Abelson gene (c-Abl), Abelson related gene (ARG), platelet-derived growth factor receptor (PDGFR), FMS-like tyrosine kinase 3 (FLT3), lymphocyte-specific protein (Lck), mitogen activated protein kinase (MAPK), amyloid precursor protein intracellular domain (AICD), α-synuclein and the stem-cell factor receptor (c-kit). Studies have shown the role of imatinib in modulating the pathophysiological state of a number of disorders affecting brain and spinal cord such as Alzheimer's disease, Parkinson's disease, stroke, multiple sclerosis and spinal cord injury. The present review discusses the role of imatinib in the above described disorders and the possible mechanisms involved in these diseases.
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Affiliation(s)
- Manish Kumar
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab, 147002, India
| | | | - Nirmal Singh
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab, 147002, India
| | - Amteshwar Singh Jaggi
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, Punjab, 147002, India.
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84
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Law BM, Guest AL, Pullen MWJ, Perkinton MS, Williams RJ. Increased Foxo3a Nuclear Translocation and Activity is an Early Neuronal Response to βγ-Secretase-Mediated Processing of the Amyloid-β Protein Precursor: Utility of an AβPP-GAL4 Reporter Assay. J Alzheimers Dis 2019; 61:673-688. [PMID: 29254083 DOI: 10.3233/jad-170393] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Sequential cleavage of the amyloid-β protein precursor (AβPP) by BACE1 (β-secretase) followed by theγ-secretase complex, is strongly implicated in Alzheimer's disease (AD) but the initial cellular responses to these cleavage events are not fully defined. β-secretase-mediated AβPP processing yields an extracellular domain (sAβPPβ) and a C-terminal fragment of AβPP of 99 amino acids (C99). Subsequent cleavage by γ-secretase produces amyloid-β (Aβ) and an AβPP intracellular domain (AICD). A cellular screen based on the generation of AICD from an AβPP-Gal4 fusion protein was adapted by introducing familial AD (FAD) mutations into the AβPP sequence and linking the assay to Gal4-UAS driven luciferase and GFP expression, to identify responses immediately downstream of AβPP processing in neurons with a focus on the transcription factor Foxo3a which has been implicated in neurodegeneration. The K670N/M671L, E682K, E693G, and V717I FAD mutations and the A673T protective mutation, were introduced into the AβPP sequence by site directed mutagenesis. When expressed in mouse cortical neurons, AβPP-Gal4-UAS driven luciferase and GFP expression was substantially reduced by γ-secretase inhibitors, lowered by β-secretase inhibitors, and enhanced by α-secretase inhibitors suggesting that AICD is a product of the βγ-secretase pathway. AβPP-Gal4-UAS driven GFP expression was exploited to identify individual neurons undergoing amyloidogenic AβPP processing, revealing increased nuclear localization of Foxo3a and enhanced Foxo3a-mediated transcription downstream of AICD production. Foxo3a translocation was not driven by AICD directly but correlated with reduced Akt phosphorylation. Collectively this suggests that βγ-secretase-mediated AβPP processing couples to Foxo3a which could be an early neuronal signaling response in AD.
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Affiliation(s)
- Bernard M Law
- Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - Amy L Guest
- Department of Biology and Biochemistry, University of Bath, Bath, UK
| | | | | | - Robert J Williams
- Department of Biology and Biochemistry, University of Bath, Bath, UK
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85
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C-terminal fragments of amyloid precursor proteins increase cofilin phosphorylation by LIM kinase in cultured rat primary neurons. Neuroreport 2019; 30:38-45. [PMID: 30444792 DOI: 10.1097/wnr.0000000000001162] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Amyloid precursor proteins (APPs) are processed by β-, γ-, and ε-secretases and caspase-3 to generate C-terminal fragments of APP (APP-CTFs), which may contribute to the pathology of Alzheimer's disease (AD). In addition to amyloid plaques and neurofibrillary tangles, AD brains contain Hirano bodies, which are rod-like structures mostly composed of actin and the actin-binding protein, cofilin. However, the mechanisms underlying the formation of cofilin-actin rods are still unknown. In this study, we aim to elucidate the effects of APP-CTFs on the actin-depolymerizing factor [(ADF)/cofilin]. Our data indicate that transfection with APP-CT99 and APP-CT57 may increase the phosphorylation level of Ser3 of ADF/cofilin and Thr508 of LIM-kinase 1 in rat primary cortical neuronal cultures. S3 peptide, a synthetic peptide competitor of LIM-kinase 1 for ADF/cofilin phosphorylation and an inhibitor of APP-CTFs, induced ADF/cofilin phosphorylation. In comparison with the wild-type mouse, the APP-CT transgenic mouse showed increased immunoreactivity of phosphorylated cofilin (p-cofilin) in the brain. Treatment with DAPT, an inhibitor of γ-secretase, resulted in a decrease in p-cofilin protein level in the group transfected with full-length APP-695. Transfection with the mutant APP-CTF with a deleted YENPTY domain resulted in no significant increase in p-cofilin level. Thus, APP-CTFs induced cofilin phosphorylation to facilitate nuclear translocation. These results suggest a relationship between APP-CTFs and ADF/cofilin that may be suggestive of a new toxic pathway in the pathology of AD.
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86
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Kulas JA, Franklin WF, Smith NA, Manocha GD, Puig KL, Nagamoto-Combs K, Hendrix RD, Taglialatela G, Barger SW, Combs CK. Ablation of amyloid precursor protein increases insulin-degrading enzyme levels and activity in brain and peripheral tissues. Am J Physiol Endocrinol Metab 2019; 316:E106-E120. [PMID: 30422705 PMCID: PMC6417684 DOI: 10.1152/ajpendo.00279.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The amyloid precursor protein (APP) is a type I transmembrane glycoprotein widely studied for its role as the source of β-amyloid peptide, accumulation of which is causal in at least some cases of Alzheimer's disease (AD). APP is expressed ubiquitously and is involved in diverse biological processes. Growing bodies of evidence indicate connections between AD and somatic metabolic disorders related to type 2 diabetes, and App-/- mice show alterations in glycemic regulation. We find that App-/- mice have higher levels of insulin-degrading enzyme (IDE) mRNA, protein, and activity compared with wild-type controls. This regulation of IDE by APP was widespread across numerous tissues, including liver, skeletal muscle, and brain as well as cell types within neural tissue, including neurons, astrocytes, and microglia. RNA interference-mediated knockdown of APP in the SIM-A9 microglia cell line elevated IDE levels. Fasting levels of blood insulin were lower in App-/- than App+/+ mice, but the former showed a larger increase in response to glucose. These low basal levels may enhance peripheral insulin sensitivity, as App-/- mice failed to develop impairment of glucose tolerance on a high-fat, high-sucrose ("Western") diet. Insulin levels and insulin signaling were also lower in the App-/- brain; synaptosomes prepared from App-/- hippocampus showed diminished insulin receptor phosphorylation compared with App+/+ mice when stimulated ex vivo. These findings represent a new molecular link connecting APP to metabolic homeostasis and demonstrate a novel role for APP as an upstream regulator of IDE in vivo.
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Affiliation(s)
- Joshua A Kulas
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences , Grand Forks, North Dakota
| | - Whitney F Franklin
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch , Galveston, Texas
| | - Nicholas A Smith
- Department of Pathology, University of North Dakota School of Medicine and Health Sciences , Grand Forks, North Dakota
| | - Gunjan D Manocha
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences , Grand Forks, North Dakota
| | - Kendra L Puig
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences , Grand Forks, North Dakota
| | - Kumi Nagamoto-Combs
- Department of Pathology, University of North Dakota School of Medicine and Health Sciences , Grand Forks, North Dakota
| | - Rachel D Hendrix
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences , Little Rock Arkansas
| | - Giulio Taglialatela
- Department of Neurology, University of Texas Medical Branch , Galveston, Texas
| | - Steven W Barger
- Department of Geriatrics, University of Arkansas for Medical Sciences , Little Rock Arkansas
- Geriatric Research, Education and Clinical Center, Central Arkansas Veterans Healthcare System, Little Rock, Arkansas
| | - Colin K Combs
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences , Grand Forks, North Dakota
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87
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Krasinski CA, Zheng Q, Ivancic VA, Spratt DE, Lazo ND. The Longest Amyloid-β Precursor Protein Intracellular Domain Produced with Aβ42 Forms β-Sheet-Containing Monomers That Self-Assemble and Are Proteolyzed by Insulin-Degrading Enzyme. ACS Chem Neurosci 2018; 9:2892-2897. [PMID: 30067897 DOI: 10.1021/acschemneuro.8b00305] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease resulting in dementia. It is characterized pathologically by extracellular amyloid plaques composed mainly of deposited Aβ42 and intracellular neurofibrillary tangles formed by hyperphosphorylated tau protein. Recent clinical trials targeting Aβ have failed, suggesting that other polypeptides produced from the amyloid-β precursor protein (APP) may be involved in AD. An attractive polypeptide is AICD57, the longest APP intracellular domain (AICD) coproduced with Aβ42. Here, we show that AICD57 forms micelle-like assemblies that are proteolyzed by insulin-degrading enzyme (IDE), indicating that AICD57 monomers are in dynamic equilibrium with AICD57 assemblies. The N-terminal part of AICD57 monomer is not degraded, but its C-terminal part is hydrolyzed, particularly in the YENPTY motif that has been associated with the hyperphosphorylation of tau. Therefore, sustaining IDE activity well into old age holds promise for regulating levels of not only Aβ but also AICD in the aging brain.
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Affiliation(s)
- Claire A. Krasinski
- Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, Massachusetts 01610, United States
| | - Qiuchen Zheng
- Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, Massachusetts 01610, United States
| | - Valerie A. Ivancic
- Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, Massachusetts 01610, United States
| | - Donald E. Spratt
- Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, Massachusetts 01610, United States
| | - Noel D. Lazo
- Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, Massachusetts 01610, United States
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88
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Presenilin-mediated cleavage of APP regulates synaptotagmin-7 and presynaptic plasticity. Nat Commun 2018; 9:4780. [PMID: 30429473 PMCID: PMC6235831 DOI: 10.1038/s41467-018-06813-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 09/19/2018] [Indexed: 11/09/2022] Open
Abstract
Mutations of the intramembrane protease presenilin (PS) or of its main substrate, the amyloid precursor protein (APP), cause early-onset form of Alzheimer disease. PS and APP interact with proteins of the neurotransmitter release machinery without identified functional consequences. Here we report that genetic deletion of PS markedly decreases the presynaptic levels of the Ca2+ sensor synaptotagmin-7 (Syt7) leading to impaired synaptic facilitation and replenishment of synaptic vesicles. The regulation of Syt7 expression by PS occurs post-transcriptionally and depends on γ-secretase proteolytic activity. It requires the substrate APP as revealed by the combined genetic invalidation of APP and PS1, and in particular the APP-Cterminal fragments which interact with Syt7 and accumulate in synaptic terminals under pharmacological or genetic inhibition of γ-secretase. Thus, we uncover a role of PS in presynaptic mechanisms, through APP cleavage and regulation of Syt7, that highlights aberrant synaptic vesicle processing as a possible new pathway in AD. Mutations in presenilin, which cleaves amyloid precursor protein, cause familial Alzheimer’s Disease. Here, the authors show that loss of presenilin leads to loss of synaptotagmin 7, leading to impaired presynaptic release.
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89
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Steiner H, Fukumori A, Tagami S, Okochi M. Making the final cut: pathogenic amyloid-β peptide generation by γ-secretase. Cell Stress 2018; 2:292-310. [PMID: 31225454 PMCID: PMC6551803 DOI: 10.15698/cst2018.11.162] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Alzheimer´s disease (AD) is a devastating neurodegenerative disease of the elderly population. Genetic evidence strongly suggests that aberrant generation and/or clearance of the neurotoxic amyloid-β peptide (Aβ) is triggering the disease. Aβ is generated from the amyloid precursor protein (APP) by the sequential cleavages of β- and γ-secretase. The latter cleavage by γ-secretase, a unique and fascinating four-component protease complex, occurs in the APP transmembrane domain thereby releasing Aβ species of 37-43 amino acids in length including the longer, highly pathogenic peptides Aβ42 and Aβ43. The lack of a precise understanding of Aβ generation as well as of the functions of other γ-secretase substrates has been one factor underlying the disappointing failure of γ-secretase inhibitors in clinical trials, but on the other side also been a major driving force for structural and in depth mechanistic studies on this key AD drug target in the past few years. Here we review recent breakthroughs in our understanding of how the γ-secretase complex recognizes substrates, of how it binds and processes β-secretase cleaved APP into different Aβ species, as well as the progress made on a question of outstanding interest, namely how clinical AD mutations in the catalytic subunit presenilin and the γ-secretase cleavage region of APP lead to relative increases of Aβ42/43. Finally, we discuss how the knowledge emerging from these studies could be used to therapeutically target this enzyme in a safe way.
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Affiliation(s)
- Harald Steiner
- Biomedical Center (BMC), Metabolic Biochemistry, Ludwig-Maximilians-University Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Akio Fukumori
- Department of Aging Neurobiology, National Center for Geriatrics and Gerontology, Obu & Department of Mental Health Promotion, Osaka University Graduate School of Medicine, Toyonaka, Japan
| | - Shinji Tagami
- Neuropsychiatry, Department of Integrated Medicine, Division of Internal Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Masayasu Okochi
- Neuropsychiatry, Department of Integrated Medicine, Division of Internal Medicine, Osaka University Graduate School of Medicine, Suita, Japan
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90
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Voss AK, Thomas T. Histone Lysine and Genomic Targets of Histone Acetyltransferases in Mammals. Bioessays 2018; 40:e1800078. [PMID: 30144132 DOI: 10.1002/bies.201800078] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/01/2018] [Indexed: 01/08/2023]
Abstract
Histone acetylation has been recognized as an important post-translational modification of core nucleosomal histones that changes access to the chromatin to allow gene transcription, DNA replication, and repair. Histone acetyltransferases were initially identified as co-activators that link DNA-binding transcription factors to the general transcriptional machinery. Over the years, more chromatin-binding modes have been discovered suggesting direct interaction of histone acetyltransferases and their protein complex partners with histone proteins. While much progress has been made in characterizing histone acetyltransferase complexes biochemically, cell-free activity assay results are often at odds with in-cell histone acetyltransferase activities. In-cell studies suggest specific histone lysine targets, but broad recruitment modes, apparently not relying on specific DNA sequences, but on chromatin of a specific functional state. Here we review the evidence for general versus specific roles of individual nuclear lysine acetyltransferases in light of in vivo and in vitro data in the mammalian system.
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Affiliation(s)
- Anne K Voss
- Walter and Eliza Hall Institute of Medical Research, 3 1G Royal Parade, Parkville, Melbourne, Victoria, 3052, Australia
| | - Tim Thomas
- Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, Melbourne, Victoria, 3052, Australia
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91
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Ovchinnikov DA, Korn O, Virshup I, Wells CA, Wolvetang EJ. The Impact of APP on Alzheimer-like Pathogenesis and Gene Expression in Down Syndrome iPSC-Derived Neurons. Stem Cell Reports 2018; 11:32-42. [PMID: 29861166 PMCID: PMC6066957 DOI: 10.1016/j.stemcr.2018.05.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 05/03/2018] [Accepted: 05/04/2018] [Indexed: 12/17/2022] Open
Abstract
Early-onset Alzheimer disease (AD)-like pathology in Down syndrome is commonly attributed to an increased dosage of the amyloid precursor protein (APP) gene. To test this in an isogenic human model, we deleted the supernumerary copy of the APP gene in trisomic Down syndrome induced pluripotent stem cells or upregulated APP expression in euploid human pluripotent stem cells using CRISPRa. Cortical neuronal differentiation shows that an increased APP gene dosage is responsible for increased β-amyloid production, altered Aβ42/40 ratio, and deposition of the pyroglutamate (E3)-containing amyloid aggregates, but not for several tau-related AD phenotypes or increased apoptosis. Transcriptome comparisons demonstrate that APP has a widespread and temporally modulated impact on neuronal gene expression. Collectively, these data reveal an important role for APP in the amyloidogenic aspects of AD but challenge the idea that increased APP levels are solely responsible for increasing specific phosphorylated forms of tau or enhanced neuronal cell death in Down syndrome-associated AD pathogenesis.
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Affiliation(s)
- Dmitry A Ovchinnikov
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD 4072, Australia
| | - Othmar Korn
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD 4072, Australia
| | - Isaac Virshup
- Centre for Stem Cell Systems, MDHS, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Christine A Wells
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD 4072, Australia; Centre for Stem Cell Systems, MDHS, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Ernst J Wolvetang
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD 4072, Australia.
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92
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Mañucat-Tan NB, Saadipour K, Wang YJ, Bobrovskaya L, Zhou XF. Cellular Trafficking of Amyloid Precursor Protein in Amyloidogenesis Physiological and Pathological Significance. Mol Neurobiol 2018; 56:812-830. [PMID: 29797184 DOI: 10.1007/s12035-018-1106-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 05/03/2018] [Indexed: 12/26/2022]
Abstract
The accumulation of excess intracellular or extracellular amyloid beta (Aβ) is one of the key pathological events in Alzheimer's disease (AD). Aβ is generated from the cleavage of amyloid precursor protein (APP) by beta secretase-1 (BACE1) and gamma secretase (γ-secretase) within the cells. The endocytic trafficking of APP facilitates amyloidogenesis while at the cell surface, APP is predominantly processed in a non-amyloidogenic manner. Several adaptor proteins bind to both APP and BACE1, regulating their trafficking and recycling along the secretory and endocytic pathways. The phosphorylation of APP at Thr668 and BACE1 at Ser498, also influence their trafficking. Neurotrophins and proneurotrophins also influence APP trafficking through their receptors. In this review, we describe the molecular trafficking pathways of APP and BACE1 that lead to Aβ generation, the involvement of different signaling molecules or adaptor proteins regulating APP and BACE1 subcellular localization. We have also discussed how neurotrophins could modulate amyloidogenesis through their receptors.
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Affiliation(s)
- Noralyn Basco Mañucat-Tan
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, 5000, Australia.
| | - Khalil Saadipour
- Departments of Cell Biology, Physiology and Neuroscience, and Psychiatry, Skirball Institute of Biomolecular Medicine, New York University Langone School of Medicine, New York, NY, USA
| | - Yan-Jiang Wang
- Department of Neurology and Center for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042, China
| | - Larisa Bobrovskaya
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, 5000, Australia
| | - Xin-Fu Zhou
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, 5000, Australia.
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93
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O'Keefe L, Denton D. Using Drosophila Models of Amyloid Toxicity to Study Autophagy in the Pathogenesis of Alzheimer's Disease. BIOMED RESEARCH INTERNATIONAL 2018; 2018:5195416. [PMID: 29888266 PMCID: PMC5985114 DOI: 10.1155/2018/5195416] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 02/20/2018] [Accepted: 04/10/2018] [Indexed: 12/24/2022]
Abstract
Autophagy is a conserved catabolic pathway that involves the engulfment of cytoplasmic components such as large protein aggregates and organelles that are delivered to the lysosome for degradation. This process is important in maintaining neuronal function and raises the possibility of a role for autophagy in neurodegenerative diseases. Alzheimer's disease (AD) is the most prevalent form of these diseases and is characterized by the accumulation of amyloid plaques in the brain which arise due to the misfolding and aggregation of toxic peptides, including amyloid beta (Aβ). There is substantial evidence from both AD patients and animal models that autophagy is dysregulated in this disease. However, it remains to be determined whether this is protective or pathogenic as there is evidence that autophagy can act to promote the degradation as well as function in the generation of toxic Aβ peptides. Understanding the molecular details of the extensive crosstalk that occurs between the autophagic and endolysosomal cellular pathways is essential for identifying the molecular details of amyloid toxicity. Drosophila models that express the toxic proteins that aggregate in AD have been generated and have been shown to recapitulate hallmarks of the disease. Here we focus on what is known about the role of autophagy in amyloid toxicity in AD from mammalian models and how Drosophila models can be used to further investigate AD pathogenesis.
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Affiliation(s)
- Louise O'Keefe
- Department of Genetics and Evolution, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
- Hopwood Centre for Neurobiology, South Australian Health and Medical Research Institute, P.O. Box 11060, Adelaide, SA 5001, Australia
| | - Donna Denton
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA 5001, Australia
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94
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Matsuda S, Senda T. BRI2 as an anti-Alzheimer gene. Med Mol Morphol 2018; 52:1-7. [DOI: 10.1007/s00795-018-0191-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 04/18/2018] [Indexed: 12/16/2022]
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95
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Li W, Tam KMV, Chan WWR, Koon AC, Ngo JCK, Chan HYE, Lau KF. Neuronal adaptor FE65 stimulates Rac1-mediated neurite outgrowth by recruiting and activating ELMO1. J Biol Chem 2018; 293:7674-7688. [PMID: 29615491 DOI: 10.1074/jbc.ra117.000505] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 03/12/2018] [Indexed: 12/25/2022] Open
Abstract
Neurite outgrowth is a crucial process in developing neurons for neural network formation. Understanding the regulatory mechanisms of neurite outgrowth is essential for developing strategies to stimulate neurite regeneration after nerve injury and in neurodegenerative disorders. FE65 is a brain-enriched adaptor that stimulates Rac1-mediated neurite elongation. However, the precise mechanism by which FE65 promotes the process remains elusive. Here, we show that ELMO1, a subunit of ELMO1-DOCK180 bipartite Rac1 guanine nucleotide exchange factor (GEF), interacts with the FE65 N-terminal region. Overexpression of FE65 and/or ELMO1 enhances, whereas knockdown of FE65 or ELMO1 inhibits, neurite outgrowth and Rac1 activation. The effect of FE65 alone or together with ELMO1 is attenuated by an FE65 double mutation that disrupts FE65-ELMO1 interaction. Notably, FE65 is found to activate ELMO1 by diminishing ELMO1 intramolecular autoinhibitory interaction and to promote the targeting of ELMO1 to the plasma membrane, where Rac1 is activated. We also show that FE65, ELMO1, and DOCK180 form a tripartite complex. Knockdown of DOCK180 reduces the stimulatory effect of FE65-ELMO1 on Rac1 activation and neurite outgrowth. Thus, we identify a novel mechanism by which FE65 stimulates Rac1-mediated neurite outgrowth by recruiting and activating ELMO1.
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Affiliation(s)
- Wen Li
- From the School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin New Territories, Hong Kong
| | - Ka Ming Vincent Tam
- From the School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin New Territories, Hong Kong
| | - Wai Wa Ray Chan
- From the School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin New Territories, Hong Kong
| | - Alex Chun Koon
- From the School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin New Territories, Hong Kong
| | - Jacky Chi Ki Ngo
- From the School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin New Territories, Hong Kong
| | - Ho Yin Edwin Chan
- From the School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin New Territories, Hong Kong
| | - Kwok-Fai Lau
- From the School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin New Territories, Hong Kong
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96
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Guo XX, An S, Yang Y, Liu Y, Hao Q, Tang T, Xu TR. Emerging role of the Jun N-terminal kinase interactome in human health. Cell Biol Int 2018; 42:756-768. [DOI: 10.1002/cbin.10948] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 02/03/2018] [Indexed: 01/06/2023]
Affiliation(s)
- Xiao-Xi Guo
- Faculty of Life Science and Technology; Kunming University of Science and Technology; Kunming Yunnan 650500 China
| | - Su An
- Faculty of Life Science and Technology; Kunming University of Science and Technology; Kunming Yunnan 650500 China
| | - Yang Yang
- Faculty of Life Science and Technology; Kunming University of Science and Technology; Kunming Yunnan 650500 China
| | - Ying Liu
- Faculty of Life Science and Technology; Kunming University of Science and Technology; Kunming Yunnan 650500 China
| | - Qian Hao
- Faculty of Life Science and Technology; Kunming University of Science and Technology; Kunming Yunnan 650500 China
| | - Tao Tang
- Faculty of Medicine; Kunming University of Science and Technology; Kunming Yunnan 650500 China
| | - Tian-Rui Xu
- Faculty of Life Science and Technology; Kunming University of Science and Technology; Kunming Yunnan 650500 China
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97
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Trillaud-Doppia E, Boehm J. The Amyloid Precursor Protein Intracellular Domain Is an Effector Molecule of Metaplasticity. Biol Psychiatry 2018; 83:406-415. [PMID: 28168961 DOI: 10.1016/j.biopsych.2016.12.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 12/01/2016] [Accepted: 12/20/2016] [Indexed: 01/20/2023]
Abstract
BACKGROUND Human studies and mouse models of Alzheimer's disease suggest that the amyloid precursor protein (APP) can cause changes in synaptic plasticity and is contributing to the memory deficits seen in Alzheimer's disease. While most of these studies attribute these changes to the APP cleavage product Aβ, in recent years it became apparent that the APP intracellular domain (APP-ICD) might play a role in regulating synaptic plasticity. METHODS To separate the effects of APP-ICD on synaptic plasticity from Aβ-dependent effects, we created a chimeric APP in which the Aβ domain is exchanged for its homologous domain from the amyloid precursor-like protein 2. RESULTS We show that the expression of this chimeric APP has no effect on basal synaptic transmission or synaptic plasticity. However, a synaptic priming protocol, which in control cells has no effect on synaptic plasticity, leads to a complete block of subsequent long-term potentiation induction and a facilitation of long-term depression induction in neurons expressing chimeric APP. We show that the underlying mechanism for this effect on metaplasticity is caused by caspase cleavage of the APP-ICD and involves activation of ryanodine receptors. Our results shed light on the controversially discussed role of APP-ICD in regulating transcription. Because of the short timespan between synaptic priming and the effect on synaptic plasticity, it is unlikely that APP-ICD-dependent transcription is an underlying mechanism for the regulation of metaplasticity during this time period. CONCLUSIONS Our finding that the APP-ICD affects metaplasticity provides new insights into the altered regulation of synaptic plasticity during Alzheimer's disease.
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Affiliation(s)
- Emilie Trillaud-Doppia
- Département Neurosciences, Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada
| | - Jannic Boehm
- Département Neurosciences, Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada.
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98
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cAMP, cGMP and Amyloid β: Three Ideal Partners for Memory Formation. Trends Neurosci 2018; 41:255-266. [PMID: 29501262 DOI: 10.1016/j.tins.2018.02.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/25/2018] [Accepted: 02/01/2018] [Indexed: 02/03/2023]
Abstract
cAMP and cGMP are well established second messengers required for long-term potentiation (LTP) and memory formation/consolidation. By contrast, amyloid β (Aβ), mostly known as one of the main culprits for Alzheimer's disease (AD), has received relatively little attention in the context of plasticity and memory. Of note, however, low physiological concentrations of Aβ seem necessary for LTP induction and for memory formation. This should come as no surprise, since hormesis emerged as a central dogma in biology. Additionally, recent evidence indicates that Aβ is one of the downstream effectors for cAMP and cGMP to trigger synaptic plasticity and memory. We argue that these emerging findings depict a new scenario that should change the general view on the amyloidogenic pathway, and that could have significant implications for the understanding of AD and its pharmacological treatment in the future.
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99
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Kametani F, Hasegawa M. Reconsideration of Amyloid Hypothesis and Tau Hypothesis in Alzheimer's Disease. Front Neurosci 2018; 12:25. [PMID: 29440986 PMCID: PMC5797629 DOI: 10.3389/fnins.2018.00025] [Citation(s) in RCA: 566] [Impact Index Per Article: 80.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 01/12/2018] [Indexed: 12/20/2022] Open
Abstract
The so-called amyloid hypothesis, that the accumulation and deposition of oligomeric or fibrillar amyloid β (Aβ) peptide is the primary cause of Alzheimer's disease (AD), has been the mainstream concept underlying AD research for over 20 years. However, all attempts to develop Aβ-targeting drugs to treat AD have ended in failure. Here, we review recent findings indicating that the main factor underlying the development and progression of AD is tau, not Aβ, and we describe the deficiencies of the amyloid hypothesis that have supported the emergence of this idea.
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Affiliation(s)
- Fuyuki Kametani
- Department of Dementia and Higher Brain Function, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Masato Hasegawa
- Department of Dementia and Higher Brain Function, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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100
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Schauenburg L, Liebsch F, Eravci M, Mayer MC, Weise C, Multhaup G. APLP1 is endoproteolytically cleaved by γ-secretase without previous ectodomain shedding. Sci Rep 2018; 8:1916. [PMID: 29382944 PMCID: PMC5789831 DOI: 10.1038/s41598-018-19530-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 01/04/2018] [Indexed: 12/12/2022] Open
Abstract
Regulated intramembrane proteolysis of the amyloid precursor protein (APP) and its homologs, the APP like proteins APLP1 and APLP2, is typically a two-step process, which is initiated by ectodomain-shedding of the substrates by α- or β-secretases. Growing evidence, however, indicates that the cleavage process for APLP1 is different than for APP. Here, we describe that full-length APLP1, but not APP or APLP2, is uniquely cleaved by γ-secretase without previous ectodomain shedding. The new fragment, termed sAPLP1γ, was exclusively associated with APLP1, not APP, APLP2. We provide an exact molecular analysis showing that sAPLP1γ was uniquely generated by γ-secretase from full-length APLP1. Mass spectrometry analysis showed that the sAPLP1γ fragment and the longest Aβ-like peptide share the C-terminus. This novel mechanism of γ-secretase action is consistent with an ϵ-cut based upon the nature of the reaction in APP. We further demonstrate that the APLP1 transmembrane sequence is the critical determinant for γ-shedding and release of full-length APLP1. Moreover, the APLP1 TMS is sufficient to convert larger type-I membrane proteins like APP into direct γ-secretase substrates. Taken together, the direct cleavage of APLP1 is a novel feature of the γ-secretase prompting a re-thinking of γ-secretase activity modulation as a therapeutic strategy for Alzheimer disease.
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Affiliation(s)
- Linda Schauenburg
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany.,Sphingotec Therapeutics GmbH, Neuendorfstr. 15a, 16761, Hennigsdorf, Germany
| | - Filip Liebsch
- Department of Pharmacology & Therapeutics and Integrated Program in Neuroscience, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada
| | - Murat Eravci
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany
| | - Magnus C Mayer
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany.,Miltenyi Biotec GmbH, Robert-Koch-Strasse 1, 17166, Teterow, Germany
| | - Christoph Weise
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany
| | - Gerhard Multhaup
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany. .,Department of Pharmacology & Therapeutics and Integrated Program in Neuroscience, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada.
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